Omnivory and periphyton mats: uncoupling and quantifying consumer effects in the Florida Everglades

Authors

Pamela Geddes, Florida International University

Document Type

Thesis

Degree

Master of Science (MS)

Major/Program

Biology

First Advisor's Name

Joel C. Trexler

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Jennifer Richards

Third Advisor's Name

Sue Perry

Date of Defense

7-21-1999

Abstract

The role of omnivores in structuring communities is poorly understood. I studied the effect of two abundant omnivores, grass shrimp (Palaemonetes paludosas) and eastern mosquitofish (Gambusia holbrooki), on periphyton biomass of the Florida Everglades. I performed field experiments to test for consumer top-down and “complex” top-down effects on periphyton biomass. My experiments suggested that shrimp and mosquitofish had consumptive effects on periphyton but in many instances, periphyton wet weight, AFDM, and chlorophyll a increased significantly with shrimp or fish density, suggesting compensation by nutrient regeneration or trophic cascade processes. I propose that characteristic periphyton mat structure and integrity deters herbivory and affects the outcome of the periphyton-consumer interaction. Results from a descriptive study and a laboratory experiment support this hypothesis. Overall, consumption by shrimp and mosquitofish was significant, but coupled with and sometimes compensated by “complex” top-down effects, making these consumers “functional” omnivores.

Identifier

FI15101547

Recommended Citation

Geddes, Pamela, "Omnivory and periphyton mats: uncoupling and quantifying consumer effects in the Florida Everglades" (1999). FIU Electronic Theses and Dissertations. 3585.
https://digitalcommons.fiu.edu/etd/3585