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USGS2017

Post-breeding migration and connectivity of red knots in the Western Atlantic

Red knots ( Calidris canutus rufa ) have 3 distinct nonbreeding regions: 1 in the southeastern United States and Caribbean, another on the northeast coast of Brazil in the Maranhão region, and a third along the Patagonian coasts of Chile and Argentina. Effective conservation and recovery of this threatened long-distance migrant will require knowledge of population structure, migration ecology, and abundance and distribution throughout the annual cycle. We conducted a stopover population and biogeographic assessment of knots at the Altamaha River Delta, Georgia, an important stopover area in the southeastern United States. We estimated stopover population size and stopover duration during post-breeding migration in 2011 at the Altamaha study area using mark-resight data, and we inferred nonbreeding regions for this stopover population using stable isotope ratios of carbon and nitrogen in feathers, and observations (sightings and captures) during boreal winter from across the hemisphere. With an integrated Bayesian analysis of all these data, we also estimated the number of birds in the southeastern United States and northern Brazil during boreal winter. For mark-resight analyses in Georgia, we made observations of marked individuals during 14 weeks from early August to early November 2011 and detected 814 individually marked birds. We used the Jolly-Seber mark-recapture model and estimated the southbound passage population at approximately 23,400 red knots. In ongoing studies elsewhere, isotope samples were collected from 175 (21%) of the 814 birds detected in our study, and ≥1 sighting or capture record during boreal winter was located in data repositories for 659 birds (81%). Isotopic signatures and boreal winter records indicate that the majority (82–96%) of the birds that stopped at the Altamaha Delta spend the boreal winter in the northern part of the nonbreeding range (southeast USA, Caribbean, and northern Brazil). Knots migrating to the southeastern United States, Caribbean, or Brazil remained on the Altamaha Delta for 42 days, whereas birds migrating to Tierra del Fuego remained only 21 days. Combining our estimate of the Altamaha stopover population size (23,400 birds) and the estimated proportion in the northern nonbreeding region (82–96%), we derived a minimum estimate of the number of knots in the southeastern United States, Caribbean, and northern South America during the boreal winter: approximately 20,800 knots, of which approximately 10,400 knots occupy the southeastern United States and 5,400 occupy Brazil. Our results provide additional evidence that coastal Georgia is an important migration area for red knots, and provide information about population structure and migratory connectivity that will be valuable for conservation planning.

Georgia↗

USGS2003

Effect of different sampling schemes on the spatial placement of conservation reserves in Utah, USA

We evaluated the effect of three different sampling schemes used to organize spatially explicit biological information had on the spatial placement of conservation reserves in Utah, USA. The three sampling schemes consisted of a hexagon representation developed by the EPA/EMAP program (statistical basis), watershed boundaries (ecological), and the current county boundaries of Utah (socio-political). Four decision criteria were used to estimate effects, including amount of area, length of edge, lowest number of contiguous reserves, and greatest number of terrestrial vertebrate species covered. A fifth evaluation criterion was the effect each sampling scheme had on the ability of the modeled conservation reserves to cover the six major ecoregions found in Utah. Of the three sampling schemes, county boundaries covered the greatest number of species, but also created the longest length of edge and greatest number of reserves. Watersheds maximized species coverage using the least amount of area. Hexagons and watersheds provide the least amount of edge and fewest number of reserves. Although there were differences in area, edge and number of reserves among the sampling schemes, all three schemes covered all the major ecoregions in Utah and their inclusive biodiversity. ?? 2003 Elsevier Science Ltd. All rights reserved.

