We determined the relative abundance, days of surface activity and indices of species diversity, evenness and richness for amphibians inhabiting three differently managed forests surrounding a Carolina bay in South Carolina following restoration. We collected animals daily for 3 y (Oct. 1993–Sept. 1996) using drift fences with pitfall traps in three forest types: loblolly pine (Pinus taeda), slash pine (P. elliotti) and mixed hardwoods (predominantly oak, Quercus spp. and hickory, Carya spp.). Captured animals were marked and recaptures were recorded but not included in statistical analyses, except in our evaluation of activity. We compared results to those of a more limited study conducted before restoration.
Amphibians were significantly more numerous and more active in the mixed hardwood forest than in the pine forest types. However, the hardwood forest had the lowest species diversity in 2 of the 3 y of the study. The slash pine habitat had the highest diversity in all 3 y and for the 3 y combined. Because the evenness index (J′) values differ in step with the species diversity index (H′) it appears that the evenness component of diversity, rather than the richness component, is what is determining H′ variation. A summer subset of these data and summer data from an earlier study of 1977–1978 is in marked contrast with yearlong patterns. For our summer data each forest type had the highest H′ value in one of the years of the study and again the J′ values parallel the differences in H′.
Large numbers of southern toads (Bufo terrestris) reduced evenness, and therefore species diversity, for all three habitats particularly the mixed hardwoods where this species was especially abundant. Proportionally lower numbers of B. terrestris in the summer samples increased J′ and H′ indices. Overall lower abundance and H′ values in the summers of 1994–1996 compared with 1977–1978 may be the result of habitat alteration during the restoration of the Carolina bay.