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At least 829 records · Page 46Linked to original sources
USGS2011

Vegetation communities at Big Muddy National Fish and Wildlife Refuge, Missouri

New and existing data were used to describe and map vegetation communities at Big Muddy National Fish and Wildlife Refuge. Existing data had been gathered during the growing seasons of 2002, 2003, and 2004. New data were collected in 2007 to describe previously unsampled communities and communities within which insufficient data had been collected. Plot data and field observations were used to describe 17 natural and semi-natural communities at the Association level of the National Vegetation Classification System (NVCS). Four ruderal communities not included in the NVCS are also described. Data were used to inform delineation of communities using aerial photos from 2000, 2002, 2003, 2005, 2006, and 2007. During this process, eleven additional land cover classes including cultural features, managed vegetation communities, and water features were identified. These features were mapped, some were described, but no vegetation data were collected. In 2009, nearly all community polygons were field visited and classified to the Association level. When necessary, polygon boundaries were adjusted based on field observations. The final map includes 482 polygons of 27 land cover classes encompassing 3,174 hectares on 5 units of the refuge. Data and information will inform the development of the refuge Comprehensive Conservation Plan.

Missouri↗
USGS2011

A study of topics for distance education-A survey of U.S. Fish and Wildlife Service employees

The purpose of this study was to identify training topics and distance education technologies preferred by U.S. Fish and Wildlife Service employees. This study was conducted on behalf of the National Conservation Training Center to support their distance education strategy planning and implementation. When selecting survey recipients, we focused on employees in positions involving conservation and environmental education and outreach programming. We conducted the study in two phases. First, we surveyed 72 employees to identify useful training topics. The response rate was 61 percent; respondents were from all regions and included supervisors and nonsupervisors. Five topics for training were identified: creating and maintaining partnerships (partnerships), technology, program planning and development (program planning), outreach methods to engage the community (outreach methods), and evaluation methods. In the second phase, we surveyed 1,488 employees to assess preferences for training among the five topics identified in the first survey and preferences among six distance education technologies: satellite television, video conferencing, audio conferencing, computer mediated training, written resources, and audio resources. Two types of instructor-led training were included on the survey to compare to the technology options. Respondents were asked what types of information, such as basic facts or problem solving skills, were needed for each of the five topics. The adjusted response rate was 64 percent; respondents were from all regions and included supervisors and nonsupervisors. The results indicated clear preferences among respondents for certain training topics and technologies. All five training topics were valued, but the topics of partnerships and technology were given equal value and were valued more than the other three topics. Respondents indicated a desire for training on the topics of partnerships, technology, program planning, and outreach methods. For the six distance education technologies, respondents indicated different levels of usability and access. Audio conferencing and written resources were reported to be most usable and accessible. The ratings of technology usability/access differed according to region; respondents in region 9 rated most technologies higher on usability/access. Respondents indicated they would take courses through either onsite or distance education approaches, but they prefer onsite training for most topics and most types of information.

Open-File Report↗
USGS2011

Conceptual ecological models to support detection of ecological change on Alaska National Wildlife Refuges

More than 31 million hectares of land are protected and managed in 16 refuges by the U.S. Fish and Wildlife Service (USFWS) in Alaska. The vastness and isolation of Alaskan refuges give rise to relatively intact and complete ecosystems. The potential for these lands to provide habitat for trust species is likely to be altered, however, due to global climate change, which is having dramatic effects at high latitudes. The ability of USFWS to effectively manage these lands in the future will be enhanced by a regional inventory and monitoring program that integrates and supplements monitoring currently being implemented by individual refuges. Conceptual models inform monitoring programs in a number of ways, including summarizing important ecosystem components and processes as well as facilitating communication, discussion and debate about the nature of the system and important management issues. This process can lead to hypotheses regarding future changes, likely results of alternative management actions, identification of monitoring indicators, and ultimately, interpretation of monitoring results. As a first step towards developing a monitoring program, the 16 refuges in Alaska each created a conceptual model of their refuge and the landscape context. Models include prominent ecosystem components, drivers, and processes by which components are linked or altered. The Alaska refuge system also recognizes that designing and implementing monitoring at regional and ecoregional extents has numerous scientific, fiscal, logistical, and political advantages over monitoring conducted exclusively at refuge-specific scales. Broad-scale monitoring is particularly advantageous for examining phenomena such as climate change because effects are best interpreted at broader spatial extents. To enable an ecoregional perspective, a rationale was developed for deriving ecoregional boundaries for four ecoregions (Polar, Interior Alaska, Bering Coast, and North Pacific Coast) from the Unified Ecoregions of Alaska. Ecoregional models were then developed to illustrate resources and processes that operate at spatial scales larger than individual refuges within each ecoregion. Conceptual models also were developed for adjacent marine areas, designated as the North Pacific, Bering Sea, and Beaufort-Chukchi Sea Marine Ecoregions. Although many more conceptual models will be required to support development of a regional monitoring program, these definitions of ecoregions and associated conceptual models are an important foundation.

