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At least 703 records · Page 39Linked to original sources
USGS2010

Effects of earlier sea ice breakup on survival and population size of polar bears in western Hudson Bay

Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult to quantify. We used a flexible extension of Cormack-Jolly-Seber capture-recapture models to estimate population size and survival for polar bears (Ursus maritimus), one of the most ice-dependent of Arctic marine mammals. We analyzed data for polar bears captured from 1984 to 2004 along the western coast of Hudson Bay and in the community of Churchill, Manitoba, Canada. The Western Hudson Bay polar bear population declined from 1,194 (95% CI = 1,020-1,368) in 1987 to 935 (95% CI = 794-1,076) in 2004. Total apparent survival of prime-adult polar bears (5-19 yr) was stable for females (0.93; 95% CI = 0.91-0.94) and males (0.90; 95% CI = 0.88-0.91). Survival of juvenile, subadult, and senescent-adult polar bears was correlated with spring sea ice breakup date, which was variable among years and occurred approximately 3 weeks earlier in 2004 than in 1984. We propose that this correlation provides evidence for a causal association between earlier sea ice breakup (due to climatic warming) and decreased polar bear survival. It may also explain why Churchill, like other communities along the western coast of Hudson Bay, has experienced an increase in human-polar bear interactions in recent years. Earlier sea ice breakup may have resulted in a larger number of nutritionally stressed polar bears, which are encroaching on human habitations in search of supplemental food. Because western Hudson Bay is near the southern limit of the species' range, our findings may foreshadow the demographic responses and management challenges that more northerly polar bear populations will experience if climatic warming in the Arctic continues as projected.

Journal of Wildlife Management↗
USGS2026

Small creatures, big challenge: A review of current knowledge and assessment of research needs to inform water withdrawal management for the Duck River's freshwater mussel fauna

The Duck River is a remarkable national resource, boasting outstanding biodiversity (Ahlstedt et al. 2017). It contains 151 fish species, over 60 mussel species, and 22 snail species, many of which are federally listed (Etnier and Starnes 1993; Johnson et al. 2013; Ahlstedt et al. 2017; Womble and Rosenberger 2025a). The Duck River watershed is at a pivotal time in its management and ecological history due to significant growth in human population and economic activity. The consequent increase in surface water demand presents challenges for sustainable water resource management. The Tennessee Department of Environment and Conservation (TDEC) has permitted or proposed to permit eight water utilities to withdraw over 77 million gallons per day (mgd) from the Duck River, representing > 40% increase from previously permitted amounts (USFWS 2025). On November 20, 2024, Tennessee Governor Bill Lee signed Executive Order No 108 to ensure long-term stability of the Duck River watershed through balancing economic growth, water resource management, and environmental conservation. Some primary components of this plan are the creation of a Comprehensive Regional Drought Management Plan, the development of a Habitat Conservation Plan, and the establishment of the Duck River Watershed Planning Partnership (DRWPP). Although the planning partnership is not focused on a sole aspect of the Duck River, but the watershed as a whole, the mussel assemblages of the Duck River have been a particular focus due to their importance in providing ecosystem services, sensitivity to water quality, conservation status, and sensitivity to periodic drought conditions in this system. With multiple state and federal agencies involved in managing the Duck River’s unique water resources, a focused review on how future water management could affect the freshwater mussel communities in the Duck River will contribute to this process. Our objectives of this review are to: 1. Review the effects of changing flow regimes on mussels, with emphasis on the effect of droughts/low flows, highlighting key processes/factors affecting mussels. 2. Highlight critical data gaps that could allow future, evidence-based water management decisions in this system. 3. Propose research topics to address critical data gaps and enable evidence-based water management decisions that consider the needs of freshwater mussels. Freshwater mussels are a critical component of riverine ecosystems, providing ecosystem services including water filtration, nutrient cycling, and habitat provision (Vaughn et al. 2004; Haag 2012) that benefit human communities. Environmental flows, also referred to as ecological or e-flows, refer to the quantity, timing, and quality of water flows necessary to maintain the ecological health of rivers, wetlands, and other aquatic ecosystems (Acreman and Dunbar 2004; Acreman 2016). For freshwater mussels, environmental flows include maintaining a flow regime and associated water quality regimes that are favorable for both juveniles and adults while also seasonally supporting host fish and the survival of settling glochidia (i.e., larval mussels) in suitable environments (Gates et al. 2015). Freshwater mussels are adapted to the natural flow regime of their native streams, including seasonal variability in flows. As sedentary filter feeders, mussels require adequate water flow to provide oxygen and food (Allen and Vaughn 2009); however, they also require periods of low flow to increase access to fish hosts and to ensure juveniles are not displaced (Gates et al 2015). Mussels are sensitive to water quality conditions, including pollutants, sedimentation, and artificial alterations of temperature and pH (Strayer and Malcom 2012). Mussel community characteristics, including presence, abundance, and species richness, generally increase with stream size (e.g., stream order); however, responses to changes in flow conditions are often species-specific, and the magnitude and timing of extreme flow conditions have more predictive power for mussel community response than general changes in flow (Lopez and Vaughn 2021). Complex hydraulic variables, such as relative shear stress and Reynolds number, can be strong predictors of mussel community responses because they combine simple hydraulic variables (e.g., velocity, depth) with stream channel characteristics, such as substrate composition and dynamics. Droughts directly and indirectly affect mussels by influencing their physiology, behavior, reproduction, and ecosystem roles. Mass mussel die-offs during droughts and low water conditions are widely documented (Vaughn et al. 2015; Sousa et al. 2018; Dubose et al. 2019). Droughts can also lead to a shift in mussel community composition, with drought-tolerant species becoming more dominant while more sensitive species experience declines (Galbraith et al, 2010; Lopez et al. 2022; Vaughn and Atkinson 2025). Droughts affect mussels through direct mortality from stranding as well as physiological stress from altered water temperature and quality, reduced habitat and food availability and quality, increased predation and competition, disruption of reproductive cycles, and increased susceptibility to disease and pathogens. Although the effects of droughts, water withdrawals, and low flow conditions on mussels are an increasing area of study, there is a general paucity of data-driven consensus regarding optimal mitigation approaches and strategies (Cushway et al. 2024). Long-term management decisions regarding water withdrawals, particularly during extended or multi-year drought conditions, may consider factors beyond direct mortality such as the sublethal effects of drought and low flow conditions on freshwater mussels for a comprehensive understanding of the effects of prolonged low flows on freshwater mussels and aquatic communities.

