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At least 901 records · Page 50Linked to original sources
USGS2024

Life-history connections to long-term fish population trends in a species-rich temperate river

Fishes exhibit a diverse range of traits encompassing life-history strategies, feeding behaviours and spawning behaviours. These traits mediate fish population responses to changing environmental conditions such as those caused by anthropogenic stressors. The Conasauga River, located in northwestern Georgia and southeastern Tennessee, USA, hosts a diverse assemblage of over 75 species of freshwater fish, some of which are locally or regionally endemic, and many of which are imperilled. Annual monitoring data have shown population declines in multiple fish species of conservation concern in the Conasauga River since at least the 1990s, raising the possibility that other taxa could be declining as well. We quantified temporal changes in fish communities at six shoal sites sampled annually in most years from 1996 to 2022, and asked whether species traits hypothesized to underlie population vulnerability to environmental alteration were correlated with species-specific trends for 32 taxa. We estimated that total counts of fish in annual samples declined by ~2% per year, although declines were uneven among species and generally greater for less abundant taxa. Tests for species traits corresponding to temporal population trends provided evidence that crevice-spawning minnows and smaller-bodied taxa had steeper declines compared with broadcast spawners and larger, longer-lived, more fecund taxa. Lower abundance, reliance on a particular habitat feature, and life-history traits that may limit population resilience to disturbance may all prove useful for identifying riverine fishes at particular risk of future population decline.

Georgia↗
USGS2008

Water-Quality Data Collected from Vallecito Reservoir, Its Inflows and Outflow, Southwestern Colorado, 1999-2002

The Pine River Watershed Stakeholders Group was created in December 1997 to allow local participation in addressing water-quality issues in Los Pi?os River watershed, including Vallecito Reservoir in southwestern Colorado. One water-quality issue identified by the stakeholder group is to increase the understanding of the current water quality of Vallecito Reservoir, its two major inflows, and its outflow. The U.S. Geological Survey (USGS), in cooperation with volunteers from the Pine River Watershed Stakeholders Group and the U.S. Environmental Protection Agency (USEPA), U.S. Bureau of Reclamation (BOR), Colorado Department of Public Health and Environment (CDPHE), Pine River Irrigation District, Southern Ute Tribe, San Juan Basin Health Department, and San Juan Resource Conservation and Development, collected water-quality samples from Vallecito Reservoir, its two major inflows, and its outflow between August 1999 and November 2002 at about monthly intervals from April through November. The water-quality samples were analyzed for total and dissolved metals (aluminum, arsenic, cadmium, copper, chromium, iron, lead, manganese, mercury, nickel, silver, and zinc), dissolved major ions (calcium, magnesium, sodium, potassium, chloride, bicarbonate, and sulfate), dissolved silica, dissolved organic carbon (DOC), ultraviolet (UV) absorbance at 254 and 280 nanometers, nutrients (total organic nitrogen, dissolved organic nitrogen, dissolved ammonia, dissolved nitrate, total phosphorus, dissolved phosphorus, and orthophosphate), chlorophyll-a (reservoir only), and suspended sediment (inlets to the reservoir only). Measurements of field properties (pH, specific conductance, water temperature, and dissolved oxygen) were also made at each sampling site each time a water-quality sample was collected. This report documents (1) sampling sites and times of sample collection, (2) sample-collection methods, (3) laboratory analytical methods, and (4) responsibilities of each agency/group involved in the project. The report also provides the environmental and quality-control data collected during the project and provides an interpretation of the quality-control data (field blanks and field duplicates) to assess the quality of the environmental data. This report provides a baseline data set against which future changes in water quality can be assessed.

