Meeting Abstract

P1.15  Friday, Jan. 4  Habitat preference of southern toads (Anaxyrus terrestris) in response to substrate salinity WALLACE, B.P.*; WELCH, A.M.; College of Charleston, SC; College of Charleston, SC bpwallac@g.cofc.edu

Selecting an appropriate habitat can be important for survival and reproductive success. Habitat selection is especially relevant for amphibians, a group that can be particularly sensitive to the environment due to their permeable skin. Human activities such as over-irrigation and road de-icing can lead to increased levels of salinity in the soil. These salinized habitats can be inhospitable to amphibians, because their permeable skin makes them subject to dehydration in hyperosmotic environments. We investigated whether female southern toads (Anaxyrus terrestris) can avoid slightly saline substrates by preferring non-saline substrates instead. Toads were individually placed in an arena in which the two sides differed only in substrate salinity. Salinity was manipulated by moistening the substrate on one side of the arena with brackish water and the other with freshwater. Time spent on each side and activity on each side, measured as the number of times the individual hopped or crawled, were monitored for two hours. At the lowest salinity level tested (4 parts per thousand), toads did not spend significantly more time on either side but did move significantly more when on the saline side. Toads may increase activity on the saline substrate in search of a more suitable, non-saline habitat. Tests using higher substrate salinities (6 and 8 ppt) will reveal whether toads show avoidance of salinity levels that pose a greater threat. The ability to detect and avoid saline soils may allow toads not only to find suitable terrestrial habitats, but also to locate appropriate low-salinity aquatic environments for reproduction.