Effects of Prescribed Burning on Amphibian Diversity in a Southeastern U.S. National Forest

Abstract

Abstract: Fire alters the abundance and diversity of many species, but its effects on amphibians are poorly known. We tested whether prescribed burning affected amphibian abundance and diversity within the Francis Marion National Forest, South Carolina, by monitoring assemblages at 15 temporary ponds with five different burn histories: 0, 1, 3, 5, and 12 years after burns. We also monitored terrestrial and aquatic environmental variables likely to influence amphibian diversity, such as leaf‐litter depth, pond water chemistry, and distance to neighboring ponds. Fire had significant negative effects. Immediate effects ( burning during the study ) explained 12.8% and 10.8% of the variation in anuran and amphibian abundance, respectively, whereas short‐term effects explained 31.8% and 24.6% of variation in amphibian species richness and evenness, respectively. Species richness increased and evenness decreased with time since burn, primarily because salamanders were rarely encountered at sites burned within 2 years. These sites had the shallowest leaf litter and highest soil temperature variances. Environmental factors unrelated to burning also significantly influenced amphibian diversity. Water chemistry explained 31.1% of variation in species richness, 32.2% of evenness, and>25% of anuran, salamander, and total amphibian abundances. Salamanders were most sensitive to water chemistry factors, particularly pH. Our results suggest that decreasing the frequency of prescribed burns from the current 2–3 years to 3–7 years will better maintain diverse amphibian and plant assemblages. Substituting growing‐season burns for the current practice of winter and spring burns would avoid repeatedly interrupting amphibian breeding and would maintain the desired longleaf pine community.