Contrasting Functional Performance of Juvenile Salmon Habitat in Recovering Wetlands of the Salmon River Estuary, Oregon, U.S.A.

摘要: For an estuarine restoration project to be successful it must reverse anthropogenic effects and restore lost ecosystem functions. Restoration projects that aim rehabilitate endangered species populations make success even more important, because if misjudged damage already weakened may result. Determining depends on our ability assess the functional state or performance trajectory of development. Mature system structure is often desired end point assumed provide maximum benefit for target species; however, few studies have measured linkages between function possible benefits available from early recovery stages. The Salmon River estuary, Oregon, U.S.A., offers a unique opportunity simultaneously evaluate several response marsh community while making comparisons with concurring undiked portion estuary. Dikes installed in three locations estuary during 1960s were removed 1978, 1987, 1996, creating space-for-time substitution chronosequence. Analysis responses enables us use development recovering marshes determine over 23 years reference marsh. We assessed rate pattern juvenile salmon habitat terms fish density, prey resources, diet composition wild Oncorhynchus tshawytscha (chinook salmon). Results outmigration 1998 1999 show differences densities, among four sites. Peaks chinook densities greatest site youngest (1996) 1999. 1996 had higher chironomids (insects; average 864/m 2 ) lower amphipods (crustaceans; 8/m 3 when compared other Fauna reflected diets those occupying 1978 based insects (especially chironomids), whereas 1987 crustaceans amphipods). Tracking emergent ecosystems reveals significant invertebrate first after restoration. This pulse productivity newly restored systems part indicates some level functionality efficacy restoring habitat. However, truly know consumers experience requires further analysis we will present forthcoming publications.