New occurrence records for Eurycea tonkawae Chippindale, Price, Wiens & Hillis, 2000 (Caudata, Plethodontidae) from an urbanized watershed in Travis County, Texas, USA

Abstract

We report two new occurrence records for Jollyville Plateau Salamanders, Eurycea tonkawae Chippindale, Price, Wiens & Hillis, 2000, from an urbanized watershed in Travis County, Texas, USA. Eurycea tonkawae is listed as federally threatened under the Endangered Species Act of 1973 due to threats from urbanization, including degradation of water quality and quantity. These new records fill a distributional gap within its known range, highlight the importance of surveying historically neglected areas, identify unprotected populations, and encourage the discovery of new populations.

Development and validation of an environmental DNA assay to detect federally threatened groundwater salamanders in central Texas

“…The United States Fish and Wildlife Service (USFWS) protects seven species [ 15 – 19 ], Texas Parks and Wildlife Department (TPWD) protects four additional species [ 20 ], and more listing petitions are predicted [ 1 ]. Consequently, surveys are commonly conducted for these taxa to determine occupancy of a target locality [ 13 ], population size [ 8 , 21 ], or species distribution [ 22 ]. Surface habitat and accessible cave streams can be surveyed by searching under and in submerged cover objects and with various trapping techniques [ 2 , 23 – 25 ], but some of these locations require considerable effort to detect salamanders [ 13 , 22 ].…”

“…Some are stygobiontic (obligate aquifer-dwellers), such as E. rathbuni and E. waterlooensis [3,4], while others, at minimum, migrate to subsurface habitat for oviposition [5][6][7][8][9] or as a temporary refuge from drying surface conditions [2,10,11]. Epigean (surface) populations typically occur proximate to a spring outlet or a portion of the creek gaining subterranean water [2, 9, but also see 12,13].…”

“…Consequently, surveys are commonly conducted for these taxa to determine occupancy of a target locality [13], population size [8,21], or species distribution [22]. Surface habitat and accessible cave streams can be surveyed by searching under and in submerged cover objects and with various trapping techniques [2,[23][24][25], but some of these locations require considerable effort to detect salamanders [13,22]. Biological surveys in subterranean water are challenging [26][27][28], and subterranean salamander surveys are typically conducted by trapping spring outlets and wells when human access is not possible [22,24,29].…”

Predicting surface abundance of federally threatened Jollyville Plateau Salamanders (Eurycea tonkawae) to inform management activities at a highly modified urban spring

“…Eurycea tonkawae are neotenic, permanently aquatic, plethodontid salamanders restricted to groundwater-fed aquatic habitats, such as springs, spring-fed creeks, and caves, primarily in the northern segment of the Edwards Aquifer ( Chippindale et al, 2000 ; Chippindale, 2005 ). Individuals are usually observed proximate to a spring outlet or a stream segment gaining groundwater ( Sweet, 1982 ; Bowles, Sanders & Hansen, 2006 ), but can also be observed downstream of springs and in second order creeks ( Bendik, McEntire & Sissel, 2016 ; Adcock et al, 2020 ). Typical surface habitat consists of shallow, flowing water with ample cover objects ( e.g ., rocks, leaf litter), substrate that provides interstitial spaces and access to subterranean water, and water chemistry associated with karst aquifers ( Chippindale, 2005 ; Bowles, Sanders & Hansen, 2006 ; U.S.…”