Biological Conservation↗

USGS2019

An overview of the world’s plovers

Plovers of the genus Charadrius and their close allies are a diverse group, numbering 40 species, many with subspecies. They breed on all continents except Antarctica, in open, sparsely vegetated habitats of tundra and grasslands, and along shores of oceans, rivers, and inland lakes. Most are migratory, especially those breeding in arctic and temperate regions; others are partial migrants or sedentary. On migration, they are poorly studied and do not always correspond to the typical shorebird (i.e., sandpiper) pattern characterized by dense flocks concentrating at a few staging areas. Their foraging ecologies are rather uniform in that all species search visually for prey using a “run-stop-peck” maneuver. Breeding birds defend nesting and foraging territories while nonbreeding birds forage in loose flocks, which may stem from individuals minimizing interference with conspecifics while enhancing benefits of shared vigilance for predators. In breeding, they are conservative, laying two to four eggs at daily or longer intervals; replacement clutches are common, especially in species with prolonged breeding seasons. Precocial young hatch after comparatively long incubation that is correlated with development of neural centers associated with vision. Their mating systems are a mix of social monogamy and biparental care, with frequent sequential polygamy, especially in temperate and tropical taxa that breed for extended periods. Population sizes vary over several orders of magnitude; several species are highly endangered. Other species are abundant and widely distributed, although their populations may also be in decline. Regardless of their status, most plovers occupy habitats throughout the year that put them at conservation risk owing to anthropogenic factors including climate change, human disturbance, habitat loss, and predation. In this book, we draw from the expertise of an international group of researchers to outline the ecologies, behaviors, and challenges of plovers throughout the annual cycle so that decision makers can be most successful in their endeavors to conserve and manage populations.

Book chapter↗

USGS2019

Trends in biodiversity and habitat quantification tools used for market‐based conservation in the United States

Market-based conservation mechanisms are designed to facilitate conservation and mitigation actions for habitat and biodiversity. Their potential is partly hindered, however, by issues surrounding the quantification tools used to assess habitat quality and functionality. Specifically, a lack of transparency and standardization in tool development and gaps in tool availability are cited concerns. To address these issues, we collected information about tools used in United States conservation mechanisms such as eco-label and payments for ecosystem services (PES) programs, conservation banking, and habitat exchanges. We summarized information about tools and explored trends among and within mechanisms using criteria detailing geographic, ecological, and technical features of tools. We identified 69 tools that assessed at least 34 species and 39 habitat types. Where tools reported pricing, 98% were freely available. Most tools required a moderate or greater level of user skill. More tools were applied to states along the west coast of the United States than elsewhere and the level of tool transferability varied markedly among mechanisms. Tools most often incorporated conditions at numerous spatial scales, frequently addressed multiple risks to site viability, and required from 1 to 83 data inputs. Finally, average tool complexity estimates were similar among all mechanisms except PES programs. Our results illustrate the diversity among tools in their ecological features, data needs, and geographic application, supporting concerns about a lack of standardization. However, consistency among tools in user skill requirements, the incorporation of multiple spatial scales, and complexity highlight important commonalities that could serve as a starting point for establishing more standardized tool development and feature incorporation processes. Greater standardization in tool design may not only expand market participation, but may also facilitate a needed assessment of the effectiveness of market-based conservation.

Conservation Biology↗

USGS1998

Molecular contributions to conservation

Recent advances in molecular technology have opened a new chapter in species conservation efforts, as well as population biology. DNA sequencing, MHC (major histocompatibility complex), minisatellite, microsatellite, and RAPD (random amplified polymorphic DNA) procedures allow for identification of parentage, more distant relatives, founders to new populations, unidentified individuals, population structure, effective population size, population-specific markers, etc. PCR (polymerase chain reaction) amplification of mitochondrial DNA, nuclear DNA, ribosomal DNA, chloroplast DNA, and other systems provide for more sophisticated analyses of metapopulation structure, hybridization events, and delineation of species, subspecies, and races, all of which aid in setting species recovery priorities. Each technique can be powerful in its own right but is most credible when used in conjunction with other molecular techniques and, most importantly, with ecological and demographic data collected from the field. Surprisingly few taxa of concern have been assayed with any molecular technique. Thus, rather than showcasing exhaustive details from a few well-known examples, this paper attempts to present a broad range of cases in which molecular techniques have been used to provide insight into conservation efforts.

