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Sample records for meadows meadow creek

  1. Restore McComas Meadows; Meadow Creek Watershed, 2004-2005 Annual Report.

    SciTech Connect

    McRoberts, Heidi

    2005-12-01

    The Nez Perce Tribe Department of Fisheries Resource Management, Watershed Division approaches watershed restoration with a ridge-top to ridge-top approach. Watershed restoration projects within the Meadow Creek watershed are coordinated and cost shared with the Nez Perce National Forest. The Nez Perce Tribe began watershed restoration projects within the Meadow Creek watershed of the South Fork Clearwater River in 1996. Progress has been made in restoring the watershed by excluding cattle from critical riparian areas through fencing, planting trees in riparian areas within the meadow and its tributaries, prioritizing culverts for replacement to accommodate fish passage, and decommissioning roads to reduce sediment input. During this contract period, bids were solicited and awarded for two culvert replacement projects on Doe Creek, and a tributary to Meadow Creek. Additionally, NEPA and permits were completed for the ditch restoration project within McComas Meadows. Due to delays in cultural resource surveys, the contract was not awarded for the performance of the ditch restoration. It will occur in 2005. Monitoring for project effectiveness and trends in watershed conditions was also completed. Road decommissioning monitoring, as well as stream temperature, sediment, and discharge were completed.

  2. Restore McComas Meadows; Meadow Creek Watershed, 2005-2006 Annual Report.

    SciTech Connect

    McRoberts, Heidi

    2006-07-01

    The Nez Perce Tribe Department of Fisheries Resource Management, Watershed Division approaches watershed restoration with a ridge-top to ridge-top approach. Watershed restoration projects within the Meadow Creek watershed are coordinated and cost shared with the Nez Perce National Forest. The Nez Perce Tribe began watershed restoration projects within the Meadow Creek watershed of the South Fork Clearwater River in 1996. Progress has been made in restoring the watershed by excluding cattle from critical riparian areas through fencing, planting trees in riparian areas within the meadow and its tributaries, prioritizing culverts for replacement to accommodate fish passage, and decommissioning roads to reduce sediment input. During this contract period work was completed on two culvert replacement projects; Doe Creek and a tributary to Meadow Creek. Additionally construction was also completed for the ditch restoration project within McComas Meadows. Monitoring for project effectiveness and trends in watershed conditions was also completed. Road decommissioning monitoring, as well as stream temperature, sediment, and discharge were completed.

  3. Restore McComas Meadows; Meadow Creek Watershed, 2003-2004 Annual Report.

    SciTech Connect

    McRoberts, Heidi

    2006-08-01

    The Nez Perce Tribe Department of Fisheries Resource Management, Watershed Division approaches watershed restoration with a ridge-top to ridge-top approach. Watershed restoration projects within the Meadow Creek watershed are coordinated and cost shared with the Nez Perce National Forest. The Nez Perce Tribe began watershed restoration projects within the Meadow Creek watershed of the South Fork Clearwater River in 1996. Progress has been made in restoring the watershed by excluding cattle from critical riparian areas through fencing, planting trees in riparian areas within the meadow and its tributaries, prioritizing culverts for replacement to accommodate fish passage, and decommissioning roads to reduce sediment input. Designs for culvert replacements are being coordinated with the Nez Perce National Forest. 20 miles of roads were decommissioned. Tribal crews completed maintenance to the previously built fence.

  4. Restore McComas Watershed; Meadow Creek Watershed, 2002-2003 Annual Report.

    SciTech Connect

    McRoberts, Heidi

    2004-01-01

    The Nez Perce Tribe Department of Fisheries Resource Management, Watershed Division approaches watershed restoration with a ridge-top to ridge-top approach. Watershed restoration projects within the Meadow Creek watershed are coordinated with the Nez Perce National Forest. The Nez Perce Tribe began watershed restoration projects within the Meadow Creek watershed of the South Fork Clearwater River in 1996. Progress has been made in restoring the watershed by excluding cattle from critical riparian areas through fencing. During years 2000-2003, trees were planted in riparian areas within the meadow and its tributaries. Culverts have been prioritized for replacement to accommodate fish passage throughout the watershed. Designs for replacement are being coordinated with the Nez Perce National Forest. Twenty miles of road were contracted for decommissioning. Tribal crews completed maintenance to the previously built fence.

  5. 18. AHWAHNEE MEADOW. SOUTHSIDE DRIVE AT BOTTOM OF MEADOW AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. AHWAHNEE MEADOW. SOUTHSIDE DRIVE AT BOTTOM OF MEADOW AND AHWAHNEE ROAD AT TOP OF MEADOW. NOTE OLD ROAD ALIGNMENT AT EAST EDGE OF MEADOW. - Yosemite National Park Roads & Bridges, Yosemite Village, Mariposa County, CA

  6. Geologic characteristics and movement of the Meadow Creek landslide, part of the Coal Hill landslide complex, western Kane County, Utah

    USGS Publications Warehouse

    Ashland, Francis X.; McDonald, Greg N.; Carney, Stephanie M.; Tabet, David E.; Johnson, Cari L.

    2010-01-01

    The Meadow Creek landslide, part of the Coal Hill landslide complex in western Kane County, Utah, is about 1.7 miles (2.7 km) wide and 1.3 miles (2.1 km) long and contains six smaller historical slides. The upper part of the Meadow Creek landslide is gently sloping and consists of displaced and back-rotated blocks of Cretaceous Dakota and Cedar Mountain Formations that form northeast- to locally east-trending ridges that are separated by sediment-filled half-grabens. The lower part of the landslide is gently to moderately sloping, locally incised, and consists of heterogeneous debris that overrides the Jurassic Carmel Formation near Meadow Creek. Monitoring using a survey-grade Global Positioning System (GPS) instrument detected movement of the southern part of the Meadow Creek landslide between October 2005 and October 2008, including movement of two of the historical slides-landslides 1 and 2. The most movement during the measurement period occurred within the limits of persistently moving landslide 1 and ranged from about 24 to 64 inches (61-163 cm). Movement of the abutting southern part of the Meadow Creek landslide ranged from approximately 6 to 10 inches (15-25 cm). State Route 9 crosses over approximately a mile (1.6 km) of the southern part of the Meadow Creek landslide, including landslide 1. The highway and its predecessor (State Route 15) have been periodically displaced and damaged by persistent movement of landslide 1. Most of the landslide characteristics, particularly its size, probable depth, and the inferred weak strength and low permeability of clay-rich gouge derived from the Dakota and Cedar Mountain Formations, are adverse to and pose significant challenges to landslide stabilization. Secondary hazards include piping-induced sinkholes along scarps and ground cracks, and debris flows and rock falls from the main-scarp escarpment.

  7. Lake Roosevelt Fisheries Evaluation Program; Meadow Creek vs. Lake Whatcom Stock Kokanee Salmon Investigations in Lake Roosevelt, 2001 Annual Report.

    SciTech Connect

    McLellan, Holly; Scholz, Allan

    2002-03-01

    Lake Roosevelt has been stocked with Lake Whatcom stock kokanee since 1989 with the primary objective of creating a self-sustaining recreational fishery. Due to low return numbers, it was hypothesized a stock of kokanee, native to the upper Columbia River, might perform better than the coastal Lake Whatcom strain. Kokanee from Meadow Creek, a tributary of Kootenay Lake, British Columbia were selected as an alternative stock. Matched pair releases of Lake Whatcom and Meadow Creek kokanee were made from Sherman Creek Hatchery in late June 2000 and repeated in 2001. Stock performance between Lake Whatcom and Meadow Creek kokanee was evaluated using three performance measures; (1) the number of returns to Sherman Creek, the primary egg collection facility, (2) the number of returns to other tributaries and (3) the number of returns to the creel. Kokanee were collected during five passes through the reservoir via electrofishing, which included 87 tributary mouths during the fall of 2000 and 2001. Chi-square analysis indicated age two Meadow Creek kokanee returned to Sherman Creek in significantly higher numbers when compared to the Whatcom stock in 2000 ({chi}{sup 2} = 736.6; d.f. = 1; P < 0.01) and 2001 ({chi}{sup 2} = 156.2; d.f. = 1; P < 0.01). Reservoir wide recoveries of age two kokanee had similar results in 2000 ({chi}{sup 2} = 735.3; d.f. = 1; P < 0.01) and 2001 ({chi}{sup 2} = 150.1; d.f. = 1; P < 0.01). Six Lake Whatcom and seven Meadow Creek three year olds were collected in 2001. The sample size of three year olds was too small for statistical analysis. No kokanee were collected during creel surveys in 2000, and two (age three kokanee) were collected in 2001. Neither of the hatchery kokanee collected were coded wire tagged, therefore stock could not be distinguished. After two years of monitoring, neither Meadow Creek or Lake Whatcom kokanee appear to be capable of providing a run of three-year-old spawners to sustain stocking efforts. The small number of

  8. Lake Roosevelt Fisheries Evaluation Program; Meadow Creek vs. Lake Whatcom Stock Kokanee Salmon Investigations in Lake Roosevelt, Annual Report 2002.

    SciTech Connect

    McLellan, Holly

    2003-03-01

    Lake Whatcom, Washington kokanee have been stocked in Lake Roosevelt since 1987 with the primary objective of creating a self-sustaining fishery. Success has been limited by low recruitment to the fishery, low adult returns to hatcheries, and a skewed sex ratio. It was hypothesized that a stock native to the upper Columbia River might perform better than the coastal Lake Whatcom stock. Kokanee from Meadow Creek, a tributary of Kootenay Lake, British Columbia were selected as an alternative stock. Post smolts from each stock were released from Sherman Creek Hatchery in late June 2000 and repeated in 2001. Stock performance was evaluated using three measures; (1) number of returns to Sherman Creek, the primary egg collection facility, (2) the number of returns to 86 tributaries sampled and, (3) the number of returns to the creel. In two repeated experiments, neither Meadow Creek or Lake Whatcom kokanee appeared to be capable of providing a run of three-year old spawners to sustain stocking efforts. Less than 10 three-years olds from either stock were collected during the study period. Chi-square analysis indicated age two Meadow Creek kokanee returned to Sherman Creek and to other tributaries in significantly higher numbers when compared to the Lake Whatcom stock in both 2000 and 2001. However, preliminary data from the Spokane Tribe of Indians indicated that a large number of both stocks were precocial before they were stocked. The small number of hatchery three-year olds collected indicated that the current hatchery rearing and stocking methods will continue to produce a limited jacking run largely composed of precocious males and a small number of three-year olds. No kokanee from the study were collected during standard lake wide creel surveys. Supplemental creel data, including fishing derbies, test fisheries, and angler diaries, indicated anglers harvested two-year-old hatchery kokanee a month after release. The majority of the two-year old kokanee harvested

  9. Meadow birds as indicators.

    PubMed

    Beintema, A J

    1983-09-01

    The use of birds as indicators for 'biological qualities' is not without risks, and should always be based on a sound knowledge of population dynamics and ecological requirements of the species involved. Meadow birds form a comparatively well-studied group of waders, which breed in Dutch grasslands, heavily influenced by agricultural management. The individual species show different tolerances to intensity levels of management, and can therefore be used as indicators for these levels. PMID:24259105

  10. Baseline water quality of Long Meadow Lake, Ponds AP-9 and AP-10, and Black Dog Creek, Hennepin and Dakota counties, Minnesota

    USGS Publications Warehouse

    Payne, G.A.

    1977-01-01

    Long Meadow Lake, Black Dog Creek, and Ponds AP-9 and AP-10 which lie in an area designated for a trunk highway bridge crossing the Minnesota River, were sampled for baseline water quality prior to construction of the bridge. Data collected show that dissolved solids fluctuate seasonally. Dissolved oxygen:/ranged from less than 1 milligram per liter under an ice cover to 13-9 milligrams per liter in the September sample at site 4 in Long Meadow Lake. The phytoplankton analyses showed pulses in algae populations, blue-green algae being the dominant type in at least one sample from each of the water courses.

  11. Micrometeorological measurements at Ash Meadows and Corn Creek Springs, Nye and Clark counties, Nevada, 1986-87

    USGS Publications Warehouse

    Johnson, M.J.; Pupacko, Alex

    1992-01-01

    Micrometeorological data were collected at Ash Meadows and Corn Creek Springs, Nye and Clark Counties, Nevada, from October 1, 1986 through September 30, 1987. The data include accumulated measurements recorded hourly or every 30 minutes, at each site, for the following climatic variables: air temperature, wind speed, relative humidity, precipitation, solar radiation, net radiation, and soil-heat flux. Periodic sampling of sensible-heat flux and latent-heat flux were also recorded using 5-minute intervals of accumulated data. Evapotranspiration was calculated by both the eddy-correlation method and the Penman combination method. The data collected and the computer programs used to process the data are available separately on three magnetic diskettes in card-image format. (USGS)

  12. Lake Roosevelt Fisheries Evaluation Program : Meadow Creek vs. Lake Whatcom Stock Kokanee Salmon Investigations in Lake Roosevelt Annual Report 2000-2001.

    SciTech Connect

    McLellan, Holly J.; Scholz, Allan T.

    2001-07-01

    Lake Roosevelt has been stocked with Whatcom stock kokanee since 1989 to mitigate for anadromous salmon losses caused by the construction of Grand Coulee Dam. The primary objective of the hatchery plantings was to create a self-sustaining recreational fishery. Due to low return numbers, it was hypothesized a native stock of kokanee might perform better than the coastal Whatcom strain. Therefore, kokanee from Meadow Creek, a tributary of Kootenay Lake, British Columbia were selected as an alternative stock. Matched pair releases of Whatcom stock and Meadow Creek kokanee were made from Sherman Creek in late June 2000. Stock performance between Lake Whatcom and Meadow Creek kokanee was evaluated through three performance measures (1) returns to Sherman Creek, the primary egg collection facility, (2) returns to other tributaries, indicating availability for angler harvest, and (3) returns to the creel. A secondary objective was to evaluate the numbers collected at downstream fish passage facilities. Age 2 kokanee were collected during five passes through the reservoir, which included 89 tributaries between August 17th and November 7th, 2000. Sherman Creek was sampled once a week because it was the primary egg collection location. A total of 2,789 age 2 kokanee were collected, in which 2,658 (95%) were collected at Sherman Creek. Chi-square analysis indicated the Meadow Creek kokanee returned to Sherman Creek in significantly higher numbers compared to the Whatcom stock ({chi}{sup 2} = 734.4; P < 0.01). Reservoir wide recoveries indicated similar results ({chi}{sup 2} = 733.1; P < 0.01). No age 2 kokanee were collected during creel surveys. Age 3 kokanee are expected to recruit to the creel in 2001. No age 2 kokanee were collected at the fish passage facilities due to a 170 mm size restriction at the fish passage centers. Age 3 kokanee are expected to be collected at the fish passage centers during 2001. Stock performance cannot be properly evaluated until 2001, when

  13. The Hydrodynamics of Natural and Incised Mountain Meadows

    NASA Astrophysics Data System (ADS)

    Essaid, H.; Hill, B. R.

    2012-12-01

    Surface water and groundwater flow and storage in mountain meadows are important hydrologic components of watershed systems. Historical grazing and land development have caused channel incision and streambed lowering in a large fraction of Sierra Nevada meadows. This in turn, has resulted in lowering of groundwater tables and changes in the magnitude and timing of fluxes and storage changes in the meadows and watersheds. The hydrodynamics of mountain meadows under natural and incised conditions has been investigated using the U.S. Geological Survey (USGS) coupled surface water - groundwater flow model GSFLOW. Processes represented in this model include: daily rain, snowfall and snowmelt; streamflow, surface runoff, interflow and infiltration; near-surface soil-zone storage and evapotranspiration; and subsurface unsaturated zone and groundwater flow and evapotranspiration. The Sagehen Creek watershed, located on the east slope of the northern Sierra Nevada near Truckee, California, USA, was used as the basis for watershed topography, hydrography and soil properties. Depth-dependent bedrock hydraulic properties and meadow stratigraphy were varied in model simulations. The results from this coupled modeling approach illustrate the interdependence between bedrock and meadow hydrology, and between surface and groundwater flow through the meadow. Wet meadow conditions formed when the bedrock was sufficiently permeable and transmitted flows to the meadows at a rate that maintained high water tables. Meadows with lower permeability sediments sustained longer wet seasons and did not dry out as quickly. The net effect of stream incision on flow from the meadow to the stream was complex. Stream incision resulted in decreased overland flow and interflow, and increased groundwater discharge from the meadow to the stream. During the wet spring season when groundwater storage was being replenished (especially during wet years) surface runoff and interflow decreased with incision

  14. Meadow Fescue: The Forgotten Grass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the early 1900s, before tall fescue was introduced to the USA, meadow fescue was a major pasture crop east of the Mississippi River, with millions of acres of seed production in the mid-south. Most of those acres are long gone with the spread of its high-yielding cousin, tall fescue. We have d...

  15. Registration of Arsenal meadow bromegrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The United States Department of Agriculture (ARS) announces the release of the cultivar 'Arsenal' meadow bromegrass [Bromus biebersteinii Roem. & Schult. (excluded)] for use on semiarid rangelands and non-irrigated pastures as a rapid establishing forage grass with early spring growth, good fall nut...

  16. Meadow Fescue in the Driftless Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have identified meadow fescue on over 250 farms in the driftless region of SW Wisconsin, NW Illinois, NE Iowa, and SE Minnesota. Most plants are similar in appearance and their habitats range from wet bottomlands to dry hilltops, dense monocultures to highly degraded pastures with few meadow fes...

  17. Seagrass meadows in a globally changing environment.

    PubMed

    Unsworth, Richard K F; van Keulen, Mike; Coles, Rob G

    2014-06-30

    Seagrass meadows are valuable ecosystem service providers that are now being lost globally at an unprecedented rate, with water quality and other localised stressors putting their future viability in doubt. It is therefore critical that we learn more about the interactions between seagrass meadows and future environmental change in the anthropocene. This needs to be with particular reference to the consequences of poor water quality on ecosystem resilience and the effects of change on trophic interactions within the food web. Understanding and predicting the response of seagrass meadows to future environmental change requires an understanding of the natural long-term drivers of change and how these are currently influenced by anthropogenic stress. Conservation management of coastal and marine ecosystems now and in the future requires increased knowledge of how seagrass meadows respond to environmental change, and how they can be managed to be resilient to these changes. Finding solutions to such issues also requires recognising people as part of the social-ecological system. This special issue aims to further enhance this knowledge by bringing together global expertise across this field. The special issues considers issues such as ecosystem service delivery of seagrass meadows, the drivers of long-term seagrass change and the socio-economic consequences of environmental change to seagrass.

  18. Seagrass meadows in a globally changing environment.

    PubMed

    Unsworth, Richard K F; van Keulen, Mike; Coles, Rob G

    2014-06-30

    Seagrass meadows are valuable ecosystem service providers that are now being lost globally at an unprecedented rate, with water quality and other localised stressors putting their future viability in doubt. It is therefore critical that we learn more about the interactions between seagrass meadows and future environmental change in the anthropocene. This needs to be with particular reference to the consequences of poor water quality on ecosystem resilience and the effects of change on trophic interactions within the food web. Understanding and predicting the response of seagrass meadows to future environmental change requires an understanding of the natural long-term drivers of change and how these are currently influenced by anthropogenic stress. Conservation management of coastal and marine ecosystems now and in the future requires increased knowledge of how seagrass meadows respond to environmental change, and how they can be managed to be resilient to these changes. Finding solutions to such issues also requires recognising people as part of the social-ecological system. This special issue aims to further enhance this knowledge by bringing together global expertise across this field. The special issues considers issues such as ecosystem service delivery of seagrass meadows, the drivers of long-term seagrass change and the socio-economic consequences of environmental change to seagrass. PMID:24874505

  19. Meadow knapweed in the Northeast: Should I know this species?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meadow knapweed (Centaurea x moncktonii) is increasingly prevalent in New York agricultural lands, including pastures, meadows and waste areas. It is a hybrid of black (C. nigra) and brown (C. jacea) knapweeds that can be similar in appearance to the parental species, and we believe that meadow kna...

  20. Registration of 'Hidden Valley' meadow fescue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Hidden Valley' (Reg. No. CV-xxxx, PI xxxxxx) meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.; syn. Festuca pratensis Huds.; syn. Lolium pratense (Huds.) Darbysh.] is a synthetic population originating from 561 parental genotypes. The original germplasm is of unknown central or northern Europ...

  1. Truckee Meadows Community College Assessment Report.

    ERIC Educational Resources Information Center

    Truckee Meadows Community Coll., Sparks, NV.

    This is a self-assessment for Truckee Meadows Community College (TMCC), Nevada. Assessment efforts at the College are intended to engage faculty and administration in a continuous process of examining the quality of programs and services. The assessment addresses the following issues: (1) student learning improvement; (2) demonstrating academic…

  2. Measuring Groundwater Storage Potential in Mountain Meadows using Geophysical Methods at Red Clover Meadow Complex, Sierra Nevada, CA

    NASA Astrophysics Data System (ADS)

    Covey, J.; Cornwell, K.

    2014-12-01

    ABSTRACT The Dotta Canyon meadow, located in the Red Clover Meadow complex, upper Feather River Watershed, Plumas County, California, was studied to measure sediment volume and groundwater storage capacity in this mountain meadow environment. Groundwater resources in mountain meadows play an important role in providing baseflow to local stream systems during dry summer months. Degraded meadows reduce baseflow contributions to local streams throughout the year impacting the local flora and fauna and water resources downstream. Groundwater storage potential of meadows is a function of the total volume of meadow sediments, the types of sediment present and the effective porosity of those materials. Assessing these properties in meadows is difficult though as meadow environments are commonly sensitive to investigative disturbances like drill rigs and backhoes. We applied seismic refraction techniques to measure the thickness of meadow sediments in the 8.3 km2 Dotta Canyon. Specifically we conducted 42 seismic surveys, utilizing forward and reverse profiles to create a depth to bedrock isopach map of the Dotta Canyon meadow. Using ArcGIS software, aerial photographs and field GPS data to measure and calculate the meadow area and limited hand augering, we were able to calculate the volume of sediment in the meadow to be about 2.5E7 cubic meters. Hand augering in the meadow produced a record of meadow stratigraphy and helped determine appropriate locations for the collection of representative core samples. Representative cores were processed for effective porosity using the water porosimetry method. A mean effective porosity of 38%.was applied to volumetric calculations with results suggesting a groundwater storage capacity of 9.4E6 cubic meters.

  3. Genetic diversity and structure in two protected Posidonia oceanica meadows.

    PubMed

    Micheli, Carla; D'Esposito, Daniela; Belmonte, Alessandro; Peirano, Andrea; Valiante, Luigi Maria; Procaccini, Gabriele

    2015-08-01

    Posidonia oceanica meadows growing along the west Mediterranean coastline are under continuous anthropogenic pressure. The way meadow health correlates with genetic and genotypic diversity in P. oceanica, is still under debate. Here we report a microsatellite analysis of two P. oceanica meadows living in protected areas of the Ligurian (Monterosso al Mare, MPA of "Cinque Terre") and central Tyrrhenian Sea (Santa Marinella, regional Site of Community Importance). Both meadows were recently classified as "disturbed", according to shoot density and other phenological parameters. Between the two meadows, Santa Marinella showed higher genetic diversity, while clear genetic substructure was present in both sites, reflecting high spatial heterogeneity. The present study suggests that genetic diversity does not match unequivocally with shoot density and leaf morphology and that small scale intra-meadow heterogeneity is an important factor to consider for establishing the relation between genetic/genotypic variability and health of natural seagrass meadows. PMID:26164681

  4. Hydrologic Data Summary for the Northeast Creek/Fresh Meadow Estuary, Acadia National Park, Maine, 2000-2001

    USGS Publications Warehouse

    Caldwell, James M.; Culbertson, Charles W.

    2007-01-01

    The U.S. Geological Survey, in cooperation with the National Park Service, collected data in Northeast Creek estuary, Mt. Desert Island, Maine, to establish baseline water-quality conditions including estuarine nutrient concentrations. Five sampling sites in Northeast Creek were established and monitored continuously for temperature and specific conductance during May to November, 2000 and 2001. Stream stage, which was affected by ocean tidal dynamics, was recorded at the most downstream site and at one upstream site. Discrete water samples for nutrient concentrations were collected biweekly during May to November, 2000 and 2001, at the five sampling sites, and an additional site seaward of the estuary mouth. Results indicated that the salinity regime of Northeast Creek estuary is dynamic and highly regulated by strong seasonal variations in freshwater runoff, as well as limited seawater exchange caused by a constriction at the bridge, at the downstream end of the estuary. Oligohaline conditions (0.5-5 practical salinity units) occasionally extend to the estuary mouth. During other periods oligohaline and mesohaline (5-20 practical salinity units) conditions exist in some areas of the estuary; polyhaline/marine (20-35 practical salinity units) conditions occasionally exist near the mouth. A saltwater wedge in the bottom water, due to density stratification, was observed to migrate upstream as fresh surface-water inputs diminished during the onset of summer low-flow conditions. Although specific conductance ranged widely at most sites because of tidal influences, other water-quality constituents, including nutrient and chlorophyll-a concentrations, exhibited seasonal distribution patterns in which maximum levels generally occurred in early to mid-summer and again in the fall over both field seasons.

  5. L'Anse Aux Meadows, Newfoundland

    NASA Technical Reports Server (NTRS)

    2008-01-01

    L'Anse aux Meadows is a site on the northernmost tip of the island of Newfoundland, located in the Province of Newfoundland and Labrador, Canada, where the remains of a Viking village were discovered in 1960 by the Norwegians Helge and Anne Ingstad. The only authenticated Viking settlement in North America outside Greenland, it was the site of a multi-year archaeological dig that found dwellings, tools and implements that verified its time frame. The settlement, dating more than five hundred years before Christopher Columbus, contains the earliest European structures in North America. Named a World Heritage site by UNESCO, it is thought by many to be the semi-legendary 'Vinland' settlement of explorer Leif Ericson around AD 1000. The settlement at L'Anse aux Meadows consisted of at least eight buildings, including a forge and smelter, and a lumber yard that supported a shipyard. The largest house measured 28.8 by 15.6 m and consisted of several rooms. Sewing and knitting tools found at the site indicate women were present at L'Anse aux Meadows

    The image was acquired on September 14, 2007, covers an area of 14.2 x 14.6 km, and is located at 51.5 degrees north latitude, 55.6 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  6. Quantifying Volume of Groundwater in High Elevation Meadows

    NASA Astrophysics Data System (ADS)

    Ciruzzi, D.; Lowry, C.

    2013-12-01

    Assessing the current and future water needs of high elevation meadows is dependent on quantifying the volume of groundwater stored within the meadow sediment. As groundwater dependent ecosystems, these meadows rely on their ability to capture and store water in order to support ecologic function and base flow to streams. Previous research of these meadows simplified storage by assuming a homogenous reservoir of constant thickness. These previous storage models were able to close the water mass balance, but it is unclear if these assumptions will be successful under future anthropogenic impacts, such as increased air temperature resulting in dryer and longer growing seasons. Applying a geophysical approach, ground-penetrating radar was used at Tuolumne Meadows, CA to qualitatively and quantitatively identify the controls on volume of groundwater storage. From the geophysical results, a three-dimensional model of Tuolumne Meadows was created, which identified meadow thickness and bedrock geometry. This physical model was used in a suite of numerical models simulating high elevation meadows in order to quantify volume of groundwater stored with temporal and spatial variability. Modeling efforts tested both wet and dry water years in order to quantify the variability in the volume of groundwater storage for a range of aquifer properties. Each model was evaluated based on the seasonal depth to water in order to evaluate a particular scenario's ability to support ecological function and base flow. Depending on the simulated meadows ability or inability to support its ecosystem, each representative meadow was categorized as successful or unsuccessful. Restoration techniques to increase active storage volume were suggested at unsuccessful meadows.

  7. Meadow contraction and extinction debt in meadow plants and moths in the Western Cascades

    EPA Science Inventory

    Meadows in the western Cascades have contracted and fragmented by approximately 50% in the past 60 years. These habitats occupy only about 5% of the landscape of the western Cascades but are important for the preservation of biodiversity and rare species. This habitat loss and ...

  8. Meadow Fescue in the Driftless Region, Part Two

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have identified meadow fescue on over 250 farms in the driftless region of SW Wisconsin, NW Illinois, NE Iowa, and SE Minnesota. Most plants are similar in appearance and their habitats range from wet bottomlands to dry hilltops, dense monocultures to highly degraded pastures with few meadow fes...

  9. GEOMORPHIC CONTROLS ON MEADOW ECOSYSTEMS IN THE CENTRAL GREAT BASIN

    EPA Science Inventory

    Wet meadows, riparian corridor phreatophyte assemblages, and high-altitude spring-fed aspen meadows comprise a very small percentage of the total landscape of the mountain ranges in the central Great Basin however, they represent important ecological environments. We have used s...

  10. Response of mountain meadows to grazing by recreational pack stock

    USGS Publications Warehouse

    Cole, David N.; Van Wagtendonk, Jan W.; McClaran, Mitchel P.; Moore, Peggy E.; McDougald, Neil K.

    2004-01-01

    Effects of recreational pack stock grazing on mountain meadows in Yosemite National Park were assessed in a 5-year study. Yosemite is a designated wilderness, to be managed such that its natural conditions are preserved. Studies were conducted in 3 characteristic meadow types: shorthair sedge (Carex filifolia Nutt.), Brewer's reed grass (Calamagrostis breweri Thurber), and tufted hairgrass [Deschampsia cespitosa (L.) Beauv.]. Horses and mules grazed experimental plots at intensities of 15 to 69% utilization for 4 seasons. In all 3 meadows, grazing caused decreases in productivity. The mean reduction after 4 years of grazing was 18% in the shorthair sedge meadow, 17% in the Brewer's reed grass meadow, and 22% in the tufted hairgrass meadow. Grazing also caused shifts in basal groundcover (usually a reduction in vegetation cover and increase in bare soil cover), and changes in species composition. Productivity and vegetation cover decreased as percent utilization increased, while bare soil cover increased as utilization increased. Changes in species composition were less predictably related to differences in grazing intensity. Passive management of grazing is insufficient in wilderness areas that are regularly used by groups with recreational stock. Wilderness managers need to monitor meadow conditions and the grazing intensities that occur. Our study suggests that biomass and ground cover are more sensitive indicators of grazing impact than species composition. Managers must make decisions about maximum acceptable levels of grazing impact and then develop guidelines for maximum use levels, based on data such as ours that relates grazing intensity to meadow response.

  11. Montane Meadow Plant Community Response to Livestock Grazing

    NASA Astrophysics Data System (ADS)

    Freitas, Matthew R.; Roche, Leslie M.; Weixelman, Dave; Tate, Kenneth W.

    2014-08-01

    We examined long-term (10 years) meadow plant community responses to (1) livestock grazing under riparian grazing utilization limits; (2) suspension of livestock grazing; and (3) meadow site wetness and precipitation on the Inyo National Forest, California. Observed trends in meadow plant species richness, diversity, and frequency of soil stabilizing species were not significantly different between grazed ( N = 16) and non-grazed ( N = 9) study sites ( P > 0.12 in all cases). Modest increases in richness and diversity were observed over the study period, but frequency of soil stabilizing species was constant. These results suggest that riparian conservation grazing strategies implemented during the study period neither degraded nor hampered recovery of meadow plant community conditions relative to non-grazed conditions. Meadow site wetness was negatively correlated to richness ( P < 0.01) and diversity ( P < 0.01), but was positively correlated to soil stabilization ( P = 0.02). Precipitation was not a significant predictor for plant community responses.

  12. Conifer Encroachment into Tuolumne Meadows, Yosemite National Park: How Anthropogenic Impacts to Local Hydrology Affect Meadow Habitat

    NASA Astrophysics Data System (ADS)

    Roche, J. W.; Lundquist, J. L.; Cooper, D. J.; King, J. C.; Flint, L. E.; Flint, A. L.

    2006-12-01

    Tuolumne Meadows, at 2600 m in Yosemite National Park, is one of the most popular sub-alpine destinations in the Sierra Nevada of California and, as such, one of the most impacted by current and historic use. Conifer (lodgepole pine) encroachment into the meadow has been managed for over 70 years to maintain vistas and to protect potentially impacted meadow vegetation. This study seeks to characterize hydrologic, soil, and vegetation assemblages throughout the affected area, document departures from expected relationships, and identify causative disruptive mechanisms. The snowmelt-dominated Tuolumne River, an integral part of the meadow system, drains 200 km{2} of the Sierra Nevada crest above the meadows. Much of the meadow area consists of recently glaciated granitic bedrock overlain by 1-2 meters of alluvial sand and gravel topped with 30-40 cm of organic-rich meadow soil. Almost all areas examined to date reveal plant assemblages and hydrologic regimes that are inconsistent with the formation of these meadow soils. In upland sites, this is characterized by groundwater conditions that are incapable of supporting meadow forming vegetation and soils. In lower areas, where groundwater levels remain close to the surface throughout the summer, the vegetation present lacks plant species with high below ground biomass production, and could not have formed the existing meadow soils. Potential mechanisms for these disruptions include ditching associated with road construction and drainage, changes in river morphology due to loss of willow riparian vegetation, and lingering impacts of intensive grazing more than a century ago. Patterns of conifer invasion as well as tree-ring and fire scar chronologies were also documented and appear to reflect similar responses to the impacts mentioned above. Results of this study are intended to inform future management and possible restoration of the area.

  13. Photosynthetic activity buffers ocean acidification in seagrass meadows

    NASA Astrophysics Data System (ADS)

    Hendriks, I. E.; Olsen, Y. S.; Ramajo, L.; Basso, L.; Steckbauer, A.; Moore, T. S.; Howard, J.; Duarte, C. M.

    2014-01-01

    Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5-12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pHNBS and max and range ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min ΩAr, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range ΩAr within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, ΩAr and carbonate deposition. Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit from the modification of the carbonate system by the meadow. There is, however, concern for the ability of seagrasses to provide modifications of similar importance in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, on which LAI is based. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows.

  14. Modeling the gopher-meadow eco-geomorphic system on montane hillslopes

    NASA Astrophysics Data System (ADS)

    Winchell, E. W.; Doak, D. F.; Anderson, R. S.

    2013-12-01

    On montane hillslopes of Colorado's Front Range, the transport of soil by gophers can dominate the modern geomorphic system in meadows. Qualitative observations reveal that gophers prefer to forage in meadows over forests, that seedling roots are consumed by gophers, and that trees commonly occupy the rocky crests of hills overlooking open meadow hillslopes. This motivates a numerical model of gopher-mediated transport of soil and the long-term evolution of the coupled ecological-geomorphic system through quantitative observations from a manipulative experiment on meadow-centered plots in the Boulder Creek CZO in the Colorado Front Range montane forest. The ecological and geomorphic processes in the coupled system we wish to model must include: seedling establishment and damage, gopher tunneling geometries and resulting mound generation, mound material transport driven by rain and hail and by ungulate trampling, vegetative lock-down of mound material, and resulting changes in the soil depth and rockiness of the landscape. We must therefore have algorithms to capture the feedback mechanisms between gopher activity and the growth and potential death of trees, the casting of seeds and their likelihood of germination, and the spatial distribution of plants. The ecological component interacts with the soils/critical zone layer through feedbacks that include the dependence of gopher activity on root density, depth, and size, undergrowth availability, and the dependence of the rate of change of soil thickness on gradients in gopher-mediated transport. Results of a preliminary cellular automaton model which captures the essence of these geomorphic-ecological feedbacks can readily address the role of gophers in limiting the encroachment of trees into meadow patches. The bioturbation of the meadows, and the downslope transport of soil within them, is much more efficient than that in the forest, which sees little to no gopher activity. These geomorphic transport hotspots will

  15. Experimental infection of meadow voles (Microtus pennsylvanicus) with sheep scrapie

    USGS Publications Warehouse

    Carlson, CM; Schneider, Jay R.; Pedersen, Janice C.; Heisey, Dennis M.; Johnson, Christopher J.

    2015-01-01

    Meadow voles (Microtus pennsylvanicus) are permissive to chronic wasting disease (CWD) infection, but their susceptibility to other transmissible spongiform encephalopathies (TSEs) is poorly characterized. In this initial study, we intracerebrally challenged 6 meadow voles with 2 isolates of sheep scrapie. Three meadow voles acquired a TSE after the scrapie challenge and an extended incubation period. The glycoform profile of proteinase K-resistant prion protein (PrP(res)) in scrapie-sick voles remained similar to the sheep inocula, but differed from that of voles clinically affected by CWD. Vacuolization patterns and disease-associated prion protein (PrP(Sc)) deposition were generally similar in all scrapie-affected voles, except in the hippocampus, where PrP(Sc) staining varied markedly among the animals. Our results demonstrate that meadow voles can acquire a TSE after intracerebral scrapie challenge and that this species could therefore prove useful for characterizing scrapie isolates.

  16. Experimental infection of meadow voles (Microtus pennsylvanicus) with sheep scrapie.

    PubMed

    Carlson, Christina M; Schneider, Jay R; Pedersen, Joel A; Heisey, Dennis M; Johnson, Christopher J

    2015-01-01

    Meadow voles (Microtus pennsylvanicus) are permissive to chronic wasting disease (CWD) infection, but their susceptibility to other transmissible spongiform encephalopathies (TSEs) is poorly characterized. In this initial study, we intracerebrally challenged 6 meadow voles with 2 isolates of sheep scrapie. Three meadow voles acquired a TSE after the scrapie challenge and an extended incubation period. The glycoform profile of proteinase K-resistant prion protein (PrP(res)) in scrapie-sick voles remained similar to the sheep inocula, but differed from that of voles clinically affected by CWD. Vacuolization patterns and disease-associated prion protein (PrP(Sc)) deposition were generally similar in all scrapie-affected voles, except in the hippocampus, where PrP(Sc) staining varied markedly among the animals. Our results demonstrate that meadow voles can acquire a TSE after intracerebral scrapie challenge and that this species could therefore prove useful for characterizing scrapie isolates.

  17. Experimental infection of meadow voles (Microtus pennsylvanicus) with sheep scrapie

    PubMed Central

    Carlson, Christina M.; Schneider, Jay R.; Pedersen, Joel A.; Heisey, Dennis M.; Johnson, Christopher J.

    2015-01-01

    Meadow voles (Microtus pennsylvanicus) are permissive to chronic wasting disease (CWD) infection, but their susceptibility to other transmissible spongiform encephalopathies (TSEs) is poorly characterized. In this initial study, we intracerebrally challenged 6 meadow voles with 2 isolates of sheep scrapie. Three meadow voles acquired a TSE after the scrapie challenge and an extended incubation period. The glycoform profile of proteinase K-resistant prion protein (PrPres) in scrapie-sick voles remained similar to the sheep inocula, but differed from that of voles clinically affected by CWD. Vacuolization patterns and disease-associated prion protein (PrPSc) deposition were generally similar in all scrapie-affected voles, except in the hippocampus, where PrPSc staining varied markedly among the animals. Our results demonstrate that meadow voles can acquire a TSE after intracerebral scrapie challenge and that this species could therefore prove useful for characterizing scrapie isolates. PMID:25673912

  18. Key biogeochemical factors affecting soil carbon storage in Posidonia meadows

    NASA Astrophysics Data System (ADS)

    Serrano, Oscar; Ricart, Aurora M.; Lavery, Paul S.; Mateo, Miguel Angel; Arias-Ortiz, Ariane; Masque, Pere; Rozaimi, Mohammad; Steven, Andy; Duarte, Carlos M.

    2016-08-01

    Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2-4 m depth) accumulated 3- to 4-fold higher Corg stocks (averaging 6.3 kg Corg m-2) at 3- to 4-fold higher rates (12.8 g Corg m-2 yr-1) compared to meadows closer to the deep limits of distribution (at 6-8 m depth; 1.8 kg Corg m-2 and 3.6 g Corg m-2 yr-1). In shallower meadows, Corg stocks were mostly derived from seagrass detritus (88 % in average) compared to meadows closer to the deep limit of distribution (45 % on average). In addition, soil accumulation rates and fine-grained sediment content (< 0.125 mm) in shallower meadows (2.0 mm yr-1 and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2 mm yr-1 and 5 %, respectively). The Corg stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg Corg m-2 and 1.2 g Corg m-2 yr-1) were 3- to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8- and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypothesis that Corg storage in seagrass soils is influenced by interactions of biological (e.g., meadow productivity, cover and density), chemical (e.g., recalcitrance of Corg stocks) and physical (e.g., hydrodynamic energy and soil accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats.

  19. Key biogeochemical factors affecting soil carbon storage in Posidonia meadows

    NASA Astrophysics Data System (ADS)

    Serrano, O.; Ricart, A. M.; Lavery, P. S.; Mateo, M. A.; Arias-Ortiz, A.; Masque, P.; Steven, A.; Duarte, C. M.

    2015-11-01

    Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2-4 m depth) accumulated 3 to 4-fold higher Corg stocks (averaging 6.3 kg Corg m-2) at 3 to 4-fold higher rates (12.8 g Corg m-2 yr-1) compared to meadows closer to the deep limits of distribution (at 6-8 m depth; 1.8 kg Corg m-2 and 3.6 g Corg m-2 yr-1). In shallower meadows, Corg stores were mostly derived from seagrass detritus (88 % in average) compared to meadows closer to the deep limit of distribution (45 % on average). Also, sediment accumulation rates and fine-grained sediment content (< 0.125 mm) in shallower meadows (2.0 mm yr-1 and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2 mm yr-1 and 5 %, respectively). The Corg stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg Corg m-2 and 1.2 g Corg m-2 yr-1) were 3 to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8 and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypotheses that Corg storage in seagrass soils is influenced by interactions of biological (e.g. meadow productivity, cover and density), chemical (e.g. recalcitrance of Corg stocks) and physical (e.g. hydrodynamic energy and sediment accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats.

  20. Geochemistry of Mine Waste and Mill Tailings, Meadow Deposits, Streambed Sediment, and General Hydrology and Water Quality for the Frohner Meadows Area, Upper Lump Gulch, Jefferson County, Montana

    USGS Publications Warehouse

    Klein, Terry L.; Cannon, Michael R.; Fey, David L.

    2004-01-01

    Frohner Meadows, an area of low-topographic gradient subalpine ponds and wetlands in glaciated terrane near the headwaters of Lump Gulch (a tributary of Prickly Pear Creek), is located about 15 miles west of the town of Clancy, Montana, in the Helena National Forest. Mining and ore treatment of lead-zinc-silver veins in granitic rocks of the Boulder batholith over the last 120 years from two sites (Frohner mine and the Nellie Grant mine) has resulted in accumulations of mine waste and mill tailings that have been distributed downslope and downstream by anthropogenic and natural processes. This report presents the results of an investigation of the geochemistry of the wetlands, streams, and unconsolidated-sediment deposits and the hydrology, hydrogeology, and water quality of the area affected by these sources of ore-related metals. Ground water sampled from most shallow wells in the meadow system contained high concentrations of arsenic, exceeding the Montana numeric water-quality standard for human health. Transport of cadmium and zinc in ground water is indicated at one site near Nellie Grant Creek based on water-quality data from one well near the creek. Mill tailings deposited in upper Frohner Meadow contribute large arsenic loads to Frohner Meadows Creek; Nellie Grant Creek contributes large arsenic, cadmium, and zinc loads to upper Frohner Meadows. Concentrations of total-recoverable cadmium, copper, lead, and zinc in most surface-water sites downstream from the Nellie Grant mine area exceeded Montana aquatic-life standards. Nearly all samples of surface water and ground water had neutral to slightly alkaline pH values. Concentrations of arsenic, cadmium, lead, and zinc in streambed sediment in the entire meadow below the mine waste and mill tailings accumulations are highly enriched relative to regional watershed-background concentrations and exceed consensus-based, probable-effects concentrations for streambed sediment at most sites. Cadmium, copper, and

  1. A subsurface model of the beaver meadow complex

    NASA Astrophysics Data System (ADS)

    Nash, C.; Grant, G.; Flinchum, B. A.; Lancaster, J.; Holbrook, W. S.; Davis, L. G.; Lewis, S.

    2015-12-01

    Wet meadows are a vital component of arid and semi-arid environments. These valley spanning, seasonally inundated wetlands provide critical habitat and refugia for wildlife, and may potentially mediate catchment-scale hydrology in otherwise "water challenged" landscapes. In the last 150 years, these meadows have begun incising rapidly, causing the wetlands to drain and much of the ecological benefit to be lost. The mechanisms driving this incision are poorly understood, with proposed means ranging from cattle grazing to climate change, to the removal of beaver. There is considerable interest in identifying cost-effective strategies to restore the hydrologic and ecological conditions of these meadows at a meaningful scale, but effective process based restoration first requires a thorough understanding of the constructional history of these ubiquitous features. There is emerging evidence to suggest that the North American beaver may have had a considerable role in shaping this landscape through the building of dams. This "beaver meadow complex hypothesis" posits that as beaver dams filled with fine-grained sediments, they became large wet meadows on which new dams, and new complexes, were formed, thereby aggrading valley bottoms. A pioneering study done in Yellowstone indicated that 32-50% of the alluvial sediment was deposited in ponded environments. The observed aggradation rates were highly heterogeneous, suggesting spatial variability in the depositional process - all consistent with the beaver meadow complex hypothesis (Polvi and Wohl, 2012). To expand on this initial work, we have probed deeper into these meadow complexes using a combination of geophysical techniques, coring methods and numerical modeling to create a 3-dimensional representation of the subsurface environments. This imaging has given us a unique view into the patterns and processes responsible for the landforms, and may shed further light on the role of beaver in shaping these landscapes.

  2. Quantifying the Restorable Water Volume of California's Sierra Nevada Meadows

    NASA Astrophysics Data System (ADS)

    Emmons, J. D.; Yarnell, S. M.; Fryjoff-Hung, A.; Viers, J.

    2013-12-01

    The Sierra Nevada is estimated to provide over 66% of California's water supply, which is largely derived from snowmelt. Global climate warming is expected to result in a decrease in snow pack and an increase in melting rate, making the attenuation of snowmelt by any means, an important ecosystem service for ensuring water availability. Montane meadows are dispersed throughout the mountain range and can act like natural reservoirs, and also provide wildlife habitat, water filtration, and water storage. Despite the important role of meadows in the Sierra Nevada, a large proportion is degraded from stream incision, which increases volume outflows and reduces overbank flooding, thus reducing infiltration and potential water storage. Restoration of meadow stream channels would therefore improve hydrological functioning, including increased water storage. The potential water holding capacity of restored meadows has yet to be quantified, thus this research seeks to address this knowledge gap by estimating the restorable water volume due to stream incision. More than 17,000 meadows were analyzed by categorizing their erosion potential using channel slope and soil texture, ultimately resulting in six general erodibility types. Field measurements of over 100 meadows, stratified by latitude, elevation, and geologic substrate, were then taken and analyzed for each erodibility type to determine average depth of incision. Restorable water volume was then quantified as a function of water holding capacity of the soil, meadow area and incised depth. Total restorable water volume was found to be 120 x 10^6 m3, or approximately 97,000 acre-feet. Using 95% confidence intervals for incised depth, the upper and lower bounds of the total restorable water volume were found to be 107 - 140 x 10^6 m3. Though this estimate of restorable water volume is small in regards to the storage capacity of typical California reservoirs, restoration of Sierra Nevada meadows remains an important

  3. Impact of mooring activities on carbon stocks in seagrass meadows.

    PubMed

    Serrano, O; Ruhon, R; Lavery, P S; Kendrick, G A; Hickey, S; Masqué, P; Arias-Ortiz, A; Steven, A; Duarte, C M

    2016-01-01

    Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (Corg) stocks, which may contribute to increasing atmospheric CO2. This study presents the first estimates of loss of Corg stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were sampled from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The Corg stores have been compromised by the mooring deployment from 1930s onwards, which involved both the erosion of existing sedimentary Corg stores and the lack of further accumulation of Corg. On average, undisturbed meadows had accumulated ~6.4 Kg Corg m(-2) in the upper 50 cm-thick deposits at a rate of 34 g Corg m(-2) yr(-1). The comparison of Corg stores between meadows and mooring scars allows us to estimate a loss of 4.8 kg Corg m(-2) in the 50 cm-thick deposits accumulated over ca. 200 yr as a result of mooring deployments. These results provide key data for the implementation of Corg storage credit offset policies to avoid the conversion of seagrass ecosystems and contribute to their preservation. PMID:26979407

  4. Impact of mooring activities on carbon stocks in seagrass meadows

    NASA Astrophysics Data System (ADS)

    Serrano, O.; Ruhon, R.; Lavery, P. S.; Kendrick, G. A.; Hickey, S.; Masqué, P.; Arias-Ortiz, A.; Steven, A.; Duarte, C. M.

    2016-03-01

    Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (Corg) stocks, which may contribute to increasing atmospheric CO2. This study presents the first estimates of loss of Corg stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were sampled from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The Corg stores have been compromised by the mooring deployment from 1930s onwards, which involved both the erosion of existing sedimentary Corg stores and the lack of further accumulation of Corg. On average, undisturbed meadows had accumulated ~6.4 Kg Corg m‑2 in the upper 50 cm-thick deposits at a rate of 34 g Corg m‑2 yr‑1. The comparison of Corg stores between meadows and mooring scars allows us to estimate a loss of 4.8 kg Corg m‑2 in the 50 cm-thick deposits accumulated over ca. 200 yr as a result of mooring deployments. These results provide key data for the implementation of Corg storage credit offset policies to avoid the conversion of seagrass ecosystems and contribute to their preservation.

  5. Impact of mooring activities on carbon stocks in seagrass meadows

    PubMed Central

    Serrano, O.; Ruhon, R.; Lavery, P. S.; Kendrick, G. A.; Hickey, S.; Masqué, P.; Arias-Ortiz, A.; Steven, A.; Duarte, C. M.

    2016-01-01

    Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (Corg) stocks, which may contribute to increasing atmospheric CO2. This study presents the first estimates of loss of Corg stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were sampled from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The Corg stores have been compromised by the mooring deployment from 1930s onwards, which involved both the erosion of existing sedimentary Corg stores and the lack of further accumulation of Corg. On average, undisturbed meadows had accumulated ~6.4 Kg Corg m−2 in the upper 50 cm-thick deposits at a rate of 34 g Corg m−2 yr−1. The comparison of Corg stores between meadows and mooring scars allows us to estimate a loss of 4.8 kg Corg m−2 in the 50 cm-thick deposits accumulated over ca. 200 yr as a result of mooring deployments. These results provide key data for the implementation of Corg storage credit offset policies to avoid the conversion of seagrass ecosystems and contribute to their preservation. PMID:26979407

  6. A Test of Climate Change Refugia in Montane Meadow Systems

    NASA Astrophysics Data System (ADS)

    Morelli, T.; Maher, S. P.; Moritz, C.; Beissinger, S. R.

    2013-12-01

    Climate change refugia, areas on the landscape buffered from recent shifts in temperature and precipitation patterns, are potentially important to understand population responses to anthropogenic climate change. With funding from the California Landscape Conservation Cooperative and the National Science Foundation, we used occupancy and genetic data to test the climate change refugia concept. Specifically, we estimated connectivity between Sierra Nevada meadows based on features such as topography and hydrology and determined the amount of change that meadows experienced during the 20th century. We then examined fine-scale population genetic structure across the California range of a montane meadow specialist, the Belding's ground squirrel (Urocitellus beldingi). We found distinctive genetic structure across the state as well as within the smaller geographic area of the central Sierra Nevada. Genetic diversity between survey sites predicted climate change refugia and population persistence supported hypothetical landscape connectivity. Our results highlight an important tool in climate change adaptation, given the limited resources available to land managers.

  7. Using digital photography to examine grazing in montane meadows

    USGS Publications Warehouse

    McIlroy, Susan K.; Allen-Diaz, Barbara H.; Berg, Alexander C.

    2011-01-01

    Cattle (Bos taurus) numbers on national forests are allocated based on allotment grazing capacity, but spatial patterns of timing and density at smaller scales are difficult to assess. However, it is often in meadows or riparian areas that grazing may affect hydrology, biodiversity, and other important ecosystem characteristics. To explore real-time animal presence in montane meadows we distributed 18 digital cameras across nine sites in the Sierra National Forest, California. Our objectives were to document seasonal and diurnal presence of both cattle and mule deer (Odocoileus hemionus), identify the effects of three fencing treatments on animal distribution, and test digital photography as a tool for documenting cattle presence. We recorded 409 399 images during daylight hours for two grazing seasons, and we identified 5 084 and 24 482 cattle "marks" (instances of animal occurrence) in 2006 and 2007, respectively. Deer presence was much lower, with 331 marks in 2006 and 598 in 2007. Morning cattle presence was highest before 0800 hours both years (13.7% and 15.4% of total marks for 2006 and 2007, respectively). Marks decreased until 1100 hours and then increased around 1400 hours and remained relatively stable until 1900 hours. Marks then rose precipitously, with >20% of total marks recorded after 1900 hours both years. Deer presence was less than 10% per hour until 1800 hours, when >20% of total marks were recorded after this time both years. Among treatments, cattle marks were highest outside fences at partially fenced meadows, and deer were highest within completely fenced meadows. Our experience suggests that cameras are not viable tools for meadow monitoring due to variation captured within meadows and the time and effort involved in image processing and review.

  8. RELATIONSHIPS OF MEADOW VEGETATION TO GROUNDWATER DEPTH: EFFECTS OF PRECIPITATION VARIABILITY AND STREAM INCISION

    EPA Science Inventory

    The composition of riparian meadow vegetation is controlled by access to groundwater. Depth to groundwater is controlled by meadow architecture and water source, and changes in either meadow architecture or water source through stream incision or changes in annual precipitation c...

  9. Watershed-scale modeling of streamflow change in incised montane meadows

    USGS Publications Warehouse

    Essaid, Hedeff I.; Hill, Barry R.

    2014-01-01

    Land use practices have caused stream channel incision and water table decline in many montane meadows of the Western United States. Incision changes the magnitude and timing of streamflow in water supply source watersheds, a concern to resource managers and downstream water users. The hydrology of montane meadows under natural and incised conditions was investigated using watershed simulation for a range of hydrologic conditions. The results illustrate the interdependence between: watershed and meadow hydrology; bedrock and meadow aquifers; and surface and groundwater flow through the meadow for the modeled scenarios. During the wet season, stream incision resulted in less overland flow and interflow and more meadow recharge causing a net decrease in streamflow and increase in groundwater storage relative to natural meadow conditions. During the dry season, incision resulted in less meadow evapotranspiration and more groundwater discharge to the stream causing a net increase in streamflow and a decrease in groundwater storage relative to natural meadow conditions. In general, for a given meadow setting, the magnitude of change in summer streamflow and long-term change in watershed groundwater storage due to incision will depend on the combined effect of: reduced evapotranspiration in the eroded meadow; induced groundwater recharge; replenishment of dry season groundwater storage depletion in meadow and bedrock aquifers by precipitation during wet years; and groundwater storage depletion that is not replenished by precipitation during wet years.

  10. Groundwater Storage Dynamics in High Elevation Meadows Affected By Complex Aquifer Geometry

    NASA Astrophysics Data System (ADS)

    Ciruzzi, D.; Lowry, C.

    2014-12-01

    The Sierra Nevada represents a cascading hydrologic cycle where snowpack, meadow aquifers, and streams are all hydrologically connected. Monitoring the water balance within high elevation meadows is vital in order to effectively quantify watershed scale storage dynamics, which support meadow ecological communities as well as downstream users. In this case, much of the San Francisco, CA water supply originates from the seasonally released snowmelt from high elevation meadows to downstream reservoirs. In previous studies of high elevation meadows, the water mass balance was closed under the assumption that the meadow sediment was spatially uniform in thickness. Here, complex aquifer geometry was identified in Tuolumne Meadows, CA from a high-resolution ground-penetrating radar survey. This new geometry was compared to the previous geologic model of high elevation meadow aquifers using numerical models simulating both current and future snowmelt scenarios. In addition, the impact of variability in meadow sediment and slope were evaluated to quantify storage properties of representative Sierra Nevada meadow types. Results demonstrate that the previous aquifer geometry model significantly overestimates both the spatial and temporal volumetric storage and release of groundwater to streams. These implications are noteworthy for ecosystem restoration and water supply strategies that aim to rectify water supply to and from these meadows especially when considering drought scenarios. In order to move forward and effectively and efficiently monitor the seasonal volume of water stored within the Sierra Nevada, complex aquifer geometry within high elevation meadows must be considered.

  11. Analytical results for 35 mine-waste tailings cores and six bed-sediment samples, and an estimate of the volume of contaminated material at Buckeye meadow on upper Basin Creek, northern Jefferson County, Montana

    USGS Publications Warehouse

    Fey, D.L.; Church, S.E.; Finney, C.J.

    1999-01-01

    Metal-mining related wastes in the Boulder River basin study area in northern Jefferson County, Montana have been implicated in their detrimental effects on water quality with regard to acidgeneration and toxic-metal solubilization. Flotation-mill tailings in the meadow below the Buckeye mine, hereafter referred to as the Buckeye mill-tailings site, have been identified as significant contributors to water quality degradation of Basin Creek, Montana. Basin Creek is one of three tributaries to the Boulder River in the study area; bed sediments and waters draining from the Buckeye mine have also been implicated. Geochemical analysis of 35 tailings cores and six bed-sediment samples was undertaken to determine the concentrations of Ag, As, Cd, Cu, Pb,and Zn present in these materials. These elements are environmentally significant, in that they can be toxic to fish and/or the invertebrate organisms that constitute their food. A suite of one-inch cores of dispersed flotation-mill tailings and underlying premining material was taken from a large, flat area north of Basin Creek near the site of the Buckeye mine. Thirty-five core samples were taken and divided into 204 subsamples. The samples were analyzed by ICP-AES (inductively coupled plasma-atomic emission spectroscopy) using a mixed-acid digestion. Results of the core analyses show that the elements listed above are present at moderate to very high concentrations (arsenic to 63,000 ppm, silver to 290 ppm, cadmium to 370 ppm, copper to 4,800 ppm, lead to 93,000 ppm, and zinc to 23,000 ppm). Volume calculations indicate that an estimated 8,400 metric tons of contaminated material are present at the site. Six bed-sediment samples were also subjected to the mixed-acid total digestion, and a warm (50oC) 2M HCl-1% H2O2 leach and analyzed by ICP-AES. Results indicate that bed sediments of Basin Creek are only slightly impacted by past mining above the Buckeye-Enterprise complex, moderately impacted at the upper (eastern

  12. Spatial and temporal variations of evapotranspiration signals in Long Meadow, Sequioa National Park, California

    NASA Astrophysics Data System (ADS)

    Conklin, M. H.; Lucas, R. G.

    2010-12-01

    Montane meadows are often locations of groundwater discharge, with their hydrologic fluxes reflecting watershed processes. We analyzed continuously recorded groundwater levels in ten monitoring wells in three transects from the meadow edge to the meadow center for water years 2008-2010 to estimate daily evapotranspiration (ET) rates. Long Meadow, part of the Southern Sierra Critical Zone Observatory, is located at an elevation of 2230 m, is approximately 1.5 km in length and is up to 250 m wide; a 730-ha snow-dominated catchment drains into the meadow. The meadow lies in a glaciated valley over alluvium as thick as 30 m. A stream runs intermittently in both time and space down the meadow from south to north. ET rates from meadow monitoring wells provide 15-minute data that are vital for establishing a water balance for the meadow. Well-derived ET rates vary in space, from the meadow/forest boundary to the meadow stream, and time diurnally, seasonally and inter-annually. Spatially varying but strong ET signals (5-10 mm/d) come from the meadow vegetation, on the meadow slope and/or from the adjacent forested hillslopes of the watershed. ET signals near the meadow stream are muted (2-5 mm/d), but relatively constant over time. Muting is attributed to meadow grasses using surface water for ET. Temporal ET trends depend on timing of snowmelt, phenology of the meadow vegetation, and by the magnitude of winter precipitation in the watershed. Chamber measurements, taken during the same period, match ET signals on the meadow slopes during the peak of the vegetation growing season (June to August). Vegetation in the meadow senesces in the late summer/early fall, however, wells located near the meadow/forest boundary continue to exhibit significant ET signals well into the fall, after senescence. Diurnal fluctuations in water-level monitoring wells installed in the sap-rock complex outside the meadow boundary identify the meadow-watershed connection.

  13. Echo Meadows Project Winter Artificial Recharge.

    SciTech Connect

    Ziari, Fred

    2002-12-19

    This report discusses the findings of the Echo Meadows Project (BPA Project 2001-015-00). The main purpose of this project is to artificially recharge an alluvial aquifer, WITH water from Umatilla River during the winter high flow period. In turn, this recharged aquifer will discharge an increased flow of cool groundwater back to the river, thereby improving Umatilla River water quality and temperature. A considerable side benefit is that the Umatilla River should improve as a habitat for migration, spanning, and rearing of anadromous and resident fish. The scope of this project is to provide critical baseline information about the Echo Meadows and the associated reach of the Umatilla River. Key elements of information that has been gathered include: (1) Annual and seasonal groundwater levels in the aquifer with an emphasis on the irrigation season, (2) Groundwater hydraulic properties, particularly hydraulic conductivity and specific yield, and (3) Groundwater and Umatilla River water quality including temperature, nutrients and other indicator parameters. One of the major purposes of this data gathering was to develop input to a groundwater model of the area. The purpose of the model is to estimate our ability to recharge this aquifer using water that is only available outside of the irrigation season (December through the end of February) and to estimate the timing of groundwater return flow back to the river. We have found through the data collection and modeling efforts that this reach of the river had historically returned as much as 45 cubic feet per second (cfs) of water to the Umatilla River during the summer and early fall. However, this return flow was reduced to as low as 10 cfs primarily due to reduced quantities of irrigation application, gain in irrigation efficiencies and increased groundwater pumping. Our modeling indicated that it is possible to restore these critical return flows using applied water outside of the irrigation season. We further

  14. Montane meadow evapotranspiration: implications for restoration and impacts on downstream flow.

    NASA Astrophysics Data System (ADS)

    Lucas, R. G.; Conklin, M. H.; Goulden, M.

    2015-12-01

    Meadows comprise less than 1 percent of the area in the Sierra Nevada Mountains, CA, but play an important role in hydrologic processes of Sierra catchments. This study constrains meadow evapotranspiration (ET) and places meadow ET in the context of the greater watershed ET. Meadows in the Sierra Nevada range from pristine to restored to degraded—decades of stock grazing, road building, and logging, have left incised stream channels and lowered water tables in many meadow s. The State of California has prioritized meadow restoration; these efforts are motivated, at least in part, as a means to increase groundwater storage (California Water Action Plan; 2014). Information on how restoration affects meadow and catchment hydrology and ET is lacking. We combined eddy covariance measurements (2013 and 2014) and meteorological records (2008 to 2014) with an Artificial Neural Network to quantify meadow ET over a 7 year period. We focused on Long Meadow, which is a pristine meadow located at 2210 m in Sequoia National Park, CA. ET was highest in drought years 2012-2014 (532 mm in 2013) and lowest in a particularly wet year (470 mm), 2011. This trend is opposite that observed for nearby upland Sierra Nevada forest by the SSCZO eddy flux stations, where annual ET declined from wet to dry years. Meadow ET was generally lower and less variable than forest ET. Long Meadow ET is 25-50% greater than ET rates reported in systems similar to degraded meadows such as bitterbrush/sagebrush dominated areas (Mauer et al.; 2006); this ET discrepancy is consistent with previous studies that suggest healthy meadow ET can be 25-50% more than ET in a degraded meadow s (Hammersmark et al.; 2008). Because meadows are a small fraction of the land area, however, restoring meadows to healthy conditions results in only a small increase in ET in the greater watershed. Restoring a meadow similar in size (~4.6 hectares) and associated catchment size (~140 hectares) to Long Meadow from a degraded to

  15. Montane meadows and hydrologic connections between forests and streams in the Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Lucas, R. G.; Conklin, M. H.

    2013-12-01

    Montane meadows of the Sierra Nevada often serve as the interface between up-gradient forested area and down-gradient streamflow. We investigated the roles that meadow groundwater and evapotranspiration play in the greater catchment water cycle using a water-column data from monitoring wells and piezometers in two meadows for water years 2008-2012. Analyses include mass balance and modeling using 1-D HYDRUS. Though spatially heterogeneous, groundwater fluxes contribute to evapotranspiration (ETg) across the meadows, and are constrained by surface-water discharge. Near the meadow center groundwater discharges occur for the duration of the snow-free season, ET¬g is relatively low. At the meadow edge the groundwater flux changes from discharge to recharge when the growing season begins; also ETg increases, and major-ion concentrations in groundwater are more dilute than those near the meadow center. When groundwater is discharged throughout the meadow during snowmelt, the stream-water ion content more closely resembles water sampled from wells at the meadow edge. These trends change as the summer season progresses--groundwater is no longer discharged at the meadow edge and the stream water ion concentration matches the groundwater sampled from the center of the meadow. Slug tests performed in the monitoring wells indicate a saturated hydraulic conductivity (Kh) of meadow substrates between 10-5 and 10-6 m s-1. The upper end of this range reflects substrate with large sand fractions, while lower values reflect finer-grained or higher-organic-content substrate. Applying the higher Kh values to groundwater gradients during snowmelt results in groundwater discharge rates greater than streamflow measured at the meadow outlet. This suggests that the peat layer at the meadow surface, with significantly lower Kh values, retards groundwater discharge from the meadow during snowmelt. ETg signals in wells at the meadow edge and in wells installed just outside of the meadow

  16. Seagrass meadows (Posidonia oceanica) distribution and trajectories of change

    PubMed Central

    Telesca, Luca; Belluscio, Andrea; Criscoli, Alessandro; Ardizzone, Giandomenico; Apostolaki, Eugenia T.; Fraschetti, Simonetta; Gristina, Michele; Knittweis, Leyla; Martin, Corinne S.; Pergent, Gérard; Alagna, Adriana; Badalamenti, Fabio; Garofalo, Germana; Gerakaris, Vasilis; Louise Pace, Marie; Pergent-Martini, Christine; Salomidi, Maria

    2015-01-01

    Posidonia oceanica meadows are declining at alarming rates due to climate change and human activities. Although P. oceanica is considered the most important and well-studied seagrass species of the Mediterranean Sea, to date there has been a limited effort to combine all the spatial information available and provide a complete distribution of meadows across the basin. The aim of this work is to provide a fine-scale assessment of (i) the current and historical known distribution of P. oceanica, (ii) the total area of meadows and (iii) the magnitude of regressive phenomena in the last decades. The outcomes showed the current spatial distribution of P. oceanica, covering a known area of 1,224,707 ha, and highlighted the lack of relevant data in part of the basin (21,471 linear km of coastline). The estimated regression of meadows amounted to 34% in the last 50 years, showing that this generalised phenomenon had to be mainly ascribed to cumulative effects of multiple local stressors. Our results highlighted the importance of enforcing surveys to assess the status and prioritize areas where cost-effective schemes for threats reduction, capable of reversing present patterns of change and ensuring P. oceanica persistence at Mediterranean scale, could be implemented. PMID:26216526

  17. 76 FR 40322 - Mt. Hood Meadows Ski Resort Parking Improvements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-08

    ... disclose the potential environmental effects of improving the parking at Mt. Hood Meadows Ski Resort. The..., cut/fill slopes, storm water swales, snow storage, and an equipment maintenance yard. In addition, the...). An additional 4.5 acres would be cleared for access roads, cut/fill slopes, storm water swales,...

  18. Site Guide to Sunken Meadow State Park. Revised.

    ERIC Educational Resources Information Center

    Palma, Alfred J.

    Sunken Meadow State Park provides a year round three-fold ecosystem (marine beach, salt marsh, and wooded upland) of 1,266 acres for Suffolk County (NY) teachers and students to use as a site for outdoor education activities. While teachers can rely on the support of the Outdoor Learning Laboratories' staff for aid in emergencies, for clarifying…

  19. Bibliography of Writings by A.J. Meadows.

    ERIC Educational Resources Information Center

    Line, Maurice B.

    2000-01-01

    This chronological bibliography of writings (1967-1999) by A.J. Meadows, astronomer, historian of science, and information scientist, is restricted to papers and book reviews on library and information science, publishing and scientific communication. It excludes works on the history of science and astronomy. It aims at completeness, though some…

  20. Truckee Meadows Community College FactBook, 2002.

    ERIC Educational Resources Information Center

    Truckee Meadows Community Coll., Sparks, NV.

    The Truckee Meadows Community College 2002 FactBook summarizes institutional data pertaining to enrollment trends, student profiles, institutional outcome measures, campus resources, and the external environment. The institution had a total enrollment of 10,445 students (17 percent of whom were full-time and 36 percent part-time and attending…

  1. The Just Community at Birch Meadow Elementary School.

    ERIC Educational Resources Information Center

    Murphy, Dennis F.

    1988-01-01

    Six years ago, students at Birch Meadow Elementary School (Reading, Massachusetts) were polite to adults, but callous and uncaring toward each other. Today, thanks to a "Just Community" approach modeled on Lawrence Kohlberg's philosophy, students feel a sense of school ownership and responsibility for their classmates. (MLH)

  2. A.J. (Jack) Meadows: A Biographical Note.

    ERIC Educational Resources Information Center

    Line, Maurice B.

    2000-01-01

    Presents a brief sketch of A.J. (Jack) Meadows's career. Notes that he has written many significant articles and books in information science and related fields, many of them of seminal importance. Highlights his contributions to the field and to the many people who have worked with him. (AEF)

  3. 6. VIEW OF COULTERVILLE ROAD AT BIG MEADOW IN FORESTA. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW OF COULTERVILLE ROAD AT BIG MEADOW IN FORESTA. INTERSECTION WITH DAVIS CUT-OFF ROAD AT LEFT. LOOKING W. GIS: N-37 42 09.3 / W-119 44 59.8 - Coulterville Road, Between Foresta & All-Weather Highway, Yosemite Village, Mariposa County, CA

  4. 66. BIG MEADOWS. VIEW OF PARKING AREA AT THE GATED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    66. BIG MEADOWS. VIEW OF PARKING AREA AT THE GATED ENTRANCE TO RAPIDAN FIRE ROAD, THE ACCESS ROAD TO CAMP HOOVER. LOOKING SOUTH, MILE 51.3. - Skyline Drive, From Front Royal, VA to Rockfish Gap, VA , Luray, Page County, VA

  5. How sedge meadow soils, microtopography, and vegetation respond to sedimentation

    USGS Publications Warehouse

    Werner, K.J.; Zedler, Joy B.

    2002-01-01

    The expansion of urban and agricultural activities in watersheds of the Midwestern USA facilitates the conversion of species-rich sedge meadows to stands of Phalaris arundinacea and Typha spp. We document the role of sediment accumulation in this process based on field surveys of three sedge meadows dominated by Carex stricta, their adjacent Phalaris or Typha stands, and transitions from Carex to these invasive species. The complex microtopography of Carex tussocks facilitates the occurrence of other native species. Tussock surface area and species richness were positively correlated in two marshes (r2 = 0.57 and 0.41); on average, a 33-cm-tall tussock supported 7.6 species. Phalaris also grew in tussock form in wetter areas but did not support native species. We found an average of 10.5 Carex tussocks per 10-m transect, but only 3.5 Phalaris tussocks. Microtopographic relief, determined with a high-precision GPS, measured 11% greater in Carex meadows than Phalaris stands. Inflowing sediments reduced microtopographic variation and surface area for native species. We calculated a loss of one species per 1000 cm2 of lost tussock surface area, and loss of 1.2 species for every 10-cm addition of sediment over the sedge meadow surface. Alluvium overlying the sedge meadow soil had a smaller proportion of organic matter content and higher dry bulk density than the buried histic materials. We conclude that sedimentation contributes to the loss of native species in remnant wetlands. ?? 2002, The Society of Wetland Scientists.

  6. A Water Budget Approach to Study the Hydrologic Response of Mountain Meadow Restoration Following Conifer Removal

    NASA Astrophysics Data System (ADS)

    Van Oosbree, G. F.; Surfleet, C. G.; Jasbinsek, J. J.

    2014-12-01

    Mountain meadows are important ecological habitats that have degraded in quality and distribution due to fire suppression and poor land use practices in the Sierra Nevada Mountains. Conifer encroachment in mountain meadows has accelerated and is one of the reasons for the decline of meadow habitat. To date there are few studies which quantify the hydrologic response of meadow restoration due to vegetation or conifer removal. This study is using a before after control intervention (BACI) study design to determine the hydrologic response of restoration to a historic meadow encroached by conifers (study meadow). A water budget approach has been developed to quantify the hydrology of the control and study meadow before and after restoration. Measurements of groundwater depth and soil moisture are currently being taken on the control and study meadows. A total of 14 Odyssey water level capacitance instruments were installed to a 1.5 meter depth and 14 soil moisture instruments were installed to a 30 cm depth using a spatially balanced random sampling approach. Electrical resistivity imaging (ERI) was used to determine soil moisture and depth to groundwater across forest-meadow ecotones present on the meadows. Additionally, ERI was used to extrapolate point measurements of groundwater depth and soil moisture across the study and control areas. The weekly water budget indicates differences between the control meadow and study meadow in the first year prior to conifer removal. The ERI indicated differences in sub surface geology, soil moisture, and groundwater depth both between the control and study meadows and along the forest-meadow ecotones. ERI was demonstrated to improve the spatial extrapolation of soil moisture and groundwater point measurements.

  7. Characterizing the Source Water for Montane Meadows to Assess Resiliency under Changing Hydroclimatic Condition

    NASA Astrophysics Data System (ADS)

    Yarnell, S. M.; Peek, R.; Bell, A.; Weixelman, D.; Viers, J. H.

    2015-12-01

    Ecologically and hydrologically functioning montane meadows provide a variety of ecosystem services and create biological hotspots in high-elevation landscapes. They serve as wetlands that filter water, attenuate floods, sequester carbon, sustain downstream flows, and provide high productivity habitat in typically lower productivity mountain regions. Their importance to watershed quality and health is well recognized, and restoration of meadows is a high priority for resource management agencies and non-governmental organizations. Yet many meadow restoration projects have limited outcomes or fail to achieve the desired effects due to a lack of understanding the underlying hydrological and geomorphic processes inherent to meadows that contribute to their resiliency. Few studies exist on how meadows are sustained through time despite various land use impacts or how the origin of water supplying the meadow (snowmelt-dominated versus regional groundwater-dominated) may influence meadow conditions. Furthermore, as climate conditions continue to change, questions remain regarding which meadows will be most resistant to and resilient from climate warming and thus have the highest potential for successful and sustainable restoration of meadow processes. We discuss these concepts and present two methods for assessing the regional and local contributions of source water to meadows as an indicator of resiliency. On a broad scale, comparisons of satellite imagery using metrics such as normalized difference vegetation index (NDVI) for regions with meadows may be useful to detect inter-annual and seasonal variations in meadow wetness and thus indicate meadow sites with larger groundwater sources that are more resilient over time. Locally, use of a hydrogeomorphic typing key that relates water source, geomorphic position, groundwater table elevation, and plant species composition may be useful to detect local groundwater sources that provide greater consistency of conditions and

  8. Meadow degradation, hydrological processes and rangeland management in Tibet

    NASA Astrophysics Data System (ADS)

    He, Siyuan; Richards, Keith

    2013-04-01

    Alpine meadow dominated by species of Kobresia is widely distributed in the Tibetan Plateau. Kobresia pygmaea is often a main species and the meadow has evolved as a result of long-term trampling, being a main rangeland resource for livestock grazing. This alpine meadow also plays an important role in regulating the water and energy balance through land-atmosphere interaction, leaving an impact on local hydrological processes and beyond. Therefore, alpine meadow degradation is detrimental to both the health of the ecosystems, and to pastoralism. This research therefore studies the hydrological process with regard to degradation of Kobresia pygmaea meadow, tracing the possible causes, detecting the impacts on soil and biological properties, and further considering the herders' role in future rangeland management. The study area is around the Kema village of the Nagqu Prefecture in Northern Tibet, where human population depends on livestock grazing for livelihood. Main driving factors of alpine meadow degradation are climatic variations and human disturbance. The periodical change in local climate may be related to quasi-oscillatory atmospheric circulations in this monsoon dominated area and the climatic trends with extreme weather conditions can make the whole system hard to recover. Along with climatic variations, overgrazing is predominant with an exceeding of the carrying capacity by almost every household in this village. This is related to the change of rangeland management by the policies of privatisation of pasture and sedentarisation. The acceleration of degradation since the 1980s results in a series of distinct soil-vegetation combination classified in this research as the normal meadow, compact crust and bare soil. The species composition, soil physical and chemical properties and the vertical water movement along the soil-plant-atmosphere continuum are significantly different at the sites representing stages of degradation, revealed by multiple methods

  9. 39. View of the big meadow of the Billings Farm ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. View of the big meadow of the Billings Farm & Museum, looking east from Vt. Route 12 (Elm Street). The view includes Blake Hill on the horizon, the Billings Farm & Museum's restored historic apple orchard at left, and the property of the Octagon Cottage at 4 Moore Place, beyond the split rail fence at right. - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

  10. 60. View of the big meadow of the Billings Farm ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. View of the big meadow of the Billings Farm & Museum, looking east from Vt. Route 12 (Elm Street). The view includes Blake Hill on the horizon, the Billings Farm & Museum's restored historic apple orchard at left, and the property of the Octagon Cottage at 4 Moore Place, beyond the split rail fence at right. - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

  11. Variation in winter snowpack depth and duration influences summer soil respiration in a subalpine meadow

    NASA Astrophysics Data System (ADS)

    Arnold, C. L.; Ghezzehei, T. A.; Berhe, A. A.