Tennessee↗
USGS2003

Importance of the predator's ecological neighborhood in modeling predation on migrating prey

Most mathematical descriptions of predator-prey interactions fail to take into account the spatio-temporal structures of the populations, which can lead to errors or misinterpretations. For example, a compact pulse of prey migrating through a field of quasi-stationary predators may not be well described by standard predator-prey models, because the predators and prey are unlikely to be well mixed; that is, the prey may be exposed to only a fraction of the predator population at a time. This underscores the importance of properly accounting for the ecological neighborhood, or effective feeding range, of predators in models. We illustrate this situation with a series of models of salmon smolts migrating through a reservoir arrayed with predators. The reservoir is divided into a number of longitudinal compartments or spatial cells, the length of each cell representing the upstream-downstream range over which predators can forage. In this series of models a 100-km-long reservoir is divided, successively into 2, 5, 10, 25, 50, 100, 200, and 400 cells, with respective cell lengths of 50, 20, 10, 4, 2, 1, 0.5, and 0.25 km. We used a detailed individual-based simulation model at first, but to ensure robustness of results we supplemented this with a simple analytic model. Both models showed sharp differences in the predicted mortality to a compact pulse of smolt prey moving through the reservoir, depending on the number of spatial cells in the model. In particular, models with fewer than about 10 cells vastly overpredicted the amount of mortality due to predators with activity ranges of not more than a few kilometers. These results corroborate recent theoretical and simulation studies on the importance of spatial scale and behavior in modeling predator-prey dynamics.

