Leaf litter from surrounding vegetation is an important source of energy to ponds. Natural litter substrates serve as a nutrient source for the aquatic food web, but changes in plant species composition can alter chemical features and nutrient dynamics in aquatic systems that subsequently impact aquatic taxa. The invasion of exotic species into forests can alter environmental resources in wetland ecosystems that serve as critical breeding sites for amphibians. Amphibians are one of the most threatened classes of vertebrates due to multiple factors, but little research has been conducted about the effects of non-native plants on the breeding sites and development of amphibians. It is important to investigate the factors that influence tadpole development because larval mass and timing of metamorphosis are closely linked to individual fitness. We investigated the input of both exotic and native leaf litter species on green frog, Lithobates clamitans, growth and development using a randomized complete block experiment. Eight leaf litter treatments, Pinus palustris, Quercus phellos, Lonicera japonica, and Ligustrum japonicum all with the presence and absence of tadpoles, were replicated five times for a total of 40 experimental units. We collected data on water quality, algal resources, and tadpole growth periodically during the experiment.
Results/Conclusions
We found that leaf litter species altered nutrient cycling that in turn affected the development of amphibian larvae, the mass, survival, and timing of metamorphosis. Exotic leaf litter produced up to a 300% larger larval mass than the native leaf litter, up to a 100% increase in the biomass of periphyton and phytoplankton, and an increase in total nitrogen and total phosphorus in the systems. Our results suggest that exotic leaf litter may increase the productivity of ponds and ultimately influence development in amphibian species. This research will provide insight into how exotic species removal might affect habitat quality and the maintenance of biodiversity at amphibian breeding sites.