Dörte Neumeister Earlham College, Erin Lewis Earlham College, Olivia Honigman Earlham College
Faculty Sponsor(s): Brent Smith Earlham CollegeAmerican bullfrog tadpoles (Lithobates catesbeianus) play an important role in aquatic ecosystems as both primary consumers and sources of prey for other species. We investigated factors influencing bullfrog tadpole abundance in ponds within their natural habitat, we hypothesized that tadpole density and mass vary significantly among ponds and within microhabitats of ponds. Our prediction is that vegetative variation among different ponds, and microhabitat variations within ponds, will have an effect on the density and weight of tadpoles. We sampled six ponds using dip-netting to survey the population of bullfrog tadpoles in each. Tadpole density and weight differed significantly across the six ponds, two of which contained no tadpoles despite being in close proximity and accessible to egg-laying adult females in nearby ponds. One pond had dense duckweed cover (Lemna minor), which could have lead to high BOD and low tadpole survival. Another pond may have been lacking tadpoles due to small size, variable water quality, and limited cover. We also compared average tadpole weight and mass in microhabitats within two ponds. In one pond there was a significant difference between average tadpole weight among two habitat classifications. Sample sites dominated by algae had lower tadpole weight than sites dominated by American pondweed (Potamogeton nodosus). Results provide evidence to support the hypothesis that a variety of factors such as competition, vegetation, and eutrophication have an impact on fitness of bullfrog tadpoles, and suggest that other habitat factors such as shade and sediment type may contribute to differential tadpole survival among ponds.
When & Where
Gallahue Hall 101