Science.gov

Sample records for wetland vegetation establishment

  1. Wetland vegetation establishment in L-Lake

    SciTech Connect

    Kroeger, S.R.

    1990-07-01

    Wetland vegetation was transplanted from PAR Pond to L-Lake between January and August, 1987. Approximately 100,000 individual plants representing over 40 species were transplanted along the southern shoreline. Three zones of vegetation were created: (1) submersed/floating-leaved, (2) emergent, (3) upper emergent/shrub. During the summers of 1987, 1988, 1989, the Savannah River Ecology Laboratory sampled the vegetation in 54 permanent transects located in planted (N=32) and unplanted areas (N=22). The 1989 vegetation data from L-Lake were compared to 1985 data from PAR Pond.

  2. Establishment of vegetation in constructed wetlands using biosolids and quarry fines

    SciTech Connect

    Danehy, T.P.; Zick, R.; Brenner, F.; Chmielewski, J.; Dunn, M.H.; Cooper, D.C.

    1999-07-01

    A common problem with constructing wetlands on abandoned mine sties is the lack of adequate soil needed to establish vegetation. One component of a full-scale passive treatment system built at Jennings Environmental Education Center in Brady Township, Butler County, PA addressed this issue through the development of a field trial to find an inexpensive alternative substrate for wetland plants. A simple soil recipe was followed which called for the mixing of an inorganic material with a nutrient-rich organic material. The inorganic constituent used was silt-size pond cleanings from a sand and gravel operation. The organic material used was a composted product made from exceptional-quality biosolids. Both soil components were obtained from local sources (less than 16 kilometers (12 miles) from the site) and mixed on site with a Caterpillar 963 track loader. The soil was used to construct a channel wetland 3 meters (10 feet) wide by 61 meters (200 feet) long. A seed mixture which contained 24 different wetland plant species native to western Pennsylvania was added to the substrate prior to releasing the water from the vertical flow system into the wetland. After one year, the vegetation was studied to determine the percent cover and species composition in order to document the effectiveness of this method of wetland construction. The preliminary results of this study indicate that this is an effective means to establish and sustain wetland vegetation. The addition of a fabricated substrate consisting of composted biosolids and silt can be a very effective method to establish dense and diverse vegetation in a constructed wetland.

  3. Vegetation establishment and evolution in four ponds that received sewage and wastewater in a portion of the Olezoa wetland complex, Yaounde, Cameroon, central Africa

    SciTech Connect

    Atekwana, E.A. . Dept. of Geology); Agendia, P.L. . Dept. of Plant Biology)

    1994-04-01

    A study of the spatial and temporal changes in the pattern and distribution of tropical wetland vegetation in four ponds that received sewage and wastewater discharge, was undertaken for a small wetland ecosystem in the Olezoa drainage basin in Yaounde, Cameroon. More than 25 years of nutrient loading has led to the eutrophication and subsequent establishment of wetland vegetation in these ponds. Estimated free water surface areas of the ponds in 1964, 1976, and 1986 and 1992 determined from digitized aerial photographs and field measurements suggests a decline of 70 to 100% in the pond surface areas due to invasion and colonization by plants. The rate of pond surface decline and vegetation development is correlated with the construction of sewage plants and the discharge of untreated sewage and wastewater into the ponds. The main wetland plants that are established in the ponds consist of aquatic species Nymphae lotus, Enhydra fluctuants, Pistia stratiotes, Commelina sp., Ipomea aquatica and terrestrial species Echinochloa sp., Thalia welwitschii, Polygonum senegalense, Leersia haxandra and Cyperus papyrus. The pattern of wetland plant succession that resulted within each pond is correlated to the timing, duration and magnitude of sewage and wastewater discharge into the wetland complex.

  4. Disturbance metrics predict a wetland Vegetation Index of Biotic Integrity

    USGS Publications Warehouse

    Stapanian, Martin A.; Mack, John; Adams, Jean V.; Gara, Brian; Micacchion, Mick

    2013-01-01

    Indices of biological integrity of wetlands based on vascular plants (VIBIs) have been developed in many areas in the USA. Knowledge of the best predictors of VIBIs would enable management agencies to make better decisions regarding mitigation site selection and performance monitoring criteria. We use a novel statistical technique to develop predictive models for an established index of wetland vegetation integrity (Ohio VIBI), using as independent variables 20 indices and metrics of habitat quality, wetland disturbance, and buffer area land use from 149 wetlands in Ohio, USA. For emergent and forest wetlands, predictive models explained 61% and 54% of the variability, respectively, in Ohio VIBI scores. In both cases the most important predictor of Ohio VIBI score was a metric that assessed habitat alteration and development in the wetland. Of secondary importance as a predictor was a metric that assessed microtopography, interspersion, and quality of vegetation communities in the wetland. Metrics and indices assessing disturbance and land use of the buffer area were generally poor predictors of Ohio VIBI scores. Our results suggest that vegetation integrity of emergent and forest wetlands could be most directly enhanced by minimizing substrate and habitat disturbance within the wetland. Such efforts could include reducing or eliminating any practices that disturb the soil profile, such as nutrient enrichment from adjacent farm land, mowing, grazing, or cutting or removing woody plants.

  5. FLUVIAL DISTURBANCE AND WETLAND VEGETATION DEVELOPMENT, UPPER MAIN STEM, WILLAMETTE RIVER, OREGON, USA

    EPA Science Inventory

    Hydrogeomorphic processes drive vegetation establishment, and promote development of diverse wetland and riparian types associated with lotic ecosystems. The main objective of this study was to estimate the rate and pattern of vegetation development on bars tracked since 1936, a...

  6. Evaluating Vegetation in the National Wetland Condition Assessment

    EPA Science Inventory

    Vegetation is a key biotic indicator of wetland ecological condition and forms a critical element of the USEPA 2011 National Wetland Condition Assessment. Data describing plant species composition and abundance, vegetation structure, and ground surface characteristics were colle...

  7. Does prescribed fire benefit wetland vegetation?

    USGS Publications Warehouse

    Flores, C.; Bounds, D.L.; Ruby, D.E.

    2011-01-01

    The effects of fire on wetland vegetation in the mid-Atlantic region of the United States are poorly known, despite the historical use of fire by federal, state, and private landowners in the Chesapeake Bay Region. Prescribed fire is widely used by land managers to promote vegetation that is beneficial to migratory waterfowl, muskrats, and other native wildlife and to reduce competition from less desirable plant species. We compared vegetative response to two fire rotations, annual burns and 3-year burns, and two control sites, Control 1 and Control 2. We tested the effects of fire within six tidal marsh wetlands at Blackwater National Wildlife Refuge and Fishing Bay Wildlife Management Area in Maryland. We examined changes in total live biomass (all species), total stem density, litter, and changes in live biomass and stem density of four dominant wetland plant species (11 variables). Our results suggest that annual prescribed fires will decrease the accumulation of litter, increase the biomass and stem densities of some wetland plants generally considered less desirable for wildlife, and have little or no effect on other wetland plants previously thought to benefit from fire. ?? 2011 US Government.

  8. Simulation of wetlands forest vegetation dynamics

    USGS Publications Warehouse

    Phipps, R.L.

    1979-01-01

    A computer program, SWAMP, was designed to simulate the effects of flood frequency and depth to water table on southern wetlands forest vegetation dynamics. By incorporating these hydrologic characteristics into the model, forest vegetation and vegetation dynamics can be simulated. The model, based on data from the White River National Wildlife Refuge near De Witt, Arkansas, "grows" individual trees on a 20 x 20-m plot taking into account effects on the tree growth of flooding, depth to water table, shade tolerance, overtopping and crowding, and probability of death and reproduction. A potential application of the model is illustrated with simulations of tree fruit production following flood-control implementation and lumbering. ?? 1979.

  9. Vegetation survey of PEN Branch wetlands

    SciTech Connect

    Not Available

    1991-01-01

    A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizes a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.

  10. Effects of dominant species on vegetation change in Carolina bay wetlands following a multi-year drought.

    SciTech Connect

    Mulhouse, John, M.; De Steven, Diane; Lide, Robert, F.; Sharitz, Rebecca, R.

    2005-05-01

    Wetland vegetation is strongly dependent upon climate-influenced hydrologic conditions, and plant composition responds in generally consistent ways to droughts. However, the extent of species composition change during drought may be influenced by the pre-existing structure of wetland vegetation. We characterized the vegetation of ten herbaceous Carolina bay wetlands on the South Carolina Upper Coastal Plain during a period of average rainfall and again near the end of a four-year drought. We hypothesized that, as a group, bays dominated by less robust plant species (characteristic of open-water pond and depression meadow vegetation types) would show greater compositional change than bays dominated by dense, robust-form clonal graminoids (characteristic of grass and sedge marsh vegetation types). Aquatic species decreased during the drought in all wetlands, regardless of vegetation group. Compared to grass/sedge marshes, pond/meadow wetlands acquired more species, particularly non-wetland species, during the drought. Pond/meadow wetlands also had greater increases in the abundances of species that require unflooded conditions to establish. Prior to the drought, all wetlands were ponded almost continuously, but during drought the pond/meadow wetlands had shorter and more variable hydroperiods than the grass/sedge marshes. Thus, vegetation change may be partly confounded with hydrologic conditions that provide greater opportunities for species recruitment in pond/meadow bays. The results suggest that Carolina bay vegetation dynamics may differ as a function of dominant vegetation and climate driven variation in wetland hydrologic condition.

  11. Metric Similarity in Vegetation-Based Wetland Assessment Methods

    EPA Science Inventory

    Wetland vegetation is a recognized indicator group for wetland assessments, but until recently few published protocols used plant-based indicators. To examine the proliferation of such protocols since 1999, this report reviewed 20 published index of biotic integrity (IBI) type p...

  12. TerraSAR-X dual-pol time-series for mapping of wetland vegetation

    NASA Astrophysics Data System (ADS)

    Betbeder, Julie; Rapinel, Sébastien; Corgne, Samuel; Pottier, Eric; Hubert-Moy, Laurence

    2015-09-01

    Mapping vegetation formations at a fine scale is crucial for assessing wetland functions and for better landscape management. Identification and characterization of vegetation formations is generally conducted at a fine scale using ecological ground surveys, which are limited to small areas. While optical remotely sensed imagery is limited to cloud-free periods, SAR time-series are used more extensively for wetland mapping and characterization using the relationship between distribution of vegetation formations and flood duration. The aim of this study was to determine the optimal number and key dates of SAR images to be classified to map wetland vegetation formations at a 1:10,000 scale. A series of eight dual-polarization TerraSAR-X images (HH/VV) was acquired in 2013 during dry and wet seasons in temperate climate conditions. One polarimetric parameter was extracted first, the Shannon entropy, which varies with wetland flooding status and vegetation roughness. Classification runs of all the possible combinations of SAR images using different k (number of images) subsets were performed to determine the best combinations of the Shannon entropy images to identify wetland vegetation formations. The classification runs were performed using Support Vector Machine techniques and were then analyzed using the McNemar test to investigate significant differences in the accuracy of all classification runs based on the different image subsets. The results highlight the relevant periods (i.e. late winter, spring and beginning of summer) for mapping vegetation formations, in accordance with ecological studies. They also indicate that a relationship can be established between vegetation formations and hydrodynamic processes with a short time-series of satellite images (i.e. 5 dates). This study introduces a new approach for herbaceous wetland monitoring using SAR polarimetric imagery. This approach estimates the number and key dates required for wetland management (e

  13. Changes in the Vegetation Cover in a Constructed Wetland at Argonne National Laboratory, Illinois

    SciTech Connect

    Bergman, C.L.; LaGory, K.

    2004-01-01

    Wetlands are valuable resources that are disappearing at an alarming rate. Land development has resulted in the destruction of wetlands for approximately 200 years. To combat this destruction, the federal government passed legislation that requires no net loss of wetlands. The United States Army Corps of Engineers (USACE) is responsible for regulating wetland disturbances. In 1991, the USACE determined that the construction of the Advanced Photon Source at Argonne National Laboratory would damage three wetlands that had a total area of one acre. Argonne was required to create a wetland of equal acreage to replace the damaged wetlands. For the first five years after this wetland was created (1992-1996), the frequency of plant species, relative cover, and water depth was closely monitored. The wetland was not monitored again until 2002. In 2003, the vegetation cover data were again collected with a similar methodology to previous years. The plant species were sampled using quadrats at randomly selected locations along transects throughout the wetland. The fifty sampling locations were monitored once in June and percent cover of each of the plant species was determined for each plot. Furthermore, the extent of standing water in the wetland was measured. In 2003, 21 species of plants were found and identified. Eleven species dominated the wetland, among which were reed canary grass (Phalaris arundinacea), crown vetch (Coronilla varia), and Canada thistle (Cirsium arvense). These species are all non-native, invasive species. In the previous year, 30 species were found in the same wetland. The common species varied from the 2002 study but still had these non-native species in common. Reed canary grass and Canada thistle both increased by more than 100% from 2002. Unfortunately, the non-native species may be contributing to the loss of biodiversity in the wetland. In the future, control measures should be taken to ensure the establishment of more desired native species.

  14. 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.

  15. Coevolution of hydraulic, soil and vegetation processes in estuarine wetlands

    NASA Astrophysics Data System (ADS)

    Trivisonno, Franco; Rodriguez, Jose F.; Riccardi, Gerardo; Saco, Patricia; Stenta, Hernan

    2014-05-01

    Estuarine wetlands of south eastern Australia, typically display a vegetation zonation with a sequence mudflats - mangrove forest - saltmarsh plains from the seaward margin and up the topographic gradient. Estuarine wetlands are among the most productive ecosystems in the world, providing unique habitats for fish and many terrestrial species. They also have a carbon sequestration capacity that surpasess terrestrial forest. Estuarine wetlands respond to sea-level rise by vertical accretion and horizontal landward migration, in order to maintain their position in the tidal frame. In situations in which buffer areas for landward migration are not available, saltmarsh can be lost due to mangrove encroachment. As a result of mangrove invasion associated in part with raising estuary water levels and urbanisation, coastal saltmarsh in parts of south-eastern Australia has been declared an endangered ecological community. Predicting estuarine wetlands response to sea-level rise requires modelling the coevolving dynamics of water flow, soil and vegetation. This paper presents preliminary results of our recently developed numerical model for wetland dynamics in wetlands of the Hunter estuary of NSW. The model simulates continuous tidal inflow into the wetland, and accounts for the effect of varying vegetation types on flow resistance. Coevolution effects appear as vegetation types are updated based on their preference to prevailing hydrodynamic conditions. The model also considers that accretion values vary with vegetation type. Simulations are driven using local information collected over several years, which includes estuary water levels, accretion rates, soil carbon content, flow resistance and vegetation preference to hydraulic conditions. Model results predict further saltmarsh loss under current conditions of moderate increase of estuary water levels.

  16. VEGETATION DEVELOPMENT OF THREE CONSTRUCTED WETLANDS RECEIVING AGRICULTURAL RUN-OFF AND SUBSURFACE DRAINAGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Case studies of terrestrial and aquatic vegetation development in three constructed wetlands receiving agricultural drainage were conducted. Surveys were completed on three Wetland Reservoir Subirrigation System (WRSIS) constructed wetlands located in Defiance, Fulton, and Van Wert counties in north...

  17. Reestablishment of wetland vegetation on gas pipeline rights-of-way in six different wetland ecosystems

    SciTech Connect

    Zimmerman, R.E. Shem, L.; Wilkey, P.L.; Van Dyke, G.D.; Hackney, C.; Gowdy, M.

    1992-05-01

    Vegetational surveys were carried out to compare reestablished vegetation on pipeline rights-of-way (ROWS) with that in adjacent natural ecosystems undisturbed by pipeline installation. Six sites of various ages were surveyed in ecosystems ranging from coastal marsh to forested wetland. At all sites except one, both the number and the percentage of wetland species on the ROW approximated or exceeded those in the adjacent natural area. In four ecosystems, the vegetation on the ROW was limited to a herbaceous layer by ROW maintenance; thus, the ROWs often involved a complex of species quite different from that found in the adjacent ecosystems.

  18. Vegetation of wetlands of the prairie pothole region

    USGS Publications Warehouse

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

    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

  19. The present and future role of coastal wetland vegetation in protecting shorelines: Answering recent challenges to the paradigm

    USGS Publications Warehouse

    Gedan, Keryn B.; Kirwan, Matthew L.; Wolanski, Eric; Barbier, Edward B.; Silliman, Brian R.

    2011-01-01

    For more than a century, coastal wetlands have been recognized for their ability to stabilize shorelines and protect coastal communities. However, this paradigm has recently been called into question by small-scale experimental evidence. Here, we conduct a literature review and a small meta-analysis of wave attenuation data, and we find overwhelming evidence in support of established theory. Our review suggests that mangrove and salt marsh vegetation afford context-dependent protection from erosion, storm surge, and potentially small tsunami waves. In biophysical models, field tests, and natural experiments, the presence of wetlands reduces wave heights, property damage, and human deaths. Meta-analysis of wave attenuation by vegetated and unvegetated wetland sites highlights the critical role of vegetation in attenuating waves. Although we find coastal wetland vegetation to be an effective shoreline buffer, wetlands cannot protect shorelines in all locations or scenarios; indeed large-scale regional erosion, river meandering, and large tsunami waves and storm surges can overwhelm the attenuation effect of vegetation. However, due to a nonlinear relationship between wave attenuation and wetland size, even small wetlands afford substantial protection from waves. Combining man-made structures with wetlands in ways that mimic nature is likely to increase coastal protection. Oyster domes, for example, can be used in combination with natural wetlands to protect shorelines and restore critical fishery habitat. Finally, coastal wetland vegetation modifies shorelines in ways (e.g. peat accretion) that increase shoreline integrity over long timescales and thus provides a lasting coastal adaptation measure that can protect shorelines against accelerated sea level rise and more frequent storm inundation. We conclude that the shoreline protection paradigm still stands, but that gaps remain in our knowledge about the mechanistic and context-dependent aspects of shoreline

  20. Early vegetational changes on a forested wetland constructed for mitigation

    USGS Publications Warehouse

    Perry, M.C.; Osenton, P.C.; Sibrel, C.B.

    1997-01-01

    Changes in vegetation were studied on 15 acres of a 35 acre forested wetland created as a mitigation site in Anne Arundel County, Maryland during 1994-96. Meter-square sampling on four different hydrologic elevations determined that grasses initially dominated the area, but decreased from 59 percent in 1994 to 51 percent in 1995 and 30 percent in 1996. Herbaceous non-grass plants (forbs) increased from 19 percent to 56 percent in the three-year period. Area with no plant cover decreased from 21 percent in 1994 to 11 percent in 1995, and 10 percent in 1996. Woody plants comprised 2 percent of the cover in 1994, increased to 4 percent in 1995, and remained at 4 percent in 1996. The increase of woody plants was mainly from natural regeneration (pioneer) plants. Monitoring of the transplanted trees and shrubs indicated 35 percent mortality and little growth of surviving plants. The pioneer woody plant forming most of the cover was black willow (Salix nigra). Differences in the vegetation were observed among the four elevations, although no differences were observed for the major vegetation classes between plots that were planted and those that were not planted with woody plants. Dominant grass species was redtop (Agrostis stolonifera), which comprised 51 percent of the cover in 1994 and 42 percent cover in 1995 and 23 percent in 1996. Other species that were common were bush clover (Lespedeza cuneata), Japanese clover (Lespedeza striata) and flat pea (Lathyrus sylvestris). All four of these dominant species were part of the original seed mixtures that were seeded on the site. A total of 134 species of plants was recorded on the site indicating a fairly diverse community for a newly established habitat.

  1. Classification of wetlands vegetation using small scale color infrared imagery

    NASA Technical Reports Server (NTRS)

    Williamson, F. S. L.

    1975-01-01

    A classification system for Chesapeake Bay wetlands was derived from the correlation of film density classes and actual vegetation classes. The data processing programs used were developed by the Laboratory for the Applications of Remote Sensing. These programs were tested for their value in classifying natural vegetation, using digitized data from small scale aerial photography. Existing imagery and the vegetation map of Farm Creek Marsh were used to determine the optimal number of classes, and to aid in determining if the computer maps were a believable product.

  2. Wind-driven water motions in wetlands with emergent vegetation

    NASA Astrophysics Data System (ADS)

    Tse, Ian C.; Poindexter, Cristina M.; Variano, Evan A.

    2016-04-01

    Wetland biogeochemical transformations are affected by flow and mixing in wetland surface water. We investigate the influence of wind on wetland water flow by simultaneously measuring wind and surface water velocities in an enclosed freshwater wetland during 1 day of strong-wind conditions. Water velocities are measured using a Volumetric Particle Imager while wind velocities are measured via sonic-anemometer. Our measurements indicate that the wind interacting with the vegetation canopy generates coherent billows and that these billows are the dominant source of momentum into the wetland water column. Spectral analysis of velocity time series shows that the spectral peak in water velocity is aligned with the spectral peak of in-canopy wind velocity, and that this peak corresponds with the Kelvin-Helmholtz billow frequency predicted by mixing layer theory. We also observe a strong correlation in the temporal pattern of velocity variance in the air and water, with high variance events having similar timing and duration both above and below the air-water interface. Water-side variance appears coupled with air-side variance at least down to 5 cm, while the theoretical Stokes' solution predicts momentum transfer down to only 2 mm assuming transfer via molecular viscosity alone. This suggests that the wind-driven flow contributed to significant mixing in the wetland water column.

  3. Vegetation establishment in convectively accelerated streams

    NASA Astrophysics Data System (ADS)

    Crouzy, B.; McLelland, S. J.; Molnar, P.; Camporeale, C.; Perona, P.

    2013-12-01

    We study the conditions for vegetation establishment within river reaches with converging boundaries. Common to many such rivers worldwide is the existence of a limiting front (e.g., Figure 1a) beyond which all the riverbed vegetation is uprooted by flooding events. There are however exceptions, which leads to an interesting ecomorphodynamic problem (existence and position of the front). We use a theoretical 1-D framework based on morphodynamic equations modified in order to account for the presence of vegetation (Perona et al., submitted), and obtain the link between the position of the vegetated front and river eco-hydraulic variables under steady and unsteady conditions. We apply our framework to a number of flume experiments (unsteady flow) where Avena sativa L. (common oat) seedlings grow subject to periodic flow disturbances within a convergent flume channel (Figure 1b). We find that depending on the outcome of the competition between hydrological and biological processes there is either a limiting spatial front within the convergent section beyond which vegetation cannot survive, or vegetation colonizes the entire riverbed. The existence and the position of the front depend on the ability for vegetation to take root efficiently and withstand uprooting by the flow of the convectively accelerated stream (Crouzy et al., in press). The active role of vegetation and of unit streampower in this particular ecomorphodynamic process are then discussed in relation to the conceptual model of Gurnell and Petts (2006), and under the light of our theoretical and experimental results. REFERENCES - Crouzy, B., K. Edmaier, N. Pasquale and P. Perona (in press). Impact of floods on the statistical distribution of riverbed vegetation. Geomorphology doi:10.1016/j.geomorph.2012.09.013. - Gurnell A., Petts G. (2006). Trees as riparian engineers: The Tagliamento River, Italy. Earth Surface Processes and Landforms, 31: 1558--1574. - Perona, P., B. Crouzy, S. Mc Lelland, P. Molnar

  4. Boron in Pariette Wetland Sediments, Aquatic Vegetation & Benthic Organisms

    NASA Astrophysics Data System (ADS)

    Vasudeva, P.; Jones, C. P.; Powelson, D.; Jacobson, A. R.

    2015-12-01

    The Pariette Wetlands are comprised of 20 ponds located in Utah's Uintah Basin. Boron concentration in the Pariette Wetlands have been observed to exceed the total maximum daily limit of 750 µg L-1. Considering water flow in and out of the wetlands, boron is accumulating within the wetlands where it is sorbed to sediments and bioconcentrated by wetland plant and macro invertebrates. Since boron is an avian teratogen, an estimate of boron ingestion exposure is warranted. Samples from 3 of the 23 Pariette Wetland ponds with one pond near the inlet, one near the outlet, and one in the middle were collected. Five sampling points were designated along a 100 m transect of each pond. At each sampling point duplicate (or triplicate) samples of water, sediments, benthic organisms and wetland vegetation were collected. The sediments were collected with a KB-corer and divided at depths of 0-2 cm, 2-7 cm, and 7+ cm from the sediment surface. Sample splits were sent to the USU Bug lab for identification of invertebrate species. Whenever this transect was not intercepting vegetation, 2-3 additional sample sites were identified at the pond within stands of representative vegetation where bird nests are located. The plant parts used for boron analyses will include seeds, shoot and roots of vascular plants, as well as algae or duckweeds skimmed from the surface. Samples were processed within 2 days of collection. Water samples filtered through a 0.45 μ membrane filter were analyzed for DOC, pH and ECe. The dried and washed vegetation samples were ground and stored. The benthic organisms and macro invertebrates were netted at the water surface. The dried samples were weighed, ground and stored. Samples were weighed, oven dried and reweighed. For plant and macro-invertebrate samples, a nitric and hydrogen peroxide digestion procedure is used to dissolve environmentally available elements. The Hot Water extraction and DTPA-Sorbitol extraction were compared to estimate wetland plant

  5. AIS-2 spectra of California wetland vegetation

    NASA Technical Reports Server (NTRS)

    Gross, Michael F.; Ustin, Susan L.; Klemas, Vytautas

    1987-01-01

    Spectral data gathered by Airborne Imaging Spectrometers-2 from wetlands were analyzed. Spectra representing stands of green Salicornia virginica, green Sesuvium verrucosum, senescing Distichlis spicata, a mixture of senescing Scirpus acutus and Scirpus californicus, senescing Scirpus paludosus, senescent S. paludosus, mowed senescent S. paludosus, and soil were isolated. No difference among narrowband spectral reflectance of the cover types was apparent between 0.8 to 1.6 micron. There were, however, broadband differences in brightness. These differences were sufficient to permit a fairly accurate decomposition of the image into its major cover type components using a procedure that assumes an additive linear mixture of surface spectra.

  6. Plant community, primary productivity, and environmental conditions following wetland re-establishment in the Sacramento-San Joaquin Delta, California

    USGS Publications Warehouse

    Miller, R.L.; Fujii, R.

    2010-01-01

    Wetland restoration can mitigate aerobic decomposition of subsided organic soils, as well as re-establish conditions favorable for carbon storage. Rates of carbon storage result from the balance of inputs and losses, both of which are affected by wetland hydrology. We followed the effect of water depth (25 and 55 cm) on the plant community, primary production, and changes in two re-established wetlands in the Sacramento San-Joaquin River Delta, California for 9 years after flooding to determine how relatively small differences in water depth affect carbon storage rates over time. To estimate annual carbon inputs, plant species cover, standing above- and below-ground plant biomass, and annual biomass turnover rates were measured, and allometric biomass models for Schoenoplectus (Scirpus) acutus and Typha spp., the emergent marsh dominants, were developed. As the wetlands developed, environmental factors, including water temperature, depth, and pH were measured. Emergent marsh vegetation colonized the shallow wetland more rapidly than the deeper wetland. This is important to potential carbon storage because emergent marsh vegetation is more productive, and less labile, than submerged and floating vegetation. Primary production of emergent marsh vegetation ranged from 1.3 to 3.2 kg of carbon per square meter annually; and, mid-season standing live biomass represented about half of the annual primary production. Changes in species composition occurred in both submerged and emergent plant communities as the wetlands matured. Water depth, temperature, and pH were lower in areas with emergent marsh vegetation compared to submerged vegetation, all of which, in turn, can affect carbon cycling and storage rates. ?? Springer Science+Business Media B.V. 2009.

  7. The role of hydrochory in structuring riparian and wetland vegetation.

    PubMed

    Nilsson, Christer; Brown, Rebecca L; Jansson, Roland; Merritt, David M

    2010-11-01

    Hydrochory, or the passive dispersal of organisms by water, is an important means of propagule transport, especially for plants. During recent years, knowledge about hydrochory and its ecological consequences has increased considerably and a substantial body of literature has been produced. Here, we review this literature and define the state of the art of the discipline. A substantial proportion of species growing in or near water have propagules (fruits, seeds or vegetative units) able to disperse by water, either floating, submerged in flowing water, or with the help of floating vessels. Hydrochory can enable plants to colonize sites out of reach with other dispersal vectors, but the timing of dispersal and mechanisms of establishment are important for successful establishment. At the population level, hydrochory may increase the effective size and longevity of populations, and control their spatial configuration. Hydrochory is also an important source of species colonizing recruitment-limited riparian and wetland communities, contributing to maintenance of community species richness. Dispersal by water may even influence community composition in different landscape elements, resulting in landscape-level patterns. Genetically, hydrochory may reduce spatial aggregation of genetically related individuals, lead to high gene flow among populations, and increase genetic diversity in populations receiving many propagules. Humans have impacted hydrochory in many ways. For example, dams affect hydrochory by reducing peak flows and hence dispersal capacity, altering the timing of dispersal, and by presenting physical barriers to dispersal, with consequences for riverine plant communities. Hydrochory has been inferred to be an important vector for the spread of many invasive species, but there is also the potential for enhancing ecosystem restoration by improving or restoring water dispersal pathways. Climate change may alter the role of hydrochory by modifying the

  8. Vegetation Changes and Partitioning of Selenium in 4-Year-Old Constructed Wetlands Treating Agricultural Drainage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The knowledge of vegetation management and the partitioning of selenium (Se) in treatment wetlands is essential for long-term effective operation of constructed wetlands treating Se-laden agricultural tile-drainage water in the San Joaquin Valley, California. Vegetation changes in six vegetated wetl...

  9. Texture classification of vegetation cover in high altitude wetlands zone

    NASA Astrophysics Data System (ADS)

    Wentao, Zou; Bingfang, Wu; Hongbo, Ju; Hua, Liu

    2014-03-01

    The aim of this study was to investigate the utility of datasets composed of texture measures and other features for the classification of vegetation cover, specifically wetlands. QUEST decision tree classifier was applied to a SPOT-5 image sub-scene covering the typical wetlands area in Three River Sources region in Qinghai province, China. The dataset used for the classification comprised of: (1) spectral data and the components of principal component analysis; (2) texture measures derived from pixel basis; (3) DEM and other ancillary data covering the research area. Image textures is an important characteristic of remote sensing images; it can represent spatial variations with spectral brightness in digital numbers. When the spectral information is not enough to separate the different land covers, the texture information can be used to increase the classification accuracy. The texture measures used in this study were calculated from GLCM (Gray level Co-occurrence Matrix); eight frequently used measures were chosen to conduct the classification procedure. The results showed that variance, mean and entropy calculated by GLCM with a 9*9 size window were effective in distinguishing different vegetation types in wetlands zone. The overall accuracy of this method was 84.19% and the Kappa coefficient was 0.8261. The result indicated that the introduction of texture measures can improve the overall accuracy by 12.05% and the overall kappa coefficient by 0.1407 compared with the result using spectral and ancillary data.

  10. Coevolution of hydrodynamics, vegetation and channel evolution in wetlands of a semi-arid floodplain

    NASA Astrophysics Data System (ADS)

    Seoane, Manuel; Rodriguez, Jose Fernando; Rojas, Steven Sandi; Saco, Patricia Mabel; Riccardi, Gerardo; Saintilan, Neil; Wen, Li

    2015-04-01

    The Macquarie Marshes are located in the semi-arid region in north western NSW, Australia, and constitute part of the northern Murray-Darling Basin. The Marshes are comprised of a system of permanent and semi-permanent marshes, swamps and lagoons interconnected by braided channels. The wetland complex serves as nesting place and habitat for many species of water birds, fish, frogs and crustaceans, and portions of the Marshes was listed as internationally important under the Ramsar Convention. Some of the wetlands have undergone degradation over the last four decades, which has been attributed to changes in flow management upstream of the marshes. Among the many characteristics that make this wetland system unique is the occurrence of channel breakdown and channel avulsion, which are associated with decline of river flow in the downstream direction typical of dryland streams. Decrease in river flow can lead to sediment deposition, decrease in channel capacity, vegetative invasion of the channel, overbank flows, and ultimately result in channel breakdown and changes in marsh formation. A similar process on established marshes may also lead to channel avulsion and marsh abandonment, with the subsequent invasion of terrestrial vegetation. All the previous geomorphological evolution processes have an effect on the established ecosystem, which will produce feedbacks on the hydrodynamics of the system and affect the geomorphology in return. In order to simulate the complex dynamics of the marshes we have developed an ecogeomorphological modelling framework that combines hydrodynamic, vegetation and channel evolution modules and in this presentation we provide an update on the status of the model. The hydrodynamic simulation provides spatially distributed values of inundation extent, duration, depth and recurrence to drive a vegetation model based on species preference to hydraulic conditions. It also provides velocities and shear stresses to assess geomorphological

  11. Vegetation establishment success in restored carolina bay depressions on the Savannah River Site, South Carolina - phase one.

    SciTech Connect

    Sharitz, Rebecca, A.; Mulhouse, John, M.

    2004-05-01

    Successful wetlands restoration must re-establish or enhance three parameters: wetland hydrology, hydric soils, and hydrophytic vegetation (Mitsch and Gosselink 2000). On the Savannah River Site, South Carolina, restoration of small Carolina bay depression-wetlands was initiated in FY 2001 to provide wetland acreage for mitigation banking (US DOE 1997). Sixteen small depressions that had historically been drained for agricultural purposes were selected for restoration, and an additional four were initially chosen to serve as non-restored controls. Restoration treatments included plugging the existing ditches to increase water volume retention and wetland hydroperiod and clear-cutting removal of woody vegetation in the interiors. Planned endpoints of the restoration were herbaceous meadow and forested savanna bay interiors, and pine savanna and pine/hardwood forested bay margins (Barton and Singer 2001). To promote forested savanna interiors, saplings of bald cypress and swamp tupelo were planted following removal of the woody species.

  12. Vegetation community composition in wetlands created following oil sand mining in Alberta, Canada.

    PubMed

    Roy, Marie-Claude; Foote, Lee; Ciborowski, Jan J H

    2016-05-01

    Reclaiming wetlands following open pit mining for industrial oil sand extraction is challenging due to the physical and chemical conditions of the post-mined landscape. The aim of our study was to examine and compare the influence of oil sands process water (OSPW) and material (fine fluid tails or FFT) on the plant community composition of created wetlands. Compared to created-unamended and natural wetlands, the created wetlands amended with OSPW and/or FFT (created-tailings wetlands) had significantly higher water salinity, conductivity, dissolved oxygen concentration and lower oxidative-reductive potential. Water chemistry parameters of created-unamended did not differ significantly from those of natural wetlands. The sediment of created wetlands had significantly less moisture, total nitrogen, and organic content than the natural wetlands. The application of OSPW/FFT in created wetlands will likely lead to initial vegetation composition atypical of natural regional wetlands. For the objective of reclaiming vegetation composition to the status of natural regional wetlands, unamended wetlands were the best reclamation option, based on the physical and chemical parameters measured. Despite being the favored reclamation option, created-unamended wetlands' physical and chemical characteristics remain atypical of natural wetlands. Most significantly, the basin morphometry of created wetlands was significantly different from that of naturally-formed wetlands in the region, and this appears to partly explain difference in vegetation composition. We also demonstrate that species richness alone is not a useful measure in wetland monitoring. Instead, plant community composition is a better indicator of wetland conditions. PMID:26921562

  13. Carbon gas fluxes in re-established wetlands on organic soils differ relative to plant community and hydrology

    USGS Publications Warehouse

    Miller, Robin L.

    2011-01-01

    We measured CO2 and CH4 fluxes for 6 years following permanent flooding of an agriculturally managed organic soil at two water depths (~25 and ~55 cm standing water) in the Sacramento–San Joaquin Delta, California, as part of research studying C dynamics in re-established wetlands. Flooding rapidly reduced gaseous C losses, and radiocarbon data showed that this, in part, was due to reduced oxidation of "old" C preserved in the organic soils. Both CO2 and CH4 emissions from the water surface increased during the first few growing seasons, concomitant with emergent marsh establishment, and thereafter appeared to stabilize according to plant communities. Areas of emergent marsh vegetation in the shallower wetland had greater net CO2 influx (-485 mg Cm-1 h-1), and lower CH4 emissions (11.5 mg Cm-2 h-1), than in the deeper wetland (-381 and 14.1 mg Cm-2 h-1, respectively). Areas with submerged and floating vegetation in the deeper wetland had CH4 emissions similar to emergent vegetation (11.9 and 12.6 mg Cm-2 h-1, respectively), despite lower net CO2 influx (-102 gC m-2 h-1). Measurements of plant moderated net CO2 influx and CH4 efflux indicated greatest potential reduction of greenhouse gases in the more shallowly flooded wetland.

  14. Vegetative Ecological Characteristics of Restored Reed ( Phragmites australis) Wetlands in the Yellow River Delta, China

    NASA Astrophysics Data System (ADS)

    Wang, Xuehong; Yu, Junbao; Zhou, Di; Dong, Hongfang; Li, Yunzhao; Lin, Qianxin; Guan, Bo; Wang, Yongli

    2012-02-01

    In this study, we compared ecological characteristics of wetland vegetation in a series of restoration projects that were carried out in the wetlands of Yellow River Delta. The investigated characteristics include plant composition structure, species diversity and community similarity in three kinds of Phragmites australis wetlands, i.e. restored P. australis wetlands (R1, R2, R3 and R4: restored in 2002, 2005, 2007 and 2009, respectively), natural P. australis wetland (N) and degraded P. australis wetland (D) to assess the process of wetlands restoration. The coverage of the R1 was 99%, which was similar to natural wetland. Among all studied wetlands, the highest and lowest stem density was observed in R1 and R2, respectively, Plant height and stem diameter show the same trend as N > R2 > R1 > R3 > D > R4. Species diversity of restored P. australis wetlands became closed to natural wetland. Both species richness and Shannon-Wiener index had similar tendency: increased first and then decreased with restored time. The highest species richness and species diversity were observed in R2, while the lowest values of those parameters were found in natural P. australis wetland. Similarity indexes between restored wetlands and natural wetland increased with the restoration time, but they were still less than 50%. The results indicate that the vegetation of P. australis wetlands has experienced a great improvement after several years' restoration, and it is feasible to restored degraded P. australis wetlands by pouring fresh water into those wetlands in the Yellow River Delta. However, it is notable that costal degraded P. australis wetland in this region may take years to decades to reach the status of natural wetland.

  15. Wetland Vegetation Monitoring within Barataria Basin, Louisiana Following Exposure to Oil

    NASA Astrophysics Data System (ADS)

    Steyer, G.; Piazza, S.; Kokaly, R. F.; Patton, B.; Heckman, D.

    2011-12-01

    Following the Deepwater Horizon explosion and subsequent oil spill in April 2010 coastal wetlands in Louisiana were directly oiled, exposing vegetation and marsh soils to petroleum hydrocarbons. Oiling was observed at the marsh/water interface as well as within coastal marshes. The physical and chemical effects of oil spills can have both short and long term effects on wetland vegetation. These effects can include reductions in primary productivity and direct plant mortality. Even in the absence of this oiling event, the coastal landscape of Louisiana experiences high rates of land loss resulting from natural and anthropogenic causes. This additional stress has the potential to further reduce the extent and health of coastal marshes in this fragile ecosystem. We conducted a field study to document the impact of oiling on above and belowground vegetation biomass, plant species composition, and vegetation cover at sites within Barataria Basin, Louisiana. Six sampling sites were established, three within obviously oiled marshes and three where oiling was not readily apparent. Four sampling events occurred between October 2010 and October 2011. The preliminary results of the field study will be presented along with how these data helped validate remotely sensed data observations (AVIRIS) and calibrate ground reflectance in oiled and non-oiled marshes.

  16. Waving Vegetation Facilitates Gas Transfer in Wetland Surface Water

    NASA Astrophysics Data System (ADS)

    Foster, M. R.; Variano, E. A.

