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While predicting species status into the future is inherently uncertain, it is necessary to properly inform conservation decision-making. Using a triple loop stochastic simulation model with a population viability analysis, we projected populations of the northwestern and southwestern pond turtle (Actinemys marmorata and Actinemys pallida, respectively) to the end of the century. We integrated the future trajectories and demographic or population-level effects of three primary threats (drought, invasive bullfrogs, and habitat loss) into the predictive model. Extinction risk of both species increased into the future, with projected widespread declines in abundance and a consistent, negative population growth. By the end of the century, mean probability of extinction was 50 % for the northwestern pond turtle and 75 % for the southwestern pond turtle. The northwestern pond turtle exhibited a latitudinal trend, with southern population units at greater risk of extinction. The population growth rate of the northwestern pond turtle was sensitive to the threat of invasive bullfrogs, whereas drought most strongly influenced southwestern pond turtle growth rates. Future drought conditions will likely be more stochastic than modeled here, where projection methods were limited by the scale and congruency of drought information in pond turtle studies. The habitat loss threat was negligible for both species, although it is likely underestimated due to lack of relevant information on both its future trajectory and effect on vital rates. This work served as decision support science for the Species Status Assessment of the two species, and ultimately, the listing decision under the U.S. Endangered Species Act.

Conservation prioritization frameworks are used worldwide to identify species at greatest risk of extinction and to allocate limited resources across regions, species, and populations. Conservation prioritization can be impeded by ecological knowledge gaps and data deficiency, especially in freshwater species inhabiting highly complex aquatic ecosystems. Therefore, we developed a flexible approach that calculates a species' imperilment risk based on the conservation principles of resiliency, redundancy, and representation (i.e., the "three R's"). Our approach organizes data on species traits, distributions, population connectivity, and threats within a Bayesian belief network capable of predicting resiliency and redundancy within representative ecological settings. Empirical data and expert judgment inform the model to provide robust and repeatable risk assessments for rare and data‐deficient species. The model calculates resiliency at hierarchical spatial scales from distributional trends and population strength. Redundancy is estimated from the connectivity and quantities of extant populations. Resiliency, redundancy, and species' inherent vulnerability based on species traits collectively estimate extirpation risk within each unique ecological setting. Extirpation risks across ecological settings characterize representation and are aggregated to estimate global imperilment risk. We demonstrate the model's utility with Piebald Madtom (Noturus gladiator), a species petitioned for listing under the U.S. Endangered Species Act. Our results revealed that resiliency, redundancy, and extirpation risks can vary spatially across the species' range while identifying populations where additional sampling could disproportionally reduce uncertainty in estimated global imperilment risk. Our approach could standardize and expedite conservation status assessments, identify opportunities for early management intervention of at‐risk species and populations, and strategically reduce uncertainty by focusing monitoring and research on priority information gaps. [ABSTRACT FROM AUTHOR]

Multispecies risk assessments have developed within many international conservation programs, reflecting a widespread need for efficiency. Under the United States Endangered Species Act (ESA), multispecies assessments ultimately lead to species‐level listing decisions. Although this approach provides opportunities for improved efficiency, it also risks overwhelming or biasing the assessment process and would benefit from clear guidance for practitioners. We reviewed multispecies assessments conducted between 1993 and 2019 for ESA listing decisions to identify the ecological basis for combining species, the assessment approach used, and the policy factors influencing their efficacy. We identified 42 cases covering 359 species. Most assessments (81%) included two to five species, although the maximum was 82. A common theme involved grouping narrow endemics or habitat specialists based on taxonomic relatedness, similar distributions, and common threats to persistence. All assessments included a combined threats analysis, but few employed a common species' response model or expert elicitation process. Although ESA risk assessments are distinct from policy decisions, most assessments (50%) supported decisions that all species warranted endangered status. Available guidance has generally emphasized ecological similarity as the key attribute leading to successful multispecies assessments. The challenge with consistently selecting species based on qualitative proxies such as common distributions or threats to persistence is that ecological patterns and processes are scale dependent. Focusing instead on the assessment methods and their potential for bias and increased efficiency may provide a stronger basis for developing consistent and transparent guidance. [ABSTRACT FROM AUTHOR]

