Hydrilla verticillata invaded south central Louisiana during the 1970s subsequently becoming the dominant submerged macrophyte in floodplain habitats of the Atchafalaya River Basin. The effects of hydrilla on littoral habitat structure, water quality, fish, and macroinvertebrates have been pervasive, and I hypothesized that dense hydrilla stands would also impact vertebrate predation on resident macroinvertebrates, although predation effects would likely be mediated by bed position. During 2003 and 2004, I conducted exclosure experiments in the Atchafalaya River Basin with artificial substrates to test for variations in hydrilla bed macroinvertebrate communities caused by predation, plant architecture, and bed position. To determine invertebrates consumed by fishes, I also examined stomach contents of potentially invertivorous fishes inhabiting these beds. Results indicate that position and predation are important in structuring macroinvertebrate communities, whereas plant architecture had little effect. My diet analyses indicate that the fishes sampled fall into three categories: 1) those that do not feed on macroinvertebrates; 2) those that feed on small invertebrates (e.g., dipterans); and 3) those that feed on large invertebrates (e.g., decapods) and poeciliid fishes. Further, the diets of the invertivorous fishes coincide with the distributions found in the macroinvertebrate community and, in general, those macroinvertebrates most commonly found in fish diets occurred in greater densities within the bed interior.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-06132005-163156 |
| Date | 14 June 2005 |
| Creators | Fisher, Jonathan C. |
| Contributors | William E. Kelso, James P. Geaghan, D. Allen Rutherford |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-06132005-163156/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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