Data Series↗
USGS2018

Hydrologic and water-quality characteristics of Caño Boquerón, Cabo Rojo, and Puerto Mosquito, Isla de Vieques, Puerto Rico, July 2015–July 2016

Coastal lagoons are common features of the Puerto Rico shoreline that provide habitat for commercial and recreational species and serve important roles in the nutrient cycle of the ecosystems. The U.S. Geological Survey, in cooperation with the Puerto Rico Environmental Quality Board, conducted a limnological study at Caño Boquerón in Cabo Rojo and at Puerto Mosquito on Isla de Vieques, Puerto Rico, to assess the principal mechanisms affecting the hydrology and water-quality characteristics of these coastal lagoons and provide baseline information to the regulatory agencies responsible for the management and conservation of these coastal waters and the preservation of their aquatic life. Field measurements and water samples were collected and processed during July 2015–July 2016 for analysis of physical, chemical, biological, and bacteriological characteristics. In addition, bathymetric surveys were made and sediment cores were collected in each lagoon to determine water volume and sediment deposition rate. Physicochemical properties assessed at Caño Boquerón indicated values were generally in compliance with Puerto Rico Environmental Quality Board standards; turbidity was occasionally slightly greater than the established standards, and dissolved oxygen concentration at bottom depths was lower than standards limits. Water transparency was evaluated through the Secchi disk method, and the average depth of disappearance was 1.0 meter (m) for Caño Boquerón and 1.9 m for Puerto Mosquito. Assessment of biological characteristics at both sites included primary productivity calculations as well as carbon production equivalents and monthly water sampling for bacteriological and nutrient analyses. For Caño Boquerón, gross plankton primary productivity averaged 3.38 grams of oxygen per cubic meter per day (gO 2 /m 3 -d); this value was computed as the sum of net phytoplankton primary productivity (0.74 gO 2 /m 3 -d) and plankton respiration (2.64 gO 2 /m 3 -d). Net community primary productivity averaged 1.44 gO 2 /m 3 -d, and the community respiration rate averaged 8.10 gO 2 /m 3 -d, which indicates that the biological community, aside from phytoplankton, acts as a net consumer rather than a net producer of biomass. In Puerto Mosquito, gross plankton primary productivity averaged 2.07 gO 2 /m 3 -d, of which 0.39 gO 2 /m 3 -d could be ascribed to net phytoplankton primary productivity, and 1.68 gO 2 /m 3 -d could be ascribed to plankton respiration. Diel studies conducted at Puerto Mosquito reflected an average net community primary productivity of 2.43 gO 2 /m 3 -d, and the average respiration rate was 6.72 gO 2 /m 3 -d. In a bathymetric survey conducted in August 2015, the water volume for the Caño Boquerón lagoon was calculated as 967,000 cubic meters (m 3 ), and the water volume at Puerto Mosquito was calculated as 1,182,200 m 3 , with an average depth of 1.5 m for Caño Boquerón and 1.8 m for Puerto Mosquito. The daily seawater exchange for Caño Boquerón and Puerto Mosquito was 13 and 5 percent of their water volumes referenced to mean sea level, respectively. A total of 20 sediment samples were processed and analyzed for cesium-137 ( 137 Cs) and lead-210 ( 210 Pb) radioisotopes. Analyses indicated that the sediment deposition rate at Caño Boquerón ranged from 0.32 to 0.36 centimeter per year, based on age dating analysis of 137 Cs and 210 Pb data; in Puerto Mosquito, the sediment deposition rate ranged from 0.26 to 0.27 centimeter per year, based on 137 Cs and 210 Pb data. Bacteriological analyses at Caño Boquerón and Puerto Mosquito indicated that fecal coliform and enterococci concentrations were below Puerto Rico Environmental Quality Board standards during the study. The highest concentrations of fecal coliform (22 colonies per 100 milliliters) and enterococci (9 colonies per 100 milliliters) at Caño Boquerón occurred in July, which coincided with the busiest season of vacation rentals near the lagoon. Bacteria concentrations were generally lower in Puerto Mosquito than in Caño Boquerón; maximum concentrations of fecal coliform and enterococci bacteria were measured in November 2015. The potential sources of contamination for Puerto Mosquito are limited, because it is within a conservation area.