Proactive Conservation is a paradigm of natural resource management in the United States that encourages voluntary, collaborative efforts to restore species before they need to be protected through government regulations. This paradigm is widely used to conserve at-risk species today, and when used in conjunction with the Policy for Evaluation of Conservation Efforts (PECE), it allows for successful conservation actions to preclude listing of species under the Endangered Species Act (ESA). Despite the popularity of this paradigm, and recent flagship examples of its use (e.g., greater sage grouse, Centrocercus urophasianus), critical assessments of the outcomes of Proactive Conservation are lacking from the standpoint of species status and recovery metrics. Here, we provide such an evaluation, using the New England cottontail (Sylvilagus transitionalis), heralded as a success of Proactive Conservation efforts in the northeastern United States, as a case study. We review the history and current status of the species, based on the state of the science, in the context of the Conservation Initiative, and the 2015 PECE decision not to the list the species under the ESA. In addition to the impacts of the PECE decision on the New England cottontail conservation specifically, our review also evaluates the benefits and limits of the Proactive Conservation paradigm more broadly, and we make recommendations for its role in relation to ESA implementation for the future of at-risk species management. We find that the status and assurances for recovery under the PECE policy, presented at the time of the New England cottontail listing decision, were overly optimistic, and the status of the species has worsened in subsequent years. We suggest that use of PECE to avoid listing may occur because of the perception of the ESA as a punitive law and a misconception that it is a failure, although very few listed species have gone extinct. Redefining recovery to decouple it from delisting and instead link it to probability of persistence under recommended conservation measures would remove some of the stigma of listing, and it would strengthen the role of Species Status Assessments in endangered species conservation. [ABSTRACT FROM AUTHOR]

Abstract Multispecies risk assessments have developed within many international conservation programs, reflecting a widespread need for efficiency. Under the United States Endangered Species Act (ESA), multispecies assessments ultimately lead to species‐level listing decisions. Although this approach provides opportunities for improved efficiency, it also risks overwhelming or biasing the assessment process and would benefit from clear guidance for practitioners. We reviewed multispecies assessments conducted between 1993 and 2019 for ESA listing decisions to identify the ecological basis for combining species, the assessment approach used, and the policy factors influencing their efficacy. We identified 42 cases covering 359 species. Most assessments (81%) included two to five species, although the maximum was 82. A common theme involved grouping narrow endemics or habitat specialists based on taxonomic relatedness, similar distributions, and common threats to persistence. All assessments included a combined threats analysis, but few employed a common species' response model or expert elicitation process. Although ESA risk assessments are distinct from policy decisions, most assessments (50%) supported decisions that all species warranted endangered status. Available guidance has generally emphasized ecological similarity as the key attribute leading to successful multispecies assessments. The challenge with consistently selecting species based on qualitative proxies such as common distributions or threats to persistence is that ecological patterns and processes are scale dependent. Focusing instead on the assessment methods and their potential for bias and increased efficiency may provide a stronger basis for developing consistent and transparent guidance.

Imperiled species face numerous and diverse anthropogenic threats to their persistence, and wildlife managers charged with making conservation decisions benefit from a sound understanding of how populations, species, and ecosystems will respond to future changes in threats to biodiversity. In southeastern North America, the gopher tortoise (Gopherus polyphemus) is a keystone species in upland ecosystems; however, tortoise populations have declined strongly over the last century, and the species is a candidate for increased protection by the United States federal government under the Endangered Species Act (ESA). Here, we sought to support conservation decision making for G. polyphemus by developing a spatially-explicit predictive population model that linked four anthropogenic threats (climate warming, sea-level rise, urbanization, habitat degradation) to demographic vital rates and used the model to estimate future changes in the number of individuals, populations, and metapopulations across the species’ range. Using recent survey data, we projected 457 populations for 80 years into the future under scenarios varying in threat magnitude, management magnitude, and demographic uncertainty. Population projections predicted that the number of individuals, populations, and metapopulations would decline among all simulated scenarios in the next 80 years. Model predictions were more sensitive to variation in adult survival and immigration rates than to variation in threat magnitude. A scenario with decreased habitat management and threat effects from climate warming, sea-level rise, and urbanization predicted geographic variation in persistence probabilities for populations that might result in decreased genetic representation across the species' range. Our results can be used to support conservation listing decisions for the gopher tortoise as part of its federal Species Status Assessment and provide an analytical framework for how to link diverse threats to geographically-varying demographic rates during population viability analyses for wide-ranging imperiled species around the world.

