Shade and salinity in a coastal lagoon: What bugs the bugs?

摘要

During the summer of 2000, macroinvertebrate samples were collected during the initial phase of the upgrade of the levees along the San Lorenzo River, in Santa Cruz, California, to determine the effects of adding shade to a coastal lagoon system. Samples were obtained from three microhabitats influenced by tides in the lagoon: 100% fresh water, partial inundation by salt water, and constantly inundated with salt water. Overall, there was more diversity of species in freshwater reaches than in saline, and more individuals in shaded areas than in areas exposed to full sun. This data suggests that (1) due to salinity, an EPT (Ephemeroptera, Plecoptera, Tricoptera) index is not appropriate for determining water quality in a coastal lagoon; (2) adding shade to a coastal lagoon may increase the abundance and diversity of macroinvertebrates that are an essential food source for salmonids.