Caño Boquerón, Cabo Rojo, Puerto Mosquito, Isla de↗
USGS2024

Using life history traits to assess climate change vulnerability in understudied species

Climate change is a primary threat to biodiversity, but for many species, we still lack information required to assess their relative vulnerability to changes. Climate change vulnerability assessment (CCVA) is a widely used technique to rank relative vulnerability to climate change based on species characteristics, such as their distributions, habitat associations, environmental tolerances, and life-history traits. However, for species that we expect are vulnerable to climate change yet are understudied, like many amphibians, we often lack information required to construct CCVAs using existing methods. We used the CCVA framework to construct trait-based models based on life history theory, using empirical evidence of traits and distributions that reflected sensitivity of amphibians to environmental perturbation. We performed CCVAs for amphibians in 7 states in the north-central USA, focusing on 31 aquatic-breeding species listed as species of greatest conservation need by at least 1 state. Because detailed information on habitat requirements is unavailable for most amphibian species, we used species distributions and information on traits expected to influence vulnerability to a drying climate (e.g., clutch size and habitat breadth). We scored species vulnerability based on changes projected for mid-century (2040−2069) from 2 climate models representing “least-dry” and “most-dry” scenarios for the region. Species characteristics useful for discriminating vulnerability in our models included small range size, small clutch size, inflexible diel activity patterns, and smaller habitat breadth. When projected climate scenarios included a mix of drier and wetter conditions in the future, the exposure of a species to drying conditions was most important to relative rankings. When the scenario was universally drier, species characteristics were more important to relative rankings. Using information typically available even for understudied species and a range of climate projections, our results highlight the potential of using life history traits as indicators of relative climate vulnerability. The commonalities we identified provide a framework that can be used to assess other understudied species threatened by climate change.

Colorado, Kansas, Montana, Nebraska, North Dakota,↗
USGS2006

Temporal, spatial, and environmental influences on the demographics of grizzly bears in the Greater Yellowstone Ecosystem

During the past 2 decades, the grizzly bear ( Ursus arctos ) population in the Greater Yellowstone Ecosystem (GYE) has increased in numbers and expanded in range. Understanding temporal, environmental, and spatial variables responsible for this change is useful in evaluating what likely influenced grizzly bear demographics in the GYE and where future management efforts might benefit conservation and management. We used recent data from radio-marked bears to estimate reproduction (1983–2002) and survival (1983–2001); these we combined into models to evaluate demographic vigor (lambda [λ]). We explored the influence of an array of individual, temporal, and spatial covariates on demographic vigor.

Idaho, Montana, Wyoming↗
USGS2015

Broad-scale assessments of ecological landscapes: developing methods and applications

The U.S. Department of the Interior (DOI) Bureau of Land Management (BLM) is developing a Landscape Approach for managing multiple uses of public lands by incorporating multiscale information to quantify the effects of natural and human influences on natural resource conditions and trends. A primary goal of the approach is to identify opportunities for resource conservation, restoration, and development. The BLM Landscape Approach is developing assessment methods that promote consistency in management decisions, identify ecological characteristics that promote ecosystem resilience under rapidly changing environmental conditions, and foster collaboration among land management agencies. The BLM Landscape Approach is closely aligned with the DOI’s “A Strategy for Improving the Mitigation Policies and Practices of The Department of the Interior.” A major component of the BLM Landscape Approach is the Rapid Ecoregional Assessment (REA) program. REAs identify important ecosystems and wildlife habitats at broad spatial scales and determine where these resources are at risk from environmental stressors that can affect the integrity of ecological systems. Building on the lessons learned from completed or current REAs, the BLM, in partnership with the U.S. Geological Survey, will perform systematic comparisons of REA methods to identify the most promising suite of landscape-level analysis tools. In addition, the BLM and USGS will develop practical applications that demonstrate how to incorporate assessment information to address existing management issues, such as cumulative effects of proposed management actions. The outcome of these efforts will be a set of comprehensive technical guidance documents for conducting and applying broad-scale assessments.

