Nitrous oxide emissions in Chinese vegetable systems: A meta-analysis.

PubMed

Wang, Xiaozhong; Zou, Chunqin; Gao, Xiaopeng; Guan, Xilin; Zhang, Wushuai; Zhang, Yueqiang; Shi, Xiaojun; Chen, Xinping

2018-08-01

China accounts for more than half of the world's vegetable production, and identifying the contribution of vegetable production to nitrous oxide (N 2 O) emissions in China is therefore important. We performed a meta-analysis that included 153 field measurements of N 2 O emissions from 21 field studies in China. Our goal was to quantify N 2 O emissions and fertilizer nitrogen (N) based-emission factors (EFs) in Chinese vegetable systems and to clarify the effects of rates and types of N fertilizer in both open-field and greenhouse systems. The results indicated that the intensive vegetable systems in China had an average N 2 O emission of 3.91 kg N 2 O-N ha -1 and an EF of 0.69%. Although the EF was lower than the IPCC default value of 1.0%, the average N 2 O emission was generally greater than in other cropping systems due to greater input of N fertilizers. The EFs were similar in greenhouse vs. open-field systems but N 2 O emissions were about 1.4 times greater in greenhouses. The EFs were not affected by N rate, but N 2 O emissions for both open-field and greenhouse systems increased with N rate. The total and fertilizer-induced N 2 O emissions, as well as EFs, were unaffected by the type of fertilizers in greenhouse system under same N rates. In addition to providing basic information about N 2 O emissions from Chinese vegetable systems, the results suggest that N 2 O emissions could be reduced without reducing yields by treating vegetable systems in China with a combination of synthetic N fertilizer and manure at optimized economic rates. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fungal associations of roots of dominant and sub-dominant plants in high-alpine vegetation systems with special reference to mycorrhiza.

PubMed

Haselwandter, K; Read, D J

1980-04-01

Types of root infection were analysed in healthy dominant and sub-dominant plants of zonal and azonal vegetation above the timberline in the Central and Northern Calcareous Alps of Austria. In the open nival zone vegetation, infection by fungi of the Rhizoctonia type was predominant, vesicular-arbuscular mycorrhizal infection, which was mostly of the fine endophyte (Glomus tenuis) type, being light and mainly restricted to grasses in closed vegetation patches. More extensive Glomus tenuis infection was found in the alpine grass heath, but in Carex, Rhizoctonia was again the most important fungus. The ericaceous plants of the dwarf shrub heath have typical ericoid infection, but quantitative analysis reveals a decrease of infection intensity with increase of altitude. The possible function of the various types of root infection are discussed, and the status of Rhizoctonia as a possible mycorrhizal fungus is considered.

Classification of vegetation in an open landscape using full-waveform airborne laser scanner data

NASA Astrophysics Data System (ADS)

Alexander, Cici; Deák, Balázs; Kania, Adam; Mücke, Werner; Heilmeier, Hermann

2015-09-01

Airborne laser scanning (ALS) is increasingly being used for the mapping of vegetation, although the focus so far has been on woody vegetation, and ALS data have only rarely been used for the classification of grassland vegetation. In this study, we classified the vegetation of an open alkali landscape, characterized by two Natura 2000 habitat types: Pannonic salt steppes and salt marshes and Pannonic loess steppic grasslands. We generated 18 variables from an ALS dataset collected in the growing (leaf-on) season. Elevation is a key factor determining the patterns of vegetation types in the landscape, and hence 3 additional variables were based on a digital terrain model (DTM) generated from an ALS dataset collected in the dormant (leaf-off) season. We classified the vegetation into 24 classes based on these 21 variables, at a pixel size of 1 m. Two groups of variables with and without the DTM-based variables were used in a Random Forest classifier, to estimate the influence of elevation, on the accuracy of the classification. The resulting classes at Level 4, based on associations, were aggregated at three levels - Level 3 (11 classes), Level 2 (8 classes) and Level 1 (5 classes) - based on species pool, site conditions and structure, and the accuracies were assessed. The classes were also aggregated based on Natura 2000 habitat types to assess the accuracy of the classification, and its usefulness for the monitoring of habitat quality. The vegetation could be classified into dry grasslands, wetlands, weeds, woody species and man-made features, at Level 1, with an accuracy of 0.79 (Cohen's kappa coefficient, κ). The accuracies at Levels 2-4 and the classification based on the Natura 2000 habitat types were κ: 0.76, 0.61, 0.51 and 0.69, respectively. Levels 1 and 2 provide suitable information for nature conservationists and land managers, while Levels 3 and 4 are especially useful for ecologists, geologists and soil scientists as they provide high resolution data on species distribution, vegetation patterns, soil properties and on their correlations. Including the DTM-based variables increased the accuracy (κ) from 0.73 to 0.79 for Level 1. These findings show that the structural and spectral attributes of ALS echoes can be used for the classification of open landscapes, especially those where vegetation is influenced by elevation, such as coastal salt marshes, sand dunes, karst or alluvial areas; in these cases, ALS has a distinct advantage over other remotely sensed data.

Seasonal and diel habitat selection by bluegills in a shallow natural lake

USGS Publications Warehouse

Paukert, C.P.; Willis, D.W.

2002-01-01

Habitat use by bluegill Lepomis macrochirus may be dictated by the avoidance of predators and the availability of prey. Previous work suggests that bluegills large enough to avoid predators will select habitats based on foraging profitability. However, these studies focused on smaller fish (200 mm total length [TL]) bluegills in a shallow (mean depth = 1.2 m), 332-ha, natural lake (Pelican Lake, Nebraska) with both emergent and submergent vegetation distributed throughout. A total of 78 bluegills (200-273 mm TL) were implanted with radio transmitters and relocated daily for 6 d per month (April-September); up to 20 of the tagged fish were relocated every 2 h for a 24-h period once each month. Regardless of diel period, bluegills used open-water, emergent vegetation, submergent vegetation, and mixed emergent - submergent vegetation habitat types in similar proportions. During April, June, and July, male bluegills positively selected emergent vegetation, whereas female bluegills showed no vegetation selection preference during any month. Throughout the study period, bluegills never avoided open-water habitats, suggesting that larger individuals may continue to use open-water habitats in proportion to their availability. In addition, emergent vegetation appeared to be important, particularly for male bluegills. Although the mechanism for the positive selection of emergent vegetation by males was unclear, the protection or enhancement of such habitats may facilitate the preservation of quality bluegill populations in shallow lakes.

Semisupervised GDTW kernel-based fuzzy c-means algorithm for mapping vegetation dynamics in mining region using normalized difference vegetation index time series

NASA Astrophysics Data System (ADS)

Jia, Duo; Wang, Cangjiao; Lei, Shaogang

2018-01-01

Mapping vegetation dynamic types in mining areas is significant for revealing the mechanisms of environmental damage and for guiding ecological construction. Dynamic types of vegetation can be identified by applying interannual normalized difference vegetation index (NDVI) time series. However, phase differences and time shifts in interannual time series decrease mapping accuracy in mining regions. To overcome these problems and to increase the accuracy of mapping vegetation dynamics, an interannual Landsat time series for optimum vegetation growing status was constructed first by using the enhanced spatial and temporal adaptive reflectance fusion model algorithm. We then proposed a Markov random field optimized semisupervised Gaussian dynamic time warping kernel-based fuzzy c-means (FCM) cluster algorithm for interannual NDVI time series to map dynamic vegetation types in mining regions. The proposed algorithm has been tested in the Shengli mining region and Shendong mining region, which are typical representatives of China's open-pit and underground mining regions, respectively. Experiments show that the proposed algorithm can solve the problems of phase differences and time shifts to achieve better performance when mapping vegetation dynamic types. The overall accuracies for the Shengli and Shendong mining regions were 93.32% and 89.60%, respectively, with improvements of 7.32% and 25.84% when compared with the original semisupervised FCM algorithm.

Distribution of green open space in Malang City based on multispectral data

NASA Astrophysics Data System (ADS)

Hasyim, A. W.; Hernawan, F. P.

2017-06-01

Green open space is one of the land that its existence is quite important in urban areas where the minimum area is set to reach 30% of the total area of the city. Malang which has an area of 110,6 square kilometers, is one of the major cities in East Java Province that is prone to over-land conversion due to development needs. In support of the green space program, calculation of green space is needed precisely so that remote sensing which has high accuracy is now used for measurement of green space. This study aims to analyze the area of green open space in Malang by using Landsat 8 image in 2015. The method used was the vegetation index that is Normalized Difference Vegetation Index (NDVI). From the study obtained the calculation of green open space was better to use the vegetation index method to avoid the occurrence of misclassification of other types of land use. The results of the calculation of green open space using NDVI found that the area of green open space in Malang City in 2015 reached 39% of the total area.

Air pollution abatement performances of green infrastructure in open road and built-up street canyon environments - A review

NASA Astrophysics Data System (ADS)

Abhijith, K. V.; Kumar, Prashant; Gallagher, John; McNabola, Aonghus; Baldauf, Richard; Pilla, Francesco; Broderick, Brian; Di Sabatino, Silvana; Pulvirenti, Beatrice

2017-08-01

Intensifying the proportion of urban green infrastructure has been considered as one of the remedies for air pollution levels in cities, yet the impact of numerous vegetation types deployed in different built environments has to be fully synthesised and quantified. This review examined published literature on neighbourhood air quality modifications by green interventions. Studies were evaluated that discussed personal exposure to local sources of air pollution under the presence of vegetation in open road and built-up street canyon environments. Further, we critically evaluated the available literature to provide a better understanding of the interactions between vegetation and surrounding built-up environments and ascertain means of reducing local air pollution exposure using green infrastructure. The net effects of vegetation in each built-up environment are also summarised and possible recommendations for the future design of green infrastructure are proposed. In a street canyon environment, high-level vegetation canopies (trees) led to a deterioration in air quality, while low-level green infrastructure (hedges) improved air quality conditions. For open road conditions, wide, low porosity and tall vegetation leads to downwind pollutant reductions while gaps and high porosity vegetation could lead to no improvement or even deteriorated air quality. The review considers that generic recommendations can be provided for vegetation barriers in open road conditions. Green walls and roofs on building envelopes can also be used as effective air pollution abatement measures. The critical evaluation of the fundamental concepts and the amalgamation of key technical features of past studies by this review could assist urban planners to design and implement green infrastructures in the built environment.

Peatland Open-water Pool Biogeochemistry: The Influence of Hydrology and Vegetation

NASA Astrophysics Data System (ADS)

Arsenault, J.; Talbot, J.; Moore, T. R.

2017-12-01

Peatland open-water pools are net sources of carbon to the atmosphere. However, their interaction with the surrounding peat remains poorly known. In a previous study, we showed that shallow pools are richer in nutrients than deep pools. While depth was the main driver of biogeochemistry variations across time and space, analyses also showed that pool's adjacent vegetation may have an influence on water chemistry. Our goal is to understand the relationship between the biogeochemistry of open-water pools and their surroundings in a subboreal ombrotrophic peatland of southern Quebec (Canada). To assess the influence of vegetation on pool water chemistry, we compare two areas covered with different types of vegetation: a forested zone dominated by spruce trees and an open area mostly covered by Sphagnum spp. To evaluate the direction of water (in or out of the pools), we installed capacitance water level probes in transects linking pools in the two zones. Wells were also installed next to each probe to collect peat pore water samples. Samples were taken every month during summer 2017 and analyzed for dissolved organic carbon, nitrogen and phosphorus, pH and specific UV absorbance. Preliminary results show differences in peat water chemistry depending on the dominant vegetation. In both zones, water levels fluctuations are disconnected between peat and the pools, suggesting poor horizontal water movement. Pool water chemistry may be mostly influenced by the immediate surrounding vegetation than by the local vegetation pattern. Climate and land-use change may affect the vegetation structure of peatlands, thus affecting pool biogeochemistry. Considering the impact of pools on the overall peatland capacity to accumulate carbon, our results show that more focus must be placed on pools to better understand peatland stability over time.

Effect of Land Cover Type and Structure on Water Cycling Dynamics for Agricultural and Wetland Sites in the Sacramento/San Joaquin River Delta

NASA Astrophysics Data System (ADS)

Eichelmann, E.; Hemes, K. S.; Baldocchi, D. D.

2016-12-01

The Sacramento/San Joaquin river delta is an important source of fresh water for California. To reverse soil subsidence, which is linked to draining the natural wetlands for agriculture, parts of the Sacramento/San Joaquin river delta have been restored to managed wetlands. While these restored wetlands provide greenhouse gas benefits compared to agricultural use of the land, implications for the water balance of these ecosystems, specifically evapotranspiration, are not well known. Based on multiple years of eddy covariance measurements of water, CO2, and sensible energy fluxes we explored the water cycling dynamics for several sites under different land use covers in the Sacramento/San Joaquin river delta. We investigated four sites under agricultural use (rice, corn, and alfalfa crops and cow pasture) and three restored wetland sites of varying ages and structures to examine the influence of land cover type and structure on evapotranspiration, sensible energy flux, and water use efficiency. While the wetland and the rice sites are usually flooded for the majority of the year, the alfalfa, corn, and pasture sites have a water table that is maintained to be below ground level throughout the year. The three wetland sites also have different fractions of open water to vegetation, covering a gradient from very dense vegetation with no open water to a fairly open structure with large pools of open water. These differences in land cover (dry vs flooded and fraction of open water to vegetation) have an effect on the patterns of evapotranspiration on diurnal to annual timescales. Although the flooded sites (wetland sites and rice) tend to have larger annual evapotranspiration than the drained sites (cow pasture, alfalfa, and corn), the fraction of open water to vegetation affects the extend to which the flooded sites' evapotranspiration exceeds that of drained sites. On diurnal timescales, we found that flooded sites with a larger fraction of open water to vegetation have larger night time latent energy fluxes, especially during the first half of the night. In contrast, flooded sites with a lower open water fraction have lower night time latent energy fluxes which are comparable in magnitude to night time fluxes at drained sites.

Gasification: An alternative solution for energy recovery and utilization of vegetable market waste.

PubMed

Narnaware, Sunil L; Srivastava, Nsl; Vahora, Samir

2017-03-01

Vegetables waste is generally utilized through a bioconversion process or disposed of at municipal landfills, dumping sites or dumped on open land, emitting a foul odor and causing health hazards. The presents study deals with an alternative way to utilize solid vegetable waste through a thermochemical route such as briquetting and gasification for its energy recovery and subsequent power generation. Briquettes of 50 mm diameter were produced from four different types of vegetable waste. The bulk density of briquettes produced was increased 10 to 15 times higher than the density of the dried vegetable waste in loose form. The lower heating value (LHV) of the briquettes ranged from 10.26 MJ kg -1 to 16.60 MJ kg -1 depending on the type of vegetable waste. The gasification of the briquettes was carried out in an open core downdraft gasifier, which resulted in syngas with a calorific value of 4.71 MJ Nm -3 at the gasification temperature between 889°C and 1011°C. A spark ignition, internal combustion engine was run on syngas and could generate a maximum load up to 10 kW e . The cold gas efficiency and the hot gas efficiency of the gasifier were measured at 74.11% and 79.87%, respectively. Energy recovery from the organic vegetable waste was possible through a thermochemical conversion route such as briquetting and subsequent gasification and recovery of the fuel for small-scale power generation.

National Park Service Vegetation Inventory Program, Cuyahoga Valley National Park, Ohio

USGS Publications Warehouse

Hop, Kevin D.; Drake, J.; Strassman, Andrew C.; Hoy, Erin E.; Menard, Shannon; Jakusz, J.W.; Dieck, J.J.

2013-01-01

The National Park Service (NPS) Vegetation Inventory Program (VIP) is an effort to classify, describe, and map existing vegetation of national park units for the NPS Natural Resource Inventory and Monitoring (I&M) Program. The NPS VIP is managed by the NPS Biological Resources Management Division and provides baseline vegetation information to the NPS Natural Resource I&M Program. The U.S. Geological Survey (USGS) Vegetation Characterization Program lends a cooperative role in the NPS VIP. The USGS Upper Midwest Environmental Sciences Center, NatureServe, and NPS Cuyahoga Valley National Park (CUVA) have completed vegetation classification and mapping of CUVA.Mappers, ecologists, and botanists collaborated to identify and describe vegetation types within the National Vegetation Classification Standard (NVCS) and to determine how best to map them by using aerial imagery. The team collected data from 221 vegetation plots within CUVA to develop detailed descriptions of vegetation types. Data from 50 verification sites were also collected to test both the key to vegetation types and the application of vegetation types to a sample set of map polygons. Furthermore, data from 647 accuracy assessment (AA) sites were collected (of which 643 were used to test accuracy of the vegetation map layer). These data sets led to the identification of 45 vegetation types at the association level in the NVCS at CUVA.A total of 44 map classes were developed to map the vegetation and general land cover of CUVA, including the following: 29 map classes represent natural/semi-natural vegetation types in the NVCS, 12 map classes represent cultural vegetation (agricultural and developed) in the NVCS, and 3 map classes represent non-vegetation features (open-water bodies). Features were interpreted from viewing color-infrared digital aerial imagery dated October 2010 (during peak leaf-phenology change of trees) via digital onscreen three-dimensional stereoscopic workflow systems in geographic information systems (GIS). The interpreted data were digitally and spatially referenced, thus making the spatial database layers usable in GIS. Polygon units were mapped to either a 0.5 ha or 0.25 ha minimum mapping unit, depending on vegetation type.A geodatabase containing various feature-class layers and tables shows the locations of vegetation types and general land cover (vegetation map), vegetation plot samples, verification sites, AA sites, project boundary extent, and aerial photographic centers. The feature-class layer and relate tables for the CUVA vegetation map provides 4,640 polygons of detailed attribute data covering 13,288.4 ha, with an average polygon size of 2.9 ha.Summary reports generated from the vegetation map layer show map classes representing natural/semi-natural types in the NVCS apply to 4,151 polygons (89.4% of polygons) and cover 11,225.0 ha (84.5%) of the map extent. Of these polygons, the map layer shows CUVA to be 74.4% forest (9,888.8 ha), 2.5% shrubland (329.7 ha), and 7.6% herbaceous vegetation cover (1,006.5 ha). Map classes representing cultural types in the NVCS apply to 435 polygons (9.4% of polygons) and cover 1,825.7 ha (13.7%) of the map extent. Map classes representing non-NVCS units (open water) apply to 54 polygons (1.2% of polygons) and cover 237.7 ha (1.8%) of the map extent.A thematic AA study was conducted of map classes representing natural/semi-natural types in the NVCS. Results present an overall accuracy of 80.7% (kappa index of 79.5%) based on data from 643 of the 647 AA sites. Most individual map-class themes exceed the NPS VIP standard of 80% with a 90% confidence interval.The CUVA vegetation mapping project delivers many geospatial and vegetation data products in hardcopy and/or digital formats. These products consist of an in-depth project report discussing methods and results, which include descriptions and a dichotomous key to vegetation types, map classification and map-class descriptions, and a contingency table showing AA results. The suite of products also includes a database of vegetation plots, verification sites, and AA sites; digital pictures of field sites; field data sheets; aerial photographic imagery; hardcopy and digital maps; and a geodatabase of vegetation types and land cover (map layer), fieldwork locations (vegetation plots, verification sites, and AA sites), aerial photographic index, project boundary, and metadata. All geospatial products are projected in Universal Transverse Mercator, Zone 17, by using the North American Datum of 1983. Information on the NPS VIP and completed park mapping projects are located on the Internet at and .

National Park Service Vegetation Mapping Inventory Program: Natchez Trace Parkway vegetation mapping project report

USGS Publications Warehouse

Hop, Kevin D.; Strassman, Andrew C.; Nordman, Carl; Pyne, Milo; White, Rickie; Jakusz, Joseph; Hoy, Erin E.; Dieck, Jennifer

2016-01-01

The National Park Service (NPS) Vegetation Mapping Inventory (VMI) Program is an effort to classify, describe, and map existing vegetation of national park units for the NPS Natural Resource Inventory and Monitoring (I&M) Program. The NPS VMI Program is managed by the NPS I&M Division and provides baseline vegetation information to the NPS Natural Resource I&M Program. The U.S. Geological Survey Upper Midwest Environmental Sciences Center, NatureServe, NPS Gulf Coast Network, and NPS Natchez Trace Parkway (NATR; also referred to as Parkway) have completed vegetation classification and mapping of NATR for the NPS VMI Program.Mappers, ecologists, and botanists collaborated to affirm vegetation types within the U.S. National Vegetation Classification (USNVC) of NATR and to determine how best to map them by using aerial imagery. Analyses of data from 589 vegetation plots had been used to describe an initial 99 USNVC associations in the Parkway; this classification work was completed prior to beginning this NATR vegetation mapping project. Data were collected during this project from another eight quick plots to support new vegetation types not previously identified at the Parkway. Data from 120 verification sites were collected to test the field key to vegetation associations and the application of vegetation associations to a sample set of map polygons. Furthermore, data from 900 accuracy assessment (AA) sites were collected (of which 894 were used to test accuracy of the vegetation map layer). The collective of all these datasets resulted in affirming 122 USNVC associations at NATR.To map the vegetation and open water of NATR, 63 map classes were developed. including the following: 54 map classes represent natural (including ruderal) vegetation types in the USNVC, 5 map classes represent cultural (agricultural and developed) vegetation types in the USNVC, 3 map classes represent nonvegetation open-water bodies (non-USNVC), and 1 map class represents landscapes that had received tornado damage a few months prior to the time of aerial imagery collection. Features were interpreted from viewing 4-band digital aerial imagery by means of digital onscreen three-dimensional stereoscopic workflow systems in geographic information systems. (The aerial imagery was collected during mid-October 2011 for the northern reach of the Parkway and mid-November 2011 for the southern reach of the Parkway to capture peak leaf-phenology of trees.) The interpreted data were digitally and spatially referenced, thus making the spatial-database layers usable in geographic information systems. Polygon units were mapped to either a 0.5 hectare (ha) or 0.25 ha minimum mapping unit, depending on vegetation type or scenario.A geodatabase containing various feature-class layers and tables present the locations of USNVC vegetation types (vegetation map), vegetation plot samples, verification sites, AA sites, project boundary extent, and aerial image centers. The feature-class layer and related tables for the vegetation map provide 13,529 polygons of detailed attribute data covering 21,655.5 ha, with an average polygon size of 1.6 ha; the vegetation map coincides closely with the administrative boundary for NATR.Summary reports generated from the vegetation map layer of the map classes representing USNVC natural (including ruderal) vegetation types apply to 12,648 polygons (93.5% of polygons) and cover 18,542.7 ha (85.6%) of the map extent for NATR. The map layer indicates the Parkway to be 70.5% forest and woodland (15,258.7 ha), 0.3% shrubland (63.0 ha), and 14.9% herbaceous cover (3,221.0 ha). Map classes representing USNVC cultural types apply to 678 polygons (5.0% of polygons) and cover 2,413.9 ha (11.1%) of the map extent.

Estimating forest-grassland dynamics using soil phytolith assemblages and δ13C of soil organic matter

Treesearch

Becky K. Kerns; Margeret M. Moore; Stephen C. Hart

2001-01-01

Our objectives were to examine the relationship between contemporary vegetation and surface soil phytolith assemblages, and use phytoliths and δ13C of soil organic matter (SOM) to explore forest-grassland vegetation dynamics. We established plots within three canopy types (open, old-growth, and dense young pine) with different grass species compositions in a...

Plantings for wildlife

Treesearch

Samuel B. Kirby; Claude L. Ponder; Donald J. Smith

1989-01-01

Grains, forages, and other vegetation can be planted to provide critical habitat for desired wildlife species or to increase habitat diversity. Plantings may be in openings created in the forest (see Note 9.11 Wildlife Openings) or along the forest edge in cultivated or pastured fields if protected from domestic livestock. The first step in determining if and what type...

Greenhouse cultivation mitigates metal-ingestion-associated health risks from vegetables in wastewater-irrigated agroecosystems.

PubMed

Cao, Chun; Chen, Xing-Peng; Ma, Zhen-Bang; Jia, Hui-Hui; Wang, Jun-Jian

2016-08-01

Wastewater irrigation can elevate metal concentrations in soils and crops and increase the metal-associated health risks via vegetable ingestion in arid and semiarid northwestern China. Here, we investigated the As, Cd, Cr, Cu, Ni, Pb, and Zn concentrations in four vegetable species from Dongdagou and Xidagou farmlands in Baiyin, Gansu, China. We evaluated the effects of irrigation type (Dongdagou: industrial wastewater; Xidagou: domestic wastewater) and cultivation mode (open field and greenhouse) on the vegetable metal concentration, metal partitioning, soil-to-plant bioconcentration factor (BCF), and the health risk index. All stream waters, soils, and vegetables were found most severely polluted by As and Cd, with higher severity in the industrial-wastewater-irrigated Dongdagou than the domestic-wastewater-irrigated Xidagou. All vegetables had higher or, at least, comparable metal mass allocated in the shoot than in the root. Greenhouse cultivation could reduce metal-ingestion-associated health risks from edible vegetable biomass by decreasing the soil to plant bioaccumulation (BCF) and the metal concentration. This effect was always significant for all vegetables within Xidagou, and for carrot within Dongdagou. This mitigation effect of greenhouse cultivation could be attributed to the metal sorption by a higher level of soil organic matter and faster growth rate over metal uptake rate in greenhouses compared to open fields. Such mitigation effect was, however, insignificant for leafy vegetables within Dongdagou, when much more severely polluted water for irrigation was applied in greenhouses compared to open fields within Dongdagou. The present study highlights greenhouse cultivation as a potential mitigating approach to providing less-polluted vegetables for residents in the severely polluted area in addition to the source pollution control. Copyright © 2016 Elsevier B.V. All rights reserved.

Global hierarchical classification of deepwater and wetland environments from remote sensing products

NASA Astrophysics Data System (ADS)

Fluet-Chouinard, E.; Lehner, B.; Aires, F.; Prigent, C.; McIntyre, P. B.

2017-12-01

Global surface water maps have improved in spatial and temporal resolutions through various remote sensing methods: open water extents with compiled Landsat archives and inundation with topographically downscaled multi-sensor retrievals. These time-series capture variations through time of open water and inundation without discriminating between hydrographic features (e.g. lakes, reservoirs, river channels and wetland types) as other databases have done as static representation. Available data sources present the opportunity to generate a comprehensive map and typology of aquatic environments (deepwater and wetlands) that improves on earlier digitized inventories and maps. The challenge of classifying surface waters globally is to distinguishing wetland types with meaningful characteristics or proxies (hydrology, water chemistry, soils, vegetation) while accommodating limitations of remote sensing data. We present a new wetland classification scheme designed for global application and produce a map of aquatic ecosystem types globally using state-of-the-art remote sensing products. Our classification scheme combines open water extent and expands it with downscaled multi-sensor inundation data to capture the maximal vegetated wetland extent. The hierarchical structure of the classification is modified from the Cowardin Systems (1979) developed for the USA. The first level classification is based on a combination of landscape positions and water source (e.g. lacustrine, riverine, palustrine, coastal and artificial) while the second level represents the hydrologic regime (e.g. perennial, seasonal, intermittent and waterlogged). Class-specific descriptors can further detail the wetland types with soils and vegetation cover. Our globally consistent nomenclature and top-down mapping allows for direct comparison across biogeographic regions, to upscale biogeochemical fluxes as well as other landscape level functions.

Assessment of heterogeneity in types of vegetables served by main household food preparers and food decision influencers.

PubMed

Yi, Sunghwan; Kanetkar, Vinay; Brauer, Paula

2015-10-01

While vegetables are often studied as one food group, global measures may mask variation in the types and forms of vegetables preferred by different individuals. To explore preferences for and perceptions of vegetables, we assessed main food preparers based on their preparation of eight specific vegetables and mushrooms. An online self-report survey. Ontario, Canada. Measures included perceived benefits and obstacles of vegetables, convenience orientation and variety seeking in meal preparation. Of the 4517 randomly selected consumers who received the invitation, 1013 responded to the survey (22·4 % response). Data from the main food preparers were analysed (n 756). Latent profile analysis indicated three segments of food preparers. More open to new recipes, the 'crucifer lover' segment (13 %) prepared and consumed substantially more Brussels sprouts, broccoli and asparagus than the other segments. Although similar to the 'average consumer' segment (54 %) in many ways, the 'frozen vegetable user' segment (33 %) used significantly more frozen vegetables than the other segments due to higher prioritization of time and convenience in meal preparation and stronger 'healthy=not tasty' perception. Perception of specific vegetables on taste, healthiness, ease of preparation and cost varied significantly across the three consumer segments. Crucifer lovers also differed with respect to shopping and cooking habits compared with the frozen vegetable users. The substantial heterogeneity in the types of vegetables consumed and perceptions across the three consumer segments has implications for the development of new approaches to promoting these foods.

Parasitic contamination of fresh vegetables sold at central markets in Khartoum state, Sudan.

PubMed

Mohamed, Mona Ali; Siddig, Emmanuel Edwar; Elaagip, Arwa Hassan; Edris, Ali Mahmoud Mohammed; Nasr, Awad Ahmed

2016-03-11

Fresh vegetables are considered as vital nutrients of a healthy diet as they supply the body with essential supplements. The consumption of raw vegetables is the main way for transmission of intestinal parasitic organisms. This study was aimed at detecting the parasitic contamination in fresh vegetables sold in two central open-aired markets in Khartoum state, Sudan. In this prospective cross-sectional study, a total of 260 fresh vegetable samples and 50 water samples used to sprinkle vegetable(s) were collected from two central open-aired markets (namely; Elshaabi and Central markets) during November 2011 to May 2012. The samples were microscopically examined for detection of parasitic life forms using standardized parasitological techniques for protozoans and helminthes worms. Of the 260 fresh vegetable samples, 35 (13.5 %) were microscopically positive for intestinal parasites whereas 7/50 (14 %) of water samples used to sprinkle vegetable(s) were found positives. Remarkably, high level of contamination in fresh vegetable samples was recorded in lettuce (Lactuca sativa) 36.4 % (4/11) while cayenne pepper (Capsicum annuum) and cucumber (Cucumis sativus) were not contaminated. The identified protozoans and helminthes were Entamoeba histolytica/dispar, Entamoeba coli, Giardia lamblia, Ascaris lumbricoides, Strongyloides stercoralis, T. trichiura and hookworms. The most predominant parasite encountered was E. histolytica/dispar (42.9 %) whereas both T. trichiura and A. lumbricoides (2.9 %) were the least detected parasites. None of the fresh vegetables had single parasitic contamination. The highest percentages found in water samples used to sprinkle vegetable(s) was for Strongyloides larvae 60 % (3/5). It is worth-mentioned that the rate of contamination in Elshaabi market was higher compared with Central market. However, there was no significant correlation between the type of vegetables and existence of parasites in both markets and a high significant relationship was observed between the type of parasite and total prevalence in fresh vegetables (p = 0.000). The study has identified a moderate rate of fresh vegetables contaminated with protozoan and helminthes. Contaminated fresh vegetables in central markets of Khartoum state may play a significant role in transmission of intestinal parasitic infections to humans, and the water used by greengrocers to sprinkle vegetable(s) can be implicated in vegetable contamination.

The role of urban forest to reduce rain acid in urban industrial areas

NASA Astrophysics Data System (ADS)

Slamet, B.; Agustiarni, Y.; Hidayati; Basyuni, M.

2018-03-01

Urban forest has many functions mainly on improving the quality of the urban environment. One of the functions is to increase pH and reduce dangerous chemical content. The aim of the research is to find out the role of vegetation density of urban forest around the industrial area in reducing the acid rain. The condition of land cover was classified into four classes which are dense, medium, sparse and open area. The water of the throughfall and stemflow was taken from each type of land cover except in the open area. Parameters measured in this study are water acidity (pH), anion content (SO4 2- and NO3 -), cation content (Ca2+, Mg2+, and NH4 +) and electrical conductivity (EC). The results indicated that urban forest vegetation was able to increase the pH of rain water from 5.42 which is in an open area without vegetation to be 7.13 and 7.32 in dense and moderate vegetation cover by throughfall mechanism, respectively. Rain water acidity also decreased through stemflow mechanism with a pH ranged from 5.92 - 6.43. Urban forest vegetation decreased sulfate content (SO42-) from 528.67 mg/l in open area to 44 - 118 mg/l by throughfall mechanism and ranged from 90 to 366.67 mg/l through stemflow mechanism. Urban forest vegetation significantly decreased the rainwater nitrate content from 27 mg/l to 0.03 - 0.70 mg/l through the mechanism of throughfall and between 1.53 - 8.82 mg/l through the stemflow mechanism. Urban forest vegetation also increased the concentration of cations (NH4+, Ca2+, Mg2+, Na+) compared with open areas. Urban forest vegetation showed increased the electrical conductivity (EC) from 208.12 μmhos/cm to 344.67 - 902.17 μmhos/cm through the through fall mechanism and 937.67 - 1058.70 μmhos/cm through the stemflow mechanism. The study suggested that urban forests play a significant role in reducing rainwater acidity and improving the quality of rainwater that reached the soil surface.

The Use of Sun Elevation Angle for Stereogrammetric Boreal Forest Height in Open Canopies

NASA Technical Reports Server (NTRS)

Montesano, Paul M.; Neigh, Christopher; Sun, Guoqing; Duncanson, Laura Innice; Van Den Hoek, Jamon; Ranson, Kenneth Jon

2017-01-01

Stereogrammetry applied to globally available high resolution spaceborne imagery (HRSI; less than 5 m spatial resolution) yields fine-scaled digital surface models (DSMs) of elevation. These DSMs may represent elevations that range from the ground to the vegetation canopy surface, are produced from stereoscopic image pairs (stereo pairs) that have a variety of acquisition characteristics, and have been coupled with lidar data of forest structure and ground surface elevation to examine forest height. This work explores surface elevations from HRSI DSMs derived from two types of acquisitions in open canopy forests. We (1) apply an automated mass-production stereogrammetry workflow to along-track HRSI stereo pairs, (2) identify multiple spatially coincident DSMs whose stereo pairs were acquired under different solar geometry, (3) vertically co-register these DSMs using coincident spaceborne lidar footprints (from ICESat-GLAS) as reference, and(4) examine differences in surface elevations between the reference lidar and the co-registered HRSI DSMs associated with two general types of acquisitions (DSM types) from different sun elevation angles. We find that these DSM types, distinguished by sun elevation angle at the time of stereo pair acquisition, are associated with different surface elevations estimated from automated stereogrammetry in open canopy forests. For DSM values with corresponding reference ground surface elevation from spaceborne lidar footprints in open canopy northern Siberian Larix forests with slopes less than10, our results show that HRSI DSM acquired with sun elevation angles greater than 35deg and less than 25deg (during snow-free conditions) produced characteristic and consistently distinct distributions of elevation differences from reference lidar. The former include DSMs of near-ground surfaces with root mean square errors less than 0.68 m relative to lidar. The latter, particularly those with angles less than 10deg, show distributions with larger differences from lidar that are associated with open canopy forests whose vegetation surface elevations are captured. Terrain aspect did not have a strong effect on the distribution of vegetation surfaces. Using the two DSM types together, the distribution of DSM-differenced heights in forests (6.0 m, sigma = 1.4 m) was consistent with the distribution of plot-level mean tree heights (6.5m, sigma = 1.2 m). We conclude that the variation in sun elevation angle at time of stereo pair acquisition can create illumination conditions conducive for capturing elevations of surfaces either near the ground or associated with vegetation canopy. Knowledge of HRSI acquisition solar geometry and snow cover can be used to understand and combine stereogrammetric surface elevation estimates to co-register rand difference overlapping DSMs, providing a means to map forest height at fine scales, resolving the vertical structure of groups of trees from spaceborne platforms in open canopy forests.

GIS-Based Noise Simulation Open Source Software: N-GNOIS

NASA Astrophysics Data System (ADS)

Vijay, Ritesh; Sharma, A.; Kumar, M.; Shende, V.; Chakrabarti, T.; Gupta, Rajesh

2015-12-01

Geographical information system (GIS)-based noise simulation software (N-GNOIS) has been developed to simulate the noise scenario due to point and mobile sources considering the impact of geographical features and meteorological parameters. These have been addressed in the software through attenuation modules of atmosphere, vegetation and barrier. N-GNOIS is a user friendly, platform-independent and open geospatial consortia (OGC) compliant software. It has been developed using open source technology (QGIS) and open source language (Python). N-GNOIS has unique features like cumulative impact of point and mobile sources, building structure and honking due to traffic. Honking is the most common phenomenon in developing countries and is frequently observed on any type of roads. N-GNOIS also helps in designing physical barrier and vegetation cover to check the propagation of noise and acts as a decision making tool for planning and management of noise component in environmental impact assessment (EIA) studies.

Legume Diversity Patterns in West Central Africa: Influence of Species Biology on Distribution Models

PubMed Central

de la Estrella, Manuel; Mateo, Rubén G.; Wieringa, Jan J.; Mackinder, Barbara; Muñoz, Jesús

2012-01-01

Objectives Species Distribution Models (SDMs) are used to produce predictions of potential Leguminosae diversity in West Central Africa. Those predictions are evaluated subsequently using expert opinion. The established methodology of combining all SDMs is refined to assess species diversity within five defined vegetation types. Potential species diversity is thus predicted for each vegetation type respectively. The primary aim of the new methodology is to define, in more detail, areas of species richness for conservation planning. Methodology Using Maxent, SDMs based on a suite of 14 environmental predictors were generated for 185 West Central African Leguminosae species, each categorised according to one of five vegetation types: Afromontane, coastal, non-flooded forest, open formations, or riverine forest. The relative contribution of each environmental variable was compared between different vegetation types using a nonparametric Kruskal-Wallis analysis followed by a post-hoc Kruskal-Wallis Paired Comparison contrast. Legume species diversity patterns were explored initially using the typical method of stacking all SDMs. Subsequently, five different ensemble models were generated by partitioning SDMs according to vegetation category. Ecological modelers worked with legume specialists to improve data integrity and integrate expert opinion in the interpretation of individual species models and potential species richness predictions for different vegetation types. Results/Conclusions Of the 14 environmental predictors used, five showed no difference in their relative contribution to the different vegetation models. Of the nine discriminating variables, the majority were related to temperature variation. The set of variables that played a major role in the Afromontane species diversity model differed significantly from the sets of variables of greatest relative important in other vegetation categories. The traditional approach of stacking all SDMs indicated overall centers of diversity in the region but the maps indicating potential species richness by vegetation type offered more detailed information on which conservation efforts can be focused. PMID:22911808

Prevalence of foodborne pathogens in retailed foods in Thailand.

PubMed

Ananchaipattana, Chiraporn; Hosotani, Yukie; Kawasaki, Susumu; Pongsawat, Sirikae; Latiful, Bari Md; Isobe, Seiichiro; Inatsu, Yasuhiro

2012-09-01

The consumption of foodborne pathogens contaminated in food is one of the major causes of diarrheal diseases in Thailand. The objective of this study was to evaluate the prevalence and types of contaminating bacteria in retailed foodstuffs in Thailand. Food from four categories (137 samples total), including meat (51 samples), vegetables (38 samples), fish or seafood (37 samples), and fermented food (11 samples), was purchased randomly from seven different open-markets and seven supermarkets in Thailand from August 2010 to March 2011. Seven types of major foodborne pathogens were identified using conventional culture methods. Approximately 80% of meat samples tested was contaminated with Salmonella spp. In contrast, the Salmonella spp. contamination rate of vegetable (5%) or fermented food (9%) samples was comparatively low. Six strains of Cronobacter sakazakii and two strains of Yersinia enterocolitica were also isolated. A substantially higher rate of contamination by Bacillus cereus was observed in fermented food (82%) than in samples of meat (2%) and fish or seafood (5%). Seven Listeria spp. isolates were obtained from meat and fish or seafood samples. Approximately 39% of samples tested were found to be contaminated with Staphylococcus spp. (54 isolates). The rate of bacterial contamination of meat did not depend on the type of market. However, the contamination rate of Staphylococcus spp. in vegetables was higher in open markets than in supermarkets, and the contamination rate of Salmonella spp. and Staphylococcus spp. in fish or seafood samples purchased in open markets was likewise higher than in those purchased in supermarkets. Therefore, improvement of hygienic practices throughout the food chain may be required to reduce the risk of food poisoning.

Effects of Re-vegetation on Herbaceous Species Composition and Biological Soil Crusts Development in a Coal Mine Dumping Site

NASA Astrophysics Data System (ADS)

Zhao, Yang; Zhang, Peng; Hu, Yigang; Huang, Lei

2016-02-01

Despite the critical roles of plant species' diversity and biological soil crusts (BSCs) in arid and semi-arid ecosystems, the restoration of the diversity of herbaceous species and BSCs are rarely discussed during the process of vegetation restoration of anthropogenically damaged areas in these regions. In this study, the herbaceous plant species composition, along with the BSCs coverage and thicknesses, was investigated at six different re-vegetation type sites, and the natural vegetation site of the Heidaigou open pit coal mine in China's Inner Mongolia Autonomous Region was used as a reference. The highest total species richness (16), as well as the species richness (4.4), occurred in the Tree and Herbaceous vegetation type site. The species composition similarities between the restored sites and the reference site were shown to be very low, and ranged from 0.09 to 0.42. Also, among the restored sites, the similarities of the species were fairly high and similar, and ranged from 0.45 to 0.93. The density and height of the re-vegetated woody plants were significantly correlated with the indexes of the diversity of the species. The Shrub vegetation type site showed the greatest total coverage (80 %) of BSCs and algae crust coverage (48 %). The Shrub and Herbaceous type had the greatest thicknesses of BSCs, with as much as 3.06 mm observed, which was followed by 2.64 mm for the Shrub type. There was a significant correlation observed between the coverage of the total BSCs, and the total vegetation and herbaceous vegetation coverage, as well as between the algae crust coverage and the herbaceous vegetation coverage. It has been suggested that the re-vegetated dwarf woody plant species (such as shrubs and semi-shrubs) should be chosen for the optimal methods of the restoration of herbaceous species diversity at dumping sites, and these should be planted with low density. Furthermore, the effects of vegetation coverage on the colonization and development the BSCs should be considered in order to reconstruct the vegetation in disturbed environments, such as mine dumpsites in arid areas.

Capacity and degree of iodine absorbed and enriched by vegetable from soil.

PubMed

Weng, Huan-Xin; Weng, Jing-Ke; Yong, Wen-Bin; Sun, Xiang-Wu; Zhong, Hang

2003-01-01

To understand the biogeochemical transfer of iodine, the absorbability and bioaccumulation of iodine in tested vegetables (radish, spinach and Chinese cabbage) are examined by applying iodic fertilizer composed of kelp and diatomaceous earth. The experimental results show that when iodine in soil is not excessive, the concentrations of iodine in tested vegetables increase as the content of iodine in soil increases. The absorbability and enrichment degree of iodine in various vegetables and in various parts of the same vegetable a redifferent, which explains that the concentration of iodine in plant is determined by the plant type and the physiological action of plant. The patience order of tested vegetables to excessive iodine is Chinese cabbage > spinach > radish. These results have theoretical and practical significance in opening up a new way for ameliorating poor iodine environment with artificial means.

Evaluation of open source data mining software packages

Treesearch

Bonnie Ruefenacht; Greg Liknes; Andrew J. Lister; Haans Fisk; Dan Wendt

2009-01-01

Since 2001, the USDA Forest Service (USFS) has used classification and regression-tree technology to map USFS Forest Inventory and Analysis (FIA) biomass, forest type, forest type groups, and National Forest vegetation. This prior work used Cubist/See5 software for the analyses. The objective of this project, sponsored by the Remote Sensing Steering Committee (RSSC),...

Divergent Impacts of Two Cattle Types on Vegetation in Coastal Meadows: Implications for Management

NASA Astrophysics Data System (ADS)

Laurila, Marika; Huuskonen, Arto; Pesonen, Maiju; Kaseva, Janne; Joki-Tokola, Erkki; Hyvärinen, Marko

2015-11-01

The proportion of beef cattle in relation to the total number of cattle has increased in Europe, which has led to a higher contribution of beef cattle in the management of semi-natural grasslands. Changes in vegetation caused by this change in grazers are virtually unexplored so far. In the present study, the impacts of beef and dairy cattle on vegetation structure and composition were compared on Bothnian Bay coastal meadows. Vegetation parameters were measured in seven beef cattle, six dairy heifer pastures, and in six unmanaged meadows. Compared to unmanaged meadows, vegetation in grazed meadows was significantly lower in height and more frequently colonized by low-growth species. As expected, vegetation grazed by beef cattle was more open than that on dairy heifer pastures where litter cover and proportion of bare ground were in the same level as in the unmanaged meadows. However, the observed differences may have in part arisen from the higher cattle densities in coastal meadows grazed by beef cattle than by dairy heifers. The frequencies of different species groups and the species richness values of vegetation did not differ between the coastal meadows grazed by the two cattle types. One reason for this may be the relatively short management history of the studied pastures. The potential differences in grazing impacts of the two cattle types on vegetation structure can be utilized in the management of coastal meadows for species with divergent habitat requirements.

[Comparison of soil fertility among open-pit mine reclaimed lands in Antaibao regenerated with different vegetation types].

PubMed

Wang, Xiang; Li, Jin-chuan; Yue, Jian-ying; Zhou, Xiao-mei; Guo, Chun-yan; Lu, Ning; Wang, Yu-hong; Yang, Sheng-quan

2013-09-01

Re-vegetation is mainly applied into regeneration in opencast mine to improve the soil quality. It is very important to choose feasible vegetation types for soil restoration. In this study, three typical forest restoration types were studied at Antaibao mine, namely, Medicago sativa, mixed forests Pinus taebelaefolius-Robinia pseudoacacia-Caragana korshinskii and Elaeagnus angustifolia-Robinia pseudoacacia-Caragana korshinskii-Hipophae rhamnoides, to determine the nutrient contents and enzyme activities in different soil layers. The results showed that re-vegetation markedly increased soil nutrient contents and the enzyme activities during the restoration process. The nutrient content of soil in the P. taebelaefolius-R. pseudoacacia-C. korshinskii mixed forest field was significantly higher than those in other plots. It was found that the soil of the P. taebelaefolius-R. pseudoacacia-C. korshinskii mixed forest had the highest integrated fertility index values. In conclusion, the restoration effects of the P. zaebelaefolius-R. pseudoacacia-C. Korshinskii mixed forest was better than that of E. angustifolia-R. pseudoacacia-C. korshinskii-H. rhamnoides, while M. sativa grassland had the least effect.

Wave Velocity Attenuation and Sediment Retention among Different Vegetation Types in a Pacific Northwest Estuary

NASA Astrophysics Data System (ADS)

Lemein, T.; Cox, D. T.; Albert, D.; Blackmar, P.

2012-12-01

Feedbacks between vegetation, wave climate, and sedimentation create stable ecosystem states within estuaries that provide ecosystem services such as wildlife habitat, erosion control, and pollution filtration. Flume and field studies conducted with cordgrass (Spartina spp.) and sea grasses (Zostera spp., Halodule spp.) have demonstrated that the presence of vegetation reduces wave energy and increases sediment retention. Since the spatial distribution of plant species and the presence of unique plant species differ between estuaries, there is a need to understand how individual plant species, or groups of species with similar morphology, influence wave characteristics and sedimentation. Within Tillamook Bay, Oregon, three species of emergent vascular vegetation species (Carex lyngbyei, Eleocharis sp., Schoenoplectus pungens) and one species of submergent vascular vegetation species (Zostera marina) are present in the high wave energy portion of the estuary at the border of open water and the start of vegetation. These species represent three distinct growth forms (emergent reeds, emergent grasses, submergent grasses) and occur at varying densities relative to each other, as well as within the estuary. Using paired acoustic Doppler velocimeters (ADVs), we quantify the relative attenuation of wave velocity between vegetation types and densities within the estuary and compare these results with published attenuation rates from flume and field studies in different environments. The effect of decreased wave velocity on sediment retention is measured using permanent sediment markers within and outside of vegetation stands and paired with ADV data. Sediment retention is predicted to vary seasonally with seasonal vegetation composition changes and remain constant in unvegetated areas. From this experiment we expect to identify like groups of plant species whose attenuation characteristics are the same, allowing for models of wave-vegetation-sediment interaction to be created with multiple vegetation types.

Recent shifts in Himalayan vegetation activity trends in response to climatic change and environmental drivers

NASA Astrophysics Data System (ADS)

Mishra, N. B.; Mainali, K. P.

2016-12-01

Climatic changes along with anthropogenic disturbances are causing dramatic ecological impacts in mid to high latitude mountain vegetation including in the Himalayas which are ecologically sensitive environments. Given the challenges associated with in situ vegetation monitoring in the Himalayas, remote sensing based quantification of vegetation dynamics can provide essential ecological information on changes in vegetation activity that may consist of alternative sequence of greening and/or browning periods. This study utilized a trend break analysis procedure for detection of monotonic as well as abrupt (either interruption or reversal) trend changes in smoothed normalized difference vegetation index satellite time-series data over the Himalayas. Overall, trend breaks in vegetation greenness showed high spatio-temporal variability in distribution considering elevation, ecoregion and land cover/use stratifications. Interrupted greening was spatially most dominant in all Himalayan ecoregions followed by abrupt browning. Areas showing trend reversal and monotonic trends appeared minority. Trend type distribution was strongly dependent on elevation as majority of greening (with or without interruption) occurred at lower elevation areas at higher elevation were dominantly. Ecoregion based stratification of trend types highlighted some exception to this elevational dependence as high altitude ecoregions of western Himalayas showed significantly less browning compared to the ecoregions in eastern Himalaya. Land cover/use based analysis of trend distribution showed that interrupted greening was most dominant in closed needleleafed forest following by rainfed cropland and mosaic croplands while interrupted browning most dominant in closed to open herbaceous vegetation found at higher elevation areas followed by closed needleleafed forest and closed to open broad leafed evergreen forests. Spatial analysis of trend break timing showed that for majority of areas experiencing interrupted greening, break in trend occurred later compared to areas with interrupted browning where break trend was observed much earlier. These results have significant implications for environmental management in the context of climate change and ecosystem dynamics in the Himalayas.

Quantifying spatial patterns in the Yakama Nation Tribal Forest and Okanogan-Wenatchee National Forest to assess forest health

NASA Astrophysics Data System (ADS)

Wilder, T. F.

2013-05-01

Over the past century western United States have experienced drastic anthropogenic land use change from practices such as agriculture, fire exclusion, and timber harvesting. These changes have complex social, cultural, economic, and ecological interactions and consequences. This research studied landscapes patterns of watersheds with similar LANDFIRE potential vegetation in the Southern Washington Cascades physiographic province, within the Yakama Nation Tribal Forest (YTF) and Okanogan-Wenatchee National Forest, Naches Ranger District (NRD). In the selected watersheds, vegetation-mapping units were delineated and populated based on physiognomy of homogeneous areas of vegetative composition and structure using high-resolution aerial photos. Cover types and structural classes were derived from the raw, photo-interpreted vegetation attributes for individual vegetation mapping units and served as individual and composite response variables to quantify and assess spatial patterns and forest health conditions between the two ownerships. Structural classes in both the NRD and YTF were spatially clustered (Z-score 3.1, p-value 0.01; Z-score 2.3, p-value 0.02, respectively), however, ownership and logging type both explained a significant amount of variance in structural class composition. Based on FRAGSTATS landscape metrics, structural classes in the NRD displayed greater clustering and fragmentation with lower interspersion relative to the YTF. The NRD landscape was comprised of 47.4% understory reinitiation structural class type and associated high FRAGASTAT class metrics demonstrated high aggregation with moderate interspersion. Stem exclusion open canopy displayed the greatest dispersal of structural class types throughout the NRD, but adjacencies were correlated to other class types. In the YTF, stem exclusion open canopy comprised 37.7% of the landscape and displayed a high degree of aggregation and interspersion about clusters throughout the YTF. Composite cover type-structural class spatial autocorrelation was clustered in the NRD (Z-score 5.1, p-value 0.01), while the YTF exhibited a random spatial pattern. After accounting for location effects, logging type was the most significant factor explaining variation in composite cover-structure composition. FRAGSTATS landscape metrics identified composite cover-structure classes in the NRD displayed greater aggregation and fragmentation with lower interspersion relative to the YTF. The NRD landscape was comprised of 30.5% Pinus ponderosa-understory reinitiation and associated class metrics demonstrated a high degree of aggregation and fragmentation with low interspersion. Pinus ponderosa-stem exclusion open canopy comprised 24.6% of the YTF landscape and associated class metrics displayed moderate aggregation and fragmentation with high interspersion. A discussion integrating the results and existing relevant literature was indited to assess management regime influences on landscape patterns and, in turn, forest health attributes. This dialog is in provision of enhancing collaboration to optimize forest-health restoration activities across ownerships throughout the study area.

Climate-vegetation modelling and fossil plant data suggest low atmospheric CO2 in the late Miocene

NASA Astrophysics Data System (ADS)

Forrest, M.; Eronen, J. T.; Utescher, T.; Knorr, G.; Stepanek, C.; Lohmann, G.; Hickler, T.

2015-12-01

There is an increasing need to understand the pre-Quaternary warm climates, how climate-vegetation interactions functioned in the past, and how we can use this information to understand the present. Here we report vegetation modelling results for the Late Miocene (11-7 Ma) to study the mechanisms of vegetation dynamics and the role of different forcing factors that influence the spatial patterns of vegetation coverage. One of the key uncertainties is the atmospheric concentration of CO2 during past climates. Estimates for the last 20 million years range from 280 to 500 ppm. We simulated Late Miocene vegetation using two plausible CO2 concentrations, 280 ppm CO2 and 450 ppm CO2, with a dynamic global vegetation model (LPJ-GUESS) driven by climate input from a coupled AOGCM (Atmosphere-Ocean General Circulation Model). The simulated vegetation was compared to existing plant fossil data for the whole Northern Hemisphere. For the comparison we developed a novel approach that uses information of the relative dominance of different plant functional types (PFTs) in the palaeobotanical data to provide a quantitative estimate of the agreement between the simulated and reconstructed vegetation. Based on this quantitative assessment we find that pre-industrial CO2 levels are largely consistent with the presence of seasonal temperate forests in Europe (suggested by fossil data) and open vegetation in North America (suggested by multiple lines of evidence). This suggests that during the Late Miocene the CO2 levels have been relatively low, or that other factors that are not included in the models maintained the seasonal temperate forests and open vegetation.

Characteristics of nitrogen balance in open-air and greenhouse vegetable cropping systems of China.

PubMed

Ti, Chaopu; Luo, Yongxia; Yan, Xiaoyuan

2015-12-01

Nitrogen (N) loss from vegetable cropping systems has become a significant environmental issue in China. In this study, estimation of N balances in both open-air and greenhouse vegetable cropping systems in China was established. Results showed that the total N input in open-air and greenhouse vegetable cropping systems in 2010 was 5.44 and 2.60 Tg, respectively. Chemical fertilizer N input in the two cropping systems was 201 kg N ha(-1) per season (open-air) and 478 kg N ha(-1) per season (greenhouse). The N use efficiency (NUE) was 25.9 ± 13.3 and 19.7 ± 9.4% for open-air and greenhouse vegetable cropping systems, respectively, significantly lower than that of maize, wheat, and rice. Approximately 30.6% of total N input was accumulated in soils and 0.8% was lost by ammonia volatilization in greenhouse vegetable system, while N accumulation and ammonia volatilization accounted for 19.1 and 11.1%, respectively, of total N input in open-air vegetable systems.

Analyses of plant biomarkers in modern ecosystems to improve vegetation reconstructions at hominid sites

NASA Astrophysics Data System (ADS)

Uno, K. T.; Boisserie, J. R.; Cerling, T. E.; Polissar, P. J.

2017-12-01

Reconstructing vegetation at hominid localities in eastern Africa remains a significant challenge for examining the role of climate and environment in human evolution. Plant wax biomarker approaches, particularly carbon isotopes of n-alkyl lipids, have been increasingly used to estimate the proportion of C3 and C4­ vegetation in past environments. Identifying new biomarkers indicative of vegetation type, specifically those that can be used to identify (C3) grasses prior to the late Miocene C4 expansion, will enable vegetation reconstructions during the first half of the Neogene, where much remains to be learned about hominid environments. Here, we begin to look beyond carbon isotopes from n-alkyl lipids by analyzing molecular distributions and screening for new plant biomarkers that can be used to identify plant functional types or possibly, more specific taxonomic information. We evaluate molecular distributions, carbon isotope ratios, and pentacyclic triterpenoid methyl esters (PTMEs) in modern soils from a wide range of ecosystems in Ethiopia and Kenya where vegetation types, fraction woody cover, and climatic conditions are known. Preliminary data suggest PTMEs are associated with grassy ecosystems but absent from forested ones. We also find that woody cover can be estimated using n-alkane molecular distributions. This non-isotopic approach to reconstructing woody cover opens the door to reconstructing Neogene vegetation provided the molecular distributions of C3 grasses in the past are similar to those of modern C4 grasses.

Nellis and Creech Air Force Bases Capital Improvements Program Environmental Assessment

DTIC Science & Technology

2008-09-01

of Nellis AFB are primarily open range and mountains, with urban uses along US-93. Directly southwest of the base, commercial and residential land...construction activities, Nellis AFB is primarily an urban environment with some relatively undisturbed lands lying to the east and north of the base...habitat types are present on the base: urban areas, open space recreation (e.g., golf course), and native desertscrub vegetation. Common bird species

Regional paleofire regimes affected by non-uniform climate, vegetation and human drivers

NASA Astrophysics Data System (ADS)

Blarquez, Olivier; Ali, Adam A.; Girardin, Martin P.; Grondin, Pierre; Fréchette, Bianca; Bergeron, Yves; Hély, Christelle

2015-09-01

Climate, vegetation and humans act on biomass burning at different spatial and temporal scales. In this study, we used a dense network of sedimentary charcoal records from eastern Canada to reconstruct regional biomass burning history over the last 7000 years at the scale of four potential vegetation types: open coniferous forest/tundra, boreal coniferous forest, boreal mixedwood forest and temperate forest. The biomass burning trajectories were compared with regional climate trends reconstructed from general circulation models, tree biomass reconstructed from pollen series, and human population densities. We found that non-uniform climate, vegetation and human drivers acted on regional biomass burning history. In the open coniferous forest/tundra and dense coniferous forest, the regional biomass burning was primarily shaped by gradual establishment of less climate-conducive burning conditions over 5000 years. In the mixed boreal forest an increasing relative proportion of flammable conifers in landscapes since 2000 BP contributed to maintaining biomass burning constant despite climatic conditions less favourable to fires. In the temperate forest, biomass burning was uncoupled with climatic conditions and the main driver was seemingly vegetation until European colonization, i.e. 300 BP. Tree biomass and thus fuel accumulation modulated fire activity, an indication that biomass burning is fuel-dependent and notably upon long-term co-dominance shifts between conifers and broadleaf trees.

Habitat choice by juvenile cod ( Gadus morhua L.) on sandy soft bottoms with different vegetation types

NASA Astrophysics Data System (ADS)

Borg, Å.; Pihl, L.; Wennhage, H.

1997-08-01

Habitat choice by juvenile cod ( Gadus morhua L.) on sandy bottoms with different vegetation types was studied in laboratory. The experiment was conducted day and night in flow-through tanks on two different size-classes of cod (7-13 and 17-28 cm TL). Four habitats, typical of shallow soft bottoms on the Swedish west coast: Fucus vesiculosus, Zostera marina, Cladophora sp. and bare sand, were set up pair-wise in six combinations. The main difference between habitats in this study was vegetation structure, since all parameters except vegetation type was considered equal for both sides of the experimental tanks and natural prey was eliminated. The results showed a difference in habitat utilization by juvenile cod between day (light) and night (dark). During day time the fishes showed a significant preference for vegetation, while nocturnally no significant choice of habitat was made. Both size-classes preferred Fucus, considered the most complex habitat in this study, when this was available. The smaller size-class seemed to be able to utilize the other vegetation types as well, always preferring vegetation over sand. Larger juvenile cod, on the other hand, appeared to be restricted to Fucus. This difference in habitat choice by the two size-classes might be due to a greater dependence on shelter from predation by the smaller juveniles, causing them to associate more strongly with vegetation. The larger juveniles avoided Cladophora, since they might have difficulties in entering the compact structure of this filamentous algae. Availability of vegetation at day time, as a predation refuge, as well as of open sandy areas for feeding during night, thus seems to be important for juvenile cod. It is concluded that eutrophication-induced changes in habitat structure, such as increased dominance by filamentous algae, could alter the availability of predation refuges and foraging habitats for juvenile cod.

Characterization of subarctic vegetation using ground based remote sensing methods

NASA Astrophysics Data System (ADS)

Finnell, D.; Garnello, A.; Palace, M. W.; Sullivan, F.; Herrick, C.; Anderson, S. M.; Crill, P. M.; Varner, R. K.

2014-12-01

Stordalen mire is located at 68°21'N and 19°02'E in the Swedish subarctic. Climate monitoring has revealed a warming trend spanning the past 150 years affecting the mires ability to hold stable palsa/hummock mounds. The micro-topography of the landscape has begun to degrade into thaw ponds changing the vegetation cover from ombrothrophic to minerotrophic. Hummocks are ecologically important due to their ability to act as a carbon sinks. Thaw ponds and sphagnum rich transitional zones have been documented as sources of atmospheric CH4. An objective of this project is to determine if a high resolution three band camera (RGB) and a RGNIR camera could detect differences in vegetation over five different site types. Species composition was collected for 50 plots with ten repetitions for each site type: palsa/hummock, tall shrub, semi-wet, tall graminoid, and wet. Sites were differentiated based on dominating species and features consisting of open water presence, sphagnum spp. cover, graminoid spp. cover, or the presence of dry raised plateaus/mounds. A pole based camera mount was used to collect images at a height of ~2.44m from the ground. The images were cropped in post-processing to fit a one-square meter quadrat. Texture analysis was performed on all images, including entropy, lacunarity, and angular second momentum. Preliminary results suggested that site type influences the number of species present. The p-values for the ability to predict site type using a t-test range from <0.0001 to 0.0461. A stepwise discriminant analysis on site type vs. texture yielded a 10% misclassification rate. Through the use of a stepwise regression of texture variables, actual vs. predicted percent of vegetation coverage provided R squared values of 0.73, 0.71, 0.67, and 0.89 for C. bigelowii, R. chamaemorus, Sphagnum spp., and open water respectively. These data have provided some support to the notion that texture analyses can be used for classification of mire site types. Future work will involve scaling up from the 50 plots through the use of data collected from two unmanned aerial systems (UAS), as well as WorldView-2 satellite imagery collected during the years 2012-2014. Identification of methane flux regions will later be analyzed based on vegetation coverage to aid classification of increased emission zones within the mire.

Fossil evidence for open, Proteaceae-dominated heathlands and fire in the Late Cretaceous of Australia.

PubMed

Carpenter, Raymond J; Macphail, Michael K; Jordan, Gregory J; Hill, Robert S

2015-12-01

The origin of biomes is of great interest globally. Molecular phylogenetic and pollen evidence suggest that several plant lineages that now characterize open, burnt habitats of the sclerophyll biome, became established during the Late Cretaceous of Australia. However, whether this biome itself dates to that time is problematic, fundamentally because of the near-absence of relevant, appropriately aged, terrestrial plant macro- or mesofossils. We recovered, identified, and interpreted the ecological significance of fossil pollen, foliar and other remains from a section of core drilled in central Australia, which we dated as Late Campanian-Maastrichtian. The sediments contain plant fossils that indicate nutrient-limited, open, sclerophyllous vegetation and abundant charcoal as evidence of fire. Most interestingly, >30 pollen taxa and at least 12 foliage taxa are attributable to the important Gondwanan family Proteaceae, including several minute, amphistomatic, and sclerophyllous foliage forms consistent with subfamily Proteoideae. Microfossils, including an abundance of Sphagnales and other wetland taxa, provided strong evidence of a fenland setting. The local vegetation also included diverse Ericaceae and Liliales, as well as a range of ferns and gymnosperms. The fossils provide strong evidence in support of hypotheses of great antiquity for fire and open vegetation in Australia, point to extraordinary persistence of Proteaceae that are now emblematic of the Mediterranean-type climate southwestern Australian biodiversity hotspot and raise the profile of open habitats as centers of ancient lineages. © 2015 Botanical Society of America.

Influences of prior wildfires on vegetation response to subsequent fire in a reburned Southwestern landscape.

PubMed

Coop, Jonathan D; Parks, Sean A; McClernan, Sarah R; Holsinger, Lisa M

2016-03-01

Large and severe wildfires have raised concerns about the future of forested landscapes in the southwestern United States, especially under repeated burning. In 2011, under extreme weather and drought conditions, the Las Conchas fire burned over several previous burns as well as forests not recently exposed to fire. Our purpose was to examine the influences of prior wildfires on plant community composition and structure, subsequent burn severity, and vegetation response. To assess these relationships, we used satellite-derived measures of burn severity and a nonmetric multidimensional scaling of pre- and post- Las Conchas field samples. Earlier burns were associated with shifts from forested sites to open savannas and meadows, oak scrub, and ruderal communities. These non-forested vegetation types exhibited both resistance to subsequent fire, measured by reduced burn severity, and resilience to reburning, measured by vegetation recovery relative to forests not exposed to recent prior fire. Previous shifts toward non-forested states were strongly reinforced by reburning. Ongoing losses of forests and their ecological values confirm the need for restoration interventions. However, given future wildfire and climate projections, there may also be opportunities presented by transformations toward fire-resistant and resilient vegetation types within portions of the landscape.

Where to Combat Shrub Encroachment in Alpine Timberline Ecosystems: Combining Remotely-Sensed Vegetation Information with Species Habitat Modelling

PubMed Central

Braunisch, Veronika; Patthey, Patrick; Arlettaz, Raphaël

2016-01-01

In many cultural landscapes, the abandonment of traditional grazing leads to encroachment of pastures by woody plants, which reduces habitat heterogeneity and impacts biodiversity typical of semi-open habitats. We developed a framework of mutually interacting spatial models to locate areas where shrub encroachment in Alpine treeline ecosystems deteriorates vulnerable species’ habitat, using black grouse Tetrao tetrix (L.) in the Swiss Alps as a study model. Combining field observations and remote-sensing information we 1) identified and located the six predominant treeline vegetation types; 2) modelled current black grouse breeding habitat as a function thereof so as to derive optimal habitat profiles; 3) simulated from these profiles the theoretical spatial extension of breeding habitat when assuming optimal vegetation conditions throughout; and used the discrepancy between (2) and (3) to 4) locate major aggregations of homogeneous shrub vegetation in otherwise suitable breeding habitat as priority sites for habitat restoration. All six vegetation types (alpine pasture, coniferous forest, Alnus viridis (Chaix), Rhododendron-dominated, Juniperus-dominated and mixed heathland) were predicted with high accuracy (AUC >0.9). Breeding black grouse preferred a heterogeneous mosaic of vegetation types, with none exceeding 50% cover. While 15% of the timberline belt currently offered suitable breeding habitat, twice that fraction (29%) would potentially be suitable when assuming optimal shrub and ground vegetation conditions throughout the study area. Yet, only 10% of this difference was attributed to habitat deterioration by shrub-encroachment of dense heathland (all types 5.2%) and Alnus viridis (4.8%). The presented method provides both a general, large-scale assessment of areas covered by dense shrub vegetation as well as specific target values and priority areas for habitat restoration related to a selected target organism. This facilitates optimizing the spatial allocation of management resources in geographic regions where shrub encroachment represents a major biodiversity conservation issue. PMID:27727325

High net CO2 and CH4 release at a eutrophic shallow lake on a formerly drained fen

NASA Astrophysics Data System (ADS)

Franz, Daniela; Koebsch, Franziska; Larmanou, Eric; Augustin, Jürgen; Sachs, Torsten

2016-05-01

Drained peatlands often act as carbon dioxide (CO2) hotspots. Raising the groundwater table is expected to reduce their CO2 contribution to the atmosphere and revitalise their function as carbon (C) sink in the long term. Without strict water management rewetting often results in partial flooding and the formation of spatially heterogeneous, nutrient-rich shallow lakes. Uncertainties remain as to when the intended effect of rewetting is achieved, as this specific ecosystem type has hardly been investigated in terms of greenhouse gas (GHG) exchange. In most cases of rewetting, methane (CH4) emissions increase under anoxic conditions due to a higher water table and in terms of global warming potential (GWP) outperform the shift towards CO2 uptake, at least in the short term.Based on eddy covariance measurements we studied the ecosystem-atmosphere exchange of CH4 and CO2 at a shallow lake situated on a former fen grassland in northeastern Germany. The lake evolved shortly after flooding, 9 years previous to our investigation period. The ecosystem consists of two main surface types: open water (inhabited by submerged and floating vegetation) and emergent vegetation (particularly including the eulittoral zone of the lake, dominated by Typha latifolia). To determine the individual contribution of the two main surface types to the net CO2 and CH4 exchange of the whole lake ecosystem, we combined footprint analysis with CH4 modelling and net ecosystem exchange partitioning.The CH4 and CO2 dynamics were strikingly different between open water and emergent vegetation. Net CH4 emissions from the open water area were around 4-fold higher than from emergent vegetation stands, accounting for 53 and 13 g CH4 m-2 a-1 respectively. In addition, both surface types were net CO2 sources with 158 and 750 g CO2 m-2 a-1 respectively. Unusual meteorological conditions in terms of a warm and dry summer and a mild winter might have facilitated high respiration rates. In sum, even after 9 years of rewetting the lake ecosystem exhibited a considerable C loss and global warming impact, the latter mainly driven by high CH4 emissions. We assume the eutrophic conditions in combination with permanent high inundation as major reasons for the unfavourable GHG balance.

[Spatio-temporal dynamic of green lacewings (Neuroptera: Chrysopidae) taxocenosis on natural ecosystems].

PubMed

Costa, Renildo I F; Souza, Brígida; Freitas, Sérgio De

2010-01-01

In order to study the interactions of green lacewings toxocenosis on natural ecossystems, samplings were carried out in the Parque Ecológico Quedas do Rio Bonito, located in Lavras, Alto Rio Grande region, South of Minas Gerais, Brazil. The species inventory was accomplished in two vegetation types: semi-evergreen forest and open field formations, including areas of montane grassland, rocky montane grassland and "cerrado". Insects were captured with a butterfly net during 2h, walking through each vegetation formation. Sampling resulted in 1,948 specimens belonging to 30 species, of which 14 were Chrysopini and 16 Leucochrysini. Representatives of these tribes were observed both in forest and in open field formations. Species of the genera Ceraeochrysa, Chrysoperla, Chrysopodes, Plesiochrysa and Leucochrysa were found in forests and in open field formations, except for Plesiochrysa. The highest richness and diversity of species were observed in the forest. The similarity index among the communities of green lacewings in the studied areas was 27%.

Micro-zooplankton grazing as a means of fecal bacteria removal in stormwater BMPs.

PubMed

Burtchett, Jade M; Mallin, Michael A; Cahoon, Lawrence B

2017-06-01

A priority for environmental managers is control of stormwater runoff pollution, especially fecal microbial pollution. This research was designed to determine if fecal bacterial grazing by micro-zooplankton is a significant control on fecal bacteria in aquatic best management practices (BMPs); if grazing differs between a wet detention pond and a constructed wetland; and if environmental factors enhance grazing. Both 3-day grazing tests and 24-h dilution assays were used to determine grazing differences between the two types of BMP. Micro-zooplankton grazing was a stronger bacteria removal mechanism in stormwater wetlands rich in aquatic vegetation compared to a standard wet detention pond, although grazing was important in detention ponds as well. Our experiments indicated that the majority of grazers that fed on fecal bacteria were <20 μm in size. Grazing rates were positively correlated with fecal coliform abundance and increased water temperatures. Enumeration of grazers demonstrated that protozoans were significantly more abundant among wetland vegetation than in open water, and open wetland waters contained more flagellates and dinoflagellates than open wet detention pond waters. Grazing on fecal bacteria in BMPs is enhanced by aquatic vegetation, and grazing in aquatic BMPs in warmer climates should be greater than in cooler climates.

Regional paleofire regimes affected by non-uniform climate, vegetation and human drivers

PubMed Central

Blarquez, Olivier; Ali, Adam A.; Girardin, Martin P.; Grondin, Pierre; Fréchette, Bianca; Bergeron, Yves; Hély, Christelle

2015-01-01

Climate, vegetation and humans act on biomass burning at different spatial and temporal scales. In this study, we used a dense network of sedimentary charcoal records from eastern Canada to reconstruct regional biomass burning history over the last 7000 years at the scale of four potential vegetation types: open coniferous forest/tundra, boreal coniferous forest, boreal mixedwood forest and temperate forest. The biomass burning trajectories were compared with regional climate trends reconstructed from general circulation models, tree biomass reconstructed from pollen series, and human population densities. We found that non-uniform climate, vegetation and human drivers acted on regional biomass burning history. In the open coniferous forest/tundra and dense coniferous forest, the regional biomass burning was primarily shaped by gradual establishment of less climate-conducive burning conditions over 5000 years. In the mixed boreal forest an increasing relative proportion of flammable conifers in landscapes since 2000 BP contributed to maintaining biomass burning constant despite climatic conditions less favourable to fires. In the temperate forest, biomass burning was uncoupled with climatic conditions and the main driver was seemingly vegetation until European colonization, i.e. 300 BP. Tree biomass and thus fuel accumulation modulated fire activity, an indication that biomass burning is fuel-dependent and notably upon long-term co-dominance shifts between conifers and broadleaf trees. PMID:26330162

Air Pollution Abatement Performances of Green Infrastructure in Open Road and Built-up Street Canyon Environments – A Review

EPA Science Inventory

Intensifying the proportion of urban green infrastructure has been considered as one of the remedies for air pollution levels in cities, yet the impact of numerous vegetation types deployed in different built environments has to be fully synthesised and quantified. This review ex...

Comparing vegetation types and anthropic disturbance levels in the Atlantic forest: how do Pentatomoidea (Hemiptera: Heteroptera) assemblages respond?

PubMed

Bianchi, F M; Mendonça, M S; Campos, L A

2014-12-01

The Atlantic Forest (AF) is considered the most fragmented and endangered Brazilian biome. The diversity of phytophagous insects increases after disturbances in forests, and it was hypothesized the Pentatomidae can furnish ecologically reliable information in terms of diversity in response to the changes occurring in AF. Our aim was to quantify the response of assemblages of Pentatomoidea to gradient of human disturbance in two vegetation types of the AF-dense ombrophilous forest (DOF) and mixed ombrophilous forest (MOF). Twelve transects were grouped into environmental classes, namely open, intermediate, and closed. Overall, 1,017 pentatomoids were sampled, representing 64 species. The open environment was more abundant than closed environment, though it is expected that Pentatomoidea respond with increasing abundance when under light or moderate disturbance. The MOF was more abundant than DOF, and the composition differed between both of them. Given the differences in composition between MOF and DOF, abiotic variables are important factors acting as environmental filters for Pentatomoidea, not just directly on the insects, but probably also on the nutritional support of their host plants.

Active season microhabitat and vegetation selection by giant gartersnakes associated with a restored marsh in California

USGS Publications Warehouse

Halstead, Brian J.; Valcarcel, Patricia; Wylie, Glenn D.; Coates, Peter S.; Casazza, Michael L.; Rosenberg, Daniel K.

2016-01-01

Studies of habitat selection can reveal important patterns to guide habitat restoration and management for species of conservation concern. Giant gartersnakes Thamnophis gigas are endemic to the Central Valley of California, where >90% of their historical wetland habitat has been converted to agricultural and other uses. Information about the selection of habitats by individual giant gartersnakes would guide habitat restoration by indicating which habitat features and vegetation types are likely to be selected by these rare snakes. We examined activity patterns and selection of microhabitats and vegetation types by adult female giant gartersnakes with radiotelemetry at a site composed of rice agriculture and restored wetlands using a paired case-control study design. Adult female giant gartersnakes were 14.7 (95% credible interval [CRI] = 9.4–23.7) times more likely to be active (foraging, mating, or moving) when located in aquatic habitats than when located in terrestrial habitats. Microhabitats associated with cover—particularly emergent vegetation, terrestrial vegetation, and litter—were positively selected by giant gartersnakes. Individual giant gartersnakes varied greatly in their selection of rice and rock habitats, but varied little in their selection of open water. Tules Schoenoplectus acutus were the most strongly selected vegetation type, and duckweed Lemna spp., water-primrose Ludwigia spp., forbs, and grasses also were positively selected at the levels of availability observed at our study site. Management practices that promote the interface of water with emergent aquatic and herbaceous terrestrial vegetation will likely benefit giant gartersnakes. Given their strong selection of tules, restoration of native tule marshes will likely provide the greatest benefit to these threatened aquatic snakes.

Evaluating the use of in-store measures in retail food stores and restaurants in Brazil.

PubMed

Duran, Ana Clara; Lock, Karen; Latorre, Maria do Rosario D O; Jaime, Patricia Constante

2015-01-01

To assess inter-rater reliability, test-retest reliability, and construct validity of retail food store, open-air food market, and restaurant observation tools adapted to the Brazilian urban context. This study is part of a cross-sectional observation survey conducted in 13 districts across the city of Sao Paulo, Brazil in 2010-2011. Food store and restaurant observational tools were developed based on previously available tools, and then tested it. They included measures on the availability, variety, quality, pricing, and promotion of fruits and vegetables and ultra-processed foods. We used Kappa statistics and intra-class correlation coefficients to assess inter-rater and test-retest reliabilities in samples of 142 restaurants, 97 retail food stores (including open-air food markets), and of 62 restaurants and 45 retail food stores (including open-air food markets), respectively. Construct validity as the tool's abilities to discriminate based on store types and different income contexts were assessed in the entire sample: 305 retail food stores, 8 fruits and vegetable markets, and 472 restaurants. Inter-rater and test-retest reliability were generally high, with most Kappa values greater than 0.70 (range 0.49-1.00). Both tools discriminated between store types and neighborhoods with different median income. Fruits and vegetables were more likely to be found in middle to higher-income neighborhoods, while soda, fruit-flavored drink mixes, cookies, and chips were cheaper and more likely to be found in lower-income neighborhoods. The measures were reliable and able to reveal significant differences across store types and different contexts. Although some items may require revision, results suggest that the tools may be used to reliably measure the food stores and restaurant food environment in urban settings of middle-income countries. Such studies can help .inform health promotion interventions and policies in these contexts.

Evaluating the use of in-store measures in retail food stores and restaurants in Brazil

PubMed Central

Duran, Ana Clara; Lock, Karen; Latorre, Maria do Rosario D O; Jaime, Patricia Constante

2015-01-01

ABSTRACT OBJECTIVE To assess inter-rater reliability, test-retest reliability, and construct validity of retail food store, open-air food market, and restaurant observation tools adapted to the Brazilian urban context. METHODS This study is part of a cross-sectional observation survey conducted in 13 districts across the city of Sao Paulo, Brazil in 2010-2011. Food store and restaurant observational tools were developed based on previously available tools, and then tested it. They included measures on the availability, variety, quality, pricing, and promotion of fruits and vegetables and ultra-processed foods. We used Kappa statistics and intra-class correlation coefficients to assess inter-rater and test-retest reliabilities in samples of 142 restaurants, 97 retail food stores (including open-air food markets), and of 62 restaurants and 45 retail food stores (including open-air food markets), respectively. Construct validity as the tool’s abilities to discriminate based on store types and different income contexts were assessed in the entire sample: 305 retail food stores, 8 fruits and vegetable markets, and 472 restaurants. RESULTS Inter-rater and test-retest reliability were generally high, with most Kappa values greater than 0.70 (range 0.49-1.00). Both tools discriminated between store types and neighborhoods with different median income. Fruits and vegetables were more likely to be found in middle to higher-income neighborhoods, while soda, fruit-flavored drink mixes, cookies, and chips were cheaper and more likely to be found in lower-income neighborhoods. CONCLUSIONS The measures were reliable and able to reveal significant differences across store types and different contexts. Although some items may require revision, results suggest that the tools may be used to reliably measure the food stores and restaurant food environment in urban settings of middle-income countries. Such studies can help .inform health promotion interventions and policies in these contexts. PMID:26538101

Effectiveness of a Parent Health Report in Increasing Fruit and Vegetable Consumption Among Preschoolers and Kindergarteners.

PubMed

Hunsaker, Sanita L; Jensen, Chad D

2017-05-01

To determine the effectiveness of a parent health report on fruit and vegetable consumption among preschoolers and kindergarteners. Pre-post open design trial and a randomized controlled trial. A university-sponsored preschool and kindergarten. A total of 63 parents of preschool and kindergarten students participated in the pre-post open design trial and 65 parents participated in the randomized controlled trial. Parents in intervention groups were given a parent health report providing information about their child's fruit and vegetable intake as well as recommendations for how to increase their child's fruit and vegetable consumption. Change in fruit and vegetable consumption. Latent growth curve modeling with Bayesian estimation. Vegetable consumption increased by 0.3 servings/d in the open trial and 0.65 servings/d in the randomized trial. Fruit consumption did not increase significantly in either study. Results from both an open trial and a randomized controlled trial suggested that the parent health report may be a beneficial tool to increase vegetable consumption in preschoolers and kindergarteners. Increases in vegetable consumption can lead to the establishment of lifelong habits of healthy vegetable intake and decrease risk for chronic diseases. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

Sub-canopy evapotranspiration from floating vegetation and open water in a swamp forest

USDA-ARS?s Scientific Manuscript database

Among previous studies, there are large discrepancies in the difference between evapotranspiration from wetland vegetation and evaporation from open water. In this study, we investigate evapotranspiration differences between water and vegetation in a scenario that has otherwise not been extensively ...

Summer carbon dioxide and water vapor fluxes across a range of northern peatlands

NASA Astrophysics Data System (ADS)

Humphreys, Elyn R.; Lafleur, Peter M.; Flanagan, Lawrence B.; Hedstrom, Newell; Syed, Kamran H.; Glenn, Aaron J.; Granger, Raoul

2006-12-01

Northern peatlands are a diverse group of ecosystems varying along a continuum of hydrological, chemical, and vegetation gradients. These ecosystems contain about one third of the global soil carbon pool, but it is uncertain how carbon and water cycling processes and response to climate change differ among peatland types. This study examines midsummer CO2 and H2O fluxes measured using the eddy covariance technique above seven northern peatlands including a low-shrub bog, two open poor fens, two wooded moderately rich fens, and two open extreme-rich fens. Gross ecosystem production and ecosystem respiration correlated positively with vegetation indices and with each other. Consequently, 24-hour net ecosystem CO2 exchange was similar among most of the sites (an average net carbon sink of 1.5 ± 0.2 g C m-2 d-1) despite large differences in water table depth, water chemistry, and plant communities. Evapotranspiration was primarily radiatively driven at all sites but a decline in surface conductance with increasing water vapor deficit indicated physiological restrictions to transpiration, particularly at the peatlands with woody vegetation and less at the peatlands with 100% Sphagnum cover. Despite these differences, midday evapotranspiration ranged only from 0.21 to 0.34 mm h-1 owing to compensation among the factors controlling evapotranspiration. Water use efficiency varied among sites primarily as a result of differences in productivity and plant functional type. Although peatland classification includes a great variety of ecosystem characteristics, peatland type may not be an effective way to predict the magnitude and characteristics of midsummer CO2 and water vapor exchanges.