    2014-12-01

    Wind-driven movement of flexible vegetation has been an overlooked mechanism in wetland gas models. To understand the magnitude of this effect, a laboratory experiment was conducted. An array of plastic tubes, representing vegetation, was mechanically forced at a range of frequencies and amplitudes matching those observed in the field. Starting from deoxygenated water, we measured dissolved oxygen at mid-depth in the water column using a YSI ProODO as the water re-equilibrated with the atmosphere. From this DO timeseries, we calculated the gas transfer velocity, k, using the thin film gas transport model. This measurement of k was independent of the water-wall interactions, which can be significant in laboratory-scale tanks. Our experiments have shown that the movement of vegetation stirs the water column and thus contributes to the transfer of dissolved gases across the air-water interface. Increased transfer was observed with movements of higher frequency and amplitude. To estimate the occurrence of this phenomena in natural systems, data (e.g. velocity profiles) from a long-term monitoring project in the Florida Everglades will be analyzed. The results can help improve current gas budgets and predict biogeochemical processes.

  17. Inundation, Wetland Vegetation and Biogeochemical Processes in the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Melack, J. M.; Hess, L. L.; Hamilton, S. K.; Richey, J. E.; Novo, E. M.

    2001-12-01

    Remote sensing of the Amazon basin with passive and active microwave techniques were applied to determine the temporally varying extent of inundation and associated vegetation, and used in conjunction with field measurements to calculate regional rates of carbon dioxide emission from wetlands to the atmosphere. Monthly inundation areas were derived from analysis of the 37-GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer (1979 to 1987) for the mainstem Amazon floodplain in Brazil, the Llanos de Moxos (Beni and Mamore rivers) in Bolivia, the Bananal Island (Araguaia River) and Roraima savannas. Maximum areas subject to inundation, including permanent open waters in rivers and lakes, were as follows (in km2): mainstem Amazon 97,400; Moxos 92,000; Bananal 58,500, and Roraima 16,500. Data from the Japanese Earth Resources Satellite-1, L-band synthetic aperture radar were used to determine inundation and wetland vegetation for a quadrat in the central Amazon basin (0o N to 8o S, 72o W to 54o W) at high water (May-June 1996) and low water (October 1995). Flooded area of rivers and floodplains (> 100 m in width) ranged from 79,000 km2 to 290,000 km2. When combined with estimates of inundation associated with streams not detected by the radar, a maximum area of 350,000 km2 (or 20% of the quadrat) was flooded. Combining the areal extent of flooding and measurements of free dissolved CO2 with an evasion model leads to outgassing of CO2 from inundated surfaces to the atmosphere in the central Amazon of 1.1 plus or minus 0.2 MgC ha-1 y-1. Extrapolated over the whole basin, the flux is 10 times the fluvial export of organic carbon to the ocean.

  18. Microbial and vegetative changes associated with development of a constructed wetland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wetlands may be constructed to provide several ecosystem functions. A constructed wetland receiving agricultural runoff water was observed prior to, and for more than two years after, establishment. The excavated portion of this wetland was compared to an undisturbed, upland area and to an adjacent...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. DEVELOPING A WETLAND MONITORING AND ASSESSMENT PROGRAM; BIOLOGICAL ASSESSMENT CRITERIA FOR VEGETATION

    EPA Science Inventory

    The Montana Natural Heritage Program will sample and evaluate riverine and depressional wetlands in the Middle Milk watershed in the Great Plains ecoregion. We will sample wetlands across a human disturbance gradient and collect data on vegetation structure and composition and e...

  1. Tidal saline wetland regeneration of sentinel vegetation types in the Northern Gulf of Mexico: An overview

    USGS Publications Warehouse

    Jones, Scott F; Stagg, Camille L.; Krauss, Ken W.; Hester, Mark W.

    2016-01-01

    Tidal saline wetlands in the Northern Gulf of Mexico (NGoM) are dynamic and frequently disturbed systems that provide myriad ecosystem services. For these services to be sustained, dominant macrophytes must continuously recolonize and establish after disturbance. Macrophytes accomplish this regeneration through combinations of vegetative propagation and sexual reproduction, the relative importance of which varies by species. Concurrently, tidal saline wetland systems experience both anthropogenic and natural hydrologic alterations, such as levee construction, sea-level rise, storm impacts, and restoration activities. These hydrologic alterations can affect the success of plant regeneration, leading to large-scale, variable changes in ecosystem structure and function. This review describes the specific regeneration requirements of four dominant coastal wetland macrophytes along the NGoM (Spartina alterniflora, Avicennia germinans, Juncus roemerianus, and Batis maritima) and compares them with current hydrologic alterations to provide insights into potential future changes in dominant ecosystem structure and function and to highlight knowledge gaps in the current literature that need to be addressed.

  2. Tidal saline wetland regeneration of sentinel vegetation types in the Northern Gulf of Mexico: An overview

    NASA Astrophysics Data System (ADS)

    Jones, Scott F.; Stagg, Camille L.; Krauss, Ken W.; Hester, Mark W.

    2016-06-01

    Tidal saline wetlands in the Northern Gulf of Mexico (NGoM) are dynamic and frequently disturbed systems that provide myriad ecosystem services. For these services to be sustained, dominant macrophytes must continuously recolonize and establish after disturbance. Macrophytes accomplish this regeneration through combinations of vegetative propagation and sexual reproduction, the relative importance of which varies by species. Concurrently, tidal saline wetland systems experience both anthropogenic and natural hydrologic alterations, such as levee construction, sea-level rise, storm impacts, and restoration activities. These hydrologic alterations can affect the success of plant regeneration, leading to large-scale, variable changes in ecosystem structure and function. This review describes the specific regeneration requirements of four dominant coastal wetland macrophytes along the NGoM (Spartina alterniflora, Avicennia germinans, Juncus roemerianus, and Batis maritima) and compares them with current hydrologic alterations to provide insights into potential future changes in dominant ecosystem structure and function and to highlight knowledge gaps in the current literature that need to be addressed.

  3. 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.

  4. Impact of Multiple Environmental Stresses on Wetland Vegetation Dynamics

    NASA Astrophysics Data System (ADS)

    Muneepeerakul, C. P.; Tamea, S.; Muneepeerakul, R.; Miralles-Wilhelm, F. R.; Rinaldo, A.; Rodriguez-Iturbe, I.

    2009-12-01

    This research quantifies the impacts of climate change on the dynamics of wetland vegetation under the effect of multiple stresses, such as drought, water-logging, shade and nutrients. The effects of these stresses are investigated through a mechanistic model that captures the co-evolving nature between marsh emergent plant species and their resources (water, nitrogen, light, and oxygen). The model explicitly considers the feedback mechanisms between vegetation, light and nitrogen dynamics as well as the specific dynamics of plant leaves, rhizomes, and roots. Each plant species is characterized by three independent traits, namely leaf nitrogen (N) content, specific leaf area, and allometric carbon (C) allocation to rhizome storage, which govern the ability to gain and maintain resources as well as to survive in a particular multi-stressed environment. The modeling of plant growth incorporates C and N into the construction of leaves and roots, whose amount of new biomass is determined by the dynamic plant allocation scheme. Nitrogen is internally recycled between pools of plants, litter, humus, microbes, and mineral N. The N dynamics are modeled using a parallel scheme, with the major modifications being the calculation of the aerobic and anoxic periods and the incorporation of the anaerobic processes. A simple hydrologic model with stochastic rainfall is used to describe the water level dynamics and the soil moisture profile. Soil water balance is evaluated at the daily time scale and includes rainfall, evapotranspiration and lateral flow to/from an external water body, with evapotranspiration loss equal to the potential value, governed by the daily average condition of atmospheric water demand. The resulting feedback dynamics arising from the coupled system of plant-soil-microbe are studied in details and species’ fitnesses in the 3-D trait space are compared across various rainfall patterns with different mean and fluctuations. The model results are then

  5. Promoting species establishment in a phragmites-dominated great lakes coastal wetland

    USGS Publications Warehouse

    Carlson, M.L.; Kowalski, K.P.; Wilcox, D.A.

    2009-01-01

    This study examined efforts to promote species establishment and maintain diversity in a Phragmites-dominated wetland where primary control measures were underway. A treatment experiment was performed at Crane Creek, a drowned-river-mouth wetland in Ottawa National Wildlife Refuge along the shore of western Lake Erie. Following initial aerial spraying of Phragmites with glyphosate, this study tested combinations of cutting, raking, and additional hand spraying of Phragmites with glyphosate as methods to promote growth of other wetland species and increase plant diversity. Percent-cover vegetation data were collected in permanent plots before and after treatments, and follow-up sampling was performed the following year. Increased species richness, species emergence, and relative dominance of non-Phragmites taxa were used as measures of treatment success. We also examined treatment effects on Phragmites cover. Dimensionality of seedbank and soil properties was reduced using principal component analysis. With the exception of nitrogen, soil nutrients affected species establishment, non-Phragmites taxa dominance, and Phragmites cover. A more viable seedbank led to greater species emergence. Treatments had differential effects on diversity depending on elevation and resulting degree of hydrologic inundation. Whereas raking to remove dead Phragmites biomass was central to promoting species establishment in dry areas, spraying had a greater impact in continually inundated areas. For treatment success across elevations into the year following treatments, spraying in combination with cutting and raking had the greatest effect. The results of this study suggest that secondary treatments can produce a short-term benefit to the plant community in areas treated for Phragmites.

  6. Statistical classification of vegetation and water depths in montane wetlands

    USGS Publications Warehouse

    Sharp, Julia L.; Sodja, Richard S.; Greenwood, Mark; Rosenberry, Donald O.; Warren, Jeffrey M.

    2013-01-01

    Relationships between water depths and density of submergent vegetation were studied in montane wetlands using statistical techniques based on clustering and an extension of regression trees. Sago pondweed (Stuckenia pectinata) was associated with lower average water depths than water milfoil (Myriophyllum sibiricum). We detected a nonlinear relationship when average water depths were used to predict percent cover in S. pectinata, with depths of 30–40 cm, producing the highest predicted average percent cover of S. pectinata; higher and lower depths resulted in lower percent cover predictions. For M. sibiricum, higher water depths were monotonically associated with higher average percent cover. To foster more S. pectinata and less M. sibiricum, managers might employ water control structures to reduce water depths below 1 m, using both temporary drawdowns and average depths of 30–40 cm. Other species responded less markedly to water depth variation. Should decreased water depths become more common, these results suggest an increase in S. pectinata and a decrease in M. sibiricum.

  7. The flood pulse as the underlying driver of vegetation in the largest wetland and fishery of the Mekong Basin.

    PubMed

    Arias, Mauricio E; Cochrane, Thomas A; Norton, David; Killeen, Timothy J; Khon, Puthea

    2013-11-01

    The Tonle Sap is the largest wetland in Southeast Asia and one of the world's most productive inland fisheries. The Mekong River inundates the Tonle Sap every year, shaping a mosaic of natural and agricultural habitats. Ongoing hydropower development, however, will dampen the flood pulse that maintains the Tonle Sap. This study established the current underlying relationship among hydrology, vegetation, and human use. We found that vegetation is strongly influenced by flood duration; however, this relationship was heavily distorted by fire, grazing, and rice cultivation. The expected flood pulse alteration will result in higher water levels during the dry season, permanently inundating existing forests. The reduction of the maximum flood extent will facilitate agricultural expansion into natural habitats. This study is the most comprehensive field survey of the Tonle Sap to date, and it provides fundamental knowledge needed to understand the underlying processes that maintain this important wetland. PMID:23877417

  8. Influence of hummocks and emergent vegetation on hydraulic performance in a surface flow wastewater treatment wetland

    USGS Publications Warehouse

    Keefe, Steffanie H.; Daniels, Joan S.; Runkel, Robert L.; Wass, Roland D.; Stiles, Eric A.; Barber, Larry B.

    2010-01-01

    A series of tracer experiments were conducted biannually at the start and end of the vegetation growing season in a surface flow wastewater treatment wetland located near Phoenix, AZ. Tracer experiments were conducted prior to and following reconfiguration and replanting of a 1.2 ha treatment wetland from its original design of alternating shallow and deep zones to incorporate hummocks (shallow planting beds situated perpendicular to flow). Tracer test data were analyzed using analysis of moments and the one-dimensional transport with inflow and storage numerical model to evaluate the effects of the seasonal vegetation growth cycle and hummocks on solute transport. Following reconfiguration, vegetation coverage was relatively small, and minor changes in spatial distribution influenced wetland hydraulics. During start-up conditions, the wetland underwent an acclimation period characterized by small vegetation coverage and large transport cross-sectional areas. At the start of the growing season, new growth of emergent vegetation enhanced hydraulic performance. At the end of the growing season, senescing vegetation created short-circuiting. Wetland hydrodynamics were associated with high volumetric efficiencies and velocity heterogeneities. The hummock design resulted in breakthrough curves characterized by multiple secondary tracer peaks indicative of varied flow paths created by bottom topography.

  9. Influence of hummocks and emergent vegetation on hydraulic performance in a surface flow wastewater treatment wetland

    NASA Astrophysics Data System (ADS)

    Keefe, Steffanie H.; Daniels, Joan S. (Thullen); Runkel, Robert L.; Wass, Roland D.; Stiles, Eric A.; Barber, Larry B.

    2010-11-01

    A series of tracer experiments were conducted biannually at the start and end of the vegetation growing season in a surface flow wastewater treatment wetland located near Phoenix, AZ. Tracer experiments were conducted prior to and following reconfiguration and replanting of a 1.2 ha treatment wetland from its original design of alternating shallow and deep zones to incorporate hummocks (shallow planting beds situated perpendicular to flow). Tracer test data were analyzed using analysis of moments and the one-dimensional transport with inflow and storage numerical model to evaluate the effects of the seasonal vegetation growth cycle and hummocks on solute transport. Following reconfiguration, vegetation coverage was relatively small, and minor changes in spatial distribution influenced wetland hydraulics. During start-up conditions, the wetland underwent an acclimation period characterized by small vegetation coverage and large transport cross-sectional areas. At the start of the growing season, new growth of emergent vegetation enhanced hydraulic performance. At the end of the growing season, senescing vegetation created short-circuiting. Wetland hydrodynamics were associated with high volumetric efficiencies and velocity heterogeneities. The hummock design resulted in breakthrough curves characterized by multiple secondary tracer peaks indicative of varied flow paths created by bottom topography.

  10. 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.

  11. ASSESSING THE IMPACTS OF AN INCREASE IN WATER LEVEL ON WETLAND VEGETATION

    EPA Science Inventory

    Three different approaches for assessing the impact of a permanent increase in water level on wetland vegetation were studied using a long-term, controlled, and replicated experiment. hese approaches were (1) digitized vegetation maps derived from aerial photographs; (2) vegetati...

  12. Role of vegetation in a constructed wetland on nutrient-pesticide mixture toxicity of Hyalella azteca

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The toxicity of a nutrient-pesticide mixture in non-vegetated and vegetated sections of a constructed wetland (60 X 30 X 0.3 m) was assessed using Hyalella azteca 48 h aqueous whole effluent toxicity bioassays. Both sections were amended with a mixture of sodium nitrate, triple super phosphate, dia...

  13. Aircraft MSS data registration and vegetation classification of wetland change detection

    USGS Publications Warehouse

    Christensen, E.J.; Jensen, J.R.; Ramsey, Elijah W., III; Mackey, H.E., Jr.

    1988-01-01

    Portions of the Savannah River floodplain swamp were evaluated for vegetation change using high resolution (5a??6 m) aircraft multispectral scanner (MSS) data. Image distortion from aircraft movement prevented precise image-to-image registration in some areas. However, when small scenes were used (200-250 ha), a first-order linear transformation provided registration accuracies of less than or equal to one pixel. A larger area was registered using a piecewise linear method. Five major wetland classes were identified and evaluated for change. Phenological differences and the variable distribution of vegetation limited wetland type discrimination. Using unsupervised methods and ground-collected vegetation data, overall classification accuracies ranged from 84 per cent to 87 per cent for each scene. Results suggest that high-resolution aircraft MSS data can be precisely registered, if small areas are used, and that wetland vegetation change can be accurately detected and monitored.

  14. Transfer of tracers and pesticides in lab scale wetland systems: the role of vegetation

    NASA Astrophysics Data System (ADS)

    Durst, R.; Imfeld, G.; Lange, J.

    2012-04-01

    Surface wetlands can collect contaminated runoff from urban or agricultural catchments and have intrinsic physical, chemical and biological retention and removal processes useful for mitigating contaminants, including pesticides, and thus limiting the contamination of aquatic ecosystems. Yet little is known about the transfer of pesticides between wetlands collecting pesticides runoff and groundwater, and the subsequent threat of groundwater contamination. In particular, the influence of wetland vegetation and related processes during pesticide transfer is largely unknown. Here we evaluate the transfer of the widely used herbicide Isoproturon (IPU) and the fungicide Metalaxyl (MTX) with that of Uranine (UR) and Sulphorhodamine (SRB) in a vegetated and a non-vegetated lab-scale wetland. UR and SRB had successfully served as a reference for pesticides in surface wetlands. We filled two 65 cm long and 15 cm diameter borosilicate columns with sediment cores from a wetland, one without and one with vegetation (Phragmites australis, Cav.). When a constant flow-through rate of 0.33 ml min-1 was reached, tracers and pesticides were injected simultaneously and continuously. The hydrological mass balance and tracer concentrations were measured daily at the outlet of the lab-scale wetland. Samples for pesticides and hydrochemical analyses were collected biweekly. The lab-scale wetlands were covered to limit evaporation and light decay of injected compounds. The reactive transfer of compounds in the vegetated and non-vegetated lab-scale wetland was compared based on breakthrough curves (BTC's) and model parameters of the lumped parameter model CXTFIT. The hydrologic balance revealed that the intensity of transpiration and hence plant activity in the lab-scale wetlands progressively decreased and then apparently ceased after about eight days following continuous pesticide injection. In this first phase, no significant difference in the hydrologic balances could be observed

  15. 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.

  16. Presence of indicator plant species as a predictor of wetland vegetation integrity

    USGS Publications Warehouse

    Stapanian, Martin A.; Adams, Jean V.; Gara, Brian

    2013-01-01

    We fit regression and classification tree models to vegetation data collected from Ohio (USA) wetlands to determine (1) which species best predict Ohio vegetation index of biotic integrity (OVIBI) score and (2) which species best predict high-quality wetlands (OVIBI score >75). The simplest regression tree model predicted OVIBI score based on the occurrence of three plant species: skunk-cabbage (Symplocarpus foetidus), cinnamon fern (Osmunda cinnamomea), and swamp rose (Rosa palustris). The lowest OVIBI scores were best predicted by the absence of the selected plant species rather than by the presence of other species. The simplest classification tree model predicted high-quality wetlands based on the occurrence of two plant species: skunk-cabbage and marsh-fern (Thelypteris palustris). The overall misclassification rate from this tree was 13 %. Again, low-quality wetlands were better predicted than high-quality wetlands by the absence of selected species rather than the presence of other species using the classification tree model. Our results suggest that a species’ wetland status classification and coefficient of conservatism are of little use in predicting wetland quality. A simple, statistically derived species checklist such as the one created in this study could be used by field biologists to quickly and efficiently identify wetland sites likely to be regulated as high-quality, and requiring more intensive field assessments. Alternatively, it can be used for advanced determinations of low-quality wetlands. Agencies can save considerable money by screening wetlands for the presence/absence of such “indicator” species before issuing permits.

  17. Poyang Lake wetland vegetation biomass inversion using polarimetric RADARSAT-2 synthetic aperture radar data

    NASA Astrophysics Data System (ADS)

    Shen, Guozhuang; Liao, Jingjuan; Guo, Huadong; Liu, Ju

    2015-01-01

    Poyang Lake is the largest freshwater lake in China and one of the most important wetlands in the world. Vegetation, an important component of wetland ecosystems, is one of the main sources of the carbon in the atmosphere. Biomass can quantify the contribution of wetland vegetation to carbon sinks and carbon sources. Synthetic aperture radar (SAR), which can operate in all day and weather conditions and penetrate vegetation to some extent, can be used to retrieve information about vegetation structure and the aboveground biomass. In this study, RADARSAT-2 polarimetric SAR data were used to retrieve aboveground vegetation biomass in the Poyang Lake wetland. Based on the canopy backscatter model, the vegetation backscatter characteristics in the C-band were studied, and a good relation between simulated backscatter and backscatter in the RADARSAT-2 imagery was achieved. Using the backscatter model, pairs of training data were built and used to train the back propagation artificial neural network. The biomass was retrieved using this ANN and compared with the field survey results. The root-mean-square error in the biomass estimation was 45.57 g/m2. This shows that the combination of the model and polarimetric decomposition components can efficiently improve the inversion precision.

  18. Impacts of Land Use on Wetland Vegetation in the Eastern United States: Timing and Scale

    NASA Astrophysics Data System (ADS)

    Bernhardt, C. E.; Willard, D. A.; Townsend, P.; Brown, R.

    2004-12-01

    The timing and scale of vegetation change are dependent on the resilience of the ecosystem to land use change that alters hydrologic response and sediment transport. Using palynological methods, we examine the impacts of land use change in 2 distinct ecosystems (the subtropical Florida Everglades and the temperate Roanoke River floodplain) in the Eastern United States. Twentieth century water management strategies have modified the hydrology within the Florida Everglades resulting in varying degrees of vegetation changes depending on community type and location within the greater Everglades ecosystem. Analysis of pollen assemblages from herbaceous wetland communities such as sawgrass ridges, open water sloughs, and marl prairies, show rapid vegetation change in response to both increases and decreases in hydrology. However, evaluations of these wetland environments over longer time periods (centuries to millennia) and through natural alterations to hydroperiod (like Medieval Warm Period) demonstrated the ability of the vegetation to recover within a few decades. Tree-island communities, composed of flood-intolerant, woody vegetation, are largely resistant to decreases in hydroperiod. They are, however, less tolerant to sustained increases (greater than 5 years) in water levels, with no seasonal drying, resulting in long-term degradation. Tree-island pollen assemblages indicate rapid changes in vegetation composition when subjected to prolonged hydroperiod (essentially drowning the tree islands). Pollen assemblages from the Roanoke River floodplain provide a perspective on the impacts of colonial land clearance, altered sedimentation, and changes in flooding regimes on forested wetland vegetation. After land clearance, organic to mineral sediments covered organic floodplain soils. Palynological evidence suggests a change towards less flood tolerant communities in areas of greatest sedimentation. These results demonstrate the rapid response of wetland plant

  19. The Effect of Manning's Roughness Calibration on Flow and Sediment transport in Wetlands: Vegetation Drag Approach

    NASA Astrophysics Data System (ADS)

    Mahmoudi, M.; Nalesso, M.; Garcia, R. F.; Miralles-Wilhelm, F.

    2013-05-01

    Wetland hydrology is one of the most complex and important factors that dictate landscape patterning in wetlands. Understanding factors that affect wetland hydrology are very important. Subtropical wetlands with low gradient, such as The Everglades in South Florida, are generally covered by various type of vegetation with area of highly vegetated and area with almost no plant density. Ridge and slough are one of the several major habitat types in the Everglades that are characterized by highly vegetated ridge with higher elevation and channelized slough with less dense vegetation. They are originally consisted of a peat - based systems of dense sawgrass ridges (Cladium jamaicense) interspersed with adjacent and relatively open sloughs. Because of vegetation dynamics, the hydrology is highly depends on vegetation drag force. Kadlec (1990) and Shi et al., 1995 stated that additional drag exerted by plants reduces the mean flow velocity and depth within the vegetated regions. Vegetation flexibility (flexible grasslike vs. rigid or less flexible bushes or trees) may affect flow resistance. In addition, total or partially submerged vegetation may also change the flow velocity. Most of vegetation in wetlands are partially submerged and therefore, flow resistance can be related to bed shear stress (Yen, 2002; Wu et al., 1999). The new modified Manning's coefficient expression estimates roughness value based on vegetation type, length, density, and vegetation being submerged/unsubmerged (Wu et al., 1999). This modification was applied to flow simulation in the study area at Loxahatchee Impoundment Landscape Assessment (LILA). Loxahatchee Impoundment Landscape Assessment (LILA) is living laboratory of The Everglades and is located at Boynton Beach, Florida and consists of 80 acres land divided into four macrocosms of 200 m × 400 m. Each macrocosm includes one ridge one slough and two tree islands. Two of the cells are non flowing cells and the others are constant flowing

  20. Efficiency of Constructed Wetland Vegetated with Cyperus alternifolius Applied for Municipal Wastewater Treatment

    PubMed Central

    Ebrahimi, Asghar; Taheri, Ensiyeh; Ehrampoush, Mohammad Hassan; Nasiri, Sara; Jalali, Fatemeh; Soltani, Rahele; Fatehizadeh, Ali

    2013-01-01

    The treatment of municipal wastewater from Yazd city (center of Iran) by constructed wetland vegetated with Cyperus alternifolius was assessed. Two identical wetlands with a total working volume of 60 L and 10 cm sandy layer at the bottom were used. First wetland (W1) was control and had no Cyperus alternifolius plant. Second wetland (W2) had 100 Cyperus alternifolius shrubs with 40 cm height. Influent wastewater was provided from Yazd's septic tanks effluents and after a 4-day retention time in wetlands, reactors effluent was sampled for parameters analysis. Results show that chemical oxygen demand (COD), NO3−–N, NH4+–N, and PO4−3–P in W1 were reduced to 72%, 88%, 32%, and 0.8%, and in W2, these parameters were removed in values of 83%, 81%, 47%, and 10%, respectively. In both wetlands, the highest and lowest removal efficiencies were related to COD and phosphorus, respectively. Also, the removed phosphorus can be released to stream when the soil saturated or influent phosphorus decreased and when the plant died. After a 4-day-retention time, the W2 wetland showed a statistically significantly lower COD and NH4+–N in comparison with W2 wetland. PMID:24027589

  1. The use of discharge perturbations to understand in situ vegetation resistance in wetlands

    NASA Astrophysics Data System (ADS)

    Lal, A. M. Wasantha; Moustafa, M. Zaki; Wilcox, Walter M.

    2015-04-01

    The ability to better quantify resistance to water flow exerted by vegetation is receiving increased attention due to ongoing worldwide efforts to restore natural vegetation communities in the wetlands and use of vegetation for environmental benefits in streams and wetlands. In south Florida, vegetation resistance affects discharge through shallow wetlands of the Everglades and projects under way in the system to restore remaining natural systems. A more detailed knowledge of the flow dynamics in these wetlands is required to improve modeling of these systems that supports restoration and management efforts. The goal of this investigation is to understand the flow dynamics and the vegetation resistance within a 3 km by 7 km area in the Everglades referred to as STA-3/4 Cell 3A. Methods are developed to demonstrate the use of analytical solutions of partial differential equations (PDEs) and inverse methods to obtain bulk and spatially varying resistance parameters. To achieve this goal, a field test was conducted using sinusoidal discharge disturbances capable of creating water waves in the storm water treatment area (STAs). The discharges, wave speeds, and the wave attenuation rates from the test are used to develop graphical and empirical functions expressing discharge in terms of water depth and energy slope. The empirical functions developed are power law type, and different functions are developed for different depths. The results show that the Manning's equation is not applicable for wetlands with thick emergent vegetation, as well as the difficulty of applying a single power law-type expression for vegetation resistance over a wide range of depths and energy slopes without errors. This is partly due to the existence of multiple flow regimes and different power exponents over depth and energy slopes in these regimes. Results show that the flow regime at low depths is similar to porous media flow, and the flow regime at higher depths is more turbulent.

  2. Analysis on vegetation changes of Maqu alpine wetlands in the Yellow River source region

    NASA Astrophysics Data System (ADS)

    Chu, Lin; Huang, Chong; Liu, Gaohuan; Liu, Qingsheng; Zhao, Jun

    2014-11-01

    The Maqu alpine wetlands have irreplaceable function in maintaining ecological balance and conserving biodiversity to the upriver regions of the Yellow River. In last 30 years, Global warming causes significant changes in vegetation. However, the Maqu alpine wetland is undergoing a degradation caused by warming and drying climate. Aim of this study is to investigate the vegetation changes for a better understanding the consequence of climate variations to the wetland degradation. Based on the Landsat TM images of 2000 and 2010, the landscape pattern changes were analyzed by classification statistics, dynamic transfer matrix and landscape pattern indices. Based on the MOD11A2 and MOD13A2 data from 2000 to 2010, NDVI and land surface temperature (LST) dataset were extracted. NDVI time-series data processed with S-G filtering method was used to find temporal and spatial variation characteristics, and linear trend was analyzed by ordinary least squares regression method. NDVI and LST were used to construct Ts-NDVI feature space, and then TVDI was obtained to explore changes of soil moisture. Relationship between climate variations and wetland degradation were found by ordinary least squares regression method. Results indicated that both wetland area and landscape heterogeneity decreased. Annual NDVI presented fluctuated decreasing trend and there was strong spatial heterogeneity in patterns of NDVI change. Annual TVDI proved to have an increasing trend which showed the drought gradually intensified. "Warming and drought" climate appear to be critical factors contributing to wetland degradation. Precipitation has a stronger correlation rather than temperature.

  3. Mapping swamp timothy (Cripsis schenoides) seed productivity using spectral values and vegetation indices in managed wetlands

    SciTech Connect

    Rahilly, P.J.A.; Li, D.; Guo, Q.; Zhu, J.; Ortega, R.; Quinn, N.W.T.; Harmon, T.C.

    2010-01-15

    This work examines the potential to predict the seed productivity of a key wetland plant species using spectral reflectance values and spectral vegetation indices. Specifically, the seed productivity of swamp timothy (Cripsis schenoides) was investigated in two wetland ponds, managed for waterfowl habitat, in California's San Joaquin Valley. Spectral reflectance values were obtained and associated spectral vegetation indices (SVI) calculated from two sets of high resolution aerial images (May 11, 2006 and June 9, 2006) and were compared to the collected vegetation data. Vegetation data were collected and analyzed from 156 plots for total aboveground biomass, total aboveground swamp timothy biomass, and total swamp timothy seed biomass. The SVI investigated included the Simple Ratio (SR), Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI), Transformed Soil Adjusted Vegetation Index (TSAVI), Modified Soil Adjusted Vegetation Index (MSAVI), and Global Environment Monitoring Index (GEMI). We evaluated the correlation of the various SVI with in situ vegetation measurements for linear, quadratic, exponential and power functions. In all cases, the June image provided better predictive capacity relative to May, a result that underscores the importance of timing imagery to coincide with more favorable vegetation maturity. The north pond with the June image using SR and the exponential function (R{sup 2}=0.603) proved to be the best predictor of swamp timothy seed productivity. The June image for the south pond was less predictive, with TSAVI and the exponential function providing the best correlation (R{sup 2}=0.448). This result was attributed to insufficient vegetal cover in the south pond (or a higher percentage of bare soil) due to poor drainage conditions which resulted in a delay in swamp timothy germination. The results of this work suggest that spectral reflectance can be used to estimate seed productivity in managed seasonal

  4. Diazinon mitigation in constructed wetlands: influence of vegetation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In intensively cultivated areas, agriculture is a significant source of pesticides associated with storm runoff. When these pollutants enter aquatic receiving waters, they have potential to damage nearby aquatic ecosystems. Constructed wetlands are a best management practice (BMP) designed to help...

  5. Biomass estimation of wetland vegetation in Poyang Lake area using ENVISAT advanced synthetic aperture radar data

    NASA Astrophysics Data System (ADS)

    Liao, Jingjuan; Shen, Guozhuang; Dong, Lei

    2013-01-01

    Biomass estimation of wetlands plays a role in understanding dynamic changes of the wetland ecosystem. Poyang Lake is the largest freshwater lake in China, with an area of about 3000 km2. The lake's wetland ecosystem has a significant impact on leveraging China's environmental change. Synthetic aperture radar (SAR) data are a good choice for biomass estimation during rainy and dry seasons in this region. In this paper, we discuss the neural network algorithms (NNAs) to retrieve wetland biomass using the alternating-polarization ENVISAT advanced synthetic aperture radar (ASAR) data. Two field measurements were carried out coinciding with the satellite overpasses through the hydrological cycle in April to November. A radiative transfer model of forest canopy, the Michigan Microwave Canopy Scattering (MIMICS) model, was modified to fit to herbaceous wetland ecosystems. With both ASAR and MIMICS simulations as input data, the NNA-estimated biomass was validated with ground-measured data. This study indicates the capability of NNA combined with a modified MIMICS model to retrieve wetland biomass from SAR imagery. Finally, the overall biomass of Poyang Lake wetland vegetation has been estimated. It reached a level of 1.09×109, 1.86×108, and 9.87×108 kg in April, July, and November 2007, respectively.

  6. Experimental removal of wetland emergent vegetation leads to decreased methylmercury production in surface sediment

    USGS Publications Warehouse

    Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark; Krabbenhoft, David P.; Agee, Jennifer L.; Cox, Marisa H.; Heredia-Middleton, Pilar; Coates, Carolyn; Kakouros, Evangelos

    2009-01-01

    We performed plant removal (devegetation) experiments across a suite of ecologically diverse wetland settings (tidal salt marshes, river floodplain, rotational rice fields, and freshwater wetlands with permanent or seasonal flooding) to determine the extent to which the presence (or absence) of actively growing plants influences the activity of the Hg(II)-methylating microbial community and the availability of Hg(II) to those microbes. Vegetated control plots were paired with neighboring devegetated plots in which photosynthetic input was terminated 4–8 months prior to measurements, through clipping aboveground biomass, severing belowground connections, and shading the sediment surface to prevent regrowth. Across all wetlands, devegetation decreased the activity of the Hg(II)-methylating microbial community (kmeth) by 38%, calculated MeHg production potential (MP) rates by 36%, and pore water acetate concentration by 78%. Decreases in MP were associated with decreases in microbial sulfate reduction in salt marsh settings. In freshwater agricultural wetlands, decreases in MP were related to indices of microbial iron reduction. Sediment MeHg concentrations were also significantly lower in devegetated than in vegetated plots in most wetland settings studied. Devegetation effects were correlated with live root density (percent volume) and were most profound in vegetated sites with higher initial pore water acetate concentrations. Densely rooted wetlands had the highest rates of microbial Hg(II)-methylation activity but often the lowest concentrations of bioavailable reactive Hg(II). We conclude that the exudation of labile organic carbon (e.g., acetate) by plants leads to enhanced microbial sulfate and iron reduction activity in the rhizosphere, which results in high rates of microbial Hg(II)-methyation and high MeHg concentrations in wetland sediment.

  7. Experimental removal of wetland emergent vegetation leads to decreased methylmercury production in surface sediment

    USGS Publications Warehouse

    Windham-Myers, L.; Marvin-DiPasquale, M.; Krabbenhoft, D.P.; Agee, J.L.; Cox, M.H.; Heredia-Middleton, P.; Coates, C.; Kakouros, E.

    2009-01-01

    We performed plant removal (devegetation) experiments across a suite of ecologically diverse wetland settings (tidal salt marshes, river floodplain, rotational rice fields, and freshwater wetlands with permanent or seasonal flooding) to determine the extent to which the presence (or absence) of actively growing plants influences the activity of the Hg(II)-methylating microbial community and the availability of Hg(II) to those microbes. Vegetated control plots were paired with neighboring devegetated plots in which photosynthetic input was terminated 4-8 months prior to measurements, through clipping aboveground biomass, severing belowground connections, and shading the sediment surface to prevent regrowth. Across all wetlands, devegetation decreased the activity of the Hg(II)-methylating microbial community (kmeth) by 38%, calculated MeHg production potential (MP) rates by 36%, and pore water acetate concentration by 78%. Decreases in MP were associated with decreases in microbial sulfate reduction in salt marsh settings. In freshwater agricultural wetlands, decreases in MP were related to indices of microbial iron reduction. Sediment MeHg concentrations were also significantly lower in devegetated than in vegetated plots in most wetland settings studied. Devegetation effects were correlated with live root density (percent volume) and were most profound in vegetated sites with higher initial pore water acetate concentrations. Densely rooted wetlands had the highest rates of microbial Hg(II)-methylation activity but often the lowest concentrations of bioavailable reactive Hg(II). We conclude that the exudation of labile organic carbon (e.g., acetate) by plants leads to enhanced microbial sulfate and iron reduction activity in the rhizosphere, which results in high rates of microbial Hg(II)-methyation and high MeHg concentrations in wetland sediment.

  8. Experimental removal of wetland emergent vegetation leads to decreased methylmercury production in surface sediment

    NASA Astrophysics Data System (ADS)

    Windham-Myers, Lisamarie; Marvin-Dipasquale, Mark; Krabbenhoft, David P.; Agee, Jennifer L.; Cox, Marisa H.; Heredia-Middleton, Pilar; Coates, Carolyn; Kakouros, Evangelos

    2009-06-01

    We performed plant removal (devegetation) experiments across a suite of ecologically diverse wetland settings (tidal salt marshes, river floodplain, rotational rice fields, and freshwater wetlands with permanent or seasonal flooding) to determine the extent to which the presence (or absence) of actively growing plants influences the activity of the Hg(II)-methylating microbial community and the availability of Hg(II) to those microbes. Vegetated control plots were paired with neighboring devegetated plots in which photosynthetic input was terminated 4-8 months prior to measurements, through clipping aboveground biomass, severing belowground connections, and shading the sediment surface to prevent regrowth. Across all wetlands, devegetation decreased the activity of the Hg(II)-methylating microbial community (kmeth) by 38%, calculated MeHg production potential (MP) rates by 36%, and pore water acetate concentration by 78%. Decreases in MP were associated with decreases in microbial sulfate reduction in salt marsh settings. In freshwater agricultural wetlands, decreases in MP were related to indices of microbial iron reduction. Sediment MeHg concentrations were also significantly lower in devegetated than in vegetated plots in most wetland settings studied. Devegetation effects were correlated with live root density (percent volume) and were most profound in vegetated sites with higher initial pore water acetate concentrations. Densely rooted wetlands had the highest rates of microbial Hg(II)-methylation activity but often the lowest concentrations of bioavailable reactive Hg(II). We conclude that the exudation of labile organic carbon (e.g., acetate) by plants leads to enhanced microbial sulfate and iron reduction activity in the rhizosphere, which results in high rates of microbial Hg(II)-methyation and high MeHg concentrations in wetland sediment.

  9. Bathymetry and vegetation in isolated marsh and cypress wetlands in the northern Tampa Bay Area, 2000-2004

    USGS Publications Warehouse

    Haag, Kim H.; Lee, Terrie M.; Herndon, Donald C.

    2005-01-01

    Wetland bathymetry and vegetation mapping are two commonly used lines of evidence for assessing the hydrologic and ecologic status of expansive coastal and riverine wetlands. For small isolated freshwater wetlands, however, bathymetric data coupled with vegetation assessments are generally scarce, despite the prevalence of isolated wetlands in many regions of the United States and the recognized importance of topography as a control on inundation patterns and vegetation distribution. In the northern Tampa Bay area of west-central Florida, bathymetry was mapped and vegetation was assessed in five marsh and five cypress wetlands. These 10 isolated wetlands were grouped into three categories based on the effects of ground-water withdrawals from regional municipal well fields: natural (no effect), impaired (drier than natural), and augmented (wetlands with artificially augmented water levels). Delineation of the wetland perimeter was a critical component for estimating wetland-surface area and stored water volume. The wetland perimeter was delineated by the presence of Serenoa repens (the 'palmetto fringe') at 9 of the 10 sites. At the 10th site, where the palmetto fringe was absent, hydric-soils indicators were used to delineate the perimeter. Bathymetric data were collected using one or more techniques, depending on the physical characteristics of each wetland. Wetland stage was measured hourly using continuous stage recorders. Wetland vegetation was assessed semiannually for 2 1/2 years in fixed plots located at three distinct elevations. Vegetation assessments were used to determine the community composition and the relative abundance of obligate, facultative wet, and facultative species at each elevation. Bathymetry maps were generated, and stage-area and stage-volume relations were developed for all 10 wetlands. Bathymetric data sets containing a high density of data points collected at frequent and regular spatial intervals provided the most useful stage

  10. HYDROLOGIC CONSTRAINTS TO THE EFFECTIVENESS OF VEGETATED RIPARIAN BUFFERS AND CONSTRUCTED WETLANDS FOR POLLUTION CONTROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetated riparian buffers and constructed wetlands are among the stream-corridor management systems that can reduce the amount of sediments, nutrients, and biocides entering streams. Hydrologic factors can constrain water-quality benefits of these practices because riparian buffers can only affect...