Ecology↗

USGS2019

Estimating offsets for avian displacement effects of anthropogenic impacts

Biodiversity offsetting, or compensatory mitigation, is increasingly being used in temperate grassland ecosystems to compensate for unavoidable environmental damage from anthropogenic developments such as transportation infrastructure, urbanization, and energy development. Pursuit of energy independence in the United States will expand domestic energy production. Concurrent with this increased growth is increased disruption to wildlife habitats, including avian displacement from suitable breeding habitat. Recent studies at energy-extraction and -generation facilities have provided evidence for behavioral avoidance and thus reduced use of habitat by breeding waterfowl and grassland birds in the vicinity of energy infrastructure. To quantify and compensate for this loss in value of avian breeding habitat, it is necessary to determine a biologically-based currency so that the sufficiency of offsets in terms of biological equivalent value can be obtained. We describe a method for quantifying the amount of habitat needed to provide equivalent biological value for avifauna displaced by energy and transportation infrastructure, based on the ability to define five metrics: impact distance, impact area, pre-impact density, percent displacement, and offset density. We calculate percent displacement values for breeding waterfowl and grassland birds and demonstrate the applicability of our avian-impact offset method using examples for wind and oil infrastructure. We also apply our method to an example in which the biological value of the offset habitat is similar to the impacted habitat, based on similarity in habitat type (e.g., native prairie), geographical location, land use, and landscape composition, as well as to an example in which the biological value of the offset habitat is dissimilar to the impacted habitat. We provide a worksheet that informs potential users how to apply our method to their specific developments and a framework for developing decision-support tools aimed at achieving landscape-level conservation goals.

Ecological Applications↗

USGS2017

Restricted gene flow between resident Oncorhynchus mykiss and an admixed population of anadromous steelhead

The species Oncorhynchus mykiss is characterized by a complex life history that presents a significant challenge for population monitoring and conservation management. Many factors contribute to genetic variation in O. mykiss populations, including sympatry among migratory phenotypes, habitat heterogeneity, hatchery introgression, and immigration (stray) rates. The relative influences of these and other factors are contingent on characteristics of the local environment. The Rock Creek subbasin in the middle Columbia River has no history of hatchery supplementation and no dams or artificial barriers. Limited intervention and minimal management have led to a dearth of information regarding the genetic distinctiveness of the extant O. mykiss population in Rock Creek and its tributaries. We used 192 SNP markers and collections sampled over a 5‐year period to evaluate the temporal and spatial genetic structures of O. mykiss between upper and lower watersheds of the Rock Creek subbasin. We investigated potential limits to gene flow within the lower watershed where the stream is fragmented by seasonally dry stretches of streambed, and between upper and lower watershed regions. We found minor genetic differentiation within the lower watershed occupied by anadromous steelhead ( F ST = 0.004), and evidence that immigrant influences were prevalent and ubiquitous. Populations in the upper watershed above partial natural barriers were highly distinct ( F ST = 0.093) and minimally impacted by apparent introgression. Genetic structure between watersheds paralleled differences in local demographics (e.g., variation in size), migratory restrictions, and habitat discontinuity. The evidence of restricted gene flow between putative remnant resident populations in the upper watershed and the admixed anadromous population in the lower watershed has implications for local steelhead productivity and regional conservation.

Washington↗

USGS2020

A hierarchical analysis of habitat area, connectivity, and quality on amphibian diversity across spatial scales