Fact Sheet↗
USGS2026

Riverscape heterogeneity shapes population diversity for a migratory fish

Habitat patch dynamics can scale up to influence population demography and diversity with implications for resilience to environmental stochasticity. But how the spatial arrangement and size of habitat patches interact with other components of habitat heterogeneity to shape population diversity at larger spatial scales is not well understood. For riverine fishes, there is increasing evidence that tributary streams provide critical demographic support to main stem rivers. However, the extent to which main stem rivers rely on demographic contributions from tributaries, and the factors underlying this dependence, have not been assessed. Here, we used genetic stock identification to evaluate the effect of tributaries on population diversity of Yellowstone cutthroat trout ( Oncorhynchus virginalis bouvieri ) occupying the main stem Snake River, Wyoming, USA. We found that the main stem relied almost entirely on tributaries for demographic support, but main stem composition varied spatially among river sections. Distance between habitat patches, catchment area, and groundwater availability acted in concert to determine the contribution of specific tributaries to the main stem, but contributions were ultimately modulated by habitat connectivity. We also found evidence for multi-scale spatial structure in tributary contributions, providing insight into untested drivers of main stem river population diversity. Our results demonstrate how spatially discrete and distributed riverscape attributes influence population diversity at broader spatial scales, illustrating how ecosystem resilience emerges from the dynamic, two-way exchange of individuals and energy across habitat networks. Management plans for large rivers that address the ecological contributions of tributaries may be needed to achieve optimal outcomes. Similarly, conservation strategies that exclusively focus on headwater streams may fail to capture the broader habitat requirements necessary to maintain robust cold-water fish populations and associated recreational fisheries, particularly under global environmental change.

Wyoming↗
USGS2018

Landscape structure and temporal dynamic effects on Wintering Mallard abundance and distributions in the Mississippi alluvial valley

Context Management of wintering waterfowl in North America requires adaptability because constant landscape and environmental change challenges existing management strategies regarding waterfowl habitat use at large spatial scales. Migratory waterfowl including mallards (Anas platyrhynchos) use the lower Mississippi Alluvial Valley (MAV) for wintering habitat, making this an important area of emphasis for improving wetland conservation strategies, while enhancing the understanding of landscape-use patterns. Objectives We used aerial survey data collected in the Arkansas portion of the MAV (ARMAV) to explain the abundance and distribution of mallards in relation to variable landscape conditions. Methods We used two-stage, hierarchical spatio-temporal models with a random spatial effect to identify covariates related to changes in mallard abundance and distribution within and among years. Results We found distinct spatio-temporal patterns existed for mallard distributions across the ARMAV and these distributions are dependent on the surrounding landscape structure and changing environmental conditions. Models performing best indicated seasonal surface water extent, rice field, wetland and fallow (uncultivated) field abundance positively influenced mallard distribution. Rice fields, surface water and weather were found to influence mallard abundance. Additionally, are results suggest weather and changing surface water affects mallard presence and abundance throughout the winter, because the probability of mallard presence and abundance changed from the northern ARMAV in November to the southern ARMAV in January. Conclusions Using novel datasets to identify which environmental factors drive changes in regional wildlife distribution and abundance can improve management by providing managers additional information to manage land over landscapes spanning private and public lands. We suggest our analytical approach may be informative in other areas and for other wildlife species.

Arkansas↗
USGS2005

Chronic toxicity of un-ionized ammonia to early life-stages of endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus) compared to the surrogate fathead minnow (Pimephales promelas)

Ammonia-contaminated groundwater enters the Upper Colorado River from beneath the abandoned Moab Uranium Mill Tailings Pile near Moab, Utah. This reach of the Upper Colorado River was designated as critical habitat for four endangered fish species because it is one of the few existing areas with known spawning and rearing habitats. Un-ionized ammonia (NH3) concentrations frequently exceed 1.00 mg/L in backwaters adjacent to the tailings pile, which exceeds the Utah 30-d average chronic water quality criterion for un-ionized ammonia (0.07 mg/L NH3; temperature 20??C; pH 8.2) by a factor of more than 10. However, there is little published information regarding the sensitivity of endangered fishes to ammonia. We conducted 28-d static renewal studies with post-swim-up larvae to determine the relative sensitivity of Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), and the standard surrogate fathead minnow (Pimephales promelas) to NH3. Chronic values (ChVs) for mortality and growth were determined as the geometric mean of the no observed effect concentration and the lowest observed effect concentration based on analysis of variance. The ChVs for growth of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.40, and 0.67 mg/L NH3, respectively. The ChVs for mortality of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.70, and 0.67 mg/L NH3, respectively. Therefore, the ChVs for mortality and growth were similar for fathead minnow and razorback sucker; however, the ChV for growth was lower than the ChV for mortality for Colorado pikeminnow. Maximum likelihood regression was used to calculate 28-d lethal concentrations (LCx) for each species. The 28-d LC50, LC20, and LC1 values for fathead minnow were 0.69, 0.42, and 0.13 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for Colorado pikeminnow were 0.76, 0.61, and 0.38 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for razorback sucker were 0.54, 0.38, and 0.25 mg/L NH3, respectively. The fathead minnow, Colorado pikeminnow, and razorback sucker are relatively similar in sensitivity and rank at the 35th, 49th, and 31st percentiles, respectively, of the theoretical chronic fish sensitivity distributions for NH3. The existing water quality criteria for NH3, if met by remediation activities at the Moab site, would be protective of these endangered fishes even if fish sensitivity is based on the conservative LC1 value. ?? 2005 Springer Science+Business Media, Inc.

