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MONITORING FOOD WEB CHANGES IN TIDE-RESTORED SALT MARSHES: A CARBON STABLE ISOTOPE APPROACH
Citation:
WOZNIAK, A. S., C. T. ROMAN, S. C. WAINRIGHT, R. A. MCKINNEY, AND M. JAMES-PIRRI. MONITORING FOOD WEB CHANGES IN TIDE-RESTORED SALT MARSHES: A CARBON STABLE ISOTOPE APPROACH. Estuaries and Coasts. Estuarine Research Federation, Port Republic, MD, 29(4):568-587, (2006).
Impact/Purpose:
to assess primary producer, suspended particulate matter, and Fundulus heteroclitus isotope values as indicators for changes in food web support functions in tidally-restored salt marshes
Description:
Primary producer (angiosperms, macroalgae, submerged aquatic vegetation), suspended particulate matter, and Fundulus heteroclitus isotope values (d13C , d15N, d34S) were examined to assess their use as an indicator for changes in food web support functions in tidally-restored salt marshes. Study sites, located throughout the southern New England region (USA), ranged from Spartina alterniflora-dominated reference marshes, marshes under various regimes and histories of tide-restoration, and a severely tide-restricted Phragmites australis marsh. Fundulus d13C values were greater for fish from reference Spartina marshes than for fish from adjacent tide-restricted/restored marshes where higher percent cover of C3 plants, lower water column salinities, and more negative dissolved inorganic carbon d13C values were observed. The difference in Fundulus d13C values between a tide-restricted Phragmites marsh and an adjacent reference Spartina marsh was great compared to the difference between marshes at various stages of tide restoration and their respective reference marshes, suggesting that food web support functions are restored as the degree of tidal restriction is lessened. While a multiple isotopic approach can provide valuable information for determining specific food sources to consumers, this study demonstrates that monitoring Fundulus d13C values alone may be useful to evaluate the trajectory of ecological change for marshes undergoing tidal restoration.