US Endangered Research Articles

Erratum to: "Is the Red Wolf a Listable Unit Under the US Endangered Species Act?"

Erratum to: "Is the Red Wolf a Listable Unit Under the US Endangered Species Act?"

Stability, persistence and habitat associations of the pearl darter Percina aurora in the Pascagoula River System, southeastern USA

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 36:99-109 (2018) - DOI: https://doi.org/10.3354/esr00897 Stability, persistence and habitat associations of the pearl darter Percina aurora in the Pascagoula River System, southeastern USA Scott R. Clark1,4,*, William T. Slack2, Brian R. Kreiser1, Jacob F. Schaefer1, Mark A. Dugo3 1Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi 39406, USA 2US Army Engineer Research and Development Center, Environmental Laboratory EEA, Vicksburg, Mississippi 39180, USA 3Mississippi Valley State University, Department of Natural Sciences and Environmental Health, Itta Bena, Mississippi 38941, USA 4Present address: Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA *Corresponding author: scottrclark2@gmail.com ABSTRACT: The southeastern United States represents one of the richest collections of aquatic biodiversity worldwide; however, many of these taxa are under an increasing threat of imperilment, local extirpation, or extinction. The pearl darter Percina aurora is a small-bodied freshwater fish endemic to the Pearl and Pascagoula river systems of Mississippi and Louisiana (USA). The last collected specimen from the Pearl River drainage was taken in 1973, and it now appears that populations in this system are likely extirpated. This reduced the historical range of this species by approximately 50%, ultimately resulting in federal protection under the US Endangered Species Act in 2017. To better understand the current distribution and general biology of extant populations, we analyzed data collected from a series of surveys conducted in the Pascagoula River drainage from 2000 to 2016. Pearl darters were captured at relatively low abundance (2.4 ± 4.0 ind. per collection) from 57% of 308 collections. We identified strong relationships between local habitat variables and occurrence and catch-per-unit-effort (CPUE) of pearl darters. Pearl darters were frequently encountered and in greater abundance in depositional areas characterized by low-velocity habitats and finer substrates. Patterns of occurrence and CPUE were spatiotemporally variable across years; however, repeated collections from a subset of localities collected across a decade or more indicated long-term persistence and stability, suggesting population resilience throughout the Pascagoula River drainage. KEY WORDS: Pearl darter · Pascagoula River · Historical distribution · Habitat associations Full text in pdf format Supplementary material PreviousNextCite this article as: Clark SR, Slack WT, Kreiser BR, Schaefer JF, Dugo MA (2018) Stability, persistence and habitat associations of the pearl darter Percina aurora in the Pascagoula River System, southeastern USA. Endang Species Res 36:99-109. https://doi.org/10.3354/esr00897 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 36. Online publication date: June 13, 2018 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2018 Inter-Research.

Is the Red Wolf a Listable Unit Under the US Endangered Species Act?

Defining units that can be afforded legal protection is a crucial, albeit challenging, step in conservation planning. As we illustrate with a case study of the red wolf (Canis rufus) from the southeastern United States, this step is especially complex when the evolutionary history of the focal taxon is uncertain. The US Endangered Species Act (ESA) allows listing of species, subspecies, or Distinct Population Segments (DPSs) of vertebrates. Red wolves were listed as an endangered species in 1973, and their status remains precarious. However, some recent genetic studies suggest that red wolves are part of a small wolf species (C. lycaon) specialized for heavily forested habitats of eastern North America, whereas other authors suggest that red wolves arose, perhaps within the last ~400 years, through hybridization between gray wolves (C. lupus) and coyotes (C. latrans). Using published genetic, morphological, behavioral, and ecological data, we evaluated whether each evolutionary hypothesis would lead to a listable unit for red wolves. Although the potential hybrid origin of red wolves, combined with abundant evidence for recent hybridization with coyotes, raises questions about status as a separate species or subspecies, we conclude that under any proposed evolutionary scenario red wolves meet both criteria to be considered a DPS: they are Discrete compared with other conspecific populations, and they are Significant to the taxon to which they belong. As population-level units can qualify for legal protection under endangered-species legislation in many countries throughout the world, this general approach could potentially be applied more broadly.

