Macroinvertebrate community convergence between natural, restored, and created wetlands on the Delmarva Peninsula

Wetland restoration has become an increasingly important tool to reestablish important ecosystem services.  Biomonitoring of aquatic macroinvertebrates is a good technique to measure restoration success because these organisms often indicate habitat quality.  We gauged restoration success in a Delmarva Bay by comparing the macroinvertebrate communities of a natural pool, a restored pool, and a created pool in the Jackson Lane Wetland Preserve located in Caroline County, Maryland.  Our objectives were 1) to compare macroinvertebrate community similarity between historic, restored, and created pools through time, 2) to identify taxa with strong associations to each pool, and 3) to relate patterns of community composition to environmental characteristics.  Between 2005-2007 and again in 2012, we sampled macroinvertebrates and monitored environmental variables every month between March and August.  We then used Non-Metric Multidimensional Scaling and Dufrene-Legendre indicator species analysis to explore our data and address our objectives.  Our results show that the macroinvertebrate community composition differed between pools, especially in terms of primary consumer taxa.  Isopods (Asellidae) made up 54% of the total macroinvertebrate community in the historic pool, 12% in the restored pool, and was noticeably absent in the created pool.  Indicator species analysis grouped detritivores with the historic site, several predator taxa with the restored site, and three sub-families of chironomid midges with the created site.  Water chemistry between sites was initially different, although by 2012 the historic and restored pools became almost identical in terms of several important parameters such as pH, temperature, and dissolved oxygen. We believe that the relative abundances of the key taxa identified by our analysis are linked to restoration status and suggest differences in trophic structure between pools.