Omnivory and periphyton mats: uncoupling and quantifying consumer effects in the Florida Everglades
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 consu...
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| Format: | Others |
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FIU Digital Commons
1999
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| Online Access: | https://digitalcommons.fiu.edu/etd/3585 https://digitalcommons.fiu.edu/cgi/viewcontent.cgi?article=5009&context=etd |
| Summary: | 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. |
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