What's Going on at Giacomini - in a Nutshell:
Tidal marsh mitigation and restoration projects are often accompanied by very quick changes in the numbers and types of fish using restored tidal wetlands, with much slower changes in the invertebrate community, particularly those that burrow in the mud. However, results from the first two years of monitoring after restoration of the Giacomini Wetlands shows a slightly different pattern. Prior to restoration, fish and benthic invertebrate communities in the Giacomini Wetlands differed considerably from those in natural marshes, although the less distinct separation between the dairy ranch and natural marshes for zooplankton communities may have been influenced by the slight hydrologic connection between diked and undiked areas due to leaking tidegates and culverts and levee overtopping during flood events. With restoration, both the zooplankton and benthic invertebrate communities responded strongly, shifting species assemblage to the point that some convergence with communities in natural marshes was apparent. Density of benthic invertebrates, which had quite low during ranching management, also climbed considerably, closely approximating numbers found in most of the undiked areas. Interestingly, shifts in species composition and increases in benthic invertebrate numbers did not necessarily result from heavy colonization by opportunistic, often non-native polychaete species that have been found in other newly restored systems. Primary benthic invertebrate taxa included oligochaetes and amphipods, the latter of which are associated with less polluted or disturbed systems. Fish communities appeared to respond the least to restoration, with graphic statistical techniques showing very little change between pre- and post-restoration species assemblages. What did change, however, was that the number of non-native fish and macroinvertebrate species dropped abruptly following removal of the levees.
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Last updated: February 28, 2015