Dynamics of active layer in wooded palsas of northern Quebec

NASA Astrophysics Data System (ADS)

Jean, Mélanie; Payette, Serge

2014-02-01

Palsas are organic or mineral soil mounds having a permafrost core. Palsas are widespread in the circumpolar discontinuous permafrost zone. The annual dynamics and evolution of the active layer, which is the uppermost layer over the permafrost table and subjected to the annual freeze-thaw cycle, are influenced by organic layer thickness, snow depth, vegetation type, topography and exposure. This study examines the influence of vegetation types, with an emphasis on forest cover, on active layer dynamics of palsas in the Boniface River watershed (57°45‧ N, 76°00‧ W). In this area, palsas are often colonized by black spruce trees (Picea mariana (Mill.) B.S.P.). Thaw depth and active layer thickness were monitored on 11 wooded or non-wooded mineral and organic palsas in 2009, 2010 and 2011. Snow depth, organic layer thickness, and vegetation types were assessed. The mapping of a palsa covered by various vegetation types and a large range of organic layer thickness were used to identify the factors influencing the spatial patterns of thaw depth and active layer. The active layer was thinner and the thaw rate slower in wooded palsas, whereas it was the opposite in more exposed sites such as forest openings, shrubs and bare ground. Thicker organic layers were associated with thinner active layers and slower thaw rates. Snow depth was not an important factor influencing active layer dynamics. The topography of the mapped palsa was uneven, and the environmental factors such as organic layer, snow depth, and vegetation types were heterogeneously distributed. These factors explain a part of the spatial variation of the active layer. Over the 3-year long study, the area of one studied palsa decreased by 70%. In a context of widespread permafrost decay, increasing our understanding of factors that influence the dynamics of wooded and non-wooded palsas and understanding of the role of vegetation cover will help to define the response of discontinuous permafrost landforms to changing climatic conditions.

Climate change and northern prairie wetlands: Simulations of long-term dynamics

USGS Publications Warehouse

Poiani, Karen A.; Johnson, W. Carter; Swanson, George A.; Winter, Thomas C.

1996-01-01

A mathematical model (WETSIM 2.0) was used to simulate wetland hydrology and vegetation dynamics over a 32-yr period (1961–1992) in a North Dakota prairie wetland. A hydrology component of the model calculated changes in water storage based on precipitation, evapotranspiration, snowpack, surface runoff, and subsurface inflow. A spatially explicit vegetation component in the model calculated changes in distribution of vegetative cover and open water, depending on water depth, seasonality, and existing type of vegetation.The model reproduced four known dry periods and one extremely wet period during the three decades. One simulated dry period in the early 1980s did not actually occur. Simulated water levels compared favorably with continuous observed water levels outside the calibration period (1990–1992). Changes in vegetative cover were realistic except for years when simulated water levels were significantly different than actual levels. These generally positive results support the use of the model for exploring the effects of possible climate changes on wetland resources.

Understanding interaction effects of climate change and fire management on bird distributions through combined process and habitat models

USGS Publications Warehouse

White, Joseph D.; Gutzwiller, Kevin J.; Barrow, Wylie C.; Johnson-Randall, Lori; Zygo, Lisa; Swint, Pamela

2011-01-01

Avian conservation efforts must account for changes in vegetation composition and structure associated with climate change. We modeled vegetation change and the probability of occurrence of birds to project changes in winter bird distributions associated with climate change and fire management in the northern Chihuahuan Desert (southwestern U.S.A.). We simulated vegetation change in a process-based model (Landscape and Fire Simulator) in which anticipated climate change was associated with doubling of current atmospheric carbon dioxide over the next 50 years. We estimated the relative probability of bird occurrence on the basis of statistical models derived from field observations of birds and data on vegetation type, topography, and roads. We selected 3 focal species, Scaled Quail (Callipepla squamata), Loggerhead Shrike (Lanius ludovicianus), and Rock Wren (Salpinctes obsoletus), that had a range of probabilities of occurrence for our study area. Our simulations projected increases in relative probability of bird occurrence in shrubland and decreases in grassland and Yucca spp. and ocotillo (Fouquieria splendens) vegetation. Generally, the relative probability of occurrence of all 3 species was highest in shrubland because leaf-area index values were lower in shrubland. This high probability of occurrence likely is related to the species' use of open vegetation for foraging. Fire suppression had little effect on projected vegetation composition because as climate changed there was less fuel and burned area. Our results show that if future water limits on plant type are considered, models that incorporate spatial data may suggest how and where different species of birds may respond to vegetation changes.

Understanding interaction effects of climate change and fire management on bird distributions through combined process and habitat models

USGS Publications Warehouse

White, Joseph D.; Gutzwiller, Kevin J.; Barrow, Wylie C.; Johnson-Randall, Lori; Zygo, Lisa; Swint, Pamela

2011-01-01

Avian conservation efforts must account for changes in vegetation composition and structure associated with climate change. We modeled vegetation change and the probability of occurrence of birds to project changes in winter bird distributions associated with climate change and fire management in the northern Chihuahuan Desert (southwestern U.S.A.). We simulated vegetation change in a process-based model (Landscape and Fire Simulator) in which anticipated climate change was associated with doubling of current atmospheric carbon dioxide over the next 50 years. We estimated the relative probability of bird occurrence on the basis of statistical models derived from field observations of birds and data on vegetation type, topography, and roads. We selected 3 focal species, Scaled Quail (Callipepla squamata), Loggerhead Shrike (Lanius ludovicianus), and Rock Wren (Salpinctes obsoletus), that had a range of probabilities of occurrence for our study area. Our simulations projected increases in relative probability of bird occurrence in shrubland and decreases in grassland and Yucca spp. and ocotillo (Fouquieria splendens) vegetation. Generally, the relative probability of occurrence of all 3 species was highest in shrubland because leaf-area index values were lower in shrubland. This high probability of occurrence likely is related to the species' use of open vegetation for foraging. Fire suppression had little effect on projected vegetation composition because as climate changed there was less fuel and burned area. Our results show that if future water limits on plant type are considered, models that incorporate spatial data may suggest how and where different species of birds may respond to vegetation changes. ??2011 Society for Conservation Biology.

Coyote abundance in relation to habitat characteristics in Sierra San Luis, Sonora, Mexico

Treesearch

Eduardo Ponce Guevara; Karla Pelz Serrano; Carlos A. Lopez Gonzalez

2005-01-01

Coyotes have expanded their historical distribution range because of anthropogenic activities and habitat transformation, where forests have been considered marginal habitat. We tested the relationship between vegetation structure and coyote abundance in different habitat types. We expected to find a higher abundance in open lands than in thicker areas. We used scent...

Conservation in metropolitan regions: assessing trends and threats of urban development and climate change

NASA Astrophysics Data System (ADS)

Thorne, J. H.; Santos, M. J.; Bjorkman, J.

2011-12-01

Two global challenges to successful conservation are urban expansion and climate change. Rapid urban growth threatens biodiversity and associated ecosystem services, while climate change may make currently protected areas unsuitable for species that exist within them. We examined three measures of landscape change for 8800 km2 of the San Francisco Bay metropolitan region over 80 years past and future: urban growth, protected area establishment, and natural vegetation type extents. The Bay Area is a good test bed for conservation assessment of the impacts of temporal and spatial of urban growth and land cover change. The region is geographically rather small, with over 40% of its lands already dedicated to protected park and open space lands, they are well-documented, and, the area has had extensive population growth in the past and is projected to continue to grow. The ten-county region within which our study area is a subset has grown from 1.78 million people in 1930, to 6.97 million in 2000 and is estimated to grow to 10.94 million by 2050. With such an influx of people into a small geographic area, it is imperative to both examine the past urban expansion and estimate how the future population will be accommodated into the landscape. We quantify these trends to assess conservation 'success' through time. We used historical and current landcover maps to assess trend, and a GIS-based urban modeling (UPlan) to assess future urban growth impacts in the region, under three policy scenarios- business as usual, smart growth, and urban redevelopment. Impacts are measured by the amount of open space targeted by conservation planners in the region that will be urbanized under each urban growth policy. Impacts are also measured by estimates of the energy consumption projected for each of the scenarios on household and business unit level. The 'business as usual' and 'smart growth' scenarios differed little in their impacts to targeted conservation lands, because so little open space remains to accommodate the expected population growth. Redevelopment conserved more naturally vegetated open space. The redevelopment scenario also permits the lowest increase in energy demand because buildings taken out in the process are reconfigured to higher levels of energy efficiency. However, redevelopment requires substantial increases in residential densities to confine the spatial footprint of the expected future urban growth. These three urban growth scenario footprints differ in their impact to natural vegetation and open space. To incorporate the influence of climate change on remaining natural ecosystems in this urbanizing landscape, we projected the stability of existing, mapped, vegetation types in the region under future climates by examining where projected ranges of the dominant plant species comprising each California Wildlife Habitat Relationship type will all remain together, and where they will begin to dis-associate due to biogeographic response to changing climate. This permits identification of stable and unstable zones of vegetation. The combination of climate stable, high conservation priority and likelihood of urban development provides a way to prioritize conservation land acquisitions.

Temporal dynamics of spectral bioindicators evidence biological and ecological differences among functional types in a cork oak open woodland

NASA Astrophysics Data System (ADS)

Cerasoli, Sofia; Costa e Silva, Filipe; Silva, João M. N.

2016-06-01

The application of spectral vegetation indices for the purpose of vegetation monitoring and modeling increased largely in recent years. Nonetheless, the interpretation of biophysical properties of vegetation through their spectral signature is still a challenging task. This is particularly true in Mediterranean oak forest characterized by a high spatial and temporal heterogeneity. In this study, the temporal dynamics of vegetation indices expected to be related with green biomass and photosynthetic efficiency were compared for the canopy of trees, the herbaceous layer, and two shrub species: cistus ( Cistus salviifolius) and ulex ( Ulex airensis). coexisting in a cork oak woodland. All indices were calculated from in situ measurements with a FieldSpec3 spectroradiometer (ASD Inc., Boulder, USA). Large differences emerged in the temporal trends and in the correlation between climate and vegetation indices. The relationship between spectral indices and temperature, radiation, and vapor pressure deficit for cork oak was opposite to that observed for the herbaceous layer and cistus. No correlation was observed between rainfall and vegetation indices in cork oak and ulex, but in the herbaceous layer and in the cistus, significant correlations were found. The analysis of spectral vegetation indices with fraction of absorbed PAR (fPAR) and quantum yield of chlorophyll fluorescence ( ΔF/ Fm') evidenced strongest relationships with the indices Normalized Difference Water Index (NDWI) and Photochemical Reflectance Index (PRI)512, respectively. Our results, while confirms the ability of spectral vegetation indices to represent temporal dynamics of biophysical properties of vegetation, evidence the importance to consider ecosystem composition for a correct ecological interpretation of results when the spatial resolution of observations includes different plant functional types.

Temporal dynamics of spectral bioindicators evidence biological and ecological differences among functional types in a cork oak open woodland.

PubMed

Cerasoli, Sofia; Costa E Silva, Filipe; Silva, João M N

2016-06-01

The application of spectral vegetation indices for the purpose of vegetation monitoring and modeling increased largely in recent years. Nonetheless, the interpretation of biophysical properties of vegetation through their spectral signature is still a challenging task. This is particularly true in Mediterranean oak forest characterized by a high spatial and temporal heterogeneity. In this study, the temporal dynamics of vegetation indices expected to be related with green biomass and photosynthetic efficiency were compared for the canopy of trees, the herbaceous layer, and two shrub species: cistus (Cistus salviifolius) and ulex (Ulex airensis). coexisting in a cork oak woodland. All indices were calculated from in situ measurements with a FieldSpec3 spectroradiometer (ASD Inc., Boulder, USA). Large differences emerged in the temporal trends and in the correlation between climate and vegetation indices. The relationship between spectral indices and temperature, radiation, and vapor pressure deficit for cork oak was opposite to that observed for the herbaceous layer and cistus. No correlation was observed between rainfall and vegetation indices in cork oak and ulex, but in the herbaceous layer and in the cistus, significant correlations were found. The analysis of spectral vegetation indices with fraction of absorbed PAR (fPAR) and quantum yield of chlorophyll fluorescence (ΔF/Fm') evidenced strongest relationships with the indices Normalized Difference Water Index (NDWI) and Photochemical Reflectance Index (PRI)512, respectively. Our results, while confirms the ability of spectral vegetation indices to represent temporal dynamics of biophysical properties of vegetation, evidence the importance to consider ecosystem composition for a correct ecological interpretation of results when the spatial resolution of observations includes different plant functional types.

Changes in habitat use and distribution of mouflon in the Kahuku Unit of Hawai‘i Volcanoes National Park

USGS Publications Warehouse

Palupe, Bronson; Leopold, Christina R.; Hess, Steven C.; Faford, Jonathan K.; Pacheco, Dexter; Judge, Seth W.

2016-01-01

European mouflon sheep (Ovis gmelini musimon) were introduced to Kahuku Ranch on Hawai‘i Island in 1968 and 1974 for trophy hunting and have been detrimental to the native ecosystem by trampling, bark stripping, and browsing vegetation. In 2003, Hawai‘i Volcanoes National Park acquired Kahuku Ranch and managers began removing mouflon. The objective of this project was to determine whether hunting has changed the distribution of mouflon in Kahuku, to better understand mouflon behaviour and to expedite eradication efforts. Locations from hunting and GPS telemetry data during 2007–14 were used to determine the effect of hunting on mouflon distribution by examining distance to roads and habitat use. Mouflon seemed to avoid roads after hunting pressure increased and their distribution within vegetation types changed over time. Mouflon without hunting pressure were detected in native shrub habitat in 68% of all observations. Hunted mouflon were encountered less in native shrub habitat and more in other habitats including open forest, closed forest, and areas with no vegetation. These changes suggest that hunting has influenced the distribution of mouflon over time away from native shrub and into other vegetation types where they may be more difficult to control.

Vegetation in group selection openings: ecology and manipulation

Treesearch

Philip M. McDonald; Gary O. Fiddler

1991-01-01

Group selection openings ranging from 0.1 to 2.0 acres in mixed conifer stands in northern and central California were evaluated for effect of site preparation, opening size, kind and amount of vegetation, and release treatment. Small openings, in general, are characterized by less sunlight and lower temperature extremes than clearcuttings. Roots from border trees...

Improvement of effectiveness of existing Casuarina equisetifolia forests in mitigating tsunami damage.

PubMed

Samarakoon, M B; Tanaka, Norio; Iimura, Kosuke

2013-01-15

Coastal vegetation can play a significant role in reducing the severity of a tsunami because the energy associated with the tsunami is dissipated when it passes through coastal vegetation. Field surveys were conducted on the eastern coastline of Sri Lanka to investigate which vegetation species are effective against a tsunami and to evaluate the effectiveness of existing Casuarina equisetifolia forests in tsunami mitigation. Open gaps in C. equisetifolia forests were identified as a disadvantage, and introduction of a new vegetation belt in front or back of the existing C. equisetifolia forest is proposed to reduce the disadvantages of the open gap. Among the many plant species encountered during the field survey, ten species were selected as effective for tsunami disaster mitigation. The selection of appropriate vegetation for the front or back vegetation layer was based on the vegetation thickness per unit area (dN(u)) and breaking moment of each species. A numerical model based on two-dimensional nonlinear long-wave equations was applied to explain the present situation of open gaps in C. equisetifolia forests, and to evaluate the effectiveness of combined vegetation systems. The results of the numerical simulation for existing conditions of C. equisetifolia forests revealed that the tsunami force ratio (R = tsunami force with vegetation/tsunami force without vegetation) was 1.4 at the gap exit. The species selected for the front and back vegetation layers were Pandanus odoratissimus and Manilkara hexandra, respectively. A numerical simulation of the modified system revealed that R was reduced to 0.7 in the combined P. odoratissimus and C. equisetifolia system. However, the combination of C. equisetifolia and M. hexandra did not effectively reduce R at the gap exit. Therefore, P. odoratissimus as the front vegetation layer is proposed to reduce the disadvantages of the open gaps in existing C. equisetifolia forests. The optimal width of P. odoratissimus (W(1)) calculated from the numerical simulation was W(1) = 10 m. R at the exit of a 15-m-wide open gap was 0.8, and therefore the proposed system was appropriate for cases with the highest velocity at the gap exit as well. Establishment of a new front vegetation layer except for open gaps that are essential, such as access roads to the beach, is proposed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Student feedback to improve the United States Department of Agriculture Fresh Fruit and Vegetable Program.

PubMed

Lin, Yi-Chun; Fly, Alyce D

2016-06-01

Fruit and vegetable consumption of children in the United States falls below recommendations. The U.S. Department of Agriculture Fresh Fruit and Vegetable Program (FFVP) is a national free-fruit and vegetable school distribution program designed to address this problem. This permanent, legislated program provides funding to qualified elementary schools for provision of additional fruit and vegetables outside of school meals. The objective of this study was to understand children's perceptions of FFVP after the intervention and formulate recommendations that may improve success of the intervention. Secondary data were obtained from 5,265 4(th)-6(th) graders at 51 randomly-selected FFVP intervention schools in Indiana. Anonymous questionnaires were completed late in the 2011-2012 academic year. Multilevel logistic regressions were used to determine associations between students' perceptions of program effects (4 close-ended items) and their preference toward the program. Content analysis was applied to a single open-ended item for program comments. Over 47% of students reported greater intake of fruit and vegetables due to FFVP, and over 66% reported liking the program. Student-reported program effects were positively associated with preference for the program (P < 0.01). Themes that emerged during analysis of 3,811 comments, included, students liked: the opportunity to try different kinds of fruit and vegetables, types and flavors of fruits served, and benefits of eating fruit. Fewer students liked the types of vegetables and their benefits. A small group disliked the program citing poor flavor of vegetables and quality of fruits. Important suggestions for the program include serving more dipping sauces for vegetables, cooking vegetables, and providing a greater variety of produce. The degree that students liked FFVP may predict the program's effects on fruit and vegetable intake. FFVP may become more acceptable to students by incorporating their suggestions. Program planners should consider these options for achieving program goals.

Vegetation Response to Upper Pliocene Glacial/Interglacial Cyclicity in the Central Mediterranean

NASA Astrophysics Data System (ADS)

Combourieu-Nebout, Nathalie

1993-09-01

New detailed pollen analysis of the lower part of the Upper Pliocene Semaforo section (Crotone, Italy) documents cyclic behavior of vegetation at the beginning of the Northern Hemisphere glaciations. The competition between four vegetation units (subtropical humid forest, deciduous temperate forest, altitudinal coniferous forest, and open xeric assemblage) probably reflects modifications of vegetation belts at this montane site. Several increases in herbaceous open vegetation regularly alternate with subtropical humid forest, which expresses rapid climatic oscillations. The complete temporal succession—deciduous forest (rich in Quercus), followed by subtropical humid forest (Taxodiaceae and Cathaya), then altitudinal coniferous forest ( Tsuga, Cedrus, Abies, and Picea), and finally herbaceous open vegetation (Graminae, Compositae, and Artemisia )—displays the climatic evolution from warm and humid interglaciation to cold and dry glaciation. It also suggests an independent variation of temperature and humidity, the two main climatic parameters. The vegetation history of southern Calabria recorded in the Semaforo section have been correlated with the ∂ 18O signal established in the Atlantic Ocean.

[An analysis of nutritional and harmful components of vegetables grown in plastic greenhouses].

PubMed

Yao, H; Yan, W; Li, G; Chen, Y; Guo, W; Wang, G; Xu, Z; Feng, C; Liu, K; Jin, D

1999-09-01

To study the changes in nutritional and harmful components of vegetables grown in plastic greenhouses. In plastic greenhouses, microclimate and air concentrations of carbon monoxide, carbon dioxide, fluoride and respirable particulate were measured, and chlorophyll, total sugar, crude fiber, nitrite, fluoride, arsenic and some mineral elements in vegetables were determined as compared with those grown in the open-air fields. Greenhouse appeared a lower wind speed and darker illumination. Contents of chlorophyll a an b, total chlorophyll, reduced vitamin C, crude fiber in vegetables grown in greenhouse all were lower than those grown in open-air fields. Contents of potassium, calcium, magnesium, iron, zinc, copper and phosphorous were all lower in the vegetables grown in greenhouse than those grown in open-air fields. The contents of chlorophyll reducing Vitamin C. Lower wind speed and inadequate illumination in greenhouse affected photosynthesis and uptake of water in vegetables causing changes in their nutritional components. But, no contamination of burning coal was found in vegetables grown in greenhouse.

Using Support Vector Machines to Automatically Extract Open Water Signatures from POLDER Multi-Angle Data Over Boreal Regions

NASA Technical Reports Server (NTRS)

Pierce, J.; Diaz-Barrios, M.; Pinzon, J.; Ustin, S. L.; Shih, P.; Tournois, S.; Zarco-Tejada, P. J.; Vanderbilt, V. C.; Perry, G. L.; Brass, James A. (Technical Monitor)

2002-01-01

This study used Support Vector Machines to classify multiangle POLDER data. Boreal wetland ecosystems cover an estimated 90 x 10(exp 6) ha, about 36% of global wetlands, and are a major source of trace gases emissions to the atmosphere. Four to 20 percent of the global emission of methane to the atmosphere comes from wetlands north of 4 degrees N latitude. Large uncertainties in emissions exist because of large spatial and temporal variation in the production and consumption of methane. Accurate knowledge of the areal extent of open water and inundated vegetation is critical to estimating magnitudes of trace gas emissions. Improvements in land cover mapping have been sought using physical-modeling approaches, neural networks, and active microwave, examples that demonstrate the difficulties of separating open water, inundated vegetation and dry upland vegetation. Here we examine the feasibility of using a support vector machine to classify POLDER data representing open water, inundated vegetation and dry upland vegetation.

Monitoring vegetation response to episodic disturbance events by using multitemporal vegetation indices

USGS Publications Warehouse

Steyer, Gregory D.; Couvillion, Brady R.; Barras, John A.

2013-01-01

Normalized Difference Vegetation Index (NDVI) derived from MODerate-resolution Imaging Spectroradiometer (MODIS) satellite imagery and land/water assessments from Landsat Thematic Mapper (TM) imagery were used to quantify the extent and severity of damage and subsequent recovery after Hurricanes Katrina and Rita of 2005 within the vegetation communities of Louisiana's coastal wetlands. Field data on species composition and total live cover were collected from 232 unique plots during multiple time periods to corroborate changes in NDVI values over time. Aprehurricane 5-year baseline time series clearly identified NDVI values by habitat type, suggesting the sensitivity of NDVI to assess and monitor phenological changes in coastal wetland habitats. Monthly data from March 2005 to November 2006 were compared to the baseline average to create a departure from average statistic. Departures suggest that over 33% (4,714 km2) of the prestorm, coastal wetlands experienced a substantial decline in the density and vigor of vegetation by October 2005 (poststorm), mostly in the east and west regions, where landfalls of Hurricanes Katrina and Rita occurred. The percentage of area of persistent vegetation damage due to long-lasting formation of new open water was 91.8% in the east and 81.0% and 29.0% in the central and west regions, respectively. Although below average NDVI values were observed in most marsh communities through November 2006, recovery of vegetation was evident. Results indicated that impacts and recovery from large episodic disturbance events that influence multiple habitat types can be accurately determined using NDVI, especially when integrated with assessments of physical landscape changes and field verifications.

Monitoring vegetation response to episodic disturbance events by using multi-temporal vegetation indices

USGS Publications Warehouse

Steyer, Gregory D.; Couvillion, Brady R.; Barras, John A.

2013-01-01

Normalized Difference Vegetation Index (NDVI) derived from MODerate-resolution Imaging Spectroradiometer (MODIS) satellite imagery and land/water assessments from Landsat Thematic Mapper (TM) imagery were used to quantify the extent and severity of damage and subsequent recovery after Hurricanes Katrina and Rita of 2005 within the vegetation communities of Louisiana's coastal wetlands. Field data on species composition and total live cover were collected from 232 unique plots during multiple time periods to corroborate changes in NDVI values over time. Aprehurricane 5-year baseline time series clearly identified NDVI values by habitat type, suggesting the sensitivity of NDVI to assess and monitor phenological changes in coastal wetland habitats. Monthly data from March 2005 to November 2006 were compared to the baseline average to create a departure from average statistic. Departures suggest that over 33% (4,714 km2) of the prestorm, coastal wetlands experienced a substantial decline in the density and vigor of vegetation by October 2005 (poststorm), mostly in the east and west regions, where landfalls of Hurricanes Katrina and Rita occurred. The percentage of area of persistent vegetation damage due to long-lasting formation of new open water was 91.8% in the east and 81.0% and 29.0% in the central and west regions, respectively. Although below average NDVI values were observed in most marsh communities through November 2006, recovery of vegetation was evident. Results indicated that impacts and recovery from large episodic disturbance events that influence multiple habitat types can be accurately determined using NDVI, especially when integrated with assessments of physical landscape changes and field verifications.

Contrasting growth responses of dominant peatland plants to warming and vegetation composition.

PubMed

Walker, Tom N; Ward, Susan E; Ostle, Nicholas J; Bardgett, Richard D

2015-05-01

There is growing recognition that changes in vegetation composition can strongly influence peatland carbon cycling, with potential feedbacks to future climate. Nevertheless, despite accelerated climate and vegetation change in this ecosystem, the growth responses of peatland plant species to combined warming and vegetation change are unknown. Here, we used a field warming and vegetation removal experiment to test the hypothesis that dominant species from the three plant functional types present (dwarf-shrubs: Calluna vulgaris; graminoids: Eriophorum vaginatum; bryophytes: Sphagnum capillifolium) contrast in their growth responses to warming and the presence or absence of other plant functional types. Warming was accomplished using open top chambers, which raised air temperature by approximately 0.35 °C, and we measured air and soil microclimate as potential mechanisms through which both experimental factors could influence growth. We found that only Calluna growth increased with experimental warming (by 20%), whereas the presence of dwarf-shrubs and bryophytes increased growth of Sphagnum (46%) and Eriophorum (20%), respectively. Sphagnum growth was also negatively related to soil temperature, which was lower when dwarf-shrubs were present. Dwarf-shrubs may therefore promote Sphagnum growth by cooling the peat surface. Conversely, the effect of bryophyte presence on Eriophorum growth was not related to any change in microclimate, suggesting other factors play a role. In conclusion, our findings reveal contrasting abiotic and biotic controls over dominant peatland plant growth, suggesting that community composition and carbon cycling could be modified by simultaneous climate and vegetation change.

Pinon and juniper field guide: Asking the right questions to select appropriate management actions

Treesearch

R. J. Tausch; R. F. Miller; B. A. Roundy; J. C. Chambers

2009-01-01

Pinon-juniper woodlands are an important vegetation type in the Great Basin. Old-growth and open shrub savanna woodlands have been present over much of the last several hundred years. Strong evidence indicates these woodlands have experienced significant tree infilling and major expansion in their distribution since the late 1800s by encroaching into surrounding...

[Nitrogen fixation potential of biological soil crusts in Heidaigou open coal mine, Inner Mongolia, China].

PubMed

Zhang, Peng; Huang, Lei; Hu, Yi-gang; Zhao, Yang; Wu, Yong-chen

2016-02-01

Nitrogen limitation is common in terrestrial ecosystems, and it is particularly severe in damaged ecosystems in arid regions. Biological soil crusts (BSCs) , as a crucial component of recovered vegetation, play a vital role in nitrogen fixation during the ecological restoration processes of damaged ecosystems in arid and semi-arid regions. In this study, two dominant types of BSCs (i.e., cyanobacterial-algal crusts and moss crusts) that are widely distributed in the re-vegetated area of Heidaigou open pit coal mine were investigated. Samples were collected in the field and their nitrogenase activities (NA) were measured in the laboratory. The responses of NA to different hydro-thermal factors and the relationships between NA and herbs in addition to crust coverage were analyzed. The results indicated that BSCs under reconstructed vegetation at different succession stages, abandoned land and natural vegetation showed values of NA ranging from 9 to 150 µmol C2H4 . m-2 . h-1, and the NA value of algae crust (77 µmol C2H4 . m-2 . h-1) was markedly higher than that of moss crust (17 µmol C2H4 . m-2 . h-1). In the re-vegetated area, cyanobacterial-algal crust and moss crust under shrub-herb had higher NA values than those of crusts under arbor-shrnb and arbor-shrub-herb. The relationship between NA of the two BSCs and soil relative water content (10% - 100%) as well as culture temperature (5-45 °C) were of quadratic function. With elevated water content and cultural temperature, the NA values increased at the initial stage and then decreased, and reached the maximum value at 25 °C of cultural temperature and 60% or 80% of relative water content. The NA of cyanobacterial-algal crust had a significant quadratic function with herb coverage, as NA declined when herb coverage was higher than 20%. A significant negative correlation was observed between the NA of moss crusts and herb coverage. The NA values of the two types of BSCs had a significant positive correlation with crust coverage, since the NA was enhanced when the crust coverage was increased. We concluded that the different NA of the two BSCs in the re-vegetated area of Heidaigou open pit coal mine were caused by the composition of cryptograms. In addition, the differences of hydrothermal conditions and the composition of herb or crust coverage at different succession stages were also the contribution factors. Therefore, BSC construction and nitrogen fixation in re-vegetated areas is an important symbol for sustainable development in ecosystems.

Nest site selection by diamond-backed terrapins (Malaclemys terrapin) on a Mid-Atlantic Barrier Island

USGS Publications Warehouse

Mitchell, Joseph C.; Walls, Susan C.

2013-01-01

We scored 48 Malaclemys terrapin nests destroyed by raccoons on Fisherman Island, Virginia, for the presence or absence of tree canopy, shrub canopy, no canopy, bare sand, grass cover, and herbaceous cover. Significantly more nests than expected were found in the open with no vegetation cover and observed distances of predator-destroyed nests from the edge of the nearest habitat island of woody vegetation were significantly different from a normal distribution; most were placed near the island margin. Our results underscore the need to understand the influence of predator search behavior on terrapin nest survival in different habitat types.

Cattail invasion of sedge/grass meadows in Lake Ontario: Photointerpretation analysis of sixteen wetlands over five decades

USGS Publications Warehouse

Wilcox, D.A.; Kowalski, K.P.; Hoare, H.L.; Carlson, M.L.; Morgan, H.N.

2008-01-01

Photointerpretation studies were conducted to evaluate vegetation changes in wetlands of Lake Ontario and the upper St. Lawrence River associated with regulation of water levels since about 1960. The studies used photographs from 16 sites (four each from drowned river mouth, barrier beach, open embayment, and protected embayment wetlands) and spanned a period from the 1950s to 2001 at roughly decadal intervals. Meadow marsh was the most prominent vegetation type in most wetlands in the late 1950s when water levels had declined following high lake levels in the early 1950s. Meadow marsh increased at some sites in the mid-1960s in response to low lake levels and decreased at all sites in the late 1970s following a period of high lake levels. Typha increased at nearly all sites, except wave-exposed open embayments, in the 1970s. Meadow marsh continued to decrease and Typha to increase at most sites during sustained higher lake levels through the 1980s, 1990s, and into 2001. Most vegetation changes could be correlated with lake-level changes and with life-history strategies and physiological tolerances to water depth of prominent taxa. Analyses of GIS coverages demonstrated that much of the Typha invasion was landward into meadow marsh, largely by Typha x glauca. Lesser expansion toward open water included both T. x glauca and T. angustifolia. Although many models focus on the seed bank as a key component of vegetative change in wetlands, our results suggest that canopy-dominating, moisture-requiring Typha was able to invade meadow marsh at higher elevations because sustained higher lake levels allowed it to survive and overtake sedges and grasses that can tolerate periods of drier soil conditions.

Survey of Nitrate Ion Concentrations in Vegetables Cultivated in Plant Factories: Comparison with Open-Culture Vegetables.

PubMed

Oka, Yuka; Hirayama, Izumi; Yoshikawa, Mitsuhide; Yokoyama, Tomoko; Iida, Kenji; Iwakoshi, Katsushi; Suzuki, Ayana; Yanagihara, Midori; Segawa, Yukino; Kukimoto, Sonomi; Hamada, Humika; Matsuzawa, Satomi; Tabata, Setsuko; Sasamoto, Takeo

2017-01-01

A survey of nitrate-ion concentrations in plant-factory-cultured leafy vegetables was conducted. 344 samples of twenty-one varieties of raw leafy vegetables were examined using HPLC. The nitrate-ion concentrations in plant-factory-cultured leafy vegetables were found to be LOD-6,800 mg/kg. Furthermore, the average concentration values varied among different leafy vegetables. The average values for plant-factory-cultured leafy vegetables were higher than those of open-cultured leafy vegetables reported in previous studies, such as the values listed in the Standard Tables of Food Composition in Japan- 2015 - (Seventh revised edition). For some plant-factory-cultured leafy vegetables, such as salad spinach, the average values were above the maximum permissible levels of nitrate concentration in EC No 1258/2011; however, even when these plant-factory-cultured vegetables were routinely eaten, the intake of nitrate ions in humans did not exceed the ADI.

Habitat use by larval fishes in backwater lake of the upper Mississippi River

USGS Publications Warehouse

Dewey, M.R.; Jennings, C.A.

1992-01-01

Light traps were used to sample larval fishes in Lawrence Lake (Pool 8, upper Mississippi River) from late May through mid-August 1990. Catches differed considerably between vegetated sites and an adjacent open- water area and were highly variable among vegetated stations. Sunfishes (Lepomis spp.) dominated the vegetated sites. Brook silversides (Labidesthes sicculus), Cyprinidae ad gizzard shad (Dorosoma cepedianum) dominated catches at the open-water site. There was no difference in fish use of vegetated habitats near and far from the main channel of the Mississippi River. Taxonomic diversity was greatest at stations with emergent vegetation.

Effects of plant phenology and vertical height on accuracy of radio-telemetry locations

USGS Publications Warehouse

Grovenburg, Troy W.; Jacques, Christopher N.; Klaver, Robert W.; DePerno, Christopher S.; Lehman, Chad P.; Brinkman, Todd J.; Robling, Kevin A.; Rupp, Susan P.; Jenks, Jonathan A.

2013-01-01

The use of very high frequency (VHF) radio-telemetry remains wide-spread in studies of wildlife ecology and management. However, few studies have evaluated the influence of vegetative obstruction on accuracy in differing habitats with varying transmitter types and heights. Using adult and fawn collars at varying heights above the ground (0, 33, 66 and 100 cm) to simulate activities (bedded, feeding and standing) and ages (neonate, juvenile and adult) of deer Odocoileus spp., we collected 5,767 bearings and estimated 1,424 locations (28-30 for each of 48 subsamples) in three habitat types (pasture, grassland and forest), during two stages of vegetative growth (spring and late summer). Bearing error was approximately twice as large at a distance of 900 m for fawn (9.9°) than for adult deer collars (4.9°). Of 12 models developed to explain the variation in location error, the analysis of covariance model (HT*D + C*D + HT*TBA + C*TBA) containing interactions of height of collar above ground (HT), collar type (C), vertical height of understory vegetation (D) and tree basal area (TBA) was the best model (wi = 0.92) and explained ∼ 71% of the variation in location error. Location error was greater for both collar types at 0 and 33 cm above the ground compared to 66 and 100 cm above the ground; however, location error was less for adult than fawn collars. Vegetation metrics influenced location error, which increased with greater vertical height of understory vegetation and tree basal area. Further, interaction of vegetation metrics and categorical variables indicated significant effects on location error. Our results indicate that researchers need to consider study objectives, life history of the study animal, signal strength of collar (collar type), distance from transmitter to receiver, topographical changes in elevation, habitat composition and season when designing telemetry protocols. Bearing distances in forested habitat should be decreased (approximately 23% in our study) compared to bearing distances in open habitat to maintain a consistent bearing error across habitats. Additionally, we believe that field biologists monitoring neonate ungulates for habitat selection should rely on visual locations rather than using VHF-collars and triangulation.

Laboratory measurements of trace gas emissions from biomass burning of fuel types from the southeastern and southwestern United States

Treesearch

I. R. Burling; R. J. Yokelson; D. W. T. Griffith; T. J. Johnson; P. Veres; J. M. Roberts; C. Warneke; S. P. Urbanski; J. Reardon; D. R. Weise; W. M. Hao; J. de Gouw

2010-01-01

Vegetation commonly managed by prescribed burning was collected from five southeastern and southwestern US military bases and burned under controlled conditions at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The smoke emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared...

The Role of Personality Traits in Young Adult Fruit and Vegetable Consumption.

PubMed

Conner, Tamlin S; Thompson, Laura M; Knight, Rachel L; Flett, Jayde A M; Richardson, Aimee C; Brookie, Kate L

2017-01-01

This project investigated how individual differences in the big-five personality traits (neuroticism, extraversion, openness to experience, conscientiousness, and agreeableness) predicted plant-food consumption in young adults. A total of 1073 participants from two samples of young adults aged 17-25 reported their daily servings of fruits, vegetables, and two unhealthy foods for comparison purposes using an Internet daily diary for 21 or 13 days (micro-longitudinal, correlational design). Participants also completed the Neuroticism, Extraversion, Openness Five Factor Inventory (NEO-FFI) measure of personality, and demographic covariates including gender, age, ethnicity, and body mass index (BMI). Analyses used hierarchical regression to predict average daily fruit and vegetable consumption as separate dependent variables from the demographic covariates (step 1) and the five personality traits (step 2). Results showed that young adults higher in openness and extraversion, and to some extent conscientiousness, ate more fruits and vegetables than their less open, less extraverted, and less conscientious peers. Neuroticism and agreeableness were unrelated to fruit and vegetable consumption. These associations were unique to eating fruit and vegetables and mostly did not extend to unhealthy foods tested. Young adult women also ate more fruit and vegetables than young adult men. Results suggest that traits associated with greater intellect, curiosity, and social engagement (openness and extraversion), and to a lesser extent, discipline (conscientiousness) are associated with greater plant-food consumption in this population. Findings reinforce the importance of personality in establishing healthy dietary habits in young adulthood that could translate into better health outcomes later in life.

Beyond imperviousness: A statistical approach to identifying functional differences between development morphologies on variable source area-type response in urbanized watersheds

NASA Astrophysics Data System (ADS)

Lim, T. C.

2016-12-01

Empirical evidence has shown linkages between urbanization, hydrological regime change, and degradation of water quality and aquatic habitat. Percent imperviousness, has long been suggested as the dominant source of these negative changes. However, recent research identifying alternative pathways of runoff production at the watershed scale have called into question percent impervious surface area's primacy in urban runoff production compared to other aspects of urbanization including change in vegetative cover, imported water and water leakages, and the presence of drainage infrastructure. In this research I show how a robust statistical methodology can detect evidence of variable source area (VSA)-type hydrologic response associated with incremental hydraulic connectivity in watersheds. I then use logistic regression to explore how evidence of VSA-type response relates to the physical and meterological characteristics of the watershed. I find that impervious surface area is highly correlated with development, but does not add significant explanatory power beyond percent developed in predicting VSA-type response. Other aspects of development morphology, including percent developed open space and type of drainage infrastructure also do not add to the explanatory power of undeveloped land in predicting VSA-type response. Within only developed areas, the effect of developed open space was found to be more similar to that of total impervious area than to undeveloped land. These findings were consistent when tested across a national cross-section of urbanized watersheds, a higher resolution dataset of Baltimore Metropolitan Area watersheds, and a subsample of watersheds confirmed not to be served by combined sewer systems. These findings suggest that land development policies that focus on lot coverage should be revisited, and more focus should be placed on preserving native vegetation and soil conditions alongside development.

Analysis of change in marsh types of coastal Louisiana, 1978-2001

USGS Publications Warehouse

Linscombe, Robert G.; Hartley, Stephen B.

2011-01-01

Scientists and geographers have provided multiple datasets and maps to document temporal changes in vegetation types and land-water relationships in coastal Louisiana. Although these maps provide useful historical information, technological limitations prevented these and other mapping efforts from providing sufficiently detailed calculations of areal changes and shifts in habitat coverage. The current analysis of habitat change draws upon these past mapping efforts but is based on an advanced, geographic information system dataset that was created by using Landsat 5 Thematic Mapper imagery and digital orthophoto quarter quadrangles. The objective of building this dataset was to more specifically define land-water relationships over time in coastal Louisiana, and it provides the most detailed analysis of vegetation shifts to date. In the current study, we have attempted to explain these vegetation shifts by interpreting them in the context of rainfall records, data from the Palmer Drought Severity Index, and salinity data. During the 23 years we analyzed, total marsh acreage decreased, with conversion of marsh to open water. Furthermore, the general trend across coastal Louisiana was a shift to increasingly fresh marsh types. Although fresh marsh remained almost the same during the 1978-88 study period, there were greater increases during the 1988-2001 study periods. Intermediate marsh followed the same pattern, whereas brackish marsh showed a reverse (decreasing) pattern. Changes in saline (saltwater) marsh were minimal. Interpreting shifts in marsh vegetation types by using climate and salinity data provides better understanding of factors influencing these changes and, therefore, can improve our ability to make predictions about future marsh loss related to vegetation changes. Results of our study indicate that precipitation fluctuations prior to vegetation surveys impacted salinities differently across the coast. For example, a wet 6 months prior to the survey may or may not have made up for a dry period during the earlier 12 months. More research is needed to better understand rainfall periods and how they affect salinity changes. The ability to understand past dynamics and to anticipate future trends in vegetation change and related land loss in the coastal region of Louisiana is a vital part of ongoing and future efforts to conserve its critical wetland ecosystem. With the loss of marsh and resultant changes in hydrology, it is likely that changes in marsh type may show greater variation in the future, even if given only minor changes in precipitation levels.

Canopy openings and white-tailed deer influence the understory vegetation in mixed oak woodlots

Treesearch

Todd W. Bowersox; Gerald L. Storm; Walter M. Tzilkowski

1995-01-01

Effects of canopy opening and white-tailed deer on ground level vegetation are being assessed in south-central Pennsylvania. Herbaceous plants and woody seedlings are being monitored in three unevenaged, mixed oak woodlots at Gettysburg National Military Park. Canopy opening levels on 0.20 ha treatment units were closed (~100% canopy), small (50-60% canopy) and large (...

Latent heat exchange in the boreal and arctic biomes.

PubMed

Kasurinen, Ville; Alfredsen, Knut; Kolari, Pasi; Mammarella, Ivan; Alekseychik, Pavel; Rinne, Janne; Vesala, Timo; Bernier, Pierre; Boike, Julia; Langer, Moritz; Belelli Marchesini, Luca; van Huissteden, Ko; Dolman, Han; Sachs, Torsten; Ohta, Takeshi; Varlagin, Andrej; Rocha, Adrian; Arain, Altaf; Oechel, Walter; Lund, Magnus; Grelle, Achim; Lindroth, Anders; Black, Andy; Aurela, Mika; Laurila, Tuomas; Lohila, Annalea; Berninger, Frank

2014-11-01

In this study latent heat flux (λE) measurements made at 65 boreal and arctic eddy-covariance (EC) sites were analyses by using the Penman-Monteith equation. Sites were stratified into nine different ecosystem types: harvested and burnt forest areas, pine forests, spruce or fir forests, Douglas-fir forests, broadleaf deciduous forests, larch forests, wetlands, tundra and natural grasslands. The Penman-Monteith equation was calibrated with variable surface resistances against half-hourly eddy-covariance data and clear differences between ecosystem types were observed. Based on the modeled behavior of surface and aerodynamic resistances, surface resistance tightly control λE in most mature forests, while it had less importance in ecosystems having shorter vegetation like young or recently harvested forests, grasslands, wetlands and tundra. The parameters of the Penman-Monteith equation were clearly different for winter and summer conditions, indicating that phenological effects on surface resistance are important. We also compared the simulated λE of different ecosystem types under meteorological conditions at one site. Values of λE varied between 15% and 38% of the net radiation in the simulations with mean ecosystem parameters. In general, the simulations suggest that λE is higher from forested ecosystems than from grasslands, wetlands or tundra-type ecosystems. Forests showed usually a tighter stomatal control of λE as indicated by a pronounced sensitivity of surface resistance to atmospheric vapor pressure deficit. Nevertheless, the surface resistance of forests was lower than for open vegetation types including wetlands. Tundra and wetlands had higher surface resistances, which were less sensitive to vapor pressure deficits. The results indicate that the variation in surface resistance within and between different vegetation types might play a significant role in energy exchange between terrestrial ecosystems and atmosphere. These results suggest the need to take into account vegetation type and phenology in energy exchange modeling. © 2014 John Wiley & Sons Ltd.

Regional climate and vegetation response to orbital forcing within the mid-Pliocene Warm Period: A study using HadCM3

NASA Astrophysics Data System (ADS)

Prescott, C. L.; Dolan, A. M.; Haywood, A. M.; Hunter, S. J.; Tindall, J. C.

2018-02-01

Regional climate and environmental variability in response to orbital forcing during interglacial events within the mid-Piacenzian (Pliocene) Warm Period (mPWP; 3.264-3.025 Ma) has been rarely studied using climate and vegetation models. Here we use climate and vegetation model simulations to predict changes in regional vegetation patterns in response to orbital forcing for four different interglacial events within the mPWP (Marine Isotope Stages (MIS) G17, K1, KM3 and KM5c). The efficacy of model-predicted changes in regional vegetation is assessed by reference to selected high temporal resolution palaeobotanical studies that are theoretically capable of discerning vegetation patterns for the selected interglacial stages. Annual mean surface air temperatures for the studied interglacials are between 0.4 °C to 0.7 °C higher than a comparable Pliocene experiment using modern orbital parameters. Increased spring/summer and reduced autumn/winter insolation in the Northern Hemisphere during MIS G17, K1 and KM3 enhances seasonality in surface air temperature. The two most robust and notable regional responses to this in vegetation cover occur in North America and continental Eurasia, where forests are replaced by more open-types of vegetation (grasslands and shrubland). In these regions our model results appear to be inconsistent with local palaeobotanical data. The orbitally driven changes in seasonal temperature and precipitation lead to a 30% annual reduction in available deep soil moisture (2.0 m from surface), a critical parameter for forest growth, and subsequent reduction in the geographical coverage of forest-type vegetation; a phenomenon not seen in comparable simulations of Pliocene climate and vegetation run with a modern orbital configuration. Our results demonstrate the importance of examining model performance under a range of realistic orbital forcing scenarios within any defined time interval (e.g. mPWP). Additional orbitally resolved records of regional vegetation are needed to further examine the validity of model-predicted regional climate and vegetation responses in greater detail.

Propagule Pressure, Habitat Conditions and Clonal Integration Influence the Establishment and Growth of an Invasive Clonal Plant, Alternanthera philoxeroides.

PubMed

You, Wen-Hua; Han, Cui-Min; Fang, Long-Xiang; Du, Dao-Lin

2016-01-01

Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth, and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments) or low (one fragment) propagule pressure was established either in bare soil (open habitat) or dense native vegetation of Jussiaea repens (vegetative habitat), with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions.

Stable oxygen isotope analysis reveal vegetation influence on soil water movement and ecosystem water fluxes in a semi-arid oak woodland

NASA Astrophysics Data System (ADS)

Piayda, Arndt; Dubbert, Maren; Werner, Christiane; Cuntz, Matthias

2015-04-01

Mechanistically disentangling the role and function of vegetation within the hydrological cycle is one of the key questions in the interdisciplinary field of ecohydrology. The presence of vegetation can have various impacts on soil water relations: transpiration of active vegetation causes great water losses, rainfall is intercepted, soil evaporation can be reduced and infiltration, hydraulic redistribution and translatory flow might be altered. In drylands, covering around 40% of the global land surface, the carbon cycle is closely coupled to water availability due to (seasonal) droughts. Specifically savannah type ecosystems, which cover large areas worldwide, are, due to their bi-layered structure, very suitable to study the effects of distinct vegetation types on the ecosystem water cycle. Oxygen isotope signatures (δ18O) have been used to partition ecosystem evapotranspiration (ET ) because of the distinct isotopic compositions of water transpired by leaves relative to soil evaporated vapor. Recent developments in laser spectroscopy enable measurements of δ18O in the vapor phase with high temporal resolution in the field and bear a novel opportunity to trace water movement within the ecosystem. In the present study, the effects of distinct vegetation layers (i.e. trees and herbaceous vegetation) on soil water infiltration and redistribution as well as ecosystem water fluxes in a Mediterranean cork-oak woodland are disentangled. An irrigation experiment was carried out using δ18O labeled water to quantify the distinct effects of trees and herbaceous vegetation on 1) infiltration and redistribution of water in the soil profile and 2) to disentangle the effects of tree cover on the contribution of unproductive soil evaporation and understory transpiration to total ET . First results proof that stable δ18O isotopes measured onsite with laser spectroscopy is a valuable tool to trace water movement in the soil showing a much higher sensitivity than common TDR-type probes. It was possible to track soil water redistribution even beyond zero net water flux measured with TDR probes. Under shaded conditions beneath tree crowns, infiltration of precipitation reaches much deeper depths due to the limited radiation energy input and thus, reduced evaporative losses, compared to open areas between crowns. As a consequence, the isotopic enrichment back to initial conditions (as observed before the artificial precipitation event) was strongly delayed. Despite the higher water availability beneath tree crowns, transpiration of understory plants and soil evaporation rates were reduced compared to the open area due to the lack of energy. However, transpiration could be maintained much longer and at higher rates after the precipitation event then soil evaporation. These first results support previous findings at this site where a clear difference in understory plant community structure was observed. Beneath tree crowns, favorable water conditions enables a higher occurrence of grasses and nitrogen fixing forbs, whereas in between tree crowns drought adapted native species became dominant.

Woody vegetation and soil characteristics of residential forest patches and open spaces along an urban-to-rural gradient

Treesearch

Benjamin L. Reichert; Sharon R. Jean-Philippe; Christopher Oswalt; Jennifer Franklin; Mark Radosevich

2015-01-01

As the process of urbanization advances across the country, so does the importance of urban forests, which include both trees and the soils in which they grow. Soil microbial biomass, which plays a critical role in nutrient transformation in urban ecosystems, is affected by factors such as soil type and the availability of water, carbon, and nitrogen. The aim of this...

Effects of vegetation management in constructed wetland treatment cells on water quality and mosquito production

USGS Publications Warehouse

Thullen, J.S.; Sartoris, J.J.; Nelson, S.M.

2002-01-01

The impact of three vegetation management strategies on wetland treatment function and mosquito production was assessed in eight free water surface wetland test cells in southern California during 1998–1999. The effectiveness of the strategies to limit bulrush Schoenoplectus californicus culm density within the cells was also investigated. Removing accumulated emergent biomass and physically limiting the area in which vegetation could reestablish, significantly improved the ammonia–nitrogen removal efficiency of the wetland cells, which received an ammonia-dominated municipal wastewater effluent (average loading rate=9.88 kg/ha per day NH4-N). We determined that interspersing open water with emergent vegetation is critical for maintaining the wetland's treatment capability, particularly for systems high in NH4-N. Burning aboveground plant parts and thinning rhizomes only temporarily curtailed vegetation proliferation in shallow zones, whereas creating hummocks surrounded by deeper water successfully restricted the emergent vegetation to the shallower hummock areas. Since the hummock configuration kept open water areas interspersed throughout the stands of emergent vegetation, the strategy was also effective in reducing mosquito production. Decreasing vegetation biomass reduced mosquito refuge areas while increasing mosquito predator habitat. Therefore, the combined goals of water quality improvement and mosquito management were achieved by managing the spatial pattern of emergent vegetation to mimic an early successional growth stage, i.e. actively growing plants interspersed with open water.

Effects of vegetation management in constructed wetland treatment cells on water quality and mosquito production

USGS Publications Warehouse

Thullen, J.S.; Sartoris, J.J.; Walton, W.E.

2002-01-01

The impact of three vegetation management strategies on wetland treatment function and mosquito production was assessed in eight free water surface wetland test cells in southern California during 1998-1999. The effectiveness of the strategies to limit bulrush Schoenoplectus californicus culm density within the cells was also investigated. Removing accumulated emergent biomass and physically limiting the area in which vegetation could reestablish, significantly improved the ammonia - nitrogen removal efficiency of the wetland cells, which received an ammonia-dominated municipal wastewater effluent (average loading rate = 9.88 kg/ha per day NH4-N). We determined that interspersing open water with emergent vegetation is critical for maintaining the wetland's treatment capability, particularly for systems high in NH4-N. Burning aboveground plant parts and thinning rhizomes only temporarily curtailed vegetation proliferation in shallow zones, whereas creating hummocks surrounded by deeper water successfully restricted the emergent vegetation to the shallower hummock areas. Since the hummock configuration kept open water areas interspersed throughout the stands of emergent vegetation, the strategy was also effective in reducing mosquito production. Decreasing vegetation biomass reduced mosquito refuge areas while increasing mosquito predator habitat. Therefore, the combined goals of water quality improvement and mosquito management were achieved by managing the spatial pattern of emergent vegetation to mimic an early successional growth stage, i.e. actively growing plants interspersed with open water. ?? 2002 Elsevier Science B.V. All rights reserved.

Topography and vegetation alter soil nitrogen availability and loss in tropical and temperate ecosystems

NASA Astrophysics Data System (ADS)

Weintraub, S. R.

2016-12-01

A dominant paradigm in ecosystem ecology holds that nitrogen (N) cycles as an excess nutrient in old tropical landscapes but is a scarce, limiting resource in young, temperate ecosystems. However, recent work suggests that both biotic and abiotic state factors can promote unexpected patterns of N cycling across complex landscapes. Here, I present two case studies demonstrating how topography and vegetation shape patterns of N cycling and loss in heterogeneous terrain. In a geomorphically dynamic, high-diversity tropical rainforest, flat ridge tops display open N cycling, yet eroding hillslopes are surprisingly N-poor with multiple indicators implying conservative N cycling. Soil mineralogy indicates slope soils are less developed than adjacent flat ridge counterparts, and the accumulation of cosmogenic 10Be in surface soil suggests residence times are only half as long. Together, these observations suggest erosion resets soil development, with constant N-removal promoting tight N-cycling. Further, soil δ15N is negatively correlated with slope angle across the landscape, and mass balance modeling supports an increasing role for erosive N loss in steep regions. In a temperate montane landscape with lower physical erosion rates, vegetation interacts with hydro-topographic position to mediate local N dynamics. Upslope, forests display conservative N-cycling, yet in adjacent herbaceous areas, multiple indicators point toward an open N cycle. Downslope, both vegetation types show an increase in N-richness. In downslope forests, this is confined to the near-surface, stemming from higher foliar N content due to lateral N transport and uptake. In herbaceous sites, deeper vadose-zone N transport occurs but with no change in foliar N, implying differences in the degree of N limitation between vegetation types. In this landscape, soil nitrate leaching rates track N availability, though δ15N-NO3- does not suggest a similar pattern for gaseous losses, instead reflecting nitrification and/or transport dynamics. Pervasive human alteration of the N cycle underscores the need to unravel these state-factor controls on N availability and loss in order to predict and model ecosystem biogeochemical dynamics in the face of global change.

Determinants of Habitat Selection by Hatchling Australian Freshwater Crocodiles

PubMed Central

Somaweera, Ruchira; Webb, Jonathan K.; Shine, Richard

2011-01-01

Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle), most hatchling (<12-month-old) freshwater crocodiles (Crocodylus johnstoni) are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles) were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk. PMID:22163308

An expanded map of vegetation communities at Big Muddy National Fish and Wildlife Refuge

USGS Publications Warehouse

Struckhoff, Matthew A.

2013-01-01

In 2012, a map of vegetation communities on Big Muddy National Fish and Wildlife Refuge was expanded based on interpretation of aerial photographs and field data. National Agricultural Imagery Program aerial photographs were used to identify distinct communities on previously unmapped refuge units and newly acquired parcels. Newly mapped polygons were then visited to adjust map boundaries, classify communities according to the National Vegetation Classification System, and quantify the abundance of dominant species and non-native, invasive species of concern to the refuge and other resource management agencies along the Missouri River. The expanded map now covers 6,136 hectares representing 33 community types, including 6 previously unmapped types. The full map includes 1,113 polygons, of which 627 are new, 21 are updated from the 2009 mapping effort, and 465 are unchanged from 2009. Mortality of primarily cottonwood stems, because of growing-season floods between 2008 and 2011, has reduced foliar cover of woody stems and created more open wooded communities. In herbaceous communities, dominance by herbaceous old fields has increased due to the inclusion of refuge units dominated by lands in recent agricultural production in the expanded map. Wetland community abundance has increased slightly due to recent flooding.

Monitoring flooding and vegetation on seasonally inundated floodplains with multifrequency polarimetric synthetic aperture radar

NASA Astrophysics Data System (ADS)

Hess, Laura Lorraine

The ability of synthetic aperture radar to detect flooding and vegetation structure was evaluated for three seasonally inundated floodplain sites supporting a broad variety of wetland and upland vegetation types: two reaches of the Solimoes floodplain in the central Amazon, and the Magela Creek floodplain in Northern Territory, Australia. For each site, C- and L-band polarimetric Shuttle Imaging Radar-C (SIR-C) data was obtained at both high- and low-water stages. Inundation status and vegetation structure were documented simultaneous with the SIR-C acquisitions using low-altitude videography and ground measurements. SIR-C images were classified into cover states defined by vegetation physiognomy and presence of standing water, using a decision-tree model with backscattering coefficients at HH, VV, and HV polarizations as input variables. Classification accuracy was assessed using user's accuracy, producer's accuracy, and kappa coefficient for a test population of pixels. At all sites, both C- and L-band were necessary to accurately classify cover types with two dates. HH polarization was most. useful for distinguishing flooded from non-flooded vegetation (C-HH for macrophyte versus pasture, L-HH for flooded versus non-flooded forest), and cross-polarized L-band data provided the best separation between woody and non-woody vegetation. Increases in L-HH backscattering due to flooding were on the order of 3--4 dB for closed-canopy varzea and igapo forest, and 4--7 dB, for open Melaleuca woodland. The broad range of physiognomies and stand structures found in both herbaceous and woody wetland communities, combined with the variation in the amount of emergent canopy caused by water level fluctuations and phenologic changes, resulted in a large range in backscattering characteristics of wetland communities both within and between sites. High accuracies cannot be achieved for these communities using single-date, single-band, single-polarization data, particularly in the case of distinguishing flooded macrophyte from non-flooded forest vegetation. However, the large changes in backscattering caused by flooding make it possible to achieve good accuracies (>85%) using multi-temporal data. Where river stage records are available, SAR-based maps of inundation status on a series of dates can be linked to long-term stage data to define wetland habitat types based on flooding regime and low-water vegetation cover.

Evaluation of DOD Priority Species at Risk (SAR) and Applications for Remote Sensing

DTIC Science & Technology

2009-02-01

Species Type Common Name Scientific Name Fort McClellan AL fish coldwater darter Etheostoma ditrema Camp Shelby MS crustacean Camp Shelby burrowing...plant in the Aster family that exhibits mat-forming growth characteristics (Figure 15). B. tetraneuris in- habits barren, light colored shale and...vegetated areas within Fort Lewis, WA have the poten- tial to be mapped using high-resolution multispectral imagery. Other open (i.e., disturbed) habited

Using ALS and MODIS data to evaluate degradation in different forests types over the Xingu basin - Brazilian Amazon

NASA Astrophysics Data System (ADS)

Moura, Y.; Aragão, L. E.; Galvão, L. S.; Dalagnol, R.; Lyapustin, A.; Santos, E. G.; Espirito-Santo, F.

2017-12-01

Degradation of Amazon rainforests represents a vital threat to carbon storage, climate regulation and biodiversity; however its effect on tropical ecosystems is largely unknown. In this study we evaluate the effects of forest degradation on forest structure and functioning over the Xingu Basin in the Brazilian Amazon. The vegetation types in the area is dominated by Open Ombrophilous Forest (Asc), Semi-decidiuous Forest (Fse) and Dense Ombrophilous Forest (Dse). We used Airborne Laser Scanning (ALS) data together with time series of optical remote sensing images from the Moderate Resolution Imaging Spectroradiometer (MODIS) bi-directional corrected using the Multi-Angle Implementation for Atmospheric Correction (MAIAC). We derive time-series (2008 to 2016) of the Enhanced Vegetation Index (EVI) and Green-Red Normalized Difference (GRND) to analyze the dynamics of degraded areas with related changes in canopy structure and greenness values, respectively. Airborne ALS measurements showed the largest tree heights in the Dse class with values up to 40m tall. Asc and Fse vegetation types reached up to 30m and 25m in height, respectively. Differences in canopy structure were also evident from the analysis of canopy volume models (CVMs). Asc showed higher proportion of sunlit, as expected for open forest types. Fse showed gaps predominantly in lower height levels, and a higher overall proportion of shaded crown. Full canopy closure was reached at about15 m height for both Asc and Dse, and at about 20 m height for Fse. We also used a base map of degraded areas (available from Imazon - Instituto do Homen e Meio Ambiente da Amazônia) to follow these regions throughout time using EVI and GRND from MODIS. All three forest types displayed seasonal cycles. Notable differences in amplitude were detected during the periods when degradation occurred and both indexes showed a decrease in their response. However, there were marked differences in timing and amplitude depending on forest type. These responses were influenced by the spatial resolution of 1km of the MODIS images, limited the ability to observe small degraded regions. In conclusion, ASL together with optical remote sensing used in a straight multi-scale approach may contribute to understand the impacts of degradation in the structure and functioning of tropical forest.

Estuarine Vegetation at Rush Ranch Open Space Preserve, San Francisco Bay National Estuarine Research Reserve, California

USDA-ARS?s Scientific Manuscript database

The Rush Ranch Open Space Preserve (Rush Ranch) includes the largest remaining undiked tidal wetland within the Suisun Marsh region of the San Francisco Estuary. The brackish tidal wetlands grade into transitional vegetation and undeveloped grasslands of the Potrero Hills. We present analysis of ...

Tidal wetland vegetation and ecotone profiles: The Rush Ranch Open Space Preserve

USDA-ARS?s Scientific Manuscript database

The Rush Ranch Open Space Preserve (Rush Ranch) is a component site of the San Francisco Bay National Estuarine Research Reserve (SF Bay NERR) that includes one of the largest undiked tidal wetlands in the San Francisco Estuary. The brackish tidal wetlands grade into transitional vegetation and unde...

Vegetation Analysis and Land Use Land Cover Classification of Forest in Uttara Kannada District India Through Geo-Informatics Approach

NASA Astrophysics Data System (ADS)

Koppad, A. G.; Janagoudar, B. S.

2017-05-01

The study was conducted in Uttara Kannada districts during the year 2012-2014. The study area lies between 13.92° N to 15.52° N latitude and 74.08° E to 75.09° E longitude with an area of 10,215 km2. The Indian satellite IRS P6 LISS-III imageries were used to classify the land use land cover classes with ground truth data collected with GPS through supervised classification in ERDAS software. The land use and land cover classes identified were dense forest, horticulture plantation, sparse forest, forest plantation, open land and agriculture land. The dense forest covered an area of 63.32 % (6468.70 sq km) followed by agriculture 12.88 % (1315.31 sq. km), sparse forest 10.59 % (1081.37 sq. km), open land 6.09 % (622.37 sq. km), horticulture plantation and least was forest plantation (1.07 %). Settlement, stony land and water body together cover about 4.26 percent of the area. The study indicated that the aspect and altitude influenced the forest types and vegetation pattern. The NDVI map was prepared which indicated that healthy vegetation is represented by high NDVI values between 0.1 and 1. The non-vegetated features such as water bodies, settlement, and stony land indicated less than 0.1 values. The decrease in forest area in some places was due to anthropogenic activities. The thematic map of land use land cover classes was prepared using Arc GIS Software.

Phenotypic variation and vulnerability to predation in juvenile bluegill sunfish (Lepomis macrochirus)

USGS Publications Warehouse

Chipps, S.R.; Dunbar, J.A.; Wahl, David H.

2004-01-01

Bluegill sunfish (Lepomis macrochirus) are known to diversify into two forms specialized for foraging on either limnetic or littoral prey. Because juvenile bluegills seek vegetative cover in the presence of largemouth bass (Micropterus salmoides) predators, natural selection should favor the littoral body design at size ranges most vulnerable to predation. Yet within bluegill populations, both limnetic and littoral forms occur where vegetation and predators are present. While adaptive for foraging in different environments, does habitat-linked phenotypic variation also influence predator evasiveness for juvenile bluegills? We evaluate this question by quantifying susceptibility to predation for two groups of morphologically distinct bluegills; a limnetic form characteristic of bluegills inhabiting open water areas (limnetic bluegill) and a littoral form characteristic of bluegills inhabiting dense vegetation (littoral bluegill). In a series of predation trials, we found that bluegill behaviors differed in open water habitat but not in simulated vegetation. In open water habitat, limnetic bluegills formed more dense shoaling aggregations, maintained a larger distance from the predator, and required longer amounts of time to capture than littoral bluegill. When provided with simulated vegetation, largemouth bass spent longer amounts of time pursuing littoral bluegill and captured significantly fewer littoral bluegills than limnetic fish. Hence, morphological and behavioral variation in bluegills was linked to differential susceptibility to predation in open water and vegetated environments. Combined with previous studies, these findings show that morphological and behavioral adaptations enhance both foraging performance and predator evasiveness in different lake habitats.

Distinctiveness, use, and value of midwestern oak savannas and woodlands as avian habitats

USGS Publications Warehouse

Grundel, R.; Pavlovic, N.B.

2007-01-01

Oak savannas and woodlands historically covered millions of hectares in the midwestern United States but are rare today. We evaluated the ecological distinctiveness and conservation value of savannas and woodlands by examining bird distributions across a fire-maintained woody-vegetation gradient in northwest Indiana encompassing five habitats—open habitats with low canopy cover, savannas, woodlands, scrublands, and forests—during migration, breeding, and overwintering. Savannas and woodlands were significantly different in overall bird species composition from open and forest habitats but were often intermediate between open and forest in guild densities. Few bird species were consistently and highly concentrated in savannas or woodlands, and the Red-headed Woodpecker (Melanerpes erythrocephalus) was the only species significantly more abundant in savannas and woodlands than in open, scrub, and forest habitats. Fire frequency over a 15-year interval was a significant predictor of bird community composition and was positively related to species diversity, spring transient migrant density, and density of the most threatened species. Each habitat type had characteristics potentially important for avian conservation. Scrub had the highest density of transient migrants, which suggests it plays an important role as migration stopover habitat. More species were significantly concentrated in open or forest habitats than in the other habitats. Lack of species concentration and intermediate community composition suggested that birds experienced savannas and woodlands more as ecotones than as habitats distinct from forests or grasslands. However, this intermediate character can benefit conservation, as evidenced by savannas and woodlands having the highest density of the most threatened species along this woody-vegetation gradient.

Characterising Vegetation Structural and Functional Differences Across Australian Ecosystems From a Network of Terrestrial Laser Scanning Survey Sites and Airborne and Satellite Image Archives

NASA Astrophysics Data System (ADS)

Phinn, S. R.; Armston, J.; Scarth, P.; Johansen, K.; Schaefer, M.; Suarez, L.; Soto-Berelov, M.; Muir, J.; Woodgate, W.; Jones, S.; Held, A. A.

2015-12-01

Vegetation structural information is critical for environmental monitoring, management and compliance assessment. In this context we refer to vegetation structural properties as vertical, horizontal and volumetric dimensions, including: canopy height; amount and distribution of vegetation by height; foliage projective cover (FPC); leaf area index (LAI); and above ground biomass. Our aim was to determine if there were significant differences between vegetation structural properties across 11 ecosystem types in Australia as measured by terrestrial laser scanner (TLS) structure metrics. The ecosystems sampled included: mesophyll vineforest, wet-dry tropical savannah, mallee woodland, subtropical eucalypt forest, mulga woodland/grassland, wet eucalypt forest, dry eucalypt forest, tall and wet eucalypt forest, and desert grassland/shrublands. Canopy height, plant area-height profiles and LAI were calculated from consistently processed TLS data using Australia's Terrestrial Ecosystem Research Network's (TERN) Supersites by the TERN AusCover remote sensing field teams from 2012-2015. The Supersites were sampled using standardised field protocols within a core set of 1 ha plots as part of a 5 km x 5 km uniform area using a RIEGL-VZ400 waveform recording TLS. Four to seven scans were completed per plot, with one centre point and then at 25 m away from the centre point along transect lines at 0o, 60o and 240o. Individual foliage profiles were sensitive to spatial variation in the distribution of plant materials. Significant differences were visible between each of the vegetation communities assessed when aggregated to plot and ecosystem type scales. Several of the communities exhibited simple profiles with either grass and shrubs (e.g. desert grassland) or grass and trees (e.g. mallee woodland). Others had multiple vegetation forms at different heights, contributing to the profile (e.g. wet eucalypt forest). The TLS data provide significantly more detail about the relative vertical and horizontal distribution of plant materials. TLS data are providing a step change in satellite image based vegetation mapping, and refining our knowledge of vegetation structure and its phenological variability. Open access plot scale TLS measurements are available through the TERN Auscover data portal.

Alluvial deposits and plant distribution in an Amazonian lowland megafan

NASA Astrophysics Data System (ADS)

Zani, H.; Rossetti, D.; Cremon; Cohen, M.; Pessenda, L. C.

2012-12-01

A large volume of sandy alluvial deposits (> 1000 km2) characterizes a flat wetland in northern Amazonia. These have been recently described as the sedimentary record of a megafan system, which have a distinct triangular shape produced by highly migratory distributary rivers. The vegetation map suggests that this megafan is dominated by open vegetation in sharp contact with the surround rainforest. Understanding the relationship between geomorphological processes and vegetation distribution is crucial to decipher and conserve the biodiversity in this Amazonian ecosystem. In this study we interpret plant dynamics over time, and investigate its potential control by sedimentary processes during landscape evolution. The study area is located in the Viruá National Park. Two field campaigns were undertaken in the dry seasons of 2010 and 2011 and the sampling sites were selected by combining accessibility and representativeness. Vegetation contrasts were recorded along a transect in the medial section of the Viruá megafan. Due to the absence of outcrops, samples were extracted using a core device, which allowed sampling up to a depth of 7.5 m. All cores were opened and described in the field, with 5 cm3 samples collected at 20 cm intervals. The δ13C of organic matter was used as a proxy to distinguish between C3 and C4 plant communities. The chronology was established based on radiocarbon dating. The results suggest that the cores from forested areas show the most depleted values of δ13C, ranging from -32.16 to -27.28‰. The δ13C curve in these areas displays typical C3 land plant values for the entire record, which covers most of the Holocene. This finding indicates that either the vegetation remained stable over time or the sites were dominated by aquatic environments with freshwater plants before forest establishment. The cores from the open vegetation areas show a progressive upward enrichment in δ13C values, which range from -28.50 to -19.59‰. This trend is more pronounced after de mid-Holocene, suggesting that the open vegetation, represented mostly by C4 land plants, evolved only more recently. Based on our isotope data, a model is proposed taking into account the influence of sedimentary dynamics on the modern pattern of plan distribution. The establishment of open vegetation occurred at different times depending on location over the megafan area, varying from around 3,000 to 6,400 cal yrs BP. As sedimentation took place, areas located far from the surrounding rainforest were prone to inputs of organic matter derived from open vegetation, whereas the contribution of organic matter derived from arboreous vegetation increases toward the areas located closer to the rainforest. In general, open vegetation is constrained to depositional sites that remained active until relatively recent Holocene times, while surrounding areas with a relatively older geological history are covered by dense forest. The results presented here consist in a striking example of the influence of sedimentary processes during the Late Pleistocene-Holocene on the development of modern plants of this Amazonian lowland.

Vegetable Grafting: The Implications of a Growing Agronomic Imperative for Vegetable Fruit Quality and Nutritive Value

PubMed Central

Kyriacou, Marios C.; Rouphael, Youssef; Colla, Giuseppe; Zrenner, Rita; Schwarz, Dietmar

2017-01-01

Grafting has become an imperative for intensive vegetable production since chlorofluorocarbon-based soil fumigants were banned from use on grounds of environmental protection. Compelled by this development, research into rootstock–scion interaction has broadened the potential applications of grafting in the vegetable industry beyond aspects of soil phytopathology. Grafting has been increasingly tapped for cultivation under adverse environs posing abiotic and biotic stresses to vegetable crops, thus enabling expansion of commercial production onto otherwise under-exploited land. Vigorous rootstocks have been employed not only in the open field but also under protected cultivation where increase in productivity improves distribution of infrastructural and energy costs. Applications of grafting have expanded mainly in two families: the Cucurbitaceae and the Solanaceae, both of which comprise major vegetable crops. As the main drives behind the expansion of vegetable grafting have been the resistance to soilborne pathogens, tolerance to abiotic stresses and increase in yields, rootstock selection and breeding have accordingly conformed to the prevailing demand for improving productivity, arguably at the expense of fruit quality. It is, however, compelling to assess the qualitative implications of this growing agronomic practice for human nutrition. Problems of impaired vegetable fruit quality have not infrequently been associated with the practice of grafting. Accordingly, the aim of the current review is to reassess how the practice of grafting and the prevalence of particular types of commercial rootstocks influence vegetable fruit quality and, partly, storability. Physical, sensorial and bioactive aspects of quality are examined with respect to grafting for watermelon, melon, cucumber, tomato, eggplant, and pepper. The physiological mechanisms at play which mediate rootstock effects on scion performance are discussed in interpreting the implications of grafting for the configuration of vegetable fruit physicochemical quality and nutritive value. PMID:28553298

Possible causes of Arctic Tundra Vegetation Productivity Declines

NASA Astrophysics Data System (ADS)

Bhatt, U. S.; Walker, D. A.; Raynolds, M. K.; Bieniek, P.; Epstein, H. E.; Comiso, J. C.; Pinzon, J. E.; Tucker, C. J.

2017-12-01

Three decades of remotely sensed Normalized Difference Vegetation Index (NDVI) data document an overall increase in Arctic tundra vegetation greenness but the trends display considerable spatial variability. Pan-Arctic tundra vegetation greening is associated with increases in summer warmth that are, in large-part, driven by summer sea-ice retreat along Arctic coasts. Trends covering the period 1982-2016 are overall positive for summer open water, Summer Warmth Index (SWI, the sum of the degree months above zero from May-August), MaxNDVI (peak NDVI) and time integrated NDVI (TI-NDVI, sum of biweekly NDVI above 0.05 from May-September). Upon closer examination, it is clear that not all regions have positive trends, for example, there is an area of cooling in western Eurasia, which is broadly co-located with maxNDVI and TI-NDVI declines. While sea ice decline has continued over the satellite record, summer landsurface temperatures and vegetation productivity measures have not simply increased. Regional differences between warming and greening trends suggest that it is likely that multiple processes influence vegetation productivity beyond secular greening with increased summer warmth. This paper will present Pan-Arctic and regional analyses of the NDVI data in the context of climate drivers. Other possible drivers of vegetation productivity decline will be discussed such as increased standing water, delayed spring snow-melt, and winter thaw events. The status and limitations of data sets and modeling needed to advance our understanding of tundra vegetation productivity will be summarized and will serve as a starting point for planning the next steps in this topic. Methodical multi-disciplinary synthesis research that jointly considers vegetation type, permafrost conditions, altitude, as well as climate factors such as temperature, heat and moisture transport, and timing of snowfall and spring snowmelt is needed to better understand recent tundra vegetation productivity declines.

Vegetation mapping of the Mond Protected Area of Bushehr Province (south-west Iran).

PubMed

Mehrabian, Ahmadreza; Naqinezhad, Alireza; Mahiny, Abdolrassoul Salman; Mostafavi, Hossein; Liaghati, Homan; Kouchekzadeh, Mohsen

2009-03-01

Arid regions of the world occupy up to 35% of the earth's surface, the basis of various definitions of climatic conditions, vegetation types or potential for food production. Due to their high ecological value, monitoring of arid regions is necessary and modern vegetation studies can help in the conservation and management of these areas. The use of remote sensing for mapping of desert vegetation is difficult due to mixing of the spectral reflectance of bright desert soils with the weak spectral response of sparse vegetation. We studied the vegetation types in the semiarid to arid region of Mond Protected Area, south-west Iran, based on unsupervised classification of the Spot XS bands and then produced updated maps. Sixteen map units covering 12 vegetation types were recognized in the area based on both field works and satellite mapping. Halocnemum strobilaceum and Suaeda fruticosa vegetation types were the dominant types and Ephedra foliata, Salicornia europaea-Suaeda heterophylla vegetation types were the smallest. Vegetation coverage decreased sharply with the increase in salinity towards the coastal areas of the Persian Gulf. The highest vegetation coverage belonged to the riparian vegetation along the Mond River, which represents the northern boundary of the protected area. The location of vegetation types was studied on the separate soil and habitat diversity maps of the study area, which helped in final refinements of the vegetation map produced.

Polycyclic aromatic hydrocarbons (PAHs) in soils and vegetation near an e-waste recycling site in South China: concentration, distribution, source, and risk assessment.

PubMed

Wang, Yan; Tian, Zhongjing; Zhu, Haolin; Cheng, Zhineng; Kang, Meiling; Luo, Chunling; Li, Jun; Zhang, Gan

2012-11-15

This study determined the concentrations of PAHs generated from e-waste recycling activities and their potential impacts on soil, vegetation, and human health. The total PAH concentrations in soils and plants ranged from 127 to 10,600 and 199 to 2420 ng/g, respectively. Samples from an e-waste burning site had higher PAH concentrations than samples from adjacent locations. The PAHs in plants varied with plant species and tissue, and Lactuca sativa L. contained the highest PAHs of all the vegetable species. Various land use types showed different PAH concentrations in soils, with vegetable fields showing higher concentrations than paddy fields. Low molecular weight PAHs, such as phenanthrene, were the predominant congeners in soils, whereas high molecular weight PAHs, such as fluoranthene, pyrene, and benzo[a]anthracene, were enriched in plants relative to soils. Dissimilar PAH profiles in soil and the corresponding vegetation indicated that the uptake of PAHs by plants was selective. A source analysis showed that the contamination by PAHs originated primarily from the open burning of e-waste. The total daily intakes of PAHs and carcinogenic PAHs through vegetables at the e-waste dismantling site were estimated to be 279 and 108 ng/kg/d, respectively, indicating that the consumption of vegetables grown near e-waste recycling sites is risky and should be completely avoided. Copyright © 2012 Elsevier B.V. All rights reserved.

Differences in hydrological responses for different vegetation types on a steep slope on the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Duan, Liangxia; Huang, Mingbin; Zhang, Luodan

2016-06-01

Extensive vegetation restoration practices have been implemented to control soil erosion on the Loess Plateau, China. However, no strict guidelines are available to determine the most suitable plant species for vegetation restoration within a given area. The objective of this study was to quantify the changes of each component (soil water storage, surface runoff, and actual evapotranspiration) of a water balance model and soil loss over time under eight different vegetation types, and to further determine the optimal vegetation type for soil and water conservation and sustainable ecological restoration on the steep slopes (>25°) on the Loess Plateau. The results indicated that vegetation type substantially affected soil water storage and that the greatest soil water storage in both the shallow (0-2 m) and the deep soil layers (2-5 m) occurred under Bothriochloa ischaemum L. (BOI). Vegetation type also affected surface runoff and soil losses. The most effective vegetation types for reducing soil erosion were BOI and Sea-buckthorn (Hippophae rhamnoides L.), while Chinese pine (Pinus tabulaeformis Carr.) and Chinese pine + Black locust (Robinia pseudoacacia L.) were the most ineffective types. Soil water dynamics and evapotranspiration varied considerably among the different vegetation types. A soil water surplus was only found under BOI, while insufficient water replenishment existed under the other seven vegetation types. The higher water consumption rates of the seven vegetation types could result in soil desiccation, which could lead to severe water stresses that would adversely affect plant growth. This study suggested that both vegetation type and its effect on controlling soil erosion should be considered when implementing vegetation restoration and that BOI should be highly recommended for vegetation restoration on the steep slopes of the Loess Plateau. A similar approach to the one used in this study could be applied to other regions of the world confronted by the same problems of water scarcity along with the need for vegetation restoration.

Ecological relationships of fauna and flora on a pre-law coal surface-mined area in Perry County, Illinois

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, J.R.

1986-01-01

Pre-law coal surface-mined lands in Pyramid State Park, Perry County, Illinois, were examined 1976-1980 to determine changes in fauna and flora from that on the area in 1954-1960. Vegetative development on naturally revegetated spoils reflected diverse habitat conditions with interspersion of cover types; some of oldest spoils displayed inhibited succession while others exhibited early flood plain forest development. Ground and overstory species richness and overstory density increased since mid 1950's and ground cover domination by therophytes in 1954-1956 shifted to phanerophytes and hemicryptophytes in 1976-1978. Thirty vegetative compositional and structural parameters indicated that ground cover was limited by subcanopy rathermore » than large scattered trees. Aquatic vegetation communities developed but hydrosphere was not well represented; emergent vegetation was limited by morphology of basins. Although isolated sites exhibited deleterious conditions, vegetation was not generally inhibited by physico-chemical factors. The 29 mammals reflected an increase in species richness. Abundance of early successional forms decreased while occupants of shrub/forest increased. Past habitat enhancement influenced wildlife distribution; and plantations attracted woodland fauna. Leveled spoil crests, valleys and clearings with fescue retarded succession and provided open areas and edges for others.« less

Multiangular Contributions for Discriminate Seasonal Structural Changes in the Amazon Rainforest Using MODIS MAIAC Data

NASA Astrophysics Data System (ADS)

Moura, Y. M.; Hilker, T.; Galvão, L. S.; Santos, J. R.; Lyapustin, A.; Sousa, C. H. R. D.; McAdam, E.

2014-12-01

The sensitivity of the Amazon rainforests to climate change has received great attention by the scientific community due to the important role that this vegetation plays in the global carbon, water and energy cycle. The spatial and temporal variability of tropical forests across Amazonia, and their phenological, ecological and edaphic cycles are still poorly understood. The objective of this work was to infer seasonal and spatial variability of forest structure in the Brazilian Amazon based on anisotropy of multi-angle satellite observations. We used observations from the Moderate Resolution Imaging Spectroradiometer (MODIS/Terra and Aqua) processed by a new Multi-Angle Implementation Atmospheric Correction Algorithm (MAIAC) to investigate how multi-angular spectral response from satellite imagery can be used to analyze structural variability of Amazon rainforests. We calculated differences acquired from forward and backscatter reflectance by modeling the bi-directional reflectance distribution function to infer seasonal and spatial changes in vegetation structure. Changes in anisotropy were larger during the dry season than during the wet season, suggesting intra-annual changes in vegetation structure and density. However, there were marked differences in timing and amplitude depending on forest type. For instance differences between reflectance hotspot and darkspot showed more anisotropy in the open Ombrophilous forest than in the dense Ombrophilous forest. Our results show that multi-angle data can be useful for analyzing structural differences in various forest types and for discriminating different seasonal effects within the Amazon basin. Also, multi-angle data could help solve uncertainties about sensitivity of different tropical forest types to light versus rainfall. In conclusion, multi-angular information, as expressed by the anisotropy of spectral reflectance, may complement conventional studies and provide significant improvements over approaches that are based on vegetation indices alone.