Habitat fragmentation can alter species distributions and lead to reduced diversity at multiple scales. Yet, the literature describing fragmentation effects on biodiversity patterns is contradictory and inconclusive, possibly because most studies fail to integrate spatial scale into experimental designs and statistical analyses. As a result, it is difficult to extrapolate the effects of fragmentation to large-scaled systems in which conservation management is of immediate importance. Objectives To explore the influence of fragmentation on biodiversity across scales, we (1) estimated the effects of habitat area, connectivity, and quality at both local (i.e. community) and regional (i.e. metacommunity) scales; and (2) evaluated the direction, magnitude, and precision of these effect estimates at both spatial scales. Methods We developed a multi-region community occupancy model to analyze 13 years (2005-2017) of amphibian monitoring data within the National Capital Region, a network of U.S. National Parks. Results Overall, we found a positive effect of park size and a negative effect of isolation on species richness at the park-level (i.e. metacommunity), and generally positive effects of wetland area, connectivity, and quality on species richness at the wetland-level (i.e. community), although parameter estimates varied among species. Covariate effects were less precise, but effects sizes were larger, at the local wetland-level as compared to the larger park-level scale. Conclusions Our analysis reveals how scale can mediate interpretation of results from scientific studies, which might help explain conflicting narratives concerning the impacts of fragmentation in the published literature. Our hierarchical framework can help managers and policymakers elucidate the relevant spatial scale(s) to target conservation efforts.

Landscape Ecology↗

USGS2002

Variation in survivorship of a migratory songbird throughout its annual cycle

1. Demographic data from both breeding and non-breeding periods are needed to manage populations of migratory birds, many of which are declining in abundance and are of conservation concern. Although habitat associations, and to a lesser extent, reproductive biology, are known for many migratory species, few studies have measured survival rates of these birds at different parts of their annual cycle. 2. Cormack–Jolly–Seber models and Akaike’s information criterion model selection were used to investigate seasonal variation in survival of a Nearctic – Neotropical migrant songbird, the black-throated blue warbler, Dendroica caerulescens . Seasonal and annual survival were estimated from resightings of colour-ringed individuals on breeding grounds in New Hampshire, USA from 1986 to 2000 and on winter quarters in Jamaica, West Indies from 1986 to 1999. Warblers were studied each year during the May–August breeding period in New Hampshire and during the October–March overwinter period in Jamaica. 3. In New Hampshire, males had higher annual survival (0·51 ± 0·03) and recapture probabilities (0·93 ± 0·03) than did females (survival: 0·40 ± 0·04; recapture: 0·87 ± 0·06). In Jamaica, annual survival (0·43 ± 0·03) and recapture (0·95 ± 0·04) probabilities did not differ between sexes. Annual survival and recapture probabilities of young birds (i.e. yearlings in New Hampshire and hatch-year birds in Jamaica) did not differ from adults, indicating that from the time hatch-year individuals acquire territories on winter quarters in mid-October, they survive as well as adults within the same habitat. 4. Monthly survival probabilities during the summer (May–August) and winter (October–March) stationary periods were high: 1·0 for males in New Hampshire, and 0·99 ± 0·01 for males in Jamaica and for females in both locations. 5. These annual and seasonal survival estimates were used to calculate warbler survival for the migratory periods. Monthly survival probability during migration ranged from 0·77 to 0·81 ± 0·02. Thus, apparent mortality rates were at least 15 times higher during migration compared to that in the stationary periods, and more than 85% of apparent annual mortality of D. caerulescens occurred during migration. 6. Additional data from multiple species, especially measures of habitat-specific demography and dispersal, will improve our understanding of the relative impacts of the breeding, migratory, and winter periods on population dynamics of migratory birds and thus enhance future conservation efforts.

Journal of Animal Ecology↗

USGS2007

Using conservation value to assess land restoration and management alternatives across a degraded oak savanna landscape