  11. The effect of floating vegetation on denitrification and greenhouse gas production in wetland mesocosms

    NASA Astrophysics Data System (ADS)

    Jacobs, A. E.; Harrison, J. A.

    2012-12-01

    Anthropogenic intensification of nitrogen (N) loading to aquatic ecosystems is widespread and can lead to the degradation of these systems. Wetlands are important sites for N removal via denitrification, the microbially mediated reduction of reactive nitrate to inert N2 gas, but they can also produce high levels of greenhouse gases. Floating plants play an important role in encouraging denitrification, since they create low oxygen conditions that may favor denitrification. We investigated whether wetland sediments with floating plant cover had higher denitrification and greenhouse gas production rates than wetland sediments without floating plants. Replicate flow-through mesocosms with wetland sediment and water were constructed in a growth chamber to mimic the wetland where the sediment and water were collected. Mesocosm treatments were covered with floating vegetation (duckweed), an opaque tarp, or no cover to determine how cover type affects denitrification and greenhouse gas production and whether biotic or abiotic factors are likely responsible for observed differences. Denitrification and greenhouse gas production rates were calculated by measuring excess N2 gas, methane, and nitrous oxide concentrations in the water column and measuring the gas exchange rates between the water column and the atmosphere. Gas exchange rates were measured using an inert volatile tracer added to the water column and accumulation of gas in the mesocosm headspace. Additional mesocosm experiments were performed to determine how duckweed-dominated wetland systems respond to nitrogen loading and which mechanism for lowering dissolved oxygen concentrations is important in affecting denitrification under floating vegetation. Mesocosms with floating vegetation had lower dissolved oxygen than no cover or tarp-covered mesocosms, which is consistent with field and literature observations. Water flowing out of the mesocosms had statistically lower total nitrogen and nitrate concentrations

  12. Effect of climate fluctuations on long-term vegetation dynamics in Carolina bay wetlands

    USGS Publications Warehouse

    Stroh, C.L.; De Steven, D.; Guntenspergen, G.R.

    2008-01-01

    Carolina bays and similar depression wetlands of the U.S. Southeastern Coastal Plain have hydrologic regimes that are driven primarily by rainfall. Therefore, climate fluctuations such as drought cycles have the potential to shape long-term vegetation dynamics. Models suggest two potential long-term responses to hydrologic fluctuations, either cyclic change maintaining open emergent vegetation, or directional succession toward forest vegetation. In seven Carolina bay wetlands on the Savannah River Site, South Carolina, we assessed hydrologic variation and vegetation response over a 15-year period spanning two drought and reinundation cycles. Changes in pond stage (water depth) were monitored bi-weekly to monthly each year from 1989?2003. Vegetation composition was sampled in three years (1989, 1993, and 2003) and analyzed in relation to changes in hydrologic conditions. Multi-year droughts occurred prior to the 1989 and 2003 sampling years, whereas 1993 coincided with a wet period. Wetland plant species generally maintained dominance after both wet and dry conditions, but the abundances of different plant growth forms and species indicator categories shifted over the 15-year period. Decreased hydroperiods and water depths during droughts led to increased cover of grass, upland, and woody species, particularly at the shallower wetland margins. Conversely, reinundation and longer hydroperiods resulted in expansion of aquatic and emergent species and reduced the cover of flood-intolerant woody and upland species. These semi-permanent Upper Coastal Plain bays generally exhibited cyclic vegetation dynamics in response to climate fluctuation, with wet periods favoring dominance by herbaceous species. Large basin morphology and deep ponding, paired with surrounding upland forest dominated by flood-intolerant pines, were features contributing to persistence of herbaceous vegetation. Drought cycles may promote directional succession to forest in bays that are smaller

  13. Modeling Vegetation Dynamics in Response to Hydrological Changes in a Small Urban Tropical Freshwater Wetland

    NASA Astrophysics Data System (ADS)

    Chui, T. M.; Palanisamy, B.; Mohanadas, H.

    2011-12-01

    Wetlands worldwide face drastic degradation from human-induced changes. A small freshwater wetland located within the dense urbanized island state of Singapore---the Nee Soon Wetland---is no exception. It is the only significant locality in Singapore of peat swamp forest and is home to a wide range of rare and endangered floral and faunal species. Unfortunately, changes in downstream land use and surrounding reservoirs' operations may pose threats to the coupled hydrological and vegetation systems. This study develops and applies coupled hydrological-vegetation models to understand the dynamic relationships between hydrology and vegetation systems, and simulates vegetation responses to hydrological changes in Nee Soon. The models combine a hydrological component with a vegetation component. The hydrological component accounts for both saturated and unsaturated flows, and incorporates evapotranspiration, rainfall infiltration and recharge from streams and reservoirs. The vegetation component is described by Lokta-Volterra equations that are tailored for plant growth, to simulate the vegetation dynamics of up to three species that thrive in different flooding conditions. Important findings include: (1) groundwater levels within Nee Soon are not highly sensitive to the operating levels of the surrounding reservoirs. However, (2) downstream drainage results in a localized zone of influence with significant adverse impacts, especially on the less flood-tolerant species. In addition, (3) the severely impacted less flood-tolerant species is unable to recover even when previous hydrological conditions are restored, unless the downstream drainage duration is reduced, or the plant characteristics such as maximum assimilation rates or competitiveness are increased. Finally, (4) hydrological conditions and species competitiveness supersede any other plant growth characteristics in determining the stable coexistence of different species. The developed models and modeling

  14. Role of vegetation in a constructed wetland on nutrient-pesticide mixture toxicity to Hyalella azteca.

    PubMed

    Lizotte, Richard E; Moore, Matthew T; Locke, Martin A; Kröger, Robert

    2011-02-01

    The toxicity of a nutrient-pesticide mixture in nonvegetated and vegetated sections of a constructed wetland (882 m² each) was assessed using Hyalella azteca 48-h aqueous whole-effluent toxicity bioassays. Both sections were amended with a mixture of sodium nitrate, triple superphosphate, diazinon, and permethrin simulating storm-event agricultural runoff. Aqueous samples were collected at inflow, middle, and outflow points within each section 5 h, 24 h, 72 h, 7 days, 14 days, and 21 days postamendment. Nutrients and pesticides were detected throughout both wetland sections with concentrations longitudinally decreasing more in vegetated than nonvegetated section within 24 h. Survival effluent dilution point estimates-NOECs, LOECs, and LC₅₀s-indicated greatest differences in toxicity between nonvegetated and vegetated sections at 5 h. Associations of nutrient and pesticide concentrations with NOECs indicated that earlier toxicity (5-72 h) was from permethrin and diazinon, whereas later toxicity (7-21 days) was primarily from diazinon. Nutrient-pesticide mixture concentration-response assessment using toxic unit models indicated that H. azteca toxicity was due primarily to the pesticides diazinon and permethrin. Results show that the effects of vegetation versus no vegetation on nutrient-pesticide mixture toxicity are not evident after 5 h and a 21-day retention time is necessary to improve H. azteca survival to ≥90% in constructed wetlands of this size. PMID:20814671

  15. Effects of vegetation manipulation on breeding waterfowl in prairie wetlands--a literature review

    USGS Publications Warehouse

    Kantrud, H.A.

    1986-01-01

    Literature on the effects of fire and grazing on the wetlands used by breeding prairie waterfowl is reviewed. Both dabbling and diving ducks and their broods prefer wetlands with openings in the marsh canopy. Decreased use is commonly associated with decreased habitat heterogeneity caused by tall, robust hydrophytes such as Typha spp. and other species adapted to form monotypes in the absence of disturbance. Nearly all previous studies indicate that reductions in height and density of tall, emergent hydrophytes by fire and grazing (unless very intensive) generally benefit breeding waterfowl. Such benefits are an increase in pair density, probably related to increased interspersion of cover and open water which decreases visibility among conspecific pairs, and improvements in their invertebrate food resources that result from increased habitat heterogeneity. Research needs are great because of the drastic changes that have accrued to prairie wetlands through fire suppression, cultivation, and other factors. The physical and biological environments preferred by species of breeding waterfowl during their seasonal and daily activities should be ascertained from future studies in wetland complexes that exist in the highest state of natural preservation. Long-term burning and grazing experiments should follow on specific vegetatively-degraded wetlands judged to be potentially important breeding areas. Seasonality, frequency, and intensity of treatments should be varied and combined and, in addition to measuring the response of the biotic community, the changes in the physical and chemical environment of the wetlands should be monitored to increase our knowledge of causative factors and possible predictive values.

  16. Interactions between vegetation and hydrology: 1) Forest structure and throughfall 2) Spruce expansion following wetland drying

    NASA Astrophysics Data System (ADS)

    Smeltz, T. Scott

    Chapter 1: We developed a non-linear regression model from first principals to predict the percent of precipitation interception from forest canopies using lidar as a measure of forest structure. To find the best parameters for the model, we measured thoroughfall of rain (n = 21), fresh snow (n = 21), and old snow (n = 26) on plots in the boreal forest of the upper Eklutna Valley, Alaska. We calculated a set of twelve lidar metrics for each plot, and found the combined metric of mean height * cover to be the lidar metric most highly correlated to ln(throughfall) for rain (r = -0.81), fresh snow (r = -0.79), and old snow (r = -0.73). Using mean height * cover in the interception model, we predicted mean interception for rainfall (20% +/- 3%), fresh snow (29% +/- 4%), and old snow (20% +/- 3%) across the vegetated portion of the upper Eklutna Valley. Chapter 2: Climate changes and subsequent landscape-level responses have been documented throughout Alaska. We investigated the expansion of black (Picea mariana) and white spruce (Picea glauca) into open, herbaceous palustrine wetlands on Joint Base Elemendorf-Richardson (JBER) in south-central Alaska. We classified random points in wetlands across JBER using imagery from 1950, 1981, and 2012 to identify the extent and rate of spruce expansion. Additionally, we sampled 75 field plots in wetlands to age spruce trees and survey understory vegetation. We found tree cover in wetlands to have increased substantially from 1950-2012 (44% to 87%) with expansion over time fitting a logistic growth model well. Aged tree cores showed a recruitment pulse beginning the in 1930's and had a cumulative age distribution matching the logistic growth model of tree cover over time. The logistic growth model suggest spruce expansion began slowly in the early 1800's, coincident with the start of the current warming trend in Alaska. Using one representative wetland, we classified points on a 10 m spaced regular grid in 1950, 1981, and 2012 to

  17. Hydrologic, soil, and vegetation gradients in remnant and constructed riparian wetlands in west-central Missouri, 2001-04

    USGS Publications Warehouse

    Heimann, David C.; Mettler-Cherry, Paige A.

    2004-01-01

    not been significantly altered; however, portions of the area have suffered from hydrologic alteration by a drainage ditch that is resulting in the displacement of swamp and marsh species by colonizing shrub and tree species. This area likely will continue to develop into an immature flood plain forest under the current (2004) hydrologic regime. Reforestation plots in constructed wetlands consisted of sampling survival and growth of multiple tree species (Quercus palustris, pin oak; Carya illinoiensis, pecan) established under several production methods and planted at multiple elevations. Comparison of survival between tree species and production types showed no significant differences for all comparisons. Survival was high for both species and all production types, with the highest mortality seen in the mounded root production method (RPM?) Quercus palustris (pin oak, 6.9 percent), while direct seeded Quercus palustris at middle elevation and bare root Quercus palustris seedlings at the low elevation plots had 100 percent survival. Measures of growth (diameter and height) were assessed among species, production types, and elevation by analyzing relative growth. The greatest rate of tree diameter (72.3 percent) and height (65.3 percent) growth was observed for direct seeded Quercus palustris trees planted at a middle elevation site. Natural colonized vegetation data were collected at multiple elevations within an abandoned cropland area of a constructed wetland. The primary measured determining factors in the distribution of herbaceous vegetation in this area were elevation, ponding duration, and soil texture. Richness, evenness, and diversity were all significantly greater in the highest elevation plots as a result of more recent disturbance in this area. While flood frequency and duration define the delivery mechanism for inundation on the flood plain, it is the duration of ponding and amount of 'topographic capture' of these floodwaters in fluvial lan

  18. Vegetation survey of Four Mile Creek wetlands. [Savannah River Plant

    SciTech Connect

    Loehle, C.

    1990-11-01

    A survey of forested wetlands along upper Four Mile Creek was conducted. The region from Road 3 to the creek headwaters was sampled to evaluate the composition of woody and herbaceons plant communities. All sites were found to fall into either the Nyssa sylvatica (Black Gum) -- Persea borbonia (Red Bay) or Nyssa sylvatica -- Acer rubrum (Red Maple) types. These community types are generally species-rich and diverse. Previous studies (Greenwood et al., 1990; Mackey, 1988) demonstrated contaminant stress in areas downslope from the F- and H-Area seepage basins. In the present study there were some indications of contaminant stress. In the wetland near H-Area, shrub basal area, ground cover stratum species richness, and diversity were low. In the area surrounding the F-Area tree kill zone, ground cover stratum cover and shrub basal area were low and ground cover stratum species richness was low. The moderately stressed site at F-Area also showed reduced overstory richness and diversity and reduced ground cover stratum richness. These results could, however, be due to the very high basal area of overstory trees in both stressed F-Area sites that would reduce light availability to understory plants. No threatened or endangered plant species were found in the areas sampled. 40 refs., 4 figs., 8 tabs.

  19. Multitemporal classification of TerraSAR-X data for wetland vegetation mapping

    NASA Astrophysics Data System (ADS)

    Betbeder, Julie; Rapinel, Sébastien; Corpetti, Thomas; Pottier, Eric; Corgne, Samuel; Hubert-Moy, Laurence

    2014-01-01

    This paper is concerned with wetland vegetation mapping using multitemporal synthetic aperture radar imagery. Although wetlands play a key role in controlling flooding and nonpoint source pollution, sequestering carbon and providing an abundance of ecological services, knowledge of the flora and fauna of these environments is patchy, and understanding of their ecological functioning is still insufficient for a reliable functional assessment on areas larger than a few hectares. The aim of this paper is to evaluate multitemporal TerraSAR-X imagery to precisely map the distribution of vegetation formations considering flood duration. A series of six dual-polarization TerraSAR-X images (HH-VV) was acquired in 2012 during dry and wet seasons. One polarimetric parameter, the Shannon entropy (SE), and two intensity parameters (σ° HH and σ° VV), which vary with wetland flooding status and vegetation roughness, were first extracted. These parameters were then classified using support vector machine techniques based on a specific kernel adapted to the comparison of time-series data, K-nearest neighbors, and decision tree (DT) algorithms. The results show that the vegetation formations can be identified very accurately (kappa index=0.85) from the classification of SE temporal profiles derived from the TerraSAR-X images. They also reveal the importance of the use of polarimetric parameters instead of backscattering coefficients alone (HH or VV) or combined (HH and VV).

  20. Drivers and feedbacks in spatial and temporal patterning of hydrology and vegetation in the Everglades wetlands

    NASA Astrophysics Data System (ADS)

    Miralles-Wilhelm, F.; Foti, R.; Rinaldo, A.; Rodriguez-Iturbe, I.; Del Jesus, M.

    2013-05-01

    Hosting a large variety of vegetal and animal species, many of which rare or endangered, wetlands are among the most rich and vulnerable ecosystems in the world. Throughout the past century, the growing climatic impact and the increasing anthropogenic pressure have seriously threatened their natural equilibrium and substantially deteriorated their ecosystems. For fragility, biodiversity and extension, the Everglades is probably one of the most iconic wetlands in the world. After decades of land seizing and exploitation following the southward march of development in Florida, awareness of the importance of the Everglades wetlands has recently risen, bringing it to the center of one of the largest and most ambitious restoration projects ever attempted. Wetlands equilibrium and biodiversity are crucially linked to the hydrologic regime. In the Everglades, hydroperiods (i.e. percent of time a site is inundated) exert a critical control in the creation of habitat niches for different plant species. However, the feedbacks between the hydrologic signature and the plant dynamics that ultimately yield the observed spatial vegetation patterns are unknown. We identify both the main hydrologic and local drivers of the vegetation species spatial configuration and use them within a robust modeling framework able to reproduce the vegetation structures currently observed in the Everglades. By including both exogenous (i.e. hydrologic) and endogenous (i.e. local interactions) forcings, we are able to describe the mechanisms yielding to the observed power law behavior of the cluster size distribution of vegetation species. Since power law clustering is often associated with self-organization and systems near critical transitions, these findings can be successfully used to quantitatively assess the impact of potential climatic shifts and the effect of habitat loss or deterioration due to human activity, and can assist policy makers in identifying case-specific ecosystems restoration

  1. Surface elevation change and vegetation distribution dynamics in a subtropical coastal wetland: Implications for coastal wetland response to climate change

    NASA Astrophysics Data System (ADS)

    Rogers, Kerrylee; Saintilan, Neil; Woodroffe, Colin D.

    2014-08-01

    The response of coastal wetlands to sea-level rise is receiving global attention and observed changes in the distribution of mangrove and salt marsh are increasingly associated with global climate change, particularly sea-level and temperature rise, and potentially elevated carbon dioxide. Processes operating over smaller-spatial scales, such as rainfall variability and nutrient enrichment are also proposed as possible short-term drivers of changes in the distribution of mangrove and salt marsh. We consider the response of mangrove and salt marsh in a subtropical estuary to changes in environmental variables over a 12 year period by comparing rates of surface elevation change and vegetation distribution dynamics to hydrological and climatic variables, specifically water level and rainfall. This period of analysis captured inter-annual variability in sea level and rainfall associated with different phases of the El Niño Southern Oscillation (ENSO). We found that the mangrove and salt marsh trend of increasing elevation was primarily controlled by position within the tidal prism, in this case defined by inundation depth and distance to the tidal channel. Rainfall was not a primary driver of elevation trends in mangrove and salt marsh, but rainfall and water level variability did influence variability in elevation over the study period, though cross-correlation of these factors confounds identification of a single process driving this variability. These results highlight the scale-dependence of coastal wetland vegetation distribution dynamics; the longer-term trend of surface elevation increase and mangrove encroachment of salt marsh correlated with global sea-level trends, while short-term variability in surface elevation was related to local variability in water level and rainfall. Rates of surface elevation increase were found to lag behind rates of water level change within the Tweed River, which may facilitate further expansion of mangrove into salt marsh. This

  2. Hydrodynamics, vegetation transition and geomorphology coevolution in a semi-arid floodplain wetland.

    NASA Astrophysics Data System (ADS)

    Sandi, Steven; Rodriguez, Jose F.; Saco, Patricia M.; Riccardi, Gerardo; Wen, Li; Saintilan, Neil

    2016-04-01

    The Macquarie Marshes is a complex system of marshes, swamps and lagoons interconnected by a network of streams in the semi-arid region in north western NSW, Australia. The low-gradient topography of the site leads to channel breakdown processes where the river network becomes practically non-existent. As a result, the flow extends over large areas of wetland that later re-join and reform channels exiting the system. Vegetation in semiarid wetlands are often water dependent and flood tolerant species that rely on periodical floods in order to maintain healthy conditions. The detrimental state of vegetation in the Macquarie Marshes over the past few decades has been linked to decreasing inundation frequencies. Spatial distribution of flood tolerant overstory species such as River Red Gum and Black Box has not greatly changed since early 1990's, however; the condition of the vegetation patches shows a clear deterioration evidenced by terrestrial species encroachment on the wetland understory. On the other hand, areas of flood dependent species such as Water Couch and Common Reed have undergone complete succession to terrestrial species and dryland. In order to simulate the complex dynamics of the marshes we have developed an ecogeomorphological modelling framework that combines hydrodynamic, vegetation and channel evolution modules and in this presentation we provide an update on the status of the model. The hydrodynamic simulation provides spatially distributed values of inundation extent, duration, depth and recurrence to drive a vegetation model based on species preference to hydraulic conditions. It also provides velocities and shear stresses to assess geomorphological changes. Regular updates of stream network, floodplain surface elevations and vegetation coverage provide feedbacks to the hydrodynamic model. We presents also the development and assessment of transitional rules to determine if the water conditions have been met for different vegetation

  3. Wetland vegetation responses to liming an Adirondack watershed

    SciTech Connect

    Mackun, I.R.

    1993-01-01

    Watershed liming as a long-term mitigation strategy to neutralize lake acidity, from increasing acid deposition, was initiated in North America at Woods Lake in the west central Adirondack region of New York. In October 1989, a dose of 10 MT lime (83.5% CaCO[sub 3]) ha[sup [minus]1] was aerially applied to 48% of the watershed. The wetlands adjacent to Woods Lake showed two distinct community types: one dominated by Chamaedaphne calyculata, and one dominated by graminoids and other herbaceous species. Within two years, liming did not alter the structure of either community type, and changed the cover or frequency of only 6 of 64 individual taxa. Most of these changes occurred in the herbaceous community type. The only strong positive response to liming was a nearly threefold increase in cover of the rhizomatous sedge Cladium mariscoides. The cover of Carex interior and Sphagnum spp. benefited from lime addition, while cover of Drosera intermedia and Muhlenbergia uniflora, and frequency of Hypericum canadense responded negatively to lime. Liming influenced the competitive release of only three taxa, all forbs with small growth forms. The tissue chemistry of foliage and twigs of Myrica gale, Chamaedaphne calyculata, and Carex stricta in the Chamaedaphne calyculata community type clearly illustrated species-specific patterns of nutrient accumulation and allocation both before and after liming. Concentrations of 17 of 20 elements responded to liming, although the responses varied among species and plant parts. Carex foliage was least responsive to liming, and Chamaedaphne twigs were most responsive. Elemental changes in plant tissues will be reflected in litter and many influence long-term nutrient dynamics in the wetland community.

  4. An ecohydrological model for studying groundwater-vegetation interactions in wetlands

    NASA Astrophysics Data System (ADS)

    Chui, Ting Fong May; Low, Swee Yang; Liong, Shie-Yui

    2011-10-01

    SummaryDespite their importance to the natural environment, wetlands worldwide face drastic degradation from changes in land use and climatic patterns. To help preservation efforts and guide conservation strategies, a clear understanding of the dynamic relationship between coupled hydrology and vegetation systems in wetlands, and their responses to engineering works and climate change, is needed. An ecohydrological model was developed in this study to address this issue. The model combines a hydrology component based on the Richards' equation for characterizing variably saturated groundwater flow, with a vegetation component described by Lotka-Volterra equations tailored for plant growth. Vegetation is represented by two characteristic wetland herbaceous plant types which differ in their flood and drought resistances. Validation of the model on a study site in the Everglades demonstrated the capability of the model in capturing field-measured water table and transpiration dynamics. The model was next applied on a section of the Nee Soon swamp forest, a tropical wetland in Singapore, for studying the impact of possible drainage works on the groundwater hydrology and native vegetation. Drainage of 10 m downstream of the wetland resulted in a localized zone of influence within half a kilometer from the drainage site with significant adverse impacts on groundwater and biomass levels, indicating a strong need for conservation. Simulated water table-plant biomass relationships demonstrated the capability of the model in capturing the time-lag in biomass response to water table changes. To test the significance of taking plant growth into consideration, the performance of the model was compared to one that substituted the vegetation component with a pre-specified evapotranspiration rate. Unlike its revised counterpart, the original ecohydrological model explicitly accounted for the drainage-induced plant biomass decrease and translated the resulting reduced transpiration

  5. Energy and water balance response of a vegetated wetland to herbicide treatment of invasive Phragmites australis

    NASA Astrophysics Data System (ADS)

    Mykleby, Phillip M.; Lenters, John D.; Cutrell, Gregory J.; Herrman, Kyle S.; Istanbulluoglu, Erkan; Scott, Durelle T.; Twine, Tracy E.; Kucharik, Christopher J.; Awada, Tala; Soylu, Mehmet E.; Dong, Bo

    2016-08-01

    The energy and water balance of a Phragmites australis dominated wetland in south central Nebraska was analyzed to assess consumptive water use and the potential for "water savings" as a result of vegetation eradication via herbicide treatment. Energy balance measurements were made at the field site for two growing seasons (treated and untreated), including observations of net radiation, heat storage, and sensible heat flux, which was measured using a large-aperture scintillometer. Latent heat flux was calculated as a residual of the energy balance, and comparisons were made between the two growing seasons and with model simulations to examine the relative impacts of vegetation removal and climate variability. Observed ET rates dropped by roughly 32% between the two growing seasons, from a mean of 4.4 ± 0.7 mm day-1 in 2009 (with live vegetation) to 3.0 ± 0.8 mm day-1 in 2010 (with dead P. australis). These results are corroborated by the Agro-IBIS model simulations, and the reduction in ET implies a total "water savings" of 245 mm over the course of the growing season. The significant decreases in ET were accompanied by a more-than-doubling of sensible heat flux, as well as a ∼60% increase in heat storage due to decreased LAI. Removal of P. australis was also found to cause measurable changes in the local micrometeorology at the wetland. Consistent with the observed increase in sensible heat flux during 2010, warmer, drier, windier conditions were observed in the dead, P. australis section of the wetland, compared to an undisturbed section of live, native vegetation. Modeling results suggest that the elimination of transpiration in 2010 was partially offset by an increase in surface evaporation, thereby reducing the subsequent water savings by roughly 60%. Thus, the impact of vegetation removal depends on the local climate, depth to groundwater, and management decisions related to regrowth of vegetation.

  6. Vegetation-induced spatial variability of soil redox properties in wetlands

    NASA Astrophysics Data System (ADS)

    Szalai, Zoltán; Jakab, Gergely; Kiss, Klaudia; Ringer, Marianna; Balázs, Réka; Zacháry, Dóra; Horváth Szabó, Kata; Perényi, Katalin

    2016-04-01

    Vegetation induced land patches may result spatial pattern of on soil Eh and pH. These spatial pattern are mainly emerged by differences of aeration and exudation of assimilates. Present paper focuses on vertical extent and temporal dynamics of these patterns in wetlands. Two study sites were selected: 1. a plain wetland on calcareous sandy parent material (Ceglédbercel, Danube-Tisza Interfluve, Hungary); 2. headwater wetland with calcareous loamy parent material (Bátaapáti, Hungary). Two vegetation patches were studied in site 1: sedgy (dominated by Carex riparia) and reedy (dominated by Phragmites australis). Three patches were studied in site2: sedgy1 (dominated by C vulpina), sedgy 2 (C. riparia); nettle-horsetail (Urtica dioica and Equisetum arvense). Boundaries between patches were studied separately. Soil redox, pH and temperature studied by automated remote controlled instruments. Three digital sensors (Ponsell) were installed in each locations: 20cm and 40cm sensors represent the solum and 100 cm sensor monitors the subsoil). Groundwater wells were installed near to triplets for soil water sampling. Soil Eh, pH and temperature values were recorded in each 10 minutes. Soil water sampling for iron and DOC were carried out during saturated periods. Spatial pattern of soil Eh is clearly caused by vegetation. We measured significant differences between Eh values of the studied patches in the solum. We did not find this kinds horizontal differences in the subsoil. Boundaries of the patches usually had more reductive soil environment than the core areas. We have found temporal dynamics of the spatial redox pattern. Differences were not so well expressed during wintertime. These spatial patterns had influence on the DOC and iron content of porewater, as well. Highest temporal dynamics of soil redox properties and porewater iron could be found in the boundaries. These observations refer to importance patchiness of vegetation on soil chemical properties in

  7. Vegetation survey of Pen Branch and Four Mile Creek wetlands

    SciTech Connect

    Not Available

    1992-01-01

    One hundred-fifty plots were recently sampled (vegetational sampling study) at the Savannah River Site (SRS). An extensive characterization of the vascular flora, in four predetermined strata (overstory, Understory, shrub layer, and ground cover), was undertaken to determine dominance, co-dominance, and the importance value (I.V.) of each species. These results will be used by the Savannah River Laboratory (SRL) to evaluate the environmental status of Four Mile Creek, Pen Branch, and two upland pine stands. Objectives of this study were to: Describe in detail the plant communities previously mapped with reference to the topography and drainage, including species of plants present: Examine the successional trends within each sampling area and describe the extent to which current vegetation communities have resulted from specific earlier vegetation disturbances (e.g., logging and grazing); describe in detail the botanical field techniques used to sample the flora; describe the habitat and location of protected and/or rare species of plants; and collect and prepare plant species as herbarium quality specimens. Sampling was conducted at Four Mile Creek and Pen Branch, and in two upland pine plantations of different age growth.

  8. Vegetation survey of Pen Branch and Four Mile Creek wetlands

    SciTech Connect

    Not Available

    1992-10-01

    One hundred-fifty plots were recently sampled (vegetational sampling study) at the Savannah River Site (SRS). An extensive characterization of the vascular flora, in four predetermined strata (overstory, Understory, shrub layer, and ground cover), was undertaken to determine dominance, co-dominance, and the importance value (I.V.) of each species. These results will be used by the Savannah River Laboratory (SRL) to evaluate the environmental status of Four Mile Creek, Pen Branch, and two upland pine stands. Objectives of this study were to: Describe in detail the plant communities previously mapped with reference to the topography and drainage, including species of plants present: Examine the successional trends within each sampling area and describe the extent to which current vegetation communities have resulted from specific earlier vegetation disturbances (e.g., logging and grazing); describe in detail the botanical field techniques used to sample the flora; describe the habitat and location of protected and/or rare species of plants; and collect and prepare plant species as herbarium quality specimens. Sampling was conducted at Four Mile Creek and Pen Branch, and in two upland pine plantations of different age growth.

  9. Vegetation establishment on soil-amended weathered fly ash

    SciTech Connect

    Semalulu, O.; Barnhisel, R.I.; Witt, S.

    1998-12-31

    A field study was conducted with the following objectives in mind: (1) to study the effect of soil addition to weathered fly ash on the establishment and survival of different grasses and legumes, (2) to identify suitable grasses and/or legume species for vegetation of fly ash, (3) to study the fertilizer N and P requirements for successful vegetation establishment on fly ash and ash-soil mixtures, (4) to examine the nutrient composition of the plant species tested, and (5) to study the plant availability of P from fly ash and ash-soil mixtures. Three rooting media were used: weathered fly ash, and 33% or 50% soil blended with the ash. Four experiments were established on each of these media to evaluate warm season grasses in pure stands, warm season grasses inter-seeded with legumes, cool season grasses, and cool season grasses inter-seeded with legumes. Soil used in this study was more acidic than the fly ash. Only the results from characterization of the rooting media, ground cover, and yield will be presented here.

  10. Effects of Different Vegetation Zones on CH4 and N2O Emissions in Coastal Wetlands: A Model Case Study

    PubMed Central

    Liu, Yuhong; Wang, Lixin; Bao, Shumei; Liu, Huamin; Yu, Junbao; Wang, Yu; Shao, Hongbo; Ouyang, Yan; An, Shuqing

    2014-01-01

    The coastal wetland ecosystems are important in the global carbon and nitrogen cycle and global climate change. For higher fragility of coastal wetlands induced by human activities, the roles of coastal wetland ecosystems in CH4 and N2O emissions are becoming more important. This study used a DNDC model to simulate current and future CH4 and N2O emissions of coastal wetlands in four sites along the latitude in China. The simulation results showed that different vegetation zones, including bare beach, Spartina beach, and Phragmites beach, produced different emissions of CH4 and N2O in the same latitude region. Correlation analysis indicated that vegetation types, water level, temperature, and soil organic carbon content are the main factors affecting emissions of CH4 and N2O in coastal wetlands. PMID:24892044

  11. Integrating field sampling, spatial statistics and remote sensing to map wetland vegetation in the Pantanal, Brazil

    NASA Astrophysics Data System (ADS)

    Arieira, J.; Karssenberg, D.; de Jong, S. M.; Addink, E. A.; Couto, E. G.; Nunes da Cunha, C.; Skøien, J. O.

    2010-09-01

    To improve the protection of wetlands, it is imperative to have a thorough understanding of their structuring elements and of the identification of efficient methods to describe and monitor them. This article uses sophisticated statistical classification, interpolation and error propagation techniques, in order to describe vegetation spatial patterns, map plant community distribution and evaluate the capability of statistical approaches to produce high-quality vegetation maps. The approach results in seven vegetation communities with a known floral composition that can be mapped over large areas using remotely sensed data. The relations between remotely sensing data and vegetation patterns, captured in four factorial axes, were formalized mathematically in multiple linear regression models and used in a universal kriging procedure to reduce the uncertainty in mapped communities. Universal kriging has shown to be a valuable interpolation technique because parts of vegetation variability not explained by the images could be modeled as spatially correlated residuals, increasing prediction accuracy. Differences in spatial dependence of the vegetation gradients evidenced the multi-scale nature of vegetation communities. Cross validation procedures and Monte Carlo simulations were used to quantify the uncertainty in the resulting map. Cross-validation showed that accuracy in classification varies according with the community type, as a result of sampling density and configuration. A map of uncertainty resulted from Monte Carlo simulations displayed the spatial variation in classification accuracy, showing that the quality of classification varies spatially, even though the proportion and arrangement of communities observed in the original map is preserved to a great extent. These results suggested that mapping improvement could be achieved by increasing the number of field observations of those communities with a scattered and small patch size distribution; or by

  12. TTC Dyeing for Evaluation of Wetland Vegetation Activity in Sarobetsu Mire, Northern Japan

    NASA Astrophysics Data System (ADS)

    Hayashida, K.; Murakami, Y.; Mizugaki, S.; Yano, M.

    2011-12-01

    Reduced groundwater levels cause drying and shrinkage of mires, resulting in rapid changes in wetland vegetation. To conserve pre-existing wetland vegetation, it is important to clarify its behavior in relation to groundwater level fluctuations. Sarobetsu Mire, the biggest high moor in Japan, is experiencing a transition of its wetland vegetation due to increased invasion by dwarf bamboo (Sasa (Eusasa)). Previous studies have been limited to qualitative assessment concluding that the reduction of wetland vegetation areas is taking place. The invasion of dwarf bamboo was found to be inhibited in areas with high groundwater levels, but few studies have sought to quantitatively assess the responses of individual plants to groundwater variations. Growth activity has often been measured using the triphenyl-tetrazolium-chloride (TTC) method, which is a simple approach. The purpose of this study is to develop a quantitative method to assess the response (in terms of activity) of wetland vegetation to groundwater levels. To examine the relationship between the two (i.e., whether plants are dead or alive), a pair of laboratory experiments was conducted using the TTC method and absorptimetry with dwarf bamboo collected from Sarobetsu Mire. The first experiment was to investigate the activity of wetland vegetation in an inundated environment, and the second was to investigate annual fluctuations in such activity. The results showed that the activity (in terms of absorbance) of dwarf bamboo continued to decrease immediately after collection, and that the absorbance peak at a wavelength of 480 nm was also smaller. However, after the submersion period exceeded 30 days, there were no significant changes in absorbance as the submersion period went on. This indicates that dwarf bamboo underwent activity loss and died when the submersion period exceeded 30 days. Dwarf bamboo was considered dead when absorbance (480 nm) was 0.2 or lower and the peak became unclear. Since the change

  13. Microbial Transformations of Nitrogen, Sulfur, and Iron Dictate Vegetation Composition in Wetlands: A Review

    PubMed Central

    Lamers, Leon P. M.; van Diggelen, Josepha M. H.; Op den Camp, Huub J. M.; Visser, Eric J. W.; Lucassen, Esther C. H. E. T.; Vile, Melanie A.; Jetten, Mike S. M.; Smolders, Alfons J. P.; Roelofs, Jan G. M.

    2012-01-01

    The majority of studies on rhizospheric interactions focus on pathogens, mycorrhizal symbiosis, or carbon transformations. Although the biogeochemical transformations of N, S, and Fe have profound effects on vegetation, these effects have received far less attention. This review, meant for microbiologists, biogeochemists, and plant scientists includes a call for interdisciplinary research by providing a number of challenging topics for future ecosystem research. Firstly, all three elements are plant nutrients, and microbial activity significantly changes their availability. Secondly, microbial oxidation with oxygen supplied by radial oxygen loss from roots in wetlands causes acidification, while reduction using alternative electron acceptors leads to generation of alkalinity, affecting pH in the rhizosphere, and hence plant composition. Thirdly, reduced species of all three elements may become phytotoxic. In addition, Fe cycling is tightly linked to that of S and P. As water level fluctuations are very common in wetlands, rapid changes in the availability of oxygen and alternative terminal electron acceptors will result in strong changes in the prevalent microbial redox reactions, with significant effects on plant growth. Depending on geological and hydrological settings, these interacting microbial transformations change the conditions and resource availability for plants, which are both strong drivers of vegetation development and composition by changing relative competitive strengths. Conversely, microbial composition is strongly driven by vegetation composition. Therefore, the combination of microbiological and plant ecological knowledge is essential to understand the biogeochemical and biological key factors driving heterogeneity and total (i.e., microorganisms and vegetation) community composition at different spatial and temporal scales. PMID:22539932

  14. Soil Trace Gas Flux for Wetland Vegetation Zones in North Dakota Prairie Pothole Basins

    NASA Astrophysics Data System (ADS)

    Phillips, R. L.; Beeri, O.; Dekaiser, E. S.

    2003-12-01

    Wetland ecosystems are considered a source for radiatively trace gases [methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O)] but flux data for these greenhouse gases are lacking for depressional wetlands that comprise the Prairie Pothole Region. This region is characterized by thousands of small, closed basins that extend along the Missouri Coteau from north central Iowa to central Alberta. Surrounding each body of water are conspicuous zonation patterns given by specific vegetation life-forms and soil properties that are predominately formed by basin hydrology. Basin vegetation zones include deep marsh, shallow marsh, wet meadow, low prairie, and cropland (Stewart and Kantrud,1971). Our primary objective was to determine if net greenhouse gas flux for soils in these wetland basins [mg/m2/day CO2 equivalent (IPCC, 2000)] vary with vegetative zone for prairie pothole ecosystems. These data may then be used to map estimates for total basin greenhouse gas (GHG) flux. Additionally, we aimed to find the relative contribution of each of the 3 trace gases (CO2, CH4 and N2O) to net GHG flux. We hypothesized that flux would be greatest for marsh areas and lowest for upland areas. We selected a semi-permenant prairie pothole research site in Max, ND and mapped respective vegetative zones for 3 adjacent basins. Sample points were randomly selected for each basin and zone using aerial imagery. Samples of soil gases were collected using the static chamber method on August 3, 2003, and these were analyzed using gas chromatography for CO2, CH4 and N2O the following day. Soil moisture, clay content, organic matter, and temperature data were also collected. Net greenhouse gas flux for the cropped zone soils was significantly lower (p<0.01) than flux for the deep marsh, shallow marsh and wet meadow zone soils. Average flux measurement by zone (mg CO2 equivalent/m2/day) was 283 for cropland, 677 for low prairie, 1067 for wet meadow, 2572 for shallow marsh, and 6686 for deep

  15. Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration.

    PubMed

    Haukos, David A; Johnson, Lacrecia A; Smith, Loren M; McMurry, Scott T

    2016-10-01

    Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30-60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands. PMID:27423768

  16. Water temperature differences by plant community and location in re-established wetlands in the Sacramento-San Joaquin Delta, California, July 2005 to February 2008

    USGS Publications Warehouse

    Crepeau, Kathryn L.; Miller, Robin L.