[Effects of road construction on regional vegetation types].

PubMed

Liu, Shi-Liang; Liu, Qi; Wang, Cong; Yang, Jue-Jie; Deng, Li

2013-05-01

As a regional artificial disturbance component, road exerts great effects on vegetation types, and plays a substantial role in defining vegetation distribution to a certain extent. Aiming at the tropical rainforest degradation and artificial forest expansion in Yunnan Province of Southwest China, this paper analyzed the effects of road network extension on regional vegetation types. In the Province, different classes of roads had different effects on the vegetation types, but no obvious regularity was observed in the effects on the patch areas of different vegetation types due to the great variations of road length and affected distance. However, the vegetation patch number was more affected by lower class roads because of their wide distribution. As for different vegetation types, the vegetations on cultivated land were most affected by roads, followed by Castanopsis hystrix and Schima wallichii forests. Road network formation contributed most to the vegetation fragmentation, and there existed significant correlations between the human disturbance factors including village- and road distributions.

Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years

PubMed Central

Tng, David Y P; Murphy, Brett P; Weber, Ellen; Sanders, Gregor; Williamson, Grant J; Kemp, Jeanette; Bowman, David M J S

2012-01-01

Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of northeastern Queensland, Australia, taken in the 1950s and 2008, to determine if changes in rain forest extent match those reported for the Australian monsoon tropics using similar techniques. Mapping of the 1950s aerial photography showed that of the combined study area (64,430 ha), 63% was classified as eucalypt forests/woodland and 37% as rain forest. Our mapping revealed that although most boundaries remained stable, there was a net increase of 732 ha of the original rain forest area over the study period, and negligible conversion of rain forest to eucalypt forest/woodland. Statistical modeling, controlling for spatial autocorrelation, indicated distance from preexisting rain forest as the strongest determinant of rain forest expansion. Margin extension had a mean rate across the five sites of 0.6 m per decade. Expansion was greater in tall open forest types but also occurred in shorter, more flammable woodland vegetation types. No correlations were detected with other local variables (aspect, elevation, geology, topography, drainage). Using a geographically weighted mean rate of rain forest margin extension across the whole region, we predict that over 25% of tall open forest (a forest type of high conservation significance) would still remain after 2000 years of rain forest expansion. This slow replacement is due to the convoluted nature of the rain forest boundary and the irregular shape of the tall open forest patches. Our analyses point to the increased concentration of atmospheric CO2 as the most likely global driver of indiscriminate rain forest expansion occurring in northeastern Australia, by increasing tree growth and thereby overriding the effects of fire disturbance. PMID:22408724

Shelter Index and a simple wind speed parameter to characterize vegetation control of sand transport threshold and Flu

NASA Astrophysics Data System (ADS)

Gillies, J. A.; Nield, J. M.; Nickling, W. G.; Furtak-Cole, E.

2014-12-01

Wind erosion and dust emissions occur in many dryland environments from a range of surfaces with different types and amounts of vegetation. Understanding how vegetation modulates these processes remains a research challenge. Here we present results from a study that examines the relationship between an index of shelter (SI=distance from a point to the nearest upwind vegetation/vegetation height) and particle threshold expressed as the ratio of wind speed measured at 0.45 times the mean plant height divided by the wind speed at 17 m when saltation commences, and saltation flux. The results are used to evaluate SI as a parameter to characterize the influence of vegetation on local winds and sediment transport conditions. Wind speed, wind direction, saltation activity and point saltation flux were measured at 35 locations in defined test areas (~13,000 m2) in two vegetation communities: mature streets of mesquite covered nebkhas and incipient nebkhas dominated by low mesquite plants. Measurement positions represent the most open areas, and hence those places most susceptible to wind erosion among the vegetation elements. Shelter index was calculated for each measurement position for each 10° wind direction bin using digital elevation models for each site acquired using terrestrial laser scanning. SI can show the susceptibility to wind erosion at different time scales, i.e., event, seasonal, or annual, but in a supply-limited system it can fail to define actual flux amounts due to a lack of knowledge of the distribution of sediment across the surface of interest with respect to the patterns of SI.

Evaluating the role of green infrastructures on near-road pollutant dispersion and removal: Modelling and measurement.

PubMed

Morakinyo, Tobi Eniolu; Lam, Yun Fat; Hao, Song

2016-11-01

To enhance the quality of human life in a rapidly urbanized world plagued with high transportation, the masterful contribution of improved urban and local air quality cannot be overemphasized. In order to reduce human exposure to near-road air pollution, several approaches including the installation of roadside structural barriers especially in open street areas, such as city entrances are being applied. In the present study, the air quality around real world and idealized green infrastructures was investigated by means of numerical simulation and a short field measurement campaign. Fair agreement was found between ENVI-met modelled and measured particulate matter's concentration data around a realistic vegetation barrier indicating a fair representation of reality in the model. Several numerical experiments were conducted to investigate the influence of barrier type (vegetation/hedge and green wall) and dimensions on near-road air quality. The results show different horizontal/vertical patterns and magnitudes of upwind and downwind relative concentration (with and without a barrier) depending on wind condition, barrier type and dimension. Furthermore, an integrated dispersion-deposition approach was employed to assess the impact on air quality of near-road vegetation barrier. At last, recommendations to city and urban planners on the implementation of roadside structural barriers were made. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impacts of manganese mining activity on the environment: interactions among soil, plants, and arbuscular mycorrhiza.

PubMed

Rivera-Becerril, Facundo; Juárez-Vázquez, Lucía V; Hernández-Cervantes, Saúl C; Acevedo-Sandoval, Otilio A; Vela-Correa, Gilberto; Cruz-Chávez, Enrique; Moreno-Espíndola, Iván P; Esquivel-Herrera, Alfonso; de León-González, Fernando

2013-02-01

The mining district of Molango in the Hidalgo State, Mexico, possesses one of the largest deposits of manganese (Mn) ore in the world. This research assessed the impacts of Mn mining activity on the environment, particularly the interactions among soil, plants, and arbuscular mycorrhiza (AM) at a location under the influence of an open Mn mine. Soils and plants from three sites (soil under maize, soil under native vegetation, and mine wastes with some vegetation) were analyzed. Available Mn in both soil types and mine wastes did not reach toxic levels. Samples of the two soil types were similar regarding physical, chemical, and biological properties; mine wastes were characterized by poor physical structure, nutrient deficiencies, and a decreased number of arbuscular mycorrhizal fungi (AMF) spores. Tissues of six plant species accumulated Mn at normal levels. AM was absent in the five plant species (Ambrosia psilostachya, Chenopodium ambrosoides, Cynodon dactylon, Polygonum hydropiperoides, and Wigandia urens) established in mine wastes, which was consistent with the significantly lower number of AMF spores compared with both soil types. A. psilostachya (native vegetation) and Zea mays showed mycorrhizal colonization in their root systems; in the former, AM significantly decreased Mn uptake. The following was concluded: (1) soils, mine wastes, and plant tissues did not accumulate Mn at toxic levels; (2) despite its poor physical structure and nutrient deficiencies, the mine waste site was colonized by at least five plant species; (3) plants growing in both soil types interacted with AMF; and (4) mycorrhizal colonization of A. psilostachya influenced low uptake of Mn by plant tissues.

An evaluation of thematic mapper simulator data for the geobotanical discrimination of rock types in Southwest Oregon

NASA Technical Reports Server (NTRS)

Weinstock, K. J.; Morrissey, L. A.

1984-01-01

Rock type identification may be assisted by the use of remote sensing of associated vegetation, particularly in areas of dense vegetative cover where surface materials are not imaged directly by the sensor. The geobotanical discrimination of ultramafic parent materials was investigated and analytical techniques for lithologic mapping and mineral exploration were developed. The utility of remotely sensed data to discriminate vegetation types associated with ultramafic parent materials in a study area in southwest Oregon were evaluated. A number of specific objectives were identified, which include: (1) establishment of the association between vegetation and rock types; (2) examination of the spectral separability of vegetation types associated with rock types; (3) determination of the contribution of each TMS band for discriminating vegetation associated with rock types and (4) comparison of analytical techniques for spectrally classifying vegetation.

Comparing the response of birds and butterflies to vegetation-based mountain ecotones using boundary detection approaches.

PubMed

Kent, Rafi; Levanoni, Oded; Banker, Eran; Pe'er, Guy; Kark, Salit

2013-01-01

Mountains provide an opportunity to examine changes in biodiversity across environmental gradients and areas of transition (ecotones). Mountain ecotones separate vegetation belts. Here, we aimed to examine whether transition areas for birds and butterflies spatially correspond with ecotones between three previously described altitudinal vegetation belts on Mt. Hermon, northern Israel. These include the Mediterranean Maquis, xero-montane open forest and Tragacanthic mountain steppe vegetation belts. We sampled the abundance of bird and butterfly species in 34 sampling locations along an elevational gradient between 500 and 2200 m. We applied wombling, a boundary-detection technique, which detects rapid changes in a continuous variable, in order to locate the transition areas for bird and butterfly communities and compare the location of these areas with the location of vegetation belts as described in earlier studies of Mt. Hermon. We found some correspondence between the areas of transition of both bird and butterfly communities and the ecotones between vegetation belts. For birds and butterflies, important transitions occurred at the lower vegetation ecotone between Mediterranean maquis and the xero-montane open forest vegetation belts, and between the xero-montane open forest and the mountain steppe Tragacanthic belts. While patterns of species turnover with elevation were similar for birds and butterflies, the change in species richness and diversity with elevation differed substantially between the two taxa. Birds and butterflies responded quite similarly to the elevational gradient and to the shift between vegetation belts in terms of species turnover rates. While the mechanisms generating these patterns may differ, the resulting areas of peak turnover in species show correspondence among three different taxa (plants, birds and butterflies).

Archaeological Investigation in the Perry Lake Project Area, Northeastern Kansas National Register Evaluation of 17 Sites

DTIC Science & Technology

1989-01-01

Muscotah and Arrington marshes reveal the presence of open vegetation, with some pine, spruce, and birch trees and local stands of alder and willow...1977). Zone 4 pollen frequency curves demonstrate the dynamic nature of the prairie-forest ecotone. In zone 4a, grasses and deciduous trees are both...ecotone. Trees disappeared from the uplands and low values of some types of arboreal pollen suggest that the Delaware River floodplain "dried out over

Ecohydrological implications of aeolian sediment trapping by sparse vegetation in drylands

USGS Publications Warehouse

Gonzales, Howell B.; Ravi, Sujith; Li, Junran; Sankey, Joel B.

2018-01-01

Aeolian processes are important drivers of ecosystem dynamics in drylands, and important feedbacks exist among aeolian – hydrological processes and vegetation. The trapping of wind-borne sediments by vegetation may result in changes in soil properties beneath the vegetation, which, in turn, can alter hydrological and biogeochemical processes. Despite the relevance of aeolian transport to ecosystem dynamics, the interactions between aeolian transport and vegetation in shaping dryland landscapes where sediment distribution is altered by relatively rapid changes in vegetation composition such as shrub encroachment, is not well understood. Here, we used a computational fluid dynamics (CFD) modeling framework to investigate the sediment trapping efficiencies of vegetation canopies commonly found in a shrub-grass ecotone in the Chihuahuan Desert (New Mexico, USA) and related the results to spatial heterogeneity in soil texture and infiltration measured in the field. A CFD open-source software package was used to simulate aeolian sediment movement through three-dimensional architectural depictions of Creosote shrub (Larrea tridentata) and Black Grama grass (Bouteloua eriopoda) vegetation types. The vegetation structures were created using a computer-aided design software (Blender), with inherent canopy porosities, which were derived using LIDAR (Light Detection and Ranging) measurements of plant canopies. Results show that considerable heterogeneity in infiltration and soil grain size distribution exist between the microsites, with higher infiltration and coarser soil texture under shrubs. Numerical simulations also indicate that the differential trapping of canopies might contribute to the observed heterogeneity in soil texture. In the early stages of encroachment, the shrub canopies, by trapping coarser particles more efficiently, might maintain higher infiltration rates leading to faster development of the microsites (among other factors) with enhanced ecological productivity, which might provide positive feedbacks to shrub encroachment.

Classification of Maize and Weeds by Bayesian Networks

NASA Astrophysics Data System (ADS)

Chapron, Michel; Oprea, Alina; Sultana, Bogdan; Assemat, Louis

2007-11-01

Precision Agriculture is concerned with all sorts of within-field variability, spatially and temporally, that reduces the efficacy of agronomic practices applied in a uniform way all over the field. Because of these sources of heterogeneity, uniform management actions strongly reduce the efficiency of the resource input to the crop (i.e. fertilization, water) or for the agrochemicals use for pest control (i.e. herbicide). Moreover, this low efficacy means high environmental cost (pollution) and reduced economic return for the farmer. Weed plants are one of these sources of variability for the crop, as they occur in patches in the field. Detecting the location, size and internal density of these patches, along with identification of main weed species involved, open the way to a site-specific weed control strategy, where only patches of weeds would receive the appropriate herbicide (type and dose). Herein, an automatic recognition method of vegetal species is described. First, the pixels of soil and vegetation are classified in two classes, then the vegetation part of the input image is segmented from the distance image by using the watershed method and finally the leaves of the vegetation are partitioned in two parts maize and weeds thanks to the two Bayesian networks.

Assessing Hurricane Katrina Vegetation Damage at Stennis Space Center using IKONOS Image Classification Techniques

NASA Technical Reports Server (NTRS)

Spruce, Joseph P.; Ross, Kenton W.; Graham, William D.

2006-01-01

Hurricane Katrina inflicted widespread damage to vegetation in southwestern coastal Mississippi upon landfall on August 29, 2005. Storm damage to surface vegetation types at the NASA John C. Stennis Space Center (SSC) was mapped and quantified using IKONOS data originally acquired on September 2, 2005, and later obtained via a Department of Defense ClearView contract. NASA SSC management required an assessment of the hurricane s impact to the 125,000-acre buffer zone used to mitigate rocket engine testing noise and vibration impacts and to manage forestry and fire risk. This study employed ERDAS IMAGINE software to apply traditional classification techniques to the IKONOS data. Spectral signatures were collected from multiple ISODATA classifications of subset areas across the entire region and then appended to a master file representative of major targeted cover type conditions. The master file was subsequently used with the IKONOS data and with a maximum likelihood algorithm to produce a supervised classification later refined using GIS-based editing. The final results enabled mapped, quantitative areal estimates of hurricane-induced damage according to general surface cover type. The IKONOS classification accuracy was assessed using higher resolution aerial imagery and field survey data. In-situ data and GIS analysis indicate that the results compare well to FEMA maps of flooding extent. The IKONOS classification also mapped open areas with woody storm debris. The detection of such storm damage categories is potentially useful for government officials responsible for hurricane disaster mitigation.

Patterns of in-soil methane production and atmospheric emission among different land covers of a Lake Erie estuarine wetland

NASA Astrophysics Data System (ADS)

Rey Sanchez, C.; Morin, T. H.; Stefanik, K. C.; Angle, J.; Wrighton, K. C.; Bohrer, G.

2017-12-01

Wetland soils store a great amount of carbon, but also accumulate and emit methane (CH4), a powerful greenhouse gas. To better understand the vertical and horizontal spatial variability of CH4 emissions, we monitored production and fluxes of CH4 in Old Woman Creek, an estuarine wetland of Lake Erie, Ohio, during the growing seasons of 2015 and 2016. Our combined observation methods targeted three different scales: 1) the eddy covariance technique provided continuous high frequency observations integrated over a large spatial footprint; 2) monthly chamber measurements provided sparse point measurements of fluxes in four distinct land-cover types in the wetland: open water, emergent vegetation (Typha spp.), floating vegetation (Nelumbo spp.) and mud flats; and 3) in-situ porewater dialysis samplers, "peepers", provided vertical CH4 concentration data in the soil at the same locations and temporal time steps as the chambers. In addition, we studied gene transcripts to quantify methanogenesis activity along the vertical soil profile. Using integrated chamber and EC measurements, we found an average surface emission rate from Typha, the most abundant vegetated land cover, of 219.4 g CH4-C m-2 y-1, which was much higher than rates reported in similar emergent vegetation types in other wetlands. There was large spatial variation of flux rates, with mud flats having the highest rates of CH4 emission, followed by Nelumbo and Typha patches, and with open water having the lowest emissions. Within the soil column, we applied a numerical model to convert soil methane concentrations to emissions rates. We found that, contrary to current ideas of methane production, most methane was being produced in the well-oxygenated surface soils, probably in anoxic microsites within the oxic layer. Our metatranscriptomic data supported these findings, clearly showing nine times greater methanogenic activity in oxic surface soils relative to deeper anoxic soils. Combined, our results provide important insights for the representation of processes of methane production and consumption in models, which can largely affect the estimates of methane emission from wetlands.

Vegetation Analysis and Land Use Land Cover Classification of Forest in Uttara Kannada District India Using Remote Sensign and GIS Techniques

NASA Astrophysics Data System (ADS)

Koppad, A. G.; Janagoudar, B. S.

2017-10-01

The study was conducted in Uttara Kannada districts during the year 2012-2014. The study area lies between 13.92° N to 15.52° N latitude and 74.08° E to 75.09° E longitude with an area of 10,215 km2. The Indian satellite IRS P6 LISS-III imageries were used to classify the land use land cover classes with ground truth data collected with GPS through supervised classification in ERDAS software. The land use and land cover classes identified were dense forest, horticulture plantation, sparse forest, forest plantation, open land and agriculture land. The dense forest covered an area of 63.32 % (6468.70 sq km) followed by agriculture 12.88 % (1315.31 sq. km), sparse forest 10.59 % (1081.37 sq. km), open land 6.09 % (622.37 sq. km), horticulture plantation and least was forest plantation (1.07 %). Settlement, stony land and water body together cover about 4.26 percent of the area. The study indicated that the aspect and altitude influenced the forest types and vegetation pattern. The NDVI map was prepared which indicated that healthy vegetation is represented by high NDVI values between 0.1 and 1. The non- vegetated features such as water bodies, settlement, and stony land indicated less than 0.1 values. The decrease in forest area in some places was due to anthropogenic activities. The thematic map of land use land cover classes was prepared using Arc GIS Software.

Movement patterns of rural and suburban white-tailed deer in Massachusetts

USGS Publications Warehouse

Gaughan, C.R.; DeStefano, S.

2005-01-01

We used satellite land cover data and the program FRAGSTATS toquantify land cover types and calculate the amount of forest edge available in suburban and rural regions of northeastern and northwestern Massachusetts. Cover categories included forest cover, open canopy vegetation, and non-deer habitat. We calculated all edge segments where forest cover abutted open canopy cover. Our open canopy vegetation category was calculated both with and without low intensity suburban development. We then compared these findings to movement data from 53 (13 males, 40 females) adult radio-marked white-tailed deerOdocoileus virginianusmonitored biweekly and diurnally from January 2001 to January 2003. The range of movements of suburban deer in eastern Massachusetts showed no difference to that of suburban deer in western Massachusetts (P = 0.7). However, the ranges for suburban deer in both eastern and western Massachusetts were 10 times less than those of deer in rural western Massachusetts (P = 0.001).Our findings suggest that landscape configuration, as described by the amount and distribution of edge due to suburban development, which is related to the amount and distribution of resources such as food and cover, affects migratory behavior of white-tailed deer, allowsdeer to have smaller ranges, and contributes to high deer densities.Inclusion of suburban edge in habitat models will increase our understanding of deer-habitat relationships for management of deer in urbanizing environments. ?? 2005 Springer Science + Business Media, Inc.

Floral and nesting resources, habitat structure, and fire influence bee distribution across an open-forest gradient

USGS Publications Warehouse

Grundel, R.; Jean, R.P.; Frohnapple, K.J.; Glowacki, G.A.; Scott, P.E.; Pavlovic, N.B.

2010-01-01

Given bees' central effect on vegetation communities, it is important to understand how and why bee distributions vary across ecological gradients. We examined how plant community composition, plant diversity, nesting suitability, canopy cover, land use, and fire history affected bee distribution across an open-forest gradient in northwest Indiana, USA, a gradient similar to the historic Midwest United States landscape mosaic. When considered with the other predictors, plant community composition was not a significant predictor of bee community composition. Bee abundance was negatively related to canopy cover and positively to recent fire frequency, bee richness was positively related to plant richness and abundance of potential nesting resources, and bee community composition was significantly related to plant richness, soil characteristics potentially related to nesting suitability, and canopy cover. Thus, bee abundance was predicted by a different set of environmental characteristics than was bee species richness, and bee community composition was predicted, in large part, by a combination of the significant predictors of bee abundance and richness. Differences in bee community composition along the woody vegetation gradient were correlated with relative abundance of oligolectic, or diet specialist, bees. Because oligoleges were rarer than diet generalists and were associated with open habitats, their populations may be especially affected by degradation of open habitats. More habitat-specialist bees were documented for open and forest/scrub habitats than for savanna/woodland habitats, consistent with bees responding to habitats of intermediate woody vegetation density, such as savannas, as ecotones rather than as distinct habitat types. Similarity of bee community composition, similarity of bee abundance, and similarity of bee richness between sites were not significantly related to proximity of sites to each other. Nestedness analysis indicated that species composition in species-poor sites was not merely a subset of species composition at richer sites. The lack of significant proximity or nestedness effects suggests that factors at a small spatial scale strongly influence bees' use of sites. The findings indicate that patterns of plant diversity, nesting resource availability, recent fire, and habitat shading, present at the scale of a few hundred meters, are key determinants of bee community patterns in the mosaic open-savanna-forest landscape. ?? 2010 by the Ecological Society of America.

Under-canopy snow accumulation and ablation measured with airborne scanning LiDAR altimetry and in-situ instrumental measurements, southern Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Kirchner, P. B.; Bales, R. C.; Musselman, K. N.; Molotch, N. P.

2012-12-01

We investigated the influence of canopy on snow accumulation and melt in a mountain forest using paired snow on and snow off scanning LiDAR altimetry, synoptic measurement campaigns and in-situ time series data of snow depth, SWE, and radiation collected from the Kaweah River watershed, Sierra Nevada, California. Our analysis of forest cover classified by dominant species and 1 m2 grided mean under canopy snow accumulation calculated from airborne scanning LiDAR, demonstrate distinct relationships between forest class and under-canopy snow depth. The five forest types were selected from carefully prepared 1 m vegetation classifications and named for their dominant tree species, Giant Sequoia, Jeffrey Pine, White Fir, Red Fir, Sierra Lodgepole, Western White Pine, and Foxtail Pine. Sufficient LiDAR returns for calculating mean snow depth per m2 were available for 31 - 44% of the canopy covered area and demonstrate a reduction in snow depth of 12 - 24% from adjacent open areas. The coefficient of variation in snow depth under canopies ranged from 0.2 - 0.42 and generally decreased as elevation increased. Our analysis of snow density snows no statistical significance between snow under canopies and in the open at higher elevations with a weak significance for snow under canopies at lower elevations. Incident radiation measurements made at 15 minute intervals under forest canopies show an input of up to 150 w/m2 of thermal radiation from vegetation to the snow surface on forest plots. Snow accumulated on the mid to high elevation forested slopes of the Sierra Nevada represents the majority of winter snow storage. However snow estimates in forested environments demonstrate a high level of uncertainty due to the limited number of in-situ observations and the inability of most remote sensing platforms to retrieve reflectance under dense vegetation. Snow under forest canopies is strongly mediated by forest cover and decoupled from the processes that dictate accumulation and ablation of snow in open locations, where almost all precipitation and meteorlogic measurements concerning snow are made. Snow accumulation is intercepted by vegetation until it accumulates to a depth equal to or greater than the height of the vegetation, is reduced by the amount of sublimation or evaporation occurring while on the canopy and is redistributed beneath the canopy at a different density or as liquid water. Ablation processes are dictated by the energy environment surrounding vegetation where sensible heat is mediated by shading of short wave radiation.

Experimental trampling of vegetation. I. Relationship between trampling intensity and vegetation response

Treesearch

David N. Cole

1995-01-01

1. Experimental trampling was conducted in 18 vegetation types in five separate mountain regions in the United States. Each type was trampled 0-500 times. Response to trampling was assessed by determining vegetation cover 2 weeks after trampling and 1 year after trampling.2. Response varied significantly with trampling intensity and vegetation type. Trampling...

The gene for a lectin-like protein is transcriptionally activated during sexual development, but is not essential for fruiting body formation in the filamentous fungus Sordaria macrospora.

PubMed

Nowrousian, Minou; Cebula, Patricia

2005-11-03

The filamentous fungus Sordaria macrospora forms complex three-dimensional fruiting bodies called perithecia that protect the developing ascospores and ensure their proper discharge. In previous microarray analyses, several genes have been identified that are downregulated in sterile mutants compared to the wild type. Among these genes was tap1 (transcript associated with perithecial development), a gene encoding a putative lectin homolog. Analysis of tap1 transcript levels in the wild type under conditions allowing only vegetative growth compared to conditions that lead to fruiting body development showed that tap1 is not only downregulated in developmental mutants but is also upregulated in the wild type during fruiting body development. We have cloned and sequenced a 3.2 kb fragment of genomic DNA containing the tap1 open reading frame and adjoining sequences. The genomic region comprising tap1 is syntenic to its homologous region in the closely related filamentous fungus Neurospora crassa. To determine whether tap1 is involved in fruiting body development in S. macrospora, a knockout construct was generated in which the tap1 open reading frame was replaced by the hygromycin B resistance gene hph under the control of fungal regulatory regions. Transformation of the S. macrospora wild type with this construct resulted in a tap1 deletion strain where tap1 had been replaced by the hph cassette. The knockout strain displayed no phenotypic differences under conditions of vegetative growth and sexual development when compared to the wild type. Double mutants carrying the Deltatap1 allele in several developmental mutant backgrounds were phenotypically similar to the corresponding developmental mutant strains. The tap1 transcript is strongly upregulated during sexual development in S. macrospora; however, analysis of a tap1 knockout strain shows that tap1 is not essential for fruiting body formation in S. macrospora.

The gene for a lectin-like protein is transcriptionally activated during sexual development, but is not essential for fruiting body formation in the filamentous fungus Sordaria macrospora

PubMed Central

Nowrousian, Minou; Cebula, Patricia

2005-01-01

Background The filamentous fungus Sordaria macrospora forms complex three-dimensional fruiting bodies called perithecia that protect the developing ascospores and ensure their proper discharge. In previous microarray analyses, several genes have been identified that are downregulated in sterile mutants compared to the wild type. Among these genes was tap1 (transcript associated with perithecial development), a gene encoding a putative lectin homolog. Results Analysis of tap1 transcript levels in the wild type under conditions allowing only vegetative growth compared to conditions that lead to fruiting body development showed that tap1 is not only downregulated in developmental mutants but is also upregulated in the wild type during fruiting body development. We have cloned and sequenced a 3.2 kb fragment of genomic DNA containing the tap1 open reading frame and adjoining sequences. The genomic region comprising tap1 is syntenic to its homologous region in the closely related filamentous fungus Neurospora crassa. To determine whether tap1 is involved in fruiting body development in S. macrospora, a knockout construct was generated in which the tap1 open reading frame was replaced by the hygromycin B resistance gene hph under the control of fungal regulatory regions. Transformation of the S. macrospora wild type with this construct resulted in a tap1 deletion strain where tap1 had been replaced by the hph cassette. The knockout strain displayed no phenotypic differences under conditions of vegetative growth and sexual development when compared to the wild type. Double mutants carrying the Δtap1 allele in several developmental mutant backgrounds were phenotypically similar to the corresponding developmental mutant strains. Conclusion The tap1 transcript is strongly upregulated during sexual development in S. macrospora; however, analysis of a tap1 knockout strain shows that tap1 is not essential for fruiting body formation in S. macrospora. PMID:16266439

Differentiating climatic and successional influences on long-term development of a marsh

USGS Publications Warehouse

Singer, Darren K.; Jackson, Stephen T.; Madsen, Barbara J.; Wilcox, Douglas A.

1996-01-01

Comparison of long—term records of local wetland vegetation dynamics with regional, climate—forced terrestrial vegetation changes can be used to differentiate the rates and effects of autogenic successional processes and allogenic environmental change on wetland vegetation dynamics. We studied Holocene plant macrofossil and pollen sequences from Portage Marsh, a shallow, 18—ha marsh in northeastern Indiana. Between 10 000 and 5700 yr BP the basin was occupied by a shallow, open lake, while upland vegetation consisted of mesic forests of Pinus, Quercus, Ulmus, and Carya. At 5700 yr BP the open lake was replaced rapidly by a shallow marsh, while simultaneously Quercus savanna developed on the surrounding uplands. The marsh was characterized by periodic drawdowns, and the uplands by periodic fires. Species composition of the marsh underwent further changes between 3000 and 2000 yr BP. Upland pollen spectra at Portage Marsh and other sites in the region shifted towards more mesic vegetation during that period. The consistency and temporal correspondence between the changes in upland vegetation and marsh vegetation indicate that the major vegetational changes in the marsh during the Holocene resulted from hydrologic changes forced by regional climate change. Progressive shallowing of the basin by autogenic accumulation of organic sediment constrained vegetational responses to climate change but did not serve as the direct mechanism of change.

An approach for detecting five typical vegetation types on the Chinese Loess Plateau using Landsat TM data.

PubMed

Wang, Zhi-Jie; Jiao, Ju-Ying; Lei, Bo; Su, Yuan

2015-09-01

Remote sensing can provide large-scale spatial data for the detection of vegetation types. In this study, two shortwave infrared spectral bands (TM5 and TM7) and one visible spectral band (TM3) of Landsat 5 TM data were used to detect five typical vegetation types (communities dominated by Bothriochloa ischaemum, Artemisia gmelinii, Hippophae rhamnoides, Robinia pseudoacacia, and Quercus liaotungensis) using 270 field survey data in the Yanhe watershed on the Loess Plateau. The relationships between 200 field data points and their corresponding radiance reflectance were analyzed, and the equation termed the vegetation type index (VTI) was generated. The VTI values of five vegetation types were calculated, and the accuracy was tested using the remaining 70 field data points. The applicability of VTI was also tested by the distribution of vegetation type of two small watersheds in the Yanhe watershed and field sample data collected from other regions (Ziwuling Region, Huangling County, and Luochuan County) on the Loess Plateau. The results showed that the VTI can effectively detect the five vegetation types with an average accuracy exceeding 80 % and a representativeness above 85 %. As a new approach for monitoring vegetation types using remote sensing at a larger regional scale, VTI can play an important role in the assessment of vegetation restoration and in the investigation of the spatial distribution and community diversity of vegetation on the Loess Plateau.

What role do beds of submerged macrophytes play in structuring estuarine fish assemblages? Lessons from a warm-temperate South African estuary

NASA Astrophysics Data System (ADS)

Sheppard, Jill N.; James, Nicola C.; Whitfield, Alan K.; Cowley, Paul D.

2011-11-01

Habitat variability is one of the factors influencing species richness within estuarine systems, and a loss of habitat can result in a restructuring of the estuarine ichthyofaunal assemblage, particularly if these conditions persist over long time periods. The potential effects of the loss of extensive submerged macrophyte beds ( Ruppia cirrhosa and Potamogeton pectinatus) on an estuarine fish assemblage were investigated through an analysis of a long-term seine net catch dataset from the temporarily open/closed East Kleinemonde Estuary, South Africa. Catch data for a 12-year period, encompassing six years of macrophyte presence and six years of macrophyte senescence, indicated that the loss of this habitat did not influence species richness but changes in the relative abundance of certain species were evident. A shift in dominance from vegetation-associated species to those associated with sandy environments ( e.g. members of the family Mugilidae) was observed. However, species wholly dependent on macrophytes such as the critically endangered estuarine pipefish Syngnathus watermeyeri were only recorded during years when macrophyte beds were present, while vegetation-associated species such as the sparid Rhabdosargus holubi persisted at lower levels of relative abundance. The reduced abundance of all vegetation-associated fish species during years of macrophyte senescence was probably reflective of declining food resources resulting from the loss of macrophyte beds and/or increased vulnerability to predation. Submerged beds of aquatic plants are therefore important habitats within temporarily open/closed estuaries, South Africa's dominant estuary type.

Predicting Changes in Arctic Tundra Vegetation: Towards an Understanding of Plant Trait Uncertainty

NASA Astrophysics Data System (ADS)

Euskirchen, E. S.; Serbin, S.; Carman, T.; Iversen, C. M.; Salmon, V.; Helene, G.; McGuire, A. D.

2017-12-01

Arctic tundra plant communities are currently undergoing unprecedented changes in both composition and distribution under a warming climate. Predicting how these dynamics may play out in the future is important since these vegetation shifts impact both biogeochemical and biogeophysical processes. More precise estimates of these future vegetation shifts is a key challenge due to both a scarcity of data with which to parameterize vegetation models, particularly in the Arctic, as well as a limited understanding of the importance of each of the model parameters and how they may vary over space and time. Here, we incorporate newly available field data from arctic Alaska into a dynamic vegetation model specifically developed to take into account a particularly wide array of plant species as well as the permafrost soils of the arctic tundra (the Terrestrial Ecosystem Model with Dynamic Vegetation and Dynamic Organic Soil, Terrestrial Ecosystem Model; DVM-DOS-TEM). We integrate the model within the Predicative Ecosystem Analyzer (PEcAn), an open-source integrated ecological bioinformatics toolbox that facilitates the flows of information into and out of process models and model-data integration. We use PEcAn to evaluate the plant functional traits that contribute most to model variability based on a sensitivity analysis. We perform this analysis for the dominant types of tundra in arctic Alaska, including heath, shrub, tussock and wet sedge tundra. The results from this analysis will help inform future data collection in arctic tundra and reduce model uncertainty, thereby improving our ability to simulate Arctic vegetation structure and function in response to global change.

Diminished mercury emission from waters with duckweed cover

NASA Astrophysics Data System (ADS)

Wollenberg, Jennifer L.; Peters, Stephen C.

2009-06-01

Duckweeds (Lemnaceae) are a widely distributed type of floating vegetation in freshwater systems. Under suitable conditions, duckweeds form a dense vegetative mat on the water surface, which reduces light penetration into the water column and limits gas exchange at the water-air interface by decreasing the area of open water surface. Experiments were conducted to determine whether duckweed decreases mercury emission by limiting gas diffusion across the water-air interface and attenuating light, or, conversely, enhances emission via transpiration of mercury vapor. Microcosm flux chamber experiments indicate that duckweed decreases mercury emission from the water surface compared to open water controls. Fluxes under duckweed were 17-67% lower than in controls, with lower fluxes occurring at higher percent cover. The decrease in mercury emission suggests that duckweed may limit emission through one of several mechanisms, including limited gas transport across the air-water interface, decreased photoreactions due to light attenuation, and plant-mercury interactions. The results of this experiment were applied to a model lake system to illustrate the magnitude of potential effects on mercury cycling. The mercury retained in the lake as a result of hindered emission may increase bioaccumulation potential in lakes with duckweed cover.

Boreal coniferous forest density leads to significant variations in soil physical and geochemical properties

NASA Astrophysics Data System (ADS)

Bastianelli, Carole; Ali, Adam A.; Beguin, Julien; Bergeron, Yves; Grondin, Pierre; Hély, Christelle; Paré, David

2017-07-01

At the northernmost extent of the managed forest in Quebec, Canada, the boreal forest is currently undergoing an ecological transition between two forest ecosystems. Open lichen woodlands (LW) are spreading southward at the expense of more productive closed-canopy black spruce-moss forests (MF). The objective of this study was to investigate whether soil properties could distinguish MF from LW in the transition zone where both ecosystem types coexist. This study brings out clear evidence that differences in vegetation cover can lead to significant variations in soil physical and geochemical properties.Here, we showed that soil carbon, exchangeable cations, and iron and aluminium crystallinity vary between boreal closed-canopy forests and open lichen woodlands, likely attributed to variations in soil microclimatic conditions. All the soils studied were typical podzolic soil profiles evolved from glacial till deposits that shared a similar texture of the C layer. However, soil humus and the B layer varied in thickness and chemistry between the two forest ecosystems at the pedon scale. Multivariate analyses of variance were used to evaluate how soil properties could help distinguish the two types at the site scale. MF humus (FH horizons horizons composing the O layer) showed significantly higher concentrations of organic carbon and nitrogen and of the main exchangeable base cations (Ca, Mg) than LW soils. The B horizon of LW sites held higher concentrations of total Al and Fe oxides and particularly greater concentrations of inorganic amorphous Fe oxides than MF mineral soils, while showing a thinner B layer. Overall, our results show that MF store three times more organic carbon in their soils (B+FH horizons, roots apart) than LW. We suggest that variations in soil properties between MF and LW are linked to a cascade of events involving the impacts of natural disturbances such as wildfires on forest regeneration that determines the vegetation structure (stand density) and composition (ground cover type) and their subsequent consequences on soil environmental parameters (moisture, radiation rate, redox conditions, etc.). Our data underline significant differences in soil biogeochemistry under different forest ecosystems and reveal the importance of interactions in the soil-vegetation-climate system for the determination of soil composition.

Late Pliocene vegetation and orbital-scale climate changes from the western Mediterranean area

NASA Astrophysics Data System (ADS)

Jiménez-Moreno, Gonzalo; Burjachs, Francesc; Expósito, Isabel; Oms, Oriol; Carrancho, Ángel; Villalaín, Juan José; Agustí, Jordi; Campeny, Gerard; Gómez de Soler, Bruno; van der Made, Jan

2013-09-01

The Late Pliocene is a very interesting period as climate deteriorated from a warm optimum at ca. 3.3-3.0 Ma to a progressive climate cooling. Simultaneously, the Mediterranean area witnessed the establishment of the Mediterranean-type seasonal precipitation rhythm (summer drought). These important climate changes produced significant vegetation changes, such as the extinction of several thermophilous and hygrophilous plant taxa from the European latitudes. Besides these long-term trends, climate was also characterized by cyclical variability (i.e., orbital changes) that forced vegetation changes (forested vs. open vegetation). In the Mediterranean area, cyclical changes in the vegetation were mostly forced by precession. In this study we analyzed pollen from a Late Pliocene maar lake core from NE Spain. An increase in aridity is observed as well as cyclic variations throughout the studied sequence. Cyclicity was mostly forced by precession but also by obliquity and eccentricity. Precipitation seems to be the main factor controlling these cycles. These data allowed estimating a sedimentary rate of ca. 0.19 mm/yr and the time duration covered by the studied core, close to 200 ka. The combination of biostratigraphy, palaeomagnetism and cyclostratigraphy allowed for a very precise dating of the sediments between ca. 3.3 and 3.1 Ma. Climate and paleobiogeographical implications are discussed within the context of the Late Pliocene Northern Hemisphere glacial intensification.

Vegetative Incompatibility and the Mating-Type Locus in the Cellular Slime Mold DICTYOSTELIUM DISCOIDEUM

PubMed Central

Robson, Gillian E.; Williams, Keith L.

1979-01-01

The genetic basis of vegetative incompatibility in the cellular slime mold, Dictyostelium discoideum, is elucidated. Vegetatively compatible haploid strains from parasexual diploids at a frequency of between 10-6 and 10-5, whereas "escaped" diploids are formed between vegetatively incompatible strains at a frequency of ∼10-8. There is probably only a single vegetative incompatibility site, which appears to be located at, or closely linked to, the mating-type locus. The nature of the vegetative incompatibility is deduced from parasexual diploid formation between wild isolates and tester strains of each mating type, examination of the frequency of formation of "escaped" diploids formed between vegetatively incompatible strains, and examination of the mating type and vegetative incompatibility of haploid segregants obtained from "escaped" diploids. PMID:17248984

The spectral response of Buxus sempervirens to different types of environmental stress - A laboratory experiment

NASA Astrophysics Data System (ADS)

de Jong, Steven M.; Addink, Elisabeth A.; Hoogenboom, Priscilla; Nijland, Wiebe

2012-11-01

The European Mediterranean regions are expected to encounter drier summer conditions and warmer temperatures for the winter of +2 °C and of +5 °C for the summer in the next six decennia. As a result the natural vegetation will face harsher conditions due to lower water availability, longer summer droughts and higher temperatures resulting in plant stress conditions. To monitor vegetation conditions like stress and leaf area index dynamics in our study area in Mediterranean France we use earth observation techniques like imaging spectroscopy. To assist image analysis interpretation we carried out a laboratory experiment to investigate the spectral and visible response of Buxus sempervirens, a common Mediterranean species, to five different types of stress: drought, drought-and-heat, light deprivation, total saturation and chlorine poisoning. For 52 days plants were subjected to stress. We collected data on the visible and spectral signs, and calculated thirteen vegetation indices. The plant's response time to different stress types varied from 10 to 32 days. Spectroscopic techniques revealed plant stress up to 15 days earlier than visual inspection. Visible signs of stress of the plants included curling and shrinking of the leaves, de-colouring of the leaves, leaves becoming breakable, opening up of the plant's canopy and sagging of the branches. Spectral signs of stress occurred first in the water absorption bands at 1450 and 1940 nm, followed by reduced absorption in the visible wavelengths, and next by reduced reflectance in near infrared. Light deprivation did not result in any stress signs, while drought, drought and heat and chlorine poisoning resulted in significant stress. The spectral response did not show differences for different stress types. Analysis of the vegetation indices identified the Carter-2 (R695/R760), the Red-Green Index (R690/R550) and the Vogelman-2 (R734 - R747)/(R715 + R726) as the best performing ones to identify stress. The lab experiment shows that spectroscopic techniques are useful to detect stress status of plants and in an earlier stage than visible signs of stress become apparent, but that spectroscopy does not reveal the type of plant stress.

Assessment of Robinia pseudoacacia cultivations as a restoration strategy for reclaimed mine spoil heaps.

PubMed

Vlachodimos, Kostas; Papatheodorou, Efimia M; Diamantopoulos, John; Monokrousos, Nikolaos

2013-08-01

Reforestation with black locust (Robinia pseudoacacia) is considered a successful technique that is often used for the reclamation of open-cast mine areas. An alternative reclamation technique could be the natural regeneration of vegetation with spontaneous grass species. In this study, we compared the concentrations of chemical and biochemical variables in soil samples taken under black locust canopy to those from sites covered by spontaneous grass vegetation (control samples) in a time sequence of spoil deposition (0-10 years), in order to assess which of the two reclamation techniques yields higher soil quality. Soil quality refers here to the ability of soils to function ecologically. This has a special interest since the main question for the restored soils is their capacity to perform a range of ecological functions under stress or disturbance. Furthermore, we aimed at identifying the effect of vegetation type on soil ecological succession. The effect of vegetation type on primary succession becomes apparent after 2 years of reclamation. R. pseudoacacia as a nitrogen-fixing plant enriched soil with organic and inorganic nitrogen and organic matter to a greater extent than the natural grasses. It also increased the amount of soil microbial biomass and the activity of alkaline phosphatase. However, the fact that black locust failed to enhance dehydrogenase activity and actually decreased the activity of urease, activities that represent specialized niche functions and therefore, are more vulnerable to stress or disturbance, suggests that the development of an indigenous grass community in combination with organic supplements might often be more appropriate for the reclamation of similar kinds of mine areas.

Spatio-temporal development of vegetation die-off in a submerging coastal marsh

USGS Publications Warehouse

Schepers, Lennert; Kirwan, Matthew; Guntenspergen, Glenn R.; Temmerman, Stijn

2017-01-01

In several places around the world, coastal marsh vegetation is converting to open water through the formation of pools. This is concerning, as vegetation die-off is expected to reduce the marshes' capacity to adapt to sea level rise by vegetation-induced sediment accretion. Quantitative analyses of the spatial and temporal development of marsh vegetation die-off are scarce, although these are needed to understand the bio-geomorphic feedback effects of vegetation die-off on flow, erosion, and sedimentation. In this study, we quantified the spatial and temporal development of marsh vegetation die-off with aerial images from 1938 to 2010 in a submerging coastal marsh along the Blackwater River (Maryland, U.S.A). Our results indicate that die-off begins with conversion of marsh vegetation into bare open water pools that are relatively far (> 75 m) from tidal channels. As vegetation die-off continues, pools expand, and new pools emerge at shorter and shorter distances from channels. Consequently larger pools are found at larger distances from the channels. Our results suggest that the size of the pools and possibly the connection of pools with the tidal channel system have important bio-geomorphic implications and aggravate marsh deterioration. Moreover, we found that the temporal development of vegetation die-off in moderately degraded marshes is similar as the spatial die-off development along a present-day gradient, which indicates that the contemporary die-off gradient might be considered a chronosequence that offers a unique opportunity to study vegetation die-off processes.

Mapping wetlands on beaver flowages with 35-mm photography

USGS Publications Warehouse

Kirby, R.E.

1976-01-01

Beaver flowages and associated wetlands on the Chippewa National Forest, north-central Minnesota, were photographed from the ground and from the open side window of a small high-wing monoplane. The 35-mm High Speed Ektachrome transparencies obtained were used to map the cover-type associations visible on the aerial photographs. Nearly vertical aerial photos were rectified by projecting the slides onto a base map consisting ofcontrol points located by plane-table survey. Maps were prepared by tracing the recognizable stands of vegetation in the rectified projection at the desired map scale. Final map scales ranging from 1:260 to 1:571 permitted identification and mapping of 26 cover-type associations on 10 study flowages in 1971. This cover-mapping technique was economical and substituted for detailed ground surveys. Comparative data from 10 flowages were collected serially throughout the entire open-water season. Although developed for analysis of waterfowl habitat, the technique has application to other areas of wildlife management and ecological investigation.

The consequences of trampling disturbance in two vegetation types at the Wyoming Nature Conservancy's Sweetwater River project area

Treesearch

Christopher A. Monz; Tami Pokorny; Jerry Freilich; Sharon Kehoe; Dayna Ayers-Baumeister

2000-01-01

The consequences of human trampling disturbance on two codominant vegetation types at the Wyoming Nature Conservancy’s Sweetwater Preserve were examined. Small trampling lanes (1.5m x 0.5m) were established in both vegetation types and trampling treatments ranging from 0 to 800 passes were applied. Artemisia (Sagebrush) vegetation type was more...

Predicting species interactions from edge responses: mongoose predation on hawksbill sea turtle nests in fragmented beach habitat.

PubMed

Leighton, Patrick A; Horrocks, Julia A; Krueger, Barry H; Beggs, Jennifer A; Kramer, Donald L

2008-11-07

Because species respond differently to habitat boundaries and spatial overlap affects encounter rates, edge responses should be strong determinants of spatial patterns of species interactions. In the Caribbean, mongooses (Herpestes javanicus) prey on hawksbill sea turtle (Eretmochelys imbricata) eggs. Turtles nest in both open sand and vegetation patches, with a peak in nest abundance near the boundary between the two microhabitats; mongooses rarely leave vegetation. Using both artificial nests and hawksbill nesting data, we examined how the edge responses of these species predict the spatial patterns of nest mortality. Predation risk was strongly related to mongoose abundance but was not affected by nest density or habitat type. The product of predator and prey edge response functions accurately described the observed pattern of total prey mortality. Hawksbill preference for vegetation edge becomes an ecological trap in the presence of mongooses. This is the first study to predict patterns of predation directly from continuous edge response functions of interacting species, establishing a link between models of edge response and species interactions.

Predicting species interactions from edge responses: mongoose predation on hawksbill sea turtle nests in fragmented beach habitat

PubMed Central

Leighton, Patrick A; Horrocks, Julia A; Krueger, Barry H; Beggs, Jennifer A; Kramer, Donald L

2008-01-01

Because species respond differently to habitat boundaries and spatial overlap affects encounter rates, edge responses should be strong determinants of spatial patterns of species interactions. In the Caribbean, mongooses (Herpestes javanicus) prey on hawksbill sea turtle (Eretmochelys imbricata) eggs. Turtles nest in both open sand and vegetation patches, with a peak in nest abundance near the boundary between the two microhabitats; mongooses rarely leave vegetation. Using both artificial nests and hawksbill nesting data, we examined how the edge responses of these species predict the spatial patterns of nest mortality. Predation risk was strongly related to mongoose abundance but was not affected by nest density or habitat type. The product of predator and prey edge response functions accurately described the observed pattern of total prey mortality. Hawksbill preference for vegetation edge becomes an ecological trap in the presence of mongooses. This is the first study to predict patterns of predation directly from continuous edge response functions of interacting species, establishing a link between models of edge response and species interactions. PMID:18647718

Do ecohydrology and community dynamics feed back to banded-ecosystem structure and productivity?

NASA Astrophysics Data System (ADS)

Callegaro, Chiara; Ursino, Nadia

2016-04-01

Mixed communities including grass, shrubs and trees are often reported to populate self-organized vegetation patterns. Patterns of survey data suggest that species diversity and complementarity strengthen the dynamics of banded environments. Resource scarcity and local facilitation trigger self organization, whereas coexistence of multiple species in vegetated self-organizing patches, implying competition for water and nutrients and favorable reproduction sites, is made possible by differing adaptation strategies. Mixed community spatial self-organization has so far received relatively little attention, compared with local net facilitation of isolated species. We assumed that soil moisture availability is a proxy for the environmental niche of plant species according to Ursino and Callegaro (2016). Our modelling effort was focused on niche differentiation of coexisting species within a tiger bush type ecosystem. By minimal numerical modelling and stability analysis we try to answer a few open scientific questions: Is there an adaptation strategy that increases biodiversity and ecosystem functioning? Does specific adaptation to environmental niches influence the structure of self-organizing vegetation pattern? What specific niche distribution along the environmental gradient gives the highest global productivity?

Humid to arid to subhumid vegetation shift on Pilliga Sandstone, Ulungra Springs, New South Wales

NASA Astrophysics Data System (ADS)

Dodson, J. R.; Wright, R. V. S.

1989-09-01

The Pilliga Sandstone region of the northwest slope of New South Wales has a natural vegetation cover of sclerophyllous relatively closed to open forests with a largely heathy understorey, and a warm, subhumid and continental climate. Pollen analysis of spring-fed deposits gives a vegetation history extending from at least 30,000 yr B.P. to the late Holocene. Tree pollen became scarce after about 25,000 yr B.P. and an assemblage dominated by Chenopodiaceae, Liguliflorae, Tubuliflorae, and probably Poaceae developed. No similar assemblage is known from present pollen rain studies carried out in Australia. However, it clearly represents a treeless open shrub-steppe formation and therefore an arid or semiarid environment. The site thus provides evidence of an eastward late Pleistocene extension of the arid zone in Australia, and is the first full-glacial vegetation record between 20° and 35° latitude in Australia. The present vegetation cover did not become reestablished until the beginning of the Holocene, which raises questions about the form in which Pilliga Sandstone vegetation survived full-glacial conditions.

Vegetable peptones increase production of type I collagen in human fibroblasts by inducing the RSK-CCAAT/enhancer binding protein-β phosphorylation pathway.

PubMed

Jung, Eunsun; Cho, Jae Youl; Park, Deokhoon; Kim, Min Hee; Park, Beomseok; Lee, Sang Yeol; Lee, Jongsung

2015-02-01

Skin aging appears to be principally attributed to a decrease in type I collagen level and the regeneration ability of dermal fibroblasts. We hypothesized that vegetable peptones promote cell proliferation and production of type I collagen in human dermal fibroblasts. Therefore, we investigated the effects of vegetable peptones on cell proliferation and type I collagen production and their possible mechanisms in human dermal fibroblasts. Vegetable peptones significantly promoted cell proliferation in a concentration-dependent manner. In addition, the human luciferase type I collagen α2 promoter and type I procollagen synthesis assays showed that the vegetable peptones induced type I procollagen production by activating the type I collagen α2 promoter. Moreover, the vegetable peptones activated p90 ribosomal s6 kinase, which was mediated by activating the Raf-p44/42 mitogen-activated protein kinase signaling pathway. Furthermore, the vegetable peptone-induced increase in cell proliferation and type I collagen production decreased upon treatment with the ERK inhibitor PD98059. Taken together, these findings suggest that increased proliferation of human dermal fibroblasts and enhanced production of type I collagen by vegetable peptones occur primarily by inducing the p90 ribosomal s6 kinase-CCAAT/enhancer binding protein β phosphorylation pathway, which is mediated by activating Raf-ERK signaling. Copyright © 2015 Elsevier Inc. All rights reserved.

Multiscale sampling of plant diversity: Effects of minimum mapping unit size

USGS Publications Warehouse

Stohlgren, T.J.; Chong, G.W.; Kalkhan, M.A.; Schell, L.D.

1997-01-01

Only a small portion of any landscape can be sampled for vascular plant diversity because of constraints of cost (salaries, travel time between sites, etc.). Often, the investigator decides to reduce the cost of creating a vegetation map by increasing the minimum mapping unit (MMU), and/or by reducing the number of vegetation classes to be considered. Questions arise about what information is sacrificed when map resolution is decreased. We compared plant diversity patterns from vegetation maps made with 100-ha, 50-ha, 2-ha, and 0.02-ha MMUs in a 754-ha study area in Rocky Mountain National Park, Colorado, United States, using four 0.025-ha and 21 0.1-ha multiscale vegetation plots. We developed and tested species-log(area) curves, correcting the curves for within-vegetation type heterogeneity with Jaccard's coefficients. Total species richness in the study area was estimated from vegetation maps at each resolution (MMU), based on the corrected species-area curves, total area of the vegetation type, and species overlap among vegetation types. With the 0.02-ha MMU, six vegetation types were recovered, resulting in an estimated 552 species (95% CI = 520-583 species) in the 754-ha study area (330 plant species were observed in the 25 plots). With the 2-ha MMU, five vegetation types were recognized, resulting in an estimated 473 species for the study area. With the 50-ha MMU, 439 plant species were estimated for the four vegetation types recognized in the study area. With the 100-ha MMU, only three vegetation types were recognized, resulting in an estimated 341 plant species for the study area. Locally rare species and keystone ecosystems (areas of high or unique plant diversity) were missed at the 2-ha, 50-ha, and 100-ha scales. To evaluate the effects of minimum mapping unit size requires: (1) an initial stratification of homogeneous, heterogeneous, and rare habitat types; and (2) an evaluation of within-type and between-type heterogeneity generated by environmental gradients and other factors. We suggest that at least some portions of vegetation maps created at a coarser level of resolution be validated at a higher level of resolution.

Developing digital vegetation for central hardwood forest types: A case study from Leslie County, KY

Treesearch

Bo Song; Wei-lun Tsai; Chiao-ying Chou; Thomas M. Williams; William Conner; Brian J. Williams

2011-01-01

Digital vegetation is the computerized representation, with either virtual images or animations, of vegetation types and conditions based on current measurements or ecological models. Digital vegetation can be useful in evaluating past, present, or future land use; changes in vegetation linked to climate change; or restoration efforts. Digital vegetation can be...

Aeolian Sediment Trapping Efficiencies of Sparse Vegetation and its Ecohydrological Consequences in Drylands

NASA Astrophysics Data System (ADS)

Gonzales, H. B.; Ravi, S.; Li, J. J.; Sankey, J. B.

2016-12-01

Hydrological and aeolian processes control the redistribution of soil and nutrients in arid and semi arid environments thereby contributing to the formation of heterogeneous patchy landscapes with nutrient-rich resource islands surrounded by nutrient depleted bare soil patches. The differential trapping of soil particles by vegetation canopies may result in textural changes beneath the vegetation, which, in turn, can alter the hydrological processes such as infiltration and runoff. We conducted infiltration experiments and soil grain size analysis of several shrub (Larrea tridentate) and grass (Bouteloua eriopoda) microsites and in a heterogeneous landscape in the Chihuahuan desert (New Mexico, USA). Our results indicate heterogeneity in soil texture and infiltration patterns under grass and shrub microsites. We assessed the trapping effectiveness of vegetation canopies using a novel computational fluid dynamics (CFD) approach. An open-source software (OpenFOAM) was used to validate the data gathered from particle size distribution (PSD) analysis of soil within the shrub and grass microsites and their porosities (91% for shrub and 68% for grass) determined using terrestrial LiDAR surveys. Three-dimensional architectures of the shrub and grass were created using an open-source computer-aided design (CAD) software (Blender). The readily available solvers within the OpenFOAM architecture were modified to test the validity and optimize input parameters in assessing trapping efficiencies of sparse vegetation against aeolian sediment flux. The results from the numerical simulations explained the observed textual changes under grass and shrub canopies and highlighted the role of sediment trapping by canopies in structuring patch-scale hydrological processes.

The dietary impact of introducing new retailers of fruits and vegetables into a community: results from a systematic review.

PubMed

Woodruff, Rebecca C; Raskind, Ilana G; Harris, Diane M; Gazmararian, Julie A; Kramer, Michael; Haardörfer, Regine; Kegler, Michelle C

2018-04-01

To investigate the potential dietary impact of the opening of new retailers of healthy foods. Systematic review of the peer-reviewed research literature. References published before November 2015 were retrieved from MEDLINE, EMBASE and Web of Science databases using keyword searches. The outcome of the review was change in fruit and vegetable consumption among adults. Of 3514 references retrieved, ninety-two articles were reviewed in full text, and twenty-three articles representing fifteen studies were included. Studies used post-test only (n 4), repeated cross-sectional (n 4) and repeated measures designs (n 7) to evaluate the dietary impact of supermarket (n 7), farmers' market (n 4), produce stand (n 2) or mobile market (n 2) openings. Evidence of increased fruit and vegetable consumption was most consistent among adults who began shopping at the new retailer. Three of four repeated measures studies found modest, albeit not always statistically significant, increases in fruit and vegetable consumption (range 0·23-0·54 servings/d) at 6-12 months after baseline. Dietary change among residents of the broader community where the new retailer opened was less consistent. The methodological quality of studies, including research designs, sampling methods, follow-up intervals and outcome measures, ranged widely. Future research should align methodologically with previous work to facilitate meta-analytic synthesis of results. Opening a new retailer may result in modest short-term increases in fruit and vegetable consumption among adults who choose to shop there, but the potential longer-term dietary impact on customers and its impact on the broader community remain unclear.

Initial Expansion of C4 Vegetation in Australia During the Late Pliocene

NASA Astrophysics Data System (ADS)

Andrae, J. W.; McInerney, F. A.; Polissar, P. J.; Sniderman, J. M. K.; Howard, S.; Hall, P. A.; Phelps, S. R.

2018-05-01

Since the late Miocene, plants using the C4 photosynthetic pathway have increased to become major components of many tropical and subtropical ecosystems. However, the drivers for this expansion remain under debate, in part because of the varied histories of C4 vegetation on different continents. Australia hosts the highest dominance of C4 vegetation of all continents, but little is known about the history of C4 vegetation there. Carbon isotope ratios of plant waxes from scientific ocean drilling sediments off north-western Australia reveal the onset of Australian C4 expansion at 3.5 Ma, later than in many other regions. Pollen analysis from the same sediments reveals increasingly open C3-dominated biomes preceding the shift to open C4-dominated biomes by several million years. We hypothesize that the development of a summer monsoon climate beginning in the late Pliocene promoted a highly seasonal precipitation regime favorable to the expansion of C4 vegetation.

Exploring the Role of Humans and Climate over the Balkan Landscape: 500 Years of Vegetational History of Serbia

NASA Technical Reports Server (NTRS)

Kulkarni, Charuta; Peteet, Dorothy; Boger, Rebecca; Heusser, Linda

2016-01-01

We present the first, well-dated, high-resolution record of vegetation and landscape change from Serbia, which spans the past 500 years. Biological proxies (pollen, spores, and charcoal), geochemical analysis through X-ray Fluorescence (XRF), and a detailed chronology based on AMS C-14 dating from a western Serbian sinkhole core suggest complex woodland-grassland dynamics and strong erosional signals throughout the Little Ice Age (LIA). An open landscape with prominent steppe vegetation (e.g. Poaceae, Chenopodiaceae) and minor woodland exists during 1540-1720 CE (early LIA), while the late LIA (1720-1850 CE) in this record shows higher tree percentages possibly due to increased moisture availability. The post LIA Era (1850-2012 CE) brings a disturbed type of vegetation with the presence of weedy genera and an increase in regional woodland. Anthropogenic indicators for agricultural, pastoral and fire practices in the region together attest to the dominant role of humans in shaping this Balkan landscape throughout the interval. The changing nature of human interference, potentially as a response to underlying climatic transitions, is evident through large-scale soil depletion resulting from grazing and land clearance during the early LIA and stabilization of arable lands during the late and post-LIA eras.

Vegetation types on acid soils of Micronesia

Treesearch

Marjorie C. Falanruw; Thomas G.. Cole; Craig D. Whitesell

1987-01-01

The soils and vegetation of the Caroline high islands, Federated States of Micronesia, are being mapped by the U.S. Department of Agriculture's Forest Service and Soil Conservation Service. By the end of 1987, vegetation maps and reports on Kosrae, Pohnpei, Yap, four Truk Islands, and Palau are expected to be available. To compare soil types with vegetation types...

Bat activity in harvested and intact forest stands in the allegheny mountains

USGS Publications Warehouse

Owen, S.F.; Menzel, M.A.; Edwards, J.W.; Ford, W.M.; Menzel, J.M.; Chapman, B.R.; Wood, P.B.; Miller, K.V.

2004-01-01

We used Anabat acoustical monitoring devices to examine bat activity in intact canopy forests, complex canopy forests with gaps, forests subjected to diameter-limit harvests, recent deferment harvests, clearcuts and unmanaged forested riparian areas in the Allegheny Mountains of West Virginia in the summer of 1999. We detected eight species of bats, including the endangered Indiana bat (Myotis sodalis). Most bat activity was concentrated in forested riparian areas. Among upland habitats, activity of silver-haired bats (Lasionycteris noctivagans) and hoary bats (Lasiurus cinereus) was higher in open, less cluttered vegetative types such as recent deferment harvests and clearcuts. Our results suggest that bat species in the central Appalachians partially segregate themselves among vegetative conditions based on differences in body morphology and echolocation call characteristics. From the standpoint of conserving bat foraging habitat for the maximum number of species in the central Appalachians, special emphasis should be placed on protecting forested riparian areas.

Habitat use by sympatric species of Eutamias

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharples, F.E.

1983-11-01

Differences in habitat use were investigated for four species of chipmunk (Eutamias amoenus, E. speciosus, E. senex, and E. quadrimaculatus) that occupy overlapping areas of roughly equal elevation in the northern Sierra Nevada. Livetrapping on six study plots was conducted over a 3-year period. Differences in vegetation structure among plots were quantified, and factors correlated with occurrence of each chipmunk species were identified by discriminant analysis. Three of the congeners appeared to exhibit preferences for different habitats. Only E. senex was found in closed-canopy forest. E. speciosus was associated only with areas of scattered trees. E. amoenus was almost themore » exclusive resident of brush plots and other disturbed areas but overlapped extensively with E. speciosus in open forest. The data suggest that the existence of different vegetational types accommodates overlapping occurrence of these species within a single altitudinal zone.« less

Pinon and Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions

USGS Publications Warehouse

Tausch, R.J.; Miller, R.F.; Roundy, B.A.; Chambers, J.C.

2009-01-01

Pinon-juniper woodlands are an important vegetation type in the Great Basin. Old-growth and open shrub savanna woodlands have been present over much of the last several hundred years. Strong evidence indicates these woodlands have experienced significant tree infilling and major expansion in their distribution since the late 1800s by encroaching into surrounding landscapes once dominated by shrubs and herbaceous vegetation. Both infilling and expansion affects soil resources, plant community structure and composition, water and nutrient cycles, forage production, wildlife habitat, biodiversity, and fire patterns across the landscape. Another impact is the shift from historic fire regimes to larger and more intense wildfires that are increasingly determining the future of this landscape. This publication helps biologists and land managers consider how to look at expansion of woodlands and determine what questions to ask to develop a management strategy, including prescribed fire or other practices.

Paleobiology of the Sand Beneath the Valders Diamicton at Valders, Wisconsin

USGS Publications Warehouse

Maher, L.J.; Miller, N.G.; Baker, R.G.; Curry, B. Brandon; Mickelson, D.M.

1998-01-01

Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty sand and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,200 14C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the red-brown diamicton of the Valders Member of the Kewaunee Formation. Fluctuations of abundance of Candona subtriangulata, Cytherissa lacustris, and three other species define four ostracode biozones in the lower 1.7 m, suggesting an open lake environment that oscillated in depth and proximity to glacial ice. Pollen is dominated by Picea and Artemisia, but the low percentages of many other types of longdistance origin suggest that the terrestrial vegetation was open and far from the forest border. The upper part of the sediment, a massive sand deposited in either a shallow pond or a sluggish stream, contains a local concentration of plant macrofossils. The interpretation of a cold open environment is supported by the plant macrofossils of more than 20 species, dominated by those of open mineral soils (Arenaria rubella, Cerastium alpinum type, Silene acaulis, Sibbaldia procumbens, Dryas integrifolia, Vaccinium uliginosum var. alpinum, Armeria maritima, etc.) that in North America occur largely in the tundra and open tundra-forest ecotone of northern Canada. Ice-wedge casts occur in the sand. ?? 1998 University of Washington.

Urban Morphological Dynamics in Santiago (chile): Proposing Sustainable Indicators from Remote Sensing

NASA Astrophysics Data System (ADS)

Hernández, H. J.; Gutiérrez, M. A.; Acuña, M. P.

2016-06-01

Latin America is one of the world's most urbanised regions, with more than 80% of inhabitants living in urban areas and over 50 cities with at least 1 million inhabitants. The concept of urban structure types (UST) allows the dynamics of a growing urban environment to be captured in its quantity and quality. They are defined as areas of homogenous appearance in the urban matrix with a recognisable mixture of built-up areas and open spaces. We used the vegetation-impervious-soil (V-I-S) model approach to classify and monitor different types of USTs in Santiago (~800 km2), Chile between 1985 and 2015. The V-I-S model is based on a simplification of the large diversity of urban land cover types in three general categories: vegetation, impervious surfaces and soil. These categories were obtained by processing Landsat-5 TM and Landsat-8 OLI images. First, we applied standard radiometric calibration and co-registration methods to all datasets. Second, using a linear spectral unmixing algorithm we performed a soft classification of urban land cover types (end members): trees, shrubs, herbaceous plants, soils, buildings, roads and water bodies. All end members were validated using a combination of photointerpretation on high-resolution images (~1 m) and field data collection (only for 2015). In each pixel we used the resulting probability scores, logically grouped, to obtain final values for each V-I-S component. Third, we used statistical clustering of V-I-S values to create a set of eight pixel groups, which we interpreted as USTs and mapped them for each date. The overall accuracy for V-I-S components in 1985 and 2015 were 78% and 82%, respectively, and errors did not exhibit any spatial correlation. The main sources of differentiation between USTs were the trade-off proportions between vegetation and impervious components, whereas soil proportions remained near 5% across the city in both dates. To analyse the change in UST spatial configuration between dates, we used a set of selected landscape metrics and discussed their use as indicators for sustainable urban development. These indicators relate to the dispersion pattern of urban growth, the connectivity of open green space and the complexity in the composition of the UST types within the different sectors of the city. We were able to identify, using the dynamics exhibited by the USTs, three main zones: (1) city centre, where USTs of high-intensity development predominate, (2) eastern high-income areas whose spatial structure is marked by a relatively high urbanisation intensity with a very large proportion of vegetated spaces, and (3) peripheral areas, with significant changes in composition and configuration of USTs, in recent decades, showing high rates of urbanisation, shifting from low-medium to high densities. We concluded that these patterns and their dynamics are mainly determined by the spatial socio-economic stratification of the population.

The present flora and vegetation of the moraines of the Klutlan Glacier, Yukon Territory, Canada: A study in plant succession*1

NASA Astrophysics Data System (ADS)

Birks, H. J. B.

1980-07-01

The flora and vegetation of six ice-cored moraines of the Klutlan Glacier were analyzed in 65 plots by European plant-sociological techniques. The age of each plot was estimated from annual growth rings of shrubs or trees in the plots. Nine major vegetation types are distinguished: Crepis nana, Dryas drummondii, Hedysarum mackenzii, Hedysarum-Salix, Salix-Shepherdia canadensis, Picea-Salix, Picea-Arctostaphylos, Picea-Ledum, and Picea-Rhytidium. These contain plants aged 2-6, 9-23, 10-20, 24-30, 32-58, 58-80, 96-178, 177-240, and >163- >339 yr, respectively. Six other vegetation types are described from windthrow areas, drainage channels, volcanic tephra slopes, lake margins, fens, and drained lakes. The major vegetation types reflect a vegetational succession related to moraine age and stability, with the Crepis nana type as the pioneer vegetation developing through the other vegetation types to the Picea-Rhytidium type on the oldest moraines. Changes in species diversity and soil development, particularly humus accumulation, parallel the vegetational succession. This succession differs from patterns of revegetation of deglaciated landscapes in Alaska and British Columbia today and in Minnesota in late-Wisconsin times because of differences in climate, plant migration, and local ecology.

Spatial variability in soil organic carbon in a tropical montane landscape: associations between soil organic carbon and land use, soil properties, vegetation, and topography vary across plot to landscape scales

NASA Astrophysics Data System (ADS)

de Blécourt, Marleen; Corre, Marife D.; Paudel, Ekananda; Harrison, Rhett D.; Brumme, Rainer; Veldkamp, Edzo

2017-08-01

Presently, the lack of data on soil organic carbon (SOC) stocks in relation to land-use types and biophysical characteristics prevents reliable estimates of ecosystem carbon stocks in montane landscapes of mainland SE Asia. Our study, conducted in a 10 000 ha landscape in Xishuangbanna, SW China, aimed at assessing the spatial variability in SOC concentrations and stocks, as well as the relationships of SOC with land-use types, soil properties, vegetation characteristics and topographical attributes at three spatial scales: (1) land-use types within a landscape (10 000 ha), (2) sampling plots (1 ha) nested within land-use types (plot distances ranging between 0.5 and 12 km), and (3) subplots (10 m radius) nested within sampling plots. We sampled 27 one-hectare plots - 10 plots in mature forests, 11 plots in regenerating or highly disturbed forests, and 6 plots in open land including tea plantations and grasslands. We used a sampling design with a hierarchical structure. The landscape was first classified according to land-use types. Within each land-use type, sampling plots were randomly selected, and within each plot we sampled within nine subplots. SOC concentrations and stocks did not differ significantly across the four land-use types. However, within the open-land category, SOC concentrations and stocks in grasslands were higher than in tea plantations (P < 0.01 for 0-0.15 m, P = 0.05 for 0.15-0.30 m, P = 0.06 for 0-0.9 m depth). The SOC stocks to a depth of 0.9 m were 177.6 ± 19.6 (SE) Mg C ha-1 in tea plantations, 199.5 ± 14.8 Mg C ha-1 in regenerating or highly disturbed forests, 228.6 ± 19.7 Mg C ha-1 in mature forests, and 236.2 ± 13.7 Mg C ha-1 in grasslands. In this montane landscape, variability within plots accounted for more than 50 % of the overall variance in SOC stocks to a depth of 0.9 m and the topsoil SOC concentrations. The relationships of SOC concentrations and stocks with land-use types, soil properties, vegetation characteristics, and topographical attributes varied across spatial scales. Variability in SOC within plots was determined by litter layer carbon stocks (P < 0.01 for 0-0.15 m and P = 0.03 for 0.15-0.30 and 0-0.9 m depth) and slope (P ≤ 0.01 for 0-0.15, 0.15-0.30, and 0-0.9 m depth) in open land, and by litter layer carbon stocks (P < 0.001 for 0-0.15, 0.15-0.30 and 0-0.9 m depth) and tree basal area (P < 0.001 for 0-0.15 m and P = 0.01 for 0-0.9 m depth) in forests. Variability in SOC among plots in open land was related to the differences in SOC concentrations and stocks between grasslands and tea plantations. In forests, the variability in SOC among plots was associated with elevation (P < 0.01 for 0-0.15 m and P = 0.09 for 0-0.9 m depth). The scale-dependent relationships between SOC and its controlling factors demonstrate that studies that aim to investigate the land-use effects on SOC need an appropriate sampling design reflecting the controlling factors of SOC so that land-use effects will not be masked by the variability between and within sampling plots.

Using ecological forecasting of future vegetation transition and fire frequency change in the Sierra Nevada to assess fire management strategies

NASA Astrophysics Data System (ADS)

Thorne, J. H.; Schwartz, M. W.; Holguin, A. J.; Moritz, M.; Batllori, E.; Folger, K.; Nydick, K.

2013-12-01

Ecological systems may respond in complex manners as climate change progresses. Among the responses, site-level climate conditions may cause a shift in vegetation due to the physiological tolerances of plant species, and the fire return interval may change. Natural resource managers challenged with maintaining ecosystem health need a way to forecast how these processes may affect every location, in order to determine appropriate management actions and prioritize locations for interventions. We integrated climate change-driven vegetation type transitions with projected change in fire frequency for 45,203 km2 of the southern Sierra Nevada, California, containing over 10 land management agencies as well as private lands. This Magnitude of Change (MOC) approach involves classing vegetation types in current time according to their climate envelopes, and identifying which sites will in the future have climates beyond what that vegetation currently occurs in. Independently, fire models are used to determine the change in fire frequency for each site. We examined 82 vegetation types with >50 grid cell occurrences. We found iconic resources such as the giant sequoia, lower slope oak woodlands, and high elevation conifer forests are projected as highly vulnerable by models that project a warmer drier future, but not as much by models that project a warmer future that is not drier than current conditions. Further, there were strongly divergent vulnerabilities of these forest types across land ownership (National Parks versus US Forest Service lands), and by GCM. For example, of 50 giant sequoia (Sequoiadendron giganteum) groves and complexes, all but 3 (on Sierra National Forest) were in the 2 highest levels of risk of climate and fire under the GFDL A2 projection, while 15 groves with low-to-moderate risk were found on both the National Parks and National Forests 18 in the 2 under PCM A2. Landscape projections of potential MOC suggest that the region is likely to experience strong upslope shifting of open grassland, chaparral and hardwood types, which may be initiated by increased fire frequencies, particularly where fires have not recently burned within normal fire recurrence interval departures (FRID). An evaluation of four fire management strategies (business as usual; resist change; foster orderly change; protect vital resources) across four combinations of future climate and fire frequency found that no single management strategy was uniformly successful in protecting critical resources across the range of future conditions examined. This limitation is somewhat driven by current management constraints on the amount of management available to resource managers, which suggests management will need to use a triage approach to application of proactive fire management strategies, wherein MOC landscape projections can be used in decision support.

Effects of late Holocene climate variability and anthropogenic stressors on the vegetation of the Maya highlands

NASA Astrophysics Data System (ADS)

Franco-Gaviria, F.; Correa-Metrio, A.; Cordero-Oviedo, C.; López-Pérez, M.; Cárdenes-Sandí, G. M.; Romero, F. M.

2018-06-01

Climate variability and human activities have shaped the vegetation communities of the Maya region of southern Mexico and Central America on centennial to millennial timescales. Most research efforts in the region have focused on the lowlands, with relatively little known about the environmental history of the regional highlands. Here we present data from two sediment sequences collected from lakes in the highlands of Chiapas, Mexico. Our aim was to disentangle the relative contributions of climate and human activities in the development of regional vegetation during the late Holocene. The records reveal a long-term trend towards drier conditions with superimposed centennial-scale droughts. A declining moisture trend from 3400 to 1500 cal yr BP is consistent with previously reported southward displacement of the Intertropical Convergence Zone, whereas periodic droughts were probably a consequence of drivers such as El Niño. These conditions, together with dense human occupation, converted the vegetation from forest to more open systems. According to the paleoecological records, cultural abandonment of the area occurred ca. 1500 cal yr BP, favoring forest recovery that was somewhat limited by low moisture availability. About 600 cal yr BP, wetter conditions promoted the establishment of modern montane cloud forests, which consist of a diverse mixture of temperate and tropical elements. The vegetation types that occupied the study area during the last few millennia have remained within the envelope defined by the modern vegetation mosaic. This finding highlights the importance of microhabitats in the maintenance biodiversity through time, even under scenarios of high climate variability and anthropogenic pressure.

Local habitat and landscape influence predation of bird nests on afforested Mediterranean cropland

NASA Astrophysics Data System (ADS)

Sánchez-Oliver, J. S.; Rey Benayas, J. M.; Carrascal, L. M.

2014-07-01

Afforestation programs such as the one promoted by the EU Common Agrarian Policy have contributed to spread tree plantations on former cropland. Nevertheless these afforestations may cause severe damage to open habitat species, especially birds of high conservation value. We investigated predation of artificial bird nests at young tree plantations and at the open farmland habitat adjacent to the tree plantations in central Spain. Predation rates were very high at both tree plantations (95.6%) and open farmland habitat (94.2%) after two and three week exposure. Plantation edge/area ratio and development of the tree canopy decreased predation rates and plantation area and magpie (Pica pica) abundance increased predation rates within tree plantations, which were also affected by land use types around plantations. The area of nearby tree plantations (positive effect), distance to the tree plantation edge (negative effect), and habitat type (mainly attributable to the location of nests in vineyards) explained predation rates at open farmland habitat. We conclude that predation rates on artificial nests were particularly high and rapid at or nearby large plantations, with high numbers of magpies and low tree development, and located in homogenous landscapes dominated by herbaceous crops and pastures with no remnants of semi-natural woody vegetation. Landscape planning should not favour tree plantations as the ones studied here in Mediterranean agricultural areas that are highly valuable for ground-nesting bird species.

New vegetation type map of India prepared using satellite remote sensing: Comparison with global vegetation maps and utilities

NASA Astrophysics Data System (ADS)

Roy, P. S.; Behera, M. D.; Murthy, M. S. R.; Roy, Arijit; Singh, Sarnam; Kushwaha, S. P. S.; Jha, C. S.; Sudhakar, S.; Joshi, P. K.; Reddy, Ch. Sudhakar; Gupta, Stutee; Pujar, Girish; Dutt, C. B. S.; Srivastava, V. K.; Porwal, M. C.; Tripathi, Poonam; Singh, J. S.; Chitale, Vishwas; Skidmore, A. K.; Rajshekhar, G.; Kushwaha, Deepak; Karnatak, Harish; Saran, Sameer; Giriraj, A.; Padalia, Hitendra; Kale, Manish; Nandy, Subrato; Jeganathan, C.; Singh, C. P.; Biradar, C. M.; Pattanaik, Chiranjibi; Singh, D. K.; Devagiri, G. M.; Talukdar, Gautam; Panigrahy, Rabindra K.; Singh, Harnam; Sharma, J. R.; Haridasan, K.; Trivedi, Shivam; Singh, K. P.; Kannan, L.; Daniel, M.; Misra, M. K.; Niphadkar, Madhura; Nagabhatla, Nidhi; Prasad, Nupoor; Tripathi, O. P.; Prasad, P. Rama Chandra; Dash, Pushpa; Qureshi, Qamer; Tripathi, S. K.; Ramesh, B. R.; Gowda, Balakrishnan; Tomar, Sanjay; Romshoo, Shakil; Giriraj, Shilpa; Ravan, Shirish A.; Behera, Soumit Kumar; Paul, Subrato; Das, Ashesh Kumar; Ranganath, B. K.; Singh, T. P.; Sahu, T. R.; Shankar, Uma; Menon, A. R. R.; Srivastava, Gaurav; Neeti; Sharma, Subrat; Mohapatra, U. B.; Peddi, Ashok; Rashid, Humayun; Salroo, Irfan; Krishna, P. Hari; Hajra, P. K.; Vergheese, A. O.; Matin, Shafique; Chaudhary, Swapnil A.; Ghosh, Sonali; Lakshmi, Udaya; Rawat, Deepshikha; Ambastha, Kalpana; Malik, Akhtar H.; Devi, B. S. S.; Gowda, Balakrishna; Sharma, K. C.; Mukharjee, Prashant; Sharma, Ajay; Davidar, Priya; Raju, R. R. Venkata; Katewa, S. S.; Kant, Shashi; Raju, Vatsavaya S.; Uniyal, B. P.; Debnath, Bijan; Rout, D. K.; Thapa, Rajesh; Joseph, Shijo; Chhetri, Pradeep; Ramachandran, Reshma M.

2015-07-01

A seamless vegetation type map of India (scale 1: 50,000) prepared using medium-resolution IRS LISS-III images is presented. The map was created using an on-screen visual interpretation technique and has an accuracy of 90%, as assessed using 15,565 ground control points. India has hitherto been using potential vegetation/forest type map prepared by Champion and Seth in 1968. We characterized and mapped further the vegetation type distribution in the country in terms of occurrence and distribution, area occupancy, percentage of protected area (PA) covered by each vegetation type, range of elevation, mean annual temperature and precipitation over the past 100 years. A remote sensing-amenable hierarchical classification scheme that accommodates natural and semi-natural systems was conceptualized, and the natural vegetation was classified into forests, scrub/shrub lands and grasslands on the basis of extent of vegetation cover. We discuss the distribution and potential utility of the vegetation type map in a broad range of ecological, climatic and conservation applications from global, national and local perspectives. We used 15,565 ground control points to assess the accuracy of products available globally (i.e., GlobCover, Holdridge's life zone map and potential natural vegetation (PNV) maps). Hence we recommend that the map prepared herein be used widely. This vegetation type map is the most comprehensive one developed for India so far. It was prepared using 23.5 m seasonal satellite remote sensing data, field samples and information relating to the biogeography, climate and soil. The digital map is now available through a web portal (http://bis.iirs.gov.in).

Local and landscape drivers of predation services in urban gardens.

PubMed

Philpott, Stacy M; Bichier, Peter

2017-04-01

In agroecosystems, local and landscape features, as well as natural enemy abundance and richness, are significant predictors of predation services that may result in biological control of pests. Despite the increasing importance of urban gardening for provisioning of food to urban populations, most urban gardeners suffer from high pest problems, and have little knowledge about how to manage their plots to increase biological control services. We examined the influence of local, garden scale (i.e., herbaceous and arboreal vegetation abundance and diversity, ground cover) and landscape (i.e., landscape diversity and surrounding land use types) characteristics on predation services provided by naturally occurring predators in 19 urban gardens in the California central coast. We introduced sentinel pests (moth eggs and larvae and pea aphids) onto greenhouse-raised plants taken to gardens and assigned to open or bagged (predator exclosure) treatments. We found high predation rates with between 40% and 90% of prey items removed in open treatments. Predation services varied with local and landscape factors, but significant predictors differed by prey species. Predation of eggs and aphids increased with vegetation complexity in gardens, but larvae predation declined with vegetation complexity. Smaller gardens experienced higher predation services, likely due to increases in predator abundance in smaller gardens. Several ground cover features influenced predation services. In contrast to patterns in rural agricultural landscapes, predation on aphids declined with increases in landscape diversity. In sum, we report the relationships between several local management factors, as well as landscape surroundings, and implications for garden management. © 2017 by the Ecological Society of America.