Oikos↗
USGS2016

Spatially explicit modeling in ecology: A review

The use of spatially explicit models (SEMs) in ecology has grown enormously in the past two decades. One major advancement has been that fine-scale details of landscapes, and of spatially dependent biological processes, such as dispersal and invasion, can now be simulated with great precision, due to improvements in computer technology. Many areas of modeling have shifted toward a focus on capturing these fine-scale details, to improve mechanistic understanding of ecosystems. However, spatially implicit models (SIMs) have played a dominant role in ecology, and arguments have been made that SIMs, which account for the effects of space without specifying spatial positions, have an advantage of being simpler and more broadly applicable, perhaps contributing more to understanding. We address this debate by comparing SEMs and SIMs in examples from the past few decades of modeling research. We argue that, although SIMs have been the dominant approach in the incorporation of space in theoretical ecology, SEMs have unique advantages for addressing pragmatic questions concerning species populations or communities in specific places, because local conditions, such as spatial heterogeneities, organism behaviors, and other contingencies, produce dynamics and patterns that usually cannot be incorporated into simpler SIMs. SEMs are also able to describe mechanisms at the local scale that can create amplifying positive feedbacks at that scale, creating emergent patterns at larger scales, and therefore are important to basic ecological theory. We review the use of SEMs at the level of populations, interacting populations, food webs, and ecosystems and argue that SEMs are not only essential in pragmatic issues, but must play a role in the understanding of causal relationships on landscapes.

Ecosystems↗
USGS2025

Environmental DNA monitoring of invasive Central American boas in St. Croix at Salt River Bay National Historical Park and Ecological Preserve (SARI)

Invasive Central American boas ( Boa imperator ) have established a reproducing population on the western side of St. Croix, U.S. Virgin Islands but prevalence throughout the island is largely unknown. The large snakes threaten endemic and endangered species through competition and predation, jeopardizing island biodiversity. Environmental DNA (eDNA) methods were used to investigate occurrence and focal areas for management efforts in the Salt River Bay National Historical Park and Ecological Preserve (SARI). To validate a previously developed assay, we collected tissue samples and 13 × 60 mL water samples from a captive boa enclosure in St. Croix. We implemented this assay for both a pilot and main field sampling effort. The pilot in December 2023 resulted in analysis of 7 × 60 mL water samples per site from SARI (3 sites) and from the western forests where boas are established (1 site). The main sampling event in July 2024 collected 15 × 60 mL water samples per site within SARI (11 sites) and western forests (4 sites). Pilot sample replicates were filtered individually, while main samples were consolidated into groups, resulting in seven replicates for pilot sites and five replicates for main event sites, totaling 103 environmental samples. eDNA was isolated using a modified phenol-chloroform isolation method to remove PCR inhibitors, and target eDNA was amplified using droplet digital PCR technology. Water samples from the captive boa amplified target eDNA in 12 of 13 samples, indicating assay effectiveness ex-situ. Low concentrations of eDNA (below the 95% limit of detection) were amplified in 4 of 5 sites in the western forest and in 8 of 14 sites within the National Historic Park. Overall, boa eDNA concentrations were consistently low, as expected in water samples targeting a semi-arboreal snake species with a low rate of eDNA shedding. Further optimization of methods could enable recovery of greater eDNA concentrations in future studies. Additional eDNA method testing and ground-truthing may help to improve the assessment of invasive Boa imperator in St. Croix.

Science Report↗
USGS2008

Checklists: An under-used tool for the inventory and monitoring of plants and animals

Checklists are widely used to catalog field observations of plants and animals. We used 25 years of bird checklist data from the Études des Populations d’Oiseaux du Quebec program to examine the ability of checklists to produce reliable conservation, management, and ecological information. We found that checklists can provide reliable information on changes in bird populations, phenology, and geographic and climate abundance patterns at local, regional, and continental scales. Professional and amateur conservation groups that need to develop extensive monitoring programs should take advantage of the fact that checklists, unlike other time-consuming and expensive techniques, can be used to detect large-scale changes in an entire community of species.

Quebec↗
USGS2014

Reply to Efford on ‘Integrating resource selection information with spatial capture-recapture’

1. We proposed ( Methods in Ecology and Evolution , 2013, 4) a model for combining telemetry data with spatial capture–recapture (SCR) data that was vigorously criticized by Efford ( Methods in Ecology and Evolution , 2014, 000, 000). Efford's main claim was that our encounter probability model was incorrect, and therefore our R code and simulation results were wrong. 2. In fact, our encounter probability model is correct under the Poisson point process model that we used as a basis for our integrated model. On the other hand, the basis for Efford's claims clearly rest on the assumption of an alternative model which, while possibly useful, is distinct from that analysed in Royle et al. (Methods in Ecology and Evolution, 2013, 4). 3. A key point of Royle et al. ( Methods in Ecology and Evolution , 2013, 4) was that active resource selection induces heterogeneity in encounter probability which, if unaccounted for, should bias estimates of population size or density. The models of Royle et al. ( Methods in Ecology and Evolution , 2013, 4) and Efford ( Methods in Ecology and Evolution , 2014, 000, 000) merely amount to alternative models of resource selection, and hence varying amounts of heterogeneity in encounter probability.