Extensive urbanization in coastal southern California has reduced natural habitat in this biodiversity hotspot. To better conserve ecological communities, state and federal agencies, along with local jurisdictions and private stakeholders, developed regional conservation plans for southern California. Although many protected areas exist within this region, the patchwork nature of these protected areas might not provide good coverage for species that require multiple habitat components, such as amphibians with complex life histories. Because of declines in the past century, the status of the western spadefoot (Spea hammondii) in southern California is of concern to state and federal wildlife agencies. Species distribution models (SDMs) can aid in determining the conservation status of imperiled species by projecting where suitable habitat remains and how much is protected from further development. We built SDMs that integrated site-occupancy data from systematic pitfall trapping surveys and presence-only data from biodiversity databases and citizen science platforms to project the current distribution of western spadefoots in southern California. Western spadefoot occurrence was positively related to the cover of grassland or shrub/scrub and the % sand in the soil within a 1000 m buffer, and was negatively related to slope, elevation, and distance to ephemeral streams or vernal pools. Most of the remaining unprotected habitat for western spadefoots is in the southern half of its historical range in western San Diego and Riverside counties. A few large tracts of spadefoot habitat exist on U.S. Department of Defense lands and smaller tracts remain on ecological reserves owned by state and local government agencies. Only small patches of habitat remain in the northern half of this clade’s historical range in Ventura, Orange, Los Angeles, and San Bernardino counties. Existing regional conservation plans provide ostensible spatial coverage of the majority of extant habitat for western spadefoots in southern California, but most of the habitat within the jurisdiction of these plans lacks formal protection, exposing this species to further declines as urbanization continues in the 21st century.

Although karst vulnerability mapping was not used in the present assessment because it does not incorporate species response to threats, this approach may prove useful for extrapolating expert judgments on relative risk to unsampled karst regions. Using expert knowledge to support Endangered Species Act decision-making for data-deficient species I S. parvus i , I S. cooperi i , and I S. morrisoni i are restricted to portions of Virginia and West Virginia (Lewis 2001; Fong et al. 2007; Holsinger et al. 2013); I S. parvus i localities extend across 1,467 km SP 2 sp ; and I S. morrisoni i localities extend across 2,266 km SP 2 sp . Keywords: expert elicitation; extinction risk; remote elicitation; SHELF; species status assessment; Stygobromus; evaluación del estado de la especie; obtención de expertos; obtención remota; riesgo de extinción; ; ; ; ; ; Stygobromus EN expert elicitation extinction risk remote elicitation SHELF species status assessment Stygobromus evaluación del estado de la especie obtención de expertos obtención remota riesgo de extinción Stygobromus 1627 1638 12 10/05/21 20211001 NES 211001 Introduction Many questions relevant to conservation decision-making are characterized by extreme uncertainty due to lack of empirical data and complexity of the underlying ecological processes (Kuhnert et al. 2010). [Extracted from the article]

Abstract In 2015, the United States Fish and Wildlife Service initiated a review of the status of Canada lynx (Lynx canadensis) in the contiguous United States. Available research and monitoring, while substantial, lacked information on the demographic rates, abundance, and trends necessary to complete a full viability assessment. Therefore, alternative sources of information were needed to inform the species status assessment. We designed and conducted an expert elicitation to capture the knowledge, professional judgments, and opinions of lynx experts to assess the status of, and the drivers influencing, these lynx populations. We elicited the likelihood and level of uncertainty regarding future persistence over several time frames (at years 2025, 2050, and 2100). The elicitation revealed experts' concerns that expected climate‐driven losses in habitat quality, quantity, and related factors will likely result in declines. Experts expect resident populations of lynx will persist in all five currently occupied geographic units in 2025; in 4 or 5 of the units at 2050; and in 2 or 3 units at 2100. Experts expressed a high level of uncertainty regarding the rate and extent of decline due to projected climate warming and corresponding effects to these lynx populations. In the absence of adequate monitoring data, this type of expert elicitation is a useful method to aid classification decisions, such as providing the scientific information the Service relied upon to complete the November 5, 2017 5‐year review which recommended that the lynx distinct population segment be removed from the list of threatened and endangered species.

