Purple Bean Villosa perpurpurea (= Tennessee Bean; Venustaconcha trabalis) 5-Year Review: Summary and Evaluation U.S. Fish and Wildlife Service Southwestern Virginia Field Office Abingdon, Virginia August 2020 1 5-YEAR REVIEW Purple Bean; Villosa perpurpurea (Tennessee Bean; Venustaconcha trabalis) 1.0 GENERAL INFORMATION 1.1 Reviewers Lead Regional or Headquarters Office: North Atlantic-Appalachian Region, Hadley, MA; Martin Miller, 413-253-8615; [email protected] Lead Field Office: Jordan Richard, Southwestern Virginia Field Office, 757-570-3697; [email protected] Cooperating Field Office(s): Jennifer Garland, Kentucky ES Field Office, 502-695-0468 (x46115); [email protected] Anthony Ford, Tennessee ES Field Office, 931-525-4982, [email protected] Jeff Powell, Alabama ES Field Office, 251-441-5858, [email protected] Cooperating Regional Office(s): South Atlantic-Gulf Region, Atlanta, GA; Carrie Straight, 404-679-7226; [email protected] 1.2 Methodology used to complete the review: Public notice of this review was provided in the Federal Register on August 8, 2018 and a 30-day comment period was opened (83 FR 39113). We obtained information on the status of this species from several experts on the taxa, and additional data were obtained from the recovery plan, peer-reviewed scientific literature, and our state and private partners. Once all known literature and information was compiled, Jordan Richard, Fish and Wildlife Biologist with the Southwestern Virginia Field Office, completed the review. All literature and documents used for this 5-year review are on file at the Southwestern Virginia Field Office and are cited below in the References section. Biologists in the Kentucky Field Office, Tennessee Field Office, and Alabama Field Office provided an initial review of the 5-year review, and their comments were incorporated into the five-year review, as appropriate. 1.3 Background: Current nomenclature and geographic understanding for the Tennessee Bean (Venustaconcha trabalis) and Cumberland Bean (Venustaconcha troostensis) When listed in 1997 (62 FR 1648) and last reviewed in 2013, the purple bean (Villosa perpurpurea) was limited to the Tennessee River system and recognized as a mussel with a purple nacre (See Appendix A). At that time its close relative, the Cumberland bean 2 (Villosa trabalis), was reported to occur in both the Tennessee and Cumberland River systems as a white-nacred mussel. Recently, taxonomy for the Cumberland bean and purple bean has changed based on genetic and phylogenetic taxonomic assessments by Kuenhl (2009) and Lane et al. (2016, 2019). These studies provided evidence supporting recognition of the Cumberland River populations of the Cumberland bean as Venustaconcha troostensis, while the Tennessee River populations of both Villosa trabalis and Villosa perpurpurea were combined and recognized as a single species, now Venustaconcha trabalis (Tennessee bean). Williams et al. (2017) provided a revised list of 298 mussel species of the United States and Canada, including the Tennessee bean, which incorporated changes in nomenclature and systematic taxonomy since the most recent checklist in 1998. This document is accepted by most mussel experts as the most current and accepted taxonomic structure of North American unionids. Because the Service has not yet addressed these taxonomic changes relative to each species listing status (see section 4 for future recommended actions based on this new information), it is appropriate to conduct concurrent five-year reviews for the Cumberland bean and purple bean (= Tennessee bean) in an effort to reduce potential confusion caused by these nomenclatural changes. This 5-year review addresses the current understanding of the status of the Tennessee bean (Villosa perpurpurea = Venustaconcha trabalis), as it occurs in the Tennessee River basin in Virginia and Tennessee. This review also includes purple bean (= Tennessee bean) populations in the Hiwassee River and the populations reintroduced, using Hiwassee River broodstock, in the Nolichucky and Paint Rock Rivers, as they were historically considered to be Cumberland bean. A concurrent review of the Cumberland bean is being conducted by the Service’s Kentucky Field Office and will include the same information regarding the Hiwassee River population. When the Service evaluates the taxonomic changes and makes a determination of the listing status of each taxon in the future, the 5-year reviews for the Cumberland bean and purple bean (= Tennessee bean) will serve as a baseline assessment and contain the most current status information on the taxa. The purple bean (= Tennessee bean) has never been thought to exist – historically or currently – within the Cumberland River drainage. The recent taxonomic changes affecting the Tennessee bean and Cumberland bean specifically affect the population from the Hiwassee River and the populations reintroduced, using Hiwassee River broodstock, in the Nolichucky and Paint Rock Rivers. Within the Tennessee River drainage, all other extant localities (Clinch River, Indian Creek, Copper Creek, Beech Creek, Obed River, Emory River, and Clear Creek) have always been – and continue to be – considered purple bean (= Tennessee bean). 