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At least 955 records · Page 53Linked to original sources
USGS2023

Integrated analysis shows how the effects of extreme flooding events propagate through fish communities to impact amphibians

Research Highlight: Davis, C. L., Walls, S. C., Barichivich, W. J., Brown, M. E., & Miller, D. A. (2022). Disentangling direct and indirect effects of extreme events on coastal wetland communities. Journal of Animal Ecology , https://doi.org/10.1111/1365-2656.13874 . Catastrophic events such as floods, hurricanes, winter storms, droughts and wildfires increasingly touch our lives either directly or indirectly. These events draw our attention to the seriousness of changes in climate not only to human well-being but also to the integrity of ecological systems upon which we depend. Understanding the impacts of extreme events on ecological systems requires the ability to characterize the cascading effects of environmental changes on the environments in which organisms live and the altered biological interactions produced. This scientific ambition represents no small challenge for the study of animal communities, which are typically difficult to census as well as dynamic in time and space. Davis et al. (2022) in a recent study in the Journal of Animal Ecology examined the amphibian and fish communities found in depressional coastal wetlands to better understand how they respond to major rainfall and flooding events. Data from the U.S. Geological Survey's Amphibian Research and Monitoring Initiative provided an 8-year record of observations as well as environmental measurements. For this study, the authors integrated techniques for assessing the dynamics of animal populations with a Bayesian implementation of structural equation modelling. Using their integrated methodological approach permitted the authors to reveal the direct and indirect effects of extreme weather events on co-occurring amphibian and fish communities while accounting for observational uncertainty and temporal variation in population-level processes. Their findings indicate that the most prominent effects of flooding on the amphibian community were caused by changes in the fish community that led to increased predation and resource competition. In their conclusions, the authors emphasize the importance of understanding networks of abiotic and biotic effects if we are to predict and mitigate the influence of extreme weather events.

Journal of Animal Ecology↗
USGS2013

Community food webs

Community food webs describe the feeding relationships, or trophic interactions, between the species of an ecological community. Both the structure and dynamics of such webs are the focus of food web research. The topological structures of empirical food webs from many ecosystems have been published on the basis of field studies and they form the foundation for theory concerning the mean number of trophic levels, the mean number of trophic connections versus number of species, and other food web measures, which show consistency across different ecosystems. The dynamics of food webs are influenced by indirect interactions, in which changes in the level of a population in one part of the food web may have indirect effects throughout the web. The mechanisms of these interactions are typically studied microcosm experiments, or sometimes in-field experiments. The use of mathematical models is also a major approach to understanding the effects of indirect interactions. Both empirical and mathematical studies have revealed important properties of food webs, such as keystone predators and trophic cascades.

Book chapter↗
USGS2024

The use of conceptual ecological models to identify critical data and uncertainties to support numerical modeling: The northern Gulf of Mexico eastern oyster Crassostrea virginica example

Objective Increasing reliance on numerical simulation models to help inform management and restoration choices benefits from careful consideration of critical early steps in model development. Along the northern coast of the Gulf of Mexico, the eastern oyster Crassostrea virginica fulfills important ecological and economic roles. Using the eastern oyster as an example, we draw on several recent frameworks outlining best practices for model development and application for restoration, conservation, and management. Methods We identify priority model questions, outline a conceptual ecological model (CEM) to guide numerical model development, and use this framework to identify uncertainties and research needs. Result The CEM uses a nested design, identifying explicit vital rates, processes, attributes, and outcomes for the species (oysters), population, and metapopulation (i.e., network of populations) levels in response to drivers of species, population, and metapopulation changes and changing environmental factors. Most management actions related to oyster restoration and harvest affect population attributes directly, but many coastal management actions and changes (i.e., climate change and coastal and water resource engineering) impact environmental factors that alter vital rates and attributes of oysters, populations, and metapopulations. Conclusion Investment in studies targeting individual oyster‐ and population‐level multi‐stressor responses (filtration, respiration, growth, and reproduction) and improving hydrodynamic and environmental models targeting drivers that influence metapopulation vital rates and attributes (i.e., connectivity and substrate persistence) would contribute to reducing uncertainties. Development of numerical models covering the entire oyster life cycle and connectivity of populations using hydrodynamic models of current and predicted conditions to provide key abiotic and biotic factors influencing larval movement, recruitment, and on‐reef oyster vital rates would assist in balancing the goals of conservation, restoration, and fisheries management of this foundational estuarine species.