Alaska↗
USGS2011

Trends and causes of historical wetland loss, Sabine National Wildlife Refuge, southwest Louisiana

Prior U.S. Geological Survey studies (Open-File Reports 2005-1216 and 2009-1158) examined historical land- and water-area changes and estimated magnitudes of land subsidence and erosion at 10 wetland sites in the Mississippi River delta plain. The present study extends that work by analyzing interior wetland loss and relative magnitudes of subsidence and erosion at five additional wetland sites in Sabine National Wildlife Refuge (SNWR) in the western chenier plain. The study sites were selected because their geologic setting differed from that of the delta plain; also, although the refuge marshes had been managed partly to minimize wetland loss, interior wetland losses there were extensive. Historical aerial photography, datum-corrected marsh elevations and water depths, and sediment cores were integrated to evaluate historical land- and water-area changes at SNWR. The thickness of the uppermost Holocene sediments (peat and organic-rich mud) and the elevation of stratigraphic contacts were compared at marsh and open-water sites across areas of formerly continuous marsh to estimate magnitudes of recent elevation loss caused by vertical erosion and subsidence. Results of these analyses indicate that erosion greatly exceeded subsidence at most of the core sites, although both processes have contributed to historical wetland loss. Comparison of these results with results of our prior studies indicates that magnitudes of subsidence and total accommodation space that formed in the western chenier plain were less than those in the delta plain. Compared with the delta plain, where subsidence generally exceeded erosion and peat thicknesses were so great that peat was preserved even where erosion was greater than subsidence, the SNWR peats are thin and were absent (eroded) at most open-water sites. Although historical subsidence rates in the chenier plain are substantially lower than most of the same rates in the delta plain, the temporal and spatial trends of rapid wetland loss, highest rates of land-surface subsidence, and high rates of oil-and-gas production are similar, indicating that historical wetland loss was likely initiated by similar processes (deep-subsurface subsidence) in both regions.

Open-File Report↗
USGS2011

Constraints to connecting children with nature--Survey of U.S. Fish and Wildlife Service employees sponsored by the National Conservation Training Center, Division of Education Outreach

The U.S. Fish and Wildlife Service (FWS) names "connecting people with nature" as one of its top six priorities in the online Service Employee Pocket Guide. The National Conservation Training Center (NCTC) took the initiative to identify issues that impede greater progress in addressing constraints to connecting children with nature. The Division of Education Outreach at NCTC formed a working relation with the Policy Analysis and Science Assistance branch of the U.S. Geological Survey to conduct a study on these issues. To meet the objectives of the study, a survey of a sample of FWS employees was conducted. This report includes the description of how the survey was developed and administered, how the data were analyzed, and a discussion of the survey results. The survey was developed based on published literature and incorporated input from two working groups of professionals focused on the issue of connecting children with nature. Although the objective as stated by the FWS is to connect people with nature, the survey primarily focused on connecting children, rather than all people, with nature. The four primary concepts included on the survey were interpretation of how the FWS defined "connection" as part of its mission, perceived success with outreach, constraints to connecting children with nature, and importance of connecting children with nature. The survey was conducted online using KeySurvey© software. The survey was sent to 604 FWS employees. Responses were received from 320 employees. The respondents represented diversity in regions, tenure, wage/grade level, job series, supervisory status, and involvement with education and outreach activities. The key findings of the survey are as follows: * FWS employees believe they as individuals and the agency are successful now and will be more successful in the future in connecting children with nature. * FWS employees believe that there are many outcomes that are relevant to the FWS objective to connect people with the environment. * FWS employees believe that connecting children with nature is important. * Constraints to connecting children with nature exist but are not perceived by respondents to be severe. * The constraints of greatest concern are practical issues, competition from technology, funding issues and staffing issues.