Remote sensing-based characterization, 2-m, Plant Functional Type Distributions, Barrow Environmental Observatory, 2010

DOE Data Explorer

Langford, Zachary; Kumar, Jitendra; Hoffman, Forrest

2014-01-01

Arctic ecosystems have been observed to be warming faster than the global average and are predicted to experience accelerated changes in climate due to global warming. Arctic vegetation is particularly sensitive to warming conditions and likely to exhibit shifts in species composition, phenology and productivity under changing climate. Mapping and monitoring of changes in vegetation is essential to understand the effect of climate change on the ecosystem functions. Vegetation exhibits unique spectral characteristics which can be harnessed to discriminate plant types and develop quantitative vegetation indices. We have combined high resolution multi-spectral remote sensing from the WorldView 2 satellite with LIDAR-derived digital elevation models to characterize the tundra landscape on the North Slope of Alaska. Classification of landscape using spectral and topographic characteristics yields spatial regions with expectedly similar vegetation characteristics. A field campaign was conducted during peak growing season to collect vegetation harvests from a number of 1m x 1m plots in the study region, which were then analyzed for distribution of vegetation types in the plots. Statistical relationships were developed between spectral and topographic characteristics and vegetation type distributions at the vegetation plots. These derived relationships were employed to statistically upscale the vegetation distributions for the landscape based on spectral characteristics. Vegetation distributions developed are being used to provide Plant Functional Type (PFT) maps for use in the Community Land Model (CLM).

Role of invasive Melilotus officinalis in two native plant communities

USGS Publications Warehouse

Van Riper, Laura C.; Larson, Diane L.

2009-01-01

This study examines the impact of the exotic nitrogen-fixing legume Melilotus officinalis (L.) Lam. on native and exotic species cover in two Great Plains ecosystems in Badlands National Park, South Dakota. Melilotus is still widely planted and its effects on native ecosystems are not well studied. Melilotus could have direct effects on native plants, such as through competition or facilitation. Alternatively, Melilotus may have indirect effects on natives, e.g., by favoring exotic species which in turn have a negative effect on native species. This study examined these interactions across a 4-year period in two contrasting vegetation types: Badlands sparse vegetation and western wheatgrass (Pascopyrum smithii) mixed-grass prairie. Structural equation models were used to analyze the pathways through which Melilotus, native species, and other exotic species interact over a series of 2-year time steps. Melilotus can affect native and exotic species both in the current year and in the years after its death (a lag effect). A lag effect is possible because the death of a Melilotus plant can leave an open, potentially nitrogen-enriched site on the landscape. The results showed that the relationship between Melilotus and native and exotic species varied depending on the habitat and the year. In Badlands sparse vegetation, there was a consistent, strong, and positive relationship between Melilotus cover and native and exotic species cover suggesting that Melilotus is acting as a nurse plant and facilitating the growth of other species. In contrast, in western wheatgrass prairie, Melilotus was acting as a weak competitor and had no consistent effect on other species. In both habitats, there was little evidence for a direct lag effect of Melilotus on other species. Together, these results suggest both facilitative and competitive roles for Melilotus, depending on the vegetation type it invades.

Higher intake of fruits, vegetables or their fiber reduces the risk of type 2 diabetes: A meta-analysis.

PubMed

Wang, Ping-Yu; Fang, Jun-Chao; Gao, Zong-Hua; Zhang, Can; Xie, Shu-Yang

2016-01-01

Some previous studies reported no significant association of consuming fruit or vegetables, or fruit and vegetables combined, with type 2 diabetes. Others reported that only a greater intake of green leafy vegetables reduced the risk of type 2 diabetes. To further investigate the relationship between them, we carried out a meta-analysis to estimate the independent effects of the intake of fruit, vegetables and fiber on the risk of type 2 diabetes. Searches of MEDLINE and EMBASE for reports of prospective cohort studies published from 1 January 1966 to 21 July 2014 were carried out, checking reference lists, hand-searching journals and contacting experts. The primary analysis included a total of 23 (11 + 12) articles. The pooled maximum-adjusted relative risk of type 2 diabetes for the highest intake vs the lowest intake were 0.91 (95% confidence interval [CI] 0.87-0.96) for total fruits, 0.75 (95% CI 0.66-0.84) for blueberries, 0.87 (95% CI 0.81-0.93) for green leafy vegetables, 0.72 (95% CI 0.57-0.90) for yellow vegetables, 0.82 (95% CI 0.67-0.99) for cruciferous vegetables and 0.93 (95% CI 0.88-0.99) for fruit fiber in these high-quality studies in which scores were seven or greater, and 0.87 (95% CI 0.80-0.94) for vegetable fiber in studies with a follow-up period of 10 years or more. A higher intake of fruit, especially berries, and green leafy vegetables, yellow vegetables, cruciferous vegetables or their fiber is associated with a lower risk of type 2 diabetes.

Thirty Thousand Years of Vegetation Changes in the Alabama Hills, Owens Valley, California

NASA Astrophysics Data System (ADS)

Koehler, Peter A.; Anderson, R. Scott

1995-03-01

Twenty packrat ( Neotoma) middens recovered from three sites (1265-1535 m) in the Alabama Hills, Inyo County, California, provide a ca. 31,450-yr record of vegetation change. Located ca. 7 km east of the Sierra Nevada, the middens document that Utah juniper ( Juniperus osteosperma), Joshua tree ( Yucca brevifolia), and bitterbush ( Purshia tridentata) occupied the site between 31,450 and 19,070 yr B.P. Joshua tree and bitterbush departed by ca. 17,760 yr B.P., with cliffrose ( Purshia mexicana) and joint-fir ( Ephedra viridis) appearing. By 13,350 yr B.P., blackbush ( Coleogyne ramosissima) and cholla ( Opuntia echinocarpa) entered the record. Between 9540 and 7990 yr B.P., Utah juniper and other species now extralocal to the sites departed and modern components such as wolfberry ( Lycium andersonii) and rubber rabbitbrush ( Chrysothamnus teretifolius) appeared. The middle Holocene records little variation in plant macrofossil composition; however, pollen analysis reflects an increase in aquatic pollen types which might suggest more-open conditions. The transition to the modern vegetation associations at the sites occurred after ca. 2800 yr B.P. The record from the Alabama Hills correlates well with that of other regional vegetation data but documents conditions of increasing aridity earlier than many other packrat midden sites. A shift in understory vegetation between 19,070 and 17,760 yr B.P. may reflect a transition from glacial maximum to post-maximum conditions in the eastern Sierra Nevada.

Applications of Remote Sensing for Studying Lateral Carbon Fluxes and Inundation Dynamics in Tidal Wetlands

NASA Astrophysics Data System (ADS)

Lamb, B. T.; Tzortziou, M.; McDonald, K. C.

2017-12-01

Wetlands play a key role in Earth's carbon cycle. However, wetland carbon cycling exhibits a high level of spatiotemporal dynamism, and thus, is not as well understood as carbon cycling in other ecosystems. In order to accurately characterize wetland carbon cycling and fluxes, wetland vegetation phenology, seasonal inundation dynamics, and tidal regimes must be understood as these factors influence carbon generation and transport. Here, we use radar remote sensing to map wetland properties in the Chesapeake Bay, the largest estuary in the United States with more than 1,500 square miles of tidal wetlands, across a range of tidal amplitudes, salinity regimes, and soil organic matter content levels. We have been using Sentinel-1 and ALOS PALSAR-1 radar measurements to characterize vegetation and seasonal inundation dynamics with the future goal of characterizing salinity gradients and tidal regimes. Differences in radar backscatter from various surface targets has been shown to effectively discriminate between dry soil, wet soil, vegetated areas, and open water. Radar polarization differences and ratios are particularly effective at distinguishing between vegetated and non-vegetated areas. Utilizing these principles, we have been characterizing wetland types using supervised classification techniques including: Random Forest, Maximum Likelihood, and Minimum Distance. The National Wetlands Inventory has been used as training and validation data. Ideally, the techniques we outline in this research will be applicable to the characterization of wetlands in coastal areas outside of Chesapeake Bay.

Fruit and vegetable intake and risk of type 2 diabetes mellitus: meta-analysis of prospective cohort studies

PubMed Central

Li, Min; Fan, Yingli; Zhang, Xiaowei; Hou, Wenshang; Tang, Zhenyu

2014-01-01

Objective To clarify and quantify the potential dose–response association between the intake of fruit and vegetables and risk of type 2 diabetes. Design Meta-analysis and systematic review of prospective cohort studies. Data source Studies published before February 2014 identified through electronic searches using PubMed and Embase. Eligibility criteria for selecting studies Prospective cohort studies with relative risks and 95% CIs for type 2 diabetes according to the intake of fruit, vegetables, or fruit and vegetables. Results A total of 10 articles including 13 comparisons with 24 013 cases of type 2 diabetes and 434 342 participants were included in the meta-analysis. Evidence of curve linear associations was seen between fruit and green leafy vegetables consumption and risk of type 2 diabetes (p=0.059 and p=0.036 for non-linearity, respectively). The summary relative risk of type 2 diabetes for an increase of 1 serving fruit consumed/day was 0.93 (95% CI 0.88 to 0.99) without heterogeneity among studies (p=0.477, I2=0%). For vegetables, the combined relative risk of type 2 diabetes for an increase of 1 serving consumed/day was 0.90 (95% CI 0.80 to 1.01) with moderate heterogeneity among studies (p=0.002, I2=66.5%). For green leafy vegetables, the summary relative risk of type 2 diabetes for an increase of 0.2 serving consumed/day was 0.87 (95% CI 0.81 to 0.93) without heterogeneity among studies (p=0.496, I2=0%). The combined estimates showed no significant benefits of increasing the consumption of fruit and vegetables combined. Conclusions Higher fruit or green leafy vegetables intake is associated with a significantly reduced risk of type 2 diabetes. PMID:25377009

Inventory and monitoring of natural vegetation and related resources in an arid environment: A comprehensive evaluation of ERTS-1 imagery. [Arizona

NASA Technical Reports Server (NTRS)

Schrumpf, B. J. (Principal Investigator); Johnson, J. R.; Mouat, D. A.; Pyott, W. T.

1974-01-01

The author has identified the following significant results. A vegetation classification, with 31 types and compatible with remote sensing applications, was developed for the test site. Terrain features can be used to discriminate vegetation types. Elevation and macrorelief interpretations were successful on ERTS photos, although for macrorelief, high sun angle stereoscopic interpretations were better than low sun angle monoscopic interpretations. Using spectral reflectivity, several vegetation types were characterized in terms of patterns of signature change. ERTS MSS digital data were used to discriminate vegetation classes at the association level and at the alliance level when image contrasts were high or low, respectively. An imagery comparison technique was developed to test image complexity and image groupability. In two stage sampling of vegetation types, ERTS plus high altitude photos were highly satisfactory for estimating kind and extent of types present, and for providing a mapping base.

Nesting habitat of the Tule Greater White-fronted Goose Anser albifrons elgasi

USGS Publications Warehouse

Densmore, R.V.; Ely, Craig R.; Bollinger, K.S.; Kratzer, S.; Udevitz, M.S.; Fehringer, D.J.; Rothe, T.C.

2006-01-01

This paper presents the first information on the availability and use of nesting habitat by the rare Tule Greater White-fronted Goose Anser albifrons elgasi. The breeding range was sampled by marking geese with radio transmitters on wintering and moulting areas, and tracking them to nest sites in Alaska. Nesting habitat was described at the scales of ecoregion, wetland ecosystem (National Wetlands Inventory (NWI) maps), vegetation type within wetland (Alaska Vegetation Classification (AVC) maps based on satellite imagery), and nest site. Tule Greater White-fronted Goose nests were located in boreal forest wetlands in the upper Cook Inlet Basin ecoregion. Nesting Tule Greater White-fronted Geese selected NWT Palustrine Seasonally Flooded wetlands and used NWI Palustrine Saturated wetlands in proportion to availability. Within these wetlands, Tule Greater White-fronted Geese used Needleleaf Forest, Low Shrub and Herbaceous (mostly graminoid) AVC classes for nest sites in proportion to availability Most (93%) Tule Greater White-fronted Geese nested > 75 m from open water ponds or lakes, and many nested in wetlands with little or no open water. Tule Greater White-fronted Geese nest only in a small breeding area near the most human-impacted area of the state, and continued development may limit the use of suitable nesting habitat.

[Responses of alpine grassland landscape in the source region of Shule River Basin to topographical factors and frozen ground types].

PubMed

Chen, Jian-Jun; Yi, Shu-Hua; Qin, Yu; Wang, Xiao-Yun

2014-06-01

This paper retrieved the fractional vegetation cover of alpine grassland in the source region of the Shule River Basin based on Chinese environmental satellite (HJ-1A/1B) images and field data, and analyzed the response of the vegetation cover to topographic factors and types of frozen ground. The results showed that the vegetation coverage of this region was low with large spatial heterogeneity and high degree of dispersion. The landscape consisted mainly of non-vegetation surface types, eg. ice, snow, the bare rock gravel land and bare land. Slopes and aspects were the main limiting factors of vegetation distribution. The average vegetation coverage decreased with the increase of slope. The average vegetation coverage was the lowest on the sunny slope, and the highest on the shady slope. There were significant differences of vegetation coverage among different types of frozen ground. The distribution of vegetation coverage presented a reversed "U" curve trend by extremely stable permafrost, stable permafrost, sub-stable permafrost, transition permafrost, unstable permafrost and seasonal frost, and the average vegetation coverage was the highest in the sub-stable permafrost.

Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro.

PubMed

Rutten, Gemma; Ensslin, Andreas; Hemp, Andreas; Fischer, Markus

2015-01-01

In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866-4550 m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies.

Effect of eating vegetables before carbohydrates on glucose excursions in patients with type 2 diabetes

PubMed Central

Imai, Saeko; Fukui, Michiaki; Kajiyama, Shizuo

2014-01-01

The aim of this review was to evaluate whether eating vegetables before carbohydrates could reduce the postprandial glucose, insulin, and improve long-term glycemic control in Japanese patients with type 2 diabetes. We studied the effect of eating vegetables before carbohydrates on postprandial plasma glucose, insulin, and glycemic control for 2.5 y in patients with type 2 diabetes. The postprandial glucose and insulin levels decreased significantly when the patients ate vegetables before carbohydrates compared to the reverse regimen, and the improvement of glycemic control was observed for 2.5 y. We also compared the postprandial glucose and glucose fluctuations assessed by continuous glucose monitoring system for 72-h in patients with type 2 diabetes and subjects with normal glucose tolerance when subjects ate vegetables before carbohydrates and carbohydrates before vegetables in a randomized crossover design. The glycemic excursions and incremental glucose peak were significantly lower when the subjects ate vegetables before carbohydrates compared to the reverse regimen. This evidence supports the effectiveness of eating vegetables before carbohydrates on glucose excursions in the short-term and glycemic control in the long-term in patients with type 2 diabetes. PMID:24426184

Effect of eating vegetables before carbohydrates on glucose excursions in patients with type 2 diabetes.

PubMed

Imai, Saeko; Fukui, Michiaki; Kajiyama, Shizuo

2014-01-01

The aim of this review was to evaluate whether eating vegetables before carbohydrates could reduce the postprandial glucose, insulin, and improve long-term glycemic control in Japanese patients with type 2 diabetes. We studied the effect of eating vegetables before carbohydrates on postprandial plasma glucose, insulin, and glycemic control for 2.5 y in patients with type 2 diabetes. The postprandial glucose and insulin levels decreased significantly when the patients ate vegetables before carbohydrates compared to the reverse regimen, and the improvement of glycemic control was observed for 2.5 y. We also compared the postprandial glucose and glucose fluctuations assessed by continuous glucose monitoring system for 72-h in patients with type 2 diabetes and subjects with normal glucose tolerance when subjects ate vegetables before carbohydrates and carbohydrates before vegetables in a randomized crossover design. The glycemic excursions and incremental glucose peak were significantly lower when the subjects ate vegetables before carbohydrates compared to the reverse regimen. This evidence supports the effectiveness of eating vegetables before carbohydrates on glucose excursions in the short-term and glycemic control in the long-term in patients with type 2 diabetes.

Wildfires alter rodent community structure across four vegetation types in southern California, USA

USGS Publications Warehouse

Brehme, Cheryl S.; Clark, Denise R.; Rochester, Carlton J.; Fisher, Robert N.

2011-01-01

We surveyed burned and unburned plots across four habitat reserves in San Diego County, California, USA, in 2005 and 2006, to assess the effects of the 2003 wildfires on the community structure and relative abundance of rodent species. The reserves each contained multiple vegetation types (coastal sage scrub, chaparral, woodland, and grassland) and spanned from 250 m to 1078 m in elevation. Multivariate analyses revealed a more simplified rodent community structure in all burned habitats in comparison to unburned habitats. Reduction in shrub and tree cover was highly predictive of changes in post-fire rodent community structure in the burned coastal sage scrub and chaparral habitats. Reduction in cover was not predictive for the less substantially burned woodlands and grasslands, for which we hypothesized that interspecific competition played a greater role in post-fire community structure. Across vegetation types, generalists and open habitat specialists typically increased in relative abundance, whereas closed habitat specialists decreased. We documented significant increases in relative abundance of the deer mouse (Peromyscus maniculatus Wagner) and Dulzura kangaroo rat (Dipodomys simulans Merriam). In contrast, we found significant decreases in relative abundance for the California mouse (Peromyscus californicus Gambel), San Diego pocket mouse (Chaetodipus fallax Merriam), desert woodrat (Neotoma lepida Thomas), and brush mouse (Peromyscus boylii Baird). Currently, our research program involves assessment of whether habitat conservation plans (HCPs) in southern California provide long-term protection to HCP covered species, as well as preserve ecosystem function. The scenario of increased wildfires needs to be incorporated into this assessment. We discuss our results in relation to management and conservation planning under a future scenario of larger and more frequent wildfires in southern California.

The tri-soil experiment: do plants discriminate among vegetation soil types?

USDA-ARS?s Scientific Manuscript database

We tested if rooting mass and root nutrient uptake of cheatgrass (Bromus tectorum) or creeping wildrye (Leymus triticoides) were influenced by vegetation soil type. Three soil types (A horizons), similar in gross physical and chemical properties, were freshly-collected. The soils varied in the veget...

Estimation of vegetation-type areas by linear measurement

Treesearch

A.A. Hasel

1941-01-01

Maps are very useful in providing a picture of the location of vegetation types, but mapping as a method for determining type areas may be inadequate or costly. The measurement of vegetation type areas by means of line surveys is discussed in the following article, and the method is tested in connection with detailed studies on plots. The results indicate that the...

Developing a Carbon Monitoring System For Pinyon-juniper Forests and Woodlands

NASA Astrophysics Data System (ADS)

Falkowski, M. J.; Hudak, A. T.; Fekety, P.; Filippelli, S.

2017-12-01

Pinyon-juniper (PJ) forests and woodlands are the third largest vegetation type in the United States. They cover over 40 million hectares across the western US, representing 40% of the total forest and woodland area in the Intermountain West. Although the density of carbon stored in these ecosystems is relatively low compared to other forest types, the vast area of short stature forests and woodlands (both nationally and globally) make them critical components of regional, national, and global carbon budgets. The overarching goal of this research is to prototype a carbon monitoring, reporting, and verification (MRV) system for characterizing total aboveground biomass stocks and flux across the PJ vegetation gradient in the western United States. We achieve this by combining in situ forest measurements and novel allometric equations with tree measurements derived from high resolution airborne imagery to map aboveground biomass across 500,000 km2 in the Western US. These high-resolution maps of aboveground biomass are then leveraged as training data to predict biomass flux through time from Landsat time-series data. The results from this research highlight the potential in mapping biomass stocks and flux in open forests and woodlands, and could be easily adopted into an MRV framework.

National Park Service Vegetation Mapping Inventory Program: Appalachian National Scenic Trail vegetation mapping project

USGS Publications Warehouse

Hop, Kevin D.; Strassman, Andrew C.; Hall, Mark; Menard, Shannon; Largay, Ery; Sattler, Stephanie; Hoy, Erin E.; Ruhser, Janis; Hlavacek, Enrika; Dieck, Jennifer

2017-01-01

The National Park Service (NPS) Vegetation Mapping Inventory (VMI) Program classifies, describes, and maps existing vegetation of national park units for the NPS Natural Resource Inventory and Monitoring (I&M) Program. The NPS VMI Program is managed by the NPS I&M Division and provides baseline vegetation information to the NPS Natural Resource I&M Program. The U.S. Geological Survey Upper Midwest Environmental Sciences Center, NatureServe, NPS Northeast Temperate Network, and NPS Appalachian National Scenic Trail (APPA) have completed vegetation classification and mapping of APPA for the NPS VMI Program.Mappers, ecologists, and botanists collaborated to affirm vegetation types within the U.S. National Vegetation Classification (USNVC) of APPA and to determine how best to map the vegetation types by using aerial imagery. Analyses of data from 1,618 vegetation plots were used to describe USNVC associations of APPA. Data from 289 verification sites were collected to test the field key to vegetation associations and the application of vegetation associations to a sample set of map polygons. Data from 269 validation sites were collected to assess vegetation mapping prior to submitting the vegetation map for accuracy assessment (AA). Data from 3,265 AA sites were collected, of which 3,204 were used to test accuracy of the vegetation map layer. The collective of these datasets affirmed 280 USNVC associations for the APPA vegetation mapping project.To map the vegetation and land cover of APPA, 169 map classes were developed. The 169 map classes consist of 150 that represent natural (including ruderal) vegetation types in the USNVC, 11 that represent cultural (agricultural and developed) vegetation types in the USNVC, 5 that represent natural landscapes with catastrophic disturbance or some other modification to natural vegetation preventing accurate classification in the USNVC, and 3 that represent nonvegetated water (non-USNVC). Features were interpreted from viewing 4-band digital aerial imagery using digital onscreen three-dimensional stereoscopic workflow systems in geographic information systems (GIS). (Digital aerial imagery was collected each fall during 2009–11 to capture leaf-phenology change of hardwood trees across the latitudinal range of APPA.) The interpreted data were digitally and spatially referenced, thus making the spatial-database layers usable in GIS. Polygon units were mapped to either a 0.5-hectare (ha) or 0.25-ha minimum mapping unit, depending on vegetation type or scenario; however, polygon units were mapped to 0.1 ha for alpine vegetation.A geodatabase containing various feature-class layers and tables provide locations and support data to USNVC vegetation types (vegetation map layer), vegetation plots, verification sites, validation sites, AA sites, project boundary extent and zones, and aerial image centers and flight lines. The feature-class layer and related tables of the vegetation map layer provide 30,395 polygons of detailed attribute data covering 110,919.7 ha, with an average polygon size of 3.6 ha; the vegetation map coincides closely with the administrative boundary for APPA.Summary reports generated from the vegetation map layer of the map classes representing USNVC natural (including ruderal) vegetation types apply to 28,242 polygons (92.9% of polygons) and cover 106,413.0 ha (95.9%) of the map extent for APPA. The map layer indicates APPA to be 92.4% forest and woodland (102,480.8 ha), 1.7% shrubland (1866.3 ha), and 1.8% herbaceous cover (2,065.9 ha). Map classes representing park-special vegetation (undefined in the USNVC) apply to 58 polygons (0.2% of polygons) and cover 404.3 ha (0.4%) of the map extent. Map classes representing USNVC cultural types apply to 1,777 polygons (5.8% of polygons) and cover 2,516.3 ha (2.3%) of the map extent. Map classes representing nonvegetated water (non-USNVC) apply to 332 polygons (1.1% of polygons) and cover 1,586.2 ha (1.4%) of the map extent.

On the utilization of novel spectral laser scanning for three-dimensional classification of vegetation elements.

PubMed

Li, Zhan; Schaefer, Michael; Strahler, Alan; Schaaf, Crystal; Jupp, David

2018-04-06

The Dual-Wavelength Echidna Lidar (DWEL), a full waveform terrestrial laser scanner (TLS), has been used to scan a variety of forested and agricultural environments. From these scanning campaigns, we summarize the benefits and challenges given by DWEL's novel coaxial dual-wavelength scanning technology, particularly for the three-dimensional (3D) classification of vegetation elements. Simultaneous scanning at both 1064 nm and 1548 nm by DWEL instruments provides a new spectral dimension to TLS data that joins the 3D spatial dimension of lidar as an information source. Our point cloud classification algorithm explores the utilization of both spectral and spatial attributes of individual points from DWEL scans and highlights the strengths and weaknesses of each attribute domain. The spectral and spatial attributes for vegetation element classification each perform better in different parts of vegetation (canopy interior, fine branches, coarse trunks, etc.) and under different vegetation conditions (dead or live, leaf-on or leaf-off, water content, etc.). These environmental characteristics of vegetation, convolved with the lidar instrument specifications and lidar data quality, result in the actual capabilities of spectral and spatial attributes to classify vegetation elements in 3D space. The spectral and spatial information domains thus complement each other in the classification process. The joint use of both not only enhances the classification accuracy but also reduces its variance across the multiple vegetation types we have examined, highlighting the value of the DWEL as a new source of 3D spectral information. Wider deployment of the DWEL instruments is in practice currently held back by challenges in instrument development and the demands of data processing required by coaxial dual- or multi-wavelength scanning. But the simultaneous 3D acquisition of both spectral and spatial features, offered by new multispectral scanning instruments such as the DWEL, opens doors to study biophysical and biochemical properties of forested and agricultural ecosystems at more detailed scales.

Herbaceous Forage and Selection Patterns by Ungulates across Varying Herbivore Assemblages in a South African Savanna

PubMed Central

Treydte, Anna Christina; Baumgartner, Sabine; Heitkönig, Ignas M. A.; Grant, Catharina C.; Getz, Wayne M.

2013-01-01

Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African savanna in and adjacent to the Kruger National Park, South Africa. We compared mixed and mono-specific herbivore assemblages of varying density and investigated similarities in vegetation patterns under wildlife and livestock herbivory. Grass species composition differed significantly, standing biomass and grass height were almost twice as high at sites of low density compared to high density mixed wildlife species. Selection of various grass species by herbivores was positively correlated with greenness, nutrient content and palatability. Nutrient-rich Urochloa mosambicensis Hack. and Panicum maximum Jacq. grasses were preferred forage species, which significantly differed in abundance across sites of varying grazing pressure. Green grasses growing beneath trees were grazed more frequently than dry grasses growing in the open. Our results indicate that grazing herbivores appear to base their grass species preferences on nutrient content cues and that a characteristic grass species abundance and herb layer structure can be matched with mammalian herbivory types. PMID:24358228

Vegetation resurvey is robust to plot location uncertainty

PubMed Central

Kopecký, Martin; Macek, Martin

2017-01-01

Aim Resurveys of historical vegetation plots are increasingly used for the assessment of decadal changes in plant species diversity and composition. However, historical plots are usually relocated only approximately. This potentially inflates temporal changes and undermines results. Location Temperate deciduous forests in Central Europe. Methods To explore if robust conclusions can be drawn from resurvey studies despite location uncertainty, we compared temporal changes in species richness, frequency, composition and compositional heterogeneity between exactly and approximately relocated plots. We hypothesized that compositional changes should be lower and changes in species richness should be less variable on exactly relocated plots, because pseudo-turnover inflates temporal changes on approximately relocated plots. Results Temporal changes in species richness were not more variable and temporal changes in species composition and compositional heterogeneity were not higher on approximately relocated plots. Moreover, the frequency of individual species changed similarly on both plot types. Main conclusions The resurvey of historical vegetation plots is robust to uncertainty in original plot location and, when done properly, provides reliable evidence of decadal changes in plant communities. This provides important background for other resurvey studies and opens up the possibility for large-scale assessments of plant community change. PMID:28503083

Palaeodistribution modelling of European vegetation types at the Last Glacial Maximum using modern analogues from Siberia: Prospects and limitations

NASA Astrophysics Data System (ADS)

Janská, Veronika; Jiménez-Alfaro, Borja; Chytrý, Milan; Divíšek, Jan; Anenkhonov, Oleg; Korolyuk, Andrey; Lashchinskyi, Nikolai; Culek, Martin

2017-03-01

We modelled the European distribution of vegetation types at the Last Glacial Maximum (LGM) using present-day data from Siberia, a region hypothesized to be a modern analogue of European glacial climate. Distribution models were calibrated with current climate using 6274 vegetation-plot records surveyed in Siberia. Out of 22 initially used vegetation types, good or moderately good models in terms of statistical validation and expert-based evaluation were computed for 18 types, which were then projected to European climate at the LGM. The resulting distributions were generally consistent with reconstructions based on pollen records and dynamic vegetation models. Spatial predictions were most reliable for steppe, forest-steppe, taiga, tundra, fens and bogs in eastern and central Europe, which had LGM climate more similar to present-day Siberia. The models for western and southern Europe, regions with a lower degree of climatic analogy, were only reliable for mires and steppe vegetation, respectively. Modelling LGM vegetation types for the wetter and warmer regions of Europe would therefore require gathering calibration data from outside Siberia. Our approach adds value to the reconstruction of vegetation at the LGM, which is limited by scarcity of pollen and macrofossil data, suggesting where specific habitats could have occurred. Despite the uncertainties of climatic extrapolations and the difficulty of validating the projections for vegetation types, the integration of palaeodistribution modelling with other approaches has a great potential for improving our understanding of biodiversity patterns during the LGM.

Impact of grazing abandonment on floristic diversity in the priority habitat type *9562 Grecian Juniper Woods

NASA Astrophysics Data System (ADS)

Vrahnakis, Michael; Kazoglou, Yannis; Fotiadis, George; Kakouros, Petros; Nasiakou, Stamatia; Soutsas, Konstantinos

2017-04-01

The habitat type *9562 Grecian juniper woods (Juniperetum excelsae) includes Greek juniper (Juniperus excelsa M. Bieb.) forests and they are found mainly in the western sector of the Prespa National Park, NW Greece. Greek juniper forests are considered extremely rare for EU-28, recommending a priority habitat type in accordance with Directive 92/43/EEC. In addition, their ecological importance is great given its high plant taxa richness; they harbor most of the 900 plant taxa found in the western sector of the Park, many of them being important for EU or global scale. The accelerated invasion of deciduous hardwoods is the most significant risk for the habitat, since its rich flora is well-adapted to open light conditions produced by the open spaced Greek junipers. Also, the dense vegetated conditions deprive the regeneration of the photophilous Greek juniper. The invasion results from the lack of its natural controller, i.e. the grazing livestock. It is estimated that the total area of juniper forests for the Devas area decreased to 89% of the area of 1945 in favor of invasive hardwoods. The paper presents the analysis of the floristic diversity of the priority habitat type *9562 Grecian Juniper Woods (Juniperetum excelsae) (GJWs). Four (4) types of juniper forest ranges (GJWs) were distinguished in terms of canopy cover: (a) pure GJWs, (b) mixed open GJWs, (c) open GJWs, and (d) mixed dense GJWs. A total of 171 plant taxa were recorded, and distributed within 43 botanical families; the largest one being Leguminosae (26 taxa). The statistically estimated plant taxa richness for pure GJWs was 116.4, for mixed open 152.6, for open 57.9, and for mixed dense 90.2 taxa. The analysis of α-diversity indices did not reveal any specific trend of diversity for the four GJWs. The behavior of the variability of diversity among the four range types of GJWs was depending on the emphasis the used indices place on properties such as taxa richness or abundance. This fact was reflected in the diversity ordering diagram, based on the Renyi's index; it was shown that the response system of the four GJWs appeared as dynamic and thus reflected the distance of a standard system and a distinct floristic diversity regime of four levels. However it seems that mixed dense GJWs had the lowest floristic diversity, while the largest had the pure and mixed open GJWs.

Vegetation cover of forest, shrub and pasture strongly influences soil bacterial community structure as revealed by 16S rRNA gene T-RFLP analysis.

PubMed

Chim Chan, On; Casper, Peter; Sha, Li Qing; Feng, Zhi Li; Fu, Yun; Yang, Xiao Dong; Ulrich, Andreas; Zou, Xiao Ming

2008-06-01

Bacterial community structure is influenced by vegetation, climate and soil chemical properties. To evaluate these influences, terminal restriction fragment length polymorphism (T-RFLP) and cloning of the 16S rRNA gene were used to analyze the soil bacterial communities in different ecosystems in southwestern China. We compared (1) broad-leaved forest, shrub and pastures in a high-plateau region, (2) three broad-leaved forests representing a climate gradient from high-plateau temperate to subtropical and tropical regions and (3) the humus and mineral soil layers of forests, shrub lands and pastures with open and restricted grazing activities, having varied soil carbon and nutrient contents. Principal component analysis of the T-RFLP patterns revealed that soil bacterial communities of the three vegetation types were distinct. The broad-leaved forests in different climates clustered together, and relatively minor differences were observed between the soil layers or the grazing regimes. Acidobacteria dominated the broad-leaved forests (comprising 62% of the total clone sequences), but exhibited lower relative abundances in the soils of shrub (31%) and pasture (23%). Betaproteobacteria was another dominant taxa of shrub land (31%), whereas Alpha- (19%) and Gammaproteobacteria (13%) and Bacteriodetes (16%) were major components of pasture. Vegetation exerted more pronounced influences than climate and soil chemical properties.

A multivariate assessment of changes in wetland habitat for waterbirds at Moosehorn National Wildlife Refuge, Maine, USA

USGS Publications Warehouse

Hierl, L.A.; Loftin, C.S.; Longcore, J.R.; McAuley, D.G.; Urban, D.L.

2007-01-01

We assessed changes in vegetative structure of 49 impoundments at Moosehorn National Wildlife Refuge (MNWR), Maine, USA, between the periods 1984-1985 to 2002 with a multivariate, adaptive approach that may be useful in a variety of wetland and other habitat management situations. We used Mahalanobis Distance (MD) analysis to classify the refuge?s wetlands as poor or good waterbird habitat based on five variables: percent emergent vegetation, percent shrub, percent open water, relative richness of vegetative types, and an interspersion juxtaposition index that measures adjacency of vegetation patches. Mahalanobis Distance is a multivariate statistic that examines whether a particular data point is an outlier or a member of a data cluster while accounting for correlations among inputs. For each wetland, we used MD analysis to quantify a distance from a reference condition defined a priori by habitat conditions measured in MNWR wetlands used by waterbirds. Twenty-five wetlands declined in quality between the two periods, whereas 23 wetlands improved. We identified specific wetland characteristics that may be modified to improve habitat conditions for waterbirds. The MD analysis seems ideal for instituting an adaptive wetland management approach because metrics can be easily added or removed, ranges of target habitat conditions can be defined by field-collected data, and the analysis can identify priorities for single or multiple management objectives.

Response of respiration and nutrient availability to drying and rewetting in soil from a semi-arid woodland depends on vegetation patch and a recent wild fire

NASA Astrophysics Data System (ADS)

Sun, Q.; Meyer, W. S.; Koerber, G.; Marschner, P.

2015-06-01

Semi-arid woodlands, which are characterised by patchy vegetation interspersed with bare, open areas, are frequently exposed to wild fire. During summer, long dry periods are occasionally interrupted by rainfall events. It is well-known that rewetting of dry soil induces a flush of respiration. However, the magnitude of the flush may differ between vegetation patches and open areas because of different organic matter content which could be further modulated by wild fire. Soils were collected from under trees, under shrubs or in open areas in unburnt and burnt sandy Mallee woodland, where part of the woodland experienced a wild fire which destroyed or damaged most of the aboveground plant parts four months before sampling. In an incubation experiment, the soils were exposed to two moisture treatments: constantly moist (CM) and drying and rewetting (DRW). In CM, soils were incubated at 80% of maximum water holding capacity for 19 days; In DRW, soils were dried for four days, kept dry for another five days, then rewet to 80% WHC and maintained at this water content until day 19. Soil respiration decreased during drying and was very low in the dry period; rewetting induced a respiration flush. Compared to soil under shrubs and in open areas, cumulative respiration per g soil in CM and DRW was greater under trees, but lower when expressed per g TOC. Organic matter content, available P, and microbial biomass C, but not available N were greater under trees than in open areas. Wild fire decreased the flush of respiration per g TOC in the open areas and under shrubs, and reduced TOC and MBC concentrations only under trees, but had little effect on available N and P concentrations. We conclude that of the impact wild fire and DRW events on nutrient cycling differ among vegetation patches of a native semiarid woodland which is related to organic matter amount and availability.

Wildlife openings

Treesearch

William M. Healy

1989-01-01

Openings provide important feeding areas for forest wildlife because herbaceous vegetation grows much more abundantly in the open than beneath a forest canopy. Herbage (grasses and forbs) is generally more nutritious and digestible than woody plant growth. Herbage is important in the diet of deer, especially in late winter and early spring. Voles and rabbits use...

Airphoto assessment of changes in aquatic vegetation

NASA Technical Reports Server (NTRS)

Markham, B. L.; Philipson, W. R.; Russel, A. E.

1977-01-01

Large scale, multiyear, color and color infrared aerial photographs were used to evaluate changes in aquatic vegetation that have accompanied a reduction in phosphorus inputs to a phosphorus-limited, eutrophic lake in New York State. The study showed that the distribution of emergent, floating and submersed vegetation could be determined with little or no concurrent ground data; that various emergent and floating types could be separated and, with limited field checks, identified; and that different submersed types are generally not separable. Major vegetative types are characterized by spectral and nonspectral features, and a classification is developed for compiling time-sequential vegetation maps.

How Tight is the Linkage Between Trees and Trout?

Treesearch

Margaret A. Wilzbach

1989-01-01

This paper explores the tightness of the linkage between stream-dwelling salmonids and ripar ian vegetation. Comparison of original distributions of salmonid species with that of vegetation types shows that distribution within a given salmonid species is not limited to a specific vegetation type, and that different salmonid species cooccur within a given vegetation...

An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

DOE PAGES

Van Berkel, Gary J.; Kertesz, Vilmos

2015-08-25

RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creatingmore » a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.« less

Assessment of Vegetation Responses and Sensitivity to the Millennium Drought in Australia

NASA Astrophysics Data System (ADS)

Jiao, T.; Williams, C. A.

2016-12-01

During the period from 1997 to 2009, Australia experienced one of the most severe and persistent drought known as the Millennium Drought (MD). Major water shortages were reported across the Australian continent as well as a great many tree mortality during and post this drought event. Given the projection of hotter and drier conditions for much of the continent, it is critical to analyze the impacts of climate extremes like MD as an indicator of possible impacts of future trends. Despite many field investigation, large-area monitoring of vegetation decline from MD remains lacking. Here, multi-source remote sensing datasets and novel methods were employed to assess the impacts of MD on vegetation in Australia in terms of the magnitude and sensitivity. Vegetation variables examined include fraction of photosynthetically absorbed radiation (fPar), vegetation optical depth (VOD) and aboveground biomass (AGB). Drought indicators are calculated based on precipitation and potential evapotranspiration from meteorological data. We found consistent spatial patterns in drought-induced declines among fPar, VOD and AGB. Common declines were observed in the east of New South Wales (NSW), the southeast of Queensland, the center and east of Victoria, and Tasmania. Severe declines (>0.2) in fPar concentrate in open forests and shrub lands while regions with more than 0.1 of decline in VOD are found widely across biome types. The net decrease in AGB could reach more than 20 Mg C per ha in the west of Victoria and the southwest of NSW. Sensitivity analysis shows that forests followed by herbaceous are more sensitive to drought than shrubs in terms of declines in fPar and VOD. In addition, vegetation tends to have larger sensitivity in semi-arid or semi-mesic regions than in areas that are either too dry or too wet.

Using Macrofossils to Reconstruct Paleoenvironmental History of Cedar Swamp, High Point NJ

NASA Astrophysics Data System (ADS)

Buhler, K. M.; Peteet, D. M.

2016-12-01

Macrofossils from deep sediment cores taken from bog environments can reveal much about the paleoclimate of a certain site. A research study conducted by Niering in 1953 focused on the pollen records from Cedar Bog that, although are able to indicate which species were present regionally, are not able to establish the specific local vegetation of the site. By identifying and counting macrofossils from the core, we can determine the species growing in Cedar Bog in High Point State Park, NJ and utilize that data to reconstruct a paleoclimatic history at the highest elevation in New Jersey. We took a 6.5m core from Cedar Bog and, from that, used 4cm³ samples taken throughout the entire depth to wash through a 250um sieve and sift through at 60x magnification, identifying the macrofossils using an extensive Lamont Doherty Earth Observatory reference collection. Additionally, we tested for the percentage of organic matter through the core using loss on ignition. We found 5 zones throughout the core depth that indicate altering habitats. Beginning with low organic matter, less than 5%, the deepest part of the core has little vegetation but high rock content. The next zone introduced Chamaecyparis thyoides in the region and a period of changing organic matter. Following this comes a domination of aquatic plants and byrozoan statoblast and, afterwards, a shift towards sedges. The top of the core shows present day vegetation types from Cedar Bog, such as sphagnum moss and Tsuga canadensis, and 96% organic matter content. The lack of vegetation and high rock content, around 6.5m deep, signal erosion that took place after deglaciation. The vegetation types in zone 2 indicate deep lake/open landscape conditions. High aquatic vegetation and bryozoan statoblasts suggest a shallow lake. The site filled in to become a fen wetland as evidenced by the abundance of Scirpus and Cladium. The final zone signifies a bog habitat represented by the domination of sphagnum and Chamaedaphne. These shifts signal an altering landscape of Cedar Bog, evolving after deglaciation from a deep lake to a shallow lake, followed by a fen wetland and eventually into a modern bog habitat. Certain vegetation and organism data indicate climatic shifts at Cedar Bog that can uncover the paleoclimate for a site located at the highest elevation in New Jersey.

Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro

PubMed Central

Rutten, Gemma; Ensslin, Andreas; Hemp, Andreas; Fischer, Markus

2015-01-01

In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866–4550m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies. PMID:26406985

Classification and description of world formation types. Part II (Description of formation types)

Treesearch

D. Faber-Langendoen; T. Keeler-Wolf; D. Meidinger; C. Josse; A. Weakley; D. Tart; G. Navarro; B. Hoagland; S. Ponomarenko; J.P. Saucier; G. Fults; E. Helmer

2012-01-01

A vegetation-ecologic classification approach has been developed in which a combination of vegetation attributes (physiognomy, structure, and floristics) and their response to ecological and biogeographic factors are used as the basis for classifying vegetation types (Faber-Langendoen et al. 2012). This approach can help support international, national and subnational...

The role of fire in deep time ecosystems

NASA Astrophysics Data System (ADS)

Scott, Andrew C.; Bond, William J.; Collinson, Margaret E.; Glasspool, Ian J.; Brown, Sarah; Braman, Dennis R.

2010-05-01

Fires are very widespread in the world today and fire has also been common in the deep past. Fire is important in structuring contemporary World vegetation maintaining extensive open vegetation where the climate has the potential to support closed forests. The influence of fire on the structure of vegetation and plant traits present in a community vary depending on the fire regime. The fire regime is the characteristic pattern of fire frequency, severity (amount of biomass removed) and spatial extent. Fire regimes depend on the synergy between external physical factors and the properties of vegetation. Changes in the fire regime can be brought about by changes in external conditions such as climate, but also by changes in vegetation such as changes in flammability or productivity that influence the amount of fuel. For example, invasion of grasses into closed wooded habitats has initiated a ‘grass fire cycle' in many parts of the world triggering cascading changes in vegetation structure and composition from forest to open grassland or savanna woodland. The spread of flammable invasive species, especially grasses, has even altered fire regimes of fire-dependent flammable communities causing catastrophic ecosystem changes. We suggest that the spread of angiosperms in the Cretaceous was promoted by the development of novel fire regimes linked to the evolution of novel, highly productive (and flammable) plants. Within the limits of physical constraints on fire occurrence, Cretaceous angiosperms would have initiated a positive feedback analogous to the grass-fire cycle rapidly accumulating fuel that promoted more frequent fires, which maintained open habitats in which rapid growth-traits of angiosperms would be most favoured promoting rapid fuel accumulation etc. Frequent fires would have altered vegetation structure and composition both by increasing mortality rates of fire-damaged trees and reducing recruitment rates of seedlings and saplings where fires recurred before juveniles had reached "fire-proof" sizes. The effect would be to create more open conditions favouring plants with the angiosperm innovations of high photosynthetic rates, rapid maturation and rapid reproduction relative to gymnosperms. Fire has some analogies to large vertebrate herbivory, particularly in the potential to open forests and create habitat for low-growing sun-loving plants over extensive areas. The role of fire in favouring low-growing ‘ruderal', plants of open habitats is similar to that proposed for dinosaurs. A switch from high-browsing dinosaurs in the Jurassic to low-browsing dinosaurs in the Cretaceous has been noted and it has been argued that the switch in browse height would favour fast-growing angiosperms. The dinosaur hypothesis has recently been tested and found wanting, for example in the timing and coincidence of angiosperm abundance and low vs. high-browsing dinosaurs. Our research of the co-occurrence of dinosaur remains and charcoal assemblages in Dinosaur Provincial Park, Alberta, has suggested that it was a dominance of gymnospermous, woody vegetation that was ravaged by fire. In addition, the co-occurrence of dinosaur remains and charcoal is significant in demonstrating that the some dinosaur bone beds may have formed as a result of extensive post-fire erosion/rapid deposition cycles. In this paper we consider the evidence for and against fire as a major factor promoting vegetation change and angiosperm spread in the Cretaceous.

Ten-year diameter and basal area growth of trees surrounding small group selection openings

Treesearch

Philip M. McDonald; Martin W. Ritchie; Celeste S. Abbott

1996-01-01

The effects of small openings in forest stands has interested silviculturists and ecologists for years. Interest generally has centered on the vegetation in the openings, not on that immediately outside of them. Quantitative information on the growth of trees adjacent to group-selection openings, although often mentioned in forestry textbooks as contributing to cost...

Vegetation Changes in the Permafrost Regions of the Qinghai-Tibetan Plateau from 1982-2012: Different Responses Related to Geographical Locations and Vegetation Types in High-Altitude Areas.

PubMed

Wang, Zhiwei; Wang, Qian; Wu, Xiaodong; Zhao, Lin; Yue, Guangyang; Nan, Zhuotong; Wang, Puchang; Yi, Shuhua; Zou, Defu; Qin, Yu; Wu, Tonghua; Shi, Jianzong

2017-01-01

The Qinghai-Tibetan Plateau (QTP) contains the largest permafrost area in a high-altitude region in the world, and the unique hydrothermal environments of the active layers in this region have an important impact on vegetation growth. Geographical locations present different climatic conditions, and in combination with the permafrost environments, these conditions comprehensively affect the local vegetation activity. Therefore, the responses of vegetation to climate change in the permafrost region of the QTP may be varied differently by geographical location and vegetation condition. In this study, using the latest Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI) product based on turning points (TPs), which were calculated using a piecewise linear model, 9 areas within the permafrost region of the QTP were selected to investigate the effect of geographical location and vegetation type on vegetation growth from 1982 to 2012. The following 4 vegetation types were observed in the 9 selected study areas: alpine swamp meadow, alpine meadow, alpine steppe and alpine desert. The research results show that, in these study areas, TPs mainly appeared in 2000 and 2001, and almost 55.1% and 35.0% of the TPs were located in 2000 and 2001. The global standardized precipitation evapotranspiration index (SPEI) and 7 meteorological variables were selected to analyze their correlations with NDVI. We found that the main correlative variables to vegetation productivity in study areas from 1982 to 2012 were precipitation, surface downward long-wave radiation and temperature. Furthermore, NDVI changes exhibited by different vegetation types within the same study area followed similar trends. The results show that regional effects rather than vegetation type had a larger impact on changes in vegetation growth in the permafrost regions of the QTP, indicating that climatic factors had a larger impact in the permafrost regions than the environmental factors (including permafrost) related to the underlying surface conditions.

Vegetation Changes in the Permafrost Regions of the Qinghai-Tibetan Plateau from 1982-2012: Different Responses Related to Geographical Locations and Vegetation Types in High-Altitude Areas

PubMed Central

Wu, Xiaodong; Zhao, Lin; Yue, Guangyang; Nan, Zhuotong; Wang, Puchang; Yi, Shuhua; Zou, Defu; Qin, Yu; Wu, Tonghua; Shi, Jianzong

2017-01-01

The Qinghai-Tibetan Plateau (QTP) contains the largest permafrost area in a high-altitude region in the world, and the unique hydrothermal environments of the active layers in this region have an important impact on vegetation growth. Geographical locations present different climatic conditions, and in combination with the permafrost environments, these conditions comprehensively affect the local vegetation activity. Therefore, the responses of vegetation to climate change in the permafrost region of the QTP may be varied differently by geographical location and vegetation condition. In this study, using the latest Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI) product based on turning points (TPs), which were calculated using a piecewise linear model, 9 areas within the permafrost region of the QTP were selected to investigate the effect of geographical location and vegetation type on vegetation growth from 1982 to 2012. The following 4 vegetation types were observed in the 9 selected study areas: alpine swamp meadow, alpine meadow, alpine steppe and alpine desert. The research results show that, in these study areas, TPs mainly appeared in 2000 and 2001, and almost 55.1% and 35.0% of the TPs were located in 2000 and 2001. The global standardized precipitation evapotranspiration index (SPEI) and 7 meteorological variables were selected to analyze their correlations with NDVI. We found that the main correlative variables to vegetation productivity in study areas from 1982 to 2012 were precipitation, surface downward long-wave radiation and temperature. Furthermore, NDVI changes exhibited by different vegetation types within the same study area followed similar trends. The results show that regional effects rather than vegetation type had a larger impact on changes in vegetation growth in the permafrost regions of the QTP, indicating that climatic factors had a larger impact in the permafrost regions than the environmental factors (including permafrost) related to the underlying surface conditions. PMID:28068392

Association between fruit, vegetable, seafood, and dairy intake and a reduction in the prevalence of type 2 diabetes in Qingdao, China.

PubMed

Liang, Jiwei; Zhang, Yanlei; Xue, Aili; Sun, Jianping; Song, Xin; Xue, Bai; Ji, Fuling; Gao, Weiguo; He, Liang; Pang, Zengchang; Qiao, Qing; Ning, Feng

2017-03-01

Fruit, vegetable, seafood, and dairy intake may reduce the risk of type 2 diabetes, but this relationship is unclear. We aimed to examine the associations between fruit, vegetable, seafood, and dairy intake and type 2 diabetes prevalence in a Chinese population. A total of 4,343 individuals aged 35-74 years participated in a population-based cross-sectional study in Qingdao, China. The frequency and quantity of fruit, vegetable, seafood, and dairy intake were determined using a standard food frequency questionnaire. Diabetes was classified according to the WHO/IDF 2006 criteria. Logistic regression analysis was employed to estimate odds ratio (OR) for type 2 diabetes in relation to fruit, vegetable, seafood, and dairy intake in a multivariable model. The multivariate-adjusted ORs (95% confidence interval) for the presence of type 2 diabetes were 0.68 (0.46-0.98), 0.50 (0.37-0.68), and 0.91 (0.66-1.25), respectively, for the highest versus the lowest groups regarding total fruit and vegetable, fruit or vegetable intake in women. The ORs for type 2 diabetes prevalence regarding the quantity of fruit and vegetable, fruit, and yogurt intake were 0.88 (0.78-0.99), 0.71 (0.61-0.82), and 0.56 (0.32-0.98) in women, but not in men. Seafood consumption was inversely associated with diabetes risk in men, but not in women; the corresponding figures were 0.58 (0.35-0.96) and 0.92 (0.63-1.36), respectively. Fruit, vegetable, and yogurt intake in women and seafood intake in men were inversely associated with type 2 diabetes prevalence in this Chinese population. These findings require confirmation in a prospective study.

What are the most important factors determining different vegetation types in the Chapada Diamantina, Brazil?

PubMed

Neves, S P S; Funch, R; Conceição, A A; Miranda, L A P; Funch, L S

2016-06-01

A transect was used to examine the environmental and biological descriptors of a compact vegetation mosaic in the Chapada Diamantina in northeastern Brazil, including the floristic composition, spectrum of plant life forms, rainfall, and soil properties that defined areas of cerrado (Brazilian savanna), caatinga (seasonally dry tropical forest thorny, deciduous shrub/arboreal vegetation) and cerrado-caatinga transition vegetation. The floristic survey was made monthly from April/2009 to March/2012. A dendrogram of similarity was generated using the Jaccard Index based on a matrix of the species that occurred in at least two of the vegetation types examined. The proportions of life forms in each vegetation type were compared using the chi-square test. Composite soil samples were analyzed by simple variance (ANOVA) to examine relationships between soil parameters of each vegetation type and the transition area. The monthly precipitation levels in each vegetation type were measured and compared using the chi-square test. A total of 323 species of angiosperms were collected distributed in 193 genera and 54 families. The dendrogram demonstrated strong difference between the floristic compositions of the cerrado and caatinga, sharing 2% similarity. The chi-square test did not demonstrate any significant statistical differences between the monthly values of recorded rainfall. The organic matter and clay contents of the soilsin the caatinga increased while sand decreased, and the proportions of therophyte, hemicryptophyte, and chamaephyte life forms decreased and phanerophytes increased. We can therefore conclude that the floristic composition and the spectrum of life forms combined to define the cerrado and caatinga vegetation along the transect examined, with soil being the principal conditioning factor determining the different vegetation types, independent of precipitation levels.

Experimental trampling of vegetation. II. Predictors of resistance and resilience

Treesearch

David N. Cole

1995-01-01

1. Experimental trampling was conducted in 18 vegetation types in five separate mountain regions in the United States. Each type was trampled 0-500 times and vegetation response was assessed 2 weeks and 1 year after trampling. 2. The response of vegetation to trampling is expressed in terms of three indices: resistance, tolerance and resilience. Resistance...

Predicting the effect of fire on large-scale vegetation patterns in North America.

Treesearch

Donald McKenzie; David L. Peterson; Ernesto. Alvarado

1996-01-01

Changes in fire regimes are expected across North America in response to anticipated global climatic changes. Potential changes in large-scale vegetation patterns are predicted as a result of altered fire frequencies. A new vegetation classification was developed by condensing Kuchler potential natural vegetation types into aggregated types that are relatively...

Arctic Tundra Vegetation Functional Types Based on Photosynthetic Physiology and Optical Properties

NASA Technical Reports Server (NTRS)

Huemmrich, Karl Fred; Gamon, John A.; Tweedie, Craig E.; Campbell, Petya K. Entcheva; Landis, David R.; Middleton, Elizabeth M.

2013-01-01

Non-vascular plants (lichens and mosses) are significant components of tundra landscapes and may respond to climate change differently from vascular plants affecting ecosystem carbon balance. Remote sensing provides critical tools for monitoring plant cover types, as optical signals provide a way to scale from plot measurements to regional estimates of biophysical properties, for which spatial-temporal patterns may be analyzed. Gas exchange measurements were collected for pure patches of key vegetation functional types (lichens, mosses, and vascular plants) in sedge tundra at Barrow, AK. These functional types were found to have three significantly different values of light use efficiency (LUE) with values of 0.013 plus or minus 0.0002, 0.0018 plus or minus 0.0002, and 0.0012 plus or minus 0.0001 mol C mol (exp -1) absorbed quanta for vascular plants, mosses and lichens, respectively. Discriminant analysis of the spectra reflectance of these patches identified five spectral bands that separated each of these vegetation functional types as well as nongreen material (bare soil, standing water, and dead leaves). These results were tested along a 100 m transect where midsummer spectral reflectance and vegetation coverage were measured at one meter intervals. Along the transect, area-averaged canopy LUE estimated from coverage fractions of the three functional types varied widely, even over short distances. The patch-level statistical discriminant functions applied to in situ hyperspectral reflectance data collected along the transect successfully unmixed cover fractions of the vegetation functional types. The unmixing functions, developed from the transect data, were applied to 30 m spatial resolution Earth Observing-1 Hyperion imaging spectrometer data to examine variability in distribution of the vegetation functional types for an area near Barrow, AK. Spatial variability of LUE was derived from the observed functional type distributions. Across this landscape, a fivefold variation in tundra LUE was observed. LUE calculated from the functional type cover fractions was also correlated to a spectral vegetation index developed to detect vegetation chlorophyll content. The concurrence of these alternate methods suggest that hyperspectral remote sensing can distinguish functionally distinct vegetation types and can be used to develop regional estimates of photosynthetic LUE in tundra landscapes.

Wildlife and Wildlife Habitat Loss Assessment at Green Peter-Foster Project; Middle Fork Santiam River, Oregon, 1985 Final Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noyes, J.H.

1986-02-01

A habitat based assessment was conducted of the US Army Corps of Engineers' Green Peter-Foster Dam and Reservoir Project on the Middle Fork Santiam River, Oregon, to determine losses or gains resulting from the development and operation of the hydroelectric related components of the project. Preconstruction, postconstruction, and recent vegetation cover types at the project site were mapped based on aerial photographs from 1955, 1972, and 1979, respectively. Vegetation cover types were identified within the affected area and acreages of each type at each period were determined. Eleven wildlife target species were selected to represent a cross-section of species groupsmore » affected by the project. An interagency team evaluated the suitability of the habitat to support the target species at each time period. An evaluation procedure which accounted for both the quantity and quality of habitat was used to aid in assessing impacts resulting from the project. The Green Peter-Foster Project extensively altered or affected 7873 acres of land and river in the Santiam River drainage. Impacts to wildlife centered around the loss of 1429 acres of grass-forb vegetation, 768 acres of shrubland, and 717 acres of open conifer forest cover types. Impacts resulting from the Green Peter-Foster Project included the loss of critical winter range for black-tailed deer and Roosevelt elk, and the loss of year-round habitat for deer, upland game birds, river otter, beaver, pileated woodpecker, and many other wildlife species. Bald eagle and osprey were benefited by an increase in foraging habitat. The potential of the affected area to support wildlife was greatly altered as a result of the Green Peter-Foster Project. Losses or gains in the potential of the habitat to support wildlife will exist over the life of the project.« less

Arctic Tundra Vegetation Functional Types Based on Photosynthetic Physiology and Optical Properties

NASA Technical Reports Server (NTRS)

Huemmrich, Karl F.; Gamon, John; Tweedie, Craig; Campbell, Petya P. K.; Landis, David; Middleton, Elizabeth

2012-01-01

Climate change in tundra regions may alter vegetation species composition and ecosystem carbon balance. Remote sensing provides critical tools for monitoring these changes as optical signals provide a way to scale from plot measurements to regional patterns. Gas exchange measurements of pure patches of key vegetation functional types (lichens, mosses, and vascular plants) in sedge tundra at Barrow AK, show three significantly different values of light use efficiency (LUE) with values of 0.013+/-0.001, 0.0018+/-0.0002, and 0.0012 0.0001 mol C/mol absorbed quanta for vascular plants, mosses and lichens, respectively. Further, discriminant analysis of patch reflectance identifies five spectral bands that can separate each vegetation functional type as well as nongreen material (bare soil, standing water, and dead leaves). These results were tested along a 100 m transect where midsummer spectral reflectance and vegetation coverage were measured at one meter intervals. Area-averaged canopy LUE estimated from coverage fractions of the three functional types varied widely, even over short distances. Patch-level statistical discriminant functions applied to in situ hyperspectral reflectance successfully unmixed cover fractions of the vegetation functional types. These functions, developed from the tram data, were applied to 30 m spatial resolution Earth Observing-1 Hyperion imaging spectrometer data to examine regional variability in distribution of the vegetation functional types and from those distributions, the variability of LUE. Across the landscape, there was a fivefold variation in tundra LUE that was correlated to a spectral vegetation index developed to detect vegetation chlorophyll content.

Relationships between forest cutting and understory vegetation: an overview of eastern hardwood stands

Treesearch

Hewlette S. Crawford

1976-01-01

The impacts of forest cutting upon understory vegetation were evaluated for Ozark oak-hickory and Appalachian oak-pine stands. These findings were related to similar information from other eastern forest types. Production of understory vegetation is related to stand type, stand structure, stand disturbance, and site. Stand type, structure, and site operate together to...

[Pollen analysis of the post-emergence residue of Centris tarsata Smith (Hymenoptera: Apidae, Centridini) nests].

PubMed

Dórea, Marcos da C; Dos Santos, Francisco de A R; Lima, Luciene C de L E; Figueroa, Luís E R

2009-01-01

A new treatment protocol was developed to analyze pollen residues found in nests of Centris tarsata Smith harvested from nest-traps. The study area was located in the Canudos Biological Station in the municipality of Canudos (09 masculine56'34'S; 38 masculine59'17'W), in the northeastern micro-region of Bahia State, Brazil. The local vegetation is an open caatinga (deciduous dryland vegetation), the regional climate is semi-arid, the average annual temperature is 24.1 masculineC, and the annual regional rainfall rate is 454 mm. Ten nests of C. tarsata were collected in trap-nests during the first semester of 2004. Pollen analysis from the nests required the development of a new methodology that combined techniques of palynological sediment analysis with the more common pollinic analysis by acetolysis. Microscopic analyses employed optical microscopy techniques. The pollinic spectrum of the samples from C. tarsata indicated the presence of 17 pollen types from seven plant families, which were present in assemblage of five to eleven pollen types, pointed to the plants used by bees to feed on their offspring. The most represented plant families were Leguminosae (49.3%) and Solanaceae (43.2%). The most frequent pollen types in the samples were from Solanum paniculatum (43.8%) and Senna rizzini (32.1%). The protocol developed provides a new tool for diet assessment of Centris and other groups of solitary bees.

Retrieval of seasonal dynamics of forest understory reflectance from semiarid to boreal forests using MODIS BRDF data

NASA Astrophysics Data System (ADS)

Pisek, Jan; Chen, Jing M.; Kobayashi, Hideki; Rautiainen, Miina; Schaepman, Michael E.; Karnieli, Arnon; Sprinstin, Michael; Ryu, Youngryel; Nikopensius, Maris; Raabe, Kairi

2016-03-01

Spatial and temporal patterns of forest background (understory) reflectance are crucial for retrieving biophysical parameters of forest canopies (overstory) and subsequently for ecosystem modeling. In this communication, we retrieved seasonal courses of understory normalized difference vegetation index (NDVI) from multiangular Moderate Resolution Imaging Spectroradiometer bidirectional reflectance distribution function (MODIS BRDF)/albedo data. We compared satellite-based seasonal courses of understory NDVI to understory NDVI values measured in different types of forests distributed along a wide latitudinal gradient (65.12°N-31.35°N). Our results indicated that the retrieval method performs well particularly over open forests of different types. We also demonstrated the limitations of the method for closed canopies, where the understory signal retrieval is much attenuated.

Low-cost grass restoration using erosion barriers in a degraded African rangeland

USGS Publications Warehouse

Kimiti, David W; Riginos, Corinna; Belnap, Jayne

2017-01-01

Rangeland degradation, typified by extensive bare ground and soil erosion, is a serious problem around the world. In sub-Saharan Africa, rangeland degradation threatens the food security of millions of people who depend on livestock and the region's large mammalian wildlife diversity. We tested the ability of five simple, low-cost erosion barriers to promote grass and forb establishment in a bare ground-dominated rangeland in Kenya. These treatments were: (1) trenches with small berms; (2) bundles of branches; and bundles of branches with (3) elephant dung balls, (4) burlap sacking, or (5) nylon mesh sacking inside them. We also tested whether barrier performance depended on (1) supplemental seeding with the grass Cenchrus ciliaris and (2) whether a barrier was located next to existing vegetation patches versus in the open. Within months, the trench and nylon mesh barriers had accumulated 20–50% more sediment than other treatments and had greater grass and forb seedling establishment. Seeding with Cenchrusresulted in higher herbaceous cover but was not necessary for other grasses to establish. After 3 years, the trench and nylon mesh barriers had created patches of new vegetation averaging 18–63% larger than patches created by the other treatments. Barriers that were initially adjacent to existing vegetation had created new vegetation patches averaging 65% larger than those created by solitary barriers. Results suggest that all barrier types increase grass cover but that trenches—especially if placed next to existing vegetation patches—are a particularly cost-effective way to reduce bare ground and erosion in degraded rangelands.

Evidence of climatic effects on soil, vegetation and landform in temperate forests of south-eastern Australia

NASA Astrophysics Data System (ADS)

Inbar, Assaf; Nyman, Petter; Lane, Patrick; Sheridan, Gary

2016-04-01

Water and radiation are unevenly distributed across the landscape due to variations in topography, which in turn causes water availability differences on the terrain according to elevation and aspect orientation. These differences in water availability can cause differential distribution of vegetation types and indirectly influence the development of soil and even landform, as expressed in hillslope asymmetry. While most of the research on the effects of climate on the vegetation and soil development and landscape evolution has been concentrated in drier semi-arid areas, temperate forested areas has been poorly studied, particularly in South Eastern Australia. This study uses soil profile descriptions and data on soil depth and landform across climatic gradients to explore the degrees to which coevolution of vegetation, soils and landform are controlled by radiative forcing and rainfall. Soil depth measurements were made on polar and equatorial facing hillslopes located at 3 sites along a climatic gradient (mean annual rainfall between 700 - 1800 mm yr-1) in the Victorian Highlands, where forest types range from dry open woodland to closed temperate rainforest. Profile descriptions were taken from soil pits dag on planar hillslopes (50 m from ridge), and samples were taken from each horizon for physical and chemical properties analysis. Hillslope asymmetry in different precipitation regimes of the study region was quantified from Digital Elevation Models (DEMs). Significant vegetation differences between aspects were noted in lower and intermediate rainfall sites, where polar facing aspects expressed higher overall biomass than the drier equatorial slope. Within the study domain, soil depth was strongly correlated with forest type and above ground biomass. Soil depths and chemical properties varied between topographic aspects and along the precipitation gradient, where wetter conditions facilitate deeper and more weathered soils. Furthermore, soil depths showed different patterns as a function of contributing area. While soils on the polar facing slope became deeper, soils on the equatorial facing slope kept a uniform depth with increasing contributing area, pointing to different governing geomorphic processes at work. Using slope-area relationships analysis, polar facing slopes were found to be generally steeper and with longer distance to channel initiation point (if existent) than that of the equatorial facing slopes, strengthening the evidence of climate-affected differential geomorphic processes shaping the hillslope form. The results point out to the effect of climate on the development and coevolution of soil, vegetation and landform in the temperate part of Australia.

EMISSIONS FROM THE BURNING OF VEGETATIVE DEBRIS IN AIR CURTAIN DESTRUCTORS

EPA Science Inventory

Although no data has been published on emissions from construction and demolition (C&D) debris burned in an air curtain destructor (ACD), a few studies provide information on emissions from combustion of vegetative debris. These results are compared to studies of open burning of...

The feasibility of using a universal Random Forest model to map tree height across different locations and vegetation types

NASA Astrophysics Data System (ADS)

Su, Y.; Guo, Q.; Jin, S.; Gao, S.; Hu, T.; Liu, J.; Xue, B. L.

2017-12-01

Tree height is an important forest structure parameter for understanding forest ecosystem and improving the accuracy of global carbon stock quantification. Light detection and ranging (LiDAR) can provide accurate tree height measurements, but its use in large-scale tree height mapping is limited by the spatial availability. Random Forest (RF) has been one of the most commonly used algorithms for mapping large-scale tree height through the fusion of LiDAR and other remotely sensed datasets. However, how the variances in vegetation types, geolocations and spatial scales of different study sites influence the RF results is still a question that needs to be addressed. In this study, we selected 16 study sites across four vegetation types in United States (U.S.) fully covered by airborne LiDAR data, and the area of each site was 100 km2. The LiDAR-derived canopy height models (CHMs) were used as the ground truth to train the RF algorithm to predict canopy height from other remotely sensed variables, such as Landsat TM imagery, terrain information and climate surfaces. To address the abovementioned question, 22 models were run under different combinations of vegetation types, geolocations and spatial scales. The results show that the RF model trained at one specific location or vegetation type cannot be used to predict tree height in other locations or vegetation types. However, by training the RF model using samples from all locations and vegetation types, a universal model can be achieved for predicting canopy height across different locations and vegetation types. Moreover, the number of training samples and the targeted spatial resolution of the canopy height product have noticeable influence on the RF prediction accuracy.

Table of Phenylalanine Content of Foods: Comparative Analysis of Data Compiled in Food Composition Tables.

PubMed

Araújo, Ana Claudia Marquim F; Araújo, Wilma M C; Marquez, Ursula M Lanfer; Akutsu, Rita; Nakano, Eduardo Y

2017-01-01

Knowing the phenylalanine (Phe) content of foods is essential for managing the diet of patients with phenylketonuria. Data on the Phe content of foods are scarce and sometimes vary between different Food Composition Tables (FCT). Brazil created its own table of the Phe contents of fruits and vegetables based exclusively on the chemical analysis of protein content, considering that proteins contain 3-4% Phe (TCFA/ANVISA). This study compared the protein and Phe contents of vegetables and fruits provided by the TCFA/ANVISA with those listed in international food composition tables. The Phe content of 71 fruits and vegetables listed in TCFA/ANVISA was classified into four subgroups, and the Wilcoxon nonparametric test compared the Phe and mean protein contents provided by the FCTs. All tests considered the bilateral hypothesis, and the level of significance was set at 5%. The Spearman's correlation coefficient measured the statistical dependence between Phe and protein contents. The mean Phe content was <50 mg Phe/100 g for 15 fruits; >50 mg/100 g for 11 type-A vegetables; <50 mg/100 g for 8 type-B vegetables; ≤50 mg/100 g for 7 type-C vegetables. The percentage of Phe in protein varied from 3.13 ± 1.03% to 3.74 ± 2.55% in fruits; 3.33 ± 1.41 to 4.82 ± 1.17 in type-A vegetables; 3.46 ± 1.25% to 4.83 ± 2.46 in type-B vegetables; and 3.14% ± 1.49 to 4.62% ± 2.26 in type-C vegetables. The Phe and protein contents provided by most FCTs were positively correlated, suggesting that it is possible to estimate the Phe content of fruits by multiplying its protein content by 3%. For type-A, -B, and -C vegetables, 4% may be used.

Response of bird species densities to habitat structure and fire history along a Midwestern open-forest gradient

USGS Publications Warehouse

Grundel, R.; Pavlovic, N.B.

2007-01-01

Oak savannas were historically common but are currently rare in the Midwestern United States. We assessed possible associations of bird species with savannas and other threatened habitats in the region by relating fire frequency and vegetation characteristics to seasonal densities of 72 bird species distributed across an open-forest gradient in northwestern Indiana. About one-third of the species did not exhibit statistically significant relationships with any combination of seven vegetation characteristics that included vegetation cover in five vertical strata, dead tree density, and tree height. For 40% of the remaining species, models best predicting species density incorporated tree density. Therefore, management based solely on manipulating tree density may not be an adequate strategy for managing bird populations along this open-forest gradient. Few species exhibited sharp peaks in predicted density under habitat conditions expected in restored savannas, suggesting that few savanna specialists occur among Midwestern bird species. When fire frequency, measured over fifteen years, was added to vegetation characteristics as a predictor of species density, it was incorporated into models for about one-quarter of species, suggesting that fire may modify habitat characteristics in ways that are important for birds but not captured by the structural habitat variables measured. Among those species, similar numbers had peaks in predicted density at low, intermediate, or high fire frequency. For species suggested by previous studies to have a preference for oak savannas along the open-forest gradient, estimated density was maximized at an average fire return interval of about one fire every three years. ?? The Cooper Ornithological Society 2007.

Rapid Characterisation of Vegetation Structure to Predict Refugia and Climate Change Impacts across a Global Biodiversity Hotspot

PubMed Central

Schut, Antonius G. T.; Wardell-Johnson, Grant W.; Yates, Colin J.; Keppel, Gunnar; Baran, Ireneusz; Franklin, Steven E.; Hopper, Stephen D.; Van Niel, Kimberley P.; Mucina, Ladislav; Byrne, Margaret

2014-01-01

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR) data and Red Green and Blue (RGB) imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region. Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8) and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R2 of 0.8–0.9) allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented enables the integration of site-based biotic assessment with structural vegetation types for the rapid delineation and prioritization of key refugia. PMID:24416149

Rapid characterisation of vegetation structure to predict refugia and climate change impacts across a global biodiversity hotspot.

PubMed

Schut, Antonius G T; Wardell-Johnson, Grant W; Yates, Colin J; Keppel, Gunnar; Baran, Ireneusz; Franklin, Steven E; Hopper, Stephen D; Van Niel, Kimberley P; Mucina, Ladislav; Byrne, Margaret

2014-01-01

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR) data and Red Green and Blue (RGB) imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region. Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8) and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R(2) of 0.8-0.9) allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented enables the integration of site-based biotic assessment with structural vegetation types for the rapid delineation and prioritization of key refugia.

AmeriFlux US-Oho Oak Openings

DOE Data Explorer

Chen, Jiquan [University of Toledo / Michigan State University

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-Oho Oak Openings. Site Description - The Ohio Oak Openings site is located within the Oak Openings Preserve Metropark of northwest Ohio, one of the few remaining oak woodlands/savanna/prairie complexes in the Midwest. Declared one of the "One of America's Last Great Places" by the Nature Conservancy the area consists of four main vegetation types: Oak Woodlands, Oak Savanna, Floodplain Forests and Wet Prairies. The stand surrounding the tower is mainly Oak Woodlands dominated by red, white and black oaks with a relatively abundant population of red maples indicating high soil moisture retention and a history of limited fire disturbances. Most of the area was cleared for agriculture at the time of Euro-American settlements in the mid to late-19th century. A large fraction of the cleared land was later abandoned due to the poor sandy soils. These areas reverted to Oak Savannas and in cases where fire was limited progressively made the transition to Oak Woodlands. Today patches of the forest are burned every few years as part of prescribed burning cycle to control stand density.

Impact on Dietary Choices after Discount Supermarket Opens in Low-Income Community.

PubMed

Jilcott Pitts, Stephanie Bell; Wu, Qiang; McGuirt, Jared T; Sharpe, Patricia A; Rafferty, Ann P

2018-04-11

To examine (1) the association of a new supermarket opening with dietary intake and perceptions of healthy food availability, and (2) associations of distance to the primary food store and mean prices of fruits, vegetables, and sugary beverages with levels of consumption of these foods and body mass index in a low-income, southeastern community. The researchers used cross-sectional, self-administered questionnaire data and supermarket audit data collected in the supermarket community and comparison community before (2015) and after (2016) the supermarket opening. A difference-in-difference analysis employed propensity scores to compare pretest and posttest differences between communities. There were no significant differences between communities on dietary behaviors. There was a significant cross-sectional, inverse association between distance to the primary food store and fruit and vegetable consumption among all respondents in 2016. The results suggest that adding a new discount supermarket is not necessarily associated with improvements in residents' fruit, vegetable, or sugary beverage consumption, or in their perceptions of the availability of healthy food in the neighborhood. However, distance to the store may be important. Copyright © 2018. Published by Elsevier Inc.

Vegetation stability in the Southeastern Brazilian coastal area from 5500 to 1400 14C yr BP deduced from charcoal analysis.

PubMed

Scheel-Ybert

2000-06-01

Charcoal analysis of six shell mounds showed that no major changes of the mainland vegetation ecosystem have taken place along the southeastern Brazilian coast (22 degrees 53'-22 degrees 57'S, 42 degrees 03'-42 degrees 33'W) from 5500 to 1400 14C yr BP. These shell mounds have been occupied by sedentary fisher-gatherer-hunters. Charcoal fragments retrieved from vertical profiles in the archaeological sites were examined; taxonomic determinations were based on a reference collection of charred woods and a program for computer-aided identification. Charcoal assemblages of all the studied sites present taxa from various restinga vegetation types, mangroves, xeromorphic coastal forest, and inland Atlantic Forest. The restinga ecosystem, characteristic of the Brazilian coast, is associated with sandy beach ridges; the restinga forest was much more abundant during the studied period than nowadays. The charcoal assemblages represent mainly the local vegetation; a regional reconstruction depends on the study of numerous sites. In the Cabo Frio region, open restinga taxa are more abundant in the Sambaqui do Forte, while forest elements are more important in the Sambaquis Salinas Peroano and Boca da Barra. The sites studied in the Arraial do Cabo (Sambaqui da Ponta da Cabeça) and in the Saquarema regions (Sambaquis da Pontinha and da Beirada) show that open restinga formations were locally predominant. A comparison of multivariate analysis applied to both charcoal assemblages and to phytosociological data of the extant vegetation showed a good correspondence between the charcoal spectra and the present vegetation. The high taxonomic diversity of archaeological charcoal samples and numerous fragments showing traces of decay before charring suggests that aleatory gathering of dead wood constituted the main source of firewood for fisher-gatherer-hunters populations. Condalia sp. was probably selected for cultural reasons.The only significant fluctuations on the charcoal spectra relate to the mangrove vegetation. Two relatively humid episodes (recorded from ca. 5500 to 4900/4500 and from ca. 2300 to 2000 14C yr BP), intercalated by two episodes of increased dryness with increased lagoon salinity (from ca. 4900/4500 to 2300 and from ca. 2000 to 1400 14C yr BP) were recorded in the Cabo Frio region. The changes in mangrove vegetation cannot be attributed to sea-level variations, for the three regressive and the two transgressive episodes identified for the Brazilian coast during this period are not in phase with the development of mangroves. The stability of the mainland vegetation ecosystem is probably due to the edaphic character of the coastal environments, which makes coastal formations much more resistant to climatic variations and less sensitive to climatic change. We propose that this environmental stability was a decisive factor in the maintenance of the fisher-gatherer-hunter sociocultural system.

Vegetation disturbance and maintenance of diversity in intermittently flooded Carolina Bays in South Carolina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirkman, L.K.; Sharitz, R.R.

1994-02-01

The authors manipulated the fire regime and soil disturbance in four grass-dominated Carolina bay wetlands during a prolonged drought period and examined vegetation composition and cover within dominant vegetation types prior to and after treatments. The authors used the seedling emergence technique to determine the role of the seed bank in the recovery process. Burning did not affect richness, evenness, or diversity (all vegetation types combined); however, soil tillage increased diversity, including both evenness and richness. Percent similarity of the vegetation before and after disturbance was greater in the burning treatment than in the tillage treatment, probably due to greatermore » disruption of the rhizomes of the perennial vegetation by tillage. Vegetation types varied in degree of recovery, although dominance was not altered by either treatment. Several native fugitive species increased following disturbance, indicating that species coexistence in these Carolina bay wetlands depends on the life history characteristics of residual vegetation, as well as that of seed bank species.« less

Stalking Antibiotic-Resistant Bacteria in Common Vegetables

ERIC Educational Resources Information Center

Brock, David; Boeke, Caroline; Josowitz, Rebecca; Loya, Katherine

2004-01-01

The study developed a simple experimental protocol for studying antibiotic resistant bacteria that will allow students to determine the proportion of such bacteria found on common fruit and vegetable crops. This protocol can open up the world of environmental science and show how human behavior can dramatically alter ecosystems.

Accumulation and health risk of heavy metals in vegetables from harmless and organic vegetable production systems of China.

PubMed

Chen, Yong; Hu, Wenyou; Huang, Biao; Weindorf, David C; Rajan, Nithya; Liu, Xiaoxiao; Niedermann, Silvana

2013-12-01

Heavy metal accumulation in vegetables is a growing concern for public health. Limited studies have elucidated the heavy metal accumulation characteristics and health risk of different vegetables produced in different facilities such as greenhouses and open-air fields and under different management modes such as harmless and organic. Given the concern over the aforementioned factors related to heavy metal accumulation, this study selected four typical greenhouse vegetable production bases, short-term harmless greenhouse vegetable base (SHGVB), middle-term harmless greenhouse vegetable base (MHGVB), long-term harmless greenhouse vegetable base (LHGVB), and organic greenhouse vegetable base (OGVB), in Nanjing City, China to study heavy metal accumulation in different vegetables and their associated health risks. Results showed that soils and vegetables from SHGVB and OGVB apparently accumulated fewer certain heavy metals than those from other bases, probably due to fewer planting years and special management, respectively. Greenhouse conditions significantly increased certain soil heavy metal concentrations relative to open-air conditions. However, greenhouse conditions did not significantly increase concentrations of As, Cd, Cu, Hg, and Zn in leaf vegetables. In fact, under greenhouse conditions, Pb accumulation was effectively reduced. The main source of soil heavy metals was the application of large amounts of low-grade fertilizer. There was larger health risk for producers' children to consume vegetables from the three harmless vegetable bases than those of residents' children. The hazard index (HI) over a large area exceeded 1 for these two kinds of children in the MHGVB and LHGVB. There was also a slight risk in the SHGVB for producers' children solely. However, the HI of the whole area of the OGVB for two kinds of children was below 1, suggesting low risk of heavy metal exposure through the food chain. Notably, the contribution rate of Cu and Zn to the HI were high in the four bases, yet current Chinese standards provide no limit for the concentrations of Cu and Zn; thus a potential health risk concerning these metals exists. © 2013 Elsevier Inc. All rights reserved.

40 CFR 412.4 - Best management practices (BMPs) for land application of manure, litter, and process wastewater.

Code of Federal Regulations, 2012 CFR

2012-07-01

...: Open tile line intake structures, sinkholes, and agricultural well heads. (2) Vegetated buffer means a... surface waters, open tile line intake structures, sinkholes, agricultural well heads, or other conduits to...

40 CFR 412.4 - Best management practices (BMPs) for land application of manure, litter, and process wastewater.

Code of Federal Regulations, 2013 CFR

2013-07-01

...: Open tile line intake structures, sinkholes, and agricultural well heads. (2) Vegetated buffer means a... surface waters, open tile line intake structures, sinkholes, agricultural well heads, or other conduits to...

40 CFR 412.4 - Best management practices (BMPs) for land application of manure, litter, and process wastewater.

Code of Federal Regulations, 2014 CFR

2014-07-01

...: Open tile line intake structures, sinkholes, and agricultural well heads. (2) Vegetated buffer means a... surface waters, open tile line intake structures, sinkholes, agricultural well heads, or other conduits to...

The response of vegetation dynamics of the different alpine grassland types to temperature and precipitation on the Tibetan Plateau.

PubMed

Sun, Jian; Qin, Xiaojing; Yang, Jun

2016-01-01

The spatiotemporal variability of the Normalized Difference Vegetation Index (NDVI) of three vegetation types (alpine steppe, alpine meadow, and alpine desert steppe) across the Tibetan Plateau was analyzed from 1982 to 2013. In addition, the annual mean temperature (MAT) and annual mean precipitation (MAP) trends were quantified to define the spatiotemporal climate patterns. Meanwhile, the relationships between climate factors and NDVI were analyzed in order to understand the impact of climate change on vegetation dynamics. The results indicate that the maximum of NDVI increased by 0.3 and 0.2 % per 10 years in the entire regions of alpine steppe and alpine meadow, respectively. However, no significant change in the NDVI of the alpine desert steppe has been observed since 1982. A negative relationship between NDVI and MAT was found in all these alpine grassland types, while MAP positively impacted the vegetation dynamics of all grasslands. Also, the effects of temperature and precipitation on different vegetation types differed, and the correlation coefficient for MAP and NDVI in alpine meadow is larger than that for other vegetation types. We also explored the percentages of precipitation and temperature influence on NDVI variation, using redundancy analysis at the observation point scale. The results show that precipitation is a primary limiting factor for alpine vegetation dynamic, rather than temperature. Most importantly, the results can serve as a tool for grassland ecosystem management.

