Jollyville Plateau Salamander, Tonkawa Springs Salamander
© 2013 Nathan Bendik (1 of 2)
Distribution and Habitat
Country distribution from AmphibiaWeb's database: United States
U.S. state distribution from AmphibiaWeb's database: Texas
Life History, Abundance, Activity, and Special Behaviors
Numbers of E. tonkawae are highest during spring and summer months (March to August), particularly juvenile salamanders. Average salamander densities are greater within undeveloped watersheds than in developed areas (Bowles et al 2006).
Eurycea tonkawae primarily preys upon benthic macroinvertebrates such as chironomid larvae and amphipods (City of Austin 2001).
Trends and Threats
Bowles et al. (2006) carried out salamander surveys at nine stream sites on Jollyville Plateau from December 1996 to December 1998 to assess the impacts of urbanization along these habitats. These nine sites were classified as either developed or undeveloped, depending upon the percentage of impervious cover (Bowles et al. 2006). Mean salamander densities were significantly lower within developed tributaries in relative to undeveloped tributaries. One reason for this difference may be higher water conductance. Another reason might be an increase in ion levels in surface water from Bull Creek and Barton Creek, which has been attributed to roadway runoff, fertilizer applications and wastewater line leaks (Johns 1994; Johns & Pope 1998). The City of Austin (2001) also reported that salamander densities were lower in areas with higher ionic constituents, including chloride, potassium, sodium, and sulfate. Amphibian eggs and larvae are highly sensitive to chemical runoff and pollutants, including pesticides, organophosphates, and petroleum hydrocarbons (USFWS 2002). The prey of E. tonkawae (amphipods and other crustaceans) are also highly susceptible to water pollution. Thus pollutant effects ranging from change of water chemistry to contaminated prey could potentially lead to developmental abnormalities, low reproduction, and overall reduction of survival for this salamander (USFWS 2002).
The lack of a constant, clean water supply is another pressing issue. Eurycea tonkawae’s main water supply originates from the Edwards and Trinity Aquifers, which are located in areas highly susceptible to urbanization. Some of the aquifers near Jollyville Plateau are the sole sources of drinking water for nearby communities, further increasing the risk of a reduction in water flow to areas inhabited by Eurycea tonkawae (Herbez 2005).
According to the Petition for E. tonkawae as an Endangered Species (2005), about 50% of northern watersheds were developed, with an additional 5% receiving approval for development. Currently, the Bull Creek watershed supports the largest populations of E. tonkawae, and has undergone major changes in development and urbanization in recent years. One tributary, Barrows Spring, has impervious cover of nearly 27%. However, several sewage spills occurred from 1993-1996, which may have resulted in high nitrate concentrations in Barrows Spring (Herbez 2005). Another tributary in Bull Creek, the Hanks tract, originally produced 70-80 salamanders during counts in 1997-1998. Currently, it is rare for more than one individual E. tonkawae salamander to be found there at any given time (City of Austin 2001). Heavy development and urbanizations around tracts and tributaries of Bull Creek suggest an uncertain future for Jollyville Plateau Salamanders in years ahead.
E. tonkawae is sensitive to rapid development and urbanization that produces pollution as well as altering ion concentrations and reducing fresh water supply. Being restricted to a limited range makes the overall population highly susceptible to degradation of water quality. The future of E. tonkawae depends on constant water supply of adequate quality and in controlling the rate of urbanization around the major tracts and tributaries in which this species lives.
Possible reasons for amphibian decline
General habitat alteration and loss
Bowles, B. D., Hansen, R.S., and Sanders, M. S. (1998). ''Ecology of the Jollyville Plateau Salamander (Eurycea tonkawae: Plethodontidae) with an assessment of the potential effects of urbanization.'' Hydrobiologia, 553, 111-120.
Chippindale, P. T., Price, A. H., Hillis, D. M., and Wiens, J. J. (2001). ''Phylogenetic relationships and systematic revision of Central Texas hemidactyline plethodontid aalamanders.'' Herpetological Monographs, 14, 1-80.
City of Austin (2001). ''Jollyville Plateau Water Quality and Salamander Assessment.'' Water Quality Report Series COA-ERM- 1999-2001: 1-141.
Duellman, W. E. (1978). ''The biology of an equatorial herpetofauna in Amazonian Ecuador.'' Miscellaneous Publications of the University of Kansas Museum of Natural History, 65, 1-352.
Herbez, E. (2005). ''Petition to the U.S. Fish and Wildlife Service for Listing of the Salamander Eurycea tonkawae as an Endangered Species.''
Johns, D.A. and Woodruff, Jr., C.M. (1994). ''Groundwater quality in the Bull Creek Basin.'' Edwards Aquifer -- Water Quality and Land Development in the Austin, Texas Area. D.A. Johns and C.M. Woodruff, Jr., eds., Austin Geological Society, Austin, Texas, USA, 18-36.
Naked City: The Jollyville Salamander (March 9, 2007). Austin Chronicle News. Retrieved July 18, 2007 from http://www.austinchronicle.com/gyrobase/Issue/story?oid=oid:453487.
Tupa, D.D. and Davis, W.K. (1976). ''Population dynamics of the San Marcos salamander, Eurycea nana Bishop.'' Texas Journal of Science, 27, 179-195.
U.S. Fish and Wildlife Service (2002). ''Candidate listing and priority assessment forms for the Jollyville Plateau Salamander.'' Petition to the U.S. Fish and Wildlife Service for Listing of the Salamander Eurycea tonkawae as an Endangered Species. E. Herbez, eds., Austin, Texas.
Originally submitted by: Tim S. Lee (first posted 2001-05-07)
Edited by: Kellie Whittaker, Tate Tunstall (2021-04-27)
Species Account Citation: AmphibiaWeb 2021 Eurycea tonkawae: Jollyville Plateau Salamander <https://amphibiaweb.org/species/5376> University of California, Berkeley, CA, USA. Accessed Sep 19, 2021.
Feedback or comments about this page.
Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Sep 2021.
AmphibiaWeb's policy on data use.