The presence of different tree species around pond habitats could affect the quality of these habitats for amphibians. Trees can alter water quality as well as light and nutrient availability through canopy cover and the input the leaf litter into the pond. These effects may depend on the composition and diversity of the tree community. In this study we examined 1) does tree species type and diversity affect amphibian abundance? And 2) does the amount or type of leaf litter affect amphibian abundance? We sampled fourteen forested ponds (July and September) with 70% canopy cover that varied in the abundance of different tree species (Warren and Montgomery counties, Missouri). We measured the basal area of trees (50 cm of circumference or more) within 5m of the pond edge because these trees were assumed to contribute considerably to the leaf litter input in the pond. In each pond, we measured the amount of leaf litter and amphibian abundance in each pond using quantitative sampling techniques.
Results/Conclusions
We found a significant correlation between amphibian abundance and tree species diversity in July, but not September. Spotted salamander numbers were positively correlated with the percentage of red cedar and total tree species richness, but negatively correlated with the percentage of oaks. Gray tree frogs were positively correlated with canopy cover and the percentage of white oaks. Since canopy cover is also positive correlated with the percentage of oaks we are unable to distinguish which factor drives the abundance of tree frogs. There was no significant relationship between the amount of leaf litter in the pond and the abundance of amphibians. These results suggest that amphibian abundance in these pond habitats is affected by the presence of certain tree species. However, the mechanisms driving these effects require further study. Leaf litter may influence aquatic species like amphibians by altering the abundance of macroinvertebrates. Future studies will investigate the link between leaf litter, macroinvertebrates, zooplankton, and amphibian populations.