    2014-01-01

    Rates of carbon storage in wetlands are determined by the balance of its inputs and losses, both of which are affected by environmental factors such as water temperature and depth. In the autumn of 1997, the U.S. Geological Survey re-established two wetlands with different shallow water depths—about 25 and 55 centimeters deep—to investigate the potential to reverse subsidence of delta islands by preserving and accumulating organic substrates derived from plant biomass inputs over time. Because cooler water temperatures can slow decomposition rates and increase accretion of plant biomass, water temperature was recorded from July 2005 to February 2008 in the deeper of the two wetlands, where areas of emergent and submerged vegetation persisted throughout the study, to assess differences in water temperature between the two vegetation types. Water temperature was compared at three depths in the water column between areas of emergent and submerged vegetation and between areas near the water inflow and in the wetland interior in both vegetation types. The latter comparison was a way of evaluating the effect of the length of time water had resided in the wetland on water temperatures. There were statistically significant differences in water temperature at all depths between the two vegetation types. Overall, in areas of emergent marsh vegetation, the mean water temperature at the surface was 1.4 degrees Celsius (°C) less than it was in areas of submerged vegetation; however, when analyses accounted for the changes in temperature due to seasonal and diurnal cycles, differences in the mean water temperature between the vegetation types were even greater than this. For example, in the spring, the mean temperatures in areas of emergent marsh vegetation at the surface, mid-point, and near the sediment in the water column were 2.0, 2.3, and 2.1 °C less, respectively, than water temperatures in areas of submerged vegetation. When diurnal changes in temperature were

  17. Establishment of vegetation on mined sites by management of mycorrhizae

    SciTech Connect

    Marrs, L.F.; Marx, D.H.; Cordell, C.E.

    1999-07-01

    Plant ecosystems, including those in the tropical, temperate, boreal, and desert zones, began evolving more than 400 million years ago. Trees and other land plants in these environments were faced with many natural stresses including extreme temperature changes, fluctuating levels of available water, soil infertility, catastrophic fires and storms, poor soil physical conditions and competition. Basically, these plants evolved by genetic selection and developed many physical, chemical, and biological requirements necessary to survive these periodically stressed environments. Survivors were those that could form extensive lateral root systems to occupy soil volumes sufficiently large for them to obtain enough essential mineral elements and water to support their above and below ground growth needs. The most competitive plants in these stressed ecosystems were those with the largest root systems. One major biological requirement that evolved was the association of plants with mycorrhizal fungi. This is still true today for land that has been disturbed by mining, construction, and other activities. Successful vegetation establishment on these lands has been achieved by using the biological tools; native tree seedlings, shrubs, forbs, and grasses inoculated with specific, beneficial mycorrhizal fungi. Trees and shrubs are custom grown in nurseries with selected mycorrhizal fungi, such as Pisolithus tinctorius (Pt) and other fungi, provide significant benefits to the plants through increased water and mineral adsorption, decreased toxin absorption and overall reduction of plant stress. This has resulted in significant increases in plant growth and survival rates, density and sustainable vegetation.

  18. Wind driven vertical transport in a vegetated, wetland water column with air-water gas exchange

    NASA Astrophysics Data System (ADS)

    Poindexter, C.; Variano, E. A.

    2010-12-01

    Flow around arrays of cylinders at low and intermediate Reynolds numbers has been studied numerically, analytically and experimentally. Early results demonstrated that at flow around randomly oriented cylinders exhibits reduced turbulent length scales and reduced diffusivity when compared to similarly forced, unimpeded flows (Nepf 1999). While horizontal dispersion in flows through cylinder arrays has received considerable research attention, the case of vertical dispersion of reactive constituents has not. This case is relevant to the vertical transfer of dissolved gases in wetlands with emergent vegetation. We present results showing that the presence of vegetation can significantly enhance vertical transport, including gas transfer across the air-water interface. Specifically, we study a wind-sheared air-water interface in which randomly arrayed cylinders represent emergent vegetation. Wind is one of several processes that may govern physical dispersion of dissolved gases in wetlands. Wind represents the dominant force for gas transfer across the air-water interface in the ocean. Empirical relationships between wind and the gas transfer coefficient, k, have been used to estimate spatial variability of CO2 exchange across the worlds’ oceans. Because wetlands with emergent vegetation are different from oceans, different model of wind effects is needed. We investigated the vertical transport of dissolved oxygen in a scaled wetland model built inside a laboratory tank equipped with an open-ended wind tunnel. Plastic tubing immersed in water to a depth of approximately 40 cm represented emergent vegetation of cylindrical form such as hard-stem bulrush (Schoenoplectus acutus). After partially removing the oxygen from the tank water via reaction with sodium sulfite, we used an optical probe to measure dissolved oxygen at mid-depth as the tank water re-equilibrated with the air above. We used dissolved oxygen time-series for a range of mean wind speeds to estimate the

  19. Vegetation composition and soil microbial community structural changes along a wetland hydrological gradient

    NASA Astrophysics Data System (ADS)

    Balasooriya, W. K.; Denef, K.; Peters, J.; Verhoest, N. E. C.; Boeckx, P.

    2007-10-01

    Fluctuations in wetland hydrology create an interplay between aerobic and anaerobic conditions, controlling vegetation composition and microbial community structure and activity in wetland soils. In this study, we investigated the vegetation composition and microbial community structural and functional changes along a wetland hydrological gradient. Two different vegetation communities were distinguished along the hydrological gradient; textit{Caricetum gracilis} at the wet depression and textit{Arrhenatherum elatioris} at the drier upper site. Microbial community structural changes were studied by a combined in situ 13CO2 pulse labeling and phospholipid fatty acid (PLFA) based stable isotope probing approach, which identifies the microbial groups actively involved in assimilation of newly photosynthesized, root-derived C in the rhizosphere soils. Gram negative bacterial communities were relatively more abundant in the surface soils of the drier upper site than in the surface soils of the wetter lower site, while the lower site and the deeper soil layers were relatively more inhabited by gram positive bacterial communities. Despite their large abundance, the metabolically active proportion of gram positive bacterial and actinomycetes communities was much smaller at both sites, compared to that of the gram negative bacterial and fungal communities. This suggests much slower assimilation of root-derived C by gram positive and actinomycetes communities than by gram negative bacteria and fungi at both sites. Ground water depth showed a significant effect on the relative abundance of several microbial communities. Relative abundance of gram negative bacteria was significantly decreased with increasing ground water depth while the relative abundance of gram positive bacteria and actinomycetes at the surface layer increased with increasing ground water depth.

  20. Vegetation composition and soil microbial community structural changes along a wetland hydrological gradient

    NASA Astrophysics Data System (ADS)

    Balasooriya, W. K.; Denef, K.; Peters, J.; Verhoest, N. E. C.; Boeckx, P.

    2008-02-01

    Fluctuations in wetland hydrology create an interplay between aerobic and anaerobic conditions, controlling vegetation composition and microbial community structure and activity in wetland soils. In this study, we investigated the vegetation composition and microbial community structural and functional changes along a wetland hydrological gradient. Two different vegetation communities were distinguished along the hydrological gradient; Caricetum gracilis at the wet depression and Arrhenatheretum elatioris at the drier upper site. Microbial community structural changes were studied by a combined in situ 13CO2 pulse labeling and phospholipid fatty acid (PLFA) based stable isotope probing approach, which identifies the microbial groups actively involved in assimilation of newly photosynthesized, root-derived C in the rhizosphere soils. Gram negative bacterial communities were relatively more abundant in the surface soils of the drier upper site than in the surface soils of the wetter lower site, while the lower site and the deeper soil layers were relatively more inhabited by gram positive bacterial communities. Despite their large abundance, the metabolically active proportion of gram positive bacterial and actinomycetes communities was much smaller at both sites, compared to that of the gram negative bacterial and fungal communities. This suggests much slower assimilation of root-derived C by gram positive and actinomycetes communities than by gram negative bacteria and fungi at both sites. Ground water depth showed a significant effect on the relative abundance of several microbial communities. Relative abundance of gram negative bacteria significantly decreased with increasing ground water depth while the relative abundance of gram positive bacteria and actinomycetes at the surface layer increased with increasing ground water depth.

  1. Wetland functional health assessment using remote sensing and other techniques: Literature search and overview. Technical memo

    SciTech Connect

    Patience, N.; Klemas, V.

    1993-03-01

    Contents: introduction; remote sensing of wetland biomass and other wetland condition indicators; conceptual approaches in wetland assessment; wetland extent and type; landscape and wetland patterns; wetland biomass and productivity; wetland vegetation; wetland habitat quality; wetland hydrology; and conclusions and recommendations.

  2. Effects of hydraulic resistance by vegetation on stage dynamics of a stormwater treatment wetland

    NASA Astrophysics Data System (ADS)

    Paudel, Rajendra; Grace, Kevin A.; Galloway, Stacey; Zamorano, Manuel; Jawitz, James W.

    2013-03-01

    SummaryThis work examined the potential effects of large-scale thinning of emergent vegetation on the stage dynamics in a very large (33.3 km2) constructed treatment wetland in South Florida. Dense vegetative biomass in treatment wetlands may restrict water flow and increase water levels, which may in turn have adverse effects on vegetative community structure. Here, we developed a physically-based, spatially-distributed hydrodynamic model of Stormwater Treatment Area 2, Cell 2 (STA2C2) to investigate the spatio-temporal variability of water level (stage) in response to management for thinning of emergent macrophytes (e.g., burning and/or herbicide treatments). The model was calibrated against stage measured at six monitoring stations for 1 year, and subsequently validated against 2 years of stage data from eight stations. Finally, the validated model was extended to simulate various vegetation management scenarios. The model provided an excellent fit to observed stage data in both calibration and validation periods (median model efficiency indices of 0.82 and 0.83, respectively). Higher stages in the treatment cell were dominantly associated with peak inflow magnitude and the timing of event intervals. Prolonged periods of sustained deep water conditions were observed when one flow peak was followed by consecutive peaks. A gradual stage gradient from the inlet to outlet was observed during peak flow periods, with a shift to a sharp gradient at approximately two-thirds distance from the inlet. Stages in the wetland were found to be controlled less by the hydraulic resistance, as indicated by a low sensitivity of simulated water levels for a ±50% perturbation in flow resistance parameter. Water depths were reduced by a maximum of 12 cm at the inlet region by thoroughly thinning the remaining emergent vegetation in STA2C2. Similarly, a maximum of only 2% of the total STA2C2 area was prevented from exceeding a water depth believed to be detrimental to Typha sp. (1

  3. Hydrologic and vegetative removal of Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii Surrogate microspheres in coastal wetlands.

    PubMed

    Hogan, Jennifer N; Daniels, Miles E; Watson, Fred G; Oates, Stori C; Miller, Melissa A; Conrad, Patricia A; Shapiro, Karen; Hardin, Dane; Dominik, Clare; Melli, Ann; Jessup, David A; Miller, Woutrina A

    2013-03-01

    Constructed wetland systems are used to reduce pollutants and pathogens in wastewater effluent, but comparatively little is known about pathogen transport through natural wetland habitats. Fecal protozoans, including Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii, are waterborne pathogens of humans and animals, which are carried by surface waters from land-based sources into coastal waters. This study evaluated key factors of coastal wetlands for the reduction of protozoal parasites in surface waters using settling column and recirculating mesocosm tank experiments. Settling column experiments evaluated the effects of salinity, temperature, and water type ("pure" versus "environmental") on the vertical settling velocities of C. parvum, G. lamblia, and T. gondii surrogates, with salinity and water type found to significantly affect settling of the parasites. The mesocosm tank experiments evaluated the effects of salinity, flow rate, and vegetation parameters on parasite and surrogate counts, with increased salinity and the presence of vegetation found to be significant factors for removal of parasites in a unidirectional transport wetland system. Overall, this study highlights the importance of water type, salinity, and vegetation parameters for pathogen transport within wetland systems, with implications for wetland management, restoration efforts, and coastal water quality. PMID:23315738

  4. A computer model to forecast wetland vegetation changes resulting from restoration and protection in coastal Louisiana

    USGS Publications Warehouse

    Visser, Jenneke M.; Duke-Sylvester, Scott M.; Carter, Jacoby; Broussard, Whitney P., III

    2013-01-01

    The coastal wetlands of Louisiana are a unique ecosystem that supports a diversity of wildlife as well as a diverse community of commercial interests of both local and national importance. The state of Louisiana has established a 5-year cycle of scientific investigation to provide up-to-date information to guide future legislation and regulation aimed at preserving this critical ecosystem. Here we report on a model that projects changes in plant community distribution and composition in response to environmental conditions. This model is linked to a suite of other models and requires input from those that simulate the hydrology and morphology of coastal Louisiana. Collectively, these models are used to assess how alternative management plans may affect the wetland ecosystem through explicit spatial modeling of the physical and biological processes affected by proposed modifications to the ecosystem. We have also taken the opportunity to advance the state-of-the-art in wetland plant community modeling by using a model that is more species-based in its description of plant communities instead of one based on aggregated community types such as brackish marsh and saline marsh. The resulting model provides an increased level of ecological detail about how wetland communities are expected to respond. In addition, the output from this model provides critical inputs for estimating the effects of management on higher trophic level species though a more complete description of the shifts in habitat.

  5. Fire-Vegetation-Microclimate Feedbacks under Simulated Global Change in Savanna - Wetland Ecotones

    NASA Astrophysics Data System (ADS)

    Just, M.; Hohmann, M. G.; Hoffmann, W. A.

    2015-12-01

    Boundaries between pyrogenic and adjacent pyrophobic vegetation communities are created and maintained by positive feedbacks between fire, vegetation, and microclimate. These feedbacks either promote or hinder fire and the boundary is situated at the transition from flammable to non-flammable. Consequently, vegetation is only directly influenced by fire if it is burned. Therefore, revealing where fire stops between communities is important for understanding their capacity to withstand change. We identified vegetation structure and microclimate components as predictors of fire spread along a (pyrogenic) savanna - (pyrophobic) wetland ecotonal gradient in North Carolina, USA. The ability of the fire feedback to maintain the transition from flammable to non-flammable conditions under potential global change is not known. We built a cellular automaton which employed Markov transition probabilities and associated fire spread probabilities to simulate the conditions of the ecotonal gradient under differing fire frequencies. Changes to the gradient boundaries were estimated from the location of the flammable to non-flammable transition. Our simulations produced movement of the boundary under certain fire return intervals. In general, more frequent fires resulted in fire failure deeper into wetland, and less frequent fires resulted in fire failure nearer savanna. Our simulations indicate that fire feedbacks are capable of controlling boundary locations up to a perturbation threshold, but that this control is not absolute. The transition from flammable to non-flammable within these pyrogenic-pyrophobic ecotones is essential to distinct communities. The management and conservation of these systems is fire-focused and, therefore, improving predictions about where fire stops under global change is important for those objectives.

  6. Development and testing the hydrological dynamics of vegetated wetland for CLM

    NASA Astrophysics Data System (ADS)

    Shi, X.; Thornton, P. E.; Ricciuto, D. M.; Hanson, P. J.; Mao, J.

    2013-12-01

    Northern peatlands store ~ 30% of the global soil carbon, though only representing ~ 3% of the Earth's land surface. Community Land Model (CLM) component of the Community Earth System Model (CESM) doesn't currently represent vegetated wetlands. To address this limitation, we incorporate key structural and process changes in the CLM. The model with new modifications will be informed and tested by Spruce and Peatland Responses Under Climatic and Environmental Change Experiment (SPRUCE). Our initial efforts have focused on model modifications needed to represent the isolated hydrologic cycle of the bog environment, as well as the observed patterning of the bog interior into raised hummocks and sunken hollows having distinct hydrologic dynamics and vegetation communities. The preliminary results of the hydrologic efforts show that the simulated water table heights for hummocks and hollows are consistent with observations, and the projected seasonal water table heights for the hummock/hollow topography are reasonable. Next steps for CLM-wetlands modeling are to calibrate the new hydrology treatment with vertically structured soil and CH4 sub-model, and to introduce Sphagnum hydrology and carbon cycle physiology. The comparison of CLM simulated and observed water table heights for year 2011 and 2012

  7. The influence of vegetation on sedimentation and resuspension of soil particles in small constructed wetlands.

    PubMed

    Braskerud, B C

    2001-01-01

    When initiatives to mitigate soil erosion are insufficient or fail, constructed surface flow wetlands (CWs) could be a final buffer to reduce pollution before reaching recipients. The objective of this study was to determine the influence of CW vegetation on the retention of soil particles from arable land. Retention was measured with water flow-proportional sampling systems in the inlet and outlet, sedimentation traps, and sedimentation plates in four small CWs over a period of 5 yr. The surface area of the CWs was 265 to 900 m2, and the average hydraulic loads were 1.2 to 3.4 m d(-1). Watershed areas were 0.5 to 1.5 km2. Annual soil particle retention was 30 to 80% or 14 to 121 kg m(-2). Results show that macrophytes stimulate sediment retention by mitigating resuspension of CW sediment. Five years after construction, resuspension had decreased approximately 40% and was negligible. As vegetation cover increases, the influence of macrophytes on soil particle retention reaches a level where other factors, such as hydraulic load and sediment load, were more important. Macrophytes increased the hydraulic efficiency by reducing short-circuit or preferential flow. However, vegetation did not have any influence on the clay concentration in the sediment. Hence, a possible stimulation of particle flocculation was not detected. Vegetation makes it possible to use the positive effect of a short particle settling distance in shallow ponds by hindering resuspension. PMID:11476524

  8. Effects of landscape gradients on wetland vegetation communities: information for large-scale restoration

    USGS Publications Warehouse

    Zweig, Christa L.; Kitchens, Wiley M.

    2008-01-01

    Projects of the scope of the restoration of the Florida Everglades require substantial information regarding ecological mechanisms, and these are often poorly understood. We provide critical base knowledge for Everglades restoration by characterizing the existing vegetation communities of an Everglades remnant, describing how present and historic hydrology affect wetland vegetation community composition, and documenting change from communities described in previous studies. Vegetation biomass samples were collected along transects across Water Conservation Area 3A South (3AS). Ten community types were present between November 2002 and 2005. Separate analyses for key a priori groups (slough, wet prairie, and sawgrass) provided detailed conclusions about effects of historic hydrology on the vegetation of 3AS. Communities were affected by hydrologic variables LIP to four years previous to the sample. We identified wet prairie/slough species such as Eleocharis spp. and Nymphaea odorata as short-term sentinel species of community change. Sawgrass and N. odorata should be monitored for long-term change. Comparisons to preceding studies indicated that many of the communities of previous times, when conditions were drier, no longer exist in our study area and have been replaced by deeper water community types.

  9. Recent Trends in Satellite Vegetation Index Observations Indicate Decreasing Vegetation Biomass in the Southeastern Saline Everglades Wetlands

    NASA Astrophysics Data System (ADS)

    Fuller, D. O.

    2013-12-01

    We analyzed trends in time series of the normalized difference vegetation index (NDVI) from multitemporal satellite imagery for 2001-2010 over the southeastern Everglades where major changes in vegetation structure and type have been associated with sea-level rise and reduced freshwater flow since the 1940s. Non-parametric trend analysis using the Theil-Sen slope revealed that 84.4% of statistically significant trends in NDVI were negative, mainly concentrated in scrub mangrove, sawgrass (Cladium jamaicense) and spike rush (Eleocharis cellulosa) communities within 5 km of the shoreline. Observed trends were consistent with trends in sawgrass biomass measurements made from 1999-2010 in three Long-term Ecological Research (LTER) sites within our study area. A map of significant trends overlaid on a RapidEye high-resolution satellite image showed large patches of negative trends parallel to the shoreline in and around the 'white zone,' which corresponds to a low-productivity band that has moved inland over the past 70 years. Significantly positive trends were observed mainly in the halophytic prairie community where highly salt tolerant species are typically found. Taken as a whole, the results suggest that increased saline intrusion associated with sea-level rise continues to reduce the photosynthetic biomass within freshwater and oligohaline marsh communities of the southeastern Everglades. Trends in 2001-2010 NDVI in southern saline Everglades wetlands of South Florida. a) slope values; b) areas of significant slope; c) location of the study area.

  10. Accounting for non-photosynthetic vegetation in remote-sensing-based estimates of carbon flux in wetlands

    USGS Publications Warehouse

    Schile, Lisa M.; Byrd, Kristin B.; Windham-Myers, Lisamarie; Kelly, Maggi

    2013-01-01

    Monitoring productivity in coastal wetlands is important due to their high carbon sequestration rates and potential role in climate change mitigation. We tested agricultural- and forest-based methods for estimating the fraction of absorbed photosynthetically active radiation (f APAR), a key parameter for modelling gross primary productivity (GPP), in a restored, managed wetland with a dense litter layer of non-photosynthetic vegetation, and we compared the difference in canopy light transmission between a tidally influenced wetland and the managed wetland. The presence of litter reduced correlations between spectral vegetation indices and f APAR. In the managed wetland, a two-band vegetation index incorporating simulated World View-2 or Hyperion green and near-infrared bands, collected with a field spectroradiometer, significantly correlated with f APAR only when measured above the litter layer, not at the ground where measurements typically occur. Measures of GPP in these systems are difficult to capture via remote sensing, and require an investment of sampling effort, practical methods for measuring green leaf area and accounting for background effects of litter and water.

  11. Late Quaternary climate and vegetation changes at Braamhoek wetland, South Africa

    NASA Astrophysics Data System (ADS)

    Norström, E.; Scott, L.; Finné, M.; Risberg, J.; Partridge, T. C.; Holmgren, K.

    2009-04-01

    This study contributes a continuous paleo-environmental record from Braamhoek wetland, eastern Free State, South Africa, covering the last 16 ka (16 000 cal yrs BP). The multi-proxy study includes analysis of microfossils (pollen, diatoms, phytoliths, charcoal fragments), stable isotopes (carbon and nitrogen) and lithological properties (carbon content, grain size). Braamhoek wetland is situated at an altitude of c. 1700 meters, a few kilometres north-west of the eastern escarpment, where the large difference in altitude results in orographic uplift of easterly air masses and annual rainfall is c. 1400 mm. The wetland is fed by ground-water springs, promoting continuous local wetness and organic preservation, which explains the accumulative conditions throughout Holocene and late Pleistocene. Analysis of fossil pollen suggests variations in vegetation patterns throughout the 16 ka period. The most important proxies for past vegetation are pollen of fynbos, forest trees, Poaceae and Asteraceae. Principal component analysis (PCA) was performed on 26 of the regional pollen taxa, yielding high positive loadings on forest trees and fynbos, which may reflect relatively moist conditions, particularly in combination with high representation of Poaceae pollen. The carbon isotope composition is a potential proxy for the relative abundance of C3 versus C4 grasses. The late Pleistocene carbon isotope values are probably an artefact of low carbon dioxide levels favouring C4 plants during late glacial conditions, while during the Holocene-Pleistocene transition and onwards, the isotopes probably reflect the local and regional C3/C4 grass ratio. The phytolith index gives additional information about environmental factors coupled to the grass distribution, while occurrences of planktonic diatoms indicate shifts in the moisture status within the wetland. We interpret depleted carbon isotope values, high PCA-score, high Poaceae/Asteraceae ratio, low phytolith index, as well as

  12. A test of vegetation-related indicators of wetland quality in the prairie pothole region

    USGS Publications Warehouse

    Kantrud, H.A.; Newton, W.E.

    1996-01-01

    This study was part of an effort by the U.S. Environmental Protection Agency to quantitatively assess the environmental quality or 'health' of wetland resources on regional and national scales. During a two-year pilot study, we tested selected indicators of wetland quality in the U.S. portion of the prairie pothole region (PPR). We assumed that the amount of cropland versus non-cropland (mostly grassland) in the plots containing these basins was a proxy for their quality. We then tested indicators by their ability to discriminate between wetlands at the extremes of that proxy. Amounts of standing dead vegetation were greater in zones of greater water permanence. Depth of litter was greater in zones of greater water permanence and in zones of basins in poor-quality watersheds. Amounts of unvegetated bottom were greater in basins in poor-quality watersheds; lesser amounts occurred in all wetlands during a wetter year. Greater amounts of open water occurred during a wetter year and in zones of greater water permanence. When unadjusted for areas (ha) of communities, plant taxon richness was higher in wet-meadow and shallow-marsh zones in good-quality watersheds than in similar zones in poor-quality watersheds. Wet-meadow zones in good-quality watersheds had greater numbers of native perennials than those in poor-quality watersheds. This relation held when we eliminated all communities in good-quality watersheds larger than the largest communities in poor-quality watersheds from the data set. We conclude that although amounts of unvegetated bottom and plant taxon richness in wet-meadow zones were useful indicators of wetland quality during our study, the search for additional such indicators should continue. The value of these indicators may change with the notoriously unstable hydrological conditions in the PPR. Most valuable would be indicators that could be photographed or otherwise remotely sensed and would remain relatively stable under various hydrological

  13. Evaluating the effect of rainfall variability on vegetation establishment in a semidesert grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Of the operations required for reclamation in arid and semi-arid regions, establishing vegetation entails the most uncertainty due to reliance on unpredictable rainfall for seed germination and seedling establishment. The frequency of successful vegetation establishment was estimated based on a land...

  14. Wetlands.

    ERIC Educational Resources Information Center

    Nelson, Patricia L.

    1986-01-01

    Suggests studying New York's wetlands, both in the classroom and in the field, to illustrate ecological concepts of diversity, succession, and adaptation and to learn about their importance in controlling flooding, erosion, and pollution. (NEC)

  15. Influence of varying nutrient and pesticide mixtures on abatement efficiency using a vegetated free water surface constructed wetland mesocosm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficiency of a vegetated free water surface constructed wetland in abating agrichemicals was examined using varying types of pollutant mixtures. Three different mixture conditions were assessed: nutrients only (N and P); pesticides only (2 herbicides and 1 insecticide); and a mixture of nutrie...

  16. Flora and ecological profile of native and exotic estuarine wetland vegetation by hydrogeomorphic setting at Rush Ranch, Suisun Marsh

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The manuscript includes a profile of the ecology and distribution of estuarine wetland vegetation at the Rush Ranch reserve site in the brackish Suisun Marsh reach of San Francisco Estuary The data and analyses will serve as a baseline for future scientific research and conservation management. A ...

  17. Assessing environmental impacts of constructed wetland effluents for vegetable crop irrigation.

    PubMed

    Castorina, A; Consoli, S; Barbagallo, S; Branca, F; Farag, A; Licciardello, F; Cirelli, G L

    2016-01-01

    The objective of this study was to monitor and assess environmental impacts of reclaimed wastewater (RW), used for irrigation of vegetable crops, on soil, crop quality and irrigation equipment. During 2013, effluents of a horizontal sub-surface flow constructed treatment wetland (TW) system, used for tertiary treatment of sanitary wastewater from a small rural municipality located in Eastern Sicily (Italy), were reused by micro-irrigation techniques to irrigate vegetable crops. Monitoring programs, based on in situ and laboratory analyses were performed for assessing possible adverse effects on water-soil-plant systems caused by reclaimed wastewater reuse. In particular, experimental results evidenced that Escherichia coli content found in RW would not present a risk for rotavirus infection following WHO (2006) standards. Irrigated soil was characterized by a certain persistence of microbial contamination and among the studied vegetable crops, lettuce responds better, than zucchini and eggplants, to the irrigation with low quality water, evidencing a bettering of nutraceutical properties and production parameters. PMID:26344169

  18. [Effects of soil factors on vegetation community structure in an abandoned subtropical paddy wetland].

    PubMed

    Peng, Yi; Li, Yu-Yuan; Li, Zhong-Wu; Ye, Fang-Yi; Pan, Chun-Xiang; Xie, Xiao-Li

    2009-07-01

    Based on the investigation data from a subtropical wetland having been abandoned from paddy agriculture for one year, a redundancy analysis was conducted on the relationships between vegetation community and soil factors in the wetland. It was found that soil moisture regime, available K and P, and pH were the main factors affecting the distribution of plant species. The common plant species could be classified into three groups, i. e., Ludwigia prostrata - Murdannia triquetra group (G1), Hemarthria altissima - Rotala rotundifolia - Lapsana apogonoides group (G2), and Conyza canadensis - Polygonum hydropiper - Paspalum pasaloides group (G3). G1 mainly distributed on the soils with higher available K, G2 mainly distributed in periodically flooded area, while G3 mainly distributed in drainage area and was positively correlated to soil available P and pH. Species diversity and above-ground biomass had significant positive correlations with soil pH and total K, respectively, while evenness index was significantly negatively correlated with soil available N. No significant correlations were observed among other indices. PMID:19899449

  19. Vegetation, substrate and hydrology in floating marshes in the Mississippi river delta plain wetlands, USA

    USGS Publications Warehouse

    Sasser, C.E.; Gosselink, J.G.; Swenson, E.M.; Swarzenski, C.M.; Leibowitz, N.C.

    1996-01-01

    In the 1940s extensive floating marshes (locally called 'flotant') were reported and mapped in coastal wetlands of the Mississippi River Delta Plain. These floating marshes included large areas of Panicum hemitomon-dominated freshwater marshes, and Spartina patens/Scirpus olneyi brackish marshes. Today these marshes appear to be quite different in extent and type. We describe five floating habitats and one non-floating, quaking habitat based on differences in buoyancy dynamics (timing and degree of floating), substrate characteristics, and dominant vegetation. All floating marshes have low bulk density, organic substrates. Nearly all are fresh marshes. Panicum hemitomon floating marshes presently occur within the general regions that were reported in the 1940's by O'Neil, but are reduced in extent. Some of the former Panicum hemitomon marshes have been replaced by seasonally or variably floating marshes dominated, or co-dominated by Sagittaria lancifolia or Eleocharis baldwinii. ?? 1996 Kluwer Academic Publishers.

  20. Derivation of Ground Surface and Vegetation in a Coastal Florida Wetland with Airborne Laser Technology

    USGS Publications Warehouse

    Raabe, Ellen A.; Harris, Melanie S.; Shrestha, Ramesh L.; Carter, William E.

    2008-01-01

    The geomorphology and vegetation of marsh-dominated coastal lowlands were mapped from airborne laser data points collected on the Gulf Coast of Florida near Cedar Key. Surface models were developed using low- and high-point filters to separate ground-surface and vegetation-canopy intercepts. In a non-automated process, the landscape was partitioned into functional landscape units to manage the modeling of key landscape features in discrete processing steps. The final digital ground surface-elevation model offers a faithful representation of topographic relief beneath canopies of tidal marsh and coastal forest. Bare-earth models approximate field-surveyed heights by + 0.17 m in the open marsh and + 0.22 m under thick marsh or forest canopy. The laser-derived digital surface models effectively delineate surface features of relatively inaccessible coastal habitats with a geographic coverage and vertical detail previously unavailable. Coastal topographic details include tidal-creek tributaries, levees, modest topographic undulations in the intertidal zone, karst features, silviculture, and relict sand dunes under coastal-forest canopy. A combination of laser-derived ground-surface and canopy-height models and intensity values provided additional mapping capabilities to differentiate between tidal-marsh zones and forest types such as mesic flatwood, hydric hammock, and oak scrub. Additional derived products include fine-scale shoreline and topographic profiles. The derived products demonstrate the capability to identify areas of concern to resource managers and unique components of the coastal system from laser altimetry. Because the very nature of a wetland system presents difficulties for access and data collection, airborne coverage from remote sensors has become an accepted alternative for monitoring wetland regions. Data acquisition with airborne laser represents a viable option for mapping coastal topography and for evaluating habitats and coastal change on marsh

  1. Regeneration of vegetation on wetland crossings for gas pipeline rights-of-way one year after construction

    SciTech Connect

    Shem, L.M.; Zimmerman, R.E.; Zellmer, S.D.; Van Dyke, G.D.; Rastorfer, J.R.

    1993-10-01

    Four wetland crossings of gas pipeline rights-of-way (ROWs), located in Florida, Michigan, New Jersey, and New York, were surveyed for generation of vegetation roughly one year after pipeline construction was completed. Conventional trench-and-fill construction techniques were employed for all four sites. Estimated areal coverage of each species by vegetative strata within transect plots was recorded for plots on the ROW and in immediately adjacent wetlands undisturbed by construction activities. Relative success of regeneration was measured by percent exposed soil, species diversity, presence of native and introduced species, and hydric characteristics of the vegetation. Variable site factors included separation and replacement of topsoil, final grading of the soil, application of seed and fertilizer, and human disturbance unrelated to construction. Successful regeneration exhibited greater dependency on the first three factors listed.

  2. 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

  3. Wetland vegetation and nutrient retention in Nakivubo and Kirinya wetlands in the Lake Victoria basin of Uganda

    NASA Astrophysics Data System (ADS)

    Mugisha, P.; Kansiime, F.; Mucunguzi, P.; Kateyo, E.

    Wetlands form an important part of the catchment area of the African Great Lakes and protect water resources therein. One of the most important functions is the retention of nutrients from the inflowing water from the catchment, by wetland plants which store them in their phytomass. An assessment of the capacity in storing nutrients by dominant plants ( Cyeprus papyrus, Miscanthus violaceus, Phragmites mauritianus and Colocasia C. esculenta), of Nakivubo and Kirinya wetlands at the shores of Lake Victoria in Uganda, was studied through the determination of phytomass production and nutrient concentration in the plant parts at different stages of growth. The above ground phytomass production increased rapidly during the exponential growth for C. papyrus and P. mauritianus. In all the dominant plants, nitrogen concentration was highest in juvenile plants and decreased with increasing age. The most pronounced nitrogen level occurred in the young umbels of C. papyrus during the first month of growth with total nitrogen content of 1.95% DW which dropped to 0.62% DW after the fifth month in Nakivubo wetland. Corms (tubers) of yams had the highest nitrogen content in Kirinya and Nakivubo wetlands exhibiting respective values of 4.8% DW and 3.7% DW. There is a close relationship between nutrient content and increase in phytomass. In Nakivubo and Kirinya wetlands, the rapid increase in phytomass during the third and fourth month corresponded with high nutrient levels. Since plants store significant amounts of nitrogen during their growth, periodic harvesting of above ground plant parts can remove significant amounts of nutrients (during the first five months of growth) from the wastewater flowing into the two wetlands. Wetland plant species with high phytomass productivity and well developed root systems and ability to withstand flooding are the best in nutrient removal.

  4. A demonstration of wetland vegetation mapping in Florida from computer-processed satellite and aircraft multispectral scanner data

    NASA Technical Reports Server (NTRS)

    Butera, M. K. (Principal Investigator)

    1978-01-01

    The author has identified the following significant results. Major vegetative classes identified by the remote sensing technique were cypress swamp, pine, wetland grasses, salt grass, mixed mangrove, black mangrove, Brazilian pepper. Australian pine and melaleuca were not satisfactorily classified from LANDSAT. Aircraft scanners provided better resolution resulting in a classification of finer surface detail. An edge effect, created by the integration of diverse spectral responses within boundary elements of digital data, affected the wetlands classification. Accuracy classification for aircraft was 68% and for LANDSAT was 74%.

  5. Revising Vegetation Scattering Theories: Adding A Rotated Dihedral Double Bounce Scattering To Explain Cross-Polarimetric SAR Observations Over Wetlands

    NASA Astrophysics Data System (ADS)

    Hong, Sang-Hoon; Wdowinski, Shimon

    2012-01-01

    Common vegetation scattering theories indicate that short wavelength Synthetic Aperture Radar (SAR) observations (X- and C-band) measure mainly vegetation canopies as the short-wavelength radar signal interacts mostly with upper sections of the vegetation. Furthermore, these theories also suggest that SAR cross- polarization (cross-pol) observations reflect only volume scattering. Consequently most SAR decomposition techniques assume that the cross-pol signal represents solely volume scattering. However, short-wavelength and cross-pol observations from the Everglades wetlands, south Florida, suggest that a significant portion of the SAR signal scatters from the surface and not only from the upper sections of the vegetation. The indication for surface scattering in wetland environment is derived from phase observable processed using interferometric techniques. The interferometric SAR (InSAR) observations reveal coherent phase signal in all polarizations and all wavelengths, reflecting water level changes beneath the vegetation. This coherent phase signal cannot be explained by neither volume scattering nor radar signal interaction with the upper sections of the vegetations, because canopies and branches are frequently move by wind. The only way that such coherent signal can be maintained and represents surface water level changes is when a multiple bounce from the vegetation and surface occurs. The simplest multi-bounce scattering mechanism that generate cross-pol signal occurs by rotated dihedrals. Thus, we use the rotated dihedral mechanism to explain the InSAR wetland observations and to revise the current vegetation scattering theories to accounts also for double bounce component in cross-pol observations.

  6. Uncertainty of establishment scheme in the Community Land Model-Dynamic Global Vegetation Model

    NASA Astrophysics Data System (ADS)

    Song, X.; Zeng, X.

    2010-12-01

    Dynamic global vegetation models are very important tools to simulate and predict the relationship between terrestrial ecosystem processes and climate change. They usually consist of several main sub-models, such as establishment, growth, mortality due to stress, competition, reproductive and so forth. In this study, we focus on the establishment sub-model. Establishment sub-model describes the processes of germination of tree seeds and establishment of seedlings. However, due to the complexity of the ecological process and the lack of observation data, current DGVMs use different parameterization schemes of establishment, and the uncertainties of these establishment scheme as well as their impacts on vegetation distribution remain largely unknown. Our work is to introduce several new different establishment schemes, each based on different physical and ecological considerations, into a modified Community Land Model - Dynamic Global Vegetation Model (CLM-DGVM). The sensitivities of the vegetation distribution to different establishment schemes and some essential parameters in the schemes are investigated in different vegetation zones. Our research indicates that establishment scheme has remarkable effects not only on the percent of coverage and population density of different plant functional types (PFTs) but also the community structure such as coexistence of PFTs and even the dominant vegetation. Such changes will alter the ecosystem functioning, and hence have further impacts on climate through the vegetation-atmosphere feedback.

  7. Patch-Scale Effects of Equine Disturbance on Arthropod Assemblages and Vegetation Structure in Subalpine Wetlands

    NASA Astrophysics Data System (ADS)

    Holmquist, Jeffrey G.; Schmidt-Gengenbach, Jutta; Ballenger, Elizabeth A.

    2014-06-01

    Assessments of vertebrate disturbance to plant and animal assemblages often contrast grazed versus ungrazed meadows or other larger areas of usage, and this approach can be powerful. Random sampling of such habitats carries the potential, however, for smaller, more intensely affected patches to be missed and for other responses that are only revealed at smaller scales to also escape detection. We instead sampled arthropod assemblages and vegetation structure at the patch scale (400-900 m2 patches) within subalpine wet meadows of Yosemite National Park (USA), with the goal of determining if there were fine-scale differences in magnitude and directionality of response at three levels of grazing intensity. Effects were both stronger and more nuanced than effects evidenced by previous random sampling of paired grazed and ungrazed meadows: (a) greater negative effects on vegetation structure and fauna in heavily used patches, but (b) some positive effects on fauna in lightly grazed patches, suggested by trends for mean richness and total and population abundances. Although assessment of disturbance at either patch or landscape scales should be appropriate, depending on the management question at hand, our patch-scale work demonstrated that there can be strong local effects on the ecology of these wetlands that may not be detected by comparing larger scale habitats.

  8. Mapping vegetation of a wetland ecosystem by fuzzy classification of optical and microwave satellite images supported by various ancillary data

    NASA Astrophysics Data System (ADS)

    Stankiewicz, Krystyna; Dabrowska-Zielinska, Katarzyna; Gruszczynska, Maryla; Hoscilo, Agata

    2003-03-01

    An approach to classification of satellite images aimed at vegetation mapping in a wetland ecosystem has been presented. The wetlands of the Biebrza Valley located in the NE part of Poland has been chosen as a site of interest. The difficulty of using satellite images for the classification of a wetland land cover lies in the strong variability of the hydration state of such ecosystem in time. Satellite images acquired by optical or microwave sensors depend heavily on the current water level which often masks the most interesting long-time scale features of vegetation. Therefore the images have to be interpreted in the context of various ancillary data related to the investigated site. In the case of Biebrza Valley the most useful information was obtained from the soil and hydration maps as well as from the old vegetation maps. The object oriented classification approach applied in eCognition software enabled simultaneous use of satellite images together with the additional thematic data. Some supplementary knowledge concerning possible plant cover changes was also introduced into the process of classification. The accuracy of the classification was assessed versus ground-truth data and results of visual interpretation of aerial photos. The achieved accuracy depends on the type of vegetation community in question and is better for forest or shrubs than for meadows.