    2012-12-01

    Subalpine meadows in the Sierra Nevada rely on the depth and duration of the winter snowpack to supply ample water to restore the water table in the meadow during the spring snowmelt. This study examines the role that interannual variability in the winter snowpack plays in the overall rate of summer soil respiration along a hydrologic gradient in a subalpine meadow. Carbon dioxide efflux from the meadow was measured from June through September in 2011 and 2012 using soil collars and a LICOR 8100A infrared gas analyzer. Preliminary results show that soil respiration rates are influenced by the hydrologic gradient across the meadow, with drier regions peaking earlier in the summer as compared to wetter regions. We also show that high snowpack years can suppress soil respiration in the meadow until late in the summer season as compared to low snowpack years, where soil respiration peaks early in the summer.

  12. Traditional Livelihoods, Conservation and Meadow Ecology in Jiuzhaigou National Park, Sichuan, China

    PubMed Central

    Urgenson, Lauren; Schmidt, Amanda H.; Combs, Julie; Harrell, Stevan; Hinckley, Thomas; Yang, Qingxia; Ma, Ziyu; Yongxian, Li; Hongliang, Lü; MacIver, Andrew

    2015-01-01

    Jiuzhaigou National Park (JNP) is a site of global conservation significance. Conservation policies in JNP include the implementation of two national reforestation programs to increase forest cover and the exclusion of local land-use. We use archaeological excavation, ethnographic interviews, remote sensing and vegetation surveys to examine the implications of these policies for non-forest, montane meadows. We find that Amdo Tibetan people cultivated the valley for >2,000 years, creating and maintaining meadows through land clearing, burning and grazing. Meadows served as sites for gathering plants and mushrooms and over 40 % of contemporary species are ethnobotanically useful. Remote sensing analyses indicate a substantial (69.6 %) decline in meadow area between 1974 and 2004. Respondents report a loss of their “true history” and connections to the past associated with loss of meadows. Conservation policies intended to preserve biodiversity are unintentionally contributing to the loss of these ecologically and culturally significant meadow habitats. PMID:26097267

  13. Seagrass meadows as a globally significant carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Mazarrasa, I.; Marbà, N.; Lovelock, C. E.; Serrano, O.; Lavery, P. S.; Fourqurean, J. W.; Kennedy, H.; Mateo, M. A.; Krause-Jensen, D.; Steven, A. D. L.; Duarte, C. M.

    2015-08-01

    There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha-1, with an average of 654 ± 24 Mg PIC ha-1, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of -8 ± 2 Mg PIC ha-1 per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m-2 yr-1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr-1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrated by the comparison of carbon (PIC

  14. Ecohydrological controls over water budgets in floodplain meadows

    NASA Astrophysics Data System (ADS)

    Morris, Paul J.; Verhoef, Anne; Macdonald, David M. J.; Gardner, Cate M.; Punalekar, Suvarna M.; Tatarenko, Irina; Gowing, David

    2013-04-01

    Floodplain meadows are important ecosystems, characterised by high plant species richness including rare species. Fine-scale partitioning along soil hydrological gradients allows many species to co-exist. Concerns exist that even modest changes to soil hydrological regime as a result of changes in management or climate may endanger floodplain meadows communities. As such, understanding the interaction between biological and physical controls over floodplain meadow water budgets is important to understanding their likely vulnerability or resilience. Floodplain meadow plant communities are highly heterogeneous, leading to patchy landscapes with distinct vegetation. However, it is unclear whether this patchiness in plant distribution is likely to translate into heterogeneous soil-vegetation-atmosphere transfer (SVAT) rates of water and heat, or whether floodplain meadows can reasonably be treated as internally homogeneous in physical terms despite this patchy vegetation. We used a SVAT model, the Soil-Water-Atmosphere-Plants (SWAP) model by J.C. van Dam and co-workers, to explore the controls over the partitioning of water budgets in floodplain meadows. We conducted our research at Yarnton Mead on the River Thames in Oxfordshire, one of the UK's best remaining examples of a floodplain meadow, and which is still managed and farmed in a low-intensity mixed-use manner. We used soil and plant data from our site to parameterise SWAP; we drove the model using in-situ half-hourly meteorological data. We analysed the model's sensitivity to a range of soil and plant parameters - informed by our measurements - in order to assess the effects of different plant communities on SVAT fluxes. We used a novel method to simulate water-table dynamics at the site; the simulated water tables provide a lower boundary condition for SWAP's hydrological submodel. We adjusted the water-table model's parameters so as to represent areas of the mead with contrasting topography, and so different

  15. Invasion of subalpine meadows by lodgepole pine in Yellowstone National Park, Wyoming, USA

    SciTech Connect

    Jakubos, B.; Romme, W.H. )

    1993-11-01

    Many of the dry and mesic subalpine meadows in Yellowstone National Park are bordered by bands of small lodgepole pine trees. The authors asked whether these stands of small trees represent a directional process of meadow invasion, or alternatively, (1) small patches of postfire succession or; (2) more-or-less stable populations of trees having small stature because of adverse site conditions. Transect studies revealed that the bands of small trees were consistently younger than adjacent forest stands of obvious fire origin, that they lacked any evidence of fire, and that the trees were progressively younger as they approached the meadow. Soils under the young trees generally were more similar to meadow soils than to coniferous forest soils. The authors concluded, therefore, that meadow invasion has been occurring as a directional process since at least the mid- to late 1800s. Frequency of tree establishment in two dry meadows was positively correlated with mean June temperature and total summer precipitation (R[sup 2] = 0.49, P<0.0001, multiple stepwise regression). Thus, the major cause of tree invasion into dry meadows appears to be a regional climatic trend towards warmer and wetter growing seasons since the end of the Little Ice Age. Tree establishment in two mesic meadows was more weakly and inconsistently correlated with weather variables. Thus, the mechanism of invasion of mesic meadows may involve interactions of episodic seed crops and microhabitat changes at the forest border, as well as regional climatic variability. 30 refs., 7 figs., 1 tab.

  16. Twenty Years of "Plug-and-Pond" Meadow Restoration: A Geomorphic Review

    NASA Astrophysics Data System (ADS)

    Natali, J.

    2015-12-01

    Channel incision has degraded the ecological function of wet meadows across montane regions of California. Conservation groups estimate that half of the Sierra Nevada's 333,000 acres of meadow are entrenched in a degraded state that is characterized by a shift from groundwater­fed, herbaceous vegetation to more sparse, drought­tolerant woody vegetation. My poster will present results of field research on a prominent restoration technique in California's montane meadows, the "Plug­and­Pond." Fundamentally, the technique re­channelizes the meadow by blocking flow into incised stream channels. Spoils dug from meadow sediments plug the incised channel, creating ponds as a by­product. One of three approaches to re­channelization ensues: (1) construct a new shallow and sinuous channel, (2) redirect flows into a remnant channel, (3) or allow the channel to define itself over the meadow floodplain. Re­ channelization aims to support overbank flows at 1.5 to 3 year recurrence intervals. Field surveys of ten of the oldest "plug-and-pond" meadow restoration projects in California reveal that channel bed degradation caused by meadow-scale changes to channel slope (i.e. culverts concentrating flows, channel straightening, meadow grazing) may be more conducive to intensive restoration approaches like Plug-and-Pond.

  17. Ground Water Modeling to Evaluate a Planned Restoration of a Montane Meadow

    NASA Astrophysics Data System (ADS)

    Curtis, C.

    2014-12-01

    Meadows are biologically diverse systems where a melting pot of hydrologic, geologic, and ecologic conditions cumulate. Due to their lush vegetation, water resources, and cool temperature meadows have long been utilized for human use. Through neglectful practices and extreme weather events meadows across the west have been degraded. Round Meadow, located 4 km southwest of Pinecrest Lake in the Stanislaus National Forest in California suffered a severe flood in the 1960's which largely contributed to its current degraded state. To restore Round Meadow's natural ecohydrologic functions a meadow restoration has been planned. In this research, MODFLOW models are linked with R script to simulate the snowmelt, streamflow and groundwater flow at Round Meadow. HyperNiche2 is used to model foliar cover. Two versions of "pond and plug" restoration are simulated without and with a divergent stream channel. It is found that moist meadow cover is increased by 0.61 and 1.32 hectares respectively over degraded conditions. The meadow aquifer was recharged as result of restorations and modeling suggests increased late year base flows.

  18. Net primary productivity of subalpine meadows in Yosemite National Park in relation to climate variability

    USGS Publications Warehouse

    Moore, Peggy E.; Van Wagtendonk, Jan W.; Yee, Julie L.; McClaran, Mitchel P.; Cole, David N.; McDougald, Neil K.; Brooks, Matthew L.

    2013-01-01

    Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate. Our objective was to describe patterns and variability in aboveground live vascular plant biomass in relation to climatic factors. We harvested aboveground biomass at peak growth from four 64-m2 plots each in xeric, mesic, and hydric meadows annually from 1994 to 2000. Data from nearby weather stations provided independent variables of spring snow water content, snow-free date, and thawing degree days for a cumulative index of available energy. We assembled these climatic variables into a set of mixed effects analysis of covariance models to evaluate their relationships with annual aboveground net primary productivity (ANPP), and we used an information theoretic approach to compare the quality of fit among candidate models. ANPP in the xeric meadow was negatively related to snow water content and thawing degree days and in the mesic meadow was negatively related to snow water content. Relationships between ANPP and these 2 covariates in the hydric meadow were not significant. Increasing snow water content may limit ANPP in these meadows if anaerobic conditions delay microbial activity and nutrient availability. Increased thawing degree days may limit ANPP in xeric meadows by prematurely depleting soil moisture. Large within-year variation of ANPP in the hydric meadow limited sensitivity to the climatic variables. These relationships suggest that, under projected warmer and drier conditions, ANPP will increase in mesic meadows but remain unchanged in xeric meadows because declines associated with increased temperatures would offset the increases from decreased snow water content.

  19. Cattle Grazing and Conservation of a Meadow-Dependent Amphibian Species in the Sierra Nevada

    PubMed Central

    Roche, Leslie M.; Latimer, Andrew M.; Eastburn, Danny J.; Tate, Kenneth W.

    2012-01-01

    World-wide population declines have sharpened concern for amphibian conservation on working landscapes. Across the Sierra Nevada's national forest lands, where almost half of native amphibian species are considered at risk, permitted livestock grazing is a notably controversial agricultural activity. Cattle (Bos taurus) grazing is thought to degrade the quality, and thus reduce occupancy, of meadow breeding habitat for amphibian species of concern such as the endemic Yosemite toad (Anaxyrus [ = Bufo] canorus). However, there is currently little quantitative information correlating cattle grazing intensity, meadow breeding habitat quality, and toad use of meadow habitat. We surveyed biotic and abiotic factors influencing cattle utilization and toad occupancy across 24 Sierra Nevada meadows to establish these correlations and inform conservation planning efforts. We utilized both traditional regression models and Bayesian structural equation modeling to investigate potential drivers of meadow habitat use by cattle and Yosemite toads. Cattle use was negatively related to meadow wetness, while toad occupancy was positively related. In mid and late season (mid July–mid September) grazing periods, cattle selected for higher forage quality diets associated with vegetation in relatively drier meadows, whereas toads were more prevalent in wetter meadows. Because cattle and toads largely occupied divergent zones along the moisture gradient, the potential for indirect or direct negative effects is likely minimized via a partitioning of the meadow habitat. During the early season, when habitat use overlap was highest, overall low grazing levels resulted in no detectable impacts on toad occupancy. Bayesian structural equation analyses supported the hypothesis that meadow hydrology influenced toad meadow occupancy, while cattle grazing intensity did not. These findings suggest cattle production and amphibian conservation can be compatible goals within this working

  20. Groundwater Surface Trends at Van Norden Meadow, California, from Ground Penetrating Radar Profiles

    NASA Astrophysics Data System (ADS)

    Tadrick, N. I.; Blacic, T. M.; Yarnell, S. M.

    2014-12-01

    Van Norden meadow in the Donner Summit area west of Lake Tahoe is one of the largest sub-alpine meadows in the Sierra Nevada mountain range. As natural water retention basins, meadows attenuate floods, improve water quality and support vegetation that stabilizes stream banks and promotes high biodiversity. Like most meadows in the Sierras however, over-grazing, road-building, and development has resulted in localized stream incision, degradation, and partial conversion from wet to dry conditions in Van Norden. Additionally, a small dam at the base of the meadow has partially flooded the lower meadow creating reservoir conditions. Privately owned since the late 1800s, Van Norden was recently purchased by a local land trust to prevent further development and return the area to public ownership. Restoration of the natural meadow conditions will involve notching the dam in 2016 to reduce currently impounded water volumes from 250 to less than 50 acre-feet. To monitor the effects of notching the dam on the upstream meadow conditions, better understanding of the surface and groundwater hydrology both pre- and post-restoration is required. We surveyed the meadow in summer 2014 with ground penetrating radar (GPR) to map the groundwater surface prior to restoration activities using a 270MHz antenna to obtain a suite of longitudinal and transverse transects. Groundwater level within the meadow was assessed using both piezometer readings and sweeps of the GPR antenna. Seventeen piezometers were added this year to the 13 already in place to monitor temporal changes in the groundwater surface, while the GPR profiles provided information about lateral variations. Our results provide an estimate of the groundwater depth variations across the upper portion of the meadow before notching. We plan to return in 2015 to collect GPR profiles during wetter conditions, which will provide a more complete assessment of the pre-notching groundwater hydrology.

  1. Cattle grazing and conservation of a meadow-dependent amphibian species in the Sierra Nevada.

    PubMed

    Roche, Leslie M; Latimer, Andrew M; Eastburn, Danny J; Tate, Kenneth W

    2012-01-01

    World-wide population declines have sharpened concern for amphibian conservation on working landscapes. Across the Sierra Nevada's national forest lands, where almost half of native amphibian species are considered at risk, permitted livestock grazing is a notably controversial agricultural activity. Cattle (Bos taurus) grazing is thought to degrade the quality, and thus reduce occupancy, of meadow breeding habitat for amphibian species of concern such as the endemic Yosemite toad (Anaxyrus [ = Bufo] canorus). However, there is currently little quantitative information correlating cattle grazing intensity, meadow breeding habitat quality, and toad use of meadow habitat. We surveyed biotic and abiotic factors influencing cattle utilization and toad occupancy across 24 Sierra Nevada meadows to establish these correlations and inform conservation planning efforts. We utilized both traditional regression models and Bayesian structural equation modeling to investigate potential drivers of meadow habitat use by cattle and Yosemite toads. Cattle use was negatively related to meadow wetness, while toad occupancy was positively related. In mid and late season (mid July-mid September) grazing periods, cattle selected for higher forage quality diets associated with vegetation in relatively drier meadows, whereas toads were more prevalent in wetter meadows. Because cattle and toads largely occupied divergent zones along the moisture gradient, the potential for indirect or direct negative effects is likely minimized via a partitioning of the meadow habitat. During the early season, when habitat use overlap was highest, overall low grazing levels resulted in no detectable impacts on toad occupancy. Bayesian structural equation analyses supported the hypothesis that meadow hydrology influenced toad meadow occupancy, while cattle grazing intensity did not. These findings suggest cattle production and amphibian conservation can be compatible goals within this working landscape

  2. Effects of disturbance regime on carbohydrate reserves in meadow plants.

    PubMed

    Janeček, Štěpán; Bartušková, Alena; Bartoš, Michael; Altman, Jan; de Bello, Francesco; Doležal, Jiří; Latzel, Vít; Lanta, Vojtěch; Lepš, Jan; Klimešová, Jitka

    2015-10-27

    Carbohydrate storage enables plants to tolerate both seasonally unfavourable conditions and recover from disturbance. Although short-term changes in storage levels due to disturbance are fairly well known, less is known about long-term changes in storage levels, especially in response to cessation of repeated disturbance. Additionally, whereas it is presumably the total amount (pool) of storage carbohydrate reserves that is of importance, typically carbohydrate concentrations are measured instead, as a proxy. We assessed changes in carbohydrate concentrations and pools in storage organs and changes in above- versus belowground biomass in response to mowing cessation in nine herbs from two meadows (dry and wet) at the (June) peak of vegetation development and the (October) growing season end 1 and 3 years after the change in the disturbance regime. We tested three hypotheses: (1) storage will increase with abandonment of mowing only in the first year after disturbance cessation, but not further increase subsequently, as high storage would hinder competitive ability; (2) storage will increase towards the end of the season in both disturbed and undisturbed plants; and (3) changes in carbohydrate concentrations are accurate predictors of changes in pools. Although species-specific changes in carbohydrate reserves occurred in the wet meadow, more general trends appeared in the dry meadow. There, plants accumulated higher carbohydrate reserves at the end of the season, especially in unmown plots. However, the reserves for plants in both disturbance regimes were the same at the growing season peak (June) in both examined years. The increase in storage of carbohydrates on unmown plots in October was manifested by increases of both storage organ biomass and carbohydrate concentration, whereas in mown plots, it was due only to increased carbohydrate concentration. Although concentrations and pools represent different aspects of plant carbohydrate economy, concentrations will

  3. Effects of disturbance regime on carbohydrate reserves in meadow plants

    PubMed Central

    Janeček, Štěpán; Bartušková, Alena; Bartoš, Michael; Altman, Jan; de Bello, Francesco; Doležal, Jiří; Latzel, Vít; Lanta, Vojtěch; Lepš, Jan; Klimešová, Jitka

    2015-01-01

    Carbohydrate storage enables plants to tolerate both seasonally unfavourable conditions and recover from disturbance. Although short-term changes in storage levels due to disturbance are fairly well known, less is known about long-term changes in storage levels, especially in response to cessation of repeated disturbance. Additionally, whereas it is presumably the total amount (pool) of storage carbohydrate reserves that is of importance, typically carbohydrate concentrations are measured instead, as a proxy. We assessed changes in carbohydrate concentrations and pools in storage organs and changes in above- versus belowground biomass in response to mowing cessation in nine herbs from two meadows (dry and wet) at the (June) peak of vegetation development and the (October) growing season end 1 and 3 years after the change in the disturbance regime. We tested three hypotheses: (1) storage will increase with abandonment of mowing only in the first year after disturbance cessation, but not further increase subsequently, as high storage would hinder competitive ability; (2) storage will increase towards the end of the season in both disturbed and undisturbed plants; and (3) changes in carbohydrate concentrations are accurate predictors of changes in pools. Although species-specific changes in carbohydrate reserves occurred in the wet meadow, more general trends appeared in the dry meadow. There, plants accumulated higher carbohydrate reserves at the end of the season, especially in unmown plots. However, the reserves for plants in both disturbance regimes were the same at the growing season peak (June) in both examined years. The increase in storage of carbohydrates on unmown plots in October was manifested by increases of both storage organ biomass and carbohydrate concentration, whereas in mown plots, it was due only to increased carbohydrate concentration. Although concentrations and pools represent different aspects of plant carbohydrate economy, concentrations will

  4. Interoperability challenges for the Sustainable Management of seagrass meadows (Invited)

    NASA Astrophysics Data System (ADS)

    Nativi, S.; Pastres, R.; Bigagli, L.; Venier, C.; Zucchetta, M.; Santoro, M.

    2013-12-01

    Seagrass meadows (marine angiosperm plants) occupy less than 0.2% of the global ocean surface, annually store about 10-18% of the so-called 'Blue Carbon', i.e. the Carbon stored in coastal vegetated areas. Recent literature estimates that the flux to the long-term carbon sink in seagrasses represents 10-20% of seagrasses global average production. Such figures can be translated into economic benefits, taking into account that a ton of carbon dioxide in Europe is paid at around 15 € in the carbon market. This means that the organic carbon retained in seagrass sediments in the Mediterranean is worth 138 - 1128 billion €, which represents 6-23 € per square meter. This is 9-35 times more than one square meter of tropical forest soil (0.66 € per square meter), or 5-17 times when considering both the above and the belowground compartments in tropical forests. According the most conservative estimations, about 10% of the Mediterranean meadows have been lost during the last century. In the framework of the GEOSS (Global Earth Observation System of Systems) initiative, the MEDINA project (funded by the European Commission and coordinated by the University of Ca'Foscari in Venice) prepared a showcase as part of the GEOSS Architecture Interoperability Pilot -phase 6 (AIP-6). This showcase aims at providing a tool for the sustainable management of seagrass meadows along the Mediterranean coastline. The application is based on an interoperability framework providing a set of brokerage services to easily ingest and run a Habitat Suitability model (a model predicting the probability a given site to provide a suitable habitat for the development of seagrass meadow and the average coverage expected). The presentation discusses such a framework explaining how the input data is discovered, accessed and processed to ingest the model (developed in the MEDINA project). Furthermore, the brokerage framework provides the necessary services to run the model and visualize results

  5. Sustainable Management of Seagrass Meadows: the GEOSS AIP-6 Pilot

    NASA Astrophysics Data System (ADS)

    Santoro, Mattia; Pastres, Roberto; Zucchetta, Matteo; Venier, Chiara; Roncella, Roberto; Bigagli, Lorenzo; Mangin, Antoine; Amine Taji, Mohamed; Gonzalo Malvarez, Gonzalo; Nativi, Stefano

    2014-05-01

    Seagrass meadows (marine angiosperm plants) occupy less than 0.2% of the global ocean surface, annually store about 10-18% of the so-called "Blue Carbon", i.e. the Carbon stored in coastal vegetated areas. Recent literature estimates that the flux to the long-term carbon sink in seagrasses represents 10-20% of seagrasses global average production. Such figures can be translated into economic benefits, taking into account that a ton of carbon dioxide in Europe is paid at around 15 € in the carbon market. This means that the organic carbon retained in seagrass sediments in the Mediterranean is worth 138 - 1128 billion €, which represents 6-23 € per square meter. This is 9-35 times more than one square meter of tropical forest soil (0.66 € per square meter), or 5-17 times when considering both the above and the belowground compartments in tropical forests. According the most conservative estimations, about 10% of the Mediterranean meadows have been lost during the last century. To estimate seagrass meadows distribution, a Species Distribution Model (SDM) can be used. SDM is a tool that is used to evaluate the potential distribution of a given species (e.g. Posidonia oceanica for seagrass) on the basis of the features (bio-chemical-physical parameters) of the studied environment. In the framework of the GEOSS (Global Earth Observation System of Systems) initiative, the FP7 project MEDINA developed a showcase as part of the GEOSS Architecture Interoperability Pilot - phase 6 (AIP-6). The showcase aims at providing a tool for the sustainable management of seagrass meadows along the Mediterranean coastline by integrating the SDM with available GEOSS resources. This way, the required input data can be searched, accessed and ingested into the model leveraging the brokering framework of the GEOSS Common Infrastructure (GCI). This framework is comprised of a set of middle-ware components (Brokers) that are in charge of implementing the needed interoperability

  6. Impact of a lowered water table on water holding capacity of high elevation meadow soils

    NASA Astrophysics Data System (ADS)

    Arnold, C. L.

    2011-12-01

    Meadow degradation, as a product of overgrazing or disruption of hydrologic regime, is a critical problem facing a variety of environments, including high elevation ecosystems of the Sierra Nevada, California and has become a focus of major research and restoration efforts. Within the historic range of water level in a meadow, it is hypothesized that a meadow will retain its water holding capacity and resiliency. However, if the water table drops below a historic level, due to climate change and/or management practices, the process of soil consolidation will influence the resiliency of the meadow through the irreversible plastic deformation of the soil pores. The subsequent change in soil structure results in decreased porosity, increased bulk density, and a reduction in permeability of the meadow. Such changes can adversely impact the overall water holding capacity of the meadow. This study utilizes a modified triaxial system combined with a multiphysics modeling approach to quantify the historic limit of dryness experienced in a high elevation meadow and degree of consolidation the meadow would experience if that limit was exceeded.

  7. DISTRIBUTION AND QUALITY OF SEAGRASS MEADOWS IN THE PENSACOLA BAY SYSTEM

    EPA Science Inventory

    Abstract for oral presentation: Seagrass meadows have 22 ecological benefits and have an estimated value of $20,500 per acre in Florida. Seagrass meadows support a variety of marine life that includes macroalgae (148 species), epiphytes (1 13 species), macroinvertebrates (230 spe...

  8. 76 FR 46852 - Panasonic Corporation of North America, Business Operations Group, Rolling Meadows, IL; Panasonic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-03

    .... The Notice was published in the Federal Register on April 22, 2011 (76 FR 22731). At the request of a..., Rolling Meadows, IL; Panasonic Corporation of North America, Financial Services Organization, Rolling Meadows, IL; Amended Certification Regarding Eligibility To Apply for Worker Adjustment Assistance...

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  10. 75 FR 39037 - Crane Meadows National Wildlife Refuge, Morrison County, MN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... continue the CCP process for Crane Meadows NWR, which we began by publishing a notice of intent on (73 FR... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Fish and Wildlife Service Crane Meadows National Wildlife Refuge, Morrison County, MN AGENCY: Fish...

  11. 75 FR 63505 - Crane Meadows National Wildlife Refuge, Morrison County, MN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-15

    ... Crane Meadows NWR, which we began by publishing a notice of intent on (73 FR 76677- 76678, December 17... EA to the public, announcing and requesting comments in a notice of availability on (75 FR 39037... Fish and Wildlife Service Crane Meadows National Wildlife Refuge, Morrison County, MN AGENCY: U.S....

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

    PubMed

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

    2015-11-01

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

  13. GROUND WATER/SURFACE WATER INTERACTIONS IN A GREAT BASIN WET MEADOW ECOSYSTEM

    EPA Science Inventory

    Riparian corridors within upland watersheds of the Great Basin locally contain wet meadow ecosystems that support much of the region's biodiversity. Plant communities in these riparian and wet meadow ecosystems can be highly dependent on the depth to and fluctuations in the water...

  14. The role of current velocity in structuring eelgrass ( Zostera marina L.) meadows

    NASA Astrophysics Data System (ADS)

    Fonseca, Mark S.; Zieman, Joseph C.; Thayer, Gordon W.; Fisher, John S.

    1983-10-01

    Measurements of velocity profiles, bathymetry, and surface sediment characteristics across eelgrass ( Zostera marina L.) meadows yielded information on community development processes and functional attributes of this ecosystem. Height/length ratios of the meadows were positively correlated with tidal current velocity. Low, medium, and high current regimes were separated by surface current velocities of approximately 50 and 90 cm s -1. Z. marina can tolerate approximately 120-150 cm/sec current velocities in the areas studied. Per cent silt-clay and organic matter content of the surface sediments are negatively associated with shear velocity, suggesting that meadows in high current areas are sources while meadows in low current areas are sinks of autochthonous detritus. Current velocity maintains seagrass meadows at different equilibrium levels (relative climaxes). We theorize these different equilibrium levels provide unequal habitat utilization potentials for the associated faunal community.

  15. Continuous 1985-2012 Landsat monitoring to assess fire effects on meadows in Yosemite National Park, California

    USGS Publications Warehouse

    Soulard, Christopher E.; Albano, Christine M.; Villarreal, Miguel; Walker, Jessica

    2016-01-01

    To assess how montane meadow vegetation recovered after a wildfire that occurred in Yosemite National Park, CA in 1996, Google Earth Engine image processing was applied to leverage the entire Landsat Thematic Mapper archive from 1985 to 2012. Vegetation greenness (normalized difference vegetation index [NDVI]) was summarized every 16 days across the 28-year Landsat time series for 26 meadows. Disturbance event detection was hindered by the subtle influence of low-severity fire on meadow vegetation. A hard break (August 1996) was identified corresponding to the Ackerson Fire, and monthly composites were used to compare NDVI values and NDVI trends within burned and unburned meadows before, immediately after, and continuously for more than a decade following the fire date. Results indicate that NDVI values were significantly lower at 95% confidence level for burned meadows following the fire date, yet not significantly lower at 95% confidence level in the unburned meadows. Burned meadows continued to exhibit lower monthly NDVI in the dormant season through 2012. Over the entire monitoring period, the negative-trending, dormant season NDVI slopes in the burned meadows were also significantly lower than unburned meadows at 90% confidence level. Lower than average NDVI values and slopes in the dormant season compared to unburned meadows, coupled with photographic evidence, strongly suggest that evergreen vegetation was removed from the periphery of some meadows after the fire. These analyses provide insight into how satellite imagery can be used to monitor low-severity fire effects on meadow vegetation.

  16. UTILIZATION OF IN-STREAM STRUCTURES FOR WET MEADOW STABILIZATION IN THE CENTRAL GREAT BASIN: A PROCESS-ORIENTED APPROACH

    EPA Science Inventory

    Wet meadows, riparian corridor phreatophyte assemblages, and high-altitude spring-fed aspen meadows all serve as important habitats in the Great Basin of central Nevada. Geomorphic and biotic characterization of the wet meadow complexes demonstrates that most terminate downvalle...

  17. Fracturing and brecciation along the Max Meadows thrust, southwestern Virginia

    SciTech Connect

    Haneberg, W.C.

    1984-04-01

    Fracturing is an important mechanism of porosity development in deformed hydrocarbon provinces such as the Eastern Overthrust belt, but the sizes and shapes of fractured zones place critical constraints on exploration strategies. Fracturing and brecciation associated with the Max Meadows thrust, along which the Cambrian Rome Formation have been emplaced atop the younger Cambrian Elbrook and Conococheague Formations of the Pulaski thrust sheet, are controlled by lithology, proximity to the fault, and mesoscopic folding. Within the Max Meadows sheet, Rome carbonates are highly fractured and, in fold cores near the fault, brecciated. Rome mudstones and sandstones are tightly folded, and near the fault have developed both an incipient axial planar cleavage and a set of closely spaced fractures striking perpendicular to fold axes. In comparison, the wholly carbonate sequence of the Pulaski sheet had earlier been folded into a large syncline characterized by bedding-parallel shear in shaly and thin-bedded layers, flexural slip folding, and localized fracturing of thick layers. Thus breccia and fracture porosity zones in the study area are highly localized, of irregular geometry, and essentially restricted to the upper thrust sheet. Zones of tectonic breccia and fracture porosity are not attractive exploration targets, then, unless they occur as uniform and widespread broken zones in sedimentologically and mechanically homogeneous beds.

  18. Multiscale variability of amphipod assemblages in Posidonia oceanica meadows

    NASA Astrophysics Data System (ADS)

    Sturaro, Nicolas; Lepoint, Gilles; Vermeulen, Simon; Gobert, Sylvie

    2015-01-01

    The study of spatial patterns is important in understanding the causes of the distribution and abundance of organisms, and it also provides a valuable basis for management and conservation. Amphipod crustaceans are key organisms in seagrass ecosystems. However, little attention has been paid to the spatial scales at which amphipod assemblages may vary. We examined variability patterns of amphipod populations inhabiting Posidonia oceanica meadows, over spatial scales spanning four orders of magnitude (1 to 1000 meters) and for two consecutive years. This study reports the scales that contributed most to spatial variation of amphipod assemblages and explores the potential processes driving the observed patterns, with particular emphasis on habitat features. The number of species, the diversity, and the density of some species varied substantially across years. For most species the highest spatial variation in density and biomass occurred at small scales (1 and 10 meters). Based on density data, the structure of amphipod assemblages did not differ at any scales investigated. The patchiness that occurred at small scales may have been related to habitat features, but only weakly. Instead, we postulate that amphipod behavioral processes likely represent good explanatory factors. Although, small-scale spatial variability can be an important feature of amphipod assemblages in P. oceanica meadows, some patterns may have gone undetected because they occur at scales smaller than those investigated.

  19. Artificial Warming of Arctic Meadow under Pollution Stress: Experimental design

    NASA Astrophysics Data System (ADS)

    Moni, Christophe; Silvennoinen, Hanna; Fjelldal, Erling; Brenden, Marius; Kimball, Bruce; Rasse, Daniel

    2014-05-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, notably because future warming is expected to be disproportionate as compared to world averages. Likewise, greenhouse gas (GHG) release from terrestrial ecosystems exposed to climate warming is expected to be the largest in the arctic. Artic agriculture, in the form of cultivated grasslands, is a unique and economically relevant feature of Northern Norway (e.g. Finnmark Province). In Eastern Finnmark, these agro-ecosystems are under the additional stressor of heavy metal and sulfur pollution generated by metal smelters of NW Russia. Warming and its interaction with heavy metal dynamics will influence meadow productivity, species composition and GHG emissions, as mediated by responses of soil microbial communities. Adaptation and mitigation measurements will be needed. Biochar application, which immobilizes heavy metal, is a promising adaptation method to promote positive growth response in arctic meadows exposed to a warming climate. In the MeadoWarm project we conduct an ecosystem warming experiment combined to biochar adaptation treatments in the heavy-metal polluted meadows of Eastern Finnmark. In summary, the general objective of this study is twofold: 1) to determine the response of arctic agricultural ecosystems under environmental stress to increased temperatures, both in terms of plant growth, soil organisms and GHG emissions, and 2) to determine if biochar application can serve as a positive adaptation (plant growth) and mitigation (GHG emission) strategy for these ecosystems under warming conditions. Here, we present the experimental site and the designed open-field warming facility. The selected site is an arctic meadow located at the Svanhovd Research station less than 10km west from the Russian mining city of Nikel. A splitplot design with 5 replicates for each treatment is used to test the effect of biochar amendment and a 3oC warming on the Arctic meadow. Ten circular

  20. Effects of herbage removal on productivity of selected high-Sierra meadow community types

    USGS Publications Warehouse

    Stohlgren, Thomas J.; DeBenedetti, Steven H.; Parsons, David J.

    1989-01-01

    We investigated the effects of herbage removal on three subalpine meadow plant communities in the Rock Creek drainage of Sequoia National Park, California, USA. In the xeric Carex exserta Mkze. (short-hair sedge) type, annual aboveground productivity averaged 19 g/m2 in control plots (clipped once after plant senescence in late September) over a five-year period. Annual aboveground productivity was enhanced about 30%–35% when plots in this community type were clipped more frequently (i.e., “additional” herbage removal in the early, mid, and late seasons) during each of four treatment years but was reduced by 13%–19% during a fifth (recovery) year in which all but late September clipping was suspended. In a moderately mesic Eleocharis pauciflora (Lightf.) Link. (few-flowered spike rush)-Calamagrostis breweri Thurb. (short-hair grass) type, control plot productivity averaged 115 g/m2/yr and was reduced by 20–30% by the additional herbage removal. A more mesic Deschampsia caespitosa (L.) Beauv. (tufted hairgrass)-Carex rostrata Stokes, (beaked sedge) type had the greatest mean above-ground productivity (169 g/m2/yr) but also showed damage (i.e., decrease in productivity by 15%–20%) caused by the additional herbage removal. These data suggest that long-term, intensive herbage removal may be more detrimental to moderately mesic and mesic subalpine meadow community types than to xeric types.

  1. Supplement Analysis for the Watershed Management Program EIS, (DOE/EIS-0265/SA-99) - Longley Meadows Restoration Project

    SciTech Connect

    Keller, Carl J.

    2002-11-22

    The overall objective of the project is to restore as much as possible, the natural character and function of the Longley Meadows wetland complex. This project is a joint partnership among the CTUIR, Grand Rhonda Model Watershed Program, Oregon Department of Fish and Wildlife, Natural Resource Conservation Service, U.S. Department of Agriculture, and BPA. This project involves several separate components that are part of a regionwide effort to protect and restore anadromous fish habitat in the Grand Ronde Basin. The individual actions are as follows: construct a one-mile restoration channel at the lower reach of Bear Creek; divert Bear Creek into a restoration channel; reclaim an existing channelized stream reach; develop riparian conservation easements with private landowner along the Grande Ronde River, Bear Creek, and Jordan Creek and manage the properties for conservation purposes; construct riparian easement boundary fences; make instream placement of large woody debris; and plant trees and shrubs in the riparian zone. A more detailed description for each of these proposed activities is provided in the Biological Assessment for the Longley Meadow Restoration Project (Bear and Jordan Creeks) that was prepared in March 2002 by the Confederated Tribes of the Umatilla Indian Reservation.

  2. Seed rain and its relationship with above-ground vegetation of degraded Kobresia meadows.

    PubMed

    Shang, Zhan-Huan; Yang, Shi-Hai; Shi, Jian-Jun; Wang, Yan-Long; Long, Rui-Jun

    2013-01-01

    Seed rain is a crucial element in vegetation regeneration, but has been rarely studied in high altitude regions, particularly degraded Kobresia meadow. Weed infestation is a distinctive feature of pasture degradation in Kobresia meadows on the Tibetan plateau, the ecological mechanism of which is closely related with vegetation's seed rain. In this paper we assess the effect of vegetation degradation on seed rain and consider its implication for restoration of degraded Kobresia meadows in the headwater area of Yellow river, through analysis of seed species composition, number of seeds landing per m(2) of soil surface, and their relationship with above ground vegetation. Vegetation degradation had an impact on the species composition and numbers of seeds in seed rain and their relationship with above-ground vegetation. Within the un-degraded meadow, which provided a closed vegetation cover, 35 % of the seed rain was of sedge and gramineae species. However, within the degraded meadows, as the extent of degradation increased, so the total number of seeds m(-2) increased, with those derived from sedge and gramineae species forming a declining proportion of the total. Degradation of Kobresia meadow on the Tibetan plateau is exacerbated by the seed input of weed species (such as Oxytropis ochrocephala, Carum carvi, Aconitum pendulum, Pedicularis kansuensis in this study). Therefore, a major priority for the restoration of such degraded meadows should be the elimination of these weeds from the above ground vegetation by human intervention.

  3. Montane meadows in the Sierra Nevada: comparing terrestrial and aquatic assessment methods.

    PubMed

    Purdy, Sarah E; Moyle, Peter B; Tate, Kenneth W

    2012-11-01

    We surveyed montane meadows in the northern Sierra Nevada and southern Cascades for two field seasons to compare commonly used aquatic and terrestrial-based assessments of meadow condition. We surveyed (1) fish, (2) reptiles, (3) amphibians, (4) aquatic macroinvertebrates, (5) stream geomorphology, (6) physical habitat, and (7) terrestrial vegetation in 79 meadows between the elevations of 1,000 and 3,000 m. From the results of those surveys, we calculated five multi-metric indices based on methods commonly used by researchers and land management agencies. The five indices consisted of (1) fish only, (2) native fish and amphibians, (3) macroinvertebrates, (4) physical habitat, and (5) vegetation. We compared the results of the five indices and found that there were significant differences in the outcomes of the five indices. We found positive correlations between the vegetation index and the physical habitat index, the invertebrate index and the physical habitat index, and the two fish-based indices, but there were significant differences between indices in both range and means. We concluded that the five indices provided very different interpretations of the condition in a given meadow. While our assessment of meadow condition changed based on which index was used, each provided an assessment of different components important to the overall condition of a meadow system. Utilizing a multimetric approach that accounts for both terrestrial and aquatic habitats provides the best means to accurately assess meadow condition, particularly given the disproportionate importance of these systems in the Sierra Nevada landscape. PMID:22183163

  4. Does Causation Matter? Post-disturbance Response of Incised Montane Meadow Streams to Restoration.

    NASA Astrophysics Data System (ADS)

    Natali, J.

    2014-12-01

    Land use disturbance from grazing, timber harvest, and transportation infrastructure has been implicated in stream incision within groundwater-dependent montane meadow ecosystems, particularly in the Sierra Nevada of California. Restoration approaches, such as the widely-used "Plug-and-Pond" technique, attempt to restore groundwater levels in incised meadows by introducing shallow, meandering channel morphologies that support more frequent overbank flows and prevent meadow dewatering via seepage to stream networks. Systematic field surveys of over ten "Plug-and-Pond" projects built at least eight years ago and distributed across the Sierra Nevada indicate that pre- and post-restoration basin-scale and meadow-scale sediment transport strongly influence restoration outcomes. The scale of anthropogenic disturbance, along with abiotic factors such as climatic gradients and meadow-scale soil characteristics, influence the resilience of restored meadow systems. Based on these observations and analyses, a conceptual model of meadow ecosystem vulnerability to disturbance and potential for restoration prominently features multi-scaled geomorphic feedbacks that incorporate the influence of geology, climate, vegetation, and hydrology.

  5. Rapid-infiltration research at Flushing Meadows Project, Arizona

    SciTech Connect

    Bouwer, H.; Rice, R.C.; Lance, J.C.; Gilbert, R.G.

    1980-10-01

    The Flushing Meadows Project in Arizona was initiated to investigate the feasibility of using wastewater for irrigation and the effects of infiltration on water quality. The results of the second phase of this 10 yr study, focusing on maximization of nitrogen removal and reduction of hydraulic loading, are discussed. Infiltration rates employed in this phase were 0.3-1 m/d, using a water depth of 0.3 m in the six experimental water basins. Removal of dissolved and suspended solids, nitrogen, phosphorus, organic carbon, and pathogens was monitored. Phosphate removal increased with increasing distance of wastewater movement; 65% of the total nitrogen content was removed. (3 graphs, 1 map, 23 references, 3 tables)

  6. Food supply depends on seagrass meadows in the coral triangle

    NASA Astrophysics Data System (ADS)

    Unsworth, Richard K. F.; Hinder, Stephanie L.; Bodger, Owen G.; Cullen-Unsworth, Leanne C.

    2014-09-01

    The tropical seascape provides food and livelihoods to hundreds of millions of people, but the support of key habitats to this supply remains ill appreciated. For fisheries and conservation management actions to help promote resilient ecosystems, sustainable livelihoods, and food supply, knowledge is required about the habitats that help support fisheries productivity and the consequences of this for food security. This paper provides an interdisciplinary case study from the coral triangle of how seagrass meadows provide support for fisheries and local food security. We apply a triangulated approach that utilizes ecological, fisheries and market data combined with over 250 household interviews. Our research demonstrates that seagrass associated fauna in a coral triangle marine protected area support local food supply contributing at least 50% of the fish based food. This formed between 54% and 99% of daily protein intake in the area. Fishery catch was found to significantly vary with respect to village (p < 0.01) with habitat configuration a probable driver. Juvenile fish comprised 26% of the fishery catch and gear type significantly influenced this proportion (<0.05). Limited sustainability of fishery practices (high juvenile catch and a 51% decline in CPUE for the biggest fishery) and poor habitat management mean the security of this food supply has the potential to be undermined in the long-term. Findings of this study have implications for the management and assessment of fisheries throughout the tropical seascape. Our study provides an exemplar for why natural resource management should move beyond biodiversity and consider how conservation and local food security are interlinked processes that are not mutually exclusive. Seagrass meadows are under sustained threat worldwide, this study provides evidence of the need to conserve these not just to protect biodiversity but to protect food security.

  7. Methane and nitrous oxide exchange over a managed hay meadow

    NASA Astrophysics Data System (ADS)

    Hörtnagl, L.; Wohlfahrt, G.

    2014-12-01

    The methane (CH4) and nitrous oxide (N2O) exchange of a temperate mountain grassland near Neustift, Austria, was measured during 2010-2012 over a time period of 22 months using the eddy covariance method. Exchange rates of both compounds at the site were low, with 97% of all half-hourly CH4 and N2O fluxes ranging between ±200 and ±50 ng m-2 s-1, respectively. The meadow acted as a sink for both compounds during certain time periods, but was a clear source of CH4 and N2O on an annual timescale. Therefore, both gases contributed to an increase of the global warming potential (GWP), effectively reducing the sink strength in terms of CO2 equivalents of the investigated grassland site. In 2011, our best guess estimate showed a net greenhouse gas (GHG) sink of -32 g CO2 equ. m-2 yr-1 for the meadow, whereby 55% of the CO2 sink strength of -71 g CO2 m-2 yr-1 was offset by CH4 (N2O) emissions of 7 (32) g CO2 equ. m-2 yr-1. When all data were pooled, the ancillary parameters explained 27 (42)% of observed CH4 (N2O) flux variability, and up to 62 (76)% on shorter timescales in-between management dates. In the case of N2O fluxes, we found the highest emissions at intermediate soil water contents and at soil temperatures close to 0 or above 14 °C. In comparison to CO2, H2O and energy fluxes, the interpretation of CH4 and N2O exchange was challenging due to footprint heterogeneity regarding their sources and sinks, uncertainties regarding post-processing and quality control. Our results emphasize that CH4 and N2O fluxes over supposedly well-aerated and moderately fertilized soils cannot be neglected when evaluating the GHG impact of temperate managed grasslands.

  8. The large penumbra: long-distance effects of artificial beach nourishment on Posidonia oceanica meadows.

    PubMed

    Manzanera, Marta; Alcoverro, Teresa; Jiménez, José A; Romero, Javier

    2014-09-15

    We used modelling and field approaches to assess the influence of beach nourishment on a relatively distant Posidonia oceanica seagrass meadow in the NW Mediterranean. Both sediment transport models and in situ observations showed that, two years after the nourishment and under wave climates prevalent during the study period, sediment movement was restricted to shallow waters (<7 m), above meadow shallow limit. The only significant impact on seagrass meadows during this period was an increase in fine sediments, associated with vertical rhizome growth rates 1.5-1.7 times higher than normal. However, running the model with data of wave climate over several decades indicates that strong storms able to transfer these sediments much deeper, potentially burying meadows, occur with a return period of about 25 years. Taken together, our results suggest that beach nourishment could result in significant sub-lethal and lethal consequences for seagrasses that may go unnoticed with short-term evaluations.

  9. Seagrass meadows globally as a coupled social-ecological system: implications for human wellbeing.

    PubMed

    Cullen-Unsworth, Leanne C; Nordlund, Lina Mtwana; Paddock, Jessica; Baker, Susan; McKenzie, Len J; Unsworth, Richard K F

    2014-06-30

    Seagrass ecosystems are diminishing worldwide and repeated studies confirm a lack of appreciation for the value of these systems. In order to highlight their value we provide the first discussion of seagrass meadows as a coupled social-ecological system on a global scale. We consider the impact of a declining resource on people, including those for whom seagrass meadows are utilised for income generation and a source of food security through fisheries support. Case studies from across the globe are used to demonstrate the intricate relationship between seagrass meadows and people that highlight the multi-functional role of seagrasses in human wellbeing. While each case underscores unique issues, these examples simultaneously reveal social-ecological coupling that transcends cultural and geographical boundaries. We conclude that understanding seagrass meadows as a coupled social-ecological system is crucial in carving pathways for social and ecological resilience in light of current patterns of local to global environmental change.

  10. RELATIONSHIPS AMONG GEOMORPHOLOGY, HYDROLOGY, AND VEGETATION IN RIPARIAN MEADOWS: RESTORATION IMPLICATIONS

    EPA Science Inventory

    Vegetation patterns and dynamics within riparian corridors are controlled largely by geomorphic position, substrate characteristics and hydrologic regimes. Understanding management and restoration options for riparian meadow complexes exhibiting stream incision requires knowledge...

  11. HYDROLOGY OF CENTRAL GREAT BASIN MEADOW ECOSYSTEMS – EFFECTS OF STREAM INCISION

    EPA Science Inventory

    Riparian wet meadow complexes in the mountains of the central Great Basin are scarce, ecologically important systems that are threatened by stream incision. Our interdisciplinary group has investigated 1) the interrelationships of geomorphology, hydrology, and vegetation; and 2) ...

  12. Modelling reference conditions for the upper limit of Posidonia oceanica meadows: a morphodynamic approach

    NASA Astrophysics Data System (ADS)

    Vacchi, Matteo; Misson, Gloria; Montefalcone, Monica; Archetti, Renata; Nike Bianchi, Carlo; Ferrari, Marco

    2014-05-01

    The upper portion of the meadows of the protected Mediterranean seagrass Posidonia oceanica occurs in the region of the seafloor mostly affected by surf-related effects. Evaluation of its status is part of monitoring programs, but proper conclusions are difficult to draw due to the lack of definite reference conditions. Comparing the position of the meadow upper limit with the beach morphodynamics (i.e. the distinctive type of beach produced by topography and wave climate) provided evidence that the natural landwards extension of meadows can be predicted. Here we present an innovative predictive cartographic approach able to identify the seafloor portion where the meadow upper limit should naturally lies (i.e. its reference conditions). The conceptual framework of this model is based on 3 essential components: i) Definition of the breaking depth geometry: the breaking limit represents the major constrain for the landward meadow development. We modelled the breaking limit (1 year return time) using the software Mike 21 sw. ii) Definition of the morphodynamic domain of the beach using the surf scaling index ɛ; iii) Definition of the P. oceanica upper limit geometry. We coupled detailed aerial photo with thematic bionomic cartography. In GIS environment, we modelled the seafloor extent where the meadow should naturally lies according to the breaking limit position and the morphodynamic domain of the beach. Then, we added the GIS layer with the meadow upper limit geometry. Therefore, the final output shows, on the same map, both the reference condition and the actual location of the upper limit. It make possible to assess the status of the landward extent of a given P. oceanica meadow and quantify any suspected or observed regression caused by anthropic factors. The model was elaborated and validated along the Ligurian coastline (NW Mediteraanean) and was positively tested in other Mediterranean areas.

  13. The impact of dredge-fill on Posidonia oceanica seagrass meadows: regression and patterns of recovery.

    PubMed

    Badalamenti, Fabio; Alagna, Adriana; D'Anna, Giovanni; Terlizzi, Antonio; Di Carlo, Giuseppe

    2011-03-01

    Posidonia oceanica meadows can be severely damaged by dredge-fill operations. We report on the construction of gas pipelines that occurred between 1981 and 1993 in SW Sicily, Italy. A large portion of the meadow was mechanically removed, and the excavated trench was filled with a mosaic of substrates, ranging from sand to consolidated rock debris. Meadow loss and recovery were quantified over 7 years after the end of operations. We recorded an overall loss of 81.20 ha of meadow. Substrate strongly affected recovery as the percent cover by P. oceanica consistently increased on calcareous rubble, reaching values of 44.37 ± 3.05% in shallow sites after 7 years, whereas no significant increase occurred on other substrates. As in the Mediterranean Sea exploitation of coastal areas continues to grow with consequent impacts on P. oceanica meadows, this case study illustrates how artificial rubble-like materials could be employed to support the restoration of damaged meadows. PMID:21256527

  14. Estimating Carbon Storage in Eelgrass Meadows in the Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Simpson, J.; McDowell, B.; Sacarny, M.; Colarusso, P.

    2014-12-01

    Seagrass meadows can be hotspots for carbon storage and sequestration, but the data currently available shows an enormous amount of variability. Carbon storage varies with seagrass species and region, and with meadow condition, where healthy meadows sequester carbon but those that are declining may be sources of inorganic carbon to the atmosphere. Very little is known about carbon storage in Zostera marina (eelgrass) meadows in the Gulf of Maine, where they are threatened by poor water quality and physical disturbance. In 2014 we studied two eelgrass meadows in coastal Massachusetts, U.S.A. We sampled biomass and measured carbon content in above- and below-ground plant tissues, sediments, and particulate organic matter in the water column. We estimated bed density and extent using a combination of sonar, visual imaging, and diver surveys. To investigate persistence of carbon storage in sediments, we also sampled sediments from an area where a meadow had historically existed, but had died back in 2012. Results of this work will not only support eelgrass restoration and protection measures locally, but will also help clarify our global understanding of carbon storage in blue habitats.

  15. Carbon distribution in subalpine forests and meadows of the Olympic Mountains, Washington

    USGS Publications Warehouse

    Prichard, S.J.; Peterson, D.L.; Hammer, R.D.

    2000-01-01

    Estimates of C storage in mountainous regions are rare. Foresta??meadow ecotones in subalpine ecosystems, which contain a mosaic of forests and meadows, may be particularly sensitive to future changes in climate and are therefore important to include in estimates of terrestrial C storage. In this study, we quantified soil C and ecosystem C pools in subalpine forest and meadow soils of the northeastern (NE, dry climate) and southwestern (SW, wet climate) Olympic Mountains. Carbon concentrations of mineral soil are relatively high in upper horizons, ranging from 43 to 142 g kg-1 in NE soils and 27 to 162 g kg-1 in SW soils. Northeastern meadow soils store more C than NE forests , while SW forest soils store more C than SW meadows . Ecosystem C storage is greater in forests than in meadows. Under a warmer climatic scenario with drier summers and wetter winters, subalpine C storage may decrease in the NE and increase in the SW, and changes in C storage will be closely related to vegetation distribution, ecosystem productivity, decomposition rates, and local disturbance regimes. Because ecosystem processes and associated C storage differ between high- and low-elevation ecosystems, it is important that data from both high- and low-elevation sites are included in estimates of C storage in terrestrial ecosystems.

  16. Soil microclimate monitoring in forested and meadow sites

    NASA Astrophysics Data System (ADS)

    Freyerova, Katerina; Safanda, Jan

    2016-04-01

    It is well known fact that forest microclimate differs from open area microclimate (Geiger 1965). Less attention is paid to soil temperatures and their long-term monitoring. To evaluate and compare these two environments from the soil microclimate point of view, Institute of Geophysics in Prague monitors soil and air temperatures in Bedřichov in the Jizerské Hory Mountains (Czech Republic). The soil temperatures are measured in three depths (20, 50 and 100 cm) in forest (700 m a. s. l.) and meadow (750 m a. s. l.). Air temperatures are measured at 2m height both in forest and meadow. Nowadays, we have more than three years long time series. The most of studies and experiments described in literature are short-term ones (in order of days or weeks). However, from short-term experiments the seasonal behaviour and trends can be hardly identified and conclusions on soil temperature reaction to climatic extremes such as heat waves, drought or freeze cannot be done with confidence. These drawbacks of the short-term experiments are discussed in literature (eg. Morecroft et al. 1998; Renaud et al. 2011). At the same, with progression of the global warming, the expected increasing frequency of climatic extremes will affect the future form of forest vegetation (Von Arx et al. 2012). The soil and air temperature series, both from the forest and meadow sites, are evaluated and interpreted with respect to long term temperature characteristics and seasonal trends. The emphasis is given on the soil temperature responses to extreme climatic situations. We examine variability between the localities and depths and spatial and temporal changes in this variability. This long-term monitoring allows us to better understand and examine the behaviour of the soil temperature in extreme weather situations. Therefore, we hope to contribute to better prediction of future reactions of this specific environments to the climate change. Literature Geiger, R., 1965. The climate near the ground

  17. Soil microclimate monitoring in forested and meadow sites

    NASA Astrophysics Data System (ADS)

    Freyerova, Katerina; Safanda, Jan

    2016-04-01

    It is well known fact that forest microclimate differs from open area microclimate (Geiger 1965). Less attention is paid to soil temperatures and their long-term monitoring. To evaluate and compare these two environments from the soil microclimate point of view, Institute of Geophysics in Prague monitors soil and air temperatures in Bedřichov in the Jizerské Hory Mountains (Czech Republic). The soil temperatures are measured in three depths (20, 50 and 100 cm) in forest (700 m a. s. l.) and meadow (750 m a. s. l.). Air temperatures are measured at 2m height both in forest and meadow. Nowadays, we have more than three years long time series. The most of studies and experiments described in literature are short-term ones (in order of days or weeks). However, from short-term experiments the seasonal behaviour and trends can be hardly identified and conclusions on soil temperature reaction to climatic extremes such as heat waves, drought or freeze cannot be done with confidence. These drawbacks of the short-term experiments are discussed in literature (eg. Morecroft et al. 1998; Renaud et al. 2011). At the same, with progression of the global warming, the expected increasing frequency of climatic extremes will affect the future form of forest vegetation (Von Arx et al. 2012). The soil and air temperature series, both from the forest and meadow sites, are evaluated and interpreted with respect to long term temperature characteristics and seasonal trends. The emphasis is given on the soil temperature responses to extreme climatic situations. We examine variability between the localities and depths and spatial and temporal changes in this variability. This long-term monitoring allows us to better understand and examine the behaviour of the soil temperature in extreme weather situations. Therefore, we hope to contribute to better prediction of future reactions of this specific environments to the climate change. Literature Geiger, R., 1965. The climate near the ground

  18. Methane and nitrous oxide exchange over a managed hay meadow

    PubMed Central

    Hörtnagl, L.; Wohlfahrt, G.

    2015-01-01

    The methane (CH4) and nitrous oxide (N2O) exchange of a temperate mountain grassland near Neustift, Austria, was measured during 2010–2012 over a time period of 22 months using the eddy covariance method. Exchange rates of both compounds at the site were low, with 97% of all half-hourly CH4 and N2O fluxes ranging between ±200 and ±50 ng m−2 s−1, respectively. The meadow acted as a sink for both compounds during certain time periods, but was a clear source of CH4 and N2O on an annual timescale. Therefore, both gases contributed to an increase of the global warming potential (GWP), effectively reducing the sink strength in terms of CO2 equivalents of the investigated grassland site. In 2011, our best guess estimate showed a net greenhouse gas (GHG) sink of −32 g CO2 equ. m−2 yr−1 for the meadow, whereby 55% of the CO2 sink strength of −71 g CO2m−2 yr−1 was offset by CH4 (N2O) emissions of 7 (32) g CO2 equ. m−2 yr−1. When all data were pooled, the ancillary parameters explained 27 (42)% of observed CH4 (N2O) flux variability, and up to 62 (76)% on shorter timescales in-between management dates. In the case of N2O fluxes, we found the highest emissions at intermediate soil water contents and at soil temperatures close to 0 or above 14 °C. In comparison to CO2, H2O and energy fluxes, the interpretation of CH4 and N2O exchange was challenging due to footprint heterogeneity regarding their sources and sinks, uncertainties regarding post-processing and quality control. Our results emphasize that CH4 and N2O fluxes over supposedly well-aerated and moderately fertilized soils cannot be neglected when evaluating the GHG impact of temperate managed grasslands. PMID:25821473

  19. Methane and nitrous oxide exchange over a managed hay meadow

    NASA Astrophysics Data System (ADS)

    Hörtnagl, L.; Wohlfahrt, G.

    2014-06-01

    The methane (CH4) and nitrous oxide (N2O) exchange of a temperate mountain grassland near Neustift, Austria, was measured during 2010-2012 over a time period of 22 months using the eddy covariance method. Exchange rates of both compounds at the site were low, with more than 95% of the half-hourly fluxes of CH4 and N2O ranging between ±10 and ±1 nmol m-2 s-1, respectively. The meadow acted as a sink for both compounds during certain time periods, but was a clear source of CH4 and N2O on an annual time scale. Therefore, both gases contributed to an increase of the global warming potential (GWP), effectively reducing the sink strength in terms of CO2-equivalents of the investigated grassland site. In 2011, our best guess estimate showed a net GHG sink of -32 g CO2-equ. m-2 yr-1 for the meadow, whereby 55% of the CO2 sink strength of -71 g CO2 m-2 yr-1 was offset by CH4/N2O emissions of 7/32 g CO2-equ. m-2 yr-1. When all data were pooled, the ancillary parameters explained 26/38% of observed CH4/N2O flux variability, and up to 62/75% on shorter time scales in-between management dates. In case of N2O fluxes, we found highest emissions at intermediate soil water contents and at soil temperatures close to zero or above 14 °C. In comparison to CO2, H2O and energy fluxes, the interpretation of CH4 and N2O exchange was challenging due to footprint heterogeneity regarding their sources and sinks, uncertainties regarding post-processing and quality control. Our results emphasize that CH4 and N2O fluxes over supposedly well-aerated and moderately fertilized soils cannot be neglected when evaluating the GHG impact of temperate managed grasslands.

  20. Interaction diversity within quantified insect food webs in restored and adjacent intensively managed meadows.

    PubMed

    Albrecht, Matthias; Duelli, Peter; Schmid, Bernhard; Müller, Christine B

    2007-09-01

    1. We studied the community and food-web structure of trap-nesting insects in restored meadows and at increasing distances within intensively managed grassland at 13 sites in Switzerland to test if declining species diversity correlates with declining interaction diversity and changes in food-web structure. 2. We analysed 49 quantitative food webs consisting of a total of 1382 trophic interactions involving 39 host/prey insect species and 14 parasitoid/predator insect species. Species richness and abundance of three functional groups, bees and wasps as the lower trophic level and natural enemies as the higher trophic level, were significantly higher in restored than in adjacent intensively managed meadows. Diversity and abundance of specific trophic interactions also declined from restored to intensively managed meadows. 3. The proportion of attacked brood cells and the mortality of bees and wasps due to natural enemies were significantly higher in restored than in intensively managed meadows. Bee abundance and the rate of attacked brood cells of bees declined with increasing distance from restored meadows. These findings indicate that interaction diversity declines more rapidly than species diversity in our study system. 4. Quantitative measures of food-web structure (linkage density, interaction diversity, interaction evenness and compartment diversity) were higher in restored than in intensively managed meadows. This was reflected in a higher mean number of host/prey species per consumer species (degree of generalism) in restored than in intensively managed meadows. 5. The higher insect species and interaction diversity was related to higher plant species richness in restored than in intensively managed meadows. In particular, bees and natural enemies reacted positively to increased plant diversity. 6. Our findings provide empirical evidence for the theoretical prediction that decreasing species richness at lower trophic levels should reduce species richness at

  1. Carbon monoxide exchange and partitioning of a managed mountain meadow

    NASA Astrophysics Data System (ADS)

    Wohlfahrt, G.; Hammerle, A.; Kitz, F.; Spielmann, F.

    2015-12-01

    With an average mole fraction of 100 ppb carbon monoxide (CO) plays a critical role in atmospheric chemistry and thus has an indirect global warming potential. While sources/sinks of CO on land at least partially cancel out each other, the magnitude of CO sources and sinks is highly uncertain. Even if direct CO fluxes from/to land ecosystems are very much likely clearly lower in magnitude compared to anthropogenic emissions, biomass burning, emissions from chemical precursors and the OH sink, it may be premature to neglect any direct contributions of land ecosystems to the CO budget. In addition, changes in global climate and resulting changes in global productivity may require re-evaluating older data and assumptions. One major reason for the large uncertainty is a general scarcity of empirical data. An additional factor contributing to the uncertainty is the lack of ecosystem-scale CO exchange measurements, i.e. CO flux data that encompass all sources and sinks within an ecosystem. Here we present data on continuous eddy covariance measurements of CO-fluxes above a managed mountain grassland in combination with soil chamber flux measurements, within- and above-canopy concentration profiles and an inverse Lagrangian analysis to disentangle sinks and sources of CO. Preliminary results show the grassland ecosystem to be a net source for CO during daytime, with increasing flux rates at higher solar radiation. At night, if at all, the meadow is a slight sink for CO. The same holds true for soil flux measurements.

  2. Melatonin influences sex-specific prenatal mortality in meadow voles.

    PubMed

    Gorman, M R; Ferkin, M H; Dark, J

    1994-11-01

    Meadow voles exhibit seasonal changes in litter size, ovulation rates, and prenatal mortality. To investigate the proximate bases of seasonal changes in reproductive effort, adult female voles, maintained in long photoperiods (14 h of light/day), were injected daily with 10 micrograms melatonin 2 h before light offset to extend the duration of the nighttime melatonin pulse. At parturition the number, sex, and weight of offspring were assessed. The number of ovarian corpora lutea (CL), an index of potential litter size, was used to calculate rates of prenatal survival (i.e., pups per CL). Prenatal survival rates were reduced in female but not male pups of dams that had been injected before blastocyst implantation (Days 1-6 of pregnancy) with melatonin as compared with saline. Melatonin injections initiated after blastocyst implantation (Days 7-21 of pregnancy) did not affect prenatal survival, nor were birth weights of pups affected by either pre- or postimplantation melatonin treatment. We conclude that sex-specific prenatal survival is a labile feature of vole reproduction that may be under proximate control of photoperiod and melatonin before blastocyst implantation. PMID:7849189

  3. Long day lengths promote brain growth in meadow voles.

    PubMed

    Dark, J; Spears, N; Whaling, C S; Wade, G N; Meyer, J S; Zucker, I

    1990-05-01

    Male meadow voles kept in a long photoperiod (LP) from birth to 70 days of age have heavier brains than those kept in a short photoperiod (SP). Brain weights of male voles kept in the LP first exceeded those of SP animals at 20 days of age; differences were greatest at 35 days (5.8%) and persisted through 140 days of age (2%), although the magnitude of the difference declined progressively. Accelerated compensatory increases in brain weight were observed in voles transferred from the SP to the LP at 70 days of age. Total brain DNA content, an index of cell number, was not significantly affected by initial or final photoperiod, although it increased 7.8% within 70 days after voles were transferred from the SP to the LP. Brain weights (but not DNA content) of males exceeded those of females, but this sex difference was present only in the LP. We suggest that short day lengths retard brain development by reducing rates of myelination and possibly reducing cell size as well; this is part of a general retardation of somatic growth associated with a delayed onset of puberty that can be reversed by a stimulatory LP but, ordinarily, occurs spontaneously as voles become refractory to short day lengths. PMID:2192819

  4. Patterns and Drivers of Scattered Tree Loss in Agricultural Landscapes: Orchard Meadows in Germany (1968-2009)

    PubMed Central

    Plieninger, Tobias; Levers, Christian; Mantel, Martin; Costa, Augusta; Schaich, Harald; Kuemmerle, Tobias

    2015-01-01

    Scattered trees support high levels of farmland biodiversity and ecosystem services in agricultural landscapes, but they are threatened by agricultural intensification, urbanization, and land abandonment. This study aimed to map and quantify the decline of orchard meadows (scattered fruit trees of high nature conservation value) for a region in Southwestern Germany for the 1968 2009 period and to identify the driving forces of this decline. We derived orchard meadow loss from 1968 and 2009 aerial images and used a boosted regression trees modelling framework to assess the relative importance of 18 environmental, demographic, and socio-economic variables to test five alternative hypothesis explaining orchard meadow loss. We found that orchard meadow loss occurred in flatter areas, in areas where smaller plot sizes and fragmented orchard meadows prevailed, and in areas near settlements and infrastructure. The analysis did not confirm that orchard meadow loss was higher in areas where agricultural intensification was stronger and in areas of lower implementation levels of conservation policies. Our results demonstrated that the influential drivers of orchard meadow loss were those that reduce economic profitability and increase opportunity costs for orchards, providing incentives for converting orchard meadows to other, more profitable land uses. These insights could be taken up by local- and regional-level conservation policies to identify the sites of persistent orchard meadows in agricultural landscapes that would be prioritized in conservation efforts. PMID:25932914

  5. [Influences of land using patterns on the anti-wind erosion of meadow grassland].

    PubMed

    Zhou, Yao-Zhi; Wang-Xu; Yang, Gui-Xia; Xin, Xiao-Ping

    2008-05-01

    In order to analyse the effects of the human disturbances to the ability of anti-wind erosion of the Hulunbuir meadow grassland, the methods of vegetation investigation and the wind tunnel experiment were made to research the changes of vegetation and the abilities of anti-wind erosion of meadow grassland under different using patterns of meadow grassland. The results indicate that, under different grazing intensities of meadow grassland, the critical wind velocity of soil erosion (v) changes with the vegetation cover according to the relation of second power function. Along with the grazing intensities increasing and the vegetation cover reducing, the velocity of soil erosion rapidly increased on the condition of similar wind velocity which is speedier than the critical wind velocity of soil erosion. When the meadow grassland is mildly grazed which the vegetation cover maintains 63%, the velocity of soil erosion is small even there is gale that the wind velocity reach 25 m/s. When the vegetation cover of meadow grassland reduced to less than 35%, the velocity of soil erosion rapidly increased with the vegetation cover's reducing on the condition of the wind velocity is among 20-25 m/s. And owing to the no-tillage cropland of meadow grassland is completely far from the protection of the vegetation, the soil wind erosion quantity achieves 682.1 kg/hm2 in a minute when the wind velocity is 25 m/s, which approaches the average formation quantity of soil (1 000 kg/hm2) in a year.

  6. Modeling Alpine Meadow Restoration Techniques and their Effects on Stream Stage Regimes

    NASA Astrophysics Data System (ADS)

    Moore, C. E.; Lundquist, J. D.; Loheide, S. P.

    2010-12-01

    Meadow ecosystems in the Sierra Nevada of California often suffer from negative anthropogenic impacts, resulting in stream incision and meadow aridification. Groundwater dependent ecosystems, such as meadows, are especially vulnerable to channel degradation because alteration of stream stage propagates through the groundwater system to affect riparian vegetation. Restoration aimed at raising water table elevation of degraded meadow systems is becoming a salient and viable option as managers recognize the importance of intact headwaters. Stream stage controls groundwater levels and thus, vegetation communities, more dramatically than stream discharge in groundwater dependent ecosystems. Here we use a one dimensional hydraulic model, Hydraulic Engineering Center - River Analysis System (HEC-RAS) to model stream stage along the Tuolumne River, given a time series of stream discharge. Extensive hydroclimatic monitoring since 2001, and groundwater monitoring since 2006, make Tuolumne Meadows, in Yosemite National Park, California a prime location for a validated case study, applicable to other snow dominated basins. In order to determine the most plausible, efficient and effective strategy of restoring impacted meadows, different management scenarios are modeled. HEC-RAS modeling provides critical stream stage boundary conditions for groundwater modeling. Scenarios are chosen that are most effective at increasing stream stage and therefore water table levels. The effectiveness is quantified by modeling how each scenario changes the rating curve for a particular channel. Additionally, surface stage modeling allows decision makers to see under what flow conditions and what time period of the hydrograph is affected by restoration. Quantification of stream stage alterations is key for understanding restoration impacts during the short growing season in alpine meadows. Results of HEC-RAS modeling at Tuolumne Meadows are presented in the following formats to highlight the

  7. Wet meadow ecosystems contribute the majority of overwinter soil respiration from snow-scoured alpine tundra

    NASA Astrophysics Data System (ADS)

    Knowles, John F.; Blanken, Peter D.; Williams, Mark W.

    2016-04-01

    We measured soil respiration across a soil moisture gradient ranging from dry to wet snow-scoured alpine tundra soils throughout three winters and two summers. In the absence of snow accumulation, soil moisture variability was principally determined by the combination of mesotopographical hydrological focusing and shallow subsurface permeability, which resulted in a patchwork of comingled ecosystem types along a single alpine ridge. To constrain the subsequent carbon cycling variability, we compared three measures of effective diffusivity and three methods to calculate gradient method soil respiration from four typical vegetation communities. Overwinter soil respiration was primarily restricted to wet meadow locations, and a conservative estimate of the rate of overwinter soil respiration from snow-scoured wet meadow tundra was 69-90% of the maximum carbon dioxide (CO2) respired by seasonally snow-covered soils within this same catchment. This was attributed to higher overwinter soil temperatures at wet meadow locations relative to fellfield, dry meadow, and moist meadow communities, which supported liquid water and heterotrophic respiration throughout the winter. These results were corroborated by eddy covariance-based measurements that demonstrated an average of 272 g C m-2 overwinter carbon loss during the study period. As a result, we updated a conceptual model of soil respiration versus snow cover to express the potential for soil respiration variability from snow-scoured alpine tundra.

  8. Field observations of wave-induced streaming through a submerged seagrass (Posidonia oceanica) meadow

    NASA Astrophysics Data System (ADS)

    Luhar, Mitul; Infantes, Eduardo; Orfila, Alejandro; Terrados, Jorge; Nepf, Heidi M.

    2013-04-01

    paper reports the findings of a 2 week field campaign designed to study wave-induced flows within a meadow of Posidonia oceanica at water depth 9 m. Previous laboratory experiments suggest that waves induce a mean mass drift in the direction of wave propagation ("streaming") through submerged canopies of vegetation. This paper provides the first field measurements of this wave-induced streaming. During periods of high wave activity, streaming flows with magnitudes as high as 20% of the near-bed oscillatory velocity were measured within the meadow. In addition to presenting field measurements of wave-induced streaming, this paper also considers the damping of wave-induced oscillatory flow within the seagrass meadow. Oscillatory velocities measured within the meadow were reduced by less than 30% relative to those above the meadow over the duration of the study. This is in agreement with previous laboratory and field measurements which show that oscillatory flows are damped less within submerged canopies compared to unidirectional flows. Existing analytical models underpredict the magnitude of the streaming flow and overpredict oscillatory velocity reductions. These discrepancies are thought to arise because the drag generated by flexible seagrasses moving with wave-induced flow is not well described.

  9. Dynamic of Posidonia oceanica seagrass meadows in the northwestern Mediterranean: Could climate change be to blame?

    PubMed

    Pergent, Gérard; Pergent-Martini, Christine; Bein, Aymeric; Dedeken, Marine; Oberti, Pascal; Orsini, Antoine; Santucci, Jean-François; Short, Frederic

    2015-07-01

    The distribution and the vitality of the P. oceanica meadow were monitored in the western Mediterranean at 15 sites along the coasts of Corsica (1000 km of coastline) using two monitoring systems, the Posidonia Monitoring Network and SeagrassNet, between 2004 and 2013. While the vitality of the meadow is satisfactory overall, due to the low impact of human pressure along these coasts, patterns of change over time show a slight degradation of the main descriptors of the meadow. The meadow's vitality index had declined on average by 8.6%, the BiPo index by 9.8%, and there was a regression of the lower limit at six sites. While this pattern of change may reflect local alterations in the environment (increase or decline in human pressure), the regressive dynamic of the meadow observed at the lower limit at several reference sites (e.g., Marine Protected Areas, sites distant from sources of human impact) is more worrying. Two hypotheses might explain the regression observed: (i) the rise in mean sea level during the study period, which may have resulted in a significant regression in sectors where the slope is relatively slight, and (ii) the North Atlantic Oscillation (NAO), which declined from 2002 to reach very low values in 2010.

  10. Application of near surface geophysical methods to image water table response in an Alpine Meadow, Northern California.

    NASA Astrophysics Data System (ADS)

    Ayers, M.; Blacic, T. M.; Craig, M. S.; Yarnell, S. M.

    2015-12-01

    Meadows are recognized for their value to the ecological, hydrologic, and aesthetic functions of a watershed. As natural water retention sinks, meadows attenuate floods, improve water quality and support herbaceous vegetation that stabilize streambanks and promote high biodiversity. Alpine meadows are especially vital, serving as freshwater sources and distributing to lower lying provinces through ground and surface water interaction. These complexes are highly vulnerable to drought conditions, altered seasonal precipitation patterns, and mismanaged land use. One such location, Van Norden meadow located in the Donner Summit area west of Lake Tahoe, is one of the largest sub-alpine meadows in the Sierra Nevada mountain range of Northern California. Van Norden meadow offers a natural hydrologic laboratory. Ownership transfer of the area from a local land trust to the Forestry Service requires restoration toward natural meadow conditions, and involves notching the dam in 2016 to reduce currently impounded water volumes from 250 to less than 50 acre-feet. To monitor the effects of notching the dam on the upstream meadow conditions, better understanding of the surface and groundwater hydrology both pre-and post-base level alteration is required. Comprehensive understanding of groundwater flux that supports meadow reaches relies on knowledge of their often complex stratigraphic and structural subsurface framework. In recent years hydrogeophysics has emphasized the combination of near surface geophysical techniques, collaborated with well and borehole measures, to qualitatively define these parameters. Building on a preliminary GPR investigation conducted in 2014, in which 44 270 MHz transect lines were collected, we returned to Van Norden meadow in late summer 2015 to collect lower frequency GPR (50 and 100 MHz) and electrical resistivity profiles to better define the groundwater table, sedimentary, and structural features of the meadow.