In 2015, the United States Fish and Wildlife Service initiated a review of the status of Canada lynx (Lynx canadensis) in the contiguous United States. Available research and monitoring, while substantial, lacked information on the demographic rates, abundance, and trends necessary to complete a full viability assessment. Therefore, alternative sources of information were needed to inform the species status assessment. We designed and conducted an expert elicitation to capture the knowledge, professional judgments, and opinions of lynx experts to assess the status of, and the drivers influencing, these lynx populations. We elicited the likelihood and level of uncertainty regarding future persistence over several time frames (at years 2025, 2050, and 2100). The elicitation revealed experts' concerns that expected climate‐driven losses in habitat quality, quantity, and related factors will likely result in declines. Experts expect resident populations of lynx will persist in all five currently occupied geographic units in 2025; in 4 or 5 of the units at 2050; and in 2 or 3 units at 2100. Experts expressed a high level of uncertainty regarding the rate and extent of decline due to projected climate warming and corresponding effects to these lynx populations. In the absence of adequate monitoring data, this type of expert elicitation is a useful method to aid classification decisions, such as providing the scientific information the Service relied upon to complete the November 5, 2017 5‐year review which recommended that the lynx distinct population segment be removed from the list of threatened and endangered species. Expert elicitation provided the means to assess lynx status in the contiguous United States in the absence of data supporting a demographic viability assessment. Our elicitation of lynx persistence probability revealed experts'; concerns that expected climate‐driven losses in habitat quality, quantity and related factors will likely result in declines. Experts expect resident populations of lynx will persist in all five currently occupied geographic units in 2025; in 4 or 5 of the units at 2050; and in 2 or 3 units at 2100 but expressed a high level of uncertainty regarding the rate and extent of decline. [ABSTRACT FROM AUTHOR]

Decisions about whether to designate a species for conservation and protection depend on the ability to summarize their population trajectories and their risk of extinction. Such decisions may rely on quantitative population viability analyses based on a time series of abundance index values that are derived from a monitoring program. In the case of the Longfin Smelt (Spirinchus thaleichthys), a decision to protect a distinct population segment of the species under the U.S. Endangered Species Act was informed by several indices of population abundance. In this paper, we combined individual population viability analyses into a single metric for extinction risk using a meta-analysis framework. Individual monitoring surveys for this species generally agreed that the trajectory of abundance was downward, but variation introduced uncertainty. Combining data from several surveys produced a better summary of the population growth rate. We also used the population growth rates in a simulation to estimate the probability that the abundance of Longfin Smelt dropped too low to recover. We found that this probability of quasi-extinction was substantial, exceeding 20 % over two decades. This study demonstrates a practical way that having multiple sources of information creates better information about the trajectory of a population. Individually, the surveys contribute information about specific life stages or ages to our understanding of the population. Combined into one metric and an associated graphical summary, this analysis succinctly communicates risk and creates a benchmark for evaluating future management decisions. [ABSTRACT FROM AUTHOR]

Under the United States Endangered Species Act, a species is granted protection if it is in danger of extinction throughout all or a significant portion of its range. Since 2016, the United States Fish and Wildlife Service has adopted a more analytical approach to determining significant portion of its range. Termed Species Status Assessment (SSA), this approach addresses whether loss of individuals from a portion of its range will influence at least one of the conservation biology principles of redundancy (ability to withstand catastrophic events), resiliency (ability to withstand stochastic events), and representation (ability to adapt over time to long-term changes in the environment). Using Sicklefin Redhorse (Moxostoma sp.), we illustrate the use of genetic data to evaluate each SSA metric. We sampled (n = 382) Sicklefin Redhorse from three major river basins throughout its contemporary distribution and estimated genetic parameters using ten microsatellite markers. Using STRUCTURE analyses, we showed that redundancy was three, but our approximate Bayesian computation analysis revealed that this value could be reduced to two if admixture, due to anthropogenic stressors of the 1900s, continues. We used estimates of effective population size (Ne) to measure resiliency and representation and found that all populations showed resiliency and representation with Ne ≥ 479. Genetic monitoring of the Little Tennessee and Tuckasegee populations will be necessary to assess the future status of redundancy for this species. Any reduction in redundancy would warrant further ESA evaluation. [ABSTRACT FROM AUTHOR]

Decisions under the U.S. Endangered Species Act (ESA) require scientific input on the risk that the species will become extinct. A series of critiques on the role of science in ESA decisions have called for improved consistency and transparency in species risk assessments and clear distinctions between science input and policy application. To address the critiques and document the emerging practice of the U.S. Fish and Wildlife Service (USFWS), we outline an assessment process based on principles and practices of risk and decision analyses that results in a scientific report on species status. The species status assessment (SSA) process has three successive stages: 1) document the life history and ecological relationships of the species in question to provide the foundation for the assessment, 2) describe and hypothesize causes for the current condition of the species, and 3) forecast the species' future condition. The future condition refers to the ability of a species to sustain populations in the wild under plausible future scenarios. The scenarios help explore the species' response to future environmental stressors and to assess the potential for conservation to intervene to improve its status. The SSA process incorporates modeling and scenario planning for prediction of extinction risk and applies the conservation biology principles of representation, resiliency, and redundancy to evaluate the current and future condition. The SSA results in a scientific report distinct from policy application, which contributes to streamlined, transparent, and consistent decision-making and allows for greater technical participation by experts outside of the USFWS, for example, by state natural resource agencies. We present two case studies based on assessments of the eastern massasauga rattlesnake Sistrurus catenatus and the Sonoran Desert tortoise Gopherus morafkai to illustrate the process. The SSA builds upon the past threat-focused assessment by including systematic and explicit analyses of a species' future response to stressors and conservation, and as a result, we believe it provides an improved scientific analysis for ESA decisions. [ABSTRACT FROM AUTHOR]