Natural re-colonization and admixture of wolves (Canis lupus) in the US Pacific Northwest: challenges for the protection and management of rare and endangered taxa.

Admixture resulting from natural dispersal processes can potentially generate novel phenotypic variation that may facilitate persistence in changing environments or result in the loss of population-specific adaptations. Yet, under the US Endangered Species Act, policy is limited for management of individuals whose ancestry includes a protected taxon; therefore, they are generally not protected under the Act. This issue is exemplified by the recently re-established grey wolves of the Pacific Northwest states of Washington and Oregon, USA. This population was likely founded by two phenotypically and genetically distinct wolf ecotypes: Northern Rocky Mountain (NRM) forest and coastal rainforest. The latter is considered potentially threatened in southeast Alaska and thus the source of migrants may affect plans for their protection. To assess the genetic source of the re-established population, we sequenced a ~ 300 bp portion of the mitochondrial control region and ~ 5 Mbp of the nuclear genome. Genetic analysis revealed that the Washington wolves share ancestry with both wolf ecotypes, whereas the Oregon population shares ancestry with NRM forest wolves only. Using ecological niche modelling, we found that the Pacific Northwest states contain environments suitable for each ecotype, with wolf packs established in both environmental types. Continued migration from coastal rainforest and NRM forest source populations may increase the genetic diversity of the Pacific Northwest population. However, this admixed population challenges traditional management regimes given that admixture occurs between an adaptively distinct ecotype and a more abundant reintroduced interior form. Our results emphasize the need for a more precise US policy to address the general problem of admixture in the management of endangered species, subspecies, and distinct population segments.

Isolation, characterization and molecular identification of a novel aquareovirus that infects endangered fountain darter Etheostoma fonticola.

The fountain darter Etheostoma fonticola (FOD) is a federally endangered fish listed under the US Endangered Species Act. Here, we identified and characterized a novel aquareovirus isolated from wild fountain darters inhabiting the San Marcos River. This virus was propagated in Chinook salmon embryo (CHSE)-214, rainbow trout gonad-2 and fathead minnow cells at 15°C. The epithelioma papulosum cyprini cell line was refractory at all temperatures evaluated. High throughput sequencing technologies facilitated the complete genome sequencing of this virus utilizing ribosomal RNA-depleted RNA extracted from infected CHSE-214 cells. Conventional PCR primer sets were developed for the detection and confirmation of this virus to assist diagnostic screening methods. Phylogenetic analysis suggests this virus belongs to the Aquareovirus A genus. This research provides requisite initial data critical to support hatchery and refugia biosecurity measures for this endangered species.

Cattle grazing and fish recovery on US federal lands: can social–ecological systems science help?

In the western US, grazing management on federal lands containing habitat for fish species listed under the US Endangered Species Act (ESA) has sparked social conflict and litigation for decades. To date, the problem has been addressed through a top‐down environmental governance system, but rangeland managers and grazing permittees now believe there is a need for more innovative management strategies. This article explores how social–ecological systems (SES) science can address rangeland management challenges associated with the survival and recovery of ESA‐listed fish species on federal lands where cattle grazing is a dominant type of land use. We focus on the Blue Mountains of eastern Oregon, where the Mountain Social Ecological Observatory Network's Blue Mountains Working Group is collaborating with diverse stakeholders to develop and test a novel grazing system designed to reduce the impact of cattle on riparian areas using an SES science approach. Although not a complete solution, SES science holds promise for improving rangeland management.

Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 35:181-193 (2018) - DOI: https://doi.org/10.3354/esr00885 Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles Shawn K. K. Murakawa1,*, Melissa L. Snover2 1NOAA Fisheries, Pacific Islands Fisheries Science Center, 1845 Wasp Boulevard, Building 176, Honolulu, Hawaii 96818, USA 2Population Ecology Services, PO Box 3673, Pago Pago, American Samoa 96799, USA *Corresponding author: shawn.murakawa@noaa.gov ABSTRACT: The Hawaiian green sea turtle Chelonia mydas population has steadily increased since its protection under the US Endangered Species Act of 1978. However, an understanding of their recovery status is stymied by lack of certainty regarding the population age structure. Based on the observed slow growth rates of juveniles, current assessments place age at first reproduction in Hawaiian green sea turtles at 35-40 yr, although a recent study suggests 23 yr for this population. It is possible that somatic growth dynamics such as growth spurts have been missed by traditional mark-recapture studies. Skeletochronology provides annual longitudinal data on growth rates of marine turtles, allowing for the detection of rare but potentially important growth spurts. The present study uses skeletochronology to estimate growth rates and detect the frequency of growth spurts in 30-90 cm straight carapace length (SCL) Hawaiian green sea turtles. We found that growth spurts occurred throughout the life span, but peaked for males from 50 to 59.9 cm SCL and for females from 70 to 79.9 cm SCL. The growth rates were binned into 10 cm SCL size class bins, and 4 methods were used to estimate the mean growth rate for each bin. We found that mean growth rates overestimated life-stage durations for each of the methods, although the expectation of the lognormal distribution gave the least biased results. Our study suggests that infrequent growth spurts are not represented in mean growth rate statistics but that these spurts likely result in faster lifetime growth rates and lower age at first reproduction than has been estimated using traditional methods. KEY WORDS: Chelonia mydas · Age at first reproduction · Growth spurts · Humeri · Skeletochronology Full text in pdf format PreviousCite this article as: Murakawa SKK, Snover ML (2018) Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles. Endang Species Res 35:181-193. https://doi.org/10.3354/esr00885 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 35. Online publication date: April 27, 2018 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2018 Inter-Research.

Exploitation of endangered mammals in the United States

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 34:185-190 (2017) - DOI: https://doi.org/10.3354/esr00850 NOTEExploitation of endangered mammals in the United States Christian J. Rivera* Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY 10027, USA *Corresponding author: cjrivera@alumni.princeton.edu ABSTRACT: Overexploitation is a pervasive threat to mammal species worldwide and ranks second to habitat destruction as the major cause of their decline in the United States. Fine-scale analyses and quantitative studies on the threats to endangered species are lacking, which can undermine conservation and recovery efforts. Using threats data gathered from official Federal Register notices and recovery plans from the US Fish and Wildlife Service and National Marine Fisheries Service, I quantified the extent to which anthropogenic exploitation threatens the mammal species, subspecies, and populations that are protected under the US Endangered Species Act. Of the federally endangered mammal species in the United States, 65% are threatened by intentional or incidental exploitation by humans, including all endangered ungulates and whales. The most prevalent threats to endangered mammals are harvesting for raw materials (53%), incidental shooting, trapping, and poisoning (37%), and persecution (32%). A significantly higher proportion of marine than terrestrial mammals are threatened by exploitation (96 vs. 57%; χ2 = 10.3, df = 1, p = 0.001). The results from this fine-scale analysis can be used to understand the relative importance of threats in order to guide the distribution of conservation resources and develop context-specific conservation strategies. KEY WORDS: Endangered mammals · Exploitation · Overexploitation · United States Endangered Species Act · Threats · National Marine Fisheries Service · US Fish and Wildlife Service Full text in pdf format PreviousNextCite this article as: Rivera CJ (2017) Exploitation of endangered mammals in the United States. Endang Species Res 34:185-190. https://doi.org/10.3354/esr00850 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 34. Online publication date: September 05, 2017 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2017 Inter-Research.

