SREL Reprint #3260

Terrestrial distribution of pond-breeding salamanders around an isolated wetland

David E. Scott1, Mark J. Komoroski2, Dean A. Croshaw3, and Philip M. Dixon4

1Savannah River Ecology Laboratory, University of Georgia, Drawer E,
Aiken, South Carolina 29802-1030 USA
2Swansea High School, Swansea, South Carolina 29160 USA
3Department of Biological Sciences, Florida Gulf Coast University, Fort Myers, Florida 33965-6565 USA
4Department of Statistics, Iowa State University, 2121 Snedecor Hall, Ames, Iowa 50011-1210 USA

Abstract: Terrestrial habitats surrounding isolated wetlands are a critical resource for many pond-breeding amphibian species, yet few studies have examined the terrestrial distribution of post-metamorphic juveniles and adults. We used an encircling drift fence at a breeding pond in conjunction with partial fences at 90, 172, and 332 m from the wetland to estimate the terrestrial distribution of adult marbled salamanders (Ambystoma opacum; four breeding seasons) and mole salamanders (A. talpoideum; two seasons), as well as the dispersion of newly metamorphosed A. opacum (one summer). For newly metamorphosed A. opacum, 79% emigrated <90 m from the wetland, and 8% moved beyond 172 m; movement distance was unrelated to body size. Distribution of adult A. opacum varied among years, with an average of 28% (range 23–31%) occurring beyond 172 m in all years. Averaged across two years, 51% of adult A. talpoideum occurred beyond 172 m. Lognormal models provided a good fit to both the juvenile and adult ambystomatid distributions, and parameters differed between age classes, sexes, species, and years within species. For adult A. opacum a buffer radius of 300 m or 340 m, depending on the year, is estimated to include 95% of adults; for A. talpoideum the estimate is 464 m or 501 m. A reanalysis of distribution data for seven ambystomatid species shows that a previous estimate of a 164-m radius to protect 95% of a population underestimates the needed buffer radius by 185 m. Because our study wetland requires a nearly 500 m wide radius to protect 95% of its ambystomatid adults, preservation of similar communities may require much more surrounding terrestrial habitat than previously thought.

Keywords: Ambystoma opacum; Ambystoma talpoideum; dispersal; isolated wetland; juvenile emigration; pond-breeding salamander; terrestrial buffer zone; terrestrial distribution

SREL Reprint #3260

Scott, D. E., M. J. Komoroski, D. A. Croshaw, and P. M. Dixon. 2013. Terrestrial distribution of pond-breeding salamanders around an isolated wetland. Ecology 94(11): 2537-2546.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).