Methods in Ecology and Evolution↗
USGS2006

Spatial and Temporal Migration Patterns of Neotropical Migrants in the Southwest Revealed by Stable Isotopes

Executive Summary We used stable hydrogen isotopes (?D) to investigate both temporal and spatial patterns during spring migration for three warbler species, Wilson's Warbler (Wilsonia pusilla), MacGillivray's Warbler (Oporornis tolmiei), and Nashville Warbler (Vermivora ruficapilla), across multiple migration routes in southwest North America. A strong correlation between stable hydrogen isotope values of feathers and the local precipitation at sites where feathers where collected across the breeding range for all three species reaffirmed that stable hydrogen isotopes were a good predictor of breeding locations. For the Wilson's Warbler, we found a significant negative relationship between the date when warblers passed through the sampling station and ?D values of their feathers, indicating that warblers who bred the previous season at southern latitudes migrated through the migration stations earlier than did warblers that had previously bred at more northern latitudes. This pattern was consistent across their southwestern migration route (5 sites sampled) and was consistent between years. Comparing ?D values between migration stations also showed a shift towards more negative ?D values from the western to the eastern migration stations sampled in this study, which corresponded to different geographical regions of the Wilson's Warblers' western breeding range. For MacGillivray's Warbler we found the same temporal pattern as Wilson's Warbler, with warblers that bred the previous season at southern latitudes migrating through the migration stations earlier than warblers that had previously bred at more northern latitudes. This pattern was consistent at the Lower Colorado River and Arivaca Creek, the two sites where sample sizes were adequate to test these hypotheses. Comparison of the ?D between the two sites indicated that the majority of warblers migrating through these stations were breeding within a geographically limited area of MacGillivray's Warblers' overall breeding range. This is in contrast to the larger range of ?D values for Wilson's Warblers at these two sites, which corresponded to a broader area across their breeding range. Feathers were also collected across MacGillivray's Warblers' wintering range, and stable hydrogen isotope analysis indicated a significant positive relationship with wintering latitude. Because the ?D value of MacGillivray's Warblers' feathers reflects the ?D value of their breeding locations, with more negative values representing more northerly breeding latitudes, this positive relationship between feather ?D and wintering latitude indicated that warblers wintering at more southern latitudes bred at more northern latitudes. This supports a leapfrog migration system for MacGillivray's Warblers and is the first documentation of such a pattern. We did not find a temporal pattern to the spring migration of Nashville Warblers. This lack of temporal pattern could be due to the reduced size of the breeding and wintering ranges of Nashville Warblers, both of which could decrease the advantages of a temporal migration pattern. A small population of Nashville Warblers also breeds on the California coast and the sporadic nature of migration for Nashville Warblers in the southwest suggests that in some years more Nashville Warblers may winter along the California coast. The information in this study has increased our understanding of both spatial and temporal patterns of migration for three neotropical migrant birds and has important implications for understanding the ecology and evolution of migrants and factors influencing overall population dynamics.

Open-File Report↗
USGS2021

When a typical jumper skips: Itineraries and staging habitats used by Red Knots (Calidris canutus piersmai) migrating between northwest Australia and the New Siberian Islands

