Benthic communities in Spartina alterniflora and Phragmites australis dominated salt marshes

The benthic communities were investigated in Phragmites australis and Spartina altemiflora salt marshes, conducted in natural and mitigated salt marshes located in a highly urbanized area, the Hackensack Meadowlands, New Jersey. Benthic samples were taken with a 5-centimeter core at two habitats, the creek bank and the edge of the vegetation in the low marsh zone. Salinity levels and textural and structural sediment characteristics were also collected at each site. A recolonization experiment that utilized sediment from an undisturbed and uncontaminated salt marsh was conducted to determine if substrate is important in benthic colonization. The results suggest that there were differences in abundance, taxa richness, diversity, and composition in the benthic communities found among the different types of grasses as well as the mitigated and natural marshes. The Phragmites australis marsh had a more diverse benthic community than the natural and mitigated Spartina alterniflora marshes. The mitigated marshes had a greater abundance and lower diversity than the natural marshes. However, there were differences in salinity levels (oligohaline to polyhaline) between the mitigated and natural marshes that could result in different types of benthic communities. Substrate and contamination did not seem to be a factor in the recolonization of benthic communities. The principles of opportunism were responsible for shaping the benthic communities in the recolonization experiment. This study shows that Phragmites australis supports a healthy benthic community. The benthic community of the mitigated marsh did not resemble the natural marshes after 12-years of establishment