Range Assessment for Georgia Blind Salamander, Dougherty Plain Cave
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RANGE ASSESSMENT IN GEORGIA FOR TWO THREATENED GROUNDWATER SPECIES OF THE FLORIDAN AQUIFER (CAMBARUS CRYPTODYTES AND EURYCEA WALLACEI) FINAL REPORT SUBMITTED TO: GEORGIA DEPARTMENT OF NATURAL RESOURCES WILDLIFE RESOURCES DIVISION 2070 US HWY 278 SE SOCIAL CIRCLE, GA 30025-4711 17 DECEMBER 2015 DANTE B. FENOLIO, PH.D.1 MATTHEW L. NIEMILLER, PH.D.2 ANNA M. MCKEE, PH.D.3 1 Vice President, Conservation and Research, San Antonio Zoo, 3903 N St Mary's St., San Antonio, TX 78212; Phone: (210)247-9294); E-mail: [email protected] 2 Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, IL 61820. Phone: (615) 427-3049; E-mail: [email protected] or [email protected] 3 U.S. Geological Survey, South Atlantic Water Science Center, Norcross, GA 30093. Phone: (678) 924- 6671; E-mail: [email protected] 1 INTRODUCTION On 20 April 2010, the Center for Biological Diversity (CBD) petitioned the United States Fish and Wildlife Service to list 404 aquatic, riparian, and wetland species from the Southeastern United States as threatened or endangered under the Endangered Species Act (CBD 2010). This petition states, “Pursuant to Section 4(b) of the Endangered Species Act (“ESA”), 16 U.S.C. §1533(b), Section 553(3) of the Administrative Procedures Act, 5 U.S.C. § 553(e), and 50 C.F.R. §424.14(a), the Center for Biological Diversity, Alabama Rivers Alliance, Clinch Coalition, Dogwood Alliance, Gulf Restoration Network, Tennessee Forests Council, West Virginia Highlands Conservancy, Tierra Curry and Noah Greenwald hereby formally petition the Secretaries of Interior and Commerce to list 404 aquatic, riparian and wetland species from the southeastern U.S. as Threatened or Endangered species and to designate critical habitat concurrent with listing.” The list of 404 proposed species includes the Georgia Blind Salamander, Eurycea wallacei, and the Dougherty Plain Cave Crayfish, Cambarus cryptodytes (Fig. 1). Both species are found in the same habitats within the Floridan Aquifer. Clarification of the distribution, number of populations, and population status of each species is important with regard to their conservation (CBD 2010; Fenolio et al. 2013).Importantly, there are large areas between known localities wherein there are no documented occurrences of either species (Fenolio et al. 2013). The CBD petition states the following regarding the known distribution of E. wallacei: “The Georgia Blind Salamander occurs in Jackson County, Florida, and in Dougherty and Decatur counties, Georgia, in the Marianna Lowlands-Dougherty Plain physiographic region which is a vast karst area of passageways and exposed vadose caves (NatureServe 2008, AmphibiaWeb 2009). The species is known from a deep well in Albany, Georgia, and from Climax Cave. In the Florida Panhandle the species has been detected at approximately a dozen sites which allow access to the Floridan Aquifer, which circulates in underground passageways in limestones of the Ocala and Suwannee formations (AmphibiaWeb 2009).” The CBD petition states the following regarding the known distribution of C. cryptodytes: “NatureServe (2008) reports that the Dougherty Plain cave crayfish occurs in the aquifer of the Dougherty Plain (Marianna Lowlands), from Decatur County, Georgia, to Jackson County, Florida, USA. All known sites can be enclosed by 50 km circle, and all lie within the Apalachicola River basin. Skelton (2008) states that "The species is currently known from Dougherty and Decatur counties in southwestern Georgia and Jackson and Washington counties, in the Panhandle of Florida. It almost certainly occurs in Mitchell and Baker counties, Georgia, as these counties lie between Dougherty and Decatur Counties, in southwest Georgia."” Population level data are largely unknown for either species. The CBD petition states the following regarding known populations of E. wallacei: “NatureServe (2008) states that there are between 6 and 20 populations with less than 1000 individuals in total. There are approximately 15-20 EOs, but these all are relatively close and may even be interconnected.” 