Vegetation Impacts on Near Bank Flows

NASA Astrophysics Data System (ADS)

Hopkinson, L. C.; Wynn, T. M.

2008-12-01

Sediment, a leading cause of water quality impairment, damages aquatic ecosystems and interferes with recreational uses and water treatment processes. A significant sediment source to streams, streambank retreat, has largely been ignored. Vegetation is an important component of stream restoration designs used to control streambank retreat, but vegetation effects on near bank flows need to be quantified. The goal of this research is to evaluate the effects of streambank vegetation on near bank flows and boundary shear stress. A flume experiment was conducted comparing three distinct streambank vegetation types: trees, shrubs, and grass. A second order prototype stream (Tom's Creek in Blacksburg, VA), with individual reaches dominated by the vegetation treatments was modeled using a fixed-bed Froude-scale modeling technique. One model streambank of the prototype stream was constructed for each vegetation type and compared to a bare control (only grain roughness). Simulated vegetation (e.g. woven grass mat and wooden dowels) was attached in locations identified in a field survey. Velocity profiles perpendicular to the flume model boundary will be evaluated along five cross sections for each vegetation treatment. Reynolds, law of the wall, and turbulent kinetic energy shear stresses will be analyzed using velocity measurements made with a three-dimensional acoustic Doppler velocimeter (ADV). Velocity profiles perpendicular to the flume model streambank will also be evaluated. The velocity profiles will be compared among vegetation types to see if profiles are similar along the bank face. This research is intended to improve our understanding of the role of riparian vegetation in stream morphology by evaluating the effects of vegetation on boundary shear stress, providing insight to the type and density of vegetation required for streambank stability. The results will also aide in quantifying sediment inputs from streambanks, providing quantitative information for stream restoration projects and watershed management planning.

Inventory and monitoring of natural vegetation and related resources in an arid environment

NASA Technical Reports Server (NTRS)

Schrumpf, B. J. (Principal Investigator); Johnson, J. R.; Mouat, D. A.

1973-01-01

The author has identified the following significant results. A vegetation classification has been established for the test site (approx. 8300 sq km); 31 types are recognized. Some relationships existing among vegetation types and associated terrain features have been characterized. Terrain features can be used to discriminate vegetation types. Macrorelief interpretations on ERTS-1 imagery can be performed with greater accuracy when using high sun angle stereoscopic viewing rather than low sun angle monoscopic viewing. Some plant phenological changes are being recorded by the MSS system.

Assessment of the environmental effects of mining using SPOT-Vegetation NDVI

NASA Astrophysics Data System (ADS)

Tote, C.; Swinnen, E.; Goossens, M.; Reusen, I.; Delalieux, S.

2012-04-01

Within the ImpactMin project, funded by the Framework Programme 7 of the European Commission, new methods for the environmental impact monitoring of mining operations are being developed. The objective of this study is to analyze the impact of mining on soil properties through assessment of the vegetation status using time series analysis of low resolution Normalized Difference Vegetation Index (NDVI) images derived from SPOT-Vegetation. The study focuses on the surroundings of mining areas in the Orenburg region in the Russian Urals. Karabash has been a centre for mining and metal production for well over 3000 years, and environmental impact of (historical) mining in the area is extremely severe. The area was characterized as an 'ecological disaster zone', based on chemical analysis of soil samples in the area [1]. The mining activities were intensified in the early to mid-20th century, but the old smelter was modernized in the 1990s. A time series of 10-daily NDVI images from SPOT-Vegetation (S10 April/1998-December/2010 at 1km2 resolution, http://www.vgt.vito.be/) is analyzed. Different land cover types clearly show different phenology. To remove seasonal vegetation changes and thus to facilitate the interpretation through the historical record, a Standardized Difference Vegetation Index (SDVI) was calculated for each pixel and for each record of the time series. The first results of trend analyses indicate a strong recovery of open forests in the Karabash region in the last decade. To what extent this can be related to reduced mining impact or climate factors, still needs to be assessed. Further research will also focus on the spatial heterogeneity of phenological parameters, in relation to distance to and wind direction of the smelters and soil properties. [1] V. Nestersnko, "Urban associations of elements- environmental pollutants in Karabash city (Chelyabinsk oblast) as a reflection of ore-chemical descriptions of mineral raw material", Proceedings of the Chelyabinsk Scientific Center, vol. 3, pp. 58-62, 2006.

7300 years of vegetation history and climate for NW Malta: a Holocene perspective

NASA Astrophysics Data System (ADS)

Gambin, B.; Andrieu-Ponel, V.; Médail, F.; Marriner, N.; Peyron, O.; Montade, V.; Gambin, T.; Morhange, C.; Belkacem, D.; Djamali, M.

2015-09-01

This paper investigates the Holocene vegetation dynamics for Burmarrad in north-west Malta and provides a pollen-based quantitative palaeoclimatic reconstruction for this centrally located Mediterranean archipelago. The pollen record from this site provides new insight into the vegetation changes from 7280 to 1730 cal BP which correspond well with other regional records. The climate reconstruction for the area also provides strong correlation with southern (below 40° N) Mediterranean sites. Our interpretation suggests an initially open landscape during the early Neolithic, surrounding a large palaeobay, developing into a dense Pistacia scrubland ca. 6700 cal BP. From about 4450 cal BP the landscape once again becomes open, coinciding with the start of the Bronze Age on the archipelago. This period is concurrent with increased climatic instability (between 4500 and 3700 cal BP) which is followed by a gradual decrease in summer moisture availability in the late Holocene. During the early Roman occupation period (1972 to 1730 cal BP) the landscape remains generally open with a moderate increase in Olea. This increase, corresponds to archaeological evidence for olive oil production in the area, along with increases in cultivated crop taxa and associated ruderal species, as well as a rise in fire events. The Maltese archipelago provides important insight into vegetation, human impacts and climatic changes in an island context during the Holocene.

7300 years of vegetation history and climate for NW Malta: a Holocene perspective

NASA Astrophysics Data System (ADS)

Gambin, B.; Andrieu-Ponel, V.; Médail, F.; Marriner, N.; Peyron, O.; Montade, V.; Gambin, T.; Morhange, C.; Belkacem, D.; Djamali, M.

2016-02-01

This paper investigates the Holocene vegetation dynamics for Burmarrad in Northwest Malta and provides a pollen-based quantitative palaeoclimatic reconstruction for this centrally located Mediterranean archipelago. The pollen record from this site provides new insight into the vegetation changes from 7280 to 1730 cal BP which correspond well with other regional records. The climate reconstruction for the area also provides strong correlation with southern (below 40° N) Mediterranean sites. Our interpretation suggests an initially open landscape during the early Neolithic, surrounding a large palaeobay, developing into a dense Pistacia scrubland ca. 6700 cal BP. From about 4450 cal BP the landscape once again becomes open, coinciding with the start of the Bronze Age on the archipelago. This period is concurrent with increased climatic instability (between 4500 and 3700 cal BP) which is followed by a gradual decrease in summer moisture availability in the late Holocene. During the early Roman occupation period (1972-1730 cal BP) the landscape remains generally open with a moderate increase in Olea. This increase corresponds to archaeological evidence for olive oil production in the area, along with increases in cultivated crop taxa and associated ruderal species, as well as a rise in fire events. The Maltese archipelago provides important insight into vegetation, human impacts, and climatic changes in an island context during the Holocene.

Participation of Xenopus Elr-type Proteins in Vegetal mRNA Localization during Oogenesis*

PubMed Central

Arthur, Patrick K.; Claussen, Maike; Koch, Susanne; Tarbashevich, Katsiaryna; Jahn, Olaf; Pieler, Tomas

2009-01-01

Directional transport of specific mRNAs is of primary biological relevance. In Xenopus oocytes, mRNA localization to the vegetal pole is important for germ layer formation and germ cell development. Using a biochemical approach, we identified Xenopus Elr-type proteins, homologs of the Hu/ELAV proteins, as novel components of the vegetal mRNA localization machinery. They bind specifically to the localization elements of several different vegetally localizing Xenopus mRNAs, and they are part of one RNP together with other localization proteins, such as Vg1RBP and XStaufen 1. Blocking Elr-type protein binding by either localization element mutagenesis or antisense morpholino oligonucleotide-mediated masking of their target RNA structures, as well as overexpression of wild type and mutant ElrB proteins, interferes with vegetal localization in Xenopus oocytes. PMID:19458392

Vegetation of wetlands of the prairie pothole region

USGS Publications Warehouse

Kantrud, H.A.; Millar, J.B.; Van Der Valk, A.G.; van der Valk, A.

1989-01-01

Five themes dominate the literature dealing with the vegetation of palustrine and lacustrine wetlands of the prairie pothole region: environmental conditions (water or moisture regime, salinity), agricultural disturbances (draining, grazing, burning, sedimentation, etc.), vegetation dynamics, zonation patterns, and classification of the wetlands.The flora of a prairie wetland is a function of its water regime, salinity, and disturbance by man. Within a pothole, water depth and duration determines distribution of species. In potholes deep enough to have standing water even during droughts, the central zone will be dominated by submersed species (open water). In wetlands that go dry during periods of drought or annually, the central zone will be dominated by either tall emergent species (deep marsh) or midheight emergents (shallow marsh), respectively. Potholes that are only flooded briefly in the spring are dominated by grasses, sedges, and forbs (wet meadow). Within a pothole, the depth of standing water in the deepest, usually central, part of the basin determines how many zones will be present. Lists of species associated with different water regimes and salinity levels are presented.Disturbances due to agricultural activities have impacted wetlands throughout the region. Drainage has eliminated many potholes, particularly in the southern and eastern parts of the region. Grazing, mowing, and burning have altered the composition of pothole vegetation. The composition of different vegetation types impacted by grazing, haying, and cultivation is presented in a series of tables. Indirect impacts of agriculture (increased sediment, nutrient, and pesticide inputs) are widespread over the region, but their impacts on the vegetation have never been studied.Because of the periodic droughts and wet periods, many palustrine and lacustrine wetlands undergo vegetation cycles associated with water-level changes produced by these wet-dry cycles. Periods of above normal precipitation can raise water levels high enough to drown out emergent vegetation or produce 'eat outs' due to increases in the size of muskrat populations that accompany periods of high water. The elimination of emergents creates a lake marsh dominated by submersed vegetation. During the next drought when the marsh bottom is exposed by receding water levels (a drawdown), seeds of emergents and mudflat annuals in the soil (the seed bank) germinate (the dry marsh stage). When the marsh refloods, ending the dry marsh stage, the emergents survive and spread vegetatively. This is the regenerating marsh. This stage continues until high water again eliminates the emergents, starting the next degenerating stage.Zonation patterns are conspicuous because each zone often is dominated by a single species that has a lifeform different from those in adjacent zones. The species composition of each zone is a function of its environment (water or moisture regime, salinity, and disturbance history). Within a zone it may take a year or more for species composition to adjust to a change of environmental conditions. These lags sometimes result in abnormal zonation patterns, particularly after a change in water level.Classification of prairie wetlands is more difficult than for most other wetland type, because of these vegetation cycles. Early attempts to classify prairie wetlands did not take the dynamic nature of their vegetation into account. Stewart and Kantrud (1971) developed a classification system for prairie potholes that recognized different phases of vegetation zones dominated by deep marsh species. It used the composition of the vegetation in the deepest part (zone) of a pothole as an indicator of its water-level regime and water chemistry. The application of the national wetland classification system of Cowardin et al. (1979) to potholes is also discussed, and lists of species that characterize the various dominance types associated with the subclasses in this system are presented.

The Effects of Vegetative Type, Edges, Fire History, Rainfall and Management in Fire-Maintained Ecosystems

NASA Technical Reports Server (NTRS)

Breininger, David R.; Foster, Tammy E.; Carter, Geoffrey M.; Duncan, Brean W.; Stolen, Eric D.; Lyon, James E.

2017-01-01

The combined effects of repeated fires, climate, and landscape features (e.g., edges) need greater focus in fire ecology studies, which usually emphasize characteristics of the most recent fire and not fire history. Florida scrub-jays are an imperiled, territorial species that prefer medium (1.2-1.7 m) shrub heights. We measured short, medium, and tall habitat quality states annually within 10 ha grid cells that represented potential territories because frequent fires and vegetative recovery cause annual variation in habitat quality. We used multistate models and model selection to test competing hypotheses about how transition probabilities between states varied annually as functions of environmental covariates. Covariates included vegetative type, edges, precipitation, openings (gaps between shrubs), mechanical cutting, and fire characteristics. Fire characteristics not only included an annual presenceabsence of fire covariate, but also fire history covariates: time since the previous fire, the maximum fire-free interval, and the number of repeated fires. Statistical models with support included many covariates for each transition probability, often including fire history, interactions and nonlinear relationships. Tall territories resulted from 28 years of fire suppression and habitat fragmentation that reduced the spread of fires across landscapes. Despite 35 years of habitat restoration and prescribed fires, half the territories remained tall suggesting a regime shift to a less desirable habitat condition. Measuring territory quality states and environmental covariates each year combined with multistate modeling provided a useful empirical approach to quantify the effects of repeated fire in combinations with environmental variables on transition probabilities that drive management strategies and ecosystem change.

The Effects of Vegetative Type, Edges, Fire History, Rainfall and Management in Fire-Maintained Habitat

NASA Technical Reports Server (NTRS)

Breininger, David R.; Foster, Tammy E.; Carter, Geoffrey M.; Duncan, Brean W.; Stolen, Eric D.; Lyon, James E.

2018-01-01

The combined effects of fire history, climate, and landscape features (e.g., edges) on habitat specialists need greater focus in fire ecology studies, which usually only emphasize characteristics of the most recent fire. Florida scrub-jays are an imperiled, territorial species that prefer medium (1.2-1.7 m) shrub heights, which are dynamic because of frequent fires. We measured short, medium, and tall habitat quality states annually within 10 ha grid cells (that represented potential territories) because fires and vegetative recovery cause annual variation in habitat quality. We used multistate models and model selection to test competing hypotheses about how transition probabilities vary between states as functions of environmental covariates. Covariates included vegetative type, edges (e.g., roads, forests), precipitation, openings (gaps between shrubs), mechanical cutting, and fire characteristics. Fire characteristics not only included an annual presence/absence of fire covariate, but also fire history covariates: time since the previous fire, the longest fire-free interval, and the number of repeated fires. Statistical models with support included many covariates for each transition probability, often including fire history, interactions and nonlinear relationships. Tall territories resulted from 28 years of fire suppression and habitat fragmentation that reduced the spread of fires across landscapes. Despite 35 years of habitat restoration and prescribed fires, half the territories remained tall suggesting a regime shift to a less desirable habitat condition. Edges reduced the effectiveness of fires in setting degraded scrub and flatwoods into earlier successional states making mechanical cutting an important tool to compliment frequent prescribed fires.

[Correlation analysis on normalized difference vegetation index (NDVI) of different vegetations and climatic factors in Southwest China].

PubMed

Zhang, Yuan-Dong; Zhang, Xiao-He; Liu, Shi-Rong

2011-02-01

Based on the 1982-2006 NDVI remote sensing data and meteorological data of Southwest China, and by using GIS technology, this paper interpolated and extracted the mean annual temperature, annual precipitation, and drought index in the region, and analyzed the correlations of the annual variation of NDVI in different vegetation types (marsh, shrub, bush, grassland, meadow, coniferous forest, broad-leaved forest, alpine vegetation, and cultural vegetation) with corresponding climatic factors. In 1982-2006, the NDVI, mean annual temperature, and annual precipitation had an overall increasing trend, and the drought index decreased. Particularly, the upward trend of mean annual temperature was statistically significant. Among the nine vegetation types, the NDVI of bush and mash decreased, and the downward trend was significant for bush. The NDVI of the other seven vegetation types increased, and the upward trend was significant for coniferous forest, meadow, and alpine vegetation, and extremely significant for shrub. The mean annual temperature in the areas with all the nine vegetation types increased significantly, while the annual precipitation had no significant change. The drought index in the areas with marsh, bush, and cultural vegetation presented an increasing trend, that in the areas with meadow and alpine vegetation decreased significantly, and this index in the areas with other four vegetation types had an unobvious decreasing trend. The NDVI of shrub and coniferous forest had a significantly positive correlation with mean annual temperature, and that of shrub and meadow had significantly negative correlation with drought index. Under the conditions of the other two climatic factors unchanged, the NDVI of coniferous forest, broad-leaved forest, and alpine vegetation showed the strongest correlation with mean annual temperature, that of grass showed the strongest correlation with annual precipitation, and the NDVI of mash, shrub, grass, meadow, and cultural vegetation showed the strongest correlation with drought index. There existed definite correlations among the climatic factors. If the correlations among the climatic factors were ignored, the significant level of the correlations between NDVI and climatic factors would be somewhat reduced.

The role of arbuscular mycorrhizal fungi in grain production and nutrition of sorghum genotypes: Enhancing sustainability through plant-microbial partnership

USDA-ARS?s Scientific Manuscript database

The role of arbuscular mycorrhizal (AM) fungi and fertilization in sorghum grain production and quality was assessed for 3 hybrid genotypes, 2 open-pollinated African genotypes, and 1 open-pollinated Latin American genotype. The open-pollinated genotypes produced an average of 206% more vegetative b...

Nationwide classification of forest types of India using remote sensing and GIS.

PubMed

Reddy, C Sudhakar; Jha, C S; Diwakar, P G; Dadhwal, V K

2015-12-01

India, a mega-diverse country, possesses a wide range of climate and vegetation types along with a varied topography. The present study has classified forest types of India based on multi-season IRS Resourcesat-2 Advanced Wide Field Sensor (AWiFS) data. The study has characterized 29 land use/land cover classes including 14 forest types and seven scrub types. Hybrid classification approach has been used for the classification of forest types. The classification of vegetation has been carried out based on the ecological rule bases followed by Champion and Seth's (1968) scheme of forest types in India. The present classification scheme has been compared with the available global and national level land cover products. The natural vegetation cover was estimated to be 29.36% of total geographical area of India. The predominant forest types of India are tropical dry deciduous and tropical moist deciduous. Of the total forest cover, tropical dry deciduous forests occupy an area of 2,17,713 km(2) (34.80%) followed by 2,07,649 km(2) (33.19%) under tropical moist deciduous forests, 48,295 km(2) (7.72%) under tropical semi-evergreen forests and 47,192 km(2) (7.54%) under tropical wet evergreen forests. The study has brought out a comprehensive vegetation cover and forest type maps based on inputs critical in defining the various categories of vegetation and forest types. This spatially explicit database will be highly useful for the studies related to changes in various forest types, carbon stocks, climate-vegetation modeling and biogeochemical cycles.

Sentinel-1 backscatter sensitivity to vegetation dynamics at the field scale.

NASA Astrophysics Data System (ADS)

Vreugdenhil, Mariette; Eder, Alexander; Bauer-Marschallinger, Bernhard; Cao, Senmao; Naeimi, Vahid; Oismueller, Markus; Strauss, Peter; Wagner, Wolfgang

2017-04-01

Vegetation monitoring is pivotal to improve our understanding of the role vegetation dynamics play in the global carbon-, energy- and hydrological cycle. And with the increasing stress on food supply due to the growing world populating and changing climate, vegetation monitoring is of great importance in agricultural areas. By closely tracking crop conditions, droughts and subsequent crop losses could be mitigated. Sensors operating in the microwave domain are sensitive to several surface characteristics, including soil moisture and vegetation. Hence, spaceborne microwave remote sensing provides the means to monitor vegetation and soil conditions on different scales, ranging from field scale to global scale. However, it also presents a challenge since multiple combinations of soil and vegetation characteristics can lead to a similar measurement. Copernicus Sentinel-1 (S-1) is a series of two satellites, developed by the European Space Agency (ESA) , which carry C-band Synthetic Aperture Radars. The C-SAR sensors provide VV, HH, VH and HV backscatter at a 5 m by 20 m spatial resolution. The temporal revisit time of the two satellites is 3-6 days. With their unique capacity for temporally dense and spatially detailed data, the S-1 satellite series provides for the first time the chance to investigate vegetation dynamics at high temporal and spatial resolution. The aim of this study is to assess the sensitivity of Sentinel-1 backscatter to vegetation dynamics. The study is performed in the Hydrological Open Air Laboratory (HOAL), which is a 66 hectare large catchment located in Petzenkirchen, Austria. In the HOAL several vegetation parameters were measured during the course of the growing season (2016) at the overpass time of S-1a. Vegetation height was obtained ten times for the whole catchment, using georeferenced photos made by a motorized paraglider and a Land Surface Model. In addition, vegetation water content, Leaf Area Index and soil moisture were measured in four different cropfields. An in situ soil moisture network provides continuous soil moisture measurements at 31 locations within the catchment. Different polarizations and ratios thereof were calculated and compared, both spatially and temporally, to the in situ measurements of vegetation height, LAI, vegetation water content and soil moisture. Preliminary results show a clear spatial pattern in cross-polarized backscatter, which is related to different crop types. Time series analysis suggests that a ratio between cross- and co-polarized backscatter is affected by both vegetation water content and vegetation structure. This presentation will provide a comprehensive assessment of Sentinel-1's capability for monitoring of vegetation over croplands, using in situ reference data obtained over a full growing season.

Ecosystem services: Urban parks under a magnifying glass.

PubMed

Mexia, Teresa; Vieira, Joana; Príncipe, Adriana; Anjos, Andreia; Silva, Patrícia; Lopes, Nuno; Freitas, Catarina; Santos-Reis, Margarida; Correia, Otília; Branquinho, Cristina; Pinho, Pedro

2018-01-01

Urban areas' population has grown during the last century and it is expected that over 60% of the world population will live in cities by 2050. Urban parks provide several ecosystem services that are valuable to the well-being of city-dwellers and they are also considered a nature-based solution to tackle multiple environmental problems in cities. However, the type and amount of ecosystem services provided will vary with each park vegetation type, even within same the park. Our main goal was to quantify the trade-offs in ecosystem services associated to different vegetation types, using a spatially detailed approach. Rather than relying solely on general vegetation typologies, we took a more ecologically oriented approach, by explicitly considering different units of vegetation structure and composition. This was demonstrated in a large park (44ha) located in the city of Almada (Lisbon metropolitan area, Portugal), where six vegetation units were mapped in detail and six ecosystem services were evaluated: carbon sequestration, seed dispersal, erosion prevention, water purification, air purification and habitat quality. The results showed that, when looking at the park in detail, some ecosystem services varied greatly with vegetation type. Carbon sequestration was positively influenced by tree density, independently of species composition. Seed dispersal potential was higher in lawns, and mixed forest provided the highest amount of habitat quality. Air purification service was slightly higher in mixed forest, but was high in all vegetation types, probably due to low background pollution, and both water purification and erosion prevention were high in all vegetation types. Knowing the type, location, and amount of ecosystem services provided by each vegetation type can help to improve management options based on ecosystem services trade-offs and looking for win-win situations. The trade-offs are, for example, very clear for carbon: tree planting will boost carbon sequestration regardless of species, but may not be enough to increase habitat quality. Moreover, it may also negatively influence seed dispersal service. Informed practitioners can use this ecological knowledge to promote the role of urban parks as a nature-based solution to provide multiple ecosystem services, and ultimately improve the design and management of the green infrastructure. This will also improve the science of Ecosystem Services, acknowledging that the type of vegetation matters for the provision of ecosystem services and trade-offs analysis. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Grassland plant composition alters vehicular disturbance effects in Kansas, USA.

PubMed

Dickson, Timothy L; Wilsey, Brian J; Busby, Ryan R; Gebhart, Dick L

2008-05-01

Many "natural" areas are exposed to military or recreational off-road vehicles. The interactive effects of different types of vehicular disturbance on vegetation have rarely been examined, and it has been proposed that some vegetation types are less susceptible to vehicular disturbance than others. At Fort Riley, Kansas, we experimentally tested how different plant community types changed after disturbance from an M1A1 Abrams tank driven at different speeds and turning angles during different seasons. The greatest vegetation change was observed because of driving in the spring in wet soils and the interaction of turning while driving fast (vegetation change was measured with Bray-Curtis dissimilarity). We found that less vegetation change occurred in communities with high amounts of native prairie vegetation than in communities with high amounts of introduced C(3) grasses, which is the first experimental evidence we are aware of that suggests plant communities dominated by introduced C(3) grasses changed more because of vehicular disturbance than communities dominated by native prairie grasses. We also found that vegetation changed linearly with vehicular disturbance intensity, suggesting that at least initially there was no catastrophic shift in vegetation beyond a certain disturbance intensity threshold. Overall, the intensity of vehicular disturbance appeared to play the greatest role in vegetation change, but the plant community type also played a strong role and this should be considered in land use planning. The reasons for greater vegetation change in introduced C(3) grass dominated areas deserve further study.

Characterizing Exterior and Interior Tropical Forest Structure Variability with Full-Waveform Airborne LIDAR Data in Lopé, Gabon

NASA Astrophysics Data System (ADS)

Marselis, S.; Tang, H.; Blair, J. B.; Hofton, M. A.; Armston, J.; Dubayah, R.

2017-12-01

Terrestrial ecotones, transition zones between ecological systems, have been identified as important regions to monitor the effects of environmental and human pressures on ecosystems. To observe such changes, the variability in vegetation horizontal and vertical structure must be characterized. The objective of this study is to quantify changes in vegetation structure in a tropical forest-savanna mosaic using airborne waveform lidar data. The study area is located in the northern part of the Lopé National Park in Gabon and is comprised of the vegetation types: savanna, colonizing forest, monodominant Okoumé forest, young Marantaceae forest and mixed Marantaceae forest. The lidar data were collected by the Land Vegetation and Ice Sensor (LVIS) in early March 2016, during the AfriSAR campaign. Metrics derived from the LVIS waveforms were then used to classify the five main vegetation types and characterize observed structural variability within types and across ecotones. Several supervised and unsupervised classification alogrithms, in combination with statistical analysis, were applied. The investigated methods are promising in their use to directly describe the structural variability within and between different vegetation types, map these vegetation types and the extent and location of their transition zones, and to characterize, among other attributes, the sharpness and width of such ecotones. These results provide important information in ecosystem studies as these methods can be used to study changes in vegetation structure, species-specific habitat, or the effects of deforestation and other human and natural pressures on the exterior and interior forest structure. These methods thus provide ample opportunity to assess the vegetation structure in degraded and second growth tropical forests to explore effects of e.g. grazing, logging or fragmentation. From this study we can conclude that lidar waveform remote sensing is highly useful in distinguishing vegetation types and their transition zones which will be increasingly important when assessing the impact of natural and human pressures on the world's tropical forests.

Classification and description of world formation types

Treesearch

D. Faber-Langendoen; T. Keeler-Wolf; D. Meidinger; C. Josse; A. Weakley; D. Tart; G. Navarro; B. Hoagland; S. Ponomarenko; G. Fults; Eileen Helmer

2016-01-01

An ecological vegetation classification approach has been developed in which a combination of vegetation attributes (physiognomy, structure, and floristics) and their response to ecological and biogeographic factors are used as the basis for classifying vegetation types. This approach can help support international, national, and subnational classification efforts. The...

Vegetation, plant biomass, and net primary productivity patterns in the Canadian Arctic

NASA Astrophysics Data System (ADS)

Gould, W. A.; Raynolds, M.; Walker, D. A.

2003-01-01

We have developed maps of dominant vegetation types, plant functional types, percent vegetation cover, aboveground plant biomass, and above and belowground annual net primary productivity for Canada north of the northern limit of trees. The area mapped covers 2.5 million km2 including glaciers. Ice-free land covers 2.3 million km2 and represents 42% of all ice-free land in the Circumpolar Arctic. The maps combine information on climate, soils, geology, hydrology, remotely sensed vegetation classifications, previous vegetation studies, and regional expertise to define polygons drawn using photo-interpretation of a 1:4,000,000 scale advanced very high resolution radiometer (AVHRR) color infrared image basemap. Polygons are linked to vegetation description, associated properties, and descriptive literature through a series of lookup tables in a graphic information systems (GIS) database developed as a component of the Circumpolar Arctic Vegetation Map (CAVM) project. Polygons are classified into 20 landcover types including 17 vegetation types. Half of the region is sparsely vegetated (<50% vegetation cover), primarily in the High Arctic (bioclimatic subzones A-C). Whereas most (86%) of the estimated aboveground plant biomass (1.5 × 1015 g) and 87% of the estimated above and belowground annual net primary productivity (2.28 × 1014 g yr-1) are concentrated in the Low Arctic (subzones D and E). The maps present more explicit spatial patterns of vegetation and ecosystem attributes than have been previously available, the GIS database is useful in summarizing ecosystem properties and can be easily updated and integrated into circumpolar mapping efforts, and the derived estimates fall within the range of current published estimates.

Preliminary studies of elevated atmospheric CO/sub 2/ on conifers, May 1-December 30, 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helms, J.A.

1985-01-01

The original scope of work consisted of two parts: Intensive physiological studies of Pinus ponderosa seedlings and saplings that were continuously exposed to various levels of CO/sub 2/ and SO/sub 2/ in open-topped chambers. Site selection and preparation in anticipation of DOE approval of a proposed 5-year project on effects of long-term exposure of forest vegetation to enhanced CO/sub 2/. Establishment of 5 Nelder-type plots utilizing 5 western conifers to permit fundamental studies on the physiological bases of tree-to-tree competition. Because the DOE project was not funded, site selection was abandoned.

Vegetable and Fruit Intake and Fracture-Related Hospitalisations: A Prospective Study of Older Women

PubMed Central

Blekkenhorst, Lauren C.; Hodgson, Jonathan M.; Lewis, Joshua R.; Devine, Amanda; Woodman, Richard J.; Lim, Wai H.; Wong, Germaine; Zhu, Kun; Bondonno, Catherine P.; Ward, Natalie C.; Prince, Richard L.

2017-01-01

The importance of vegetable and fruit intakes for the prevention of fracture in older women is not well understood. Few studies have explored vegetable and fruit intakes separately, or the associations of specific types of vegetables and fruits with fracture hospitalisations. The objective of this study was to examine the associations of vegetable and fruit intakes, separately, and specific types of vegetables and fruits with fracture-related hospitalisations in a prospective cohort of women aged ≥70 years. Vegetable and fruit intakes were assessed at baseline (1998) in 1468 women using a food frequency questionnaire. The incidence of fracture-related hospitalisations over 14.5 years of follow-up was determined using the Hospital Morbidity Data Collection, linked via the Western Australian Data Linkage System. Fractures were identified in 415 (28.3%) women, of which 158 (10.8%) were hip fractures. Higher intakes of vegetables, but not fruits, were associated with lower fracture incidence. In multivariable-adjusted models for vegetable types, cruciferous and allium vegetables were inversely associated with all fractures, with a hazard ratio (HR) (95% confidence interval) of 0.72 (0.54, 0.95) and 0.66 (0.49, 0.88), respectively, for the highest vs. lowest quartiles. Increasing vegetable intake, with an emphasis on cruciferous and allium vegetables, may prevent fractures in older postmenopausal women. PMID:28524097

Evaluation of fecal indicators and pathogens in a beef cattle feedlot vegetative treatment system

USDA-ARS?s Scientific Manuscript database

Runoff from open-lot animal feeding areas contains microorganisms that may adversely affect human and animal health if not properly managed. One alternative to full manure containment systems is a vegetative treatment system (VTS) that collects runoff in a sediment basin and then applies it to a per...

Mitigation in riparian areas: Questions, concerns and recommendations

Treesearch

Tony Barron

1996-01-01

The management of seven thousand acres in the Rio Grande Valley State Park presents a unique management challenge and opportunity. The Open Space Division defines a riparian area as "any area of land influenced directly by permanent water". The influence of permanent water or water flows produces visible vegetation and visible vegetative characteristics on...

MODELING FLOW PATTERNS IN A SMALL VEGETATED AREA IN THE NORTHERN CHICHUAHUAN DESERT USING QUIC ( QUIC URBAN AND INDUSTRIAL COMPLEX )

EPA Science Inventory

Sandstorms are frequent in the northern Chihuahuan Desert in New Mexico, an area characterized by open areas lacking vegetation, individual mesquite bushes, and mesquite coppice dunes. Field measurements of sand fluxes and wind velocities over a two year period provided a descri...

Arabidopsis CALCINEURIN B-LIKE10 Functions Independently of the SOS Pathway during Reproductive Development in Saline Conditions1[OPEN

PubMed Central

Smith, Steven E.; Schumaker, Karen S.

2016-01-01

The accumulation of sodium in soil (saline conditions) negatively affects plant growth and development. The Salt Overly Sensitive (SOS) pathway in Arabidopsis (Arabidopsis thaliana) functions to remove sodium from the cytosol during vegetative development preventing its accumulation to toxic levels. In this pathway, the SOS3 and CALCINEURIN B-LIKE10 (CBL10) calcium sensors interact with the SOS2 protein kinase to activate sodium/proton exchange at the plasma membrane (SOS1) or vacuolar membrane. To determine if the same pathway functions during reproductive development in response to salt, fertility was analyzed in wild type and the SOS pathway mutants grown in saline conditions. In response to salt, CBL10 functions early in reproductive development before fertilization, while SOS1 functions mostly after fertilization when seed development begins. Neither SOS2 nor SOS3 function in reproductive development in response to salt. Loss of CBL10 function resulted in reduced anther dehiscence, shortened stamen filaments, and aborted pollen development. In addition, cbl10 mutant pistils could not sustain the growth of wild-type pollen tubes. These results suggest that CBL10 is critical for reproductive development in the presence of salt and that it functions in different pathways during vegetative and reproductive development. PMID:26979332

Pollen assemblages as paleoenvironmental proxies in the Florida Everglades

USGS Publications Warehouse

Willard, D.A.; Weimer, L.M.; Riegel, W.L.

2001-01-01

Analysis of 170 pollen assemblages from surface samples in eight vegetation types in the Florida Everglades indicates that these wetland sub-environments are distinguishable from the pollen record and that they are useful proxies for hydrologic and edaphic parameters. Vegetation types sampled include sawgrass marshes, cattail marshes, sloughs with floating aquatics, wet prairies, brackish marshes, tree islands, cypress swamps, and mangrove forests. The distribution of these vegetation types is controlled by specific environmental parameters, such as hydrologic regime, nutrient availability, disturbance level, substrate type, and salinity; ecotones between vegetation types may be sharp. Using R-mode cluster analysis of pollen data, we identified diagnostic species groupings; Q-mode cluster analysis was used to differentiate pollen signatures of each vegetation type. Cluster analysis and the modern analog technique were applied to interpret vegetational and environmental trends over the last two millennia at a site in Water Conservation Area 3A. The results show that close modern analogs exist for assemblages in the core and indicate past hydrologic changes at the site, correlated with both climatic and land-use changes. The ability to differentiate marshes with different hydrologic and edaphic requirements using the pollen record facilitates assessment of relative impacts of climatic and anthropogenic changes on this wetland ecosystem on smaller spatial and temporal scales than previously were possible. ?? 2001 Elsevier Science B.V.

Ecological consequences of Late Quaternary extinctions of megafauna

PubMed Central

Johnson, C.N.

2009-01-01

Abstract Large herbivorous vertebrates have strong interactions with vegetation, affecting the structure, composition and dynamics of plant communities in many ways. Living large herbivores are a small remnant of the assemblages of giants that existed in most terrestrial ecosystems 50 000 years ago. The extinction of so many large herbivores may well have triggered large changes in plant communities. In several parts of the world, palaeoecological studies suggest that extinct megafauna once maintained vegetation openness, and in wooded landscapes created mosaics of different structural types of vegetation with high habitat and species diversity. Following megafaunal extinction, these habitats reverted to more dense and uniform formations. Megafaunal extinction also led to changes in fire regimes and increased fire frequency due to accumulation of uncropped plant material, but there is a great deal of variation in post-extinction changes in fire. Plant communities that once interacted with extinct large herbivores still contain many species with obsolete defences against browsing and non-functional adaptations for seed dispersal. Such plants may be in decline, and, as a result, many plant communities may be in various stages of a process of relaxation from megafauna-conditioned to megafauna-naive states. Understanding the past role of giant herbivores provides fundamental insight into the history, dynamics and conservation of contemporary plant communities. PMID:19324773

Metabolic engineering of biomass for high energy density: oilseed-like triacylglycerol yields from plant leaves

PubMed Central

Vanhercke, Thomas; El Tahchy, Anna; Liu, Qing; Zhou, Xue-Rong; Shrestha, Pushkar; Divi, Uday K; Ral, Jean-Philippe; Mansour, Maged P; Nichols, Peter D; James, Christopher N; Horn, Patrick J; Chapman, Kent D; Beaudoin, Frederic; Ruiz-López, Noemi; Larkin, Philip J; de Feyter, Robert C; Singh, Surinder P; Petrie, James R

2014-01-01

High biomass crops have recently attracted significant attention as an alternative platform for the renewable production of high energy storage lipids such as triacylglycerol (TAG). While TAG typically accumulates in seeds as storage compounds fuelling subsequent germination, levels in vegetative tissues are generally low. Here, we report the accumulation of more than 15% TAG (17.7% total lipids) by dry weight in Nicotiana tabacum (tobacco) leaves by the co-expression of three genes involved in different aspects of TAG production without severely impacting plant development. These yields far exceed the levels found in wild-type leaf tissue as well as previously reported engineered TAG yields in vegetative tissues of Arabidopsis thaliana and N. tabacum. When translated to a high biomass crop, the current levels would translate to an oil yield per hectare that exceeds those of most cultivated oilseed crops. Confocal fluorescence microscopy and mass spectrometry imaging confirmed the accumulation of TAG within leaf mesophyll cells. In addition, we explored the applicability of several existing oil-processing methods using fresh leaf tissue. Our results demonstrate the technical feasibility of a vegetative plant oil production platform and provide for a step change in the bioenergy landscape, opening new prospects for sustainable food, high energy forage, biofuel and biomaterial applications. PMID:24151938

Response of respiration and nutrient availability to drying and rewetting in soil from a semi-arid woodland depends on vegetation patch and a recent wildfire

NASA Astrophysics Data System (ADS)

Sun, Q.; Meyer, W. S.; Koerber, G. R.; Marschner, P.

2015-08-01

Semi-arid woodlands, which are characterised by patchy vegetation interspersed with bare, open areas, are frequently exposed to wildfire. During summer, long dry periods are occasionally interrupted by rainfall events. It is well known that rewetting of dry soil induces a flush of respiration. However, the magnitude of the flush may differ between vegetation patches and open areas because of different organic matter content, which could be further modulated by wildfire. Soils were collected from under trees, under shrubs or in open areas in unburnt and burnt sandy mallee woodland, where part of the woodland experienced a wildfire which destroyed or damaged most of the aboveground plant parts 4 months before sampling. In an incubation experiment, the soils were exposed to two moisture treatments: constantly moist (CM) and drying and rewetting (DRW). In CM, soils were incubated at 80 % of maximum water holding capacity (WHC) for 19 days; in DRW, soils were dried for 4 days, kept dry for another 5 days, then rewetted to 80 % WHC and maintained at this water content until day 19. Soil respiration decreased during drying and was very low in the dry period; rewetting induced a respiration flush. Compared to soil under shrubs and in open areas, cumulative respiration per gram of soil in CM and DRW was greater under trees, but lower when expressed per gram of total organic carbon (TOC). Organic matter content, available P, and microbial biomass C, but not available N, were greater under trees than in open areas. Wild fire decreased the flush of respiration per gram of TOC in the open areas and under shrubs, and reduced TOC and microbial biomass C (MBC) concentrations only under trees, but had little effect on available N and P concentrations. We conclude that the impact of wildfire and DRW events on nutrient cycling differs among vegetation patches of a native semi-arid woodland which is related to organic matter amount and availability.

Woodland Mapping at Single-Tree Levels Using Object-Oriented Classification of Unmanned Aerial Vehicle (uav) Images

NASA Astrophysics Data System (ADS)

Chenari, A.; Erfanifard, Y.; Dehghani, M.; Pourghasemi, H. R.

2017-09-01

Remotely sensed datasets offer a reliable means to precisely estimate biophysical characteristics of individual species sparsely distributed in open woodlands. Moreover, object-oriented classification has exhibited significant advantages over different classification methods for delineation of tree crowns and recognition of species in various types of ecosystems. However, it still is unclear if this widely-used classification method can have its advantages on unmanned aerial vehicle (UAV) digital images for mapping vegetation cover at single-tree levels. In this study, UAV orthoimagery was classified using object-oriented classification method for mapping a part of wild pistachio nature reserve in Zagros open woodlands, Fars Province, Iran. This research focused on recognizing two main species of the study area (i.e., wild pistachio and wild almond) and estimating their mean crown area. The orthoimage of study area was consisted of 1,076 images with spatial resolution of 3.47 cm which was georeferenced using 12 ground control points (RMSE=8 cm) gathered by real-time kinematic (RTK) method. The results showed that the UAV orthoimagery classified by object-oriented method efficiently estimated mean crown area of wild pistachios (52.09±24.67 m2) and wild almonds (3.97±1.69 m2) with no significant difference with their observed values (α=0.05). In addition, the results showed that wild pistachios (accuracy of 0.90 and precision of 0.92) and wild almonds (accuracy of 0.90 and precision of 0.89) were well recognized by image segmentation. In general, we concluded that UAV orthoimagery can efficiently produce precise biophysical data of vegetation stands at single-tree levels, which therefore is suitable for assessment and monitoring open woodlands.

Consumption of vegetables and their relation with ultra-processed foods in Brazil

PubMed Central

Canella, Daniela Silva; Louzada, Maria Laura da Costa; Claro, Rafael Moreira; Costa, Janaina Calu; Bandoni, Daniel Henrique; Levy, Renata Bertazzi; Martins, Ana Paula Bortoletto

2018-01-01

ABSTRACT OBJECTIVE To characterize the household purchase and the individual consumption of vegetables in Brazil and to analyze their relation with the consumption of ultra-processed foods. METHODS We have used data on the purchase of food for household consumption and individual consumption from the 2008–2009 Brazilian Household Budget Survey. The Brazilian Household Budget Survey studied the purchase of food of 55,970 households and the food consumption of 34,003 individuals aged 10 years and over. The foods of interest in this study were vegetables (excluding roots and tubers) and ultra-processed foods. We have described the amount of vegetables (grams) purchased and consumed by all Brazilians and according to the quintiles of caloric intake of ultra-processed food. To this end, we have calculated the crude and predicted values obtained by regression models adjusted for sociodemographic variables. We have analyzed the most commonly purchased types of vegetables (% in the total amount) and, in relation to individual food consumption, the variety of vegetables consumed (absolute number), the participation (%) of the types of culinary preparations based on vegetables, and the time of consumption. RESULTS The adjusted mean household purchase of vegetables was 42.9 g/per capita/day. The adjusted mean individual consumption was 46.1 g. There was an inverse relation between household purchase and individual consumption of vegetables and ultra-processed foods. Ten types of vegetables account for more than 80% of the total amount usually purchased. The variety consumed was, on average, 1.08 type/per capita/day. Approximately 60% of the vegetables were eaten raw, and the amount consumed at lunch was twice that consumed at dinner; individuals with higher consumption of ultra-processed foods tended to consume even less vegetables at dinner. CONCLUSIONS The consumption of vegetables in Brazil is insufficient, and this is worse among individuals with higher consumption of ultra-processed foods. The most frequent habit was to consume raw vegetables at lunch and with limited variety. PMID:29791530

Classification of simple vegetation types using POLSAR image data

NASA Technical Reports Server (NTRS)

Freeman, A.

1993-01-01

Mapping basic vegetation or land cover types is a fairly common problem in remote sensing. Knowledge of the land cover type is a key input to algorithms which estimate geophysical parameters, such as soil moisture, surface roughness, leaf area index or biomass from remotely sensed data. In an earlier paper, an algorithm for fitting a simple three-component scattering model to POLSAR data was presented. The algorithm yielded estimates for surface scatter, double-bounce scatter and volume scatter for each pixel in a POLSAR image data set. In this paper, we show how the relative levels of each of the three components can be used as inputs to simple classifier for vegetation type. Vegetation classes include no vegetation cover (e.g. bare soil or desert), low vegetation cover (e.g. grassland), moderate vegetation cover (e.g. fully developed crops), forest and urban areas. Implementation of the approach requires estimates for the three components from all three frequencies available using the NASA/JPL AIRSAR, i.e. C-, L- and P-bands. The research described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration.

Alien plant invasion in mixed-grass prairie: Effects of vegetation type and anthropogenic disturbance

USGS Publications Warehouse

Larson, D.L.; Anderson, P.J.; Newton, W.

2001-01-01

The ability of alien plant species to invade a region depends not only on attributes of the plant, but on characteristics of the habitat being invaded. Here, we examine characteristics that may influence the success of alien plant invasion in mixed-grass prairie at Theodore Roosevelt National Park, in western North Dakota, USA. The park consists of two geographically separate units with similar vegetation types and management history, which allowed us to examine the effects of native vegetation type, anthropogenic disturbance, and the separate park units on the invasion of native plant communities by alien plant species common to counties surrounding both park units. If matters of chance related to availability of propagules and transient establishment opportunities determine the success of invasion, park unit and anthropogenic disturbance should better explain the variation in alien plant frequency. If invasibility is more strongly related to biotic or physical characteristics of the native plant communities, models of alien plant occurrence should include vegetation type as an explanatory variable. We examined >1300 transects across all vegetation types in both units of the park. Akaike's Information Criterion (AIC) indicated that the fully parameterized model, including the interaction among vegetation type, disturbance, and park unit, best described the distribution of both total number of alien plants per transect and frequency of alien plants on transects where they occurred. Although all vegetation types were invaded by alien plants, mesic communities had both greater numbers and higher frequencies of alien plants than did drier communities. A strong element of stochasticity, reflected in differences in frequencies of individual species between the two park units, suggests that prediction of risk of invasion will always involve uncertainty. In addition, despite well-documented associations between anthropogenic disturbance and alien plant invasion, five of the six most abundant alien species at Theodore Roosevelt National Park had distributions unrelated to disturbance. We recommend that vegetation type be explicitly taken into account when designing monitoring plans for alien species in natural areas.

Vegetative response to water availability on the San Carlos Apache Reservation

USGS Publications Warehouse

Petrakis, Roy; Wu, Zhuoting; McVay, Jason; Middleton, Barry R.; Dye, Dennis G.; Vogel, John M.

2016-01-01

On the San Carlos Apache Reservation in east-central Arizona, U.S.A., vegetation types such as ponderosa pine forests, pinyon-juniper woodlands, and grasslands have significant ecological, cultural, and economic value for the Tribe. This value extends beyond the tribal lands and across the Western United States. Vegetation across the Southwestern United States is susceptible to drought conditions and fluctuating water availability. Remotely sensed vegetation indices can be used to measure and monitor spatial and temporal vegetative response to fluctuating water availability conditions. We used the Moderate Resolution Imaging Spectroradiometer (MODIS)-derived Modified Soil Adjusted Vegetation Index II (MSAVI2) to measure the condition of three dominant vegetation types (ponderosa pine forest, woodland, and grassland) in response to two fluctuating environmental variables: precipitation and the Standardized Precipitation Evapotranspiration Index (SPEI). The study period covered 2002 through 2014 and focused on a region within the San Carlos Apache Reservation. We determined that grassland and woodland had a similar moderate to strong, year-round, positive relationship with precipitation as well as with summer SPEI. This suggests that these vegetation types respond negatively to drought conditions and are more susceptible to initial precipitation deficits. Ponderosa pine forest had a comparatively weaker relationship with monthly precipitation and summer SPEI, indicating that it is more buffered against short-term drought conditions. This research highlights the response of multiple, dominant vegetation types to seasonal and inter-annual water availability. This research demonstrates that multi-temporal remote sensing imagery can be an effective tool for the large scale detection of vegetation response to adverse impacts from climate change and support potential management practices such as increased monitoring and management of drought-affected areas. Different vegetation types displayed various responses to water availability, further highlighting the need for individual management plans for forest and woodland, especially considering the projected drier conditions in the Southwest U.S. and other arid or semi-arid regions around the world.

Defining the ecogeomorphic succession of land building for freshwater, intertidal wetlands in Wax Lake Delta, Louisiana

NASA Astrophysics Data System (ADS)

Olliver, Elizabeth A.; Edmonds, Douglas A.

2017-09-01

Land building in deltaic environments occurs when sediment discharged from a river mouth is deposited subaqueously and transitions to subaerial land. The transition from subaqueous deposition to subaerial land is a critical process that marks the creation of relatively stable land, yet it is unclear what controls the speed and style of this transition. We define how this transition, herein termed the land building succession, varies in time and space for the freshwater, intertidal wetlands in Wax Lake Delta, LA. Using remote sensing and field data we classify land cover into sediment, water, or vegetation classes at maximum and minimum biomass. We see two succession patterns within Wax Lake Delta. Deltaic islands near the apex are initially covered by sediment and open water. Through time, open water and sediment coverage decreases as vegetation coverage increases. On the other hand, distal islands show little sediment exposure through time. In both cases, all deltaic islands become covered with vegetation by 2015. As vegetation colonizes the island, the topography organizes into two platforms vertically separated by ∼0.35 m. The lower, intertidal platform occurs in the island interiors and is commonly inundated by water and dominated by subaqueous or floating vegetation. The upper, subaerial platform occurs along island edges and is dominated by a variety of vegetation species including Salix nigra, Colocasia esculenta, and Polygonum punctatum. It takes an average of ∼10 years for the intertidal platform to transition to the subaerial platform. These two platforms are separated by the tidal range measured in Atchafalaya Bay, and the different vegetation communities occupying each platform suggest they are a manifestation of multiple stable states and arise due to vegetation and sedimentation feedbacks.

The Change in the area of various land covers on the Tibetan Plateau during 1957-2015

NASA Astrophysics Data System (ADS)

Cuo, Lan; Zhang, Yongxin

2017-04-01

With average elevation of 4000 m and area of 2.5×106 km2, Tibetan Plateau hosts various fragile ecosystems such as perennial alpine meadow, perennial alpine steppe, temperate evergreen needleleaf trees, temperate deciduous trees, temperate shrub grassland, and barely vegetated desert. Perennial alpine meadow and steppe are the two dominant vegetation types on the heartland of the plateau. MODIS Leaf Area Index (LAI) ranges from 0 to 2 in most part of the plateau. With climate change, these ecosystems are expected to undergo alteration. This study uses a dynamic vegetation model - Lund-Potsdam-Jena (LPJ) to investigate the change of the barely vegetated area and other vegetation types caused by climate change during 1957-2015 on the Tibetan Plateau. Model simulated foliage projective coverage (FPC) and plant functional types (PFTs) are selected for the investigation. The model is evaluated first using both field surveyed land cover map and MODIS LAI images. Long term trends of vegetation FPC is examined. Decadal variations of vegetated and barely vegetated land are compared. The impacts of extreme precipitation, air temperature and CO2 on the expansion and contraction of barely vegetated and vegetated areas are shown. The study will identify the dominant climate factors in affecting the desert area in the region.

[The variability of vegetation beginning date of greenness period in spring in the north-south transect of eastern China based on NOAA NDVI].

PubMed

Wang, Zhi; Liu, Shi-rong; Sun, Peng-sen; Guo, Zhi-hua; Zhou, Lian-di

2010-10-01

NDVI based on NOAA/AVHRR from 1982 to 2003 are used to monitor variable rules for the growing season in spring of vegetation in the north-south transect of eastern China (NSTEC). The following, mainly, are included: (1) The changing speed of greenness period in spring of most regions in NSTEC is slow and correlation with the year is not distinct; (2) The regions in which greenness period in spring distinctly change mainly presented an advance; (3) The regions in which inter-annual fluctuation of greenness period in spring is over 10 days were found in 3 kinds of areas: the area covered with agricultural vegetation types; the areas covered with evergreen vegetation types; the areas covered with steppe vegetation types; (4) changes of vegetation greenness period in spring have spatio-temporal patterns.

The vegetation history of the last glacial-interglacial cycle in eastern New South Wales, Australia

NASA Astrophysics Data System (ADS)

Williams, N. J.; Harle, K. J.; Gale, S. J.; Heijnis, H.

2006-10-01

We present a reconstruction of the vegetation history of the last glacial-interglacial cycle (ca. 75 k cal. yr BP-present) at Redhead Lagoon, an enclosed lake basin in coastal, eastern New South Wales, Australia. The sequence of vegetation change at the site is broadly comparable with the pattern of climatically induced changes observed in many other pollen records in southeast Australia. Open woodland-herbland and woodland-forest communities correspond with glacial and interglacial periods respectively, with an additional change towards a more open understorey vegetation assemblage over the last 40 000 yr. The driest conditions appear to have occurred during the height of the last glacial (some time between 30 and 20 k cal. yr BP). This is consistent with other records from southeast Australia, and provides support for a poleward shift in the subtropical anticyclone belt and, less certainly, for the thesis that the Southern Hemisphere westerlies intensified during this period. In marked contrast to most sites in southeast Australia, Casuarinaceae dominates the pollen record through the height of the last glacial period and into the Holocene. The postglacial climatic amelioration is accompanied by the general reappearance of tree pollen in the record, by the disappearance of several open and disturbed environment indicator taxa, by increases in organic sediment deposition and pollen taxon diversity, and by higher water balances. While climate appears to have been the major control on patterns of vegetation change at this site throughout most of the last glacial-interglacial cycle, changes in depositional environment and hydrology have also played a role. Significantly, substantial increases in the rate and magnitude of many indicators of environmental disturbance since European settlement suggest that humans are now the most important mechanism for environmental change. Copyright

Humidification of the Arctic: Effects of more open ocean water on land temperatures and tundra productivity along continental and maritime bioclimate transects

NASA Astrophysics Data System (ADS)

Bhatt, U. S.; Walker, D. A.; Raynolds, M. K.; Epstein, H. E.

2017-12-01

Amplified Arctic warming linked to declining sea-ice extent led to generally enhanced productivity of the tundra biome during the period 1982-2008. After about 2002, coinciding with a recent precipitous decline in sea ice, large areas of the Arctic began showing reversals of previous positive productivity trends. To better understand these recent vegetation productivity declines and whether they are associated with differences in a general humidification of portions of the Arctic, we focus analysis on two transects with ground information: the more continental North America Arctic Transect (NAAT) and the more maritime Eurasia Arctic Transect (EAT). We compare ground information with satellite-derived trends in open water, summer terrestrial temperatures, and vegetation greenness and changes in continentality of the two transects, as indicated by the differences in the annual maximum and minimum mean monthly temperatures. Areas adjacent to perennial sea ice along in the northern parts of the NAAT exhibit climates with positive trends in summer warmth, but negative greening trends, possibly due to soil drying. Southern parts of the NAAT in the vicinity of more open water show positive greenness trends. Along the EAT, cooling midsummer conditions and reduced greenness appear to be caused by cloudier conditions, and possibly later snow melt during the period of maximum potential photosynthesis. Ground-based environmental and vegetation data indicate that biomass, particularly moss biomass is much greater along the more maritime EAT, indicating a buffering effect of the vegetation that will act to damp productivity as humidification of the Arctic proceeds. This multi-scale analysis is one step in the direction of understanding the drivers of tundra vegetation productivity in the Arctic.

A National Crop Progress Monitoring System Based on NASA Earth Science Results

NASA Astrophysics Data System (ADS)

Di, L.; Yu, G.; Zhang, B.; Deng, M.; Yang, Z.

2011-12-01

Crop progress is an important piece of information for food security and agricultural commodities. Timely monitoring and reporting are mandated for the operation of agricultural statistical agencies. Traditionally, the weekly reporting issued by the National Agricultural Statistics Service (NASS) of the United States Department of Agriculture (USDA) is based on reports from the knowledgeable state and county agricultural officials and farmers. The results are spatially coarse and subjective. In this project, a remote-sensing-supported crop progress monitoring system is being developed intensively using the data and derived products from NASA Earth Observing satellites. Moderate Resolution Imaging Spectroradiometer (MODIS) Level 3 product - MOD09 (Surface Reflectance) is used for deriving daily normalized vegetation index (NDVI), vegetation condition index (VCI), and mean vegetation condition index (MVCI). Ratio change to previous year and multiple year mean can be also produced on demand. The time-series vegetation condition indices are further combined with the NASS' remote-sensing-derived Cropland Data Layer (CDL) to estimate crop condition and progress crop by crop. To facilitate the operational requirement and increase the accessibility of data and products by different users, each component of the system has being developed and implemented following open specifications under the Web Service reference model of Open Geospatial Consortium Inc. Sensor observations and data are accessed through Web Coverage Service (WCS), Web Feature Service (WFS), or Sensor Observation Service (SOS) if available. Products are also served through such open-specification-compliant services. For rendering and presentation, Web Map Service (WMS) is used. A Web-service based system is set up and deployed at dss.csiss.gmu.edu/NDVIDownload. Further development will adopt crop growth models, feed the models with remotely sensed precipitation and soil moisture information, and incorporate the model results with vegetation-index time series for crop progress stage estimation.

What Attracts People to Visit Community Open Spaces? A Case Study of the Overseas Chinese Town Community in Shenzhen, China

PubMed Central

Chen, Yiyong; Liu, Tao; Xie, Xiaohuan; Marušić, Barbara Goličnik

2016-01-01

A well-designed open space that encourages outdoor activity and social communication is a community asset that could potentially contribute to the health of local residents and social harmony of the community. Numerous factors may influence the use of each single space and may result in a variety of visitors. Compared with previous studies that focused on accessibility, this study highlights the relationship between the utilization and characteristics of community open spaces in China. The Overseas Chinese Town community in Shenzhen is regarded as an example. The association between the number of visitors and space characteristics is examined with multivariate regression models. Results show that large areas with accessible lawns, well-maintained footpaths, seats, commercial facilities, and water landscapes are important characteristics that could increase the use of community open spaces. However, adding green vegetation, sculptures, and landscape accessories in open spaces has limited effects on increasing the outdoor activities of residents. Thus, to increase the use of community open spaces, landscape designers should focus more on creating user-oriented spaces with facilities that encourage active use than on improving ornamental vegetation and accessories. PMID:27367713

Patterns of glacial-interglacial vegetation and climate variability in eastern South Africa

NASA Astrophysics Data System (ADS)

Dupont, Lydie; Caley, Thibaut; Malaizé, Bruno; Giraudeau, Jacques

2010-05-01

Vegetation is an integrated part of the earth system and our understanding needs records of its glacial-interglacial variability. Although the data coverage for South Africa is slightly better than for some other parts of Africa, there are only very few records that allow us a glimpse of the vegetation history and development through one or more late Quaternary climate cycles. The existing evidence is fragmentary and in some cases contradictory. Marine sediments can offer here continuous sequences that cover large periods of time and provide a record of a signal that integrates rather large continental regions. Core MD96-2048 has been cored off the Limpopo River mouth at 26°10'S 34°01'E in 660 m water depth. This area is under the double influence of continental discharge and Agulhas current water advection. The sedimentation is slow and continuous. The upper 5 meter (down till 250 ka) have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests with an increase of dry deciduous forest and open woodland during interglacial optima. During glacials open mountainous shrubland extended. The pattern strongly suggests a shifting of altitudinal vegetation belts in the mountains primarily depending on temperature, although the decline of forested areas during glacial times might also be the effect of low atmospheric carbon dioxide concentrations. This pattern in eastern South Africa differs from that suggested for western South Africa, where extension of the winter rain climate seems likely, and corroborates findings of increased C4 vegetation during the Glacial of eastern South Africa. The spread of dry deciduous forest and open woodland suggests a hot and dry climate during interglacial optima. The vegetation and climate of eastern South Africa seems to follow a mid to high latitude rhythm, in which the glacial-interglacial contrast is more important than the precessional forced monsoon system of tropical Africa.

Carbon fluxes in a heterogeneous estuarine wetland in Northern Ohio. Comparing eddy covariance and chamber measurements

NASA Astrophysics Data System (ADS)

Rey Sanchez, C.; Morin, T. H.; Stefanik, K. C.; Wrighton, K. C.; Bohrer, G.

2016-12-01

Wetlands are important carbon dioxide (CO2) sinks but also the largest source of methane (CH4), a powerful greenhouse gas. Wetlands are often heterogeneous landscapes with highly diverse land covers and different paths of CH4 release and CO2 uptake. Understanding the ecosystem level greenhouse gas budget of a wetland involves understanding several carbon fluxes associated with each of the different land cover patches. We studied CO2 and CH4 fluxes from different land cover types at the Old Woman Creek (OWC) National Estuarine Research Reserve, at the Lake Erie shore in Northern Ohio. OWC is composed of four main types of land cover: open water, emergent cattail vegetation (Typha spp), floating vegetation (Nelimbo spp), and mud flats. CH4 and CO2 gas exchange was measured in each patch type using enclosed chambers monthly during the growing seasons of 2015 and 2016. During the same period of time, an eddy covariance tower was deployed in a representative section of the wetland to measure continuous site-level CO2 and CH4 fluxes. A footprint model was used to account for the relative contributions of each patch type to the flux measured by the tower. The chamber measurements were used to constrain the contributions of each patch within the flux tower footprint, and to correct the flux measurements to the whole-wetland total flux. We analyzed the spatial and temporal variability of methane and carbon dioxide and related this variation to some of the most important environmental drivers at the site. We used these data to analyze the implications of different arrangements of land cover types on the carbon balance and greenhouse-gas budget in wetlands.

Vegetation of the Elwha River estuary: Chapter 8 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

USGS Publications Warehouse

Shafroth, Patrick B.; Fuentes, Tracy L.; Pritekel, Cynthia; Beirne, Matthew M.; Beauchamp, Vanessa B.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

The Elwha River estuary supports one of the most diverse coastal wetland complexes yet described in the Salish Sea region, in terms of vegetation types and plant species richness. Using a combination of aerial imagery and vegetation plot sampling, we identified 6 primary vegetation types and 121 plant species in a 39.7 ha area. Most of the estuary is dominated by woody vegetation types, with mixed riparian forest being the most abundant (20 ha), followed by riparian shrub (6.3 ha) and willow-alder forest (3.9 ha). The shrub-emergent marsh transition vegetation type was fourth most abundant (2.2 ha), followed by minor amounts of dunegrass (1.75 ha) and emergent marsh (0.2 ha). This chapter documents the abundance, distribution, and floristics of these six vegetation types, including plant species richness, life form, species origin (native or introduced), and species wetland indicator status. These data will serve as a baseline to which future changes can be compared, following the impending removal of Glines Canyon and Elwha Dams upstream on the Elwha River. Dam removals may alter many of the processes, materials, and biotic interactions that influence the estuary plant communities, including hydrology, salinity, sediment and wood transport, nutrients, and plant-microbe interactions.

DISQOVER the Landcover - R based tools for quantitative vegetation reconstruction

NASA Astrophysics Data System (ADS)

Theuerkauf, Martin; Couwenberg, John; Kuparinen, Anna; Liebscher, Volkmar

2016-04-01

Quantitative methods have gained increasing attention in the field of vegetation reconstruction over the past decade. The DISQOVER package implements key tools in the R programming environment for statistical computing. This implementation has three main goals: 1) Provide a user-friendly, transparent, and open implementation of the methods 2) Provide full flexibility in all parameters (including the underlying pollen dispersal model) 3) Provide a sandbox for testing the sensitivity of the methods. We illustrate the possibilities of the package with tests of the REVEALS model and of the extended downscaling approach (EDA). REVEALS (Sugita 2007) is designed to translate pollen data from large lakes into regional vegetation composition. We applied REVEALSinR on pollen data from Lake Tiefer See (NE-Germany) and validated the results with historic landcover data. The results clearly show that REVEALS is sensitive to the underlying pollen dispersal model; REVEALS performs best when applied with the state of the art Lagrangian stochastic dispersal model. REVEALS applications with the conventional Gauss model can produce realistic results, but only if unrealistic pollen productivity estimates are used. The EDA (Theuerkauf et al. 2014) employs pollen data from many sites across a landscape to explore whether species distributions in the past were related to know stable patterns in the landscape, e.g. the distribution of soil types. The approach had so far only been implemented in simple settings with few taxa. Tests with EDAinR show that it produces sharp results in complex settings with many taxa as well. The DISQOVER package is open source software, available from disqover.uni-greifswald.de. This website can be used as a platform to discuss and improve quantitative methods in vegetation reconstruction. To introduce the tool we plan a short course in autumn of this year. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution (ICLEA; www.iclea.de) of the Helmholtz Association (Grant Number VH-VI-415) and is supported by Helmholtz infrastructure of the Terrestrial Environmental Observatory (TERENO) North-eastern Germany.

Four years of UAS Imagery Reveals Vegetation Change Due to Permafrost Thaw

NASA Astrophysics Data System (ADS)

DelGreco, J. L.; Herrick, C.; Varner, R. K.; McArthur, K. J.; McCalley, C. K.; Garnello, A.; Finnell, D.; Anderson, S. M.; Crill, P. M.; Palace, M. W.

2017-12-01

Warming trends in sub-arctic regions have resulted in thawing of permafrost which in turn induces change in vegetation across peatlands. Collapse of palsas (i.e. permafrost plateaus) has also been correlated to increases in methane (CH4) emissions to the atmosphere. Vegetation change provides new microenvironments that promote CH4 production and emission, specifically through plant interactions and structure. By quantifying the changes in vegetation at the landscape scale, we will be able to understand the impact of thaw on CH4 emissions in these complex and climate sensitive northern ecosystems. We combine field-based measurements of vegetation composition and high resolution Unmanned Aerial Systems (UAS) imagery to characterize vegetation change in a sub-arctic mire. At Stordalen Mire (1 km x 0.5 km), Abisko, Sweden, we flew a fixed-wing UAS in July of each year between 2014 and 2017. High precision GPS ground control points were used to georeference the imagery. Seventy-five randomized square-meter plots were measured for vegetation composition and individually classified into one of five cover types, each representing a different stage of permafrost degradation. With this training data, each year of imagery was classified by cover type. The developed cover type maps were also used to estimate CH4 emissions across the mire based on average flux CH4 rates from each cover type obtained from flux chamber measurements collected at the mire. This four year comparison of vegetation cover and methane emissions has indicated a rapid response to permafrost thaw and changes in emissions. Estimation of vegetation cover types is vital in our understanding of the evolution of northern peatlands and its future role in the global carbon cycle.

Classification and description of world formation types. Part. I (Introduction)

Treesearch

D. Faber-Langendoen; T. Keeler-Wolf; D. Meidinger; C. Josse; A. Weakley; D. Tart; G. Navarro; B. Hoagland; S. Ponomarenko; J.-P. Saucier; G. Fults; E. Helmer

2012-01-01

A vegetation-ecologic classification approach has been developed in which a combination of vegetation attributes (physiognomy, structure, and floristics) and their response to ecological and biogeographic factors are used as the basis for classifying vegetation types (Faber-Langendoen et al. 2012). This approach can help support international, national and subnational...

Gaseous polycyclic aromatic hydrocarbon concentrations are higher in urban forests than adjacent open areas during summer but not in winter--Exploratory study.

PubMed

Viippola, Viljami; Rantalainen, Anna-Lea; Yli-Pelkonen, Vesa; Tervo, Peatta; Setälä, Heikki

2016-01-01

While the potential of plants to uptake polycyclic aromatic hydrocarbons (PAHs) is widely acknowledged, empirical evidence of the effects of this process on local atmospheric PAH concentrations and human health is tenuous. We measured gaseous PAH concentrations using passive samplers in urban tree-covered areas and adjacent open, treeless areas in a near-road environment in Finland to gain information on the ability of urban vegetation to improve air quality. The ability of urban, mostly deciduous, vegetation to affect PAHs was season dependent: during summer, concentrations were significantly higher in tree-covered areas, while in the fall, concentrations in open areas exceeded those in tree-covered areas. During winter, concentrations in tree-covered areas were either lower or did not differ from those in open areas. Results of this study imply that the commonly believed notion that trees unequivocally improve air quality does not apply to PAHs studied here. Copyright © 2015 Elsevier Ltd. All rights reserved.

Perfluorinated Compounds in Greenhouse and Open Agricultural Producing Areas of Three Provinces of China: Levels, Sources and Risk Assessment

PubMed Central

Zhang, Yanwei; Tan, Dongfei; Geng, Yue; Wang, Lu; Peng, Yi; He, Zeying; Xu, Yaping; Liu, Xiaowei

2016-01-01

Field investigations on perfluoroalkyl acid (PFAA) levels in various environmental matrixes were reported, but there is still a lack of PFAA level data for agricultural environments, especially agricultural producing areas, so we collected soil, irrigation water and agricultural product samples from agricultural producing areas in the provinces of Liaoning, Shandong and Sichuan in China. The background pollution from instruments was removed and C4–C18 PFAAs were detected by LC-MS/MS. The concentrations of PFAAs in the top and deep layers of soil were compared, and the levels of PFAAs in different agricultural environments (greenhouses and open agriculture) were analyzed. We found the order of PFAA levels by province was Shandong > Liaoning > Sichuan. A descending trend of PFAA levels from top to deep soil and open to greenhouse agriculture was shown and perfluorobutanoic acid (PFBA) was considered as a marker for source analysis. Bean vegetables contribute highly to the overall PFAA load in vegetables. A significant correlation was shown between irrigation water and agricultural products. The EDI (estimated daily intake) from vegetables should be of concern in China. PMID:27973400

Which Food Security Determinants Predict Adequate Vegetable Consumption among Rural Western Australian Children?

PubMed Central

Godrich, Stephanie L.; Lo, Johnny; Davies, Christina R.; Darby, Jill; Devine, Amanda

2017-01-01

Improving the suboptimal vegetable consumption among the majority of Australian children is imperative in reducing chronic disease risk. The objective of this research was to determine whether there was a relationship between food security determinants (FSD) (i.e., food availability, access, and utilisation dimensions) and adequate vegetable consumption among children living in regional and remote Western Australia (WA). Caregiver-child dyads (n = 256) living in non-metropolitan/rural WA completed cross-sectional surveys that included questions on FSD, demographics and usual vegetable intake. A total of 187 dyads were included in analyses, which included descriptive and logistic regression analyses via IBM SPSS (version 23). A total of 13.4% of children in this sample had adequate vegetable intake. FSD that met inclusion criteria (p ≤ 0.20) for multivariable regression analyses included price; promotion; quality; location of food outlets; variety of vegetable types; financial resources; and transport to outlets. After adjustment for potential demographic confounders, the FSD that predicted adequate vegetable consumption were, variety of vegetable types consumed (p = 0.007), promotion (p = 0.017), location of food outlets (p = 0.027), and price (p = 0.043). Food retail outlets should ensure that adequate varieties of vegetable types (i.e., fresh, frozen, tinned) are available, vegetable messages should be promoted through food retail outlets and in community settings, towns should include a range of vegetable purchasing options, increase their reliance on a local food supply and increase transport options to enable affordable vegetable purchasing. PMID:28054955

Which Food Security Determinants Predict Adequate Vegetable Consumption among Rural Western Australian Children?

PubMed

Godrich, Stephanie L; Lo, Johnny; Davies, Christina R; Darby, Jill; Devine, Amanda

2017-01-03

Improving the suboptimal vegetable consumption among the majority of Australian children is imperative in reducing chronic disease risk. The objective of this research was to determine whether there was a relationship between food security determinants (FSD) (i.e., food availability, access, and utilisation dimensions) and adequate vegetable consumption among children living in regional and remote Western Australia (WA). Caregiver-child dyads ( n = 256) living in non-metropolitan/rural WA completed cross-sectional surveys that included questions on FSD, demographics and usual vegetable intake. A total of 187 dyads were included in analyses, which included descriptive and logistic regression analyses via IBM SPSS (version 23). A total of 13.4% of children in this sample had adequate vegetable intake. FSD that met inclusion criteria ( p ≤ 0.20) for multivariable regression analyses included price; promotion; quality; location of food outlets; variety of vegetable types; financial resources; and transport to outlets. After adjustment for potential demographic confounders, the FSD that predicted adequate vegetable consumption were, variety of vegetable types consumed ( p = 0.007), promotion ( p = 0.017), location of food outlets ( p = 0.027), and price ( p = 0.043). Food retail outlets should ensure that adequate varieties of vegetable types (i.e., fresh, frozen, tinned) are available, vegetable messages should be promoted through food retail outlets and in community settings, towns should include a range of vegetable purchasing options, increase their reliance on a local food supply and increase transport options to enable affordable vegetable purchasing.

Aspen community types of the Intermountain Region

Treesearch

Walter F. Mueggler

1988-01-01

This vegetation classification is based upon existing community structure and composition in the aspen-dominated forests of the Intermountain Region of the Forest Service. The 56 community types occur within eight tree-cover types. A diagnostic key using indicator species facilitates field identification of the community types. Vegetational composition, productivity,...

Meteorological factors associated with abundance of airborne fungal spores over natural vegetation

NASA Astrophysics Data System (ADS)

Crandall, Sharifa G.; Gilbert, Gregory S.

2017-08-01

The abundance of airborne fungal spores in agricultural and urban settings increases with greater air temperature, relative humidity, or precipitation. The same meteorological factors that affect temporal patterns in spore abundance in managed environments also vary spatially across natural habitats in association with differences in vegetation structure. Here we investigated how temporal and spatial variation in aerial spore abundance is affected by abiotic (weather) and biotic (vegetation) factors as a foundation for predicting how fungi may respond to changes in weather and land-use patterns. We measured the phenology of airborne fungal spores across a mosaic of naturally occurring vegetation types at different time scales to describe (1) how spore abundance changes over time, (2) which local meteorological variables are good predictors for airborne spore density, and (3) whether spore abundance differs across vegetation types. Using an air volumetric vacuum sampler, we collected spore samples at 3-h intervals over a 120-h period in a mixed-evergreen forest and coastal prairie to measure diurnal, nocturnal, and total airborne spore abundance across vegetation types. Spore samples were also collected at weekly and monthly intervals in mixed-evergreen forest, redwood forest, and maritime chaparral vegetation types from 12 field sites across two years. We found greater airborne spore densities during the wetter winter months compared to the drier summer months. Mean total spore abundance in the mixed-evergreen forest was twice than in the coastal prairie, but there were no significant differences in total airborne spore abundance among mixed-evergreen forest, redwood forest, and maritime chaparral vegetation types. Weekly and monthly peaks in airborne spore abundance corresponded with rain events and peaks in soil moisture. Overall, temporal patterns in meteorological factors were much more important in determining airborne fungal spore abundance than the vegetation type. This suggests that overall patterns of fungal spore dynamics may be predictable across heterogeneous landscapes based on local weather patterns.

Multi-discipline resource inventory of soils, vegetation and geology

NASA Technical Reports Server (NTRS)

Simonson, G. H. (Principal Investigator); Paine, D. P.; Lawrence, R. D.; Norgren, J. A.; Pyott, W. Y.; Herzog, J. H.; Murray, R. J.; Rogers, R.

1973-01-01

The author has identified the following significant results. Computer classification of natural vegetation, in the vicinity of Big Summit Prairie, Crook County, Oregon was carried out using MSS digital data. Impure training sets, representing eleven vegetation types plus water, were selected from within the area to be classified. Close correlations were visually observed between vegetation types mapped from the large scale photographs and the computer classification of the ERTS data (Frame 1021-18151, 13 August 1972).

Impact of understory vegetation on soil carbon and nitrogen dynamic in aerially seeded Pinus massoniana plantations.

PubMed

Pan, Ping; Zhao, Fang; Ning, Jinkui; Zhang, Ling; Ouyang, Xunzhi; Zang, Hao

2018-01-01

Understory vegetation plays a vital role in regulating soil carbon (C) and nitrogen (N) characteristics due to differences in plant functional traits. Different understory vegetation types have been reported following aerial seeding. While aerial seeding is common in areas with serious soil erosion, few studies have been conducted to investigate changes in soil C and N cycling as affected by understory vegetation in aerially seeded plantations. Here, we studied soil C and N characteristics under two naturally formed understory vegetation types (Dicranopteris and graminoid) in aerially seeded Pinus massoniana Lamb plantations. Across the two studied understory vegetation types, soil organic C was significantly correlated with all measured soil N variables, including total N, available N, microbial biomass N and water-soluble organic N, while microbial biomass C was correlated with all measured variables except soil organic C. Dicranopteris and graminoid differed in their effects on soil C and N process. Except water-soluble organic C, all the other C and N variables were higher in soils with graminoids. The higher levels of soil organic C, microbial biomass C, total N, available N, microbial biomass N and water-soluble organic N were consistent with the higher litter and root quality (C/N) of graminoid vegetation compared to Dicranopteris. Changes in soil C and N cycles might be impacted by understory vegetation types via differences in litter or root quality.

Impact of understory vegetation on soil carbon and nitrogen dynamic in aerially seeded Pinus massoniana plantations

PubMed Central

Pan, Ping; Zhao, Fang; Ning, Jinkui; Ouyang, Xunzhi; Zang, Hao

2018-01-01

Understory vegetation plays a vital role in regulating soil carbon (C) and nitrogen (N) characteristics due to differences in plant functional traits. Different understory vegetation types have been reported following aerial seeding. While aerial seeding is common in areas with serious soil erosion, few studies have been conducted to investigate changes in soil C and N cycling as affected by understory vegetation in aerially seeded plantations. Here, we studied soil C and N characteristics under two naturally formed understory vegetation types (Dicranopteris and graminoid) in aerially seeded Pinus massoniana Lamb plantations. Across the two studied understory vegetation types, soil organic C was significantly correlated with all measured soil N variables, including total N, available N, microbial biomass N and water-soluble organic N, while microbial biomass C was correlated with all measured variables except soil organic C. Dicranopteris and graminoid differed in their effects on soil C and N process. Except water-soluble organic C, all the other C and N variables were higher in soils with graminoids. The higher levels of soil organic C, microbial biomass C, total N, available N, microbial biomass N and water-soluble organic N were consistent with the higher litter and root quality (C/N) of graminoid vegetation compared to Dicranopteris. Changes in soil C and N cycles might be impacted by understory vegetation types via differences in litter or root quality. PMID:29377926

Prevalence and characterization of ESBL- and AmpC-producing Enterobacteriaceae on retail vegetables.

PubMed

van Hoek, Angela H A M; Veenman, Christiaan; van Overbeek, Wendy M; Lynch, Gretta; de Roda Husman, Ana Maria; Blaak, Hetty

2015-07-02

In total 1216 vegetables obtained from Dutch stores during 2012 and 2013 were analysed to determine the prevalence of 3rd-generation cephalosporin (3GC) resistant bacteria on soil-grown fresh produce possibly consumed raw. Vegetables grown conventionally and organically, from Dutch as well as foreign origin were compared. Included were the following vegetable types; blanched celery (n=192), bunched carrots (n=190), butterhead lettuce (n=137), chicory (n=96), endive (n=188), iceberg lettuce (n=193) and radish (n=120). Overall, 3GC-resistant Enterobacteriaceae were detected on 5.2% of vegetables. Based on primary habitat and mechanism of 3GC-resistance, these bacteria could be divided into four groups: ESBL-producing faecal species (Escherichia coli, Enterobacter spp.), AmpC-producing faecal species (Citrobacter freundii, Enterobacter spp.), ESBL-producing environmental species (Pantoea spp., Rahnella aquatilis, Serratia fonticola), and AmpC-producing environmental species (Cedecca spp., Hafnia alvei, Pantoea spp., Serratia plymuthica), which were detected on 0.8%, 1.2%, 2.6% and 0.4% of the vegetables analysed, respectively. Contamination with faecal 3GC-resistant bacteria was most frequently observed in root and bulb vegetables (average prevalence 4.4%), and less frequently in stem vegetables (prevalence 1.6%) and leafy greens (average prevalence 0.6%). In Dutch stores, only four of the included vegetable types (blanched celery, bunched carrots, endive, iceberg lettuce) were available in all four possible variants: Dutch/conventional, Dutch/organic, foreign/conventional, foreign/organic. With respect to these vegetable types, no statistically significant difference was observed in prevalence of 3GC-resistant Enterobacteriaceae between country of origin or cultivation type (5.2%, 5.7%, 5.7% and 3.3%, respectively). Vegetables consumed raw may be a source of dissemination of 3GC-resistant Enterobacteriaceae and their resistance genes to humans. The magnitude of the associated public health risk presumably depends on the types of bacteria that are ingested, i.e., faecal or environmental species, and may therefore be higher for root and bulb vegetables compared to leafy greens. Copyright © 2015 Elsevier B.V. All rights reserved.

Interpretations of vegetative change through 1989: The photopoints

Treesearch

G. E. Gruell; W. C. Schmidt; S. F. Arno; W. J. Reich

1999-01-01

The 1907 to 1911 logging operations and subsequent lack of surface fires dramatically changed the patterns of plant succession at Lick Creek. Large quantities of overstory pines were felled, creating sizable openings. Logs were skidded and slash was burned in piles (Koch 1998) locally scraping off or consuming surface vegetation, pine needle litter, and humus, and...

Planted Black Walnut Does Well on Cleared Forest Sites -- if Competition is Controlled

Treesearch

John E. Krajicek

1975-01-01

After seven growing seasons, survival of black walnut seedlings planted in cleared forest openings did not differ by competition control treatments. The trees grew somewhat larger where all competing vegetation was controlled but almost as large where only herbaceous competition was controlled. Controlling only woody vegetation was no better than no control of any...

Short term changes in hydroperiod after thin layer sediment placement on a New Jersey salt marsh and implications for design

NASA Astrophysics Data System (ADS)

Piercy, C.; Carrillo, C. C.; VanZomeren, C. M.; Berkowitz, J.; Chasten, M. A.; Golden, D.; Jahn, J.; Welp, T. L.; Yepsen, M.

2017-12-01

Over the winter of 2015-2016, the U.S. Army Corps of Engineers Philadelphia District partnered with New Jersey Department of Environmental Protection, The Nature Conservancy, Green Trust Alliance, Green Vest, and Princeton Hydro to implement a wetland thin layer placement on a salt marsh to the west of Avalon, New Jersey using dredged sediments removed from the Federal navigation channel in response to impacts from Hurricane Sandy. Prior to sediment placement, the marsh exhibited signs of degradation, including fragmentation of the marsh plain. The marsh is characterized by large, open water areas ( 1 m deep) fringed with overhanging banks and punctuated by small remnant ( 1-5 m) islands of intact marsh. The objective of the placement effort was to increase the elevation of degraded marsh areas to a level commensurate with the growth of low marsh vegetation dominated by Spartina alterniflora Loisel and to provide a small ( 5-15 cm) elevation boost to vegetated marsh areas surrounding the open water pools. We examine changes in inundation and tidal exchange resulting from the thin layer placement immediately after placement and a year later. Changes in sediment grain size and other factors are also considered. Coupling hydrologic measurements with observed vegetation recovery, we identify target elevations and sediment depths relative to mean sea level and mean high water consistent with rapid recovery in initially vegetated and open water areas.