1. Managers considering restoration of landscapes often face a fundamental challenge - what should be the habitat composition of the restored landscape? We present a method for evaluating an important conservation trade-off inherent in making that decision. 2. Oak savannas and grasslands were historically widespread across central North America but are now rare. Today, in north-west Indiana, USA, habitats spanning a range of woody vegetation density, from nearly treeless open habitats to forests, occur across the conserved landscape where savannas probably once dominated. To understand the benefits of different potential landscape compositions, we evaluated how different proportions of five habitats - open, savanna, woodland, scrub and forest - might affect the conservation value of the north-west Indiana landscape for birds. Two variables of potential conservation importance were examined: species diversity, a measure of avian community richness, and conservation index, the percentage of a bird species' global population occurring on a hectare of landscape, summed across all bird species present. Higher values of conservation index were associated with higher local densities of globally more rare and more threatened species. 3. Conservation index and species diversity were correlated negatively across hypothetical landscapes composed of different proportions of the five habitats. Therefore, a management trade-off existed between conservation index and species diversity because landscapes that maximized species diversity differed from landscapes that maximized conservation index. 4. A landscape of 50% open, 22% savanna, 15% scrub and 13% forest was predicted to represent a compromise at which conservation index and species diversity reached the same percentage of their maxima. In contrast, the current landscape is dominated by forest. 5. Synthesis and applications. We quantified the trade-off between two potential aspects of a landscape's conservation value for birds - the landscape's ability to promote avian species diversity and the landscape's use by threatened avian species. This quantification allowed us to evaluate the ability of different landscape compositions to achieve preferable trade-off compromises, such as maximizing diversity for a given level of landscape use by threatened species. Managers can use these trade-off results to determine which landscape compositions are associated with particular conservation and management priorities.

Journal of Applied Ecology↗

USGS2024

Clustering and unconstrained ordination with Dirichlet process mixture models

Assessment of similarity in species composition or abundance across sampled locations is a common goal in multi-species monitoring programs. Existing ordination techniques provide a framework for clustering sample locations based on species composition by projecting high-dimensional community data into a low-dimensional, latent ecological gradient representing species composition. However, these techniques require specification of the number of distinct ecological communities present in the latent space, which can be difficult to determine in advance. We develop an ordination model capable of simultaneous clustering and ordination that allows for estimation of the number of clusters present in the latent ecological gradient. This model draws latent coordinates for each sample location from a Dirichlet process mixture model, affording researchers with probabilistic statements about the number of clusters present in the latent ecological gradient. The model is compared to existing methods for simultaneous clustering and ordination via simulation and applied to two empirical datasets; JAGS code to fit the proposed model is provided in an appendix. The first dataset concerns presence-absence records of fish in the Doubs river in eastern France and the second dataset describes presence-absence records of plant species in Craters of the Moon National Monument and Preserve (CRMO) in Idaho, USA. Results from both analyses align with existing ecological gradients at each location. Development of the Dirichlet process ordination model provides wildlife managers with data-driven inferences about the number of distinct communities present across monitored locations, allowing for more cost-effective monitoring and reliable decision-making for conservation management.

Methods in Ecology and Evolution↗

USGS2019

Genetic tagging in the Anthropocene: Scaling ecology from alleles to ecosystems

The Anthropocene is an era of marked human impact on the world. Quantifying these impacts 51 has become central to understanding the dynamics of coupled human-natural systems, resource52 dependent livelihoods, and biodiversity conservation. Ecologists are facing growing pressure to 53 quantify the size, distribution, and trajectory of wild populations in a cost-effective and socially54 acceptable manner. Genetic tagging, combined with modern computational and genetic analyses, 55 is an under-utilized tool to meet this demand, especially for wide-ranging, elusive, sensitive, and 56 low-density species. Genetic tagging studies are now revealing unprecedented insight into the 57 mechanisms that control the density, trajectory, connectivity and human-wildlife conflict for 58 populations over vast spatial scales. Here we outline the application of, and ecological inferences 59 from, new analytical techniques applied to genetically-tagged individuals, contrast this approach 60 with conventional methods, and describe how genetic tagging can be better applied to address 61 outstanding questions in ecology. We provide example analyses using a long-term genetic 62 tagging dataset of grizzly bears in the Canadian Rockies. The genetic tagging toolbox is a 63 powerful and overlooked ensemble that ecologists and conservation biologists can leverage to 64 generate evidence and meet the challenges of the Anthropocene.