Archives of Environmental Contamination and Toxico↗
USGS2005

Effects of biotic and abiotic factors on the distribution of trout and salmon along a longitudinal stream gradient

We examined the influence of biotic and abiotic factors on the distribution, abundance, and condition of salmonid fishes along a stream gradient. We observed a longitudinal change in fish distribution with native cutthroat trout, Oncorhynchus clarki utah, and introduced brown trout, Salmo trutta, demonstrating a distinct pattern of allopatry. Cutthroat trout dominated high elevation reaches, while reaches at lower elevations were dominated by brown trout. A transition zone between these populations was associated with lower total trout abundance, consistent changes in temperature and discharge, and differences in dietary preference. Variation in cutthroat trout abundance was best explained by a model including the abundance of brown trout and diel temperature, whereas variation in brown trout abundance was best explained by a model including the abundance of cutthroat trout and discharge. These results suggest the potential for condition-mediated competition between the two species. The results from our study can aid biologists in prioritizing conservation activities and in developing robust management strategies for cutthroat trout. ?? Springer 2005.

Environmental Biology of Fishes↗
USGS2016

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

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

Journal of Environmental Management↗
USGS2010

Evaluating the behavior of gadolinium and other rare earth elements through large metropolitan sewage treatment plants

A primary pathway for emerging contaminants (pharmaceuticals, personal care products, steroids, and hormones) to enter aquatic ecosystems is effluent from sewage treatment plants (STP), and identifying technologies to minimize the amount of these contaminants released is important. Quantifying the flux of these contaminants through STPs is difficult. This study evaluates the behavior of gadolinium, a rare earth element (REE) utilized as a contrasting agent in magnetic resonance imaging (MRI), through four full-scale metropolitan STPs that utilize several biosolids thickening, conditioning, stabilization, and dewatering processing technologies. The organically complexed Gd from MRIs has been shown to be stable in aquatic systems and has the potential to be utilized as a conservative tracer in STP operations to compare to an emerging contaminant of interest. Influent and effluent waters display large enrichments in Gd compared to other REEs. In contrast, most sludge samples from the STPs do not display Gd enrichments, including primary sludges and end-product sludges. The excess Gd appears to remain in the liquid phase throughout the STP operations, but detailed quantification of the input Gd load and residence times of various STP operations is needed to utilize Gd as a conservative tracer.

Environmental Science & Technology↗
USGS2004

Evaluating microbial purification during soil treatment of wastewater with multicomponent tracer and surrogate tests