  9. A numerical study of vegetation impact on reducing storm surge by wetlands in a semi-enclosed estuary

    USGS Publications Warehouse

    Kelin, Hu; Qin, Chen; Wang, Hongqing

    2014-01-01

    Coastal wetlands play a unique role in extreme hurricane events. The impact of wetlands on storm surge depends on multiple factors including vegetation, landscape, and storm characteristics. The Delft3D model, in which vegetation effects on flow and turbulence are explicitly incorporated, was applied to the semi-enclosed Breton Sound (BS) estuary in coastal Louisiana to investigate the wetland impact. Guided by extensive field observations, a series of numerical experiments were conducted based on variations of actual vegetation properties and storm parameters from Hurricane Isaac in 2012. Both the vegetation-induced maximum surge reduction (MSR) and maximum surge reduction rate (MSRR) increased with stem height and stem density, and were more sensitive to stem height. The MSR and MSRR decreased significantly with increasing wind intensity. The MSRR was the highest with a fast-moving weak storm. It was also found that the MSRR varied proportionally to the expression involving the maximum bulk velocity and surge over the area of interest, and was more dependent on the maximum bulk surge. Both MSR and MSRR appeared to increase when the area of interest decreased from the whole BS estuary to the upper estuary. Within the range of the numerical experiments, the maximum simulated MSR and MSRR over the upper estuary were 0.7 m and 37%, respectively.

  10. Vegetation effects on floating treatment wetland nutrient removal and harvesting strategies in urban stormwater ponds.

    PubMed

    Wang, Chih-Yu; Sample, David J; Bell, Cameron

    2014-11-15

    Floating treatment wetlands (FTWs) consist of emergent macrophytes that are placed on a floating mat in a pond for water treatment and aesthetic purposes. FTWs may have unique advantages with respect to treating urban runoff within existing retention ponds for excess nutrients. However, research is lacking in providing guidance on performance of specific species for treating urban runoff, and on timing of harvest. Harvesting is needed to remove nutrients permanently from the retention pond. We investigated vegetation effects on FTWs on nitrogen (N) and phosphorus (P) removal performance and storage in above-ground FTW macrophyte tissues. The study evaluated pickerelweed (PW, Pontederia cordata L.) and softstem bulrush (SB, Schoenoplectus tabernaemontani) over time in microcosms flushed with water obtained from a nearby urban retention pond in northern Virginia near Washington, DC. While the literature exhibits a wide range of experimental sizes, using the term mesocosm, we have chosen the term microcosm to reflect the small size of our vessel; and do not include effects of sediment. The experiment demonstrated PW outperformed SB for P and N removal. Based upon analysis of the accumulated nutrient removal over time, a harvest of the whole PW and SB plants in September or October is recommended. However, when harvesting only the aerial parts, we recommend harvesting above-ground PW tissues in July or August to maximize nutrient removal. This is because PW translocates most of its nutrients to below-ground storage organs in the fall, resulting in less nutrient mass in the above-ground tissue compared to the case in the summer (vegetative stage). Further research is suggested to investigate whether vegetation can be overly damaged from multiple harvests on an annual basis in temperate regions. PMID:25214393

  11. Prototype Application of NASA Missions to Identify Patterns of Wetland Vegetation Development within the South San Francisco Bay Salt Ponds

    NASA Astrophysics Data System (ADS)

    Hsu, W.; Newcomer, M. E.; Justice, E.; Guild, L. S.; Skiles, J. W.

    2010-12-01

    The South Bay Salt Pond Restoration Project is the largest tidal wetland restoration on the west coast of the United States. Monitoring vegetation development in these emergent habitats with remote sensing can provide restoration managers with an indication of ecological health and progress of development. Remotely sensed imagery was used to monitor vegetation development and to map vegetation patterns and biota changes historically, during, and after salt pond construction for ponds A19, A20, and A21. Percent vegetative cover was mapped using the Normalized Difference Vegetation Index (NDVI) from MODIS, Tasseled Cap Greenness (TCG) and NDVI from Landsat TM, and the Ratio Vegetation Index (RVI) from ASTER. Field parameters included in-situ measurements and geographic locations for percent vegetative cover, and site specific species information. Field data were incorporated into GIS, and vegetation was analyzed using spatial statistics methods and a qualitative post-classification comparison technique. NDVI values obtained from the Landsat scenes indicated a net gain of 3.35 acres of vegetation cover from February 2006 (before pond breaching) to August 2009 for pond A21 and 1.33 acres and 3.14 acres for ponds A20 and A19, respectively. Increases in vegetation indicate the marsh has built up to a steady-state condition to provide appropriate habitat for endangered plant and animal species and also indicates the success of restoration practices.

  12. Changes in vegetative coverage of the Hongze Lake national wetland nature reserve: a decade-long assessment using MODIS medium-resolution data

    NASA Astrophysics Data System (ADS)

    Yu, Kun; Hu, Chuanmin

    2013-01-01

    Wetlands are important ecosystems on Earth. However, global wetland coverage is being reduced due to both anthropogenic and natural effects. Thus, assessment of temporal changes in vegetative coverage, as a measure of the wetland health, is critical to help implement effective management plans and provide inputs for climate-related research. In this work, 596 moderate-resolution imaging spectroradiometer (MODIS) 250-m resolution images of the Hongze Lake national wetland nature reserve from 2000 to 2009 were used to study the vegetative coverage (above the water surface) of the reserve. Three vegetation indices [normalized difference vegetation index (NDVI), enhanced VI (EVI), and floating algae index (FAI)] were compared to evaluate their effectiveness in assessing relative changes. FAI was less sensitive than NDVI and EVI to aerosol effects and showed less statistical error than NDVI and EVI. Long-term FAI data revealed clear seasonal cycles in vegetative coverage in the 113-km2 core area of the reserve, with annual maximal coverage relatively stable after 2004. This suggests that the national wetland nature reserve was well protected through the study period. However, vegetative coverage decreased due to the flooding event in 2003. Moreover, correlation analysis showed that annual sunshine duration collectively played a significant role in affecting the wetland vegetative coverage.

  13. Comparison of carbon balance in Mediterranean pilot constructed wetlands vegetated with different C4 plant species.

    PubMed

    Barbera, Antonio C; Borin, Maurizio; Cirelli, Giuseppe L; Toscano, Attilio; Maucieri, Carmelo

    2015-02-01

    This study investigates carbon dioxide (CO2) and methane (CH4) emissions and carbon (C) budgets in a horizontal subsurface flow pilot-plant constructed wetland (CW) with beds vegetated with Cyperus papyrus L., Chrysopogon zizanioides (L.) Roberty, and Mischantus × giganteus Greef et Deu in the Mediterranean basin (Sicily) during the 1st year of plant growing season. At the end of the vegetative season, M. giganteus showed the higher biomass accumulation (7.4 kg m(-2)) followed by C. zizanioides (5.3 kg m(-2)) and C. papyrus (1.8 kg m(-2)). Significantly higher emissions of CO2 were detected in the summer, while CH4 emissions were maximum during spring. Cumulative CO2 emissions by C. papyrus and C. zizanioides during the monitoring period showed similar trends with final values of about 775 and 1,074 g m(-2), respectively, whereas M. giganteus emitted 3,395 g m(-2). Cumulative CH4 bed emission showed different trends for the three C4 plant species in which total gas release during the study period was for C. papyrus 12.0 g m(-2) and ten times higher for M. giganteus, while C. zizanioides bed showed the greatest CH4 cumulative emission with 240.3 g m(-2). The wastewater organic carbon abatement determined different C flux in the atmosphere. Gas fluxes were influenced both by plant species and monitored months with an average C-emitted-to-C-removed ratio for C. zizanioides, C. papyrus, and M. giganteus of 0.3, 0.5, and 0.9, respectively. The growing season C balances were positive for all vegetated beds with the highest C sequestered in the bed with M. giganteus (4.26 kg m(-2)) followed by C. zizanioides (3.78 kg m(-2)) and C. papyrus (1.89 kg m(-2)). To our knowledge, this is the first paper that presents preliminary results on CO2 and CH4 emissions from CWs vegetated with C4 plant species in Mediterranean basin during vegetative growth. PMID:24743957

  14. Removal of organic pollutants from oak leachate in pilot scale wetland systems: How efficient are aeration and vegetation treatments?

    PubMed

    Svensson, Henric; Ekstam, Börje; Marques, Marcia; Hogland, William

    2015-11-01

    This study investigated the effects of aeration and/or vegetation in experimental constructed wetlands (CWs) as mesocosms on the removal of pollutants in oak wood leachate. Twelve outdoor wetland mesocosms, with randomized replicated treatment combinations of vegetation (Phragmites australis) and aeration was monitored during the second and third year after construction. The investigation included control tanks with no aeration and no vegetation. The parameters monitored were polyphenols (PPs), chemical oxygen demand (COD) and water colour. The reduction of COD after 28 days was approx. 50% and more than 50% of PPs, whereas only 40% of the water colour was removed. Aeration increased the effect of both COD and PP removal. The vegetation treatment had a small but significant effect on removal of COD. The vegetation + aeration treatment, as well as aeration alone, increased the removal efficiency of COD from 9.5 g m(-3) d(-1) in the control to 11 g m(-3) d(-1). The results suggest that CWs can be used to treat stormwater contaminated by oak wood leachate. Further, it is suggested that the main processes for removal of pollutants in the leachate occur in the open-water habitat and that the hydraulic retention time is more important for removal than aeration and vegetation related processes. PMID:26218465

  15. Hydrologic, vegetation, and soil data collected in selected wetlands of the Big River Management area, Rhode Island, from 2008 through 2010

    USGS Publications Warehouse

    Borenstein, Meredith S.; Golet, Francis C.; Armstrong, David S.; Breault, Robert F.; McCobb, Timothy D.; Weiskel, Peter K.

    2012-01-01

    The Rhode Island Water Resources Board planned to develop public water-supply wells in the Big River Management Area in Kent County, Rhode Island. Research in the United States and abroad indicates that groundwater withdrawal has the potential to affect wetland hydrology and related processes. In May 2008, the Rhode Island Water Resources Board, the U.S. Geological Survey, and the University of Rhode Island formed a partnership to establish baseline conditions at selected Big River wetland study sites and to develop an approach for monitoring potential impacts once pumping begins. In 2008 and 2009, baseline data were collected on the hydrology, vegetation, and soil characteristics at five forested wetland study sites in the Big River Management Area. Four of the sites were located in areas of potential drawdown associated with the projected withdrawals. The fifth site was located outside the area of projected drawdown and served as a control site. The data collected during this study are presented in this report.

  16. After the deluge: Establishing rates of geographically isolated wetland loss within the prairie pothole region

    NASA Astrophysics Data System (ADS)

    Serran, J.; Creed, I. F.

    2014-12-01

    Geographically isolated wetlands (GIWs) from the prairie pothole region of North America are particularly vulnerable to loss and increasing urban, agricultural, and natural resource development pressures continue to place these wetlands at risk. Although small in area and low in surface hydrologic connectivity, GIWs provide important functions such as flood control and water purification and their loss has been recognized as a contributing factor to the eutrophication of Lake Winnipeg. Within Canada, GIW loss can be attributed to the lack of high-resolution wetland inventories and the lack of information about historic wetland loss rates. In this study, we tested an approach to estimate GIW loss by improving their detection and delineation. To initialize our work, a high-resolution wetland inventory was created using a novel approach that fuses LiDAR data (probability of wetland) with aerial photographs (to distinguish open water and wet meadow) for the Beaverhill watershed, a major tributary of the North Saskatchewan watershed. Our wetland mapping results validated our ability to detect wetlands on the landscape. Secondly, we applied a power law area-frequency function to an aerial photograph time series spanning the watershed's natural climate variation range (1960 to present) to estimate historic wetland loss, with historic wetland loss determined via a break in slope in the power law function. Our analysis revealed ongoing loss of small GIWs in the watershed, despite the implementation of wetland policy measures to mitigate this loss. This ongoing GIW loss is particularly detrimental as it is concomitant with a loss in the important associated ecosystem functions of these GIWs, which has serious repercussions for downstream waters. Overall, our findings support a shift in wetland policies from area to function assessments that provide governments with tools to manage the potential consequences of wetland loss in terms of increased flooding and pollution of

  17. Demonstration of wetland vegetation mapping in Florida from computer-processed satellite and aircraft multispectral scanner data

    NASA Technical Reports Server (NTRS)

    Butera, M. K.

    1979-01-01

    The success of remotely mapping wetland vegetation of the southwestern coast of Florida is examined. A computerized technique to process aircraft and LANDSAT multispectral scanner data into vegetation classification maps was used. The cost effectiveness of this mapping technique was evaluated in terms of user requirements, accuracy, and cost. Results indicate that mangrove communities are classified most cost effectively by the LANDSAT technique, with an accuracy of approximately 87 percent and with a cost of approximately 3 cent per hectare compared to $46.50 per hectare for conventional ground survey methods.

  18. Vegetation Types Alter Soil Respiration and Its Temperature Sensitivity at the Field Scale in an Estuary Wetland

    PubMed Central

    Han, Guangxuan; Xing, Qinghui; Luo, Yiqi; Rafique, Rashad; Yu, Junbao; Mikle, Nate

    2014-01-01

    Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil) in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively). During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m−2 s−1), followed by the Suaeda salsa site (0.77 µmol CO2 m−2 s−1) and the bare soil site (0.41 µmol CO2 m−2 s−1). The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland. PMID:24608636

  19. Wetland vegetation in Manzala lagoon, Nile Delta coast, Egypt: Rapid responses of pollen to altered nile hydrology and land use

    USGS Publications Warehouse

    Bernhardt, C.E.; Stanley, J.-D.; Horton, B.P.

    2011-01-01

    The pollen record in a sediment core from Manzala lagoon on the Nile delta coastal margin of Egypt, deposited from ca. AD 1860 to 1990, indicates rapid coastal wetland vegetation responses to two primary periods of human activity. These are associated with artificially altered Nile hydrologic regimes in proximal areas and distal sectors located to ???1200 km south of Manzala. Freshwater wetland plants that were dominant, such as Typha and Phragmites, decreased rapidly, whereas in the early 1900s, brackish water wetland species (e.g., Amaranthaceae) increased. This change occurred after closure of the Aswan Low Dam in 1902. The second major modification in the pollen record occurred in the early 1970s, after Aswan High Dam closure from 1965 to 1970, when Typha pollen abundance increased rapidly. Massive population growth occurred along the Nile during the 130 years represented by the core section. During this time, the total volume of lagoon water decreased because of conversion of wetland areas to agricultural land, and input of organic-rich sediment, sewage (municipal, agricultural, industrial), and fertilizer in Manzala lagoon increased markedly. Although the wetland plant community has continued to respond to increasingly intensified and varied human-induced pressures in proximal sectors, the two most marked changes in Manzala pollen best correlate with distal events (i.e., closure of the two dams at Aswan). The study also shows that the two major vegetation changes in Manzala lagoon each occurred less than 10 years after closure upriver of the Low and High dams that markedly altered the Nile regime from Upper Egypt to the coast. ?? 2011, the Coastal Education & Research Foundation (CERF).

  20. Hydrology, vegetation, and soils of four north Florida River flood plains with an evaluation of state and federal wetland determinations

    USGS Publications Warehouse

    Light, H.M.; Darst, M.R.; MacLaughlin, M.T.; Sprecher, S.W.

    1993-01-01

    A study of hydrologic conditions, vegetation, and soils was made in wetland forests of four north Florida streams from 1987 to 1990. The study was conducted by the U.S. Geological Survey in cooperation with the Florida Department of Environmental Regulation to support State and Federal efforts to improve wetland delineation methodology in flood plains. Plant communities and soils were described and related to topographic position and long-term hydrologic conditions at 10 study plots located on 4 streams. Detailed appendixes give average duration, frequency, and depth of flooding; canopy, subcanopy, and ground-cover vegetation; and taxonomic classification, series, and profile descriptions of soils for each plot. Topographic relief, range in stage, and depth of flooding were greatest on the alluvial flood plain of the Ochlockonee River, the largest of the four streams. Soils were silty in the lower elevations of the flood plain, and tree communities were distinctly different in each topographic zone. The Aucilla River flood plain was dominated by levees and terraces with very few depressions or low backwater areas. Oaks dominated the canopy of both lower and upper terraces of the Aucilla flood plain. Telogia Creek is a blackwater stream that is a major tributary of the Ochlockonee River. Its low, wet flood plain was dominated by Wyssa ogeche (Ogeechee tupelo) trees, had soils with mucky horizons, and was inundated by frequent floods of very short duration. The St. Marks River, a spring-fed stream with high base flow, had the least topographic relief and lowest range in stage of the four streams. St. Marks soils had a higher clay content than the other streams, and limestone bedrock was relatively close to the surface. Wetland determinations of the study plots based on State and Federal regulatory criteria were evaluated. Most State and Federal wetland determinations are based primarily on vegetation and soil characteristics because hydrologic records are usually not

  1. Isolated Spring Wetlands in the Great Basin and Mojave Deserts, USA: Potential Response of Vegetation to Groundwater Withdrawal

    NASA Astrophysics Data System (ADS)

    Patten, Duncan T.; Rouse, Leigh; Stromberg, Juliet C.

    2008-03-01

    Desert springs, often the sole sources of water for wildlife and cattle, support wetland and wetland/upland transition ecosystems including rare and endemic species. In the basin and range province in Nevada, USA, springs in the Great Basin and Mojave deserts are sustained by interconnected deep carbonate and shallow basin-fill aquifers which are threatened by proposed groundwater withdrawal to sustain rapidly expanding urban areas, a common problem in arid regions worldwide. This paper draws on historic groundwater data, groundwater modeling, and studies of environmental controls of spring ecosystems to speculate on the potential effects of groundwater withdrawal and water table decline on spring-supported vegetation. The focus is on springs in the Great Basin and Mojave deserts representative of those that may be affected by future, planned groundwater withdrawal. Groundwater withdrawal is expected to reduce spring discharge directly through reduced flows from the shallow basin-fill aquifer or through reduction of the hydraulic head of the deep carbonate aquifer. This flow reduction will truncate the outflow stream, reducing the areal cover of wetland and wetland/upland transition vegetation. Lowering the local water table may also reduce the amount of upland phreatophytic vegetation by causing water levels to drop below plant rooting depths. Percolation of salts to surface soils may be reduced, eventually altering desert shrub cover from halophytes to nonhalophytes. The extent of these effects will vary among springs, based on their distance from extraction sites and location relative to regional groundwater flow paths. On-site monitoring of biotic variables (including cover of selected hygrophytes and phreatophytes) should be a necessary complement to the planned monitoring of local hydrologic conditions.

  2. Isolated spring wetlands in the Great Basin and Mojave deserts, USA: potential response of vegetation to groundwater withdrawal.

    PubMed

    Patten, Duncan T; Rouse, Leigh; Stromberg, Juliet C

    2008-03-01

    Desert springs, often the sole sources of water for wildlife and cattle, support wetland and wetland/upland transition ecosystems including rare and endemic species. In the basin and range province in Nevada, USA, springs in the Great Basin and Mojave deserts are sustained by interconnected deep carbonate and shallow basin-fill aquifers which are threatened by proposed groundwater withdrawal to sustain rapidly expanding urban areas, a common problem in arid regions worldwide. This paper draws on historic groundwater data, groundwater modeling, and studies of environmental controls of spring ecosystems to speculate on the potential effects of groundwater withdrawal and water table decline on spring-supported vegetation. The focus is on springs in the Great Basin and Mojave deserts representative of those that may be affected by future, planned groundwater withdrawal. Groundwater withdrawal is expected to reduce spring discharge directly through reduced flows from the shallow basin-fill aquifer or through reduction of the hydraulic head of the deep carbonate aquifer. This flow reduction will truncate the outflow stream, reducing the areal cover of wetland and wetland/upland transition vegetation. Lowering the local water table may also reduce the amount of upland phreatophytic vegetation by causing water levels to drop below plant rooting depths. Percolation of salts to surface soils may be reduced, eventually altering desert shrub cover from halophytes to nonhalophytes. The extent of these effects will vary among springs, based on their distance from extraction sites and location relative to regional groundwater flow paths. On-site monitoring of biotic variables (including cover of selected hygrophytes and phreatophytes) should be a necessary complement to the planned monitoring of local hydrologic conditions. PMID:18060450

  3. Relationships among vegetation, geomorphology and hydrology in the Bananal Island tropical wetlands, Araguaia River basin, Central Brazil

    NASA Astrophysics Data System (ADS)

    Valente, C. R.; Latrubesse, E. M.; Ferreira, L. G.

    2013-10-01

    The Bananal Plain spreading on the Middle Araguaia River basin in Central Brazil at the Cerrado-Amazonia ecotone is a unique system that sustains the largest seasonal wetlands of the Cerrado biome. The huge Bananal Plain is an intracratonic sedimentary basin filled with Pleistocene sediments of the Araguaia formation. Covering approximately two million hectares, the Bananal Island is a major geomorphologic feature of the Bananal plain. Fieldwork and the analysis of a temporal series of MODIS-VI and Landsat ETM images allowed us to discriminate Cerrado phyto-physiognomies on the Bananal Island. Maps of vegetation and geomorphologic units were created, and from the correlation between landforms and vegetation types we identified morpho-vegetation units. Our approach allowed us to postulate that Pleistocene landforms strongly influence, if not dominate, the distribution of vegetation units. For example, the distribution of current gallery forest is not only controlled by active floodplains, but also by alluvial belts abandoned by avulsion. Additionally, arboreal Cerrado vegetation is supported by laterite developed on the sediments of the Araguaia Formation. Some of these inactive landforms are in part modified by the present day geomorphologic processes and colonized by successional vegetation that varies from alluvial forest to Cerrado. Characterized by a very flat landscape with a hindered drainage, the muddy sediments of the Araguaia Formation and the high seasonal rainfall favor the development of regional seasonal wetlands. The Bananal plain is a key area for understanding the Quaternary climatic and biogeographic changes in tropical South America. The control exerted by relict Quaternary landforms on the current vegetation units demonstrates the strong links between geomorphologic aspects of the landscape and ecological patterns. This multidisciplinary approach provides a better understanding of the biogeographic patterns in the Cerrado-Amazon ecotone, which is

  4. Investigation of uncertainties of establishment schemes in dynamic global vegetation models

    NASA Astrophysics Data System (ADS)

    Song, Xiang; Zeng, Xiaodong

    2014-01-01

    In Dynamic Global Vegetation Models (DGVMs), the establishment of woody vegetation refers to flowering, fertilization, seed production, germination, and the growth of tree seedlings. It determines not only the population densities but also other important ecosystem structural variables. In current DGVMs, establishments of woody plant functional types (PFTs) are assumed to be either the same in the same grid cell, or largely stochastic. We investigated the uncertainties in the competition of establishment among coexisting woody PFTs from three aspects: the dependence of PFT establishments on vegetation states; background establishment; and relative establishment potentials of different PFTs. Sensitivity experiments showed that the dependence of establishment rate on the fractional coverage of a PFT favored the dominant PFT by increasing its share in establishment. While a small background establishment rate had little impact on equilibrium states of the ecosystem, it did change the timescale required for the establishment of alien species in pre-existing forest due to their disadvantage in seed competition during the early stage of invasion. Meanwhile, establishment purely from background (the scheme commonly used in current DGVMs) led to inconsistent behavior in response to the change in PFT specification (e.g., number of PFTs and their specification). Furthermore, the results also indicated that trade-off between individual growth and reproduction/colonization has significant influences on the competition of establishment. Hence, further development of establishment parameterization in DGVMs is essential in reducing the uncertainties in simulations of both ecosystem structures and successions.

  5. Gas transfer velocities for quantifying methane, oxygen and other gas fluxes through the air-water interface of wetlands with emergent vegetation

    NASA Astrophysics Data System (ADS)

    Poindexter, C.; Variano, E. A.

    2012-12-01

    Empirical models for the gas transfer velocity, k, in the ocean, lakes and rivers are fairly well established, but there are few data to predict k for wetlands. We have conducted experiments in a simulated emergent marsh in the laboratory to explore the relationship between k, wind shear and thermal convection. Now we identify the implications of these results for gas transfer in actual wetlands by (1) quantifying the range of wind conditions in emergent vegetation canopies and the range of thermal convection intensities in wetland water columns, and (2) describing the non-linear interaction of these two stirring forces over their relevant ranges in wetlands. We measured mean wind speeds and wind speed variance within the shearless region of a Schoenoplectus-Typha marsh canopy in the Sacramento-San Joaquin Delta (Northern California, USA). The mean wind speed within this region, , is significantly smaller than wind above the canopy. Based on our laboratory experiments, for calm or even average wind conditions in this emergent marsh k600 is only on the order 0.1 cm hr-1 (for neutrally or stably stratified water columns). We parameterize unstable thermal stratification and the resulting thermal convection using the heat flux through the air-water interface, q. We analyzed a water temperature record for the Schoenoplectus-Typha marsh to obtain a long-term heat flux record. We used these heat flux data along with short-term heat flux data from other wetlands in the literature to identify the range of the gas transfer velocity associated with thermal convection in wetlands. The typical range of heat fluxes through water columns shaded by closed emergent canopies (-200 W m-2 to +200 W m-2) yields k600 values of 0.5 - 2.5 cm hr-1 according to the model we developed in the laboratory. Thus for calm or average wind conditions, the gas transfer velocity associated with thermal convection is significantly larger than the gas transfer velocity associated with wind

  6. Independent Wetland Vegetation Response to Climate Variability and Anthropogenic Hydrologic Control, Everglades, FL, USA

    NASA Astrophysics Data System (ADS)

    Bernhardt, C. E.; Willard, D. A.

    2007-12-01

    The response of a wetland landscape composed of multiple, distinct, plant communities to a single stimulus, whether it results from natural climate variability or human alterations, should not be assumed to be uniform across the entire landscape. The Florida Everglades is such a landscape where elevated sawgrass ridges are immediately next to water lily dominated sloughs, known collectively as the sawgrass ridge and slough landscape (SRS). The distribution of the Everglades individual sawgrass ridge and slough plant communities within the SRS was altered by 20th century construction of water control structures (canals, levees, and dikes) and alteration of the natural hydrologic regime. Although restoration planning to stabilize the remaining ridge and slough habitats is underway, little is known about the landscape's origin and response to past hydrologic changes. Analysis of pollen assemblages from transects of piston cores collected across SRS indicate that sawgrass ridges and sloughs have been vegetationally distinct from one another since the mid Holocene. Modern sawgrass ridges formed from a marsh-like environment, whereas slough communities occupied their present sites throughout the history of the sites. Ridge formation was triggered by intervals of drier climate (i.e., the Medieval Warm Period and Little Ice Age) and changes in the mean position of the Intertropical Convergence Zone. The sloughs are temporarily composed of more marsh plants during drier conditions, but quickly return to their original state when precipitation increases. During the 20th century, sloughs appear to be strongly influenced by North Atlantic Oscillation (NAO) variability in spite of water management practices, while the sawgrass ridges respond primarily to [water management] anthropogenic changes in hydrology. Our evidence that, the sawgrass ridge and slough landscape communities can act independent of one another to changes in hydrology, indicates that restoring the pre-20th

  7. Physical and Vegetative Characteristics of a Newly Constructed Wetland and Modified Stream Reach, Tredyffrin Township, Chester County, Pennsylvania, 2000-2006

    USGS Publications Warehouse

    Chaplin, Jeffrey J.; White, Kirk E.; Olson, Leif E.

    2009-01-01

    To compensate for authorized disturbance of naturally occurring wetlands and streams during roadway improvements to U.S. Highway 202 in Chester and Montgomery Counties, Pa., the Pennsylvania Department of Transportation (PennDOT) constructed 0.42 acre of emergent wetland and 0.94 acre of scrub-shrub/forested wetland and modified sections of a 1,600-foot reach of Valley Creek with woody riparian plantings and streambank-stabilization structures (including rock deflectors). In accordance with project permits and additional guidance issued by the U.S. Army Corps of Engineers, the U.S. Geological Survey (USGS), in cooperation with PennDOT, collected data from 2000 through 2006 to quantify changes in 1) the vegetation, soils, and extent of emergent and scrub-shrub/forested parts of the constructed wetland, 2) the profile, dimension, and substrate in the vicinity of rock deflectors placed at two locations within the modified stream reach, and 3) the woody vegetation within the planted riparian buffer. The data for this investigation were collected using an approach adapted from previous investigations so that technology and findings may be more easily transferred among projects with similar objectives. Areal cover by planted and non-planted vegetation growing within the emergent and scrub-shrub/forested parts of the constructed wetland exceeded 85 percent at the end of each growing season, a criterion in special condition 25c in the U.S. Army Corps of Engineers project permit. Areal cover of vegetation in emergent and scrub-shrub/forested parts of the constructed wetland exceeded 100 percent in all but one growing season. Frequent and long-lasting soil saturation favored obligate-wetland species like Typha latifolia (broadleaf cattail) and Scirpus validus (great bulrush), both of which maintained dominance in the emergent wetland throughout the study (percent cover was 20 and 78 percent, respectively, in 2006). Echinocloa crusgalli (barnyard grass), an annual invasive

  8. Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China.

    PubMed

    Lou, Yanjing; Pan, Yanwen; Gao, Chuanyu; Jiang, Ming; Lu, Xianguo; Xu, Y Jun

    2016-01-01

    Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region. PMID:27097325

  9. Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China

    PubMed Central

    Lou, Yanjing; Pan, Yanwen; Gao, Chuanyu; Jiang, Ming; Lu, Xianguo; Xu, Y. Jun

    2016-01-01

    Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region. PMID:27097325

  10. Mercury cycling in agricultural and managed wetlands of California: seasonal influences of vegetation on mercury methylation, storage, and transport

    USGS Publications Warehouse

    Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark C.; Kakouros, Evangelos; Agee, Jennifer L.; Kieu, Le H.; Stricker, Craig A.; Fleck, Jacob A.; Ackerman, Joshua T.

    2013-01-01

    Plants are a dominant biologic and physical component of many wetland capable of influencing the internal pools and fluxes of methylmercury (MeHg). To investigate their role with respect to the latter, we examined the changing seasonal roles of vegetation biomass and Hg, C and N composition from May 2007-February 2008 in 3 types of agricultural wetlands (domesticated or white rice, wild rice, and fallow fields), and in adjacent managed natural wetlands dominated by cattail and bulrush (tule). We also determined the impact of vegetation on seasonal microbial Hg methylation rates, and Hg and MeHg export via seasonal storage in vegetation, and biotic consumption of rice seed. Despite a compressed growing season of ~ 3 months, annual net primary productivity (NPP) was greatest in white rice fields and carbon more labile (leaf median C:N ratio = 27). Decay of senescent litter (residue) was correlated with microbial MeHg production in winter among all wetlands. As agricultural biomass accumulated from July to August, THg concentrations declined in leaves but MeHg concentrations remained consistent, such that MeHg pools generally increased with growth. Vegetation provided a small, temporary, but significant storage term for MeHg in agricultural fields when compared with hydrologic export. White rice and wild rice seeds reached mean MeHg concentrations of 4.1 and 6.2 ng gdw- 1, respectively. In white rice and wild rice fields, seed MeHg concentrations were correlated with root MeHg concentrations (r = 0.90, p < 0.001), suggesting transport of MeHg to seeds from belowground tissues. Given the proportionally elevated concentrations of MeHg in rice seeds, white and wild rice crops may act as a conduit of MeHg into biota, especially waterfowl which forage heavily on rice seeds within the Central Valley of California, USA. Thus, while plant tissues and rhizosphere soils provide temporary storage for MeHg during the growing season, export of MeHg is enhanced post-harvest through

  11. Physical and vegetative characteristics of a relocated stream reach, constructed wetland, and riparian buffer, Upper Saucon Township, Lehigh County, Pennsylvania, 2000-04

    USGS Publications Warehouse

    Chaplin, Jeffrey J.; White, Kirk E.; Loper, Connie A.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the Pennsylvania Department of Transportation, Engineering District 5-0, investigated physical and vegetative changes within a relocated stream reach, constructed wetland, and riparian buffer from September 2000 to October 2004. This report presents an evaluation of data collected using methods from multiple sources that have been adapted into a consistent approach. This approach is intended to satisfy a need for consistent collection of different types of data with the goal of transferring technology and findings to similar projects. Survey data indicate that adjustment of the upstream part of the relocated stream reach slowed over the monitoring period, but the downstream channel remains unstable as evidenced by excessive deposition. Upstream migration of a nick point has slowed or stopped altogether as of the 2003 assessment when this feature came in contact with the upstream-most part of the channel that is lined with riprap. Documented streambed erosion in the upstream cross sections, along with deposition downstream, has resulted in an overall decrease in slope of the stream channel over the monitoring period. Most streambed erosion took place prior to the 2002 assessment when annual mean streamflows were less than those in the final 2 years of monitoring. An abundance of fine sediment dominates the substrate of the relocated channel. Annual fluctuations of large particles within each cross section demonstrates the capacity of the relocated channel to transport the entire range of sediment. The substrate within the 0.28-acre constructed wetland (a mixture of soil from an off-site naturally occurring wetland and woodchips) supported a hydrophytic-vegetation community throughout the investigation. Eleocharis obtusa (spike rush), an obligate-wetland herb, was the most prevalent species, having a maximum areal cover of 90 percent in fall 2001 and a minimum of 23 percent in fall 2004. Drought-like conditions in water

  12. Landscape object-based analysis of wetland plant functional types: the effects of spatial scale, vegetation classes and classifier methods

    NASA Astrophysics Data System (ADS)

    Dronova, I.; Gong, P.; Wang, L.; Clinton, N.; Fu, W.; Qi, S.

    2011-12-01

    Remote sensing-based vegetation classifications representing plant function such as photosynthesis and productivity are challenging in wetlands with complex cover and difficult field access. Recent advances in object-based image analysis (OBIA) and machine-learning algorithms offer new classification tools; however, few comparisons of different algorithms and spatial scales have been discussed to date. We applied OBIA to delineate wetland plant functional types (PFTs) for Poyang Lake, the largest freshwater lake in China and Ramsar wetland conservation site, from 30-m Landsat TM scene at the peak of spring growing season. We targeted major PFTs (C3 grasses, C3 forbs and different types of C4 grasses and aquatic vegetation) that are both key players in system's biogeochemical cycles and critical providers of waterbird habitat. Classification results were compared among: a) several object segmentation scales (with average object sizes 900-9000 m2); b) several families of statistical classifiers (including Bayesian, Logistic, Neural Network, Decision Trees and Support Vector Machines) and c) two hierarchical levels of vegetation classification, a generalized 3-class set and more detailed 6-class set. We found that classification benefited from object-based approach which allowed including object shape, texture and context descriptors in classification. While a number of classifiers achieved high accuracy at the finest pixel-equivalent segmentation scale, the highest accuracies and best agreement among algorithms occurred at coarser object scales. No single classifier was consistently superior across all scales, although selected algorithms of Neural Network, Logistic and K-Nearest Neighbors families frequently provided the best discrimination of classes at different scales. The choice of vegetation categories also affected classification accuracy. The 6-class set allowed for higher individual class accuracies but lower overall accuracies than the 3-class set because

  13. Control of reed canarygrass promotes wetland herb and tree seedling establishment in an upper Mississippi River Floodplain forest

    USGS Publications Warehouse

    Thomsen, Meredith; Brownell, Kurt; Groshek, Matthew; Kirsch, Eileen

    2012-01-01

    Phalaris arundinacea (reed canarygrass) is recognized as a problematic invader of North American marshes, decreasing biodiversity and persisting in the face of control efforts. Less is known about its ecology or management in forested wetlands, providing an opportunity to apply information about factors critical to an invader's control in one wetland type to another. In a potted plant experiment and in the field, we documented strong competitive effects of reed canarygrass on the establishment and early growth of tree seedlings. In the field, we demonstrated the effectiveness of a novel restoration strategy, combining site scarification with late fall applications of pre-emergent herbicides. Treatments delayed reed canarygrass emergence the following spring, creating a window of opportunity for the early growth of native plants in the absence of competition from the grass. They also allowed for follow-up herbicide treatments during the growing season. We documented greater establishment of wetland herbs and tree seedlings in treated areas. Data from small exclosures suggest, however, that deer browsing can limit tree seedling height growth in floodplain restorations. Slower tree growth will delay canopy closure, potentially allowing reed canarygrass re-invasion. Thus, it may be necessary to protect tree seedlings from herbivory to assure forest regeneration.

  14. Exploring the response of West Siberian wetland methane emissions to potential future changes in climate, vegetation, and soil microbial metabolism

    NASA Astrophysics Data System (ADS)

    Bohn, Theodore; Kaplan, Jed; Lettenmaier, Dennis

    2015-04-01

    Methane emissions from northern peatlands depend strongly on environmental conditions, wetland plant species assemblages (via root zone oxidation and plant-aided transport), and soil microbial behavior (via metabolic pathways). While the responses of wetland methane emissions to potential future climate change have been extensively explored, the effects of future changes in plant species and soil microbial metabolism are not as well studied. We ran the Variable Infiltration Capacity (VIC) land surface model over the West Siberian Lowland (WSL), with methane emissions parameters that vary spatially with dominant plant species, and forced with outputs from 32 CMIP5 models for the RCP4.5 scenario. We compared the effects of changes in climate and vegetation (in terms of both leaf area index and species abundances) on predicted wetland CH4 emissions for the period 2071-2100, relative to the period 1981-2010. We also explored possible acclimatization of soil microbial communities to these changes. We evaluated the effects of climate change, potential northward migration of plant species, and potential microbial acclimatization on end-of-century methane emissions over the WSL, in terms of both total annual emissions and the spatial distribution of emissions. Our results suggest that, while microbial acclimatization mitigates the effects of warmer temperatures, the northward migration of plant species enhances the response to warming (due to plant-aided transport), and additionally shifts the location of maximal emissions northward, where the possible release of ancient carbon with permafrost thaw is a concern. Our work indicates the importance of better constraining the responses of wetland plants and soil microbial communities to changes in climate as they are critical determinants of the region's future methane emissions.

  15. FLUE GAS DESULFURIZATION SLUDGE: ESTABLISHMENT OF VEGETATION ON PONDED AND SOIL-APPLIED WASTE

    EPA Science Inventory

    The report gives results of research to identify and evaluate forms of vegetation and methods of their establishment for reclaiming retired flue gas desulfurization sludge ponds. Also studied were the soil liming value of limestone scrubber sludge (LSS) and plant uptake and perco...

  16. Gas exchange in wetlands with emergent vegetation: The effects of wind and thermal convection at the air-water interface

    NASA Astrophysics Data System (ADS)

    Poindexter, Cristina M.; Variano, Evan A.

    2013-07-01

    Methane, carbon dioxide, and oxygen are exchanged between wetlands and the atmosphere through multiple pathways. One of these pathways, the hydrodynamic transport of dissolved gas through the surface water, is often underestimated in importance. We constructed a model wetland in the laboratory with artificial emergent plants to investigate the mechanisms and magnitude of this transport. We measured gas transfer velocities, which characterize the near-surface stirring driving air-water gas transfer, while varying two stirring processes important to gas exchange in other aquatic environments: wind and thermal convection. To isolate the effects of thermal convection, we identified a semiempirical model for the gas transfer velocity as a function of surface heat loss. The laboratory results indicate that thermal convection will be the dominant mechanism of air-water gas exchange in marshes with emergent vegetation. Thermal convection yielded peak gas transfer velocities of 1 cm h-1. Because of the sheltering of the water surface by emergent vegetation, gas transfer velocities for wind-driven stirring alone are likely to exceed this value only in extreme cases.