Variations of deep soil moisture under different vegetation types and influencing factors in a watershed of the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Fang, Xuening; Zhao, Wenwu; Wang, Lixin; Feng, Qiang; Ding, Jingyi; Liu, Yuanxin; Zhang, Xiao

2016-08-01

Soil moisture in deep soil layers is a relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the variations in deep soil moisture and its influencing factors at a moderate watershed scale is important to ensure the sustainability of vegetation restoration efforts. In this study, we focus on analyzing the variations and factors that influence the deep soil moisture (DSM) in 80-500 cm soil layers based on a soil moisture survey of the Ansai watershed in Yan'an in Shanxi Province. Our results can be divided into four main findings. (1) At the watershed scale, higher variations in the DSM occurred at 120-140 and 480-500 cm in the vertical direction. At the comparable depths, the variation in the DSM under native vegetation was much lower than that in human-managed vegetation and introduced vegetation. (2) The DSM in native vegetation and human-managed vegetation was significantly higher than that in introduced vegetation, and different degrees of soil desiccation occurred under all the introduced vegetation types. Caragana korshinskii and black locust caused the most serious desiccation. (3) Taking the DSM conditions of native vegetation as a reference, the DSM in this watershed could be divided into three layers: (i) a rainfall transpiration layer (80-220 cm); (ii) a transition layer (220-400 cm); and (iii) a stable layer (400-500 cm). (4) The factors influencing DSM at the watershed scale varied with vegetation types. The main local controls of the DSM variations were the soil particle composition and mean annual rainfall; human agricultural management measures can alter the soil bulk density, which contributes to higher DSM in farmland and apple orchards. The plant growth conditions, planting density, and litter water holding capacity of introduced vegetation showed significant relationships with the DSM. The results of this study are of practical significance for vegetation restoration strategies, especially for the choice of vegetation types, planting zones, and proper human management measures.

Atmospheric pollutants in peri-urban forests of Quercus ilex: evidence of pollution abatement and threats for vegetation.

PubMed

García-Gómez, Héctor; Aguillaume, Laura; Izquieta-Rojano, Sheila; Valiño, Fernando; Àvila, Anna; Elustondo, David; Santamaría, Jesús M; Alastuey, Andrés; Calvete-Sogo, Héctor; González-Fernández, Ignacio; Alonso, Rocío

2016-04-01

Peri-urban vegetation is generally accepted as a significant remover of atmospheric pollutants, but it could also be threatened by these compounds, with origin in both urban and non-urban areas. To characterize the seasonal and geographical variation of pollutant concentrations and to improve the empirical understanding of the influence of Mediterranean broadleaf evergreen forests on air quality, four forests of Quercus ilex (three peri-urban and one remote) were monitored in different areas in Spain. Concentrations of nitrogen dioxide (NO2), ammonia (NH3), nitric acid (HNO3) and ozone (O3) were measured during 2 years in open areas and inside the forests and aerosols (PM10) were monitored in open areas during 1 year. Ozone was the only air pollutant expected to have direct phytotoxic effects on vegetation according to current thresholds for the protection of vegetation. The concentrations of N compounds were not high enough to directly affect vegetation but could be contributing through atmospheric N deposition to the eutrophization of these ecosystems. Peri-urban forests of Q. ilex showed a significant below-canopy reduction of gaseous concentrations (particularly NH3, with a mean reduction of 29-38%), which indicated the feasibility of these forests to provide an ecosystem service of air quality improvement. Well-designed monitoring programs are needed to further investigate air quality improvement by peri-urban ecosystems while assessing the threat that air pollution can pose to vegetation.

Emergent Macrophytes Support Zooplankton in a Shallow Tropical Lake: A Basis for Wetland Conservation

NASA Astrophysics Data System (ADS)

Gebrehiwot, Mesfin; Kifle, Demeke; Triest, Ludwig

2017-12-01

Understanding the biodiversity value of littoral zones of lakes is a priority for aquatic biodiversity conservation. However, less emphasis has been given to the littoral part of tropical African lakes, with many of the previous researches focusing only on the open water side. The aim of the present study was, therefore, to investigate the impact of the littoral zone of a shallow freshwater tropical lake (Ziway, Ethiopia), dominated by two emergent macrophytes, on zooplankton community structure. We hypothesized that the wetland vegetation serves as a preferred microhabitat for zooplankton communities. A lake with substantial coverage of emergent macrophytes was monitored monthly from January to August, 2016. The monitoring included the measurements of physical, chemical, and biological parameters. Sampling sites were selected to represent areas of the macrophyte vegetation ( Typha latifolia and Phragmites australis) and the open water part of the lake. Sites with macrophyte vegetation were found to be the home of more dense and diverse zooplankton community. However, during the period of high vegetation loss, the density of crustacean zooplankton showed significant reduction within the patches of macrophytes. From biodiversity conservation perspective, it was concluded that the preservation of such small areas of macrophytes covering the littoral zone of lakes could be as important as protecting the whole lake. However, the rapid degradation of wetland vegetation by human activities is a real threat to the lake ecosystem. In the not-too-far future, it could displace and evict riparian vegetation and the biota it supports.

Paleobiology of the Sand Beneath the Valders Diamicton at Valders, Wisconsin

NASA Astrophysics Data System (ADS)

Maher, Louis J.; Miller, Norton G.; Baker, Richard G.; Curry, B. Brandon; Mickelson, David M.

1998-03-01

Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty sand and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,200 14C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the red-brown diamicton of the Valders Member of the Kewaunee Formation. Fluctuations of abundance of Candona subtriangulata, Cytherissa lacustris,and three other species define four ostracode biozones in the lower 1.7 m, suggesting an open lake environment that oscillated in depth and proximity to glacial ice. Pollen is dominated by Piceaand Artemisia,but the low percentages of many other types of long-distance origin suggest that the terrestrial vegetation was open and far from the forest border. The upper part of the sediment, a massive sand deposited in either a shallow pond or a sluggish stream, contains a local concentration of plant macrofossils. The interpretation of a cold open environment is supported by the plant macrofossils of more than 20 species, dominated by those of open mineral soils ( Arenaria rubella, Cerastium alpinumtype, Silene acaulis, Sibbaldia procumbens, Dryas integrifolia, Vaccinium uliginosumvar. alpinum, Armeria maritima,etc.) that in North America occur largely in the tundra and open tundra-forest ecotone of northern Canada. Ice-wedge casts occur in the sand.

Portable platforms for setting rocket nets in open-water areas

USGS Publications Warehouse

Cox, R.R.; Afton, A.D.

1994-01-01

Rocket-netting of aquatic birds is generally done from permanent sites that are free of vegetation and debris to allow visibility and unobstructed projection of nets. We developed a technique for setting rocket nets on portable platforms to capture waterfowl in open-water habitats.

Integrating in-situ, Landsat, and MODIS data for mapping in Southern African savannas: experiences of LCCS-based land-cover mapping in the Kalahari in Namibia.

PubMed

Hüttich, Christian; Herold, Martin; Strohbach, Ben J; Dech, Stefan

2011-05-01

Integrated ecosystem assessment initiatives are important steps towards a global biodiversity observing system. Reliable earth observation data are key information for tracking biodiversity change on various scales. Regarding the establishment of standardized environmental observation systems, a key question is: What can be observed on each scale and how can land cover information be transferred? In this study, a land cover map from a dry semi-arid savanna ecosystem in Namibia was obtained based on the UN LCCS, in-situ data, and MODIS and Landsat satellite imagery. In situ botanical relevé samples were used as baseline data for the definition of a standardized LCCS legend. A standard LCCS code for savanna vegetation types is introduced. An object-oriented segmentation of Landsat imagery was used as intermediate stage for downscaling in-situ training data on a coarse MODIS resolution. MODIS time series metrics of the growing season 2004/2005 were used to classify Kalahari vegetation types using a tree-based ensemble classifier (Random Forest). The prevailing Kalahari vegetation types based on LCCS was open broadleaved deciduous shrubland with an herbaceous layer which differs from the class assignments of the global and regional land-cover maps. The separability analysis based on Bhattacharya distance measurements applied on two LCCS levels indicated a relationship of spectral mapping dependencies of annual MODIS time series features due to the thematic detail of the classification scheme. The analysis of LCCS classifiers showed an increased significance of life-form composition and soil conditions to the mapping accuracy. An overall accuracy of 92.48% was achieved. Woody plant associations proved to be most stable due to small omission and commission errors. The case study comprised a first suitability assessment of the LCCS classifier approach for a southern African savanna ecosystem.

Environmental controls on seasonal ecosystem evapotranspiration/potential evapotranspiration ratio as determined by the global eddy flux measurements

NASA Astrophysics Data System (ADS)

Liu, Chunwei; Sun, Ge; McNulty, Steven G.; Noormets, Asko; Fang, Yuan

2017-01-01

The evapotranspiration / potential evapotranspiration (AET / PET) ratio is traditionally termed as the crop coefficient (Kc) and has been generally used as ecosystem evaporative stress index. In the current hydrology literature, Kc has been widely used as a parameter to estimate crop water demand by water managers but has not been well examined for other types of ecosystems such as forests and other perennial vegetation. Understanding the seasonal dynamics of this variable for all ecosystems is important for projecting the ecohydrological responses to climate change and accurately quantifying water use at watershed to global scales. This study aimed at deriving monthly Kc for multiple vegetation cover types and understanding its environmental controls by analyzing the accumulated global eddy flux (FLUXNET) data. We examined monthly Kc data for seven vegetation covers, including open shrubland (OS), cropland (CRO), grassland (GRA), deciduous broad leaf forest (DBF), evergreen needle leaf forest (ENF), evergreen broad leaf forest (EBF), and mixed forest (MF), across 81 sites. We found that, except for evergreen forests (EBF and ENF), Kc values had large seasonal variation across all land covers. The spatial variability of Kc was well explained by latitude, suggesting site factors are a major control on Kc. Seasonally, Kc increased significantly with precipitation in the summer months, except in EBF. Moreover, leaf area index (LAI) significantly influenced monthly Kc in all land covers, except in EBF. During the peak growing season, forests had the highest Kc values, while croplands (CRO) had the lowest. We developed a series of multivariate linear monthly regression models for Kc by land cover type and season using LAI, site latitude, and monthly precipitation as independent variables. The Kc models are useful for understanding water stress in different ecosystems under climate change and variability as well as for estimating seasonal ET for large areas with mixed land covers.

Laboratory measurements of trace gas emissions from biomass burning of fuel types from the southeastern and southwestern United States

NASA Astrophysics Data System (ADS)

Burling, I. R.; Yokelson, R. J.; Griffith, D. W. T.; Johnson, T. J.; Veres, P.; Roberts, J. M.; Warneke, C.; Urbanski, S. P.; Reardon, J.; Weise, D. R.; Hao, W. M.; de Gouw, J.

2010-11-01

Vegetation commonly managed by prescribed burning was collected from five southeastern and southwestern US military bases and burned under controlled conditions at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The smoke emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared (OP-FTIR) spectrometer for measurement of gas-phase species. The OP-FTIR detected and quantified 19 gas-phase species in these fires: CO2, CO, CH4, C2H2, C2H4, C3H6, HCHO, HCOOH, CH3OH, CH3COOH, furan, H2O, NO, NO2, HONO, NH3, HCN, HCl, and SO2. Emission factors for these species are presented for each vegetation type burned. Gas-phase nitrous acid (HONO), an important OH precursor, was detected in the smoke from all fires. The HONO emission factors ranged from 0.15 to 0.60 g kg-1 and were higher for the southeastern fuels. The fire-integrated molar emission ratios of HONO (relative to NOx) ranged from approximately 0.03 to 0.20, with higher values also observed for the southeastern fuels. The majority of non-methane organic compound (NMOC) emissions detected by OP-FTIR were oxygenated volatile organic compounds (OVOCs) with the total identified OVOC emissions constituting 61 ± 12% of the total measured NMOC on a molar basis. These OVOC may undergo photolysis or further oxidation contributing to ozone formation. Elevated amounts of gas-phase HCl and SO2 were also detected during flaming combustion, with the amounts varying greatly depending on location and vegetation type. The fuels with the highest HCl emission factors were all located in the coastal regions, although HCl was also observed from fuels farther inland. Emission factors for HCl were generally higher for the southwestern fuels, particularly those found in the chaparral biome in the coastal regions of California.

Laboratory measurements of trace gas emissions from biomass burning of fuel types from the Southeastern and Southwestern United States

NASA Astrophysics Data System (ADS)

Burling, I. R.; Yokelson, R. J.; Griffith, D. W. T.; Johnson, T. J.; Veres, P.; Roberts, J. M.; Warneke, C.; Urbanski, S. P.; Reardon, J.; Weise, D. R.; Hao, W. M.; de Gouw, J.

2010-07-01

Vegetation commonly managed by prescribed burning was collected from five southeastern and southwestern US military bases and burned under controlled conditions at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The smoke emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared (OP-FTIR) spectrometer for measurement of gas-phase species. The OP-FTIR detected and quantified 19 gas-phase species in these fires: CO2, CO, CH4, C2H2, C2H4, C3H6, HCHO, HCOOH, CH3OH, CH3COOH, furan, H2O, NO, NO2, HONO, NH3, HCN, HCl, and SO2. Emission factors for these species are presented for each vegetation type burned. Gas-phase nitrous acid (HONO), an important OH precursor, was detected in the smoke from all fires. The HONO emission factors ranged from 0.15 to 0.60 g kg-1 and were higher for the southeastern fuels. The fire-integrated molar emission ratios of HONO (relative to NOx) ranged from approximately 0.03 to 0.20, with higher values also observed for the southeastern fuels. The majority of non-methane organic compound (NMOC) emissions detected by OP-FTIR were oxygenated volatile organic compounds (OVOCs) with the total identified OVOC emissions constituting 61±12% of the total measured NMOC on a molar basis. These OVOC may undergo photolysis or further oxidation contributing to ozone formation. Elevated amounts of gas-phase HCl and SO2 were also detected during flaming combustion, with the amounts varying greatly depending on location and vegetation type. The fuels with the highest HCl emission factors were all located in the coastal regions, although HCl was also observed from fuels farther inland. Emission factors for HCl were generally higher for the southwestern fuels, particularly those found in the chaparral biome in the coastal regions of California.

Environmental controls on seasonal ecosystem evapotranspiration/potential evapotranspiration ratio as determined by the global eddy flux measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chunwei; Sun, Ge; McNulty, Steven G.

The evapotranspiration / potential evapotranspiration (AET / PET) ratio is traditionally termed as the crop coefficient ( K c) and has been generally used as ecosystem evaporative stress index. In the current hydrology literature, K c has been widely used as a parameter to estimate crop water demand by water managers but has not been well examined for other types of ecosystems such as forests and other perennial vegetation. Understanding the seasonal dynamics of this variable for all ecosystems is important for projecting the ecohydrological responses to climate change and accurately quantifying water use at watershed to global scales. Thismore » study aimed at deriving monthly K c for multiple vegetation cover types and understanding its environmental controls by analyzing the accumulated global eddy flux (FLUXNET) data. We examined monthly K c data for seven vegetation covers, including open shrubland (OS), cropland (CRO), grassland (GRA), deciduous broad leaf forest (DBF), evergreen needle leaf forest (ENF), evergreen broad leaf forest (EBF), and mixed forest (MF), across 81 sites. We found that, except for evergreen forests (EBF and ENF), K c values had large seasonal variation across all land covers. The spatial variability of K c was well explained by latitude, suggesting site factors are a major control on K c. Seasonally, K c increased significantly with precipitation in the summer months, except in EBF. Moreover, leaf area index (LAI) significantly influenced monthly K c in all land covers, except in EBF. During the peak growing season, forests had the highest K c values, while croplands (CRO) had the lowest. We developed a series of multivariate linear monthly regression models for K c by land cover type and season using LAI, site latitude, and monthly precipitation as independent variables. Here, the K c models are useful for understanding water stress in different ecosystems under climate change and variability as well as for estimating seasonal ET for large areas with mixed land covers.« less

Environmental controls on seasonal ecosystem evapotranspiration/potential evapotranspiration ratio as determined by the global eddy flux measurements

DOE PAGES

Liu, Chunwei; Sun, Ge; McNulty, Steven G.; ...

2017-01-18

The evapotranspiration / potential evapotranspiration (AET / PET) ratio is traditionally termed as the crop coefficient ( K c) and has been generally used as ecosystem evaporative stress index. In the current hydrology literature, K c has been widely used as a parameter to estimate crop water demand by water managers but has not been well examined for other types of ecosystems such as forests and other perennial vegetation. Understanding the seasonal dynamics of this variable for all ecosystems is important for projecting the ecohydrological responses to climate change and accurately quantifying water use at watershed to global scales. Thismore » study aimed at deriving monthly K c for multiple vegetation cover types and understanding its environmental controls by analyzing the accumulated global eddy flux (FLUXNET) data. We examined monthly K c data for seven vegetation covers, including open shrubland (OS), cropland (CRO), grassland (GRA), deciduous broad leaf forest (DBF), evergreen needle leaf forest (ENF), evergreen broad leaf forest (EBF), and mixed forest (MF), across 81 sites. We found that, except for evergreen forests (EBF and ENF), K c values had large seasonal variation across all land covers. The spatial variability of K c was well explained by latitude, suggesting site factors are a major control on K c. Seasonally, K c increased significantly with precipitation in the summer months, except in EBF. Moreover, leaf area index (LAI) significantly influenced monthly K c in all land covers, except in EBF. During the peak growing season, forests had the highest K c values, while croplands (CRO) had the lowest. We developed a series of multivariate linear monthly regression models for K c by land cover type and season using LAI, site latitude, and monthly precipitation as independent variables. Here, the K c models are useful for understanding water stress in different ecosystems under climate change and variability as well as for estimating seasonal ET for large areas with mixed land covers.« less

A New Approach to Monitoring Coastal Marshes for Persistent Flooding

NASA Astrophysics Data System (ADS)

Kalcic, M. T.; Underwood, L. W.; Fletcher, R. M.

2012-12-01

Many areas in coastal Louisiana are below sea level and protected from flooding by a system of natural and man-made levees. Flooding is common when the levees are overtopped by storm surge or rising rivers. Many levees in this region are further stressed by erosion and subsidence. The floodwaters can become constricted by levees and trapped, causing prolonged inundation. Vegetative communities in coastal regions, from fresh swamp forest to saline marsh, can be negatively affected by inundation and changes in salinity. As saltwater persists, it can have a toxic effect upon marsh vegetation causing die off and conversion to open water types, destroying valuable species habitats. The length of time the water persists and the average annual salinity are important variables in modeling habitat switching (cover type change). Marsh type habitat switching affects fish, shellfish, and wildlife inhabitants, and can affect the regional ecosystem and economy. There are numerous restoration and revitalization projects underway in the coastal region, and their effects on the entire ecosystem need to be understood. For these reasons, monitoring persistent saltwater intrusion and inundation is important. For this study, persistent flooding in Louisiana coastal marshes was mapped using MODIS (Moderate Resolution Imaging Spectroradiometer) time series of a Normalized Difference Water Index (NDWI). The time series data were derived for 2000 through 2009, including flooding due to Hurricane Rita in 2005 and Hurricane Ike in 2008. Using the NDWI, duration and extent of flooding can be inferred. The Time Series Product Tool (TSPT), developed at NASA SSC, is a suite of software developed in MATLAB® that enables improved-quality time series images to be computed using advanced temporal processing techniques. This software has been used to compute time series for monitoring temporal changes in environmental phenomena, (e.g. NDVI times series from MODIS), and was modified and used to compute the NDWI indices and also the Normalized Difference Soil Index (NDSI). Coastwide Reference Monitoring System (CRMS) water levels from various hydrologic monitoring stations and aerial photography were used to optimize thresholds for MODIS-derived time series of NDWI and to validate resulting flood maps. In most of the profiles produced for post-hurricane assessment, the increase in the NDWI index (from storm surge) is accompanied by a decrease in the vegetation index (NDVI) and then a period of declining water. The NDSI index represents non-green or dead vegetation and increases after the hurricane's destruction of the marsh vegetation. Behavior of these indices over time is indicative of which areas remain flooded, which areas recover to their former levels of vegetative vigor, and which areas are stressed or in transition. Tracking these indices over time shows the recovery rate of vegetation and the relative behavior to inundation persistence. The results from this study demonstrated that identification of persistent marsh flooding, utilizing the tools developed in this study, provided an approximate 70-80 percent accuracy rate when compared to the actual days flooded at the CRMS stations.

A New Approach to Monitoring Coastal Marshes for Persistent Flooding

NASA Technical Reports Server (NTRS)

Kalcic, M. T.; Undersood, Lauren W.; Fletcher, Rose

2012-01-01

Many areas in coastal Louisiana are below sea level and protected from flooding by a system of natural and man-made levees. Flooding is common when the levees are overtopped by storm surge or rising rivers. Many levees in this region are further stressed by erosion and subsidence. The floodwaters can become constricted by levees and trapped, causing prolonged inundation. Vegetative communities in coastal regions, from fresh swamp forest to saline marsh, can be negatively affected by inundation and changes in salinity. As saltwater persists, it can have a toxic effect upon marsh vegetation causing die off and conversion to open water types, destroying valuable species habitats. The length of time the water persists and the average annual salinity are important variables in modeling habitat switching (cover type change). Marsh type habitat switching affects fish, shellfish, and wildlife inhabitants, and can affect the regional ecosystem and economy. There are numerous restoration and revitalization projects underway in the coastal region, and their effects on the entire ecosystem need to be understood. For these reasons, monitoring persistent saltwater intrusion and inundation is important. For this study, persistent flooding in Louisiana coastal marshes was mapped using MODIS (Moderate Resolution Imaging Spectroradiometer) time series of a Normalized Difference Water Index (NDWI). The time series data were derived for 2000 through 2009, including flooding due to Hurricane Rita in 2005 and Hurricane Ike in 2008. Using the NDWI, duration and extent of flooding can be inferred. The Time Series Product Tool (TSPT), developed at NASA SSC, is a suite of software developed in MATLAB(R) that enables improved-quality time series images to be computed using advanced temporal processing techniques. This software has been used to compute time series for monitoring temporal changes in environmental phenomena, (e.g. NDVI times series from MODIS), and was modified and used to compute the NDWI indices and also the Normalized Difference Soil Index (NDSI). Coastwide Reference Monitoring System (CRMS) water levels from various hydrologic monitoring stations and aerial photography were used to optimize thresholds for MODIS-derived time series of NDWI and to validate resulting flood maps. In most of the profiles produced for post-hurricane assessment, the increase in the NDWI index (from storm surge) is accompanied by a decrease in the vegetation index (NDVI) and then a period of declining water. The NDSI index represents non-green or dead vegetation and increases after the hurricane s destruction of the marsh vegetation. Behavior of these indices over time is indicative of which areas remain flooded, which areas recover to their former levels of vegetative vigor, and which areas are stressed or in transition. Tracking these indices over time shows the recovery rate of vegetation and the relative behavior to inundation persistence. The results from this study demonstrated that identification of persistent marsh flooding, utilizing the tools developed in this study, provided an approximate 70-80 percent accuracy rate when compared to the actual days flooded at the CRMS stations.

Microwave model prediction and verifications for vegetated terrain

NASA Technical Reports Server (NTRS)

Fung, A. K.

1985-01-01

To understand the scattering properties of a deciduous and a coniferous type vegetation scattering models were developed assuming either a disc type leaf or a needle type leaf. The major effort is to calculate the corresponding scattering phase functions and then each of the functions is used in a radiative transfer formulation to compute the scattering intensity and consequently the scattering coefficient. The radiative transfer formulation takes into account the irregular ground surface by including the rough soil surface in the boundary condition. Thus, the scattering model accounts for volume scattering inside the vegetation layer, the surface scattering from the ground and the interaction between scattering from the soil surface and the vegetation volume. The contribution to backscattering by each of the three scattering mechanisms is illustrated along with the effects of each layer or surface parameter. The major difference between the two types of vegetation is that when the incident wavelength is comparable to the size of the leaf there is a peak appearing in the mid angular region of the backscattering curve for the disc type leaf whereas it is a dip in the same region for a needle type leaf.

Spatial distribution of soil properties on a landslide in Taiwan: effects of movement types and vegetation

NASA Astrophysics Data System (ADS)

Lee, Pei-Chen; Cheng, Chih-Hsin

2017-04-01

Landslides are critical natural disturbances in tropical and temperate areas and exert immense impacts on forest ecosystems and soil properties. The impacts of landslides on soil properties not only vary with their movement type, scale, or location but also have great spatial variation inside landslide. In this study, the effects of movement type (erosion and deposition) and succeeding vegetation on soil properties inside a landslide scar were evaluated. The study site was located in Chiufenernshan, central Taiwan. The landslide was triggered by the Chi-Chi Earthquake (Ritch magnitude 7.3) in 1999. A huge amount of waste debris (30 million m3) was moved along the sliding slope (with a tipping degree at 26o) and deposited in the lower parts. Total area size of landslide scar was 200 ha and about 30 - 50 m depth waste material was eroded/deposited in the upper/lower scar areas. After 17 years, the succeeding vegetation varied inside landslide scar. The erosion areas were covered with grass (Miscanthus floridulus) or left barren in some slopes. In contrast, a secondary forest, dominated with Trema orientalis, Lithocarpus konishii, Mallotus paniculatus, and Smilax bracteata, developed in the deposition areas. We collected soil samples in different landscape areas including (i) erosion areas without vegetation, (ii) erosion areas with grass vegetation, (iii) deposition areas, and (iv) adjacent undisturbed areas. Our results indicated that the erosion areas had higher bulk density, rock fragment and pH value, but less soil organic carbon, total nitrogen, total phosphorus and N-mineralization rate than both deposition and adjacent undisturbed areas. The soil properties without vegetation even showed the extreme end compared to the soils with grass vegetation. Soils at the deposition zone had similar rock fragment, bulk density, soil pH, soil organic carbon and N-mineralization rate values to the undisturbed site (p > 0.05). We speculate that movement types could determine the initial establishment of vegetation types and then influence soil properties under vegetation succession. Therefore, both waste movement types and vegetation and their interactions play important roles on soil properties.

Vegetation of prairie potholes, North Dakota, in relation to quality of water and other environmental factors

USGS Publications Warehouse

Stewart, R.E.; Kantrud, H.A.

1972-01-01

Measurements of specific conductance provide an adequate indication of the average salinity of surface waters in natural ponds and lakes of the northern .prairie region. Yearly and seasonal variations in specific conductance were much greater in brackish and subsaline wetlands than in fresh-water areas. The principal vegetational types. Land-use practices of varying brackish to saline wetlands were sulfates and chlorides of sodium and magnesium. In less saline waters, carbonate and bicarbonate salts of calcium and potassium were of greater importance, but as salinity increased, the proportion of these compounds decreased rapidly.A major environmental factor controlling the establishment of marsh and aquatic vegetation is the permanence of surface water. Permanence is a measure of the extent to which surface water persists at a given site. Varying degrees of water permanence during the growing season led to the establishment of distinct vegetational types, which were differentiated primarily on the 'basis of community structure or life form of the dominant vegetation.Salinity of surface waters was closely correlated with differences in species composition of plant communities found in the principal vegetational types. Land-use practices of varying degrees of intensity also had a secondary influence on species composition. Since an unstable water chemistry is characteristic of most prairie ponds and lakes, it is more reliable to use the plant communities as indicators of average salinity than to use single measurements of specific conductance.Characteristic species of wetland vegetational types occupied the central deeper parts of pond and lake basins or occurred as concentric peripheral bands. The wetland vegetational types are wetland low-prairie, wet-meadow, shallow-marsh emergent, deep-marsh emergent, fen emergent, submerged and floating, natural drawdown, cropland drawdown, and cropland tillage vegetation. Combinations of species (plant associations) within these vegetational types were placed in one of six salinity categories designated as fresh, slightly brackish, moderately brackish, brackish, subsaline, and saline. Salt tolerance apparently varied greatly among the various marsh and aquatic plants since the num'ber of species represented in moderately brackish to saline communities decreased markedly with increased salinity of the surface water environment.

Plant biomass in the Tanana River Basin, Alaska.

Treesearch

Bert R. Mead

1995-01-01

Vegetation biomass tables are presented for the Tanana River basin. Average biomass for each species of tree, shrub, grass, forb, lichen, and moss in the 13 forest and 30 nonforest vegetation types is shown. These data combined with area estimates for each vegetation type provide a tool for estimating habitat carrying capacity for many wildlife species. Tree biomass is...

Nutrients and biomass spatial patterns in alpine tundra ecosystem on Changbai Mountains, Northeast China.

PubMed

Wu, Gang; Jiang, Ping; Wei, Jing; Shao, Hongbo

2007-11-15

Biomass and nutrients were investigated in 2003, 2004 and 2005 growing seasons by using a chronosequence of five vegetation types in alpine tundra on Changbai Mountains. The objective of this study was to test whether nutrients at biointerfaces were significant differences among five vegetation types. The biomass and elevation are highly related (biomass=-237.3ln(elevation)+494.36; R(2)=0.8092; p<0.05). There were no significant differences in phosphorus (P) and sulphur (S) concentrations of roots, stems and leaves among five vegetation types while there are significant differences in nitrogen (N) and P stocks of roots, stems and leaves and in S stock of stems and leaves among typical alpine tundra vegetation (TA), meadow alpine tundra vegetation (MA), and swamp alpine tundra vegetation (SA) (p<0.05). Vegetation nutrients stock is averagely 72.46kg hm(-2), and N, P, S stocks are 48.55, 10.33 and 13.61kg hm(-2), respectively. Soil N and S concentrations in MA are significantly higher than those in other four soil types. P is higher in SA (p<0.05). Soil nutrients stock (0-20cm) is averagely 39.59t hm(-2), and N, P, S stocks are 23.74, 5.86 and 9.99t hm(-2), respectively.

Relationship of young-of-the-year northern pike to aquatic vegetation types in backwaters of the upper Mississippi River

USGS Publications Warehouse

Holland, L.E.; Huston, M.L.

1984-01-01

The association of young-of-the-year northern pike (Esox lucius) with different aquatic plant types (e.g., submerged, emergent, floating) was studied to evaluate the impacts of a potential loss of backwaters on available fish nursery habitats in the upper Mississippi River. Eight biweekly collections were made at each of six representative lentic habitats in Navigation Pool 7. In the spring, average catches of northern pike from areas with submerged vegetation were nearly three times greater than from areas with emergent vegetation, and more than 10 times greater than from an area with no vegetation. This pattern was consistent until late summer, when the young became more common in the more highly oxygenated, less heavily vegetated waters. Food and growth were examined as possible indicators for the selection of areas with submerged vegetation over other habitats. Food varied among fish in the different vegetation types; however, no significant patterns of improved growth or condition were apparent. Young northern pike apparently were successful, opportunistic feeders. Although preference for habitats with submerged vegetation was seemingly not related to food, the overall production of young was clearly best in these habitats.

Hydrological and Vegetation Variability from Mediterranean Leaf Wax Biomarkers Before and After the Rise of East African C4 Grasslands

NASA Astrophysics Data System (ADS)

Meyers, C.; deMenocal, P. B.; Tierney, J. E.; Polissar, P. J.

2012-12-01

Terrestrial and marine paleoclimate records and changes in African fossil mammal taxa indicate that a transition towards more open, C4-dominated grasslands occurred in East Africa near 2 Ma. In contrast, the Mediterranean sapropel record documents pervasive precession-paced wet/dry cycles in the strength of the African monsoon and Nile runoff since at least the late Miocene. This study investigates whether the East African vegetation shift after 2 Ma was accompanied by a change in the monsoonal wet/dry cycle response to orbital precession forcing. We sampled eastern Mediterranean ODP Site 967 at 2-3 ka resolution in two 200 kyr intervals near 3.0 and 1.7 Ma. Nearly identical orbital configurations in these intervals allow us to compare mean conditions and orbital-paced variations before and after the 2 Ma transition. We used leaf wax biomarker concentrations and δD and δ13C compositions as proxies for monsoonal strength and vegetation type, and the δ18O composition of G. ruber as a proxy for Nile River runoff. Leaf wax biomarker concentrations varied over three orders of magnitude, with much higher concentrations in sapropels. During sapropel intervals, large-amplitude negative excursions occur in δDwax, δ13Cwax, and δ18Oruber, corresponding to a strengthened monsoon and less abundant C4 plants. Carbonate-rich intervals have positive isotope excursions indicating a weakened monsoon and more abundant C4 plants. The mean and variance of δDwax and δ13Cwax values are not significantly different between the 3.0 Ma and 1.7 Ma intervals indicating Northern Africa did not experience the vegetation and climate shifts observed in East Africa. While surprising, our finding suggests that the average monsoonal response to precession forcing, and corresponding vegetation variability, did not substantially change across the 2 Ma transition. This implies that North and East Africa exhibited different climate and vegetation behavior since 3 Ma.

Vulnerability and Resilience of Temperate Forest Landscapes to Broad-Scale Deforestation in Response to Changing Fire Regimes and Altered Post-Fire Vegetation Dynamics

NASA Astrophysics Data System (ADS)

Tepley, A. J.; Veblen, T. T.; Perry, G.; Anderson-Teixeira, K. J.

2015-12-01

In the face of on-going climatic warming and land-use change, there is growing concern that temperate forest landscapes could be near a tipping point where relatively small changes to the fire regime or altered post-fire vegetation dynamics could lead to extensive conversion to shrublands or savannas. To evaluate vulnerability and resilience to such conversion, we develop a simple model based on three factors we hypothesize to be key in predicting temperate forest responses to changing fire regimes: (1) the hazard rate (i.e., the probability of burning in the next year given the time since the last fire) in closed-canopy forests, (2) the hazard rate for recently-burned, open-canopy vegetation, and (3) the time to redevelop canopy closure following fire. We generate a response surface representing the proportions of the landscape potentially supporting closed-canopy forest and non-forest vegetation under nearly all combinations of these three factors. We then place real landscapes on this response surface to assess the type and magnitude of changes to the fire regime that would drive extensive forest loss. We show that the deforestation of much of New Zealand that followed initial human colonization and the introduction of a new ignition source ca. 750 years ago was essentially inevitable due to the slow rate of forest recovery after fire and the high flammability of post-fire vegetation. In North America's Pacific Northwest, by contrast, a predominantly forested landscape persisted despite two periods of widespread burning in the recent past due in large part to faster post-fire forest recovery and less pronounced differences in flammability between forests and the post-fire vegetation. We also assess the factors that could drive extensive deforestation in other regions to identify where management could reduce this potential and to guide field and modeling work to better understand the responses and ecological feedbacks to changing fire regimes.

Vegetation index anomaly response to varying lengths of drought across vegetation and climatic gradients in Hawaii

NASA Astrophysics Data System (ADS)

Lucas, M.; Miura, T.; Trauernicht, C.; Frazier, A. G.

2017-12-01

A drought which results in prolonged and extended deficit in naturally available water supply and creates multiple stresses across ecosystems is classified as an ecological drought. Detecting and understanding the dynamics and response of such droughts in tropical systems, specifically across various vegetation and climatic gradients is fairly undetermined, yet increasingly important for better understandings of the ecological effects of drought. To understanding the link between what lengths and intensities of known meteorological drought triggers detectable ecological vegetation responses, a landscape scale regression analysis evaluating the response (slope) and relationship strength (R-squared) of several cumulative SPI (standard precipitation index) lengths(1, 3, 6, 12, 18, 24, 36, 48, and 60 month), to various satellite derived monthly vegetation indices anomalies (NDVI, EVI, EVI2, and LSWI) was performed across a matrix of dominant vegetation covers (grassland, shrubland, and forest) and climatic moisture zones (arid, dry, mesic, and wet). The nine different SPI lags across these climactic and vegetation gradients was suggest that stronger relationships and steeper slopes were found in dryer climates (across all vegetation covers) and finer vegetation types (across all moisture zones). Overall NDVI, EVI and EVI2 showed the best utility in these dryer climatic zones across all vegetation types. Within arid and dry areas "best" fits showed increasing lengths of cumulative SPI were with increasing vegetation coarseness respectively. Overall these findings suggest that rainfall driven drought may have a stronger impact on the ecological condition of vegetation in water limited systems with finer vegetation types ecologically responding more rapidly to meteorological drought events than coarser woody vegetation systems. These results suggest that previously and newly documented trends of decreasing rainfall and increasing drought in Hawaiian drylands may have drastic and lasting impacts on these unique ecosystems.

Early Pliocene vegetation distribution in Europe

NASA Astrophysics Data System (ADS)

Popescu, S.; Warny, S.; Suc, J.

2010-12-01

The Early Pliocene corresponds to a global warm climate documented by marine & terrestrial records. Reconstruction of climatic parameters, based on terrestrial proxies, indicate at European mid-latitudes a MAT higher of about 1-5°C than today and MAP higher of about 400-1000 mm. This global warm situation was interrupted between 4.7 - 4.5 Ma by a cooling event related to small fluctuations of the Antarctic ice-sheet that modify the floristic assemblages. according to pollen recors, the Northern Mediterranean area is characterized by dominance of arboreal pollen, suggesting a dense forest cover, on contrary to the Southern Mediterranean where herbs were prevalent, signifying a widespread development of open vegetation during the early Pliocene. Such a contrast in landscape between the North and the South of the Mediterranean is to be related to the latitudinal gradient in humidity. In the North Mediterranean area, the vegetation organization was also closely linked to the relief. Coastal plains were inhabited by Taxodiaceae swamps replaced in some places by marshes. With respect to the geographic position, several plant ecosystems can distinguished: (1) salt marshes, along the Atlantic coastline (zone A); (2) marshes mostly made of Cyperaceae evidenced on the Mediterranean coastline. Such juxtaposed assemblages resemble the modern vegetation of the Mississippi Delta and Florida. Peculiar vegetation assemblages characterize the Mediterranean coastal plains. In the southeastern Mediterranean region (Zone B), the open vegetation was composed by herbs including subdesertic elements. Mediterranean xerophytes are only numerically represented in the area of Tarragona and Sicily, their assemblage resemble the modern thermo-mediterranean formation. Close to the mountains (Zone C) vegetation is organized according to an altitudinal gradient. The low altitude vegetation was composed by Taxodiaceae (Sequoia) while Cathaya and Cedrus dominated the mid-altitude belt. Abies and Picea developed in higher altitude. The Eastern Europe vegetation (zone D) was characterized by coexistent warm-temperate forests and open ecosystems. Some megathermic and mega-mesothermic elements were persisting. Mediterranean xerophytes were indentified in few amounts in the Eastern Europe, showing a slight increase according to the latitudinal gradient. Site 380A (Black Sea) provides relatively high percentages of Artemisia growing in Anatolia, which increased again during the cooler periods. Anatolia probably represents the origin of the repeated steppe expansions which occurred in Europe at each glacial phase. Finally, the Nile region (zone E) documents the presence of savannah (composed mainly by Poaceae and Cyperaceae) including some subdesertic taxa. Nile riparian forests preserved several tropical-subtropical elements.

Terrestrial vegetation redistribution and carbon balance under climate change

PubMed Central

Lucht, Wolfgang; Schaphoff, Sibyll; Erbrecht, Tim; Heyder, Ursula; Cramer, Wolfgang

2006-01-01

Background Dynamic Global Vegetation Models (DGVMs) compute the terrestrial carbon balance as well as the transient spatial distribution of vegetation. We study two scenarios of moderate and strong climate change (2.9 K and 5.3 K temperature increase over present) to investigate the spatial redistribution of major vegetation types and their carbon balance in the year 2100. Results The world's land vegetation will be more deciduous than at present, and contain about 125 billion tons of additional carbon. While a recession of the boreal forest is simulated in some areas, along with a general expansion to the north, we do not observe a reported collapse of the central Amazonian rain forest. Rather, a decrease of biomass and a change of vegetation type occurs in its northeastern part. The ability of the terrestrial biosphere to sequester carbon from the atmosphere declines strongly in the second half of the 21st century. Conclusion Climate change will cause widespread shifts in the distribution of major vegetation functional types on all continents by the year 2100. PMID:16930462

The acclimation of Tilia cordata stomatal opening in response to light, and stomatal anatomy to vegetational shade and its components.

PubMed

Aasamaa, Krõõt; Aphalo, Pedro José

2017-02-01

Stomatal anatomical traits and rapid responses to several components of visible light were measured in Tilia cordata Mill. seedlings grown in an open, fully sunlit field (C-set), or under different kinds of shade. The main questions were: (i) stomatal responses to which visible light spectrum regions are modified by growth-environment shade and (ii) which separate component of vegetational shade is most effective in eliciting the acclimation effects of the full vegetational shade. We found that stomatal opening in response to red or green light did not differ between the plants grown in the different environments. Stomatal response to blue light was increased (in comparison with that of C-set) in the leaves grown in full vegetational shade (IABW-set), in attenuated UVAB irradiance (AB-set) or in decreased light intensity (neutral shade) plus attenuated UVAB irradiance (IAB-set). In all sets, the addition of green light-two or four times stronger-into induction light barely changed the rate of the blue-light-stimulated stomatal opening. In the AB-set, stomatal response to blue light equalled the strong IABW-set response. In attenuated UVB-grown leaves, stomatal response fell midway between IABW- and C-set results. Blue light response by neutral shade-grown leaves did not differ from that of the C-set, and the response by the IAB-set did not differ from that of the AB-set. Stomatal size was not modified by growth environments. Stomatal density and index were remarkably decreased only in the IABW- and IAB-sets. It was concluded that differences in white light responses between T. cordata leaves grown in different light environments are caused only by their different blue light response. Differences in stomatal sensitivity are not dependent on altered stomatal anatomy. Attenuated UVAB irradiance is the most efficient component of vegetational shade in stimulating acclimation of stomata, whereas decreased light intensity plays a minor role. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Trend shifts in satellite-derived vegetation growth in Central Eurasia, 1982-2013.

PubMed

Xu, Hao-Jie; Wang, Xin-Ping; Yang, Tai-Bao

2017-02-01

Central Eurasian vegetation is critical for the regional ecological security and the global carbon cycle. However, climatic impacts on vegetation growth in Central Eurasia are uncertain. The reason for this uncertainty lies in the fact that the response of vegetation to climate change showed nonlinearity, seasonality and differences among plant functional types. Based on remotely sensed vegetation index and in-situ meteorological data for the years 1982-2013, in conjunction with the latest land cover type product, we analyzed how vegetation growth trend varied across different seasons and evaluated vegetation response to climate variables at regional, biome and pixel scales. We found a persistent increase in the growing season NDVI over Central Eurasia during 1982-1994, whereas this greening trend has stalled since the mid-1990s in response to increased water deficit. The stalled trend in the growing season NDVI was largely attributed by summer and autumn NDVI changes. Enhanced spring vegetation growth after 2002 was caused by rapid spring warming. The response of vegetation to climatic factors varied in different seasons. Precipitation was the main climate driver for the growing season and summer vegetation growth. Changes in temperature and precipitation during winter and spring controlled the spring vegetation growth. Autumn vegetation growth was mainly dependent on the vegetation growth in summer. We found diverse responses of different vegetation types to climate drivers in Central Eurasia. Forests were more responsive to temperature than to precipitation. Grassland and desert vegetation responded more strongly to precipitation than to temperature in summer but more strongly to temperature than to precipitation in spring. In addition, the growth of desert vegetation was more dependent on winter precipitation than that of grasslands. This study has important implications for improving the performance of terrestrial ecosystem models to predict future vegetation response to climate change. Copyright © 2016 Elsevier B.V. All rights reserved.

Towards a theory of ecotone resilience: coastal vegetation on a salinity gradient.

PubMed

Jiang, Jiang; Gao, Daozhou; DeAngelis, Donald L

2012-08-01

Ecotones represent locations where vegetation change is likely to occur as a result of climate and other environmental changes. Using a model of an ecotone vulnerable to such future changes, we estimated the resilience of the ecotone to disturbances. The specific ecotone is that between two different vegetation types, salinity-tolerant and salinity-intolerant, along a gradient in groundwater salinity. In the case studied, each vegetation type, through soil feedback loops, promoted local soil salinity levels that favor itself in competition with the other type. Bifurcation analysis was used to study the system of equations for the two vegetation types and soil salinity. Alternative stable equilibria, one for salinity-tolerant and one for salinity intolerant vegetation, were shown to exist over a region of the groundwater salinity gradient, bounded by two bifurcation points. This region was shown to depend sensitively on parameters such as the rate of upward infiltration of salinity from groundwater into the soil due to evaporation. We showed also that increasing diffusion rates of vegetation can lead to shrinkage of the range between the two bifurcation points. Sharp ecotones are typical of salt-tolerant vegetation (mangroves) near the coastline and salt-intolerant vegetation inland, even though the underlying elevation and groundwater salinity change very gradually. A disturbance such as an input of salinity to the soil from a storm surge could upset this stable boundary, leading to a regime shift of salinity-tolerant vegetation inland. We showed, however, that, for our model as least, a simple pulse disturbance would not be sufficient; the salinity would have to be held at a high level, as a 'press', for some time. The approach used here should be generalizable to study the resilience of a variety of ecotones to disturbances. Published by Elsevier Inc.

Serving a variety of vegetables and fruit as a snack increased intake in preschool children.

PubMed

Roe, Liane S; Meengs, Jennifer S; Birch, Leann L; Rolls, Barbara J

2013-09-01

Although serving a greater variety of food increases intake, this effect has not been well studied as a strategy to encourage consumption of vegetables and fruit in preschool children. This study examined whether providing a variety of familiar vegetables or fruit to preschool children as a snack would lead to increased selection and intake. In a crossover design, 61 children (aged 3-5 y) ate a snack in their childcare facility on 8 afternoons. At 4 snack times, the children were offered vegetables: either a single type (cucumber, sweet pepper, or tomato) or a variety of all 3 types. At 4 other snack times, the children were offered fruit (apple, peach, pineapple, or all 3 types). Uniform-sized pieces were served family style, and children selected and ate as much as they desired. Offering a variety of vegetables or fruit increased the likelihood of selection (P < 0.0001); children chose some pieces in 94% of snacks with variety and in 70% of snacks without variety. Serving a variety also increased consumption of both vegetables and fruit (P < 0.0002); the mean (±SEM) increase was 31 ± 5 g, about one-sixth the recommended daily amount. Independent of the variety effect, children were less likely to select vegetables than fruit (P < 0.0001), and the mean intake was substantially less for vegetables than for fruit (22 ± 1 compared with 84 ± 3 g). Providing a variety of vegetables and fruit as a snack led to increased consumption of both food types in a childcare facility. Serving a variety of vegetables or fruit as a snack could help preschool children meet recommended intakes. This trial was registered at clinicaltrials.gov as NCT01557218.

Towards a theory of ecotone resilience: coastal vegetation on a salinity gradient

USGS Publications Warehouse

Jiang, Jiang; Gao, Daozhou; DeAngelis, Donald L.

2012-01-01

Ecotones represent locations where vegetation change is likely to occur as a result of climate and other environmental changes. Using a model of an ecotone vulnerable to such future changes, we estimated the resilience of the ecotone to disturbances. The specific ecotone is that between two different vegetation types, salinity-tolerant and salinity-intolerant, along a gradient in groundwater salinity. In the case studied, each vegetation type, through soil feedback loops, promoted local soil salinity levels that favor itself in competition with the other type. Bifurcation analysis was used to study the system of equations for the two vegetation types and soil salinity. Alternative stable equilibria, one for salinity-tolerant and one for salinity intolerant vegetation, were shown to exist over a region of the groundwater salinity gradient, bounded by two bifurcation points. This region was shown to depend sensitively on parameters such as the rate of upward infiltration of salinity from groundwater into the soil due to evaporation. We showed also that increasing diffusion rates of vegetation can lead to shrinkage of the range between the two bifurcation points. Sharp ecotones are typical of salt-tolerant vegetation (mangroves) near the coastline and salt-intolerant vegetation inland, even though the underlying elevation and groundwater salinity change very gradually. A disturbance such as an input of salinity to the soil from a storm surge could upset this stable boundary, leading to a regime shift of salinity-tolerant vegetation inland. We showed, however, that, for our model as least, a simple pulse disturbance would not be sufficient; the salinity would have to be held at a high level, as a 'press', for some time. The approach used here should be generalizable to study the resilience of a variety of ecotones to disturbances.

Serving a variety of vegetables and fruit as a snack increased intake in preschool children123

PubMed Central

Meengs, Jennifer S; Birch, Leann L; Rolls, Barbara J

2013-01-01

Background: Although serving a greater variety of food increases intake, this effect has not been well studied as a strategy to encourage consumption of vegetables and fruit in preschool children. Objective: This study examined whether providing a variety of familiar vegetables or fruit to preschool children as a snack would lead to increased selection and intake. Design: In a crossover design, 61 children (aged 3–5 y) ate a snack in their childcare facility on 8 afternoons. At 4 snack times, the children were offered vegetables: either a single type (cucumber, sweet pepper, or tomato) or a variety of all 3 types. At 4 other snack times, the children were offered fruit (apple, peach, pineapple, or all 3 types). Uniform-sized pieces were served family style, and children selected and ate as much as they desired. Results: Offering a variety of vegetables or fruit increased the likelihood of selection (P < 0.0001); children chose some pieces in 94% of snacks with variety and in 70% of snacks without variety. Serving a variety also increased consumption of both vegetables and fruit (P < 0.0002); the mean (±SEM) increase was 31 ± 5 g, about one-sixth the recommended daily amount. Independent of the variety effect, children were less likely to select vegetables than fruit (P < 0.0001), and the mean intake was substantially less for vegetables than for fruit (22 ± 1 compared with 84 ± 3 g). Conclusions: Providing a variety of vegetables and fruit as a snack led to increased consumption of both food types in a childcare facility. Serving a variety of vegetables or fruit as a snack could help preschool children meet recommended intakes. This trial was registered at clinicaltrials.gov as NCT01557218. PMID:23902783

Inventory and monitoring of natural vegetation and related resources in an arid environment by the use of ERTS-A imagery

NASA Technical Reports Server (NTRS)

Schrumpf, B. J. (Principal Investigator)

1972-01-01

The author has identified the following significant results. The southern Arizona test site includes vegetation representing shrub types of the Sonoran and Chihuahuan Deserts and Arizona chaparral. Also represented are grassland types of the desert grassland, juniper, and oak woodland types, and coniferous forest types. Relationships between plant species and selected terrain features are given along with the terrain feature classes used for the analyses. The purpose for determining the degree to which such relationships exist is to develop a body of knowledge to constitute the associated evidence that a photointerpreter may consult when interpreting vegetation subjects on small scale imagery. Imagery of this scale class contains little image detail which can be interpreted directly in terms of vegetation. On the other hand, some terrain features are the most salient features of that same imagery. Exploitation of those features for vegetation identification, inventory, and analysis can be accomplished only after establishing the existence of ecological relationships.

A fully traits-based approach to modeling global vegetation distribution.

PubMed

van Bodegom, Peter M; Douma, Jacob C; Verheijen, Lieneke M

2014-09-23

Dynamic Global Vegetation Models (DGVMs) are indispensable for our understanding of climate change impacts. The application of traits in DGVMs is increasingly refined. However, a comprehensive analysis of the direct impacts of trait variation on global vegetation distribution does not yet exist. Here, we present such analysis as proof of principle. We run regressions of trait observations for leaf mass per area, stem-specific density, and seed mass from a global database against multiple environmental drivers, making use of findings of global trait convergence. This analysis explained up to 52% of the global variation of traits. Global trait maps, generated by coupling the regression equations to gridded soil and climate maps, showed up to orders of magnitude variation in trait values. Subsequently, nine vegetation types were characterized by the trait combinations that they possess using Gaussian mixture density functions. The trait maps were input to these functions to determine global occurrence probabilities for each vegetation type. We prepared vegetation maps, assuming that the most probable (and thus, most suited) vegetation type at each location will be realized. This fully traits-based vegetation map predicted 42% of the observed vegetation distribution correctly. Our results indicate that a major proportion of the predictive ability of DGVMs with respect to vegetation distribution can be attained by three traits alone if traits like stem-specific density and seed mass are included. We envision that our traits-based approach, our observation-driven trait maps, and our vegetation maps may inspire a new generation of powerful traits-based DGVMs.

Model studies of migration from paper and board into fruit and vegetables and into Tenax as a food simulant.

PubMed

Bradley, E L; Castle, L; Speck, D R

2014-01-01

Four samples of paper and board (P/B) of a type used for packaging dry foods were subjected to migration tests using mushrooms, apples, potatoes and bananas, and using the polymeric powder Tenax as a food simulant. The P/B samples contained only low levels of diisopropylnaphthalene (DiPN) and diisobutyl phthalate (DiBP) and so the experiments were conducted after impregnating the P/B with added model substances. These were o-xylene, acetophenone, dodecane, benzophenone, DiPN and DiBP. Migration levels depended strongly on the nature of the substance and on the nature of the food and much less on the characteristics of the P/B, except insofar as they affected the contact area - flexible papers giving more extensive contact with the food than thick rigid board. Migration into Tenax was at least a factor of 10 higher than migration into the fresh fruit and vegetables. The food samples were placed in contact with the P/B and then overwrapped loosely with aluminium foil and so this correction factor will tend to be conservative compared with a more open storage of the packed foods. Washing, peeling or cooking the fruits and vegetables after contact with the P/B had a surprisingly small effect on contaminant levels in general, and no one processing step was effective in giving a significant reduction of all the types of chemicals studied. This was because either they had penetrated into the food (so resisting peeling), or were not freely water-soluble (so resisting washing) or were not particularly volatile (so resisting loss by evaporation during cooking).

Classification of the forest vegetation on the National Forests of Arizona and New Mexico

Treesearch

Robert R. Alexander; Frank Ronco

1987-01-01

Forest vegetation classified by habitat types and community types in Arizona and New Mexico are tabulated. Eleven series and 123 habitat and community types are identified; however, these habitat types and community types have been grouped into a lesser number of categories having similar characteristics or synonymous names. The table includes the name, location,...

Restoration of temperate savannas and woodlands

Treesearch

Brice B. Hanberry; John M. Kabrick; Peter W. Dunwiddie; Tibor Hartel; Theresa B. Jain; Benjamin O. Knapp

2017-01-01

Savannas and woodlands are open forest phases that occur along a gradient between grasslands and closed canopy forests. These ecosystems are characterized by open to nearly closed canopies of overstorey trees, relatively sparse midstorey and understorey woody vegetation, and dense, species-rich ground flora. In contrast to closed forests, the dominant and codominant...

Grafting Technique to Eliminate Rootstock Suckering of Grafted Tomatoes

USDA-ARS?s Scientific Manuscript database

Vegetable grafting has been proposed as a technique for avoiding disease problems in tomatoes in open field production. In this study we investigated the current use of grafting in an open field scenario and found a serious problem with the grafting techniques. In the Fall of 2007, commercially pr...

Sulfuric acid as a catalyst for ring-opening of biobased bis-epoxides

USDA-ARS?s Scientific Manuscript database

Vegetable oils can be relatively and easily transformed into bio-based epoxides. Because of this, the acid-catalyzed epoxide ring-opening has been explored for the preparation of bio-based lubricants and polymers. Detailed model studies are carried out only with mono-epoxide made from methyl oleate,...

Pipeline corridors through wetlands -- Impacts on plant communities: Little Timber Creek Crossing, Gloucester County, New Jersey. Topical report, August 1991--January 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shem, L.M.; Zimmerman, R.E.; Alsum, S.K.

1994-12-01

The goal of the Gas Research Institute Wetland Corridors Program is to document impacts of existing pipelines on the wetlands they traverse. To accomplish this goal, 12 existing wetland crossings were surveyed. These sites varied in elapsed time since pipeline construction, wetland type, pipeline installation techniques, and right-of-way (ROW) management practices. This report presents results of a survey conducted over the period of August 5--7, 1991, at the Little Timber Creek crossing in Gloucester County, New Jersey, where three pipelines, constructed in 1950, 1960, and 1990, cross the creek and associated wetlands. The old side of the ROW, created bymore » the installation of the 1960 pipeline, was designed to contain a raised peat bed over the 1950 pipeline and an open-water ditch over the 1960 pipeline. The new portion of the ROW, created by installation of the 1990 pipeline, has an open-water ditch over the pipeline (resulting from settling of the backfill) and a raised peat bed (resulting from rebound of compacted peat). Both the old and new ROWs contain dense stands of herbs; the vegetation on the old ROW was more similar to that in the adjacent natural area than was vegetation in the new ROW. The ROW increased species and habitat diversity in the wetlands. It may contribute to the spread of purple loosestrife and affect species sensitive to habitat fragmentation.« less

Removing forest canopy cover restores a reptile assemblage.

PubMed

Pike, David A; Webb, Jonathan K; Shine, Richard

2011-01-01

Humans are rapidly altering natural systems, leading to changes in the distribution and abundance of species. However, so many changes are occurring simultaneously (e.g., climate change, habitat fragmentation) that it is difficult to determine the cause of population fluctuations from correlational studies. We used a manipulative field experiment to determine whether forest canopy cover directly influences reptile assemblages on rock outcrops in southeastern Australia. Our experimental design consisted of three types of rock outcrops: (1) shady sites in which overgrown vegetation was manually removed (n = 25); (2) overgrown controls (n = 30); and (3) sun-exposed controls (n = 20). Following canopy removal, we monitored reptile responses over 30 months. Canopy removal increased reptile species richness, the proportion of shelter sites used by reptiles, and relative abundances of five species that prefer sun-exposed habitats. Our manipulation also decreased the abundances of two shade-tolerant species. Canopy cover thus directly influences this reptile assemblage, with the effects of canopy removal being dependent on each species' habitat preferences (i.e., selection or avoidance of sun-exposed habitat). Our study suggests that increases in canopy cover can cause declines of open-habitat specialists, as previously suggested by correlative studies from a wide range of taxa. Given that reptile colonization of manipulated outcrops occurred rapidly, artificially opening the canopy in ecologically informed ways could help to conserve imperiled species with patchy distributions and low vagility that are threatened by vegetation overgrowth. One such species is Australia's most endangered snake, the broadheaded snake (Hoplocephalus bungaroides).

Retronasal olfaction in vegetable liking and disliking.

PubMed

Lim, Juyun; Padmanabhan, Arthi

2013-01-01

While previous research has suggested that bitterness is a key determinant of vegetable rejection, it is unknown what role odor may play. We therefore investigated the impact of retronasal odors on hedonic responses to 4 vegetables. Subjects (N = 132) tasted small samples with the nose open and closed and rated the degree of liking/disliking, as well as the perceived intensity of sweetness, bitterness, saltiness, and vegetable flavor. The subjects were classified as "likers" or "dislikers" of each vegetable. The degree to which "likers" liked and "dislikers" disliked the vegetables was significantly less in the nose-closed condition, indicating that retronasal odor was a significant driver of vegetable hedonics. In contrast, bitterness ratings for all 4 vegetables did not differ significantly between the groups. The perceived intensity of vegetable flavor also did not differ significantly between groups, implying that the quality of vegetable odors rather than their perceived intensity drove the hedonic ratings. In a follow-up experiment, returning subjects (N = 89) rated the degree of liking/disliking of the vegetable odors alone, which were presented retronasally. Liking/disliking of specific odors was positively correlated with that for the sampled vegetables across all stimuli (r = 0.32~0.57). Overall, these results suggest that retronasal odor plays an important role in vegetable liking/disliking.

Critical thickness ratio for buckled and wrinkled fruits and vegetables

NASA Astrophysics Data System (ADS)

Dai, Hui-Hui; Liu, Yang

2014-11-01

This work aims at establishing the geometrical constraint for buckled and wrinkled shapes by modeling a fruit/vegetable with exocarp and sarcocarp as a hyperelastic layer-substrate structure subjected to uniaxial compression. A careful analysis on the derived bifurcation condition leads to the finding of a critical thickness ratio which separates the buckling and wrinkling modes, and remarkably, which is independent of the material stiffnesses. More specifically, it is found that if the thickness ratio is smaller than this critical value a fruit/vegetable should be in a buckled shape (under a sufficient stress); if a fruit/vegetable is in a wrinkled shape the thickness ratio is always larger than this critical value. To verify the theoretical prediction, we consider four types of buckled fruits/vegetables and four types of wrinkled fruits/vegetables with three samples in each type. The geometrical parameters for the 24 samples are measured and it is found that indeed all the data fall into the theoretically predicted buckling or wrinkling domains.

Simulated climate change: The interaction between vegetation type and microhabitat temperatures at Ny Alesund, Svalbard

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coulson, S.; Hodkinson, I.D.; Stathdee, A.

1993-01-01

Small polythene tents were used to simulate the effects of climate warming on two contrasting vegetation types (polar semi-desert and tundra heath) at Ny Alesund, Spitzbergen, Svalbard. Temperature microclimates are compared within and without tents and between sites with contrasting vegetation types. Summer temperatures were increased by about 5[degrees]C in the vegetation mat and by about 2[degrees]C in the soil at 3 cm depth. Cumulative day degrees above zero were enhanced by around 35% in the vegetation and by around 9% in the soil. Soil temperatures were greatly influenced by the nature of the overlying vegetation, which at one ofmore » the sites appeared to act as an efficient thermal insulator, preventing heat conductance into the soil from above and enhancing thermal contact between the upper soil layer and the cooling permafrost below. The significance of the observed temperature differences for the ecology of the plants and invertebrates is discussed. 21 refs., 3 figs., 2 tabs.« less

Alien plant invasion in mixed-grass prairie: effects of vegetation type, stochiasticity, and anthropogenic disturbance in two park units

USGS Publications Warehouse

Larson, Diane L.; Anderson, Patrick J.; Newton, Wesley E.

2001-01-01

The ability of alien plant species to invade a region depends not only on attributes of the plant, but on characteristics of the habitat being invaded. Here, we examine characteristics that may influence the success of alien plant invasion in mixed-grass prairie at Theodore Roosevelt National Park, in western North Dakota, USA. The park consists of two geographically separate units with similar vegetation types and management history, which allowed us to examine the effects of native vegetation type, anthropogenic disturbance, and the separate park units on the invasion of native plant communities by alien plant species common to counties surrounding both park units. If matters of chance related to availability of propagules and transient establishment opportunities determine the success of invasion, park unit and anthropogenic disturbance should better explain the variation in alien plant frequency. If invasibility is more strongly related to biotic or physical characteristics of the native plant communities, models of alien plant occurrence should include vegetation type as an explanatory variable. We examined >1300 transects across all vegetation types in both units of the park. Akaike's Information Criterion (AIC) indicated that the fully parameterized model, including the interaction among vegetation type, disturbance, and park unit, best described the distribution of both total number of alien plants per transect and frequency of alien plants on transects where they occurred. Although all vegetation types were invaded by alien plants, mesic communities had both greater numbers and higher frequencies of alien plants than did drier communities. A strong element of stochasticity, reflected in differences in frequencies of individual species between the two park units, suggests that prediction of risk of invasion will always involve uncertainty. In addition, despite well-documented associations between anthropogenic disturbance and alien plant invasion, five of the six most abundant alien species at Theodore Roosevelt National Park had distributions unrelated to disturbance. We recommend that vegetation type be explicitly taken into account when designing monitoring plans for alien species in natural areas.

Methane emissions from tundra environments in the Yukon-Kuskokwin Delta, Alaska

NASA Technical Reports Server (NTRS)

Bartlett, Karen B.; Crill, Patrick M.; Sass, Ronald L.; Harriss, Robert C.; Dise, Nancy B.

1992-01-01

This paper reports CH4 flux to the atmosphere from a variety of tundra environments near Bethel, Alaska during the summer months of 1988. Emissions from wet meadow tundra averaged 144 +/- 31 mg/sq m/d and ranged from 15.6 to 426 mg/sq m/d varying with soil moisture and temperature. Flux from the drier upland tundra was about two orders of magnitude lower and averaged 2.3 +/- 1.1 mg/sq m/d. Tundra lakes emit CH4 from the open water surface as well as from fringing aquatic vegetation; the presence of vegetation significantly enhanced flux over open water rates. Calculated diffusive fluxes from open water varied with lake size, the large lakes emitting 3.8 mg/sq m/d and small lakes emitting an average of 77 mg/sq m/d. An updated estimate of global emissions from tundra indicates an annual fluxes of approximately 11 +/- 3 Tg CH4.

Thermal remote sensing of active vegetation fires and biomass burning events [Chapter 18

Treesearch

Martin J. Wooster; Gareth Roberts; Alistair M.S. Smith; Joshua Johnston; Patrick Freeborn; Stefania Amici; Andrew T. Hudak

2013-01-01

Thermal remote sensing is widely used in the detection, study, and management of biomass burning occurring in open vegetation fires. Such fires may be planned for land management purposes, may occur as a result of a malicious or accidental ignition by humans, or may result from lightning or other natural phenomena. Under suitable conditions, fires may spread rapidly...

Strategies for detection of floodplain inundation with multi-frequency polarimetric SAR

NASA Technical Reports Server (NTRS)

Hess, Laura L.; Melack, John M.

1992-01-01

Mapping of floodplain inundation patterns is a key element in developing hydrological and biogeochemical models for large tropical river basins such as the Amazon. Knowledge of the time sequence of inundation is necessary to determine both water routing and biogenic gas fluxes. Synthetic Aperture Radar (SAR) is uniquely suited for this application because of its ability to penetrate cloud cover and, in many cases, to detect flooding beneath a forest or herbaceous canopy. A procedure for discriminating flooded forest, flooded herbaceous vegetation, and open water from other cover types for a coastal wetland site on the lower Altamaha floodplain, Georgia, emphasizing robust classifiers that are not site-specific is currently being developed.

Exploring vegetation in the fourth dimension.

PubMed

Mitchell, Fraser J G

2011-01-01

Much ecological research focuses on changes in vegetation on spatial scales from stands to landscapes; however, capturing data on vegetation change over relevant timescales remains a challenge. Pollen analysis offers unrivalled access to data with global coverage over long timescales. Robust techniques have now been developed that enable pollen data to be converted into vegetation data in terms of individual taxa, plant communities or biomes, with the possibility of deriving from those data a range of plant attributes and ecological indicators. In this review, I discuss how coupling pollen with macrofossil, charcoal and genetic data opens up the extensive pollen databases to investigation of the drivers of vegetation change over time and also provides extensive data sets for testing hypotheses with wide ecological relevance. © 2010 Elsevier Ltd. All rights reserved.

Diversity and Impacts of Mining on the Non-Volant Small Mammal Communities of Two Vegetation Types in the Brazilian Amazon.

PubMed

Ardente, Natália Carneiro; Ferreguetti, Átilla Colombo; Gettinger, Donald; Leal, Pricila; Mendes-Oliveira, Ana Cristina; Martins-Hatano, Fernanda; Bergallo, Helena Godoy

2016-01-01

The Carajás National Forest contains some of the largest iron ore deposits in the world. The majority of the minerals are found below a plant community known as Savana Metalófila, or "Canga", which represents only 3% of the landscape within the Carajás National Forest (CNF). The aim of our study was to understand the diversity of community of non-volant small mammals in the two predominant vegetation types: Ombrophilous Forest and Canga, and to examine how mining impacts these communities. Sampling was conducted from January 2010 to August 2011 in 11 sampling sites divided by the total area of Canga and 12 sampling sites in the forest, totalizing 23 sites. Of these, 12 sites (Canga and Forest) were considered impacted areas located close to the mine (< 900 meters) and 11 sites (Canga and Forest), serving as controls, which were at least 7,000 meters from the mine. We recorded 28 species, 11 from the Order Didelphimorphia and 17 from the Order Rodentia. The two forest types shared 68.42% of the species found in the CNF. A gradient analysis (Non-metric multidimensional scaling) revealed that the first axis clearly separated the non-flying small mammal communities by vegetation type. Occupancy models showed that the detectability of species was affected by the distance from the mining activities. Of all the small mammals analyzed, 10 species were positively affected by the distance from mining in areas impacted (e.g. more likely to be detected farther from mining areas) and detectability was lower in impacted areas. However, three species were negatively affected by the distance from mining, with higher detectability in the impacted areas, and seven species showed no effect of their proximity to mining operations. To date, there are no studies in Brazil about the impact of mining on mammals or other vertebrates. This study reveals that the effect of mining may go beyond the forest destruction caused by the opening of the mining pits, but also may negatively affect sensitive wildlife species.

Diversity and Impacts of Mining on the Non-Volant Small Mammal Communities of Two Vegetation Types in the Brazilian Amazon

PubMed Central

Ardente, Natália Carneiro; Ferreguetti, Átilla Colombo; Gettinger, Donald; Leal, Pricila; Mendes-Oliveira, Ana Cristina; Martins-Hatano, Fernanda; Bergallo, Helena Godoy

2016-01-01

The Carajás National Forest contains some of the largest iron ore deposits in the world. The majority of the minerals are found below a plant community known as Savana Metalófila, or “Canga”, which represents only 3% of the landscape within the Carajás National Forest (CNF). The aim of our study was to understand the diversity of community of non-volant small mammals in the two predominant vegetation types: Ombrophilous Forest and Canga, and to examine how mining impacts these communities. Sampling was conducted from January 2010 to August 2011 in 11 sampling sites divided by the total area of Canga and 12 sampling sites in the forest, totalizing 23 sites. Of these, 12 sites (Canga and Forest) were considered impacted areas located close to the mine (<< 900 meters) and 11 sites (Canga and Forest), serving as controls, which were at least 7,000 meters from the mine. We recorded 28 species, 11 from the Order Didelphimorphia and 17 from the Order Rodentia. The two forest types shared 68.42% of the species found in the CNF. A gradient analysis (Non-metric multidimensional scaling) revealed that the first axis clearly separated the non-flying small mammal communities by vegetation type. Occupancy models showed that the detectability of species was affected by the distance from the mining activities. Of all the small mammals analyzed, 10 species were positively affected by the distance from mining in areas impacted (e.g. more likely to be detected farther from mining areas) and detectability was lower in impacted areas. However, three species were negatively affected by the distance from mining, with higher detectability in the impacted areas, and seven species showed no effect of their proximity to mining operations. To date, there are no studies in Brazil about the impact of mining on mammals or other vertebrates. This study reveals that the effect of mining may go beyond the forest destruction caused by the opening of the mining pits, but also may negatively affect sensitive wildlife species. PMID:27893798

LANDFIRE 2015 Remap – Utilization of Remotely Sensed Data to Classify Existing Vegetation Type and Structure to Support Strategic Planning and Tactical Response

USGS Publications Warehouse

Picotte, Joshua J.; Long, Jordan; Peterson, Birgit; Nelson, Kurtis

2017-01-01

The LANDFIRE Program produces national scale vegetation, fuels, fire regimes, and landscape disturbance data for the entire U.S. These data products have been used to model the potential impacts of fire on the landscape [1], the wildfire risks associated with land and resource management [2, 3], and those near population centers and accompanying Wildland Urban Interface zones [4], as well as many other applications. The initial LANDFIRE National Existing Vegetation Type (EVT) and vegetation structure layers, including vegetation percent cover and height, were mapped circa 2001 and released in 2009 [5]. Each EVT is representative of the dominant plant community within a given area. The EVT layer has since been updated by identifying areas of landscape change and modifying the vegetation types utilizing a series of rules that consider the disturbance type, severity of disturbance, and time since disturbance [6, 7]. Non-disturbed areas were adjusted for vegetation growth and succession. LANDFIRE vegetation structure layers also have been updated by using data modeling techniques [see 6 for a full description]. The subsequent updated versions of LANDFIRE include LANDFIRE 2008, 2010, 2012, and LANDFIRE 2014 is being incrementally released, with all data being released in early 2017. Additionally, a comprehensive remap of the baseline data, LANDFIRE 2015 Remap, is being prototyped, and production is tentatively planned to begin in early 2017 to provide a more current baseline for future updates.

Response of the Amazon rainforest to late Pleistocene climate variability

NASA Astrophysics Data System (ADS)

Häggi, Christoph; Chiessi, Cristiano M.; Merkel, Ute; Mulitza, Stefan; Prange, Matthias; Schulz, Michael; Schefuß, Enno

2017-12-01

Variations in Amazonian hydrology and forest cover have major consequences for the global carbon and hydrological cycles as well as for biodiversity. Yet, the climate and vegetation history of the lowland Amazon basin and its effect on biogeography remain debated due to the scarcity of suitable high-resolution paleoclimate records. Here, we use the isotopic composition (δD and δ13C) of plant-waxes from a high-resolution marine sediment core collected offshore the Amazon River to reconstruct the climate and vegetation history of the integrated lowland Amazon basin for the period from 50,000 to 12,800 yr before present. Our results show that δD values from the Last Glacial Maximum were more enriched than those from Marine Isotope Stage (MIS) 3 and the present-day. We interpret this trend to reflect long-term changes in precipitation and atmospheric circulation, with overall drier conditions during the Last Glacial Maximum. Our results thus suggest a dominant glacial forcing of the climate in lowland Amazonia. In addition to previously suggested thermodynamic mechanisms of precipitation change, which are directly related to temperature, we conclude that changes in atmospheric circulation are crucial to explain the temporal evolution of Amazonian rainfall variations, as demonstrated in climate model experiments. Our vegetation reconstruction based on δ13C values shows that the Amazon rainforest was affected by intrusions of savannah or more open vegetation types in its northern sector during Heinrich Stadials, while it was resilient to glacial drying. This suggests that biogeographic patterns in tropical South America were affected by Heinrich Stadials in addition to glacial-interglacial climate variability.

A spatial simulation model of hydrology and vegetation dynamics in semi-permanent prairie wetlands

USGS Publications Warehouse

Poiani, Karen A.; Johnson, W. Carter

1993-01-01

The objective of this study was to construct a spatial simulation model of the vegetation dynamics in semi-permanent prairie wetlands. A hydrologic submodel estimated water levels based on precipitation, runoff, and potential evapotranspiration. A vegetation submodel calculated the amount and distribution of emergent cover and open water using a geographic information system. The response of vegetation to water-level changes was based on seed bank composition, seedling recruitment and establishment, and plant survivorship. The model was developed and tested using data from the Cottonwood Lake study site in North Dakota. Data from semi-permanent wetland P1 were used to calibrate the model. Data from a second wetland, P4, were used to evaluate model performance. Simulation results were compared with actual water data from 1797 through 1989. Test results showed that differences between calculated and observed water levels were within 10 cm 75% of the time. Open water over the past decade ranged from 0 to 7% in wetland P4 and from 0 to 8% in submodel simulations. Several model parameters including evapotranspiration and timing of seedling germination could be improved with more complex techniques or relatively minor adjustments. Despite these differences the model adequately represented vegetation dynamics of prairie wetlands and can be used to examine wetland response to natural or human-induced climate change.

Habitat associations of species show consistent but weak responses to climate

PubMed Central

Suggitt, Andrew J.; Stefanescu, Constantí; Páramo, Ferran; Oliver, Tom; Anderson, Barbara J.; Hill, Jane K.; Roy, David B.; Brereton, Tom; Thomas, Chris D.

2012-01-01

Different vegetation types can generate variation in microclimates at local scales, potentially buffering species from adverse climates. To determine if species could respond to such microclimates under climatic warming, we evaluated whether ectothermic species (butterflies) can exploit favourable microclimates and alter their use of different habitats in response to year-to-year variation in climate. In both relatively cold (Britain) and warm (Catalonia) regions of their geographical ranges, most species shifted into cooler, closed habitats (e.g. woodland) in hot years, and into warmer, open habitats (e.g. grassland) in cooler years. Additionally, three-quarters of species occurred in closed habitats more frequently in the warm region than in the cool region. Thus, species shift their local distributions and alter their habitat associations to exploit favourable microclimates, although the magnitude of the shift (approx. 1.3% of individuals from open to shade, per degree Celsius) is unlikely to buffer species from impacts of regional climate warming. PMID:22491762

BOUNDARY SHEAR STRESS ALONG VEGETATED STREAMBANKS

EPA Science Inventory

This research is intended to improve our understanding of the role of riparian vegetation in stream morphology by evaluating the effects of vegetation on boundary shear stress, providing insight to the type and density of vegetation required for streambank stability. The resu...

An experimental test of matrix permeability and corridor use by an endemic understory bird.

PubMed

Castellón, Traci D; Sieving, Kathryn E

2006-02-01

Because of widespread habitat fragmentation, maintenance of landscape connectivity has become a major focus of conservation planning, but empirical tests of animal movement in fragmented landscapes remain scarce. We conducted a translocation experiment to test the relative permeability of three landscape elements (open habitat, shrubby secondary vegetation, and wooded corridors) to movement by the Chucao Tapaculo (Scelorchilus rubecula), a forest understory bird endemic to South American temperate rainforest. Forty-one radio-tagged subjects were translocated (individually) to three landscape treatments consisting of small release patches that were either entirely surrounded by open habitat (pasture), entirely surrounded by dense shrubs, or linked to other patches by wooded corridors that were otherwise surrounded by open matrix. The number of days subjects remained in release patches before dispersal (a measure of habitat resistance) was significantly longer for patches surrounded by open habitat than for patches adjoining corridors or surrounded by dense shrubs. These results indicate that open habitat significantly constrains Chucao dispersal, in accord with expectation, but dispersal occurs equally well through wooded corridors and shrub-dominated matrix. Thus, corridor protection or restoration and management of vegetation in the matrix (to encourage animal movement) may be equally feasible alternatives for maintaining connectivity.

Paleoecological reconstruction of hominin-bearing middle Pliocene localities at Woranso-Mille, Ethiopia.

PubMed

Curran, Sabrina C; Haile-Selassie, Yohannes

2016-07-01

Woranso-Mille is a paleoanthropological site in Ethiopia sampling an important and under-represented time period in human evolution (3.8-3.6 million years ago). Specimens of cf. Australopithecus anamensis, Australopithecus afarensis, and the recently named Australopithecus deyiremeda have been recovered from this site. Using multiple habitat proxies, this study provides a paleoecological reconstruction of two fossiliferous collection areas from Woranso-Mille, Aralee Issie (ARI) and Mesgid Dora (MSD). Previous reconstructions based on faunal assemblages have pointed, due to the presence of aepycerotins, alcelaphins, and proboscideans, to the existence of open habitats as well as more closed ones, based on the occurrence of cercopithecids, giraffids, and traglephins. Results from community structure analysis (proportions of locomotor and dietary adaptations) at ARI and MSD indicated a predominance of open habitats, such as shrublands. Mesowear analysis revealed that ungulates of all dietary types (grazers, leaf and fruit browsers, and mixed feeders) were present in nearly equal proportions. Ecomorphological analyses using linear measurements of the astragalus and phalanges indicated that bovids utilizing locomotor behaviors associated with all habitat types were present, though the intermediate-cover habitat bovids were best represented in the sample (Heavy cover at ARI and Light cover at MSD). Together, these results suggest that the ARI and MSD localities were heterogeneous habitats (mosaics), likely with densely vegetated areas along a paleo-river and more open regions (woodlands, grasslands) available away from the river. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chapter 3: Status and trends of vegetation

Treesearch

James M. Guldin; Frank R. Thompson; Lynda L. Richards; Kyra C. Harper

1999-01-01

This chapter provides information about the vegetation cover of the Assessment area. The types and areal extent of vegetation in the Highlands are of interest for many reasons. Vegetation cover largely determines the availability of habitat for terrestrial animals, plants, and other organisms. Vegetation cover strongly influences what uses {e.g., timber, forage,...

Monitoring of fire incidences in vegetation types and Protected Areas of India: Implications on carbon emissions

NASA Astrophysics Data System (ADS)

Reddy, C. Sudhakar; Padma Alekhya, V. V. L.; Saranya, K. R. L.; Athira, K.; Jha, C. S.; Diwakar, P. G.; Dadhwal, V. K.

2017-02-01

Carbon emissions released from forest fires have been identified as an environmental issue in the context of global warming. This study provides data on spatial and temporal patterns of fire incidences, burnt area and carbon emissions covering natural vegetation types (forest, scrub and grassland) and Protected Areas of India. The total area affected by fire in the forest, scrub and grasslands have been estimated as 48765.45, 6540.97 and 1821.33 km 2, respectively, in 2014 using Resourcesat-2 AWiFS data. The total CO 2 emissions from fires of these vegetation types in India were estimated to be 98.11 Tg during 2014. The highest emissions were caused by dry deciduous forests, followed by moist deciduous forests. The fire season typically occurs in February, March, April and May in different parts of India. Monthly CO 2 emissions from fires for different vegetation types have been calculated for February, March, April and May and estimated as 2.26, 33.53, 32.15 and 30.17 Tg, respectively. Protected Areas represent 11.46% of the total natural vegetation cover of India. Analysis of fire occurrences over a 10-year period with two types of sensor data, i.e., AWiFS and MODIS, have found fires in 281 (out of 614) Protected Areas of India. About 16.78 Tg of CO 2 emissions were estimated in Protected Areas in 2014. The natural vegetation types of Protected Areas have contributed for burnt area of 17.3% and CO 2 emissions of 17.1% as compared to total natural vegetation burnt area and emissions in India in 2014. 9.4% of the total vegetation in the Protected Areas was burnt in 2014. Our results suggest that Protected Areas have to be considered for strict fire management as an effective strategy for mitigating climate change and biodiversity conservation.

The effect of short ground vegetation on terrestrial laser scans at a local scale

NASA Astrophysics Data System (ADS)

Fan, Lei; Powrie, William; Smethurst, Joel; Atkinson, Peter M.; Einstein, Herbert

2014-09-01

Terrestrial laser scanning (TLS) can record a large amount of accurate topographical information with a high spatial accuracy over a relatively short period of time. These features suggest it is a useful tool for topographical survey and surface deformation detection. However, the use of TLS to survey a terrain surface is still challenging in the presence of dense ground vegetation. The bare ground surface may not be illuminated due to signal occlusion caused by vegetation. This paper investigates vegetation-induced elevation error in TLS surveys at a local scale and its spatial pattern. An open, relatively flat area vegetated with dense grass was surveyed repeatedly under several scan conditions. A total station was used to establish an accurate representation of the bare ground surface. Local-highest-point and local-lowest-point filters were applied to the point clouds acquired for deriving vegetation height and vegetation-induced elevation error, respectively. The effects of various factors (for example, vegetation height, edge effects, incidence angle, scan resolution and location) on the error caused by vegetation are discussed. The results are of use in the planning and interpretation of TLS surveys of vegetated areas.

Circumscribing campo rupestre - megadiverse Brazilian rocky montane savanas.

PubMed

Alves, R J V; Silva, N G; Oliveira, J A; Medeiros, D

2014-05-01

Currently campo rupestre (CR) is a name accepted and used internationally by botanists, zoologists, and other naturalists, usually applied to a very specific ecosystem, despite the lack of a consensual published circumscription. We present a tentative geographic circumscription of the term, combining data on climate, geology, geomorphology, soil, flora, fauna and vegetation. The circumscription of campo rupestre proposed herein is based on the following premises: (1) the classification of vegetation is not an exact science, and it is difficult to attain a high degree of consensus to the circumscription of vegetation names; (2) despite this, vegetation classification is useful for conservation and management. It is thus desirable to circumscribe vegetation types with the greatest attainable precision; (3) there is a need to preserve all montane and rocky vegetation types, regardless of classification, biome, etc; (4) the CRs are formed by a complex mosaic of vegetation types including rock-dwelling, psammophilous, aquatic, epiphytic, and penumbral plant communities. Campos rupestres stricto sensu are a Neotropical, azonal vegetation complex endemic to Brazil, forming a mosaic of rocky mountaintop "archipelagos" inserted within a matrix of zonal vegetation, mainly in the Cerrado and Caatinga provinces of the Brazilian Shield (southeastern, northeastern and central-western regions), occurring mainly above 900 m asl. up to altitudes exceeding 2000 m, having measured annual precipitation between 800 and 1500 mm, and an arid season of two to five months.