  11. Carbon monoxide exchange and partitioning of a managed mountain meadow

    NASA Astrophysics Data System (ADS)

    Hammerle, Albin; Kitz, Florian; Spielmann, Felix; Gerdel, Katharina; Wohlfahrt, Georg

    2016-04-01

    With an average mole fraction of 100 ppb carbon monoxide (CO) plays a critical role in atmospheric chemistry and thus has an indirect global warming potential. While sources/sinks of CO on land at least partially cancel out each other, the magnitude of CO sources and sinks is highly uncertain. Even if direct CO fluxes from/to land ecosystems are very much likely clearly lower in magnitude compared to anthropogenic emissions, biomass burning, emissions from chemical precursors and the OH sink, it may be premature to neglect any direct contributions of land ecosystems to the CO budget. In addition, changes in global climate and resulting changes in global productivity may require re-evaluating older data and assumptions. One major reason for the large uncertainty is a general scarcity of empirical data. An additional factor contributing to the uncertainty is the lack of ecosystem-scale CO exchange measurements, i.e. CO flux data that encompass all sources and sinks within an ecosystem. Here we present data on continuous eddy covariance measurements of CO-fluxes above a managed mountain grassland in combination with soil chamber flux measurements, within- and above-canopy concentration profiles and an inverse Lagrangian analysis to disentangle sinks and sources of CO. Results show the grassland ecosystem to be a net source for CO during daytime, with increasing flux rates at higher solar radiation. At night, if at all, the meadow is a slight sink for CO. The same holds true regarding the soil flux measurements. Additionally, a two-month rainout experiment revealed hardly any differences in CO soil fluxes between rainout- and control-plots unless extremely dry conditions were reached.

  12. [Diurnal and seasonal variations of energy balance over Horqin meadow].

    PubMed

    Li, Hui-dong; Guan, De-Xin; Yuan, Feng-Hui; Ren, Yan; Wang, An-Zhi; Jin, Chang-Jie; Wu, Jia-Bing

    2014-01-01

    Based on the measurements of eddy flux and micrometeorological factors, this paper analyzed the diurnal and seasonal variations of energy balance over Horqin meadow. The results showed that annual energy balance ratio (EBR) of the eddy covariance system was 0.77, and EBR was biggest in growing season, middle in bare soil period and smallest in snow-covered period. Diurnal variations of energy components all presented bell-shaped curves. The peak of net radiation appeared around 12:00 and peaks of other components slightly lagged. Seasonal variation of net radiation presented a single-peak curve, and the annual average was 5.71 MJ x m(-2) x d(-1). Seasonal variation of latent heat flux was similar to that of net radiation, and the annual average was 2.84 MJ x m(-2) x d(-1). Seasonal variation of sensible heat flux presented a double-peak curve, and the peaks appeared in April and September, respectively. Annual averaged sensible heat flux was 1.87 MJ x m(-2) x d(-1). Maximum soil heat flux (3.47 MJ x m(-2) x d(-1)) appeared in April, and the soil heat flux became negative after September. Annual budget ratios of energy components presented a decreasing order of latent heat flux, sensible heat flux and soil heat flux, which accounted for 49.8%, 35.8% and 3.1% of net radiation, respectively. Seasonal variation of Bowen ratio (beta) presented a 'U' shape, and the annual average was 1.61. beta was small (0.18) and relatively stable in growing season, while it was large (2.39) and fluctuated severely in non-growing season.

  13. INTEGRATING GEOPHYSICS, GEOLOGY, AND HYDROLOGY TO DETERMINE BEDROCK GEOMETRY CONTROLS ON THE ORIGIN OF ISOLATED MEADOW COMPLEXES WITHIN THE CENTRAL GREAT BASIN, NEVADA

    EPA Science Inventory

    Riparian meadow complexes found in mountain ranges of the Central Great Basin physiographic region (western United States) are of interest to researchers as they contain significant biodiversity relative to the surrounding basin areas. These meadow complexes are currently degradi...

  14. Impact of the brine from a desalination plant on a shallow seagrass ( Posidonia oceanica) meadow

    NASA Astrophysics Data System (ADS)

    Gacia, Esperança; Invers, Olga; Manzanera, Marta; Ballesteros, Enric; Romero, Javier

    2007-05-01

    Although seawater desalination has increased significantly over recent decades, little attention has been paid to the impact of the main by-product (hypersaline water: brine) on ecosystems. In the Mediterranean, potentially the most affected ecosystems are meadows of the endemic seagrass Posidonia oceanica. We studied the effect of brine on a shallow P. oceanica meadow exposed to reverse osmosis brine discharge for more than 6 years. P. oceanica proved to be very sensitive to both eutrophication and high salinities derived from the brine discharge. Affected plants showed high epiphyte load and nitrogen content in the leaves, high frequencies of necrosis marks, low total non-structural carbohydrates and low glutamine synthetase activity, compared to control plants. However, there was no indication of extensive decline of the affected meadow. This is probably due to its very shallow situation, which results in high incident radiation as well as fast dilution and dispersion of the brine plume.

  15. Dugong dugon feeding in tropical Australian seagrass meadows: implications for conservation planning.

    PubMed

    Tol, Samantha J; Coles, Rob G; Congdon, Bradley C

    2016-01-01

    Dugongs (Dugong dugon) are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia.

  16. Dugong dugon feeding in tropical Australian seagrass meadows: implications for conservation planning

    PubMed Central

    Coles, Rob G.; Congdon, Bradley C.

    2016-01-01

    Dugongs (Dugong dugon) are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia. PMID:27441123

  17. Dugong dugon feeding in tropical Australian seagrass meadows: implications for conservation planning.

    PubMed

    Tol, Samantha J; Coles, Rob G; Congdon, Bradley C

    2016-01-01

    Dugongs (Dugong dugon) are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia. PMID:27441123

  18. Holocene dune formation at Ash Meadows National Wildlife Area, Nevada, USA

    USGS Publications Warehouse

    Lancaster, Nicholas; Mahan, Shannon

    2012-01-01

    Small isolated dune fields in the northern Mojave Desert are important centers of biodiversity and archaeological occupation sites. Currently dunes at Ash Meadows, Nevada, are stabilized by vegetation and are experiencing erosion of their upwind margins, indicating a negative sediment budget. New OSL ages from dunes at Ash Meadows indicate continuous eolian accumulation from 1.5 to 0.8 ka, with further accumulation around 0.2 ka. Prior studies (e.g., Mehringer and Warren, 1976) indicate periods of dune accumulation prior to 3.3 ka; 1.9–1 ka; and after 0.9 ka. These periods of eolian accumulation are largely synchronous with those identified elsewhere in the Mojave Desert. The composition of the Ash Meadows dunes indicates their derivation from regional fluvial sources, most likely during periods when axial washes were active as a result of enhanced winter precipitation.

  19. 75 FR 26747 - Meadow Lake Wind Farm III LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Meadow Lake Wind Farm III LLC; Supplemental Notice That Initial Market-Based... notice in the above-referenced proceeding of Meadow Lake Wind Farm III LLC's application for...

  20. 75 FR 26747 - Meadow Lake Wind Farm IV LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Meadow Lake Wind Farm IV LLC; Supplemental Notice That Initial Market-Based... notice in the above-referenced proceeding of Meadow Lake Wind Farm IV LLC's application for...

  1. The Turkish Standardization of the Meadow-Kendall Social-Emotional Assessment Inventory for Deaf and Hearing-Impaired Students

    ERIC Educational Resources Information Center

    Polat, Filiz

    2006-01-01

    The article present results of standardization of the Meadow-Kendall Social-Emotional Assessment Inventory for Deaf and Hearing-Impaired Students (Meadow, 1983), school-age version, for use in Turkey. The SEAI is a 59-item measure for assessing socioemotional adjustment of school-age deaf and hearing impaired students. A sample of 1,097 deaf…

  2. Meadow development of the seagrass Posidonia oceanica on the rocky seabed: a preliminary study in the Ligurian Sea.

    NASA Astrophysics Data System (ADS)

    Montefalcone, Monica; Vacchi, Matteo; Schiaffino, Chiara Francesca; Morri, Carla; Cristina, Carbone; Cabella, Roberto; Elter, Franco Marco; Nike Bianchi, Carlo; Ferrari, Marco

    2014-05-01

    Seagrass meadows are key ecosystems in coastal waters, influencing coastal zone features in terms of wave attenuation and shoreline stabilization. Landscape patterns observed in seagrass habitats are often associated with natural effects by waves or currents, as well as by human induced disturbances. Posidonia oceanica, the most important and abundant seagrass in the Mediterranean Sea, forms large meadows from the sea surface down to 40 m depth, colonizing a wide range of substratum typologies. Several studies have correlated the occurrence of P. oceanica meadows with sedimentological features, but few have investigated the role of substratum typology in shaping the geometry of a meadow. Meadows often develop on sand, but may also colonize rock. The present study relates geological parameters (structural, geotechnical, and mineralogical) of the rocky substrata with the development and characteristics of two shallow P. oceanica meadows in the Ligurian Sea (NW Mediterranean). Preliminary results show that the seagrass, in situations of high hydrodynamics, may colonize only specific lithotypes of the rocky substratum such as the clastic sedimentary rocks (mainly sandstone) that are characterized by low porosity and high values of strength. Under these conditions, the plant is capable to settle in areas with high hydrodynamics, where its development is usually prevented by lack of strong rhizome anchoring. When the upper portion of the meadow is installed on sub-verticalized layered rock, on which differential erosion acts, the arrangement of the more tenacious layers becomes the main element characterizing meadow geometry.

  3. A comparison between energy transfer and atmospheric turbulent exchanges over alpine meadow and banana plantation

    NASA Astrophysics Data System (ADS)

    Ding, Zhangwei; Ma, Yaoming; Wen, Zhiping; Ma, Weiqiang

    2016-04-01

    Banana plantation and alpine meadow ecosystems in southern China and the Tibetan Plateau are unique in the underlying surfaces they exhibit. In this study, we used eddy covariance and a micrometeorological tower to examine the characteristics of land surface energy exchanges over a banana plantation in southern China and an alpine meadow in the Tibetan Plateau from May 2010 to August 2012. The results showed that the diurnal and seasonal variations in upward shortwave radiation flux and surface soil heat flux were larger over the alpine meadow than over the banana plantation surface. Dominant energy partitioning varied with season. Latent heat flux was the main consumer of net radiation flux in the growing season, whereas sensible heat flux was the main consumer during other periods. The Monin-Obukhov similarity theory was employed for comparative purposes, using sonic anemometer observations of flow over the surfaces of banana plantations in the humid southern China monsoon region and the semi-arid areas of the TP, and was found to be applicable. Over banana plantation and alpine meadow areas, the average surface albedo and surface aerodynamic roughness lengths under neutral atmospheric conditions were ~0.128 and 0.47m, and ~0.223 and 0.01m, respectively. During the measuring period, the mean annual bulk transfer coefficients for momentum and sensible heat were 1.47×10-2 and 7.13×10-3, and 2.91×10-3 and 1.96×10-3, for banana plantation and alpine meadow areas, respectively. This is the first time in Asia that long-term open field measurements have been taken with the specific aim of making comparisons between banana plantation and alpine meadow surfaces.

  4. Cattle Grazing and Its Long-term Effects on Sedge Meadows

    USGS Publications Warehouse

    Middleton, Beth

    2004-01-01

    Most people think that wetlands are temporary, that they fill in by natural processes, and eventually become dry land. Some of these outdated ideas have come from the way that this subject has been covered in introductory textbooks in schools (Gibson, 1996). From these texts, we learned incorrectly that over time a lake fills with sediment or organic matter to become a wetland, which dries out to support shrubs and trees, and eventually it is no longer a wetland (Middleton, 1999; Middleton and others, 2004). These old ideas of how vegetation changes (succession) are no longer accepted. Wetland succession should be thought of as a cycle, with natural disturbance driving the changes, depending on the needs of the species. Succession is not something that changes a wetland into something that is not a wetland (Egler, 1978; van der Valk, 1981; Middleton and others, 1991; Klinger, 1996; Middleton, 1999). As an example of how disturbance changes wetlands, I have studied sedge meadows that have become invaded by shrubs after cattle (Bos sp.) have grazed them, in the Lodi Marsh State Natural Area, Wisconsin. Cattle disturbances allowed shrubs to invade sedge meadows, but the cattle also grazed on the shrubs, which kept them small. After the cows were removed, the plant species changed in the sedge meadow from the original sedges (fig. 1), to sedges mixed with growing small shrubs, and eventually to tall shrubs with very small amounts of sedge, called ?shrub carr? (Middleton, 2002a). Even though there has been a succession of plant types, the meadows, which began as wetlands, have remained wetlands. The settlers originally found the sedge meadows to be open ?sedge? lands and not shrubby. The settlers cut the sedges by hand to feed the cattle. Whitetailed deer (Odocoileus virginianus), though probably not bison (Bison bison), grazed these sedge meadows (Middleton 2002a).

  5. Composition of the essential oil of wild grown caraway in meadows of the Vienna region (Austria).

    PubMed

    Chizzola, Remigius

    2014-04-01

    The essential oil compositions of the different plant parts of wild growing caraway (Carum carvi, Apiaceae) were analyzed by GC/MS and GC/FID. The plants came from two meadows in the Vienna region, Austria. The oils from young fruits had a high proportion of limonene (61-83%), and those from inflorescences limonene (39-62%) and germacrene D (23-41%). The carvone contents of fruits, inflorescences and leaves varied greatly. Leaves and stems, low in volatiles, were dominated by germacrene D and germacrene A. Therefore, wild caraway appears as a valuable aromatic herb in meadows.

  6. Composition of the essential oil of wild grown caraway in meadows of the Vienna region (Austria).

    PubMed

    Chizzola, Remigius

    2014-04-01

    The essential oil compositions of the different plant parts of wild growing caraway (Carum carvi, Apiaceae) were analyzed by GC/MS and GC/FID. The plants came from two meadows in the Vienna region, Austria. The oils from young fruits had a high proportion of limonene (61-83%), and those from inflorescences limonene (39-62%) and germacrene D (23-41%). The carvone contents of fruits, inflorescences and leaves varied greatly. Leaves and stems, low in volatiles, were dominated by germacrene D and germacrene A. Therefore, wild caraway appears as a valuable aromatic herb in meadows. PMID:24868889

  7. TIOGA LAKE, HALL NATURAL AREA, LOG CABIN-SADDLEBAG, AND HORSE MEADOWS ROADLESS AREAS, CALIFORNIA.

    USGS Publications Warehouse

    Seitz, J.F.; Federspiel, F.E.

    1984-01-01

    Studies of the geology and mineral resources of the Tioga Lake, Hall Natural Area, Log Cabin-Saddlebag, and Horse Meadows Roadless Areas in California indicate that parts of the Log Cabin-Saddlebag and Hall Natural Roadless Areas have a substantiated resource potential for gold and (or) silver resources, and a probable potential for tungsten and molybdenum resources. Tioga Lake Roadless Area has little likelihood for the occurrence of mineral resources and the Horse Meadows Roadless Area has a probable potential for low-grade tungsten, gold, and (or) silver resources. The geologic terrane in the roadless areas precludes the occurrence of organic fuel resources.

  8. Androgenic induction of brain sexual dimorphism depends on photoperiod in meadow voles.

    PubMed

    Kelly, K K

    1993-02-01

    Male meadow voles maintained in a long photoperiod (LP) from birth have heavier brains than do females, but in short photoperiods (SP) this sex dimorphism is absent. Testosterone propionate (TP) administration on the second day of postnatal life produced significant increases in brain weight of LP but not SP females at 35 days of age. Short daylengths reduce the responsiveness of the meadow vole nervous system to the masculinizing effects of perinatal testosterone and may, in part, mediate the seasonally reduced sex difference in brain weight. PMID:8446686

  9. Inshore capture-based tuna aquaculture impact on Posidonia oceanica meadows in the eastern part of the Adriatic Sea.

    PubMed

    Kružić, Petar; Vojvodić, Vjeročka; Bura-Nakić, Elvira

    2014-09-15

    Mapping and monitoring of the seagrass Posidonia oceanica in the eastern (Croatian) part of the Adriatic Sea since 2004 indicates a significant decline in meadow density in an area impacted by inshore capture-based tuna aquaculture. The density and overall condition of P. oceanica meadows impacted by tuna farms near Fulija Islet was compared to two reference sites (Iž Island and Mrtovnjak Islet). The factors with the most significant influence on P. oceanica meadows were found to be the input of organic matter originating from the cages, as well as high epiphyte biomass caused by nutrient enrichment. Significant differences in nutrient concentrations were found between the sites impacted by tuna farms (Fulija Islet) and the control stations. Shoot density of the P. oceanica meadows decreased at the stations in close vicinity to the tuna farm, which suggests that the tuna farm activity strongly affected the surrounding meadows.

  10. Carbon monoxide fluxes over a managed mountain meadow

    NASA Astrophysics Data System (ADS)

    Hörtnagl, Lukas; Hammerle, Albin; Wohlfahrt, Georg

    2014-05-01

    Carbon monoxide (CO) is a toxic trace gas with an atmospheric lifetime of 1-3 months and an average atmospheric concentration of 100 ppb. CO mole fractions exhibit a pronounced seasonal cycle with lows in summer and highs in winter. Carbon monoxide has an indirect global warming potential by increasing the lifetime of methane (CH4), as the main sink of CO is the reaction with the hydroxyl (OH) radical, which in turn is also the main sink for CH4. Regarding the warming potential, it is estimated that 100 kg CO are equivalent to an emission of 5 kg CH4. In addition, carbon monoxide interferes with the building and destruction of ozone. Emission into and uptake from the atmosphere of CO are thus relevant for global climate and regional air quality. Sources and sinks of CO on a global scale are still highly uncertain, mainly due to general scarcity of empirical data and the lack of ecosystem-scale CO exchange measurements, i.e. CO flux data that encompass all sources and sinks within an ecosystem. Here we present eddy covariance CO fluxes over a managed temperate mountain grassland near Neustift, Austria, whereby volume mixing ratios of CO were quantified by a dual-laser mid-infrared quantum cascade laser (QCL). First analyses of fluxes captured in April 2013 showed that the QCL is well able to capture CO fluxes at the study site during springtime. During the same time period, both significant net uptake and deposition of CO were observed, with high emission and deposition fluxes on the order of +/- 5 nmol m-2 s-1, respectively. In addition, CO fluxes exhibited a clear diurnal cycle during certain time periods, indicating a continuous release or uptake of the compound with peak flux rates around noon. In this presentation, we will analyze 12 months of carbon monoxide fluxes between January and December 2013 with regard to possible abiotic and biotic drivers of CO exchange. As an additional step towards a full understanding of the greenhouse gas exchange of the meadow

  11. Mediating Water Temperature Increases Due to Livestock and Global Change in High Elevation Meadow Streams of the Golden Trout Wilderness

    PubMed Central

    Nusslé, Sébastien; Matthews, Kathleen R.; Carlson, Stephanie M.

    2015-01-01

    Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout Wilderness, California, we measured riparian vegetation and monitored water temperature in three meadow streams between 2008 and 2013, including two “resting” meadows and one meadow that is partially grazed. All three meadows have been subject to grazing by cattle and sheep since the 1800s and their streams are home to the imperiled California golden trout (Oncorhynchus mykiss aguabonita). In 1991, a livestock exclosure was constructed in one of the meadows (Mulkey), leaving a portion of stream ungrazed to minimize the negative effects of cattle. In 2001, cattle were removed completely from two other meadows (Big Whitney and Ramshaw), which have been in a “resting” state since that time. Inside the livestock exclosure in Mulkey, we found that riverbank vegetation was both larger and denser than outside the exclosure where cattle were present, resulting in more shaded waters and cooler maximal temperatures inside the exclosure. In addition, between meadows comparisons showed that water temperatures were cooler in the ungrazed meadows compared to the grazed area in the partially grazed meadow. Finally, we found that predicted temperatures under different global warming scenarios were likely to be higher in presence of livestock grazing. Our results highlight that land use can interact with climate change to worsen the local thermal conditions for taxa on the edge and that protecting riparian vegetation is likely to increase the resiliency of these ecosystems to climate change. PMID:26565706

  12. Mediating Water Temperature Increases Due to Livestock and Global Change in High Elevation Meadow Streams of the Golden Trout Wilderness.

    PubMed

    Nusslé, Sébastien; Matthews, Kathleen R; Carlson, Stephanie M

    2015-01-01

    Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout Wilderness, California, we measured riparian vegetation and monitored water temperature in three meadow streams between 2008 and 2013, including two "resting" meadows and one meadow that is partially grazed. All three meadows have been subject to grazing by cattle and sheep since the 1800s and their streams are home to the imperiled California golden trout (Oncorhynchus mykiss aguabonita). In 1991, a livestock exclosure was constructed in one of the meadows (Mulkey), leaving a portion of stream ungrazed to minimize the negative effects of cattle. In 2001, cattle were removed completely from two other meadows (Big Whitney and Ramshaw), which have been in a "resting" state since that time. Inside the livestock exclosure in Mulkey, we found that riverbank vegetation was both larger and denser than outside the exclosure where cattle were present, resulting in more shaded waters and cooler maximal temperatures inside the exclosure. In addition, between meadows comparisons showed that water temperatures were cooler in the ungrazed meadows compared to the grazed area in the partially grazed meadow. Finally, we found that predicted temperatures under different global warming scenarios were likely to be higher in presence of livestock grazing. Our results highlight that land use can interact with climate change to worsen the local thermal conditions for taxa on the edge and that protecting riparian vegetation is likely to increase the resiliency of these ecosystems to climate change.

  13. [Effects of nitrogen and phosphorous fertilization on community structure and productivity of degraded alpine meadows in northern Tibet, China].

    PubMed

    Zong, Ning; Shi, Pei-li; Niu, Ben; Jiang, Jing; Song, Ming-hua; Zhang, Xian-zhou; He, Yong-tao

    2014-12-01

    Abstract: Fertilization is an effective management measure for recovery of degraded grasslands. To better understand the effects of fertilization on community structure and productivity of lightly and severely degraded alpine meadows, we conducted a fertilization experiment in northern Tibet since 2008. The treatments were addition of nitrogen (N) alone (50 kg N x hm(-2) x a(-1), LN; 100 kg N x hm(-2) x a(-1), HN) or addition of both phosphorus (P) and N (50 kg N x hm(-2) x a(-1) +50 kg P x hm(-2) x a(-1), LN+P; 100 kg N x hm(-2) x a(-1) +50 kg P x hm(-2) x a(-1), HN+P) in each of the two types of degraded alpine meadows. N addition alone significantly affected plant community coverage or productivity in neither the slightly nor the severely degraded alpine meadow, while addition of both N and P significantly increased plant community coverage, aboveground and below- ground biomass of the alpine meadows. This suggested that productivity of this alpine meadow is co-limited by N and P. HN and HN+P significantly decreased species richness and evenness in the lightly degraded grassland, indicating that HN was not beneficial for the lightly degraded grassland to maintain species diversity and community stability. N addition significantly reduced the root to shoot ratio in the severely degraded meadow. In the lightly degraded meadow, N addition alone, especially with a high amount (HN) , enhanced the importance values (IV) and biomass of grasses, while fertilization with both N and P increased those of sedges. In the severely degraded meadow, fertilization had little effect on IV of grasses or sedges, but improved biomass of forbs. The results suggested that LN+P could be employed in recovery of lightly degraded alpine meadows, but other management measures such as fencing and reseeding may be needed for recovery of severely degraded alpine meadows.

  14. Mediating Water Temperature Increases Due to Livestock and Global Change in High Elevation Meadow Streams of the Golden Trout Wilderness.

    PubMed

    Nusslé, Sébastien; Matthews, Kathleen R; Carlson, Stephanie M

    2015-01-01

    Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout Wilderness, California, we measured riparian vegetation and monitored water temperature in three meadow streams between 2008 and 2013, including two "resting" meadows and one meadow that is partially grazed. All three meadows have been subject to grazing by cattle and sheep since the 1800s and their streams are home to the imperiled California golden trout (Oncorhynchus mykiss aguabonita). In 1991, a livestock exclosure was constructed in one of the meadows (Mulkey), leaving a portion of stream ungrazed to minimize the negative effects of cattle. In 2001, cattle were removed completely from two other meadows (Big Whitney and Ramshaw), which have been in a "resting" state since that time. Inside the livestock exclosure in Mulkey, we found that riverbank vegetation was both larger and denser than outside the exclosure where cattle were present, resulting in more shaded waters and cooler maximal temperatures inside the exclosure. In addition, between meadows comparisons showed that water temperatures were cooler in the ungrazed meadows compared to the grazed area in the partially grazed meadow. Finally, we found that predicted temperatures under different global warming scenarios were likely to be higher in presence of livestock grazing. Our results highlight that land use can interact with climate change to worsen the local thermal conditions for taxa on the edge and that protecting riparian vegetation is likely to increase the resiliency of these ecosystems to climate change. PMID:26565706

  15. AN INTERDISCIPLINARY APPROACH TO RIPARIAN MEADOW CHARACTERIZATION AND PRIORITIZATION, CENTRAL GREAT BASIN

    EPA Science Inventory

    The Great Basin Ecosystem Management Research group has described the hydrological, geophysical, and geomorphic conditions that lead to the formation and maintenance of riparian meadows of central Nevada. Previous work on these systems has focused on understanding a few study mea...

  16. 76 FR 54247 - Supawna Meadows National Wildlife Refuge, Salem County, NJ; Final Comprehensive Conservation Plan...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-31

    ... process for Supawna Meadows NWR. We started this process through a notice in the Federal Register (72 FR... requesting comments in a notice of availability in the Federal Register (75 FR 59287; September 27, 2010... alternatives were evaluated in our draft CCP/EA (75 FR 59287). The alternatives share some actions in...

  17. 75 FR 59287 - Supawna Meadows National Wildlife Refuge, Salem County, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-27

    ... Jersey. We will announce and post details of the public meetings in local news media, via our project... the Federal Register on September 24, 2007 (72 FR 54280). Supawna Meadows NWR currently includes 3,016.... Refuge visitors engage in wildlife observation and photography, hunting, and fishing. Portions of...

  18. Restoration potential of sedge meadows in hand-cultivated soybean fields in northeastern China

    USGS Publications Warehouse

    Wang, Guodong; Middleton, Beth; Jiang, Ming

    2013-01-01

    Sedge meadows can be difficult to restore from farmed fields if key structural dominants are missing from propagule banks. In hand-cultivated soybean fields in northeastern China, we asked if tussock-forming Carex and other wetland species were present as seed or asexual propagules. In the Sanjiang Plain, China, we compared the seed banks, vegetative propagules (below-ground) and standing vegetation of natural and restored sedge meadows, and hand-cultivated soybean fields in drained and flooded conditions. We found that important wetland species survived cultivation as seeds for some time (e.g. Calamogrostis angustifolia and Potamogeton crispus) and as field weeds (e.g. C. angustifolia and Phragmites australis). Key structural species were missing in these fields, for example, Carex meyeriana. We also observed that sedge meadows restored without planting or seeding lacked tussock-forming sedges. The structure of the seed bank was related to experimental water regime, and field environments of tussock height, thatch depth, and presence of burning as based on Nonmetric Multidimensional Scaling analysis. To re-establish the structure imposed by tussock sedges, specific technologies might be developed to encourage the development of tussocks in restored sedge meadows.

  19. Faunal communities and habitat characteristics of the Big Bend seagrass meadows, 2009-2010.

    EPA Science Inventory

    Seagrass meadows are important habitats that serve as nursery, feeding, and sheltering grounds for many marine species. In addition to the ecosystem functions and services they provide, seagrass habitats and associated fauna are commonly observed to have naturally high levels of...

  20. MANAGING AND RESTORING UPLAND RIPARIAN MEADOWS IN THE CENTRAL GREAT BASIN

    EPA Science Inventory

    Riparian meadow ecosystems in upland watersheds are of local and regional importance in the Great Basin. Covering only 1-3% of the total land area, these ecosystems contain a disproportionally large percentage of the region's biodiversity. Stream incision, due to natural and anth...

  1. Handbook for Students, Teachers and Parents. BOCES/SCOPE Outdoor Learning Laboratory at Sunken Meadow.

    ERIC Educational Resources Information Center

    Long Island State Park and Recreation Commission, NY.

    Since 1971 a fully equipped learning laboratory building and the open fields, woodlands, salt water marshes, and beaches of Sunken Meadow State Park have been available for year round day use by students and educators in New York's Suffolk and Nassau counties. Funded by the New York Office of Parks and Recreation and local Boards of Cooperative…

  2. Grade 9 Astronomy Study: Interests of Boys and Girls Studying Astronomy at Fletcher's Meadow Secondary School

    ERIC Educational Resources Information Center

    Krstovic, Mirjan; Brown, Laura; Chacko, Merin; Trinh, Brenda

    2008-01-01

    In this report, we discuss the interests of Grade 9 boys and girls studying astronomy at Fletcher's Meadow Secondary School in Brampton, Ontario. A total of 152 Grade 9 academic students were asked to rate their interest levels in various astronomy topics on a scale of 0-3, where 0 represented no interest and 3 represented a high level of…

  3. Evaluating mountain meadow groundwater response to pinyon-juniper and temperature in a great basin watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Expansion of deeply-rooted Pinyon-Juniper (PJ) has altered water partitioning and reduced water availability to discharging meadows. Research highlights the development and application of GSFLOW to a semi-arid, snow-dominated watershed in the Great Basin to evaluate PJ and temperature controls on mo...

  4. GEOMORPHIC AND HYDROGEOLOGICAL CONTROLS ON THE DISTRIBUTION OF WET MEADOWS IN THE CENTRAL GREAT BASIN

    EPA Science Inventory

    The Great Basin is an arid landscape dominated by dryland vegetation such as big sage and xeric grasses. Meadow complexes occur in mountain drainages and consist of discrete parcels of land up to several hectares in area that are characterized by high water tables and that primar...

  5. Bright Meadows: A Study of Teachers' Attitudes & Feelings in an Unorthodox School. Final Report.

    ERIC Educational Resources Information Center

    Zimmerman, Isa Kaftal

    This study dealt with a group of teachers in one particular untraditional school, Bright Meadows (fictitious name), and surveyed their responses, feelings, reactions to ideology, the environment and the events which constitute the school as a social institution. Data were gathered by means of a series of interviews based on peoples' memories; no…

  6. Septal oxytocin administration impairs peer affiliation via V1a receptors in female meadow voles.

    PubMed

    Anacker, Allison M J; Christensen, Jennifer D; LaFlamme, Elyssa M; Grunberg, Diana M; Beery, Annaliese K

    2016-06-01

    The peptide hormone oxytocin (OT) plays an important role in social behaviors, including social bond formation. In different contexts, however, OT is also associated with aggression, social selectivity, and reduced affiliation. Female meadow voles form social preferences for familiar same-sex peers under short, winter-like day lengths in the laboratory, and provide a means of studying affiliation outside the context of reproductive pair bonds. Multiple lines of evidence suggest that the actions of OT in the lateral septum (LS) may decrease affiliative behavior, including greater density of OT receptors in the LS of meadow voles that huddle less. We infused OT into the LS of female meadow voles immediately prior to cohabitation with a social partner to determine its effects on partner preference formation. OT prevented the formation of preferences for the partner female. Co-administration of OT with a specific OT receptor antagonist did not reverse the effect, but co-administration of OT with a specific vasopressin 1a receptor (V1aR) antagonist did, indicating that OT in the LS likely acted through V1aRs to decrease partner preference. Receptor autoradiography revealed dense V1aR binding in the LS of female meadow voles. These results suggest that the LS is a brain region that may be responsible for inhibitory effects of OT administration on affiliation, which will be important to consider in therapeutic administrations of OT. PMID:26974500

  7. Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows.

    PubMed

    Hicks, Damien M; Ouvrard, Pierre; Baldock, Katherine C R; Baude, Mathilde; Goddard, Mark A; Kunin, William E; Mitschunas, Nadine; Memmott, Jane; Morse, Helen; Nikolitsi, Maria; Osgathorpe, Lynne M; Potts, Simon G; Robertson, Kirsty M; Scott, Anna V; Sinclair, Frazer; Westbury, Duncan B; Stone, Graham N

    2016-01-01

    Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many 'pollinator-friendly' seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data

  8. Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows

    PubMed Central

    Hicks, Damien M.; Ouvrard, Pierre; Baldock, Katherine C. R.; Baude, Mathilde; Goddard, Mark A.; Kunin, William E.; Mitschunas, Nadine; Memmott, Jane; Morse, Helen; Nikolitsi, Maria; Osgathorpe, Lynne M.; Potts, Simon G.; Robertson, Kirsty M.; Scott, Anna V.; Sinclair, Frazer; Westbury, Duncan B.; Stone, Graham N.

    2016-01-01

    Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many ‘pollinator-friendly’ seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable

  9. Cattle grazing and its long-term effects on sedge meadows

    USGS Publications Warehouse

    Middleton, Beth

    2004-01-01

    Most people think that wetlands are temporary, that they fill in by natural processes, and eventually become dry land. Some of these outdated ideas have come from the way that this subject has been covered in introductory textbooks in schools (Gibson, 1996). From these texts, we learned incorrectly that over time a lake fills with sediment or organic matter to become a wetland, which dries out to support shrubs and trees, and eventually it is no longer a wetland (Middleton, 1999; Middleton and others, 2004). These old ideas of how vegetation changes (succession) are no longer accepted. Wetland succession should be thought of as a cycle, with natural disturbance driving the changes, depending on the needs of the species. Succession is not something that changes a wetland into something that is not a wetland (Egler, 1978; van der Valk, 1981; Middleton and others, 1991; Klinger, 1996; Middleton, 1999).As an example of how disturbance changes wetlands, I have studied sedge meadows that have become invaded by shrubs after cattle (Bos sp.) have grazed them, in the Lodi Marsh State Natural Area, Wisconsin. Cattle disturbances allowed shrubs to invade sedge meadows, but the cattle also grazed on the shrubs, which kept them small. After the cows were removed, the plant species changed in the sedge meadow from the original sedges (fig. 1), to sedges mixed with growing small shrubs, and eventually to tall shrubs with very small amounts of sedge, called “shrub carr” (Middleton, 2002a). Even though there has been a succession of plant types, the meadows, which began as wetlands, have remained wetlands. The settlers originally found the sedge meadows to be open “sedge” lands and not shrubby. The settlers cut the sedges by hand to feed the cattle. Whitetailed deer (Odocoileus virginianus), though probably not bison (Bison bison), grazed these sedge meadows (Middleton 2002a).Subsequent studies have explored methods to control invasive shrubs to restore the biodiversity of

  10. English Water Meadows: historic relics or focus for environmental management and inter-disciplinary research?

    NASA Astrophysics Data System (ADS)

    Cook, Hadrian

    2015-04-01

    Irrigated water meadows are found across Europe, from southern Scandinavia to Spain and in the Alpine regions and Italy. While the practice of engineering 'floated' meadow land for deliberate irrigation on hillsides and floodplains is widespread and ancient, since about 1600 AD the practice was widely adopted on floodplains in southern England where they improved the timing and productivity of grazing land and produced hay crops. They also became a part of English consciousness through art and literature. To some, water meadows are a relic of an agrarian past, to others they are the object of a range of foci for conservation, education, sustainable grass production, community engagement and recent research suggests water returned from meadow irrigation is beneficial to river water quality. Historically floodplain 'bedwork' water meadows grew from, and were integral in, the farming system of 'Wessex' involving sheep which produced dung for arable land and later supporting dairy and beef production, as well as hay. Where systems remain, this is largely due to the whim of individuals, the outcome of agri-environmental schemes. Water meadows may be managed by public, voluntary or private sector bodies. What is needed is a fresh look at how land owners, or communities, might micro-target them for heritage, habitat and grassland management. There are therefore interesting questions concerning their future: Who might invest in their restoration and maintenance? How might they be integrated into commercial farming? Are they of sufficient interest to restore en masse to become (once more) a major feature of the English chalk stream valleys? Do they provide a way into academic and public perception, combining environmental science, history, cultural heritage and environmental management? How might restoration and management become vehicles for public engagement? While each of these questions represents a major topic for discussion, this paper is an attempt to consolidate

  11. Hydroclimatic alteration increases vulnerability of montane meadows in the Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Viers, J. H.; Peek, R.; Purdy, S. E.; Emmons, J. D.; Yarnell, S. M.

    2012-12-01

    Meadow ecosystems of the Sierra Nevada (California, USA) have been maintained by the interplay of biotic and abiotic forces, where hydrological functions bridge aquatic and terrestrial realms. Meadows are not only key habitat for fishes, amphibians, birds, and mammals alike, but also provide enumerable ecosystem services to humans, not limited to regulating services (eg, water filtration), provisioning services (eg, grazing), and aesthetics. Using hydroclimatic models and spatial distribution models of indicator species, a range wide assessment was conducted to assess and synthesize the vulnerability of meadow ecosystems to hydroclimatic alteration, a result of regional climate change. Atmospheric warming is expected to result in a greater fraction of total precipitation falling as winter rain (rather than snow) and earlier snowmelt. These predicted changes will likely cause more precipitation-driven runoff in winter and reduced snowmelt runoff in spring, leading to reduced annual runoff and a general shift in runoff timing to earlier in the year. These profound effects have consequences for hydrological cycling and meadow functioning, though such changes will not occur steadily through time or uniformly across the range, and each individual meadow will respond as a function of its composition and land use history. Most vulnerable is groundwater recharge, a fundamental component of meadow hydrology. As a result of shortened snow melt period and absence of diel snowmelt fluxes that would otherwise gradually refill meadow aquifers, recharge is expected to decline due to less infiltration. Diminished water tables will likely stress hydric and mesic vegetation, promoting more xeric conditions. Coupled with greater magnitude stream flows, these conditions promote channel incision and ultimate state shift to non-meadow conditions. The biological effects of hydroclimatic alteration, such as lower mean annual flow and earlier timing, will result in an overall decrease in

  12. Effects of tourism and topography on vegetation diversity in the subalpine meadows of the Dongling Mountains of Beijing, China.

    PubMed

    Zhang, Jin-Tun; Xiang, ChunLing; Li, Min

    2012-02-01

    Subalpine meadows in the Dongling Mountains (located at E115º26'-115º40', N40º00'-40º05') of Beijing, China are important for tourism and the provision of ecosystem services. However, because of poor management serious degradation has occurred on these subalpine meadows. The aim of this paper is to present a quantitative analysis of effects of tourism disturbance and topography on the status and diversity of montane meadow communities and to provide direction for improved management. Sixty quadrats of 2 × 2 m(2) along 10 transects were set up to collect data on site characteristics and vegetation status. The relationships between community composition and structure, species diversity, and tourism disturbance and topographic variables were analyzed by multivariate methods (TWINSPAN and CCA). The results showed that eight meadow communities were identified by TWINSPAN. Most of them were seriously degraded. The first CCA axis identified an elevation and tourism disturbance intensity gradient, which illustrated that tourism disturbance and elevation were most important factors influencing meadow types, composition and structure. Some resistant species and response species to tourism disturbance were identified and can be used as indicator species of tourism disturbance. Species richness, heterogeneity and evenness were closely related to tourism disturbance and elevation. It is concluded that tourism disturbance must be controlled to enable grassland rehabilitation to occur in the meadows. Measures of effective management of the meadows were discussed.

  13. Seasonality in vegetation biometrics and its effects on sediment characteristics and meiofauna in Baltic seagrass meadows

    NASA Astrophysics Data System (ADS)

    Jankowska, Emilia; Włodarska-Kowalczuk, Maria; Kotwicki, Lech; Balazy, Piotr; Kuliński, Karol

    2014-02-01

    Seagrass meadows can act as ecosystem engineers, i.e., organisms that modify the availability of resources to other organisms. However, their possible positive impacts depend on the characteristics of the vegetation, and these can vary strongly seasonally. This study assesses seasonal variability in macrophyte taxonomic composition and seagrass biometrics in the temperate Baltic Sea eelgrass meadows. We hypothesize that the anticipated strong seasonality in vegetation cover induces parallel seasonal changes in seagrass engineering effects as indicated by changes in sediment characteristics and meiozoobenthic abundance, composition and diversity. Macrophytes, sediments, and fauna were sampled at two locations in the Puck Bay from vegetated bottoms and bare sands five times in one year. Zostera marina vegetation occurred throughout the year and showed strong seasonality with the highest values of shoot density, leaf length, and biomass in July (202.3 ± 30.0 95% CI shoots m-2) and the lowest in March (55.4 ± 15.0 shoots m-2). POC was significantly higher in vegetated sands, and these effects were evident throughout the study period regardless of variability in macrophyte vegetation. The density and diversity of meiofauna did not differ between the seagrass beds and bare sands even in summer months when vegetation was best developed. The lack of an effect of the seagrass meadows on the meiofauna can be explained by the relatively low shoot density and biomass of the studied seagrass meadows and/or higher macrobenthic predation on the vegetated bottom compared to bare sands. However, both the canopies of macrophytes and the effects of the vegetation on benthic systems could increase substantially over the course of the gradual, natural restoration of the seagrass meadows.

  14. Predicted effects of proposed new regulation plans on sedge/grass meadows of Lake Ontario

    USGS Publications Warehouse

    Wilcox, D.A.; Xie, Y.

    2008-01-01

    Previously described models for predicting the percent of Lake Ontario wetlands that would be occupied by sedge/grass-dominated meadow marsh were used to test four proposed new plans for regulation of lake levels and to make comparisons with the current plan and unregulated conditions. The models for drowned river mouth, barrier beach, open embayment, and protected embayment wetlands assessed responses to lake levels that would be generated by each plan under net total supplies modified from those that occurred from1900 to 2000. In years when reduced supplies would allow meadow marsh regeneration, simulated unregulated lake levels produced the most meadow marsh in all wetland geomorphic types; current Plan 1958DD produced the least. Overall predicted percent meadow marsh under the test plans decreased in the order B+, 2007, D+, and A+, and the latter three plans produced rather similar results in many cases. Lower percentages of meadow marsh under some plans were due to insufficient low lake levels that could allow soils to dry and restrict invasion by cattails, as well as lack of periodic high lake levels that could kill invading upland plants. An assessment of seasonal lake-level characteristics demonstrated that Plan 2007 would reduce mean winter lake levels by 13 cm or more than Plan B+ and springtime lake levels by more than 10 cm. These seasonal differences could result in less winter habitat for muskrats and reduced access to spring spawning habitats for fish such as northern pike. Our model results provide important information for use in the process of selecting a new regulation plan for Lake Ontario.

  15. Plant species dominance shifts across erosion edge-meadow transects in the Swiss Alps.

    PubMed

    Huck, Corinne; Körner, Christian; Hiltbrunner, Erika

    2013-03-01

    While exerting no obvious function under "average" environmental conditions, the presence of certain plant specialists becomes crucial in the event of a complete failure of a community due to severe disturbance such as landslides. Plants capable of growing at erosion edges may act as potential edge-engineers by coping with unstable ground and stabilizing the soil with their roots. We hypothesized that life conditions at erosion edges select for a particular set of specialists or species with specific traits, the identification of which was the aim of the study. Across 17 small-scale transects (0.40 × 1.60 m) from intact meadows to landslide edges (Ursern Valley, Swiss Alps, c. 1,600 m a.s.l.), we quantified plant species abundance by the point intercept method and characterized growth conditions based on Landolt's indicator values, leaf δ(13)C, and volumetric soil moisture in the uppermost soil layers. We observed a clear change of plant species composition and relative abundance from the meadow to the edge, presumably induced by the 25 % lower soil moisture and microclimatic exposure. Species richness at the edge was two-thirds of that in the meadow, but was positively correlated with species richness of the adjacent meadow. Species with "edge-preference" had either (1) rolled or festucoid leaves like Festuca spp., Avenella flexuosa and Nardus stricta, or (2) small, scleromorphic leaves like Vaccinium vitis-idaea, Calluna vulgaris and Thymus ssp. Graminoids with rolled/festucoid leaves were found to be the most dominant edge-specialists. The grass Festuca valesiaca s.l. emerged as the most dominant plant species at the edge, having an 11-times higher cover at the edge than in the meadow. In this montane grassland, a single species contributes to the stabilization of erosion edges and may be regarded as a potential keystone species for slope stability and regeneration after landslides even its role has not so far been established.

  16. Identifying Components of Groundwater Flow, Flux, and Storage in Tuolumne Meadows, Yosemite, California

    NASA Astrophysics Data System (ADS)

    Vialpando, M., III; Lowry, C.; Visser, A.; Moran, J. E.; Esser, B. K.

    2015-12-01

    High elevation meadows in the Sierra Nevada of California, USA represent mixing zones between surface water and groundwater. Quantifying the exchange between stream water and groundwater, and the residence time of water stored in meadow sediments will allow examination of the possible buffer effect that groundwater has on meadows and streams. This in turn has implications for the resilience of the ecosystem as well as the downstream communities that are dependent upon runoff for water supply. Stream flow was measured and water samples were collected along a 5 km reach of the Tuolumne River and adjacent wells during both spring runoff and baseflow. Water samples were analyzed for concentrations of dissolved noble gases and anions, sulfur-35, tritium and radon to study surface water-groundwater interactions and residence times. Although lower than average because of the ongoing drought in California, discharge in early July 2015 was about 35 times that measured during the previous fall. During baseflow, a small component of fracture flow (2%) is identified using dissolved helium. Radon, anions and stream discharge identify reaches of groundwater discharge. Anions show a steady increase in the groundwater component over the western portion of the meadow during baseflow, and over 50% of stream water is exchanged with meadow groundwater, without a net gain or loss of stream flow. Sulfur-35 and tritium results indicated that groundwater contributing to stream flow has recharged within the previous two years. With the current drought, estimated as the most severe in 1200 years, accurate estimations of water availability are becoming increasingly important to water resource managers.

  17. A comparison between energy transfer and atmospheric turbulent exchanges over alpine meadow and banana plantation

    NASA Astrophysics Data System (ADS)

    Ding, Zhangwei; Ma, Yaoming; Wen, Zhiping; Ma, Weiqiang; Chen, Shiji

    2016-03-01

    Banana plantation and alpine meadow ecosystems in southern China and the Tibetan Plateau (TP) are unique in the underlying surfaces they exhibit. In this study, we used eddy covariance and a micrometeorological tower to examine the characteristics of land surface energy exchanges over a banana plantation in southern China and an alpine meadow in the Tibetan Plateau from May 2010 to August 2012. The results showed that the diurnal and seasonal variations in upward shortwave radiation flux and surface soil heat flux were larger over the alpine meadow than over the banana plantation surface. Dominant energy partitioning varied with season. Latent heat flux was the main consumer of net radiation flux in the growing season, whereas sensible heat flux was the main consumer during other periods. The Monin-Obukhov similarity theory was employed for comparative purposes, using sonic anemometer observations of flow over the surfaces of banana plantations in the humid southern China monsoon region and the semi-arid areas of the TP, and was found to be applicable. Over banana plantation and alpine meadow areas, the average surface albedo and surface aerodynamic roughness lengths under neutral atmospheric conditions were ˜0.128 and 0.47 m, and ˜0.223 and 0.01 m, respectively. During the measuring period, the mean annual bulk transfer coefficients for momentum and sensible heat were 1.47 × 10-2 and 7.13 × 10-3, and 2.91 × 10-3 and 1.96 × 10-3, for banana plantation and alpine meadow areas, respectively.

  18. Deterioration of eelgrass, Zostera marina L., meadows by water pollution in Seto Inland Sea, Japan.

    PubMed

    Tamaki, Hitoshi; Tokuoka, Makoto; Nishijima, Wataru; Terawaki, Toshinobu; Okada, Mitsumasa

    2002-11-01

    Survival of transplanted Zostera marina L. (eelgrass) and environmental conditions (water quality, bottom sediments, sedimentation on leaves and flow regime) were studied concurrently in the center, edge, and at the outside of a eelgrass meadow located in a eutrophic coastal zone in northern Hiroshima Bay, Seto Inland Sea, Japan. Eelgrass transplants at the outside of the meadow declined significantly, whereas those at the center were consistently well established. Silt content in the bottom sediments at the outside was higher than that at the center. The sediment was oxic from the surface to 2 cm deep at the center, whereas those at the edge and the outside were reductive almost from the surface. The sediment characteristics typical in eutrophic water seemed to be a factor responsible for the deterioration of eelgrass meadows. Although suspended solid concentrations in the water columns were almost the same, the amount of sediments deposited on leaves of eelgrass at the outside was higher than that at the center of the meadow. The amount of the deposition at the outside seems to be enough to inhibit photosynthesis; i.e. photosynthetic photon flux density (PPFD) available for eelgrass was only 36% of that without any deposition. The deposition in the center, however, was small enough to allow 84% of the original PPFD. Flow rates, determined at 30 cm above the bottom, a half height of average eelgrass, suggested that the rate at the outside was not enough to remove deposited sediments from the surface of eelgrass leaves. Thus, the large amount of sediment deposition caused by water pollution and/or eutrophication seemed to be another factor to inhibit the survival of eelgrass at the outside edge of the meadow.

  19. Plant species dominance shifts across erosion edge-meadow transects in the Swiss Alps.

    PubMed

    Huck, Corinne; Körner, Christian; Hiltbrunner, Erika

    2013-03-01

    While exerting no obvious function under "average" environmental conditions, the presence of certain plant specialists becomes crucial in the event of a complete failure of a community due to severe disturbance such as landslides. Plants capable of growing at erosion edges may act as potential edge-engineers by coping with unstable ground and stabilizing the soil with their roots. We hypothesized that life conditions at erosion edges select for a particular set of specialists or species with specific traits, the identification of which was the aim of the study. Across 17 small-scale transects (0.40 × 1.60 m) from intact meadows to landslide edges (Ursern Valley, Swiss Alps, c. 1,600 m a.s.l.), we quantified plant species abundance by the point intercept method and characterized growth conditions based on Landolt's indicator values, leaf δ(13)C, and volumetric soil moisture in the uppermost soil layers. We observed a clear change of plant species composition and relative abundance from the meadow to the edge, presumably induced by the 25 % lower soil moisture and microclimatic exposure. Species richness at the edge was two-thirds of that in the meadow, but was positively correlated with species richness of the adjacent meadow. Species with "edge-preference" had either (1) rolled or festucoid leaves like Festuca spp., Avenella flexuosa and Nardus stricta, or (2) small, scleromorphic leaves like Vaccinium vitis-idaea, Calluna vulgaris and Thymus ssp. Graminoids with rolled/festucoid leaves were found to be the most dominant edge-specialists. The grass Festuca valesiaca s.l. emerged as the most dominant plant species at the edge, having an 11-times higher cover at the edge than in the meadow. In this montane grassland, a single species contributes to the stabilization of erosion edges and may be regarded as a potential keystone species for slope stability and regeneration after landslides even its role has not so far been established. PMID:23337968

  20. Cuticular waxes in alpine meadow plants: climate effect inferred from latitude gradient in Qinghai-Tibetan Plateau.

    PubMed

    Guo, Yanjun; Guo, Na; He, Yuji; Gao, Jianhua

    2015-09-01

    Alpine meadow ecosystems are susceptible to climate changes. Still, climate impact on cuticular wax in alpine meadow plants is poorly understood. Assessing the variations of cuticular wax in alpine meadow plants across different latitudes might be useful for predicting how they may respond to climate change. We studied nine alpine meadows in a climate gradient in the east side of Qinghai-Tibetan Plateau, with mean annual temperature ranging from -7.7 to 3.2°C. In total, 42 plant species were analyzed for cuticular wax, averaged 16 plant species in each meadow. Only four plant species could be observed in all sampling meadows, including Kobresia humilis,Potentilla nivea,Anaphalis lacteal, and Leontopodium nanum. The amounts of wax compositions and total cuticular wax in the four plant species varied among sampling meadows, but no significant correlation could be observed between them and temperature, precipitation, and aridity index based on plant species level. To analyze the variations of cuticular wax on community level, we averaged the amounts of n-alkanes, aliphatic acids, primary alcohols, and total cuticular wax across all investigated plant species in each sampling site. The mean annual temperature, mean temperature in July, and aridity index were significantly correlated with the averaged amounts of wax compositions and total cuticular wax. The average chain length of n-alkanes in both plant and soil linearly increased with increased temperature, whereas reduced with increased aridity index. No significant correlation could be observed between mean annual precipitation and mean precipitation from June to August and the cuticular wax amounts and average chain length. Our results suggest that the survival of some alpine plants in specific environments might be depended on their abilities in adjusting wax deposition on plant leaves, and the alpine meadow plants as a whole respond to climate change, benefiting the stability of alpine meadow ecosystem.

  1. Geographic variability in organic carbon stock and accumulation rate in sediments of East and Southeast Asian seagrass meadows

    NASA Astrophysics Data System (ADS)

    Miyajima, Toshihiro; Hori, Masakazu; Hamaguchi, Masami; Shimabukuro, Hiromori; Adachi, Hiroshi; Yamano, Hiroya; Nakaoka, Masahiro

    2015-04-01

    Organic carbon (OC) stored in the sediments of seagrass meadows has been considered a globally significant OC reservoir. However, the sparsity and regional bias of studies on long-term OC accumulation in coastal sediments have limited reliable estimation of the capacity of seagrass meadows as a global OC sink. We evaluated the amount and accumulation rate of OC in sediment of seagrass meadows and adjacent areas in East and Southeast Asia. In temperate sites, the average OC concentration in the top 30 cm of sediment was higher in seagrass meadows (780-1080 mmol g-1) than in sediments without seagrass cover (52-430 mmol g-1). The average OC in the top 30 cm of subtropical and tropical seagrass meadow sediments ranged from 140 to 440 mmol g-1. Carbon isotope mass balancing suggested that the contribution of seagrass-derived carbon to OC stored in sediments was often relatively minor (temperate: 10-40%; subtropical: 35-82%; tropical: 4-34%) and correlated to the habitat type, being particularly low in estuarine habitats. Stock of OC in the top meter of sediment of all the studied meadows ranged from 38 to 120 Mg ha-1. The sediment accumulation rates were estimated by radiocarbon dating of six selected cores (0.32-1.34 mm yr-1). The long-term OC accumulation rates calculated from the sediment accumulation rate and the top 30 cm average OC concentration for the seagrass meadows (24-101 kg ha-1 yr-1) were considerably lower than the OC accumulation rates previously reported for Mediterranean Posidonia oceanica meadows (580 kg ha-1 yr-1 on average). Current estimates for the global carbon sink capacity of seagrass meadows, which rely largely on Mediterranean studies, may be considerable overestimations.

  2. Hydrographic and sediment characteristics of seagrass meadows of the Gulf of Mannar Marine Biosphere Reserve, South India.

    PubMed

    Arumugam, Radjassegarin; Kannan, Rengasamy Ragupathi Raja; Saravanan, Kannan Rajasekaran; Thangaradjou, Thirunavukarasu; Anantharaman, Perumal

    2013-10-01

    The aim of the study was to examine the spatial and temporal variations in the physicochemical parameters of seagrass meadows of the Gulf of Mannar, South India using multivariate statistical techniques, namely, cluster analysis (CA) and principal component analysis (PCA), to explore the relationship. There were clear spatial and temporal variations in physicochemical variables of the seagrass meadow of the Gulf of Mannar, but such changes were subjected to seasonal variations especially during monsoon and post-monsoon seasons. The multivariate statistical techniques, viz., CA and PCA helped in the discrimination of islands according to the physicochemical parameters of the seagrass meadows. It was inferred that electrical conductivity, nitrate, particulate organic carbon, and phosphate strongly determined the discrimination of 19 islands, respectively, upon physicochemical characteristics of their seagrass meadows. These results highlight the important role of seagrasses in the Gulf of Mannar Marine Biosphere Reserve.

  3. HYDROGEOLOGIC SETTING AND CHARACTERISTICS OF RIPARIAN MEADOW COMPLEXES IN THE MOUNTAINS OF CENTRAL NEVADA: A CASE STUDY

    EPA Science Inventory

    Riparian wet meadow complexes in the mountains of the central Great Basin are scarce, ecologically important systems threatened by stream incision. An interdisciplinary team from government and academia is investigating the origin, setting, and biological--physical interrelations...

  4. Using MODIS data for understanding changes in seagrass meadow health: a case study in the Great Barrier Reef (Australia).

    PubMed

    Petus, Caroline; Collier, Catherine; Devlin, Michelle; Rasheed, Michael; McKenna, Skye

    2014-07-01

    Stretching more than 2000 km along the Queensland coast, the Great Barrier Reef Marine Park (GBR) shelters over 43,000 square km of seagrass meadows. Despite the status of marine protected area and World Heritage listing of the GBR, local seagrass meadows are under stress from reduced water quality levels; with reduction in the amount of light available for seagrass photosynthesis defined as the primary cause of seagrass loss throughout the GBR. Methods have been developed to map GBR plume water types by using MODIS quasi-true colour (hereafter true colour) images reclassified in function of their dominant colour. These data can be used as an interpretative tool for understanding changes in seagrass meadow health (as defined in this study by the seagrass area and abundance) at different spatial and temporal scales. We tested this method in Cleveland Bay, in the northern GBR, where substantial loss in seagrass area and biomass was detected by annual monitoring from 2007 to 2011. A strong correlation was found between bay-wide seagrass meadow area and biomass and exposure to turbid Primary (sediment-dominated) water type. There was also a strong correlation between the changes of biomass and area of individual meadows and exposure of seagrass ecosystems to Primary water type over the 5-year period. Seagrass meadows were also grouped according to the dominant species within each meadow, irrespective of location within Cleveland Bay. These consolidated community types did not correlate well with the exposure to Primary water type, and this is likely to be due to local environmental conditions with the individual meadows that comprise these groupings. This study proved that remote sensing data provide the synoptic window and repetitivity required to investigate changes in water quality conditions over time. Remote sensing data provide an opportunity to investigate the risk of marine-coastal ecosystems to light limitation due to increased water turbidity when in situ

  5. Using MODIS data for understanding changes in seagrass meadow health: a case study in the Great Barrier Reef (Australia).

    PubMed

    Petus, Caroline; Collier, Catherine; Devlin, Michelle; Rasheed, Michael; McKenna, Skye

    2014-07-01

    Stretching more than 2000 km along the Queensland coast, the Great Barrier Reef Marine Park (GBR) shelters over 43,000 square km of seagrass meadows. Despite the status of marine protected area and World Heritage listing of the GBR, local seagrass meadows are under stress from reduced water quality levels; with reduction in the amount of light available for seagrass photosynthesis defined as the primary cause of seagrass loss throughout the GBR. Methods have been developed to map GBR plume water types by using MODIS quasi-true colour (hereafter true colour) images reclassified in function of their dominant colour. These data can be used as an interpretative tool for understanding changes in seagrass meadow health (as defined in this study by the seagrass area and abundance) at different spatial and temporal scales. We tested this method in Cleveland Bay, in the northern GBR, where substantial loss in seagrass area and biomass was detected by annual monitoring from 2007 to 2011. A strong correlation was found between bay-wide seagrass meadow area and biomass and exposure to turbid Primary (sediment-dominated) water type. There was also a strong correlation between the changes of biomass and area of individual meadows and exposure of seagrass ecosystems to Primary water type over the 5-year period. Seagrass meadows were also grouped according to the dominant species within each meadow, irrespective of location within Cleveland Bay. These consolidated community types did not correlate well with the exposure to Primary water type, and this is likely to be due to local environmental conditions with the individual meadows that comprise these groupings. This study proved that remote sensing data provide the synoptic window and repetitivity required to investigate changes in water quality conditions over time. Remote sensing data provide an opportunity to investigate the risk of marine-coastal ecosystems to light limitation due to increased water turbidity when in situ

  6. Organic farming favours insect-pollinated over non-insect pollinated forbs in meadows and wheat fields.

    PubMed

    Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F; Tscharntke, Teja

    2013-01-01

    The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators.

  7. Resilience and stability of Cymodocea nodosa seagrass meadows over the last four decades in a Mediterranean lagoon

    NASA Astrophysics Data System (ADS)

    Garrido, Marie; Lafabrie, Céline; Torre, Franck; Fernandez, Catherine; Pasqualini, Vanina

    2013-09-01

    Understanding what controls the capacity of a coastal lagoon ecosystem to recover following climatic and anthropogenic perturbations and how these perturbations can alter this capacity is critical to efficient environmental management. The goal of this study was to examine the resilience and stability of Cymodocea nodosa-dominated seagrass meadows in Urbino lagoon (Corsica, Mediterranean Sea) by characterizing the spatio-temporal dynamics of seagrass meadows over a 40-year period and comparing (anthropogenic and climatic) environmental fluctuations. The spatio-temporal evolution of seagrass meadows was investigated using previous maps (1973, 1979, 1990, 1994, 1996, 1999) and a 2011 map realized by aerial photography-remote sensing combined with GIS technology. Environmental fluctuation was investigated via physical-chemical parameters (rainfall, water temperature, salinity, turbidity, dissolved oxygen) and human-impact changes (aquaculture, artificial channel). The results showed a severe decline (estimated at -49%) in seagrass meadows between 1973 and 1994 followed by a period of strong recovery (estimated to +42%) between 1994 and 2011. Increased turbidity, induced either by rainfall events, dredging or phytoplankton growth, emerged as the most important driver of the spatio-temporal evolution of Cymodocea nodosa-dominated meadows in Urbino lagoon over the last four decades. Climate events associated to increased turbidity and reduced salinity and temperature could heavily impact seagrass dynamics. This study shows that Urbino lagoon, a system relatively untouched by human impact, shelters seagrass meadows that exhibit high resilience and stability.

  8. The chemical control of Sorghum halepense species in sunflower culture, in the Danube meadow.

    PubMed

    Poienaru, S; Sarpe, N; Sarpe, I

    2005-01-01

    In the latest years, sunflower was cultivated in Romania on an area of 800-900 thousand hectares. On 100 or 150 thousand hectares we find it cultivated also in agricultural farms in the Danube Meadow, because sunflower has favorable conditions on these soils, productions exceeding sometimes over 4000 kg/ha, of course, in irrigation conditions. In the Danube Meadow, the first experiments on Sorghum halepense (Johnson grass) species were performed by Fane Popa and colleagues (1986), at the agricultural station of Braila, using the herbicide Fusilade. In our experiments, the herbicide fusillade was compared with different more recently synthesized herbicides: Super, Pantera, Agil, Select, with the specific purpose of identifying the most favorable dose.

  9. The chemical control of Shorgum halepense (Johnson grass) in soybean culture in the Danube meadow.

    PubMed

    Poienaru, S; Sarpe, N; Sarpe, I

    2005-01-01

    Soybean cultures, especially those from the Danube Meadow, are very strongly infested with Johnson grass, which causes big damages, by the reduction of production with 40-85%, depending on the infestation degree. Before the synthesis of special herbicides for Johnson grass control, this species was controlled by practicing deep tilling, repeated operations with the disk, and, after the sprouting of soy plants, by mechanical and manual hoeings. In the Danube Waterside, the lack of labour force for the manual hoeing is very sharp. For this reason, it was generalized the enlarged use of herbicides for annual weed control (monocotyledonous and dicotyledonous), including Johnson grass. For the control of Johnson grass species, in the conditions of the Danube Meadow, the best results were obtained with the herbicides Fusilade Super, Targa Super, Agil and Select, and for the control of annual dicotyledonous species, with the herbicide Pivot 100LC.

  10. Grazing intensifies degradation of a Tibetan Plateau alpine meadow through plant-pest interaction.

    PubMed

    Cao, Hui; Zhao, Xinquan; Wang, Shiping; Zhao, Liang; Duan, Jichuang; Zhang, Zhenhua; Ge, Shidong; Zhu, Xiaoxue

    2015-06-01

    Understanding the plant-pest interaction under warming with grazing conditions is critical to predict the response of alpine meadow to future climate change. We investigated the effects of experimental warming and grazing on the interaction between plants and the grassland caterpillar Gynaephora menyuanensis in an alpine meadow on the Tibetan Plateau in 2010 and 2011. Our results showed that grazing significantly increased nitrogen concentration in graminoids and sward openness with a lower sward height, sward coverage, and plant litter mass in the community. Grazing significantly increased G. menyuanensis body size and potential fecundity in 2010. The increases in female body size were about twofold greater than in males. In addition, grazing significantly increased G. menyuanensis density and its negative effects on aboveground biomass and graminoid coverage in 2011. We found that G. menyuanensis body size was significantly positively correlated with nitrogen concentration in graminoids but negatively correlated with plant litter mass. Even though warming did not significantly increased G. menyuanensis performance and the negative effects of G. menyuanensis on alpine meadow, the increases in G. menyuanensis growth rate and its negative effect on aboveground biomass under the warming with grazing treatment were significantly higher than those under the no warming with grazing treatment. The positive effects of grazing on G. menyuanensis performance and its damage were exacerbated by the warming treatment. Our results suggest that the fitness of G. menyuanensis would increase under future warming with grazing conditions, thereby posing a greater risk to alpine meadow and livestock production. PMID:26120436

  11. Assessment and physiological state of the Posidonia oceanica meadows in Porto Cristo (Manacor, Spain)

    NASA Astrophysics Data System (ADS)

    Sureda, Antoni; Box, Antonio; Tejada, Silvia

    2015-12-01

    In the Mediterranean Sea, Posidonia oceanica is the main seagrass meadow that brings food and shelter to many species. The P. oceanica deterioration is an indicator of its own status, since it is sensitive to many disturbances, such as human impacts or alien species. Lately, oxidative stress has been pointed out as another possible biomarker of the animal and plant status. The aim of this work was to evaluate the physiological status of the P. oceanica meadows in the Porto Cristo bay (Manacor, Mallorca, Balearic Islands, Western Mediterranean), evaluating the possible impact induced by human activity performed in the area. In situ measurements were quantified (shoot density, and the maximum length and width of P. oceanica leaves) by scuba divers. Leaf samples were collected to determine the catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. The malondialdehyde (MDA) level as marker of lipid peroxidation was also evaluated. Shoot density, and length and width measurements of the leaves in the inner locations of the bay showed inferior structural features than the leaves from the outer areas. CAT, SOD and GPx enzymatic activities and lipid peroxidation were higher in leaves from the internal zones than in the outer placements. In conclusion, the general status of the of P. oceanica meadows on the Porto Cristo Bay according to structural and oxidative biomarkers evidenced a good physiological condition, although the areas nearest to the harbour and the beach reflect signs of human affection. Altogether, it reflects a good physiological condition of the meadows in the external areas of the Porto Cristo Bay.

  12. The acceptability of meadow plants to the slug Deroceras reticulatum and implications for grassland restoration

    PubMed Central

    Barlow, Sarah E.; Close, Andrew J.; Port, Gordon R.

    2013-01-01

    Background and Aims Despite the selective pressure slugs may exert on seedling recruitment there is a lack of information in this context within grassland restoration studies. Selective grazing is influenced by interspecific differences in acceptability. As part of a larger study of how slug–seedling interactions may influence upland hay meadow restoration, an assessment of relative acceptability is made for seedlings of meadow plants to the slug, Deroceras reticulatum. Methods Slug feeding damage to seedling monocultures of 23 meadow species and Brassica napus was assessed in microcosms over 14 d. The severity and rate of damage incurred by each plant species was analysed with a generalized additive mixed model. Plant species were then ranked for their relative acceptability. Key Results Interspecific variation in relative acceptability suggested seedlings of meadow species form a hierarchy of acceptability to D. reticulatum. The four most acceptable species were Achillea millefolium and the grasses Holcus lanatus, Poa trivialis and Festuca rubra. Trifolium pratense was acceptable to D. reticulatum and was the second highest ranking forb species. The most unacceptable species were mainly forbs associated with the target grassland, and included Geranium sylvaticum, Rumex acetosa, Leontodon hispidus and the grass Anthoxanthum odoratum. A strong positive correlation was found for mean cumulative feeding damage and cumulative seedling mortality at day 14. Conclusions Highly unacceptable species to D. reticulatum are unlikely to be selectively grazed by slugs during the seedling recruitment phase, and were predominantly target restoration species. Seedlings of highly acceptable species may be less likely to survive slug herbivory and contribute to seedling recruitment at restoration sites. Selective slug herbivory, influenced by acceptability, may influence community-level processes if seedling recruitment and establishment of key functional species, such as T

  13. Grazing intensifies degradation of a Tibetan Plateau alpine meadow through plant–pest interaction

    PubMed Central

    Cao, Hui; Zhao, Xinquan; Wang, Shiping; Zhao, Liang; Duan, Jichuang; Zhang, Zhenhua; Ge, Shidong; Zhu, Xiaoxue

    2015-01-01

    Understanding the plant–pest interaction under warming with grazing conditions is critical to predict the response of alpine meadow to future climate change. We investigated the effects of experimental warming and grazing on the interaction between plants and the grassland caterpillar Gynaephora menyuanensis in an alpine meadow on the Tibetan Plateau in 2010 and 2011. Our results showed that grazing significantly increased nitrogen concentration in graminoids and sward openness with a lower sward height, sward coverage, and plant litter mass in the community. Grazing significantly increased G. menyuanensis body size and potential fecundity in 2010. The increases in female body size were about twofold greater than in males. In addition, grazing significantly increased G. menyuanensis density and its negative effects on aboveground biomass and graminoid coverage in 2011. We found that G. menyuanensis body size was significantly positively correlated with nitrogen concentration in graminoids but negatively correlated with plant litter mass. Even though warming did not significantly increased G. menyuanensis performance and the negative effects of G. menyuanensis on alpine meadow, the increases in G. menyuanensis growth rate and its negative effect on aboveground biomass under the warming with grazing treatment were significantly higher than those under the no warming with grazing treatment. The positive effects of grazing on G. menyuanensis performance and its damage were exacerbated by the warming treatment. Our results suggest that the fitness of G. menyuanensis would increase under future warming with grazing conditions, thereby posing a greater risk to alpine meadow and livestock production. PMID:26120436

  14. Long-term effect of beach replenishment on natural recovery of shallow Posidonia oceanica meadows

    NASA Astrophysics Data System (ADS)

    González-Correa, José M.; Torquemada, Yolanda Fernández; Sánchez Lizaso, José Luis

    2008-03-01

    The recovery capacity of shallow Posidonia oceanica meadows degraded by beach replenishment eighteen years before was assessed in two impacted meadows and compared with other two undisturbed localities. Inside each locality, we selected randomly three sites separated by 500-1000 m. At site level we study the vitality of P. oceanica meadow assessing the vegetative growth, leaf characteristics, and non-structural carbohydrates of the plants. Additionally, at locality level, silt-clay fraction, organic matter, pH and light intensity incident on the sea bottom were measured to evaluate the environmental conditions. Covering of P. oceanica was significantly lower at the impacted localities while amount of dead "matte" was higher. Leaf production of horizontal rhizomes (14.6 ± 1.11 vs 19.47 ± 1.45 leaves y -1), net total rhizomes recruitment (2.33 ± 0.17 vs 4.3 ± 0.33 branches y -1) and starch concentration (43.625 ± 0.67 vs 54.45 ± 0.74 mg per g of rhizome) at impacted meadows were significantly lower than controls. Leaf features, epiphytes biomass, colonization, elongation and horizontal and vertical rhizome production did not show significant differences. Sediments at impacted localities contained higher silt-clay fraction and higher organic matter load while pH was lower. Light intensity on the sea bottom measured at all localities was over the minimum light requirements estimated for P. oceanica. Our results show that the press impact produced by beach replenishment was enduring in the time slowing natural recovery by 45%. This impact may be related with changes in the sediment features.

  15. Scrub-shrub bird habitat associations at multiple spatial scales in beaver meadows in Massachusetts

    USGS Publications Warehouse

    Chandler, R.B.; King, D.I.; DeStefano, S.

    2009-01-01

    Most scrub-shrub bird species are declining in the northeastern United States, and these declines are largely attributed to regional declines in habitat availability. American Beaver (Castor canadensis; hereafter "beaver") populations have been increasing in the Northeast in recent decades, and beavers create scrub-shrub habitat through their dam-building and foraging activities. Few systematic studies have been conducted on the value of beaver-modified habitats for scrub-shrub birds, and these data are important for understanding habitat selection of scrub-shrub birds as well as for assessing regional habitat availability for these species. We conducted surveys in 37 beaver meadows in a 2,800-km2 study area in western Massachusetts during 2005 and 2006 to determine the extent to which these beaver-modified habitats are used by scrub-shrub birds, as well as the characteristics of beaver meadows most closely related to bird use. We modeled bird abundance in relation to microhabitat-, patch-, and landscape-context variables while adjusting for survey-specific covariates affecting detectability using N-mixture models. We found that scrub-shrub birds of regional conservation concern occupied these sites and that birds responded differently to microhabitat, patch, and landscape characteristics of beaver meadows. Generally, scrub-shrub birds increased in abundance along a gradient of increasing vegetation complexity, and three species were positively related to patch size. We conclude that these habitats can potentially play an important role in regional conservation of scrub-shrub birds and recommend that conservation priority be given to larger beaver meadows with diverse vegetation structure and composition. ?? 2009 by The American Ornithologists' Union. All rights reserved.

  16. Importance of molehill disturbances for invasion by Bunias orientalis in meadows and pastures

    NASA Astrophysics Data System (ADS)

    Kiełtyk, Piotr; Mirek, Zbigniew

    2015-04-01

    Small-scale soil disturbances by fossorial animals can change physical and biotic conditions in disturbed patches and influence spatial and temporal dynamics, and the composition of plant communities. They create regeneration niches and colonization openings for native plants and, according to the intermediate disturbance hypothesis, they are expected to increase plant community diversity. However, it also has been reported that increased disturbance resource availability and decreased competition with native species may result in the invasion of communities by alien plant species, as predicted by the fluctuating resources theory of invasibility. In this study, we investigated the importance of European mole disturbances for the invasion of semi-natural fresh meadows and pastures by the alien plant, Bunias orientalis, which has mainly spread throughout Central Europe on anthropogenically disturbed sites. We hypothesized that the invader, being particularly well adapted to anthropogenic disturbances, enters into dense vegetation of meadows and pastures mainly on mole mounds. To assess the seedling recruitment of B. orientalis in relation to disturbance, we counted the number of seedlings that emerged on molehills and control plots in meadows and pastures. The establishment of juvenile (0-1 year) rosette plants on and off molehills was surveyed on 5 × 5 m plots. In accordance with our hypothesis, mole disturbances were found to serve as a gateway for B. orientalis by which the invader may colonize semi-natural grasslands. The seedlings of the species emerged almost solely on molehills and the young rosettes were established predominantly on mole mounds. Although the seedling density did not differ significantly between the meadows and pastures, the number of established plants in the pastures was considerably higher. We suggest that the invasion by B. orientalis in pastures may be facilitated by vegetative regeneration following root fragmentation by sheep pasturing.

  17. Survivorship of meadow voles, Microtus pennsylvanicus, from sewage sludge-treated fields

    SciTech Connect

    Maly, M.S.

    1984-06-01

    A long-term field study was begun in 1977 at Miami University to evaluate the effects of land application of sewage sludge on experimental old-field communities. The effects of sludge application on toxic metal concentrations in meadow vole (Microtus pennsylvanicus) organs during the first two years of the study have been reported. During the first two years of sludge application, no detrimental effects were observed in vole survivorship as a result of sludge treatment.

  18. Impacts of management practices on soil organic carbon in degraded alpine meadows on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Chang, X. F.; Wang, S. P.; Zhu, X. X.; Cui, S. J.; Luo, C. Y.; Zhang, Z. H.; Wilkes, A.

    2014-01-01

    Grassland soil organic carbon (SOC) is sensitive to anthropogenic activities. Increased anthropogenic disturbance related to overgrazing has led to widespread alpine grassland degradation on the Tibetan Plateau. The degraded grasslands are considered to have great potential for carbon sequestration after adoption of improved management practices. Here, we calibrated and employed the Century model to investigate the effects of overgrazing and improved managements on the SOC dynamics in alpine meadows. We calibrated Century model against plant productivity at Haibei Research Station. SOC stocks for validation were obtained in 2009-2010 from degraded alpine meadows in two communes. We found that Century model can successfully capture grassland SOC changes. Overall, our simulation suggests that degraded alpine meadow SOC significantly increased with the advent of restoration managements from 2011 to 2030. Carbon sequestration rates ranged between 0.04 Mg C ha-1 yr-1 in lightly degraded winter grasslands and 2.0 Mg C ha-1 yr-1 in moderately degraded summer grasslands. Our modeling work also predicts that improve management in Tibetan degraded grasslands will contribute to an annual carbon sink of 0.022-0.059 Pg C yr-1. These results imply that restoration of degraded grasslands in Tibetan Plateau has great potential for soil carbon sequestration to mitigate greenhouse gases.