Marine and Coastal Fisheries: Dynamics, Management↗
USGS2014

Impacts of drought and crayfish invasion on stream ecosystem structure and function

Drought and seasonal drying can be important disturbance events in many small streams, leading to intermittent or isolated habitats. Many small streams contain crayfish populations that are often keystone or dominant species in these systems. I conducted an experiment in stream mesocosms to examine the effects of drought and potential ecological redundancy of a native and invasive crayfish species. I examined the effects of drought (drought or control) and crayfish presence (none, native crayfish Orconectes eupunctus or invasive crayfish Orconectes neglectus ) on stream mesocosm structure and function (leaf breakdown, community metabolism, periphyton, sediment and chironomid densities) in a fully factorial design. Each mesocosm contained a deep and shallow section, and drought treatments had surface water present (5-cm depth) in deep sections where tiles and leaf packs were placed. Drought and crayfish presence did not interact for any response variable. Drought significantly reduced leaf breakdown, and crayfish presence significantly increased leaf breakdown. However, the native and invasive crayfish species did not differ significantly in their effects on leaf breakdown. Drought significantly reduced primary production and community respiration overall, whereas crayfish presence did not significantly affect primary production and community respiration. Neither drought nor crayfish presence significantly affected periphyton overall. However, drought significantly reduced autotrophic index (AI), and crayfish presence increased AI. Inorganic sediment and chironomid density were not affected by drought, but both were significantly reduced by crayfish presence. O. eupunctus reduced AI and sediment more than O. neglectus did. Neither drought nor crayfish species significantly affected crayfish growth or survival. Drought can have strong effects on ecosystem function, but weaker effects on benthic structure. Crayfish can have strong effects on ecosystem structure and function regardless of drought. In stream mesocosms, native and invasive crayfish species appeared largely ecologically redundant, although subtle differences in crayfish effects could cascade throughout the food web, and further research is needed to address this question.

River Research and Applications↗
USGS2017

The state of the world’s mangroves in the 21st century under climate change

Concerted mangrove research and rehabilitation efforts over the last several decades have prompted a better understanding of the important ecosystem attributes worthy of protection and a better conservation ethic toward mangrove wetlands globally. While mangroves continue to be degraded and lost in specific regions, conservation initiatives, rehabilitation efforts, natural regeneration, and climate range expansion have promoted gains in other areas, ultimately serving to curb the high mangrove habitat loss statistics from the doom and gloom of the 1980s. We highlight those trends in this article and introduce this special issue of Hydrobiologia dedicated to the important and recurring Mangrove and Macrobenthos Meeting. This collection of papers represents studies presented at the fourth such meeting (MMM4) held in St. Augustine, Florida, USA, on July 18–22, 2016. Our intent is to provide a balanced message about the global state of mangrove wetlands by describing recent reductions in net mangrove area losses and highlighting primary research studies presented at MMM4 through a collection of papers. These papers serve not only to highlight on-going global research advancements, but also provide an overview of the vast amount of data on mangrove ecosystem ecology, biology and rehabilitation that emphasizes the uniqueness of the mangrove community.

Hydrobiologia↗
USGS2015

Icefield-to-ocean linkages across the northern Pacific coastal temperate rainforest ecosystem

Rates of glacier mass loss in the northern Pacific coastal temperate rainforest (PCTR) are among the highest on Earth, and changes in glacier volume and extent will affect the flow regime and chemistry of coastal rivers, as well as the nearshore marine ecosystem of the Gulf of Alaska. Here we synthesize physical, chemical and biological linkages that characterize the northern PCTR ecosystem, with particular emphasis on the potential impacts of glacier change in the coastal mountain ranges on the surface–water hydrology, biogeochemistry, coastal oceanography and aquatic ecology. We also evaluate the relative importance and interplay between interannual variability and long-term trends in key physical drivers and ecological responses. To advance our knowledge of the northern PCTR, we advocate for cross-disciplinary research bridging the icefield-to-ocean ecosystem that can be paired with long-term scientific records and designed to inform decisionmakers.