Keep Burning Coal or the Manatee Gets It: Rendering the Carbon Economy Invisible through Endangered Species Protection

AbstractAs ever expanding accretions of human industrial and residential development pave over endangered Florida manatees’ warm water springs winter habitat, more than half of the manatees have come to depend upon fossil fuel‐burning power plant hot water effluent channels for survival. In an effort to save these manatees, environmental activists have leveraged the US Endangered Species Act to protect the effluent streams and, by extension, have enshrined the power plants themselves as ecological saviors. This study interrogates the paradoxes within the resulting spatio‐legal regime. Recognizing the problematic human/nature binary at the heart of dominant Western practices, our study suggests spatial and legal regimes do not simply reify and reproduce this binary but also produce invisible ecocultural spaces that are essential to prop up an inherently unstable, illusory, and ultimately destructive definition of human existence.

Influence of dispersal processes on the global dynamics of Emperor penguin, a species threatened by climate change

Species endangered by rapid climate change may persist by tracking their optimal habitat; this depends on their dispersal characteristics. The Emperor penguin (EP) is an Antarctic seabird threatened by future sea ice change, currently under consideration for listing under the US Endangered Species Act. Indeed, a climate-dependent-demographic model without dispersion projects that many EP colonies will decline by more than 50% from their current size by 2100, resulting in a dramatic global population decline. Here we assess whether or not dispersion could act as an ecological rescue, i.e. reverse the anticipated global population decline projected by a model without dispersion. To do so, we integrate detailed dispersal processes in a metapopulation model—specifically, dispersal stages, dispersal distance, habitat structure, informed dispersal behaviors, and density-dependent dispersion rates. For EP, relative to a scenario without dispersion, dispersal can either offset or accelerate climate driven population declines; dispersal may increase the global population by up to 31% or decrease it by 65%, depending on the rate of emigration and distance individuals disperse. By developing simpler theoretical models, we demonstrate that the global population dynamic depends on the global landscape quality. In addition, the interaction among dispersal processes - dispersion rates, dispersal distance, and dispersal decisions - that influence landscape occupancy, impacts the global population dynamics. Our analyses bound the impact of between-colony emigration on global population size, and provide intuition as to the direction of population change depending on the EP dispersal characteristics. Our general model is flexible such that multiple dispersal scenarios could be implemented for a wide range of species to improve our understanding and predictions of species persistence under future global change.

The Agassiz's desert tortoise genome provides a resource for the conservation of a threatened species.

Agassiz’s desert tortoise (Gopherus agassizii) is a long-lived species native to the Mojave Desert and is listed as threatened under the US Endangered Species Act. To aid conservation efforts for preserving the genetic diversity of this species, we generated a whole genome reference sequence with an annotation based on deep transcriptome sequences of adult skeletal muscle, lung, brain, and blood. The draft genome assembly for G. agassizii has a scaffold N50 length of 252 kbp and a total length of 2.4 Gbp. Genome annotation reveals 20,172 protein-coding genes in the G. agassizii assembly, and that gene structure is more similar to chicken than other turtles. We provide a series of comparative analyses demonstrating (1) that turtles are among the slowest-evolving genome-enabled reptiles, (2) amino acid changes in genes controlling desert tortoise traits such as shell development, longevity and osmoregulation, and (3) fixed variants across the Gopherus species complex in genes related to desert adaptations, including circadian rhythm and innate immune response. This G. agassizii genome reference and annotation is the first such resource for any tortoise, and will serve as a foundation for future analysis of the genetic basis of adaptations to the desert environment, allow for investigation into genomic factors affecting tortoise health, disease and longevity, and serve as a valuable resource for additional studies in this species complex.

Developing population models: A systematic approach for pesticide risk assessment using herbaceous plants as an example

Population models are used as tools in species management and conservation and are increasingly recognized as important tools in pesticide risk assessments. A wide variety of population model applications and resources on modeling techniques, evaluation and documentation can be found in the literature. In this paper, we add to these resources by introducing a systematic, transparent approach to developing population models. The decision guide that we propose is intended to help model developers systematically address data availability for their purpose and the steps that need to be taken in any model development. The resulting conceptual model includes the necessary complexity to address the model purpose on the basis of current understanding and available data.We provide specific guidance for the development of population models for herbaceous plant species in pesticide risk assessment and demonstrate the approach with an example of a conceptual model developed following the decision guide for herbicide risk assessment of Mead's milkweed (Asclepias meadii), a species listed as threatened under the US Endangered Species Act. The decision guide specific to herbaceous plants demonstrates the details, but the general approach can be adapted for other species groups and management objectives.Population models provide a tool to link population-level dynamics, species and habitat characteristics as well as information about stressors in a single approach. Developing such models in a systematic, transparent way will increase their applicability and credibility, reduce development efforts, and result in models that are readily available for use in species management and risk assessments.

