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Species Status Assessment Report for Beaverpond Marstonia

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Species Status Assessment Report for Beaverpond Marstonia Species Status Assessment Report For Beaverpond Marstonia (Marstonia castor) Marstonia castor. Photo by Fred Thompson Version 1.0 September 2017 U.S. Fish and Wildlife Service Region 4 Atlanta, Georgia 1 2 This document was prepared by Tamara Johnson (U.S. Fish and Wildlife Service – Georgia Ecological Services Field Office) with assistance from Andreas Moshogianis, Marshall Williams and Erin Rivenbark with the U.S. Fish and Wildlife Service – Southeast Regional Office, and Don Imm (U.S. Fish and Wildlife Service – Georgia Ecological Services Field Office). Maps and GIS expertise were provided by Jose Barrios with U.S. Fish and Wildlife Service – Southeast Regional Office. We appreciate Gerald Dinkins (Dinkins Biological Consulting), Paul Johnson (Alabama Department of Conservation and Natural Resources), and Jason Wisniewski (Georgia Department of Natural Resources) for providing peer review of a prior draft of this report. 3 Suggested reference: U.S. Fish and Wildlife Service. 2017. Species status assessment report for beaverpond marstonia. Version 1.0. September, 2017. Atlanta, GA. 24 pp. 4 Species Status Assessment Report for Beaverpond Marstonia (Marstonia castor) Prepared by the Georgia Ecological Services Field Office U.S. Fish and Wildlife Service EXECUTIVE SUMMARY This species status assessment is a comprehensive biological status review by the U.S. Fish and Wildlife Service (Service) for beaverpond marstonia (Marstonia castor), and provides a thorough account of the species’ overall viability and extinction risk. Beaverpond marstonia is a small spring snail found in tributaries located east of Lake Blackshear in Crisp, Worth, and Dougherty Counties, Georgia. It was last documented in 2000. Based on the results of repeated surveys by qualified species experts, there appears to be no extant populations of beaverpond marstonia. Failure to detect the species in surveys to date in beaverpond marstonia’s type locality and similar habitat in surrounding areas indicates that the species is likely extinct. We used the best available information to describe the species’ viability. We have assessed the overall species status including the species’ needs, current condition, and future condition with respect to three factors of viability (Table ES-1). The three factors of viability – resiliency, redundancy, and representation – are currently absent, which leads us to conclude that the beaverpond marstonia has no viability and appears to be extinct. Table ES-1. Overall species status assessment summary for beaverpond marstonia. 5 3Rs Needs Current Condition Future Condition (Viability) Resiliency Functioning spring No known No resiliency (Large ecosystems current populations able Adequate flow for populations to withstand stochastic streams Historical events) Known populations locations Habitat with dewatered submerged vegetation Redundancy Multiple No known No (Number and populations populations redundancy distribution of throughout the populations to range of the species withstand catastrophic events) Representation Genetic variation No known No known (genetic and exists between populations representation. ecological populations diversity to maintain Ability to survive adaptive under different potential) habitat conditions 6 Table of Contents EXECUTIVE SUMMARY........................................................................................................... 4 CHAPTER 1. INTRODUCTION................................................................................................ 7 CHAPTER 2. BIOLOGY AND LIFE HISTORY....................................................................... 9 2.1 Taxonomy................................................................................................................................. 9 2.2 Morphological Description..................................................................................................... 10 2.3 Life History............................................................................................................................. 10 2.4 Reproduction........................................................................................................................... 10 2.5 Ecology................................................................................................................................... 11 2.6 Habitat.................................................................................................................................... 11 CHAPTER 3. CURRENT CONDITION.................................................................................... 13 3.1 Range and Distribution........................................................................................................... 13 3.2 Current Condition of Historical Locations............................................................................. 15 3.3 Current Condition of Populations.......................................................................................... 15 3.4 Current Beaverpond Marstonia Habitat Conditions............................................................... 13 3.5 Summary of Current Conditions............................................................................................. 14 CHAPTER 4. FACTORS INFLUENCING VIABILITY.......................................................... 15 4.1 Introduction............................................................................................................................ 16 4.2 Natural Stochastic Events....................................................................................................... 16 4.3 Drought ...…………............................................................................................................... 16 CHAPTER 5. SPECIES VIABILITY......................................................................................... 17 5.1 Introduction........................................................................................................................... 17 5.2 Resiliency............................................................................................................................... 17 5.3 Redundancy........................................................................................................................... 17 5.4 Representation....................................................................................................................... 17 5.5 Status Assessment Summary................................................................................................. 17 LITERATURE CITED............................................................................................................... 19 7 CHAPTER 1. INTRODUCTION Beaverpond marstonia (Marstonia castor) was historically found only in Georgia, at its type locality, Cedar Creek (over Coney Road) in Crisp County, and in two additional locations; 1) in Swift Creek, Worth County and 2) Mercer Mill Creek, Dougherty County. The beaverpond marstonia had previously been considered for listing under the Endangered Species Act of 1973, as amended (Act), and has been assigned status as a category 2 candidate species. A category 2 candidate species was one for which there was some evidence of vulnerability, but for which additional biological information was needed to support a proposed rule to list as endangered or threatened. This system of categories was discontinued in 1996 (December 5, 1996; 61 FR 64481) in favor of maintaining a list that only represented those species for which we have on file sufficient information on biological vulnerability and threats to support a proposal to list as endangered or threatened, but for which preparation and publication of a proposal is precluded by higher priority listing actions. On April 20, 2010, Center for Biological Diversity (CBD) and others petitioned the Service to list the beaverpond marstonia as endangered or threatened under the Act as part of the mega- petition to list 404 species in the southeastern United States. The petition identified habitat destruction, inadequacy of existing regulatory mechanisms, water pollution, and stochastic genetic and environmental events as threats to the species. On September 27, 2011, the Service published a substantial 90-day finding for 374 species, including the beaverpond marstonia. On December 30, 2015, the Service received a notice of intent to sue from CBD to compel the Service to issue a 12-month finding as to whether the listing of the beaverpond marstonia under the Act is warranted, not warranted, or warranted but precluded. On August 30, 2016, the Service entered into a stipulated settlement agreement with specifying that they would submit the 12- month finding to the Federal Register by April 1, 2017. This document constitutes the Service’s 12-month finding on the April 20, 2010 petition to list the beaverpond marstonia as endangered under the Act. This Species Status Assessment (SSA) Report was completed using the best available scientific information on the beaverpond marstonia to evaluate the species’ needs, current condition, and anticipated future condition. Based on the results of repeated surveys by qualified species experts, there appear to be no extant populations of beaverpond marstonia. It does not appear that the beaverpond marstonia is actually still extant, but rather is extinct; however, extinction of a species is difficult to prove, and there is inherent uncertainty in drawing an absolute conclusion of extinction. This SSA reviews
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