2 The CBD petition states the following regarding populations of C. cryptodytes: “NatureServe (2008) states that there are between 6 and 20 populations with less than 1000 individuals in total. There are approximately 15-20 EOs, but these all are relatively close and may even be interconnected.” The status of Eurycea wallacei was recently summarized by Fenolio et al. (2013) and pertinent information for both species was included in the CBD petition as follows: For E. wallacei: “The Georgia Blind Salamander is critically imperiled in Georgia (S1) and imperiled in Florida (S2). It is categorized as vulnerable by the IUCN.” For C. cryptodytes: “According to NatureServe (2008), Cambarus cryptodytes is narrowly endemic. While there are a moderate number of occurrences, they all lie within a small, county-sized area. In Florida this species has a status of imperiled, and in Georgia it is critically imperiled (NatureServe 2008). The State of Georgia lists the Dougherty Plains cave crayfish as Threatened (Skelton 2008). Florida lists it as a Species of Greatest Conservation Need. It is ranked as vulnerable by the IUCN and as threatened by the American Fisheries Society.” The Floridan Aquifer is a principal artesian aquifer that underlies over 250,000 km2 in southern Alabama, southern Georgia, southern South Carolina, and all of Florida. It is the source of water for several large Southeastern U.S. cities, such as Savannah, Georgia, and Jacksonville, Tallahassee, and Orlando, Florida. Land above the aquifer has been altered from its natural state, largely for agricultural purposes. For this reason, the Floridan Aquifer has been identified as an at risk aquifer for nitrate contamination (from fertilizers) by the United States Geological Survey (Nolan et al. 1998). From a wildlife management perspective, groundwater contamination is a serious problem. Because so many groundwater species are found in single aquifer systems, a single contamination event could pose an extinction threat. For example, in 1981, liquid ammonia nitrate and urea fertilizer were spilled in the Ozark Highlands of Missouri, contaminating an underlying aquifer. Living and dead groundwater fauna ranging from stygobiotic cavefish to crayfish to cave salamander larvae washed out of a spring fed by the aquifer roughly 21 km from the spill site (Crunkilton 1984). Such an event could extirpate local populations of threatened and imperiled groundwater fauna in the Floridan Aquifer. 3 Figure 1. A Georgia Blind Salamander (Eurycea wallacei) and Dougherty Plain Cave Crayfish (Cambarus cryptodytes) from Hole in the Wall Cave, Merritt’s Mill Pond, Jackson Co., Florida. Photographs by Dante B. Fenolio. The Georgia Blind Salamander was described by Carr (1939) as Haideotriton wallacei based on a specimen taken from a 200 foot well near Albany, Georgia. However, Frost et al. (2006) recently synonymized the genus Haideotriton into Eurycea based on molecular analyses. This neotenic species inhabits the Floridan Aquifer in the Marianna Lowlands and the Dougherty Plain, where artesian waters are contained in carbonate strata of the Ocala and Suwannee formations (Means 2005). Georgia Blind Salamanders have been reported from just seven localities in Georgia (two of which have been destroyed) and 29 localities in northwestern Florida (Pylka and Warren 1958; Dundee 1962; Means 1977, 1992, 2005; Morris 2006), including 22 in Jackson County, five in Washington County, and one in Calhoun County (Fig. 2). These records include vadose caves, sinkholes, wells, and partially or completely submerged limestone cave systems (Pylka and Warren 1958; Dundee 1962; Means 1977, 1992, 2005). Georgia Blind Salamanders are at risk from several anthropogenic threats, the most serious of which are over-harvesting of groundwater and groundwater pollution (Means, 1977, 1992, 2005; USGS 2005). Consequently, the species is listed as “Vulnerable” by IUCN (Hammerson 2004) and “Imperiled” (G2) by NatureServe (Natureserve 2015) because of few known occurrences, limited geographic distribution, potential rangewide threats and declines in range and population size. The Georgia Blind Salamander is also listed as a species of conservation concern in both Florida and Georgia. The Dougherty Plain Cave Crayfish was described by Hobbs (1941). The species also occurs in the Marianna Lowlands and Dougherty Plain sections of the Floridan Aquifer, primarily from Decatur Co., Georgia, to Washington Co., Florida, within the Apalachicola, and Choctawhatchee River and Econfina 4 Creek basins (Hobbs 1981, 1989; Morris 2006; P. Moler, pers. comm.). Dougherty Plain Cave Crayfish have been reported from just eight localities in Georgia in Baker, Calhoun, Decatur, and Dougherty counties, and 29 localities in northwestern Florida, including 23 in Jackson County, five in Washington County, and one in Calhoun County (Hobbs et al. 1977; Hobbs 1981; Franz et al. 1994; Purvis and Opsahl 2005; Morris 2006; Skelton 2008). The majority of records are from submerged freshwater limestone caves but the species also has been observed from wells, sinks, and vadose caves. Little is known regarding the life history and ecology of this species. The species is listed as “Least Concern” by IUCN (Cordeiro et al. 2010) due to its broad distribution and large number of occurrences. However, it is considered “Imperiled” (G2) by NatureServe (NatureServe 2015). The Dougherty Plain Cave Crayfish is designated