Ecological Applications↗

USGS2026

Quantifying avian resilience to habitat change to support conservation decision-making

Habitat loss and degradation are two of the main drivers of contemporary avian population declines. Wildlife managers are increasingly advocating for tools that provide decision support to set priorities for restoration or conservation efficiently. We demonstrate how to derive two species-specific management and resilience metrics: the greatest management impact point (GMIP) and the ecological resilience threshold (RT). The GMIP indicates the amount of environmental change in a landscape where habitat improvements are expected to have the greatest impact on species’ occurrence. The RT represents the amount of environmental change in a landscape that a species can tolerate before the steepest change in occupancy is expected to begin. We estimate species-specific metrics using the amount of uncharacteristic exotic vegetation as an index of environmental change, and demonstrate how multispecies patterns may suggest potential management strategies. We estimated occupancy models using 5 years of multispecies avian detection data from the Integrated Monitoring in Bird Conservation Regions program in the State of Utah, USA (hereafter, Utah). Based on the estimated relationship between species’ occupancy and amounts of uncharacteristic exotic vegetation, we derive RT and GMIP scores for 61 species breeding in Utah. We found wide interspecific variation in resilience to amounts of exotic vegetation, with species generally clustering at extreme values. Our results demonstrate that birds in Utah appear more resilient to amounts of uncharacteristic exotic vegetation at coarser spatial resolution, showing greater variance and lower average RTs at finer spatial resolution. Species that are not fully resilient to the range of uncharacteristic exotic vegetation observed in this study are expected to respond most strongly, on average, to management actions in landscapes with high levels of exotic vegetation; however, early detection and rapid response is likely the most effective strategy. Quantified across many species, these metrics can be used to identify and prioritize landscapes where current environmental conditions could be maintained to avoid the greatest species’ declines, or which maximize expected biodiversity returns on investment in environmental restoration. Managers can consider either focal species’ resilience for tailored conservation planning or summarize species resilience to create efficient management plans that maximize outcomes for multiple species.

Utah↗

USGS2015

Book Reivew: A chance for lasting survival: Ecology and behavior of wild giant pandas

“If we watch species going extinct in front of us, how useful is that we publish 100 or even 1,000 papers by studying them?” (p. 330). This quote from senior author Pan Wenshi captures an important essence of this book. A translation of a 2001 monograph originally published in Chinese, this volume details the findings of a 15-year research program in the Qinling Mountains by Wenshi and his students. Starting in 1984, this Chinese research team from Peking University was only the second to study free-ranging pandas. This is the remarkable journey of a devoted group of field researchers who helped changed the course of giant panda conservation, events that few conservationists outside of China have been aware of until now. Review info: A chance for lasting survival: Ecology and behavior of wild giant pandas. By Pan Wenshi, Lü Zhi, Zhu Xiaojian, Wang Dajun, Wang Hao, Long Yu, Fu Dali, and Zhou Xin; edited by, William J. McShea, Richard B. Harris, David L. Garshelis, and Wang Dajun, 2014. ISBN: 978-1-935623-17-5, 349pp.

