Experimental Studies of Predator and Prey Interactions

Project Investigators: William Loftus, Joel Trexler Project Personnel: Shawn Liston Project Start Date: 1996 End Date: 2002 Project Summaries Publications

Summary

The objectives of this cooperative effort of FIU, USGS, and NPS, are to address questions about predator-prey, competitive, and indirect interactions.

This multi-year program embodying facility construction, maintenance, and experiments is nearing the end of its funding cycle. The experimental mesocosm array was constructed in Everglades National Park as a cooperative effort of FIU, USGS, and NPS to address questions about predator-prey, competitive, and indirect interactions difficult to study in the field. Two experiments that examined mosquitofish predation and competition with other cohabiting small fishes in the Everglades marshes have been completed.

Results showed that growth of juvenile mosquitofish could be limited by the presence of other juveniles at densities within the range found in the Everglades. This suggests that food limitation is a potential factor for juvenile fishes in Everglades marshes, as had been suggested by earlier field studies. The relative role of food versus predator limitation is central to any model of fish population dynamics, such as the ATLSS model.

We have completed the study of spotted sunfish nest predation by small fishes, especially mosquitofish, which demonstrated a feedback loop in the Everglades food web. Mosquitofish prey upon eggs and larvae of spotted sunfish, which in turn eat mosquitofish as they grow. Water level was inversely related to the degree of nest predation and probably helps explain why sunfish populations grow during high water years. The mesocosm is now being used to address the role of nutrient inputs into the Everglades in causing shifts in marsh food webs.

Project Summaries

• 2001
• 2002

Publications

Bibliographies

• Experimental Studies of Predator and Prey Interactions - Bibliography

Flyers

• Studies of aquatic community structure and dynamics in the seasonally variable wetlands of southern Florida (available from the Center for Aquatic Resource Studies website. Please note that this is a (0.2 Mb) PDF file and requires the FREE Adobe Acrobat Reader® to be read)