Linking Hydrogeomorphology and Food Webs in Intertidal Creeks

Abstract

Intertidal creeks are shallow, photic ecosystems that potentially serve as sources of prey for many predators within estuaries. In a previous study, the link between nekton community structure and hydrogeomorphological variables for eight intertidal creeks was assessed for North Inlet estu- ary, South Carolina. Herein, we advance their findings through ecological network analysis of foodweb structure within two creeks and infer nekton trophic relationships to geomorphology and potential influences of hydrological condition and change. A summer network of a shallow, wide creek demonstrated greater carbon recycling, trophic effi- ciency and flow through consumers than that of a deep, narrow creek representing the same period. We infer greater export of nekton carbon from the former creek. These results were supported by analyses of nekton effective trophic levels and guilds across the eight creeks. Shallow, wide intertidal creeks appear to provide both physical and foodweb attri- butes that promote good nekton habitat relative to deeper and narrower creeks. Human alterations to flow regimes and sea- level rise have the ability to affect geomorphology of indi- vidual creeks and the landscape as a whole. These changes in turn have the potential to alter food webs of intertidal creeks and their ability to serve as sources of food for the larger estuary.