  17. Camera derived vegetation greenness index as proxy for gross primary production in a low Arctic wetland area

    NASA Astrophysics Data System (ADS)

    Westergaard-Nielsen, Andreas; Lund, Magnus; Hansen, Birger Ulf; Tamstorf, Mikkel Peter

    2013-12-01

    The Arctic is experiencing disproportionate warming relative to the global average, and the Arctic ecosystems are as a result undergoing considerable changes. Continued monitoring of ecosystem productivity and phenology across temporal and spatial scales is a central part of assessing the magnitude of these changes. This study investigates the ability to use automatic digital camera images (DCIs) as proxy data for gross primary production (GPP) in a complex low Arctic wetland site. Vegetation greenness computed from DCIs was found to correlate significantly (R2 = 0.62, p < 0.001) with a normalized difference vegetation index (NDVI) product derived from the WorldView-2 satellite. An object-based classification based on a bi-temporal image composite was used to classify the study area into heath, copse, fen, and bedrock. Temporal evolution of vegetation greenness was evaluated and modeled with double sigmoid functions for each plant community. GPP at light saturation modeled from eddy covariance (EC) flux measurements were found to correlate significantly with vegetation greenness for all plant communities in the studied year (i.e., 2010), and the highest correlation was found between modeled fen greenness and GPP (R2 = 0.85, p < 0.001). Finally, greenness computed within modeled EC footprints were used to evaluate the influence of individual plant communities on the flux measurements. The study concludes that digital cameras may be used as a cost-effective proxy for potential GPP in remote Arctic regions.

  18. Evaluating the effect of rainfall variability on vegetation establishment in a semidesert grassland.

    PubMed

    Fehmi, Jeffrey S; Niu, Guo-Yue; Scott, Russell L; Mathias, Andrea

    2014-01-01

    Of the operations required for reclamation in arid and semi-arid regions, establishing vegetation entails the most uncertainty due to reliance on unpredictable rainfall for seed germination and seedling establishment. The frequency of successful vegetation establishment was estimated based on a land surface model driven by hourly atmospheric forcing data, 7 years of eddy-flux data, and 31 years of rainfall data at two adjacent sites in southern Arizona, USA. Two scenarios differing in the required imbibition time for successful germination were evaluated-2 or 3 days availability of sufficient surface moisture. Establishment success was assumed to occur if plants could germinate and if the drying front in the soil did not overtake the growth of seminal roots. Based on our results, vegetation establishment could be expected to fail in 32 % of years. In the worst 10-year span, six of ten plantings would have failed. In the best 10-year span, only one of ten was projected to fail. Across all assessments, at most 3 years in a row failed and 6 years in a row were successful. Funding for reclamation seeding must be available to allow reseeding the following year if sufficient amount and timing of rainfall does not occur. PMID:23974536

  19. 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

  20. The backscattering characteristics of wetland vegetation and water-level changes detection using multi-mode SAR: A case study

    NASA Astrophysics Data System (ADS)

    Zhang, Meimei; Li, Zhen; Tian, Bangsen; Zhou, Jianmin; Tang, Panpan

    2016-03-01

    A full understanding of the backscattering characteristics of wetlands is necessary for the analysis of the hydrological conditions. In this study, a temporal set of synthetic aperture radar (SAR) imagery, acquired at different frequencies, polarizations and incidence angles over the coastal wetlands of the Liaohe River Delta, China, were used to characterize seasonal variations in radar backscattering coefficient for reed marshes and rice fields. The combination of SAR backscattering intensity and an optical-based normalized difference vegetation index (NDVI) for long time series can provide additional insight into vegetation structural and its hydrological states. After identifying the factors that induce the backscattering and scattering mechanism changes, detailed analysis of L-band ALOS PALSAR interferometric SAR (InSAR) imagery was conducted to study water-level changes under different environmental conditions. In addition, ENVISAT altimetry was used to validate the accuracy of the water-level changes estimated using the InSAR technique-this is an effective tool instead of sparsely distributed gauge stations for the validation. Our study demonstrates that L-band SAR data with horizontal polarization is particularly suitable for the extraction of water-level changes in the study area; however, vertically-polarized C-band data may also be useful where the density of herbaceous vegetation is low at the initial stage. It is also shown that integrated analysis of the backscattering mechanism and interferometric characteristics using multi-mode SAR can considerably enhance the reliability of the water-level retrieval scheme and better capture the spatial distribution of hydrological patterns.

  1. Vegetation dynamics of restored and remnant Willamette Valley, OR wet prairie wetlands

    EPA Science Inventory

    Wet prairie wetlands are now one of the rarest habitat types in the Willamette Valley of Oregon, USA. Less than two percent of their historic extent remains, with most having been converted into agricultural fields (Christy and Alverson 2011, ONHP 1983). This habitat is the obl...

  2. The Role of Hydropedologic Vegetation Zones in Greenhouse Gas Emissions for Agricultural Wetland Landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Net greenhouse gas (GHG) source strength for agricultural wetland ecosystems in the Prairie Pothole Region (PPR) and spatial constraints associated with CH4, CO2, and N2O fluxes are currently unknown. Greenhouse gas fluxes typically vary with edaphic, hydrologic, biologic, and climatic factors. In...

  3. Developing a National Vegetation Multimetric Metric Index of Wetland Condition for the Conterminous United States

    EPA Science Inventory

    This product is an abstract for the 2015 Ecological Society Meeting in Baltimore, Maryland in August. The U.S. Environmental Protection Agency (USEPA), with states, tribes, and other partners, conducted the first-ever National Wetland Condition Assessment (NWCA) in 2011, using a...

  4. Pulsed Discharge Through Wetland Vegetation as a Control on Bed Shear Stress and Sediment Transport Affecting Everglades Restoration

    NASA Astrophysics Data System (ADS)

    Larsen, L. E.; Harvey, J. W.; Crimaldi, J. P.

    2007-12-01

    depth is not likely to increase water velocity and entrainment, it is necessary instead that restoration focus on increasing energy slope as a means to entrain sediment within sloughs and redistribute it to ridges. Surface-water gravity waves caused by hurricanes or pulsed releases of water from impounded areas may be the most effective mechanism for achieving sediment redistribution in the Everglades and other wetland and riparian environments with abundant emergent vegetation.

  5. Responses of Hyalella azteca to a Pesticide-Nutrient Mixture in Vegetated and Non-vegetated Wetland Mesocosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic vegetation has been shown to improve water quality by trapping and processing contaminants such as pesticides, nutrients and sediments. Currently there is little information regarding effects of pesticide and nutrient mixtures on aquatic biota in these systems and the influence aquatic vege...

  6. Development and testing of an index of biotic integrity based on submersed and floating vegetation and its application to assess reclamation wetlands in Alberta's oil sands area, Canada.

    PubMed

    Rooney, Rebecca C; Bayley, Suzanne E

    2012-01-01

    We developed and tested a plant-based index of biological integrity (IBI) and used it to evaluate the existing reclamation wetlands in Alberta's oil sands mining region. Reclamation plans call for >15,000 ha of wetlands to be constructed, but currently, only about 25 wetlands are of suitable age for evaluation. Reclamation wetlands are typically of the shallow open water type and range from fresh to sub-saline. Tailings-contaminated wetlands in particular may have problems with hydrocarbon- and salt-related toxicity. From 60 initial candidate metrics in the submersed aquatic and floating vegetation communities, we selected five to quantify biological integrity. The IBI included two diversity-based metrics: the species richness of floating vegetation and the percent of total richness contributed by Potamogeton spp. It also included three relative abundance-based metrics: that of Ceratophyllum demersum, of floating leafed species and of alkali-tolerant species. We evaluated the contribution of nonlinear metrics to IBI performance but concluded that the correlation between IBI scores and wetland condition was not improved. The method used to score metrics had an influence on the IBI sensitivity. We conclude that continuous scoring relative to the distribution of values found in reference sites was superior. This scoring approach provided good sensitivity and resolution and was grounded in reference condition theory. Based on these IBI scores, both tailings-contaminated and tailings-free reclamation wetlands have significantly lower average biological integrity than reference wetlands (ANOVA: F(2,59) = 34.7, p = 0.000000000107). PMID:21484300

  7. Multisite comparison of drivers of methane emissions from wetlands in the European Arctic: influence of vegetation community and water table.

    NASA Astrophysics Data System (ADS)

    Dinsmore, Kerry; Drewer, Julia; Leeson, Sarah; Skiba, Ute; Levy, Pete; George, Charles

    2014-05-01

    Arctic and sub arctic wetlands are a major source of atmospheric CH4 and therefore have the potential to be important in controlling global radiative forcing. Furthermore, the strong links between wetland CH4 emissions and vegetation community, hydrology and temperature suggest potentially large feedbacks between climate change and future emissions. Quantifying current emissions over large spatial scales and predicting future climatic feedbacks requires a fundamental understanding of the ground based drivers of plot scale emissions. The MAMM project (Methane in the Arctic: Measurements and Modelling) aims to understand and quantify current CH4 emissions and future climatic impacts by combining both ground and aircraft measurements across the European Arctic with regional computer modelling. Here we present results from the ground-based MAMM measurement campaigns, analysing chamber-measured CH4 emissions from two sites in the European Arctic/Sub-Arctic region (Sodankylä, Finland; Stordalen Mire, Sweden) from growing seasons in 2012 and 2013. A total of 85 wetland static chambers were deployed across the two field sites; 39 at Sodankylä (67° 22'01' N, 26° 3'06' E) in 2012 and 46 at Stordalen Mire (68° 21'20' N, 19° 02'56' E) in 2013. Chamber design, protocol and deployment were the same across both sites. Chambers were located at sites chosen strategically to cover the local range of water table depths and vegetation communities. A total of 18 and 15 repeated measurements were made at each chamber in Sodankylä and Stordalen Mire, respectively, over the snow-free season. Preliminary results show a large range of CH4 fluxes across both sites ranging from a CH4 uptake of up to 0.07 and 0.06 mg CH4-C m-2 hr-1 to emissions of 17.3 and 44.2 mg CH4-C m-2 hr-1 in Sodankylä and Stordalen Mire, respectively. Empirical models based on vegetation community, water table depth, temperature and soil nutrient availability (Plant Root Simulator Probes, PRSTM) have been

  8. Comparison of phosphorus fractions and phosphatase activities in coastal wetland soils along vegetation zones of Yancheng National Nature Reserve, China

    NASA Astrophysics Data System (ADS)

    Huang, Lidong; Zhang, Yaohong; Shi, Yiming; Liu, Yibo; Wang, Lin; Yan, Ning

    2015-05-01

    Phosphorus (P) fractions and phosphatase activities were measured in 22 coastal wetland soils with typical vegetation successions in Yancheng National Nature Reserve, China. P forms and phosphatase activities varied greatly from site to site even under the same vegetation cover. NH4Cl-P, bicarbonate/dithionite extracted P and NaOH-P were remarkably higher (p < 0.05) in soils with exotic invasive plants, Spartina alterniflora, than in soils with the native species Suaeda salsa, Scirpus mariquete and Phragmites australis. HCl-P and refractory P showed little variation. No significant differences were detected for either alkaline phosphatase (ALAP) or acid phosphatase (ACAP) among the soils. All of the above properties were much higher in soils with plant growth compared to bare flat soils. Regression analysis demonstrated that organic matter (OM), Al, Ca, Fe and total P (TP) were able to explain more than 70% of the variations in the P fractions (except 29% of NH4Cl-P), and OM was the most important contributing factor. ALAP and ACAP were irrelevant to P but were significantly related to TOC, suggesting that carbon was a limiting factor for P mineralization in this area. Owing to its huge biomass and densities, Spartina alterniflora displayed great potential for carbon input, thus facilitating P mineralization and cycling. The results enhance our understanding of P availability differences in this area covered by invasive and native vegetation.

  9. Trace element-induced stress in freshwater wetland vegetation: Preliminary results

    NASA Technical Reports Server (NTRS)

    Wood, B. L.; Beck, L. H.

    1986-01-01

    Airborne Imaging Spectrometer (AIS) data were acquired over an area of freshwater wetlands in Central California on September 23, 1985. Plant samples were subsequently collected along the flight line with the goal of relating plant tissue chemistry to spectral reflectance in the near-infrared region. It was determined that a consistent relationship existed between spectral response and plant tissue chemistry. This was especially evident in the 1500 to 1700 nm region.

  10. Evaluating the influence of wetland vegetation on chemical residence time in Mississippi Delta drainage ditches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of emergent vegetation within channelized aquatic environments has the capacity to provide a number of biological functions as well as alter the hydrology of the system. Vegetation within the channel exerts roughness, drag and friction on flowing water, reducing flow rates, increasing w...

  11. Gradient Analysis and Classification of Carolina Bay Vegetation: A Framework for Bay Wetlands Conservation and Restoration

    SciTech Connect

    Diane De Steven,Ph.D.; Maureen Tone,PhD.

    1997-10-01

    This report address four project objectives: (1) Gradient model of Carolina bay vegetation on the SRS--The authors use ordination analyses to identify environmental and landscape factors that are correlated with vegetation composition. Significant factors can provide a framework for site-based conservation of existing diversity, and they may also be useful site predictors for potential vegetation in bay restorations. (2) Regional analysis of Carolina bay vegetation diversity--They expand the ordination analyses to assess the degree to which SRS bays encompass the range of vegetation diversity found in the regional landscape of South Carolina's western Upper Coastal Plain. Such comparisons can indicate floristic status relative to regional potentials and identify missing species or community elements that might be re-introduced or restored. (3) Classification of vegetation communities in Upper Coastal Plain bays--They use cluster analysis to identify plant community-types at the regional scale, and explore how this classification may be functional with respect to significant environmental and landscape factors. An environmentally-based classification at the whole-bay level can provide a system of templates for managing bays as individual units and for restoring bays to desired plant communities. (4) Qualitative model for bay vegetation dynamics--They analyze present-day vegetation in relation to historic land uses and disturbances. The distinctive history of SRS bays provides the possibility of assessing pathways of post-disturbance succession. They attempt to develop a coarse-scale model of vegetation shifts in response to changing site factors; such qualitative models can provide a basis for suggesting management interventions that may be needed to maintain desired vegetation in protected or restored bays.

  12. Coastal vegetation invasion increases greenhouse gas emission from wetland soils but also increases soil carbon accumulation.

    PubMed

    Chen, Yaping; Chen, Guangcheng; Ye, Yong

    2015-09-01

    Soil properties and soil-atmosphere fluxes of CO2, CH4 and N2O from four coastal wetlands were studied throughout the year, namely, native Kandelia obovata mangrove forest vs. exotic Sonneratia apetala mangrove forest, and native Cyperus malaccensis salt marsh vs. exotic Spartina alterniflora salt marsh. Soils of the four wetlands were all net sources of greenhouse gases while Sonneratia forest contributed the most with a total soil-atmosphere CO2-equivalent flux of 137.27 mg CO2 m(-2) h(-1), which is 69.23%, 99.75% and 44.56% higher than that of Kandelia, Cyperus and Spartina, respectively. The high underground biomass and distinctive root structure of Sonneratia might be responsible for its high greenhouse gas emission from the soil. Soils in Spartina marsh emitted the second largest amount of total greenhouse gases but it ranked first in emitting trace greenhouse gases. Annual average CH4 and N2O fluxes from Spartina soil were 13.77 and 1.14 μmol m(-2) h(-1), respectively, which are 2.08 and 1.46 times that of Kandelia, 1.03 and 1.15 times of Sonneratia, and 1.74 and 1.02 times of Cyperus, respectively. Spartina has longer growing season and higher productivity than native marshes which might increase greenhouse gas emission in cold seasons. Exotic wetland soils had higher carbon stock as compared to their respective native counterparts but their carbon stocks were offset by a larger proportion because of their higher greenhouse gas emissions. Annual total soil-atmosphere fluxes of greenhouse gases reduced soil carbon burial benefits by 8.1%, 9.5%, 6.4% and 7.2% for Kandelia, Sonneratia, Cyperus and Spartina, respectively, which narrowed down the gaps in net soil carbon stock between native and exotic wetlands. The results indicated that the invasion of exotic wetland plants might convert local coastal soils into a considerable atmospheric source of greenhouse gases although they at the same time increase soil carbon accumulation. PMID:25918889

  13. Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation

    PubMed Central

    Gannon, Travis W.; Polizzotto, Matthew L.

    2014-01-01

    Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals is often not well understood. Here we demonstrate an integrated field lysimetry and porewater sampling method for evaluating the mobility of chemicals applied to soils and established vegetation. Lysimeters, open columns made of metal or plastic, are driven into bareground or vegetated soils. Porewater samplers, which are commercially available and use vacuum to collect percolating soil water, are installed at predetermined depths within the lysimeters. At prearranged times following chemical application to experimental plots, porewater is collected, and lysimeters, containing soil and vegetation, are exhumed. By analyzing chemical concentrations in the lysimeter soil, vegetation, and porewater, downward leaching rates, soil retention capacities, and plant uptake for the chemical of interest may be quantified. Because field lysimetry and porewater sampling are conducted under natural environmental conditions and with minimal soil disturbance, derived results project real-case scenarios and provide valuable information for chemical management. As chemicals are increasingly applied to land worldwide, the described techniques may be utilized to determine whether applied chemicals pose adverse effects to human health or the environment. PMID:25045915

  14. Analysis of LANDSAT ETM and TM multi-temporal data for IPCI-based wetland vegetation condition classes in the prairie pothole region of North Dakota

    NASA Astrophysics Data System (ADS)

    Mita, Dath Kakole

    In this study, geographic information systems (GIS), FRAGSTATS (landscape pattern analysis program), and satellite classification land cover data were used to (1) explore, quantify, and compare the spatial pattern of landscapes surrounding seasonal and temporary wetlands in the Prairie Pothole Region (PPR) of North Dakota; (2) determine the relationship of landscape metrics to the Index of Plant Community Integrity (IPCI); and (3) develop a landscape-level wetland condition prediction model. Patch-based statistics, derived from multi-temporal (LANDSAT TM and ETM+) land cover data, were summarized at the class and landscape-level and used to characterize landscape spatial pattern. Non-Metric Multidimensional Scaling ordination was used to evaluate the dissimilarity in landscape metric space of wetlands of differing IPCI values. Statistical analysis confirmed differences in spatial patterns surrounding wetlands. Strong associations were also discovered between the IPCI condition of wetlands and 13 landscape metrics, largely among seasonal wetlands (landscapes with relatively minimal human disturbance). The associations were relatively weaker among temporary wetlands (landscapes subjected to repeated and considerable agricultural management). A data-driven model, the Landscape Wetland Analysis Model (LWAM), was developed and validated for rapid quantitative assessment of landscape structure, and prediction of potential wetland plant community condition. The modeling approach was based on (1) identification of metrics that displayed reasonable relationship(s) with wetland condition classes, (2) establishment of threshold levels that significantly and consistently separated the IPCI wetland conditions, and (3) the development of decision rules for obtaining wetland modeled condition class membership. Three landscape metrics were retained for model development: (1) grassland percent core area of landscape (C%LAND), (2) grassland largest patch index (LPI), and (3) the

  15. Establishment of woody riparian vegetation in relation to annual patterns of streamflow, Bill Williams River, Arizona

    USGS Publications Warehouse

    Shafroth, P.B.; Auble, G.T.; Stromberg, J.C.; Patten, D.T.

    1998-01-01

    Previous studies have revealed the close coupling of components of annual streamflow hydrographs and the germination and establishment of Populus species. Key hydrograph components include the timing and magnitude of flood peaks, the rate of decline of the recession limb, and the magnitude of base flows. In this paper, we retrospectively examine establishment of four woody riparian species along the Bill Williams River, Arizona, USA, in the context of annual patterns of streamflow for the years 1993-1995. The four species examined were the native Populus fremontii, Salix gooddingii, and Baccharis salicifolia and the exotic Tamarix ramosissima. We modeled locations suitable for germination of each species along eight study transects by combining historic discharge data, calculated stage-discharge relationships, and seed-dispersal timing observations. This germination model was a highly significant predictor of seedling establishment. Where germination was predicted to occur, we compared values of several environmental variables in quadrats where we observed successful establishment with quadrats where establishment was unsuccessful. The basal area of mature woody vegetation, the maximum annual depth to ground water, and the maximum rate of water-table decline were the variables that best discriminated between quadrats with and without seedlings. The results of this study suggest that the basic components of models that relate establishment of Populus spp. to annual patterns of streamflow may also be applicable to other woody riparian species. Reach-to-reach variation in stage-discharge relationships can influence model parameters, however, and should be considered if results such as ours are to be used in efforts to prescribe reservoir releases to promote establishment of native riparian vegetation.

  16. The influence of topography and vegetation self-organization over resource fluxes in wetland ecosystems

    NASA Astrophysics Data System (ADS)

    Stieglitz, Marc; Cheng, Yiwei; Truk, Greg; Engel, Victor; Ross, Joshua

    2014-05-01

    While it is recognized that topography and vegetation self-organization (SO) are both first order controls over ecosystem dynamics, the discrete contributions that these two controls have over ecosystem functioning have not been studied in any rigorous way. This work is focused on systematically isolating the separate and combined impacts of topography and SO over vegetation dynamics. We simulate the steady state and transient dynamics of nitrogen-limited patterned peat vegetation observed in the bogs of northern Siberia. We do so across a realistic range of land slopes, nutrient limitation values, and rainfall amounts. Simulation results show that on relatively shallow slopes, vegetation SO is a primary control over the spatial arrangement of vegetation, and that such self-organized arrangements yield the most efficient capture of ecosystem resources. However, as slope increases, and or resource limitation is low, topography begins to exert its control over the temporal and spatial dynamics. As will be discussed, these results suggest a simple continuum framework, valid across biomes, for understanding the interplay between these two first order controls. Specifically, as resources (e.g., water, nutrients) increase, ecosystem dynamics shift towards topographic control, while when resources are reduced, ecosystem dynamics shift towards vegetation SO control.

  17. Greenhouse gas emissions from constructed wetlands treating dairy wastewater

    NASA Astrophysics Data System (ADS)

    Glass, Vimy M.

    In Nova Scotia, constructed wetland systems are widely considered as effective treatment systems for agricultural wastewater. Although research has examined the water quality treatment attributes, there has been limited focus on the air quality effects of these systems. Six operational pilot-scale constructed wetlands were built with flow-through chambers for quantifying greenhouse gas (GHG) emissions in Truro, NS. Utilized within this facility were three gas analyzers to monitor GHG emissions (CO2, N 2O, CH4) and the gaseous fluxes could then be determined using the mass balance micrometeorological technique. Prior to data collection, the site underwent testing to ensure valid conclusions and replicated responses from the wetland systems. Those wetlands receiving wastewater at a typical HLR (10.6 mm d-1) and with ample vegetation displayed the best concentration reductions. During the growing season (GS), average CO 2 consumption was large (approximately -44 g CO2m -2 d-1) for wetlands with dense vegetation (approximately 100% cover) at the typical loading rate. For those wetlands at higher loading rates, CO2 emissions were observed to be as high as +9.2 g CO 2m-2 d-1. Wetlands with typical loading rates and healthy aquatic vegetation produced average CH4 fluxes of approximately 43 g CO2 eq. m-2d-1, while higher loaded systems with little vegetation approached 90 g CO 2 eq. m-2d-1. During the non-growing season (NGS), all vegetated wetlands exhibited higher CH4 emissions than the non-vegetated systems (˜15 to 20% higher). Vegetation maturity played a strong role in the GHG balance. The average CO2consumption for wetlands with established vegetation was ˜ -36 g CO2 m -2 d-1 during the GS. Wetland 4, which had been newly transplanted in 2004, had the highest single day CO2 consumption of -152 g CO2m-2 d-1 . Methane emissions from wetlands with two-year-old vegetation followed the same pattern but were approximately half of the emissions recorded from 2003. The

  18. Ground-cover vegetation in wetland forests of the lower Suwannee River floodplain, Florida, and potential impacts of flow reductions

    USGS Publications Warehouse

    Darst, Melanie R.; Light, Helen M.; Lewis, Lori J.

    2002-01-01

    Ground-cover vegetation was surveyed in wetland forests in the lower Suwannee River floodplain, Florida, in a study conducted by the U.S. Geological Survey in cooperation with the Suwannee River Water Management District from 1996 to 1999. Increased water use in the basin, supplied primarily from ground water, could reduce ground-water discharge to the river and flows in the lower Suwannee River. Many of the 282 ground-cover species found in wetland forests of the floodplain have distributions that are related to flow-dependent hydrologic characteristics of forest types, and their distributions would change if flows were reduced. Overall species diversity in the floodplain might decrease, and the composition of ground-cover vegetation in all forest types might change with flow reductions. The study area included forests within the 10-year floodplain of the lower Suwannee River from its confluence with the Santa Fe River to the lower limit of forests near the Gulf of Mexico. The floodplain is divided into three reaches (riverine, upper tidal, and lower tidal) due to variations in hydrology, vegetation, and soils with proximity to the coast. The riverine (non-tidal) reach had the greatest number of total species (203) and species unique to that reach (81). Mitchella repens, Toxicodendron radicans, and Axonopus furcatus were the most frequently dominant species in riverine bottomland hardwoods. Free-floating aquatic species, such as Spirodela punctata and Lemna valdiviana, were the dominant species in the wettest riverine swamps. The upper tidal reach had the lowest number of total species (116), only two species unique to that reach, and the lowest density of ground cover (26 percent). Panicum commutatum and Crinum americanum were frequent dominant species in upper tidal forests. The lower tidal reach had the highest ground-cover density (43 percent) and the second highest number of total species (183) and number of species unique to that reach (55). Saururus cernuus

  19. Assessment of acreage and vegetation change in Florida's Big Bend tidal wetlands using satellite imagery

    USGS Publications Warehouse

    Raabe, Ellen A.; Stumpf, Richard P.

    1997-01-01

    Fluctuations in sea level and impending development on the west coast of Florida have aroused concern for the relatively pristine tidal marshes of the Big Bend. Landsat Thematic Mapper (TM) images for 1986 and 1995 are processed and evaluated for signs of change. The images cover 250 km of Florida's Big Bend Gulf Coast, encompassing 160,000 acres of tidal marshes. Change is detected using the normalized difference vegetation index (NDVI) and land cover classification. The imagery shows negligible net loss or gain in the marsh over the 9-year period. However, regional changes in biomass are apparent and are due to natural disturbances such as low winter temperatures, fire, storm surge, and the conversion of forest to march. Within the marsh, the most prominent changes in NDVI and in land cover result from the recovery of mangroves from freezes, a decline of transitional upland vegetation, and susceptibility of the marsh edge and interior to variations in tidal flooding.

  20. Clean tailing reclamation: Tailing reprocessing for sulfide removal and vegetation establishment

    SciTech Connect

    Jennings, S.R.; Kruegar, J.

    1997-12-31

    Mine wastes exhibiting elevated heavy metal concentrations are widespread causes of resource degradation in the western US and elsewhere. This problem is further exacerbated by the presence of pyrite that oxidizes upon exposure to the atmosphere resulting in acid generation. Since pyrite was not recovered as a mineral of economic value during mining, it was disposed of in waste piles and tailing ponds that are now a source of acid generation and release of metals to the environment. Tailing cleaning, or sulfide mineral recovery through reprocessing, was evaluated as an innovative reclamation technology. Tailing materials, from both operational and abandoned mines, were collected to evaluate the feasibility of sulfide mineral recovery. Successful mineral separation was performed resulting in a low volume metal sulfide concentrate and a high volume cleaned silicate media. Total metal concentrations were decreased in the cleaned tailing material and elevated in the sulfide concentrate compared with the original tailing chemistry. In greenhouse trials, vegetation establishment in cleaned tailing material was compared with plant growth in topsoil and lime-amended tailings. While vegetation performance was best in the topsoil control, both lime-amended and cleaned tailings displayed adequate plant growth.

  1. Estimating wetland vegetation abundance from Landsat-8 operational land imager imagery: a comparison between linear spectral mixture analysis and multinomial logit modeling methods

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Gong, Zhaoning; Zhao, Wenji; Pu, Ruiliang; Liu, Ke

    2016-01-01

    Mapping vegetation abundance by using remote sensing data is an efficient means for detecting changes of an eco-environment. With Landsat-8 operational land imager (OLI) imagery acquired on July 31, 2013, both linear spectral mixture analysis (LSMA) and multinomial logit model (MNLM) methods were applied to estimate and assess the vegetation abundance in the Wild Duck Lake Wetland in Beijing, China. To improve mapping vegetation abundance and increase the number of endmembers in spectral mixture analysis, normalized difference vegetation index was extracted from OLI imagery along with the seven reflective bands of OLI data for estimating the vegetation abundance. Five endmembers were selected, which include terrestrial plants, aquatic plants, bare soil, high albedo, and low albedo. The vegetation abundance mapping results from Landsat OLI data were finally evaluated by utilizing a WorldView-2 multispectral imagery. Similar spatial patterns of vegetation abundance produced by both fully constrained LSMA algorithm and MNLM methods were observed: higher vegetation abundance levels were distributed in agricultural and riparian areas while lower levels in urban/built-up areas. The experimental results also indicate that the MNLM model outperformed the LSMA algorithm with smaller root mean square error (0.0152 versus 0.0252) and higher coefficient of determination (0.7856 versus 0.7214) as the MNLM model could handle the nonlinear reflection phenomenon better than the LSMA with mixed pixels.

  2. Community Structure and Quality After 10 Years in Two Central Ohio Mitigation Bank Wetlands

    NASA Astrophysics Data System (ADS)

    Spieles, Douglas J.; Coneybeer, Meagan; Horn, Jonathan

    2006-11-01

    We evaluate two 10-year-old mitigation bank wetlands in central Ohio, one created and one with restored and enhanced components, by analysis of vegetation characteristics and by comparison of the year-10 vegetation and macroinvertebrate communities with reference wetlands. To assess different measures of wetland development, we compare the prevalence of native hydrophytes with an index of floristic quality and we evaluate the predictability of these parameters in year 10, given 5 years of data. Results show that the mitigation wetlands in this study meet vegetation performance criteria of native hydrophyte establishment by year 5 and maintain these characteristics through year 10. Species richness and floristic quality, as well as vegetative similarity with reference wetlands, differ among mitigation wetlands in year 1 and also in their rate of change during the first 10 years. The prevalence of native hydrophytes is reasonably predictable by year 10, but 5 years of monitoring is not sufficient to predict future trends of floristic quality in either the created or restored wetland. By year 10, macroinvertebrate taxa richness does not statistically differ among these wetlands, but mitigation wetlands differ from reference sites by tolerance index and by trophic guild dominance. The created wetland herbivore biomass is significantly smaller than its reference, whereas detritivore biomass is significantly greater in the created wetland and smaller in the restored wetland as compared with respective reference wetlands. These analyses illustrate differences in measures of wetland performance and contrast the monitoring duration necessary for legal compliance with the duration required for development of more complex indicators of ecosystem integrity.

  3. Effects of vegetative propagule pressure on the establishment of an introduced clonal plant, Hydrocotyle vulgaris.

    PubMed

    Liu, Ruihua; Chen, Qiuwen; Dong, Bicheng; Yu, Feihai

    2014-01-01

    Some introduced clonal plants spread mainly by vegetative (clonal) propagules due to the absence of sexual reproduction in the introduced range. Propagule pressure (i.e. total number of propagules) may affect the establishment and thus invasion success of introduced clonal plants, and such effects may also depend on habitat conditions. A greenhouse experiment with an introduced plant, Hydrocotyle vulgaris was conducted to investigate the role of propagule pressure on its invasion process. High (five ramets) or low (one ramet) propagule pressure was established either in bare soil or in an experimental plant community consisting of four grassland species. H. vulgaris produced more total biomass under high than under low propagule pressure in both habitat conditions. Interestingly, the size of the H. vulgaris individuals was smaller under high than under low propagule pressure in bare soil, whereas it did not differ between the two propagule pressure treatments in the grassland community. The results indicated that high propagule pressure can ensure the successful invasion in either the grass community or bare soil, and the shift in the intraspecific interaction of H. vulgaris from competition in the bare soil to facilitation in the grassland community may be a potential mechanism. PMID:24981102

  4. Transpiration of gaseous elemental mercury through vegetation in a subtropical wetland in florida

    SciTech Connect

    Lindberg, Steven Eric; Dong, Weijin; Meyers, Tilden

    2002-07-01

    Four seasonal sampling campaigns were carried out in the Florida Everglades to measure elemental Hg vapor (Hg{sup o}) fluxes over emergent macrophytes using a modified Bowen ratio gradient approach. The predominant flux of Hg{sup o} over both invasive cattail and native sawgrass stands was emission; mean day time fluxes over cattail ranged from {approx}20 (winter) to {approx}40 (summer) ng m{sup -2} h{sup -1}. Sawgrass fluxes were about half those over cattail during comparable periods. Emission from vegetation significantly exceeded evasion of Hg{sup o} from the underlying water surface ({approx}1-2 ng m{sup -2} h{sup -1}) measured simultaneously using floating chambers. Among several environmental factors (e.g. CO{sub 2} flux, water vapor flux, wind speed, water, air and leaf temperature, and solar radiation), water vapor exhibited the strongest correlation with Hg{sup o} flux, and transpiration is suggested as an appropriate term to describe this phenomenon. The lack of significant Hg{sup o} emissions from a live, but uprooted (floating) cattail stand suggests that a likely source of the transpired Hg{sup o} is the underlying sediments. The pattern of Hg{sup o} fluxes typically measured indicated a diel cycle with two peaks, possibly related to different gas exchange dynamics: one in early morning related to lacunal gas release, and a second at midday related to transpiration; nighttime fluxes approached zero.

  5. VEGETATION AND ALGAL COMMUNITY COMPOSITION AND DEVELOPMENT OF THREE CONSTRUCTED WETLANDS RECEIVING AGRICULTURAL RUNOFF AND SUBSURFACE DRAINAGE, 1998 TO 2001

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wetland Reservoir Subirrigation Systems (WRSIS) aim to reduce non-point source pollution from agricultural fields while maintaining crop yield and creating wetland wildlife habitat. The WRSIS system directs drainage water from agricultural fields to flow into a passively revegetated constructed wetl...

  6. Application of remote sensing techniques at different scales of observation on wetland evapotranspiration

    NASA Astrophysics Data System (ADS)

    Juan, Chung-Hsin

    The establishment and maintenance of the structure and functions in wetland ecosystems is greatly influenced by hydrologic conditions. Evapotranspiration (ET) is the major output component in the hydrologic water budget. Therefore, in order to provide efficient information for water resources management and the conservation of wetland ecosystems, research on ET is urgently needed. Moreover, to overcome the variable spatial vegetation distribution and the temporal change of wetlands, appropriate remote sensing techniques are also greatly needed. The goal of this research was to study fundamental wetland ET and then with the aid of remote sensing techniques from the micro scale to the macro scale to develop useful wetland ET estimation methods. The study site was located in the Ft. Drum Marsh, Upper St. John's River Basin in Indian River County, Florida. The site is a freshwater marsh with southern cattail ( Typha domingensis Pers.) and sawgrass (Cladium jamaicense Crantz) as the dominant vegetation species. There were four stages of the study: (1) a fundamental ET study with a lysimeter system, (2) ground measurements and analyses of spectral responses of wetland vegetation using a field spectroradiometer, (3) wetland vegetation mapping using aerial hyperspectral images, and (4) application of satellite images to delineate wetland vegetation and estimate marsh-wide ET. The results of the fundamental ET study showed the various important vegetation parameters of sawgrass and cattail. A more appropriate estimation method of canopy resistance for sawgrass and cattail was proposed. Among the various ET estimation methods, the Priestley-Taylor method was found to be most applicable. The ground spectral response measurements of sawgrass and cattail demonstrated a distinguishable difference in red wavebands and normalized difference vegetation index (NDVI), which indicated the spectral separability of the two wetland species. Leaf area index and stomatal resistance

  7. Transplanting native dominant plants to facilitate community development in restored coastal plain wetlands.

    SciTech Connect

    De Steven, Diane; Sharitz, Rebecca R.

    2007-12-01

    Abstract: Drained depressional wetlands are typically restored by plugging ditches or breaking drainage tiles to allow recovery of natural ponding regimes, while relying on passive recolonization from seed banks and dispersal to establish emergent vegetation. However, in restored depressions of the southeastern United States Coastal Plain, certain characteristic rhizomatous graminoid species may not recolonize because they are dispersal-limited and uncommon or absent in the seed banks of disturbed sites. We tested whether selectively planting such wetland dominants could facilitate restoration by accelerating vegetative cover development and suppressing non-wetland species. In an operational-scale project in a South Carolina forested landscape, drained depressional wetlands were restored in early 2001 by completely removing woody vegetation and plugging surface ditches. After forest removal, tillers of two rhizomatous wetland grasses (Panicum hemitomon, Leersia hexandra) were transplanted into singlespecies blocks in 12 restored depressions that otherwise were revegetating passively. Presence and cover of all plant species appearing in planted plots and unplanted control plots were recorded annually. We analyzed vegetation composition after two and four years, during a severe drought (2002) and after hydrologic recovery (2004). Most grass plantings established successfully, attaining 15%–85% cover in two years. Planted plots had fewer total species and fewer wetland species compared to control plots, but differences were small. Planted plots achieved greater total vegetative cover during the drought and greater combined cover of wetland species in both years. By 2004, planted grasses appeared to reduce cover of non-wetland species in some cases, but wetter hydrologic conditions contributed more strongly to suppression of non-wetland species. Because these two grasses typically form a dominant cover matrix in herbaceous depressions, our results indicated that

  8. Impact of corn gluten meal on direct-seeded vegetable seedling establishment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn gluten meal (CGM) may be used as a preemergent or preplant-incorporated herbicide for organic weed control of young developing or emerging weed seedlings; unfortunately, CGM can also adversely impact seedling survival of certain direct-seeded vegetable crops. Various vegetable crop seedlings re...

  9. AmeriFlux US-Tw4 Twitchell East End Wetland

    DOE Data Explorer

    Baldocchi, Dennis [University of California, Berkeley

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Tw4 Twitchell East End Wetland. Site Description - The Twitchell East End Wetland is a newly constructed restored wetland on Twitchell Island, CA. This site and the surrounding region are part of the San Joaquin - Sacramento River Delta drained beginning in the 1850's and subsequently used for agriculture. The site was previously a corn field. The wetland was designed to have a mix of vegetated and open water channels and ponds (due to surface elevation differences). Flooding of the wetland was done gradually beginning in January, 2014. Berms wind throughout the wetland to allow vehicle access. Tule and Cattail plant material from a nearby wetland were spread along the berms immediately prior to flooding to facilitate plant establishment and stabilization of the berms from wind/water erosion. The tower was installed on November 25, 2013.

  10. Pipeline Corridors through wetlands -- Impacts on plant communities: Mill Creek Tributary Crossing, Jefferson County, New York, 1992 Survey

    SciTech Connect

    Van Dyke, G.D.; Shem, L.M.; Zimmerman, R.E.

    1994-12-01

    The goal of the Gas Research Institute Wetland Corridors Program is to identify representative 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 the results of the survey July 1992, at the Mills Creek tributary crossing, Jefferson County, New York. Data were collected from three wetland communities along the 1991 pipeline and compared with predisturbance data obtained in a June 1991 survey. Within one year after pipeline installation, 50% of the soil surface of the ROW in the scrub-shrub community was covered by emergent vegetation. Average wetland values for the ROW in 1992 were lower than in 1991, indicating that the removal of woody plants resulted in a community composed of species with greater fidelity to wetlands. In the emergent marsh community after one year, the average percentage of surface covered by standing water was greater in the ROW than in the adjacent natural areas. The ROW in the forested wetland community also contained standing water, although none was found in the natural forest areas. The entire study site remains a wetland, with the majority of plant species in all sites being either obligate or facultative wetland species. Weighted and unweighted average wetland indices for each community, using all species, indicated wetland vegetation within the newly established ROW.

  11. Assessment of compost application to coal ash disposal sites to promote the rapid vegetation establishment

    NASA Astrophysics Data System (ADS)

    Repmann, F.; Slazak, A.; Babic, M.; Schneider, B. U.; Schaaf, W.; Hüttl, R. F.