  19. Impacts of management practices on soil organic carbon in degraded alpine meadows on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Chang, X. F.; Zhu, X. X.; Wang, S. P.; Cui, S. J.; Luo, C. Y.; Zhang, Z. H.; Wilkes, A.

    2014-07-01

    Grassland soil organic carbon (SOC) is sensitive to anthropogenic activities. Increased anthropogenic disturbance related to overgrazing has led to widespread alpine grassland degradation on the Tibetan Plateau. The degraded grasslands are considered to have great potential for carbon sequestration after adoption of improved management practices. Here, we calibrated and employed the Century model to investigate the effects of overgrazing and improved managements on the SOC dynamics in alpine meadows. We calibrated the Century model against plant productivity at the Haibei Research Station. SOC stocks for validation were obtained in 2009-2010 from degraded alpine meadows in two communes. We found that Century model can successfully capture grassland SOC changes. Overall, our simulation suggests that degraded alpine meadow SOC significantly increased with the advent of restoration management from 2011 to 2030. Carbon sequestration rates ranged between 0.04 Mg C ha-1 yr-1 in lightly degraded winter grazing grasslands and 2.0 Mg C ha-1 yr-1 in moderately degraded summer grazing grasslands. Our modelling work also predicts that improve management in degraded Tibetan grasslands will contribute to an annual carbon sink of 0.022-0.059 Pg C yr-1. These results imply that restoration of degraded grasslands in the Tibetan Plateau has great potential for soil carbon sequestration to mitigate greenhouse gases.

  20. Climate, geography, and tree establishment in subalpine meadows of the Olympic Mountains, Washington, USA

    USGS Publications Warehouse

    Woodward, Andrea; Schreiner, Edward G.; Silsbee, D.G.

    1995-01-01

    Noticeable changes in vegetation distribution have occurred in the Pacific Northwest during the last century as trees have established in some subalpine meadows. To study the relationship of this process to climate, recently established trees were aged in six subalpine meadows in the Olympic Mountains, Washington. The sites represent three points along a steep precipitation gradient. Subalpine fir (Abies lasiocarpa) has been establishing at the dry end of the gradient, mountain hemlock (Tsuga mertensiana) at the wet end, and both species in the center. Establishment patterns were compared with deviations from the century-long average for these weather variables: winter precipitation, Palmer Drought Severity Index, and winter, October, and May temperatures. Results show that establishment occurred in dry areas when weather conditions were wetter than average, and in wet areas under drier than average conditions. Establishment at central sites did not show consistent relationships with climate. If future climatic conditions continue to warm, establishment of subalpine fir in subalpine meadows in dry areas may cease and mountain hemlock may resume in wet areas.

  1. Compositional and functional stability of aerobic methane consuming communities in drained and rewetted peat meadows.

    PubMed

    Krause, Sascha; Niklaus, Pascal A; Badwan Morcillo, Sara; Meima Franke, Marion; Lüke, Claudia; Reim, Andreas; Bodelier, Paul L E

    2015-11-01

    The restoration of peatlands is an important strategy to counteract subsidence and loss of biodiversity. However, responses of important microbial soil processes are poorly understood. We assessed functioning, diversity and spatial organization of methanotrophic communities in drained and rewetted peat meadows with different water table management and agricultural practice. Results show that the methanotrophic diversity was similar between drained and rewetted sites with a remarkable dominance of the genus Methylocystis. Enzyme kinetics depicted no major differences, indicating flexibility in the methane (CH4) concentrations that can be used by the methanotrophic community. Short-term flooding led to temporary elevated CH4 emission but to neither major changes in abundances of methane-oxidizing bacteria (MOB) nor major changes in CH4 consumption kinetics in drained agriculturally used peat meadows. Radiolabeling and autoradiographic imaging of intact soil cores revealed a markedly different spatial arrangement of the CH4 consuming zone in cores exposed to near-atmospheric and elevated CH4. The observed spatial patterns of CH4 consumption in drained peat meadows with and without short-term flooding highlighted the spatial complexity and responsiveness of the CH4 consuming zone upon environmental change. The methanotrophic microbial community is not generally altered and harbors MOB that can cover a large range of CH4 concentrations offered due to water-table fluctuations, effectively mitigating CH4 emissions.

  2. Estimated ground-water discharge by evapotranspiration, Ash Meadows Area, Nye County, Nevada, 1994

    SciTech Connect

    Nichols, W.D.; Laczniak, R.J.; DeMeo, G.A.; Rapp, T.R.

    1997-05-01

    Ground water discharges from the regional ground-water flow system that underlies the eastern part of the Nevada Test Site through numerous springs and seeps in the Ash Meadows National Wildlife Refuge in southern Nevada. The total spring discharge was estimated to be about 17,000 acre-feet per year by earlier studies. Previous studies estimated that about 10,500 acre-feet of this discharge was lost to evapotranspiration. The present study was undertaken to develop a more rigorous approach to estimating ground-water discharge in the Ash Meadows area. Part of the study involves detailed field investigation of evapotranspiration. Data collection began in early 1994. The results of the first year of study provide a basis for making preliminary estimates of ground-water discharge by evapotranspiration. An estimated 13,100 acre-feet of ground water was evapotranspired from about 6,800 acres of marsh and salt-grass. Additional 3,500 acre-feet may have been transpired from the open water and from about 1,460 acres of other areas of Ash Meadows in which field studies have not yet been made.

  3. The melliferous potential of forest and meadow plant communities on Mount Tara (Serbia).

    PubMed

    Jarić, Snežana; Mačukanović-Jocić, Marina; Mitrović, Miroslava; Pavlović, Pavle

    2013-08-01

    The apiflora of 34 forest and meadow plant communities in Tara National Park was studied with the aim of assessing their melliferous potential and their contribution to bee pasture during the vegetation period. The melliferous plants were analyzed individually from the aspect of their flowering phenology, abundance, and the intensity of nectar and pollen production, as well as the production of honeydew. The melliferous potential of each investigated plant community was theoretically assessed on the basis of the coenotic coefficient of melliferousness incorporating a phytocoenotic analysis, the coenotic coefficients of nectar and pollen production, and the percentage of melliferous species in relation to the total number of species that characterize the association. The highest percentage of the melliferous species was noted in the meadow association Petasitetum hybridi (70%) and the forest association Piceetum-Abietis serpentinicum (63.6%). The highest values of the coenotic coefficient of melliferousness were established for the forest association Querco-Carpinetum iliricum, and the meadow association Rhinantho-Cynosuretum cristati. Trees notable for their honeydew production in good quantities were Pinus nigra Arnold, Picea sp. Fagus sylvatica Linnaeus, Populus tremula Linnaeus, and Quercus cerris Linnaeus. Because, the vegetation in the study area is forest dominated, forest bee pasture including early flowering herbaceous and woody plants, is of the greatest significance for the honey bee, both in the early spring because of pollen and nectar production, and in the autumn as a source of honeydew. PMID:23905735

  4. Leaf unfolding of Tibetan alpine meadows captures the arrival of monsoon rainfall

    PubMed Central

    Li, Ruicheng; Luo, Tianxiang; Mölg, Thomas; Zhao, Jingxue; Li, Xiang; Cui, Xiaoyong; Du, Mingyuan; Tang, Yanhong

    2016-01-01

    The alpine meadow on the Tibetan Plateau is the highest and largest pasture in the world, and its formation and distribution are mainly controlled by Indian summer monsoon effects. However, little is known about how monsoon-related cues may trigger spring phenology of the vast alpine vegetation. Based on the 7-year observations with fenced and transplanted experiments across lower to upper limits of Kobresia meadows in the central plateau (4400–5200 m), we found that leaf unfolding dates of dominant sedge and grass species synchronized with monsoon onset, regardless of air temperature. We also found similar patterns in a 22-year data set from the northeast plateau. In the monsoon-related cues for leaf unfolding, the arrival of monsoon rainfall is crucial, while seasonal air temperatures are already continuously above 0 °C. In contrast, the early-emerging cushion species generally leafed out earlier in warmer years regardless of precipitation. Our data provide evidence that leaf unfolding of dominant species in the alpine meadows senses the arrival of monsoon-season rainfall. These findings also provide a basis for interpreting the spatially variable greening responses to warming detected in the world’s highest pasture, and suggest a phenological strategy for avoiding damages of pre-monsoon drought and frost to alpine plants. PMID:26856260

  5. Pilot Application of 3d Underwater Imaging Techniques for Mapping Posidonia Oceanica (L.) Delile Meadows

    NASA Astrophysics Data System (ADS)

    Rende, F. S.; Irving, A. D.; Lagudi, A.; Bruno, F.; Scalise, S.; Cappa, P.; Montefalcone, M.; Bacci, T.; Penna, M.; Trabucco, B.; Di Mento, R.; Cicero, A. M.

    2015-04-01

    Seagrass communities are considered one of the most productive and complex marine ecosystems. Seagrasses belong to a small group of 66 species that can form extensive meadows in all coastal areas of our planet. Posidonia oceanica beds are the most characteristic ecosystem of the Mediterranean Sea, and should be constantly monitored, preserved and maintained, as specified by EU Habitats Directive for priority habitats. Underwater 3D imaging by means of still or video cameras can allow a detailed analysis of the temporal evolution of these meadows, but also of the seafloor morphology and integrity. Video-photographic devices and open source software for acquiring and managing 3D optical data rapidly became more and more effective and economically viable, making underwater 3D mapping an easier task to carry out. 3D reconstruction of the underwater scene can be obtained with photogrammetric techniques that require just one or more digital cameras, also in stereo configuration. In this work we present the preliminary results of a pilot 3D mapping project applied to the P. oceanica meadow in the Marine Protected Area of Capo Rizzuto (KR, Calabria Region - Italy).

  6. Meadow fragmentation and reproductive output of the SE Asian seagrass Enhalus acoroides [rapid communication

    NASA Astrophysics Data System (ADS)

    Vermaat, Jan E.; Rollon, Rene N.; Lacap, Cristina Day A.; Billot, Claire; Alberto, Filipe; Nacorda, Hildie M. E.; Wiegman, Frank; Terrados, Jorge

    2004-11-01

    Flower and fruit production of the abundant, tall, long-lived, dioecious, surface-pollinating seagrass species Enhalus acoroides (L.) Royle were estimated at seven sites in the reef flats off Bolinao (NW Luzon, The Philippines) featuring different fragmentation of the seagrass meadows. Fragmentation of the seagrass meadow was quantified as cover of E. acoroides and all seagrass species present in 20×20 m plots. E. acoroides and overall seagrass cover were correlated positively. The proportion of female flowers of E. acoroides that developed a fruit increased sharply as overall seagrass cover was around 50%. Apparent sex ratio bore no relationship with overall seagrass cover. This threshold-type of relationship suggests that fragmentation of seagrass meadows can have a major effect on the reproductive output of this species. A possible mechanism underlying these results would be a non-linear increase of the efficiency of trapping the surface-dispersed pollen with increasing seagrass canopy density. This provides the first evidence based on real data that fragmentation can affect the population dynamics of seagrass species.

  7. AxIOM: Amphipod crustaceans from insular Posidonia oceanica seagrass meadows

    PubMed Central

    Heughebaert, André; Lepoint, Gilles

    2016-01-01

    Abstract Background The Neptune grass, Posidonia oceanica (L.) Delile, 1813, is the most widespread seagrass of the Mediterranean Sea. This foundation species forms large meadows that, through habitat and trophic services, act as biodiversity hotspots. In Neptune grass meadows, amphipod crustaceans are one of the dominant groups of vagile invertebrates, forming an abundant and diverse taxocenosis. They are key ecological components of the complex, pivotal, yet critically endangered Neptune grass ecosystems. Nevertheless, comprehensive qualitative and quantitative data about amphipod fauna found in Mediterranean Neptune grass meadows remain scarce, especially in insular locations. New information Here, we provide in-depth metadata about AxIOM, a sample-based dataset published on the GBIF portal. AxIOM is based on an extensive and spatially hierarchized sampling design with multiple years, seasons, day periods, and methods. Samples were taken along the coasts of Calvi Bay (Corsica, France) and of the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, Italy). In total, AxIOM contains 187 samples documenting occurrence (1775 records) and abundance (10720 specimens) of amphipod crustaceans belonging to 72 species spanning 29 families. The dataset is available at http://ipt.biodiversity.be/resource?r=axiom. PMID:27660521

  8. AxIOM: Amphipod crustaceans from insular Posidonia oceanica seagrass meadows

    PubMed Central

    Heughebaert, André; Lepoint, Gilles

    2016-01-01

    Abstract Background The Neptune grass, Posidonia oceanica (L.) Delile, 1813, is the most widespread seagrass of the Mediterranean Sea. This foundation species forms large meadows that, through habitat and trophic services, act as biodiversity hotspots. In Neptune grass meadows, amphipod crustaceans are one of the dominant groups of vagile invertebrates, forming an abundant and diverse taxocenosis. They are key ecological components of the complex, pivotal, yet critically endangered Neptune grass ecosystems. Nevertheless, comprehensive qualitative and quantitative data about amphipod fauna found in Mediterranean Neptune grass meadows remain scarce, especially in insular locations. New information Here, we provide in-depth metadata about AxIOM, a sample-based dataset published on the GBIF portal. AxIOM is based on an extensive and spatially hierarchized sampling design with multiple years, seasons, day periods, and methods. Samples were taken along the coasts of Calvi Bay (Corsica, France) and of the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, Italy). In total, AxIOM contains 187 samples documenting occurrence (1775 records) and abundance (10720 specimens) of amphipod crustaceans belonging to 72 species spanning 29 families. The dataset is available at http://ipt.biodiversity.be/resource?r=axiom.

  9. Response of ecosystem respiration to experimental warming and clipping in Tibetan alpine meadow at three elevations

    NASA Astrophysics Data System (ADS)

    Fu, G.; Zhang, Y.-J.; Zhang, X.-Z.; Shi, P.-L.; Zhou, Y.-T.; Li, Y.-L.; Shen, Z.-X.

    2013-08-01

    This study aims to understand the response of ecosystem respiration (Reco) to warming and clipping in the alpine meadow of Tibet. A field warming experiment using open top chambers was conducted in three alpine meadow sites at elevation 4313 m, 4513 m and 4693 m on the Tibetan Plateau since July 2008. Clipping was conducted three times a year since 2009. Reco was measured from June to September in 2010-2012. For most cases, the seasonal variation of Reco was mainly affected by soil water content rather than soil and air temperature, especially under warmer environment. Experimental warming tended to decrease seasonal average Reco by 21.6% and 10.9% at elevation 4313 m and 4513 m, respectively, but significantly increased seasonal average Reco by 11.3% at elevation 4693 m. The different responses of Reco to experimental warming could be mainly dependent on temperature and water availability condition. Clipping decreased seasonal average Reco by 6.9%, 36.9% and 31.6% at elevation 4313 m, 4513 m and 4693 m. The consistent declines caused by clipping may be mainly attributed to clipping-induced decline in aboveground biomass. Our findings suggested that the response of Reco to warming differed among the alpine meadow and was regulated by soil water content on the Tibetan Plateau.

  10. Effect of irrigation pumping on desert pupfish habitats in the Ash Meadows, Nye County, Nevada

    USGS Publications Warehouse

    Dudley, William W.; Larson, J.D.

    1976-01-01

    The Ash Meadows area, at the southern tip of the Amargosa Desert in southern Nevada, discharges ground water collected over several thousand square miles of a regional flow system developed in Paleozoic carbonate rocks. Water moves westward across fault contacts from the bedrock into poorly interconnected gravel, sand, and terrestrial-limestone aquifers in the upper few hundred feet of the basin sediments at Ash Meadows. A small pool in Devils Hole, which is a collapse depression in Cambrian limestone, and numerous springs in the adjacent desert valley contain rare fish species of the genus Cyprinodon, faunal remnants of Pleistocene lakes. The Devils Hole pupfish, C. diabolis, is the most endangered of the several surviving species that have evolved since the post-pluvial isolation of their ancestors. This population feeds and reproduces on a slightly submerged rock ledge. Recent irrigation pumping has nearly exposed this ledge. Correlation of pumping histories with the stage in Devils Hole allows identification of several wells that affect the pool level most severly. Some springs that are habitats for other species of Cyprinodon have reduced discharge because of pumping. Hydraulic testing, long-term water-level monitoring, water quality, and geologic evidence aid in defining the principal flow paths and hydraulic interconnections in the Ash Meadows area. (Woodard-USGS)

  11. Response of Soil Respiration to Grazing in an Alpine Meadow at Three Elevations in Tibet

    PubMed Central

    Fu, Gang; Zhang, Xianzhou; Yu, Chengqun; Shi, Peili; Zhou, Yuting; Li, Yunlong; Yang, Pengwan; Shen, Zhenxi

    2014-01-01

    Alpine meadows are one major type of pastureland on the Tibetan Plateau. However, few studies have evaluated the response of soil respiration (Rs) to grazing along an elevation gradient in an alpine meadow on the Tibetan Plateau. Here three fenced enclosures were established in an alpine meadow at three elevations (i.e., 4313 m, 4513 m, and 4693 m) in July 2008. We measured Rs inside and outside the three fenced enclosures in July–September, 2010-2011. Topsoil (0–20 cm) samples were gathered in July, August, and September, 2011. There were no significant differences for Rs, dissolved organic C (DOC), and belowground root biomass (BGB) between the grazed and ungrazed soils. Soil respiration was positively correlated with soil organic C (SOC), microbial biomass (MBC), DOC, and BGB. In addition, both Rs and BGB increased with total N (TN), the ratio of SOC to TN, ammonium N (NH4+-N), and the ratio of NH4+-N to nitrate N. Our findings suggested that the negligible response of Rs to grazing could be directly attributed to that of respiration substrate and that soil N may indirectly affect Rs by its effect on BGB. PMID:24790558

  12. Biophysical regulation of carbon fluxes over an alpine meadow ecosystem in the eastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Shaoying; Zhang, Yu; Lü, Shihua; Su, Peixi; Shang, Lunyu; Li, Zhaoguo

    2016-06-01

    The eddy covariance method was used to measure net ecosystem CO2 exchange (NEE) between atmosphere and an alpine meadow ecosystem in the eastern Tibetan Plateau of China in 2010. Our results show that photosynthesis was reduced under low air temperature ( T a), high vapor pressure deficit (VPD), and medium soil water content (SWC) conditions, when compared to that under other T a (i.e., medium and high), VPD (i.e., low and medium), and SWC (i.e., low and high) conditions. The apparent temperature sensitivity of ecosystem respiration ( Q 10) declined with progressing phenology during the growing season and decreased with an increase of soil temperature ( T s) during the non-growing season. Increased ecosystem respiration ( R eco) was measured during spring soil thawing. By the path analysis, T a, T s, and VPD were the main control factors of CO2 exchange at 30-min scale in this alpine meadow. Integrated NEE, gross primary production (GPP), and R eco over the measured year were -156.4, 1164.3, and 1007.9 g C m-2, respectively. Zoige alpine meadow was a medium carbon sink based on published data for grassland ecosystems.

  13. Seasonal variability of suprabenthic crustaceans associated with Cymodocea nodosa seagrass meadows off Gran Canaria (eastern Atlantic)

    NASA Astrophysics Data System (ADS)

    Herrera, A.; Landeira, J. M.; Tuya, F.; Packard, T.; Espino, F.; Gómez, M.

    2014-10-01

    Seagrass meadows are important ecosystems on shallow coastal waters, maintaining a high diversity of species. Mysids are the dominant taxa of suprabenthic organisms associated with seagrass meadows in temperate coastal waters, where they are an important food resource for the coastal fishes. Five meadows of Cymodocea nodosa were sampled off the east and west of Gran Canaria Island in spring and autumn 2011 to describe associated suprabenthos and to determine seasonal changes in the abundance of suprabenthos assemblages. Mysids, decapods and amphipods made up 95% of total suprabenthos abundance, which was more abundant in spring (May) than in autumn (November). A total of 29 species were identified, 12 amphipod, 11 decapod and 6 mysid species. The mysid Leptomysis lingvura did not show seasonal differences, while Anchialina agilis showed greater abundance in May at all localities. For the other mysid species, abundances were higher in May than November, although significant differences varied among localities. The dominant amphipod, Apherusa vexatrix, and the dominant decapod, Hippolyte spp., also showed significant differences in density between seasons, being higher in May at all localities. From these results, we conclude that there is an overlap between the natural life cycle of the seagrass C. nodosa and associated suprabenthos.

  14. EVALUATION OF LODGE POLE PINE TREE REMOVAL ON THE STORAGE POTENTIAL OF A SHALLOW AQUIFER IN A MOUNTAIN MEADOW

    NASA Astrophysics Data System (ADS)

    Lesh, M.; Cornwell, K.; Koler, T.

    2009-12-01

    During a time of ever-increasing awareness of the importance of well functioning stream and associated riparian areas, forest managers face a wide range of restoration alternatives. Many of these systems occur at higher elevations, often in non-forested alpine or in less productive forests and woodlands where mountain meadows are commonly found. A common theme of these restoration efforts in western North America over the past 20 years has been to re-establish degraded systems to significant sources of groundwater storage in an effort to preserve and replenish water resources. Historically, restorations efforts in meadow systems have commonly been focused on quantifying the water supply impacts of stream and river degradation due to unchecked erosion. However, other restoration alternatives may be available to forest managers when degradation is shown to not be correlated to stream and river function, but rather vegetation growth patterns within the system. This study evaluates the physical characteristics and predicted hydrologic function in response to the removal of Pinus contorta (commonly referred to as lodge pole pine trees) of Timothy Meadow located in northern Sierra Nevada, Eldorado County, California. Forest Service managers in the Eldorado National forest are presently considering the removal of lodge pole pine trees that have encroached on the meadow in an effort to increase the amount of groundwater storage in the meadow sediments. Previous work in vegetation management as it relates to storage has been conducted in other parts of the country with differing results following tree harvesting. The results of these studies would appear to indicate that the effectiveness of vegetation removal correlates to the hydrologic functionality of the meadow or wetlands prior to removal. Timothy Meadow offers a unique opportunity to study the predicted response of a hydrologically functional meadow to simulated removal of lodge pole pine trees. The physical

  15. Habitat-specific responses of leaf traits to soil water conditions in species from a novel alpine swamp meadow community.

    PubMed

    Li, Honglin; Nicotra, Adrienne B; Xu, Danghui; Du, Guozhen

    2015-01-01

    Species originally from alpine wetland and alpine meadow communities now coexist in a novel 'alpine swamp meadow' community as a consequence of wetland drying in the eastern Tibetan Plateau. Considering the projected increase in the fluctuation of water supply from precipitation during the growing season in this area in the future, it is important to investigate the responses of the species that make up this new community to soil water availability. Using a transplant experimental design, we compared the response of leaf traits and growth to different water conditions for species grouped according to their original habitat of wetland or meadow. Twelve perennial herbaceous species, which form an alpine swamp meadow community in Maqu County in the eastern Tibetan Plateau, were used in this study and subjected to two water treatments, namely waterlogged and dry-down. Overall, significant differences in leaf production in response to soil water availability were found for these two groups, indicating strongly different effects of water availability on their growth. Furthermore, the meadow group had lower specific leaf area, leaf area and relative leaf water content, but thicker leaves than those of the wetland group, indicating significant habitat-specific differences in leaf morphology. Regarding physiological traits, the wetland group had significantly higher photosynthetic rates in inundated conditions, whereas for the meadow group the photosynthetic rate was greatest in cyclically dry conditions. Likewise, a similar pattern was observed for stomatal conductance; however, both groups achieved higher instantaneous water use efficiency during the dry-down treatment. The results of this study indicate that the composition of the alpine swamp meadow could be sensitive to changes in precipitation and might be changed substantially by future declines in water supply, as predicted by global climate change models for this region. This potential for compositional change of

  16. Quantifying seasonal volume of groundwater in high elevation meadows: Implications for complex aquifer geometry in a changing climate

    NASA Astrophysics Data System (ADS)

    Ciruzzi, Dominick M.

    The hydrologic impacts of rising global temperatures are severe and imminent particularly in snow-dominated regions. In the western United States, high elevation meadows are among the ecosystems highly sensitive to climate change. High elevation meadows are groundwater dependent ecosystems and rely on seasonal snowpack melt in order to support ecologic function and baseflow to streams. This stream flow in turn supplies an estimated 2.6 million San Francisco residents with water. Once the snow melts and recharges the aquifer, groundwater supports vegetation separate from the surrounding hillslopes, which promotes important ecologic functions like flood regulation and nutrient cycling. Groundwater also supports baseflow to perennial rivers late into the summer months transferring this snowmelt to downstream ecologic and human communities. By 2100 snowpack accumulation in the Sierra Nevada is expected to decrease by ~40-90% due to near-surface temperature rise. Though precipitation intensity is not expected to change, a decrease in snowpack will change the timing and magnitude of groundwater recharge necessary to sustain high elevation meadows. An additional climate-driven shift and decrease in peak stream flow to early spring away from summer when demand is highest puts into question ecosystem survivability and water supply to downstream users. Here, a new quantitative framework is presented to lay the foundation for the widespread identification of vulnerabilities in high elevation meadows due to climate change. This research proposed and tested a new conceptual model for the volume of groundwater stored in high elevation meadows similar to that of a reservoir with active and dead storage. The seasonal fluctuations in active storage, which is defined as the volume of groundwater able to exchange between the aquifer, streams, and vegetation, are thought to be highly sensitive to aquifer parameters, such as bedrock geometry, meadow gradient, and hydraulic conductivity

  17. Phenols content and 2-D electrophoresis protein pattern: a promising tool to monitor Posidonia meadows health state

    PubMed Central

    Migliore, Luciana; Rotini, Alice; Randazzo, Davide; Albanese, Nadia N; Giallongo, Agata

    2007-01-01

    Background The endemic seagrass Posidonia oceanica (L.) Delile colonizes soft bottoms producing highly productive meadows that play a crucial role in coastal ecosystems dynamics. Human activities and natural events are responsible for a widespread meadows regression; to date the identification of "diagnostic" tools to monitor conservation status is a critical issue. In this study the feasibility of a novel tool to evaluate ecological impacts on Posidonia meadows has been tested. Quantification of a putative stress indicator, i.e. phenols content, has been coupled to 2-D electrophoretic protein analysis of rhizome samples. Results The overall expression pattern from Posidonia rhizome was determined using a preliminary proteomic approach, 437 protein spots were characterized by pI and molecular weight. We found that protein expression differs in samples belonging to sites with high or low phenols: 22 unique protein spots are peculiar of "low phenols" and 27 other spots characterize "high phenols" samples. Conclusion Posidonia showed phenols variations within the meadow, that probably reflect the heterogeneity of environmental pressures. In addition, comparison of the 2-D electrophoresis patterns allowed to highlight qualitative protein expression differences in response to these pressures. These differences may account for changes in metabolic/physiological pathways as adaptation to stress. A combined approach, based on phenols content determination and 2-D electrophoresis protein pattern, seems a promising tool to monitor Posidonia meadows health state. PMID:17663776

  18. Information to support to monitoring and habitat restoration on Ash Meadows National Wildlife Refuge

    USGS Publications Warehouse

    Scoppettone, G. Gary

    2013-01-01

    The Ash Meadows National Wildlife Refuge staff focuses on improving habitat for the highest incidence of endemic species for an area of its size in the continental United States. Attempts are being made to restore habitat to some semblance of its pre-anthropogenic undisturbed condition, and to provide habitat conditions to which native plant and animal species have evolved. Unfortunately, restoring the Ash Meadows’ Oases to its pre-anthropogenic undisturbed condition is almost impossible. First, there are constraints on water manipulation because there are private holdings within the refuge boundary; second, there has been at least one species extinction—the Ash Meadows pool fish (Empetrichthys merriami). It is also quite possible that thermal endemic invertebrate species were lost before ever being described. Perhaps the primary obstacle to restoring Ash Meadows to its pre-anthropogenic undisturbed conditions is the presence of invasive species. However, invasive species, such as red swamp crayfish (Procambarus clarki) and western mosquitofish (Gambusia affinis), are a primary driving force in restoring Ash Meadows’ spring systems, because under certain habitat conditions they can all but replace native species. Returning Ash Meadows’ physical landscape to some semblance of its pre-anthropogenic undisturbed condition through natural processes may take decades. Meanwhile, the natural dissolution of concrete and earthen irrigation channels threatens to allow cattail marshes to flourish instead of spring-brooks immediately downstream of spring discharge. This successional stage favors non-native crayfish and mosquitofish over the native Amargosa pupfish (Cyprinodon nevadensis). Thus, restoration is needed to control non-natives and to promote native species, and without such intervention the probability of native fish reduction or loss, is anticipated. The four studies in this report are intended to provide information for restoring native fish habitat and

  19. Soil Fauna Affects Dissolved Carbon and Nitrogen in Foliar Litter in Alpine Forest and Alpine Meadow

    PubMed Central

    Liao, Shu; Yang, Wanqin; Tan, Yu; Peng, Yan; Li, Jun; Tan, Bo; Wu, Fuzhong

    2015-01-01

    Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) are generally considered important active biogeochemical pools of total carbon and nitrogen. Many studies have documented the contributions of soil fauna to litter decomposition, but the effects of the soil fauna on labile substances (i.e., DOC and TDN) in litter during early decomposition are not completely clear. Therefore, a field litterbag experiment was carried out from 13th November 2013 to 23rd October 2014 in an alpine forest and an alpine meadow located on the eastern Tibetan Plateau. Litterbags with different mesh sizes were used to provide access to or prohibit the access of the soil fauna, and the concentrations of DOC and TDN in the foliar litter were measured during the winter (the onset of freezing, deep freezing and thawing stage) and the growing season (early and late). After one year of field incubation, the concentration of DOC in the litter significantly decreased, whereas the TDN concentration in the litter increased. Similar dynamic patterns were detected under the effects of the soil fauna on both DOC and TDN in the litter between the alpine forest and the alpine meadow. The soil fauna showed greater positive effects on decreasing DOC concentration in the litter in the winter than in the growing season. In contrast, the dynamics of TND in the litter were related to seasonal changes in environmental factors, rather than the soil fauna. In addition, the soil fauna promoted a decrease in litter DOC/TDN ratio in both the alpine forest and the alpine meadow throughout the first year of decomposition, except for in the late growing season. These results suggest that the soil fauna can promote decreases in DOC and TDN concentrations in litter, contributing to early litter decomposition in these cold biomes. PMID:26406249

  20. Impact of alpine meadow degradation on soil hydraulic properties over the Qinghai-Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zeng, Chen; Zhang, Fan

    2015-04-01

    Alpine meadow is one of widespread vegetation types of the Qinghai-Tibetan Plateau. It is undergoing degradation under the background of global climate change, human activities and overgrazing. Soil moisture is important to alpine meadow ecology for its water and energy transfer processes, therefore soil hydraulic properties become key parameters for local eco-hydrological processes studies. However, little research focus on the changes and it's mechanisms of soil hydraulic properties during the degradation processes. In this study, soil basic and hydraulic properties at 0-10 cm and 40-50 cm soil layer depths under different degraded alpine meadow were analyzed. Pearson correlations were adopted to study the relationships among the investigated factors and principal component analysis was performed to identify the dominant factor. Results show that with increasing degree of degradation, soil sand content increased while soil saturated hydraulic conductivity (Ks) as well as soil clay content, soil porosity decreased in the 0-10 cm soil layers, and organic matter and root gravimetric density decreased in both the 0-10 cm and 40-50 cm soil layers. For soil unsaturated hydraulic conductivity, it reduced more slowly with decreasing pressure head under degraded conditions than non-degraded conditions. However, soil moisture showed no significant changes with increasing degradation. Soil Ks was significantly correlated (P = 0.01) with bulk density, soil porosity, soil organic matter and root gravimetric density. Among these, soil porosity is the dominant factor explaining about 90% of the variability in total infiltration flow. Under non-degraded conditions, the infiltration flow principally depended on the presence of macropores. With increasing degree of degradation, soil macropores quickly changed to mesopores or micropores. The proportion of total infiltration flow through macropores and mesopores significantly decreased with the most substantial decrease observed for

  1. Biophysical Regulation of Carbon Fluxes over an Alpine Meadow Ecosystem in the Eastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Shaoying; Zhang, Yu; Lü, Shihua; Shang, Lunyu

    2014-05-01

    We used the eddy covariance method to measure the CO2 exchange between the atmosphere and an alpine meadow ecosystem in the eastern Tibetan Plateau, China in 2010. The photosynthesis was depressed under low air temperature (Ta), high vapor pressure deficit (VPD) and medium soil water content (SWC) conditions. Temperature was the most dominant factor controlling ecosystem photosynthesis in this alpine meadow. Regardless of photosynthetically active radiation (PAR), the relationship between net ecosystem CO2 exchange (NEE) and Ta (VPD) showed positive correlation when Ta (VPD) lower than optimal value 16.5 ° (0.55 kPa), whereas negative correlation when Ta (VPD) higher than this value. The responses of NEE and ecosystem respiration (Reco) to SWC can be described as a quadratic polynomial when SWC lower than the threshold value 32.5%, however, both NEE and Reco were increased linearly when SWC higher than this value. The optimal SWC for maximum NEE and Reco was 24.6 % when SWC lower than 32.5%. The apparent temperature sensitivity of ecosystem respiration (Q10) declined with the phenology progressed during the growing season, and decreased with the increase in soil temperature (Ts) during the non-growing. Peak daily sums of NEE, gross primary production (GPP), and Reco were -5.27, 13.33, and 10.24 g C m-2 d-1, respectively. Integrated NEE, GPP, and Reco over measured year were -156.4, 1164.3 and 1007.9 g C m-2, respectively. The Zoige alpine meadow was a medium carbon sink in grassland ecosystems.

  2. Tropical seagrass meadows modify seawater carbon chemistry: implications for coral reefs impacted by ocean acidification

    NASA Astrophysics Data System (ADS)

    Unsworth, Richard K. F.; Collier, Catherine J.; Henderson, Gideon M.; McKenzie, Len J.

    2012-06-01

    Highly productive tropical seagrasses often live adjacent to or among coral reefs and utilize large amounts of inorganic carbon. In this study, the effect of seagrass productivity on seawater carbonate chemistry and coral calcification was modelled on the basis of an analysis of published data. Published data (11 studies, 64 records) reveal that seagrass meadows in the Indo-Pacific have an 83% chance of being net autotrophic, resulting in an average net sink of 155 gC m-2 yr-1. The capacities for seagrass productivity were analysed using an empirical model to examine the effect on seawater carbonate chemistry. Our analyses indicate that increases in pH of up to 0.38 units, and Ωarag increases of 2.9 are possible in the presence of seagrass meadows (compared to their absence) with the precise values of these increases dependent on water residence time (tidal flushing) and water depth. In shallow water reef environments, Scleractinian coral calcification downstream of seagrass has the potential to be ≈18% greater than in an environment without seagrass. If this potential benefit to reef calcifiers is supported by further study it offers a potential tool in marine park management at a local scale. The applicability of this will depend upon local physical conditions as well as the spatial configuration of habitats, and the factors that influence their productivity. This novel study suggests that, in addition to their importance to fisheries, sediment stabilization and primary production, seagrass meadows may enhance coral reef resilience to future ocean acidification.

  3. Ecosystem respiration and its components from a Carex meadow of Poyang Lake during the drawdown period

    NASA Astrophysics Data System (ADS)

    Hu, Qiwu; Wu, Qin; Yao, Bo; Xu, Xingliang

    2015-01-01

    Little is known about the components of ecosystem respiration from a subtropical littoral wetland with dramatic annual inundation dynamics. In this study, we investigated ecosystem respiration and its components in a Poyang lake Carex meadow during the drawdown periods from May 2009 to June 2011. Both ecosystem respiration and its components showed clear temporal variation pattern, with temperature being the dominant control. Ecosystem respiration ranged from 98.01 to 1359.25 mg CO2 m-2 h-1. Shoot and root respiration contributed approximately 36% and 26% to the ecosystem respiration, respectively, whereas microbial respiration accounted for 38% of the ecosystem respiration. The ratio of total soil respiration to ecosystem respiration varied from 0.45 to 0.90, depending on growing season stages. Their Q10 values ranged from 1.72 to 2.51, with the maximum for shoot respiration and the minimum for microbial respiration. In addition, the Q10 values varied with time and among ecosystem respiratory components and hence could not be treated as a constant. None of the respiration measurements was significantly related to soil moisture, suggesting that soil moisture was not a limiting environmental factor for respiratory activity during the drawdown periods in this meadow. The Carex meadow acted as strong carbon sink during the drawdown periods due to double growing seasons, but the previous summer flood duration could substantially alter carbon sink intensity in the following drawdown period. The total carbon sink of the littoral zone of Poyang Lake during drawdown periods was estimated to be 0.17-0.59 Tg C yr-1.

  4. Mineral resources of the Sacatar Meadows Wilderness study Area, Tulare and Inyo counties, California

    SciTech Connect

    Diggles, M.F.; Frisken, J.G.; Griscom, A.; Kuizon, L.

    1988-01-01

    At the request of the US Bureau of Land Management, approximately 11,447 acres of the Sacatar Meadows Wilderness Study Area were evaluated for mineral resources (known) and mineral resource potential (undiscovered). No mineral resources were identified. There are five areas of low mineral resource potential (tungsten and molybdenum) in and near the study area. The host rocks for these minerals are Mesozoic-age granitic rocks of the Sierra Nevada Batholith and calcareous metamorphic roof-pendant rocks. The area has no geothermal energy, energy mineral, or oil and gas resource potential.

  5. Cholinesterase inhibition in meadow voles Microtus pennsylvanicus following field applications of Orthene

    USGS Publications Warehouse

    Jett, D.A.

    1986-01-01

    Brain acetylcholinesterase activity in field-caught meadow voles (Microtus pennsylvanicus) was depressed after a field-spray of Orthene (acephate: acetylphosphoramidothioic acid O,S-dimethyl ester) by as much as 32% in 1982 and 38% in 1983. Short-term recovery was demonstrated and occurred in a time-dependent fashion in 1982. Plasma cholinesterase levels were move variable but also were depressed. Residues were detected in vegetation samples and in the gastrointestinal tracts of exposed voles. Residues in vegetation were diluted or absent 7 to 8 d following the treatment.

  6. Impact of alpine meadow degradation on soil hydraulic properties over the Qinghai-Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zeng, Chen; Zhang, Fan; Wang, Quanjiu; Chen, Yingying; Joswiak, Daniel R.

    2013-01-01

    SummaryAlpine meadow soil is an important ecosystem component of the Qinghai-Tibetan Plateau. However, the alpine meadow soil is undergoing serious degradation mainly due to global climate change, overgrazing, human activities and rodents. In this paper, spatial sequencing was chosen over time succession sequencing to study the changes of soil hydraulic properties under different degrees of alpine meadow degradation. Soil saturated hydraulic conductivity (Ks) and Gardner α both at the surface and at 40-50 cm depth were investigated in the field using tension infiltrometers. Soil physical and chemical properties, together with the root index at 0-10 cm and 40-50 cm soil layer depths were also analyzed. Pearson correlations were adopted to study the relationships among the investigated factors and principal component analysis was performed to identify the dominant factor. Results show that with increasing degree of degradation, soil sand content increased while soil Ks and Gardner α as well as soil clay content, soil porosity decreased in the 0-10 cm soil layers, and organic matter and root gravimetric density decreased in both the 0-10 cm and 40-50 cm soil layers. However, soil moisture showed no significant changes with increasing degradation. With decreasing pressure head, soil unsaturated hydraulic conductivity reduced more slowly under degraded conditions than non-degraded conditions. Soil Ks and Gardner α were significantly correlated (P = 0.01) with bulk density, soil porosity, soil organic matter and root gravimetric density. Among these, soil porosity is the dominant factor explaining about 90% of the variability in total infiltration flow. Under non-degraded conditions, the infiltration flow principally depended on the presence of macropores. With increasing degree of degradation, soil macropores quickly changed to mesopores or micropores. The proportion of total infiltration flow through macropores and mesopores significantly decreased with the most

  7. Long term changes in Zostera meadows in the Berre lagoon (Provence, Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Bernard, Guillaume; Boudouresque, Charles F.; Picon, Philippe

    2007-07-01

    The Berre lagoon (Provence, France), one of the largest Mediterranean brackish lagoons (155 km 2), was occupied, at the turn of the 20th century, by extensive Zostera meadows ( Zostera marina and probably Zostera noltii; perhaps over 6000 ha). Subsequently, the lagoon was disturbed by urban and industrial pollution and, from 1966, by the diversion of the Durance River. This resulted in a 10-49-fold and 8-31-fold increase of the freshwater and silt inputs, respectively. By means of digital analysis of aerial photographs for the years 1944, 1992, 1998 and 2004, coupled with ground truth for the last three dates, we mapped the Zostera meadows. The replacement of Z. marina by Z. noltii, the latter species being already dominant in the 1970s, was completed in 1990. In parallel to this substitution, the Zostera beds underwent a dramatic decline. Their depth limit, which was (6-9) m in the early 20th century, withdrew to 3.5, 3, 1 and less than 1 m by 1944, the 1970s, 1992 and 1998, respectively. Since 1998, Zostera must be considered as functionally extinct. The total surface area of Zostera meadows was of the order of 1.5 ha in 2004. In an attempt to alleviate disturbance, the input of freshwater and silt from the Durance River was significantly reduced from the early 1980s and 1990s respectively. Similarly, from the 1970s to the 1990s, urban and domestic pollution was drastically reduced. Despite these steps, Zostera meadows continued to shrink to near extinction. The lagoon has shifted from a system dominated by seagrass beds to a system with bare silt bottoms, which now occupy most of the lagoon. The reasons could be, in addition to continuing nutrient inputs, the resuspension of silt, no longer trapped under the seagrass canopy, during wind episodes, which are frequent in the area, and/or the release of nutrients from the bare silt habitat, which would constitute an indication of a possible hysteresis of the system. However, since 2000, the establishment of the

  8. Redefining the trophic importance of seagrasses for fauna in tropical Indo-Pacific meadows

    NASA Astrophysics Data System (ADS)

    Vonk, Jan Arie; Christianen, Marjolijn J. A.; Stapel, Johan

    2008-09-01

    Fauna species living in seagrass meadows depend on different food sources, with seagrasses often being marginally important for higher trophic levels. To determine the food web of a mixed-species tropical seagrass meadow in Sulawesi, Indonesia, we analyzed the stable isotope ( δ13C and δ15N) signatures of primary producers, particulate organic matter (POM) and fauna species. In addition invertebrates, both infauna and macrobenthic, and fish densities were examined to identify the important species in the meadow. The aims of this study were to identify the main food sources of fauna species by comparing isotopic signatures of different primary producers and fauna, and to estimate qualitatively the importance of seagrass material in the food web. Phytoplankton and water column POM were the most depleted primary food sources for δ13C (range -23.1 to -19.6‰), but no fauna species depended only on these sources for carbon. Epiphytes and Sargassum sp. had intermediate δ13C values (-14.2 to -11.9‰). Sea urchins, gastropods and certain fish species were the main species assimilating this material. Seagrasses and sedimentary POM had the least depleted values (-11.5 to -5.7‰). Between the five seagrass species significant differences in δ13C were measured. The small species Halophila ovalis and Halodule uninervis were most depleted, the largest species Enhalus acoroides was least depleted, while Thalassia hemprichii and Cymodocea rotundata had intermediate values. Fourteen fauna species, accounting for ˜10% of the total fauna density, were shown to assimilate predominantly (>50%) seagrass material, either directly or indirectly by feeding on seagrass consumers. These species ranged from amphipods up to the benthic top predator Taeniura lymma. Besides these species, about half of the 55 fauna species analyzed had δ13C values higher than the least depleted non-seagrass source, indicating they depended at least partly for their food on seagrass material. This study

  9. Androgens exert opposite effects on body mass of heavy and light meadow voles.

    PubMed

    Dark, J; Whaling, C S; Zucker, I

    1987-12-01

    The influence of gonadal hormones on body mass of adult male meadow voles varied systematically as a function of the animals' baseline body weight; heavier voles decreased and lighter voles increased their body mass after castration. Testosterone replacement reversed the effects of castration; changes in body mass during hormone treatment were negatively correlated with changes observed after castration. Body mass of intact males was not correlated with plasma testosterone titers. Individual differences in body mass of male voles appear to reflect variations among animals in substrate responsiveness to hormones rather than differences in circulating hormone levels. PMID:3323026

  10. Prolactin counteracts effects of short day lengths on pelage growth in the meadow vole, Microtus pennsylvanicus.

    PubMed

    Smale, L; Lee, T M; Nelson, R J; Zucker, I

    1990-02-01

    To test whether growth of the winter coat in short day lengths is contingent on suppression of plasma prolactin (Prl) levels, female meadow voles (Microtus pennsylvanicus) were kept in short day lengths for 12 weeks and were injected daily with saline or Prl; long-day animals were treated with either the dopamine agonist, bromocryptine (bromo), bromo plus Prl, or saline. Prl treatment prevented the growth of the winter coat normally observed after 12 weeks in short day lengths, but bromocryptine did not stimulate pelage growth in long-day voles. Pelage growth in short day lengths appears contingent upon decreased plasma prolactin levels. PMID:2179462

  11. Maternal melatonin treatment influences rates of neonatal development of meadow vole pups.

    PubMed

    Lee, T M; Spears, N; Tuthill, C R; Zucker, I

    1989-03-01

    Meadow vole dams, housed in a 14L:10D photoperiod were injected daily 3 h before onset of darkness with 10 micrograms melatonin. Treatment during gestation or lactation produced offspring that exhibited altered somatic, testicular, and pelage growth. Gestational melatonin treatment decreased preweaning weight gain, delayed testicular development, and increased pelage growth in offspring, whereas melatonin treatment during lactation increased pelage depth at weaning and increased post-weaning somatic growth. These results suggest that pre- and postnatal maternal melatonin secretory patterns influence postnatal development of photosensitive traits in offspring. PMID:2667649

  12. Biogas production from ensiled meadow grass; effect of mechanical pretreatments and rapid determination of substrate biodegradability via physicochemical methods.

    PubMed

    Tsapekos, P; Kougias, P G; Angelidaki, I

    2015-04-01

    As the biogas sector is rapidly expanding, there is an increasing need in finding new alternative feedstock to biogas plants. Meadow grass can be a suitable co-substrate and if ensiled it can be supplied to biogas plants continuously throughout the year. Nevertheless, this substrate is quite recalcitrant and therefore efficient pretreatment is needed to permit easy access of microbes to the degradable components. In this study, different mechanical pretreatment methods were applied on ensiled meadow grass to investigate their effect on biomass biodegradability. All the tested pretreatments increased the methane productivity and the increase ranged from 8% to 25%. The best mechanical pretreatment was the usage of two coarse mesh grating plates. Additionally, simple analytical methods were conducted to investigate the possibility of rapidly determining the methane yield of meadow grass. Among the methods, electrical conductivity test showed the most promising calibration statistics (R(2)=0.68).

  13. [Ecological description of the ground beetle population (Coleoptera, Carabidae) in northern taiga meadows of Arkhangel'sk Region].

    PubMed

    Filippov, B Iu; Zezin, I S

    2006-01-01

    Species composition and ecological structure of ground beetle population was studied in northern taiga meadows of the Arkhangelsk Region. Meadows in the northern forest zone proved to harbor 91 ground beetle species. Carabid complexes formed in the intrazonal biocenoses of the northern forest zone can be as rich as the topical groups of the family in the southern forest zone by the number of species and ecological diversity. Ecological properties of the fauna and ground beetle population proved similar in different parts of the forest zone. The proportion of stenobiotic meadow species proved to decrease while that of ecologically plastic ones increased from south to north. The proportion of the genus Harpalus decreased in the ground beetle population while the number of Amara species remained unaltered and their abundance increased. The changes in the species composition caused no transformation of the ecological structure of ground beetle population since they are limited to a single life form or guild.

  14. Light-intensity grazing improves alpine meadow productivity and adaption to climate change on the Tibetan Plateau

    PubMed Central

    Zhang, Tao; Zhang, Yangjian; Xu, Mingjie; Zhu, Juntao; Wimberly, Michael C.; Yu, Guirui; Niu, Shuli; Xi, Yi; Zhang, Xianzhou; Wang, Jingsheng

    2015-01-01

    To explore grazing effects on carbon fluxes in alpine meadow ecosystems, we used a paired eddy-covariance (EC) system to measure carbon fluxes in adjacent fenced (FM) and grazed (GM) meadows on the Tibetan plateau. Gross primary productivity (GPP) and ecosystem respiration (Re) were greater at GM than FM for the first two years of fencing. In the third year, the productivity at FM increased to a level similar to the GM site. The higher productivity at GM was mainly caused by its higher photosynthetic capacity. Grazing exclusion did not increase carbon sequestration capacity for this alpine grassland system. The higher optimal photosynthetic temperature and the weakened ecosystem response to climatic factors at GM may help to facilitate the adaption of alpine meadow ecosystems to changing climate. PMID:26515954

  15. Estimates of ground-water discharge as determined from measurements of evapotranspiration, Ash Meadows area, Nye County, Nevada

    SciTech Connect

    Laczniak, R.J.; DeMeo, G.A.; Reiner, S.R.; Smith, J.L.; Nylund, W.E.

    1999-09-30

    Ash Meadows is one of the major discharge areas within the regional Death Valley ground-water flow system of southern Nevada and adjacent California. Ground water discharging at Ash Meadows is replenished from inflow derived from an extensive recharge area that includes the eastern part of the Nevada Test Site. This report presents results of a study to refine the estimate of ground-water discharge at Ash Meadows. The study estimates ground-water discharge from the Ash Meadows area through a rigorous quantification of evapotranspiration (ET). To accomplish this objective, the study identifies areas of ongoing ground-water ET, delineates unique areas of ET defined on the basis of similarities in vegetation and soil-moisture conditions, and computes ET rates for each of the delineated areas. A classification technique using spectral-reflectance characteristics determined from satellite images recorded in 1992 identified seven unique units representing areas of ground-water ET. Micrometeorological data were collected for a minimum of 1 year at each site during 1994 through 1997. Evapotranspiration ranged from 0.6 foot per year in a sparse, dry saltgrass environment to 8.6 feet per year over open water. Mean annual ET from the Ash Meadows area is estimated at 21,000 acre-feet. The estimates given for mean annual ground-water discharge range from 18,000 to 21,000 acre-feet. The range presented is only slightly higher than previous estimates of ground-water discharge from the Ash Meadows area based primarily on springflow measurements.

  16. Habitat-specific responses of leaf traits to soil water conditions in species from a novel alpine swamp meadow community

    PubMed Central

    Li, Honglin; Nicotra, Adrienne B.; Xu, Danghui; Du, Guozhen

    2015-01-01

    Species originally from alpine wetland and alpine meadow communities now coexist in a novel ‘alpine swamp meadow’ community as a consequence of wetland drying in the eastern Tibetan Plateau. Considering the projected increase in the fluctuation of water supply from precipitation during the growing season in this area in the future, it is important to investigate the responses of the species that make up this new community to soil water availability. Using a transplant experimental design, we compared the response of leaf traits and growth to different water conditions for species grouped according to their original habitat of wetland or meadow. Twelve perennial herbaceous species, which form an alpine swamp meadow community in Maqu County in the eastern Tibetan Plateau, were used in this study and subjected to two water treatments, namely waterlogged and dry-down. Overall, significant differences in leaf production in response to soil water availability were found for these two groups, indicating strongly different effects of water availability on their growth. Furthermore, the meadow group had lower specific leaf area, leaf area and relative leaf water content, but thicker leaves than those of the wetland group, indicating significant habitat-specific differences in leaf morphology. Regarding physiological traits, the wetland group had significantly higher photosynthetic rates in inundated conditions, whereas for the meadow group the photosynthetic rate was greatest in cyclically dry conditions. Likewise, a similar pattern was observed for stomatal conductance; however, both groups achieved higher instantaneous water use efficiency during the dry-down treatment. The results of this study indicate that the composition of the alpine swamp meadow could be sensitive to changes in precipitation and might be changed substantially by future declines in water supply, as predicted by global climate change models for this region. This potential for compositional change

  17. Relative abundance and distribution of fishes and crayfish at Ash Meadows National Wildlife Refuge, Nye County, Nevada, 2010-11

    USGS Publications Warehouse

    Scoppettone, G.G.; Johnson, D.M.; Hereford, M.E.; Rissler, Peter; Fabes, Mark; Salgado, Antonio; Shea, Sean

    2012-01-01

    Habitat restoration that favors native species can help control non-native species (McShane and others, 2004; Scoppettone and others, 2005; Kennedy and others, 2006). Restoration of Carson Slough and its tributaries present an opportunity to promote habitat types that favor native species over non-natives. Historically, the majority of Ash Meadows spring systems were tributaries to Carson Slough. In 2007 and 2008, a survey of Ash Meadows spring systems was conducted to generate baseline information on the distribution of fishes throughout AMNWR (Scoppettone and others, 2011b). In this study, w

  18. Macroecological analysis of the fish fauna inhabiting Cymodocea nodosa seagrass meadows.

    PubMed

    Espino, F; Brito, A; Haroun, R; Tuya, F

    2015-10-01

    In this study, patterns in the taxonomic richness and composition of the fish fauna inhabiting Cymodocea nodosa seagrass meadows were described across their entire distribution range in the Mediterranean Sea and adjacent Atlantic Ocean. Specifically, the study tested whether there are differences in the composition of fish assemblages between those ecoregions encompassed by the distribution range of C. nodosa, and whether these differences in composition are connected with differences in bioclimatic affinities of the fish faunas. A literature review resulted in a total of 19 studies, containing 22 fish assemblages at 18 locations. The ichthyofauna associated with C. nodosa seagrass meadows comprises 59 families and 188 species. The western Mediterranean (WM) Sea has the highest species richness (87 species). Fish assemblages from the Macaronesia-Canary Islands, the Sahelian Upwelling, South European Atlantic Shelf and the WM differ, in terms of assemblage composition, relative to other ecoregions. In contrast, the composition of the fish fauna from the central and eastern Mediterranean overlaps. There is a significant serial correlation in fish assemblage composition between adjacent ecoregions along the distribution range of C. nodosa. Dissimilarities in assemblage composition are connected with the geographical separation between locations, and the mean minimum annual seawater temperature is the environmental factor that explains most variation in fish assemblage composition. PMID:26436373

  19. Spatially characterizing visitor use and its association with informal trails in Yosemite Valley meadows.

    PubMed

    Walden-Schreiner, Chelsey; Leung, Yu-Fai

    2013-07-01

    Ecological impacts associated with nature-based recreation and tourism can compromise park and protected area goals if left unrestricted. Protected area agencies are increasingly incorporating indicator-based management frameworks into their management plans to address visitor impacts. Development of indicators requires empirical evaluation of indicator measures and examining their ecological and social relevance. This study addresses the development of the informal trail indicator in Yosemite National Park by spatially characterizing visitor use in open landscapes and integrating use patterns with informal trail condition data to examine their spatial association. Informal trail and visitor use data were collected concurrently during July and August of 2011 in three, high-use meadows of Yosemite Valley. Visitor use was clustered at statistically significant levels in all three study meadows. Spatial data integration found no statistically significant differences between use patterns and trail condition class. However, statistically significant differences were found between the distance visitors were observed from informal trails and visitor activity type with active activities occurring closer to trail corridors. Gender was also found to be significant with male visitors observed further from trail corridors. Results highlight the utility of integrated spatial analysis in supporting indicator-based monitoring and informing management of open landscapes. Additional variables for future analysis and methodological improvements are discussed.

  20. Soil bacterial community responses to warming and grazing in a Tibetan alpine meadow.

    PubMed

    Li, Yaoming; Lin, Qiaoyan; Wang, Shiping; Li, Xiangzhen; Liu, Wentso; Luo, Caiyun; Zhang, Zhenhua; Zhu, Xiaoxue; Jiang, Lili; Li, Xine

    2016-01-01

    Warming and grazing significantly affect the structure and function of an alpine meadow ecosystem. Yet, the responses of soil microbes to these disturbances are not well understood. Controlled asymmetrical warming (+1.2/1.7°C during daytime/nighttime) with grazing experiments were conducted to study microbial response to warming, grazing and their interactions. Significant interactive effects of warming and grazing were observed on soil bacterial α-diversity and composition. Warming only caused significant increase in bacterial α-diversity under no-grazing conditions. Grazing induced no substantial differences in bacterial α-diversity and composition irrespective of warming. Warming, regardless of grazing, caused a significant increase in soil bacterial community similarity across space, but grazing only induced significant increases under no-warming conditions. The positive effects of warming on bacterial α-diversity and grazing on community similarity were weakened by grazing and warming, respectively. Soil and plant variables explained well the variations in microbial communities, indicating that changes in soil and plant properties may primarily regulate soil microbial responses to warming in this alpine meadow. The results suggest that bacterial communities may become more similar across space in a future, warmed climate and moderate grazing may potentially offset, at least partially, the effects of global warming on the soil microbial diversity. PMID:26635411

  1. Contrasting soil microbial community functional structures in two major landscapes of the Tibetan alpine meadow

    SciTech Connect

    Chu, Houjuan; Wang, Shiping; Yue, Haowei; Lin, Qiaoyan; Hu, Yigang; Li, Xiangzhen; Zhou, Jizhong; Yang, Yunfeng

    2014-07-07

    The grassland and shrubland are two major landscapes of the Tibetan alpine meadow, a region very sensitive to the impact of global warming and anthropogenic perturbation. Herein, we report a study showing that a majority of differences in soil microbial community functional structures, measured by a functional gene array named GeoChip 4.0, in two adjacent shrubland and grassland areas, were explainable by environmental properties, suggesting that the harsh environments in the alpine grassland rendered niche adaptation important. Furthermore, genes involved in labile carbon degradation were more abundant in the shrubland than those of the grassland but genes involved in recalcitrant carbon degradation were less abundant, which was conducive to long-term carbon storage and sequestration in the shrubland despite low soil organic carbon content. In addition, genes of anerobic nitrogen cycling processes such as denitrification and dissimilatory nitrogen reduction were more abundant, shifting soil nitrogen cycling toward ammonium biosynthesis and consequently leading to higher soil ammonium contents. We also noted higher abundances of stress genes responsive to nitrogen limitation and oxygen limitation, which might be attributed to low total nitrogen and higher water contents in the shrubland. Together, these results provide mechanistic knowledge about microbial linkages to soil carbon and nitrogen storage and potential consequences of vegetation shifts in the Tibetan alpine meadow.

  2. Temporal patterns of orchid mycorrhizal fungi in meadows and forests as revealed by 454 pyrosequencing.

    PubMed

    Oja, Jane; Kohout, Petr; Tedersoo, Leho; Kull, Tiiu; Kõljalg, Urmas

    2015-03-01

    Orchid mycorrhizal (OrM) symbionts play a key role in the growth of orchids, but the temporal variation and habitat partitioning of these fungi in roots and soil remain unclear. Temporal changes in root and rhizosphere fungal communities of Cypripedium calceolus, Neottia ovata and Orchis militaris were studied in meadow and forest habitats over the vegetation period by using 454 pyrosequencing of the full internal transcribed spacer (ITS) region. The community of typical OrM symbionts differed by plant species and habitats. The root fungal community of N. ovata changed significantly in time, but this was not observed in C. calceolus and O. militaris. The rhizosphere community included a low proportion of OrM symbionts that exhibited a slight temporal turnover in meadow habitats but not in forests. Habitat differences in OrM and all fungal associates are largely attributable to the greater proportion of ectomycorrhizal fungi in forests. Temporal changes in OrM fungal communities in roots of certain species indicate selection of suitable fungal species by plants. It remains to be elucidated whether these shifts depend on functional differences inside roots, seasonality, climate or succession.

  3. Effects of environmental complexity and temporary captivity on foraging behavior of wild-caught meadow voles.

    PubMed

    Kozuch, Amaranta E; McPhee, M Elsbeth

    2014-01-01

    Increased housing of wild nonhuman animals in captivity for conservation, research, and rehabilitation has revealed the importance of systematically analyzing effects of the captive environment on behavior. This study focused on the effects of complexity and time held in captivity on foraging behaviors of wild-caught, adult meadow voles (Microtus pennsylvanicus). Forty-six individuals captured from a meadow outside Oshkosh, WI, were assigned to 1 of 4 captive treatment groups: simple/<50 days (SS), simple/>50 days, complex/<50 days, and complex/>50 days. Number of dish visits, proportion foraging, and frequency of nonforaging behaviors recorded during a 15-min foraging trial were measured for all subjects. Kruskal-Wallis and Mann-Whitney U Tests were conducted to analyze 4 different comparisons within this behavioral data. Overall, neither time in captivity or environmental complexity affected nonforaging behaviors. In contrast, foraging behaviors did change with treatment: Voles were less active at food dishes and visited control dishes more in treatment group SS than in the other treatment groups. In addition, sex-related differences in foraging behaviors were maintained when voles were exposed to environmental complexity. This article includes options for wildlife managers to adapt captive environments to meet the welfare and behavioral needs of translocated wild nonhuman mammals. PMID:24559285

  4. Uptake of galaxolide, tonalide, and triclosan by carrot, barley, and meadow fescue plants.

    PubMed

    Macherius, André; Eggen, Trine; Lorenz, Wilhelm Georg; Reemtsma, Thorsten; Winkler, Ursula; Moeder, Monika

    2012-08-15

    Many xenobiotics entering wastewater treatment plants are known to be persistent during wastewater treatment and tend to adsorb to sewage sludge. The application of sewage sludge as fertilizer in agriculture may pose the risk of an incorporation of xenobiotics in the cultivated plants and, finally, an inclusion into the food chain. This study was performed to investigate the uptake of common sewage sludge contaminants, galaxolide, tonalide, and triclosan, by plants used for human consumption and livestock feeding. Barley, meadow fescue, and four carrot cultivars were sown and grown in spiked soils under greenhouse conditions. After harvesting the plants, roots and leaves were analyzed separately, and the respective bioconcentration factors were calculated. In carrots, a concentration gradient of the xenobiotics became evident that decreased from the root peel via root core to the leaves. A significant influence of the differing root lipid contents on the uptake rates cannot be supported by our data, but the crucial influence of soil organic carbon content was confirmed. Barley and meadow fescue roots incorporated higher amounts of the target substances than carrots, but translocation into the leaves was negligible. The results indicated that an introduction of persistent semi- and nonpolar xenobiotics into the food chain via edible plants like carrots could be of certain relevance when sludge is applied as fertilizer. Due to low rates found for the translocation of the xenobiotics into the aerial plant parts, the entrance pathway into food products via feeding livestock is less probable.

  5. Biodiversity loss in seagrass meadows due to local invertebrate fisheries and harbour activities

    NASA Astrophysics Data System (ADS)

    Nordlund, Lina Mtwana; Gullström, Martin

    2013-12-01

    Seagrass meadows provide a wide variety of ecosystem services, but their distribution and health are adversely affected by man. In the present study, we examined the influence of coastal exploitation in terms of invertebrate harvesting and harbour activity on invertebrate community composition in subtropical seagrass meadows at Inhaca Island, Mozambique, in the Western Indian Ocean. There was a fivefold higher invertebrate density and biomass, and clearly higher invertebrate species richness, in the protected (control) site compared to the two exploited sites. The causes for the clear differences between protected and exploited sites were probably a result of (1) the directional outtake of large edible or saleable invertebrates (mostly molluscs) and the absence of boat traffic in the harvested site, and (2) harbour activities. Invertebrate community composition in the two exploited sites also differed (although less clear), which was likely due to inherent distinction in type of disturbance. Our findings revealed that protection of seagrass habitat is necessary and that disturbances of different origin might require different forms of management and conservation. Designing protected areas is however a complex process due to competition for use and space with activities such as invertebrate harvesting and harbours.

  6. Spatially Characterizing Visitor Use and Its Association with Informal Trails in Yosemite Valley Meadows

    NASA Astrophysics Data System (ADS)

    Walden-Schreiner, Chelsey; Leung, Yu-Fai

    2013-07-01

    Ecological impacts associated with nature-based recreation and tourism can compromise park and protected area goals if left unrestricted. Protected area agencies are increasingly incorporating indicator-based management frameworks into their management plans to address visitor impacts. Development of indicators requires empirical evaluation of indicator measures and examining their ecological and social relevance. This study addresses the development of the informal trail indicator in Yosemite National Park by spatially characterizing visitor use in open landscapes and integrating use patterns with informal trail condition data to examine their spatial association. Informal trail and visitor use data were collected concurrently during July and August of 2011 in three, high-use meadows of Yosemite Valley. Visitor use was clustered at statistically significant levels in all three study meadows. Spatial data integration found no statistically significant differences between use patterns and trail condition class. However, statistically significant differences were found between the distance visitors were observed from informal trails and visitor activity type with active activities occurring closer to trail corridors. Gender was also found to be significant with male visitors observed further from trail corridors. Results highlight the utility of integrated spatial analysis in supporting indicator-based monitoring and informing management of open landscapes. Additional variables for future analysis and methodological improvements are discussed.

  7. Effects of common seagrass restoration methods on ecosystem structure in subtropical seagrass meadows.

    PubMed

    Bourque, Amanda S; Fourqurean, James W

    2014-06-01

    Seagrass meadows near population centers are subject to frequent disturbance from vessel groundings. Common seagrass restoration methods include filling excavations and applying fertilizer to encourage seagrass recruitment. We sampled macrophytes, soil structure, and macroinvertebrate infauna at unrestored and recently restored vessel grounding disturbances to evaluate the effects of these restoration methods on seagrass ecosystem structure. After a year of observations comparing filled sites to both undisturbed reference and unrestored disturbed sites, filled sites had low organic matter content, nutrient pools, and primary producer abundance. Adding a nutrient source increased porewater nutrient pools at disturbed sites and in undisturbed meadows, but not at filled sites. Environmental predictors of infaunal community structure across treatments included soil texture and nutrient pools. At the one year time scale, the restoration methods studied did not result in convergence between restored and unrestored sites. Particularly in filled sites, soil conditions may combine to constrain rapid development of the seagrass community and associated infauna. Our study is important for understanding early recovery trajectories following restoration using these methods.

  8. Contrasting soil microbial community functional structures in two major landscapes of the Tibetan alpine meadow.

    PubMed

    Chu, Houjuan; Wang, Shiping; Yue, Haowei; Lin, Qiaoyan; Hu, Yigang; Li, Xiangzhen; Zhou, Jizhong; Yang, Yunfeng

    2014-10-01

    The grassland and shrubland are two major landscapes of the Tibetan alpine meadow, a region very sensitive to the impact of global warming and anthropogenic perturbation. Herein, we report a study showing that a majority of differences in soil microbial community functional structures, measured by a functional gene array named GeoChip 4.0, in two adjacent shrubland and grassland areas, were explainable by environmental properties, suggesting that the harsh environments in the alpine grassland rendered niche adaptation important. Furthermore, genes involved in labile carbon degradation were more abundant in the shrubland than those of the grassland but genes involved in recalcitrant carbon degradation were less abundant, which was conducive to long-term carbon storage and sequestration in the shrubland despite low soil organic carbon content. In addition, genes of anerobic nitrogen cycling processes such as denitrification and dissimilatory nitrogen reduction were more abundant, shifting soil nitrogen cycling toward ammonium biosynthesis and consequently leading to higher soil ammonium contents. We also noted higher abundances of stress genes responsive to nitrogen limitation and oxygen limitation, which might be attributed to low total nitrogen and higher water contents in the shrubland. Together, these results provide mechanistic knowledge about microbial linkages to soil carbon and nitrogen storage and potential consequences of vegetation shifts in the Tibetan alpine meadow.

  9. Contrasting soil microbial community functional structures in two major landscapes of the Tibetan alpine meadow

    PubMed Central

    Chu, Houjuan; Wang, Shiping; Yue, Haowei; Lin, Qiaoyan; Hu, Yigang; Li, Xiangzhen; Zhou, Jizhong; Yang, Yunfeng

    2014-01-01

    The grassland and shrubland are two major landscapes of the Tibetan alpine meadow, a region very sensitive to the impact of global warming and anthropogenic perturbation. Herein, we report a study showing that a majority of differences in soil microbial community functional structures, measured by a functional gene array named GeoChip 4.0, in two adjacent shrubland and grassland areas, were explainable by environmental properties, suggesting that the harsh environments in the alpine grassland rendered niche adaptation important. Furthermore, genes involved in labile carbon degradation were more abundant in the shrubland than those of the grassland but genes involved in recalcitrant carbon degradation were less abundant, which was conducive to long-term carbon storage and sequestration in the shrubland despite low soil organic carbon content. In addition, genes of anerobic nitrogen cycling processes such as denitrification and dissimilatory nitrogen reduction were more abundant, shifting soil nitrogen cycling toward ammonium biosynthesis and consequently leading to higher soil ammonium contents. We also noted higher abundances of stress genes responsive to nitrogen limitation and oxygen limitation, which might be attributed to low total nitrogen and higher water contents in the shrubland. Together, these results provide mechanistic knowledge about microbial linkages to soil carbon and nitrogen storage and potential consequences of vegetation shifts in the Tibetan alpine meadow. PMID:25044404

  10. Macroecological analysis of the fish fauna inhabiting Cymodocea nodosa seagrass meadows.

    PubMed

    Espino, F; Brito, A; Haroun, R; Tuya, F

    2015-10-01

    In this study, patterns in the taxonomic richness and composition of the fish fauna inhabiting Cymodocea nodosa seagrass meadows were described across their entire distribution range in the Mediterranean Sea and adjacent Atlantic Ocean. Specifically, the study tested whether there are differences in the composition of fish assemblages between those ecoregions encompassed by the distribution range of C. nodosa, and whether these differences in composition are connected with differences in bioclimatic affinities of the fish faunas. A literature review resulted in a total of 19 studies, containing 22 fish assemblages at 18 locations. The ichthyofauna associated with C. nodosa seagrass meadows comprises 59 families and 188 species. The western Mediterranean (WM) Sea has the highest species richness (87 species). Fish assemblages from the Macaronesia-Canary Islands, the Sahelian Upwelling, South European Atlantic Shelf and the WM differ, in terms of assemblage composition, relative to other ecoregions. In contrast, the composition of the fish fauna from the central and eastern Mediterranean overlaps. There is a significant serial correlation in fish assemblage composition between adjacent ecoregions along the distribution range of C. nodosa. Dissimilarities in assemblage composition are connected with the geographical separation between locations, and the mean minimum annual seawater temperature is the environmental factor that explains most variation in fish assemblage composition.

  11. Contrasting soil microbial community functional structures in two major landscapes of the Tibetan alpine meadow

    DOE PAGESBeta

    Chu, Houjuan; Wang, Shiping; Yue, Haowei; Lin, Qiaoyan; Hu, Yigang; Li, Xiangzhen; Zhou, Jizhong; Yang, Yunfeng

    2014-07-07

    The grassland and shrubland are two major landscapes of the Tibetan alpine meadow, a region very sensitive to the impact of global warming and anthropogenic perturbation. Herein, we report a study showing that a majority of differences in soil microbial community functional structures, measured by a functional gene array named GeoChip 4.0, in two adjacent shrubland and grassland areas, were explainable by environmental properties, suggesting that the harsh environments in the alpine grassland rendered niche adaptation important. Furthermore, genes involved in labile carbon degradation were more abundant in the shrubland than those of the grassland but genes involved in recalcitrantmore » carbon degradation were less abundant, which was conducive to long-term carbon storage and sequestration in the shrubland despite low soil organic carbon content. In addition, genes of anerobic nitrogen cycling processes such as denitrification and dissimilatory nitrogen reduction were more abundant, shifting soil nitrogen cycling toward ammonium biosynthesis and consequently leading to higher soil ammonium contents. We also noted higher abundances of stress genes responsive to nitrogen limitation and oxygen limitation, which might be attributed to low total nitrogen and higher water contents in the shrubland. Together, these results provide mechanistic knowledge about microbial linkages to soil carbon and nitrogen storage and potential consequences of vegetation shifts in the Tibetan alpine meadow.« less

  12. Effects of Water and Nitrogen Addition on Ecosystem Carbon Exchange in a Meadow Steppe

    PubMed Central

    Wang, Yunbo; Jiang, Qi; Yang, Zhiming; Sun, Wei; Wang, Deli

    2015-01-01

    A changing precipitation regime and increasing nitrogen deposition are likely to have profound impacts on arid and semiarid ecosystem C cycling, which is often constrained by the timing and availability of water and nitrogen. However, little is known about the effects of altered precipitation and nitrogen addition on grassland ecosystem C exchange. We conducted a 3-year field experiment to assess the responses of vegetation composition, ecosystem productivity, and ecosystem C exchange to manipulative water and nitrogen addition in a meadow steppe. Nitrogen addition significantly stimulated aboveground biomass and net ecosystem CO2 exchange (NEE), which suggests that nitrogen availability is a primary limiting factor for ecosystem C cycling in the meadow steppe. Water addition had no significant impacts on either ecosystem C exchange or plant biomass, but ecosystem C fluxes showed a strong correlation with early growing season precipitation, rather than whole growing season precipitation, across the 3 experimental years. After we incorporated water addition into the calculation of precipitation regimes, we found that monthly average ecosystem C fluxes correlated more strongly with precipitation frequency than with precipitation amount. These results highlight the importance of precipitation distribution in regulating ecosystem C cycling. Overall, ecosystem C fluxes in the studied ecosystem are highly sensitive to nitrogen deposition, but less sensitive to increased precipitation. PMID:26010888

  13. Soil bacterial community responses to warming and grazing in a Tibetan alpine meadow.

    PubMed

    Li, Yaoming; Lin, Qiaoyan; Wang, Shiping; Li, Xiangzhen; Liu, Wentso; Luo, Caiyun; Zhang, Zhenhua; Zhu, Xiaoxue; Jiang, Lili; Li, Xine

    2016-01-01

    Warming and grazing significantly affect the structure and function of an alpine meadow ecosystem. Yet, the responses of soil microbes to these disturbances are not well understood. Controlled asymmetrical warming (+1.2/1.7°C during daytime/nighttime) with grazing experiments were conducted to study microbial response to warming, grazing and their interactions. Significant interactive effects of warming and grazing were observed on soil bacterial α-diversity and composition. Warming only caused significant increase in bacterial α-diversity under no-grazing conditions. Grazing induced no substantial differences in bacterial α-diversity and composition irrespective of warming. Warming, regardless of grazing, caused a significant increase in soil bacterial community similarity across space, but grazing only induced significant increases under no-warming conditions. The positive effects of warming on bacterial α-diversity and grazing on community similarity were weakened by grazing and warming, respectively. Soil and plant variables explained well the variations in microbial communities, indicating that changes in soil and plant properties may primarily regulate soil microbial responses to warming in this alpine meadow. The results suggest that bacterial communities may become more similar across space in a future, warmed climate and moderate grazing may potentially offset, at least partially, the effects of global warming on the soil microbial diversity.

  14. Ecology of eelgrass meadows of the Atlantic Coast: a community profile

    SciTech Connect

    Thayer, G.W.; Kenworthy, W.J.; Fonseca, M.S.

    1984-07-01

    Eelgrass, Zostera marina, dominates the ecologically important but fragile seagrass communities along the east coast of the United States from North Carolina to Nova Scotia. Grasslike leaves and an extensive root and rhizome system enable eelgrass to exist in a shallow aquatic environment subject to waves, tides, and shifting sediments. Eelgrass meadows are highly productive, frequently rivaling agricultural croplands. They provide shelter and a rich variety of primary and secondary food resources, and form a nursery habitat for the life history stages of numerous fishery organisms. The leaves absorb and release nutrients, provide surfaces for attachment, reduce water current velocity, turbulence and scour, and promote accumulation of detritus. Rhizomes provide protection for benthic infauna and enhance sediment stability. Roots absorb and release nutrients to interstitial waters. Because of their shallow, subtidal existence, seagrasses are susceptible to perturbations of both the water column and sediments. Eelgrass meadows are impacted by dredging and filling, some commercial fishery harvest techniques, modification of normal temperature and salinity regimes, and addition of chemical wastes. Techniques have been developed to successfully restore eelgrass habitats, but a holistic approach to planning research and environmentally-related decisions is needed to avoid cumulative environmental impacts on these vital nursery areas. 64 figures, 16 tables.