Open-File Report↗
USGS2012

Summary of oceanographic and water-quality measurements near the Blackwater National Wildlife Refuge, Maryland, 2011

Suspended-sediment transport is a critical element governing the geomorphology of tidal marshes. Marshes rely on both organic material and inorganic sediment deposition to maintain their elevation relative to sea level. In wetlands near the Blackwater National Wildlife Refuge, Maryland, portions of the salt marsh have been subsiding relative to sea level since the early 20th century. Other portions of the marsh have been successful at maintaining elevation. The U.S. Geological Survey performed observational deployments to measure suspended-sediment concentration in the tidal channels in order to understand the magnitude of suspended-sediment concentrations, the sediment-transport mechanisms, and differences between two marsh areas, one that subsided and one that maintained elevation. We deployed optical turbidity sensors and acoustic velocity meters at multiple sites over two periods in 2011. This report presents the time-series of oceanographic data collected during those field studies, including velocity, depth, turbidity, salinity, water temperature, and pH.

Maryl↗
USGS2012

Soil data for a collapse-scar bog chronosequence in Koyukuk Flats National Wildlife Refuge, Alaska, 2008

Peatlands in the northern permafrost region store large amounts of organic carbon, most of which is currently stored in frozen peat deposits. Recent warming at high-latitudes has accelerated permafrost thaw in peatlands, which will likely result in the loss of soil organic carbon from previously frozen peat deposits to the atmosphere. Here, we report soil organic carbon inventories, soil physical data, and field descriptions from a collapse-scar bog chronosequence located in a peatland ecosystem at Koyukuk Flats National Wildlife Refuge in Alaska.

Alaska↗
USGS2012

Assessment of photographs from wildlife monitoring cameras in Drakes Estero, Point Reyes National Seashore, California

Between 2007 and 2010, National Park Service (NPS) staff at the Point Reyes National Seashore, California, collected over 300,000 photographic images of Drakes Estero from remotely operated wildlife monitoring cameras. The purpose of the systems was to obtain photographic data to help understand possible relationships between anthropogenic activities and Pacific harbor seal ( Phoca vitulina richardsi ) behavior and distribution. The value of the NPS photographs for use in assessing the frequency and impacts of seal disturbance and displacement in Drakes Estero has been debated. In September 2011, the NPS determined that the photographs did not provide meaningful information for development of a Draft Environmental Impact Statement (DEIS) for the Drakes Bay Oyster Company Special Use Permit. Limitations of the photographs included lack of study design, poor photographic quality, inadequate field of view, incomplete estuary coverage, camera obstructions, and weather limitations. The Marine Mammal Commission (MMC) reviewed the scientific data underpinning the Drakes Bay Oyster Company DEIS in November 2011 and recommended further analysis of the NPS photographs for use in characterizing rates and consequences of seal disturbance (Marine Mammal Commission, 2011). In response to that recommendation, the NPS asked the U.S. Geological Survey (USGS) to conduct an independent review of the photographs and render an opinion on the utility of the remote camera data for informing the environmental impact analyses included in the DEIS. In consultation with the NPS, we selected the 2008 photographic dataset for detailed evaluation because it covers a full harbor seal breeding season (March 1 to June 30), provides two fields of view (two cameras were deployed), and represents a time period when cameras were most consistently deployed and maintained. The NPS requested that the photographs be evaluated in absence of other data or information pertaining to seal and human activity in the estuary and that we focus on the extent to which the photographs could be used in understanding the relationship between human activity (including commercial oyster production) and harbor seal disturbance and distribution in the estuary.