On the Mineral and Vegetal Oils Used as Electroinsulation in Transformers

NASA Astrophysics Data System (ADS)

Şerban, Mariana; Sângeorzan, Livia; Helerea, Elena

Due to the relatively large availability and reduced price, the mineral transformer oils are widely used as electrical insulating liquids. However, mineral oil drastically degrades over time in service. New efforts were made to improve mineral oils characteristics, and other types of liquids like vegetal oils are proposed. This paper deals with new comparative tests on mineral and vegetal oils using as indicator the electric strength. The samples of non-additive mineral oil type TR 30 and vegetal oils of rape, sunflower and corn have been tested with increasing voltage of 60 Hz using different electrodes. The obtained data have been statistical processed. The analyze shows different average values of electrical strength for the different type of sample. New method of testing through electrical breakdown is proposed. Experimental data confirms that it is possible to use as electroinsulation organic vegetal oils in power transformers.

Assessment of air pollution impacts on vegetation in South Africa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Botha, A.T.

1989-01-01

Field surveys and biomonitoring network experiments were conducted in selected areas in South Africa to assess possible air pollution damage to vegetation. During field surveys, atmospheric fluoride was identified as an important pollutant that damaged vegetation in residential areas north of Cape Town. Gaseous air pollutants, including acid deposition and acidic mist, probably play a major role in the development of characteristic air pollution injury symptoms observed on pine trees in the Eastern Transvaal area. The impact of urban air pollution in the Cape Town area was evaluated by exposing bio-indicator plants in a network of eight biomonitoring network stationsmore » from June 1985 to May 1988. Sensitive Freesia and Gladiolus cultivars were used to biomonitor atmospheric fluoride, while a green bean cultivar was used as a biomonitor of atmospheric sulfur dioxide and ozone. At one location, bio-indicator plants were simultaneously exposed in a biomonitoring network station, open-top chambers, as well as in open plots. The responses of plants grown under these different conditions were compared.« less

The Effects of Liking Norms and Descriptive Norms on Vegetable Consumption: A Randomized Experiment

PubMed Central

Thomas, Jason M.; Liu, Jinyu; Robinson, Eric L.; Aveyard, Paul; Herman, C. Peter; Higgs, Suzanne

2016-01-01

There is evidence that social norm messages can be used to promote the selection of fruit and vegetables in low habitual consumers of these foods but it is unclear whether this effect is sustained over time. It is also unclear whether information about others' liking for a food (liking norm) could have the same effect. Using a 2 × 5 × 2 experimental design we investigated the effects of exposure to various messages on later intake from a food buffet and whether any effects were sustained 24 h after exposure in both low and high consumers of vegetables. There were three factors: delay (immediate food selection vs. food selection 24 h after exposure), message type (liking norm, descriptive norm, health message, vegetable variety condition, and neutral control message), and habitual consumption (low vs. high). The buffet consisted of three raw vegetables, three energy-dense foods, and two dips. For vegetables and non-vegetables there were no main effects of message type, nor any main effect of delay. There was a significant message × habitual vegetable consumption interaction for vegetable consumption; however, follow up tests did not yield any significant effects. Examining each food individually, there were no main effects of message type, nor any main effect of delay, for any of the foods; however, there was a message × habitual vegetable consumption interaction for broccoli. Consumption of broccoli in the health message and descriptive norm conditions did not differ from the control neutral condition. However, habitually low consumers of vegetables increased their consumption of broccoli in the vegetable variety and liking norm conditions relative to habitual low vegetable consumers in the neutral control condition (p < 0.05). Further, investigation of the effects of the liking norm and vegetable variety condition on vegetable intake is warranted. This trial is listed as NCT02618174 at clinicaltrials.gov. PMID:27065913

The ecological variations in thermal infrared emissivity of vegetation. [in Texas, Arizona, New Mexico, and Mexico

NASA Technical Reports Server (NTRS)

Arp, G. K.; Phinney, D. E. (Principal Investigator)

1979-01-01

The author has identified the following significant results. Through a series of contrasts, the statistical significance of differences in emissivity was determined for vegegation in dry and humid deserts, montane and deciduous rain forests, and the temperate region. No significant differences were found between the two types of desert vegetation or among the types of nondesert vegetation. However, the rain forest vegetation was significantly different from that of the temperate region. On a community-wide level, there is some physiological adaptation in plants to their radiational environment.

Insights on the criteria of selection of vegetable and mineral dielectric fluids used in power transformers on the basis of their biodegradability and toxicity assessments.

PubMed

Módenes, Aparecido Nivaldo; Sanderson, Karina; Trigueros, Daniela Estelita Goes; Schuelter, Adilson Ricken; Espinoza-Quiñones, Fernando Rodolfo; Neves, Camila Vargas; Zanão Junior, Luiz Antônio; Kroumov, Alexander Dimitrov

2018-05-01

Leakage of transformer dielectric fluids is a concern because it may pose a risk of environmental contamination. In this study, the deleterious effects of vegetable and mineral dielectric fluids in water bodies were investigated using biodegradability and acute toxicity tests with Danio rerio and Artemia salina. Regarding biodegradability, all four tested vegetable oils (soy, canola, sunflower and crambe) were considered as easily biodegradable, presenting degradation rates significantly higher than the Lubrax-type mineral fluid. Acute toxicity tests were performed in two separate experiments without solution renewal. In the first experiment, the organisms were exposed in direct contact to different concentrations of vegetable (soy) and mineral (Lubrax) oils. Total soy-type vegetable oil has a higher toxic effect than Lubrax-type mineral oil. In the second experiment, the organisms were exposed to increasing percentages of the water-soluble fraction (WSF) of both types of tested oils. The LC 50 values for the water-soluble fraction of the Lubrax-type mineral oil were about 5 and 8% for the Danio rerio and Artemia salina bioindicators, respectively, whereas the vegetable oil did not present toxic effect, regardless of its WSF. These results have shown that a strict selection of dielectric fluids and monitoring the leakage from power transformers is a serious duty of environmental protection agencies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Multivariate ordination identifies vegetation types associated with spider conservation in brassica crops

PubMed Central

Saqib, Hafiz Sohaib Ahmed; You, Minsheng

2017-01-01

Conservation biological control emphasizes natural and other non-crop vegetation as a source of natural enemies to focal crops. There is an unmet need for better methods to identify the types of vegetation that are optimal to support specific natural enemies that may colonize the crops. Here we explore the commonality of the spider assemblage—considering abundance and diversity (H)—in brassica crops with that of adjacent non-crop and non-brassica crop vegetation. We employ spatial-based multivariate ordination approaches, hierarchical clustering and spatial eigenvector analysis. The small-scale mixed cropping and high disturbance frequency of southern Chinese vegetation farming offered a setting to test the role of alternate vegetation for spider conservation. Our findings indicate that spider families differ markedly in occurrence with respect to vegetation type. Grassy field margins, non-crop vegetation, taro and sweetpotato harbour spider morphospecies and functional groups that are also present in brassica crops. In contrast, pumpkin and litchi contain spiders not found in brassicas, and so may have little benefit for conservation biological control services for brassicas. Our findings also illustrate the utility of advanced statistical approaches for identifying spatial relationships between natural enemies and the land uses most likely to offer alternative habitats for conservation biological control efforts that generates testable hypotheses for future studies. PMID:29085741

Unmanned Aerial Vehicles Produce High-Resolution Seasonally-Relevant Imagery for Classifying Wetland Vegetation

NASA Astrophysics Data System (ADS)

Marcaccio, J. V.; Markle, C. E.; Chow-Fraser, P.

2015-08-01

With recent advances in technology, personal aerial imagery acquired with unmanned aerial vehicles (UAVs) has transformed the way ecologists can map seasonal changes in wetland habitat. Here, we use a multi-rotor (consumer quad-copter, the DJI Phantom 2 Vision+) UAV to acquire a high-resolution (< 8 cm) composite photo of a coastal wetland in summer 2014. Using validation data collected in the field, we determine if a UAV image and SWOOP (Southwestern Ontario Orthoimagery Project) image (collected in spring 2010) differ in their classification of type of dominant vegetation type and percent cover of three plant classes: submerged aquatic vegetation, floating aquatic vegetation, and emergent vegetation. The UAV imagery was more accurate than available SWOOP imagery for mapping percent cover of submergent and floating vegetation categories, but both were able to accurately determine the dominant vegetation type and percent cover of emergent vegetation. Our results underscore the value and potential for affordable UAVs (complete quad-copter system < 3,000 CAD) to revolutionize the way ecologists obtain imagery and conduct field research. In Canada, new UAV regulations make this an easy and affordable way to obtain multiple high-resolution images of small (< 1.0 km2) wetlands, or portions of larger wetlands throughout a year.

Sensitivity analysis of the Commonly Used Drought Indices on the different land use Types - Case Study over Turkey

NASA Astrophysics Data System (ADS)

Ersoy, E. N.; Hüsami Afşar, M.; Bulut, B.; Onen, A.; Yilmaz, M. T.

2017-12-01

Droughts are climatic phenomenon that may impact large and small regions alike for long or short time periods and influence society in terms of industrial, agricultural, domestic and many more aspects. The characteristics of the droughts are commonly investigated using indices like Standardized Precipitation Index (SPI), Palmer Drought Severity Index (PDSI), Standardized Precipitation Evapotranspiration Index (SPEI) and Normalized Difference Vegetation Index (NDVI). On the other hand, these indices may not necessarily yield similar performance over different vegetation types. The aim is to analyze the sensitivity of drought indices (SPI, SPEI, PDSI) to vegetation types over different climatic regions in Turkey. Here the magnitude of the drought severity is measured using MODIS NDVI data, while the vegetation type (e.g., non-irrigated arable lands, vineyards, fruit trees and berry plantations, olive groves, pastures, land principally occupied by agriculture) information is obtained using CORINE land cover classification. This study has compared the drought characteristics and vegetation conditions on different land use types using remotely sensed datasets (e.g., CORINE land use data, MODIS NDVI), and commonly used drought indices between 2000 and 2016 using gauge based precipitation and temperature measurements.

Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

NASA Astrophysics Data System (ADS)

McFarlane, S. A.; Gaustad, K. L.; Mlawer, E. J.; Long, C. N.; Delamere, J.

2011-09-01

We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

NASA Astrophysics Data System (ADS)

McFarlane, S. A.; Gaustad, K. L.; Mlawer, E. J.; Long, C. N.; Delamere, J.

2011-05-01

We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

Determination of plant characteristics used in discharge capacity assessment of Turkey Creek watershed on South Carolina coastal plain, USA

Treesearch

Dorota Miroslaw-Swiatek; Devendra M. Amatya

2011-01-01

Riparian vegetation type, composition, structure, and its abundance on floodplains exert a strong influence on riparian surface and subsurface hydrology and discharges of rivers and streams. The conditions of flood waters flow in such valley types are shaped by the existing vegetation cover. In this study, on the basis of vegetation inventory in four selected and...

The influence of parent material on vegetation response 15 years after the Dude Fire, Arizona

Treesearch

Jackson M. Leonard; Alvin L. Medina; Daniel G. Neary; Aregai Tecle

2015-01-01

This study examined the effects of two types of parent material, sandstone and limestone, on the response of vegetation growth after the 1990 Dude Fire in central Arizona. The operating hypothesis of the study was that, given the right conditions, severe wildfire can trigger vegetation type conversion. Overall, three patterns emerged: (1) oak density increased by 413%...

An object-based approach for tree species extraction from digital orthophoto maps

NASA Astrophysics Data System (ADS)

Jamil, Akhtar; Bayram, Bulent

2018-05-01

Tree segmentation is an active and ongoing research area in the field of photogrammetry and remote sensing. It is more challenging due to both intra-class and inter-class similarities among various tree species. In this study, we exploited various statistical features for extraction of hazelnut trees from 1 : 5000 scaled digital orthophoto maps. Initially, the non-vegetation areas were eliminated using traditional normalized difference vegetation index (NDVI) followed by application of mean shift segmentation for transforming the pixels into meaningful homogeneous objects. In order to eliminate false positives, morphological opening and closing was employed on candidate objects. A number of heuristics were also derived to eliminate unwanted effects such as shadow and bounding box aspect ratios, before passing them into the classification stage. Finally, a knowledge based decision tree was constructed to distinguish the hazelnut trees from rest of objects which include manmade objects and other type of vegetation. We evaluated the proposed methodology on 10 sample orthophoto maps obtained from Giresun province in Turkey. The manually digitized hazelnut tree boundaries were taken as reference data for accuracy assessment. Both manually digitized and segmented tree borders were converted into binary images and the differences were calculated. According to the obtained results, the proposed methodology obtained an overall accuracy of more than 85 % for all sample images.

Impact of trees on pollutant dispersion in street canyons: A numerical study of the annual average effects in Antwerp, Belgium.

PubMed

Vranckx, Stijn; Vos, Peter; Maiheu, Bino; Janssen, Stijn

2015-11-01

Effects of vegetation on pollutant dispersion receive increased attention in attempts to reduce air pollutant concentration levels in the urban environment. In this study, we examine the influence of vegetation on the concentrations of traffic pollutants in urban street canyons using numerical simulations with the CFD code OpenFOAM. This CFD approach is validated against literature wind tunnel data of traffic pollutant dispersion in street canyons. The impact of trees is simulated for a variety of vegetation types and the full range of approaching wind directions at 15° interval. All these results are combined using meteo statistics, including effects of seasonal leaf loss, to determine the annual average effect of trees in street canyons. This analysis is performed for two pollutants, elemental carbon (EC) and PM10, using background concentrations and emission strengths for the city of Antwerp, Belgium. The results show that due to the presence of trees the annual average pollutant concentrations increase with about 8% (range of 1% to 13%) for EC and with about 1.4% (range of 0.2 to 2.6%) for PM10. The study indicates that this annual effect is considerably smaller than earlier estimates which are generally based on a specific set of governing conditions (1 wind direction, full leafed trees and peak hour traffic emissions). Copyright © 2015 Elsevier B.V. All rights reserved.

Metabolic engineering of biomass for high energy density: oilseed-like triacylglycerol yields from plant leaves.

PubMed

Vanhercke, Thomas; El Tahchy, Anna; Liu, Qing; Zhou, Xue-Rong; Shrestha, Pushkar; Divi, Uday K; Ral, Jean-Philippe; Mansour, Maged P; Nichols, Peter D; James, Christopher N; Horn, Patrick J; Chapman, Kent D; Beaudoin, Frederic; Ruiz-López, Noemi; Larkin, Philip J; de Feyter, Robert C; Singh, Surinder P; Petrie, James R

2014-02-01

High biomass crops have recently attracted significant attention as an alternative platform for the renewable production of high energy storage lipids such as triacylglycerol (TAG). While TAG typically accumulates in seeds as storage compounds fuelling subsequent germination, levels in vegetative tissues are generally low. Here, we report the accumulation of more than 15% TAG (17.7% total lipids) by dry weight in Nicotiana tabacum (tobacco) leaves by the co-expression of three genes involved in different aspects of TAG production without severely impacting plant development. These yields far exceed the levels found in wild-type leaf tissue as well as previously reported engineered TAG yields in vegetative tissues of Arabidopsis thaliana and N. tabacum. When translated to a high biomass crop, the current levels would translate to an oil yield per hectare that exceeds those of most cultivated oilseed crops. Confocal fluorescence microscopy and mass spectrometry imaging confirmed the accumulation of TAG within leaf mesophyll cells. In addition, we explored the applicability of several existing oil-processing methods using fresh leaf tissue. Our results demonstrate the technical feasibility of a vegetative plant oil production platform and provide for a step change in the bioenergy landscape, opening new prospects for sustainable food, high energy forage, biofuel and biomaterial applications. © 2013 CSIRO. Plant Biotechnology Journal published by Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Anabaena sp. strain PCC 7120 conR contains a LytR-CpsA-Psr domain, is developmentally regulated, and is essential for diazotrophic growth and heterocyst morphogenesis.

PubMed

Mella-Herrera, Rodrigo A; Neunuebel, M Ramona; Golden, James W

2011-03-01

The conR (all0187) gene of the filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 is predicted to be part of a family of proteins that contain the LytR-CpsA-Psr domain associated with septum formation and cell wall maintenance. The conR gene was originally misannotated as a transcription regulator. Northern RNA blot analysis showed that conR expression was upregulated 8 h after nitrogen step-down. Fluorescence microscopy of a P(conR)-gfp reporter strain revealed increased GFP fluorescence in proheterocysts and heterocysts beginning 9 h after nitrogen step-down. Insertional inactivation of conR caused a septum-formation defect of vegetative cells grown in nitrate-containing medium. In nitrate-free medium, mutant filaments formed abnormally long heterocysts and were defective for diazotrophic growth. Septum formation between heterocysts and adjacent vegetative cells was abnormal, often with one or both poles of the heterocysts appearing partially open. In a conR mutant, expression of nifH was delayed after nitrogen step-down and nitrogenase activity was approximately 70 % of wild-type activity, indicating that heterocysts of the conR mutant strain are partially functional. We hypothesize that the diazotrophic growth defect is caused by an inability of the heterocysts to transport fixed nitrogen to the neighbouring vegetative cells.

Consumer Acceptance Comparison Between Seasoned and Unseasoned Vegetables

PubMed Central

Feng, Yiming; Albiol Tapia, Marta; Okada, Kyle; Castaneda Lazo, Nuria Blanca; Chapman‐Novakofski, Karen; Phillips, Carter

2018-01-01

Abstract Recent findings show that approximately 87% of the U.S. population fail to meet the vegetable intake recommendations, with unpleasant taste of vegetables being listed as the primary reason for this shortfall. In this study, spice and herb seasoning was used to enhance palatability of vegetables, in order to increase consumer acceptance. In total, 749 panelists were screened and recruited as specific vegetable likers of the vegetable being tested or general vegetable likers. Four sessions were designed to evaluate the effect of seasoning within each type of vegetable, including broccoli, cauliflower, carrot, and green bean. Each panelist was only allowed to participate in one test session to evaluate only one vegetable type, so as to mitigate potential learning effect. Overall, the results showed that seasoned vegetables were significantly preferred over unseasoned vegetables (P < 0.001), indicating the sensory properties were significantly improved with seasoning. When general vegetable likers and specific vegetable likers were compared in terms of their preference between seasoned and unseasoned vegetables, the pattern varied across different vegetables; however, general trend of seasoned vegetable being preferred remained. The findings from this study demonstrate the effect of seasoning in enhancing consumer liking of vegetables, which may lead to increased consumption to be assessed in future studies. Practical Application To improve the sensory properties of vegetables, masking the bitter taste of vegetables using spice and herb seasoning are gaining increasing attention. Our findings suggest that the overall liking of vegetables could be improved by incorporating spice and herb seasonings that are specifically formulated for each vegetable. Ultimately, developing and commercializing spice and herb seasonings may aid to increase vegetable consumption, as well as expanding the vegetable seasoning market. PMID:29337353

Consumer Acceptance Comparison Between Seasoned and Unseasoned Vegetables.

PubMed

Feng, Yiming; Albiol Tapia, Marta; Okada, Kyle; Castaneda Lazo, Nuria Blanca; Chapman-Novakofski, Karen; Phillips, Carter; Lee, Soo-Yeun

2018-02-01

Recent findings show that approximately 87% of the U.S. population fail to meet the vegetable intake recommendations, with unpleasant taste of vegetables being listed as the primary reason for this shortfall. In this study, spice and herb seasoning was used to enhance palatability of vegetables, in order to increase consumer acceptance. In total, 749 panelists were screened and recruited as specific vegetable likers of the vegetable being tested or general vegetable likers. Four sessions were designed to evaluate the effect of seasoning within each type of vegetable, including broccoli, cauliflower, carrot, and green bean. Each panelist was only allowed to participate in one test session to evaluate only one vegetable type, so as to mitigate potential learning effect. Overall, the results showed that seasoned vegetables were significantly preferred over unseasoned vegetables (P < 0.001), indicating the sensory properties were significantly improved with seasoning. When general vegetable likers and specific vegetable likers were compared in terms of their preference between seasoned and unseasoned vegetables, the pattern varied across different vegetables; however, general trend of seasoned vegetable being preferred remained. The findings from this study demonstrate the effect of seasoning in enhancing consumer liking of vegetables, which may lead to increased consumption to be assessed in future studies. To improve the sensory properties of vegetables, masking the bitter taste of vegetables using spice and herb seasoning are gaining increasing attention. Our findings suggest that the overall liking of vegetables could be improved by incorporating spice and herb seasonings that are specifically formulated for each vegetable. Ultimately, developing and commercializing spice and herb seasonings may aid to increase vegetable consumption, as well as expanding the vegetable seasoning market. © 2018 The Authors Journal of Food Science published by Wiley Periodicals, Inc. on behalf of Institute of Food Technologists.

Vegetation and the importance of insecticide-treated target siting for control of Glossina fuscipes fuscipes.

PubMed

Esterhuizen, Johan; Njiru, Basilio; Vale, Glyn A; Lehane, Michael J; Torr, Stephen J

2011-09-01

Control of tsetse flies using insecticide-treated targets is often hampered by vegetation re-growth and encroachment which obscures a target and renders it less effective. Potentially this is of particular concern for the newly developed small targets (0.25 high × 0.5 m wide) which show promise for cost-efficient control of Palpalis group tsetse flies. Consequently the performance of a small target was investigated for Glossina fuscipes fuscipes in Kenya, when the target was obscured following the placement of vegetation to simulate various degrees of natural bush encroachment. Catches decreased significantly only when the target was obscured by more than 80%. Even if a small target is underneath a very low overhanging bush (0.5 m above ground), the numbers of G. f. fuscipes decreased by only about 30% compared to a target in the open. We show that the efficiency of the small targets, even in small (1 m diameter) clearings, is largely uncompromised by vegetation re-growth because G. f. fuscipes readily enter between and under vegetation. The essential characteristic is that there should be some openings between vegetation. This implies that for this important vector of HAT, and possibly other Palpalis group flies, a smaller initial clearance zone around targets can be made and longer interval between site maintenance visits is possible both of which will result in cost savings for large scale operations. We also investigated and discuss other site features e.g. large solid objects and position in relation to the water's edge in terms of the efficacy of the small targets.

Selection of forest canopy gaps by male Cerulean Warblers in West Virginia

USGS Publications Warehouse

Perkins, Kelly A.; Wood, Petra Bohall

2014-01-01

Forest openings, or canopy gaps, are an important resource for many forest songbirds, such as Cerulean Warblers (Setophaga cerulea). We examined canopy gap selection by this declining species to determine if male Cerulean Warblers selected particular sizes, vegetative heights, or types of gaps. We tested whether these parameters differed among territories, territory core areas, and randomly-placed sample plots. We used enhanced territory mapping techniques (burst sampling) to define habitat use within the territory. Canopy gap densities were higher within core areas of territories than within territories or random plots, indicating that Cerulean Warblers selected habitat within their territories with the highest gap densities. Selection of regenerating gaps with woody vegetation >12 m within the gap, and canopy heights >24 m surrounding the gap, occurred within territory core areas. These findings differed between two sites indicating that gap selection may vary based on forest structure. Differences were also found regarding the placement of territories with respect to gaps. Larger gaps, such as wildlife food plots, were located on the periphery of territories more often than other types and sizes of gaps, while smaller gaps, such as treefalls, were located within territory boundaries more often than expected. The creations of smaller canopy gaps, <100 m2, within dense stands are likely compatible with forest management for this species.

A study to explore the use of orbital remote sensing to determine native arid plant distribution. [Arizona Regional Ecological Test Site

NASA Technical Reports Server (NTRS)

Mcginnies, W. G. (Principal Investigator); Lepley, L. K.; Haase, E. F.; Conn, J. S.; Musick, H. B.; Foster, K. E.

1974-01-01

The author has identified the following significant results. It is possible to determine, from ERTS imagery, native arid plant distribution. Using techniques of multispectral masking and extensive fieldwork, three native vegetation communities were defined and mapped in the Avra Valley study area. A map was made of the Yuma area with the aid of ground truth correlations between areas of desert pavement visible on ERTS images and unique vegetation types. With the exception of the Yuma soil-vegetation correlation phenomena, only very gross differentiations of desert vegetation communities can be made from ERTS data. Vegetation communities with obvious vegetation density differences such as saguaro-paloverde, creosote bush, and riparian vegetation can be separated on the Avra Valley imagery while more similar communities such as creosote bush and saltbush could not be differentiated. It is suggested that large differences in vegetation density are needed before the signatures of two different vegetation types can be differentiated on ERTS imagery. This is due to the relatively insignificant contribution of vegetation to the total radiometric signature of a given desert scene. Where more detailed information concerning the vegetation of arid regions is required, large scale imagery is appropriate.

247. Axial Parkway alignment along ridge top. Note the open ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

247. Axial Parkway alignment along ridge top. Note the open vistas to either side of the roadway. These are maintained through vegetation management. The wood guide rail is a primary safety feature. View is to the northeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

Restoration of temperate savannas and woodlands [Chapter 11

Treesearch

Brice B. Hanberry; John M. Kabrick; Peter W. Dunwiddie; Tibor Hartel; Theresa B. Jain; Benjamin O. Knapp

2017-01-01

Savannas and woodlands are open forest phases that occur along a gradient between grasslands and closed canopy forests. These ecosystems are characterized by open to nearly closed canopies of overstorey trees, relatively sparse midstorey and understorey woody vegetation, and dense, species-rich ground flora. In contrast to closed forests, the dominant and codominant...

Variation in selection of microhabitats by Merriam's turkey brood hens

Treesearch

Mark A. Rumble; Stanley H. Anderson

1997-01-01

We studied microhabitats of Merriam‘s turkey (Meleagris gallopavo merriami) brood hens in a ponderosa pine (Pinus ponderosa) ecosystem in South Dakota from 1986 to 1988. Cluster analysis indicated three groups of microhabitats, open-shrub, open-grasslforb and forest, based on vegetation characteristics at sites selected by brood...

Air pollution source apportionment before, during, and after the 2008 Beijing Olympics and association of sources to aldehydes and biomarkers of blood coagulation, pulmonary and systemic inflammation, and oxidative stress in healthy young adults

NASA Astrophysics Data System (ADS)

Altemose, Brent A.

Based on principal component analysis (PCA) of air pollution data collected during the Summer Olympic Games held in Beijing, China during 2008, the five source types of air pollution identified -- natural soil/road dust, vehicle and industrial combustion, vegetative burning, oil combustion, and secondary formation, were all distinctly lower during the Olympics. This was particularly true for vehicle and industrial combustion and oil combustion, and during the main games period between the opening and closing ceremonies. The reduction in secondary formation was reflective of a reduction in nitrogen oxides, but this also contributed to increased ozone concentrations during the Olympic period. Among three toxic aldehydes measured in Beijing during the same time period, only acetaldehyde had a reduction in mean concentration during the Olympic air pollution control period compared to the pre-Olympic period. Accordingly, acetaldehyde was significantly correlated with primary emission sources including vegetative burning and oil combustion, and with several pollutants emitted mainly from primary sources. In contrast, formaldehyde and acrolein increased during the Olympic air pollution control period; accordingly both were significantly correlated with ozone and with the secondary formation source type. These findings indicate primary sources may dominate for acetaldehyde while secondary sources may dominate for formaldehyde and acrolein. Biomarkers for pulmonary inflammation (exhaled breath condensate (EBC) pH, exhaled nitric oxide, and EBC nitrite) and hemostasis and blood coagulation (vWF and sCD62p) were most consistently associated with vehicle and industrial combustion, oil combustion, and vegetative burning. The systemic inflammation biomarker 8-OHdG was most consistently associated with vehicle and industrial combustion. In contrast, the associations between the biomarkers and the aldehydes were generally not significant or in the hypothesized direction, although EBC nitrite was associated with both acrolein and acetaldehyde, and sCD62p was associated with acetaldehyde. Notably, the biomarker sCD40L showed few significant associations with any of the air pollution source types or aldehydes. The findings indicate that implementing controls for combustion sources may have a positive impact on cardiorespiratory health, even in healthy young adults. More aggressive control of vegetative burning and further reduction of nitrogen oxide concentrations would likely have an even more positive impact.

Influence of open vegetation fires on black carbon and ozone variability in the southern Himalayas (NCO-P, 5079 m a.s.l.).

PubMed

Putero, D; Landi, T C; Cristofanelli, P; Marinoni, A; Laj, P; Duchi, R; Calzolari, F; Verza, G P; Bonasoni, P

2014-01-01

We analysed the variability of equivalent black carbon (BC) and ozone (O3) at the global WMO/GAW station Nepal Climate Observatory-Pyramid (NCO-P, 5079 m a.s.l.) in the southern Himalayas, for evaluating the possible contribution of open vegetation fires to the variability of these short-lived climate forcers/pollutants (SLCF/SLCP) in the Himalayan region. We found that 162 days (9% of the data-set) were characterised by acute pollution events with enhanced BC and O3 in respect to the climatological values. By using satellite observations (MODIS fire products and the USGS Land Use Cover Characterization) and air mass back-trajectories, we deduced that 56% of these events were likely to be affected by emissions from open fires along the Himalayas foothills, the Indian Subcontinent and the Northern Indo-Gangetic Plain. These results suggest that open fire emissions are likely to play an important role in modulating seasonal and inter-annual BC and O3 variability over south Himalayas. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Early Miocene Critical Zone at Karungu, Western Kenya: An Equatorial, Open Habitat with Few Primate Remains

NASA Astrophysics Data System (ADS)

Lukens, William E.; Lehmann, Thomas; Peppe, Daniel J.; Fox, David L.; Driese, Steven G.; McNulty, Kieran P.

2017-10-01

Early Miocene outcrops near Karungu, Western Kenya, preserve a range of fluvio-lacustrine, lowland landscapes that contain abundant fossils of terrestrial and aquatic vertebrates. Primates are notably rare among these remains, although nearby early Miocene strata on Rusinga Island contain a rich assemblage of fossilized catarrhines and strepsirrhines. To explore possible environmental controls on the occurrence of early Miocene primates, we performed a deep-time Critical Zone (DTCZ) reconstruction focused on floodplain paleosols at the Ngira locality in Karungu. We specifically focused on a single stratigraphic unit (NG15), which preserves moderately developed paleosols that contain a microvertebrate fossil assemblage. Although similarities between deposits at Karungu and Rusinga Island are commonly assumed, physical sedimentary processes, vegetative cover, soil hydrology, and some aspects of climate state are notably different between the two areas. Estimates of paleoclimate parameters using paleosol B horizon elemental chemistry and morphologic properties are consistent with seasonal, dry subhumid conditions, occasional waterlogging, and herbaceous vegetation. The reconstructed small mammal community indicates periodic waterlogging and open-canopy conditions. Based on the presence of herbaceous root traces, abundant microcharcoal, and pedogenic carbonates with high stable carbon isotope ratios, we interpret NG15 to have formed under a warm, seasonally dry, open riparian woodland to wooded grassland, in which at least a subset of the vegetation was likely C4 biomass. Our results, coupled with previous paleoenvironmental interpretations for deposits on Rusinga Island, demonstrate that there was considerable environmental heterogeneity ranging from open to closed habitats in the early Miocene. We hypothesize that the relative paucity of primates at Karungu was driven by their environmental preference for locally abundant closed canopy vegetation, which was likely absent at Karungu, at least during the NG15 interval if not also earlier and later intervals that have not yet been studied in as much detail.

Changes in riparian vegetation buffers in response to development in three Oregon cities

Treesearch

J. A. Yeakley; C. P. Ozawa; A. M. Hook

2006-01-01

Riparian vegetation buffer loss was investigated for three cities with contrasting local regulatory controls in urbanizing northwest Oregon. The cities examined were Hillsboro, Oregon City and Portland, all having experienced high rates of population increase in the 1990s. All cities are covered under Oregon’s land use law that provides goals for the protection of open...

Diversity, density, and development of early vegetation in a small clear-cut environment

Treesearch

Philip M. McDonald

1999-01-01

On a high quality site in northern California, frequency, density, foliar cover, and height were measured on every plant species present in an 8-acre clear-cut opening each year from 1976 through 1980. Plant species numbered 71, although no more than 62 were present during a given year. Categories of vegetation with the most plants per acre initially were shrubs,...

Spatial and temporal variation in soil and vegetation impacts on campsites

Treesearch

Jeffrey L. Marion; David N. Cole

1996-01-01

We studied the impacts of camping on soil and vegetation at Delaware Water Gap National Recreation Area. We assessed the magnitude of impact on campsites that varied in amount of use and in topographic position. We also evaluated change over a 5-yr period on long-established, recently opened, and recently closed campsites, as well as on plots subjected to experimental...

VegScape: U.S. Crop Condition Monitoring Service

NASA Astrophysics Data System (ADS)

mueller, R.; Yang, Z.; Di, L.

2013-12-01

Since 1995, the US Department of Agriculture (USDA)/National Agricultural Statistics Service (NASS) has provided qualitative biweekly vegetation condition indices to USDA policymakers and the public on a weekly basis during the growing season. Vegetation indices have proven useful for assessing crop condition and identifying the areal extent of floods, drought, major weather anomalies, and vulnerabilities of early/late season crops. With growing emphasis on more extreme weather events and food security issues rising to the forefront of national interest, a new vegetation condition monitoring system was developed. The new vegetation condition portal named VegScape was initiated at the start of the 2013 growing season. VegScape delivers web mapping service based interactive vegetation indices. Users can use an interactive map to explore, query and disseminate current crop conditions. Vegetation indices like Normal Difference Vegetation Index (NDVI), Vegetation Condition Index (VCI), and mean, median, and ratio comparisons to prior years can be constructed for analytical purposes and on-demand crop statistics. The NASA MODIS satellite with 250 meter (15 acres) resolution and thirteen years of data history provides improved spatial and temporal resolutions and delivers improved detailed timely (i.e., daily) crop specific condition and dynamics. VegScape thus provides supplemental information to support NASS' weekly crop reports. VegScape delivers an agricultural cultivated crop mask and the most recent Cropland Data Layer (CDL) product to exploit the agricultural domain and visualize prior years' planted crops. Additionally, the data can be directly exported to Google Earth for web mashups or delivered via web mapping services for uses in other applications. VegScape supports the ethos of data democracy by providing free and open access to digital geospatial data layers using open geospatial standards, thereby supporting transparent and collaborative government initiatives. NASS developed VegScape in cooperation with the Center for Spatial Information Science and Systems, George Mason University, Fairfax, VA. VegScape Ratio to Median NDVI

Does consumption of leafy vegetables grown in peri-urban agriculture pose a risk to human health?

PubMed

Nabulo, G; Black, C R; Craigon, J; Young, S D

2012-03-01

Concentrations of potentially toxic elements were measured in soils and five contrasting tropical leafy vegetables grown in a replicated field trial at five contaminated urban agriculture sites in Kampala City, Uganda. Soil contamination at each site could be tentatively ascribed to known waste disposal practices. There was considerable variation in metal uptake between vegetable types. Washing leafy vegetables reduced chromium and lead concentrations but exogenous contamination of leaves also depended on vegetable type, with Gynandropsis gynandra L. showing a marked tendency to accumulate Pb and Cr. For the worst case scenario of children consuming unwashed vegetables, some metal 'hazard quotient' (HQ) limits (1.0) were violated at four of the five sites studied. For the 25 'site-vegetable' combinations assessed, the HQ for Pb exceeded 1.0 in 36% of cases. A vegetable-specific site screening tool based on soil extraction with 0.01 M CaCl(2) and extrapolation to provide HQ values was assessed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of the method of preparation for consumption on calcium retention, calcium:phosphorus ratio, nutrient density and recommended daily allowance in fourteen vegetables.

PubMed

Słupski, Jacek; Gębczyński, Piotr; Korus, Anna; Lisiewska, Zofia

2014-06-01

The aim of this work was to evaluate calcium retention in 14 species of vegetable (from four usable groups). The material investigated consisted of raw and boiled fresh vegetables and two types of frozen product prepared for consumption after 12-month storage: one traditionally produced; the other obtained using the modified method (convenience food). The highest calcium content was found in leafy vegetables, followed (in descending order) by leguminous, root and brassica vegetables. The proportion by weight of Ca to P was highest in leafy vegetables and decreased with calcium retention despite the fact that levels of phosphorus were highest in leguminous and lowest in leafy vegetables. The nutrient density (ND%) of calcium for adults exceeded 100 for each individual vegetable species. The recommended daily allowance (RDA) percentage value varied between 23.04 (kale) and 1.46 (white cauliflower). Of the three types of product, ND and RDA values were generally greater in the frozen convenience products.

[Fine root biomass and production of four vegetation types in Loess Plateau, China].

PubMed

Deng, Qiang; Li, Ting; Yuan, Zhi-You; Jiao, Feng

2014-11-01

Fine roots (≤ 2 mm) play a major role in biogeochemical cycling in ecosystems. By the methods of soil cores and ingrowth soil cores, we studied the biomass and annual production of fine roots in 0-40 cm soil layers of four main vegetation types, i. e. , Robinia pseudoacacia plantation, deciduous shrubs, abandoned grassland, and Artemisia desertorum community in Loess Plateau, China. The spatial patterns of fine root biomass and production were negatively associated with latitudes. The fine root biomass in the 0-40 cm soil layer was in the order of deciduous shrubs (220 g · m(-2)), R. pseudoacacia plantation (163 g · m(-2)), abandoned grassland (162 g · m(-2)) and A. desertorum community (79 g · m(-2)). The proportion of ≤ 1 mm fine root biomass (74.1%) in the 0-40 cm soil layer of abandoned grassland was significantly higher than those in the other three vegetation types. The fine root biomass of the four vegetation types was mainly distributed in the 0-10 cm soil layer and decreased with soil depth. The proportion of fine root biomass (44.1%) in the 0-10 cm soil layer of abandoned grassland was significantly higher than those in other three vegetation types. The fine root productions of four vegetation types were in the order of abandoned grassland (315 g · m(-2) · a(-1)) > deciduous shrubs (249 g · m(-2) a(-1)) > R. pseudoacacia plantation (219 g · m(-2) · a(-1)) > A. desertorum community (115 g · m(-2) · a(-1)), and mainly concentrated in the 0-10 cm top soil layer and decreased with the soil depth. The proportion of the annual production (40.4%) in the 0-10 cm soil layer was the highest in abandoned grassland. Fine roots of abandoned grassland turned over faster than those from the other three vegetation types.

Identification, definition and mapping of terrestrial ecosystems in interior Alaska

NASA Technical Reports Server (NTRS)

Anderson, J. H. (Principal Investigator)

1972-01-01

The author has identified the following significant results. A reconstituted color infrared image covering the western Seward Peninsula was used for identifying vegetation types by simple visual examination. The image was taken by ERTS-1 approximately 1120 hours on August 1, 1972. Seven major colors were identified. Four of these were matched with four units on existing vegetation maps: bright red - shrub thicket; light gray-red - upland tundra; medium gray-red - coastal wet tundra; gray - alpine barrens. In the bright red color, two phases, violet and orange, were recognized and tentatively ascribed to differences in species composition in the shrub thicket type. The three colors which had no map unit equivalents were interpreted as follows: pink - grassland tundra; dark gray-red - burn scars; light orange-red - senescent vegetation. It was concluded that the image provides a considerable amount of information regarding the distribution of vegetation types, even at so simple a leval of analysis. It was also concluded that sequential imagery of this type could provide useful information on vegetation fires and phenologic events.

Seasonal variations in phosphorus fractions in semiarid sandy soils under different vegetation types

Treesearch

Qiong Zhao; Dehui Zeng; Zhiping Fan; Zhanyuan Yu; Yalin Hu; Jianwei Zhang

2009-01-01

We investigated the seasonal patterns of soil phosphorus (P) fractions under five vegetation types – Ulmus macrocarpa savanna, grassland, Pinus sylvestris var. mongolica plantation, Pinus tabulaeformis plantation, and Populus simonii plantation ...

Chorological classification approach for species and ecosystem conservation practice

NASA Astrophysics Data System (ADS)

Rogova, T. V.; Kozevnikova, M. V.; Prokhorov, V. E.; Timofeeva, N. O.

2018-01-01

The habitat type allocation approach based on the EUNIS Habitat Classification and the JUICE version 7 software is used for the conservation of species and ecosystem biodiversity. Using the vegetation plots of the Vegetation Database of Tatarstan, included in the EVA (European Vegetation Archive) and GIVD (Global Index of Vegetation-plots Databases) types of habitats of dry meadows and steppes are distinguished by differing compositions of the leading families composing their flora - Asteraceae, Fabaceae, Poaceae and Rosaceae. E12a - Semi-dry perennial calcareous grassland, and E12b - Perennial calcareous grassland and basic steppes were identified. The selected group of relevés that do not correspond to any of the EUNIS types can be considered specific for ecotone forest-steppe landscapes of the southeast of the Republic of Tatarstan. In all types of studied habitats, rare and protected plant species are noted, most of which are South-East-European-Asian species.

Sediment and Vegetation Controls on Delta Channel Networks

NASA Astrophysics Data System (ADS)

Lauzon, R.; Murray, A. B.; Piliouras, A.; Kim, W.

2016-12-01

Numerous factors control the patterns of distributary channels formed on a delta, including water and sediment discharge, grain size, sea level rise rates, and vegetation type. In turn, these channel networks influence the shape and evolution of a delta, including what types of plant and animal life - such as humans - it can support. Previous fluvial modeling and flume experiments, outside of the delta context, have addressed how interactions between sediment and vegetation, through their influence on lateral transport of sediment, determine what type of channel networks develops. Similar interactions likely also shape delta flow patterns. Vegetation introduces cohesion, tending to reduce channel migration rates and strengthen existing channel banks, reinforcing existing channels and resulting in localized, relatively stable flow patterns. On the other hand, sediment transport processes can result in lateral migration and frequent switching of active channels, resulting in flow resembling that of a braided stream. While previous studies of deltas have indirectly explored the effects of vegetation through the introduction of cohesive sediment, we directly incorporate key effects of vegetation on flow and sediment transport into the delta-building model DeltaRCM to explore how these effects influence delta channel network formation. Model development is informed by laboratory flume experiments at UT Austin. Here we present initial results of experiments exploring the effects of sea level rise rate, sediment grain size, vegetation type, and vegetation growth rate on delta channel network morphology. These results support the hypothesis that the ability for lateral transport of sediment to occur plays a key role in determining the evolution of delta channel networks and delta morphology.

Indirect Short- and Long-Term Effects of Aboveground Invertebrate and Vertebrate Herbivores on Soil Microarthropod Communities

PubMed Central

Vandegehuchte, Martijn L.; Raschein, Ursina; Schütz, Martin; Gwiazdowicz, Dariusz J.; Risch, Anita C.

2015-01-01

Recognition is growing that besides ungulates, small vertebrate and invertebrate herbivores are important drivers of grassland functioning. Even though soil microarthropods play key roles in several soil processes, effects of herbivores—especially those of smaller body size—on their communities are not well understood. Therefore, we progressively excluded large, medium and small vertebrate and invertebrate herbivores for three growing seasons using size-selective fences in two vegetation types in subalpine grasslands; short-grass and tall-grass vegetation generated by high and low historical levels of ungulate grazing. Herbivore exclusions generally had few effects on microarthropod communities, but exclusion of all herbivore groups resulted in decreased total springtail and Poduromorpha richness compared with exclusion of only ungulates and medium-sized mammals, regardless of vegetation type. The tall-grass vegetation had a higher total springtail richness and mesostigmatid mite abundance than the short-grass vegetation and a different oribatid mite community composition. Although several biotic and abiotic variables differed between the exclusion treatments and vegetation types, effects on soil microarthropods were best explained by differences in nutrient and fibre content of the previous year’s vegetation, a proxy for litter quality, and to a lesser extent soil temperature. After three growing seasons, smaller herbivores had a stronger impact on these functionally important soil microarthropod communities than large herbivores. Over longer time-scales, however, large grazers created two different vegetation types and thereby influenced microarthropod communities bottom-up, e.g. by altering resource quality. Hence, both short- and long-term consequences of herbivory affected the structure of the soil microarthropod community. PMID:25738942

Relationships between vegetation and terrain variables in southeastern Arizona. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Mouat, D. A. (Principal Investigator)

1974-01-01

The author has identified the following significant results. Relationships were established between eight terrain variables and plant species and 31 vegetation types. Certain plant species are better than others for differentiating or discriminating groups of specified terrain variables. Certain terrain variables are better than others for differentiating or discriminating groups of vegetation types. Stepwise discriminant analysis was shown to be a useful tool in plant ecological studies.

A Comparison of AIS Data with Other Aircraft and Ground Data for the Geobotanical Discrimination of Rock Types in Southwest Oregon

NASA Technical Reports Server (NTRS)

Mouat, D. A.

1985-01-01

The use of remote sensing techniques for the geobotanical discrimination of rock types is predicated upon a number of factors. These include an understanding of vegetation response to environmental (especially geochemical) conditions, the establishment of correlations between those vegetation factors and environmental factors, and the use of appropriate remote sensing techniques to discriminate the vegetation.

Effects of salinity and flooding on post-hurricane regeneration potential in coastal wetland vegetation

USGS Publications Warehouse

Middleton, Beth A.

2016-01-01

CONCLUSIONS: Seed germination and subsequent seedling growth in coastal wetlands may in some cases be affected by salinity intrusion events even at low salinity levels (1 and 5 ppt). These results indicate that the potential is great for hurricanes to shift vegetation type in sensitive wetland types (e.g., maritime forest) if post-hurricane environments do not support the regeneration of extent vegetation.

Effect of Replacing Pork Fat with Vegetable Oils on Quality Properties of Emulsion-type Pork Sausages

PubMed Central

Lee, Hyun-Jin; Jung, Eun-Hee; Lee, Sang-Hwa; Kim, Jong-Hee; Lee, Jae-Joon; Choi, Yang-II

2015-01-01

This study was conducted to evaluate the quality properties of emulsion-type pork sausages when pork fat is replaced with vegetable oil mixtures during processing. Pork sausages were processed under six treatment conditions: T1 (20% pork fat), T2 (10% pork fat + 2% grape seed oil + 4% olive oil + 4% canola oil), T3 (4% grape seed oil + 16% canola oil), T4 (4% grape seed oil + 4% olive oil + 12% canola oil), T5 (4% grape seed oil + 8% olive oil + 8% canola oil), and T6 (4% grape seed oil + 12% olive oil + 4% canola oil). Proximate analysis showed significant (p<0.05) differences in the moisture, protein, and fat content among the emulsion-type pork sausages. Furthermore, replacement with vegetable oil mixtures significantly decreased the ash content (p<0.05), increased water-holding capacity in emulsion-type pork sausages. Also, cholesterol content in T6 was significantly lower than T2 (p<0.05). In the texture profile analysis, hardness and chewiness of emulsion-type pork sausages were significantly (p<0.05) decreased by vegetable oil mixtures replacement. On the contrary, cohesiveness and springiness in the T4 group were similar to those of group T1. The unsaturated fatty acid content in emulsion-type pork sausages was increased by vegetable oil mixtures replacement. Replacement of pork fat with mixed vegetable oils had no negative effects on the quality properties of emulsion-type pork sausages, and due to its reduced saturated fatty acid composition, the product had the quality characteristics of the healthy meat products desired by consumers. PMID:26761810

Assessing vulnerability to invasion by nonnative plant species at multiple spatial scales

USGS Publications Warehouse

Stohlgren, T.J.; Chong, G.W.; Schell, L.D.; Rimar, K.A.; Otsuki, Yuka; Lee, M.; Kalkhan, M.A.; Villa, C.A.

2002-01-01

Basic information on where nonnative plant species have successfully invaded is lacking. We assessed the vulnerability of 22 vegetation types (25 sets of four plots in nine study areas) to nonnative plant invasions in the north–central United States. In general, habitats with high native species richness were more heavily invaded than species-poor habitats, low-elevation areas were more invaded than high-elevation areas, and riparian zones were more invaded than nearby upland sites. For the 100 1000-m2 plots (across all vegetation types), 50% of the variation in nonnative species richness was explained by longitude, latitude, native plant species richness, soil total percentage nitrogen, and mean maximum July temperature (n = 100 plots; P < 0.001). At the vegetation-type scale (n = 25 sets of four 1000-m2 plots/type), 64% of the variation in nonnative species richness was explained by native plant species richness, elevation, and October to June precipitation (P < 0.001). The foliar cover of nonnative species (log) was strongly positively correlated with the nonnative species richness at the plot scale (r = 0.77, P < 0.001) and vegetation-type scale (r = 0.83, P < 0.001). We concluded that, at the vegetation-type and regional scales in the north–central United States, (1) vegetation types rich in native species are often highly vulnerable to invasion by nonnative plant species; (2) where several nonnative species become established, nonnative species cover can substantially increase; (3) the attributes that maintain high native plant species richness (high light, water, nitrogen, and temperatures) also help maintain nonnative plant species richness; and (4) more care must be taken to preserve native species diversity in highly vulnerable habitats.

Dynamics of population densities and vegetation associations of Anopheles albimanus larvae in a coastal area of southern Chiapas, Mexico.

PubMed

Rodríguez, A D; Rodríguez, M H; Meza, R A; Hernández, J E; Rejmankova, E; Savage, H M; Roberts, D R; Pope, K O; Legters, L

1993-03-01

Spatial and seasonal variations on Anopheles albimanus larval densities and their plant associations were investigated in larval habitats in southern Mexico between April 1989 and May 1990. Thirty-four plant groups were dominant in larval habitats. Dense larval populations were associated with 3 genera of plants, Cynodon, Echinocloa and Fimbristylis and no larvae were found in habitats with Salvinia and Rhizophora. Low significant positive or negative associations were documented with the other 12 plant genera. Larval habitats were classified according to the morphology of their dominant plants. Higher larval densities were observed in the groups characterized by relatively short emergent vegetation. The distribution of habitat-types within 5 identified vegetation units showed a significantly dependent relationship. For the entire study period, highest larval densities were detected in flooded pasture/grassland vegetation units. For all vegetation units, higher larval densities were found when the dominant plant type covered between 25-50% of the breeding site. The integration of data from habitat-types into vegetation units did not result in loss of information.

Surface pollen and its relationship to vegetation in the Zoige Basin, eastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Li, Furong; Zhao, Yan; Sun, Jinghui; Zhao, Wenwei; Guo, Xiaoli; Zhang, Ke

2011-09-01

We use a data set of 23 surface pollen samples from moss polsters in the Zoige Basin to explore the relationship between modern pollen assemblages and contemporary vegetation patterns. The surface pollen samples spanned four types of plant communities: Carex muliensis marsh, Stipa and Kobresia meadow, Carex-dominated forb meadow and Sibiraea angustata scrub. Principal-components analysis (PCA) was used to determine the relationships between modern pollen and vegetation and environmental variables. The results show that the pollen assemblages of surface moss samples generally reflect the features of the modern vegetation, basically similar in the vegetation types and the dominant genera; however, they don't show a very clear distinction between different communities. Our results also demonstrate that pollen representation of different families or genus varied. Some tree taxa, such as Pinus and Betula, and herb types, such as Artemisia are over-represented, while Asteraceae, Ranunculaceae and Cyperaceae are moderately represented, and Poaceae and Rosaceae are usually under-represented in our study region. PCA results indicate that the distribution of vegetation in the Zoige Basin is mainly controlled by precipitation and altitude.

Species Composition at the Sub-Meter Level in Discontinuous Permafrost in Subarctic Sweden

NASA Astrophysics Data System (ADS)

Anderson, S. M.; Palace, M. W.; Layne, M.; Varner, R. K.; Crill, P. M.

2013-12-01

Northern latitudes are experiencing rapid warming. Wetlands underlain by permafrost are particularly vulnerable to warming which results in changes in vegetative cover. Specific species have been associated with greenhouse gas emissions therefore knowledge of species compositional shift allows for the systematic change and quantification of emissions and changes in such emissions. Species composition varies on the sub-meter scale based on topography and other microsite environmental parameters. This complexity and the need to scale vegetation to the landscape level proves vital in our estimation of carbon dioxide (CO2) and methane (CH4) emissions and dynamics. Stordalen Mire (68°21'N, 18°49'E) in Abisko and is located at the edge of discontinuous permafrost zone. This provides a unique opportunity to analyze multiple vegetation communities in a close proximity. To do this, we randomly selected 25 1x1 meter plots that were representative of five major cover types: Semi-wet, wet, hummock, tall graminoid, and tall shrub. We used a quadrat with 64 sub plots and measured areal percent cover for 24 species. We collected ground based remote sensing (RS) at each plot to determine species composition using an ADC-lite (near infrared, red, green) and GoPro (red, blue, green). We normalized each image based on a Teflon white chip placed in each image. Textural analysis was conducted on each image for entropy, angular second momentum, and lacunarity. A logistic regression was developed to examine vegetation cover types and remote sensing parameters. We used a multiple linear regression using forwards stepwise variable selection. We found statistical difference in species composition and diversity indices between vegetation cover types. In addition, we were able to build regression model to significantly estimate vegetation cover type as well as percent cover for specific key vegetative species. This ground-based remote sensing allows for quick quantification of vegetation cover and species and also provides the framework for scaling to satellite image data to estimate species composition and shift on the landscape level. To determine diversity within our plots we calculated species richness and Shannon Index. We found that there were statistically different species composition within each vegetation cover type and also determined which species were indicative for cover type. Our logistical regression was able to significantly classify vegetation cover types based on RS parameters. Our multiple regression analysis indicated Betunla nana (Dwarf Birch) (r2= .48, p=<0.0001) and Sphagnum (r2=0.59, p=<0.0001) were statistically significant with respect to RS parameters. We suggest that ground based remote sensing methods may provide a unique and efficient method to quantify vegetation across the landscape in northern latitude wetlands.

Vegetable variety: an effective strategy to increase vegetable intake in adults

PubMed Central

Meengs, Jennifer S.; Roe, Liane S.; Rolls, Barbara J.

2012-01-01

Effective strategies are needed to increase vegetable intake in accordance with health recommendations. Previous research has shown that increasing the variety of foods leads to increased consumption, yet this strategy has not been investigated for promoting vegetable intake. This cross-over study tested whether filling half the plate with a variety of vegetables influences vegetable consumption and meal energy intake. Once a week for 4 weeks, a meal of pasta and cooked vegetables was consumed ad libitum by 66 adults (34 women; 32 men). The meals were varied in the type of vegetables offered; at three meals 600 g of a single vegetable was served (broccoli, carrots, or snap peas) and at one meal 200 g of each of the three vegetables was served side by side. The experiment was conducted in 2008 and 2009 and data were analyzed using a mixed linear model with repeated measures. The results showed that serving a variety of vegetables increased vegetable intake at the meal (P<0.0001). Subjects ate more vegetables when served the variety than when served any single type; the mean increase was 48±6 g, or more than one-half serving. This increase remained significant when intake of the variety of vegetables was compared to the preferred vegetable of each participant (mean 25±8 g; P=0.002). Vegetable intake was not significantly related to energy intake at the meal. The results of this study demonstrate that increasing the variety of low-energy-dense vegetables served at a meal can be used as a strategy to increase vegetable intake. PMID:22818729

Dynamics of the recovery of damaged tundra vegetation: preliminary results of revegetation experiments of maritime tundra with Elymus mollis on Adak Island, Alaska. Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amundsen, C C; McCord, R A

1982-08-01

The vegetation of the central Aleutian Islands, Alaska is maritime tundra (Amundsen, 1977). While maritime tundra is not characterized by the presence of permafrost, the soil temperatures remain low (5 to 7/sup 0/C) year-round (Williams, 1980). The low soil temperature, a high level of soil moisture, and a low level of incident solar radiation are thought to delay the development of the vegetation. Natural revegetation of natural or man made open areas is relatively slow. Disturbed areas from World War II military activity are not completely revegetated after almost 40 years. Because of the windy and wet climate of themore » region, exposed soil is unstable and subject to extensive freeze-thaw action and erosion. Insults to the vegetation, both marine and aeolian, are common. Successful reproduction by seed is uncommon among species of this flora. The primary means of reproduction appears to be by vegetative propagules which are usually fragments of the shoot and rhizome. While the transport of the fragments by wind and water aids in the dispersal of the propagules, the same action often removes these fragments from open areas. This later activity further delays the revegetation of open and disturbed areas. Elymus mollis Trin. is the most successful major native species found to date as it fragments due to wind and water action and transplants easily. Transplanting experiments with sprigs of Elymus mollis Trin. have been conducted on Adak Island, Alaska since 1977. Preliminary results indicate that Elymus mollis may be transplanted for revegetation with a survival rate of at least 90 percent. Experiments were set up in 1979 to determine appropriate planting density, sprig rhizome length, and best time of year for transplanting. Preliminary results for these experiments are reported here.« less

Effect of temporary open-air markets on the sound environment and acoustic perception based on the crowd density characteristics.

PubMed

Meng, Qi; Sun, Yang; Kang, Jian

2017-12-01

The sound environment and acoustic perception of open-air markets, which are very common in high-density urban open spaces, play important roles in terms of the urban soundscape. Based on objective and subjective measurements of a typical temporary open-air market in Harbin city, China, the effects of the temporary open-air market on the sound environment and acoustic perception were studied, considering different crowd densities. It was observed that a temporary open-air market without zoning increases the sound pressure level and subjective loudness by 2.4dBA and 0.21dBA, respectively, compared to the absence of a temporary market. Different from the sound pressure level and subjective loudness, the relationship between crowd density and the perceived acoustic comfort is parabolic. Regarding the effect of a temporary open-air market with different zones on the sound environment and acoustic perception, when the crowd densities were the same, subjective loudness in the fruit and vegetable sales area was always higher than in the food sales area and the clothing sales area. In terms of acoustic comfort, with an increase in crowd density, acoustic comfort in the fruit and vegetable sales area decreased, and acoustic comfort in the food sales area and the clothing sales area exhibited a parabolic change trend of increase followed by decrease. Overall, acoustic comfort can be effectively improved by better planning temporary open-air markets in high-density urban open spaces. Copyright © 2017 Elsevier B.V. All rights reserved.

Native American impacts on fire regimes of the California coastal ranges

USGS Publications Warehouse

Keeley, Jon E.

2002-01-01

Aim: Native American burning impacts on California shrubland dominated landscapes are evaluated relative to the natural lightning fire potential for affecting landscape patterns. Location: Focus was on the coastal ranges of central and southern California. Methods: Potential patterns of Indian burning were evaluated based upon historical documents, ethnographic accounts, archaeological records and consideration of contemporary land management tactics. Patterns of vegetation distribution in this region were evaluated relative to environmental factors and the resilience of the dominant shrub vegetation to different fire frequencies. Results: Lightning fire frequency in this region is one of the lowest in North America and the density of pre-Columbian populations was one of the highest. Shrublands dominate the landscape throughout most of the region. These woody communities have weak resilience to high fire frequency and are readily displaced by annual grasses and forbs under high fire frequency. Intact shrublands provided limited resources for native Americans and thus there was ample motivation for using fire to degrade this vegetation to an open mosaic of shrubland/grassland, not unlike the agropastoral modification of ecologically related shrublands by Holocene peoples in the Mediterranean Basin. Alien-dominated grasslands currently cover approximately one-quarter of the landscape and less than 1% of these grasslands have a significant native grass presence. Ecological studies in the Californian coastal ranges have failed to uncover any clear soil or climate factors explaining grassland and shrubland distribution patterns. Main conclusions: Coastal ranges of California were regions of high Indian density and low frequency of lightning fires. The natural vegetation dominants on this landscape are shrubland vegetation that often form dense impenetrable stands with limited resources for Native Americans. Natural fire frequencies are not high enough to maintain these landscapes in habitable mixtures of shrublands and grasslands but such landscape mosaics are readily produced with additional human subsidy of ignitions. It is hypothesized that a substantial fraction of the landscape was type converted from shrubland to grassland and much of the landscape that underwent such type conversion has either been maintained by Euro-American land management practices or resisted recolonization of native shrublands. It appears that these patterns are disturbance dependent and result from anthropogenic alteration of landscapes initiated by Native Americans and sustained and expanded upon by Euro-American settlers.

Retrieval of seasonal dynamics of forest understory reflectance from semi-arid to boreal forests using MODIS BRDF data

NASA Astrophysics Data System (ADS)

Pisek, Jan; Chen, Jing; Kobayashi, Hideki; Rautiainen, Miina; Schaepman, Michael; Karnieli, Arnon; Sprintsin, Michael; Ryu, Youngryel; Nikopensius, Maris; Raabe, Kairi

2016-04-01

Ground vegetation (understory) provides an essential contribution to the whole-stand reflectance signal in many boreal, sub-boreal, and temperate forests. Accurate knowledge about forest understory reflectance is urgently needed in various forest reflectance modelling efforts. However, systematic collections of understory reflectance data covering different sites and ecosystems are almost missing. Measurement of understory reflectance is a real challenge because of an extremely high variability of irradiance at the forest floor, weak signal in some parts of the spectrum, spectral separability issues of over- and understory and its variable nature. Understory can consist of several sub-layers (regenerated tree, shrub, grasses or dwarf shrub, mosses, lichens, litter, bare soil), it has spatially-temporally variable species composition and ground coverage. Additional challenges are introduced by patchiness of ground vegetation, ground surface roughness, and understory-overstory relations. Due to this variability, remote sensing might be the only means to provide consistent data at spatially relevant scales. In this presentation, we report on retrieving seasonal courses of understory Normalized Difference Vegetation Index (NDVI) from multi-angular MODIS BRDF/Albedo data. We compared satellite-based seasonal courses of understory NDVI against an extended collection of different types of forest sites with available in-situ understory reflectance measurements. These sites are distributed along a wide latitudinal gradient on the Northern hemisphere: a sparse and dense black spruce forests in Alaska and Canada, a northern European boreal forest in Finland, hemiboreal needleleaf and deciduous stands in Estonia, a mixed temperate forest in Switzerland, a cool temperate deciduous broadleaf forest in Korea, and a semi-arid pine plantation in Israel. Our results indicated the retrieval method performs well particularly over open forests of different types. We also demonstrated the limitations of the method for closed canopies, where the understory signal retrieval is much attenuated. The retrieval of understory signal can be used e.g. to improve the estimates of leaf area index (LAI), fAPAR in sparsely vegetated areas, and also to study the phenology of understory layer. Our results are particularly useful to producing Northern hemisphere maps of seasonal dynamics of forests, allowing to separately retrieve understory variability, being a main contributor to spring emergence and fall senescence uncertainty. The inclusion of understory variability in ecological models will ultimately improve prediction and forecast horizons of vegetation dynamics.

Review of antidiabetic fruits, vegetables, beverages, oils and spices commonly consumed in the diet.

PubMed

Beidokhti, Maliheh Najari; Jäger, Anna K

2017-04-06

Type 2 diabetes is the most common type of diabetes and its prevalence is rapidly increasing throughout the world. Modifications of lifestyle such as suitable diet and exercise programs along with pharmacotherapy and education of patients are beneficial therapies for patients with type 2 diabetes. The ethnopharmacological use of herbal medicines, many of them part of our diet as spices, vegetables and fruits, has been developed for the treatment of diabetes due to inexpensiveness, easy availability and few side effects. Our aim is to present a review for researchers who are interested in the biologically active dietary plants traditionally utilized in the treatment of diabetes. Information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed, Sci Finder and Cochrane. Common and scientific name of the fruits, vegetables, beverages, oils and spices and the words 'antidiabetic', 'hypoglycemic', 'anti-hyperglycemic', 'type 2 diabetes' were used as keywords for search. Certain fruits and vegetables are functional foods and their consumption reduces the incidence of type 2 diabetes. Hypoglycemic effects of fruits and vegetables may be due to their inducing nature on pancreatic β-cells for insulin secretion, or bioactive compounds such as flavonoids, alkaloids and anthocyanins, which act as insulin-like molecules or insulin secretagogues. This write-up covers hypoglycemic, anti-hyperglycemic and anti-diabetic activities of some dietary fruits, vegetables, beverages, oils and spices and their active hypoglycemic constituents. Including such plant species in the diet might improve management of type 2 diabetes. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

75 FR 62387 - Pesticide Product Registrations; Conditional Approval

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-08

... soil fumigant use on soil that will be used to grow fruiting vegetable (tomato, pepper, and eggplant... vegetable (tomato, pepper, and eggplant), cucurbit vegetable (cucumber, squash (all types), and melon (all...

Mapping black panthers: Macroecological modeling of melanism in leopards (Panthera pardus).

PubMed

da Silva, Lucas G; Kawanishi, Kae; Henschel, Philipp; Kittle, Andrew; Sanei, Arezoo; Reebin, Alexander; Miquelle, Dale; Stein, Andrew B; Watson, Anjali; Kekule, Laurence Bruce; Machado, Ricardo B; Eizirik, Eduardo

2017-01-01

The geographic distribution and habitat association of most mammalian polymorphic phenotypes are still poorly known, hampering assessments of their adaptive significance. Even in the case of the black panther, an iconic melanistic variant of the leopard (Panthera pardus), no map exists describing its distribution. We constructed a large database of verified records sampled across the species' range, and used it to map the geographic occurrence of melanism. We then estimated the potential distribution of melanistic and non-melanistic leopards using niche-modeling algorithms. The overall frequency of melanism was ca. 11%, with a significantly non-random spatial distribution. Distinct habitat types presented significantly different frequencies of melanism, which increased in Asian moist forests and approached zero across most open/dry biomes. Niche modeling indicated that the potential distributions of the two phenotypes were distinct, with significant differences in habitat suitability and rejection of niche equivalency between them. We conclude that melanism in leopards is strongly affected by natural selection, likely driven by efficacy of camouflage and/or thermoregulation in different habitats, along with an effect of moisture that goes beyond its influence on vegetation type. Our results support classical hypotheses of adaptive coloration in animals (e.g. Gloger's rule), and open up new avenues for in-depth evolutionary analyses of melanism in mammals.

Mapping black panthers: Macroecological modeling of melanism in leopards (Panthera pardus)

PubMed Central

da Silva, Lucas G.; Kawanishi, Kae; Henschel, Philipp; Kittle, Andrew; Sanei, Arezoo; Reebin, Alexander; Miquelle, Dale; Stein, Andrew B.; Watson, Anjali; Kekule, Laurence Bruce; Machado, Ricardo B.

2017-01-01

The geographic distribution and habitat association of most mammalian polymorphic phenotypes are still poorly known, hampering assessments of their adaptive significance. Even in the case of the black panther, an iconic melanistic variant of the leopard (Panthera pardus), no map exists describing its distribution. We constructed a large database of verified records sampled across the species’ range, and used it to map the geographic occurrence of melanism. We then estimated the potential distribution of melanistic and non-melanistic leopards using niche-modeling algorithms. The overall frequency of melanism was ca. 11%, with a significantly non-random spatial distribution. Distinct habitat types presented significantly different frequencies of melanism, which increased in Asian moist forests and approached zero across most open/dry biomes. Niche modeling indicated that the potential distributions of the two phenotypes were distinct, with significant differences in habitat suitability and rejection of niche equivalency between them. We conclude that melanism in leopards is strongly affected by natural selection, likely driven by efficacy of camouflage and/or thermoregulation in different habitats, along with an effect of moisture that goes beyond its influence on vegetation type. Our results support classical hypotheses of adaptive coloration in animals (e.g. Gloger’s rule), and open up new avenues for in-depth evolutionary analyses of melanism in mammals. PMID:28379961

Effects of total and green vegetable intakes on glycated hemoglobin A1c and triglycerides in elderly patients with type 2 diabetes mellitus: the Japanese Elderly Intervention Trial.

PubMed

Takahashi, Keiko; Kamada, Chiemi; Yoshimura, Hidenori; Okumura, Ryota; Iimuro, Satoshi; Ohashi, Yasuo; Araki, Atsushi; Umegaki, Hiroyuki; Sakurai, Takashi; Yoshimura, Yukio; Ito, Hideki

2012-04-01

Many reports have shown that vegetable intake is effective in inhibiting the onset and progression of diabetes mellitus, although the amount of vegetable intake required to be effective remains as unclear. The present study therefore aimed to clarify the relationship between the amount of vegetable intake and glycated hemoglobin A1c (HbA1c) and other metabolic parameters using male Japanese type 2 diabetic patients aged 65 years or older as subjects. Participants were 417 male type 2 diabetic patients aged 65 years or older enrolled in the Japanese Elderly Diabetes Intervention Trial. Dietary intakes were measured by using the Food Frequency Questionnaires method. The patients were divided into five groups by their daily total vegetable intake (A1: ~100 g, A2: 100~150 g, A3: 150~200 g, A4: 200~300 g, A5: 300 g~), and compared HbA1c and other metabolic parameters. Furthermore, the relationship between daily green vegetable intake and HbA1c and other metabolic parameters were examined among five groups divided by quintile methods. There were significant decreases in HbA1c, triglycerides and waist circumference with an increase of total vegetable intake. A significant decrease of HbA1c levels was observed in patients with a daily total vegetable intake of 150 g or more. Furthermore, there was a significant decrease of serum triglyceride levels in patients with a total vegetable intake of 200 g or more. HbA1c levels showed a decreasing tendency with the increase of green vegetable intake, and HbA1c levels in the Q1 group (green vegetable intake: less than 40 g) was significantly higher than those in the other four groups (anovaP = 0.025). In addition, there were significant decreases of body mass index, triglyceride levels and waist circumference with the increase of green vegetable intake. Triglyceride levels decreased significantly from the Q3 group (green vegetable intake: 70 g or more) to the Q5 group (green vegetable intake: 130 g or more; anovaP = 0.016). In the group with a lower intake of total vegetables and green vegetables, the protein energy ratio decreased significantly. As a result, the fat energy ratio and energy intake tended to increase with the decrease of total and green vegetable intakes. Furthermore, intake of grains, sweets and alcoholic beverages increased with the decrease of total vegetable intake. In contrast, intake of nuts, potatoes, sugar, legumes, fruit, seaweed and fish increased with the increase of total vegetable intake Daily total vegetable intake of 200 g or more, and green vegetable intake of 70 g or more correlated with improved control of HbA1c and triglyceride levels in elderly type 2 diabetes patients through achieving a well-balanced diet. © 2012 Japan Geriatrics Society.

Late Glacial Tropical Savannas in Sundaland Inferred From Stable Carbon Isotope Records of Cave Guano

NASA Astrophysics Data System (ADS)

Wurster, C. M.; Bird, M. I.; Bull, I.; Dungait, J.; Bryant, C. L.; Ertunç, T.; Hunt, C.; Lewis, H. A.; Paz, V.

2008-12-01

During the Last Glacial Period (LGP), reduced global sea level exposed the continental shelf south of Thailand to Sumatra, Java, and Borneo to form the contiguous continent of Sundaland. However, the type and extent of vegetation that existed on much of this exposed landmass during the LGP remains speculative. Extensive bird and bat guano deposits in caves throughout this region span beyond 40,000 yr BP, and contain a wealth of untapped stratigraphic palaeoenvironmental information. Stable carbon isotope ratios of insectivorous bird and bat guano contain a reliable record of the animal's diet and, through non-specific insect predation, reflect the relative abundance of major physiological pathways in plants. Various physiological pathways of carbon fixation in plants yield differing stable carbon isotope ratios. Stable carbon isotope values of C3 plants are lower than C4 vegetation due to different enzymatic discriminations of the heavy isotope through the carbon fixing pathways. In tropical locales, grasses nearly always follow the C4 photosynthetic pathway, whereas tropical rainforest uses C3 photosynthesis, providing a proxy for vegetation and therefore climate change in the past. Here we discuss four guano stable-isotope records, based on insect cuticle and n-alkane analysis, supplemented by pollen analysis. All sites suggest a C3 dominated ecosystem for the Holocene, consistent with the wet tropical forest vegetation present at all locations. Two sites from Palawan Island, Philippines, record stable carbon isotope values of guano that document a drastic change from C3 (forest) to C4 (savanna) dominated ecosystems during the Last Glacial Maximum (LGM). A third location, at Niah Great Cave, Malaysia, indicates C3-dominant vegetation throughout the record, but does display variation in stable carbon isotope values likely linked to humidity changes. A fourth location, Batu Caves in Peninsular Malaysia, also indicates open vegetation during the LGM. Vegetation models disagree as to the nature of vegetation during the LGM in Sundaland, but our results suggest major contraction of forest area with significant implications for carbon storage during the LGM and also for understanding the development of modern biogeographic and genetic patterns in the region. Additional cave guano sites will provide further constraints on the nature of environmental change in the region over the last glacial cycle.

A High Density Storm Surge Monitoring Network: Evaluating the Ability of Wetland Vegetation to Reduce Storm Surge

NASA Astrophysics Data System (ADS)

Lawler, S.; Denton, M.; Ferreira, C.

2013-12-01

Recent tropical storm activity in the Chesapeake Bay and a potential increase in the predicted frequency and magnitude of weather systems have drawn increased attention to the need for improved tools for monitoring, modeling and predicting the magnitude of storm surge, coastal flooding and the respective damage to infrastructure and wetland ecosystems. Among other forms of flood protection, it is believed that coastal wetlands and vegetation can act as a natural barrier that slows hurricane flooding, helping to reduce the impact of storm surge. However, quantifying the relationship between the physical process of storm surge and its attenuation by wetland vegetation is an active area of research and the deployment of in-situ measuring devices is crucial to data collection efforts in this field. The United States Geological Survey (USGS) mobile storm-surge network has already successfully provided a framework for evaluating hurricane induced storm surge water levels on a regional scale through the use of in-situ devices installed in areas affected by storm surge during extreme events. Based on the success of the USGS efforts, in this study we adapted the monitoring network to cover relatively small areas of wetlands and coastal vegetation with an increased density of sensors. Groups of 6 to 10 water level sensors were installed in sites strategically selected in three locations on the Virginia coast of the lower Chesapeake Bay area to monitor different types of vegetation and the resulting hydrodynamic patterns (open coast and inland waters). Each group of sensors recorded time series data of water levels for both astronomical tide circulation and meteorological induced surge. Field campaigns were carried out to survey characteristics of vegetation contributing to flow resistance (i.e. height, diameter and stem density) and mapped using high precision GPS. A geodatabase containing data from field campaigns will support the development and calibration of computational models to simulate storm surge flow over wetlands specifically designed to represent Virginia's aquatic vegetation and to improve our fundamental knowledge of tide and storm surge hydrodynamics in estuarine wetlands. This poster will present the results of the field measurements for events during the 2013 Hurricane Season, tidal flows within the study areas, and surge attenuation rates according to vegetation characteristics.

Processing Uav and LIDAR Point Clouds in Grass GIS

NASA Astrophysics Data System (ADS)

Petras, V.; Petrasova, A.; Jeziorska, J.; Mitasova, H.

2016-06-01

Today's methods of acquiring Earth surface data, namely lidar and unmanned aerial vehicle (UAV) imagery, non-selectively collect or generate large amounts of points. Point clouds from different sources vary in their properties such as number of returns, density, or quality. We present a set of tools with applications for different types of points clouds obtained by a lidar scanner, structure from motion technique (SfM), and a low-cost 3D scanner. To take advantage of the vertical structure of multiple return lidar point clouds, we demonstrate tools to process them using 3D raster techniques which allow, for example, the development of custom vegetation classification methods. Dense point clouds obtained from UAV imagery, often containing redundant points, can be decimated using various techniques before further processing. We implemented and compared several decimation techniques in regard to their performance and the final digital surface model (DSM). Finally, we will describe the processing of a point cloud from a low-cost 3D scanner, namely Microsoft Kinect, and its application for interaction with physical models. All the presented tools are open source and integrated in GRASS GIS, a multi-purpose open source GIS with remote sensing capabilities. The tools integrate with other open source projects, specifically Point Data Abstraction Library (PDAL), Point Cloud Library (PCL), and OpenKinect libfreenect2 library to benefit from the open source point cloud ecosystem. The implementation in GRASS GIS ensures long term maintenance and reproducibility by the scientific community but also by the original authors themselves.

Vegetative and geologic mapping of the western Seward Peninsula, Alaska, based on ERTS-1 imagery

NASA Technical Reports Server (NTRS)

Anderson, J. H.; Shapiro, L. H.; Belon, A. E.

1973-01-01

ERTS-1 scene 1009-22095 (Western Seward Peninsula, Alaska) has been studied, partly as a training exercise, to evaluate whether direct visual examination of individual and custom color-composite prints can provide new information on the vegetation and geology of this relatively well known area of Alaska. The vegetation analysis reveals seven major vegetation types, only four of which are described on existing vegetation maps. In addition, the ERTS analysis provides greater detail than the existing maps on the areal distribution of vegetation types. The geologic analysis demonstrates that most of the major rock units and geomorphic boundaries shown on the available geologic maps could also be identified on the ERTS data. Several major high-angle faults were observed, but the zones of thrust faults which are much less obvious.

Enhancing the open space of Jabodetabek area, Indonesia

NASA Astrophysics Data System (ADS)

Wartaman, A. S.; Situmorang, R.; Suharto, B. B.

2018-01-01

Jabodetabek area is planned to be developed as a sustainable development region. The Government of Indonesia (GoI) committed in Paris Conference that the target of GHG emissions would be reduced by 29% up to 2030 with her own efforts and by 41% with supported by international assistance. This research attempts to apply specific methods such as stratified planting method to improve the quality of green open space by increasing the absorbed carbon level. The study showed that with the planting vegetation of stratified model, the total capacity of the mainland to absorb CO2 gas is quite significant increase with approximately 20% compared to that of homogeneous vegetation. The stratified planting model is worthwhile to achieve the commitment of the GoI mentioned above.

Long-term monitoring of stream bank stability under different vegetation cover

NASA Astrophysics Data System (ADS)

Krzeminska, Dominika; Skaalsveen, Kamilla; Kerkhof, Tjibbe

2017-04-01

Vegetated buffer zones are common environmental measures in many countries, including Norway. The presence of riparian vegetation on stream banks not only provides ecological benefits but also influence bank slope stability, through several complex interactions between riparian vegetation and hydro - mechanical processes. The hydrological processes associated with slope stability are complex and yet difficult to quantify, especially because their transient effects (e.g. changes throughout the vegetation life cycle). Additionally, there is very limited amount of field scale research focusing on investigation of coupled hydrological and mechanical influence of vegetation on stream bank behavior, accounting for both seasonal time scale and different vegetation type, and none dedicated to marine clay soils (typically soil for Norway). In order to fill this gap we established continues, long term hydrogeological monitoring o selected cross - section within stream bank, covered with different types of vegetation, typical for Norwegian agriculture areas (grass, shrubs, and trees). The monitoring involves methods such as spatial and temporal monitoring of soil moisture conditions, ground water level and fluctuation of water level in the stream. Herein we will present first 10 months of monitoring data: observed hydrological trends and differences between three cross - sections. Moreover, we will present first modelling exercises that aims to estimate stream banks stability with accounting on presence of different vegetation types using BSTEM and HYDRUS models. With this presentation, we would like to stimulate the discussion and get feedback that could help us to improve both, our experimental set up and analysis approach.

Laboratory Evaluation of Australian Ration Packs

DTIC Science & Technology

1988-10-01

shortage of vitamin concentrates for fortification. Chicken & Vegetables, Beef Meatballs with Bacon & Vegetables and Lamb & Vegetables with Rosemary...MENU ITEM NAME Salt Salt % Salt of % Users* % g Ration responding Total "too salty" A Beef and Vegetables 1.2 2.7 15.5 Ham and Egg 1.5 1.7 10.0 TOTAL...1.4 6.2 Luncheon Meat Type 1 2.1 4.7 21.2 9 Beef Soup and Gravy Base 50.6 3.4 15.2 TOTAL 9.5 42.6 E Corned Beef Type E 2.6 5.7 25.4 15 Beef and Egg 1.1

Role of vegetation in interplay of climate, soil and groundwater recharge in a global dataset

NASA Astrophysics Data System (ADS)

Kim, J. H.; Jackson, R. B.

2010-12-01

Groundwater is an essential resource for people and ecosystems worldwide. Our capacity to ameliorate predicted global water shortages and to maintain sustainable water supplies depend on a better understanding of the controls of recharge and how vegetation change may affect recharge mechanisms. The goals of this study are to quantify the importance of vegetation as a dominant control on recharge globally and to compare the importance of vegetation with other hydrologically important variables, including climate and soil. We based our global analysis on > 500 recharge estimates from the literature that contained information on vegetation, soil and climate or location. Plant functional types significantly affected groundwater recharge rates substantially. After climatic factors (water inputs, PET, and seasonality), vegetation types explained about 15% of the residuals in the dataset. Across all climatic factors, croplands had the highest recharge rates, followed by grasslands, scrublands and woodlands (average recharge: 75, 63, 30, 22 mm/yr respectively). Recharge under woodlands showed the most nonlinear response to water inputs. Differences in recharge between the vegetation types were more exaggerated at arid climates and in clay soils, indicating greater biological control on soil water fluxes in these conditions. Our results shows that vegetation greatly affects recharge rates globally and alters relationship between recharge and physical variables allowing us to better predict recharge rates globally.

Increased wetness confounds Landsat-derived NDVI trends in the central Alaska North Slope region, 1985-2011

NASA Astrophysics Data System (ADS)

Raynolds, Martha K.; Walker, Donald A.

2016-08-01

Satellite data from the circumpolar Arctic have shown increases in vegetation indices correlated to warming air temperatures (e.g. Bhatt et al 2013 Remote Sensing 5 4229-54). However, more information is needed at finer scales to relate the satellite trends to vegetation changes on the ground. We examined changes using Landsat TM and ETM+ data between 1985 and 2011 in the central Alaska North Slope region, where the vegetation and landscapes are relatively well-known and mapped. We calculated trends in the normalized difference vegetation index (NDVI) and tasseled-cap transformation indices, and related them to high-resolution aerial photographs, ground studies, and vegetation maps. Significant, mostly negative, changes in NDVI occurred in 7.3% of the area, with greater change in aquatic and barren types. Large reflectance changes due to erosion, deposition and lake drainage were evident. Oil industry-related changes such as construction of artificial islands, roads, and gravel pads were also easily identified. Regional trends showed decreases in NDVI for most vegetation types, but increases in tasseled-cap greenness (56% of study area, greatest for vegetation types with high shrub cover) and tasseled-cap wetness (11% of area), consistent with documented degradation of polygon ice wedges, indicating that increasing cover of water may be masking increases in vegetation when summarized using the water-sensitive NDVI.