The ecological reasons for variation in avian migration, with some populations migrating across thousands of kilometres between breeding and non-breeding areas with one or few refuelling stops, in contrast to others that stop more often, remain to be pinned down. Red Knots Calidris canutus are a textbook example of a shorebird species that makes long migrations with only a few stops. Recognizing that such behaviours are not necessarily species-specific but determined by ecological context, we here provide a description of the migrations of a relatively recently described subspecies ( piersmai ). Based on data from tagging of Red Knots on the terminal non-breeding grounds in northwest Australia with 4.5- and 2.5-g solar-powered Platform Terminal Transmitters (PTTs) and 1.0-g geolocators, we obtained information on 19 route-records of 17 individuals, resulting in seven complete return migrations. We confirm published evidence that Red Knots of the piersmai subspecies migrate from NW Australia and breed on the New Siberian Islands in the Russian Arctic and that they stage along the coasts of southeastern Asia, especially in the northern Yellow Sea in China. Red Knots arrived on the tundra breeding grounds from 8 June onwards. Southward departures mainly occurred in the last week of July and the first week of August. We documented six non-stop flights of over c . 5000 km (with a maximum of 6500 km, lasting 6.6 days). Nevertheless, rather than staging at a single location for multiple weeks halfway during migration, piersmai -knots made several stops of up to a week. This was especially evident during northward migration, when birds often stopped along the way in southeast Asia and ‘hugged’ the coast of China, thus flying an additional 1000–1500 km compared with the shortest possible (great circle route) flights between NW Australia and the Yellow Sea. The birds staged longest in areas in northern China, along the shores of Bohai Bay and upper Liaodong Bay, where the bivalve Potamocorbula laevis , known as a particularly suitable food for Red Knots, was present. The use of multiple food-rich stopping sites during northward migration by piersmai is atypical among subspecies of Red Knots. Although piersmai apparently has the benefit of multiple suitable stopping areas along the flyway, it is a subspecies in decline and their mortality away from the NW Australian non-breeding grounds has been elevated.

New Siberian Islands↗
USGS1999

Of elephants and blind men: Deer management in the U.S. National Parks

Overabundant populations of white-tailed deer ( Odocoileus virginianus ) are becoming common in the eastern United States. Faced with burgeoning deer populations in eastern parks, the National Park Service (NPS) formulated policy based on its long experience with ungulate management in western parks. That the NPS failed to find a management solution acceptable to its many constituencies was inevitable. Like blind men touching different parts of an elephant and disagreeing about its form, those engaged in the debate about deer management in parks are viewing different parts of the ecological system. None has seen the entire system, and consequently, there is neither common agreement on the nature of the problem nor on the solutions. We explore the quandary of deer management in eastern parks by addressing three questions: (1) Can the National Park Service reconcile its management goals with those of its neighbors? (2) Can thresholds be identified for determining when to intervene in natural processes? (3) Is there a scientific foundation for proceeding with effective management of deer? We argue that reconciling the NPS management with that of state conservation agencies is not possible because management policy guides these agencies in opposite directions: the NPS is charged with limiting human impact on ecological processes, and state agencies are charged with exerting human control over population abundance. Questions about thresholds and a scientific basis for management arise from concern that irrupting deer populations are a manifestation of disrupted natural processes. Several population growth paradigms are at the heart of this ecological question. The science provides no consensus about which of these paradigms are appropriate to deer in eastern ecosystems. Thus, it is premature to expect science to identify if or when natural processes have been disrupted. While the NPS cannot effectively achieve its goals without better science, neither can it wait for science to fully understand the dynamics of plant–herbivore interactions. The best hope for resolving both the biological and political dilemmas surrounding deer management is through an adaptive management approach.

Ecological Applications↗
USGS2005

Should we expect population thresholds for wildlife disease?

Host population thresholds for invasion or persistence of infectious disease are core concepts of disease ecology, and underlie on-going and controversial disease control policies based on culling and vaccination. Empirical evidence for these thresholds in wildlife populations has been sparse, however, though recent studies have narrowed this gap. Here we review the theoretical bases for population thresholds for disease, revealing why they are difficult to measure and sometimes are not even expected, and identifying important facets of wildlife ecology left out of current theories. We discuss strengths and weaknesses of selected empirical studies that have reported disease thresholds for wildlife, identify recurring obstacles, and discuss implications of our imperfect understanding of wildlife thresholds for disease control policy.