    2009-04-01

    In the city of Tuzla, located in Bosnia and Herzegovina, a coal fired thermo electric power plant is operated by the company JP ELEKTROPRIVERDA BIH TERMOELEKTRANA "TUZLA". High amounts of ash are produced by the power plant, which are currently disposed into settlement ponds bordered by dams in natural valleys. A total of four ash disposal sites covering an area of approx. 170 ha have been established during the last decades. Due to the fact that residual ash from coal combustion was found to contain a variety of trace elements (Ni, Cr, As, B), it must be assumed that ash disposal of that magnitude constitutes an environmental problem which is investigated within the EU-FP6 / STREP project "Reintegration of Coal Ash Disposal Sites and Mitigation of Pollution in the West Balkan Area" RECOAL. The main hazards relate to soil and groundwater contamination due to leaching toxins, dust dispersion, and toxins entering the food chain as these disposal sites are used for agricultural purposes. In order to rapidly establish a vegetation cover on barren ash dumps that particularly would prevent dust erosion we assessed the applicability of compost, produced from locally available municipal and industrial organic residues as an amendment to ash to improve substrate fertility. The envisaged remediation technology was considered to be a low cost, easy applicable and rapid method capable of substantially enhancing living conditions of residents in the vicinity of the abandoned disposal sites. Various compost application rates were evaluated in the field on experimental site Divkovici I in Tuzla and additionally in the greenhouse environment at Brandenburg Technical University Cottbus. Field and laboratory tests revealed that plant growth and cover rate can substantially be improved by mixing compost into the upper ash layer to a maximum depth of approx. 20 cm. Besides direct growth observations in the field analysis of soil parameters gave evidence that the fertility of ashy

  12. Numerical modeling of the effects of water flow, sediment transport and vegetation growth on the spatiotemporal patterning of the ridge and slough landscape of the Everglades wetland

    NASA Astrophysics Data System (ADS)

    Lago, Marcelo E.; Miralles-Wilhelm, Fernando; Mahmoudi, Mehrnoosh; Engel, Vic

    2010-10-01

    A numerical model has been developed to simulate the spatiotemporal patterning of the ridge and slough landscape in wetlands, characterized by crests (ridges) and valleys (sloughs) that are elongated parallel to the direction of water flow. The model formulation consists of governing equations for integrated surface water and groundwater flow, sediment transport, and soil accretion, as well as litter production by vegetation growth. The model simulations show how the spatial pattern self-organizes over time with the generation of ridges and sloughs through sediment deposition and erosion driven by the water flow field. The spatial and temporal distributions of the water depth, flow rates and sediment transport processes are caused by differential flow due to vegetation and topography heterogeneities. The model was parameterized with values that are representative of the Everglades wetland in the southern portion of the Florida peninsula in the USA. Model simulation sensitivity was tested with respect to numerical grid size, lateral vegetation growth and the rate of litter production. The characteristic wavelengths of the pattern in the directions along and perpendicular to flow that are simulated with this model develop over time into ridge and slough shapes that resemble field observations. Also, the simulated elevation differences between the ridges and sloughs are of the same order of those typically found in the field. The width of ridges and sloughs was found to be controlled by a lateral vegetation growth distance parameter in a simplified formulation of vegetation growth, which complements earlier modeling results in which a differential peat accretion mechanism alone did not reproduce observations of ridge and slough lateral wavelengths. The results of this work suggest that ridge and slough patterning occurs as a result of vegetation's ability to grow laterally, enhancing sediment deposition in ridge areas, balanced by increased sediment erosion in slough

  13. Reducing sedimentation of depressional wetlands in agricultural landscapes

    USGS Publications Warehouse

    Skagen, S.K.; Melcher, C.P.; Haukos, D.A.

    2008-01-01

    Depressional wetlands in agricultural landscapes are easily degraded by sediments and contaminants accumulated from their watersheds. Several best management practices can reduce transport of sediments into wetlands, including the establishment of vegetative buffers. We summarize the sources, transport dynamics, and effect of sediments, nutrients, and contaminants that threaten wetlands and the current knowledge of design and usefulness of grass buffers for protecting isolated wetlands. Buffer effectiveness is dependent on several factors, including vegetation structure, buffer width, attributes of the surrounding watershed (i.e., area, vegetative cover, slope and topography, soil type and structure, soil moisture, amount of herbicides and pesticides applied), and intensity and duration of rain events. To reduce dissolved contaminants from runoff, the water must infiltrate the soil where microbes or other processes can break down or sequester contaminants. But increasing infiltration also diminishes total water volume entering a wetland, which presents threats to wetland hydrology in semi-arid regions. Buffer effectiveness may be enhanced significantly by implementing other best management practices (e.g., conservation tillage, balancing input with nutrient requirements for livestock and crops, precision application of chemicals) in the surrounding watershed to diminish soil erosion and associated contaminant runoff. Buffers require regular maintenance to remove sediment build-up and replace damaged or over-mature vegetation. Further research is needed to establish guidelines for effective buffer width and structure, and such efforts should entail a coordinated, regional, multi-scale, multidisciplinary approach to evaluate buffer effectiveness and impacts. Direct measures in "real-world" systems and field validations of buffer-effectiveness models are crucial next steps in evaluating how grass buffers will impact the abiotic and biotic variables attributes that

  14. Seasonal Dynamics of Soil Labile Organic Carbon and Enzyme Activities in Relation to Vegetation Types in Hangzhou Bay Tidal Flat Wetland

    PubMed Central

    Shao, Xuexin; Yang, Wenying; Wu, Ming

    2015-01-01

    Soil labile organic carbon and soil enzymes play important roles in the carbon cycle of coastal wetlands that have high organic carbon accumulation rates. Soils under three vegetations (Phragmites australis, Spartina alterniflora, and Scirpusm mariqueter) as well as bare mudflat in Hangzhou Bay wetland of China were collected seasonally. Seasonal dynamics and correlations of soil labile organic carbon fractions and soil enzyme activities were analyzed. The results showed that there were significant differences among vegetation types in the contents of soil organic carbon (SOC) and dissolved organic carbon (DOC), excepting for that of microbial biomass carbon (MBC). The P. australis soil was with the highest content of both SOC (7.86 g kg-1) and DOC (306 mg kg-1), while the S. mariqueter soil was with the lowest content of SOC (6.83 g kg-1), and the bare mudflat was with the lowest content of DOC (270 mg kg-1). Soil enzyme activities were significantly different among vegetation types except for urease. The P. australis had the highest annual average activity of alkaline phosphomonoesterase (21.4 mg kg-1 h-1), and the S. alterniflora had the highest annual average activities of β-glycosidase (4.10 mg kg-1 h-1) and invertase (9.81mg g-1 24h-1); however, the bare mudflat had the lowest activities of alkaline phosphomonoesterase (16.2 mg kg-1 h-1), β-glycosidase (2.87 mg kg-1 h-1), and invertase (8.02 mg g-1 24h-1). Analysis also showed that the soil labile organic carbon fractions and soil enzyme activities had distinct seasonal dynamics. In addition, the soil MBC content was significantly correlated with the activities of urease and β-glucosidase. The DOC content was significantly correlated with the activities of urease, alkaline phosphomonoesterase, and invertase. The results indicated that vegetation type is an important factor influencing the spatial-temporal variation of soil enzyme activities and labile organic carbon in coastal wetlands. PMID:26560310

  15. Effects of irrigation on seed production and vegetative characteristics of four moist-soil plants on impounded wetlands in California

    USGS Publications Warehouse

    Mushet, D.M.; Euliss, N.H., Jr.; Harris, S.W.

    1992-01-01

    We examined the effects of irrigation on 4 moist-soil plants commonly managed for waterfowl in the Sacramento Valley, California. Irrigation resulted in taller and heavier swamp timothy (Heleochloa schoenoides), pricklegrass (Crypsis niliaca), and sprangletop (Leptochloa fasicularis). Barnyardgrass (Echinochloa crusgalli) grew taller in irrigated wetlands, but no significant difference in weight was detected. Only sprangletop yielded larger seed masses in response to irrigation. Without irrigation, swamp timothy and pricklegrass assumed a typical prostrate growth form, but with irrigation, they assumed a vertical growth form. Irrigation did not significantly affect plant density. Because of rising water costs, wetland managers should consider wildlife management objectives and plant responses before implementing irrigation practices.

  16. Establishing Minimum Flow Requirements Based on Benthic Vegetation: What are Some Issues Related to Identifying Quantity of Inflow and Tools Used to Quantify Ecosystem Response?

    NASA Astrophysics Data System (ADS)

    Hunt, M. J.; Nuttle, W. K.; Cosby, B. J.; Marshall, F. E.

    2005-05-01

    Establishing minimum flow requirements in aquatic ecosystems is one way to stipulate controls on water withdrawals in a watershed. The basis of the determination is to identify the amount of flow needed to sustain a threshold ecological function. To develop minimum flow criteria an understanding of ecological response in relation to flow is essential. Several steps are needed including: (1) identification of important resources and ecological functions, (2) compilation of available information, (3) determination of historical conditions, (4) establishment of technical relationships between inflow and resources, and (5) identification of numeric criteria that reflect the threshold at which resources are harmed. The process is interdisciplinary requiring the integration of hydrologic and ecologic principles with quantitative assessments. The tools used quantify the ecological response and key questions related to how the quantity of flow influences the ecosystem are examined by comparing minimum flow determination in two different aquatic systems in South Florida. Each system is characterized by substantial hydrologic alteration. The first, the Caloosahatchee River is a riverine system, located on the southwest coast of Florida. The second, the Everglades- Florida Bay ecotone, is a wetland mangrove ecosystem, located on the southern tip of the Florida peninsula. In both cases freshwater submerged aquatic vegetation (Vallisneria americana or Ruppia maritima), located in areas of the saltwater- freshwater interface has been identified as a basis for minimum flow criteria. The integration of field studies, laboratory studies, and literature review was required. From this information we developed ecological modeling tools to quantify and predict plant growth in response to varying environmental variables. Coupled with hydrologic modeling tools questions relating to the quantity and timing of flow and ecological consequences in relation to normal variability are addressed.

  17. Effects of a long-term disturbance on arthropods and vegetation in subalpine wetlands: manifestations of pack stock grazing in early versus mid-season.

    PubMed

    Holmquist, Jeffrey G; Schmidt-Gengenbach, Jutta; Haultain, Sylvia A

    2013-01-01

    Conclusions regarding disturbance effects in high elevation or high latitude ecosystems based solely on infrequent, long-term sampling may be misleading, because the long winters may erase severe, short-term impacts at the height of the abbreviated growing season. We separated a) long-term effects of pack stock grazing, manifested in early season prior to stock arrival, from b) additional pack stock grazing effects that might become apparent during annual stock grazing, by use of paired grazed and control wet meadows that we sampled at the beginning and end of subalpine growing seasons. Control meadows had been closed to grazing for at least two decades, and meadow pairs were distributed across Sequoia National Park, California, USA. The study was thus effectively a landscape-scale, long-term manipulation of wetland grazing. We sampled arthropods at these remote sites and collected data on associated vegetation structure. Litter cover and depth, percent bare ground, and soil strength had negative responses to grazing. In contrast, fauna showed little response to grazing, and there were overall negative effects for only three arthropod families. Mid-season and long-term results were generally congruent, and the only indications of lower faunal diversity on mid-season grazed wetlands were trends of lower abundance across morphospecies and lower diversity for canopy fauna across assemblage metrics. Treatment x Season interactions almost absent. Thus impacts on vegetation structure only minimally cascaded into the arthropod assemblage and were not greatly intensified during the annual growing season. Differences between years, which were likely a response to divergent snowfall patterns, were more important than differences between early and mid-season. Reliance on either vegetation or faunal metrics exclusively would have yielded different conclusions; using both flora and fauna served to provide a more integrative view of ecosystem response. PMID:23308297

  18. Effects of a Long-Term Disturbance on Arthropods and Vegetation in Subalpine Wetlands: Manifestations of Pack Stock Grazing in Early versus Mid-Season

    PubMed Central

    Holmquist, Jeffrey G.; Schmidt-Gengenbach, Jutta; Haultain, Sylvia A.

    2013-01-01

    Conclusions regarding disturbance effects in high elevation or high latitude ecosystems based solely on infrequent, long-term sampling may be misleading, because the long winters may erase severe, short-term impacts at the height of the abbreviated growing season. We separated a) long-term effects of pack stock grazing, manifested in early season prior to stock arrival, from b) additional pack stock grazing effects that might become apparent during annual stock grazing, by use of paired grazed and control wet meadows that we sampled at the beginning and end of subalpine growing seasons. Control meadows had been closed to grazing for at least two decades, and meadow pairs were distributed across Sequoia National Park, California, USA. The study was thus effectively a landscape-scale, long-term manipulation of wetland grazing. We sampled arthropods at these remote sites and collected data on associated vegetation structure. Litter cover and depth, percent bare ground, and soil strength had negative responses to grazing. In contrast, fauna showed little response to grazing, and there were overall negative effects for only three arthropod families. Mid-season and long-term results were generally congruent, and the only indications of lower faunal diversity on mid-season grazed wetlands were trends of lower abundance across morphospecies and lower diversity for canopy fauna across assemblage metrics. Treatment x Season interactions almost absent. Thus impacts on vegetation structure only minimally cascaded into the arthropod assemblage and were not greatly intensified during the annual growing season. Differences between years, which were likely a response to divergent snowfall patterns, were more important than differences between early and mid-season. Reliance on either vegetation or faunal metrics exclusively would have yielded different conclusions; using both flora and fauna served to provide a more integrative view of ecosystem response. PMID:23308297

  19. Seasonal variability of turbulent fluxes over a vegetated subtropical coastal wetland measured by large aperture scintillometry and eddy covariance

    NASA Astrophysics Data System (ADS)

    Guyot, Adrien; Gray, Michael; Riesenkamp, Michiel; Lockington, David; McGowan, Hamish

    2016-04-01

    Subtropical coastal wetlands are particularly susceptible to the impacts of climate variability: their recharge rates strongly depend on rainfall, and the occurrence of prolonged droughts or wet periods have direct consequences for wetland health and bio-diversity. There is therefore a need to close the water budget of these ecosystems and this requires the quantification of rates of evaporation/evapotranspiration. However, few studies have documented land-atmosphere exchanges over wetlands for which water level varies considerably during a typical annual cycle. Here, we present a year of turbulent flux observations over a wetland on the subtropical coast of eastern Australia. Large Aperture Scintillometry and Eddy Covariance are used to derive sensible heat fluxes. Latent heat fluxes are also derived through an energy balance for both instruments' observations and also directly through Eddy Covariance. Careful sensitivity analysis of the instrumental footprints, seasonal variations of land surface parameters such as roughness length and displacement height are examined and subsequent uncertainties in the derived turbulent fluxes are discussed. Finally we show how these observations can also help better understand hydrological processes at the catchment scale.

  20. Vegetation patches improve the establishment of Salvia mexicana seedlings by modifying microclimatic conditions

    NASA Astrophysics Data System (ADS)

    Mendoza-Hernández, Pedro E.; Rosete-Rodríguez, Alejandra; Sánchez-Coronado, María E.; Orozco, Susana; Pedrero-López, Luis; Méndez, Ignacio; Orozco-Segovia, Alma

    2014-07-01

    Human disturbance has disrupted the dynamics of plant communities. To restore these dynamics, we could take advantage of the microclimatic conditions generated by remaining patches of vegetation and plastic mulch. These microclimatic conditions might have great importance in restoring disturbed lava fields located south of Mexico City, where the rock is exposed and the soil is shallow. We evaluated the effects of both the shade projected by vegetation patches and plastic mulch on the mean monthly soil surface temperature ( T ss) and photosynthetic photon flux density (PPFD) and on the survival and growth of Salvia mexicana throughout the year. This species was used as a phytometer of microsite quality. Shade reduced the T ss to a greater extent than mulch did. Both survival and growth were enhanced by shade and mulch, and the PPFD was related with seedling growth. During the dry season, plant biomass was lost, and there was a negative effect of PPFD on plant growth. At micro-meteorological scales, the use of shade projected by patches of vegetation and mulch significantly reduced the mortality of S. mexicana and enhanced its growth. Survival and growth of this plant depended on the environmental quality of microsites on a small scale, which was determined by the environmental heterogeneity of the patches and the landscape. For plant restoration, microsite quality must be evaluated on small scales, but on a large scale it may be enough to take advantage of landscape shade dynamics and the use of mulch to increase plant survival and growth.

  1. Vegetation patches improve the establishment of Salvia mexicana seedlings by modifying microclimatic conditions

    NASA Astrophysics Data System (ADS)

    Mendoza-Hernández, Pedro E.; Rosete-Rodríguez, Alejandra; Sánchez-Coronado, María E.; Orozco, Susana; Pedrero-López, Luis; Méndez, Ignacio; Orozco-Segovia, Alma

    2013-04-01

    Human disturbance has disrupted the dynamics of plant communities. To restore these dynamics, we could take advantage of the microclimatic conditions generated by remaining patches of vegetation and plastic mulch. These microclimatic conditions might have great importance in restoring disturbed lava fields located south of Mexico City, where the rock is exposed and the soil is shallow. We evaluated the effects of both the shade projected by vegetation patches and plastic mulch on the mean monthly soil surface temperature (T ss) and photosynthetic photon flux density (PPFD) and on the survival and growth of Salvia mexicana throughout the year. This species was used as a phytometer of microsite quality. Shade reduced the T ss to a greater extent than mulch did. Both survival and growth were enhanced by shade and mulch, and the PPFD was related with seedling growth. During the dry season, plant biomass was lost, and there was a negative effect of PPFD on plant growth. At micro-meteorological scales, the use of shade projected by patches of vegetation and mulch significantly reduced the mortality of S. mexicana and enhanced its growth. Survival and growth of this plant depended on the environmental quality of microsites on a small scale, which was determined by the environmental heterogeneity of the patches and the landscape. For plant restoration, microsite quality must be evaluated on small scales, but on a large scale it may be enough to take advantage of landscape shade dynamics and the use of mulch to increase plant survival and growth.

  2. Operational actual wetland evapotranspiration estimation for the Everglades using MODIS imagery

    NASA Astrophysics Data System (ADS)

    Melesse, Assefa; Cereon, Cristobal

    2014-05-01

    Wetlands are one of the most important ecosystems with varied functions and structures. Humans have drained wetlands and altered the structure and functions of wetlands for various uses. Wetland restoration efforts require assessment of the level of ecohydrological restoration for the intended functions. Among the various indicators of success in wetland restoration, achieving the desired water level (hydrology) is the most important, faster to achieve and easier to monitor than the establishment of the hydric soils and wetland vegetation. Monitoring wetland hydrology using remote sensing based evapotranspiration (ET) is a useful tool and approach since point measurements for understanding the temporal (before and after restoration) and spatial (impacted and restored) parts of the wetland are not effective for large areas. Evapotranspiration accounts over 80% of the water budget of the wetlands necessitating the need for spatiotemporal monitoring of ET flux. A study employing remotely sensed data from Moderate Resolution Imaging Spectroradiometer (MODIS) and modeling tools was conducted for a weekly spatial estimation of Everglades ET. Weekly surface temperature data were generated from the MODIS thermal band and evaporative fraction was estimated using the simplified surface energy balance (SSEB) approach. Based on the Simple Method, potential ET (PET) was estimated. Actual weekly wetland ET was computed as the (product of the PET and evaporative fraction). The ET product will be useful information for environmental restoration and wetland hydrology managers. The on-going restoration and monitoring work in the Everglades will benefit from this product and assist in evaluating progress and success in the restoration.

  3. Future vegetation patterns and primary production in the coastal wetlands of East China under sea level rise, sediment reduction, and saltwater intrusion

    NASA Astrophysics Data System (ADS)

    Ge, Zhen-Ming; Cao, Hao-Bin; Cui, Li-Fang; Zhao, Bin; Zhang, Li-Quan

    2015-10-01

    To explore the effects of sea level rise (SLR), sediment reduction (SR), and saltwater intrusion (SWI) on the vegetation patterns and primary production of one exotic (Spartina alterniflora) and two native dominant (Scirpus mariqueter and Phragmites australis) species in the coastal wetlands of East China, range expansion monitoring and stress experiments were conducted, followed by model prediction. After a rapid invasion period, the expansion rate of S. alterniflora slowed down due to the decreasing availability of suitable habitat under prolonged inundation. SLR was shown to decrease the colonization of S. alterniflora and the native P. australis up to 2100. In contrast, the native S. mariqueter that has a high tolerance of inundation increased in area following SLR, due to a reduction in competition from S. alterniflora in low-lying habitats and even recolonized areas previously invaded by the exotic species. The combination of SLR and SR resulted in further degradation of S. alterniflora and P. australis, while the area of S. mariqueter was not reduced significantly. The decrease in the area of vegetation would reduce the gross primary production under SLR and SR. SWI exacerbates the impacts, especially for P. australis, because S. alterniflora and S. mariqueter have a higher tolerance of salinity. Thus, the coastal vegetation pattern was predicted to be modified due to species-specific adaption to changed geophysical features. This study indicated that the native species better adapted to prolonged inundation and increased salinity might once again become key contributors to primary production on the muddy coasts of East China.

  4. Pipeline corridors through wetlands

    SciTech Connect

    Zimmerman, R.E.; Wilkey, P.L.; Isaacson, H.R.

    1992-12-01

    This paper presents preliminary findings from six vegetational surveys of gas pipeline rights-of-way (ROW) through wetlands and quantifies the impacts of a 20-year-old pipeline ROW through a boreal forest wetland. Six sites of various ages were surveyed in ecosystems ranging from coastal marsh to forested wetland. At all sites except one, both the number and the percentage of wetland species on the Row approximated or exceeded those in the adjacent natural area. The boreal forest study showed that (1) adjacent natural wetland areas were not altered in type; (2) water sheet flow restriction had been reversed by nature; (3) no nonnative plant species invaded the natural area; (4) three-quarters of the ROW area was a wetland, and (5) the ROW increased diversity.

  5. Pipeline corridors through wetlands

    SciTech Connect

    Zimmerman, R.E.; Wilkey, P.L. ); Isaacson, H.R. )

    1992-01-01

    This paper presents preliminary findings from six vegetational surveys of gas pipeline rights-of-way (ROW) through wetlands and quantifies the impacts of a 20-year-old pipeline ROW through a boreal forest wetland. Six sites of various ages were surveyed in ecosystems ranging from coastal marsh to forested wetland. At all sites except one, both the number and the percentage of wetland species on the Row approximated or exceeded those in the adjacent natural area. The boreal forest study showed that (1) adjacent natural wetland areas were not altered in type; (2) water sheet flow restriction had been reversed by nature; (3) no nonnative plant species invaded the natural area; (4) three-quarters of the ROW area was a wetland, and (5) the ROW increased diversity.

  6. Flue gas desulfurization sludge: establishment of vegetation on ponded and soil-applied waste. Final report January 1977-September 1981

    SciTech Connect

    Giordano, P.M.; Mays, D.A.; Soileau, J.M.

    1984-01-01

    The report gives results of research to identify and evaluate forms of vegetation and methods of their establishment for reclaiming retired flue gas desulfurization sludge ponds. Also studied were the soil liming value of limestone scrubber sludge (LSS) and plant uptake and percolation losses of some chemical nutrients in the sludge. Several vegetation schemes were evaluated between 1977 and 1982 for covering and stabilizing LSS at Colbert Steam Plant, Cherokee, AL, and Shawnee Steam Plant, Paducah, KY. Eleven tree and 10 grass or legume species were tested for adaptability and survival when planted directly in LSS or in LSS amended with soil, municipal sewage sludge, or standard potting mix. Other studies indicated that LSS apparently has sufficient unreacted limestone to be a satisfactory soil liming agent.

  7. The Carolina Bay Restoration Project: Implementation and Management of a Wetland Mitigation Bank.

    SciTech Connect

    Barton, Christopher; DeSteven, Diane; Sharitz, Rebecca; Kilgo, John; Imm, Donald; Kolka, Randy; Blake, John, I.

    2003-01-01

    A wetlands Mitigation Bank was established at the Savannah River Site (SRS) in 1997 as a compensatory alternative for unavoidable wetland losses associated with future authorized construction and environmental restoration projects in SRS wetlands. The Bank was intended not only to hasten mitigation efforts with respect to regulatory requirements and implementation, but also to provide onsite and fully functional compensation of impacted wetland acreage prior to any impact. Restoration and enhancement of small isolated wetlands, as well as major bottomland wetland systems scattered throughout the nonindustrialized area of SRS were designated for inclusion in the Bank. Based on information and techniques gained from previous research efforts involving Carolina bay wetlands (DOE 1997), a project to restore degraded Carolina bays on SRS has been undertaken to serve as the initial ''deposit'' in The Bank. There are over 300 Carolina bays or bay-like depression wetlands on the SRS, of which an estimated two-thirds were ditched or disturbed prior to federal occupation of the Site (Kirkman et al., 1996). These isolated wetlands range from small ephemeral depressions to large permanent ponds of 10-50 hectares in size. They provide habitat to support a wide range of rare plant species, and many vertebrates (birds, amphibians, bats). Historical impacts to the Carolina bays at SRS were primarily associated with agricultural activities. Bays were often drained tilled and planted to crops. The consequence was a loss in the wetland hydrologic cycle, the native wetland vegetation, and associated wildlife. The purpose of this mitigation and research project is to restore the functions and vegetation typical of intact depression wetlands and, in doing so, to enhance habitat for wetland dependent wildlife on SRS.

  8. An integrated approach to assess broad-scale condition of coastal wetlands - The Gulf of Mexico Coastal Wetlands pilot survey

    USGS Publications Warehouse

    Nestlerode, J.A.; Engle, V.D.; Bourgeois, P.; Heitmuller, P.T.; Macauley, J.M.; Allen, Y.C.

    2009-01-01

    The Environmental Protection Agency (EPA) and U.S. Geological Survey (USGS) initiated a two-year regional pilot survey in 2007 to develop, test, and validate tools and approaches to assess the condition of northern Gulf of Mexico (GOM) coastal wetlands. Sampling sites were selected from estuarine and palustrine wetland areas with herbaceous, forested, and shrub/scrub habitats delineated by the US Fish and Wildlife Service National Wetlands Inventory Status and Trends (NWI S&T) program and contained within northern GOM coastal watersheds. A multi-level, stepwise, iterative survey approach is being applied to multiple wetland classes at 100 probabilistically-selected coastal wetlands sites. Tier 1 provides information at the landscape scale about habitat inventory, land use, and environmental stressors associated with the watershed in which each wetland site is located. Tier 2, a rapid assessment conducted through a combination of office and field work, is based on best professional judgment and on-site evidence. Tier 3, an intensive site assessment, involves on-site collection of vegetation, water, and sediment samples to establish an integrated understanding of current wetland condition and validate methods and findings from Tiers 1 and 2. The results from this survey, along with other similar regional pilots from the Mid-Atlantic, West Coast, and Great Lakes Regions will contribute to a design and implementation approach for the National Wetlands Condition Assessment to be conducted by EPA's Office of Water in 2011. ?? Springer Science+Business Media B.V. 2008.

  9. Wetland restoration and compliance issues on the Savannah River site

    SciTech Connect

    Wein, G.R.; McLeod, K.W.; Sharitz, R.R. )

    1993-01-01

    Operation of the nuclear production reactors on the Savannah River Site has faced potential conflicts with wetland regulations on several occasions. This paper provides two examples in which regulatory compliance and restoration research have been meshed, providing both compliance and better knowledge to aid future regulatory needs. The decision to restart the L reactor required the mitigation of thermal effluents under Sec. 316 of the Clean Water Act. The National Pollutant Discharge Elimination System, permit for the selected mitigation alternative, a 405-ha once-through cooling reservoir, required the establishment of a balanced biological community (BBC) within the lake. To promote the development of a BBC, the reservoir was seeded with water from an existing BBC (Par Pond) and stocked with fish and had artificial reefs constructed. The US Department of Energy (DOE) also requested that the Savannah River Ecology Laboratory establish littoral/wetland vegetation along the shoreline to provide aquatic and wildlife habitat, shoreline stabilization, and a good faith effort toward the establishment of a BBC. The development of wetland vegetation was deemed important to the successful development of a BBC within L Lake. However, in a similar cooling reservoir system constructed in 1957 (Par Pond), wetland vegetation successfully developed without any planting effort. Other than the good faith effort toward a BBC, there is no reason to assume a littoral/wetland community would not develop of its own accord. However, research conducted at L Lake indicates that the planting of wetland vegetation at L Lake accelerated the process of natural selection over that of areas that were not planted.

  10. The potential use of storm water and effluent from a constructed wetland for re-vegetating a degraded pyrite trail in Queen Elizabeth National Park, Uganda

    NASA Astrophysics Data System (ADS)

    Osaliya, R.; Kansiime, F.; Oryem-Origa, H.; Kateyo, E.

    During the operation of the Kilembe Mines (copper mining) a cobaltiferous stockpile was constructed, which began to erode after the closure of the mines in the early 1970s. The erosion of the pyrite stockpile resulted in a large acid trail all the way to Lake George (a Ramsar site). The acid trail contaminated a large area of Queen Elizabeth National Park (QENP) resulting in the death of most of the shallow-rooted vegetation. Processes and conditions created by storm water and effluent from a constructed wetland were assessed for vegetation regeneration in the degraded QENP pyrite trail. Cynodon dactylon, Imperata cylindrica and Hyparrhenia filipendula dominated the regeneration zone (RZ) where storm water and effluent from a constructed wetland was flowing; and the adjacent unpolluted area (UP) with importance value indices of 186.4 and 83.3 respectively. Typha latifolia and C. dactylon formed two distinct vegetation sub-zones within the RZ with the former inhabiting areas with a higher water table. Soil pH was significantly higher in the RZ, followed by UP and bare pyrite trail (BPT) at both 0-15 cm and 16-30 cm depths. Soil electrical conductivity was not significantly different in the RZ and BPT but significantly higher than that in UP for both depths. For 0-15 cm depth, RZ had significantly higher concentrations of copper than BPT and UP which had similar concentrations. Still at this depth (0-15 cm), the unpolluted area had significantly higher concentrations of total phosphorus and total nitrogen than the regeneration zone and the bare pyrite trail which had similar concentrations. The RZ dominated by Typha had significantly higher concentrations of TP and TN compared to the RZ dominated by Cynodon. The concentrations of NH 4-N were significantly lower in Typha regeneration zone than in CRZ at 0-15 cm depth but similar at 16-30 cm depth. At 16-30 cm depth, concentrations of copper were significantly higher in the regeneration zone followed by the bare pyrite

  11. Influence of wetland size on aquatic communities within wetland reservoir subirrigation systems in northwestern Ohio.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Establishment of a water management system known as the wetland-reservoir subirrigation system (WRSIS) results in the creation of wetlands adjacent to agricultural fields. Specifically, each WRSIS consists of one wetland designed to process agricultural chemicals (WRSIS wetlands) and one wetland to ...

  12. Selective coal mine overburden treatment with topsoil and compost to optimise pasture or native vegetation establishment.

    PubMed

    Spargo, A; Doley, D

    2016-11-01

    Overburden at a coal mine in the Hunter Valley, New South Wales, was stored in a flat-topped artificial mound with 14-degree side slopes. Topsoil was scarce, dispersive and readily eroded. A split-plot factorial experiment applied an enhanced municipal solid waste compost at 0, 60 or 100 t ha(-1) to untreated overburden or to overburden covered with 0.1 m of topsoil. Two seeding treatments, of trees and shrubs or of pasture species, were applied to two 0.5-ha replicates of each surface treatment. Substrate physical and chemical properties and vegetation attributes were assessed 2.5 years later. Compost application to both topsoil and overburden significantly increased total N, P, Cu and Zn, soluble K, Ca and Mg, and significantly reduced soluble Na and pH. Mean tree density, size and total canopy cover were significantly greater with compost applied at 60 t ha(-1) to overburden than with all other treatments, especially those on topsoil where tree growth was inhibited by undesired species. Compost application to overburden and topsoil at 100 t ha(-1) significantly increased biomass of desired pasture species and significantly reduced undesired species cover compared with unamended topsoil and the extent of bare ground compared with unamended overburden. Successful development of woody species on overburden and pastures on both overburden and topsoil treated with compost provides opportunities for new combinations of landscape design, surface preparation and plant species introductions to increase the stability of final landforms, the effectiveness of resource use, and the delivery of commercial and biodiversity benefits from mine site rehabilitation. PMID:27497311

  13. FGD liner experiments with wetlands

    SciTech Connect

    Mitsch, W.J.; Ahn, C.; Wolfe, W.E.

    1999-07-01

    The construction of artificial wetlands for wastewater treatment often requires impermeable liners not only to protect groundwater resources but also to ensure that there is adequate water in the wetland to support appropriate aquatic life, particularly wetland vegetation. Liners or relatively impervious site soils are very important to the success of constructed treatment wetlands in areas where ground water levels are typically close to the ground surface. This study, carried out at the Olentangy River Wetland Research Park, investigated the use of FGD material from sulfur scrubbers as a possible liner material for constructed wetlands. While several studies have investigated the use of FGD material to line ponds, no studies have investigated the use of this material as a liner for constructed wetlands. They used experimental mesocosms to see the effect of FGD liner materials in constructed wetlands on water quality and on wetland plant growth. This paper presents the results of nutrient analyses and physicochemical investigation of leachate and surface outflow water samples collected from the mesocosms. Plant growth and biomass of wetland vegetation are also included in this paper. First two year results are reported by Ahn et al. (1998, 1999). The overall goal of this study is the identification of advantages and disadvantages of using FGD by-product as an artificial liner in constructed wetlands.

  14. Assessment of acreage and vegetation change in Florida`s Big Bend tidal wetlands using satellite imagery

    SciTech Connect

    Raabe, E.A.; Stumpf, R.P.

    1997-06-01

    Fluctuations in sea level and impending development on the west coast of Florida have aroused concern for the relatively pristine tidal marshes of the Big Bend. Landsat Thematic Mapper (TM) images for 1986 and 1995 are processed and evaluated for signs of change. The images cover 250 km of Florida`s Big Bend Gulf Coast, encompassing 160,000 acres of tidal marshes. Change is detected using the normalized difference vegetation index (NDVI) and land cover classification. The imagery shows negligible net loss or gain in the marsh over the 9-year period. However, regional changes in biomass are apparent and are due to natural disturbances such as low winter temperatures, fire, storm surge, and the conversion of forest to marsh. Within the marsh, the most prominent changes in NDVI and in land cover result from the recovery of mangroves from freezes, a decline of transitional upland vegetation, and susceptibility of the marsh edge and interior to variations in tidal flooding.

  15. Establishing the Capability of a 1D SVAT Modelling Scheme in Predicting Key Biophysical Vegetation Characterisation Parameters

    NASA Astrophysics Data System (ADS)

    Ireland, Gareth; Petropoulos, George P.; Carlson, Toby N.; Purdy, Sarah

    2015-04-01

    Sensitivity analysis (SA) consists of an integral and important validatory check of a computer simulation model before it is used to perform any kind of analysis. In the present work, we present the results from a SA performed on the SimSphere Soil Vegetation Atmosphere Transfer (SVAT) model utilising a cutting edge and robust Global Sensitivity Analysis (GSA) approach, based on the use of the Gaussian Emulation Machine for Sensitivity Analysis (GEM-SA) tool. The sensitivity of the following model outputs was evaluated: the ambient CO2 concentration and the rate of CO2 uptake by the plant, the ambient O3 concentration, the flux of O3 from the air to the plant/soil boundary, and the flux of O3 taken up by the plant alone. The most sensitive model inputs for the majority of model outputs were related to the structural properties of vegetation, namely, the Leaf Area Index, Fractional Vegetation Cover, Cuticle Resistance and Vegetation Height. External CO2 in the leaf and the O3 concentration in the air input parameters also exhibited significant influence on model outputs. This work presents a very important step towards an all-inclusive evaluation of SimSphere. Indeed, results from this study contribute decisively towards establishing its capability as a useful teaching and research tool in modelling Earth's land surface interactions. This is of considerable importance in the light of the rapidly expanding use of this model worldwide, which also includes research conducted by various Space Agencies examining its synergistic use with Earth Observation data towards the development of operational products at a global scale. This research was supported by the European Commission Marie Curie Re-Integration Grant "TRANSFORM-EO". SimSphere is currently maintained and freely distributed by the Department of Geography and Earth Sciences at Aberystwyth University (http://www.aber.ac.uk/simsphere). Keywords: CO2 flux, ambient CO2, O3 flux, SimSphere, Gaussian process emulators

  16. Assessment of Vegetation Establishment on Tailings Dam at an Iron Ore Mining Site of Suburban Beijing, China, 7 Years After Reclamation with Contrasting Site Treatment Methods

    NASA Astrophysics Data System (ADS)

    Yan, Demin; Zhao, Fangying; Sun, Osbert Jianxin

    2013-09-01

    Strip-mining operations greatly disturb soil, vegetation and landscape elements, causing many ecological and environmental problems. Establishment of vegetation is a critical step in achieving the goal of ecosystem restoration in mining areas. At the Shouyun Iron Ore Mine in suburban Beijing, China, we investigated selective vegetation and soil traits on a tailings dam 7 years after site treatments with three contrasting approaches: (1) soil covering (designated as SC), (2) application of a straw mat, known as "vegetation carpet", which contains prescribed plant seed mix and water retaining agent (designated as VC), on top of sand piles, and (3) combination of soil covering and application of vegetation carpet (designated as SC+VC). We found that after 7 years of reclamation, the SC+VC site had twice the number of plant species and greater biomass than the SC and VC sites, and that the VC site had a comparable plant abundance with the SC+VC site but much less biodiversity and plant coverage. The VC site did not differ with the SC site in the vegetation traits, albeit low soil fertility. It is suggested that application of vegetation carpet can be an alternative to introduction of topsoil for treatment of tailings dam with fine-structured substrate of ore sands. However, combination of topsoil treatment and application of vegetation carpet greatly increases vegetation coverage and plant biodiversity, and is therefore a much better approach for assisting vegetation establishment on the tailings dam of strip-mining operations. While application of vegetation carpet helps to stabilize the loose surface of fine-structured mine wastes and to introduce seed bank, introduction of fertile soil is necessary for supplying nutrients to plant growth in the efforts of ecosystem restoration of mining areas.

  17. Assessment of vegetation establishment on tailings dam at an iron ore mining site of suburban Beijing, China, 7 years after reclamation with contrasting site treatment methods.

    PubMed

    Yan, Demin; Zhao, Fangying; Sun, Osbert Jianxin

    2013-09-01

    Strip-mining operations greatly disturb soil, vegetation and landscape elements, causing many ecological and environmental problems. Establishment of vegetation is a critical step in achieving the goal of ecosystem restoration in mining areas. At the Shouyun Iron Ore Mine in suburban Beijing, China, we investigated selective vegetation and soil traits on a tailings dam 7 years after site treatments with three contrasting approaches: (1) soil covering (designated as SC), (2) application of a straw mat, known as "vegetation carpet", which contains prescribed plant seed mix and water retaining agent (designated as VC), on top of sand piles, and (3) combination of soil covering and application of vegetation carpet (designated as SC+VC). We found that after 7 years of reclamation, the SC+VC site had twice the number of plant species and greater biomass than the SC and VC sites, and that the VC site had a comparable plant abundance with the SC+VC site but much less biodiversity and plant coverage. The VC site did not differ with the SC site in the vegetation traits, albeit low soil fertility. It is suggested that application of vegetation carpet can be an alternative to introduction of topsoil for treatment of tailings dam with fine-structured substrate of ore sands. However, combination of topsoil treatment and application of vegetation carpet greatly increases vegetation coverage and plant biodiversity, and is therefore a much better approach for assisting vegetation establishment on the tailings dam of strip-mining operations. While application of vegetation carpet helps to stabilize the loose surface of fine-structured mine wastes and to introduce seed bank, introduction of fertile soil is necessary for supplying nutrients to plant growth in the efforts of ecosystem restoration of mining areas. PMID:23811774

  18. Avian utilization of subsidence wetlands

    SciTech Connect

    Nawrot, J.R.; Conley, P.S.; Smout, C.L.