Pacific coastal temperate rainforest↗
USGS2023

A review of lethal thermal tolerance among freshwater mussels (Bivalvia: Unionida) within the North American faunal region

Freshwater mussels of the order Unionida are currently one of the most imperiled groups of organisms in the North American faunal region. Accurate risk assessments and development of effective management strategies for remaining populations require knowledge of thermal limits in the face of increasing surface water temperature due to climate change and various anthropogenic factors. We conducted a systematic literature review of unionid mussels (order Unionida, families Margaritiferidae and Unionidae) in the North American faunal region to (1) summarize lethal thermal tolerance data by life stage and taxonomy, (2) discuss ecological and climate change implications of existing lethal tolerance data, and (3) identify needs for future research. We identified lethal tolerance estimates for only 28 of 302 species in the families Unionidae and Margaritiferidae. The mean acute median lethal temperatures were 32.8 °C for glochidia (19 species), 35.0 °C for juveniles (13 species), and 36.3 °C for adults (4 species). Generally, glochidia were less tolerant than juveniles or adults of the same species—but there were several exceptions. Generally, Amblemini had the highest acute and chronic thermal tolerance of all tribes followed by Anodontini, Pleurobemini, Lampsilini, and Quadrilini. Acclimation temperature affected lethal tolerance endpoints in less than half (52 of 145) of comparisons within species. Lethal tolerance data for additional species, combined with a comprehensive database of in situ surface water temperatures, would be useful for modeling the frequency and duration of lethal limit exceedance in North America and identifying populations currently living at or near their upper lethal limits.

Environmental Reviews↗
USGS2024

Seabed maps showing topography, ruggedness, backscatter intensity, sediment mobility, and the distribution of geologic substrates in quadrangle 5 of the Stellwagen Bank National Marine Sanctuary region offshore of Boston, Massachusetts

The U.S. Geological Survey, in cooperation with the National Marine Sanctuary Program of the National Oceanic and Atmospheric Administration, has conducted seabed mapping and related research in the Stellwagen Bank National Marine Sanctuary (SBNMS) region since 1993. The area being mapped using geophysical and geological data includes the SBNMS and the surrounding region, which totals approximately 3,700 square kilometers (km 2 ) and is subdivided into 18 quadrangles. The seabed is a glaciated terrain that is topographically and texturally diverse. Quadrangle 5, the subject of this scientific investigations map, has an area of 211 km 2 and has water depths that range from 23 meters (m) on the Stellwagen Bank crest to 105 m in the Stellwagen Basin. Seven map types, each at a scale of 1:25,000, depict seabed topography, ruggedness, backscatter intensity, distribution of geologic substrates, sediment mobility, distribution of fine- and coarse-grained sand, and substrate mud content. These maps show the distribution of geologic substrates on the crest and western flank of the south-central part of Stellwagen Bank and in Stellwagen Basin to the west. Interpretations of multibeam sonar bathymetric and seabed backscatter imagery, photographs, video imagery, and grain-size analyses were used to create the geology-based maps. Data from 729 stations were analyzed, including 620 sediment samples. The geologic substrate maps of quadrangle 5 show the distribution of 20 substrates that represent a wide range of textures, such as mobile and rippled sand, immobile sand, sand that partially veneers gravel, boulder ridges, and mud. Mapped substrates are characterized by sediment grain-size composition, surface morphology, substrate layering, the mobility or immobility of substrate surfaces, and water depth range. This scientific investigations map portrays the major geological elements (substrates, topographic features, and processes) of environments in quadrangle 5. It is intended to provide a foundation for research into present and past sediment transport processes in a complex terrain, provide insights into the ecological requirements of invertebrate and vertebrate species that utilize the various substrates, and to support seabed management in the region.