The Quarterly Review of Biology↗

USGS2015

Global change and conservation triage on National Wildlife Refuges

National Wildlife Refuges (NWRs) in the United States play an important role in the adaptation of social-ecological systems to climate change, land-use change, and other global-change processes. Coastal refuges are already experiencing threats from sea-level rise and other change processes that are largely beyond their ability to influence, while at the same time facing tighter budgets and reduced staff. We engaged in workshops with NWR managers along the U.S. Atlantic coast to understand the problems they face from global-change processes and began a multidisciplinary collaboration to use decision science to help address them. We are applying a values-focused approach to base management decisions on the resource objectives of land managers, as well as those of stakeholders who may benefit from the goods and services produced by a refuge. Two insights that emerged from our workshops were a conspicuous mismatch between the scale at which management can influence outcomes and the scale of environmental processes, and the need to consider objectives related to ecosystem goods and services that traditionally have not been explicitly considered by refuges (e.g., protection from storm surge). The broadening of objectives complicates the decision-making process, but also provides opportunities for collaboration with stakeholders who may have agendas different from those of the refuge, as well as an opportunity for addressing problems across scales. From a practical perspective, we recognized the need to (1) efficiently allocate limited staff time and budgets for short-term management of existing programs and resources under the current refuge design and (2) develop long-term priorities for acquiring or protecting new land/habitat to supplement or replace the existing refuge footprint and thus sustain refuge values as the system evolves over time. Structuring the decision-making problem in this manner facilitated a better understanding of the issues of scale and suggested that a long-term solution will require a significant reassessment of objectives to better reflect the comprehensive values of refuges to society. We discuss some future considerations to integrate these two problems into a single framework by developing novel optimization approaches for dynamic problems that account for uncertainty in future conditions.

Ecology and Society↗

USGS2000

Cassin's Sparrow (Aimophila cassinii) status assessment and conservation plan

Executive Summary Cassin’s Sparrow ( Aimophila cassinii ) is a grassland species endemic to the southwestern U.S. and northern Mexico. Its behavior and ecology have been shaped by these arid ecosystems and the health of its populations is dependent on the availability of grasslands that contain a shrub component. Populations of many grassland birds have experienced dramatic declines due to the loss and deterioration of grassland habitats, and there has been concern about the trends in Cassin’s Sparrow populations. Without better information about population trends, ecology, and effects of management activities, and without a stronger emphasis on grassland management, Cassin’s Sparrows and other grassland species may continue to experience declines. Little information exists about historic Cassin’s Sparrow population levels, and current population estimates for states in the breeding range are unknown. Significant survey-wide declines are documented by the Breeding Bird Survey (BBS) between 1966 and 1996. However, closer examination of these data suggest that the survey-wide trends are driven by population declines in the Edwards Plateau and South Texas Brushlands in Texas. No other areas within the core of its range or on the periphery show consistent, significant trends. In fact, there is consensus that in the core of its range in New Mexico Cassin’s Sparrow remains the most abundant breeding bird in grasslands with a shrub component. Understanding of population patterns in this species is complicated by large yearly fluctuations in distribution and numbers at any particular location, apparently in response to precipitation. This is particularly obvious in the periphery of its range. These dramatic fluctuations have hampered a clear assessment of population status, and our understanding has been confounded by the fact that the timing of BBS data collection does not always coincide with the peak breeding season of this species. The lack of information about the Cassin’s Sparrow’s status, ecology, and response to management activities, and the apparent declines indicated by BBS data, have been cause for concern. Habitat disturbance and degradation, mainly due to grazing and rangeland management practices such as shrub control, fire management, and planting of exotics, pose threats to Cassin’s Sparrow populations, as does habitat conversion through suburban development and agriculture. There is evidence that heavy grazing negatively affects populations, but the information is primarily available from the southwestern portion of its range (Arizona) and may not be applicable throughout the Cassin’s Sparrow’s entire range. Any management practice that results in complete removal of the shrub component, or loss of grass cover and an increase in shrub density beyond a threshold preferred by the species, also poses a threat. Lack of standardized or coordinated studies of Cassin’s Sparrow ecology and response to management practices in different geographic portions of its range has made it difficult to assess its status and make specific management recommendations. Limited data are available from the wintering grounds, and from its range (both breeding and wintering) in Mexico. The greatest needs are for determining of the causes of significant declines where they occur, determining of the effects of various management activities on Cassin’s Sparrow throughout its range, improved assessments of population and trends, and a better understanding of the annual population and distribution dynamics of this species, which shows such dramatic annual distributional fluctuations.