Genetic and individual assignment of tetraploid green sturgeon with SNP assay data

Polyploid organisms pose substantial obstacles to genetic analysis, as molecular assay data are usually difficult to evaluate in a Mendelian framework. Green sturgeon (Acipenser medirostris) is a tetraploid species and is facing significant conservation challenges, including bycatch in ocean fisheries. We present here novel molecular genetic assays and analytical methodology for green sturgeon that allow discrimination of fish from the two visually indistinguishable distinct population segments (DPSs), and also provide individual-specific genetic tags. We show how the relative fluorescence intensity data from a standard quantitative PCR assay, designed for a biallelic single nucleotide polymorphism, can be grouped into “genotype categories” using standard analytical software and post-processing manipulation. We then show how these genotype category data can be used to discriminate green sturgeon from the southern DPS, which is protected under the US Endangered Species Act, and the northern DPS, which is not. We also show how these data can be used to reliably identify individual green sturgeon, and can therefore be used in capture/recapture analyses. Both types of identification are extremely accurate even when fewer than half of the assays are successfully called. We then apply these new techniques to show that proportions of the two green sturgeon DPSs are extremely different in the two major fishery areas where they are encountered as bycatch. While these assays and methods do not provide data that can be used in pedigree-based analyses, they are an important advance in the application of genetic analysis to conservation and management of polyploid organisms.

Private Sector Conservation Investments under the Endangered Species Act: A Guide to Return on Investment Analysis

The US Endangered Species Act (ESA) protects imperiled species by prohibiting harm to listed species and their habitat. Over the last 20 years, the US Fish and Wildlife Service and National Marine Fisheries Service have developed programs to increase management flexibility under the ESA and to encourage voluntary conservation actions by the private sector — above and beyond what is required for ESA compliance. These programs include Candidate Conservation Agreements, Safe Harbor Agreements, and a new Prelisting Conservation Policy, among others. Why would private landowners and firms voluntarily engage in proactive conservation efforts? We address that question by exploring the incentives created by ESA programs, using a return on investment (ROI) framework to identify the costs and benefits of participation. The paper is relevant to firms affected by current or potential species listings. It is also relevant to NGO and government conservation advocates interested in encouraging more conservation by the private sector. The analysis sheds light on factors likely to affect participation, programs’ likely effectiveness, ways to better target partnering or cost-share engagements with the private sector, and the design of future programs to achieve conservation goals.

Listing Foreign Species under the Endangered Species Act: A Primer for Conservation Biologists

Nearly 30% of the species currently listed under the US Endangered Species Act (ESA) neither live nor migrate through the United States or the territories under its jurisdiction. Consequently, many of the protections afforded by the ESA, such as the development of species recovery plans and the requirement for federal consultation, are not applied to these “foreign listings.” Overlap between the ESA and other international legislation has created an idiosyncratic patchwork of protections for endangered foreign species, which is further complicated by court rulings that affect the administration of the law. This overview of the historical, legal, and administrative elements of the ESA as have been applied to foreign species aims to provide a straightforward guide for ecologists and conservation biologists on this complex legal issue. We discuss the potential advantages and disadvantages of foreign listings and raise important questions about the practical benefits of listing foreign species under the ESA.

Population assessment using multivariate time-series analysis: A case study of rockfishes in Puget Sound.