Essex County, Ontario, supports a diverse assemblage of Canadian herpetofauna. It is home to the only Canadian populations of three species/subspecies and contains two of Canada's 11 Important Amphibian and Reptile Areas. A checklist and status assessment of the herpetofauna of Essex County was previously compiled in 1983. Changes to natural habitats and an increase in monitoring efforts (e.g., citizen science) over the past 35 years warrant an updated assessment of herpetofaunal status. The county was subdivided using a 10 x 10 km grid overlay, and recent observations (1997-2016) submitted to provincial databases were tabulated for each grid square. We compared current status' of herpetofauna in Essex County to those of the 1983 study using a similar classification scheme of 'extirpated from Essex' (EE; no recent observations) and 'rare in Essex' (RE; distribution <5 squares). We found that 11 species declined in status. The majority of reptiles and amphibians (62%) that historically occurred in Essex County are now either EE (31%) or RE (31%) and almost half (45%) of the 29 extant species/subspecies are RE. A large proportion of salamanders and squamates are EE or RE (86% and 65%, respectively). Amount of natural area and sampling effort were important variables describing patterns of observed heipetofaunal species/subspecies richness, and observed richness was highest along the western and southern edges of the mainland (16-19 species). To prevent future extirpations, recovery efforts in Essex County should occur across multiple locations and target RE species. [ABSTRACT FROM AUTHOR]

Horseshoe crabs have persisted for more than 200 million years, and fossil forms date to 450 million years ago. The American horseshoe crab ( Limulus polyphemus), one of four extant horseshoe crab species, is found along the Atlantic coastline of North America ranging from Alabama to Maine, USA with another distinct population on the coasts of Campeche, Yucatán and Quintana Roo in the Yucatán Peninsula, México. Although the American horseshoe crab tolerates broad environmental conditions, exploitation and habitat loss threaten the species. We assessed the conservation status of the American horseshoe crab by comprehensively reviewing available scientific information on its range, life history, genetic structure, population trends and analyses, major threats, and conservation. We structured the status assessment by six genetically-informed regions and accounted for sub-regional differences in environmental conditions, threats, and management. The transnational regions are Gulf of Maine (USA), Mid-Atlantic (USA), Southeast (USA), Florida Atlantic (USA), Northeast Gulf of México (USA), and Yucatán Peninsula (México). Our conclusion is that the American horseshoe crab species is vulnerable to local extirpation and that the degree and extent of risk vary among and within the regions. The risk is elevated in the Gulf of Maine region due to limited and fragmented habitat. The populations of horseshoe crabs in the Mid-Atlantic region are stable in the Delaware Bay area, and regulatory controls are in place, but the risk is elevated in the New England area as evidenced by continuing declines understood to be caused by over-harvest. The populations of horseshoe crabs in the Southeast region are stable or increasing. The populations of horseshoe crabs in the Florida Atlantic region show mixed trends among areas, and continuing population reductions at the embayment level have poorly understood causes. Within the Northeast Gulf of Mexico, causes of population trends are poorly understood and currently there is no active management of horseshoe crabs. Horseshoe crabs within México have conservation protection based on limited and fragmented habitat and geographic isolation from other regions, but elevated risk applies to the horseshoe crabs in the Yucatán Peninsula region until sufficient data can confirm population stability. Future species status throughout its range will depend on the effectiveness of conservation to mitigate habitat loss and manage for sustainable harvest among and within regions. [ABSTRACT FROM AUTHOR]