Wyoming, Nebraska, Kansas, Oklahoma,Texas, New Mex↗

USGS2023

Gains and gaps in knowledge surrounding freshwater mollusk ecosystem services

Ecosystems provide essential services to people including food, water, climate regulation, and aesthetic experiences. Biodiversity can enhance and stabilize ecosystem function and the resulting services natural systems provide. Freshwater mollusks are a diverse group that provide a variety of ecosystem services through their feeding habits (e.g., filter feeding, grazing), top-down and bottom-up effects on food webs, provisioning of habitat, use as a food resource by people, and cultural importance. Research focused on quantifying the direct and indirect ways mollusks influence ecosystem services may help inform policy makers and the public about the value of mollusk communities to society. The Freshwater Mollusk Conservation Society highlighted the need to evaluate mollusk ecosystem services in their 2016 National Strategy for the Conservation of Native Freshwater Mollusks, and, while significant progress has been made, considerable work remains across the research, management, and outreach communities. We briefly review the global status of native freshwater mollusks, assess the current state of knowledge regarding their ecosystem services, and highlight recent advances and knowledge gaps to guide further research and conservation actions. Our intention is to provide ecologists, conservationists, economists, and social scientists with information to improve science-based consideration of the social, ecological, and economic value of mollusk communities to healthy aquatic systems.

Freshwater Mollusk Biology and Conservation↗

USGS2014

Habitat prioritization across large landscapes, multiple seasons, and novel areas: an example using greater sage-grouse in Wyoming

Animal habitat selection is an important and expansive area of research in ecology. In particular, the study of habitat selection is critical in habitat prioritization efforts for species of conservation concern. Landscape planning for species is happening at ever-increasing extents because of the appreciation for the role of landscape-scale patterns in species persistence coupled to improved datasets for species and habitats, and the expanding and intensifying footprint of human land uses on the landscape. We present a large-scale collaborative effort to develop habitat selection models across large landscapes and multiple seasons for prioritizing habitat for a species of conservation concern. Greater sage-grouse ( Centrocercus urophasianus , hereafter sage-grouse) occur in western semi-arid landscapes in North America. Range-wide population declines of this species have been documented, and it is currently considered as “warranted but precluded” from listing under the United States Endangered Species Act. Wyoming is predicted to remain a stronghold for sage-grouse populations and contains approximately 37% of remaining birds. We compiled location data from 14 unique radiotelemetry studies (data collected 1994–2010) and habitat data from high-quality, biologically relevant, geographic information system (GIS) layers across Wyoming. We developed habitat selection models for greater sage-grouse across Wyoming for 3 distinct life stages: 1) nesting, 2) summer, and 3) winter. We developed patch and landscape models across 4 extents, producing statewide and regional (southwest, central, northeast) models for Wyoming. Habitat selection varied among regions and seasons, yet preferred habitat attributes generally matched the extensive literature on sage-grouse seasonal habitat requirements. Across seasons and regions, birds preferred areas with greater percentage sagebrush cover and avoided paved roads, agriculture, and forested areas. Birds consistently preferred areas with higher precipitation in the summer and avoided rugged terrain in the winter. Selection for sagebrush cover varied regionally with stronger selection in the Northeast region, likely because of limited availability, whereas avoidance of paved roads was fairly consistent across regions. We chose resource selection function (RSF) thresholds for each model set (seasonal × regional combination) that delineated important seasonal habitats for sage-grouse. Each model set showed good validation and discriminatory capabilities within study-site boundaries. We applied the nesting-season models to a novel area not included in model development. The percentage of independent nest locations that fell directly within identified important habitat was not overly impressive in the novel area (49%); however, including a 500-m buffer around important habitat captured 98% of independent nest locations within the novel area. We also used leks and associated peak male counts as a proxy for nesting habitat outside of the study sites used to develop the models. A 1.5-km buffer around the important nesting habitat boundaries included 77% of males counted at leks in Wyoming outside of the study sites. Data were not available to quantitatively test the performance of the summer and winter models outside our study sites. The collection of models presented here represents large-scale resource-management planning tools that are a significant advancement to previous tools in terms of spatial and temporal resolution.

Wyoming↗