My research was designed (1) to examine the role of predatory decapods as an organizing force in grassbed prey distribution and abundance patterns, and (2) to compare the importance of vegetation as a prey refuge with its importance in providing increased living space for prey populations in seagrass meadows. My approach was first to catalogue the feeding ecology of the larger shrimps and crabs in Apalachee Bay, Florida. This study revealed great overlap among trophic niches of the 14 decapod species examined, nine feeding categories based on different proportions of prey consumed by 25 age-related ontogenetic trophic groups, trophic niche similarity that was unrelated to taxonomic similarity, and that living plants, especially algal epiphytes, are more important in diets than has been realized. The pink shrimp, Penaeus duorarum, was clearly the most important predatory decapod. / After evaluating the predator-exclusion effectiveness of a new cage design by defaunating and monitoring faunal recruitment into cages during a 2-mo period of high predator densities, I initiated a 1-mo manipulative field experiment designed to test the refuge hypothesis. Replicate predator inclusion (treatment) and exclusion (control) cages were established across a vegetation gradient and Penaeus duorarum were enclosed in treatment cages. Cages successfully excluded larger decapods and fishes and a significant predation effect was detected for total densities of all major prey taxon groups in a simple (low plant biomass) habitat. The general consequence of increasing microhabitat complexity on the outcome of predator-prey interactions was a reduction in Penaeus effects on total prey densities across the vegetation gradient. Vegetation provided more protection for amphipods and mollusks than for decapods and polychaetes. These results extend the premise that vegetation affords protection for prey from the laboratory to nature. These experiments also reveal that living space (on vegetation) alone can account for microhabitat distributions of some grassbed fauna without invoking predation as a causal mechanism. / Source: Dissertation Abstracts International, Volume: 44-07, Section: B, page: 2041. / Thesis (Ph.D.)--The Florida State University, 1983.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_75160 |
| Contributors | LEBER, KENNETH MILES, III., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 185 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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