Trends in Ecology and Evolution↗
USGS2022

Mechanisms of forest resilience

Ecosystems are dynamic systems with complex responses to environmental variation. In response to pervasive stressors of changing climate and disturbance regimes, many ecosystems are realigning rapidly across spatial scales, in many cases moving outside of their observed historical range of variation into alternative ecological states. In some cases, these new states are transitory and represent successional stages that may ultimately revert to the pre-disturbance condition; in other cases, alternative states are persistent and potentially self-reinforcing, especially under conditions of altered climate, disturbance regimes, and influences of non-native species. These reorganized states may appear novel, but reorganization is a characteristic ecosystem response to environmental variation that has been expressed and documented throughout the paleoecological record. Resilience, the ability of an ecosystem to recover or adapt following disturbance, is an emergent property that results from the expression of multiple mechanisms operating across levels of organism, population, and community. We outline a unifying framework of ecological resilience based on ecological mechanisms that lead to outcomes of persistence, recovery, and reorganization. Persistence is the ability of individuals to tolerate exposure to environmental stress, disturbance, or competitive interactions. As a direct expression of life history evolution and adaptation to environmental variation and stress, persistence is manifested most directly in survivorship and continued growth and reproduction of established individuals. When persistence has been overcome (e.g., following mortality from stress, disturbance, or both), populations must recover by reproduction. Recovery requires the establishment of new individuals from seed or other propagules following dispersal from the parent plant. When recovery fails to re-establish the pre-disturbance community, the ecosystem will assemble into a new state. Reorganization occurs along a gradient of magnitude, from changes in the relative dominance of species present in a community, to individual species replacements within an essentially intact community, to complete species turnover and shift to dominance by plants of different functional types, e.g. transition from forest to shrub or grass dominance. When this latter outcome is persistent and involves reinforcing mechanisms, the resulting state represents a vegetation type conversion (VTC), which in this framework represents an end member of reorganization processes. We explore reorganization in greater detail as this phase is increasingly observed but the least understood of the resilience responses. This resilience framework provides a direct and actionable basis for ecosystem management in a rapidly changing world, by targeting specific components of ecological response and managing for sustainable change.

Forest Ecology and Management↗
USGS2013

Animal migration and risk of spread of viral infections

The potential contribution of migration towards the spread of disease is as varied as the ecology of the pathogens themselves and their host populations. This chapter outlines multiple examples of viral diseases in animal populations and their mechanisms of viral spread. Many species of insects, mammals, fish, and birds exhibit migratory behavior and have the potential to disperse diseases over long distances. The majority of studies available on viral zoonoses have focused on birds and bats, due to their highly migratory life histories. A number of studies have reported evidence of changes in the timing of animal migrations in response to climate change. The majority indicate an advancement of spring migration, with few or inconclusive results for fall migration. Predicting the combined effects of climate change on migratory patterns of host species and epidemiology of viral pathogens is complex and not fully realistic.

Book chapter↗
USGS2025

Sinoatrial contracaeciasis in Johnny Darters ( Etheostoma nigrum ) and Plains Topminnow ( Fundulus sciadicus ) from the South Platte drainage, Colorado

Intra-sinoatrial nematodes were incidentally recognized in wild-caught Colorado Johnny Darters ( Etheostoma nigrum , JD) in 2020–2021 and in Colorado Plains Topminnow ( Fundulus sciadicus , PTM) in 2023-2024. PTM and JD were evaluated histologically. Nematodes dissected from PTM were used for morphologic evaluation and molecular identification. The first and second internal transcribed spacers (ITS1 and ITS2) of ribosomal DNA were sequenced. Sinoatrial nematodes were found in two of 1232 JD (0.2%) and nine of 110 PTM (8.2%). Worms caused dilation or aneurysm of the sinus venosus. One JD had severe sinus venosus phlebitis. Morphologic, histologic and molecular features were diagnostic for Contracaecum spp. This is the first identification of larval Contracaecum in PTM, the first record of an intravascular nematode in this species, and the first documentation of vascular localization of Contracaecum larvae in JD. Vascular pathology could result in increased susceptibility to predation and favour the completion of the nematode life cycle. Parasites could become detrimental to population survival, especially those that are stressed by ecological and anthropogenic factors.

Colorado↗
USGS2016

Design for mosquito abundance, diversity, and phenology sampling within the National Ecological Observatory Network

The National Ecological Observatory Network (NEON) intends to monitor mosquito populations across its broad geographical range of sites because of their prevalence in food webs, sensitivity to abiotic factors and relevance for human health. We describe the design of mosquito population sampling in the context of NEON’s long term continental scale monitoring program, emphasizing the sampling design schedule, priorities and collection methods. Freely available NEON data and associated field and laboratory samples, will increase our understanding of how mosquito abundance, demography, diversity and phenology are responding to land use and climate change.