Estimating a population's growth rate and year‐to‐year variance is a key component of population viability analysis (PVA). However, standard PVA methods require time series of counts obtained using consistent survey methods over many years. In addition, it can be difficult to separate observation and process variance, which is critical for PVA. Time‐series analysis performed with multivariate autoregressive state‐space (MARSS) models is a flexible statistical framework that allows one to address many of these limitations. MARSS models allow one to combine surveys with different gears and across different sites for estimation of PVA parameters, and to implement replication, which reduces the variance‐separation problem and maximizes informational input for mean trend estimation. Even data that are fragmented with unknown error levels can be accommodated. We present a practical case study that illustrates MARSS analysis steps: data choice, model set‐up, model selection, and parameter estimation. Our case study is an analysis of the long‐term trends of rockfish in Puget Sound, Washington, based on citizen science scuba surveys, a fishery‐independent trawl survey, and recreational fishery surveys affected by bag‐limit reductions. The best‐supported models indicated that the recreational and trawl surveys tracked different, temporally independent assemblages that declined at similar rates (an average of −3.8% to −3.9% per year). The scuba survey tracked a separate increasing and temporally independent assemblage (an average of 4.1% per year). Three rockfishes (bocaccio, canary, and yelloweye) are listed in Puget Sound under the US Endangered Species Act (ESA). These species are associated with deep water, which the recreational and trawl surveys sample better than the scuba survey. All three ESA‐listed rockfishes declined as a proportion of recreational catch between the 1970s and 2010s, suggesting that they experienced similar or more severe reductions in abundance than the 3.8–3.9% per year declines that were estimated for rockfish populations sampled by the recreational and trawl surveys.

Critical habitat designation for Canadian listed species: Slow, biased, and incomplete

Although endangered species legislation can be a powerful tool for protecting species, such laws are only as good as their implementation. Under the Canadian Species at Risk Act, Critical Habitat is designated in a Recovery Strategy as the habitat required for the recovery or survival of a listed species. We examined the finalized Recovery Strategies for 234 species and we found poor implementation of Critical Habitat designation for Canadian species. Most listed species (62.9%) lack Critical Habitat; only 11.8% have full Critical Habitat. Many species with Critical habitat obtained it years later than the statutory requirements. Designation is biased taxonomically, by major habitat type, and by lead agency. These results echo findings from the US Endangered Species Act, despite differences between the laws in when designation is supposed to occur. Additional funding and expertise would likely help reduce these delays. We also strongly encourage designation even in the face of incomplete information because of the significant negative consequences that can result from failure to protect the habitat of species at risk of extinction.

Acute sensitivity of the vernal pool fairy shrimp, Branchinecta lynchi (Anostraca; Branchinectidae), and surrogate species to 10 chemicals.

Vernal pool fairy shrimp, Branchinecta lynchi, (Branchiopoda; Anostraca) and other fairy shrimp species have been listed as threatened or endangered under the US Endangered Species Act. Because few data exist about the sensitivity of Branchinecta spp. to toxic effects of contaminants, it is difficult to determine whether they are adequately protected by water quality criteria. A series of acute (24-h) lethality/immobilization tests was conducted with 3 species of fairy shrimp (B. lynchi, Branchinecta lindahli, and Thamnocephalus platyurus) and 10 chemicals with varying modes of toxic action: ammonia, potassium, chloride, sulfate, chromium(VI), copper, nickel, zinc, alachlor, and metolachlor. The same chemicals were tested in 48-h tests with other branchiopods (the cladocerans Daphnia magna and Ceriodaphnia dubia) and an amphipod (Hyalella azteca), and in 96-h tests with snails (Physa gyrina and Lymnaea stagnalis). Median effect concentrations (EC50s) for B. lynchi were strongly correlated (r2 = 0.975) with EC50s for the commercially available fairy shrimp species T. platyurus for most chemicals tested. Comparison of EC50s for fairy shrimp and EC50s for invertebrate taxa tested concurrently and with other published toxicity data indicated that fairy shrimp were relatively sensitive to potassium and several trace metals compared with other invertebrate taxa, although cladocerans, amphipods, and mussels had similar broad toxicant sensitivity. Interspecies correlation estimation models for predicting toxicity to fairy shrimp from surrogate species indicated that models with cladocerans and freshwater mussels as surrogates produced the best predictions of the sensitivity of fairy shrimp to contaminants. The results of these studies indicate that fairy shrimp are relatively sensitive to a range of toxicants, but Endangered Species Act-listed fairy shrimp of the genus Branchinecta were not consistently more sensitive than other fairy shrimp taxa. Environ Toxicol Chem 2017;36:797-806. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Molecular systematics of the critically-endangered North American spinymussels (Unionidae: Elliptio and Pleurobema) and description of Parvaspina gen. nov.