Soil treatment of wastewater has the potential to achieve high purification efficiency, yet the understanding and predictability of purification with respect to removal of viruses and other pathogens is limited. Research has been completed to quantify the removal of virus and bacteria through the use of microbial surrogates and conservative tracers during controlled experiments with three-dimensional pilot-scale soil treatment systems in the laboratory and during the testing of full-scale systems under field conditions. The surrogates and tracers employed included two viruses (MS-2 and PRID-1 bacteriophages), one bacterium (ice-nucleating active Pseudomonas ), and one conservative tracer (bromide ion). Efforts have also been made to determine the relationship between viruses and fecal coliform bacteria in soil samples below the wastewater infiltrative surface, and the correlation between Escherichia coli concentrations measured in percolating soil solution as compared with those estimated from analyses of soil solids. The results suggest episodic breakthrough of virus and bacteria during soil treatment of wastewater and a 2 to 3 log (99-99.9%) removal of virus and near complete removal of fecal coliform bacteria during unsaturated flow through 60 to 90 cm of sandy medium. Results also suggest that the fate of fecal coliform bacteria may be indicative of that of viruses in soil media near the infiltrative surface receiving wastewater effluent. Concentrations of fecal coliform in percolating soil solution may be conservatively estimated from analysis of extracted soil solids.

Journal of Environmental Quality↗
USGS2022

Reassessing perennial cover as a driver of duck nest survival in the Prairie Pothole Region

Conservation plans designed to sustain North American duck populations prominently feature a key hypothesis stating that the amount of the landscape in perennial cover surrounding upland duck nests positively influences nest survival rates. Recent conflicting research testing this hypothesis creates ambiguity regarding which management actions to pursue and where to prioritize conservation delivery. We compared existing models and new formulations of existing models explaining spatiotemporal variation in nest survival using independent data documenting the fate of >20,000 duck nests within the Drift Prairie, Missouri Coteau, and Prairie Coteau physiographic regions of the United States Prairie Pothole Region during 2002–2018. Our results suggest an inconsistent relationship between perennial cover and survival of upland duck nests, which depended upon physiographic region and current and time-lagged landscape and environmental conditions. The magnitude and direction of how perennial cover correlated with daily nest survival depended on its dominance as a landcover type. A positive relationship existed when perennial cover was a minor component of landcover in all physiographic regions (<30% of a 10.4-km 2 area) and, in the Drift Prairie and Prairie Coteau, when perennial cover was the dominant landcover type (>60%). A constant or negative relationship was predicted at locations of about 30–60% perennial cover. Additionally, environmental conditions (i.e., density of wetlands and estimated gross primary productivity in the previous year) moderated or enhanced the effect of perennial cover on nest survival, depending on physiographic region. Our finding of inconsistency in the relationship between perennial cover and nest survival contradicts the conservation premise that nest survival universally increases linearly when uplands are converted to perennial cover. Promoting policies and management actions designed to increase perennial cover can be expected to be situationally but not consistently associated with higher survival of upland duck nests.

Montana, North Dakota, South Dakota↗
USGS2012

Mapping anuran habitat suitability to estimate effects of grassland and wetland conservation programs

The conversion of the Northern Great Plains of North America to a landscape favoring agricultural commodity production has negatively impacted wildlife habitats. To offset impacts, conservation programs have been implemented by the U.S. Department of Agriculture and other agencies to restore grassland and wetland habitat components. To evaluate effects of these efforts on anuran habitats, we used call survey data and environmental data in ecological niche factor analyses implemented through the program Biomapper to quantify habitat suitability for five anuran species within a 196 km 2 study area. Our amphibian call surveys identified Northern Leopard Frogs ( Lithobates pipiens ), Wood Frogs ( Lithobates sylvaticus ), Boreal Chorus Frogs ( Pseudacris maculata ), Great Plains Toads ( Anaxyrus cognatus ), and Woodhouse’s Toads ( Anaxyrus woodhousii ) occurring within the study area. Habitat suitability maps developed for each species revealed differing patterns of suitable habitat among species. The most significant findings of our mapping effort were 1) the influence of deep-water overwintering wetlands on suitable habitat for all species encountered except the Boreal Chorus Frog; 2) the lack of overlap between areas of core habitat for both the Northern Leopard Frog and Wood Frog compared to the core habitat for both toad species; and 3) the importance of conservation programs in providing grassland components of Northern Leopard Frog and Wood Frog habitat. The differences in habitats suitable for the five species we studied in the Northern Great Plains, i.e., their ecological niches, highlight the importance of utilizing an ecosystem based approach that considers the varying needs of multiple species in the development of amphibian conservation and management plans.