  15. Small mammal populations in Maryland meadows during four years of herbicide (Brominal? ) applications

    USGS Publications Warehouse

    Clark, D.R.; Moulton, C.A.; Hines, J.E.; Hoffman, D.J.

    1996-01-01

    The herbicide Brominal? was applied at the recommended rate to one plot in each of three paired 0.6-ha plots; the other three plots were used as controls. Plots were sprayed once in the fall of 1988 and 1989 and twice in the spring of 1990 and 1991. Small mammals were trapped three times during each activity season (April?October) to obtain population estimates before and after spraying and in the spring preceding fall spraying or the fall following spring spraying. Population estimates immediately after spraying gave no evidence of direct mortality. By 1991, dicot vegetation on treated plots was suppressed and mean numbers of meadow voles (Microtus pennsylvanicus) were less than on control plots. Because meadow voles favor dicots over monocots in their diet, reduced availability of dicots may have been related to the smaller vole population estimates. Species diversity of small mammals was negatively correlated with size of vole populations, but was not different between treated and control plots. Brominal apparently induced opaque corneas in nine voles. The condition was found in two voles too small to have been conceived at the time of the last previous spray nearly 8 months earlier, suggesting exposure to residue alone.

  16. The exergy of a phase shift: Ecosystem functioning loss in seagrass meadows of the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Montefalcone, Monica; Vassallo, Paolo; Gatti, Giulia; Parravicini, Valeriano; Paoli, Chiara; Morri, Carla; Bianchi, Carlo Nike

    2015-04-01

    Sustained functioning of ecosystems is predicted to depend upon the maintenance of their biodiversity, structure and integrity. The large consensus achieved in this regard, however, faces to the objective difficulty of finding appropriate metrics to measure ecosystem functioning. Here, we aim at evaluating functional consequence of the phase shift occurring in meadows of the Mediterranean seagrass Posidonia oceanica, a priority habitat that is undergoing regression in many coastal areas due to multiple human pressures. Structural degradation of the P. oceanica ecosystem, consequent to increasing coastal exploitation and climate change, may result in the progressive replacement of this seagrass by opportunistic macrophytes, either native or alien. Reviewing published information and our personal records, we measured changes in biological habitat provisioning, species richness and biomass associated to each of the alternative states characterizing the phase shift. Then, ecosystem functioning was assessed by computing the exergy associated to each state, exergy being a state variable that measures the ecosystem capacity to produce work. Phase shift was consistently shown to imply loss in habitat provision, species richness, and biomass; structural and compositional loss was parallelled by a reduction of exergy content, thus providing for the first time an objective and integrative measure of the loss of ecosystem functioning following the degradation of healthy seagrass meadows.

  17. Environmental modulation of same-sex affiliative behavior in female meadow voles (Microtus pennsylvanicus).

    PubMed

    Ondrasek, Naomi R; Wade, Adam; Burkhard, Tracy; Hsu, Kacie; Nguyen, Tiffany; Post, Jessica; Zucker, Irving

    2015-03-01

    The effects of temperature and food availability on social bonds and group formation are poorly understood. Because seasonal transitions in female social behavior facilitate the assembly of winter groups in meadow voles, we explored the role of same-sex female associations in winter sociality. To examine the effects of winter typical environmental conditions on same-sex female affiliative behavior, paired female meadow voles were housed in varying combinations of day length, temperature, and food availability for 7weeks and then tested for social preference. In short days (SDs), lower ambient temperature increased huddling with unfamiliar females without interfering with existing social bonds, whereas lower temperature disrupted the retention of bonds in long days (LDs). Mild food restriction with no discernible effects on body mass enhanced affiliative behavior in SDs, but not LDs. A second experiment examined the effects of sex and day length on the propensity to aggregate with unfamiliar same-sex voles. Compared to LD females and SD males, SD females spent more time in group huddles with unfamiliar voles and displayed no social preference. These outcomes indicate that winter-like conditions enhance affiliative behavior between females and that pre-existing social bonds do not preclude integration into new winter social groups. The adaptive value of these behaviors is discussed. PMID:25497080

  18. Chronic exposure to gamma radiation of wild populations of meadow voles (Microtus pennsylvanicus).

    PubMed

    Mihok, Steve

    2004-01-01

    Free-ranging, wild meadow voles (Microtus pennsylvanicus) were exposed to gamma radiation from a (137)Cs irradiator in a series of experiments conducted on six 1-ha meadows within a mixed deciduous forest in Manitoba, Canada. Over a period of 1-1.5 years in each of three experiments, vole populations were monitored with capture-mark-release techniques at nominal exposure rates of 200x, 9000x and 40,000x background. No effects on population or individual characteristics were detected up to the highest exposure rate (81 mGy/d). At this level, third generation voles were monitored up to a lifetime dose of about 5.7 Gy, at a measured dose rate of 44 mGy/d. Smaller numbers of overwintered animals survived and reproduced normally at doses up to 10 Gy. These results are discussed in terms of low-LET, external chronic radiation effects on rodents in the laboratory and the field, relative to current views on appropriate benchmarks for the protection of biota.

  19. Effects of environmental complexity and temporary captivity on foraging behavior of wild-caught meadow voles.

    PubMed

    Kozuch, Amaranta E; McPhee, M Elsbeth

    2014-01-01

    Increased housing of wild nonhuman animals in captivity for conservation, research, and rehabilitation has revealed the importance of systematically analyzing effects of the captive environment on behavior. This study focused on the effects of complexity and time held in captivity on foraging behaviors of wild-caught, adult meadow voles (Microtus pennsylvanicus). Forty-six individuals captured from a meadow outside Oshkosh, WI, were assigned to 1 of 4 captive treatment groups: simple/<50 days (SS), simple/>50 days, complex/<50 days, and complex/>50 days. Number of dish visits, proportion foraging, and frequency of nonforaging behaviors recorded during a 15-min foraging trial were measured for all subjects. Kruskal-Wallis and Mann-Whitney U Tests were conducted to analyze 4 different comparisons within this behavioral data. Overall, neither time in captivity or environmental complexity affected nonforaging behaviors. In contrast, foraging behaviors did change with treatment: Voles were less active at food dishes and visited control dishes more in treatment group SS than in the other treatment groups. In addition, sex-related differences in foraging behaviors were maintained when voles were exposed to environmental complexity. This article includes options for wildlife managers to adapt captive environments to meet the welfare and behavioral needs of translocated wild nonhuman mammals.

  20. Temporal patterns of orchid mycorrhizal fungi in meadows and forests as revealed by 454 pyrosequencing.

    PubMed

    Oja, Jane; Kohout, Petr; Tedersoo, Leho; Kull, Tiiu; Kõljalg, Urmas

    2015-03-01

    Orchid mycorrhizal (OrM) symbionts play a key role in the growth of orchids, but the temporal variation and habitat partitioning of these fungi in roots and soil remain unclear. Temporal changes in root and rhizosphere fungal communities of Cypripedium calceolus, Neottia ovata and Orchis militaris were studied in meadow and forest habitats over the vegetation period by using 454 pyrosequencing of the full internal transcribed spacer (ITS) region. The community of typical OrM symbionts differed by plant species and habitats. The root fungal community of N. ovata changed significantly in time, but this was not observed in C. calceolus and O. militaris. The rhizosphere community included a low proportion of OrM symbionts that exhibited a slight temporal turnover in meadow habitats but not in forests. Habitat differences in OrM and all fungal associates are largely attributable to the greater proportion of ectomycorrhizal fungi in forests. Temporal changes in OrM fungal communities in roots of certain species indicate selection of suitable fungal species by plants. It remains to be elucidated whether these shifts depend on functional differences inside roots, seasonality, climate or succession. PMID:25546739

  1. Long day lengths enhance myelination of midbrain and hindbrain regions of developing meadow voles.

    PubMed

    Spears, N; Meyer, J S; Whaling, C S; Wade, G N; Zucker, I; Dark, J

    1990-08-01

    Rates of brain growth differed in meadow voles maintained in long (LP) or short (SP) photoperiods postnatally. At 35 days of age, brain weight was greater by 6.6% in LP males and by 4.7% in LP females as compared to their SP counterparts. Whole brain galactolipid content, an index of brain myelin, was greater by 15.6% in LP as compared to SP males. At 70 days of age, brains of LP males were 4% heavier than those of SP males. Differences attributable to photoperiod were most pronounced in midbrain and hindbrain (8% and 14%, respectively). DNA and galactolipid contents were greater by 11% and 15%, respectively, in hindbrain of LP males. Photoperiod did not affect any of these measures in diencephalon, striatum, or cerebellum. Short day lengths reduce myelination in meadow voles, presumably by decreasing proliferation rates of oligodendroglia. This is one facet of a general delay in somatic development associated with being born at the end of the normal breeding season when day lengths are decreasing or below a critical threshold. PMID:2208634

  2. Same-sex social behavior in meadow voles: Multiple and rapid formation of attachments.

    PubMed

    Beery, Annaliese K; Routman, David M; Zucker, Irving

    2009-04-20

    Adult meadow voles (Microtus pennsylvanicus) are solitary in the spring-summer reproductive season, but during winter months, females and males are socially tolerant and aggregate in groups. This behavioral difference is triggered by day length: female meadow voles housed in short, winter-like day lengths form same-sex partner preferences, whereas those housed in long, summer-like day lengths are less social. The present study demonstrates that same-sex social attachments in short day lengths are not exclusive; females formed concurrent attachments with more than one individual, and with non-kin as well as siblings. Partner preferences between females were established within one day of cohousing and did not intensify with greater durations of cohabitation. Males also formed same-sex social attachments, but unlike female affiliative behavior, male partner preferences were not significantly affected by day length. These data are discussed in the context of field behavior and the physiological mechanisms supporting social behavior in voles. PMID:19419672

  3. Spectrophotometric system to develop a non-invasive method for monitoring of posidonia oceanica meadows

    NASA Astrophysics Data System (ADS)

    Menesatti, P.; Urbani, G.; Dolce, T.

    2007-09-01

    Posidonia oceanica (L.) is an endemic phanerogam of the Mediterranean Sea. It lives between 0.2 and 40 m depth and make up extensive meadows that play a fundamental role in the marine coast ecosystem. Near the coasts at higher anthropic pressure, Posidonia meadows present both quality and quantity damages (regression) due to the mechanical operations on the seabed (anchoring, drag netting, pipe lines) and the sea pollution. Nowadays, the seagrass regression is monitored by different systems: aereophotografic, side scan sonar, underwater television camera, direct underwater visual inspection. Scientific community is looking for to develop monitoring systems more reliable, rapid and non invasive. Aim of this study is to evaluate the application of a new spectrophotometric imaging system based on the acquisition of reflectance spectral images with a good optical (250 Kpixels) and spectral resolution (spectral range 400-970 nm, a total of 115 single wavelength, 5 nm step each one). First trials were made on Posidonia's leafs to evaluate the system capacity to recognize spectral differences between samples picked up at two different depths (0.3 - 4 m). High discrimination percentage (90%) were found between leaf samples as function of the different depths, analyzing the spectral data by Partial Least Squares model. Forward activities will stress the system capability also to evaluate different phenol concentrations on Posidonia leaves, an important index of physiologic vegetal damage, through direct underwater spectrophotometric monitoring.

  4. Ecohydrology of an Embanked Lowland UK River Meadow and the Effects of Embankment Removal

    NASA Astrophysics Data System (ADS)

    Clilverd, H.; Thompson, J.; Sayer, C.; Heppell, K.; Axmacher, J.

    2012-12-01

    Pristine riparian and floodplain ecosystems are in a state of dynamic balance due to the regular floods that continuously reshape river channels and their banks, and transport water, sediment and nutrients onto the floodplain. However, the natural flow regime of many rivers has been altered by channelization and artificial embankments designed to protect agricultural and urban developments from flooding. This has had a lasting impact on the hydrological characteristics of floodplain ecosystems and the biological communities that inhabit them. Floodplain restoration, through embankment removal and the reconfiguration of river channels, is now being increasingly employed to re-establish river-floodplain connections and assist the recovery of lost or declining species. In order to manage a river restoration site for plant biodiversity, it is necessary to understand the physical and nutritional status of the root environment. We conducted fine scale (10 × 10 m) botanical and chemical sampling on a 3 ha embanked grassland meadow in Norfolk (Eastern England) and assessed the spatial pattern of plant communities in relation to soil physicochemical conditions. Continuous measurements of groundwater depth and river stage were collectively used to determine changes in the hydrological regime following embankment-removal. Prior to the restoration the meadow plant community was dominated by Holcus lanatus, Ranunculus repens and Agrostis stolonifera. Species richness was fairly low (mean: 8 spp. per m2), and indices of alpha-diversity suggest low heterogeneity of the plant assemblages (mean values for Shannon's Diversity and 1/Simpson's Diversity = 1.4 and 3.4, respectively). Top soils were moderately fertile, with mean respective Olsen P and plant available potassium concentrations of 9.1 mg P kg-1and 1.6 mg K+g-1. Plant available ammonium and nitrate concentrations were on average 31.7 mg NH4+-N kg-1 and 2.8 mg NO3--N kg-1, respectively. River water was enriched in nitrate

  5. Water Quality in a Wet Meadow, Platte River Valley, Central Nebraska

    USGS Publications Warehouse

    Emmons, Patrick J.

    1996-01-01

    The Platte River Valley in Nebraska, and in particular the reach from Kearney to Grand Island, is an extremely important natural habitat area. Over 300 migratory bird species, including several threatened and endangered species, have been observed along the Platte River. In the spring, nearly 500,000 sandhill cranes, along with millions of ducks and geese, use this reach as a staging and feeding area during their northerly migration. Wet meadows (grasslands which have waterlogged soils much of the year) are a critical part of this migratory-bird habitat. However, the area of wet meadows between Kearney and Grand Island has declined nearly 50 percent due to the activities of man. The condition of the remaining wet meadows is of vital importance. The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program is designed to describe the status and trends in the quality of the Nation's surface water and groundwater resources and to provide a sound understanding of the natural and human factors that affect the quality of these resources. A study of the groundwater beneath a selected wet meadow was undertaken as part of the Central Nebraska Basins NAWQA study unit. Observation wells were installed in the wet meadow at various distances along two transects downgradient from the edge of a corn field. One to five wells completed at depths of about 15 to 100 feet were located at each of the 5 sites. The wells were completed in the Platte River alluvium or the underlying Ogallala Formation. The depth to the water table ranges from 0 to 5 feet below land surface. The general direction of groundwater flow is parallel to flow in the Platte River. Selected wells were sampled in February, March, June, and December 1994 for major cations and anions, nutrients, and organonitrogen herbicides. Pesticides and fertilizers are used extensively in Nebraska to enhance the production of row crops. Some of these pesticides and fertilizers have migrated into the groundwater

  6. Effectiveness and consistency of a suite of descriptors for assessing the ecological status of seagrass meadows (Posidonia oceanica L. Delile)

    NASA Astrophysics Data System (ADS)

    Rotini, Alice; Belmonte, Alessandro; Barrote, Isabel; Micheli, Carla; Peirano, Andrea; Santos, Rui O.; Silva, João; Migliore, Luciana

    2013-09-01

    The increasing rate of human-induced environmental changes on coastal marine ecosystems has created a demand for effective descriptors, in particular for those suitable for monitoring the status of seagrass meadows. Growing evidence has supported the useful application of biochemical and genetic descriptors such as secondary metabolite synthesis, photosynthetic activity and genetic diversity. In the present study, we have investigated the effectiveness of different descriptors (traditional, biochemical and genetic) in monitoring seagrass meadow conservation status. The Posidonia oceanica meadow of Monterosso al Mare (Ligurian sea, NW Mediterranean) was subjected to the measurement of bed density, leaf biometry, total phenols, soluble protein and photosynthetic pigment content as well as to RAPD marker analysis. This suite of descriptors provided evidence of their effectiveness and convenient application as markers of the conservation status of P. oceanica and/or other seagrasses. Biochemical/genetic descriptors and those obtained by traditional methods depicted a well conserved meadow with seasonal variability and, particularly in summer, indicated a healthier condition in a portion of the bed (station C), which was in agreement with the physical and sedimentological features of the station. Our results support the usefulness of introducing biochemical and genetic approaches to seagrass monitoring programs since they are effective indicators of plant physiological stress and environmental disturbance.

  7. Changes in Meadow Vegetation Cover in Kings Canyon National Park (California) Based on Three Decades of Landsat Image Analysis

    NASA Technical Reports Server (NTRS)

    Potter, Christopher

    2015-01-01

    Landsat (30 meter resolution) image analysis over the past 25 years in Kings Canyon National Park was used to track changes in the normalized difference vegetation index (NDVI). Results showed that NDVI values from the wet year of 2010 were significantly lower than NDVI values from the comparatively dry year of 2013 in the majority of meadow areas in the National Park.

  8. AN INTEGRATED, SCIENCE-BASED APPROACH TO MANAGING AND RESTORING UPLAND RIPARIAN MEADOWS IN THE GREAT BASIN OF CENTRAL NEVADA

    EPA Science Inventory

    Riparian corridor and meadow ecosystems in upland watersheds are of local and regional importance in the Great Basin. Covering only 1-3% of the total land area, these ecosystems contain a disproportionally large percentage of the region's biodiversity. Stream incision is a major ...

  9. Comparative distribution of central neuropeptide Y (NPY) in the prairie (Microtus ochrogaster) and meadow (M. pennsylvanicus) vole.

    PubMed

    Hostetler, Caroline M; Hitchcock, Leah N; Anacker, Allison M J; Young, Larry J; Ryabinin, Andrey E

    2013-02-01

    Neuropeptide Y (NPY) has been implicated as a modulator of social behavior, often in a species-specific manner. Comparative studies of closely related vole species are particularly useful for identifying neural systems involved in social behaviors in both voles and humans. In the present study, immunohistochemistry was performed to compare NPY-like immunoreactivity (-ir) in brain tissue of the socially monogamous prairie vole and non-monogamous meadow vole. Species differences in NPY-ir were observed in a number of regions including the cortex, extended amygdala, septal area, suprachiasmatic nucleus, and intergeniculate leaf. Meadow voles had higher NPY-ir in all these regions as compared to prairie voles. No differences were observed in the striatum or hippocampus. The extended amygdala and lateral septum are regions that play a key role in regulation of monogamous behaviors such as pair bonding and paternal care. The present study suggests NPY in these regions may be an additional modulator of these species-specific social behaviors. Meadow voles had moderately higher NPY-ir in a number of hypothalamic regions, especially in the suprachiasmatic nucleus. Meadow voles also had much higher levels of NPY-ir in the intergeniculate leaflet, another key region in the regulation of circadian rhythms. Overall, species differences in NPY-ir were observed in a number of brain regions implicated in emotion, stress, circadian, and social behaviors. These findings provide additional support for a role for the NPY system in species-typical social behaviors.

  10. SUBSURFACE CHARACTERIZATION OF UPLAND RIPARIAN MEADOWS IN CENTRAL NEVADA USING AN INNOVATIVE DIRECT-PUSH EXPLORATION RIG

    EPA Science Inventory

    The U.S. EPA and the USDA Forest Service are conducting a joint investigation to better understand the interactions between geomorphology, hydrology, and vegetation associated with riparian meadow ecosystems in upland watersheds in central Nevada. Stream incision is a major threa...

  11. Species differences in behavior and cell proliferation/survival in the adult brains of female meadow and prairie voles.

    PubMed

    Pan, Y; Liu, Y; Lieberwirth, C; Zhang, Z; Wang, Z

    2016-02-19

    Microtine rodents display diverse patterns of social organization and behaviors, and thus provide a useful model for studying the effects of the social environment on physiology and behavior. The current study compared the species differences and the effects of oxytocin (OT) on anxiety-like, social affiliation, and social recognition behaviors in female meadow voles (Microtus pennsylvanicus) and prairie voles (Microtus ochrogaster). Furthermore, cell proliferation and survival in the brains of adult female meadow and prairie voles were compared. We found that female meadow voles displayed a higher level of anxiety-like behavior but lower levels of social affiliation and social recognition compared to female prairie voles. In addition, meadow voles showed lower levels of cell proliferation (measured by Ki67 staining) and cell survival (measured by BrdU staining) in the ventromedial hypothalamus (VMH) and amygdala (AMY), but not the dentate gyrus of the hippocampus (DG), than prairie voles. Interestingly, the numbers of new cells in the VMH and AMY, but not DG, also correlated with anxiety-like, social affiliation, and social recognition behaviors in a brain region-specific manner. Finally, central OT treatment (200 ng/kg, icv) did not lead to changes in behavior or cell proliferation/survival in the brain. Together, these data indicate a potential role of cell proliferation/survival in selected brain areas on different behaviors between vole species with distinct life strategies. PMID:26708743

  12. GEOMORPHIC CONTROLS ON MEADOW ECOSYSTEMS – INSIGHTS INTO LOCAL PROCESSES USING NEAR-SURFACE SEISMIC TECHNIQUES AND GROUND PENETRATING RADAR

    EPA Science Inventory

    Geomorphic controls on riparian meadows in the Central Great Basin of Nevada are an important aspect in determining the formation of and planning the management of these systems. The current hypothesis is that both alluvial fan sediment and faulted bedrock steps interact to cont...

  13. Can nutrients alone shift a sedge meadow towards dominance by the invasive Typha × glauca

    USGS Publications Warehouse

    Woo, Isa; Zedler, Joy B.

    2002-01-01

    Where wetlands receive urban runoff, Typha spp. and other invasive plants often displace the native vegetation. We tested the ability of nutrients (N and P) to increase vegetative growth of T. × glauca(a hybrid of T. latifolia and T. angustifolia). In the greenhouse, 17 treatments revealed that T. × glauca required both N and P for growth, and total leaf length was most stimulated where a higher proportion of P was added (7N∶1P vs. 14N∶1P, with N constant and P changed), regardless of concentration (the High treatment was 4× the Low treatment). In Gardner Marsh (Madison, Wisconsin, USA), we set up 28 plots (1×6 m) that bisected the boundary between sedge meadow (graminoids) and T. × glauca, and we added a common lawn fertilizer (9N∶1P∶4K) at high (62.5 g/m2), medium (31.3 g/m2), low (15.6 g/m2), and control (0 g/m2) rates on five dates, with n=7 plots/treatment. After one growing season, fertilizer addition increased T. × glauca ramet density, height, and biomass, especially where the sedge meadow graminoids were initially dominant. Aboveground biomass of T. × glauca in the high nutrient addition treatment (1029±256.1 g/m2) was more than double that for control plots (431±80.52 g/m2) overall, with the greatest percent increase in sedge meadow subplots. In contrast, native graminoids (mostly Carex spp.) did not respond to treatment, either in biomass or percent cover. Typha × glauca allocated nutrients to both growth and storage, as indicated by higher N and P concentrations in leaves, shoot bases, and rhizomes in plots with high nutrient addition. Because fertilizing the marsh enhanced the shoot growth of T. × glauca but not native graminoids, and because the 7N∶1P treatment stimulated growth in the greenhouse, we suggest that wetland managers focus on reducing P inflows to urban wetlands. Fertilizer additions below those recommended by the manufacturer for new lawns (5× that of our highest treatment) should be more

  14. Geothermal Prospecting using Hyperspectral Imaging and Field Observations, Dixie Meadows, NV

    SciTech Connect

    Kennedy-Bowdoin, T; Silver, E; Martini, B; Pickles, W

    2004-04-26

    In an ongoing project to relate surface hydrothermal alteration to structurally controlled geothermal aquifers, we mapped a 16 km swath of the eastern front of the Stillwater Range using Hyperspectral fault and mineral mapping techniques. The Dixie Valley Fault system produces a large fractured aquifer heating Pleistocene aged groundwater to a temperature of 285 C at 5-6 km. Periodically over the last several thousand years, seismic events have pushed these heated fluids to the surface, leaving a rich history of hydrothermal alteration in the Stillwater Mountains. At Dixie Hot Springs, the potentiometric surface of the aquifer intersects the surface, and 75 C waters flow into the valley. We find a high concentration of alunite, kaolinite, and dickite on the exposed fault surface directly adjacent to a series of active fumaroles on the range front fault. This assemblage of minerals implies interaction with water in excess of 200 C. Field spectra support the location of the high temperature mineralization. Fault mapping using a Digital Elevation Model in combination with mineral lineation and field studies shows that complex fault interactions in this region are improving permeability in the region leading to unconfined fluid flow to the surface. Seismic studies conducted 10 km to the south of Dixie Meadows show that the range front fault dips 25-30 to the southeast (Abbott et al., 2001). At Dixie Meadows, the fault dips 35 to the southeast, demonstrating that this region is part of the low angle normal fault system that produced the Dixie Valley Earthquake in 1954 (M=6.8). We conclude that this unusually low angle faulting may have been accommodated by the presence of heated fluids, increasing pore pressure within the fault zone. We also find that younger synthetic faulting is occurring at more typical high angles. In an effort to present these findings visually, we created a cross-section, illustrating our interpretation of the subsurface structure and the

  15. Effects of Reduced Summer Precipitation on Productivity and Forage Quality of Floodplain Meadows at the Elbe and the Rhine River

    PubMed Central

    Ludewig, Kristin; Donath, Tobias W.; Zelle, Bianka; Eckstein, R. Lutz; Mosner, Eva; Otte, Annette; Jensen, Kai

    2015-01-01

    Background Floodplain meadows along rivers are semi-natural habitats and depend on regular land use. When used non-intensively, they offer suitable habitats for many plant species including rare ones. Floodplains are hydrologically dynamic ecosystems with both periods of flooding and of dry conditions. In German floodplains, dry periods may increase due to reduced summer precipitation as projected by climate change scenarios. Against this background, the question arises, how the forage quantity and quality of these meadows might change in future. Methods We report results of two field trials that investigated effects of experimentally reduced summer precipitation on hay quantity and quality of floodplain meadows at the Rhine River (2011-2012) and at two Elbe tributaries (2009-2011). We measured annual yield, the amount of hay biomass, and contents of crude protein, crude fibre, energy, fructan, nitrogen, phosphorus, and potassium. Results The annual yield decreased under precipitation reduction at the Rhine River. This was due to reduced productivity in the second cut hay at the Rhine River in which, interestingly, the contents of nitrogen and crude protein increased. The first cut at the Rhine River was unaffected by the treatments. At the Elbe tributaries, the annual yield and the hay quantity and quality of both cuts were only marginally affected by the treatments. Conclusion We conclude that the yield of floodplain meadows may become less reliable in future since the annual yield decreased under precipitation reduction at the Rhine River. However, the first and agriculturally more important cut was almost unaffected by the precipitation reduction, which is probably due to sufficient soil moisture from winter/spring. As long as future water levels of the rivers will not decrease during spring, at least the use of the hay from the first cut of floodplain meadows appears reliable under climate change. PMID:25950730

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

    USGS Publications Warehouse

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

    2008-01-01

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

  17. Oregon Spotted Frog (Rana pretiosa) movement and demography at Dilman Meadow: implications for future monitoring

    USGS Publications Warehouse

    Chelgren, Nathan D.; Pearl, Christopher A.; Bowerman, Jay; Adams, Michael J.

    2007-01-01

    Introduction The Oregon spotted frog (Rana pretiosa) is a highly aquatic frog that has been extirpated from a large portion of its historic range in the Pacific Northwest, and remaining populations are reduced and isolated (Hayes 1997, Pearl and Hayes 2005). Loss and alteration of marsh habitat, predation and competition from exotic fish and bullfrogs, and degraded water quality from agriculture and livestock grazing are implicated in their decline (Hayes 1997, Pearl and Hayes 2005). In 2001, an interagency team translocated a population of frogs from a site that was to be eliminated by the renovation of the dam impounding Wickiup Reservoir, to newly created ponds at Dilman Meadow (121i?? 39' 52" W, 43i?? 41' 58" N), 2.5 km from the original site in central Oregon, USA. We monitored Oregon spotted frog demography and movements at Dilman Meadow for > 4 yr to assess the efficacy of these mitigation efforts, determine metrics for long-term monitoring, and inform future management at the site. More broadly, many aspects of Oregon spotted frog life history are poorly known, so understanding demography and movement patterns is likely to be useful in its conservation. Although wildlife translocations have been attempted extensively as conservation means, few such projects have been sufficiently monitored for demographic rates to understand the causes for the translocation's success or failure (Dodd and Seigel 1991). Our objective here is to document demographic and movement patterns in the population of Oregon spotted frog at Dilman Meadow so that this information will be available to guide management decisions. To better evaluate amphibian population responses to management actions it is important to consider the contribution of each life history stage and both genders to the balance of reproduction and mortality. Population growth or contraction occurs as a complicated function of the probability of breeding, fecundity, and survival during multiple life history stages

  18. Paenibacillus tibetensis sp. nov., a psychrophilic bacterium isolated from alpine swamp meadow soil.

    PubMed

    Han, Li-Li; He, Ji-Zheng; Zheng, Yuan-Ming; Zeng, Jun; Zhang, Li-Mei

    2015-05-01

    A novel psychrophilic strain, SSB001(T), was isolated from an alpine swamp meadow soil in Tibet, China, and identified as a representative of a novel phylogenetic subclade in the genus Paenibacillus , with Paenibacillus antarcticus (96.2%), Paenibacillus macquariensis (96.53%) and Paenibacillus glacialis (96.2%) as the most closely related species on the basis of 16S rRNA gene sequence analyses. The strain was distinguished from defined species of the genus Paenibacillus by further study of rpoB gene sequences, phenotypic characterization, cellular fatty acid composition, quinones, polar lipids and meso-diaminopimelic acid in the peptidoglycan. Based upon these results, we propose the strain as a representative of a novel species named Paenibacillus tibetensis sp. nov., with SSB001(T) ( =ACCC 19728(T) =DSM 29321(T)) as the type strain. The DNA G+C content (mol%) of strain SSB001(T) was 40.18 mol% (HPLC).

  19. Case Study: Mobile Photovoltaic System at Bechler Meadows Ranger Station, Yellowstone National Park

    SciTech Connect

    Andy Walker

    2014-03-05

    The mobile PV/generator hybrid system deployed at Bechler Meadows provides a number of advantages. It reduces on-site air emissions from the generator. Batteries allow the generator to operate only at its rated power, reducing run-time and fuel consumption. Energy provided by the solar array reduces fuel consumption and run-time of the generator. The generator is off for most hours providing peace and quiet at the site. Maintenance trips from Mammoth Hot Springs to the remote site are reduced. The frequency of intrusive fuel deliveries to the pristine site is reduced. And the system gives rangers a chance to interpret Green Park values to the visiting public. As an added bonus, the system provides all these benefits at a lower cost than the basecase of using only a propane-fueled generator, reducing life cycle cost by about 26%.

  20. Case Study: Mobile Photovoltaic System at Bechler Meadows Ranger Station, Yellowstone National Park (Brochure)

    SciTech Connect

    Not Available

    2014-03-01

    The mobile PV/generator hybrid system deployed at Bechler Meadows provides a number of advantages. It reduces on-site air emissions from the generator. Batteries allow the generator to operate only at its rated power, reducing run-time and fuel consumption. Energy provided by the solar array reduces fuel consumption and run-time of the generator. The generator is off for most hours providing peace and quiet at the site. Maintenance trips from Mammoth Hot Springs to the remote site are reduced. The frequency of intrusive fuel deliveries to the pristine site is reduced. And the system gives rangers a chance to interpret Green Park values to the visiting public. As an added bonus, the system provides all these benefits at a lower cost than the basecase of using only a propane-fueled generator, reducing life cycle cost by about 26%.

  1. Air Quality Scoping Study for Ash Meadows National Wildlife Refuge, Nevada (EMSI April 2007)

    SciTech Connect

    Engelbrecht, Johann; Kavouras, Ilias; Campbell, Dave; Campbell, Scott; Kohl, Steven; Shafer, David

    2007-04-01

    The Desert Research Institute (DRI) is performing a scoping study as part of the U.S.Department of Energy’s Yucca Mountain Environmental Monitoring Systems Initiative (EMSI). The main objective is to obtain baseline air quality information for Yucca Mountain and an area surrounding the Nevada Test Site (NTS). Air quality and meteorological monitoring and sampling equipment housed in a mobile trailer (shelter) is collecting data at seven sites outside the NTS, including Ash Meadows National Wildlife Refuge, Sarcobatus Flat, Beatty, Rachel, Caliente, Pahranagat National Wildlife Refuge, and Crater Flat, and at four sites on the NTS. The trailer is stationed at any one site for approximately eight weeks at a time. Letter reports provide summaries of air quality and meteorological data, on completion of each site’s sampling program.

  2. Pineal and photoperiodic influences on fat deposition, pelage, and testicular activity in male meadow voles.

    PubMed

    Smale, L; Dark, J; Zucker, I

    1988-01-01

    Pinealectomy completely prevented gonadal regression as well as reduction in body weight and white adipose tissue content of the gonadal and retroperitoneal fat deposits in male meadow voles transferred from long to short day lengths. Pineal influences on pelage characteristics depended on which parameter was assessed. For instance, the increase in guard hair length observed in short-day control voles was blocked by pinealectomy; however, a similar increase in underhair length was unaffected by removal of the pineal gland. Photoperiod-dependent changes in fat deposition, testicular activity, and guard hair length presumably rely on altered pineal secretory activity to transduce the effects of day length on the neuroendocrine axis; however, mechanisms independent of pineal activity may be capable of mediating photoperiodic control of underhair growth. PMID:2979644

  3. Photoperiod and gonadal hormones influence odor preferences of the male meadow vole, Microtus pennsylvanicus.

    PubMed

    Ferkin, M H; Gorman, M R

    1992-05-01

    Male meadow voles housed in a long photoperiod (14 h light/day, LP) preferred female to male odors, whereas males maintained in a short photoperiod (10 h light/day, SP) did not display preferences for odors of either sex. These odor-preference patterns matched those of free-living males during spring and autumn, respectively. The preference of LP male voles for female over male odors was eliminated by gonadectomy and reinstated by treatment with testosterone. In SP males, although gonadectomy did not affect odor choices, a preference for female odors was induced by testosterone treatment. Treatment with estradiol did not alter odor preferences of LP or SP males. In conjunction with previous result, the present findings suggest that hormonal responsiveness of neural substrates that control odor preferences are sexually dimorphic and may reflect sex differences in reproductive strategies. PMID:1615048

  4. Seasonal control of odour preferences of meadow voles (Microtus pennsylvanicus) by photoperiod and ovarian hormones.

    PubMed

    Ferkin, M H; Zucker, I

    1991-07-01

    During the spring-summer breeding season, female meadow voles prefer odours of males over those of females, but in the autumn-winter season of reproductive quiescence this preference is reversed. Females housed in long (14 h light/day) and short (10 h light/day) photoperiods, respectively, had odour preferences comparable to those of spring and autumn voles, respectively. The preference of long-photoperiod voles for male over female odours was reversed by ovariectomy and restored by treatment with oestradiol. By contrast, neither ovariectomy nor oestradiol affected odour preferences of short-photoperiod voles. Long days appear to influence olfactory preferences by altering ovarian hormone secretion. The failure of oestradiol to affect odour preferences in short photoperiods suggests that the neural substrates mediating this behavioural response are refractory to oestrogens during the nonbreeding season. PMID:1886099

  5. Welcome mats? The role of seagrass meadow structure in controlling post-settlement survival in a keystone sea-urchin species

    NASA Astrophysics Data System (ADS)

    Prado, Patricia; Romero, Javier; Alcoverro, Teresa

    2009-11-01

    Processes acting on the early-life histories of marine organisms can have important consequences for the structuring of benthic communities. In particular, the degree of coupling between larval supply and adult abundances can wield considerable influence on the strength of trophic interactions in the ecosystem. These processes have been relatively well described in rocky systems and soft-sediment communities, and it is clear that they are governed by very different bottlenecks. Seagrass meadows make interesting study systems because they bear structural affinities to both soft sediments as well as rocky substrates. We examined the early-life history of Paracentrotus lividus, one of the dominant herbivores in Mediterranean seagrass meadows, to identify the drivers of population dynamics in this species. We measured spatial and temporal variability in sea urchin post-settlement in 10 Posidonia oceanica meadows in the North-Western Mediterranean over a period of two years, and compared the numbers with the one-year old cohort a year later (i.e. the new population recruitment) as well as between successive size-age groups. Urchin post-settlers differed substantially between meadows but were present in both years in all meadows surveyed, suggesting that larval supply was not limiting for any of the studied sites. However, in six of the studied meadows, the one-year cohort of urchins was absent in both years, indicating that post-settlement processes strongly affected urchins in these meadows. In contrast, in four of the studied meadows, there was a strong coupling between post-settlers and one-year cohort individuals. These meadows were structurally different from the others in that they were characterised by an exposed matrix of rhizomes forming a dense seagrass mat. This mat apparently strongly mediates post-settlement mortality, and its presence or absence dictates the successful establishment of urchin populations in seagrass meadows. As the population aged, the

  6. Comparative toxicity of acephate in laboratory mice, white-footed mice and meadow voles

    USGS Publications Warehouse

    Rattner, B.A.; Hoffman, D.J.

    1983-01-01

    The LD50 (95% confidence limits) of the organophosphorus insecticide acephate was estimated to be 351, 380, and 321 mg/kg (295?416, 280?516, and 266?388 mg/kg) for CD-1 laboratory mice (Mus musculus), white-footed mice (Peromyscus leucopus noveboracensis), and meadow voles (Microtus pennsylvanicus), respectively. In a second study, these species were provided mash containing 0, 25, 100, and 400 ppm acephate for five days. Brain and plasma cholinesterase activities were reduced in a dose-dependent manner to a similar extent in the three species (inhibition of brain acetyl-cholinesterase averaged for each species ranged from 13 to 22% at 25 ppm, 33 to 42% at 100 ppm, and 56 to 57% at 400 ppm). Mash intake, body or liver weight, plasma enzyme activities (alkaline phosphatase, alanine and aspartate aminotransferase), hepatic enzyme activities (aniline hydroxylase, 7-ethoxycoumarin O-deethylase, and glutathione S-transferase), and cytochrome content (P-450 and b5) were not affected by acephate ingestion, although values differed among species. In a third experiment, mice and voles received 400 ppm acephate for 5 days followed by untreated food for up to 2 weeks. Mean inhibition of brain acetylcholin-esterase for the three species ranged from 47 to 58% on day 5, but by days 12 and 19, activity had recovered to 66 to 76% and 81 to 88% of concurrent control values. These findings indicate that CD-1 laboratory mice, white-footed mice, and meadow voles are equally sensitive to acephate when maintained under uniform laboratory conditions. Several factors (e.g., behavior, food preference, habitat) could affect routes and degree of exposure in the field, thereby rendering some species of wild rodents ecologically more vulnerable to organophosphorus insecticides.

  7. Comparative toxicity of acephate in laboratory mice, white-footed mice, and meadow voles

    USGS Publications Warehouse

    Rattner, B.A.; Hoffman, D.J.

    1984-01-01

    The LD50 (95% confidence limits) of the organophosphorus insecticide acephate was estimated to be 351, 380, and 321 mg/kg (295?416, 280?516, and 266?388 mg/kg) for CD-1 laboratory mice (Mus musculus), white-footed mice (Peromyscus leucopus noveboracensis), and meadow voles (Microtus pennsylvanicus), respectively. In a second study, these species were provided mash containing 0, 25, 100, and 400 ppm acephate for five days. Brain and plasma cholinesterase activities were reduced in a dose-dependent manner to a similar extent in the three species (inhibition of brain acetyl-cholinesterase averaged for each species ranged from 13 to 22% at 25 ppm, 33 to 42% at 100 ppm, and 56 to 57% at 400 ppm). Mash intake, body or liver weight, plasma enzyme activities (alkaline phosphatase, alanine and aspartate aminotransferase), hepatic enzyme activities (aniline hydroxylase, 7-ethoxycoumarin O-deethylase, and glutathione S-transferase), and cytochrome content (P-450 and b5) were not affected by acephate ingestion, although values differed among species. In a third experiment, mice and voles received 400 ppm acephate for 5 days followed by untreated food for up to 2 weeks. Mean inhibition of brain acetylcholin-esterase for the three species ranged from 47 to 58% on day 5, but by days 12 and 19, activity had recovered to 66 to 76% and 81 to 88% of concurrent control values. These findings indicate that CD-1 laboratory mice, white-footed mice, and meadow voles are equally sensitive to acephate when maintained under uniform laboratory conditions. Several factors (e.g., behavior, food preference, habitat) could affect routes and degree of exposure in the field, thereby rendering some species of wild rodents ecologically more vulnerable to organophosphorus insecticides.

  8. Warming and Nitrogen Addition Alter Photosynthetic Pigments, Sugars and Nutrients in a Temperate Meadow Ecosystem

    PubMed Central

    Zhang, Tao; Yang, Shaobo; Guo, Rui; Guo, Jixun

    2016-01-01

    Global warming and nitrogen (N) deposition have an important influence on terrestrial ecosystems; however, the influence of warming and N deposition on plant photosynthetic products and nutrient cycling in plants is not well understood. We examined the effects of 3 years of warming and N addition on the plant photosynthetic products, foliar chemistry and stoichiometric ratios of two dominant species, i.e., Leymus chinensis and Phragmites communis, in a temperate meadow in northeastern China. Warming significantly increased the chlorophyll content and soluble sugars in L. chinensis but had no impact on the carotenoid and fructose contents. N addition caused a significant increase in the carotenoid and fructose contents. Warming and N addition had little impact on the photosynthetic products of P. communis. Warming caused significant decreases in the N and phosphorus (P) concentrations and significantly increased the carbon (C):P and N:P ratios of L. chinensis, but not the C concentration or the C:N ratio. N addition significantly increased the N concentration, C:P and N:P ratios, but significantly reduced the C:N ratio of L. chinensis. Warming significantly increased P. communis C and P concentrations, and the C:N and C:P ratios, whereas N addition increased the C, N and P concentrations but had no impact on the stoichiometric variables. This study suggests that both warming and N addition have direct impacts on plant photosynthates and elemental stoichiometry, which may play a vital role in plant-mediated biogeochemical cycling in temperate meadow ecosystems. PMID:27171176

  9. Modelling the effects of Zostera noltei meadows on sediment dynamics: application to the Arcachon lagoon

    NASA Astrophysics Data System (ADS)

    Kombiadou, Katerina; Ganthy, Florian; Verney, Romaric; Plus, Martin; Sottolichio, Aldo

    2014-10-01

    A three-dimensional model has been modified to describe the complex interactions between hydrodynamics, sediment dynamics and biological parameters in the presence of Zostera noltei. The model treats seagrass leafs as flexible blades that bend under hydrodynamic forcing and alter the local momentum and turbulence fluxes and, therefore, the benthic shear conditions; these changes cause related changes to the mass balance at the boundary of the bed, in turn affecting the suspended matter in the column and ultimately primary productivity and the growth of the dwarf-grass. Modelling parameters related to the impact of Z. noltei to the local flow and to erosion and deposition rates were calibrated using flume experimental measurements; results from the calibration of the model are presented and discussed. The coupled model is applied in the Arcachon Bay, an area with high environmental significance and large abundance of dwarf-grass meadows. In the present paper, results from preliminary applications of the model are presented and discussed; the effectiveness of the coupled model is assessed comparing modelling results with available field measurements of suspended sediment concentrations and seagrass growth parameters. The model generally reproduces sediment dynamics and dwarf-grass seasonal growth in the domain efficiently. Investigations regarding the effects of the vegetation to the near-bed hydrodynamics and to the sediment suspension in the domain show that dwarf-grass meadows play an important part to velocity attenuation and to sediment stabilisation, with flow and suspended sediment concentrations damping, compared to an unvegetated state, to reach 35-50 and 65 %, respectively, at peak seagrass growth.

  10. Water-resources data collected in the Devils Hole area, Ash Meadows, Nevada, 1975-76

    USGS Publications Warehouse

    Hanes, William Toby

    1976-01-01

    The U.S. Geological Survey collected water-level, spring-flow, and power-consumption data in the Devils Hole area in Nevada from July 1975 through June 1976. The work for this sfurth annual data report was done in cooperation with the National Park Service. Continuous recorders were used to monitor water levels in Devils Hole, three observation wells, and the flow from four springs. Also, monthly readings were made on two wells to help define a general trend of ground-water levels. Monthly meter readings of six electrically powered irrigation wells provided a record of power consumption, which in turn, is an index of the amount of water pumped. The purpose of the work is to observe the effects, if any, of ground-water withdrawals from specified irrigtion wells in the Ash Meadows area on (1) the water level in Devils Hole, and (2) the flow of four springs in the area. Fairbanks Spring and Big Spring, which are in the extreme northern and southern parts of Ash Meadows respectively, show little effect of pumping. An increase in the monthly average flow at Fairbanks Spring in September can be attributed to runoff and surficial recharge in the surrounding area caused by a large cloudburst. Jack Rabbit Spring, which is about 1 mile southwest of the major pumping field, is affected strongly by pumping. Jack Rabbit Spring flowed during the winter months but flowed very infrequently during non-winter months. Point of Rocks Spring had a flow pattern similar to Big Spring and Fairbanks Spring. All the springs had a general increase in flow during the Winter months. (Woodard-USGS)

  11. Warming and Nitrogen Addition Alter Photosynthetic Pigments, Sugars and Nutrients in a Temperate Meadow Ecosystem.

    PubMed

    Zhang, Tao; Yang, Shaobo; Guo, Rui; Guo, Jixun

    2016-01-01

    Global warming and nitrogen (N) deposition have an important influence on terrestrial ecosystems; however, the influence of warming and N deposition on plant photosynthetic products and nutrient cycling in plants is not well understood. We examined the effects of 3 years of warming and N addition on the plant photosynthetic products, foliar chemistry and stoichiometric ratios of two dominant species, i.e., Leymus chinensis and Phragmites communis, in a temperate meadow in northeastern China. Warming significantly increased the chlorophyll content and soluble sugars in L. chinensis but had no impact on the carotenoid and fructose contents. N addition caused a significant increase in the carotenoid and fructose contents. Warming and N addition had little impact on the photosynthetic products of P. communis. Warming caused significant decreases in the N and phosphorus (P) concentrations and significantly increased the carbon (C):P and N:P ratios of L. chinensis, but not the C concentration or the C:N ratio. N addition significantly increased the N concentration, C:P and N:P ratios, but significantly reduced the C:N ratio of L. chinensis. Warming significantly increased P. communis C and P concentrations, and the C:N and C:P ratios, whereas N addition increased the C, N and P concentrations but had no impact on the stoichiometric variables. This study suggests that both warming and N addition have direct impacts on plant photosynthates and elemental stoichiometry, which may play a vital role in plant-mediated biogeochemical cycling in temperate meadow ecosystems.

  12. Lower Red River Meadow Restoration Project : Biennial Report 1996-97.

    SciTech Connect

    LRK Communications; Wildlife Habitat Institute; Pocket Water, Inc.

    2003-07-01

    The Red River has been straightened and the riparian vegetation corridor eliminated in several reaches within the watershed. The river responded by incision resulting in over-steepened banks, increased sedimentation, elevated water temperatures, depressed groundwater levels, reduced floodplain function, and degraded fish habitat. The Lower Red River Meadow Restoration Project is a multi-phase ecosystem enhancement effort that restores natural physical and biological processes and functions to stabilize the stream channel and establish high quality habitats for fish and wildlife. A natural channel restoration philosophy guides the design and on the ground activities, allowing the channel to evolve into a state of dynamic equilibrium. Two years of planning, two years of restoration in Phases I and II, and one year post-restoration monitoring are complete. By excavating new bends and reconnecting historic meanders, Phase I and II channel realignment increased channel length by 3,060 feet, decreased channel gradient by 25 percent, and increased sinuosity from 1.7 to 2.3. Cross-sectional shapes and point bars were modified to maintain deep pool habitat at low flow and to reconnect the meadow floodplain. Improved soil moisture conditions will help sustain the 31,500 native riparian plantings reestablished within these two phases. Overall, short-term restoration performance was successful. Analyses of long-term parameters document either post-restoration baseline conditions or early stages of evolution toward desired conditions. An adaptive management strategy has helped to improve restoration designs, methods, and monitoring. Lessons learned are being transferred to a variety of audiences to advance the knowledge of ecological restoration and wise management of watersheds.

  13. Potential environmental effects of pack stock on meadow ecosystems of the Sierra Nevada, USA

    USGS Publications Warehouse

    Ostoja, Steven M.; Brooks, Matthew L.; Moore, Peggy E.; Berlow, Eric L.; Robert Blank,; Roche, Jim; Chase, Jennifer T.; Sylvia Haultain,

    2014-01-01

    Pack and saddle stock, including, but not limited to domesticated horses, mules, and burros, are used to support commercial, private and administrative activities in the Sierra Nevada. The use of pack stock has become a contentious and litigious issue for land management agencies in the region inter alia due to concerns over effects on the environment. The potential environmental effects of pack stock on Sierra Nevada meadow ecosystems are reviewed and it is concluded that the use of pack stock has the potential to influence the following: (1) water nutrient dynamics, sedimentation, temperature, and microbial pathogen content; (2) soil chemistry, nutrient cycling, soil compaction and hydrology; (3) plant individuals, populations and community dynamics, non-native invasive species, and encroachment of woody species; and (4) wildlife individuals, populations and communities. It is considered from currently available information that management objectives of pack stock should include the following: minimise bare ground, maximise plant cover, maintain species composition of native plants, minimise trampling, especially on wet soils and stream banks, and minimise direct urination and defecation by pack stock into water. However, incomplete documentation of patterns of pack stock use and limited past research limits current understanding of the effects of pack stock, especially their effects on water, soils and wildlife. To improve management of pack stock in this region, research is needed on linking measurable monitoring variables (e.g. plant cover) with environmental relevancy (e.g. soil erosion processes, wildlife habitat use), and identifying specific environmental thresholds of degradation along gradients of pack stock use in Sierra Nevada meadows.

  14. Warming and Nitrogen Addition Increase Litter Decomposition in a Temperate Meadow Ecosystem

    PubMed Central

    Gong, Shiwei; Guo, Rui; Zhang, Tao; Guo, Jixun

    2015-01-01

    Background Litter decomposition greatly influences soil structure, nutrient content and carbon sequestration, but how litter decomposition is affected by climate change is still not well understood. Methodology/Principal Findings A field experiment with increased temperature and nitrogen (N) addition was established in April 2007 to examine the effects of experimental warming, N addition and their interaction on litter decomposition in a temperate meadow steppe in northeastern China. Warming, N addition and warming plus N addition reduced the residual mass of L. chinensis litter by 3.78%, 7.51% and 4.53%, respectively, in 2008 and 2009, and by 4.73%, 24.08% and 16.1%, respectively, in 2010. Warming, N addition and warming plus N addition had no effect on the decomposition of P. communis litter in 2008 or 2009, but reduced the residual litter mass by 5.58%, 15.53% and 5.17%, respectively, in 2010. Warming and N addition reduced the cellulose percentage of L. chinensis and P. communis, specifically in 2010. The lignin percentage of L. chinensis and P. communis was reduced by warming but increased by N addition. The C, N and P contents of L. chinensis and P. communis litter increased with time. Warming and N addition reduced the C content and C:N ratios of L. chinensisand P. communis litter, but increased the N and P contents. Significant interactive effects of warming and N addition on litter decomposition were observed (P<0.01). Conclusion/Significance The litter decomposition rate was highly correlated with soil temperature, soil water content and litter quality. Warming and N addition significantly impacted the litter decomposition rate in the Songnen meadow ecosystem, and the effects of warming and N addition on litter decomposition were also influenced by the quality of litter. These results highlight how climate change could alter grassland ecosystem carbon, nitrogen and phosphorus contents in soil by influencing litter decomposition. PMID:25774776

  15. Habitat edges affect patterns of artificial nest predation along a wetland-meadow boundary

    NASA Astrophysics Data System (ADS)

    Suvorov, Petr; Svobodová, Jana; Albrecht, Tomáš

    2014-08-01

    Wetland habitats are among the most endangered ecosystems in the world. However, little is known about factors affecting the nesting success of birds in pristine grass-dominated wetlands. During three breeding periods we conducted an experiment with artificial ground nests to test two basic mechanisms (the matrix and ecotonal effects) that may result in edge effects on nest predation in grass-dominated wetland habitats. Whereas the matrix effect model supposes that predator penetrate from habitat of higher predator density to habitat of lower predator density, thus causing an edge effect in the latter, according to the ecotonal effect model predators preferentially use edge habitats over habitat interiors. In addition, we tested the edge effect in a wetland habitat using artificial shrub nests that simulated the real nests of small open-cup nesting passerines. In our study area, the lowest predation rates on ground nests were found in wetland interiors and were substantially higher along the edges of both wetland and meadow habitat. However, predation was not significantly different between meadow and wetland interiors, indicating that both mechanisms can be responsible for the edge effect in wetland edges. An increased predation rate along wetland edges was also observed for shrub nests, and resembled the predation pattern of real shrub nests in the same study area. Though we are not able to distinguish between the two mechanisms of the edge effect found, our results demonstrate that species nesting in wetland edges bordering arable land may be exposed to higher predation. Therefore, an increase in the size of wetland patches that would lead to a reduced proportion of edge areas might be a suitable management practice to protect wetland bird species in cultural European landscapes.

  16. Fatty acid profiles indicate the habitat of mud snails Hydrobia ulvae within the same estuary: Mudflats vs. seagrass meadows

    NASA Astrophysics Data System (ADS)

    Coelho, Helena; Lopes da Silva, Teresa; Reis, Alberto; Queiroga, Henrique; Serôdio, João; Calado, Ricardo

    2011-03-01

    Mud snails Hydrobia ulvae occupy different habitats in complex estuarine ecosystems. In order to determine if fatty acid profiles displayed by mud snails can be used to identify the habitat that they occupy within the same estuary, fatty acids of H. ulvae from one mudflat and one seagrass meadow in the Ria de Aveiro (Portugal) were analyzed and compared to those displayed by microphytobenthos (MPB), the green leaves (epiphyte-free) of Zostera noltii, as well as those exhibited by the epiphytic community colonizing this seagrass. MPB and epiphytic diatom-dominated samples displayed characteristic fatty acids, such as 16:1 n-7 and 20:5 n-3, while 18:2 n-6 and 18:3 n-3 were the dominant fatty acids in the green leaves of Z. noltii. Significant differences between the fatty acid profiles of H. ulvae specimens sampled in the mudflat and the seagrass meadow could be identified, with those from the mudflat displaying higher levels of fatty acids known to be characteristic of MPB. This result points towards the well known existence of grazing activity on MPB by mud snails. The fatty acid profiles displayed by H. ulvae inhabiting the seagrass meadows show no evidence of direct bioaccumulation of the two most abundant polyunsaturated fatty acids of Z. noltii (18:2 n-6 and 18:3 n-3) in the mud snails, which probably indicates that either these compounds can be metabolized to produce energy, used as precursors for the synthesis of essential fatty acids, or that the snails do not consume seagrass leaves at all. Moreover, the fatty acid profiles of mud snails inhabiting the seagrass meadows revealed the existence of substantial inputs from microalgae, suggesting that the epiphytic community colonizing the leaves of Z. noltii displays an important role on the diet of these organisms. This assumption is supported by the high levels of 20:5 n-3 and 22:6 n-3 recorded in mud snails sampled from seagrass meadows. In conclusion, fatty acid analyses of H. ulvae can be successfully used

  17. HYDROGEOMORPHIC SETTING, CHARACTERISTICS, AND RESPONSE TO STREAM INCISION OF MONTANA RIPARIAN MEADOWS IN THE CENTRAL GREAT BASIN--IMPLICATIONS FOR RESTORATION

    EPA Science Inventory

    Riparian wet meadow complexes in the mountains of the central Great Basin are scarce, ecologically important systems that are threatened by stream incision. An interdisciplinary group has investigated 1) the origin, characteristics, and controls on the evolution of these riparian...

  18. Urbanization and recharge in the vicinity of East Meadow Brook, Nassau County, New York, part 4. Water quality in the headwaters area, 1988-93. Water resources investigations

    SciTech Connect

    Brown, C.J.; Scorca, M.P.; Stockar, G.G.; Stumm, F.; Ku, H.F.H.

    1997-12-31

    This report (1) discusses the concentration of constituents in precipitation and stormwater in the headwaters area of East Meadow Brook, and (2) describes the extent, and depth to which ground water beneath the stream is affected by stormwater. It also relates the concentrations and loads of selected constituents, including sodium and chloride, to storm discharge and season. This is the final report from the four-part study that examined stormwater and ground water at East Meadow Brook during 1988-93.

  19. From mechanical to chemical impact of anchoring in seagrasses: The premises of anthropogenic patch generation in Posidonia oceanica meadows.

    PubMed

    Abadie, Arnaud; Lejeune, Pierre; Pergent, Gérard; Gobert, Sylvie

    2016-08-15

    Intensive anchoring of leisure boats in seagrass meadows leads to mechanical damages. This anthropogenic impact creates bare mat patches that are not easily recolonized by the plant. Several tools are used to study human impacts on the structure of seagrass meadows but they are not able to assess the indirect and long term implication of mechanical destruction. We chose to investigate the possible changes in the substrate chemistry given contrasted boat impacts. Our observations show that hydrogen sulfide concentrations remain high at 15 and 20m depth (42.6μM and 18.8μM) several months after the highest period of anchoring during the summer. Moreover, our multidisciplinary study reveals that anchoring impacts of large boats at 15 and 20m depth can potentially change the seascape structure. By taking into account both structural and chemical assessments, different managing strategies must be applied for coastal areas under anthropogenic pressures. PMID:27289285

  20. Big Spring spinedace and associated fish populations and habitat conditions in Condor Canyon, Meadow Valley Wash, Nevada

    USGS Publications Warehouse

    Jezorek, Ian G.; Connolly, Patrick J.; Munz, Carrie S.; Dixon, Chris

    2011-01-01

    Executive Summary: This project was designed to document habitat conditions and populations of native and non-native fish within the 8-kilometer Condor Canyon section of Meadow Valley Wash, Nevada, with an emphasis on Big Spring spinedace (Lepidomeda mollispinis pratensis). Other native fish present were speckled dace (Rhinichthys osculus) and desert sucker (Catostomus clarki). Big Spring spinedace were known to exist only within this drainage and were known to have been extirpated from a portion of their former habitat located downstream of Condor Canyon. Because of this extirpation and the limited distribution of Big Spring spinedace, the U.S. Fish and Wildlife Service listed this species as threatened under the Endangered Species Act in 1985. Prior to our effort, little was known about Big Spring spinedace populations or life histories and habitat associations. In 2008, personnel from the U.S. Geological Survey's Columbia River Research Laboratory began surveys of Meadow Valley Wash in Condor Canyon. Habitat surveys characterized numerous variables within 13 reaches, thermologgers were deployed at 9 locations to record water temperatures, and fish populations were surveyed at 22 individual sites. Additionally, fish were tagged with Passive Integrated Transponder (PIT) tags, which allowed movement and growth information to be collected on individual fish. The movements of tagged fish were monitored with a combination of recapture events and stationary in-stream antennas, which detected tagged fish. Meadow Valley Wash within Condor Canyon was divided by a 12-meter (m) waterfall known as Delmue Falls. About 6,100 m of stream were surveyed downstream of the falls and about 2,200 m of stream were surveyed upstream of the falls. Although about three-quarters of the surveyed stream length was downstream of Delmue Falls, the highest densities and abundance of native fish were upstream of the falls. Big Spring spinedace and desert sucker populations were highest near the

  1. Relative abundance and distribution of fishes and crayfish at Ash Meadows National Wildlife Refuge, Nye County, Nevada, 2010-11

    USGS Publications Warehouse

    Scoppettone, G.G.; Johnson, D.M.; Hereford, M.E.; Rissler, Peter; Fabes, Mark; Salgado, Antonio; Shea, Sean

    2012-01-01

    Habitat restoration that favors native species can help control non-native species (McShane and others, 2004; Scoppettone and others, 2005; Kennedy and others, 2006). Restoration of Carson Slough and its tributaries present an opportunity to promote habitat types that favor native species over non-natives. Historically, the majority of Ash Meadows spring systems were tributaries to Carson Slough. In 2007 and 2008, a survey of Ash Meadows spring systems was conducted to generate baseline information on the distribution of fishes throughout AMNWR (Scoppettone and others, 2011b). In this study, we conducted a follow-up survey with emphasis on upper Carson Slough. This permitted us to gauge the early effects of spring system restoration on fish populations and to generate further baseline data relevant to future restoration efforts. 

  2. Interactions between warming and soil moisture increase overlap in reproductive phenology among species in an alpine meadow.

    PubMed

    Zhu, Juntao; Zhang, Yangjian; Wang, Wenfeng

    2016-07-01

    Climate warming strongly influences reproductive phenology of plants in alpine and Arctic ecosystems. Here, we focus on phenological shifts caused by experimental warming in a typical alpine meadow on the Tibetan Plateau. Under soil water stress caused by warming, most plants in the alpine meadow advanced or delayed their reproductive events to be aligned with the timing of peak rainfall. As a result, warming significantly increased the temporal overlap among reproductive stages of early- and late-flowering species. In addition, we found that some species, for example the late-flowering species, were unable to produce flowers and fruits under warming with failed monsoon rains. The potentially warmer- and drier-growing seasons under climate change may similarly shift the phenological patterns and change species composition of these alpine systems. PMID:27405376

  3. Cultivation-dependent analysis of the microbial diversity associated with the seagrass meadows in Xincun Bay, South China Sea.

    PubMed

    Jiang, Yu-Feng; Ling, Juan; Wang, You-Shao; Chen, Biao; Zhang, Yan-Ying; Dong, Jun-De

    2015-10-01

    Microbial communities have largely existed in the seagrass meadows. A total of 496 strains of the bacteria in the seagrass meadows, which belonged to 50 genera, were obtained by the plate cultivation method from three sites of Xincun Bay, South China Sea. The results showed that Bacillales and Vibrionales accounted for the highest proportions of organisms in all communities. The diversity of the bacteria in the sediment was higher than that associated with seagrass. Thalassia hemperichii possessed the highest abundance of bacteria, followed by Enhalus acoroides and Cymodocea rotundata. Robust seasonal dynamics in microbial community composition were also observed. It was found that microbial activities were closely tied to the growth stage of the seagrass. The microbial distribution was the lowest in site 3. The abundance of the bacteria was linked to the interactions between bacteria and plants, the condition of plant and even the coastal water quality and the nutrition level in the sediment.

  4. From mechanical to chemical impact of anchoring in seagrasses: The premises of anthropogenic patch generation in Posidonia oceanica meadows.

    PubMed

    Abadie, Arnaud; Lejeune, Pierre; Pergent, Gérard; Gobert, Sylvie

    2016-08-15

    Intensive anchoring of leisure boats in seagrass meadows leads to mechanical damages. This anthropogenic impact creates bare mat patches that are not easily recolonized by the plant. Several tools are used to study human impacts on the structure of seagrass meadows but they are not able to assess the indirect and long term implication of mechanical destruction. We chose to investigate the possible changes in the substrate chemistry given contrasted boat impacts. Our observations show that hydrogen sulfide concentrations remain high at 15 and 20m depth (42.6μM and 18.8μM) several months after the highest period of anchoring during the summer. Moreover, our multidisciplinary study reveals that anchoring impacts of large boats at 15 and 20m depth can potentially change the seascape structure. By taking into account both structural and chemical assessments, different managing strategies must be applied for coastal areas under anthropogenic pressures.

  5. Time course of androgenic modulation of odor preferences and odor cues in male meadow voles, Microtus pennsylvanicus.

    PubMed

    Ferkin, M H

    1992-12-01

    During the breeding season, male meadow voles prefer female over male odors and females prefer male over female odors. Testosterone control of males' odor preferences and production of odors attractive to females differ. A male meadow vole's preference for female versus male odor was still evident 1 week after castration, but not 1 week later. This preference was reinstated in testosterone-treated male voles 2 weeks after the onset of hormone replacement. The attractiveness of male odors to females did not disappear until 3 weeks after castration. The attractiveness of male odors was reinstated 1 week after castrated males were treated with testosterone. The time course for the androgenic modulation of production of odors attractive to females may facilitate breeding. For example, at the end of the breeding season males may emit an odor that is still attractive to females. Similarly, at the beginning of the breeding season males may emit an odor that is attractive to females. PMID:1478635

  6. Carbon balance of a subarctic meadow under 3 r{ C warming - unravelling respiration}

    NASA Astrophysics Data System (ADS)

    Silvennoinen, Hanna; Bárcena, Téresa G.; Moni, Christophe; Szychowski, Marcin; Rajewicz, Paulina; Höglind, Mats; Rasse, Daniel P.

    2016-04-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, as the warming is expected to be disproportionate as compared to world averages. Northern areas contain large terrestrial carbon (C) stocks further increasing the interest in the C cycle's fate in changing climate. In 2013, we started an ecosystem warming experiment at a meadow in Eastern Finnmark, NE Norway. The meadow was on a clay soil and its vegetation was common meadow grasses and clover. Typical local agronomy was applied. The study site featured ten 4m-wide hexagonal plots, five control and five actively warmed plots in randomized complete block design. Each of the warmed plots was continuously maintained 3 ° C above its associated control plot with infrared heaters controlled by canopy thermal sensors. In 2014-2015, we measured net ecosystem exchange (NEE) and respiration twice per week during growth seasons from preinstalled collars of each site with dynamic, temperature-controlled chambers combined to an infrared analyzer. Despite warming-induced differences in yield, species composition and root biomass, neither the NEE nor the respiration responded to the warming, all sites remaining equal sinks for C. Following this observation, we carried out an additional experiment in 2015 where we aimed at partitioning the total CO2 flux to microbial and plant respiration as well as at recording the growth season variation of those parameters in situ. Here, we used an approach based on natural abundances of 13C. The δ13C signature of both autotrophic plant respiration and heterotrophic microbial respiration were obtained in targeted incubations (Snell et al. 2014). Then, the δ13C -signature of the total soil respiration was determined in the field by Keeling approach with dynamic dark chambers combined to CRDS. Proportions of autotrophic and heterotrophic components in total soil respiration were then derived based on 13C mixing model. Incubations were repeated at early, mid and

  7. Use of seagrass meadows as an adaptation measure to climate change for reducing port agitation

    NASA Astrophysics Data System (ADS)

    Sánchez-Arcilla, Agustín; Lin, Jue; Pau Sierra, Joan; Gracia, Vicenç; Casas-Prat, Merce; Virgili, Marc

    2014-05-01

    One of the best-known consequences of the greenhouse effect and the resulting global warming is sea-level rise. However, sea level rise is not the only process of concern to coastal communities. The greenhouse effect and the complex interactions in atmospheric processes is expected to produce changes in near-surface wind and pressure patterns, which in turn can affect the pattern of another important coastal driver: the wave field. Changes in wave conditions can affect the wave pattern within harbours as shown by Casas-Prat and Sierra (2012), increasing port agitation and, as a consequence, reducing the safety and comfort of the users, decreasing operation performance or even generating port inactivity. This effect will be enhanced by an increase in mean sea level. To avoid costly structural measure there are "green" options such as sea-grass that can attenuate wave energy (Koftis et al., 2013), since their roots induce sea bottom roughness and their stems and leaves increase the drag coefficient. The combined effect of vegetation is, thus, to create drag forces that dissipate part of the energy from incoming waves. Casas-Prat and Sierra (2013) showed that wave patterns may change in the future in certain areas of the Catalan Coast (northwestern Mediterranean) and as a consequence port agitation could be affected by changes in wave height or direction as well in those areas. The suggested "green" measures can help to prevent potential negative effects on port operations. The adaptive approach, depending on the downscaled climatic projections, would combine vegetation (as for example the existence of a sea-grass meadow in the vicinity of the harbour entrance) with some structural reinforcement if required. In this paper, the wave projections of Casas-Prat and Sierra (2013) are used together with a Boussinesq-type model to study wave propagation in several harbours of the Catalan Coast. This analysis of harbour oscillations is carried out for present conditions and

  8. Micrometeorological data for energy-budget studies near Rogers Spring, Ash Meadows National Wildlife Refuge, Nye County, Nevada, 1994

    USGS Publications Warehouse

    Nichols, W.D.; Rapp, T.R.

    1996-01-01

    Micrometeorological data were collected at two sites near Rogers Spring in the Ash Meadows National Wildlife Refuge for use in energy-budget studies beginning in 1994. The data collected at each site included net radiation, air temperature at two heights, dew-point temperature at two heights, windspeed at two heights, soil heat flux, and soil temperature in the interval between the land surface and the buried heat-flux plates.

  9. Does the different mowing regime affect soil biological activity and floristic composition of thermophilous Pieniny meadow?

    NASA Astrophysics Data System (ADS)

    Józefowska, Agnieszka; Zaleski, Tomasz; Zarzycki, Jan

    2016-04-01

    The study area was located in the Pieniny National Park in the Carpathian Mountain (Southern Poland). About 30% of Park's area is covered by meadows. The climax stage of this area is forest. Therefore extensive use is indispensable action to keep semi-natural grassland such as termophilous Pieniny meadows, which are characterized by a very high biodiversity. The purpose of this research was to answer the question, how the different way of mowing: traditional scything (H), and mechanical mowing (M) or abandonment of mowing (N) effect on the biological activity of soil. Soil biological activity has been expressed by microbial and soil fauna activity. Microbial activity was described directly by count of microorganisms and indirectly by enzymatic activity (dehydrogenase - DHA) and the microbial biomass carbon content (MBC). Enchytraeidae and Lumbricidae were chosen as representatives of soil fauna. Density and species diversity of this Oligochaeta was determined. Samples were collected twice in June (before mowing) and in September (after mowing). Basic soil properties, such as pH value, organic carbon and nitrogen content, moisture and temperature, were determined. Mean count of vegetative bacteria forms, fungi and Actinobacteria was higher in H than M and N. Amount of bacteria connected with nitrification and denitrification process and Clostridium pasteurianum was the highest in soil where mowing was discontinued 11 years ago. The microbial activity measured indirectly by MBC and DHA indicated that the M had the highest activity. The soil biological activity in second term of sampling had generally higher activity than soil collected in June. That was probably connected with highest organic carbon content in soil resulting from mowing and the end of growing season. Higher earthworm density was in mowing soil (220 and 208 individuals m-2 in H and M respectively) compare to non-mowing one (77 ind. m-2). The density of Enchytraeidae was inversely, the higher density

  10. Does the different mowing regime affect soil biological activity and floristic composition of thermophilous Pieniny meadow?

    NASA Astrophysics Data System (ADS)

    Józefowska, Agnieszka; Zaleski, Tomasz; Zarzycki, Jan

    2016-04-01

    The study area was located in the Pieniny National Park in the Carpathian Mountain (Southern Poland). About 30% of Park's area is covered by meadows. The climax stage of this area is forest. Therefore extensive use is indispensable action to keep semi-natural grassland such as termophilous Pieniny meadows, which are characterized by a very high biodiversity. The purpose of this research was to answer the question, how the different way of mowing: traditional scything (H), and mechanical mowing (M) or abandonment of mowing (N) effect on the biological activity of soil. Soil biological activity has been expressed by microbial and soil fauna activity. Microbial activity was described directly by count of microorganisms and indirectly by enzymatic activity (dehydrogenase - DHA) and the microbial biomass carbon content (MBC). Enchytraeidae and Lumbricidae were chosen as representatives of soil fauna. Density and species diversity of this Oligochaeta was determined. Samples were collected twice in June (before mowing) and in September (after mowing). Basic soil properties, such as pH value, organic carbon and nitrogen content, moisture and temperature, were determined. Mean count of vegetative bacteria forms, fungi and Actinobacteria was higher in H than M and N. Amount of bacteria connected with nitrification and denitrification process and Clostridium pasteurianum was the highest in soil where mowing was discontinued 11 years ago. The microbial activity measured indirectly by MBC and DHA indicated that the M had the highest activity. The soil biological activity in second term of sampling had generally higher activity than soil collected in June. That was probably connected with highest organic carbon content in soil resulting from mowing and the end of growing season. Higher earthworm density was in mowing soil (220 and 208 individuals m‑2 in H and M respectively) compare to non-mowing one (77 ind. m‑2). The density of Enchytraeidae was inversely, the higher

  11. A Model of Beaver Meadow Complex Evolution in the Silvies River Basin, Oregon.

    NASA Astrophysics Data System (ADS)

    Nash, C.; Grant, G.; Campbell, S. D.

    2014-12-01

    There is increasing evidence to suggest that the pervasive incision seen in the American West is due, in part, to the removal of beaver (Castor canadensis) in the first half of the 19th century. New restoration strategies for these systems focus on the reintroduction of beaver and construction of beaver dam analogs. Such dams locally raise streams beds and water tables, reconnect incised channels to their former floodplains, trap sediment, increase hydraulic diversity, and promote riparian vegetation. However, the geomorphic and hydrologic impacts of both the original beaver dams and their analogs are poorly understood. Observations in the Silvies River basin in Oregon, USA - an upland, semi-arid catchment with extremely high historic beaver populations and a presently recovering population, inform a conceptual model for valley floor evolution with beaver dams. The evolution of the beaver dam complex is characterized by eight stages of morphologic adjustment: water impoundment, sediment deposition, pond filling, multi-thread meadow creation, dam breaching, channel incision, channel widening, and floodplain development. Well-constructed beaver dams, given sufficient time and sediment flux, will evolve from a series of ponds to a multi-threaded channel flowing through a wet meadow complex. If a dam in the system fails, due to overtopping, undercutting, lack of maintenance, or abandonment, the upstream channel will concentrate into a single channel and incise, followed over time by widening once critical bank heights are exceeded. From stratigraphic, dendrochronologic, and geomorphic measurements, we are constraining average timescales associated with each stage's duration and transitional period. Measured sedimentation rates behind modern beaver dam analogs on five stream systems permit calculation of sediment flux over recent time periods, and aid in developing regional rates of sediment deposition over a range of drainage areas and gradients. Stratigraphic and

  12. Butterfly Density and Behaviour in Uncut Hay Meadow Strips: Behavioural Ecological Consequences of an Agri-Environmental Scheme

    PubMed Central

    Lebeau, Julie; Wesselingh, Renate A.; Van Dyck, Hans

    2015-01-01

    Sparing zones from mowing has been proposed, and applied, to improve local conditions for survival and reproduction of insects in hay meadows. However, little is known about the efficiency of refuge zones and the consequences for local populations. We studied population densities of butterflies before and after mowing in the refuge zone of 15 meadows in 2009 and 2011. We also studied the behaviour of the meadow brown (Maniola jurtina) comparing nectar use, interactions and flights in the refuge zone before and after mowing. Densities of grassland butterflies in this zone doubled on average after mowing. The density of females of M. jurtina increased on average fourfold, while males showed a more modest increase. In line with the idea of increased scramble competition in the refuge zone after mowing, M. jurtina increased the time spent on nectar feeding, the preferred nectar source was visited more frequently, and females made more use of non-preferred nectar sources. Maniola jurtina did not interact more with conspecifics after mowing, but interactions lasted longer. Flight tracks did not change in linearity, but were faster and shorter after mowing. After mowing, only a part of the local grassland butterflies moved to the uncut refuge zone. The resulting concentration effect alters the time allocated to different activities, nectar use and movements. These aspects have been largely ignored for agri-environmental schemes and grassland management in nature reserves and raise questions about optimal quantities and quality of uncut refuge sites for efficient conservation of grassland arthropods in agricultural landscapes. PMID:26284618

  13. Bacterial diversity of siliciclastic sediments in a Thalassia testudinum meadow and the implications for Lucinisca nassula chemosymbiosis

    NASA Astrophysics Data System (ADS)

    Green-García, Angela M.; Engel, Annette Summers

    2012-10-01

    Despite the ecological and economic importance of Thalassia testudinum (turtle grass) meadows along the Caribbean and Gulf of Mexico coasts, and recognition that microbial activities are critical to plant growth and health, the bacterial diversity of these habitats has been poorly studied. Based on comparative analyses of 16S rRNA gene sequences from sediments in a T. testudinum meadow, 25 major taxonomic groups (excluding candidate divisions) were retrieved, including Alpha- Delta-, and Gamma-proteobacteria, Chloroflexi, Bacteroidetes, Acidobacteria, Spirochaetes, and Firmicutes. The distribution of bacterial groups was linked to a strongly hypoxic and sulfidic redox gradient. The diversity is potentially novel because phylogenetic affinities of sediment sequences compared to contextually annotated environmental clones from different habitats or to cultured representatives indicated approximately 41% were more closely related to each other than to sequences retrieved from these other habitats. Of all the relationships, very few (2.4%) were to cultured organisms, but 27% were to environmental clones retrieved from shallow marine shelf and coastal sediments or from mangroves, estuarine, or wetland sediments. Rare sequences were closely related to endosymbiont groups of Lucinisca nassula (Lucinidea: Bivalvia) hosts collected from the same meadow, which may indicate that the sediment is a potential reservoir for free-living symbionts. This study provides insight into the ecological and evolutionary relationships of the Thalassia-lucinid-bacteria system in tropical to sub-tropical regions.