Massachusetts↗
USGS2024

Seabed maps showing topography, ruggedness, backscatter intensity, sediment mobility, and the distribution of geologic substrates in quadrangle 2 of the Stellwagen Bank National Marine Sanctuary region offshore of Boston, Massachusetts

The U.S. Geological Survey, in cooperation with the National Marine Sanctuary Program of the National Oceanic and Atmospheric Administration, has conducted seabed mapping and related research in the Stellwagen Bank National Marine Sanctuary (SBNMS) region since 1993. The area being mapped using geophysical and geological data includes the SBNMS and the surrounding region, which totals approximately 3,700 square kilometers (km 2 ) and is subdivided into 18 quadrangles. The seabed is a glaciated terrain that is topographically and texturally diverse. Quadrangle 2, the subject of this scientific investigations map, has a mapped area of 209 km 2 and has water depths that range from about 19 meters (m) on the Stellwagen Bank crest to about 68 m in the Stellwagen Basin. Seven map types, each at a scale of 1:25,000, depict seabed topography, ruggedness, backscatter intensity, distribution of geologic substrates, sediment mobility, distribution of fine- and coarse-grained sand, and substrate mud content. These maps show the distribution of geologic substrates across the southwestern part of Stellwagen Bank, in Stellwagen Basin to the west and southwest of the bank, and in Little Stellwagen Basin and the western part of Race Point Channel to the south of the bank. Interpretations of multibeam sonar bathymetric and seabed backscatter imagery, photographs, video imagery, and grain-size analyses were used to create the geology-based maps. Data from 733 stations were analyzed, including 656 sediment samples. The geologic substrate maps of quadrangle 2 show the distribution of 19 geologic substrates that represent a wide range of textures, such as rippled and immobile sand, immobile muddy sand and sandy mud, sand that partially veneers gravel, and a boulder ridge. Mapped substrates are characterized by sediment grain-size composition, surface morphology, substrate layering, the mobility or immobility of substrate surfaces, and water depth range. This scientific investigations map portrays the major geological elements (substrates, topographic features, and processes) of environments in quadrangle 2. It is intended to provide a foundation for research into present and past sediment transport processes in a complex terrain, provide insights into the ecological requirements of invertebrate and vertebrate species that utilize the various substrates, and support seabed management in the region.

Massachusetts↗
USGS2026

Seabed maps showing topography, ruggedness, backscatter intensity, sediment mobility, and the distribution of geologic substrates in quadrangle 3 of the Stellwagen Bank National Marine Sanctuary region offshore of Boston, Massachusetts

The U.S. Geological Survey, in cooperation with the National Marine Sanctuary Program of the National Oceanic and Atmospheric Administration, has conducted seabed mapping and related research in the Stellwagen Bank National Marine Sanctuary (SBNMS) region since 1993. The area being mapped using geophysical and geological data includes the SBNMS and the surrounding region, which totals approximately 3,700 square kilometers (km 2 ) and is subdivided into 18 quadrangles. The seabed is a glaciated terrain that is topographically and texturally diverse. Quadrangle 3, the subject of this scientific investigations map, has a mapped area of 185 km 2 and has water depths that range from about 30 meters (m) on the Stellwagen Bank crest to about 135 m in a basin east of South Ninety Bank, which lies off the eastern margin of Stellwagen Bank. Seven map types, each at a scale of 1:25,000, depict seabed topography, ruggedness, backscatter intensity, distribution of geologic substrates, sediment mobility, distribution of fine- and coarse-grained sand, and substrate mud content. These maps show the distribution of geologic substrates on the southeastern part of Stellwagen Bank, on adjacent banks and basins in deeper water to the east, in the eastern part of Race Point Channel to the south of the bank, and on the northern slope of Cape Cod. Interpretations of multibeam sonar bathymetric and seabed backscatter imagery, photographs, video imagery, and grain-size analyses were used to create the geology-based maps. Data from 309 stations were analyzed, including 279 sediment samples. The geologic substrate maps of quadrangle 3 show the distribution of 21 geologic substrates that represent a wide range of textures, such as rippled sand, immobile sand, immobile muddy sand, sand that partially veneers gravel, and boulder ridges. Mapped substrates are characterized by sediment grain-size composition, surface morphology, substrate layering, the mobility or immobility of substrate surfaces, and water depth range. This scientific investigations map portrays the major geological elements (substrates, topographic features, and processes) of environments in quadrangle 3. It is intended to provide a foundation for research into present and past sediment transport processes in a complex terrain, provide insights into the ecological requirements of invertebrate and vertebrate species that use the various substrates, and support seabed management in the region.