California↗
USGS2013

Air temperature, wind speed, and wind direction in the National Petroleum Reserve—Alaska and the Arctic National Wildlife Refuge, 1998–2011

This report provides air temperature, wind speed, and wind direction data collected on Federal lands in Arctic Alaska over the period August 1998 to July 2011 by the U.S. Department of the Interior's climate monitoring array, part of the Global Terrestrial Network for Permafrost. In addition to presenting data, this report also describes monitoring, data collection, and quality control methodology. This array of 16 monitoring stations spans 68.5°N to 70.5°N and 142.5°W to 161°W, an area of roughly 150,000 square kilometers. Climate summaries are presented along with provisional quality-controlled data. Data collection is ongoing and includes several additional climate variables to be released in subsequent reports, including ground temperature and soil moisture, snow depth, rainfall, up- and downwelling shortwave radiation, and atmospheric pressure. These data were collected by the U.S. Geological Survey in close collaboration with the Bureau of Land Management and the U.S. Fish and Wildlife Service.

Alaska↗
USGS2015

Summary of oceanographic and water-quality measurements in Rachel Carson National Wildlife Refuge, Wells, Maine, in 2013

Suspended-sediment transport is a critical element controlling the geomorphology of tidal wetland complexes. Wetlands rely on organic material and inorganic sediment deposition to maintain their elevation relative to sea level. The U.S. Geological Survey performed observational deployments to measure suspended-sediment concentration and water flow rates in the tidal channels of the wetlands in the Rachel Carson National Wildlife Refuge in Wells, Maine. The objective was to characterize the sediment-transport mechanisms that contribute to the net sediment budget of the wetland complex. We deployed a meteorological tower, optical turbidity sensors, and acoustic velocity meters at sites on Stephens Brook and the Ogunquit River between March 27 and December 9, 2013. This report presents the time-series oceanographic and atmospheric data collected during those field studies. The oceanographic parameters include water velocity, depth, turbidity, salinity, temperature, and pH. The atmospheric parameters include wind direction, speed, and gust; air temperature; air pressure; relative humidity; short wave radiation; and photosynthetically active radiation.

Maine↗
USGS2015

Conceptual data modeling of wildlife response indicators to ecosystem change in the Arctic

Large research studies are often challenged to effectively expose and document the types of information being collected and the reasons for data collection across what are often a diverse cadre of investigators of differing disciplines. We applied concepts from the field of information or data modeling to the U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative to prototype an application of information modeling. The USGS CAE initiative is collecting information from marine and terrestrial environments in Alaska to identify and understand the links between rapid physical changes in the Arctic and response of wildlife populations to these ecosystem changes. An associated need is to understand how data collection strategies are informing the overall science initiative and facilitating communication of those strategies to a wide audience. We explored the use of conceptual data modeling to provide a method by which to document, describe, and visually communicate both enterprise and study level data; provide a simple means to analyze commonalities and differences in data acquisition strategies between studies; and provide a tool for discussing those strategies among researchers and managers.

Alaska↗
USGS2016

Analysis of seafloor change at Breton Island, Gosier Shoals, and surrounding waters, 1869–2014, Breton National Wildlife Refuge, Louisiana

Characterizing bathymetric change in coastal environments is an important component in understanding shoreline evolution, especially along barrier island platforms. Bathymetric change is a function of the regional sediment budget, long-term wave and current patterns, and episodic impact from high-energy events such as storms. Human modifications may also cause changes in seafloor elevation. This study, conducted by the U.S. Geological Survey in collaboration with the U.S. Fish and Wildlife Service, evaluates bathymetric and volumetric change and sediment characteristics around Breton Island and Gosier Shoals located offshore of the Mississippi River Delta in Louisiana. This area has been affected by significant storm events such as Hurricane Katrina in 2005. Sedimentation patterns at Breton Island and offshore have also been modified by the excavation of a shipping channel north of the island. Four time periods are considered that encompass these episodes and include long-term change and short-term storm recovery: 1869–2014, 1869–1920, 1920–2014, and 2007–2014. Finally, sediment characteristics are reported in the context of seafloor elevation.