Ecosphere↗
USGS2021

Seasonal variation in resource selection by subadult golden eagles in the Great Basin Desert

Golden eagles Aquila chrysaetos are a long-lived and wide-ranging species believed to be stable or in slight decline across North America. Golden eagles have an extended subadult stage (4–5 years) that is critical to maintaining recruitment into the breeding population and population viability. Compared to adult golden eagles, the ecology of subadult golden eagles (hereafter, subadults) has received little attention. We investigated patterns of resource selection for subadults in the Great Basin Desert of the western United States during summer and winter, 2013–2019. We monitored 46 subadults with GPS transmitters and related locations (n = 99 037) with predictors hypothesized to influence seasonal patterns of space use with mixed-effects logistic regression. Subadults selected for ridges and upper slopes in summer and winter, but higher elevations in summer. Subadults showed weak selection for lower ridge density in summer, which was likely facilitated by selection for areas with greater thermal wind current potential. In contrast, subadults showed strong selection for higher ridge density in winter. Subadults selected areas further from roads in summer and closer to roads and electrical transmission lines in winter, which may be related to winter scavenging of road-killed ungulates. Resource selection functions suggested subadults selected for shrublands and woodlands in both seasons, but odds ratios revealed that during winter subadults avoided shrublands and increased selection of woodlands relative to summer. Subadults selected for areas with infrequent fires in both seasons; areas with frequent fires were avoided in summer but selected for in winter. Seasonal changes in resource selection suggested that subadults used woodlands more than expected, potentially reflecting spatial partitioning by subadults to lower-quality habitats to minimize competition with breeding adults during winter when energetic demands for thermoregulation were presumably higher and prey more limited.

Utah↗
USGS2021

Evaluating low flow patterns, drivers and trends in the Delaware River Basin

In the humid, temperate Delaware River Basin (DRB) where water availability is generally reliable, summer low flows can cause competition between various human and ecological water uses. As temperatures continue to rise, population increases and development expands, it is critical to understand historical low flow variability to anticipate and plan for future flows. Using a sample of 325 U.S. Geological Survey gages, we evaluated spatial patterns in several low flow metrics, the biophysical and climatic drivers of these metrics, and trends in low flows for two periods: 1950-2018 and 1980-2018. We calculated the annual 7-day low flow and date, low flow deficit as the departure below a long-term daily flow threshold and the number of discrete low flow periods below this threshold. We also aggregated several climate metrics to watershed scale and used existing watershed properties quantifying land cover, topography, soils, geology, and human activity. Random forest models were used to assess the hierarchy of variable importance in explaining mean-annual low flow variability for each low flow metric using all gages. We find muted regional patterns in mean-annual low flow and low flow variability, likely due to the myriad of anthropogenic, landscape, and flow modifications that obscure flow regimes from their natural characteristics. In contrast, individual years show markedly different spatial patterns in low flow magnitude and severity. Coincident with increases in precipitation, 7-day low flows have generally increased and low flow deficits decreased for both 1950-2018 and 1980-2018 periods. However, 7-day low flows have decreased in the Coastal Plain physiographic province where water use and impervious area have increased in recent decades, highlighting the effects of land and water management on low flows. With continued change expected in the DRB, additional research needs are highlighted to enable estimation of future low flows and to plan for periods of prolonged low flow.

Delaware, New Jersey, New York, Pennsylvania↗
USGS2020

A synthesis of the biology and ecology of sculpin species in the Laurentian Great Lakes and implications for the adaptive capacity of the benthic ecosystem

The Laurentian Great Lakes have experienced recent ecosystem changes that could lead to reductions in adaptive capacity and ultimately a loss of biodiversity and production throughout the food web. Observed changes in Great Lakes benthic communities include declines of native species and widespread success of invasive species like dreissenid mussels in all but Lake Superior. Understanding the ecology of native benthic deepwater preyfish and the reasons for their declines is important for predicting future losses in adaptive capacity and diversity, as well as managing the Great Lakes ecosystem to avoid such losses. Native sculpin species ( Cottus bairdii , C. cognatus , C. ricei , Myoxocephalus thompsonii ) historically were among the most abundant of the Great Lakes native deepwater benthic preyfish community and are an important link between offshore benthic and pelagic food webs. With one exception, these species have declined in abundance throughout the Great Lakes in recent years, but relatively little is known about their biology and ecology. This review synthesizes the available knowledge for the Great Lakes sculpin species and provides suggestions for future research efforts, which include understanding reproductive ecology and spawning behavior, connectivity and dispersal of populations, early life history, and influences of interactions with native and non-native species.

Great Lakes↗