PARENT SESSION
Tuesday, August 8, 5:00-6:30 pm
Poster Session 8 - Aquatic ecology
Exhibit Hall, Ballroom Level, Cook Convention Center
Indirect effects of green frog tadpoles (Rana clamitans) on the growth of Elodea canadensis.
Stamberger, Jamie*,1, Kershner, Mark1, Montemarano, Justin1, 1 Kent State University, Kent, Ohio, United States
ABSTRACT- Major primary producers in freshwater ecosystems include macrophytes and periphyton. Periphyton grows on macrophyte surfaces as part of the biofilm and can decrease light availability, possibly decreasing macrophyte growth rate. In other studies, freshwater snails reduce periphyton biomass through grazing, resulting in increased macrophyte biomass. Like snails, tadpoles scrape periphyton from macrophyte surfaces. To determine if tadpole grazing also affects aquatic macrophyte growth, we investigated the effects of green frog tadpole (Rana clamitans) grazing on the growth of the aquatic macrophyte Elodea canadensis in kiddie pools. Using a replicated regression design, we examined responses of Elodea biomass, periphyton biomass, and chlorophyll a along a tadpole density gradient. We predicted that as green frog tadpole (Rana clamitans) density increased, Elodea canadensis growth would increase due to increased light availability. However, final biomass of Elodea tended to decrease as tadpole density increased, possibly due to Elodea senescence, tadpole mortality, or the effects of Cladophora blooms. Interestingly, as tadpole density increased, Cladophora biomass decreased (R2 = 0.71). In contrast, Cladophora biomass increased with Elodea biomass (R2 = 0.72). While the role of tadpole grazing appears to be much more complex than originally hypothesized, further studies will focus on the role of tadpole-Cladophora dynamics in structuring macrophyte assemblages.
Key words: aquatic, primary production, Rana clamitans