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LINKS BETWEEN MARSH, NONVEGETATED, AND SEAGRASS HABITATS IN A PRISTINE VIRGINIA SYSTEM
Citation:
Cicchetti, G AND Diaz. LINKS BETWEEN MARSH, NONVEGETATED, AND SEAGRASS HABITATS IN A PRISTINE VIRGINIA SYSTEM. Presented at Estuarine Research Federation '99, New Orleans LA, September 25-30, 1999.
Description:
Abstract: We describe habitat linkages in a narrow, contiguous marsh-nonvegetated seagrass system as is found bordering many undeveloped shorelines. Nekton were quantitatively sampled in eight spatial/tidal subhabitats on a Spartina-nonvegetated- Ruppia gradient using 1.75 m2 drop rings (York River, Virginia). Most individuals (65%) and biomass (86%) collected were species that used all three habitat types at different tidal stages. Guts were examined, and calculations were developed to estimate consumption and predation in each habitat by combining feeding information with population data. We quantified export as predation (biomass removed) by nekton
species that are transient to these areas. We showed interconnections within this shallow system by examining tidal movements of resident nekton, especially fundulids. Each habitat contributed importantly to overall trophic functioning. Marsh interior areas facilitated efficient consumption of invertebrate prey. Gut analyses implied that marsh edge provided foraging for small blue crabs and other nekton on the nonvegetated side, and refuge on the vegetated side. Nonvegetated areas offered high infaunal biomass and low tide refuge, as did seagrass. All habitats were linked by nekton that followed the tides and moved energy from shallow to deeper waters. The intricacy of between-habitat connections suggests that these intertidal areas should be protected from habitat fragmentation.