1.3.1 FR Notice citation announcing initiation of this review: 83 FR 39113; August 8, 2018. 3 1.3.2 Listing history Original Listing FR notice: 62 FR 1647-1658 Date listed: January 10, 1997 Entity listed: Species Classification: Endangered 1.3.3 Associated rulemakings: Designation of Critical Habitat Title: Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Five Endangered Mussels in the Tennessee and Cumberland River Basins; Final Rule FR notice: 69 FR 53136-53180 Effective date: September 30, 2004 1.3.4 Review History: Previous 5-Year Reviews Initiated: 71 FR 20717-20718; April 21, 2006 Date Finalized: October 24, 2006 Results: No change in status Initiated: 76 FR 33334-33336; June 8, 2011 Date Finalized: October 2013 Results: No change in status 1.3.5 Species’ Recovery Priority Number at start of 5-year review: 5. This designation corresponds to a species with a high degree of threat and low recovery potential. 1.3.6 Recovery Plan or Outline Name of plan or outline: Recovery Plan for Cumberland Elktoe (Alasmidonta atropurpurea), Oyster Mussel (Epioblasma capsaeformis), Cumberland Combshell (Epioblasma brevidens), Purple Bean (Villosa perpurpurea), and Rough Rabbitsfoot (Quadrula cylindrica strigillata) (69 FR 29569-29570). Date issued: May 4, 2004 2.0 REVIEW ANALYSIS 2.1 Application of the 1996 Distinct Population Segment (DPS) policy 2.1.1 Is the species under review a vertebrate? The purple bean (= Tennessee bean) is an invertebrate; therefore, it is not covered by the DPS policy. 2.2 Recovery Criteria 4 2.2.1 Does the species have a final, approved recovery plan containing objective, measurable criteria? Yes, the species has an approved plan containing recovery criteria. 2.2.2 Adequacy of recovery criteria. 2.2.2.1 Do the recovery criteria reflect the best available and most up-to date information on the biology of the species and its habitat? No. The recovery plan should be updated to reflect the new understanding of the species range, per recommended actions in section 4.0. 2.2.3 List the recovery criteria as they appear in the recovery plan, and discuss how each criterion has or has not been met, citing information: Small population size, destruction of habitat, and poor water quality are the predominant factors inhibiting recovery of the purple bean (= Tennessee bean). Therefore, the following downlisting and delisting criteria primarily address listing Factor A (Present or threatened destruction, modification or curtailment of its habitat or range). Note that the recovery criteria listed below are excerpted from the Recovery Plan and therefore refer to the purple bean, which remains the name of the ESA-listed entity. We will refer to the species as Tennessee bean throughout the remainder of the document, and discuss recovery criteria in the context of the Tennessee bean’s geographic range, as discussed in Sections 2.3.1.3 through 2.3.1.5. Until the taxonomic and range changes described in those sections have been completed, the recovery criteria will not reflect the most up-to- date information on the biology of the Tennessee bean and its habitat. Downlisting from endangered to threatened status will occur when the following criteria are met for the protection of extant stream populations, discovery of currently unknown stream populations, and/or reestablishment of historical stream populations [Delisting criteria, where different from downlisting criteria, are italicized and in brackets]: (1) At least four [five] distinct viable stream populations of the purple bean in the Upper Tennessee River system. This will be accomplished by: (1) Protecting all extant stream populations (i.e., upper Clinch River/Indian Creek, lower Clinch River/Copper Creek, Obed River, Beech Creek) and ensuring that they all have viable population status. [(2) Reestablishing a viable stream population in the upper Tennessee River system (e.g., Powell River).] The Recovery Plan defines a viable population as “a wild, naturally reproducing population that is large enough to maintain sufficient genetic variation to enable the species to evolve and respond to natural habitat changes without further intervention.” This criterion has not been met. Appendix B provides an overview of populations, watersheds, and current