Louisana↗
USGS2017

Integrated wetland management for waterfowl and shorebirds at Mattamuskeet National Wildlife Refuge, North Carolina

Mattamuskeet National Wildlife Refuge (MNWR) offers a mix of open water, marsh, forest, and cropland habitats on 20,307 hectares in coastal North Carolina. In 1934, Federal legislation (Executive Order 6924) established MNWR to benefit wintering waterfowl and other migratory bird species. On an annual basis, the refuge staff decide how to manage 14 impoundments to benefit not only waterfowl during the nonbreeding season, but also shorebirds during fall and spring migration. In making these decisions, the challenge is to select a portfolio, or collection, of management actions for the impoundments that optimizes use by the three groups of birds while respecting budget constraints. In this study, a decision support tool was developed for these annual management decisions. Within the decision framework, there are three different management objectives: shorebird-use days during fall and spring migrations, and waterfowl-use days during the nonbreeding season. Sixteen potential management actions were identified for impoundments; each action represents a combination of hydroperiod and vegetation manipulation. Example hydroperiods include semi-permanent and seasonal drawdowns, and vegetation manipulations include mechanical-chemical treatment, burning, disking, and no action. Expert elicitation was used to build a Bayesian Belief Network (BBN) model that predicts shorebird- and waterfowl-use days for each potential management action. The BBN was parameterized for a representative impoundment, MI-9, and predictions were re-scaled for this impoundment to predict outcomes at other impoundments on the basis of size. Parameter estimates in the BBN model can be updated using observations from ongoing monitoring that is part of the Integrated Waterbird Management and Monitoring (IWMM) program. The optimal portfolio of management actions depends on the importance, that is, weights, assigned to the three objectives, as well as the budget. Five scenarios with a variety of objective weights and budgets were developed. Given the large number of possible portfolios (16 14 ), a heuristic genetic algorithm was used to identify a management action portfolio that maximized use-day objectives while respecting budget constraints. The genetic algorithm identified a portfolio of management actions for each of the five scenarios, enabling refuge staff to explore the sensitivity of their management decisions to objective weights and budget constraints. The decision framework developed here provides a transparent, defensible, and testable foundation for decision making at MNWR. The BBN model explicitly structures and parameterizes a mental model previously used by an expert to assign management actions to the impoundments. With ongoing IWMM monitoring, predictions from the model can be tested, and model parameters updated, to reflect empirical observations. This framework is intended to be a living document that can be updated to reflect changes in the decision context (for example, new objectives or constraints, or new models to compete with the current BBN model). Rather than a mandate to refuge staff, this framework is intended to be a decision support tool; tool outputs can become part of the deliberations of refuge staff when making difficult management decisions for multiple objectives.

North Carolina↗
USGS2018

U.S. Department of the Interior Climate Science Centers and U.S. Geological Survey National Climate Change and Wildlife Science Center—Annual report for 2017

Introduction The year 2017 was a year of review and renewal for the Department of the Interior (DOI) Climate Science Centers (CSCs) and the U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center (NCCWSC). The Southeast, Northwest, Alaska, Southwest, and North Central CSCs’ 5-year summary review reports were released in 2017 and contain the findings of the external review teams led by the Cornell University Human Dimensions Research Unit in conjunction with the American Fisheries Society. The reports for the Pacific Islands, South Central, and Northeast CSCs are planned for release in 2018. The reviews provide an opportunity to evaluate aspects of the cooperative agreement, such as the effectiveness of the CSC in meeting project goals and assessment of the level of scientific contribution and achievement. These reviews serve as a way for the CSCs and NCCWSC to look for ways to recognize and enhance our network’s strengths and identify areas for improvement. The reviews were followed by the CSC recompetition, which led to new hosting agreements at the Northwest, Alaska, and Southeast CSCs. Learn more about the excellent science and activities conducted by the network centers in the 2017 annual report.

Open-File Report↗
USGS2018

Movements and habitat use locations of manatees within Kings Bay Florida during the Crystal River National Wildlife Refuge winter season (November 15–March 31)

Kings Bay, Florida, is one of the most important natural winter habitat locations for the federally threatened Trichechus manatus latirostris (Florida manatee). Crystal River National Wildlife Refuge was established in 1983 specifically to provide protection for manatees and their critical habitat. To aid managers at the refuge and other agencies with this task, spatial analyses of local habitat use locations and travel corridors of manatees in Kings Bay during manatee season (November 15–March 31) are presented based on Global Positioning System telemetry of 41 manatees over a 12-year timespan (2006−18). Local habitat use areas and travel corridors differed spatially when Gulf of Mexico water temperatures were cold (less than or equal to 17 degrees Celsius) versus when they were warm (greater than 17 degrees Celsius). During times of cold water, manatees were found in higher concentrations in the main springs and canals throughout the eastern side of the bay, whereas when waters were warm, they were found more generally throughout the bay and into Crystal River, except for the central open part of the bay and the southwest corner.

