Author: Amanda L Subalusky,  Assistant Professor (University of Florida)

Description:
Terrestrial organic matter inputs can influence aquatic food webs through increased growth and production of aquatic insects. When aquatic insects emerge, they provide a feedback to terrestrial ecosystems. We tested the influence of organic matter inputs from large wildlife on aquatic insect emergence using an innovative portable, field-based experimental stream array. We compared the influence of animal feces from hippos, which has a high C:N ratio, carcass material from wildebeest, which has a low C:N ratio, and their interaction. We found that the emergence rates of Chironomidae and Simulidae were greatest in the hippo feces treatment, intermediate in the wildebeest carcass treatment, and lowest in the control treatment. The treatment with hippo feces and wildebeest carcass was not greater than hippo inputs alone. For Psychodidae, the emergence rate was highest for the wildebeest and the hippo + wildebeest treatments. These results suggest that animal resource subsidies can increase aquatic insect emergence rates, providing a feedback to terrestrial ecosystems, but the impact will depend upon the insect group and may be influenced by factors other than resource stoichiometry.

Category: Scientific Program Abstract > Special Session > SS13 Getting to the Bottom of Freshwater Food Webs: A Global Perspective on the Role of Terrestrial Resource Subsidies