  14. Responses of plant community composition and biomass production to warming and nitrogen deposition in a temperate meadow ecosystem.

    PubMed

    Zhang, Tao; Guo, Rui; Gao, Song; Guo, Jixun; Sun, Wei

    2015-01-01

    Climate change has profound influences on plant community composition and ecosystem functions. However, its effects on plant community composition and biomass production are not well understood. A four-year field experiment was conducted to examine the effects of warming, nitrogen (N) addition, and their interactions on plant community composition and biomass production in a temperate meadow ecosystem in northeast China. Experimental warming had no significant effect on plant species richness, evenness, and diversity, while N addition highly reduced the species richness and diversity. Warming tended to reduce the importance value of graminoid species but increased the value of forbs, while N addition had the opposite effect. Warming tended to increase the belowground biomass, but had an opposite tendency to decrease the aboveground biomass. The influences of warming on aboveground production were dependent upon precipitation. Experimental warming had little effect on aboveground biomass in the years with higher precipitation, but significantly suppressed aboveground biomass in dry years. Our results suggest that warming had indirect effects on plant production via its effect on the water availability. Nitrogen addition significantly increased above- and below-ground production, suggesting that N is one of the most important limiting factors determining plant productivity in the studied meadow steppe. Significant interactive effects of warming plus N addition on belowground biomass were also detected. Our observations revealed that environmental changes (warming and N deposition) play significant roles in regulating plant community composition and biomass production in temperate meadow steppe ecosystem in northeast China.

  15. Invasion of dwarf bamboo into alpine snow-meadows in northern Japan: pattern of expansion and impact on species diversity

    PubMed Central

    Kudo, Gaku; Amagai, Yukihiro; Hoshino, Buho; Kaneko, Masami

    2011-01-01

    Recently, a dwarf bamboo species,Sasa kurilensis; Poaceae, has invaded into alpine snow-meadows in the wilderness area of the Taisetsu Mountains, northern Japan. This dwarf bamboo species has a wide distribution range from lowland to alpine sites of snowy regions. Because of the formation of dense evergreen culms and an extensive rhizome system, other plants are excluded following invasion by this dwarf bamboo, resulting in low species diversity. Dwarf bamboo originally inhabited the leeward slopes of alpine dwarf pine (Pinus pumila) clumps in alpine regions. During the last 32 years, however, dwarf bamboo has expanded its distribution area by up to 47% toward snow-meadows, especially on southeastern facing slopes. This rapid change may be related to the decrease in soil moisture and expansion of the annual growing period caused by the recent acceleration of snowmelt time. A multiyear census revealed that the density of bamboo culms increased 30–150% during 2 years, and the annual expansion of bamboo rhizomes was 39 cm on average. In addition to the expansion of bamboo clumps by vegetative growth, the possibility of migration by seed dispersal was also suggested by a genet analysis. With the increase in culm density, the species richness of snow-meadow vegetation decreased to less than one-quarter of the original level due to intense shading by dwarf bamboo. The rapid vegetation change in these almost pristine alpine environments isolated from the human activity implies that global climate change already influences the alpine ecosystem. PMID:22393485

  16. Short-term effect of nitrogen addition on nitric oxide emissions from an alpine meadow in the Tibetan Plateau.

    PubMed

    Gao, Yongheng; Ma, Xingxing; Cooper, David J

    2016-06-01

    Little information is available on nitric oxide (NO) fluxes from alpine ecosystems. We measured NO fluxes in control and nitrogen (N) addition (NH4NO3, 6 g N m(-2) year(-1)) plots from early June through October 2013 in an alpine meadow on the Tibetan Plateau, China. During the sample period, NO fluxes varied from -0.71 to 3.12 ug m(-2) h(-1) and -0.46 to 7.54 ug m(-2) h(-1) for control and N treatment plots. The mean NO emission in N addition plots (1.68 ug m(-2) h(-1)) was 2.15 times higher than the control plots (0.78 ug m(-2) h(-1)), indicating that alpine meadows may be a source of atmospheric NO, and N additions stimulated NO flux. A positive correlation was found between NO flux and soil temperature, water-filled pore space (WFPS), nitrate (NO3 (-)-N) content but no correlation with soil ammonium (NH4 (+)-N). These results suggest that denitrification is a principal process producing NO flux from alpine meadows.

  17. Responses of Plant Community Composition and Biomass Production to Warming and Nitrogen Deposition in a Temperate Meadow Ecosystem

    PubMed Central

    Gao, Song; Guo, Jixun; Sun, Wei

    2015-01-01

    Climate change has profound influences on plant community composition and ecosystem functions. However, its effects on plant community composition and biomass production are not well understood. A four-year field experiment was conducted to examine the effects of warming, nitrogen (N) addition, and their interactions on plant community composition and biomass production in a temperate meadow ecosystem in northeast China. Experimental warming had no significant effect on plant species richness, evenness, and diversity, while N addition highly reduced the species richness and diversity. Warming tended to reduce the importance value of graminoid species but increased the value of forbs, while N addition had the opposite effect. Warming tended to increase the belowground biomass, but had an opposite tendency to decrease the aboveground biomass. The influences of warming on aboveground production were dependent upon precipitation. Experimental warming had little effect on aboveground biomass in the years with higher precipitation, but significantly suppressed aboveground biomass in dry years. Our results suggest that warming had indirect effects on plant production via its effect on the water availability. Nitrogen addition significantly increased above- and below-ground production, suggesting that N is one of the most important limiting factors determining plant productivity in the studied meadow steppe. Significant interactive effects of warming plus N addition on belowground biomass were also detected. Our observations revealed that environmental changes (warming and N deposition) play significant roles in regulating plant community composition and biomass production in temperate meadow steppe ecosystem in northeast China. PMID:25874975

  18. Invasion of dwarf bamboo into alpine snow-meadows in northern Japan: pattern of expansion and impact on species diversity.

    PubMed

    Kudo, Gaku; Amagai, Yukihiro; Hoshino, Buho; Kaneko, Masami

    2011-09-01

    Recently, a dwarf bamboo species,Sasa kurilensis; Poaceae, has invaded into alpine snow-meadows in the wilderness area of the Taisetsu Mountains, northern Japan. This dwarf bamboo species has a wide distribution range from lowland to alpine sites of snowy regions. Because of the formation of dense evergreen culms and an extensive rhizome system, other plants are excluded following invasion by this dwarf bamboo, resulting in low species diversity. Dwarf bamboo originally inhabited the leeward slopes of alpine dwarf pine (Pinus pumila) clumps in alpine regions. During the last 32 years, however, dwarf bamboo has expanded its distribution area by up to 47% toward snow-meadows, especially on southeastern facing slopes. This rapid change may be related to the decrease in soil moisture and expansion of the annual growing period caused by the recent acceleration of snowmelt time. A multiyear census revealed that the density of bamboo culms increased 30-150% during 2 years, and the annual expansion of bamboo rhizomes was 39 cm on average. In addition to the expansion of bamboo clumps by vegetative growth, the possibility of migration by seed dispersal was also suggested by a genet analysis. With the increase in culm density, the species richness of snow-meadow vegetation decreased to less than one-quarter of the original level due to intense shading by dwarf bamboo. The rapid vegetation change in these almost pristine alpine environments isolated from the human activity implies that global climate change already influences the alpine ecosystem.

  19. Temperature sensitivity of soil carbon dioxide and nitrous oxide emissions in mountain forest and meadow ecosystems in China

    NASA Astrophysics Data System (ADS)

    Zhang, Junjun; Peng, Changhui; Zhu, Qiuan; Xue, Wei; Shen, Yan; Yang, Yanzheng; Shi, Guohua; Shi, Shengwei; Wang, Meng

    2016-10-01

    An incubation experiment was conducted at three temperature levels (8, 18 and 28 °C) to quantify the response of soil CO2 and N2O emissions to temperature in three ecosystems (pine forest, oak forest, and meadow) located in the Qinling Mountains of China, which are considered to be susceptible to disturbance and climate changes, especially global warming. The soil CO2 emission rates increased with temperature and decreased with soil depth; they were the highest in the oak forest (broadleaf forest) and were lower in the pine forest (coniferous forest) and the meadow ecosystem. However, there was no significant difference in the soil N2O emission rates among the three ecosystems. The temperature sensitivity of CO2 and N2O was higher in the forest than in the meadow ecosystem. The Q10 values (temperature sensitivity coefficient) for CO2 and N2O were 1.07-2.25 and 0.82-1.22, respectively, for the three ecosystems. There was also evidence that the CO2 and N2O emission rates were positively correlated. The soil characteristics exhibited different effects on CO2 and N2O emissions among different ecosystems at the three temperature levels. Moreover, the soil dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA) and nitrate (NO3-) were important factors for CO2 emissions, whereas the soil ammonium (NH4+) and pH were the major controllers of N2O emissions. Unexpectedly, our results indicated that CO2 emissions are more sensitive to increasing temperature than N2O, noting the different feedback of CO2 and N2O emissions to global warming in this region. The different responses of greenhouse gas emissions in different forest types and a meadow ecosystem suggest that it is critical to conduct a comprehensive investigation of the complex mountain forest and meadow ecosystem in the transitional climate zone under global warming. Our research results provide new insight and advanced understanding of the variations in major greenhouse gas emissions (CO2 and N2O

  20. Long-term carbon storage and its recent loss in an estuarine Posidonia australis meadow (Albany, Western Australia)

    NASA Astrophysics Data System (ADS)

    Rozaimi, Mohammad; Lavery, Paul S.; Serrano, Oscar; Kyrwood, Danielle

    2016-03-01

    Oyster Harbour, on the south coast of Western Australia, supports 3.6-3.9 km2 of seagrass meadows, following the loss of approximately 2.8-3.1 km2 in the 1980s. This small area of prevailing meadows hold significant carbon stores accumulated over the past 3000 years. In this study, we sampled three sediment cores from a Posidonia australis meadow and analysed organic matter (OM), organic carbon (OC) and inorganic carbon (IC) contents in bulk sediments, and δ13C signatures of OM. The OM and OC contents (mean ± SE) in the cores were 9.07 ± 0.36% and 2.24 ± 0.05%, respectively. The mean IC content was 3.16 ± 0.17%. δ13C signatures of the sedimentary OM ranged from -10.01‰ to -13.28‰. Using a Bayesian isotopic mixing model, it is estimated that 57-67% of the OM in the seagrass sediments was derived from P. australis detrital matter. The total carbon (TC) stores in 150 cm-thick seagrass sediments averaged 27.92 kg TC m-2 (10.79 kg OC m-2 and 17.13 kg IC m-2). Based on radiocarbon dating, the mean sediment accumulation rate was 0.0494 cm yr-1, which led to a long-term TC accumulation rate of 8.92 g TC m-2 yr-1 (3.45 g OC m-2 yr-1 and 5.47 g IC m-2 yr-1). Based on historical seagrass cover (3.6-6.7 km2 during the 1960s to 1980s), the estimated TC stores in 150 cm-thick seagrass sediments at Oyster Harbour would have been 101-187 Gg TC. The eutrophication-driven loss of seagrasses during the 1980s resulted in the absence of OC accumulation capacity amounting to 280-310 Mg OC (over 29 years). The loss of seagrass area could also have resulted in the release of 37-41 Gg CO2, assuming that all of the OC in shallow sediment is remineralised after meadow disturbance. These results exemplify the importance of seagrasses meadows as important carbon sinks and the potential for losses of carbon stores due to ecosystem degradation.

  1. Highly diverse molluscan assemblages of Posidonia oceanica meadows in northwestern Alboran Sea (W Mediterranean): Seasonal dynamics and environmental drivers

    NASA Astrophysics Data System (ADS)

    Urra, Javier; Mateo Ramírez, Ángel; Marina, Pablo; Salas, Carmen; Gofas, Serge; Rueda, José L.

    2013-01-01

    The seasonal dynamics of the molluscan fauna associated with the westernmost populations of the Mediterranean seagrass Posidonia oceanica, has been studied throughout an annual cycle in the northwestern coasts of the Alboran Sea. Samples were collected seasonally (5 replicated per season) using a non-destructive sampling technique (airlift sampler) on quadrats of 50 × 50 cm at 2 sites located 7 km apart. Several environmental variables from the water column (temperature, chlorophyll a), the sediment (percentage of organic matter) and the seagrass meadows (shoot density, leaf height and width, number of leaves per shoot) were also measured in order to elucidate their relationships with the dynamics of the molluscan assemblages. In these meadows, a total of 17,416 individuals of molluscs were collected, belonging to 71 families and 171 species, being Rissoidae, Pyramidellidae and Trochidae the best-represented families, and Mytilidae, Nassaridae and Trochidae the dominant ones in terms of abundance. The assemblages were dominated by micro-algal grazers, filter feeders and ectoparasites (including those feeding on sessile preys). The species richness and the abundance displayed significant maximum values in summer, whereas evenness and diversity displayed maximum values in spring, being significant for the evenness. Both abundance and species richness values were positively correlated to seawater temperature and percentage organic matter, only for the latter, and negatively to leaf width. Significant seasonal groupings were obtained with multivariate analyses (MDS, Cluster, ANOSIM) using qualitative and quantitative data that could be mainly related to biological aspects (i.e. recruitment) of single species. The molluscan assemblages are influenced by the biogeographical location of the area (Alboran Sea), reflected in the absence or scarcity of most Mediterranean species strictly associated with P. oceanica (e.g. Tricolia speciosa, Rissoa ventricosa) and by the

  2. Complex responses of spring vegetation growth to climate in a moisture-limited alpine meadow

    NASA Astrophysics Data System (ADS)

    Ganjurjav, Hasbagan; Gao, Qingzhu; Schwartz, Mark W.; Zhu, Wenquan; Liang, Yan; Li, Yue; Wan, Yunfan; Cao, Xujuan; Williamson, Matthew A.; Jiangcun, Wangzha; Guo, Hongbao; Lin, Erda

    2016-03-01

    Since 2000, the phenology has advanced in some years and at some locations on the Qinghai-Tibetan Plateau, whereas it has been delayed in others. To understand the variations in spring vegetation growth in response to climate, we conducted both regional and experimental studies on the central Qinghai-Tibetan Plateau. We used the normalized difference vegetation index to identify correlations between climate and phenological greening, and found that greening correlated negatively with winter-spring time precipitation, but not with temperature. We used open top chambers to induce warming in an alpine meadow ecosystem from 2012 to 2014. Our results showed that in the early growing season, plant growth (represented by the net ecosystem CO2 exchange, NEE) was lower in the warmed plots than in the control plots. Late-season plant growth increased with warming relative to that under control conditions. These data suggest that the response of plant growth to warming is complex and non-intuitive in this system. Our results are consistent with the hypothesis that moisture limitation increases in early spring as temperature increases. The effects of moisture limitation on plant growth with increasing temperatures will have important ramifications for grazers in this system.

  3. Complex responses of spring vegetation growth to climate in a moisture-limited alpine meadow

    PubMed Central

    Ganjurjav, Hasbagan; Gao, Qingzhu; Schwartz, Mark W.; Zhu, Wenquan; Liang, Yan; Li, Yue; Wan, Yunfan; Cao, Xujuan; Williamson, Matthew A.; Jiangcun, Wangzha; Guo, Hongbao; Lin, Erda

    2016-01-01

    Since 2000, the phenology has advanced in some years and at some locations on the Qinghai-Tibetan Plateau, whereas it has been delayed in others. To understand the variations in spring vegetation growth in response to climate, we conducted both regional and experimental studies on the central Qinghai-Tibetan Plateau. We used the normalized difference vegetation index to identify correlations between climate and phenological greening, and found that greening correlated negatively with winter-spring time precipitation, but not with temperature. We used open top chambers to induce warming in an alpine meadow ecosystem from 2012 to 2014. Our results showed that in the early growing season, plant growth (represented by the net ecosystem CO2 exchange, NEE) was lower in the warmed plots than in the control plots. Late-season plant growth increased with warming relative to that under control conditions. These data suggest that the response of plant growth to warming is complex and non-intuitive in this system. Our results are consistent with the hypothesis that moisture limitation increases in early spring as temperature increases. The effects of moisture limitation on plant growth with increasing temperatures will have important ramifications for grazers in this system. PMID:26983697

  4. Impacts of different climate change regimes and extreme climatic events on an alpine meadow community

    PubMed Central

    Alatalo, Juha M.; Jägerbrand, Annika K.; Molau, Ulf

    2016-01-01

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity PMID:26888225

  5. Effects of cattle grazing on small mammal communities in the Hulunber meadow steppe.

    PubMed

    Cao, Chan; Shuai, Ling-Ying; Xin, Xiao-Ping; Liu, Zhi-Tao; Song, Yan-Ling; Zeng, Zhi-Gao

    2016-01-01

    Small mammals play important roles in many ecosystems, and understanding their response to disturbances such as cattle grazing is fundamental for developing sustainable land use strategies. However, how small mammals respond to cattle grazing remains controversial. A potential cause is that most of previous studies adopt rather simple experimental designs based solely on the presence/absence of grazing, and are thus unable to detect any complex relationships between diversity and grazing intensity. In this study, we conducted manipulated experiments in the Hulunber meadow steppe to survey small mammal community structures under four levels of grazing intensities. We found dramatic changes in species composition in native small mammal communities when grazing intensity reached intermediate levels (0.46 animal unit/ha). As grazing intensity increased, Spermophilus dauricus gradually became the single dominant species. Species richness and diversity of small mammals in ungrazed and lightly grazed (0.23 animal unit/ha) area were much higher than in intermediately and heavily grazed area. We did not detect a humped relationship between small mammal diversity and disturbance levels predicted by the intermediate disturbance hypothesis (IDH). Our study highlighted the necessity of conducting manipulated experiments under multiple grazing intensities.

  6. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain).

    PubMed

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988-1990 and 2009-2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:25878552

  7. Responses of community-level plant-insect interactions to climate warming in a meadow steppe

    PubMed Central

    Zhu, Hui; Zou, Xuehui; Wang, Deli; Wan, Shiqiang; Wang, Ling; Guo, Jixun

    2015-01-01

    Climate warming may disrupt trophic interactions, consequently influencing ecosystem functioning. Most studies have concentrated on the temperature-effects on plant-insect interactions at individual and population levels, with a particular emphasis on changes in phenology and distribution. Nevertheless, the available evidence from the community level is limited. A 3-year field manipulative experiment was performed to test potential responses of plant and insect communities, and plant-insect interactions, to elevated temperature in a meadow steppe. Warming increased the biomass of plant community and forbs, and decreased grass biomass, indicating a shift from grass-dominant to grass-forb mixed plant community. Reduced abundance of the insect community under warming, particularly the herbivorous insects, was attributed to lower abundance of Euchorthippus unicolor and a Cicadellidae species resulting from lower food availability and higher defensive herbivory. Lower herbivore abundance caused lower predator species richness because of reduced prey resources and contributed to an overall decrease in insect species richness. Interestingly, warming enhanced the positive relationship between insect and plant species richness, implying that the strength of the plant-insect interactions was altered by warming. Our results suggest that alterations to plant-insect interactions at a community level under climate warming in grasslands may be more important and complex than previously thought. PMID:26686758

  8. Heavy metal sensitivity and bioconcentration in oribatid mites (Acari, Oribatida) Gradient study in meadow ecosystems.

    PubMed

    Skubała, Piotr; Zaleski, Tomasz

    2012-01-01

    In this study we aimed to identify different reactions of oribatid species to heavy metal pollution and to measure concentrations of cadmium, zinc and copper in oribatid species sampled along a gradient. Oribatid mites were sampled seasonally during two years in five meadows located at different distances from the zinc smelter in the Olkusz District, southern Poland. Oribatids were shown to withstand critical metal concentration and established comparatively abundant and diverse communities. The highest abundance and species richness of oribatids were recorded in soils with moderate concentrations of heavy metals. Four different responses of oribatid species to heavy metal pollution were recognized. Heavy metals (Zn, Pb, Cd, Ni) and various physical (bulk density, field capacity, total porosity) and chemical (K(av), P(av), N, C, pH) factors were recognized as the structuring forces that influence the distribution of oribatid species. Analysis by atomic absorption spectrophotometry revealed large differences in metal body burdens among species. None of the species can be categorized as accumulators or non-accumulators of the heavy metals - the pattern depends on the metal. The process of bioconcentration of the toxic metal (regulated) and essential elements (accumulated) was generally different in the five oribatid species studied. PMID:22134027

  9. The ecology of the seagrass meadows of the west coast of Florida: A community profile

    SciTech Connect

    Zieman, J.C.; Zieman, R.T. . Dept. of Environmental Sciences)

    1989-09-01

    This report summarizes information on the ecology of seagrass meadows on the west coast of Florida, from south of Tampa Bay to Pensacola. This area contains more than 3500 ha of seagrass beds, dominated by three species, Thalasia testudinum (turtle grass), Syringodium filiforme (manatee grass), and Halodule wrightii (shoal grass). Beds occur both on the shallow, zero-energy Continental Shelf and in inshore bays and estuaries. Species ecology, distribution, biomass, and productivity of these dominant seagrass species are discussed. Seagrass beds support a very diverse and abundant algal flora and fauna, and these organisms, and seagrass detritus form the base of a productive food chain. Seagrass beds are important nursery areas providing both cover and food, for a number of commercial and sports fishery species. Along the west Florida coast, estuarine grass beds are noticeably more stressed and impacted by human activities than the more pristine nearshore beds. Urban development and dredging and filling are the major threates to seagrass beds in this region. 500 refs., 28 figs., 14 tabs.

  10. Day length and estradiol affect same-sex affiliative behavior in the female meadow vole

    PubMed Central

    Beery, Annaliese K.; Loo, Theresa J.; Zucker, Irving

    2008-01-01

    Non-sexual social bonding between adult mammals remains poorly understood, despite its importance in many species. Female meadow voles are territorial and nest alone in long summer day lengths when circulating estradiol concentrations are high, but cohabit in groups in short winter photoperiods when estradiol secretion is low. The influence of day length and estradiol on same-sex huddling behavior was assessed in adult female pairs housed together in long day lengths (LDs) or short day lengths (SDs) from weaning. The behavior of intact, ovariectomized, and estradiol-treated ovariectomized females from each photoperiod was assessed during 3 hour partner preference tests. Intact SD voles, unlike intact LD voles, spent the majority of the test in proximity to their cage mates. Estradiol treatment of SD voles significantly reduced time spent huddling with the partner. Neither ovariectomy nor estradiol treatment significantly affected the amount of time LD females spent in contact with their partners. Low estradiol availability is therefore a necessary but not sufficient condition for maintenance of high levels of huddling. These results establish that ovarian hormones interact with photoperiod to affect same-sex social behavior. PMID:18387611

  11. An experimental approach to assessing the effects of mining subsidence on a flood meadow community

    SciTech Connect

    Benyon, P.R.; Humphries, R.N.; Gregson, K.; Marshall, S.; Peace, S.W.

    1998-12-31

    The Lower Derwent Valley (LDV) is a candidate Special Area of Conservation (SAC) under the provisions of the UK 1994 Conservation Regulations for its internationally important Alopecurus pratense-Sanguisorba officinalis flood meadow vegetation. Mining from RJB`s Selby Complex (UK`s largest mine) has taken place around and under the LDV since the 1980s. Under the provisions of the Regulations the potential effects of mining subsidence have been recently reviewed. From field data and models it has been predicted that the resulting small amount of subsidence is unlikely to have a deleterious effect on the composition and extent of the key community. While the proposed long-term monitoring will verify the prediction, it will be some years before the results will be available. In order to identify incipient changes in grassland community and to implement any necessary mitigation measures before significant changes occur, a field experiment was set up in late 1996 to assess the effects of increased wetness and inundation which might be induced by subsidence. This involved the transplantation of turves from the different grassland communities within and along a previously defined gradient of relative wetness and inundation. The response of the communities to the different conditions is being monitored. The background studies and the results of the transplantation so far will be presented.

  12. Invertebrate response to nutrient-driven epiphytic load increase in Posidonia oceanica meadows

    NASA Astrophysics Data System (ADS)

    Castejón-Silvo, Inés; Domínguez, Marta; Terrados, Jorge; Tomas, Fiona; Morales-Nin, Beatriz

    2012-10-01

    Nutrient increases in coastal systems are becoming a world-wide concern since they promote strong structural and functional changes in shallow ecosystems. Increased nutrient availability in the water column may strongly enhance the leaf epiphytic communities of key habitat-forming species such as seagrasses through a bottom-up mechanism, competing for light and nutrients with the leaves. Epiphytes support an abundant and diverse community of resident invertebrates which fuel higher trophic levels in Posidonia oceanica food webs. We evaluated the response of seagrass, epiphytes and the invertebrate community to an experimental increase of water column nutrient availability. Nutrient increase was followed by a rise of epiphyte biomass. The increase in epiphytic biomass promoted invertebrate abundance, but appeared to have negative effects on P. oceanica shoot size. On the other hand, the increase in invertebrate abundance did not seem to control epiphytic biomass, which was not reversed to pre-nutrient enrichment levels. This work suggests that the abundance of invertebrate populations is limited by epiphyte biomass, through food or habitat provision, in P. oceanica systems and points to nutrients as the main driver of epiphyte biomass during summer. The results illustrate the control mechanisms at community level in P. oceanica meadows and the possible responses of a threatened ecosystem to human impact such as eutrophication.

  13. Effects of cattle grazing on small mammal communities in the Hulunber meadow steppe

    PubMed Central

    Xin, Xiao-Ping; Liu, Zhi-Tao; Song, Yan-Ling

    2016-01-01

    Small mammals play important roles in many ecosystems, and understanding their response to disturbances such as cattle grazing is fundamental for developing sustainable land use strategies. However, how small mammals respond to cattle grazing remains controversial. A potential cause is that most of previous studies adopt rather simple experimental designs based solely on the presence/absence of grazing, and are thus unable to detect any complex relationships between diversity and grazing intensity. In this study, we conducted manipulated experiments in the Hulunber meadow steppe to survey small mammal community structures under four levels of grazing intensities. We found dramatic changes in species composition in native small mammal communities when grazing intensity reached intermediate levels (0.46 animal unit/ha). As grazing intensity increased, Spermophilus dauricus gradually became the single dominant species. Species richness and diversity of small mammals in ungrazed and lightly grazed (0.23 animal unit/ha) area were much higher than in intermediately and heavily grazed area. We did not detect a humped relationship between small mammal diversity and disturbance levels predicted by the intermediate disturbance hypothesis (IDH). Our study highlighted the necessity of conducting manipulated experiments under multiple grazing intensities. PMID:27635323

  14. Phylogenetic conservatism and climate factors shape flowering phenology in alpine meadows.

    PubMed

    Li, Lanping; Li, Zhikuo; Cadotte, Marc W; Jia, Peng; Chen, Guanguang; Jin, Lanna S; Du, Guozhen

    2016-10-01

    The study of phylogenetic conservatism in alpine plant phenology is critical for predicting climate change impacts; currently we have a poor understanding of how phylogeny and climate factors interactively influence plant phenology. Therefore, we explored the influence of phylogeny and climate factors on flowering phenology in alpine meadows. For two different types of alpine plant communities, we recorded phenological data, including flowering peak, first flower budding, first flowering, first fruiting and the flowering end for 62 species over the course of 5 years (2008-2012). From sequences in two plastid regions, we constructed phylogenetic trees. We used Blomberg's K and Pagel's lambda to assess the phylogenetic signal in phenological traits and species' phenological responses to climate factors. We found a significant phylogenetic signal in the date of all reproductive phenological events and in species' phenological responses to weekly day length and temperature. The number of species in flower was strongly associated with the weekly day lengths and followed by the weekly temperature prior to phenological activity. Based on phylogenetic eigenvector regression (PVR) analysis, we found a highly shared influence of phylogeny and climate factors on alpine species flowering phenology. Our results suggest the phylogenetic conservatism in both flowering and fruiting phenology may depend on the similarity of responses to external environmental cues among close relatives. PMID:27351544

  15. Using biogeographical history to inform conservation: the case of Preble's meadow jumping mouse.

    PubMed

    Malaney, Jason L; Cook, Joseph A

    2013-12-01

    The last Pleistocene deglaciation shaped temperate and boreal communities in North America. Rapid northward expansion into high latitudes created distinctive spatial genetic patterns within species that include closely related groups of populations that are now widely spread across latitudes, while longitudinally adjacent populations, especially those near the southern periphery, often are distinctive due to long-term disjunction. Across a spatial expanse that includes both recently colonized and long-occupied regions, we analysed molecular variation in zapodid rodents to explore how past climate shifts influenced diversification in this group. By combining molecular analyses with species distribution modelling and tests of ecological interchangeability, we show that the lineage including the Preble's meadow jumping mouse (Zapus hudsonius preblei), a US federally listed taxon of conservation concern, is not restricted to the southern Rocky Mountains. Rather, populations along the Front Range are part of a single lineage that is ecologically indistinct and extends to the far north. Of the 21 lineages identified, this Northern lineage has the largest geographical range and low measures of intralineage genetic differentiation, consistent with recent northward expansion. Comprehensive sampling combined with coalescent-based analyses and niche modelling leads to a radically different view of geographical structure within jumping mice and indicates the need to re-evaluate their taxonomy and management. This analysis highlights a premise in conservation biology that biogeographical history should play a central role in establishing conservation priorities.

  16. Genetic structure of eelgrass Zostera marina meadows in an embayment with restricted water flow

    USGS Publications Warehouse

    Munoz-Salazar, R.; Talbot, S.L.; Sage, G.K.; Ward, D.H.; Cabello-Pasini, Alejandro

    2006-01-01

    Genetic structure of the seagrass Zostera marina in a coastal lagoon with restricted water flow, and with heterogeneous water residence times and oceanographic characteristics, was assessed using 8 polymorphic microsatellite loci. Analyses of genetic differentiation (??) and Bayesian clustering suggested that the Z. marina population in San Quintin Bay (SQB) is genetically substructured, with at least 4 genetically different groups: (1) West Head, (2) Mouth, (3) East Arm, and (4) East Head. The greatest ?? value was observed between the most distant sites (?? = 0.095). The lowest values were found among sites closest to the mouth of the coastal lagoon (?? = 0.000 to 0.009). The maximum likelihood approach showed that the sites at the mouth have a mixed pattern of gene flow without a unidirectional pattern. In contrast, there was a clear pattern of asymmetrical gene flow from the mouth towards the West Head. These results suggested that the restriction of water flow at the heads, current pattern, and the distance between sites can reduce genetic flow and promote genetic differences within Z. marina meadows in small water embayments such as SQB. Though the population is genetically substructured and a 14 % decline in cover has been detected, this study did not show evidence of a recent genetic bottleneck. In contrast, mouth sites have experienced a recent expansion in their population size, and also perhaps a recent influx of rare alleles from genetically distinct immigrants. ?? Inter-Research 2006.

  17. Phylogenetic conservatism and climate factors shape flowering phenology in alpine meadows.

    PubMed

    Li, Lanping; Li, Zhikuo; Cadotte, Marc W; Jia, Peng; Chen, Guanguang; Jin, Lanna S; Du, Guozhen

    2016-10-01

    The study of phylogenetic conservatism in alpine plant phenology is critical for predicting climate change impacts; currently we have a poor understanding of how phylogeny and climate factors interactively influence plant phenology. Therefore, we explored the influence of phylogeny and climate factors on flowering phenology in alpine meadows. For two different types of alpine plant communities, we recorded phenological data, including flowering peak, first flower budding, first flowering, first fruiting and the flowering end for 62 species over the course of 5 years (2008-2012). From sequences in two plastid regions, we constructed phylogenetic trees. We used Blomberg's K and Pagel's lambda to assess the phylogenetic signal in phenological traits and species' phenological responses to climate factors. We found a significant phylogenetic signal in the date of all reproductive phenological events and in species' phenological responses to weekly day length and temperature. The number of species in flower was strongly associated with the weekly day lengths and followed by the weekly temperature prior to phenological activity. Based on phylogenetic eigenvector regression (PVR) analysis, we found a highly shared influence of phylogeny and climate factors on alpine species flowering phenology. Our results suggest the phylogenetic conservatism in both flowering and fruiting phenology may depend on the similarity of responses to external environmental cues among close relatives.

  18. Streptomyces erringtonii sp. nov. and Streptomyces kaempferi sp. nov., isolated from a hay meadow soil.

    PubMed

    Santhanam, Rakesh; Rong, Xiaoying; Huang, Ying; Goodfellow, Michael

    2013-01-01

    Two filamentous actinomycetes isolated from a hay meadow soil were provisionally assigned to the genus Streptomyces based on morphological features. The isolates were found to have chemical and morphological properties typical of the genus Streptomyces and formed distinct phyletic lines in the 16S rRNA gene tree. Isolate I36(T) was most closely related to Streptomyces glauciniger NBRC 100913(T) and isolate I37(T) to Streptomyces mirabilis NBRC 13450(T). Low DNA:DNA relatedness values were recorded between each of the isolates and their closest phylogenetic neighbour. The isolates were also distinguished from their nearest phylogenetic neighbour, and from one another, using a combination of phenotypic properties. These data indicate that the isolates should be recognised as new species in the genus Streptomyces. The names proposed for these new taxa are Streptomyces erringtonii sp. nov. and Streptomyces kaempferi sp. nov. with isolate I36(T) (=CGMCC 4.7016(T) = KACC 15424(T)) and isolate I37(T) (=CGMCC 4.7020(T) = KACC 15428(T)) as the respective type strains.

  19. [Effect of grazing on the temperature sensitivity of soil respiration in Hulunber meadow steppe].

    PubMed

    Wang, Xu; Yan, Rui-Rui; Deng, Yu; Yan, Yu-Chun; Xin, Xiao-Ping

    2014-05-01

    Grazing is one of the major human activities which lead to disturbance on grassland ecosystem. Quantifying the effect of grazing on the temperature sensitivity of soil respiration ( Q10 ) is essential for accurate assessment of carbon budget in grassland ecosystem. This study was conducted on the grazing gradients experiment platform in Hulunber meadow steppe. Soil respiration was measured by a dynamic closed chamber method (equipped with Li 6400-09, Lincoln, NE, USA) during the growing season in 2011. The results showed that soil respiration had significant seasonal variation and the maximum occurred in July, which was mainly dominated by temperature. The order of average soil respiration during the period from May to September in different treatments was G1 > GO > G2 > G3 > G4 > G5. Comparing with non-grazing treatment, Q10 under heavy grazing conditions (0. 92 Au hm-2) was reduced by about 10% , and was increased a little under light grazing conditions (0. 23 Au hm-2). There was a significant negative correlation between Q15 and grazing intensities (r = 0. 944, P <0. 05) . Grazing could decrease the temperature sensitivity of soil respiration to different degrees. The Q10 under different grazing gradients had positive linear regression relationships with aboveground biomass, belowground biomass, soil organic carbon and soil moisture. They could explain 71.0%-85.2% variations of Q10. It was suggested that the variation of Q10 was mainly determined by the change of biotic and environmental factors due to grazing.

  20. Nitrogen Critical Loads for an Alpine Meadow Ecosystem on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zong, Ning; Shi, Peili; Song, Minghua; Zhang, Xianzhou; Jiang, Jing; Chai, Xi

    2016-03-01

    Increasing atmospheric nitrogen (N) deposition has the potential to alter plant diversity and thus the function and stability of terrestrial ecosystems. N-limited alpine ecosystems are expected to be particularly susceptible to increasing N deposition. However, little is known about the critical loads and saturation thresholds of ecosystem responses to increasing N deposition on the Tibetan Plateau, despite its importance to ecosystem management. To evaluate the N critical loads and N saturation thresholds in an alpine ecosystem, in 2010, we treated an alpine meadow with five levels of N addition (0, 10, 20, 40, and 80 kg N ha-1 year-1) and characterized plant and soil responses. The results showed that plant species richness and diversity index did not statistically vary with N addition treatments, but they both changed with years. N addition affected plant cover and aboveground productivity, especially for grasses, and soil chemical features. The N critical loads and saturation thresholds, in terms of plant cover and biomass change at the community level, were 8.8-12.7 and 50 kg N ha-1 year-1 (including the ambient N deposition rate), respectively. However, pronounced changes in soil inorganic N and net N mineralization occurred under the 20 and 40 kg N ha-1 year-1 treatments. Our results indicate that plant community cover and biomass are more sensitive than soil to increasing N inputs. The plant community composition in alpine ecosystems on the Qinghai-Tibetan Plateau may change under increasing N deposition in the future.

  1. Effects of cattle grazing on small mammal communities in the Hulunber meadow steppe.

    PubMed

    Cao, Chan; Shuai, Ling-Ying; Xin, Xiao-Ping; Liu, Zhi-Tao; Song, Yan-Ling; Zeng, Zhi-Gao

    2016-01-01

    Small mammals play important roles in many ecosystems, and understanding their response to disturbances such as cattle grazing is fundamental for developing sustainable land use strategies. However, how small mammals respond to cattle grazing remains controversial. A potential cause is that most of previous studies adopt rather simple experimental designs based solely on the presence/absence of grazing, and are thus unable to detect any complex relationships between diversity and grazing intensity. In this study, we conducted manipulated experiments in the Hulunber meadow steppe to survey small mammal community structures under four levels of grazing intensities. We found dramatic changes in species composition in native small mammal communities when grazing intensity reached intermediate levels (0.46 animal unit/ha). As grazing intensity increased, Spermophilus dauricus gradually became the single dominant species. Species richness and diversity of small mammals in ungrazed and lightly grazed (0.23 animal unit/ha) area were much higher than in intermediately and heavily grazed area. We did not detect a humped relationship between small mammal diversity and disturbance levels predicted by the intermediate disturbance hypothesis (IDH). Our study highlighted the necessity of conducting manipulated experiments under multiple grazing intensities. PMID:27635323

  2. Specific features of oil biodegradation in meadow-chestnut soils of the Stavropol region (model experiment)

    NASA Astrophysics Data System (ADS)

    Ibatullina, I. Z.; Semenova, T. A.; Yakovlev, A. S.

    2012-03-01

    Oil biodegradation in oil-contaminated meadow-chestnut soils under the impact of different biological preparations was studied in a model experiment. The soils differed from one another in the age of contamination and in the presence/absence of the stage of preliminary biological remediation. Background uncontaminated soils served as the control. To characterize oil degradation, the indices of basal respiration (BR) and dehydrogenase activity (DA) and data on oil concentrations in the soil were applied. It was shown that the most complete biodegradation of oil takes place in the soils with recent oil contamination in comparison with the soils contaminated with oil for 6.5 and 19.5 months. Maximum BR values were observed in the soils contaminated with oil for 19.5 months, whereas maximum DA values were observed in the soils contaminated with oil for 6.5 months. According to the multivariate analysis of variance, the major factors affecting the rate of oil biodegradation were the age of oil contamination, the biological preparation applied, and the presence (or absence) of the stage of preliminary biological remediation. These factors specified 18, 72, and 3% of the total variance of the residual oil content in the samples, respectively. The type of the applied biological preparations had the major effect on the BR and DA indices specifying 63 and 53% of their total variances, respectively. The results obtained in this study can be used as recommendations for remediation of oil-contaminated soils in the Stavropol region.

  3. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain).

    PubMed

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988-1990 and 2009-2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

  4. Using biogeographical history to inform conservation: the case of Preble's meadow jumping mouse.

    PubMed

    Malaney, Jason L; Cook, Joseph A

    2013-12-01

    The last Pleistocene deglaciation shaped temperate and boreal communities in North America. Rapid northward expansion into high latitudes created distinctive spatial genetic patterns within species that include closely related groups of populations that are now widely spread across latitudes, while longitudinally adjacent populations, especially those near the southern periphery, often are distinctive due to long-term disjunction. Across a spatial expanse that includes both recently colonized and long-occupied regions, we analysed molecular variation in zapodid rodents to explore how past climate shifts influenced diversification in this group. By combining molecular analyses with species distribution modelling and tests of ecological interchangeability, we show that the lineage including the Preble's meadow jumping mouse (Zapus hudsonius preblei), a US federally listed taxon of conservation concern, is not restricted to the southern Rocky Mountains. Rather, populations along the Front Range are part of a single lineage that is ecologically indistinct and extends to the far north. Of the 21 lineages identified, this Northern lineage has the largest geographical range and low measures of intralineage genetic differentiation, consistent with recent northward expansion. Comprehensive sampling combined with coalescent-based analyses and niche modelling leads to a radically different view of geographical structure within jumping mice and indicates the need to re-evaluate their taxonomy and management. This analysis highlights a premise in conservation biology that biogeographical history should play a central role in establishing conservation priorities. PMID:24112356

  5. Global warming and soil microclimate: Results from a meadow-warming experiment

    SciTech Connect

    Harte, J.; Torn, M.S.; Chang, Fang-Ru; Feifarek, B.; Kinzig, A.P.; Shaw, R.; Shen, K.

    1995-02-01

    We used overhead infrared radiators to add a constant increment of {approx}15 W/m{sup 2}, over 2 yr, to the downward heat flux on five 30-m{sup 2} montane meadow plots in Gunnison County, Colorado, USA. Heating advanced snowmelt by {approx}1 wk, increased summer soil temperatures by up to 3{degrees}C, and reduced summer soil moisture levels by up to 25% compared to control plots. Soil microclimate response to heating varied with season, time of day, weather conditions, and location along the microclimate and vegetation gradient within each plot, with the largest temperature increase observed in daytime and in the drier, more sparsely vegetated zone of each plot. Day-to-day variation in the daily-averaged temperature response to heating in the drier zone was negatively correlated with that in the wetter zone. Our experimental manipulation provides a novel and effective method for investigating feedback processes linking climate, soil, and vegetation. 36 refs., 5 figs., 8 tabs.

  6. Day length and estradiol affect same-sex affiliative behavior in the female meadow vole.

    PubMed

    Beery, Annaliese K; Loo, Theresa J; Zucker, Irving

    2008-06-01

    Non-sexual social bonding between adult mammals is poorly understood, despite its importance in many species. Female meadow voles are territorial and nest alone in long summer day lengths when circulating estradiol concentrations are high, but cohabit in groups in short winter photoperiods when estradiol secretion is low. The influence of day length and estradiol on same-sex huddling behavior was assessed in adult female pairs housed together in long day lengths (LDs) or short day lengths (SDs) from weaning. The behavior of intact, ovariectomized, and estradiol-treated ovariectomized females from each photoperiod was assessed during 3 h partner-preference tests. Intact SD voles, unlike intact LD voles, spent the majority of the test in proximity to their cage-mates. Estradiol treatment of SD voles significantly reduced time spent huddling with the partner. Neither ovariectomy nor estradiol treatment significantly affected the amount of time LD females spent in contact with their partners. Low estradiol availability is therefore a necessary but not sufficient condition for maintenance of high levels of huddling. These results establish that ovarian hormones interact with photoperiod to affect same-sex social behavior.

  7. Day length and sociosexual cohabitation alter central oxytocin receptor binding in female meadow voles (Microtus pennsylvanicus).

    PubMed

    Parker, K J; Phillips, K M; Kinney, L F; Lee, T M

    2001-12-01

    In voles (Microtus), central oxytocin (OT) receptor patterns are associated with interspecific social organization. Social, monogamous voles have more OT receptors in the extended amygdala than asocial, nonmonogamous voles. Nonmonogamous meadow voles (Microtus pennsylvanicus), which exhibit seasonal changes in social organization (long day [LD] females are territorial, short day [SD] females live socially), provide a model for examining whether OT receptor patterns are associated with seasonal changes in intraspecific social behaviors. The authors examined whether sexually inexperienced (naive) SD females had more OT receptor binding than naive LD females. Naive SD females had greater OT receptor binding in the lateral septum (LS), lateral amygdala (LatAmyg), and central amygdala (CenAmyg) than less social, naive LD females. Because both SD and LD females acquire partner preferences, the authors assessed whether OT receptor binding was associated with partner preference onset. For LD females, partner preference onset corresponded with greater OT receptor binding in the anterior olfactory nucleus, LS, and bed nucleus of the stria terminalis, compared with naive LD females. In contrast, naive SD females and those exhibiting partner preferences did not differ. However, SD females that failed to acquire partner preferences showed less OT binding in the LatAmyg and CenAmyg. This study is the first to show that central OT receptor patterns are associated with seasonal changes in intraspecific social organization and partner preference onset in a nonmonogamous rodent.

  8. Rapid Assessment of Mineral Concentration in Meadow Grasses by Near Infrared Reflectance Spectroscopy

    PubMed Central

    Ward, Alastair; Nielsen, Anne Lisbeth; Møller, Henrik

    2011-01-01

    A near infrared reflectance spectroscopy (NIRS) method for rapid determination of nitrogen, phosphorous and potassium in diverse meadow grasses was developed with a view towards utilizing this material for biogas production and organic fertilizer. NIRS spectra between 12,000 cm−1 and 4,000 cm−1 were used. When validated on samples from different years to those used for the calibration set, the NIRS prediction of nitrogen was considered moderately useful with R2 = 0.77, ratio of standard error of prediction to reference data range (RER) of 9.32 and ratio of standard error of prediction to standard deviation of reference data (RPD) of 2.33. Prediction of potassium was less accurate, with R2 = 0.77, RER of 6.56 and RPD of 1.45, whilst prediction of phosphorous was not considered accurate enough to be of any practical use. This work is of interest from the point of view of both the removal of excess nutrients from formerly intensively farmed areas and also for assessing the plant biomass suitability for conversion into carbon neutral energy through biogas production. PMID:22163878

  9. Effects of cattle grazing on small mammal communities in the Hulunber meadow steppe

    PubMed Central

    Xin, Xiao-Ping; Liu, Zhi-Tao; Song, Yan-Ling

    2016-01-01

    Small mammals play important roles in many ecosystems, and understanding their response to disturbances such as cattle grazing is fundamental for developing sustainable land use strategies. However, how small mammals respond to cattle grazing remains controversial. A potential cause is that most of previous studies adopt rather simple experimental designs based solely on the presence/absence of grazing, and are thus unable to detect any complex relationships between diversity and grazing intensity. In this study, we conducted manipulated experiments in the Hulunber meadow steppe to survey small mammal community structures under four levels of grazing intensities. We found dramatic changes in species composition in native small mammal communities when grazing intensity reached intermediate levels (0.46 animal unit/ha). As grazing intensity increased, Spermophilus dauricus gradually became the single dominant species. Species richness and diversity of small mammals in ungrazed and lightly grazed (0.23 animal unit/ha) area were much higher than in intermediately and heavily grazed area. We did not detect a humped relationship between small mammal diversity and disturbance levels predicted by the intermediate disturbance hypothesis (IDH). Our study highlighted the necessity of conducting manipulated experiments under multiple grazing intensities.

  10. Genetic neighbourhood of clone structures in eelgrass meadows quantified by spatial autocorrelation of microsatellite markers.

    PubMed

    Hämmerli, A; Reusch, T B H

    2003-11-01

    Limited dispersal distances in plant populations frequently cause local genetic structure, which can be quantified by spatial autocorrelation. In clonal plants, three levels of spatial organization can contribute to positive autocorrelation; namely, the neighbourhood of (a) ramets, (b) clone fragments and (c) entire clones. Here we use data from an exhaustive sampling scheme on a clonal plant to measure the contribution of the neighbourhoods of each distinct clonal structure to total spatial autocorrelation. Four plots (256 grid points each) within dense meadows of the marine clonal plant Zostera marina (eelgrass) were sampled for clone structure with nine microsatellite markers ( approximately 80 alleles). We found significant coancestry (f(ij)), at all three levels of spatial organization, even when not allowing for joins between samples of identical genets. In addition, absolute values of f(ij) and the maximum distance with significant positive f(ij) decreased with the progressive exclusion of joins between alike genotypes. The neighbourhood of this clonal plant thus consists of three levels of organization, which are reflected in different kinship structures. Each of these kinship structures may affect the level of biparental inbreeding and the physical distance between flowering shoots and their outcrossing neighbourhood. These results also emphasize the notion that spatial autocorrelation crucially depends on the scale and intensity of sampling.

  11. Impacts of different climate change regimes and extreme climatic events on an alpine meadow community.

    PubMed

    Alatalo, Juha M; Jägerbrand, Annika K; Molau, Ulf

    2016-02-18

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity.

  12. Impacts of different climate change regimes and extreme climatic events on an alpine meadow community

    NASA Astrophysics Data System (ADS)

    Alatalo, Juha M.; Jägerbrand, Annika K.; Molau, Ulf

    2016-02-01

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity

  13. Complex responses of spring vegetation growth to climate in a moisture-limited alpine meadow.

    PubMed

    Ganjurjav, Hasbagan; Gao, Qingzhu; Schwartz, Mark W; Zhu, Wenquan; Liang, Yan; Li, Yue; Wan, Yunfan; Cao, Xujuan; Williamson, Matthew A; Jiangcun, Wangzha; Guo, Hongbao; Lin, Erda

    2016-01-01

    Since 2000, the phenology has advanced in some years and at some locations on the Qinghai-Tibetan Plateau, whereas it has been delayed in others. To understand the variations in spring vegetation growth in response to climate, we conducted both regional and experimental studies on the central Qinghai-Tibetan Plateau. We used the normalized difference vegetation index to identify correlations between climate and phenological greening, and found that greening correlated negatively with winter-spring time precipitation, but not with temperature. We used open top chambers to induce warming in an alpine meadow ecosystem from 2012 to 2014. Our results showed that in the early growing season, plant growth (represented by the net ecosystem CO2 exchange, NEE) was lower in the warmed plots than in the control plots. Late-season plant growth increased with warming relative to that under control conditions. These data suggest that the response of plant growth to warming is complex and non-intuitive in this system. Our results are consistent with the hypothesis that moisture limitation increases in early spring as temperature increases. The effects of moisture limitation on plant growth with increasing temperatures will have important ramifications for grazers in this system. PMID:26983697

  14. [Effects of nitrogen regulators on fertilizer nitrogen transformation in meadow cinnamon soil and on pakchoi growth].

    PubMed

    Sun, Zhi-Mei; Zhang, Kuo; Liu, Jian-Tao; Si, Huan-Sen; Wang, Yan-Qun

    2012-09-01

    Soil incubation test and pot experiment were conducted to investigate the effects of dicyandiamide (DCD) and its combination with nano-carbon on the transformation of fertilizers (urea and ammonium bicarbonate) nitrogen (N) in meadow cinnamon soil, a typical soil type in North China Plain, and on the growth of pakchoi (Brassica chinensis). In the first two weeks after applying urea and ammonium bicarbonate, the soil NH4+-N and NO3(-)-N contents varied greatly, but little variation was observed since then. The effects of the applied fertilizer N on the pakchoi growth and its N use efficiency differed significantly at early growth stages, but had little difference at harvesting stage. The DCD inhibited the transformation of the fertilizer N (especially ammonium bicarbonate N) into nitrate markedly, and this effect increased with increasing DCD dose. Under the conditions of our experiment, the optimal application rate of DCD was 1.0-1.5% of applied fertilize N, which could increase the pakchoi yield significantly, improve the leaf color, decrease the plant nitrate contents, and increase the fertilizer N use efficiency. The combination of DCD and nano-carbon exerted a synergistic effect on inhibiting soil ammonium oxidation, and also, promoted the pakchoi growth and N utilization at early growth stages significantly and decreased the plant nitrate level at harvesting stage.

  15. Transfer coefficient of 226Ra from vegetation to meadow voles, Microtus pennsylvanicus, on U mill tailings

    SciTech Connect

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

    1986-06-01

    The 226Ra level in vegetation growing on U mine tailings in Elliot Lake, Ontario, Canada, was 211 + 22 mBq g-1 (dry weight) compared to less than 7 mBq g-1 (dry weight) in material from a control site. Skeletons of meadow voles (Microtus pennsylvanicus) established on the tailings had concentrations of 226Ra of 6083 +/- 673 mBq per animal in winter; 7163 +/- 1077 mBq per animal in spring; 1506 +/- 625 mBq per animal in summer; and 703 +/- 59 mBq per animal in fall, compared to less than 7 mBq per animal in controls. The /sup 226/Ra transfer coefficient from vegetation to voles (defined as total millibecquerels of /sup 226/Ra in adult vole per total millibecquerels of 226Ra consumed by the vole in its lifetime) was calculated as 4.6 +/- 2.9 X 10(-2) in summer and 2.8 +/- 0.6 X 10(-2) in fall.

  16. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain)

    PubMed Central

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Abstract Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988–1990 and 2009–2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:25878552

  17. [Effects of nitrogen regulators on fertilizer nitrogen transformation in meadow cinnamon soil and on pakchoi growth].

    PubMed

    Sun, Zhi-Mei; Zhang, Kuo; Liu, Jian-Tao; Si, Huan-Sen; Wang, Yan-Qun

    2012-09-01

    Soil incubation test and pot experiment were conducted to investigate the effects of dicyandiamide (DCD) and its combination with nano-carbon on the transformation of fertilizers (urea and ammonium bicarbonate) nitrogen (N) in meadow cinnamon soil, a typical soil type in North China Plain, and on the growth of pakchoi (Brassica chinensis). In the first two weeks after applying urea and ammonium bicarbonate, the soil NH4+-N and NO3(-)-N contents varied greatly, but little variation was observed since then. The effects of the applied fertilizer N on the pakchoi growth and its N use efficiency differed significantly at early growth stages, but had little difference at harvesting stage. The DCD inhibited the transformation of the fertilizer N (especially ammonium bicarbonate N) into nitrate markedly, and this effect increased with increasing DCD dose. Under the conditions of our experiment, the optimal application rate of DCD was 1.0-1.5% of applied fertilize N, which could increase the pakchoi yield significantly, improve the leaf color, decrease the plant nitrate contents, and increase the fertilizer N use efficiency. The combination of DCD and nano-carbon exerted a synergistic effect on inhibiting soil ammonium oxidation, and also, promoted the pakchoi growth and N utilization at early growth stages significantly and decreased the plant nitrate level at harvesting stage. PMID:23286007

  18. Ovarian hormones influence odor cues emitted by female meadow voles, Microtus pennsylvanicus.

    PubMed

    Ferkin, M H; Gorman, M R; Zucker, I

    1991-12-01

    During the spring-summer breeding season female meadow voles emit odors that are preferred by males, whereas in the autumn-winter season of reproductive quiescence females emit odors that are not preferred by males, but are attractive to females. The effects of daylength and ovarian hormones on salience of female odors were determined by assaying male responses to odors. Females housed in long and short photoperiods transmitted odors that elicited responses similar to those of spring and autumn female voles, respectively. The odor cues emitted by ovariectomized (OVX) females, irrespective of photoperiodic history, were similar to those generated by females during the nonbreeding season. In the absence of ovarian hormones, long daylengths were not sufficient to induce females to broadcast the spring odors preferred by males. Spring-type odor cues were, however, emitted by OVX voles housed in either photoperiod and treated with estradiol. Ovarian hormones appear necessary and sufficient to generate breeding season odor cues and sufficient to induce production of such cues during the nonbreeding season. We conclude that daylength affects odor cues emitted by females by altering ovarian hormone activity. PMID:1813382

  19. Influence of gonadal hormones on odours emitted by male meadow voles (Microtus pennsylvanicus).

    PubMed

    Ferkin, M H; Gorman, M R; Zucker, I

    1992-08-01

    Free-living male meadow voles (Microtus pennsylvanicus) emit odours that are attractive to females at the beginning, but not at the end, of the breeding season. The effect of gonadal hormones on female-attractant cues was examined in males born and reared in long (14 h light day-1) and short (10 h light day-1) photoperiods that simulate daylengths in the breeding and nonbreeding seasons, respectively. Gonadectomy affected the attractant properties of odours emitted by long photoperiod, but not short photoperiod, males. Long photoperiod females preferred odours of intact rather than those of gonadectomized long photoperiod males, and odours of gonadectomized long photoperiod males rather than those of intact short photoperiod males. Females did not show a preference between the odours of intact and castrated short photoperiod males. Gonadal hormone replacement in males affected female responses to the odours emitted by long photoperiod, but not short photoperiod, gonadectomized males. Long photoperiod females did not display a preference between odours of intact long photoperiod males and gonadectomized long photoperiod males treated with testosterone or oestradiol. We conclude that in spring and summer gonadal hormones increase attractiveness of male odours; this effect may require aromatization of testosterone to oestradiol. Substrates that control attractiveness of odour cues in male voles appear to be unresponsive to androgens during the nonbreeding season. PMID:1404090

  20. Oxytocin and same-sex social behavior in female meadow voles.

    PubMed

    Beery, A K; Zucker, I

    2010-08-25

    The neuropeptide oxytocin (OT) has been implicated in a range of mammalian reproductive and social behaviors including parent-offspring bonding and partner preference formation between socially monogamous mates. Its role in mediating non-reproductive social relationships in rodents, however, remains largely unexplored. We examined whether OT facilitates same-sex social preferences between female meadow voles-a species that forms social nesting groups in short, winter-like day lengths. In contrast to results from studies of opposite-sex attachment between prairie vole mates, we found that neither OT nor dopamine neurotransmission was required for baseline levels of social partner preference formation or expression. OT enhanced preference formation beyond baseline levels-an effect that was counteracted by treatment with an oxytocin receptor antagonist (OTA). Oxytocin receptor (OTR) density correlated with social behavior in brain regions not known to be associated with opposite-sex affiliation, including the lateral septum and central amygdala. In addition, voles housed in short day lengths (SD) exhibited higher levels of OTR binding in the central amygdala, and voles exposed to high concentrations of estradiol exhibited less binding in the nucleus accumbens (NAcc) and increased binding in the ventromedial nucleus of the hypothalamus. These results suggest that same-sex social behavior shares common elements with other mammalian social behaviors affected by OT, but that the specific neural pathways through which OT exerts its influence are likely distinct from those known for sexual attachments. PMID:20580660

  1. Day length and estradiol affect same-sex affiliative behavior in the female meadow vole.

    PubMed

    Beery, Annaliese K; Loo, Theresa J; Zucker, Irving

    2008-06-01

    Non-sexual social bonding between adult mammals is poorly understood, despite its importance in many species. Female meadow voles are territorial and nest alone in long summer day lengths when circulating estradiol concentrations are high, but cohabit in groups in short winter photoperiods when estradiol secretion is low. The influence of day length and estradiol on same-sex huddling behavior was assessed in adult female pairs housed together in long day lengths (LDs) or short day lengths (SDs) from weaning. The behavior of intact, ovariectomized, and estradiol-treated ovariectomized females from each photoperiod was assessed during 3 h partner-preference tests. Intact SD voles, unlike intact LD voles, spent the majority of the test in proximity to their cage-mates. Estradiol treatment of SD voles significantly reduced time spent huddling with the partner. Neither ovariectomy nor estradiol treatment significantly affected the amount of time LD females spent in contact with their partners. Low estradiol availability is therefore a necessary but not sufficient condition for maintenance of high levels of huddling. These results establish that ovarian hormones interact with photoperiod to affect same-sex social behavior. PMID:18387611

  2. Sexual dimorphism in brain weight of meadow voles: role of gonadal hormones.

    PubMed

    Whaling, C S; Zucker, I; Wade, G N; Dark, J

    1990-05-01

    In most adult mammals, brain weights of males exceed those of females. The role of androgens in the genesis of this sex difference was assessed in meadow voles by acute neonatal or chronic postweaning manipulation of testosterone titers. Female voles given a single injection of testosterone propionate (TP) on the second day of postnatal life had brain weights in adulthood that were indistinguishable from those of male voles and significantly heavier than those of control females. Whole brain DNA content, a measure of cell number, was not increased by neonatal TP treatment. Females treated with TP from day 19 to 70 had lower brain weights than control females and males gonadectomized at 19 days of age had greater brain weights than did intact male voles at day 70. The sex dimorphism in brain weight reflects organizational effects of testosterone during perinatal development. Beginning at weaning, and continuing through postpubertal development, testosterone decreases brain weight in both sexes. We suggest that testosterone affects brain weight by altering cell size or non-cellular components rather than cell number. PMID:2192820

  3. Relative abundance and distribution of fishes and crayfish at Ash Meadows National Wildlife Refuge, Nye County, Nevada, 2007-08

    USGS Publications Warehouse

    Scoppettone, G. Gary; Rissler, Peter; Johnson, Danielle; Hereford, Mark

    2011-01-01

    This study provides baseline data of native and non-native fish populations in Ash Meadows National Wildlife Refuge (NWR), Nye County, Nevada, that can serve as a gauge in native fish enhancement efforts. In support of Carson Slough restoration, comprehensive surveys of Ash Meadows NWR fishes were conducted seasonally from fall 2007 through summer 2008. A total of 853 sampling stations were created using Geographic Information Systems and National Agricultural Imagery Program. In four seasons of sampling, Amargosa pupfish (genus Cyprinodon) was captured at 388 of 659 stations. The number of captured Amargosa pupfish ranged from 5,815 (winter 2008) to 8,346 (summer 2008). The greatest success in capturing Amargosa pupfish was in warm water spring-pools with temperature greater than 25 degrees C, headwaters of warm water spring systems, and shallow (depths less than 10 centimeters) grassy marshes. In four seasons of sampling, Ash Meadows speckled dace (Rhinichthys osculus nevadesis) was captured at 96 of 659 stations. The number of captured Ash Meadows speckled dace ranged from 1,009 (summer 2008) to 1,552 (winter 2008). The greatest success in capturing Ash Meadows speckled dace was in cool water spring-pools with temperature less than 20 degrees C and in the high flowing water outflows. Among 659 sampling stations within the range of Amargosa pupfish, red swamp crayfish (Procambarus clarkii) was collected at 458 stations, western mosquitofish (Gambusia affinis) at 374 stations, and sailfin molly (Poecilia latipinna) at 128 stations. School Springs was restored during the course of this study. Prior to restoration of School Springs, maximum Warm Springs Amargosa pupfish (Cyprinodon nevadensis pectoralis) captured from the six springs of the Warm Springs Complex was 765 (fall 2007). In four seasons of sampling, Warm Springs Amargosa pupfish were captured at 85 of 177 stations. The greatest success in capturing Warm Springs Amargosa pupfish when co-occurring with red

  4. Reciprocal Vegetation-Flow Feedbacks Driving Early-Stage Landscape Evolution in a Restored Wet Meadow

    NASA Astrophysics Data System (ADS)

    Larsen, L.; Merritts, D. J.; Walter, R. C.; Watts, D.

    2013-12-01

    Just as taxonomic classification has improved understanding in biology, ecogeomorphologists would benefit from a functional classification of biota based on the biophysical feedbacks that they engage in. Early stages of landscape development following disturbance provide a unique opportunity to delineate and understand these feedback processes, as the diversity in functional morphotypes (a.k.a. 'ecomorphs,' to expand on a concept from terrestrial ecology) is high and the potential for self-organization of landscape pattern strong. We used the opportunity of a stream restoration that reset its floodplain to 'initial conditions' to perform a suite of biophysical measurements designed to delineate the classes of feedback that influence landscape evolution in distinct ways. The Big Spring Run restoration (Lancaster, PA), completed in November 2011, involved removal of 15,000 t of legacy sediment from the valley bottom to expose a Holocene hydric layer and reestablish wet meadow hydrology and biota. By performing repeat biogeomorphic surveys within a study grid, we tested the hypothesis that distinct ecomorphs determine the persistence and location of channel and microtopographic features. The qualitatively distinct patch types surveyed included carpet-forming mat vegetation, tussock-forming vegetation, sparsely vegetated mudflats, benthic algal mats, mixed herbaceous communities, grasses, and clonal emergent vegetation. Within each sampling location, changes in vegetation community architecture, grain size distribution, critical shear stress for sediment entrainment, and topography were monitored over time, and flow resistance was measured. An overbank flow event that completely filled the floodplain provided an additional opportunity to measure vegetation-flow-sediment interactions. Once emergent vegetation was bent over by flow, vegetation had a negligible influence on flow velocity--in contrast to most other wetlands--but continued to shelter the bed from sediment

  5. Flowering phenology in subalpine meadows: does climate variation influence community co-flowering patterns?

    PubMed

    Forrest, Jessica; Inouye, David W; Thomson, James D

    2010-02-01

    Climate change is expected to alter patterns of species co-occurrence, in both space and time. Species-specific shifts in reproductive phenology may alter the assemblages of plant species in flower at any given time during the growing season. Temporal overlap in the flowering periods (co-flowering) of animal-pollinated species may influence reproductive success if competitive or facilitative interactions between plant species affect pollinator services. We used a 33-year data set on flowering phenology in subalpine meadows in Colorado, USA, to determine whether interannual variation in snowmelt date, which marks the start of the growing season, affected co-flowering patterns. For two of four species considered, we found a significant relationship between snowmelt timing and composition of the assemblage of co-flowering plants. In years of early snowmelt, Lathyrus lanszwertii var. leucanthus (Fabaceae), the species we investigated in most detail, tended to overlap with earlier-flowering species and with fewer species overall. In particular, overlap with the flowering period of Lupinus polyphyllus var. prunophilus, with which Lathyrus leucanthus shares pollinators, was significantly reduced in early-snowmelt years. The observed association between timing of snowmelt and patterns of flowering overlap could not have been predicted simply by examining temporal trends in the dates of peak flowering of the dominant species in the community, as peak flowering dates have largely shifted in parallel with respect to snowmelt date. However, subtle interspecific differences in responsiveness of flowering time, duration, and intensity to interannual climate variation have likely contributed to the observed relationship. Although much of the year-to-year variation in flowering overlap remains unexplained by snowmelt date, our finding of a measurable signal of climate variation suggests that future climate change may lead to altered competitive environments for these wildflower

  6. Spatially explicit feedbacks between seagrass meadow structure, sediment and light: Habitat suitability for seagrass growth

    NASA Astrophysics Data System (ADS)

    Carr, Joel A.; D'Odorico, Paolo; McGlathery, Karen J.; Wiberg, Patricia L.

    2016-07-01

    In shallow coastal bays where nutrient loading and riverine inputs are low, turbidity, and the consequent light environment are controlled by resuspension of bed sediments due to wind-waves and tidal currents. High sediment resuspension and low light environments can limit benthic primary productivity; however, both currents and waves are affected by the presence of benthic plants such as seagrass. This feedback between the presence of benthic primary producers such as seagrass and the consequent light environment has been predicted to induce bistable dynamics locally. However, these vegetated areas influence a larger area than they footprint, including a barren adjacent downstream area which exhibits reduced shear stresses. Here we explore through modeling how the patchy structure of seagrass meadows on a landscape may affect sediment resuspension and the consequent light environment due to the presence of this sheltered region. Heterogeneous vegetation covers comprising a mosaic of randomly distributed patches were generated to investigate the effect of patch modified hydrodynamics. Actual cover of vegetation on the landscape was used to facilitate comparisons across landscape realizations. Hourly wave and current shear stresses on the landscape along with suspended sediment concentration and light attenuation characteristics were then calculated and spatially averaged to examine how actual cover and mean water depth affect the bulk sediment and light environment. The results indicate that an effective cover, which incorporates the sheltering area, has important controls on the distributions of shear stress, suspended sediment, light environment, and consequent seagrass habitat suitability. Interestingly, an optimal habitat occurs within a depth range where, if actual cover is reduced past some threshold, the bulk light environment would no longer favor seagrass growth.

  7. Effect of experimental wood addition on hyporheic exchange and thermal dynamics in a losing meadow stream

    NASA Astrophysics Data System (ADS)

    Sawyer, Audrey H.; Cardenas, M. Bayani

    2012-10-01

    Stream restoration structures such as large wood can enhance shallow river-groundwater exchange, or hyporheic exchange, and alter temperature dynamics in restored reaches. We added and then removed channel-spanning logs in a second-order mountain meadow stream to test short-term impacts on hyporheic exchange, streambed temperatures, and surface water temperatures. Based on vertical seepage measurements and numerical simulations of hyporheic fluid and heat flow, large wood addition increased hyporheic exchange and altered streambed temperatures. In this losing stream, meter-scale hyporheic exchange cells formed beneath large wood. Upwelling pore water downstream of logs stabilized diel temperature cycles across <8% of the streambed, creating localized but potentially valuable thermal refuge. Exchange rates were <0.1% of channel discharge—too small to impact the range of diel temperature signals in surface water. However, the lag between downstream and upstream diel temperature signals was slightly greater with large wood, which may indicate that surface storage zones rather than hyporheic storage zones increased thermal retardation. Losing conditions limited the spatial extent and rates of hyporheic exchange near large wood. Impacts of large wood reintroduction on hyporheic exchange depend on ambient groundwater discharge or recharge, streambed permeability, channel Froude number, large wood blockage ratio, and large wood spacing. In many streams, large wood reintroduction may increase hyporheic habitat volume and complexity but may not increase exchange rates enough to alter surface water temperature or chemistry. Surface storage zones such as eddies and pools can still influence heat and solute retention in the channel.

  8. Comparison of Al speciation and other soil characteristics between meadow, young forest and old forest stands.

    PubMed

    Dlouhá, Sárka; Borůvka, Lubos; Pavlů, Lenka; Tejnecký, Václav; Drábek, Ondrej

    2009-11-01

    The aim of this paper is to describe the influence of spruce (Picea abies) afforestation on soil chemical properties, especially on soil acidity and aluminium (Al) mobilization and speciation in soil. For our study we used a unique set of three adjacent plots, including a meadow and two spruce forest stands of different age, in otherwise comparable conditions. The plots were located in the region of Giant Mountains, north-eastern Czech Republic. In general, pH values decreased and Al concentrations increased significantly after afforestation. Speciation of KCl-extractable and water-soluble Al in soil samples was done by means of HPLC/IC method. The concentrations of Al(X)(1+) and Al(Y)(2+) forms (in both extracts) are higher in humic and organically enriched (Bhs) horizons. The highest concentration of Al(3+) in both extracts is in the B horizons of old forest. Generally, in all studied stands majority of Al in aqueous extract is in the Al(X)(1+) form, which indicates that a large amount of mobile Al is bound in organic complexes. It suggests that actual toxicity is rather low. On the other hand, we have proved that majority of KCl-extractable Al exists in Al(3+) form. Thus we can conclude that disturbance of existing equilibrium may cause massive release of highly toxic Al(3+) from soil sorption complex to the soil solution, and consequently it can endanger the whole ecosystem. Moreover, continuous soil acidification accelerated by anthropogenic factors leading to Al mobilization represents a chemical time bomb. PMID:19748129

  9. Cascading effects of predator-detritivore interactions depend on environmental context in a Tibetan alpine meadow.

    PubMed

    Wu, Xinwei; Griffin, John N; Sun, Shucun

    2014-05-01

    Studies of grazing food webs show that species traits can interact with environmental factors to determine the strength of trophic cascades, but analogous context dependencies in detrital food webs remain poorly understood. In predator-detritivore-plant interaction chains, predators are expected to indirectly suppress plant biomass by reducing the density of plant-facilitating detritivores. However, this outcome can be reversed where above-ground predators drive burrowing detritivores to lower soil levels, strengthening their plant-facilitating effects. Here, we show that these trait-mediated indirect interactions further depend on environmental context in a Tibetan alpine meadow. In our study system, undulating topography generates higher (dry soil) patches interspersed with lower (wet soil) patches. Because the ability of detritivores to form deep burrows is likely to be limited by oxygen availability in low patches (wet soil), we hypothesized that (i) burrowing detritivores would undergo a vertical habitat shift, allowing them to more effectively avoid predation, in high - but not low - patches, and (ii) this shift would transmit positive effects of predators to plants in high patches by improving conditions in the lower soil layer. We tested these hypotheses using complementary field and glasshouse experiments examining whether the cascading effects of above-ground predatory beetles (presence/absence) on the density and behaviour of tunnel-forming detritivorous beetles, soil properties, and plant growth varied with patch type (low/high). Results revealed that predatory beetles did not reduce the density of detritivores in either patch type but had context-dependent trait-mediated effects, increasing the tunnelling depth of detritivores, improving soil conditions and ultimately increasing plant biomass in the high but not low patches. This study adds to an emerging predictive framework linking predators to plants in detritus food webs, demonstrating that these

  10. Evidence of Season-Dependency in Vegetation Effects on Macrofauna in Temperate Seagrass Meadows (Baltic Sea)

    PubMed Central

    Włodarska-Kowalczuk, Maria; Jankowska, Emilia; Kotwicki, Lech; Balazy, Piotr

    2014-01-01

    Seagrasses and associated macrophytes are important components of coastal systems as ecosystem engineers, habitat formers, and providers of food and shelter for other organisms. The positive impacts of seagrass vegetation on zoobenthic abundance and diversity (as compared to bare sands) are well documented, but only in surveys performed in summer, which is the season of maximum canopy development. Here we present the results of the first study of the relationship between the seasonal variability of seagrass vegetation and persistence and magnitude of contrasts in faunal communities between vegetated and bare sediments. The composition, abundance, biomass, and diversity of macrozoobenthos in both habitats were compared five times throughout the year in temperate eelgrass meadows in the southern Baltic Sea. Significant positive effects of macrophyte cover on invertebrate density and biomass were recorded only in June, July, and October when the seagrass canopy was relatively well developed. The effects of vegetation cover on faunal species richness, diversity, and composition persisted throughout the year, but the magnitude of these effects varied seasonally and followed changes in macrophyte biomass. The strongest effects were observed in July and coincided with maximums in seagrass biomass and the diversity and biomass of other macrophytes. These observations indicate that in temperate, clearly seasonal systems the assessment of macrophyte impact cannot be based solely on observations performed in just one season, especially when that season is the one in which macrophyte growth is at its maximum. The widely held belief that macrophyte cover strongly influences benthic fauna in marine coastal habitats, which is based on summer surveys, should be revisited and complemented with information obtained in other seasons. PMID:25000560

  11. Biodiversity management of fens and fen meadows by grazing, cutting and burning

    USGS Publications Warehouse

    Middleton, B.A.; Holsten, B.; Van Diggelen, R.

    2006-01-01

    Question: Can the biodiversity of fens in Europe and North America be maintained through the use of grazing (especially cattle grazing), fire, and/or cutting? Location: European and North American fens. Methods: This paper is a review of the literature on the effects of grazing, fire and cutting on fens, to explore the relationship between management and biodiversity in fens. Results: A reduction of cattle grazing, mowing and burning in fens has led to a reduction in biodiversity in fens. The vegetation of abandoned fens shifts to trees and shrubs after 10-15 years, which shade the smaller and rarer species of these wetlands. While careful use of fire is used to manage fens in North America, it is not widely used in European fens, perhaps because the peat of drained fens may catch fire. Cattle grazing cannot be considered a natural disturbance in North America, since cattle did not evolve on that continent. In Europe, cattle do not generally graze in unaltered fens, but they do use slightly drained fen meadows. Conclusions: Three approaches have been used to control the dominance of tall woody and herbaceous species in abandoned fens, including the re-introduction of cattle, mowing, and burning. Overgrazing results in a permanent reduction in biodiversity, therefore cattle re-introduction must be approached cautiously. In Europe, but not in North America, mowing has been an important management tool, and mowing has been successful in maintaining species richness, particularly in fens that have been mowed annually for centuries. Fire has been the most common and successful management tool in North America although it is not effective in removing shrubs that have become large. Because the problems and solutions are similar, the literature of both European and North American fen management can be analyzed to better assess the management of fens on both continents. Many management questions require further study and these are listed in the paper. ?? IAVS; Opulus Press.

  12. Age affects over-marking of opposite-sex scent marks in meadow voles, Microtus pennsylvanicus

    PubMed Central

    Ferkin, Michael H.