Copeia↗
USGS2020

Using NASA Earth observations and Google Earth Engine to map winter cover crop conservation performance in the Chesapeake Bay watershed

Winter cover crops such as barley, rye, and wheat help to improve soil structure by increasing porosity, aggregate stability, and organic matter, while reducing the loss of agricultural nutrients and sediments into waterways. The environmental performance of cover crops is affected by choice of species, planting date, planting method, nutrient inputs, temperature, and precipitation. The Maryland Department of Agriculture (MDA) oversees an agricultural cost-share program that provides farmers with funding to cover costs associated with planting winter cover crops, and the U.S. Geological Survey (USGS) and the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) have partnered with the MDA to develop satellite remote sensing techniques for measuring cover crop performance. The MDA has developed the capacity to digitize field boundaries for all fields enrolled in their cover crop programs (>26,000 fields per year) to support a remote sensing performance analysis at a statewide scal,e and has requested assistance with the associated imagery processing from the National Aeronautics and Space Administration (NASA). Using the Google Earth Engine (GEE) cloud computing platform, scripts were developed to process Landsat 5/7/8 and Harmonized Sentinel-2 imagery to measure winter cover crop performance. We calibrated cover crop performance models using linear regression between satellite vegetation indices and USGS / USDA-ARS field sampling data collected on Maryland farms between 2006 and 2012 (1298 samples). Satellite-derived Normalized Difference Vegetation Index (NDVI) values showed significant correlation with the natural logarithm of cover crop biomass ( p ≤0.01, R 2 = 0.56) and with observed percent vegetative ground cover (p ≤0.01, R 2 = 0.68). The GEE scripts were used to composite seasonal maximum NDVI values for each enrolled cover crop field and calculate performance metrics for the winter and spring seasons of three enrollment years (2014–15, 2015–16, and 2017–18) for four Maryland counties. Results from winter 2017–18 demonstrate that rye and barley fields had higher biomass than wheat fields, and that early planting, along with planting methods that increase seed-soil contact, increased performance. The processing capabilities of GEE will support the MDA in scaling up remote sensing performance analysis statewide, providing information to evaluate the environmental outcomes associated with various agronomic management strategies. The tool can be modified for different seasonal cutoffs, utilize new sensors to capture phenology in winter and spring, and scale to larger regions for use in adaptive management of winter cover crops planted for environmental benefit.

Maryland↗
USGS2013

Rejoinder: Challenge and opportunity in the study of ungulate migration amid environmental change

Increasingly, animals that migrate long distances to exploit seasonal habitats must traverse political boundaries capable of altering the very ecological gradients that promote migratory behavior. This transboundary aspect of migration presents many new challenges and opportunities for research and conservation (e.g., Bolger et al. 2008, Taillon et al. 2012). Work to date has often focused on physical barriers to movement (roads, fences,and housing and energy development) that can threaten migratory populations to varying degrees (Holdo et al. 2011, Sawyer et al. 2013). However, even in the absence of conspicuous barriers, political and jurisdictional boundaries can bring dramatic differences in land use and conservation policy. What happens to migratory populations when these boundaries alter the resources and refuges that they seek on their seasonal journeys?

Ecology↗
USGS2022

Site fidelity as a maladaptive behavior in the Anthropocene

Site fidelity, or the behavior of returning to previously visited locations, has been observed across taxa and ecosystems. By developing familiarity with a particular location, site fidelity provides a range of benefits and is advantageous in stable or predictable environments. However, the Anthropocene is characterized by rates of environmental change that outpace the evolutionary history of extant taxa, which can result in site fidelity becoming maladaptive. Here we outline the theoretical underpinnings for maladaptive site fidelity and synthesize empirical research supporting its occurrence, and examine it in the context of a related concept, ecological traps, whereby organisms exhibit maladaptive behavior in habitat selection. We then discuss adaptive mechanisms that may enable species with site fidelity to continue to persist in the Anthropocene. With ongoing environmental change, researchers and practitioners should expect fidelity-induced ecological traps to become more common, and initiate projects to identify and understand their origins. Such knowledge will help conserve the widespread and ecologically important behavior of site fidelity.

Frontiers in Ecology and the Environment↗