Florida↗
USGS2018

A comparison of photograph-interpreted and IfSAR-derived maps of polar bear denning habitat for the 1002 Area of the Arctic National Wildlife Refuge, Alaska

Polar bears ( Ursus maritimus ) in Alaska use the Arctic National Wildlife Refuge (ANWR) for maternal denning. Pregnant bears den in snow banks for more than 3 months in winter during which they give birth to and nurture young. Denning is one of the most vulnerable times in polar bear life history as the family group cannot simply walk away from a disturbance without jeopardizing survival of newly born cubs. The ANWR includes the “1002 Area”, a region recently opened for oil and gas exploration by the U.S. Department of the Interior (DOI). As a part of its mission, the DOI “… protects and manages the Nation's natural resources …” and is therefore responsible for conserving polar bears and encouraging development of energy potential. Because future industrial activities could overlap habitats used by denning polar bears, identifying these habitats can inform the decisions of resource managers tasked to develop resources and protect polar bears. To help inform these efforts, we qualitatively compared the distribution of denning habitat identified by two different methods: previously published habitat from manual interpretation of aerial photographs, and habitat derived by computer interrogation of interferometric synthetic aperture radar (IfSAR) digital terrain models (DTM). Because photograph-interpreted methods depicted denning habitat as a line and IfSAR-derived methods depicted habitat as a polygon, we assessed agreement between the two methods with distance measurements. We found that 77.5 percent of IfSAR-derived denning habitat (79.6 km2 ; 1.2 percent of the 6,837.0 km2 1002 Area) was within 600 m of photograph-interpreted habitat (3,026.9 km), including 53.9 percent within 200 m. This distribution differed from that of randomly distributed points, as only 49.4 percent of these occurred within 600 m of photograph-interpreted habitat, including 18.3 percent within 200 m. Both methods appear to identify the major physiographic features that polar bears might select for denning. IfSAR-derived methods identified habitat at greater frequency beyond major landscape features such as coastal bluffs, river banks and lakeshores, were more likely to identify isolated pockets of putative denning habitat, and were easier to implement than deriving habitat from photograph-interpretive efforts. However, previous research suggests that photograph-interpretation methods may identify denning habitat more correctly than computer interrogation of IfSAR DTMs. Future work should quantify the distribution of IfSAR-derived denning habitat relative to actual landscape features and polar bear maternal dens in the 1002 Area, and investigate the feasibility of habitat identification from finer grained DTMs.

Alaska↗
USGS2018

Status of selenium in south San Francisco Bay—A basis for modeling potential guidelines to meet National tissue criteria for fish and a proposed wildlife criterion for birds

The U.S. Environmental Protection Agency (EPA) proposed Aquatic Life and AquaticDependent Wildlife Criteria for Selenium (Se) in California’s San Francisco Bay and Delta (Bay-Delta) in June 2016. Here we apply the same modeling methodology—Ecosystem-Scale Selenium Modeling— to an assessment of conditions and documentation of food webs of south San Francisco Bay (South Bay) as an exploratory framework in support of site-specific Se criteria development. Long-term datasets contribute to the basis for modeling, especially the 21-year collection of the clam Macoma petalum from a mudflat at the lower end of South Bay (Lower South Bay). As such, this is a working document that may serve as a basis to establish an understanding of the specifics of Se biodynamics within the estuary and reduce uncertainties about how to protect it. This approach brings together the main factors involved in toxicity: likelihood of high exposure, inherent species sensitivity, and the behavioral ecology (for example, demographics and life history) of an organism in terms of susceptibility to a reproductive toxicant. Species sensitivity is represented here by use of the EPA’s current national tissue Se criterion for fish or that proposed to protect the eggs of aquatic birds for the Bay-Delta (U.S. Environmental Protection Agency, 2016a, 2016b, 2016c). This report also strives to bring together findings and field data across a body of literature for South Bay to provide an integrative assessment. We find an assemblage of site-specific conditions that could affect modeling: associated urban processes such as discharges from municipal wastewater treatment plants and drainage from mercury (Hg) mining and limestone extraction are sources of Se that characterize the Lower South Bay as the location of interest for Se exposure; • hydrodynamics are lagoon-like (that is, less flushing), which sustains elevated nutrients and phytoplankton blooms; • managed freshwater sources are a major hydrodynamic component; • birds, in addition to fish, are prominent predators in South Bay; • wetland restoration has recently intervened to play a significant role in ecosystem function that may include uptake of both Hg and Se; • the dietary food web of surficial-sediment to M. petalum is important because of the dominance of this clam species and its elevated Se bioaccumulation potential compared to other local food webs; and 2 • maximal Se concentrations may be limited by transitory or annually renewed food webs (for example, migratory shorebirds and decimation of clams from marshes). We also find that the constructed mechanistic model: • spatially connects to the Palo Alto mudflat site because of data availability; • accurately predicts average observed Se concentrations in M. petalum and in predator species of fish and birds; and • is able to bracket a range of potential protective water-column Se concentrations specific to predator species based on the EPA’s national Se criterion for whole-body fish tissue and a proposed site-specific criterion for bird eggs in the Bay-Delta.