    2010-01-01

    Models of age-related effects on behavior predict that among short-lived species younger adults are more attractive and attracted to opposite-sex conspecifics than are older adults, whereas the converse is predicted for long-lived species. Although most studies of age-related effects on behavior support these predictions, they are not supported by many studies of scent marking, a behavior used in mate attraction. Over-marking, a form of scent marking, is a tactic used by many terrestrial mammals to convey information about themselves to opposite-sex conspecifics. The present study tested the hypothesis that the age of meadow voles, Microtus pennsylvanicus; a microtine rodent, affects their over- and scent marking behaviors when they encounter the marks of opposite-sex conspecifics. Sex differences existed in the over-marking behavior of adult voles among the three different age groups that were tested. Male voles that were 5-7 mo-old and 10-12 mo-old over-marked a higher proportion of the marks of females than did 2-3 mo-old male voles. Female voles that were 2-3 mo-old, 5-7 mo-old, and 10-12 mo-old over-marked a similar number of marks deposited by male voles. Overall, the data were not consistent with models predicting the behavior of short-lived animals such as rodents when they encounter the opposite sex. The differences in over-marking displayed by older and younger adult male voles may be associated with life history tradeoffs, the likelihood that they will encounter sexually receptive females, and being selected as mates. PMID:20607141

  13. Spatially explicit feedbacks between seagrass meadow structure, sediment and light: Habitat suitability for seagrass growth

    USGS Publications Warehouse

    Carr, Joel; D'Odorico, Paul; McGlathery, Karen; Wiberg, Patricia L.

    2016-01-01

    In shallow coastal bays where nutrient loading and riverine inputs are low, turbidity, and the consequent light environment are controlled by resuspension of bed sediments due to wind-waves and tidal currents. High sediment resuspension and low light environments can limit benthic primary productivity; however, both currents and waves are affected by the presence of benthic plants such as seagrass. This feedback between the presence of benthic primary producers such as seagrass and the consequent light environment has been predicted to induce bistable dynamics locally. However, these vegetated areas influence a larger area than they footprint, including a barren adjacent downstream area which exhibits reduced shear stresses. Here we explore through modeling how the patchy structure of seagrass meadows on a landscape may affect sediment resuspension and the consequent light environment due to the presence of this sheltered region. Heterogeneous vegetation covers comprising a mosaic of randomly distributed patches were generated to investigate the effect of patch modified hydrodynamics. Actual cover of vegetation on the landscape was used to facilitate comparisons across landscape realizations. Hourly wave and current shear stresses on the landscape along with suspended sediment concentration and light attenuation characteristics were then calculated and spatially averaged to examine how actual cover and mean water depth affect the bulk sediment and light environment. The results indicate that an effective cover, which incorporates the sheltering area, has important controls on the distributions of shear stress, suspended sediment, light environment, and consequent seagrass habitat suitability. Interestingly, an optimal habitat occurs within a depth range where, if actual cover is reduced past some threshold, the bulk light environment would no longer favor seagrass growth.

  14. Evidence of season-dependency in vegetation effects on macrofauna in temperate seagrass meadows (Baltic Sea).

    PubMed

    Włodarska-Kowalczuk, Maria; Jankowska, Emilia; Kotwicki, Lech; Balazy, Piotr

    2014-01-01

    Seagrasses and associated macrophytes are important components of coastal systems as ecosystem engineers, habitat formers, and providers of food and shelter for other organisms. The positive impacts of seagrass vegetation on zoobenthic abundance and diversity (as compared to bare sands) are well documented, but only in surveys performed in summer, which is the season of maximum canopy development. Here we present the results of the first study of the relationship between the seasonal variability of seagrass vegetation and persistence and magnitude of contrasts in faunal communities between vegetated and bare sediments. The composition, abundance, biomass, and diversity of macrozoobenthos in both habitats were compared five times throughout the year in temperate eelgrass meadows in the southern Baltic Sea. Significant positive effects of macrophyte cover on invertebrate density and biomass were recorded only in June, July, and October when the seagrass canopy was relatively well developed. The effects of vegetation cover on faunal species richness, diversity, and composition persisted throughout the year, but the magnitude of these effects varied seasonally and followed changes in macrophyte biomass. The strongest effects were observed in July and coincided with maximums in seagrass biomass and the diversity and biomass of other macrophytes. These observations indicate that in temperate, clearly seasonal systems the assessment of macrophyte impact cannot be based solely on observations performed in just one season, especially when that season is the one in which macrophyte growth is at its maximum. The widely held belief that macrophyte cover strongly influences benthic fauna in marine coastal habitats, which is based on summer surveys, should be revisited and complemented with information obtained in other seasons.

  15. The influence of hydrologic connectivity on ecosystem metabolism and nitrate uptake in an active beaver meadow

    NASA Astrophysics Data System (ADS)

    Wegener, P.; Covino, T. P.; Wohl, E.; Kampf, S. K.; Lacy, S.

    2015-12-01

    Wetlands have been widely demonstrated to provide important watershed services, such as the sequestration of carbon (C) and removal of nitrate (NO3-) from through-flowing water. Hydrologic connectivity (degree of water and associated material exchange) between floodplain water bodies (e.g., side channels, ponds) and the main channel influence rates of C accumulation and NO3- uptake, and the degree to which wetlands contribute to enhanced water quality at the catchment scale. However, environmental engineers have largely ignored the role of hydrologic connectivity in providing essential ecosystem services, and constructed wetlands are commonly built using compacted clay and berms that result in less groundwater and surface water exchange than observed in natural wetlands. In a study of an active beaver meadow (multithreaded, riparian wetland) in Rocky Mountain National Park, CO, we show how shifts in hydrology (connectivity, residence times, flow paths) from late spring snowmelt (high connectivity) to autumn/winter baseflow (low connectivity) influence ecosystem metabolism metrics (e.g., gross primary production, ecosystem respiration, and net ecosystem productivity) and NO3- uptake rates. We use a combination of mixing analyses, tracer tests, and hydrometric methods to evaluate shifts in surface and subsurface hydrologic connections between floodplain water bodies from snowmelt to baseflow. In the main channel and three floodplain water bodies, we quantify metabolism metrics and NO3- uptake kinetics across shifting flow regimes. Results from our research indicate that NO3- uptake and metabolism dynamics respond to changing levels of hydrologic connectivity to the main channel, emphasizing the importance of incorporating connectivity in wetland mitigation practices that seek to enhance water quality at the catchment scale.

  16. Monitoring soil moisture patterns in alpine meadows using ground sensor networks and remote sensing techniques

    NASA Astrophysics Data System (ADS)

    Bertoldi, Giacomo; Brenner, Johannes; Notarnicola, Claudia; Greifeneder, Felix; Nicolini, Irene; Della Chiesa, Stefano; Niedrist, Georg; Tappeiner, Ulrike

    2015-04-01

    Soil moisture content (SMC) is a key factor for numerous processes, including runoff generation, groundwater recharge, evapotranspiration, soil respiration, and biological productivity. Understanding the controls on the spatial and temporal variability of SMC in mountain catchments is an essential step towards improving quantitative predictions of catchment hydrological processes and related ecosystem services. The interacting influences of precipitation, soil properties, vegetation, and topography on SMC and the influence of SMC patterns on runoff generation processes have been extensively investigated (Vereecken et al., 2014). However, in mountain areas, obtaining reliable SMC estimations is still challenging, because of the high variability in topography, soil and vegetation properties. In the last few years, there has been an increasing interest in the estimation of surface SMC at local scales. On the one hand, low cost wireless sensor networks provide high-resolution SMC time series. On the other hand, active remote sensing microwave techniques, such as Synthetic Aperture Radars (SARs), show promising results (Bertoldi et al. 2014). As these data provide continuous coverage of large spatial extents with high spatial resolution (10-20 m), they are particularly in demand for mountain areas. However, there are still limitations related to the fact that the SAR signal can penetrate only a few centimeters in the soil. Moreover, the signal is strongly influenced by vegetation, surface roughness and topography. In this contribution, we analyse the spatial and temporal dynamics of surface and root-zone SMC (2.5 - 5 - 25 cm depth) of alpine meadows and pastures in the Long Term Ecological Research (LTER) Area Mazia Valley (South Tyrol - Italy) with different techniques: (I) a network of 18 stations; (II) field campaigns with mobile ground sensors; (III) 20-m resolution RADARSAT2 SAR images; (IV) numerical simulations using the GEOtop hydrological model (Rigon et al

  17. Estimates of ground-water discharge as determined from measurements of evapotranspiration, Ash Meadows area, Nye County, Nevada

    USGS Publications Warehouse

    Laczniak, R.J.; DeMeo, G.A.; Reiner, S.R.; Smith, Jody L.; Nylund, W.E.

    1999-01-01

    Ash Meadows is one of the major discharge areas within the regional Death Valley ground-water flow system of southern Nevada and adjacent California. Ground water discharging at Ash Meadows is replenished from inflow derived from an extensive recharge area that includes the eastern part of the Nevada Test Site (NTS). Currently, contaminants introduced into the subsurface by past nuclear testing at NTS are the subject of study by the U.S. Department of Energy's Environmental Restoration Program. The transport of any contaminant in contact with ground water is controlled in part by the rate and direction of ground-water flow, which itself depends on the location and quantity of ground water discharging from the flow system. To best evaluate any potential risk associated with these test-generated contaminants, studies were undertaken to accurately quantify discharge from areas downgradient from the NTS. This report presents results of a study to refine the estimate of ground-water discharge at Ash Meadows. The study estimates ground-water discharge from the Ash Meadows area through a rigorous quantification of evapotranspiration (ET). To accomplish this objective, the study identifies areas of ongoing ground-water ET, delineates unique areas of ET defined on the basis of similarities in vegetation and soil-moisture conditions, and computes ET rates for each of the delineated areas. A classification technique using spectral-reflectance characteristics determined from satellite images recorded in 1992 identified seven unique units representing areas of ground-water ET. The total area classified encompasses about 10,350 acres dominated primarily by lush desert vegetation. Each unique area, referred to as an ET unit, generally consists of one or more assemblages of local phreatophytes. The ET units identified range from sparse grasslands to open water. Annual ET rates are computed by energy-budget methods from micrometeorological measurements made at 10 sites within six

  18. Hydrologic effects of artificial-recharge experiments with reclaimed water at East Meadow, Long Island, New York

    USGS Publications Warehouse

    Schneider, B.J.; Ku, H.F.; Oaksford, E.T.

    1987-01-01

    Artificial recharge experiments were conducted at East Meadow, Long Island, New York, from October 1982 through January 1984 to evaluate the degree of groundwater mounding and the chemical effects of artificially replenishing the groundwater system with tertiary-treated wastewater. More than 800 million gallons of treated effluent was returned to the upper glacial aquifer through recharge basins and injection wells in the 15-month period. Reclaimed water was provided by the Cedar Creek advanced wastewater treatment facility in Wantagh, 6 miles away. The chlorinated effluent was pumped to the recharge facility, where it was fed to basins by gravity flow and to injection wells by pumps. Observations during the recharge tests indicate that the two most significant factors in limiting the rate of infiltration through the basin floor were the recharge test duration and quality of reclaimed water. Head buildup in the aquifer beneath the basins ranged from 4.3 to 6.7 ft, depending on the quantity and duration of water application. Head buildup near the injection wells within the aquifer ranged from 0.3 to 1.2 ft. Recharge basins provided a more effective means of moving large quantities of reclaimed water into the aquifer than injection wells. Results of 3-day and 176-day ponding tests in two basins indicate that reclaimed water is relatively unchanged chemically by percolation through the unsaturated zone because: (1) the sand and gravel of the upper glacial aquifer is unreactive, (2) the water moves to the water table rapidly, and (3) the water is highly treated before recharge. The quality of water in the aquifer zones affected by recharge improved, on the whole. Groundwater concentrations of nitrate nitrogen and several low molecular weight hydrocarbons, decreased to well within drinking water standards as a direct result of recharge. Sodium and chloride concentrations increased above background levels as a result of recharge but remained well within drinking water

  19. Eddy covariance measurements of carbon dioxide, latent and sensible energy fluxes above a meadow on a mountain slope

    PubMed Central

    Hammerle, Albin; Haslwanter, Alois; Schmitt, Michael; Bahn, Michael; Tappeiner, Ulrike; Cernusca, Alexander; Wohlfahrt, Georg

    2014-01-01

    Carbon dioxide, latent and sensible energy fluxes were measured by means of the eddy covariance method above a mountain meadow situated on a steep slope in the Stubai Valley/Austria, based on the hypothesis that, due to the low canopy height, measurements can be made in the shallow equilibrium layer where the wind field exhibits characteristics akin to level terrain. In order to test the validity of this hypothesis and to identify effects of complex terrain in the turbulence measurements, data were subjected to a rigorous testing procedure using a series of quality control measures established for surface layer flows. The resulting high-quality data set comprised 36 % of the original observations, the substantial reduction being mainly due to a change in surface roughness and associated fetch limitations in the wind sector dominating during nighttime and transition periods. The validity of the high-quality data set was further assessed by two independent tests: i) a comparison with the net ecosystem carbon dioxide exchange measured by means of ecosystem chambers and ii) the ability of the eddy covariance measurements to close the energy balance. The net ecosystem CO2 exchange measured by the eddy covariance method agreed reasonably with ecosystem chamber measurements. The assessment of the energy balance closure showed that there was no significant difference in the correspondence between the meadow on the slope and another one situated on flat ground at the bottom of the Stubai Valley, available energy being underestimated by 28 and 29 %, respectively. We thus conclude that, appropriate quality control provided, the eddy covariance measurements made above a mountain meadow on a steep slope are of similar quality as compared to flat terrain. PMID:24465032

  20. Stable Water Use Efficiency of Tibetan Alpine Meadows in Past Half Century: Evidence from Wool δ13C Values

    PubMed Central

    Yang, Hao; He, Nianpeng; He, Yongtao; Li, Shenggong; Shi, Peili; Zhang, Xianzhou

    2015-01-01

    Understanding the influences of climatic changes on water use efficiency (WUE) of Tibetan alpine meadows is important for predicting their long-term net primary productivity (NPP) because they are considered very sensitive to climate change. Here, we collected wool materials produced from 1962 to 2010 and investigated the long-term WUE of an alpine meadow in Tibet on basis of the carbon isotope values of vegetation (δ13Cveg). The values of δ13Cveg decreased by 1.34‰ during 1962–2010, similar to changes in δ13C values of atmospheric CO2. Carbon isotope discrimination was highly variable and no trend was apparent in the past half century. Intrinsic water use efficiency (Wi) increased by 18 μmol·mol–1 (approximately 23.5%) during 1962–2010 because the increase in the intercellular CO2 concentration (46 μmol·mol–1) was less than that in the atmospheric CO2 concentration (Ca, 73 μmol·mol–1). In addition, Wi increased significantly with increasing growing season temperature and Ca. However, effective water use efficiency (We) remained relatively stable, because of increasing vapor pressure deficit. Ca, precipitation, and growing season temperature collectively explained 45% of the variation of We. Our findings indicate that the We of alpine meadows in the Tibetan Plateau remained relatively stable by physiological adjustment to elevated Ca and growing season temperature. These findings improve our understanding and the capacity to predict NPP of these ecosystems under global change scenarios. PMID:26660306

  1. The performance, application and integration of various seabed classification systems suitable for mapping Posidonia oceanica (L.) Delile meadows.

    PubMed

    Puhr, Kristian; Schultz, Stewart; Pikelj, Kristina; Petricioli, Donat; Bakran-Petricioli, Tatjana

    2014-02-01

    In the context of current global environmental changes, mapping and monitoring seagrass meadows have become highly important for management and preservation of coastal zone ecosystems. The purpose of this research was to determine the numerical precision of various cost-effective benthic habitat mapping techniques and their suitability for mapping and monitoring of Posidonia oceanica meadows in the Croatian Adriatic. We selected ultra-high resolution aerial imagery, single-beam echo sounder (SBES) seabed classification system from Quester Tangent Co. (QTC), and surface based underwater videography as affordable, non-destructive and simple to use systems for data acquisition. The ultra-high resolution digital imagery was capable of detecting P. oceanica meadows up to 4m depth with 94% accuracy, from 4m to 12.5m depth the accuracy dropped to app. 76%, and from 12.5 to 20 m the system was only capable of distinguishing seabed biota from substrata, though with 97% accuracy. The results of the QTC system showed over 90% detection accuracy for Cymodocea nodosa covered seabed, excellent separation capabilities (>92%) of different sediment types (slightly gravelly sand, gravelly muddy sand and slightly gravelly muddy sand) and reasonable accuracy for mapping underwater vegetation regardless of the bathymetric span. The system proved incapable of separating P. oceanica from dense macroalgae on the same type of substratum. Surface-based underwater videography demonstrated great potential for estimating P. oceanica cover in a sampled region using either a single human rater or a computer estimate. The consistency between two human scorers in evaluating P. oceanica bottom coverage was near perfect (>98%) and high between digital and human scorers (80%). The results indicate that although the selected systems are suitable for mapping seagrasses, they all display limitations in either detection accuracy or spatial coverage, which leads to a conclusion that suitable system

  2. Breeding bird territory placement in riparian wet meadows in relation to invasive reed canary grass, Phalaris arundinacea

    USGS Publications Warehouse

    Kirsch, E.M.; Gray, B.R.; Fox, T.J.; Thogmartin, W.E.

    2007-01-01

    Invasive plants are a growing concern worldwide for conservation of native habitats. In endangered wet meadow habitat in the Upper Midwestern United States, reed canary grass (Phalaris arundinacea) is a recognized problem and its prevalence is more widespread than the better-known invasive wetland plant purple loosestrife (Lythrum salicaria). Although resource managers are concerned about the effect of reed canary grass on birds, this is the first study to report how common wet meadow birds use habitat in relation to reed canary grass cover and dominance. We examined three response variables: territory placement, size of territories, and numbers of territories per plot in relation to cover of reed canary grass. Territory locations for Sedge Wren (Cistothorus platensis) and Song Sparrow (Melospiza melodia) were positively associated with reed canary grass cover, while those for Common Yellowthroat (Geothlypis trichas) were not. Only Swamp Sparrow (M. georgiana) territory locations were negatively associated with reed canary grass cover and dominance (which indicated a tendency to place territories where there was no reed canary grass or where many plant species occurred with reed canary grass). Swamp Sparrow territories were positively associated with vegetation height density and litter depth. Common Yellowthroat territories were positively associated with vegetation height density and shrub cover. Song Sparrow territories were negatively associated with litter depth. Reed canary grass cover within territories was not associated with territory size for any of these four bird species. Territory density per plot was not associated with average reed canary grass cover of plots for all four species. Sedge Wrens and Song Sparrows may not respond negatively to reed canary grass because this grass is native to wet meadows of North America, and in the study area it merely replaces other tall lush plants. Avoidance of reed canary grass by Swamp Sparrows may be mediated

  3. The mapping of the Posidonia oceanica (L.) Delile barrier reef meadow in the southeastern Gulf of Tunis (Tunisia)

    NASA Astrophysics Data System (ADS)

    Hachani, Mohamed Amine; Ziadi, Boutheina; Langar, Habib; Sami, Djallouli Aslem; Turki, Souad; Aleya, Lotfi

    2016-09-01

    Barrier reefs are among the most important ecomorphosis for Posidonia oceanica meadows and have long been subjected to anthropic pressures. The authors mapped the entire Sidi Rais (northeastern Tunisia) Posidonia oceanica barrier reef by means of remote sensing based on processing a satellite image acquired via Google Earth © software, coupled with field observations obtained by snorkeling. The map thus produced represents the P. oceanica barrier reef in its current state, covering a total area of 156.77 ha, the reef being divided into three distinct sections separated by reverse flows with each section subject to varied anthropic factors and disturbances.

  4. Distribution and movement of Big Spring spinedace (Lepidomeda mollispinis pratensis) in Condor Canyon, Meadow Valley Wash, Nevada

    USGS Publications Warehouse

    Jezorek, Ian G.; Connolly, Patrick J.

    2013-01-01

    Big Spring spinedace (Lepidomeda mollispinis pratensis) is a cyprinid whose entire population occurs within a section of Meadow Valley Wash, Nevada. Other spinedace species have suffered population and range declines (one species is extinct). Managers, concerned about the vulnerability of Big Spring spinedace, have considered habitat restoration actions or translocation, but they have lacked data on distribution or habitat use. Our study occurred in an 8.2-km section of Meadow Valley Wash, including about 7.2 km in Condor Canyon and 0.8 km upstream of the canyon. Big Spring spinedace were present upstream of the currently listed critical habitat, including in the tributary Kill Wash. We found no Big Spring spinedace in the lower 3.3 km of Condor Canyon. We tagged Big Spring spinedace ≥70 mm fork length (range 70–103 mm) with passive integrated transponder tags during October 2008 (n = 100) and March 2009 (n = 103) to document movement. At least 47 of these individuals moved from their release location (up to 2 km). Thirty-nine individuals moved to Kill Wash or the confluence area with Meadow Valley Wash. Ninety-three percent of movement occurred in spring 2009. Fish moved both upstream and downstream. We found no movement downstream over a small waterfall at river km 7.9 and recorded only one fish that moved downstream over Delmue Falls (a 12-m drop) at river km 6.1. At the time of tagging, there was no significant difference in fork length or condition between Big Spring Spinedace that were later detected moving and those not detected moving. We found no significant difference in fork length or condition at time of tagging of Big Spring spinedace ≥70 mm fork length that were detected moving and those not detected moving. Kill Wash and its confluence area appeared important to Big Spring spinedace; connectivity with these areas may be key to species persistence. These areas may provide a habitat template for restoration or translocation. The lower 3.3 km of

  5. Comparison of field spectroradiometer and modis vegetation indices for estimating plant height in semi-natural meadows

    NASA Astrophysics Data System (ADS)

    Cunha, Mário; Pôças, Isabel; Marçal, André R. S.; Rodrigues, Arlete; Pereira, L. S.

    2010-05-01

    The main purpose of this work is to evaluate the most appropriate Vegetation Indices (VI) from MODIS (250 m resolution), to identify and assess the growth pattern of semi-natural meadows in northern Portugal. Sixteen-day MODIS-TERRA (250x250m) composites from 2001 to 2008 were used to examine the annual temporal profile of the NDVI and EVI, and their relationship with ground based observation of vegetation growth and reflectance inferred by spectroradiometer. The CORINE Land Cover maps from 2000 and information from field work were used to select suitable test sites, with at least 2x2 km mostly covered by semi-natural meadows. The whole site was considered as a unit, instead of using a pixel by pixel approach. This is done to prevent misregistration and other sources of errors to contaminate the temporal profiles. The median value of all pixels in each test site is used to compute the NDVI and EVI temporal profiles. Spectral measurements were performed monthly at field level using a handheld spectroradiometer (325nm and 1075nm). Eighteen campaigns of reflectance measurements were carried out in the period between July 2007 and December 2008, sampling all phenological stages of the semi-natural meadows. These field measurements were used to compute NDVI and EVI data using the information of bandwidth from MODIS. The Savitzky-Golay filter was used for smoothing the VI time series, as well as to extract a number of NDVI and EVI metrics by computing derivatives. The analysis of VI temporal profiles from different sensors showed more sensibility of the spectroradiometer to detected small in-season variations of growth, related with the pasture re-growth. Furthermore, the EVI from MODIS demonstrated more sensibility to detected re-growth than the NDVI. While both vegetation indices were sensitive to changes in plant height at the beginning of growing season, the NDVI became insensitive to additional growth when grass reached heights of 0.4 m (30% of maximum height). The

  6. Effect of Mid-summer Drought on Carbon Exchange in Subalpine Rocky Mountain Meadows

    NASA Astrophysics Data System (ADS)

    Sloat, L. L.; Henderson, A.; Enquist, B. J.

    2013-12-01

    higher peak NEE (p<0.05). Our results highlight the potential for an increasingly negative balance of carbon in subalpine meadows under future climate change.

  7. The effect of experimental ecosystem warming on CO2 fluxes in a montane meadow

    SciTech Connect

    Saleska, Scott R.; Harte, John; Torn, Margaret S.

    1997-07-01

    Climatic change is predicted to alter rates of soil respiration and assimilation of carbon by plants. Net loss of carbon from ecosystems would form a positive feedback enhancing anthropogenic global warming. We tested the effect of increased heat input, one of the most certain impacts of global warming, on net ecosystem carbon exchange in a Rocky Mountain montane meadow. Overhead heaters were used to increase the radiative heat flux into plots spanning a moisture and vegetation gradient. We measured net whole-ecosystem CO2 fluxes using a closed-path chamber system, relatively nondisturbing bases, and a simple model to compensate for both slow chamber leaks and the CO2 concentration-dependence of photosynthetic uptake, in 1993 and 1994. In 1994, we also measured soil respiration separately. The heating treatment altered the timing and magnitude of net carbon fluxes into the dry zone of the plots in 1993 (reducing uptake by 100 g carbon m2), but had an undetectable effect on carbon fluxes into the moist zone. During a strong drought year (1994), heating altered the timing, but did not significantly alter the cumulative magnitude, of net carbon uptake in the dry zone. Soil respiration measurements showed that when differences were detected in dry zone carbon fluxes, they were caused by changes in carbon input from photosynthesis, not by temperature-driven changes in carbon output from soil respiration. When differences were detected in dry-zone carbon fluxes, they were caused by changes in carbon input from photosynthesis, not by a temperature-driven changes in carbon output from soil respiration. Regression analysis suggested that the reduction in carbon inputs from plants was due to a combination of two soil moisture effects: a direct physiological response to decreased soil moisture, and a shift in plant community composition from high-productivity species to low-productivity species that are more drought tolerant. These results partially support predictions that

  8. [Responses of plant functional traits and soil factors to slope aspect in alpine meadow of South Gansu, Northwest China].

    PubMed

    Min-Xi, Liu; Jian-Zu, Ma

    2012-12-01

    This paper studied the plant functional traits, soil factors, and their relationships at different slope aspects in the alpine meadow of South Gansu. On the sunny slope, grasses were the dominant functional groups; while on the shady slope, forbs and shrubs dominated. The plant community biomass was significantly higher on shady slope than on sunny slope, while the leaf N/P ratio was in adverse. The leaf phosphorus content, specific leaf area, and plant average height at different slope aspects were in the order of shady slope > partial shady slope > sunny slope, whereas the leaf nitrogen content on different slopes had less difference. The survival strategies of the vegetations on sunny and shady slopes had great changes, reflecting in the differences in the plant leaf traits and dominant functional groups. Soil temperature was in the order of sunny slope > partial shady slope > shady slope, while soil water content was in the order of shady slope > partial shady slope > sunny slope. Soil total phosphorus content increased from the sunny slope to the shady slope, while the other soil nutrients contents showed the sequence of shady slope > sunny slope > partial shady slope. The specific leaf area and plant average height were significantly positively correlated to the soil organic carbon, total phosphorous, and water contents, and significantly negatively correlated to soil pH. Soil water content and soil pH co-affected the distribution patterns of plant functional traits and soil nutrients at different slope aspects of alpine meadow.

  9. Drying soil in North China drove the outbreak range expansion of meadow moth by facilitating long-distance migration

    PubMed Central

    Chen, Xiao; Jiang, Yuying; Kang, Aiguo; Zhai, Baoping

    2016-01-01

    Studies of the mechanism underlying the range expansion of organisms have mainly focused on environmental conditions at the edges of species’ distributions, potentially ignoring other possible factors. Here, we demonstrated the outbreak range expansion of meadow moth from North China to Northeast China in the past three outbreak periods. We found that the negligible infestation in Northeast China in the 1950s could not be explained by local climatic conditions. However, the soil moisture in North China decreased distinctly from 1951 to 2011 and was significantly and positively correlated with the timing of the first adult peak on plateaus, meaning that the deterioration of habitat conditions could result in earlier peaks of adults in areas of high-elevation by stimulating the short-distance dispersal of adults from the plains to the plateaus. Adults peaking earlier have a stronger tendency to emigrate due to mismatched phenology. Hence, drying soil in North China caused the frequent long-distance migration of meadow moth after the 1970s and drove the outbreak range expansion. This study suggests that, for a migratory species, the deterioration of habitat conditions in overwintering areas might also influence the distribution of this species in breeding areas at high latitudes by facilitating migration activities. PMID:27452616

  10. Drying soil in North China drove the outbreak range expansion of meadow moth by facilitating long-distance migration.

    PubMed

    Chen, Xiao; Jiang, Yuying; Kang, Aiguo; Zhai, Baoping

    2016-01-01

    Studies of the mechanism underlying the range expansion of organisms have mainly focused on environmental conditions at the edges of species' distributions, potentially ignoring other possible factors. Here, we demonstrated the outbreak range expansion of meadow moth from North China to Northeast China in the past three outbreak periods. We found that the negligible infestation in Northeast China in the 1950s could not be explained by local climatic conditions. However, the soil moisture in North China decreased distinctly from 1951 to 2011 and was significantly and positively correlated with the timing of the first adult peak on plateaus, meaning that the deterioration of habitat conditions could result in earlier peaks of adults in areas of high-elevation by stimulating the short-distance dispersal of adults from the plains to the plateaus. Adults peaking earlier have a stronger tendency to emigrate due to mismatched phenology. Hence, drying soil in North China caused the frequent long-distance migration of meadow moth after the 1970s and drove the outbreak range expansion. This study suggests that, for a migratory species, the deterioration of habitat conditions in overwintering areas might also influence the distribution of this species in breeding areas at high latitudes by facilitating migration activities. PMID:27452616

  11. Modeling land cover dynamics to assess the sustainability of wetland services: a case study of the Grand Lake Meadows, Canada

    NASA Astrophysics Data System (ADS)

    Shodimu, O.; Al-Tahir, Raid

    2016-04-01

    The Grand Lake Meadows is an important part of the Saint John River wetlands that form the largest freshwater wetland habitat in the Maritimes (eastern Canada). Changes in the land cover and use around wetlands significantly impact their biotic diversity, alter the ecosystem, and affect their ability to support human needs. The goal for this paper was to undertake a detailed and spatially explicit inventory of local trends in land use and land cover changes in Grand Lake Meadows over a 20-year time period. This goal was achieved through classifying historical remotely-sensed images to map the state of land use and cover. Other available data were combined with this information to create a database that was used to investigate the causes and consequences of changes. The results demonstrated the flexibility and the effectiveness of this technology in establishing the necessary baseline and support information for sustaining the eco-services of a wetland. The study identified a 38% decrease in the wetland from 1990 to 2001, while there was 80% increase in the wetland area since then. The result will help managers to comprehend the dynamics of the changes, prompting a better management and implementation of LULC administration in the area.

  12. An assessment of storage terms in the surface energy balance of a subalpine meadow in Northwest China

    NASA Astrophysics Data System (ADS)

    Wang, Runyuan; Zhang, Qiang

    2011-05-01

    The heat storage terms in the soil-vegetation-atmosphere system may play an important role in the surface energy budget. In this paper, we evaluate the heat storage terms of a subalpine meadow based on a field experiment conducted in the complex terrain of the eastern Qilian Mountains of Northwest China and their impact on the closure of the surface energy balance under such non-ideal conditions. During the night, the average sum of the storage terms was -5.5 W m-2, which corresponded to 10.4% of net radiation. The sum of the terms became positive at 0730 LST and negative again at about 1500 LST, with a maximum value of 19 W m-2 observed at approximately 0830 LST. During the day, the average of the sum of the storage terms was 6.5 Wm-2, which corresponded to 4.0% of net radiation. According to the slopes obtained when linear regression of the net radiation and partitioned fluxes was forced through the origin, there is an imbalance of 14.0% in the subalpine meadow when the storage terms are not considered in the surface energy balance. This imbalance was improved by 3.4% by calculating the sum of the storage terms. The soil heat storage flux gave the highest contribution (1.59%), while the vegetation enthalpy change and the rest of the storage terms were responsible for improvements of 1.04% and 0.77%, respectively.

  13. [Effects of plateau zokor disturbance and restoration years on soil nutrients and microbial functional diversity in alpine meadow].

    PubMed

    Hu, Lei; Ade, Lu-ji; Zi, Hong-biao; Wang, Chang-ting

    2015-09-01

    To explore the dynamic process of restoration succession in degraded alpine meadow that had been disturbed by plateau zokors in the eastern Tibetan Plateau, we examined soil nutrients and microbial functional diversity using conventional laboratory analysis and the Biolog-ECO microplate method. Our study showed that: 1) The zokors disturbance significantly reduced soil organic matter, total nitrogen, available nitrogen and phosphorus contents, but had no significant effects on soil total phosphorus and potassium contents; 2) Soil microbial carbon utilization efficiency, values of Shannon, Pielou and McIntosh indexes increased with alpine meadow restoration years; 3) Principal component analysis (PCA) showed that carbohydrates and amino acids were the main carbon sources for maintaining soil microbial community; 4) Redundancy analysis ( RDA) indicated that soil pH, soil organic matter, total nitrogen, available nitrogen, and total potassium were the main factors influencing the metabolic rate of soil microbial community and microbial functional diversity. In summary, variations in soil microbial functional diversity at different recovery stages reflected the microbial response to aboveground vegetation, soil microbial composition and soil nutrients.

  14. Drying soil in North China drove the outbreak range expansion of meadow moth by facilitating long-distance migration.

    PubMed

    Chen, Xiao; Jiang, Yuying; Kang, Aiguo; Zhai, Baoping

    2016-07-25

    Studies of the mechanism underlying the range expansion of organisms have mainly focused on environmental conditions at the edges of species' distributions, potentially ignoring other possible factors. Here, we demonstrated the outbreak range expansion of meadow moth from North China to Northeast China in the past three outbreak periods. We found that the negligible infestation in Northeast China in the 1950s could not be explained by local climatic conditions. However, the soil moisture in North China decreased distinctly from 1951 to 2011 and was significantly and positively correlated with the timing of the first adult peak on plateaus, meaning that the deterioration of habitat conditions could result in earlier peaks of adults in areas of high-elevation by stimulating the short-distance dispersal of adults from the plains to the plateaus. Adults peaking earlier have a stronger tendency to emigrate due to mismatched phenology. Hence, drying soil in North China caused the frequent long-distance migration of meadow moth after the 1970s and drove the outbreak range expansion. This study suggests that, for a migratory species, the deterioration of habitat conditions in overwintering areas might also influence the distribution of this species in breeding areas at high latitudes by facilitating migration activities.

  15. Influences of nitrogen, phosphorus and silicon addition on plant productivity and species richness in an alpine meadow.

    PubMed

    Xu, Danghui; Fang, Xiangwen; Zhang, Renyi; Gao, Tianpeng; Bu, Haiyan; Du, Guozhen

    2015-11-15

    Fertilization, especially with nitrogen (N), increases aboveground primary productivity (APP), but reduces plant species richness at some level. Silicon (Si) fertilization alone, or with addition of N or phosphorus (P), has multiple direct and indirect beneficial effects on plant growth and development, both for individuals and the whole community. This study aimed to examine the effects of Si, N, P, NSi and PSi combinations on APP and species richness of the community and of four functional groups in an alpine meadow. The results showed that plots fertilized with Si in combination with either N or P had higher APP than when fertilized with N or P alone. Addition of N or P increased APP, and the higher APP occurred when the highest level of N was added, indicating co-limitation of N and P, with N being most limiting. Silicon fertilization alone or with addition of N increased the APP of grasses and forbs. Nitrogen addition decreased the community species richness; Si with addition of N alleviated the loss of species richness of the whole community and the forbs group. For the four functional groups, N or P addition increased the species richness of grasses and decreased that of forbs. Our findings highlight the importance of Si in improving APP and alleviating N fertilization-induced biodiversity loss in grasslands, and will help improve our ability to predict community composition and biomass dynamics in alpine meadow ecosystems subject to changing nutrient availability.

  16. Influences of nitrogen, phosphorus and silicon addition on plant productivity and species richness in an alpine meadow

    PubMed Central

    Xu, Danghui; Fang, Xiangwen; Zhang, Renyi; Gao, Tianpeng; Bu, Haiyan; Du, Guozhen

    2015-01-01

    Fertilization, especially with nitrogen (N), increases aboveground primary productivity (APP), but reduces plant species richness at some level. Silicon (Si) fertilization alone, or with addition of N or phosphorus (P), has multiple direct and indirect beneficial effects on plant growth and development, both for individuals and the whole community. This study aimed to examine the effects of Si, N, P, NSi and PSi combinations on APP and species richness of the community and of four functional groups in an alpine meadow. The results showed that plots fertilized with Si in combination with either N or P had higher APP than when fertilized with N or P alone. Addition of N or P increased APP, and the higher APP occurred when the highest level of N was added, indicating co-limitation of N and P, with N being most limiting. Silicon fertilization alone or with addition of N increased the APP of grasses and forbs. Nitrogen addition decreased the community species richness; Si with addition of N alleviated the loss of species richness of the whole community and the forbs group. For the four functional groups, N or P addition increased the species richness of grasses and decreased that of forbs. Our findings highlight the importance of Si in improving APP and alleviating N fertilization-induced biodiversity loss in grasslands, and will help improve our ability to predict community composition and biomass dynamics in alpine meadow ecosystems subject to changing nutrient availability. PMID:26574603

  17. Population structure and secondary production of Siriella clausii, a dominant detritus feeding mysid in Posidonia oceanica meadows (W Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Barberá, Carmen; Sanchez-Jerez, Pablo; Sorbe, Jean Claude

    2013-10-01

    Temporal trends in abundance, demographic structure of the population and secondary production of Siriella clausii were studied at three different sectors of Posidonia oceanica meadows in the SE Iberian Peninsula, with different levels of habitat complexity. Secondary production was calculated through three methods widely employed in marine invertebrates: the Hynes method (based on demographic structure data) and models by Morin-Bourassa and Brey (based on biomass data). This filter/grazer and detritus feeder is the most abundant mysid in P. oceanica seagrass meadows in the Mediterranean. The population structure was similar in the three sectors, but the temporal pattern of abundance was different, at times even opposite. This pattern may be related to the aggregated spatial distribution, metapopulation dynamics or stochastic factors, but other potential factors could be involved, such as habitat features or predation rates. The values of production oscillated between 25 and 60 mgAFDW/m2/year, depending on the calculation method that was applied, and showed differences between sites and seagrass complexity. The present values are intermediate between those characterising highly productive systems, such as estuaries, and systems of limited productivity (bathyal habitats). Compared to other peracarids, mysid production is greater than that of isopods and less than amphipod production. This is possibly related to the life cycle and reproductive strategies. Detritus feeders such as S. clausii may play an important trophic role due their capacity to use as food the biomass associated to detritus, which constitutes larges reservoirs of carbon derived from seagrass primary production.

  18. Seasonal variability in sediment distribution along an exposure gradient in a seagrass meadow in Shoalwater Bay, Western Australia

    NASA Astrophysics Data System (ADS)

    Keulen, Mike van; Borowitzka, Michael A.

    2003-07-01

    Seagrasses, by blocking water flow as it passes through the leafy canopy, are believed to have a significant impact on sediment dynamics, and the formation of sand and mud banks in some areas. The role of seagrasses in sedimentation processes is poorly understood in high-energy environments, such as those found in south-Western Australia. Studies of sediment size fraction distribution were conducted over a 14-month period within a Posidonia sinuosa meadow, at an exposed and a sheltered site, to investigate the role of seagrass canopies on sediment dynamics. Sediment size analyses, obtained by sieving sediment samples, showed a difference between exposed and sheltered sites, as well as seasonal influences on the data. A three-way ANOVA run on the data indicates a summer and winter pattern superimposed over the sheltered and exposed pattern. This suggests that during the calmer conditions experienced in summer there was an increased proportion of finer grain sizes at the sheltered site, while in winter the grain sizes tended to become coarser, more closely matching the pattern observed at the exposed site. These results suggest that reduced water motion at the sheltered site during summer permitted finer sediment grain sizes to settle out, while increased water motion during winter increased the proportion of coarse grain sizes. At the exposed site this seasonal difference was not observed. It therefore appears that the P. sinuosa canopy reduces flow through a dense meadow, but this effect appears to be modified by overall wave energy, observed to operate seasonally.

  19. Effects of warming and grazing on soil N availability, species composition, and ANPP in an alpine meadow.

    PubMed

    Wang, Shiping; Duan, Jichuang; Xu, Guangping; Wang, Yanfen; Zhang, Zhenhua; Rui, Yichao; Luo, Caiyun; Xu, Burenbayin; Zhu, Xiaoxue; Chang, Xiaofeng; Cui, Xiaoyong; Niu, Haishan; Zhao, Xinquan; Wang, Wenying

    2012-11-01

    Uncertainty about the effects of warming and grazing on soil nitrogen (N) availability, species composition, and aboveground net primary production (ANPP) limits our ability to predict how global carbon sequestration will vary under future warming with grazing in alpine regions. Through a controlled asymmetrical warming (1.2/1.7 degrees C during daytime/nighttime) with a grazing experiment from 2006 to 2010 in an alpine meadow, we found that warming alone and moderate grazing did not significantly affect soil net N mineralization. Although plant species richness significantly decreased by 10% due to warming after 2008, we caution that this may be due to the transient occurrence or disappearance of some rare plant species in all treatments. Warming significantly increased graminoid cover, except in 2009, and legume cover after 2008, but reduced non-legume forb cover in the community. Grazing significantly decreased cover of graminoids and legumes before 2009 but increased forb cover in 2010. Warming significantly increased ANPP regardless of grazing, whereas grazing reduced the response of ANPP to warming. N addition did not affect ANPP in both warming and grazing treatments. Our findings suggest that soil N availability does not determine ANPP under simulated warming and that heavy grazing rather than warming causes degradation of the alpine meadows.

  20. A 5-Year Study of the Adult Flight Periodicity of 27 Caddisfly (Trichoptera) Species in Forest and Meadow Habitats of a First-Order Lower Michigan (USA) Stream.

    PubMed

    Houghton, David C

    2015-12-01

    Life cycles of 27 caddisfly species were estimated from weekly adult flight periodicity data during 2010-2014 from a forest and a meadow site of a small stream in northern Lower Michigan. Of the 11 species abundant only at the forest site, 10 appeared to be univoltine and 1 appeared bivoltine. Of the 13 species abundant only at the meadow site, 5 appeared univoltine, 5 appeared bivoltine, and 3 were enigmatic due to inconsistent flight peaks between years. Although the sites were separated by ∼400 m, only three species were abundant at both sites due to differences in stream habitat and food availability. Two of these species had notably dissimilar life cycles between sites, reflecting these differences. Despite the study dates encompassing both the warmest and coldest years of the 2000s, most species retained consistent flight periods between years. This consistency with date appeared unrelated to lunar phase. Date was a better predictor of flight periodicity than water temperature for every species except those that emerged earliest in the season. Warming water temperatures appeared to synchronize emergence of species at the meadow site to a greater degree than those of the forest site, probably due to the greater range of temperatures at the meadow site, although date was still the better predictor at both sites. These data suggest that warming water temperatures, although important under certain conditions, may not always be primary life cycle synchronizers in small streams.

  1. Promoting Pollinating Insects in Intensive Agricultural Matrices: Field-Scale Experimental Manipulation of Hay-Meadow Mowing Regimes and Its Effects on Bees

    PubMed Central

    Buri, Pierrick; Humbert, Jean-Yves; Arlettaz, Raphaël

    2014-01-01

    Bees are a key component of biodiversity as they ensure a crucial ecosystem service: pollination. This ecosystem service is nowadays threatened, because bees suffer from agricultural intensification. Yet, bees rarely benefit from the measures established to promote biodiversity in farmland, such as agri-environment schemes (AES). We experimentally tested if the spatio-temporal modification of mowing regimes within extensively managed hay meadows, a widespread AES, can promote bees. We applied a randomized block design, replicated 12 times across the Swiss lowlands, that consisted of three different mowing treatments: 1) first cut not before 15 June (conventional regime for meadows within Swiss AES); 2) first cut not before 15 June, as treatment 1 but with 15% of area left uncut serving as a refuge; 3) first cut not before 15 July. Bees were collected with pan traps, twice during the vegetation season (before and after mowing). Wild bee abundance and species richness significantly increased in meadows where uncut refuges were left, in comparison to meadows without refuges: there was both an immediate (within year) and cumulative (from one year to the following) positive effect of the uncut refuge treatment. An immediate positive effect of delayed mowing was also evidenced in both wild bees and honey bees. Conventional AES could easily accommodate such a simple management prescription that promotes farmland biodiversity and is likely to enhance pollination services. PMID:24416434

  2. Promoting pollinating insects in intensive agricultural matrices: field-scale experimental manipulation of hay-meadow mowing regimes and its effects on bees.

    PubMed

    Buri, Pierrick; Humbert, Jean-Yves; Arlettaz, Raphaël

    2014-01-01

    Bees are a key component of biodiversity as they ensure a crucial ecosystem service: pollination. This ecosystem service is nowadays threatened, because bees suffer from agricultural intensification. Yet, bees rarely benefit from the measures established to promote biodiversity in farmland, such as agri-environment schemes (AES). We experimentally tested if the spatio-temporal modification of mowing regimes within extensively managed hay meadows, a widespread AES, can promote bees. We applied a randomized block design, replicated 12 times across the Swiss lowlands, that consisted of three different mowing treatments: 1) first cut not before 15 June (conventional regime for meadows within Swiss AES); 2) first cut not before 15 June, as treatment 1 but with 15% of area left uncut serving as a refuge; 3) first cut not before 15 July. Bees were collected with pan traps, twice during the vegetation season (before and after mowing). Wild bee abundance and species richness significantly increased in meadows where uncut refuges were left, in comparison to meadows without refuges: there was both an immediate (within year) and cumulative (from one year to the following) positive effect of the uncut refuge treatment. An immediate positive effect of delayed mowing was also evidenced in both wild bees and honey bees. Conventional AES could easily accommodate such a simple management prescription that promotes farmland biodiversity and is likely to enhance pollination services.

  3. A 5-Year Study of the Adult Flight Periodicity of 27 Caddisfly (Trichoptera) Species in Forest and Meadow Habitats of a First-Order Lower Michigan (USA) Stream.

    PubMed

    Houghton, David C

    2015-12-01

    Life cycles of 27 caddisfly species were estimated from weekly adult flight periodicity data during 2010-2014 from a forest and a meadow site of a small stream in northern Lower Michigan. Of the 11 species abundant only at the forest site, 10 appeared to be univoltine and 1 appeared bivoltine. Of the 13 species abundant only at the meadow site, 5 appeared univoltine, 5 appeared bivoltine, and 3 were enigmatic due to inconsistent flight peaks between years. Although the sites were separated by ∼400 m, only three species were abundant at both sites due to differences in stream habitat and food availability. Two of these species had notably dissimilar life cycles between sites, reflecting these differences. Despite the study dates encompassing both the warmest and coldest years of the 2000s, most species retained consistent flight periods between years. This consistency with date appeared unrelated to lunar phase. Date was a better predictor of flight periodicity than water temperature for every species except those that emerged earliest in the season. Warming water temperatures appeared to synchronize emergence of species at the meadow site to a greater degree than those of the forest site, probably due to the greater range of temperatures at the meadow site, although date was still the better predictor at both sites. These data suggest that warming water temperatures, although important under certain conditions, may not always be primary life cycle synchronizers in small streams. PMID:26339996

  4. ARSENIC REMOVAL FROM DRINKING WATER BY ADSORPTIVE MEDIA. U.S. EPA DEMONSTRATION PROJECT AT SOUTH TRUCKEE MEADOWS GENERAL IMPROVEMENT DISTRICT (STMIG), NV. INTERIM EVALUATION REPORT

    EPA Science Inventory

    This report documents the activities performed during and the results obtained from the first 32 weeks of operation of an arsenic and antimony removal technology currently being demonstrated at the South Truckee Meadows General Improvement District (STMGID) in Washoe County, NV. ...

  5. Promoting pollinating insects in intensive agricultural matrices: field-scale experimental manipulation of hay-meadow mowing regimes and its effects on bees.

    PubMed

    Buri, Pierrick; Humbert, Jean-Yves; Arlettaz, Raphaël

    2014-01-01

    Bees are a key component of biodiversity as they ensure a crucial ecosystem service: pollination. This ecosystem service is nowadays threatened, because bees suffer from agricultural intensification. Yet, bees rarely benefit from the measures established to promote biodiversity in farmland, such as agri-environment schemes (AES). We experimentally tested if the spatio-temporal modification of mowing regimes within extensively managed hay meadows, a widespread AES, can promote bees. We applied a randomized block design, replicated 12 times across the Swiss lowlands, that consisted of three different mowing treatments: 1) first cut not before 15 June (conventional regime for meadows within Swiss AES); 2) first cut not before 15 June, as treatment 1 but with 15% of area left uncut serving as a refuge; 3) first cut not before 15 July. Bees were collected with pan traps, twice during the vegetation season (before and after mowing). Wild bee abundance and species richness significantly increased in meadows where uncut refuges were left, in comparison to meadows without refuges: there was both an immediate (within year) and cumulative (from one year to the following) positive effect of the uncut refuge treatment. An immediate positive effect of delayed mowing was also evidenced in both wild bees and honey bees. Conventional AES could easily accommodate such a simple management prescription that promotes farmland biodiversity and is likely to enhance pollination services. PMID:24416434

  6. Twelve Months of Air Quality Monitoring at Ash Meadows National Wildlife Refuge, Southwestern Rural Nevada, U.S.A (EMSI April 2007)

    SciTech Connect

    Engelbrecht, Johann P; Shafer, David S; Campbell, Dave; Campbell, Scott; McCurdy, Greg; Kohl, Steven D; Nikolich, George; Sheetz, Larry

    2011-08-01

    The one year of air quality monitoring data collected at the Ash Meadows National Wildlife Refuge (NWR) was the final part of the air quality "Scoping Studies" for the Environmental Monitoring Systems Initiative (EMSI) in southern and central Nevada. The objective of monitoring at Ash Meadows was to examine aerosol and meteorological data, seasonal trends in aerosol and meteorological parameters as well as to examine evidence for long distance transport of some constituents. The 9,307 hectare refuge supports more than 50 springs and 24 endemic species, including the only population of the federally listed endangered Devil’s Hole pupfish (Cyprinodon diabolis) (U.S. Fish and Wildlife Service, 1990). Ash Meadows NWR is located in a Class II air quality area, and the aerosol measurements collected with this study are compared to those of Interagency Monitoring of Protected Visual Environments (IMPROVE) sites. Measurements taken at Ash Meadows NWR over a period of 12 months provide new baseline air quality and meteorological information for rural southwestern Nevada, specifically Nye County and the Amargosa Valley.

  7. Gopher eskers, mounds, and stonelines: Evidence of the annual to centennial impacts of gophers in the montane meadows of Colorado's Front Range

    NASA Astrophysics Data System (ADS)

    Winchell, E. W.; Lombardi, E. M.; Marquez, J. A.; Doak, D. F.; Anderson, R. S.

    2014-12-01

    Within the critical zone on montane hillslopes of Colorado's Front Range, qualitative observations suggest that gophers not only dominate the modern meadow geomorphic rates, but are involved in a geomorphic-ecological feedback system that governs meadow migration on decadal-millennial time scales. Our observations suggest that gopher intensity and location is pertinent to forest/meadow (FM) dynamics. Field mapping of gopher activity as the snow melts in the spring revealed that subnivean tubes ("eskers") are tightly clustered at the FM boundary while mounds generated over the remainder of the summer are concentrated strictly in the meadows. This suggests that gophers spend the winter months at the FM interface and spend the warmer seasons within the meadows. We hypothesize that variations in snow depth drive this spatial-temporal pattern of gopher activity; deeper snow near the FM boundary provides greater insulation, as near-surface ground temperatures in the wind-scoured meadow centers are colder. This motivates our initiation of monitoring and modeling of near-surface temperature across a FM pair. Numerical modeling supports qualitative observations that the following geomorphic-ecological processes are active: seedling establishment and damage, gopher tunneling and resulting mound generation, mound material transport driven by ungulate trampling, vegetative lock-down of mound material, and resulting changes in the soil depth of the landscape. This year's observations suggest that we must add to this mix the annual cycle of the gopher activity. Finally, probing and soil pits within the meadows reveal that on longer timescales gopher activity leads to the development of a well-mixed upper soil layer that is sharply bounded below by high concentrations of large stones ("stone lines") within the glacial till substrate of the hillslopes. The mean diameter of mound surface grains is half that of clasts comprising the stone lines. This motivates documentation of soil

  8. Geophysical Studies Based on Gravity and Seismic Data of Tule Desert, Meadow Valley Wash, and California Wash Basins, Southern Nevada

    USGS Publications Warehouse

    Scheirer, Daniel S.; Page, William R.; Miller, John J.

    2006-01-01

    Gravity and seismic data from Tule Desert, Meadow Valley Wash, and California Wash, Nevada, provide insight into the subsurface geometry of these three basins that lie adjacent to rapidly developing areas of Clark County, Nevada. Each of the basins is the product of Tertiary extension accommodated with the general form of north-south oriented, asymmetrically-faulted half-grabens. Geophysical inversion of gravity observations indicates that Tule Desert and Meadow Valley Wash basins are segmented into subbasins by shallow, buried basement highs. In this study, basement refers to pre-Cenozoic bedrock units that underlie basins filled with Cenozoic sedimentary and volcanic units. In Tule Desert, a small, buried basement high inferred from gravity data appears to be a horst whose placement is consistent with seismic reflection and magnetotelluric observations. Meadow Valley Wash consists of three subbasins separated by basement highs at structural zones that accommodated different styles of extension of the adjacent subbasins, an interpretation consistent with geologic mapping of fault traces oblique to the predominant north-south fault orientation of Tertiary extension in this area. California Wash is a single structural basin. The three seismic reflection lines analyzed in this study image the sedimentary basin fill, and they allow identification of faults that offset basin deposits and underlying basement. The degree of faulting and folding of the basin-fill deposits increases with depth. Pre-Cenozoic units are observed in some of the seismic reflection lines, but their reflections are generally of poor quality or are absent. Factors that degrade seismic reflector quality in this area are rough land topography due to erosion, deformed sedimentary units at the land surface, rock layers that dip out of the plane of the seismic profile, and the presence of volcanic units that obscure underlying reflectors. Geophysical methods illustrate that basin geometry is more

  9. Mercury concentrations in largemouth bass (Micropterus salmoides) collected from Ash Meadows National Wildlife Refuge, Nye County, Nevada.

    PubMed

    Goodchild, Shawn; Gerstenberger, Shawn

    2011-04-01

    Mercury is a known neurotoxin and contaminant of concern worldwide. Mercury may occur at elevated concentrations adjacent to industrial sources, such as coal-fired power plants, or in remote environments and newly filled water bodies. Mercury tissue concentrations were determined for a sample of largemouth bass (Micropterus salmoides) from Crystal Reservoir, Ash Meadows National Wildlife Refuge, Nye County, Nevada. This investigation was triggered by (1) the presence of several conditions in soil and water that facilitate mercury bioaccumulation, (2) previous investigations that detected mercury in source springs, and (3) the presence of game fish and endangered pupfish within the reservoir. Mercury concentrations were significantly correlated with both fish mass and condition, but were lower than national human health and safety standards. It is possible that high pH and salinity inhibited methylation and subsequent bioaccumulation; however, additional studies are needed to determine causation of the low concentration in fish tissue compared with ambient conditions.

  10. Towards adaptive management of the natural capital: Disentangling trade-offs among marine activities and seagrass meadows.

    PubMed

    Bas Ventín, Leticia; de Souza Troncoso, Jesús; Villasante, Sebastián

    2015-12-15

    This paper investigates the ecological, social and institutional dimensions of the synergies and trade-offs between seagrasses and human activities operating in the Natura 2000 protected site of San Simón Bay (Galicia, NW Spain). By means of a multidisciplinary approach that brings together the development of a biological inventory combined with participatory mapping processes we get key spatial and contextual understanding regarding how, where and why marine users interact with seagrasses and how seagrasses are considered in policy making. The results highlight the fisheries' reliance on seagrass meadows and the controversial links with shellfisheries. The study also reveals unresolved conflicts among those management plans that promote the protection of natural values and those responsible for the exploitation of marine resources. We conclude that the adoption of pre-planning bottom-up participatory processes is crucial for the design of realistic strategies where both seagrasses and human activities were considered as a couple system.

  11. Towards adaptive management of the natural capital: Disentangling trade-offs among marine activities and seagrass meadows.

    PubMed

    Bas Ventín, Leticia; de Souza Troncoso, Jesús; Villasante, Sebastián

    2015-12-15

    This paper investigates the ecological, social and institutional dimensions of the synergies and trade-offs between seagrasses and human activities operating in the Natura 2000 protected site of San Simón Bay (Galicia, NW Spain). By means of a multidisciplinary approach that brings together the development of a biological inventory combined with participatory mapping processes we get key spatial and contextual understanding regarding how, where and why marine users interact with seagrasses and how seagrasses are considered in policy making. The results highlight the fisheries' reliance on seagrass meadows and the controversial links with shellfisheries. The study also reveals unresolved conflicts among those management plans that promote the protection of natural values and those responsible for the exploitation of marine resources. We conclude that the adoption of pre-planning bottom-up participatory processes is crucial for the design of realistic strategies where both seagrasses and human activities were considered as a couple system. PMID:26589639

  12. Lead poisoning of northern pintail ducks feeding in a tidal meadow contaminated with shot from a trap and skeet range

    SciTech Connect

    Roscoe, D.E.; Widjeskog, L.; Stansley, W.

    1989-02-01

    Lead poisoning of waterfowl from the ingestion of lead shot is well documented and widespread throughout the United States. Research and remedial regulations have focused on waterfowl hunting as the major source of this lead shot. Mortalities of cattle from ingestion of silage contaminated with lead shot from trap shooting have been documented in the United States, the United Kingdom and Ireland. Although ingestion of lead shot by cattle grazing on silage from a trap range was documented in Denmark, no mortalities were reported. This paper describes lead poisoning of northern pintail ducks (Anas acuta) from ingestion of lead shot deposited on a tidal meadow as the result of trap and skeet shooting. This is the first published report linking trap and skeet shooting with lead poisoning of waterfowl. It also describes and evaluates the management procedures taken to prevent the poisonings.

  13. Relationship between wind and seagrass meadows in a non-tidal eutrophic lagoon studied by a Wave Exposure Model (WEMo).

    PubMed

    Rubegni, Fabrizio; Franchi, Enrica; Lenzi, Mauro

    2013-05-15

    The hydrodynamic action of wind and the distribution of biomass of seagrass meadows in a non-tidal eutrophic lagoon (Orbetello Lagoon, Tuscany, Italy) were analysed for correlations by simulation with a Wave Exposure Model (WEMo) on 5-year data series. WEMo and statistical analysis established a weak direct correlation between the areas that the model identified as being subject to resuspension and transport of sediment and those actually colonised by seagrass. A significant difference was found between surface and bottom hydrodynamics. The areas that the model identified as exposed to higher energy surface hydrodynamics proved to be inversely correlated with seagrass biomass. Multivariate statistical analysis ordered the model variables according to their relative importance. The model indicated the need for further study, demonstrating its utility for environmental management of eutrophic lagoons. PMID:23522697

  14. Sensitivity analysis of a soil-vegetation-atmosphere transfer (SVAT) model parameterised for a British floodplain meadow

    NASA Astrophysics Data System (ADS)

    Morris, P. J.; Verhoef, A.; Van der Tol, C.; Macdonald, D.

    2011-12-01

    Rationale: Floodplain meadows are highly species-rich grassland ecosystems, unique in that their vegetation and soil structures have been shaped and maintained by ~1,000 yrs of traditional, low-intensity agricultural management. Widespread development on floodplains over the last two centuries has left few remaining examples of these once commonplace ecosystems and they are afforded high conservation value by British and European agencies. Increased incidences and severity of summer drought and winter flooding in Britain in recent years have placed floodplain plant communities under stress through altered soil moisture regimes. There is a clear need for improved management strategies if the last remaining British floodplain meadows are to be conserved under changing climates. Aim: As part of the Floodplain Underground Sensors Experiment (FUSE, a 3-year project funded by the Natural Environment Research Council) we aim to understand the environmental controls over soil-vegetation-atmosphere transfers (SVAT) of water, CO2 and energy at Yarnton Mead, a floodplain meadow in southern England. An existing model, SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes; van der Tol et al., 2009), uses remotely-sensed infrared radiance spectra to predict heat and water transfers between a vegetation canopy and the atmosphere. We intend to expand SCOPE by developing a more realistic, physically-based representation of water, gas and energy transfers between soil and vegetation. This improved understanding will eventually take the form of a new submodel within SCOPE, allowing more rigorous estimation of soil-canopy-atmosphere exchanges for the site using predominantly remotely-sensed data. In this context a number of existing SVAT models will be tested and compared to ensure that only reliable and robust underground model components will be coupled to SCOPE. Approach: For this study, we parameterised an existing and widely-used SVAT model (CoupModel; Jansson, 2011

  15. Effects of Warming on CO2 Fluxes in an Alpine Meadow Ecosystem on the Central Qinghai-Tibetan Plateau.

    PubMed

    Ganjurjav, Hasbagan; Gao, Qingzhu; Zhang, Weina; Liang, Yan; Li, Yawei; Cao, Xujuan; Wan, Yunfan; Li, Yue; Danjiu, Luobu

    2015-01-01

    To analyze CO2 fluxes under conditions of climate change in an alpine meadow on the central Qinghai-Tibetan Plateau, we simulated the effect of warming using open top chambers (OTCs) from 2012 to 2014. The OTCs increased soil temperature by 1.62°C (P < 0.05), but decreased soil moisture (1.38%, P < 0.05) during the experiments. The response of ecosystem CO2 fluxes to warming was variable, and dependent on the year. Under conditions of warming, mean gross ecosystem productivity (GEP) during the growing season increased significantly in 2012 and 2014 (P < 0.05); however, ecosystem respiration (ER) increased substantially only in 2012 (P < 0.05). The net ecosystem CO2 exchange (NEE) increased marginally in 2012 (P = 0.056), did not change in 2013(P > 0.05), and increased significantly in 2014 (P = 0.034) under conditions of warming. The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under warming in the alpine meadow. Under warming, the 3-year averages of GEP, ER, and NEE increased by 19.6%, 15.1%, and 21.1%, respectively. The seasonal dynamic patterns of GEP and NEE, but not ER, were significantly impacted by warming. Aboveground biomass, particularly the graminoid biomass increased significantly under conditions of warming. Soil moisture, soil temperature, and aboveground biomass were the main factors that affected the variation of the ecosystem CO2 fluxes. The effect of warming on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to warming, require further researched. PMID:26147223

  16. Insect emergence in relation to floods in wet meadows and swamps in the River Dalälven floodplain.

    PubMed

    Vinnersten, T Z Persson; Östman, Ö; Schäfer, M L; Lundström, J O

    2014-08-01

    Annual variation in flood frequency and hydroperiod during the vegetation season has ecological impacts on the floodplain biota. Although many insect groups may have a lower emergence during a flood event, it is poorly known how annual emergence of insects in temporary wetlands is related to the variation in hydrology. Between May and September, we studied the weekly emergence of 18 insect taxa over six consecutive years, 2002-2007, in six temporary flooded wetlands (four wet meadows and two forest swamps) in the River Dalälven floodplains, Central Sweden. We used emergence traps to collect emerging insects from terrestrial and aquatic parts of wet meadows and swamp forests. In all wetlands, the insect fauna was numerically dominated by the orders Diptera, Hymenoptera, Coleoptera and Homoptera. On a weekly basis, 9 out of the 18 insect taxa had lower emergence in weeks with flood than in weeks with no flood, whereas no taxon had a higher emergence in weeks with flood. Over the seasons, we related insect emergence to seasonal flood frequency and length of hydroperiod. The emergence of most studied taxa decreased with increasing hydroperiod, which suggests that emergence after floods do not compensate for the reduced emergence during floods. Only Culicidae and the aquatic Chironomidae sub-families Tanypodinae and Chironominae showed an increase in emergence with increasing hydroperiod, whereas Staphylinidae peaked at intermediate hydroperiod. We conclude that a hydroperiod covering up to 40% of the vegetation season has a significant negative effect on the emergence of most taxa and that only a few taxa occurring in the temporary wetlands are actually favoured by a flood regime with recurrent and unpredictable floods. PMID:24521711

  17. Insect emergence in relation to floods in wet meadows and swamps in the River Dalälven floodplain.

    PubMed

    Vinnersten, T Z Persson; Östman, Ö; Schäfer, M L; Lundström, J O

    2014-08-01

    Annual variation in flood frequency and hydroperiod during the vegetation season has ecological impacts on the floodplain biota. Although many insect groups may have a lower emergence during a flood event, it is poorly known how annual emergence of insects in temporary wetlands is related to the variation in hydrology. Between May and September, we studied the weekly emergence of 18 insect taxa over six consecutive years, 2002-2007, in six temporary flooded wetlands (four wet meadows and two forest swamps) in the River Dalälven floodplains, Central Sweden. We used emergence traps to collect emerging insects from terrestrial and aquatic parts of wet meadows and swamp forests. In all wetlands, the insect fauna was numerically dominated by the orders Diptera, Hymenoptera, Coleoptera and Homoptera. On a weekly basis, 9 out of the 18 insect taxa had lower emergence in weeks with flood than in weeks with no flood, whereas no taxon had a higher emergence in weeks with flood. Over the seasons, we related insect emergence to seasonal flood frequency and length of hydroperiod. The emergence of most studied taxa decreased with increasing hydroperiod, which suggests that emergence after floods do not compensate for the reduced emergence during floods. Only Culicidae and the aquatic Chironomidae sub-families Tanypodinae and Chironominae showed an increase in emergence with increasing hydroperiod, whereas Staphylinidae peaked at intermediate hydroperiod. We conclude that a hydroperiod covering up to 40% of the vegetation season has a significant negative effect on the emergence of most taxa and that only a few taxa occurring in the temporary wetlands are actually favoured by a flood regime with recurrent and unpredictable floods.

  18. Agricultural Activities of a Meadow Eliminated Plant Litter from the Periphery of a Farmland in Inner Mongolia, China

    PubMed Central

    Kawada, Kiyokazu; Borjigin, Wuyunna; Nakamura, Toru

    2015-01-01

    The purpose of our investigation was to clarify the effects of agriculture on the process of loss of litter at the periphery of a farmland. This study revealed the generation process of an ecologically unusual phenomenon that is observed around cropland in semi-arid regions. We hypothesized that the vegetation around a farmland cannot supply plant litter to the ground surface because the ecological structure has been changed by agricultural activities. The study was conducted at Xilingol steppe, Xilingol League, Inner Mongolia Autonomous Region, China. Four study lines were established from the edge of an arable field to the surrounding meadow and parallel to the wind direction during the strong wind season. Key measurement for each line was set at the border between the farmland and steppe. Four study sites were set at intervals along each line. Plant litter, soil particle size distribution, plant species composition, plant volume, and species diversity were investigated. Despite using the same mowing method at the meadows of all study sites, the litter at the only periphery of the farmland completely disappeared. Soil particle size distribution in steppe, which was adjacent to the farmland, was similar to that of the farmland. Plant community structure at the periphery of the farmland was different from that of the far side from the farmland. This implies that soil scattered from the farmland affected the species composition of the steppe. Consequently, the change in plant community structure induced litter loss because of mowing. We concluded that plant litter was lost near the farmland because of the combined effects of farming and mowing. The results support our hypothesis that the vegetation around a farmland cannot supply plant litter because the ecological structure has been changed by agricultural activities. PMID:26241943

  19. Effects of Simulated Nitrogen Deposition on Soil Net Nitrogen Mineralization in the Meadow Steppe of Inner Mongolia, China.

    PubMed

    Liu, Xing-Ren; Ren, Jian-Qiang; Li, Sheng-Gong; Zhang, Qing-Wen

    2015-01-01

    Effects of simulated nitrogen (N) deposition on soil net nitrogen mineralization (NNM) were examined in situ during two growing seasons, using the resin-core technique in the semiarid meadow steppe in Inner Mongolia, China. The aim of this study is to clarify the effect of N levels (0, 10, and 20 kg N ha-1yr-1) and forms (NH4+ and NO3-) on soil mineral N and NNM. Our results showed that N levels had no significant differences on soil mineral N and NNM. In the first year, three N treatments ((NH4)2SO4, NH4Cl and KNO3) increased soil NH4+ concentrations but had no significant effects on soil NO3- concentrations. In the second year, (NH4)2SO4 treatment increased soil NO3- concentrations, NH4Cl and KNO3 treatments decreased them. Three N treatments significantly decreased soil NH4+ concentrations in the later stages of the second year. As for the soil NNM, three N treatments had no significant effects on the rates of soil NNM (Rm) and net nitrification (Rn) in the first year, but significantly decreased them in the second year. The contribution of N addition to Rm was higher from (NH4)2SO4 than from NH4Cl and KNO3. However, Soil Rm was mainly affected by soil water content (SWC), accumulated temperature (Ta), and soil total N (TN). These results suggest that the short-term atmospheric N deposition may inhibit soil NNM in the meadow steppe of Inner Mongolia. PMID:26218275

  20. Effects of Simulated Nitrogen Deposition on Soil Net Nitrogen Mineralization in the Meadow Steppe of Inner Mongolia, China

    PubMed Central

    Liu, Xing-ren; Ren, Jian-qiang; Li, Sheng-gong; Zhang, Qing-wen

    2015-01-01

    Effects of simulated nitrogen (N) deposition on soil net nitrogen mineralization (NNM) were examined in situ during two growing seasons, using the resin-core technique in the semiarid meadow steppe in Inner Mongolia, China. The aim of this study is to clarify the effect of N levels (0, 10, and 20 kg N ha−1yr−1) and forms (NH4+ and NO3-) on soil mineral N and NNM. Our results showed that N levels had no significant differences on soil mineral N and NNM. In the first year, three N treatments ((NH4)2SO4, NH4Cl and KNO3) increased soil NH4+ concentrations but had no significant effects on soil NO3- concentrations. In the second year, (NH4)2SO4 treatment increased soil NO3- concentrations, NH4Cl and KNO3 treatments decreased them. Three N treatments significantly decreased soil NH4+ concentrations in the later stages of the second year. As for the soil NNM, three N treatments had no significant effects on the rates of soil NNM (Rm) and net nitrification (Rn) in the first year, but significantly decreased them in the second year. The contribution of N addition to Rm was higher from (NH4)2SO4 than from NH4Cl and KNO3. However, Soil Rm was mainly affected by soil water content (SWC), accumulated temperature (Ta), and soil total N (TN). These results suggest that the short-term atmospheric N deposition may inhibit soil NNM in the meadow steppe of Inner Mongolia. PMID:26218275

  1. Effects of Warming on CO2 Fluxes in an Alpine Meadow Ecosystem on the Central Qinghai-Tibetan Plateau.

    PubMed

    Ganjurjav, Hasbagan; Gao, Qingzhu; Zhang, Weina; Liang, Yan; Li, Yawei; Cao, Xujuan; Wan, Yunfan; Li, Yue; Danjiu, Luobu

    2015-01-01

    To analyze CO2 fluxes under conditions of climate change in an alpine meadow on the central Qinghai-Tibetan Plateau, we simulated the effect of warming using open top chambers (OTCs) from 2012 to 2014. The OTCs increased soil temperature by 1.62°C (P < 0.05), but decreased soil moisture (1.38%, P < 0.05) during the experiments. The response of ecosystem CO2 fluxes to warming was variable, and dependent on the year. Under conditions of warming, mean gross ecosystem productivity (GEP) during the growing season increased significantly in 2012 and 2014 (P < 0.05); however, ecosystem respiration (ER) increased substantially only in 2012 (P < 0.05). The net ecosystem CO2 exchange (NEE) increased marginally in 2012 (P = 0.056), did not change in 2013(P > 0.05), and increased significantly in 2014 (P = 0.034) under conditions of warming. The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under warming in the alpine meadow. Under warming, the 3-year averages of GEP, ER, and NEE increased by 19.6%, 15.1%, and 21.1%, respectively. The seasonal dynamic patterns of GEP and NEE, but not ER, were significantly impacted by warming. Aboveground biomass, particularly the graminoid biomass increased significantly under conditions of warming. Soil moisture, soil temperature, and aboveground biomass were the main factors that affected the variation of the ecosystem CO2 fluxes. The effect of warming on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to warming, require further researched.

  2. Using Seismic Refraction and Ground Penetrating Radar (GPR) to Characterize the Valley Fill in Beaver Meadows, Rocky Mountain National Park

    NASA Astrophysics Data System (ADS)

    Kramer, N.; Harry, D. L.; Wohl, E. E.

    2010-12-01

    This study is one of the first to use near surface geophysical techniques to characterize the subsurface stratigraphy in a high alpine, low gradient valley with a past glacial history and to obtain a preliminary grasp on the impact of Holocene beaver activity. Approximately 1 km of seismic refraction data and 5 km of GPR data were collected in Beaver Meadows, Rocky Mountain National Park. An asymmetric wedge of sediment ranging in depth from 0-20 m transverse to the valley profile was identified using seismic refraction. Complementary analysis of the GPR data suggests that the valley fill can be subdivided into till deposited during the Pleistocene glaciations and alluvium deposited during the Holocene. Two main facies were identified in the GPR profiles through pattern recognition. Facie Fd, which consists of chaotic discontinuous reflectors with an abundance of diffractions, is interpreted to be glacial till. Facie Fc, which is a combination of packages of complex slightly continuous reflectors interfingered with continuous horizontal to subhorizontal reflectors, is interpreted to be post-glacial alluvium and includes overbank, pond and in-channel deposits. Fc consistently overlies Fd throughout the study area and is no more than 7 m thick in the middle of the valley. The thickness of Holocene sedimentation (<7 m) is much less than the total amount of valley fill identified in the seismic refraction survey (0-20 m). A subfacie of Fc, Fch, which has reflectors with long periods was identified within Fc and is interpreted to be ponded sediments. The spatial distribution of facie Fch, along with: slight topographical features resembling buried beaver dams, a high abundance of fine sediment including silts and clays, historical records of beavers, and the name "Beaver Meadows" all suggest that Holocene beaver activity played a large role in sediment accumulation at this site, despite the lack of surficial relict beaver dams containing wood.

  3. Effects of Simulated Nitrogen Deposition on Soil Net Nitrogen Mineralization in the Meadow Steppe of Inner Mongolia, China.

    PubMed

    Liu, Xing-Ren; Ren, Jian-Qiang; Li, Sheng-Gong; Zhang, Qing-Wen

    2015-01-01

    Effects of simulated nitrogen (N) deposition on soil net nitrogen mineralization (NNM) were examined in situ during two growing seasons, using the resin-core technique in the semiarid meadow steppe in Inner Mongolia, China. The aim of this study is to clarify the effect of N levels (0, 10, and 20 kg N ha-1yr-1) and forms (NH4+ and NO3-) on soil mineral N and NNM. Our results showed that N levels had no significant differences on soil mineral N and NNM. In the first year, three N treatments ((NH4)2SO4, NH4Cl and KNO3) increased soil NH4+ concentrations but had no significant effects on soil NO3- concentrations. In the second year, (NH4)2SO4 treatment increased soil NO3- concentrations, NH4Cl and KNO3 treatments decreased them. Three N treatments significantly decreased soil NH4+ concentrations in the later stages of the second year. As for the soil NNM, three N treatments had no significant effects on the rates of soil NNM (Rm) and net nitrification (Rn) in the first year, but significantly decreased them in the second year. The contribution of N addition to Rm was higher from (NH4)2SO4 than from NH4Cl and KNO3. However, Soil Rm was mainly affected by soil water content (SWC), accumulated temperature (Ta), and soil total N (TN). These results suggest that the short-term atmospheric N deposition may inhibit soil NNM in the meadow steppe of Inner Mongolia.

