Ecological signatures of anthropogenically altered tidal exchange in estuarine ecosystems

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Ritter, A. F., Wasson, K., Lonhart, S. I., Preisler, R. K., Woolfolk, A., Griffith, K. A., … Heiman, K. W. (2008). Ecological signatures of anthropogenically altered tidal exchange in estuarine ecosystems. Estuaries and Coasts, 31(3), 554-571. doi:10.1007/s12237-008-9044-9
TitleEcological signatures of anthropogenically altered tidal exchange in estuarine ecosystems
AuthorsA. Ritter, K. Wasson, S. Lonhart, R. Preisler, A. Woolfolk, K. Griffith, S. Connors, K. Heiman
AbstractOne of the most conspicuous anthropogenic disturbances to estuaries worldwide has been the alteration of freshwater and tidal influence through the construction of water control structures (dikes, tide gates, culverts). Few studies have rigorously compared the responses of differing groups of organisms that serve as contrasting conservation targets to such anthropogenic disturbances in estuarine ecosystems. Elkhorn Slough in central California includes a spectrum of tidally restricted habitats behind water control structures and habitats experiencing full tidal exchange. To assess community composition for several different taxa in habitats with varying tidal exchange, we employed a variety of field approaches and synthesized results from several different studies. Overall, we found that communities at sites with moderately restricted tidal exchange were fairly similar to those with full tidal exchange, but those with extremely restricted tidal exchange were markedly different from other categories. These differences in community composition are likely the result of several factors, including restricted movement due to physical barriers, differences in water quality characteristics, and differences in habitat structure. Indeed, in this study, we found that water quality characteristics strongly vary with tidal restriction and may strongly influence patterns of species presence or absence. We also found that different conservation targets showed contrasting responses to variation in tidal exchange. Full exchange appears to favor native oysters, commercially valuable flatfish, migratory shorebirds, and site-level biodiversity. Minimal tidal exchange due to water control structures supports a suite of estuarine endemics (including the tidewater goby and California brackish snail) not represented elsewhere and minimizes invasions by non-native marine species. Altogether, our results suggest that total estuary-wide biodiversity may be enhanced with a mosaic of tidal exchange regimes. © 2008 Coastal and Estuarine Research Federation.
JournalEstuaries and Coasts
Start page554
End page571
Subjectsbiodiversity, biological invasion, bivalve, brackish water, community composition, comparative study, ecological approach, ecosystem management, environmental disturbance, estuarine ecosystem, flatfish, habitat structure, human activity, native species, restoration ecology, saltmarsh, tidal cycle, water quality, wetland management, California, Elkhorn Slough, North America, United States, Eucyclogobius newberryi, Gastropoda, Ostreidae, Pleuronectiformes
NoteCited By (since 1996):12, Ecology