Assessment of patches attributes along the Urban Development Gradient

NASA Astrophysics Data System (ADS)

Kopel, Daniella; Wittenberg, lea; Malkinson, Dan

2014-05-01

The world is increasingly urban. If current trends maintain, by 2050 the global urban population is estimated to be 6.3 billion, nearly doubling the world population in 2010. Consequently, more than 60% of the area projected to be urban in 2030 has yet to be built, replacing the open and agriculture lands with construction and infrastructure. The open green patches (OGP), within the urban matrix, are essential for healthy and wellness of cities by supplying the city's ecological services (Mausback and Seybold, 1998). Regarding future trends, there is a need and obligation to insure the functional and sustainability of the city's OPG. Urban vegetation composition and diversity in the OGP had long been considered as an indication for ecologically functioning systems. Furthermore, urban soil is also essential for the sustainability and function of the urban habitat and ecological services, such as maintaining groundwater restraining urban floods etc. (Lehmann and Stahr 2007). There is no single set of rules to classify a functional urban green patch worth preserving. The aim of this study is to examine the effects of patch properties (including geometry, age, type and location along the urban gradient, connectivity, and urban matrix density) on the presence, abundance and characteristics of vegetation and soil conditions of remnant patches The inspired purpose is to eventually find an assessment for urban open green patches OGP quality by linking, patches attributes, plants indexes and soil quality indexes The research is conducted in the city of Haifa, which is located on the northern part of Mount Carmel in the north-western part of Israel . Mean annual rainfall, 550-800 mm, varies with latitude and the mean temperature is 18.80c. Modern Haifa is a relatively young city which maintains remnant vegetation patches within its municipal boundary. 32 OGP were selected in nine categories (size: small, medium and large, distance from city edge: far, average, near), in which vegetation was surveyed. . All vascular plant species were recorded and identified. The mineral soils (A horizon, depth 10-15 cm) were collected to obtain a constant sample size after removing surface litter and organic matter. The samples were analyzed for mineral and structure properties. Preliminary results of the plant survey and analysis indicated that the patches' vegetation is highly diverse. Within the large patches, regardless of their location along the urban development gradient, higher sub-habitat diversity and plants diversity were observed. The diversity is high for local and exotic species alike. In the medium and small size patches, also regardless of their location, there is a diversity of plant composition that may be connected to different disturbances or matrix related effect not yet considered in the study. Preliminary results of the soil survey and analysis indicated that more than 75% of the soil samples taken from the OGP, regardless of their location in the urban development gradient, exhibited a considerable changes in soil profile, compared to "natural" soils and significant alternations in the physical properties were also observed. The substance that was found in the remnant OGP in Haifa is different from soil, however, links between the urban-soils altered properties and the vegetation composition in those patches, and there relationships are not fully understood.

Mid Miocene Terrestrial Ecosystems: Information from Mammalian Herbivore Communities.

NASA Astrophysics Data System (ADS)

Janis, C. M.; Damuth, J.; Theodor, J. M.

2001-05-01

In present day ecosystems the numbers and proportions of different kinds of ecologically distinct ungulates (hoofed mammals) provide an indicator of the nature of the vegetation in the habitat. Different vegetation types (such as forest, savanna, or grassland) are characteristically associated with different arrays of ungulates, with species exhibiting differences in diet, body size, and type of digestive fermentation system. These biological attributes can also be inferred for fossil ungulate species, the first two from quantitative assessment of skull and dental anatomy, and the last from phylogenetic affinity. Thus fossil ungulate communities may be used as indicators of the vegetation types of the habitats in which they lived. Vegetation types, in turn, are determined largely by a number of physical environmental factors. Typical ungulate communities of the late early to early middle Miocene (17 - 15 Ma) from the Great Plains of North America contained a diversity of browsing (leaf-eating) and grazing (grass-eating) species, with proportions of dietary types and a diversity of body sizes indicative of a woodland savanna habitat. Paleobotanical evidence also indicates a woodland savanna type of vegetation. However, these communities included a much larger number of ungulate species than can be found in any present-day community. The "excess" ungulate species were primarily browsers. Throughout the rest of the middle Miocene both species numbers and the proportion of browsers in ungulate communities appear to have declined steadily. During this decline in browser species the numbers of grazer species remained relatively constant. Within-community species numbers comparable to the present day were attained by the late Miocene. We suggest that the early Miocene browser-rich communities, and their subsequent decline, carry an important paleoenvironmental signal. In particular, communities "over rich" in browsers may reflect higher levels of primary productivity in mid Miocene vegetation types in comparison with corresponding, structurally equivalent present-day vegetation types. The observed decline in species numbers may represent a gradual decline in terrestrial primary productivity, which would be consistent with one current hypothesis of a mid-Miocene decrease in atmospheric carbon dioxide concentrations from higher mid-Cenozoic values.

Mapping vegetation in Yellowstone National Park using spectral feature analysis of AVIRIS data

USGS Publications Warehouse

Kokaly, Raymond F.; Despain, Don G.; Clark, Roger N.; Livo, K. Eric

2003-01-01

Knowledge of the distribution of vegetation on the landscape can be used to investigate ecosystem functioning. The sizes and movements of animal populations can be linked to resources provided by different plant species. This paper demonstrates the application of imaging spectroscopy to the study of vegetation in Yellowstone National Park (Yellowstone) using spectral feature analysis of data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). AVIRIS data, acquired on August 7, 1996, were calibrated to surface reflectance using a radiative transfer model and field reflectance measurements of a ground calibration site. A spectral library of canopy reflectance signatures was created by averaging pixels of the calibrated AVIRIS data over areas of known forest and nonforest vegetation cover types in Yellowstone. Using continuum removal and least squares fitting algorithms in the US Geological Survey's Tetracorder expert system, the distributions of these vegetation types were determined by comparing the absorption features of vegetation in the spectral library with the spectra from the AVIRIS data. The 0.68 μm chlorophyll absorption feature and leaf water absorption features, centered near 0.98 and 1.20 μm, were analyzed. Nonforest cover types of sagebrush, grasslands, willows, sedges, and other wetland vegetation were mapped in the Lamar Valley of Yellowstone. Conifer cover types of lodgepole pine, whitebark pine, Douglas fir, and mixed Engelmann spruce/subalpine fir forests were spectrally discriminated and their distributions mapped in the AVIRIS images. In the Mount Washburn area of Yellowstone, a comparison of the AVIRIS map of forest cover types to a map derived from air photos resulted in an overall agreement of 74.1% (kappa statistic=0.62).

Structure, Function and Floristic Relationships of Plant Communities in Stressful Habitats Marginal to the Brazilian Atlantic Rainforest

PubMed Central

SCARANO, FABIO R.

2002-01-01

The Brazilian Atlantic rainforest consists of a typical tropical rainforest on mountain slopes, and stands out as a biodiversity hotspot for its high species richness and high level of species endemism. This forest is bordered by plant communities with lower species diversity, due mostly to more extreme environmental conditions than those found in the mesic rainforest. Between the mountain slopes and the sea, the coastal plains have swamp forests, dry semi‐deciduous forests and open thicket vegetation on marine sand deposits. At the other extreme, on top of the mountains (>2000 m a.s.l.), the rainforest is substituted by high altitude fields and open thicket vegetation on rocky outcrops. Thus, the plant communities that are marginal to the rainforest are subjected either to flooding, drought, oceanicity or cold winter temperatures. It was found that positive interactions among plants play an important role in the structuring and functioning of a swamp forest, a coastal sandy vegetation and a cold, high altitude vegetation in the state of Rio de Janeiro. Moreover, only a few species seem to adopt this positive role and, therefore, the functioning of these entire systems may rely on them. Curiously, these nurse plants are often epiphytes in the rainforest, and at the study sites are typically terrestrial. Many exhibit crassulacean acid metabolism. Conservation initiatives must treat the Atlantic coastal vegetation as a complex rather than a rainforest alone. PMID:12324276

Historical open forest ecosystems in the Missouri Ozarks: reconstruction and restoration targets

Treesearch

Brice B. Hanberry; D. Todd Jones-Farrand; John M. Kabrick

2014-01-01

Current forests no longer resemble historical open forest ecosystems in the eastern United States. In the absence of representative forest ecosystems under a continuous surface fire regime at a large scale, reconstruction of historical landscapes can provide a reference for restoration efforts. For initial expert-assigned vegetation phases ranging from prairie to...

Glacial-interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean

NASA Astrophysics Data System (ADS)

Dupont, L. M.; Caley, T.; Kim, J.-H.; Castañeda, I.; Malaizé, B.; Giraudeau, J.

2011-11-01

Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ∼120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka) have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome) for the last glacial as well as for other glacial periods of the past 300 Ka.

Effects of grazing on spatiotemporal variations in community structure and ecosystem function on the grasslands of Inner Mongolia, China.

PubMed

Su, Rina; Cheng, Junhui; Chen, Dima; Bai, Yongfei; Jin, Hua; Chao, Lumengqiqige; Wang, Zhijun; Li, Junqing

2017-02-28

Grasslands worldwide are suffering from overgrazing, which greatly alters plant community structure and ecosystem functioning. However, the general effects of grazing on community structure and ecosystem function at spatial and temporal scales has rarely been examined synchronously in the same grassland. Here, during 2011-2013, we investigated community structure (cover, height, and species richness) and aboveground biomass (AGB) using 250 paired field sites (grazed vs. fenced) across three vegetation types (meadow, typical, and desert steppes) on the Inner Mongolian Plateau. Grazing, vegetation type, and year all had significant effects on cover, height, species richness, and AGB, although the primary factor influencing variations in these variables was vegetation type. Spatially, grazing significantly reduced the measured variables in meadow and typical steppes, whereas no changes were observed in desert steppe. Temporally, both linear and quadratic relationships were detected between growing season precipitation and cover, height, richness, or AGB, although specific relationships varied among observation years and grazing treatments. In each vegetation type, the observed community properties were significantly correlated with each other, and the shape of the relationship was unaffected by grazing treatment. These findings indicate that vegetation type is the most important factor to be considered in grazing management for this semi-arid grassland.

Accuracy assessment of percent canopy cover, cover type, and size class

Treesearch

H. T. Schreuder; S. Bain; R. C. Czaplewski

2003-01-01

Truth for vegetation cover percent and type is obtained from very large-scale photography (VLSP), stand structure as measured by size classes, and vegetation types from a combination of VLSP and ground sampling. We recommend using the Kappa statistic with bootstrap confidence intervals for overall accuracy, and similarly bootstrap confidence intervals for percent...

The vegetative communities associated with mammals of the South. Chapter 2

Treesearch

Beverly Collins; Philip E. Hyatt; Margaret K. Trani

2007-01-01

This chapter describes the ecoregions and vegetation types associated with mammals of the South. The distribution of mammals in the South reflects historic biogeographical processes as well as physiography and vegetation.

Soil-vegetation relationships on a banded ironstone 'island', Carajás Plateau, Brazilian Eastern Amazonia.

PubMed

Nunes, Jaquelina A; Schaefer, Carlos E G R; Ferreira Júnior, Walnir G; Neri, Andreza V; Correa, Guilherme R; Enright, Neal J

2015-01-01

Vegetation and soil properties of an iron-rich canga (laterite) island on the largest outcrop of banded-iron formation in Serra de Carajás (eastern Amazonia, Brazil) were studied along a topographic gradient (738-762 m asl), and analyzed to test the hypothesis that soil chemical and physical attributes play a key role in the structure and floristic composition of these plant communities. Soil and vegetation were sampled in eight replicate plots within each of the four vegetation types. Surface (0-10 cm) soil samples from each plot were analyzed for basic cations, N, P and plant species density for all species was recorded. CCA ordination analysis showed a strong separation between forest and non-forest sites on the first axis, and between herbaceous and shrubby campo rupestre on the second axis. The four vegetation types shared few plant species, which was attributed to their distinctive soil environments and filtering of their constituent species by chemical, physical and hydrological constraints. Thus, we can infer that Edaphic (pedological) factors are crucial in explaining the types and distributions of campo rupestre vegetation associated with ferruginous ironstone uplands (Canga) in Carajás, eastern Amazonia, therefore the soil properties are the main drivers of vegetation composition and structure on these ironstone islands.

Impact of Prairie Cover on Hydraulic Conductivity and Storm Water Runoff

NASA Astrophysics Data System (ADS)

Herkes, D. M. G.; Gori, A.; Juan, A.

2017-12-01

Houston has long struggled to find effective solutions to its historic flooding problems. Conventional strategies have revolved around constructing hard infrastructure such as levees or regional detention ponds to reduce flood impacts. However, there has been a recent shift to explore the implementation of nature-based solutions in reducing flood impacts. This is due to the price of structural mechanisms, as well as their failure to adequately protect areas from flooding during the latest flood events. One alternative could be utilizing the natural water retention abilities of native Texas prairies. This study examines the effect of Texas prairie areas in increasing soil infiltration capacities, thereby increasing floodwater storage and reducing surface runoff. For this purpose, an infiltration study of 15 sites was conducted on lands owned by the Katy Prairie Conservancy within Cypress Creek watershed. Located in Northwest Houston, it is an area which had been heavily impacted by recent flood events. Each sampling site was selected to represent a particular land cover or vegetation type, ranging from developed open space to native prairies. Field test results are then compared to literature values of soil infiltration capacity in order to determine the infiltration benefit of each vegetation type. Test results show that certain vegetation, especially prairies, significantly increase the infiltration capacity of the underlying soil. For example, the hydraulic conductivity of prairie on sandy loam soil is approximately an order of magnitude higher than that of the soil itself. Finally, a physics-based hydrologic model is utilized to evaluate the flood reduction potential of native Texas prairie. This model represents Cypress Creek watershed in gridded cell format, and allows varying hydraulic and infiltration parameters at each cell. Design storms are run to obtain flow hydrographs for selected watch points in the study area. Two scenarios are simulated and compared: 1) infiltration capacity from soil only and 2) the augmented infiltration capacity of soil due to vegetation. Modeled results show a notable decrease in both total runoff volume and peak flows under the augmented infiltration scenario. This decrease demonstrates the benefit of native Texas prairie land in reducing flood risks.

Neogene vegetation development in the Amazon Basin: evidence from marine well-2, Foz do Amazonas (Brazil)

NASA Astrophysics Data System (ADS)

Bogota-Angel, Raul; Chemale Junior, Farid; Davila, Roberto; Soares, Emilson; Pinto, Ricardo; Do Carmo, Dermeval; Hoorn, Carina

2014-05-01

Origen and development of the highly diverse Amazon tropical forest has mostly been inferred from continental sites. However, sediment records in the marine Foz do Amazonas Basin can provide important information to better understand the influence of the Andes uplift and climate change on its plant biomes evolution since the Neogene. Sediment analyses of samples from BP-Petrobras well 1 and 2, drilled in the Amazon Fan, allowed to infer the onset of the transcontinental Amazon river and the fan phase during the middle to late Miocene (c. 10.5 Ma). As part of the CLIMAMAZON research programme we performed pollen analysis on the 10.5 to 0.4 Ma time interval. 76 ditch cutting samples of the upper 4165 m sediments of well 2 permitted us to infer changes in floral composition in the Amazon Basin. The palynological spectra across this interval (nannofossil based age model) include pollen, fern spores, dinocysts and foram lignings. When possible pollen and fern spores were grouped in four vegetation types: estuarine, tropical, mountain forest and high mountain open treeless vegetation. Pollen is generally corroded and reflects the effects of sediment transportation while reworked material is also common. Good pollen producers such as Poaceae, Asteraceae and Cyperaceae are common and reflect indistinctive vegetation types particularly those associated to riverine systems. Rhizophora/Zonocostites spp. indicate "close-distance" mangrove development. Tropical forest biomes are represented by pollen that resemble Moraceae-Urticaceae, Melastomataceae-Combretaceae, Sapotaceae, Alchornea, Euphorbiaceae, Rubiaceae, Bignoniaceae, Mauritia and Arecaceae. Myrica, and particularly sporadic occurrences of fossil fern spores like Lophosoria, and Cyathea suggest the development of a moist Andean forest in areas above 1000 m. First indicators of high altitudes appear in the last part of late Miocene with taxa associated to current Valeriana and particularly Polylepis, a neotropical taxon currently growing along the Andean fluvial system on altitudes between c. 2000 up to c. 4800 m. Alnus is an important Andean forest taxa since Pliocene. In summary, the Neogene palynological record of the Amazon Fan strongly reflects and confirms the influence of the uplift of the Andes and its transcontinental character from late Miocene onwards.

Remote sensing captures varying temporal patterns of vegetation between human-altered and natural landscapes.

PubMed

Leong, Misha; Roderick, George K

2015-01-01

Global change has led to shifts in phenology, potentially disrupting species interactions such as plant-pollinator relationships. Advances in remote sensing techniques allow one to detect vegetation phenological diversity between different land use types, but it is not clear how this translates to other communities in the ecosystem. Here, we investigated the phenological diversity of the vegetation across a human-altered landscape including urban, agricultural, and natural land use types. We found that the patterns of change in the vegetation indices (EVI and NDVI) of human-altered landscapes are out of synchronization with the phenology in neighboring natural California grassland habitat. Comparing these findings to a spatio-temporal pollinator distribution dataset, EVI and NDVI were significant predictors of total bee abundance, a relationship that improved with time lags. This evidence supports the importance of differences in temporal dynamics between land use types. These findings also highlight the potential to utilize remote sensing data to make predictions for components of biodiversity that have tight vegetation associations, such as pollinators.

Analysis of Manning’s and Drag Coefficients for Flexible Submerged Vegetation

NASA Astrophysics Data System (ADS)

Yusof, Khamaruzaman Wan; Mujahid Muhammad, Muhammad; Mustafa, Muhammad Raza Ul; Azazi Zakaria, Nor; Gahani, Aminuddin Ab.

2017-06-01

Accurate determination of flow resistance is of great significance in modelling of open channels that will convey water efficiently. Although, resistance or drag induced by vegetation have been systematically studied for several decades, estimating of the resistance remain as a challenge. This is because most of previous studies use artificial vegetation to investigate flow - vegetation interactions. To overcome this, the present study evaluates the vegetation resistance in terms of Manning’s roughness coefficient and drag coefficient using a natural flexible vegetation (cow grass) under submerged condition. From the experimental result obtained, it was observed that the Manning’s and drag coefficients decreased with the increasing in average velocity. Also, graphical relationship between Manning’s coefficient, n and drag coefficient, CD has been developed with R2 = 0.9465, which indicate that there exist a strong correlation between n and CD, and one can use the proposed graphical model to predict the n - values corresponding to the CD - values.

Postcaesarean open-heart surgery for Streptococcus sanguinis infective endocarditis

PubMed Central

Kongwattanakul, Kiattisak; Tribuddharat, Sirirat; Prathanee, Sompop; Pachirat, Orathai

2013-01-01

A 33-week pregnant (gravida 3), 29-year-old woman was transferred for management of Streptococcus sanguinis infective endocarditis. A vegetation was present on the posterior leaflet of the mitral valve with moderate mitral regurgitation. On admission (day 1), the ultrasound examination revealed splenic abscesses and retarded intrauterine growth albeit with normal vessels. The fetal heart rate was 140 bpm. On day 11, the baby was delivered by Caesarean, and then the mother underwent tubal ligation followed by a mitral valve repair. The splenic abscess was treated with antibiotics. The woman was clinically stable and recovered uneventfully. This successful outcome was achieved by a strategic (optimal and sequential) timeline for selecting the mode of delivery and type of mitral valve correction. PMID:24234426

Vegetation-Associated Impacts on Arctic Tundra Bacterial and Microeukaryotic Communities

PubMed Central

Shi, Yu; Xiang, Xingjia; Shen, Congcong; Neufeld, Josh D.; Walker, Virginia K.

2014-01-01

The Arctic is experiencing rapid vegetation changes, such as shrub and tree line expansion, due to climate warming, as well as increased wetland variability due to hydrological changes associated with permafrost thawing. These changes are of global concern because changes in vegetation may increase tundra soil biogeochemical processes that would significantly enhance atmospheric CO2 concentrations. Predicting the latter will at least partly depend on knowing the structure, functional activities, and distributions of soil microbes among the vegetation types across Arctic landscapes. Here we investigated the bacterial and microeukaryotic community structures in soils from the four principal low Arctic tundra vegetation types: wet sedge, birch hummock, tall birch, and dry heath. Sequencing of rRNA gene fragments indicated that the wet sedge and tall birch communities differed significantly from each other and from those associated with the other two dominant vegetation types. Distinct microbial communities were associated with soil pH, ammonium concentration, carbon/nitrogen (C/N) ratio, and moisture content. In soils with similar moisture contents and pHs (excluding wet sedge), bacterial, fungal, and total eukaryotic communities were correlated with the ammonium concentration, dissolved organic nitrogen (DON) content, and C/N ratio. Operational taxonomic unit (OTU) richness, Faith's phylogenetic diversity, and the Shannon species-level index (H′) were generally lower in the tall birch soil than in soil from the other vegetation types, with pH being strongly correlated with bacterial richness and Faith's phylogenetic diversity. Together, these results suggest that Arctic soil feedback responses to climate change will be vegetation specific not just because of distinctive substrates and environmental characteristics but also, potentially, because of inherent differences in microbial community structure. PMID:25362064

Vegetation-associated impacts on arctic tundra bacterial and microeukaryotic communities.

PubMed

Shi, Yu; Xiang, Xingjia; Shen, Congcong; Chu, Haiyan; Neufeld, Josh D; Walker, Virginia K; Grogan, Paul

2015-01-01

The Arctic is experiencing rapid vegetation changes, such as shrub and tree line expansion, due to climate warming, as well as increased wetland variability due to hydrological changes associated with permafrost thawing. These changes are of global concern because changes in vegetation may increase tundra soil biogeochemical processes that would significantly enhance atmospheric CO2 concentrations. Predicting the latter will at least partly depend on knowing the structure, functional activities, and distributions of soil microbes among the vegetation types across Arctic landscapes. Here we investigated the bacterial and microeukaryotic community structures in soils from the four principal low Arctic tundra vegetation types: wet sedge, birch hummock, tall birch, and dry heath. Sequencing of rRNA gene fragments indicated that the wet sedge and tall birch communities differed significantly from each other and from those associated with the other two dominant vegetation types. Distinct microbial communities were associated with soil pH, ammonium concentration, carbon/nitrogen (C/N) ratio, and moisture content. In soils with similar moisture contents and pHs (excluding wet sedge), bacterial, fungal, and total eukaryotic communities were correlated with the ammonium concentration, dissolved organic nitrogen (DON) content, and C/N ratio. Operational taxonomic unit (OTU) richness, Faith's phylogenetic diversity, and the Shannon species-level index (H') were generally lower in the tall birch soil than in soil from the other vegetation types, with pH being strongly correlated with bacterial richness and Faith's phylogenetic diversity. Together, these results suggest that Arctic soil feedback responses to climate change will be vegetation specific not just because of distinctive substrates and environmental characteristics but also, potentially, because of inherent differences in microbial community structure. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Analysis of Differences in Phenology Extracted from the Enhanced Vegetation Index and the Leaf Area Index

PubMed Central

Wang, Cong; Li, Jing; Wu, Shanlong; Xia, Chuanfu

2017-01-01

Remote-sensing phenology detection can compensate for deficiencies in field observations and has the advantage of capturing the continuous expression of phenology on a large scale. However, there is some variability in the results of remote-sensing phenology detection derived from different vegetation parameters in satellite time-series data. Since the enhanced vegetation index (EVI) and the leaf area index (LAI) are the most widely used vegetation parameters for remote-sensing phenology extraction, this paper aims to assess the differences in phenological information extracted from EVI and LAI time series and to explore whether either index performs well for all vegetation types on a large scale. To this end, a GLASS (Global Land Surface Satellite Product)-LAI-based phenology product (GLP) was generated using the same algorithm as the MODIS (Moderate Resolution Imaging Spectroradiometer)-EVI phenology product (MLCD) over China from 2001 to 2012. The two phenology products were compared in China for different vegetation types and evaluated using ground observations. The results show that the ratio of missing data is 8.3% for the GLP, which is less than the 22.8% for the MLCD. The differences between the GLP and the MLCD become stronger as the latitude decreases, which also vary among different vegetation types. The start of the growing season (SOS) of the GLP is earlier than that of the MLCD in most vegetation types, and the end of the growing season (EOS) of the GLP is generally later than that of the MLCD. Based on ground observations, it can be suggested that the GLP performs better than the MLCD in evergreen needleleaved forests and croplands, while the MLCD performs better than the GLP in shrublands and grasslands. PMID:28867773

Quantifying Ground-Water and Surface-Water Discharge from Evapotranspiration Processes in 12 Hydrographic Areas of the Colorado Regional Ground-Water Flow System, Nevada, Utah, and Arizona

USGS Publications Warehouse

DeMeo, Guy A.; Smith, J. LaRue; Damar, Nancy A.; Darnell, Jon

2008-01-01

Rapid population growth in southern Nevada has increased the demand for additional water supplies from rural areas of northern Clark and southern Lincoln counties to meet projected water-supply needs. Springs and rivers in these undeveloped areas sustain fragile riparian habitat and may be susceptible to ground-water withdrawals. Most natural ground-water and surface-water discharge from these basins occurs by evapotranspiration (ET) along narrow riparian corridors that encompassed about 45,000 acres or about 1 percent of the study area. This report presents estimates of ground- and surface-water discharge from ET across 3.5 million acres in 12 hydrographic areas of the Colorado Regional Ground-Water Flow System. Ground-and surface-water discharge from ET were determined by identifying areas of ground- and surface-water ET, delineating areas of similar vegetation and soil conditions (ET units), and computing ET rates for each of these ET units. Eight ET units were identified using spectral-reflectance characteristics determined from 2003 satellite imagery, high-resolution aerial photography, and land classification cover. These ET units are dense meadowland vegetation (200 acres), dense woodland vegetation (7,200 acres), moderate woodland vegetation (6,100 acres), dense shrubland vegetation (5,800 acres), moderate shrubland vegetation (22,600 acres), agricultural fields (3,100 acres), non-phreatophytic areas (3,400,000 acres), and open water (300 acres). ET from diffuse ground-water and channelized surface-water is expressed as ETgs and is equal to the difference between total annual ET and precipitation. Total annual ET rates were calculated by the Bowen ratio and eddy covariance methods using micrometeorological data collected from four sites and estimated at 3.9 ft at a dense woodland site (February 2003 to March 2005), 3.6 ft at a moderate woodland site (July 2003 to October 2006), 2.8 ft at a dense shrubland site (June 2005 to October 2006), and 1.5 ft at a moderate shrubland site (April 2006 to October 2006). Annual ETgs rates were 3.4 ft for dense woodland vegetation, 3.2 ft for moderate woodland vegetation, 2.2 ft for dense shrubland vegetation, and 1.0 ft for moderate shrubland vegetation. Published annual rates of ETgs were used for the other ET units found in the study area. These rates were 3.4 ft for dense meadowland vegetation, 5.2 ft for agricultural fields, and 4.9 ft for open water. For the non-phreatophytic ET unit, ETgs was assumed to be zero. Estimated ground- and surface-water discharge from ET was calculated by multiplying the ETgs by the ET-unit acreage and equaled 24,480 acre-ft for dense woodland vegetation, 19,520 acre-ft for moderate woodland vegetation, 12,760 acre-ft for dense shrubland vegetation, 22,600 acre-ft for moderate shrubland vegetation, 680 acre-ft for dense meadowland vegetation, 16,120 acre-ft for agricultural fields, 1,440 acre-ft for open water, and 0 acre-ft for the non-phreatophytic ET unit. Estimated ground-water and surface-water discharge from ET from each hydrographic area was calculated by summing the total annual ETgs rate for ET units found within each hydrographic area and equaled 1,952 acre-ft for the Black Mountains Area, 6,080 acre-ft for California Wash, 4,090 acre-ft for the Muddy River Springs Area, 11,510 acre-ft for Lower Moapa Valley, 51,960 acre-ft for the Virgin River Valley, 16,168 acre-ft for Lower Meadow Valley Wash, 5,840 acre-ft for Clover Valley, and 0 acre-ft for Coyote Spring Valley, Kane Springs Valley, Tule Desert, Hidden Valley (North), and Garnet Valley. The annual discharge from ETgs for the study area totals about 98,000 acre-ft.

Forest vegetation of the Black Hills National Forest of South Dakota and Wyoming: A habitat type classification

Treesearch

George R. Hoffman; Robert R. Alexander

1987-01-01

A vegetation classification based on concepts and methods developed by Daubenmire was used to identify 12 forest habitat types and one shrub habitat type in the Black Hills. Included were two habitat types in the Quercus macrocarpa series, seven in the Pinus ponderosa series, one in the Populus tremuloides series, two in the Picea glaucci series, and one in the...

Vegetable variety: an effective strategy to increase vegetable intake in adults.

PubMed

Meengs, Jennifer S; Roe, Liane S; Rolls, Barbara J

2012-08-01

Effective strategies are needed to increase vegetable intake in accordance with health recommendations. Previous research has shown that increasing the variety of foods leads to increased consumption, yet this strategy has not been investigated for promoting vegetable intake. This crossover study, conducted in 2008 and 2009, tested whether filling half the plate with a variety of vegetables influences vegetable consumption and meal energy intake. Once a week for 4 weeks, a meal of pasta and cooked vegetables was consumed ad libitum by 66 adults (34 women, 32 men). The meals were varied in the type of vegetables offered: at three meals 600 g of a single vegetable was served (broccoli, carrots, or snap peas) and at one meal 200 g of each of the three vegetables was served side by side. Data were analyzed using a mixed linear model with repeated measures. In this study, serving a variety of vegetables increased vegetable intake at the meal (P<0.0001). Subjects ate more vegetables when served the variety than when served any single type; the mean increase was 48±6 g, or more than one-half serving. This increase remained significant when intake of the variety of vegetables was compared with the preferred vegetable of each participant (mean 25±8 g; P=0.002). Vegetable intake was not significantly related to energy intake at the meal. The results of this study demonstrate that increasing the variety of low-energy-dense vegetables served at a meal can be used as a strategy to increase vegetable intake. Copyright © 2012 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Study of Wetland Ecosystem Vegetation Using Satellite Data

NASA Astrophysics Data System (ADS)

Dyukarev, E. A.; Alekseeva, M. N.; Golovatskaya, E. A.

2017-12-01

The normalized difference vegetation index (NDVI) is used to estimate the aboveground net production (ANP) of wetland ecosystems for the key area at the South Taiga zone of West Siberia. The vegetation index and aboveground production are related by linear dependence and are specific for each wetland ecosystem. The NDVI grows with an increase in the ANP at wooded oligotrophic ecosystems. Open oligotrophic bogs and eutrophic wetlands are characterized by an opposite relation. Maps of aboveground production for wetland ecosystems are constructed for each study year and for the whole period of studies. The average aboveground production for all wetland ecosystems of the key area, which was estimated with consideration for the area they occupy and using the data of satellite measurements of the vegetation index, is 305 g C/m2/yr. The total annual carbon accumulation in aboveground wetland vegetation in the key area is 794600 t.

Study on leaching of pollutants from vegetable tanning residue.

PubMed

Mazumder, Debabrata; Biswas, Santosh; Bandyopadhyay, Pratip

2006-07-01

The processing of heavy leather employs the vegetable tanning method involving use of tan liquor. The solid residue of this vegetable tanning process aggravates the water pollution by means of leaching of tannin and other associatedpollutants. Tannin is a biologically resistant compound causing several problems in animal body. The present study dealt with the pollution hazard arising out of leaching of pollutants from the open dumped vegetable tanning residue by rainfall washing. The concerned pollutants were pH, Chemical Oxygen Demand (COD), tannin,sulfate and chloride concentration. To explore the possible extent of contamination of these pollutants in the leached water, two different masses (2 kg and 3 kg) of tanning residue were employed. The results of the study showed that there was a continuous release of pollutants from the vegetable tanning residue. Moreover, there was no regular variation in various pollutant concentrations in both the cases solely due to non-homogeneity of the residue.

Sediment phosphate composition in relation to emergent macrophytes in the Doñana Marshes (SW Spain)

USGS Publications Warehouse

Reina, M.; Espinar, J.L.; Serrano, L.

2006-01-01

We have studied the effect of the presence of emergent macrophytes on the sediment phosphate composition of a eutrophic shallow marsh on the NE margin of Doñana (SW Spain). Top sediment and water samples were collected from both the open-water and the vegetated sites at three areas covered by different plant species: Scirpus maritimus, Juncus subulatus and Phragmites australis. The concentration of organic matter was significantly higher in the top sediment of sites covered by vegetation than in their adjacent open-water sites at the three vegetation areas. The P-fractional composition showed that the sediment was dominated by the inorganic P-fractions in all cases, reaching the highest concentration in the Ca-bound P-fraction (281–372 μg g−1 d.w.). The sum of all P-fractions was significantly higher in the top sediment of the sites covered by J. subulatus and S. maritimus than in their adjacent open-water sites, and so were the org-P fraction extracted by hot NaOH and the concentration of phytate within this fraction. Deposition of plant material on the top sediment of areas vegetated by J. subulatus and S. maritimus explains these differences. The P-fractional composition of the seeds from J. subulatus showed that they contained a large proportion of organic P-fractions, particularly of the fraction extracted by hot NaOH (1868 μg g−1 d.w., 85% of which was phytate). The presence of emergent macrophytes, therefore, influenced the distribution of P-fractions in the sediment depending on plant species. The P-bioavailability of shallow aquatic systems must be fully understood if wetlands are to be protected from further eutrophication.

Microbiological quality of open ready-to-eat salad vegetables: effectiveness of food hygiene training of management.

PubMed

Sagoo, S K; Little, C L; Mitchell, R T

2003-09-01

During September and October 2001, a microbiological study of open, ready-to-eat, prepared salad vegetables from catering or retail premises was undertaken to determine their microbiological quality. The study focused on those salad vegetables that were unwrapped and handled either by staff or customers in the premises where the sample was taken. Examination of salad vegetables from food service areas and customer self-service bars revealed that most (97%; 2,862 of 2,950) were of satisfactory or acceptable microbiological quality, 3% (87) were of unsatisfactory microbiological quality because of Escherichia coli levels in the range of 10(2) to 10(5) colony-forming units per gram. One (<1%) sample was of unacceptable microbiological quality because of the presence of Listeria monocytogenes at 840 colony-forming units per gram. The pathogens E. coli O157, Campylobacter spp., and salmonellas were not detected in any of the samples examined. The display area for most food service and preparation areas (95%) and self-service salad bars (98%) that were visited was judged to be visibly clean by the sampling officer. Most self-service bars (87%) were regularly supervised or inspected by staff during opening hours, and designated serving utensils were used in most salad bars (92%) but in only a minority of food service areas (35%). A hazard analysis system was in place in most (80%) premises, and in 61%, it was documented. Most (90%) managers had received food hygiene training. A direct relationship was shown between increased confidence in the food business management and the presence of food safety procedures and the training of management in food hygiene.

Characterization and gene cloning of the rice (Oryza sativa L.) dwarf and narrow-leaf mutant dnl3.

PubMed

Shi, L; Wei, X J; Adedze, Y M N; Sheng, Z H; Tang, S Q; Hu, P S; Wang, J L

2016-09-16

The dwarf and narrow-leaf rice (Oryza sativa L.) mutant dnl3 was isolated from the Japonica cultivar Zhonghua 11 (wild-type). dnl3 exhibited pleiotropic developmental defects. The narrow-leaf phenotype resulted from a marked reduction in the number of vascular bundles, while the dwarf stature was caused by the formation of foreshortened internodes and a reduced number of parenchyma cells. The suggestion that cell division is impaired in the mutant was consistent with the transcriptional behavior of various genes associated with cell division. The mutant was less responsive to exogenously supplied gibberellic acid than the wild-type, and profiling the transcription of genes involved in gibberellin synthesis and response revealed that a lesion in the mutant affected gibberellin signal transduction. The dnl3 phenotype was inherited as a single-dominant gene, mapping within a 19.1-kb region of chromosome 12, which was found to harbor three open reading frames. Resequencing the open reading frames revealed that the mutant carried an allele at one of the three genes that differed from the wild-type sequence by 2-bp deletions; this gene encoded a cellulose synthase-like D4 (CSLD4) protein. Therefore, OsCSLD4 is a candidate gene for DNL3. DNL3 was expressed in all of the rice organs tested at the heading stage, particularly in the leaves, roots, and culms. These results suggest that DNL3 plays important roles in rice leaf morphogenesis and vegetative development.

Fuel dynamics and fire behaviour in Australian mallee and heath vegetation

Treesearch

Juanita Myers; Jim Gould; Miguel Cruz; Meredith Henderson

2007-01-01

In southern Australia, shrubby heath vegetation together with woodlands dominated by multistemmed eucalypts (mallee) comprise areas of native vegetation with important biodiversity values. These vegetation types occur in semiarid and mediterranean climates and can experience large frequent fires. This study is investigating changes in the fuel complex with time, fuel...

Factors affecting hatch success of hawksbill sea turtles on Long Island, Antigua, West Indies.

PubMed

Ditmer, Mark Allan; Stapleton, Seth Patrick

2012-01-01

Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata) hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP) to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2%) during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific vegetation types on hatch success and hatchling sex ratios is needed. Future research should explore the roles of sand structure, nest moisture, and local weather conditions.

Factors Affecting Hatch Success of Hawksbill Sea Turtles on Long Island, Antigua, West Indies

PubMed Central

Ditmer, Mark Allan; Stapleton, Seth Patrick

2012-01-01

Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata) hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP) to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2%) during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific vegetation types on hatch success and hatchling sex ratios is needed. Future research should explore the roles of sand structure, nest moisture, and local weather conditions. PMID:22802928

Vegetation recovery in an oil-impacted and burned Phragmites australis tidal freshwater marsh.

PubMed

Zengel, Scott; Weaver, Jennifer; Wilder, Susan L; Dauzat, Jeff; Sanfilippo, Chris; Miles, Martin S; Jellison, Kyle; Doelling, Paige; Davis, Adam; Fortier, Barret K; Harris, James; Panaccione, James; Wall, Steven; Nixon, Zachary

2018-01-15

In-situ burning of oiled marshes is a cleanup method that can be more effective and less damaging than intrusive manual and mechanical methods. In-situ burning of oil spills has been examined for several coastal marsh types; however, few published data are available for Phragmites australis marshes. Following an estimated 4200gallon crude oil spill and in-situ burn in a Phragmites tidal freshwater marsh at Delta National Wildlife Refuge (Mississippi River Delta, Louisiana), we examined vegetation impacts and recovery across 3years. Oil concentrations in marsh soils were initially elevated in the oiled-and-burned sites, but were below background levels within three months. Oiling and burning drastically affected the marsh vegetation; the formerly dominant Phragmites, a non-native variety in our study sites, had not fully recovered by the end of our study. However, overall vegetation recovery was rapid and local habitat quality in terms of native plants, particularly Sagittaria species, and wildlife value was enhanced by burning. In-situ burning appears to be a viable response option to consider for future spills in marshes with similar plant species composition, hydrogeomorphic settings, and oiling conditions. In addition, likely Phragmites stress from high water levels and/or non-native scale insect damage was also observed during our study and has recently been reported as causing widespread declines or loss of Phragmites stands in the Delta region. It remains an open question if these stressors could lead to a shift to more native vegetation, similar to what we observed following the oil spill and burn. Increased dominance by native plants may be desirable as local patches, but widespread loss of Phragmites, even if replaced by native species, could further acerbate coastal erosion and wetland loss, a major concern in the region. Copyright © 2017 Elsevier B.V. All rights reserved.

Evolution of Subaerial Coastal Fluvial Delta Island Topography into Multiple Stable States Under Influence of Vegetation and Stochastic Hydrology

NASA Astrophysics Data System (ADS)

Moffett, K. B.; Smith, B. C.; O'Connor, M.; Mohrig, D. C.

2014-12-01

Coastal fluvial delta morphodynamics are prominently controlled by external fluvial sediment and water supplies; however, internal sediment-water-vegetation feedbacks are now being proposed as potentially equally significant in organizing and maintaining the progradation and aggradation of such systems. The time scales of fluvial and climate influences on these feedbacks, and of their responses, are also open questions. Historical remote sensing study of the Wax Lake Delta model system (Louisiana, USA) revealed trends in the evolution of the subaerial island surfaces from a non-systematic arrangement of elevations to a discrete set of levees and intra-island platforms with distinct vegetation types, designated as high marsh, low marsh, and mudflat habitat. We propose that this elevation zonation is consistent with multiple stable state theory, e.g. as applied to tidal salt marsh systems but not previously to deltas. According to zonally-distributed sediment core analyses, differentiation of island elevations was not due to organic matter accumulation as in salt marshes, but rather by differential mineral sediment accumulation with some organic contributions. Mineral sediment accumulation rates suggested that elevation growth was accelerating or holding steady over time, at least to date in this young delta, in contrast to theory suggesting rates should slow as elevation increases above mean water level. Hydrological analysis of island flooding suggested a prominent role of stochastic local storm events in raising island water levels and supplying mineral sediment to the subaerial island surfaces at short time scales; over longer time scales, the relative influences of local storms and inland/regional floods on the coupled sediment-water-vegetation system of the subaerial delta island surfaces remain the subject of ongoing study. These results help provide an empirical foundation for the next generation of coupled sediment-water-vegetation modeling and theory.

SPRUCE Vegetation Phenology in Experimental Plots from Phenocam Imagery, 2015-2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richardson, Andrew D.; Hufkens, Koen; Milliman, Thomas

This data set consists of PhenoCam data from the SPRUCE experiment from the beginning of whole ecosystem warming in August 2015 through the end of 2017. Digital cameras, or phenocams, installed in each SPRUCE enclosure track seasonal variation in vegetation “greenness”, a proxy for vegetation phenology and associated physiological activity. Regions of interest (ROIs) were defined for vegetation types (1) Picea trees (EN, evergreen needleleaf); (2) Larix trees (DN, deciduous needleleaf); and (3) the mixed shrub layer (SH, shrubs). This data set consists of two sets of data files: (1) standard “3-day summary product files” for each camera and eachmore » ROI (i.e. vegetation type), characterizing vegetation color at a 3-day time step and (2) a “transition date file” containing the estimated “greenness rising” (spring) and “greenness falling” (autumn) transition dates.« less

Exposure of tropical ecosystems to artificial light at night: Brazil as a case study.

PubMed

Freitas, Juliana Ribeirão de; Bennie, Jon; Mantovani, Waldir; Gaston, Kevin J

2017-01-01

Artificial nighttime lighting from streetlights and other sources has a broad range of biological effects. Understanding the spatial and temporal levels and patterns of this lighting is a key step in determining the severity of adverse effects on different ecosystems, vegetation, and habitat types. Few such analyses have been conducted, particularly for regions with high biodiversity, including the tropics. We used an intercalibrated version of the Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) images of stable nighttime lights to determine what proportion of original and current Brazilian vegetation types are experiencing measurable levels of artificial light and how this has changed in recent years. The percentage area affected by both detectable light and increases in brightness ranged between 0 and 35% for native vegetation types, and between 0 and 25% for current vegetation (i.e. including agriculture). The most heavily affected areas encompassed terrestrial coastal vegetation types (restingas and mangroves), Semideciduous Seasonal Forest, and Mixed Ombrophilous Forest. The existing small remnants of Lowland Deciduous and Semideciduous Seasonal Forests and of Campinarana had the lowest exposure levels to artificial light. Light pollution has not often been investigated in developing countries but our data show that it is an environmental concern.

Evaluating CMIP5 Simulations of Historical Continental Climate with Koeppen Bioclimatic Metrics

NASA Astrophysics Data System (ADS)

Phillips, T. J.; Bonfils, C.

2013-12-01

The classic Koeppen bioclimatic classification scheme associates generic vegetation types (e.g. grassland, tundra, broadleaf or evergreen forests, etc.) with regional climate zones defined by their annual cycles of continental temperature (T) and precipitation (P), considered together. The locations or areas of Koeppen vegetation types derived from observational data thus can provide concise metrical standards for simultaneously evaluating climate simulations of T and P in naturally defined regions. The CMIP5 models' collective ability to correctly represent two variables that are critically important for living organisms at regional scales is therefore central to this evaluation. For this study, 14 Koeppen vegetation types are derived from annual-cycle climatologies of T and P in some 3 dozen CMIP5 simulations of the 1980-1999 period. Metrics for evaluating the ability of the CMIP5 models to simulate the correct locations and areas of each vegetation type, as well as measures of overall model performance, also are developed. It is found that the CMIP5 models are generally most deficient in simulating: 1) climates of drier Koeppen zones (e.g. desert, savanna, grassland, steppe vegetation types) located in the southwestern U.S. and Mexico, eastern Europe, southern Africa, and central Australia; 2) climates of regions such as central Asia and western South America where topography plays a key role. Details of regional T or P biases in selected simulations that exemplify general model performance problems also will be presented. Acknowledgments: This work was funded by the U.S. Department of Energy Office of Science and was performed at the Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Map of Koeppen vegetation types derived from observed T and P.

Runoff and erosion in a pinon-juniper woodland: Influence of vegetation patches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reid, K.D.; Wilcox, B.P.; Breshears, D.D.

1999-12-01

In many semiarid regions, runoff and erosion differ according to vegetation patch type. These differences, although hypothesized to fundamentally affect ecological processes, have been poorly quantified. In a semiarid pinion-juniper woodland [Pinus edulis Engelm. and Juniperus monosperma (Engelm) Sarg.] in northern New Mexico, the authors measured runoff and erosion from the three patch types that compose these woodlands: Canopy patches (those beneath woody plants), vegetated patched in intercanopy areas, and bare patches in intercanopy areas. The bare intercanopy patches exhibited the highest rates, followed by vegetated intercanopy patches and then by canopy patches. Large convective summer storms, though relatively infrequent,more » generated much of the runoff and most of the sediment; prolonged frontal storms were capable of generating considerable runoff but little sediment. A portion of the runoff and most of the sediment generated from bare intercanopy patches was redistributed down-slope, probably to adjacent vegetated intercanopy patches, demonstrating connectivity between these two patch types. Their results indicate that there are significant and important differences in runoff and sediment production from the three patch types; that bare intercanopy patches act as sources of both water and sediment for the vegetated intercanopy patches; and that the transfer of water and sediment at small scales is both frequent enough and substantial enough to be considered ecologically significant.« less

Arctic Tundra Vegetation Functional Types Based on Photosynthetic Physiology and Optical Properties

NASA Technical Reports Server (NTRS)

Huemmrich, Karl F.; Gamon, John; Tweedie, Craig; Campbell, Petya K.; Landis, David R.; Middleton, Elizabeth M.

2013-01-01

Non-vascular plants (lichens and mosses) are significant components of tundra landscapes and may respond to climate change differently from vascular plants affecting ecosystem carbon balance. Remote sensing provides critical tools for monitoring plant cover types, as optical signals provide a way to scale from plot measurements to regional estimates of biophysical properties, for which spatial-temporal patterns may be analyzed. Gas exchange measurements were collected for pure patches of key vegetation functional types (lichens, mosses, and vascular plants) in sedge tundra at Barrow AK. These functional types were found to have three significantly different values of light use efficiency (LUE) with values of 0.013+/-0.001, 0.0018+/-0.0002, and 0.0012+/-0.0001 mol C/mol absorbed quanta for vascular plants, mosses and lichens, respectively. Discriminant analysis of the spectra reflectance of these patches identified five spectral bands that separated each of these vegetation functional types as well as nongreen material (bare soil, standing water, and dead leaves). These results were tested along a 100 m transect where midsummer spectral reflectance and vegetation coverage were measured at one meter intervals.

Special-Status Plant Species Surveys and Vegetation Mapping at Lawrence Livermore National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preston, R E

This report presents the results of Jones & Stokes special-status plant surveys and vegetation mapping for the University of California, Lawrence Livermore National Laboratory (LLNL). Special-status plant surveys were conducted at Site 300 in April to May 1997 and in March to April 2002. Eight special-status plants were identified at Site 300: large-flowered fiddleneck, big tarplant, diamond-petaled poppy, round-leaved filaree, gypsum-loving larkspur, California androsace, stinkbells, and hogwallow starfish. Maps identifying the locations of these species, a discussion of the occurrence of these species at Site 300, and a checklist of the flora of Site 300 are presented. A reconnaissance surveymore » of the LLNL Livermore Site was conducted in June 2002. This survey concluded that no special-status plants occur at the Livermore Site. Vegetation mapping was conducted in 2001 at Site 300 to update a previous vegetation study done in 1986. The purpose of the vegetation mapping was to update and to delineate more precisely the boundaries between vegetation types and to map vegetation types that previously were not mapped. The vegetation map is presented with a discussion of the vegetation classification used.« less

Do Humans Really Prefer Semi-open Natural Landscapes? A Cross-Cultural Reappraisal

PubMed Central

Hägerhäll, Caroline M.; Ode Sang, Åsa; Englund, Jan-Eric; Ahlner, Felix; Rybka, Konrad; Huber, Juliette; Burenhult, Niclas

2018-01-01

There is an assumption in current landscape preference theory of universal consensus in human preferences for moderate to high openness in a natural landscape. This premise is largely based on empirical studies of urban Western populations. Here we examine for the first time landscape preference across a number of geographically, ecologically and culturally diverse indigenous populations. Included in the study were two urban Western samples of university students (from southern Sweden) and five non-Western, indigenous and primarily rural communities: Jahai (Malay Peninsula), Lokono (Suriname), Makalero (Timor), Makasae (Timor), and Wayuu (Colombia). Preference judgements were obtained using pairwise forced choice assessments of digital visualizations of a natural landscape varied systematically on three different levels of topography and vegetation density. The results show differences between the Western and non-Western samples, with interaction effects between topography and vegetation being present for the two Swedish student samples but not for the other five samples. The theoretical claim of human preferences for half-open landscapes was only significantly confirmed for the student sample comprising landscape architects. The five non Western indigenous groups all preferred the highest level of vegetation density. Results show there are internal similarities between the two Western samples on the one hand, and between the five non-Western samples on the other. To some extent this supports the idea of consensus in preference, not universally but within those categories respectively. PMID:29896141

Trees in urban parks and forests reduce O3, but not NO2 concentrations in Baltimore, MD, USA

NASA Astrophysics Data System (ADS)

Yli-Pelkonen, Vesa; Scott, Anna A.; Viippola, Viljami; Setälä, Heikki

2017-10-01

Trees and other vegetation absorb and capture air pollutants, leading to the common perception that they, and trees in particular, can improve air quality in cities and provide an important ecosystem service for urban inhabitants. Yet, there has been a lack of empirical evidence showing this at the local scale with different plant configurations and climatic regions. We studied the impact of urban park and forest vegetation on the levels of nitrogen dioxide (NO2) and ground-level ozone (O3) while controlling for temperature during early summer (May) using passive samplers in Baltimore, USA. Concentrations of O3 were significantly lower in tree-covered habitats than in adjacent open habitats, but concentrations of NO2 did not differ significantly between tree-covered and open habitats. Higher temperatures resulted in higher pollutant concentrations and NO2 and O3 concentration were negatively correlated with each other. Our results suggest that the role of trees in reducing NO2 concentrations in urban parks and forests in the Mid-Atlantic USA is minor, but that the presence of tree-cover can result in lower O3 levels compared to similar open areas. Our results further suggest that actions aiming at local air pollution mitigation should consider local variability in vegetation, climate, micro-climate, and traffic conditions.

Development of freeze dried vegetables

NASA Technical Reports Server (NTRS)

Larson, R. W.

1970-01-01

The development of freeze dried vegetables to be used in the Apollo food system is discussed. After the initial selection and screening of vegetables, several types of freeze dried vegetables were prepared in small batches. From these small batches, two vegetables were judged satisfactory for further testing and evaluation. These vegetables, mashed potatoes and asparagus, were subjected to storage at 100 deg plus or minus 5 F. for two weeks and then taste tested. The vegetables were also tested to determine if they complied with the microbiological requirements for Apollo food. The space food prototype production guide for the vegetables is submitted.

Survival and growth of foodborne pathogens in minimally processed vegetables at 4 and 15 °C.

PubMed

Tian, Jun-Qi; Bae, Young-Min; Choi, Na-Young; Kang, Dong-Hyun; Heu, Sunggi; Lee, Sun-Young

2012-01-01

We conducted this study to investigate the survival and growth of pathogens on fresh vegetables stored at 4 and 15 °C. Vegetables (romaine lettuce, iceberg lettuce, perilla leaves, and sprouts) were inoculated with 4 pathogens (Salmonella enterica serovar Typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7) and stored at 2 different temperatures for different periods of time (3, 6, 9, 12, and 15 d at 4 °C and 1, 2, 3, 5, and 7 d at 15 °C). Populations of the 4 pathogens tended to increase on all vegetables stored at 15 °C for 7 d. Populations of E. coli O157:H7 and S. Typhimurium increased significantly, by approximately 2 log₁₀ CFU/g, on loose and head lettuce stored at 15 °C for 1 d. No significant differences were observed in the growth of different pathogens on vegetables stored at 4 °C for 15 d. E. coli O157:H7 did not survive on sprouts stored at 15 or 4 °C. The survival and growth of food pathogens on fresh vegetables were very different depending on the pathogen type and storage temperature. Survivals and growth of pathogens on various vegetables at 4 and 15 °C were observed in this study. Survivals and growth of pathogens on vegetables were different depending on the pathogen type and storage temperature. Therefore, vegetables should be stored under refrigerated conditions (below 4 °C) prior to consumption. This recommendation may vary depending on the type of vegetable. © 2011 Institute of Food Technologists®

Effective Tree Scattering at L-Band

NASA Technical Reports Server (NTRS)

Kurum, Mehmet; ONeill, Peggy E.; Lang, Roger H.; Joseph, Alicia T.; Cosh, Michael H.; Jackson, Thomas J.

2011-01-01

For routine microwave Soil Moisture (SM) retrieval through vegetation, the tau-omega [1] model [zero-order Radiative Transfer (RT) solution] is attractive due to its simplicity and eases of inversion and implementation. It is the model used in baseline retrieval algorithms for several planned microwave space missions, such as ESA's Soil Moisture Ocean Salinity (SMOS) mission (launched November 2009) and NASA's Soil Moisture Active Passive (SMAP) mission (to be launched 2014/2015) [2 and 3]. These approaches are adapted for vegetated landscapes with effective vegetation parameters tau and omega by fitting experimental data or simulation outputs of a multiple scattering model [4-7]. The model has been validated over grasslands, agricultural crops, and generally light to moderate vegetation. As the density of vegetation increases, sensitivity to the underlying SM begins to degrade significantly and errors in the retrieved SM increase accordingly. The zero-order model also loses its validity when dense vegetation (i.e. forest, mature corn, etc.) includes scatterers, such as branches and trunks (or stalks in the case of corn), which are large with respect to the wavelength. The tau-omega model (when applied over moderately to densely vegetated landscapes) will need modification (in terms of form or effective parameterization) to enable accurate characterization of vegetation parameters with respect to specific tree types, anisotropic canopy structure, presence of leaves and/or understory. More scattering terms (at least up to first-order at L-band) should be included in the RT solutions for forest canopies [8]. Although not really suitable to forests, a zero-order tau-omega model might be applied to such vegetation canopies with large scatterers, but that equivalent or effective parameters would have to be used [4]. This requires that the effective values (vegetation opacity and single scattering albedo) need to be evaluated (compared) with theoretical definitions of these parameters. In a recent study [9], effective vegetation opacity of coniferous trees was compared with two independent estimates of the same parameter. First, a zero-order RT model was fitted to multiangular microwave emissivity data in a least-square sense to provide effective vegetation optical depth as done in spaceborne retrieval algorithms. Second, a ratio between radar backscatter measurements with a corner reflector under trees and in an open area was calculated to obtain measured tree propagation characteristics. Finally, the theoretical propagation constant was determined by forward scattering theorem using detailed measurements of size/angle distributions and dielectric constants of the tree constituents (trunk, branches, and needles). Results indicated that the effective attenuation values are smaller than but of similar magnitude to both the theoretical and measured values. This study will complement the previous work [9] and will focus on characterization of effective scattering albedo by assuming that effective vegetation opacity is same as theoretical opacity. The resultant effective albedo will not be the albedo of single forest canopy element anymore, but it becomes a global parameter, which depends on all the processes taking place within the canopy including multiple scattering as described.

Species-area curves indicate the importance of habitats' contributions to regional biodiversity

USGS Publications Warehouse

Chong, G.W.; Stohlgren, T.J.

2007-01-01

We examined species-area curves, species composition and similarity (Jaccard's coefficients), and species richness in 17 vegetation types to develop a composite index of a vegetation type's contribution to regional species richness. We collected data from 1 to 1000 m2 scales in 147 nested plots in Rocky Mountain National Park, Colorado, USA to compare three species-area curve models' abilities to estimate the number of species observed in each vegetation type. The log(species)-log(area) curve had the largest adjusted coefficients of determination (r2 values) in 12 of the 17 types, followed by the species-log(area) curve with five of the highest values. When the slopes of the curves were corrected for species overlap among plots with Jaccard's coefficients, the species-log(area) curves estimated values closest to those observed. We combined information from species-area curves and measures of heterogeneity with information on the area covered by each vegetation type and found that the types making the greatest contributions to regional biodiversity covered the smallest areas. This approach may provide an accurate and relatively rapid way to rank hotspots of plant diversity within regions of interest.

Remote sensing of plant functional types.

PubMed

Ustin, Susan L; Gamon, John A

2010-06-01

Conceptually, plant functional types represent a classification scheme between species and broad vegetation types. Historically, these were based on physiological, structural and/or phenological properties, whereas recently, they have reflected plant responses to resources or environmental conditions. Often, an underlying assumption, based on an economic analogy, is that the functional role of vegetation can be identified by linked sets of morphological and physiological traits constrained by resources, based on the hypothesis of functional convergence. Using these concepts, ecologists have defined a variety of functional traits that are often context dependent, and the diversity of proposed traits demonstrates the lack of agreement on universal categories. Historically, remotely sensed data have been interpreted in ways that parallel these observations, often focused on the categorization of vegetation into discrete types, often dependent on the sampling scale. At the same time, current thinking in both ecology and remote sensing has moved towards viewing vegetation as a continuum rather than as discrete classes. The capabilities of new remote sensing instruments have led us to propose a new concept of optically distinguishable functional types ('optical types') as a unique way to address the scale dependence of this problem. This would ensure more direct relationships between ecological information and remote sensing observations.

Effects of vegetation types on soil moisture estimation from the normalized land surface temperature versus vegetation index space

NASA Astrophysics Data System (ADS)

Zhang, Dianjun; Zhou, Guoqing

2015-12-01

Soil moisture (SM) is a key variable that has been widely used in many environmental studies. Land surface temperature versus vegetation index (LST-VI) space becomes a common way to estimate SM in optical remote sensing applications. Normalized LST-VI space is established by the normalized LST and VI to obtain the comparable SM in Zhang et al. (Validation of a practical normalized soil moisture model with in situ measurements in humid and semiarid regions [J]. International Journal of Remote Sensing, DOI: 10.1080/01431161.2015.1055610). The boundary conditions in the study were set to limit the point A (the driest bare soil) and B (the wettest bare soil) for surface energy closure. However, no limitation was installed for point D (the full vegetation cover). In this paper, many vegetation types are simulated by the land surface model - Noah LSM 3.2 to analyze the effects on soil moisture estimation, such as crop, grass and mixed forest. The locations of point D are changed with vegetation types. The normalized LST of point D for forest is much lower than crop and grass. The location of point D is basically unchanged for crop and grass.

Maximum entropy production, carbon assimilation, and the spatial organization of vegetation in river basins

PubMed Central

del Jesus, Manuel; Foti, Romano; Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio

2012-01-01

The spatial organization of functional vegetation types in river basins is a major determinant of their runoff production, biodiversity, and ecosystem services. The optimization of different objective functions has been suggested to control the adaptive behavior of plants and ecosystems, often without a compelling justification. Maximum entropy production (MEP), rooted in thermodynamics principles, provides a tool to justify the choice of the objective function controlling vegetation organization. The application of MEP at the ecosystem scale results in maximum productivity (i.e., maximum canopy photosynthesis) as the thermodynamic limit toward which the organization of vegetation appears to evolve. Maximum productivity, which incorporates complex hydrologic feedbacks, allows us to reproduce the spatial macroscopic organization of functional types of vegetation in a thoroughly monitored river basin, without the need for a reductionist description of the underlying microscopic dynamics. The methodology incorporates the stochastic characteristics of precipitation and the associated soil moisture on a spatially disaggregated framework. Our results suggest that the spatial organization of functional vegetation types in river basins naturally evolves toward configurations corresponding to dynamically accessible local maxima of the maximum productivity of the ecosystem. PMID:23213227

Effects of land preparation and artificial vegetation on soil moisture variation in a loess hilly catchment of China

NASA Astrophysics Data System (ADS)

Feng, Tianjiao; Wei, Wei; Chen, Liding; Yu, Yang

2017-04-01

In the dryland regions, soil moisture is the main factor to determine vegetation growth and ecosystem restoration. Land preparation and vegetation restoration are the principal means for improving soil water content(SWC). Thus, it is important to analyze the coupling role of these two means on soil moisture. In this study, soil moisture were monitored at a semi-arid loess hilly catchment of China, during the growing season of 2014 and 2015. Four different land preparation methods (level ditches, fish-scale pits, adverse grade tablelands and level benches)and vegetation types(Prunus armeniaca, Platycladus orientalis, Platycladus orientalis and Caragana microphylla) were included in the experimental design. Our results showed that: (1)Soil moisture content differed across land preparation types, which is higher for fish-scale pits and decreased in the order of level ditches and adverse grade tablelands.(2) Rainwater harvesting capacity of fish-scale pits is greater than adverse grade tablelands. However the water holding capacity is much higher at soils prepared with the adverse grade tablelands method than the ones prepared by fish-scale pits methods. (3) When land preparation method is similar, vegetation play a key role in soil moisture variation. For example, the mean soil moisture under a Platycladus orientalis field is 26.72% higher than a Pinus tabulaeformis field, with the same land preparation methods. (4)Soil moisture in deeper soil layers is more affected by changes in the vegetation cover while soil moisture in the shallower layers is more affected by the variation in the land preparation methods. Therefore, we suggest that vegetation types such as: Platycladus orientalisor as well as soil preparation methods such as level ditch and fish-scale pit are the most appropriate vegetation cover and land preparation methods for landscape restoration in semi-arid loess hilly area. This conclusion was made based on the vegetation type and land preparation with the best water-holding capacity.

On the use of tower-flux measurements to assess the performance of global ecosystem models

NASA Astrophysics Data System (ADS)

El Maayar, M.; Kucharik, C.

2003-04-01

Global ecosystem models are important tools for the study of biospheric processes and their responses to environmental changes. Such models typically translate knowledge, gained from local observations, into estimates of regional or even global outcomes of ecosystem processes. A typical test of ecosystem models consists of comparing their output against tower-flux measurements of land surface-atmosphere exchange of heat and mass. To perform such tests, models are typically run using detailed information on soil properties (texture, carbon content,...) and vegetation structure observed at the experimental site (e.g., vegetation height, vegetation phenology, leaf photosynthetic characteristics,...). In global simulations, however, earth's vegetation is typically represented by a limited number of plant functional types (PFT; group of plant species that have similar physiological and ecological characteristics). For each PFT (e.g., temperate broadleaf trees, boreal conifer evergreen trees,...), which can cover a very large area, a set of typical physiological and physical parameters are assigned. Thus, a legitimate question arises: How does the performance of a global ecosystem model run using detailed site-specific parameters compare with the performance of a less detailed global version where generic parameters are attributed to a group of vegetation species forming a PFT? To answer this question, we used a multiyear dataset, measured at two forest sites with contrasting environments, to compare seasonal and interannual variability of surface-atmosphere exchange of water and carbon predicted by the Integrated BIosphere Simulator-Dynamic Global Vegetation Model. Two types of simulations were, thus, performed: a) Detailed runs: observed vegetation characteristics (leaf area index, vegetation height,...) and soil carbon content, in addition to climate and soil type, are specified for model run; and b) Generic runs: when only observed climates and soil types at the measurement sites are used to run the model. The generic runs were performed for the number of years equal to the current age of the forests, initialized with no vegetation and a soil carbon density equal to zero.

A new map of standardized terrestrial ecosystems of Africa

USGS Publications Warehouse

Sayre, Roger G.; Comer, Patrick; Hak, Jon; Josse, Carmen; Bow, Jacquie; Warner, Harumi; Larwanou, Mahamane; Kelbessa, Ensermu; Bekele, Tamrat; Kehl, Harald; Amena, Ruba; Andriamasimanana, Rado; Ba, Taibou; Benson, Laurence; Boucher, Timothy; Brown, Matthew; Cress, Jill J.; Dassering, Oueddo; Friesen, Beverly A.; Gachathi, Francis; Houcine, Sebei; Keita, Mahamadou; Khamala, Erick; Marangu, Dan; Mokua, Fredrick; Morou, Boube; Mucina, Ladislav; Mugisha, Samuel; Mwavu, Edward; Rutherford, Michael; Sanou, Patrice; Syampungani, Stephen; Tomor, Bojoi; Vall, Abdallahi Ould Mohamed; Vande Weghe, Jean Pierre; Wangui, Eunice; Waruingi, Lucy

2013-01-01

Terrestrial ecosystems and vegetation of Africa were classified and mapped as part of a larger effort and global protocol (GEOSS – the Global Earth Observation System of Systems), which includes an activity to map terrestrial ecosystems of the earth in a standardized, robust, and practical manner, and at the finest possible spatial resolution. To model the potential distribution of ecosystems, new continental datasets for several key physical environment datalayers (including coastline, landforms, surficial lithology, and bioclimates) were developed at spatial and classification resolutions finer than existing similar datalayers. A hierarchical vegetation classification was developed by African ecosystem scientists and vegetation geographers, who also provided sample locations of the newly classified vegetation units. The vegetation types and ecosystems were then mapped across the continent using a classification and regression tree (CART) inductive model, which predicted the potential distribution of vegetation types from a suite of biophysical environmental attributes including bioclimate region, biogeographic region, surficial lithology, landform, elevation and land cover. Multi-scale ecosystems were classified and mapped in an increasingly detailed hierarchical framework using vegetation-based concepts of class, subclass, formation, division, and macrogroup levels. The finest vegetation units (macrogroups) classified and mapped in this effort are defined using diagnostic plant species and diagnostic growth forms that reflect biogeographic differences in composition and sub-continental to regional differences in mesoclimate, geology, substrates, hydrology, and disturbance regimes (FGDC, 2008). The macrogroups are regarded as meso-scale (100s to 10,000s of hectares) ecosystems. A total of 126 macrogroup types were mapped, each with multiple, repeating occurrences on the landscape. The modeling effort was implemented at a base spatial resolution of 90 m. In addition to creating several rich, new continent-wide biophysical datalayers describing African vegetation and ecosystems, our intention was to explore feasible approaches to rapidly moving this type of standardized, continent-wide, ecosystem classification and mapping effort forward.

Vulnerability of forest vegetation to anthropogenic climate change in China.

PubMed

Wan, Ji-Zhong; Wang, Chun-Jing; Qu, Hong; Liu, Ran; Zhang, Zhi-Xiang

2018-04-15

China has large areas of forest vegetation that are critical to biodiversity and carbon storage. It is important to assess vulnerability of forest vegetation to anthropogenic climate change in China because it may change the distributions and species compositions of forest vegetation. Based on the equilibrium assumption of forest communities across different spatial and temporal scales, we used species distribution modelling coupled with endemics-area relationship to assess the vulnerability of 204 forest communities across 16 vegetation types under different climate change scenarios in China. By mapping the vulnerability of forest vegetation to climate change, we determined that 78.9% and 61.8% of forest vegetation should be relatively stable in the low and high concentration scenarios, respectively. There were large vulnerable areas of forest vegetation under anthropogenic climate change in northeastern and southwestern China. The vegetation of subtropical mixed broadleaf evergreen and deciduous forest, cold-temperate and temperate mountains needleleaf forest, and temperate mixed needleleaf and broadleaf deciduous forest types were the most vulnerable under climate change. Furthermore, the vulnerability of forest vegetation may increase due to high greenhouse gas concentrations. Given our estimates of forest vegetation vulnerability to anthropogenic climate change, it is critical that we ensure long-term monitoring of forest vegetation responses to future climate change to assess our projections against observations. We need to better integrate projected changes of temperature and precipitation into climate-adaptive conservation strategies for forest vegetation in China. Copyright © 2017 Elsevier B.V. All rights reserved.

Fish assemblages in coastal lagoons in land-uplift succession: The relative importance of local and regional environmental gradients

NASA Astrophysics Data System (ADS)

Snickars, Martin; Sandström, Alfred; Lappalainen, Antti; Mattila, Johanna; Rosqvist, Kajsa; Urho, Lauri

2009-01-01

The assemblages of young-of-the-year fish were studied in coastal lagoons in an archipelago with post-glacial land-uplift, which affects environmental gradients at local and regional scale, i.e. lagoon habitat isolation and archipelago position, respectively. The categorisation of 40 undisturbed lagoons into nine habitat types based on habitat isolation and archipelago position was supported by clear relationships with spring temperature and total fish abundance. Rutilus rutilus, breams ( Abramis/Blicca sp.) and Perca fluviatilis were the most abundant and frequently occurring species. The fish assemblage differed among the nine habitat types. Rutilus rutilus, P. fluviatilis and breams were discriminating species in the majority of habitat types with low physical harshness, whereas Alburnus alburnus and Gasterosteus aculeatus increased their contributions in habitat types with high physical harshness. Rutilus rutilus and breams were thus common in lagoons with high habitat isolation situated in the inner archipelago. These lagoons were characterised by warm water and high vegetation coverage. Gasterosteus aculeatus was restricted to lagoons with low habitat isolation and exposure and low vegetation coverage, situated in the outer archipelago. Perca fluviatilis had the widest distribution of all species. The coverage of two macrophytes, Potamogeton perfoliatus and Zannichellia palustris, and salinity matched best the distance among habitat types. These habitat characteristics, as well as the fish abundances and assemblages differed most across the habitat types in the outer and mid archipelago zones and in the lowest habitat isolation. These patterns suggest that the structuring effect of habitat isolation increases along the archipelago gradient as differences between local and regional conditions increase. In the inner archipelago, overall low physical harshness induces homogeneous conditions and the habitat isolation is less important here than in the other zones. We suggest that this difference in the relative importance of the two gradients depending on the level of respective gradient ultimately forms these heterogeneous coastal habitats in a successional landscape. Rutilus rutilus and P. fluviatilis were responsible for large parts of the assemblage patterns. Although sympatric due to similar habitat requirements, differences in dispersal capability, competitive ability and predation vulnerability may add explanation to detected differences in distribution and abundance in these two species in an open system. Our results also stress the structuring role of vegetation in terms of total coverage and species composition, as these two aspects of macrophyte diversity may act as complementary habitat modifiers across gradients of physical harshness.

Expedient Metrics to Describe Plant Community Change Across Gradients of Anthropogenic Influence

NASA Astrophysics Data System (ADS)

Marcelino, José A. P.; Weber, Everett; Silva, Luís; Garcia, Patrícia V.; Soares, António O.

2014-11-01

Human influence associated with land use may cause considerable biodiversity losses, namely in oceanic islands such as the Azores. Our goal was to identify plant indicator species across two gradients of increasing anthropogenic influence and management (arborescent and herbaceous communities) and determine similarity between plant communities of uncategorized vegetation plots to those in reference gradients using metrics derived from R programming. We intend to test and provide an expedient way to determine the conservation value of a given uncategorized vegetation plot based on the number of native, endemic, introduced, and invasive indicator species present. Using the metric IndVal, plant taxa with a significant indicator value for each community type in the two anthropogenic gradients were determined. A new metric, ComVal, was developed to assess the similarity of an uncategorized vegetation plot toward a reference community type, based on (i) the percentage of pre-defined indicator species from reference communities present in the vegetation plots, and (ii) the percentage of indicator species, specific to a given reference community type, present in the vegetation plot. Using a data resampling approach, the communities were randomly used as training or validation sets to classify vegetation plots based on ComVal. The percentage match with reference community types ranged from 77 to 100 % and from 79 to 100 %, for herbaceous and arborescent vegetation plots, respectively. Both IndVal and ComVal are part of a suite of useful tools characterizing plant communities and plant community change along gradients of anthropogenic influence without a priori knowledge of their biology and ecology.

Improving the Projections of Vegetation Biogeography by Integrating Climate Envelope Models and Dynamic Global Vegetation Models

NASA Astrophysics Data System (ADS)

Case, M. J.; Kim, J. B.

2015-12-01

Assessing changes in vegetation is increasingly important for conservation planning in the face of climate change. Dynamic global vegetation models (DGVMs) are important tools for assessing such changes. DGVMs have been applied at regional scales to create projections of range expansions and contractions of plant functional types. Many DGVMs use a number of algorithms to determine the biogeography of plant functional types. One such DGVM, MC2, uses a series of decision trees based on bioclimatic thresholds while others, such as LPJ, use constraining emergent properties with a limited set of bioclimatic threshold-based rules. Although both approaches have been used widely, we demonstrate that these biogeography outputs perform poorly at continental scales when compared to existing potential vegetation maps. Specifically, we found that with MC2, the algorithm for determining leaf physiognomy is too simplistic to capture arid and semi-arid vegetation in much of the western U.S., as well as is the algorithm for determining the broadleaf and needleleaf mix in the Southeast. With LPJ, we found that the bioclimatic thresholds used to allow seedling establishment are too broad and fail to capture regional-scale biogeography of the plant functional types. In response, we demonstrate a new approach to determining the biogeography of plant functional types by integrating the climatic thresholds produced for individual tree species by a series of climate envelope models with the biogeography algorithms of MC2 and LPJ. Using this approach, we find that MC2 and LPJ perform considerably better when compared to potential vegetation maps.

COASTAL SUBMERGED VEGETATION: AQUATIC HABITAT RESEARCH

EPA Science Inventory

Aquatic vegetation is one of the most widespread and important types of aquatic habitat, in part because of the exceptional productivity of the plants. Aquatic vegetation also strongly influences local physical and chemical habitat conditions of significance to fish and shellfis...

The vegetation of the Grand River/Cedar River, Sioux, and Ashland Districts of the Custer National Forest: a habitat type classification.

Treesearch

Paul L. Hansen; George R. Hoffman

1988-01-01

A vegetation classification was developed, using the methods and concepts of Daubenmire, on the Ashland, Sioux, and Grand River/Cedar River Districts of the Custer National Forest. Of the 26 habitat types delimited and described, eight were steppe, nine shrub-steppe, four woodland, and five forest. Two community types also were described. A key to the habitat types and...

Mercury cycling in agricultural and managed wetlands of California: experimental evidence of vegetation-driven changes in sediment biogeochemistry and methylmercury production

USGS Publications Warehouse

Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark; Stricker, Craig A.; Agee, Jennifer L.; Kieu, Le H.; Kakouros, Evangelos

2014-01-01

The role of live vegetation in sediment methylmercury (MeHg) production and associated biogeochemistry was examined in three types of agricultural wetlands (domesticated or white rice, wild rice, and fallow fields) and adjacent managed natural wetlands (cattail- and bulrush or tule-dominated) in the Yolo Bypass region of California's Central Valley, USA. During the active growing season for each wetland, a vegetated:de-vegetated paired plot experiment demonstrated that the presence of live plants enhanced microbial rates of mercury methylation by 20 to 669% (median = 280%) compared to de-vegetated plots. Labile carbon exudation by roots appeared to be the primary mechanism by which microbial methylation was enhanced in the presence of vegetation. Pore-water acetate (pw[Ac]) decreased significantly with de-vegetation (63 to 99%) among all wetland types, and within cropped fields, pw[Ac] was correlated with both root density (r = 0.92) and microbial Hg(II) methylation (kmeth. r = 0.65). Sediment biogeochemical responses to de-vegetation were inconsistent between treatments for “reactive Hg” (Hg(II)R), as were reduced sulfur and sulfate reduction rates. Sediment MeHg concentrations in vegetated plots were double those of de-vegetated plots (median = 205%), due in part to enhanced microbial MeHg production in the rhizosphere, and in part to rhizoconcentration via transpiration-driven pore-water transport. Pore-water concentrations of chloride, a conservative tracer, were elevated (median = 22%) in vegetated plots, suggesting that the higher concentrations of other constituents around roots may also be a function of rhizoconcentration rather than microbial activity alone. Elevated pools of amorphous iron (Fe) in vegetated plots indicate that downward redistribution of oxic surface waters through transpiration acts as a stimulant to Fe(III)-reduction through oxidation of Fe(II)pools. These data suggest that vegetation significantly affected rhizosphere biogeochemistry through organic exudation and transpiration-driven concentration of pore-water constituents and oxidation of reduced compounds. While the relative role of vegetation varied among wetland types, macrophyte activity enhanced MeHg production.

Direct and indirect effects of land use on floral resources and flower-visiting insects across an urban landscape

USGS Publications Warehouse

Matteson, K.C.; Grace, James B.; Minor, E.S.

2013-01-01

Although urban areas are often considered to have uniformly negative effects on biodiversity, cities are most accurately characterized as heterogeneous mosaics of buildings, streets, parks, and gardens that include both ‘good’ and ‘bad’ areas for wildlife. However, to date, few studies have evaluated how human impacts vary in direction and magnitude across a heterogeneous urban landscape. In this study, we assessed the distribution of floral resources and flower-visiting insects across a variety of land uses in New York City. We visited both green spaces (e.g. parks, cemeteries) and heavily developed neighborhood blocks (e.g. with high or low density residential zoning) and used structural equation modeling (SEM) to evaluate the direct and indirect effects of median income, vegetation, and development intensity on floral resources and insects in both settings. Abundance and taxonomic richness of flower-visiting insects was significantly greater in green spaces than neighborhood blocks. The SEM results indicated that heavily-developed neighborhoods generally had fewer flower-visiting insects consistent with reductions in floral resources. However, some low-density residential neighborhoods maintained high levels of floral resources and flower-visiting insects. We found that the effects of surrounding vegetation on floral resources, and thus indirect effects on insects, varied considerably between green spaces and neighborhood blocks. Along neighborhood blocks, vegetation consisted of a mosaic of open gardens and sparsely distributed trees and had a positive indirect effect on flower-visiting insects. In contrast, vegetation in urban green spaces was associated with increased canopy cover and thus had a negative indirect effect on flower-visiting insects through reductions in floral resources. In both neighborhood blocks and green spaces, vegetation had a positive direct effect on flower-visiting insects independent of the influence of vegetation on floral resources. Our results demonstrate how inter-related components of an urban ecosystem can vary with respect to one another across a heterogeneous urban landscape, suggesting that it is inappropriate to generalize about urban systems as a whole without first addressing differences among component land use types.

Assessing onset and length of greening period in six vegetation types in Oaxaca, Mexico, using NDVI-precipitation relationships.

PubMed

Gómez-Mendoza, L; Galicia, L; Cuevas-Fernández, M L; Magaña, V; Gómez, G; Palacio-Prieto, J L

2008-07-01

Variations in the normalized vegetation index (NDVI) for the state of Oaxaca, in southern Mexico, were analyzed in terms of precipitation anomalies for the period 1997-2003. Using 10-day averages in NDVI data, obtained from AVHRR satellite information, the response of six types of vegetation to intra-annual and inter-annual fluctuations in precipitation were examined. The onset and temporal evolution of the greening period were studied in terms of precipitation variations through spectral analysis (coherence and phase). The results indicate that extremely dry periods, such as those observed in 1997 and 2001, resulted in low values of NDVI for much of Oaxaca, while good precipitation periods produced a rapid response (20-30 days of delay) from a stressed to a non-stressed condition in most vegetation types. One of these rapid changes occurred during the transition from dry to wet conditions during the summer of 1998. As in many parts of the tropics and subtropics, the NDVI reflects low frequency variations in precipitation on several spatial scales. Even after long dry periods (2001-2002), the various regional vegetation types are capable of recovering when a good rainy season takes place, indicating that vegetation types such as the evergreen forests in the high parts of Oaxaca respond better to rainfall characteristics (timing, amount) than to temperature changes, as is the case in most mid-latitudes. This finding may be relevant to prepare climate change scenarios for forests, where increases in surface temperature and precipitation anomalies are expected.

The impact of in-canopy wind attenuation formulations onheat flux estimation using the remote sensing-based two-source model for an open orchard canopy in southern Italy

USDA-ARS?s Scientific Manuscript database

For open orchard and vineyard canopies containing significant fractions of exposed soil (>50%), typical of Mediterranean agricultural regions, the energy balance of the vegetation elements is strongly influenced by heat exchange with the bare soil/substrate. For these agricultural systems a “two-sou...

Vegetation in group-selection openings: early trends

Treesearch

Philip M. McDonald; Paula J. Anderson; Gary O. Fiddler

1997-01-01

Nine openings that ranged from 0.2 to 1.6 acres and were grouped into small, medium, and large size classes comprised the initial group-selection cut on the Boggs Mountain State Forest in north central California. Five growing seasons after site preparation by pile and burn, 81 plant species in 35 families were present. Forbs, ferns, graminoids, manzanita, other shrubs...

Role of fire in regeneration from seed: Chapter 14

USGS Publications Warehouse

Keeley, Jon E.; Fotheringham, C.J.; Fenner, M.

2000-01-01

The effects of fire on seed germination and plant regeneration are discussed. Among the topics considered are the triggering of opening of serotinous fruits or cones by fire, the breaking of dormancy in seeds in the soil seed bank, the effects of smoke on germination, and the role of fire in initiating seedling recruitment by opening gaps in closed vegetation.

Statistical analysis of Thematic Mapper Simulator data for the geobotanical discrimination of rock types in southwest Oregon

NASA Technical Reports Server (NTRS)

Morrissey, L. A.; Weinstock, K. J.; Mouat, D. A.; Card, D. H.

1984-01-01

An evaluation of Thematic Mapper Simulator (TMS) data for the geobotanical discrimination of rock types based on vegetative cover characteristics is addressed in this research. A methodology for accomplishing this evaluation utilizing univariate and multivariate techniques is presented. TMS data acquired with a Daedalus DEI-1260 multispectral scanner were integrated with vegetation and geologic information for subsequent statistical analyses, which included a chi-square test, an analysis of variance, stepwise discriminant analysis, and Duncan's multiple range test. Results indicate that ultramafic rock types are spectrally separable from nonultramafics based on vegetative cover through the use of statistical analyses.

Evaluation of spatial, radiometric and spectral Thematic Mapper performance for coastal studies

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator)

1984-01-01

The effect different wetland plant canopies have upon observed reflectance in Thematic Mapper bands is examined. The three major vegetation canopy types (broadleaf, gramineous and leafless) produce unique spectral responses for a similar quantity of live biomass. Biomass estimates computed from spectral data were most similar to biomass estimates determined from harvest data when models developed for a specific canopy were used. Precise determination of regression coefficients for each canopy type and modeling changes in the coefficients with various combinations of canopy types are being tested. The multispectral band scanner vegetation index estimates are very similar to the vegetation index estimates.

Vegetation of Upper Coastal Plain Depression Wetlands: Environmental Templates and Wetland Dynamics Within A Landscape Framework

Treesearch

Diane De Steven; Maureen M. Toner

2004-01-01

Reference wetlands play an important role in efforts to protect wetlands and assess wetland condition. Because wetland vegetation integrates the influence of many ecological factors, a useful reference system would identify natural vegetation types and include models relating vegetation to important regional geomorphic, hydrologic, and geochemical properties. Across...