My research in coastal Ecuador and the northern Gulf of Mexico (GOM)
elucidated differences in value of shallow estuarine habitats for fishes and invertebrates.
I focused on mangrove and tidal river habitats in Ecuador, and oyster reef, vegetated
marsh edge, and nonvegetated bottom habitats in the GOM.
Coastal Ecuador has lost 20-30% of mangrove wetlands over the past 30 years.
Such habitat loss can impair the ecological functions of wetlands. In this study I
identified the fish community of the remaining mangrove wetland in Rio Palmar,
Ecuador. For comparison, an adjacent tidal river without mangroves, Rio Javita, was
also sampled. I found that although Rios Palmar and Javita are characterized by
relatively low fish-species richness compared to other tropical estuarine systems, they
appear to provide important habitat for several economically- and ecologically-valued
species.
In the GOM, I examined the fish and invertebrate communities of adjacent oyster
reef (oyster), vegetated marsh edge (VME), and nonvegetated bottom (NVB) habitats.
Three main relationships emerged: 1) Oyster and VME provide habitat for significantly more species (as a measure of richness) relative to NVB; 2) Oyster and VME provide
habitat for uncommon and rare species; and 3) Many of the species collected in multiple
habitats occurred at higher abundances in oyster or VME habitat. Contrary to the current
low value ranking of oyster habitat relative to other estuarine and salt marsh habitats,
oyster provides high quality habitat for many species.
Understanding how key species utilize estuarine habitats is critical for future
conservation and management efforts. My research indicated that VME habitat may
provide better foraging options for juvenile pinfish (Lagodon rhomboides), and together
with corroborating evidence from other studies, suggest that VME provides a critical
nursery function for juvenile pinfish, especially in estuaries where seagrass habitat is
sparse or nonexistent. Additionally, I documented that juvenile white shrimp
(Litopenaeus setiferus) select for oyster habitat because of higher food availability and
not because of refuge needs from predation by blue crabs. Oyster habitat appears to
provide a nursery function for juvenile white shrimp. Overall, my research
demonstrated that structurally complex habitats, such as mangroves, VME, and oyster
provide essential habitat at the community, population, and individual levels.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1214 |
| Date | 15 May 2009 |
| Creators | Shervette, Virginia Rhea |
| Contributors | Gelwick, Frances |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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