Bryozoans as ephemeral estuarine habitat and a larval transport mechanism for mobile benthos and young fishes in the north-central Gulf of Mexico
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In the northern Gulf of Mexico, bryozoans detach and concentrate in fall and winter creating a complex habitat offering local organisms a refuge from predation and/or a potential food source. The local reduction of salt marsh habitat acreage due to development, in addition to the well-documented loss of seagrass beds within Mississippi Sound, may increase the importance of ephemeral bryozoan habitat for a suite of young estuarine organisms. We collected 69 taxa or 2.75 organisms/g bryozoan wet weight between 7 October and 2 December 1999 (29 sampling dates) using three gears. Cluster analysis based on Jaccards Index revealed that offshore assemblages differed from onshore assemblages, and this pattern was also supported by quantitative similarity indices. Multiple linear regression indicated that of the seven abiotic variables measured, taxonomic density shows a positive relationship with turbidity and taxonomic richness a positive relationship with turbidity, distance from shore and bryozoan dry weight. Collections yielded a greater taxonomic richness than 82% of studies on other complex ephemeral habitats, many of which were of a longer duration, involved more intense sampling, or which were conducted on other ephemeral habitats associated with highly vegetated seascapes. Ephemeral bryozoans which occur annually along a muddy-bottom landcape in the north-central Gulf of Mexico serve a role as a nursery habitat and a dispersal mechanism as has been shown with other ephemeral habitats like Sargassum and drift algae.
KeywordsSalt Marsh Jaccards Index Taxonomic Richness Marsh Habitat Nursery Habitat
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