Population projection models are important tools for conservation and management. They are often used for population status assessments, for threat analyses, and to predict the consequences of conservation actions. Although conservation decisions should be informed by science, critical decisions are often made with very little information to support decision-making. Conversely, postponing decisions until better information is available may reduce the benefit of a conservation decision. When empirical data are limited or lacking, expert elicitation can be used to supplement existing data and inform model parameter estimates. The use of rigorous techniques for expert elicitation that account for uncertainty can improve the quality of the expert elicited values and therefore the accuracy of the projection models. One recurring challenge for summarizing expert elicited values is how to aggregate them. Here, we illustrate a process for population status assessment using a combination of expert elicitation and data from the ecological literature. We discuss the importance of considering various aggregation techniques, and illustrate this process using matrix population models for the wood turtle (Glyptemys insculpta) to assist U.S. Fish and Wildlife Service decision-makers with their Species Status Assessment. We compare estimates of population growth using data from the ecological literature and four alternative aggregation techniques for the expert-elicited values. The estimate of population growth rate based on estimates from the literature (λ mean = 0.952, 95% CI: 0.87–1.01) could not be used to unequivocally reject the hypotheses of a rapidly declining population nor the hypothesis of a stable, or even slightly growing population, whereas our results for the expert-elicited estimates supported the hypothesis that the wood turtle population will decline over time. Our results showed that the aggregation techniques used had an impact on model estimates, suggesting that the choice of techniques should be carefully considered. We discuss the benefits and limitations associated with each method and their relevance to the population status assessment. We note a difference in the temporal scope or inference between the literature-based estimates that provided insights about historical changes, whereas the expert-based estimates were forward looking. Therefore, conducting an expert-elicitation in addition to using parameter estimates from the literature improved our understanding of our species of interest. • We estimated population growth rate of wood turtles using a stage-structured projection matrix. • The model was parameterized based on expert elicitation. • The aggregation method used affected model estimates. • There was evidence of a (possibly rapid) population decline. [ABSTRACT FROM AUTHOR]

We assessed the extinction risks of Malagasy amphibians by evaluating their distribution, occurrence in protected areas, population trends, habitat quality, and prevalence in commercial trade. We estimated and mapped the distribution of each of the 220 described Malagasy species and applied, for the first time, the IUCN Red List categories and criteria to all species described at the time of the assessment. Nine species were categorized as critically endangered, 21 as endangered, and 25 as vulnerable. The most threatened species occur on the High Plateau and/or have been subjected to overcollection for the pet trade, but restricted extent of occurrence and ongoing habitat destruction were identified as the most important factors influencing extinction threats. The two areas with the majority of threatened species were the northern Tsaratanana-Marojejy-Masoala highlands and the southeastern Anosy Mountains. The current system of protected areas includes 82% of the threatened amphibian species. Of the critically endangered species, 6 did not occur in any protected area. For conservation of these species we recommend the creation of a reserve for the species of the group, the inclusion of two species in the Convention on the International Trade in Endangered Species Appendix II, and the suspension of commercial collecting for . Field surveys during the last 15 years reveal no pervasive extinction of Malagasy amphibians resulting from disease or other agents, as has been reported in some other areas of the world. [ABSTRACT FROM AUTHOR]

Population persistence probability is valuable for characterizing risk to species and informing listing and conservation decisions but is challenging to estimate through traditional methods for rare, data-limited species. Modeling approaches have used citizen science data to mitigate data limitations of focal species and better estimate parameters such as occupancy and detection, but their use to estimate persistence and inform conservation decisions is limited. We developed an approach to estimate persistence using only occurrence records of the target species and citizen science occurrence data of non-target species to account for search effort and imperfect detection. We applied the approach to a highly cryptic and data-limited species, the southern hognose snake (Heterodon simus), as part of its USFWS Species Status Assessment, and estimated current (in 2018) and future persistence under plausible scenarios of varying levels of urbanization, sea level rise, and management. Of 222 known populations, 133 (60%) are likely extirpated currently (persistence probability < 50%), and 165 (74%) populations are likely to be extirpated by 2080 with no additional management. Future management scenarios that included strategies to acquire and improve habitat on currently unprotected lands with existing populations lessened the estimated rate of population declines. These results can directly inform listing decisions and conservation planning for the southern hognose snake by Federal, State, and other partners. Our approach – using occurrence records and auxiliary data from non-target species to estimate population persistence – is applicable across rare and at-risk species for evaluating extinction risk with limited data and prioritizing management actions. Unlabelled Image • At-risk species are often data-limited but in need of conservation decisions. • Population persistence was estimated from target species occurrence records. • Citizen science data of non-target species accounted for imperfect detection. • A majority (60%) of target species populations are likely extirpated at present. • Acquiring and improving lands with extant populations lessened population declines. [ABSTRACT FROM AUTHOR]