  4. Mohawk Lake or Mohawk meadow Sedimentary facies and stratigraphy of Quaternary deposits in Mohawk Valley, upper Middle Fork of the Feather River, California

    SciTech Connect

    Yount, J.C. ); Harwood, D.S. ); Bradbury, J.P. )

    1993-04-01

    Mohawk Valley (MV) contain thick, well-exposed sections of Quaternary basin-fill sediments, with abundant interbedded tephra and a diverse assemblage of sedimentary facies. The eastern arm of MV, extending from Clio to Portola, contains as much as 100 m of trough cross-bedded cobble to pebble gravel and planar and trough cross-bedded coarse and medium sand, interpreted as braided stream deposits. Sections exposed in the western arm of MV consist in their lower parts of massive organic-rich silt and clay interbedded with blocky to fissile peat beds up to 1 m thick. Diatom assemblages are dominated by benthic species indicating fresh marsh environments with very shallow water depths of one meter or less. Proglacial lacustrine deposits of limited lateral extent are present within the outwash complexes as evidenced by varved fine sand and silt couplets, poorly sorted quartz-rich silt beds containing dropstones, and contorted beds of diamict grading laterally into slump blocks surrounded by wood-bearing silt and silty sand. The Rockland Ash (400 ka) is a prominent marker in the middle or lower part of many sections throughout MV, indicating that at least half of the basin-fill sequence is Late Quaternary in age. A log buried in diamict slumped into a proglacial lake lying approximately 3 km downstream from the Tioga Stage ice termini in Jamison and Gray Eagle Creeks yields an age of 18,715 [+-]235 C[sup 14] years BP. Previous interpretations of MV deposits originating in a large, deep lake with water depths in excess of 150 m are untenable given the sedimentary facies and diatom floras that dominate the valley. Unexhumed valleys such as Sierra Valley to the east and Long Valley to the northwest which contain large meadows traversed by braided streams are probably good analogs for the conditions that existed during the accumulation of the Mohawk Valley deposits.

  5. Air Pollution and Acid Rain, Report 8. Effects of air pollution and acid rain on fish, wildlife, and their habitats: arctic tundra and alpine meadows

    SciTech Connect

    Olson, J.E.; Adler, D.

    1982-06-01

    This report on arctic tundra and alpine meadow ecosystems is part of a series synthesizing the results of scientific research related to the effects of air pollution and acid deposition on fish and wildlife resources. Recently performed research reveals the growing air pollution problem in arctic tundra and alpine meadow ecosystems once thought to be relatively unpolluted. The ecosystem features which determine sensitivity to air pollution are described. Data related to the effects of air pollutants on biota and whole ecosystems are reviewed. Because very little work has been done on the effects of air pollution specifically in arctic and alpine ecosystems this report includes relevant information based on studies in other ecosystems. Suggestions are made for areas of further research. 68 references, 2 figures.

  6. Evaluation of management practices in wetland meadows at Grays Lake National Wildlife Refuge, Idaho, 1997-2000

    USGS Publications Warehouse

    Austin, J.E.; Pyle, W.H.; Keough, J.R.; Johnson, D.H.

    2002-01-01

    We assessed the relative values of 4 management practices (idle, late season grazing, fall prescribed burning, and rotation of idle and summer grazing) to biotic resources of the grassland-wetland meadow ecosystem at Grays Lake during 1997-2000. Three replicates of each treatment were randomly assigned to 12 experimental units that bordered the deep emergent marsh. Biotic factors examined included the breeding bird community and abundance, nesting activity and nest success, small mammal abundance, plant community, and annual plant biomass production. Fall burns achieved treatment objectives, removing most residual vegetation across a range of cover types. Objectives for grazing treatments were mostly attained; however, vegetation use levels were insufficient for consistent attainment of treatment objectives. Savannah sparrow, American coot, Canada goose, sandhill crane, mallard, and yellow-headed blackbird were the most common bird species present. Densities of 2 bird species (savannah sparrow and red-winged blackbird) were related to year effect only. The effect of unit on densities of redhead, lesser scaup, ruddy duck, sora, long-billed curlew, and common snipe likely reflects habitat differences among units. Densities of 6 species (eared grebe, canvasback, American coot, American avocet, willet, and common yellowthroat) were related to both year and unit effects. Treatment affected densities of 6 of the 29 species examined (mallard, northern shoveler, cinnamon teal, blue-winged teal, American crow, and yellow-headed blackbird); we found no common trend in response to treatments among those species. Overall, idled habitat did not stand out to be a valuable treatment, whereas grazing tended to have positive responses for a number of species. Burning was more likely to result in reduced bird densities than other treatments. We also describe the distribution of species observations among 8 different habitat types. Of the 23 nesting species sampled in the

  7. Effects of rodent-induced land degradation on ecosystem carbon fluxes in an alpine meadow in the Qinghai-Tibet Plateau, China

    NASA Astrophysics Data System (ADS)

    Peng, F.; Quangang, Y.; Xue, X.; Guo, J.; Wang, T.

    2015-03-01

    The widespread land degradation in an alpine meadow ecosystem would affect ecosystem carbon (C) balance. Biomass, soil chemical properties and carbon dioxide (CO2) of six levels of degraded lands (D1-D6, according to the number of rodent holes and coverage) were investigated to examine the effects of rodent-induced land degradation on an alpine meadow ecosystem. Soil organic carbon (SOC), labile soil carbon (LC), total nitrogen (TN) and inorganic nitrogen (N) were obtained by chemical analysis. Soil respiration (Rs), net ecosystem exchange (NEE) and ecosystem respiration (ER) were measured by a Li-Cor 6400XT. Gross ecosystem production (GEP) was the sum of NEE and ER. Aboveground biomass (AGB) was based on a linear regression with coverage and plant height as independent variables. Root biomass (RB) was obtained by using a core method. Soil respiration, ER, GEP and AGB were significantly higher in slightly degraded (D3 and D6, group I) than in severely degraded land (D1, D2, D4 and D5, group II). Positive values of NEE average indicate that the alpine meadow ecosystem is a weak C sink during the growing season. The only significant difference was in ER among different degradation levels. Rs, ER and GEP were 38.2, 44.3 and 46.5% higher in group I than in group II, respectively. Similar difference of ER and GEP between the two groups resulted in an insignificant difference of NEE. Positive correlations of AGB with ER, NEE and GEP, and relatively small AGB and lower CO2 fluxes in group II, suggest the control of AGB on ecosystem CO2 fluxes. Correlations of RB with SOC, LC, TN and inorganic N indicate the regulation of RB on soil C and N with increasing number of rodent holes in an alpine meadow ecosystem in the permafrost region of the Qinghai-Tibet Plateau (QTP).

  8. Effects of nitrogen and phosphorus fertilization on soil carbon fractions in alpine meadows on the Qinghai-Tibetan Plateau.

    PubMed

    Li, Jin Hua; Yang, Yu Jie; Li, Bo Wen; Li, Wen Jin; Wang, Gang; Knops, Johannes M H

    2014-01-01

    In grassland ecosystems, N and P fertilization often increase plant productivity, but there is no concensus if fertilization affects soil C fractions. We tested effects of N, P and N+P fertilization at 5, 10, 15 g m-2 yr-1 (N5, N10, N15, P5, P10, P15, N5P5, N10P10, and N15P15) compared to unfertilized control on soil C, soil microbial biomass and functional diversity at the 0-20 cm and 20-40 cm depth in an alpine meadow after 5 years of continuous fertilization. Fertilization increased total aboveground biomass of community and grass but decreased legume and forb biomass compared to no fertilization. All fertilization treatments decreased the C:N ratios of legumes and roots compared to control, however fertilization at rates of 5 and 15 g m-2 yr-1 decreased the C:N ratios of the grasses. Compared to the control, soil microbial biomass C increased in N5, N10, P5, and P10 in 0-20 cm, and increased in N10 and P5 while decreased in other treatments in 20-40 cm. Most of the fertilization treatments decreased the respiratory quotient (qCO2) in 0-20 cm but increased qCO2 in 20-40 cm. Fertilization increased soil microbial functional diversity (except N15) but decreased cumulative C mineralization (except in N15 in 0-20 cm and N5 in 20-40 cm). Soil organic C (SOC) decreased in P5 and P15 in 0-20 cm and for most of the fertilization treatments (except N15P15) in 20-40 cm. Overall, these results suggested that soils will not be a C sink (except N15P15). Nitrogen and phosphorus fertilization may lower the SOC pool by altering the plant biomass composition, especially the C:N ratios of different plant functional groups, and modifying C substrate utilization patterns of soil microbial communities. The N+P fertilization at 15 g m-2 yr-1 may be used in increasing plant aboveground biomass and soil C accumulation under these meadows.

  9. Geophysical Modeling of the Dixie Meadows Geothermal Prospect: Dual Analysis of Gravity and Magnetic Data towards Identifying Structural Controls

    NASA Astrophysics Data System (ADS)

    Schwering, Paul C.

    The northern Great Basin has abundant geothermal systems. Studies have shown these systems are structurally controlled by extensional faults. The faults, and sometimes systems themselves, often have little or no surface expression and must therefore be characterized by geophysical methods. The Dixie Meadows geothermal prospect, located within the Humboldt Structural Zone in central Dixie Valley, Nevada, was investigated in this study in order to delineate basin and fault structure that likely control hydrothermal fluid flow in the subsurface. The study focused on dual interpretation and modeling of gravity and magnetic geophysical data, but was also supported by geological reconnaissance and assessment of surficial hydrothermal expressions. Results indicate a concealed piedmont fault zone separates a deep basin from a relatively shallow intra-basin adjacent to the rangefront. Geophysically delineated faults are located in the intra-basin and piedmont fault zones, and have little or no surface expressions. Rangefront, intra-basin, and piedmont faults are interpreted to be moderately- to steeply-dipping. Faults strike in multiple directions, revealing a network of interlinking and interacting faults. Interpreted structural, geophysical, and hydrothermal patterns along the intrabasin and rangefront demarcate a primary geothermal target area and two secondary targets. The primary target area is characterized by advanced argillic alteration at the surface and upflow indicated by two fumarole zones. Fault intersection appears to be the key structural pattern controlling upflow in the target areas, but fault splaying and step-over are also contributing factors. Integration of dual gravity and magnetic models with geological observations indicates three discrete phases of extension have occurred in Cenozoic time. The superposition of normal faults from these extensional phases appears to be a key component in generating the fault patterns that are controlling hydrothermal

  10. Carbohydrate storage in meadow plants and its depletion after disturbance: do roots and stem-derived organs differ in their roles?

    PubMed

    Janeček, Stěpán; Klimešová, Jitka

    2014-05-01

    Storage of carbohydrates in organs protected from disturbance is an important adaptation of plants in disturbed habitats. We carried out a field experiment involving 31 herbaceous plant species in two cultural meadows to find out whether roots or belowground stem-derived organs (stem bases, stem tubers and rhizomes) are the main storage organs, to study how reserves accumulate in individual organs in the long term (growing season) and to ascertain whether meadow abandonment affects the distribution of carbohydrate reserves in plants. We also conducted a 22-day pot experiment with four meadow plant species to determine how removal of roots and aboveground parts affects the use of carbohydrates stored in roots and stem-derived organs in the short term. From the long-term perspective of the field experiment, mowing had a positive effect on the concentration of carbohydrate reserves. From the short-term perspective of the pot experiment, however, the effect on concentration and pools of carbohydrates was negative. In the field experiment, carbohydrate concentrations before winter were generally higher than in mid-season, and more often higher in roots than in stem-derived organs. Roots and stem-derived organs of plants in the pot experiment were depleted similarly after both types of disturbance. Our results indicate a need for including both types of belowground plant organs in future studies of the carbon economy of plants from disturbed habitats.

  11. Effects of rodent-induced land degradation on ecosytem carbon fluxes in alpine meadow in the Qinghai-Tibet Plateau, China

    NASA Astrophysics Data System (ADS)

    Peng, F.; Quangang, Y.; Xue, X.; Guo, J.; Wang, T.

    2014-10-01

    Land degradation induced by rodent activities is extensively occurred in alpine meadow ecosystem in the Qinghai-Tibet Plateau that would affect the ecosystem carbon (C) balance. We conducted a field experiment with six levels of land degradation (D1-D6, degradation aggravates from D1 to D6) to investigate the effects of land degradation on ecosystem C fluxes. Soil respiration (Rs), net ecosystem exchange (NEE), ecosystem respiration (ER) and gross ecosystem production (GEP) were measured from June to September 2012. Soil respiration, ER, GEP and above-ground biomass (AGB) was significantly higher in slightly degraded (D3 and D6) than in severely degraded land (D1, D2, D4 and D5). Positive averages of NEE in the growing season indicate that alpine meadow ecosystem is a weak C sink during the growing season. Net ecosystem exchange had no significant difference among different degraded levels, but the average NEE in slightly degraded group was 33.6% higher than in severely degraded group. Soil respiration, ER and NEE were positively correlated with AGB whereas soil organic C, labile soil C, total nitrogen (N) and inorganic nitrogen were associated with root biomass (RB). Our results highlight the decline of vegetation C storage of alpine meadow ecosystem with increasing number of rodent holes and suggest the control of AGB on ecosystem C fluxes, and the control of RB on soil C and N with development of land degradation.

  12. Spatial Structure of Seagrass Suggests That Size-Dependent Plant Traits Have a Strong Influence on the Distribution and Maintenance of Tropical Multispecies Meadows

    PubMed Central

    Ooi, Jillian L. S.; Van Niel, Kimberly P.; Kendrick, Gary A.; Holmes, Karen W.

    2014-01-01

    Background Seagrass species in the tropics occur in multispecies meadows. How these meadows are maintained through species co-existence and what their ecological drivers may be has been an overarching question in seagrass biogeography. In this study, we quantify the spatial structure of four co-existing species and infer potential ecological processes from these structures. Methods and Results Species presence/absence data were collected using underwater towed and dropped video cameras in Pulau Tinggi, Malaysia. The geostatistical method, utilizing semivariograms, was used to describe the spatial structure of Halophila spp, Halodule uninervis, Syringodium isoetifolium and Cymodocea serrulata. Species had spatial patterns that were oriented in the along-shore and across-shore directions, nested with larger species in meadow interiors, and consisted of multiple structures that indicate the influence of 2–3 underlying processes. The Linear Model of Coregionalization (LMC) was used to estimate the amount of variance contributing to the presence of a species at specific spatial scales. These distances were <2.5 m (micro-scale), 2.5–50 m (fine-scale) and >50 m (broad-scale) in the along-shore; and <2.5 m (micro-scale), 2.5–140 m (fine-scale) and >140 m (broad-scale) in the across-shore. The LMC suggests that smaller species (Halophila spp and H. uninervis) were most influenced by broad-scale processes such as hydrodynamics and water depth whereas large, localised species (S. isoetifolium and C. serrulata) were more influenced by finer-scale processes such as sediment burial, seagrass colonization and growth, and physical disturbance. Conclusion In this study, we provide evidence that spatial structure is distinct even when species occur in well-mixed multispecies meadows, and we suggest that size-dependent plant traits have a strong influence on the distribution and maintenance of tropical marine plant communities. This study offers a contrast from previous spatial

  13. Temporal variation in mycorrhizal diversity and carbon and nitrogen stable isotope abundance in the wintergreen meadow orchid Anacamptis morio.

    PubMed

    Ercole, Enrico; Adamo, Martino; Rodda, Michele; Gebauer, Gerhard; Girlanda, Mariangela; Perotto, Silvia

    2015-02-01

    Many adult orchids, especially photoautotrophic species, associate with a diverse range of mycorrhizal fungi, but little is known about the temporal changes that might occur in the diversity and functioning of orchid mycorrhiza during vegetative and reproductive plant growth. Temporal variations in the spectrum of mycorrhizal fungi and in stable isotope natural abundance were investigated in adult plants of Anacamptis morio, a wintergreen meadow orchid. Anacamptis morio associated with mycorrhizal fungi belonging to Tulasnella, Ceratobasidium and a clade of Pezizaceae (Ascomycetes). When a complete growing season was investigated, multivariate analyses indicated significant differences in the mycorrhizal fungal community. Among fungi identified from manually isolated pelotons, Tulasnella was more common in autumn and winter, the pezizacean clade was very frequent in spring, and Ceratobasidium was more frequent in summer. By contrast, relatively small variations were found in carbon (C) and nitrogen (N) stable isotope natural abundance, A. morio samples showing similar (15)N enrichment and (13)C depletion at the different sampling times. These observations suggest that, irrespective of differences in the seasonal environmental conditions, the plant phenological stages and the associated fungi, the isotopic content in mycorrhizal A. morio remains fairly constant over time.

  14. Ecological data in Integrated Coastal Zone Management: case study of Posidonia oceanica meadows along the Corsican coastline (Mediterranean Sea).

    PubMed

    Pergent-Martini, Christine; Pasqualini, Vanina; Ferrat, Lila; Pergent, Gérard

    2006-12-01

    Integrated Coastal Zone Management (ICZM) contributes towards maximizing the benefits provided by the coastal zone and minimizing conflicts and the harmful effects of activities upon each other. The coastal zone includes highly productive and biologically diverse ecosystems, but ecological data (including structure and processes) seem to be neglected. The purpose of this article is to present a case study of Posidonia oceanica meadows (seagrass beds) along the Corsican coastline (Mediterranean Sea) in order to exemplify the usefulness of ecological data to Integrated Costal Management programs. We will try to determine how the use of organisms could be enhanced. These investigations show the undoubted success of the Corsican Posidonia oceanica protection program, with a detailed description of the ICZM that precisely presents each component (e.g., mapping, assessment of water quality, implementation of a system to aid decision-making concerning the installation of new aquaculture units). This experience on the Corsican coasts could be used as an example in order to transfer to other locations in the Mediterranean Sea and/or to other target species. PMID:17001505

  15. Diversity and distribution patterns of root-associated fungi on herbaceous plants in alpine meadows of southwestern China.

    PubMed

    Gao, Qian; Yang, Zhu L

    2016-01-01

    The diversity of root-associated fungi associated with four ectomycorrhizal herbaceous species, Kobresia capillifolia, Carex parva, Polygonum macrophyllum and Potentilla fallens, collected in three sites of alpine meadows in southwestern China, was estimated based on internal transcribed spacer (ITS) rDNA sequence analysis of root tips. Three hundred seventy-seven fungal sequences sorted to 154 operational taxonomical units (sequence similarity of ≥ 97% across the ITS) were obtained from the four plant species across all three sites. Similar taxa (in GenBank with ≥ 97% similarity) were not found in GenBank and/or UNITE for most of the OTUs. Ectomycorrhiz a made up 64% of the fungi operational taxonomic units (OTUs), endophytes constituted 4% and the other 33% were unidentified root-associated fungi. Fungal OTUs were represented by 57% basidiomycetes and 43% ascomycetes. Inocybe, Tomentella/Thelophora, Sebacina, Hebeloma, Pezizomycotina, Cenococcum geophilum complex, Cortinarius, Lactarius and Helotiales were OTU-rich fungal lineages. Across the sites and host species the root-associated fungal communities generally exhibited low host and site specificity but high host and sampling site preference. Collectively our study revealed noteworthy diversity and endemism of root-associated fungi of alpine plants in this global biodiversity hotspot.

  16. Changes in soil microbial community structure and function in an alpine dry meadow following spring snow melt.

    PubMed

    Lipson, D A; Schadt, C W; Schmidt, S K

    2002-04-01

    Previous work in an alpine dry meadow in the Front Range of the Rocky Mountains has shown that microbial biomass is high during winter and declines rapidly as snow melts in the spring, and that this decline is associated with changes in temperature regime and substrate availability. In this study we tested the hypothesis that the summer and winter microbial communities differ in function and composition. Shifts in species composition between pre- and post-snowmelt communities were detected using reciprocal hybridization of community DNA; DNA extracted from soils sampled at different times was significantly less homologous relative to spatial replicates sampled at the same time. Fungal/bacterial ratios, as measured by direct microscopic counts and by substrate-induced respiration experiments with specific inhibitors, were higher in winter soils. Specific activity of cellulase (absolute cellulase activity per unit microbial biomass C) was higher in the winter soils than in summer soils, while specific amylase activity was not different between winter and summer. Based on most-probable number measurements, the use of the phenolic compound vanillic acid was highest in the winter, while the use of the amino acid glycine was lowest in the winter. Winter and summer soil respiration responded differently to temperature; at 0 degrees C, winter soils respired at a higher proportion of the 22 degrees C rate than did summer soils. PMID:12037609

  17. Effects of short-term grazing exclusion on plant phenology and reproductive succession in a Tibetan alpine meadow.

    PubMed

    Zhu, Juntao; Zhang, Yangjian; Liu, Yaojie

    2016-01-01

    Grazing exclusion (GE) has been widely considered as an effective avenue for restoring degraded grasslands throughout the world. GE, via modifying abiotic and biotic environments, inevitably affects phenological development. A five-year manipulative experiment was conducted in a Tibetan alpine meadow to examine the effects of GE on phenological processes and reproductive success. The study indicated that GE strongly affected phenological development of alpine plant species. Specifically, the low-growing, shallow-rooted species (LSS), such as Kobresia pygmaea, are more sensitive to GE-caused changes on upper-soil moisture and light. GE advanced each phonological process of K. pygmaea, except in the case of the treatment of fencing for 5 years (F5), which postponed the reproductive stage and lowered the reproductive success of K. pygmaea. Increased soil moisture triggered by GE, especially in the upper soil, may stimulate growth of LSS. However, the thick litter layer under the F5 treatment can influence the photoperiod of LSS, resulting in suppression of its reproductive development. These findings indicate that plant traits associated with resource acquisition, such as rooting depth and plant height, mediate plant phenology and reproductive responses to grazing exclusion treatments. PMID:27301554

  18. Changes in soil microbial community structure and function in an alpine dry meadow following spring snow melt.

    PubMed

    Lipson, D A; Schadt, C W; Schmidt, S K

    2002-04-01

    Previous work in an alpine dry meadow in the Front Range of the Rocky Mountains has shown that microbial biomass is high during winter and declines rapidly as snow melts in the spring, and that this decline is associated with changes in temperature regime and substrate availability. In this study we tested the hypothesis that the summer and winter microbial communities differ in function and composition. Shifts in species composition between pre- and post-snowmelt communities were detected using reciprocal hybridization of community DNA; DNA extracted from soils sampled at different times was significantly less homologous relative to spatial replicates sampled at the same time. Fungal/bacterial ratios, as measured by direct microscopic counts and by substrate-induced respiration experiments with specific inhibitors, were higher in winter soils. Specific activity of cellulase (absolute cellulase activity per unit microbial biomass C) was higher in the winter soils than in summer soils, while specific amylase activity was not different between winter and summer. Based on most-probable number measurements, the use of the phenolic compound vanillic acid was highest in the winter, while the use of the amino acid glycine was lowest in the winter. Winter and summer soil respiration responded differently to temperature; at 0 degrees C, winter soils respired at a higher proportion of the 22 degrees C rate than did summer soils.

  19. Relationship between Reproductive Allocation and Relative Abundance among 32 Species of a Tibetan Alpine Meadow: Effects of Fertilization and Grazing

    PubMed Central

    Niu, Kechang; Schmid, Bernhard; Choler, Philippe; Du, Guozhen

    2012-01-01

    Background Understanding the relationship between species traits and species abundance is an important goal in ecology and biodiversity science. Although theoretical studies predict that traits related to performance (e.g. reproductive allocation) are most directly linked to species abundance within a community, empirical investigations have rarely been done. It also remains unclear how environmental factors such as grazing or fertilizer application affect the predicted relationship. Methodology We conducted a 3-year field experiment in a Tibetan alpine meadow to assess the relationship between plant reproductive allocation (RA) and species relative abundance (SRA) on control, grazed and fertilized plots. Overall, the studied plant community contained 32 common species. Principal Findings At the treatment level, (i) RA was negatively correlated with SRA on control plots and during the first year on fertilized plots. (ii) No negative RA–SRA correlations were observed on grazed plots and during the second and third year on fertilized plots. (iii) Seed size was positively correlated with SRA on control plots. At the plot level, the correlation between SRA and RA were not affected by treatment, year or species composition. Conclusions/Significance Our study shows that the performance-related trait RA can negatively affect SRA within communities, which is possibly due to the tradeoffs between clonal growth (for space occupancy) and sexual reproduction. We propose that if different species occupy different positions along these tradeoffs it will contribute to biodiversity maintenance in local communities or even at lager scale. PMID:22536385

  20. Direct and indirect influences of 8 yr of nitrogen and phosphorus fertilization on Glomeromycota in an alpine meadow ecosystem.

    PubMed

    Liu, Yongjun; Shi, Guoxi; Mao, Lin; Cheng, Gang; Jiang, Shengjing; Ma, Xiaojun; An, Lizhe; Du, Guozhen; Collins Johnson, Nancy; Feng, Huyuan

    2012-04-01

    We measured the influences of soil fertility and plant community composition on Glomeromycota, and tested the prediction of the functional equilibrium hypothesis that increased availability of soil resources will reduce the abundance of arbuscular mycorrhizal (AM) fungi. Communities of plants and AM fungi were measured in mixed roots and in Elymus nutans roots across an experimental fertilization gradient in an alpine meadow on the Tibetan Plateau. As predicted, fertilization reduced the abundance of Glomeromycota as well as the species richness of plants and AM fungi. The response of the glomeromycotan community was strongly linked to the plant community shift towards dominance by Elymus nutans. A reduction in the extraradical hyphae of AM fungi was associated with both the changes in soil factors and shifts in the plant community composition that were caused by fertilization. Our findings highlight the importance of soil fertility in regulating both plant and glomeromycotan communities, and emphasize that high fertilizer inputs can reduce the biodiversity of plants and AM fungi, and influence the sustainability of ecosystems.

  1. Availability of nest cavity trees for wood ducks (Aix sponsa) at Sunkhaze Meadows National Wildlife Refuge, Maine

    USGS Publications Warehouse

    Clugston, D.A.

    1999-01-01

    The availability of natural cavities for cavitynesting waterfowl, especially wood ducks (Aix sponsa), was unknown ferating forest of Sunkhaze Meadows National Wildlife Refuge, ME. An assessment of cavity availability was needed to determine if the existing nesting box program should be increased. During November to March, 199697 and 199798, I sampled 56 onehalf ha random plots, stratified into 5 types (upland hardwood, upland conifer, upland mixwood, wetland conifer, and wetland hardwood) to assess availability of trees with cavities. The predominant tree species with cavities were red maple (Acer rubrum; 39%) and aspen (Populus sp.; 31%); 72% of all trees with cavities were alive. Density ees/plot averaged from 1.0 +0.4 (x +SE) in wetland softwoods to 1.9 +0.4 in upland hardwoods. This low density of potential cavity trees and the small mean dbh (39.4 +1.6 cm) indicate a young forest with few suitable cavities. Forested areas, especially hardwoods near canopy openings, need to be allowed to mature to increase the number and quality of future cavities. An expanded nest box program seems justified.

  2. Composition, abundance, biomass, and production of macrofauna in a New England estuary: comparisons among eelgrass meadows and other nursery habitats

    USGS Publications Warehouse

    Heck, K.L.; Able, K.W.; Roman, C.T.; Fahay, M.P.

    1995-01-01

    Quantitative suction sampling was used to characterize and compare the species composition, abundance, biomass, and secondary production of macrofauna inhabiting intertidal mudflat and sandflat, eelgrass meadow, and saltmarshpool habitats in the Nauset Marsh complex, Cape Cod, Massachusetts (USA). Species richness and abundance were often greatest in eelgrass habitat, as was macroinvertebrate biomass and production. Most striking was the five to fifteen times greater rate of annual macrofaunal production in eelgrass habitat than elsewhere, with values ranging from approximately 23139 g AFDW m super(2) yr super(1). The marsh pool containing widgeon grass (Ruppia maritima) supported surprisingly low numbers of macroinvertebrates, probably due to stressfully low dissolved oxygen levels at night during the summer. Two species of macroinvertebrates, blue mussels (Mytilus edulis) and to a lesser extent bay scallops (Argopecten irradians), used eelgrass as 'nursery habitat.' Calculations showed that macroinvertebrate production is proportionally much greater than the amount of primary production attributable to eelgrass in the Nauset Marsh system, and that dramatic changes at all trophic levels could be expected if large changes in seagrass abundance should occur. This work further underscores the extraordinarily large impact that seagrass can have on both the structure and function of estuarine ecosystems.

  3. The influence of canopy structure and tidal level on fish assemblages in tropical Southeast Asian seagrass meadows

    NASA Astrophysics Data System (ADS)

    Pogoreutz, Claudia; Kneer, Dominik; Litaay, Magdalena; Asmus, Harald; Ahnelt, Harald

    2012-07-01

    Seagrass meadows support abundant and diverse fish assemblages, but there are very few studies on the relation between seagrass beds with distinctly different plant canopies and their associated fish fauna. In the present study, fish assemblages were investigated by underwater visual census at intertidal and subtidal sites with varying seagrass species composition, shoot density, biomass, and leaf area index (LAI) on two small coral islands in the Spermonde Archipelago, Indonesia. We investigated (1) whether fish assemblages in distinctly different seagrass beds differ regarding community parameters, and (2) whether seagrass parameters affect fish abundances. Overall, more than 120 fish taxa were found. Bray-Curtis cluster analysis and non-Metric Multidimensional Scaling ordination (nMDS) showed site-specific similarities for fish assemblage structure with a distinct separation into subtidal and intertidal sites. Species accumulation curves for gamma diversity, single study sites, and the two most diverse fish families (Labridae, Pomacentridae), suggesting that species numbers are likely to increase with diel sampling. Total fish abundance and abundance for six out of the nine most common species varied distinctly among the study sites. The study indicates that seagrass beds with differing canopy parameters support distinct fish assemblages that differ with respect to species richness, dominant species, and the abundance of total and most common fish species. These differences are likely due to different canopy structures and water depth.

  4. Long-term evolution (1988-2008) of Zostera spp. meadows in Arcachon Bay (Bay of Biscay)

    NASA Astrophysics Data System (ADS)

    Martin, Plus; Sébastien, Dalloyau; Gilles, Trut; Isabelle, Auby; de Montaudouin, Xavier; Emery, Éric; Claire, Noël; Christophe, Viala

    2010-04-01

    The spatial variability of seagrass meadows in Arcachon Bay, was studied between 1988 and 2008 using a combination of mapping techniques based on aerial photographs for intertidal dwarf-grass ( Zostera noltii) beds and acoustic sonar for permanently submerged eelgrass ( Zostera marina) populations. The results show a severe decline over the period for both species, as well as an acceleration of the decline since 2005 for Z. noltii. The total surface regression over the studied period is estimated to be 22.8 km 2 for Z. noltii and 2.7 km 2 for Z. marina, which represent declines of 33 and 74% respectively. Environmental data time series spanning the same period were investigated in order to seek the causes for such a decline. The calculated inter-annual trends for temperature, salinity, nitrate plus nitrite, ammonia, suspended sediment and chlorophyll a did not identify any clear environmental change capable of explaining the observed seagrass regression. For instance, no evident sign of eutrophication was observed over the study period. On the other hand, we suggest that the observed variations of ammonia in the inner part of the lagoon are a symptom of the seagrasses' disappearance and thus, a first sign indicating a change of the Arcachon Bay ecosystem towards more instability and vulnerability. Several hypotheses to explain the observed seagrass decay are proposed.

  5. Effects of short-term grazing exclusion on plant phenology and reproductive succession in a Tibetan alpine meadow

    PubMed Central

    Zhu, Juntao; Zhang, Yangjian; Liu, Yaojie

    2016-01-01

    Grazing exclusion (GE) has been widely considered as an effective avenue for restoring degraded grasslands throughout the world. GE, via modifying abiotic and biotic environments, inevitably affects phenological development. A five-year manipulative experiment was conducted in a Tibetan alpine meadow to examine the effects of GE on phenological processes and reproductive success. The study indicated that GE strongly affected phenological development of alpine plant species. Specifically, the low-growing, shallow-rooted species (LSS), such as Kobresia pygmaea, are more sensitive to GE-caused changes on upper-soil moisture and light. GE advanced each phonological process of K. pygmaea, except in the case of the treatment of fencing for 5 years (F5), which postponed the reproductive stage and lowered the reproductive success of K. pygmaea. Increased soil moisture triggered by GE, especially in the upper soil, may stimulate growth of LSS. However, the thick litter layer under the F5 treatment can influence the photoperiod of LSS, resulting in suppression of its reproductive development. These findings indicate that plant traits associated with resource acquisition, such as rooting depth and plant height, mediate plant phenology and reproductive responses to grazing exclusion treatments. PMID:27301554

  6. Mobility and bio-availability of heavy metals in anthropogenically contaminated alluvial (deluvial) meadow soils (EUTRIC FLUVISOLS)

    NASA Astrophysics Data System (ADS)

    Dinev, Nikolai; Hristova, Mariana; Tzolova, Venera

    2015-04-01

    The total content of heavy metals is not sufficient to assess the pollution and the risk for environment as it does not provide information for the type and solubility of heavy metals' compounds in soils. The purpose was to study and determine the mobility of heavy metals in anthropogenically contaminated alluvial (delluvial) meadow soils spread around the non-ferrous plant near the town of Asenovgrad in view of risk assessment for environment pollution. Soil samples from monitoring network (1x1 km) was used. The sequential extraction procedure described by Zein and Brummer (1989) was applied. Results showed that the easily mobilizable cadmium compounds predominate in both contaminated and not contaminated soils. The stable form of copper (associated with silicate minerals, carbonates or amorphous and crystalline oxide compounds) predominates only in non polluted soils and reviles the risk of the environment contamination. Lead spreads and accumulates as highly soluble (mobile) compounds and between 72.3 and 99.6 percent of the total lead is bioavailable in soils. The procedure is very suitable for studying the mobility of technogenic lead and copper in alluvial soils with neutral medium reaction and in particular at the high levels of cadmium contamination. In soils with alkaline reaction - polluted and unpolluted the error of analysis increases for all studied elements.

  7. Niche and Neutral Processes Together Determine Diversity Loss in Response to Fertilization in an Alpine Meadow Community

    PubMed Central

    Li, Wei; Cheng, Ji-Min; Yu, Kai-Liang; Epstein, Howard E.; Du, Guo-Zhen

    2015-01-01

    Fertilization via nutrient deposition and agricultural inputs is one of the most important factors driving decreases in plant diversity. However, we still do not fully understand which processes (niche process or neutral process) are more important in leading to decreases in plant diversity caused by fertilization. A hypothesis-based approach was used to test the relative importance of niche versus neutral processes along a fertilization gradient in an alpine meadow community on the eastern Tibetan plateau, China. Niche overlap values were calculated for species biomass, and the null model was used to generate the values of niche overlap expected at random. A linear regression modeling was used to evaluate the relationship between functional traits (specific leaf area, leaf dry matter content, and leaf total nitrogen concentration) and species relative abundance. Our results demonstrated that observed niche overlap for species biomass was significantly higher than expected at lower fertilization gradients. Moreover, we also found a significantly negative correlation between species relative abundance and specific leaf area and leaf dry matter content, but a significantly positive correlation between relative abundance and leaf nitrogen concentration at lower fertilization gradients. However, these relationships were not significant at higher fertilization gradients. We concluded that community assembly is dynamic progression along the environmental gradients, and niche and neutral processes may together determine species diversity loss in response to fertilization. PMID:26280919

  8. Diversity and distribution patterns of root-associated fungi on herbaceous plants in alpine meadows of southwestern China.

    PubMed

    Gao, Qian; Yang, Zhu L

    2016-01-01

    The diversity of root-associated fungi associated with four ectomycorrhizal herbaceous species, Kobresia capillifolia, Carex parva, Polygonum macrophyllum and Potentilla fallens, collected in three sites of alpine meadows in southwestern China, was estimated based on internal transcribed spacer (ITS) rDNA sequence analysis of root tips. Three hundred seventy-seven fungal sequences sorted to 154 operational taxonomical units (sequence similarity of ≥ 97% across the ITS) were obtained from the four plant species across all three sites. Similar taxa (in GenBank with ≥ 97% similarity) were not found in GenBank and/or UNITE for most of the OTUs. Ectomycorrhiz a made up 64% of the fungi operational taxonomic units (OTUs), endophytes constituted 4% and the other 33% were unidentified root-associated fungi. Fungal OTUs were represented by 57% basidiomycetes and 43% ascomycetes. Inocybe, Tomentella/Thelophora, Sebacina, Hebeloma, Pezizomycotina, Cenococcum geophilum complex, Cortinarius, Lactarius and Helotiales were OTU-rich fungal lineages. Across the sites and host species the root-associated fungal communities generally exhibited low host and site specificity but high host and sampling site preference. Collectively our study revealed noteworthy diversity and endemism of root-associated fungi of alpine plants in this global biodiversity hotspot. PMID:26740542

  9. Grazing exclusion reduced soil respiration but increased its temperature sensitivity in a Meadow Grassland on the Tibetan Plateau.

    PubMed

    Chen, Ji; Zhou, Xuhui; Wang, Junfeng; Hruska, Tracy; Shi, Weiyu; Cao, Junji; Zhang, Baocheng; Xu, Gexi; Chen, Yizhao; Luo, Yiqi

    2016-02-01

    Understanding anthropogenic influences on soil respiration (R s) is critical for accurate predictions of soil carbon fluxes, but it is not known how R s responds to grazing exclusion (GE). Here, we conducted a manipulative experiment in a meadow grassland on the Tibetan Plateau to investigate the effects of GE on R s. The exclusion of livestock significantly increased soil moisture and above-ground biomass, but it decreased soil temperature, microbial biomass carbon (MBC), and R s. Regression analysis indicated that the effects of GE on R s were mainly due to changes in soil temperature, soil moisture, and MBC. Compared with the grazed blocks, GE significantly decreased soil carbon release by 23.6% over the growing season and 21.4% annually, but it increased the temperature sensitivity (Q10) of R s by 6.5% and 14.2% for the growing season and annually respectively. Therefore, GE may reduce the release of soil carbon from the Tibetan Plateau, but under future climate warming scenarios, the increases in Q10 induced by GE could lead to increased carbon emissions. PMID:26865957

  10. Using sensitive montane amphibian species as indicators of hydroclimatic change in meadow ecosystems of the Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Peek, R.; Viers, J.; Yarnell, S. M.

    2012-12-01

    Climate change can affect sensitive species and ecosystems in many ways, yet sparse data and the inability to apply various climate models at functional spatial scales often prevents relevant research from being utilized in conservation management plans. Climate change has been linked to declines and disturbances in a multitude of species and habitats, and in California, one of the greatest climatic concerns is the predicted reduction in mountain snowpack and associated snowmelt. These decreases in natural storage of water as snow in mountain regions can affect the timing and variability of critical snowmelt runoff periods—important seasonal signals that species in montane ecosystems have evolved life history strategies around—leading to greater intra-annual variability and diminished summer and fall stream flows. Although many species distribution models exist, few provide ways to integrate continually updated and revised Global Climate Models (GCMs), hydrologic data unique to a watershed, and ecological responses that can be incorporated into conservation strategies. This study documents a novel and applicable method of combining boosted regression tree (BRT) modeling and species distributions with hydroclimatic data as a potential management tool for conservation. Boosted regression trees are suitable for ecological distribution modeling because they can reduce both bias and variance, as well as handle sharp discontinuities common in sparsely sampled species or large study areas. This approach was used to quantify the effects of hydroclimatic changes on the distribution of key riparian-associated amphibian species in montane meadow habitats in the Sierra Nevada at the sub-watershed level. Based on modeling using current species range maps in conjunction with three climate scenarios (near, mid, and far), extreme range contractions were observed for all sensitive species (southern long-toed salamander, mountain yellow-legged frog, Yosemite toad) by the year

  11. Hydrological and vegetational response to the Younger Dryas climatic oscillations: a high resolution case study from Quoyloo Meadow, Orkney, Scotland

    NASA Astrophysics Data System (ADS)

    Maas, David; Abrook, Ashley; Timms, Rhys; Matthews, Ian; Palmer, Adrian; Milner, Alice; Candy, Ian; Sachse, Dirk

    2016-04-01

    The Younger Dryas (Loch Lomond) Stadial is a well defined period of cold climate that in North West Europe punctuated the climatic amelioration during the Last Glacial - Interglacial Transition (LGIT ca. 16-8 ka). A palaeolake record from Quoyloo Meadow, Orkney Islands (N59.067, E-3.309) has been analysed for pollen and stable isotopes on biomarker lipids. n-Alkanes from terrestrial and aquatic sources are present throughout the core. The average chain length (ACL) is relatively low during the interstadial (~28.0) and shows a distinct increase during the Younger Dryas (to 29.0 +), attributed to an increase in grasses and drought resistant shrubs (e.g. Artemisia, Castañeda et al., 2009, Bunting, 1994). At the beginning of the Holocene, the ACL rapidly drops to 28.3 and from thereon gently increases again to ~29.0. There is a continued odd-over-even n-alkane predominance, although even n-alkanes are present in greater quantities in the interstadial, indicating an increasing terrestrial contribution in the Holocene. Ongoing deuterium isotope measurements of the n-alkanes will give independent evidence for palaeohydrological changes and can be compared to the other proxy evidence within the same core. Using a combination of nC29 and nC23 (terrestrial and aquatic end-members, respectively), a change in relative humidity (rH) can be qualified. This is based on the idea that terrestrial vegetation is affected by evapotranspiration processes, whereas aquatic vegetation is not (Rach et al., 2014). This data is supported by a high resolution palynological study; the contiguously sampled record demonstrates ecosystem/environmental responses to millennial-scale climatic change and allows for the possible detection of vegetation shifts at the sub-millennial scale. Vegetation aside, the pollen data can further aid in the interpretation of the recorded n-alkanes and isotopic analyses. This data is placed within a chronological framework derived from a high resolution crypto- and

  12. Microbial diversity in alpine tundra wet meadow soil: novel Chloroflexi from a cold, water-saturated environment.

    PubMed

    Costello, Elizabeth K; Schmidt, Steven K

    2006-08-01

    Cold, water-saturated soils play important biogeochemical roles, yet almost nothing is known about the identity and habitat of microbes active under such conditions. We investigated the year-round microenvironment of an alpine tundra wet meadow soil in the Colorado Rocky Mountains, focusing on the biogeochemistry and microbial diversity of spring snowmelt--a dynamic time for alpine ecosystems. In situ measurements revealed spring and autumn periods of long-term temperature stability near 0 degrees C, and that deeper soil (30 cm) was more stable than surface soil, with more moderate summers and winters, and longer isothermal phases. The soil was saturated and water availability was limited by freezing rather than drying. Analyses of bioavailable redox species showed a shift from Mn reduction to net Fe reduction at 2-3 cm depth, elevated SO4(2-) and decreased soluble Zn at spring snowmelt. Terminal restriction fragment length polymorphism profiles detected a correlated shift in bacterial community composition at the surface to subsurface transition. Bacterial and archaeal small-subunit rRNA genes were amplified from saturated spring soil DNA pooled along a depth profile. The most remarkable feature of these subsurface-biased libraries was the high relative abundance of novel, uncultivated Chloroflexi-related sequences comprising the third largest bacterial division sampled, and representing seven new Chloroflexi subdivisions, thereby dramatically expanding the known diversity of this bacterial division. We suggest that these novel Chloroflexi are active at near -0 degrees C temperatures, under likely anoxic conditions, and utilize geochemical inputs such as sulfide from upslope weathering. PMID:16872409

  13. Resolving the spatial variability of sediment geochemistry within a seagrass (Zostera marina) meadow in the coastal bays of Virginia

    NASA Astrophysics Data System (ADS)

    Egge, N. E.; Macko, S. A.; O'connell, M. T.

    2013-12-01

    The environmental degradation of the areas of coastal Chesapeake Bay has been linked with explosive urbanization associated with human population growth and dramatic increases in agricultural activities. Possible impacts of these have been associated with diminishing seagrass (Zostera marina) coverage. Numerous efforts have been made to restore seagrass meadows. As a result of large-scale, seed-based restorations in South Bay (2001) and Hog Island Bay (2007), Z. marina has come to dominate portions of these bays. In this study, a spatially random sampling pattern was used to assess the frequency at which a variety of geochemical characteristics within the South Bay study area were correlated. Initial sampling is within a hectare window; cores were collected in a plot of samples simulated as a homogeneous Poisson distribution. Stable isotope and geochemical proxies are used to suggest the source of organic material within the coastal bays. Carbon and nitrogen isotope analyses were conducted on freeze-dried and acidified samples; sediments dominated by seagrass contain organic matter more enriched in 13C relative to autochthonous algal and planktonic marine materials. These data have been used to establish the spatial autocorrelation of sediment geochemistry for the surface, as well as deeper sediments. After the initial geostatistical parameter estimation, a random systematic grid pattern has been applied that satisfies assumptions of non-preferential design by randomly locating sampling points within the grid space. The systematic grid thus allows for the representation of the plot as a whole, as well as evaluation of spatial trends within the data. Fitting of geostatistical models will be presented using both conventional and Bayesian Kriging models. Results from this study may be able to be used to evaluate potential for carbon sequestration in these system as well as guide future restoration projects.

  14. Ground-water hydrology of the Mormon Island Crane Meadows Wildlife Area near Grand Island, Hall County, Nebraska

    USGS Publications Warehouse

    Hurr, T.R.

    1981-01-01

    The Platte River in south-central Nebraska flows generally eastward in a broad, flat valley. The river banks and many areas adjacent to the river support thick stands of cottonwood and willow trees. Brush, grass, pasture land, and cultivated fields occupy most of the remaining area. This is the habitat for many types of wildlife that live in the area or stop over in the area during annual migrations. Both sandhill cranes and whooping cranes are part of the annual migration. There is concern that water-management changes, such as surface-water diversions or ground-water withdrawals for irrigation, may alter the hydrologic environment of the wetland areas and be harmful to the wildlife habitat. In order to determine what affect changes in water management might have on ground-water levels in the wetland areas, detailed data were collected from Crane Meadows Wildlife Area, which is on an island in the Platte River near Grand Island, Nebr. Ground-water levels beneath the island respond to changes in river stage, to recharge from snowmelt and precipitation, and to evapotranspiration by riparian vegetation and from areas where the water table is close to the land surface. The data show that ground-water levels respond rapidly to changes in river stage--usually within 24 hours for distances up to 2,500 feet from the edge of the river. Thus changes in river stage due to changes in surface-water diversions will not have a long-term effect on ground-water levels. Changes in ground-water withdrawals will have the double effect of changing ground-water levels due to changes in drawdown and due to changes in river stage caused by the effects of pumping on river flow. These effects will develop slowly and be long lasting. (USGS)

  15. Interactive effects of winter weather variation and nitrogen deposition on alpine moist meadow ecosystem processes in the Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Churchill, A. C.

    2015-12-01

    Alpine climate change in the Rocky Mountains has been linked to changes in precipitation patterns between summer and winter periods, and in total amounts of accumulation over the year. Annual variation in alpine snowpack can have important effects on concentrations and amounts of nitrogen (N) deposition entering the alpine from the atmosphere, as between one third to one half of N deposition occurs in association with precipitation, and high elevations primarily receive precipitation in the form of winter snow. Variation in snowpack further affects the amount and timing of water available to vegetation during the growing season, which can have large implications for alpine ecosystem responses in association with N deposition. To examine the potential interactive effects of variation in winter weather and N deposition, we established five sites along an ambient gradient of N deposition in the Rocky Mountains and collected measurements of N cycling between 2012 and 2014. This time frame included a year with low snow pack (2012), a year with average snow pack (2013), and a year with high snow pack (2014) among sites in the study, and allowed for us to examine candidate dynamic climatic drivers that may create variation in ecosystem processes associated with N. We found that soil water nitrate concentrations following snow melt were highly different for 4 sites along the N deposition gradient between 2013 and 2014. Growing season resin extractable N, however, was unaffected by inter-annual changes in winter precipitation. One possible explanation for no change in resin N may be associated with high inter-annual variation in plant community composition. There were significant differences in the species composition between 2012 and 2013, as well as shifts in the concentrations of N found in dominant plant species tissue. Our results suggest that plants will be important controls on biogeochemical responses of alpine moist meadows under variation in winter precipitation.

  16. Effects of grazing on ecosystem CO₂ exchange in a meadow grassland on the Tibetan Plateau during the growing season.

    PubMed

    Chen, Ji; Shi, Weiyu; Cao, Junji

    2015-02-01

    Effects of human activity on ecosystem carbon fluxes (e.g., net ecosystem exchange (NEE), ecosystem respiration (R(eco)), and gross ecosystem exchange (GEE)) are crucial for projecting future uptake of CO2 in terrestrial ecosystems. However, how ecosystem that carbon fluxes respond to grazing exclusion is still under debate. In this study, a field experiment was conducted to study the effects of grazing exclusion on R(eco), NEE, and GEE with three treatments (free-range grazing (FG) and grazing exclusion for 3 and 5 years (GE3 and GE5, respectively)) in a meadow grassland on the Tibetan Plateau. Our results show that grazing exclusion significantly increased NEE by 47.37 and 15.84%, and R eco by 33.14 and 4.29% under GE3 and GE5 plots, respectively, although carbon sinks occurred in all plots during the growing season, with values of 192.11, 283.12, and 222.54 g C m(-2) for FG, GE3, and GE5, respectively. Interestingly, grazing exclusion increased temperature sensitivity (Q10) of R eco with larger increases at the beginning and end of growing season (i.e., May and October, respectively). Soil temperature and soil moisture were key factors on controlling the diurnal and seasonal variations of R(eco), NEE, and GEE, with soil temperature having a stronger influence. Therefore, the combined effects of grazing and temperature suggest that grazing should be taken into consideration in assessing global warming effects on grassland ecosystem CO2 exchange.

  17. BPA-Solicited Technical Review of "Echo Meadows Project Winter Artificial Recharge: Final Report for 2001 Baseline", Technical Report 2004.

    SciTech Connect

    Morgan, David

    2004-02-01

    The purpose of this report was to provide, at BPA's request, a technical review of interim products received for Project 2001-015-00 under contract 6925. BPA sometimes solicits technical reviews for Fish and Wildlife products or issues where outside expertise is required. External review of complex project deliverables assures BPA as a funding agency that the contractor is continuing with scientifically-credible experimental techniques envisioned in the original proposal. If the project's methodology proves feasible, there could be potential applications beyond the project area to similar situations in the Columbia Basin. The Experiment involves artificial flooding during high flow periods and a determination of the portion of the return flows that end up in the Umatilla River during low flow months and within acceptable water quality parameters (e.g., low temperature, few contaminants). Flooding could be a critical water source for aquatic organisms at times of the year when flows in the lower reaches of the Umatilla River are low and water is warmer than would be desired. The experiment was proposed to test whether 'this process, recharges the shallow aquifers of the old flood plain, for natural filtration through the alluvial soils as it returns to the Umatilla River, cleaner and cooler (about 50 degree Fahrenheit) five to six month later (about July and August) substantially cooling the river and [making it] more beneficial to anadromous [fish]'. A substantial amount of preliminary data had been collected and preliminary results were submitted in an interim report 'Echo Meadows Project Winter Artificial Recharge: Final Report for 2001 Baseline (December 2002)'. A substantial amount of addition funding was provided for the last cycle of flooding (Phases II) and final analyses of the full compliment of data collected over the life of the contract (Phase III). Third party scientific review may assist the contractor in producing a higher quality Final Report with

  18. Microbial diversity in alpine tundra wet meadow soil: novel Chloroflexi from a cold, water-saturated environment.

    PubMed

    Costello, Elizabeth K; Schmidt, Steven K

    2006-08-01

    Cold, water-saturated soils play important biogeochemical roles, yet almost nothing is known about the identity and habitat of microbes active under such conditions. We investigated the year-round microenvironment of an alpine tundra wet meadow soil in the Colorado Rocky Mountains, focusing on the biogeochemistry and microbial diversity of spring snowmelt--a dynamic time for alpine ecosystems. In situ measurements revealed spring and autumn periods of long-term temperature stability near 0 degrees C, and that deeper soil (30 cm) was more stable than surface soil, with more moderate summers and winters, and longer isothermal phases. The soil was saturated and water availability was limited by freezing rather than drying. Analyses of bioavailable redox species showed a shift from Mn reduction to net Fe reduction at 2-3 cm depth, elevated SO4(2-) and decreased soluble Zn at spring snowmelt. Terminal restriction fragment length polymorphism profiles detected a correlated shift in bacterial community composition at the surface to subsurface transition. Bacterial and archaeal small-subunit rRNA genes were amplified from saturated spring soil DNA pooled along a depth profile. The most remarkable feature of these subsurface-biased libraries was the high relative abundance of novel, uncultivated Chloroflexi-related sequences comprising the third largest bacterial division sampled, and representing seven new Chloroflexi subdivisions, thereby dramatically expanding the known diversity of this bacterial division. We suggest that these novel Chloroflexi are active at near -0 degrees C temperatures, under likely anoxic conditions, and utilize geochemical inputs such as sulfide from upslope weathering.

  19. Variation in phenology of hibernation and reproduction in the endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus)

    PubMed Central

    2015-01-01

    Hibernation is a key life history feature that can impact many other crucial aspects of a species’ biology, such as its survival and reproduction. I examined the timing of hibernation and reproduction in the federally endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus), which occurs across a broad range of latitudes and elevations in the American Southwest. Data from museum specimens and field studies supported predictions for later emergence and shorter active intervals in montane populations relative to lower elevation valley populations. A low-elevation population located at Bosque del Apache National Wildlife Refuge (BANWR) in the Rio Grande valley was most similar to other subspecies of Z. hudsonius: the first emergence date was in mid-May and there was an active interval of 162 days. In montane populations of Z. h. luteus, the date of first emergence was delayed until mid-June and the active interval was reduced to ca 124–135 days, similar to some populations of the western jumping mouse (Z. princeps). Last date of immergence into hibernation occurred at about the same time in all populations (mid to late October). In montane populations pregnant females are known from July to late August and evidence suggests that they have a single litter per year. At BANWR two peaks in reproduction were expected based on similarity of active season to Z. h. preblei. However, only one peak was clearly evident, possibly due to later first reproduction and possible torpor during late summer. At BANWR pregnant females are known from June and July. Due to the short activity season and geographic variation in phenology of key life history events of Z. h. luteus, recommendations are made for the appropriate timing for surveys for this endangered species. PMID:26290794

  20. Effects of grazing on ecosystem CO₂ exchange in a meadow grassland on the Tibetan Plateau during the growing season.

    PubMed

    Chen, Ji; Shi, Weiyu; Cao, Junji

    2015-02-01

    Effects of human activity on ecosystem carbon fluxes (e.g., net ecosystem exchange (NEE), ecosystem respiration (R(eco)), and gross ecosystem exchange (GEE)) are crucial for projecting future uptake of CO2 in terrestrial ecosystems. However, how ecosystem that carbon fluxes respond to grazing exclusion is still under debate. In this study, a field experiment was conducted to study the effects of grazing exclusion on R(eco), NEE, and GEE with three treatments (free-range grazing (FG) and grazing exclusion for 3 and 5 years (GE3 and GE5, respectively)) in a meadow grassland on the Tibetan Plateau. Our results show that grazing exclusion significantly increased NEE by 47.37 and 15.84%, and R eco by 33.14 and 4.29% under GE3 and GE5 plots, respectively, although carbon sinks occurred in all plots during the growing season, with values of 192.11, 283.12, and 222.54 g C m(-2) for FG, GE3, and GE5, respectively. Interestingly, grazing exclusion increased temperature sensitivity (Q10) of R eco with larger increases at the beginning and end of growing season (i.e., May and October, respectively). Soil temperature and soil moisture were key factors on controlling the diurnal and seasonal variations of R(eco), NEE, and GEE, with soil temperature having a stronger influence. Therefore, the combined effects of grazing and temperature suggest that grazing should be taken into consideration in assessing global warming effects on grassland ecosystem CO2 exchange. PMID:25355630

  1. Variation in phenology of hibernation and reproduction in the endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus).

    PubMed

    Frey, Jennifer K

    2015-01-01

    Hibernation is a key life history feature that can impact many other crucial aspects of a species' biology, such as its survival and reproduction. I examined the timing of hibernation and reproduction in the federally endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus), which occurs across a broad range of latitudes and elevations in the American Southwest. Data from museum specimens and field studies supported predictions for later emergence and shorter active intervals in montane populations relative to lower elevation valley populations. A low-elevation population located at Bosque del Apache National Wildlife Refuge (BANWR) in the Rio Grande valley was most similar to other subspecies of Z. hudsonius: the first emergence date was in mid-May and there was an active interval of 162 days. In montane populations of Z. h. luteus, the date of first emergence was delayed until mid-June and the active interval was reduced to ca 124-135 days, similar to some populations of the western jumping mouse (Z. princeps). Last date of immergence into hibernation occurred at about the same time in all populations (mid to late October). In montane populations pregnant females are known from July to late August and evidence suggests that they have a single litter per year. At BANWR two peaks in reproduction were expected based on similarity of active season to Z. h. preblei. However, only one peak was clearly evident, possibly due to later first reproduction and possible torpor during late summer. At BANWR pregnant females are known from June and July. Due to the short activity season and geographic variation in phenology of key life history events of Z. h. luteus, recommendations are made for the appropriate timing for surveys for this endangered species.

  2. Long-term records of trace metal content of western Mediterranean seagrass (Posidonia oceanica) meadows: Natural and anthropogenic contributions

    NASA Astrophysics Data System (ADS)

    Tovar-SáNchez, Antonio; Serón, Juan; Marbã, Núria; Arrieta, Jesús M.; Duarte, Carlos M.

    2010-06-01

    We discuss Al, Ag, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn contents in seagrass Posidonia oceanica rhizomes from the Balearic Archipelago for the last 3 decades. Time series of metal concentration in P. oceanica were measured by dating rhizomes using retrospective procedures. The highest concentrations of Al (174.73 μg g-1), Cd (3.56 μg g-1), Cr (1.34 μg g-1), Cu (32.15 μg g-1), Pb (8.51 μg g-1), and Zn (107.14 μg g-1) were measured in meadows located around the largest and most densely populated island (Mallorca Island). There was a general tendency for Ag concentration to decrease with time (up to 80% from 1990 to 2005 in sample from Mallorca Island), which could be attributed to a reduction of the anthropogenic sources. Nickel and Zn concentrations were the unique elements that showed a consistent temporal trend in all samples, increasing their concentrations since year 1996 at all studied stations; this trend matched with the time series of UV-absorbing aerosols particles in the air (i.e., aerosols index) over the Mediterranean region (r2: 0.78, p < 0.001 for Cabrera Island), suggesting that P. oceanica could be an efficient recorder of dust events. A comparison of enrichment factors in rhizomes relative to average crustal material indicates that suspended aerosol is also the most likely source for Cr and Fe to P. oceanica.

  3. Influence of photoperiod and sex on locomotor behavior of meadow voles (Microtus pennsylvanicus) in an automated light-dark 'anxiety' test.

    PubMed

    Ossenkopp, Klaus-Peter; van Anders, Sari M; Engeland, Christopher G; Kavaliers, Martin

    2005-10-01

    This study examined the influence of photoperiod on affective behavior (anxiety) of adult male and female meadow voles (Microtus pennsylvanicus), maintained in either a long or short day photoperiod, when tested in an automated (VersaMax) light-dark test. The light-dark test is based on an innate aversion of rodents to novel, brightly illuminated spaces and has been used with laboratory raised species, such as mice, to assess anxiety and/or fear related behaviors. Male and female meadow voles, housed either in a long day (LD: 16 h light) or short day (SD: 8 h light) photoperiod, were tested in the light-dark apparatus for 30 min on 3 consecutive days. All animals spent significantly (p < 0.001) less time in the brightly lit chamber (900 lux) than in the dark chamber. LD voles, especially females, spent significantly less time in the brightly lit area than did SD voles. Both horizontal and vertical movements occurred less frequently per unit time in the dark area relative to the light, but only in the LD voles. LD female voles were the least active group in the dark area on the first test day but the most active group in the light area, despite spending the least amount of time in this area on the second and third test days. The present results show that LD voles exhibit more anxiety related behaviors in this test situation than do SD voles. LD females avoided the brightly lit area the most, particularly when the apparatus was novel. Thus, both photoperiod and sex influence situation-based anxiety in this species. These findings suggest that meadow voles are an excellent animal model in which to examine the role of gonadal hormones, and their modulation of defence related neural systems, in the induction of anxiety.

  4. Plant community responses to 5 years of simulated climate change in meadow and heath ecosystems at a subarctic-alpine site.

    PubMed

    Jägerbrand, Annika K; Alatalo, Juha M; Chrimes, Dillon; Molau, Ulf

    2009-09-01

    Climate change was simulated by increasing temperature and nutrient availability in an alpine landscape. We conducted a field experiment of BACI-design (before/after control/impact) running for five seasons in two alpine communities (heath and meadow) with the factors temperature (increase of ca. 1.5-3.0 degrees C) and nutrients (5 g N, 5 g P per m(2)) in a fully factorial design in northern Swedish Lapland. The response variables were abundances of plant species and functional types. Plant community responses to the experimental perturbations were investigated, and the responses of plant functional types were examined in comparison to responses at the species level. Nutrient addition, exclusively and in combination with enhanced temperature increase, exerted the most pronounced responses at the species-specific and community levels. The main responses to nutrient addition were increases in graminoids and forbs, whereas deciduous shrubs, evergreen shrubs, bryophytes, and lichens decreased. The two plant communities of heath or meadow showed different vegetation responses to the environmental treatments despite the fact that both communities were located on the same subarctic-alpine site. Furthermore, we showed that the abundance of forbs increased in response to the combined treatment of temperature and nutrient addition in the meadow plant community. Within a single-plant functional type, most species responded similarly to the enhanced treatments although there were exceptions, particularly in the moss and lichen functional types. Plant community structure showed BACI responses in that vegetation dominance relationships in the existing plant functional types changed to varying degrees in all plots, including control plots. Betula nana and lichens increased in the temperature-increased enhancements and in control plots in the heath plant community during the treatment period. The increases in control plots were probably a response to the observed warming during

  5. Low-rate nitrogen input can change the soil CH4 uptake in an alpine meadow ecosystem on Qinghai-Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Fang, H.; Cheng, S.; Yu, G.; Zhu, T.; Zheng, J.

    2010-12-01

    To explore the response of soil methane (CH4) uptake to different nitrogen forms and N addition rates in a N-limiting alpine meadow ecosystem, a low-rate, multi-form N addition experiment was built up. Soil CH4 flux was measured for two growing seasons using the static chamber technique. Soil temperature and moisture at the 10 cm depth were measured simultaneously. Soil inorganic N and dissolved C storage,soil pH and aboveground biomass were determined monthly. Results showed that the alpine meadow soil on Qinghai-Tibetan Plateau behaved as a net sink of atmospheric CH4 ranged -25.5 to -34.8 μgCH4 m-2 h-1. Contrasted to soil moisture, negative relationships between soil CH4 flux and soil temperature, soil NO3--N storage, aboveground biomass and soil pH value. Soil CH4 flux in the alpine meadow was mainly driven by soil moisture, followed by soil pH and NO3--N. Our results suggest that soil acidification is the main biochemical process that driving soil CH4 uptake. Soil NO3--N accumulation has an obvious promotion to soil CH4 uptake. The contribution of CH4 emission by plants to net exchange of CH4 between atmosphere and soil is little. Fig. 1 Seasonal variations of soil CH4 uptake rates in low (a), medium (b), and high N (c) levels and differences of soil CH4 uptake rates between added N treatments and control in 2008 (d), 2009 (e) and 2008-2009 (f). Fig. 2 The relationships between soil CH4 fluxes and environmental variables in two growing seasons.

  6. Biological availability of (238)U, (234)U and (226)Ra for wild berries and meadow grasses in natural ecosystems of Belarus.

    PubMed

    Sokolik, G A; Ovsiannikova, S V; Voinikava, K V; Ivanova, T G; Papenia, M V

    2014-01-01

    This work is devoted to investigation of behavior of (234)U, (238)U and (226)Ra by determining the soil to plant transfer under different natural conditions such as forest or swamped areas and meadow lands with different soil types. The paper summarizes the data on investigation of uranium and radium uptake by wild berries and natural meadow grasses in the typical conditions of Belarus. Parameters characterizing the biological availability of (234)U, (238)U and (226)Ra for bilberry (Vaccinium myrtillus), lingonberry (Vaccinium viti-idaea), blueberry (Vaccinium iliginosum) and cranberry (Vaccinium oxycoccus palustris) as well as for widely occurring mixed meadow vegetation, which belongs to the sedge-grass or grass-sedge associations and forbs, have been established. In the sites under investigation, the deposition levels of (238+239+240)Pu were less than 0.37 kBq m(-2) and (137)Cs deposition ranged between less than 0.37 and 37 kBq m(-2). It was found that activity concentrations of radionuclides in berries varied in the ranges of 0.037-0.11 for (234)U, 0.036-0.10 for (238)U and 0.11-0.43 Bq kg(-1) for (226)Ra, but in the mixed meadow grasses they were 0.32-4.4, 0.24-3.9 and 0.14-6.9 Bq kg(-1) accordingly. The (234)U/(238)U activity ratios were 1.02 ± 0.01 for wild berries, 1.20 ± 0.09 for underground meadow grasses and 1.02 ± 0.02 for proper soils. The concentration ratios (CRs, dry weight basis) of (234)U and (238)U for mixed meadow grasses were 0.036-0.42 and 0.041-0.46 respectively. The correspondent geometric means (GM) were 0.13 and 0.15 with geometric standard deviations (GSD) of 2.4. The CRs of (226)Ra for meadow grasses were 0.031-1.0 with GM 0.20 and GSD 2.6. The CRs of (234)U, (238)U and (226)Ra for wild berries ranged within 0.0018-0.008 (GM is 0.0034, GSD is 1.8), 0.0018-0.008 (GM is 0.0035, GSD is 1.8) and 0.005-0.033 (GM is 0.016, GSD is 2.1) accordingly. The highest CR values of uranium for mixed meadow grasses were found in the

  7. Biological availability of (238)U, (234)U and (226)Ra for wild berries and meadow grasses in natural ecosystems of Belarus.

    PubMed

    Sokolik, G A; Ovsiannikova, S V; Voinikava, K V; Ivanova, T G; Papenia, M V

    2014-01-01

    This work is devoted to investigation of behavior of (234)U, (238)U and (226)Ra by determining the soil to plant transfer under different natural conditions such as forest or swamped areas and meadow lands with different soil types. The paper summarizes the data on investigation of uranium and radium uptake by wild berries and natural meadow grasses in the typical conditions of Belarus. Parameters characterizing the biological availability of (234)U, (238)U and (226)Ra for bilberry (Vaccinium myrtillus), lingonberry (Vaccinium viti-idaea), blueberry (Vaccinium iliginosum) and cranberry (Vaccinium oxycoccus palustris) as well as for widely occurring mixed meadow vegetation, which belongs to the sedge-grass or grass-sedge associations and forbs, have been established. In the sites under investigation, the deposition levels of (238+239+240)Pu were less than 0.37 kBq m(-2) and (137)Cs deposition ranged between less than 0.37 and 37 kBq m(-2). It was found that activity concentrations of radionuclides in berries varied in the ranges of 0.037-0.11 for (234)U, 0.036-0.10 for (238)U and 0.11-0.43 Bq kg(-1) for (226)Ra, but in the mixed meadow grasses they were 0.32-4.4, 0.24-3.9 and 0.14-6.9 Bq kg(-1) accordingly. The (234)U/(238)U activity ratios were 1.02 ± 0.01 for wild berries, 1.20 ± 0.09 for underground meadow grasses and 1.02 ± 0.02 for proper soils. The concentration ratios (CRs, dry weight basis) of (234)U and (238)U for mixed meadow grasses were 0.036-0.42 and 0.041-0.46 respectively. The correspondent geometric means (GM) were 0.13 and 0.15 with geometric standard deviations (GSD) of 2.4. The CRs of (226)Ra for meadow grasses were 0.031-1.0 with GM 0.20 and GSD 2.6. The CRs of (234)U, (238)U and (226)Ra for wild berries ranged within 0.0018-0.008 (GM is 0.0034, GSD is 1.8), 0.0018-0.008 (GM is 0.0035, GSD is 1.8) and 0.005-0.033 (GM is 0.016, GSD is 2.1) accordingly. The highest CR values of uranium for mixed meadow grasses were found in the

  8. Selected kinetic parameters of soil microbial respiration in the A horizon of differently managed mountain forests and meadows of Moravian-Silesian Beskids Mts.

    NASA Astrophysics Data System (ADS)

    Vranová, V.; Formánek, P.; Rejšek, K.; Kisza, L.

    2009-03-01

    The aim of this study was to find out the effect of intensity of thinning (FD-dense stand = 2044 trees/ha; FS-open stand = 1652 trees/ha) performed in young forest stands (99% spruce, 1% fir) in Moravian-Silesian Beskids Mts. (908 m a.s.l.; 49°30'10″ N, 18°32'20″ E) on V DS (C mineralization rate immediately after drying and re-wetting of soil), V BR (basal soil respiration at 60% w/w soil water content measured 5th day after rewetting of dry soil), V MAX (maximum respiration rate after glucose addition measured from 6th day after rewetting of dry soil), V DS/ V MAX (heterotrophic respiratory potential) and ACDS/ACBR (the potential flush of biologically available C) in Ae horizon of Haplic and Entic Podzols. The ACDS/ACBR was calculated from three 24-hour respirations of 7-day incubation according to the equation ACDS/ACBR= V DS V MAX/(2 V BR( V MAX- V DS)). The aim of the work was also to find the effect of circa 11-year abandonment of a mountain meadow in the locality (825-860 m a.s.l.; 49°30'17″ N, 18°32'28″ E) on the same parameters in Ah horizon of Gleyic Luvisol. The studied parameters were measured in the course of the vegetation season 2004 (May-September) at 30-day intervals. The higher intensity of thinning caused alternately higher or lower or very similar values of V DS, V BR, V MAX, V DS/ V MAX and ACDS/ACBR in the course of the season. The abandonment of the meadow increased V DS, V BR, V MAX throughout the whole experiment. V DS/ V MAX increased due to the abandonment except for the last sampling in September. Alternately higher or lower or very similar values of ACDS/ACBR in course of the season appeared on abandoned or moderately mown meadows. The lower intensity of thinning or abandonment of the meadow were connected with increasing number of significant ( P < 0.05) correlations between the studied properties.

  9. Balsam Meadow development of the Big Creek Project, FERC. No. 67, California

    SciTech Connect

    Not Available

    1982-11-01

    An abstract of the final environmental impact statement (EIS) on the construction of a 200 MW hydroelectric plant in Fresno County, California describes the effects of a 60-acre reservoir, 120-foot-high dam, a mile-long diversion tunnel, and other structures associated with power generation and distribution. The utility would benefit from the additional capacity, while the area would have new employment opportunities during the construction period and nearly one million dollars in new property tax revenue. Negative impacts include the loss of 80 acres of land, 97 acres of wildlife habitat, the diversion of lake water, and the loss of cultural and historical sites. Legal mandates for the EIS are the DOE Organization Act of 1977, Federal Power Act of 1920, and National Historic Preservation Act of 1966.

  10. 78 FR 12714 - Intermountain Region, Payette National Forest, New Meadows Ranger District, Idaho; Lost Creek...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... commercial and noncommercial vegetation management and road system modifications and maintenance. DATES...) reduce road-related accelerated sediment and other road related impacts; (6) restore riparian vegetation... woodpecker, and to move vegetation toward the desired conditions specified in the Payette National...

  11. Development and Application of a Habitat Suitability Ranking Model for the New Mexico Meadow Jumping Mouse (Zapus hudsonius luteus)

    SciTech Connect

    James Biggs; Mary Mullen; Kathryn Bennett

    1999-11-01

    The New Mexico meadow jumping mouse (Zapus hudsonius luteus) is currently listed as a state threatened species in New Mexico and has been identified as potentially occurring within the Los Alamos National Laboratory (LANL) boundary. We describe the development of a model to identify and rank habitat at LANL that may be suitable for occupation by this species. The model calculates a habitat suitability ranking (HSR) based on total plant cover, plant species composition, total number of plant species, and plant height. Input data for the model is based on the measurement of these variables at known locations where this species has been found within the Jemez Mountains. Model development included the selection of habitat variables, developing a probability distribution for each variable, and applying weights to each variable based on their overall importance in defining the suitability of the habitat. The habitat variables (HV) include plant cover (HV1), grass/forb cover (HV2), plant height (HV3), number of forbs (HV4), number of grasses (HV5), and sedge/rush cover (HV6). Once the HVs were selected, probability values were calculated for each. Each variable was then assigned a ''weighting factor'' to reflect the variables' importance relative to one another with respect to contribution to quality of habitat. The least important variable, sedge/rush cover, was assigned a weight factor of ''1'' with increasing values assigned to each remaining variable as follows: number of forbs = 3, number of grasses = 3, plant height = 5, grass/forb cover = 6, and total plant cover = 7. Based on the probability values and weighting factors, a HSR is calculated as follows: HSR = (P{sub HV1}(7) + P{sub HV2}(6) + P{sub HV3}(5) + P{sub HV4}(3) + P{sub HV5}(3) + P{sub HV6}(1)). Once calculated, the HSR values are placed into one of four habitat categorical groupings by which management strategies are applied.

  12. Local point sources that affect ground-water quality in the East Meadow area, Long Island, New York

    USGS Publications Warehouse

    Heisig, Paul M.

    1994-01-01

    The extent and chemical characteristics of ground water affected by three local point sources--a stormwater basin, uncovered road-salt-storage piles, and an abandoned sewage-treatment plant--were delineated during a 3-year study of the chemical characteristics and migration of a body of reclaimed wastewater that was applied to the watertable aquifer during recharge experiments from October 1982 through January 1984 in East Meadow. The timing, magnitude, and chemical quality of recharge from these point sources is highly variable, and all sources have the potential to skew determinations of the quality of ambient ground-water and of the reclaimed-wastewater plume if they are not taken into account. Ground water affected by recharge from the stormwater basin is characterized by low concentrations of nitrate + nitrite (less than 5 mg/L [milligrams per liter] as N) and sulfate (less than 40 mg/L) and is almost entirely within the upper glacial aquifer. The plume derived from road-salt piles is narrow, has high concentrations of chloride (greater than 50 mg/L) and sodium (greater than 75 mg/L), and also is limited to the upper glacial aquifer. The sodium, in high concentrations, could react with aquifer material and exchange for sorbed cations such as calcium, potassium, and magnesium. Water affected by secondary-treated sewage from the abandoned treatment plant extends 152 feet below land surface into the upper part of the Magothy aquifer and longitudinally beyond the southern edge of the study area, 7,750 feet south of the recharge site. Ground water affected by secondary-treated sewage within the study area typically contains elevated concentrations of reactive chemical constituents, such as potassium and ammonium, and low concentrations of dissolved oxygen. Conservative or minimally reactive constituents such as chloride and sodium have been transported out of the study area in the upper glacial aquifer and the intermediate (transitional) zone but remain in the less

  13. Design, operation, and monitoring capability of an experimental artificial-recharge facility at East Meadow, Long Island, New York

    USGS Publications Warehouse

    Schneider, B.J.; Oaksford, E.T.

    1986-01-01

    Artificial recharge with tertiary-treated sewage is being tested at East Meadow to evaluate the physical and chemical effects on the groundwater system. The recharge facility contains 11 recharge basins and 5 injection wells and is designed to accept 4 million gallons of reclaimed water per day. Of the 11 basins, 7 are recently constructed and will accept 0.5 million gallons per day each. An observation manhole (12-foot inside diameter and extending 16 feet below the basin floor) was installed in each of two basins to enable monitoring and sampling of percolating reclaimed water in the unsaturated zone with instruments such as tensiometers, gravity lysimeters, thermocouples, and soil-gas samplers. Five shallow (100-feet deep) injection wells will each return 0.5 million gallons per day to the groundwater reservoir. Three types of injection-well design are being tested; the differences are in the type of gravel pack around the well screen. When clogging at the well screen occurs, redevelopment should restore the injection capability. Flow to the basins and wells is regulated by automatic flow controllers in which a desired flow rate is maintained by electronic sensors. Basins can also operate in a constant-head mode in which a specified head is maintained in the basin automatically. An observation-well network consisting of 2-inch- and 6-inch-diameter wells was installed within a 1-square-mile area at the recharge facility to monitor aquifer response and recharge. During 48 days of operation within a 17-week period (October 1982 through January 1983), 88.5 million gallons of reclaimed water was applied to the shallow water table aquifer through the recharge basins. A 4.29-foot-high groundwater mound developed during a 14-day test; some water level increase associated with the mound was detected 1,000 ft from the basins. Preliminary water quality data from wells affected by reclaimed water show evidence that mechanisms of mixing, dilution, and dispersion are

  14. Water and carbon dioxide fluxes over an alpine meadow in southwest China and the impact of a spring drought event

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Liu, Huizhi; Sun, Jihua; Feng, Jianwu

    2016-02-01

    Based on the eddy covariance measurements f