Conservation of young Southern leopard frogs should include forested habitats! [abstract]
Abstract
Throughout the world, amphibian populations have shown an overall declining trend. Frogs are a vital
part of the ecosystem, and their absence could have many negative consequences. However, if we are
to help conserve frogs, we must better understand their habitat requirements in all stages of life. Our
experiments simulated forest and field habitats using soils, grasses, and leaves and allowed Southern
Leopard Frog (Rana sphenocephala) metamorphs (very young frogs) to choose between the two. During
each trial, frogs were put into individual aquariums divided into two halves. The following three
experiments were conducted simultaneously: 1) forest soil plus intact litter vs. field soil plus intact
litter; 2) forest soil plus crushed litter vs. field soil plus crushed litter; and 3) wet forest soil plus intact
litter vs. dry forest soil plus intact litter. Frogs were left undisturbed overnight, and the next morning
we recorded which side they were on. Thirty out of 33 frogs (91%) chose the forested side in
Experiment 1. A lower number, 21 out of 33 frogs (64%), chose the forested side in Experiment 2.
Twenty-one of 22 frogs (96%) chose the wet side of Experiment 3. Because frogs are dependent on
moisture to survive, the results of Experiment 3 indicate that being in an artificial setting did not
affect the frog's abilities to make a choice. Therefore, the high number of forest choices can be
interpreted as a preference for forested habitats. Furthermore, the stronger selection for forest in
Experiment 1 rather than in Experiment 2 may mean that the frogs are choosing habitats based on
structure. For instance, dead leaves might provide much better cover from predators than matted
grass. Overall, these results show that conservation and management practices concerning the Southern Leopard Frog should include the forested areas around their breeding sites.