Quadrangle 3 of the Stellwagen Bank National Marin↗
USGS2007

Detection of viral hemorrhagic septicemia in round gobies in New York State (USA) waters of Lake Ontario and the St. Lawrence River

In May 2006 a large mortality of several thousand round gobies Neogobius melanostomus (Pallas, 1814) occurred in New York waters of the St. Lawrence River and Lake Ontario. Necropsies of sampled fish from these areas showed pallor of the liver and gills, and hemorrhagic areas in many organs. Histopathologic examination of affected tissues revealed areas of necrosis and hemorrhage. Inoculations of fathead minnow Pimephales promelas (Rafinesque, 1820) cell cultures with dilutions of tissue samples from the necropsied gobies produced a cytopathic effect within 5 d post-inoculation. Samples of cell culture supernatant were tested using RT-PCR and confirmed the presence of viral hemorrhagic septicemia virus (VHSV). Sequence analysis of the VHSV isolate resulted in its assignment to the type-IVb subgroup. The detection of VHSV in a relatively recent invasive fish species in the Great Lakes and the potential impact of VHSV on the ecology and economy of the area will require further investigation and careful management considerations. Inter-Research 2007.

New York↗
USGS2005

Decision making with environmental indices

Since Ott's seminal book on environmental indices (1978), the use of indices has expanded into several natural resource disciplines, including ecological studies, environmental policymaking, and agricultural economics. However, despite their increasing use in natural resource disciplines, researchers and public decision makers continue to express concern about validity of these instruments to capture and communicate multidimensional, and sometimes disparate, characteristics of research data and stakeholder interests. Our purpose is to demonstrate how useful indices can be for communicating environmental information to decision makers. We discuss how environmental indices have evolved over four stages: 1) simple; 2) compound multicriteria; 3) the impact matrix and 4) disparate stakeholder management. We provide examples of simple and compound indices that were used by policy decision makers. We then build a framework, called an Impact Matrix (IM), that comprehensively accounts for multiple indices but lets the user decide how to integrate them. The IM was shaped from the concept of a financial risk payoff matrix and applied to ecosystem risk. While the IM offers flexibility, it does not address stakeholder preferences about which index to use. Therefore, the last phase in our evolutionary ladder includes stakeholder indices to specifically address disparate stakeholder preferences. Finally, we assert that an environmental index has the potential to increase resource efficiency, since the number of decision making resources may be reduced, and hence improve upon resource productivity

Book chapter↗
USGS2025

Visioning and conceptual framework for coordinating Great Lakes connecting waters research and monitoring

The Laurentian Great Lakes are connected via naturally occurring straits and rivers: St. Marys River, Straits of Mackinac, St. Clair-Detroit River System, Niagara River, and the St. Lawrence River. Despite the historical ecological and economic importance of these waters, international agreements (e.g., Great Lakes Water Quality Agreement) only recently explicitly named the Great Lakes Connecting Waters (GLCWs), requiring governments to address the challenges of adequate restoration and protection from historical use and degradation. Standardized research and monitoring activities are needed; however, there is no established mechanism for coordination across the GLCWs. A three-day summit in 2023 convened experts to form the initial framework for a GLCWs Collaborative to increase standardizations and knowledge transfer. Participants drafted a governance structure and priorities following the principles of collective impact but allowed for place-based specificity for local connecting water organizations. Priorities and suggestions for success included: 1) co-development of the collaborative with all rights holders, stakeholders, and surrounding communities; 2) investment in research and technology specific to GLCWs; 3) investment in information transfer and training; 4) increased communication; and 5) better integration into existing Great Lakes research, monitoring, and funding programs. Expanding participation in all local GLCWs organizations with principles of inclusivity was identified as a larger collaborative goal. Next steps in the development of a GLCWs Collaborative include increased communication and formation of working groups and obtaining funding for a dedicated organization to begin supporting activities (communication, facilitation, logistics). By using a deliberate process for establishment, the potentially slower time frame for establishment may result in increased participation and success.