California↗
USGS2018

Adaptive management in native grasslands managed by the U.S. Fish and Wildlife Service—Implications for grassland birds

Burning and grazing are natural processes in native prairies that also serve as important tools in grassland management to conserve plant diversity, to limit encroachment of woody and invasive plants, and to maintain or improve prairies. Native prairies managed by the U.S. Fish and Wildlife Service (FWS) in the Prairie Pothole Region of the northern Great Plains have been extensively invaded by nonnative, cool-season species of grasses. These invasions were believed to reflect a common management history of long-term rest and little or no defoliation by natural processes (burning and grazing). To address the challenges associated with these invasive species, the FWS embraced a collaborative approach in 2008, in partnership with U.S. Geological Survey, to restore native prairies on lands managed by FWS. This approach is known as the Native Prairie Adaptive Management (NPAM) initiative and was based on the application of an adaptive decision-support framework to assist managers in selecting management actions despite uncertainty and in maximizing learning from management outcomes. The primary objective of this approach was to increase the composition of native grasses and forbs on native, unbroken sod while minimizing costs. The alternative management actions that were used to meet this objective include grazing, burning, burning and grazing, and rest (no action). A major challenge for FWS resource managers participating in the NPAM initiative was the recognition that other taxa, besides native grasses and forbs, may be affected by the alternative management practices, thus complicating the adaptive-management cycle and deepening the uncertainty. Specifically, many grassland birds are sensitive to changes in vegetation composition and structure, and thus management that alters vegetation also may affect bird populations. The primary objectives of this study were to assess the effects of alternative management actions on grassland birds on FWS-owned grasslands that are managed under the adaptive-management framework, and to assess the association of vegetation structure and composition as mechanisms for triggering grassland bird responses to management. We surveyed breeding birds and sampled vegetation on 89 native prairie NPAM units managed by the FWS during 2011–13, including 55 units in 2011, 87 units in 2012, and 87 units in 2013. The NPAM units were in 19 FWS refuge complexes and wetland management districts, including 14 complexes in FWS Region 6 (North Dakota, South Dakota, and Montana) and 5 complexes in FWS Region 3 (Minnesota). Generalized linear mixed models were used to evaluate the effects of management actions on vegetation structure, vegetation composition, and densities of common bird species. Vegetation structure and composition varied among study units and years, and many of these differences were linked to specific management activities or to the recency of those activities. We recorded 110 bird species in the 89 adaptive-management units. Models of bird abundance reflected not only disturbance-derived changes in vegetation structure and species-specific vegetation preferences but also the influence of defoliation treatments. Vegetation composition was less important to grassland birds than vegetation structure; in particular, mean vertical obstruction (vegetation height-density), bare-ground cover, and litter depth positively or negatively influenced densities of some grassland bird species. The diversity of bird responses to management in this study underscores the complexity of natural grassland systems and the need for heterogeneity management in grasslands in this region.

Minnesota, Montana, North Dakota, South Dakota↗