    1995-09-01

    Diverse and productive wetlands have resulted from coal mining in the midwest. The trend from surface to underground mining has increased the potential for subsidence. Planned subsidence of longwall mining areas provides increased opportunities for wetland habitat establishment. Planned subsidence over a 180 meter (590 foot) deep longwall mine in southern Illinois during 1984 to 1986 produced three subsidence wetlands totaling 15 hectares (38 acres). The resulting palustrine emergent wetlands enhanced habitat diversity within the surrounding palustrine forested unsubsided area. Habitat assessments and evaluations of avian utilization of the subsidence wetlands were conducted during February 1990 through October 1991. Avian utilization was greatest within the subsided wetlands. Fifty-three bird species representing seven foraging guilds utilized the subsidence wetlands. Wading/fishing, dabbling waterfowl, and insectivorous avian guilds dominated the subsidence wetlands. The subsidence wetlands represented ideal habitat for wood ducks and great blue herons which utilized snags adjacent to and within the wetlands for nesting (19 great blue heron nests produced 25 young). Dense cover and a rich supply of macroinvertebrates provide excellent brood habitat for wood ducks, while herpetofauna and ichthyofauna provided abundant forage in shallow water zones for great blue herons and other wetland wading birds. The diversity of game and non-game avifauna utilizing the subsidence areas demonstrated the unique value of these wetlands. Preplanned subsidence wetlands can help mitigate loss of wetland habitats in the midwest.

  19. NUTRIENT AND HABITAT INDICATORS FOR CRITERIA DEVELOPMENT IN GREAT LAKES COASTAL WETLANDS

    EPA Science Inventory

    EPA's Mid-Continent Ecology Division is testing indicators and establishing stressor - response relationships to support development of nutrient and habitat criteria for Great Lakes coastal wetlands. Our focus is on water quality changes, food web shifts, and vegetation loss as ...

  20. Mitigation bank promotes research on restoring Coastal Plain depression wetlands (South Carolina).

    SciTech Connect

    Barton, Christopher D.; DeSteven, Diane; Kilgo, John C.

    2004-12-31

    Barton, Christopher, D., Diane DeSteven and John C. Kilgo. 2004. Mitigation bank promotes research on restoring Coastal Plain depression wetlands (South Carolina). Ecol. Rest. 22(4):291-292. Abstract: Carolina bays and smaller depression wetlands support diverse plant communities and provide critical habitat for semi-aquatic fauna throughout the Coastal Plain region of the southeastern United States. Historically, many depression wetlands were altered or destroyed by surface ditching, drainage, and agricultural or silviculture uses. These important habitats are now at further risk of alteration and loss following a U.S. Supreme Court decision in 2001 restricting federal regulation of isolated wetlands. Thus, there is increased attention towards protecting intact sites and developing methods to restore others. The U.S. Department of Energy's (DOE) 312-mi2 (800-km2) Savannah River Site (SRS) in west-central South Carolina includes about 350 Carolina bays and bay-like wetland depressions, of which about two-thirds were degraded or destroyed prior to federal acquisition of the land. Although some of the altered wetlands have recovered naturally, others still have active active drainage ditches and contain successional forests typical of drained sites. In 1997, DOE established a wetland mitigation bank to compensate for unavoidable wetland impacts on the SRS. This effort provided an opportunity fir a systematic research program to investigate wetland restoration techniques and ecological responses. Consequently, research and management staffs from the USDA Forest Service, Westinghouse Savannah River Corporation, the Savannah River Technology Center, the Savannah River Ecology Laboratory (SREL) and several universities developed a collaborative project to restore degraded depression wetlands on the SRS. The mitigation project seeks cost-effective methods to restore the hydrology and vegetation typical of natural depression wetlands, and so enhance habitats for wetland

  1. Assessing coastal plain wetland composition using advanced spaceborne thermal emission and reflection radiometer imagery

    NASA Astrophysics Data System (ADS)

    Pantaleoni, Eva

    Establishing wetland gains and losses, delineating wetland boundaries, and determining their vegetative composition are major challenges that can be improved through remote sensing studies. We used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to separate wetlands from uplands in a study of 870 locations on the Virginia Coastal Plain. We used the first five bands from each of two ASTER scenes (6 March 2005 and 16 October 2005), covering the visible to the short-wave infrared region (0.52-2.185mum). We included GIS data layers for soil survey, topography, and presence or absence of water in a logistic regression model that predicted the location of over 78% of the wetlands. While this was slightly less accurate (78% vs. 86%) than current National Wetland Inventory (NWI) aerial photo interpretation procedures of locating wetlands, satellite imagery analysis holds great promise for speeding wetland mapping, lowering costs, and improving update frequency. To estimate wetland vegetation composition classes, we generated a classification and regression tree (CART) model and a multinomial logistic regression (logit) model, and compared their accuracy in separating woody wetlands, emergent wetlands and open water. The overall accuracy of the CART model was 73.3%, while for the logit model was 76.7%. The CART producer's accuracy of the emergent wetlands was higher than the accuracy from the multinomial logit (57.1% vs. 40.7%). However, we obtained the opposite result for the woody wetland category (68.7% vs. 52.6%). A McNemar test between the two models and NWI maps showed that their accuracies were not statistically different. We conducted a subpixel analysis of the ASTER images to estimate canopy cover of forested wetlands. We used top-of-atmosphere reflectance from the visible and near infrared bands, Delta Normalized Difference Vegetation Index, and a tasseled cap brightness, greenness, and wetness in linear regression model with canopy

  2. Modeling the suitability of potential wetland mitigation sites with a geographic information system.

    SciTech Connect

    Van Lonkhuyzen, R. A.; LaGory, K. E.; Kuiper, J. A.; Environmental Assessment

    2004-03-01

    Wetland mitigation is frequently required to compensate for unavoidable impacts to wetlands. Site conditions and landscape context are critical factors influencing the functions that created wetlands perform. We developed a spatial model and used a geographic information system (GIS) to identify suitable locations for wetland mitigation sites. The model used six variables to characterize site conditions: hydrology, soils, historic condition, vegetation cover, adjacent vegetation, and land use. For each variable, a set of suitability scores was developed that indicated the wetland establishment potential for different variable states. Composite suitability scores for individual points on the landscape were determined from the weighted geometric mean of suitability scores for each variable at each point. These composite scores were grouped into five classes and mapped as a wetland mitigation suitability surface with a GIS. Sites with high suitability scores were further evaluated using information on the feasibility of site modification and project cost. This modeling approach could be adapted by planners for use in identifying the suitability of locations as wetland mitigation sites at any site or region.

  3. Integration of multi-temporal spectral and structural information to map wetland vegetation in a brackish Connecticut marsh

    NASA Astrophysics Data System (ADS)

    Gilmore, M. S.; Wilson, E. H.; Barrett, N.; Civco, D. L.; Prisloe, S.; Hurd, J. D.; Chadwick, C.

    2008-12-01

    This study utilizes multitemporal QuickBird and single date LiDar canopy height data to classify the common plant communities of a tidal marsh at the mouth of the Connecticut River. A specific goal was to map the expanding distribution of non-native Phragmites australis (Cav.) Trin ex Steud (common reed), which has been outcompeting native species, particularly in disturbed marshes. P. australis spreads vigorously, forming dense monocultures that result in reduced biodiversity of plant, avian and macroinvertebrate species. We collected visible to near-infrared (VNIR) reflectance spectra of the dominant plant species S. patens (salt meadow grass), Typha spp. (cattail), and P. australis over two growing seasons to develop metrics that maximize phenological spectral and canopy height variability to distinguish these plants within a complex marsh community containing >100 plant species. Relative to other species, P. australis is best distinguished by its high NIR response and height late in the growing season. Typha spp. was well distinguished from other species by its high red/green ratio and S. patens by a unique green/blue ratio and low heights throughout the growing season. The field spectra and LiDar-derived heights were used to guide an object-oriented classification methodology using multitemporal QuickBird data collected over the same time interval as the field spectra. The classification was validated using a field inventory of marsh vegetation. Overall maximum fuzzy accuracy for the classification was 97% for Phragmites, 63% for Typha spp. and 80% for S. patens meadows; this improved to 97%, 76%, and 92%, respectively, using a fuzzy acceptable match measure. Image acquisition timing was critical for the identification of targeted plant species in this heterogeneous marsh. These datasets and protocols may provide coastal resource managers, municipal officials and researchers a set of recommended guidelines for remote sensing data collection for marsh inventory

  4. Establishing quantitative relations between mammalian communities, climate regimes, and vegetation density - A diversity-based reference model and case study

    NASA Astrophysics Data System (ADS)

    Hertler, Christine; Wolf, Dominik; Bruch, Angela; Märker, Michael

    2013-04-01

    A considerable diversity of hominin taxa is described from the Pleistocene of sub-Saharan Africa. Inner-African range expansions of these taxa are primarily addressed by morphological comparisons of the hominin specimens and systematic interpretation of the results. Considering hominin expansion patterns as being at least co-determined by ecology and environment requires an assessment of respective features of paleo-communities as well as features of the environments with which they are associated. Challenges in validation and integration of reconstructions of hominin environments and ecologies can be met with well-organized recent reference models. Modelling the present day situation permits to assess relevant variables and to establish interactions among them on a quantitative basis. In a next step such a model can be applied to classify hominin paleoenvironments, for which not all data sources are available. An example for this approach is introduced here. In order to characterize hominin environments in sub-Saharan Africa, we assessed sets of variables for composition, structure and diversity of the large mammal communities, climate (temperature and precipitation), and vegetation in African national parks. These data are applied to analyse correlations between faunal communities and their environments on a quantitative basis. While information on large mammal communities is frequently available for hominin localities and regional climate features are addressed on the basis of abiotic proxies, information on paleoflora and vegetation is mostly lacking for the Plio-Pleistocene in sub-Saharan Africa. A quantitative reference model therefore offers new options for reconstructions. A recent reference model moreover permits to quantify descriptive terms like 'savanna'. We will introduce a reference model for sub-Saharan Africa and demonstrate its application in the reconstruction of hominin paleoenvironments. The corresponding quantitative characterization of

  5. HYDROMORPHIC DETERMINANTS OF AQUATIC HABITAT VARIABILITY IN LAKE SUPERIOR COASTAL WETLANDS

    EPA Science Inventory

    This manuscript evaluates patterns in water quality, water movement, substrate, and vegetation in 10 Lake Superior coastal wetlands in light of wetland hydrology and morphology. Water quality, substrate, and vegetation structure are important aspects of habitat for fishes that u...

  6. The importance of subsurface geology for water source and vegetation communities in Cherokee Marsh, Wisconsin

    USGS Publications Warehouse

    Kurtz, A.M.; Bahr, J.M.; Carpenter, Q.J.; Hunt, R.J.

    2007-01-01

    Restoration of disturbed wetland systems is an important component of wetland mitigation, yet uncertainty remains about how hydrologic processes affect biologic processes and wetlands patterns. To design more effective restoration strategies and re-establish native plant communities in disturbed wetlands, it is imperative to understand undisturbed systems. A site within Cherokee Marsh located in Madison, Wisconsin, USA, contains a relatively undisturbed area of wetland consisting of plant communities common within the prairie landscape including a fen, sedge meadow, and shallow marsh. These distinct communities are found within an area of minimal topographic relief, yet transitions from one community to the next occur over short distances. This study sought to characterize the geologic, hydrologic, and chemical gradients associated with these shifts in vegetation to gain insight into the factors controlling the spatial differences in dominant plant species, which could be critical for restoration success. Vegetation analyses revealed a transition of dominant sedge species, which appeared to correspond to changes in hydrology from a ground-water dominated to a surface-water dominated system (as determined by water isotopes). Along the same vegetation transect, subsurface coring results show a heterogeneous composition of peat and till with lateral and vertical variations in stratigraphy, which relates to variability in ground-water discharge as evidenced by hydroperiods and stable isotope composition. Applications of this type of approach throughout the glaciated terrains of the midwestern and northeastern United States and Canada can improve future wetland restoration and management. ?? 2007, The Society of Wetland Scientists.

  7. A Study of Natural and Restored Wetland Hydrology

    USGS Publications Warehouse

    Bayless, E. Randall; Arihood, Leslie D.; Sidle, William C.; Pavlovic, Noel B.

    1999-01-01

    The U.S. Geological Survey and the U.S. Environmental Protection Agency are jointly studying the hydrology of a long-existing natural wetland and a recently restored wetland in the Kankakee River Valley in northwestern Indiana. In characterizing the two wetlands, project investigators are testing innovative methods to identify the analytical tools best suited for evaluating the success of wetland restoration. Investigators also are examining and comparing the relations between hydrology and restored wetland vegetation.

  8. Restoring biodiversity in the Gwydir Wetlands through environmental flows.

    PubMed

    Mawhinney, W A

    2003-01-01

    As part of the Water Reforms process, environmental flow rules have been progressively implemented in New South Wales rivers. The Integrated Monitoring of Environmental Flows (IMEF) is a major project established to better understand how rivers and associated wetlands respond to environmental water allocations. The results presented here represent the vegetation data collected for the testing of the hypothesis that "protecting or restoring a portion of freshes and high flows and otherwise maintaining natural flow variability will replenish anabranches and riverine wetlands, restoring their biodiversity". The study site is the Ramsar listed Gwydir Wetlands, located on the Gingham and Gwydir (Big Leather) Watercourses in the Lower Gwydir Valley, 100 km west of Moree. The expansion of irrigated agriculture in the lower Gwydir valley has severely altered flow regimes in the wetlands. The spread of the weed Phyla canescens (Lippia) is of major concern to landholders in the Gwydir Wetlands. Results indicate that Paspalum distichum (Water couch) and Eleocharis plana (Ribbed spike-rush) can maintain dominance over Phyla canescens if flooding occurs on a semi-regular basis. Conversely, Eichhornia crassipes (Water hyacinth) is a rampant noxious weed of open water in the Gwydir Wetlands, and has quickly spread in areas that are inundated for long periods. Management of this weed requires periodic drying of the wetlands to cause desiccation and death of the plants. The flooding requirement of individual species and plant associations in the Gwydir Wetlands are currently not fully understood. By providing better information on the consequence of different flows, the IMEF project will help to develop better management strategies to shift the dominance from introduced species such as P. canescens and E. crassipes to more desirable native plant species. PMID:14653636

  9. Chemical Properties of Pore Water and Sediment at Three Wetland Sites Near the F- and H-Area Seepage Basins, Savannah River Site

    SciTech Connect

    Friday, G.P.

    2001-05-15

    In 1980, vegetative stress and arboreal mortality in wetland plant communities down-gradient from the F- and H-Area seepage basins were detected using aerial imagery. By 1988, approximately six acres in H-Area and four acres in F-Area had been adversely impacted. Today, wetland plant communities have become well established at the H-Area tree-kill zone.

  10. Wetlands for Wastewater Treatment.

    PubMed

    Jiang, Yi; Martinez-Guerra, Edith; Gnaneswar Gude, Veera; Magbanua, Benjamin; Truax, Dennis D; Martin, James L

    2016-10-01

    An update on the current research and development of the treatment technologies, which utilize natural processes or passive components in wastewater treatment, is provided in this paper. The main focus is on wetland systems and their applications in wastewater treatment (as an advanced treatment unit or decentralized system), nutrient and pollutant removal (metals, industrial and emerging pollutants including pharmaceutical compounds). A summary of studies involving the effects of vegetation, wetland design and modeling, hybrid and innovative systems, storm water treatment and pathogen removal is also included. PMID:27620086

  11. Wetland InSAR

    NASA Astrophysics Data System (ADS)

    Wdowinski, S.; Kim, S.; Amelung, F.; Dixon, T.

    2006-12-01

    Wetlands are transition zones where the flow of water, the nutrient cycling, and the sun energy meet to produce a unique and very productive ecosystem. They provide critical habitat for a wide variety of plant and animal species, including the larval stages of many ocean fish. Wetlands also have a valuable economical importance, as they filter nutrients and pollutants from fresh water used by human and provide aquatic habitats for outdoor recreation, tourism, and fishing. Globally, many such regions are under severe environmental stress, mainly from urban development, pollution, and rising sea level. However, there is increasing recognition of the importance of these habitats, and mitigation and restoration activities have begun in a few regions. A key element in wetlands conservation, management, and restoration involves monitoring its hydrologic system, as the entire ecosystem depends on its water supply. Heretofore, hydrologic monitoring of wetlands are conducted by stage (water level) stations, which provide good temporal resolution, but suffer from poor spatial resolution, as stage station are typically distributed several, or even tens of kilometers, from one another. Wetland application of InSAR provides the needed high spatial resolution hydrological observations, complementing the high temporal resolution terrestrial observations. Although conventional wisdom suggests that interferometry does not work in vegetated areas, several studies have shown that both L- and C-band interferograms with short acquisition intervals (1-105 days) can maintain excellent coherence over wetlands. In this study we explore the usage of InSAR for detecting water level changes in various wetland environments around the world, including the Everglades (south Florida), Louisiana Coast (southern US), Chesapeake Bay (eastern US), Pantanal (Brazil), Okavango Delta (Botswana), and Lena Delta (Siberia). Our main study area is the Everglades wetland (south Florida), which is covered by

  12. A Study on Effect of Water Background on Canopy Spectral of Wetland Aquatic Plant.

    PubMed

    Liu, Guang; Tang, Peng; Cai Zhan-qing; Wang, Tian-tian; Xu, Jun-feng

    2015-10-01

    Aquatic vegetation is the core of the wetland ecosystem, and it's also the main factor influencing the wetland ecosystem functions. In recent years, satellite remote sensing technology has been widely used in the investigation, classification and protection fields of wetland vegetation resources. Because of its unique growth environment, aquatic vegetation, the canopy spectrum of aquatic vegetation will be affected by water background elements including air-water interface, plankton in the water, sediment content, transparency, water depth, sediment, and the other optically active ingredients. When the remote sensing technology for wetland aquatic vegetation canopy spectral studies, should be considered the growth environment differences between aquatic and terrestrial vegetation. However, previous studies did not get the attention it deserves. This paper choose a typical water plant (Iris tentorium Maxim) as the research object, simulate the growth environment of wetland aquatic plants, use the feature spectrometer measurements the spectral reflectance of Iris tentorium Maxim vegetation canopy under different water depth gradient background (400-2 400 nm). Experimental results show that there is a significant negative correlation between background water depth and Iris canopy reflectance. Visible light band absolute correlation coefficient is above 0.9, near infrared band absolute correlation coefficient is above 0.8. In visible light and near infrared band, with water depth increases, the Iris canopy reflectance decreases obviously. Finally based on the highest correlation band of visible light and near infrared region (505, 717, 1 075 and 2 383 nm) established the linear equation between background water depth and the canopy reflectance, obtained the related parameters. PMID:26904852

  13. Reconstruction of Anacostia wetlands: success?

    USGS Publications Warehouse

    Hammerschlag, R.S.

    2002-01-01

    . Revegetation, which is a product of direct plantings (16 species comprised of 350,000 plants) and by establishment of volunteer plants, must be considered successful. Remarkably, full vegetation cover was achieved by the end of the first year (1993). Species diversity is high with 100-130 wetland species occupying portions of the wetland. Good species differentiation (incipient plant communities) can be noted at areas of sediment elevation differences. There is a good range of predominant species (five to eight) with rice cutgrass (Leersia oryzoides) initially being dominant but in later years becoming codominant. Even the native wild rice (Zizania aquatica) is making a substantive comeback. Invasive plants such as purple loosestrife (Lythrum salicaria) and phragmites (Phragmites australis) are being watched and dealt with as appropriate. There has been important habitat creation, and a resulting increase in fauna can be expected, particularly as the acreage reconstructed at Kenilworth has more than doubled with similarly reconstructed wetlands at Kingman Lake (42 acres), which were completed during the summer of 2000, just a quarter of a mile down river. One of the challenges with the Kingman marsh reconstruction has been protecting against the grazing pressure of native Canada geese (Branm canadensis). In the long run, these revived Anacostia wetlands are bound to improve local conditions and will contribute to a rejuvenated Chesapeake Bay system.

  14. Wetland Mitigation Monitoring at the Fernald Preserve - 13200

    SciTech Connect

    Powell, Jane; Bien, Stephanie; Decker, Ashlee; Homer, John; Wulker, Brian

    2013-07-01

    The U.S. Department of Energy is responsible for 7.2 hectares (17.8 acres) of mitigation wetland at the Fernald Preserve, Ohio. Remedial activities affected the wetlands, and mitigation plans were incorporated into site-wide ecological restoration planning. In 2008, the Fernald Natural Resource Trustees developed a comprehensive wetland mitigation monitoring approach to evaluate whether compensatory mitigation requirements have been met. The Fernald Preserve Wetland Mitigation Monitoring Plan provided a guideline for wetland evaluations. The Ohio Environmental Protection Agency (Ohio EPA) wetland mitigation monitoring protocols were adopted as the means for compensatory wetland evaluation. Design, hydrologic regime, vegetation, wildlife, and biogeochemistry were evaluated from 2009 to 2011. Evaluations showed mixed results when compared to the Ohio EPA performance standards. Results of vegetation monitoring varied, with the best results occurring in wetlands adjacent to forested areas. Amphibians, particularly ambystomatid salamanders, were observed in two areas adjacent to forested areas. Not all wetlands met vegetation performance standards and amphibian biodiversity metrics. However, Fernald mitigation wetlands showed substantially higher ratings compared to other mitigated wetlands in Ohio. Also, soil sampling results remain consistent with other Ohio mitigated wetlands. The performance standards are not intended to be 'pass/fail' criteria; rather, they are reference points for use in making decisions regarding future monitoring and maintenance. The Trustees approved the Fernald Preserve Wetland Mitigation Monitoring Report with the provision that long-term monitoring of the wetlands continues at the Fernald Preserve. (authors)

  15. Ecohydraulics and Estuarine Wetland Rehabilitation

    NASA Astrophysics Data System (ADS)

    Rodriguez, J. F.; Howe, A.; Saintilan, N.; Spencer, J.

    2004-12-01

    The hydraulics or water flow in wetlands is known to be a key factor influencing ecosystem development in estuarine wetland environments. The relationship is indirect, with the hydraulics of wetlands influencing a host of factors including soil salinity, waterlogging, sediment transport, sediment chemistry, vegetation dispersal and growth and nutrient availability and cycling. The relationship is also not one way, with the hydraulics of wetlands being influenced by plant and animal activity. Understanding these complex interactions is fundamental for the adequate management of estuarine wetlands. Listed as a Wetland of International Importance under the 1971 Ramsar Convention, the Hunter River estuary is regarded as the most significant site for migratory shorebirds in New South Wales, Australia. Over the past 20 years, the number of migratory shorebirds in the estuary has sharply declined from 8,000 to 4,000 approx. Alteration of bird habitat is believed to be one of the reasons for this alarming trend. In 2004 we started a three-year program to investigate the links between hydraulics, sediment, benthic invertebrates, vegetation and migratory shorebird habitat in the estuary. During the first year we have focused on a highly disturbed part of the Hunter estuary wetlands located on Ash Island. The area is one of the major roosting sites in the estuary and is characterized by a complex hydraulic regime due to a restricted tidal interchange with the Hunter River and the presence of infrastructure for the maintenance of power lines (i.e., roads, bridges, culverts). Salt marshes, mudflat and mangroves are the dominant vegetation types. The monitoring program includes measurements of water levels, salinity, discharge, velocity, turbulence, sediment transport and deposition, plant species and density, soil composition and benthic invertebrates coordinated with observations of bird habitat utilization on a number of locations throughout the wetland and for different flow

  16. Influence of wetland type, hydrology, and wetland destruction on aquatic communities within wetland reservoir subirrigation systems in northwestern Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Establishment of an agricultural water recycling system known as the wetland reservoir subirrigation system (WRSIS) results in the creation of two different types of wetlands adjacent to agricultural fields. Each WRSIS consists of one treatment wetland designed to process agricultural contaminants (...

  17. Windows of opportunity for salt marsh vegetation establishment on bare tidal flats: The importance of temporal and spatial variability in hydrodynamic forcing

    NASA Astrophysics Data System (ADS)

    Hu, Zhan; Belzen, Jim; Wal, Daphne; Balke, Thorsten; Wang, Zheng Bing; Stive, Marcel; Bouma, Tjeerd J.

    2015-07-01

    Understanding the mechanisms limiting and facilitating salt marsh vegetation initial establishment is of widespread importance due to the many valuable services salt marsh ecosystems offer. Salt marsh dynamics have been investigated by many previous studies, but the mechanisms that enable or disable salt marsh initial establishment are still understudied. Recently, the "windows of opportunity" (WoO) concept has been proposed as a framework providing an explanation for the initial establishment of biogeomorphic ecosystems and the role of physical disturbance herein. A WoO is a sufficiently long disturbance-free period following seedling dispersal, which enables successful establishment. By quantifying the occurrence of WoO, vegetation establishment pattern can be predicted. For simplicity sake and as prove of concept, the original WoO framework considers tidal inundation as the only physical disturbance to salt marsh establishment, whereas the known disturbance from tidal currents and wind waves is ignored. In this study, we incorporate hydrodynamic forcing in the WoO framework. Its spatial and temporal variability is considered explicitly in a salt marsh establishment model. We used this model to explain the observed episodic salt marsh recruitment in the Westerschelde Estuary, Netherlands. Our results reveal that this model can significantly increase the spatial prediction accuracy of salt marsh establishment compared to a model that excludes the hydrodynamic disturbance. Using the better performing model, we further illustrate how tidal flat morphology determines salt marsh establishing elevation and width via hydrodynamic force distribution. Our model thus offers a valuable tool to understand and predict bottlenecks of salt marsh restoration and consequences of changing environmental conditions due to climate change.

  18. Climate Change and Intertidal Wetlands

    PubMed Central

    Ross, Pauline M.; Adam, Paul

    2013-01-01

    Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause—the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the “squeeze” experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change. PMID:24832670

  19. What Are Wetlands are Where Are They?

    NASA Astrophysics Data System (ADS)

    Matthews, E.

    2011-12-01

    The first empirical models of methane emission from natural wetlands were developed in the late 1980s and early 1990s following the first field measurements of wetland methane fluxes. Since the mid-1990s, a suite of empirical, ecosystem, and process-based models of increasing complexity have been developed to simulate methane emissions from wetlands. Inputs to these models typically include climate variables, and vegetation and soil characteristics; they simulate soil temperature/thaw, water-table position, carbon supply and processes of production, transport, oxidation and emission of methane. A standard approach has been to apply the CH4 models to an externally-defined wetland data set due to the difficulty of modeling the distribution of wetlands themselves. More recently, researchers have begun characterizing methane-producing environments based on, inter alia, modeled soil hydrological dynamics and satellite-derived surface inundation. However, modeling the distribution and dynamics of methane-producing wetlands remains a fundamental challenge in understanding the role of wetlands in the global methane cycle under past, current and future climates. The wide spectrum of vegetation, hydrological regime, chemistry, soils, and seasonality means that defining wetlands is not straightforward and, although multiple systems describing local and regional wetland environments exist, none encompasses their global diversity particularly with regard to methane-relevant characteristics. Recent work by Petrescu et al. (Glob. Biogeochem. Cycl., 24/4, 2010) highlights the sensitivity of modeled emissions to uncertainties in wetland distributions. We hypothesize that differences among wetland distributions can be explained primarily by the methods, purposes and instruments used to produce the distributions. The lack of a comprehensive definition of wetlands for methane studies, together with approaches with different strengths and weaknesses for identifying the spectrum of

  20. Control of hardwood regeneration in restored carolina bay depression wetlands.

    SciTech Connect

    Moser, Lee, J.; Barton, Christopher, D.; Blake, John, I.

    2012-06-01

    Carolina bays are depression wetlands located in the coastal plain region of the eastern United States. Disturbance of this wetland type has been widespread, and many sites contain one or more drainage ditches. Restoration of bays is of interest because they are important habitats for rare flora and fauna. Previous bay restoration projects have identified flood-tolerant woody competitors in the seedbank and re-sprouting as impediments to the establishment of desired herbaceous wetland vegetation communities. We restored 3 bays on the Savannah River Site, South Carolina, by plugging drainage ditches, harvesting residual pine/hardwood stands within the bays, and monitoring the vegetative response of the seedbank to the hydrologic change. We applied a foliar herbicide on one-half of each bay to control red maple (Acerrubrum), sweetgum (Liquidambar styraciflua), and water oak (Quercus nigra) sprouting, and we tested its effectiveness across a hydrologic gradient in each bay. Hardwood regeneration was partially controlled by flooding in bays that exhibited long growing season hydroperiods. The findings also indicated that herbicide application was an effective means for managing hardwood regeneration and re-sprouting in areas where hydrologic control was ineffective. Herbicide use had no effect on species richness in the emerging vegetation community. In late-season drawdown periods, or in bays where hydroperiods are short, more than one herbicide application may be necessary.

  1. Hydrologic changes and processes underlying recent wetland loss in Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Schook, D. M.; Cooper, D. J.

    2011-12-01

    Wetlands are some of the most biologically productive yet vulnerable ecosystems on Earth. They provide essential habitat for various biota and act as landscape indicators by reflecting the status of catchment-scale processes. The drying and shrinking of wetlands during the past four decades in Yellowstone National Park's Northern Range has recently incited concern among National Park managers and the public at large. Investigation of wetland hydrologic regime is a critical step in building an understanding of these changing ecosystems. Our research has the following objectives: (1) Classify wetlands according to their particular hydrologic function, including climatic and geomorphic processes supporting them, (2) Determine the patterns and magnitude of water level declines that occurred during the late 20th and early 21st centuries and assess whether these fall within the natural range of variation, (3) More closely examine a focal site that has experienced dramatically reduced water levels to gain a more refined understanding of wetland processes. In 2009 we established a monitoring network of 24 wetlands within the Northern Range. Each wetland was instrumented with 4 to 6 shallow groundwater well and piezometer nests. Well data was manually collected from each site at one to two week intervals in summers 2009 and 2010. Data analyses indicate that the study sites represent locations of ground water discharge, recharge, and flow-through, as well as sites perched above the regional water table. We classified wetlands into 7 groups using a hydrograph shape-magnitude framework previously used in stream systems. Climatic data reveal that hydrologic conditions occurring in the recent past are within the range of historic variation, but that we are in a drier than average period. Aerial photographs and wetland soil delineation both reveal greater wetland extent in the past 50 years, and these conditions are linked to the environmental setting of each wetland. Wetland

  2. Uptake of /sup 226/Ra by established vegetation and black cutworm larvae, Agrotis ipsilon (class Insecta: order Lepidoptera), on U mill tailings at Elliot Lake, Canada

    SciTech Connect

    Clulow, F.V.; Dave, N.K.; Lim, T.P.; Cloutier, N.R.

    1988-07-01

    Radium-226 levels in samples from an inactive U tailings site at Elliot Lake, Ontario, Canada, were: 9140 +/- 500 mBq g-1 dry weight in the substrate; 62 +/- 1 mBq g-1 dry weight in rye, Secale cereale, and less than 3.7 mBq g-1 dry weight in oats, Avena sativa, the dominant species established by revegetation of the tailings; and 117 +/- 7 mBq g-1 dry weight in washed and unwashed black cutworm larvae. Concentration ratios were: vegetation to tailings 0.001-0.007; black cutworms to vegetation 3.6 and black cutworms to tailings 0.01. The values are considered too low to be considered a hazard to herring gulls, Larus argentatus, which occasionally feed on cutworms.

  3. Methane Fluxes from Subtropical Wetlands

    NASA Astrophysics Data System (ADS)

    DeLucia, N.; Gomez-Casanovas, N.; Bernacchi, C.

    2013-12-01

    It is well documented that green house gas concentrations have risen at unequivocal rates since the industrial revolution but the disparity between anthropogenic sources and natural sources is uncertain. Wetlands are one example of a natural ecosystem that can be a substantial source or sink for methane (CH4) depending on climate conditions. Due to strict anaerobic conditions required for CH4-generating microorganisms, natural wetlands are one of the main sources for biogenic CH4. Although wetlands occupy less than 5% of total land surface area, they contribute approximately 20% of total CH4 emissions to the atmosphere. The processes regulating CH4 emissions are sensitive to land use and management practices of areas surrounding wetlands. Variation in adjacent vegetation or grazing intensity by livestock can, for example, alter CH4 fluxes from wetland soils by altering nutrient balance, carbon inputs and hydrology. Therefore, understanding how these changes will affect wetland source strength is essential to understand the impact of wetland management practices on the global climate system. In this study we quantify wetland methane fluxes from subtropical wetlands on a working cattle ranch in central Florida near Okeechobee Lake (27o10'52.04'N, 81o21'8.56'W). To determine differences in CH4 fluxes associated with land use and management, a replicated (n = 4) full factorial experiment was designed for wetlands where the surrounding vegetation was (1) grazed or un-grazed and (2) composed of native vegetation or improved pasture. Net exchange of CH4 and CO2 between the land surface and the atmosphere were sampled with a LICOR Li-7700 open path CH4 analyzer and Li-7500A open path CO2/H20 analyzer mounted in a 1-m3 static gas-exchange chamber. Our results showed and verified that CH4 emissions from subtropical wetlands were larger when high soil moisture was coupled with high temperatures. The presence of cattle only amplified these results. These results help quantify

  4. Identification and characterization of wetlands in the Bear Creek watershed

    SciTech Connect

    Rosensteel, B.A.; Trettin, C.C.

    1993-10-01

    The primary objective of this study was to identify, characterize, and map the wetlands in the Bear Creek watershed. A preliminary wetland categorization system based on the Cowardin classification system (Cowardin et al. 1979) with additional site-specific topographic, vegetation, and disturbance characteristic modifiers was developed to characterize the type of wetlands that exist in the Bear Creek watershed. An additional objective was to detect possible relationships among site soils, hydrology, and the occurrence of wetlands in the watershed through a comparison of existing data with the field survey. Research needs are discussed in the context of wetland functions and values and regulatory requirements for wetland impact assessment and compensatory mitigation.

  5. Role of vegetation (Typha latifolia) on nutrient removal in a horizontal subsurface-flow constructed wetland treating UASB reactor-trickling filter effluent.

    PubMed

    da Costa, Jocilene Ferreira; Martins, Weber Luiz Pinto; Seidl, Martin; von Sperling, Marcos

    2015-01-01

    The main objective of the work is to characterize the role of plants in a constructed wetland in the removal of nitrogen (N) and phosphorus (P). The experiments were carried out in a full-scale system in the city of Belo Horizonte, Brazil, with two parallel horizontal subsurface-flow constructed wetland units (one planted with Typha latifolia and one unplanted) treating the effluent from a system composed of an upflow anaerobic sludge blanket reactor and a trickling filter (TF). Each wetland unit received a mean flow of approximately 8.5 m³ d⁻¹ (population equivalent around 60 inhabitants each), with a surface hydraulic loading rate 0.12 m³m⁻²d⁻¹. The experiments were conducted from September 2011 to July 2013. Mean effluent concentrations from the wetlands were: (a) planted unit total nitrogen (TN) 22 mg L⁻¹, ammonia-N 19 mg L⁻¹, nitrite-N 0.10 mg L⁻¹, nitrate-N 0.25 mg L⁻¹, P-total 1.31 mg L⁻¹; and (b) unplanted unit TN 24 mg L⁻¹, ammonia-N 20 mg L⁻¹, nitrite-N 0.54 mg mL⁻¹, nitrate-N 0.15 mg L⁻¹, P-total 1.31 mg L⁻¹. The aerial part of the plant contained mean values of 24.1 gN (kg dry matter)⁻¹ and 4.4 gP (kg dry matter)⁻¹, and the plant root zone was composed of 16.5 gN (kg dry matter)⁻¹ and 4.1 gP (kg dry matter)⁻¹. The mean extraction of N by the plant biomass was 726 kgN ha⁻¹y⁻¹, corresponding to 17% of the N load removed. For P, the extraction by the plant biomass was 105 kgP ha⁻¹y⁻¹, corresponding to 9% of the P load removed. These results reinforce the reports that N and P removal due to plant uptake is a minor mechanism in horizontal subsurface-flow constructed wetlands operating under similar loading rates, typical for polishing of sanitary effluent. PMID:25860702

  6. Productivity of wet soils: Biomass of cultivated and natural vegetation

    SciTech Connect

    Johnston, C.A.

    1988-12-01

    Wet soils, soils which have agronomic limitations because of excess water, comprise 105 million acres of non-federal land in the conterminous United States. Wet soils which support hydrophytic plants are ''wetlands'', and are some of the most productive natural ecosystems in the world. When both above- and belowground productivity are considered, cattail (Typha latifolia) is the most productive temperate wetland species (26.4 Mg/ha/year). Both cattail and reed (Phragmites australis) have aboveground productivities of about 13 Mg/ha/year. Although average aboveground yields of reed canarygrass (Phalaris arundinacea) are lower (9.5 Mg/ha/year), techniques for its establishment and cultivation are well-developed. Other herbaceous wetland species which show promise as biomass crops include sedge (Carex spp.), river bulrush (Scirpus fluviatilis) and prairie cordgrass (Spartina pectinata). About 40% of wet soils in the conterminous US are currently cultivated, and they produce one-quarter of the major US crops. Most of this land is artificially drained for crops such as corn, soybeans, and vegetables. US wetlands are drained for agriculture at the rate of 223,000 ha/yr. Paddies flooded with water are used to grow rice, cranberries, and wild rice. Forage and live sphagnum moss are products of undrained wetlands. A number of federal and state regulations apply to the draining or irrigation of wetlands, but most do not seriously restrict their use for agriculture. 320 refs., 36 tabs.

  7. Freshwater Wetlands.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

    Provides descriptions about freshwater wetlands, such as marshes, swamps, and bogs. Contains three learning activities which deal with unusual wetland plants, the animals and plants in a typical marsh, and the effects of a draught on a swamp. Included are reproducible handouts and worksheets for two of the activities. (TW)

  8. Differences in Aquatic Communities Between Wetlands Created by an Agricultural Water Recycling System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Establishment of an agricultural water recycling system known as the wetland reservoir subirrigation system (WRSIS) results in the creation of wetlands adjacent to agricultural fields. Each WRSIS consists of one wetland designed to process agricultural chemicals (WRSIS wetlands) and one wetland to s...

  9. ERTS-1 investigation of wetlands ecology

    NASA Technical Reports Server (NTRS)

    Anderson, R. R. (Principal Investigator); Carter, V.; Mcginness, J.

    1975-01-01

    The author has identified the following significant results. Data from aircraft can be used for large scale mapping where detailed information is necessary, whereas Landsat-1 data are useful for rapid mapping of gross wetland boundaries and vegetative composition and assessment of seasonal change plant community composition such as high and low growth forms of Spartina alterniflora, Juncus roemarianus, and Spartina cynosuroides. Spoil disposal and wetland ditching activities may also be defined. Wetland interpretation is affected by tidal stage; drainage patterns are more easily detected at periods of low water. Species discrimination is easier at periods of high water during the growing season; upper wetland boundaries in fresh water tidal marshes are more easily delineated during the winter months when marsh vegetation is largely dead or dormant. Fresh water discharges from coastal streams may be inferred from the species composition of contiguous wetlands.

  10. Remote sensing of coastal wetlands

    NASA Technical Reports Server (NTRS)

    Hardisky, M. A.; Klemas, V.; Gross, M. F.

    1986-01-01

    Various aircraft and satellite sensors for detecting and mapping wetlands properties are examined. The uses of color IR photography to map coastal vegetation, and of Landsat MSS and TM and SPOT data to quantify biomass and productivity for large wetland areas are discussed. For spectral estimation of biomass and productivity, the relation between radiance and biomass needs to be studied; the quantity and orientation of dead biomass and the amount of soil reflectance in comparison with vegetation reflectance in a given target area affect the spectral estimation of biomass. The radiometric evaluation of brackish wetland, and remote sensing in mangroves are described. The collection of images in narrow, contiguous spectral band using imaging spectrometry is considered.