Despite being common in numerous marine bivalve lineages, lateral spines are extremely rare among freshwater bivalves (Bivalvia: Unionidae), with only three known species characterized by the presence of spines: Elliptio spinosa, Elliptio steinstansana, and Pleurobema collina. All three taxa are endemic to the Atlantic Slope of southeastern North America, critically endangered, and protected by the US Endangered Species Act. Currently, these species are recognized in two genera and remain a source of considerable taxonomic confusion. Because spines are rare in freshwater mussels and restricted to a small region of North America, we hypothesized that spinymussels represent a monophyletic group. We sequenced two mtDNA gene fragments (COI and ND1) and a fragment of the nuclear ITS-1 locus from >70 specimens. Bayesian and maximum-likelihood phylogenetic reconstructions suggest that the spinymussels do not comprise a monophyletic group. Elliptio steinstansana is sister to P. collina, forming a monophyletic clade that was estimated to have diverged from its most recent ancestor in the late Miocene and is distinct from both Elliptio and Pleurobema; we describe a new genus (Parvaspina gen. nov.) to reflect this relationship. Additionally, E. spinosa forms a monophyletic clade that diverged from members of the core Elliptio lineage in the mid-Pliocene. Furthermore, E. spinosa is genetically divergent from the other spinymussel species, suggesting that spines, while extremely rare in freshwater mussels worldwide, may have evolved independently in two bivalve lineages. Recognizing the genetic distinctiveness and inter-generic relationships of the spinymussels is an important first step towards effectively managing these imperiled species and lays the groundwork for future conservation genetics studies.

The importance of seasonal resource selection when managing a threatened species: targeting conservation actions within critical habitat designations for the Gunnison sage-grouse

Context The ability to identify priority habitat is critical for species of conservation concern. The designation of critical habitat under the US Endangered Species Act 1973 identifies areas occupied by the species that are important for conservation and may need special management or protection. However, relatively few species’ critical habitats designations incorporate habitat suitability models or seasonal specificity, even when that information exists. Gunnison sage-grouse (GUSG) have declined substantially from their historical range and were listed as threatened by the US Fish and Wildlife Service (USFWS) in November 2014. GUSG are distributed into eight isolated populations in Colorado and Utah, and one population, the Gunnison Basin (GB), has been the focus of much research. Aims To provide season-specific resource selection models to improve targeted conservation actions within the designated critical habitat in the GB. Methods We utilised radio-telemetry data from GUSG captured and monitored from 2004 to 2010. We were able to estimate resource selection models for the breeding (1 April–15 July) and summer (16 July–30 September) seasons in the GB using vegetation, topographical and anthropogenic variables. We compared the seasonal models with the existing critical habitat to investigate whether the more specific seasonal models helped identify priority habitat for GUSG. Key results The predictive surface for the breeding model indicated higher use of large areas of sagebrush, whereas the predictive surface for the summer model predicted use of more diverse habitats. The breeding and summer models (combined) matched the current critical habitat designation 68.5% of the time. We found that although the overall habitat was similar between the critical habitat designation and our combined models, the pattern and configuration of the habitat were very different. Conclusions These models highlight areas with favourable environmental variables and spatial juxtaposition to establish priority habitat within the critical habitat designated by USFWS. More seasonally specific resource selection models will assist in identifying specific areas within the critical habitat designation to concentrate habitat improvements, conservation and restoration within the GB. Implications This information can be used to provide insight into the patterns of seasonal habitat selection and can identify priority GUSG habitat to incorporate into critical habitat designation for targeted management actions.