Laurentian Great Lakes↗
USGS2010

A proposed lexicon of terms and concepts for human-bear management in North America

We believe that communication within and among agency personnel in the United States and Canada about the successes and failures of their human–bear (Ursidae) management programs will increase the effectiveness of these programs and of bear research. To communicate more effectively, we suggest agencies clearly define terms and concepts used in human–bear management and use them in a consistent manner. We constructed a human–bear management lexicon of terms and concepts using a modified Delphi method to provide a resource that facilitates more effective communication among human–bear management agencies. Specifically, we defined 40 terms and concepts in human–bear management and suggest definitions based on discussions with 13 other professionals from the United States and Canada. Although new terms and concepts will emerge in the future and definitions will evolve as we learn more about bear behavior and ecology, our purpose is to suggest working definitions for terms and concepts to help guide human–bear management and research activities in North America. Applications or revisions of these definitions may be useful outside of North America.

Ursus↗
USGS2011

USGS research on Florida's isolated freshwater wetlands

The U.S. Geological Survey (USGS) has studied wetland hydrology and its effects on wetland health and ecology in Florida since the 1990s. USGS wetland studies in Florida and other parts of the Nation provide resource managers with tools to assess current conditions and regional trends in wetland resources. Wetland hydrologists in the USGS Florida Water Science Center (FLWSC) have completed a number of interdisciplinary studies assessing the hydrology, ecology, and water quality of wetlands. These studies have expanded the understanding of wetland hydrology, ecology, and related processes including: (1) the effects of cyclical changes in rainfall and the influence of evapotranspiration; (2) surface-water flow, infiltration, groundwater movement, and groundwater and surfacewater interactions; (3) the effects of water quality and soil type; (4) the unique biogeochemical components of wetlands required to maintain ecosystem functions; (5) the effects of land use and other human activities; (6) the influences of algae, plants, and invertebrates on environmental processes; and (7) the effects of seasonal variations in animal communities that inhabit or visit Florida wetlands and how wetland function responds to changes in the plant community.

Florida↗
USGS2015

Distance measures and optimization spaces in quantitative fatty acid signature analysis

Quantitative fatty acid signature analysis has become an important method of diet estimation in ecology, especially marine ecology. Controlled feeding trials to validate the method and estimate the calibration coefficients necessary to account for differential metabolism of individual fatty acids have been conducted with several species from diverse taxa. However, research into potential refinements of the estimation method has been limited. We compared the performance of the original method of estimating diet composition with that of five variants based on different combinations of distance measures and calibration-coefficient transformations between prey and predator fatty acid signature spaces. Fatty acid signatures of pseudopredators were constructed using known diet mixtures of two prey data sets previously used to estimate the diets of polar bears Ursus maritimus and gray seals Halichoerus grypus, and their diets were then estimated using all six variants. In addition, previously published diets of Chukchi Sea polar bears were re-estimated using all six methods. Our findings reveal that the selection of an estimation method can meaningfully influence estimates of diet composition. Among the pseudopredator results, which allowed evaluation of bias and precision, differences in estimator performance were rarely large, and no one estimator was universally preferred, although estimators based on the Aitchison distance measure tended to have modestly superior properties compared to estimators based on the Kullback-Leibler distance measure. However, greater differences were observed among estimated polar bear diets, most likely due to differential estimator sensitivity to assumption violations. Our results, particularly the polar bear example, suggest that additional research into estimator performance and model diagnostics is warranted.

Ecology and Evolution↗
USGS1983

Pack size and wolf pup survival: their relationship under varying ecological conditions

The relationship between pack size and two parameters of reproductive success (litter size at 7–8 months and pup weights at 5–6 months) were determined for two wolf ( Canis lupus ) populations in northern Minnesota. Pup weights were not correlated with pack size for either population. Litter size, however, was correlated with pack size, but the direction of the relationship varied between the two study populations. In the superior National Forest, where prey were scarce and the wolf population was declining from high densities, litter size and pack size were inversely related. Pairs produced more surviving pups than did larger packs with one or more potential helpers. In the Beltrami Island State Forest, where prey were relatively abundant and the wolf population was increasing, pack size and litter size were positively correlated. The results suggest that ecological factors, such as prey availability, affected the ability or willingness of various pack members to provide food or other care for the pups. The lack of correlation between number of auxiliaries and number of pups in canid populations with low and declining prey densities may be explained on the basis of heterogeneous prey density resulting in drastic annual variation in litter production. No study to date has measured the actual benefit that pups derive from helping by auxiliaries, and the costs and benefits of it. The relationships discussed herein can be considered valid only after such research is completed.

Behavioral Ecology and Sociobiology↗
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↗