Benthic Communities in Spartina alterniflora– and Phragmites australis–Dominated Salt Marshes in the Hackensack Meadowlands, New Jersey
by Catherine E. Yuhas,¹ Jean Marie Hartman,² and Judith S. Weis³
¹ New Jersey Sea Grant College Extension Program, New York-New Jersey Harbor Estuary Program Office, 290 Broadway, 24th Floor, New York, NY 10007
² Rutgers University, 93 Lipman Drive, New Brunswick, NJ 08901
³ Department of Biological Sciences, Rutgers University, 411 Boyden Hall, Newark, NJ 07102
Phragmites australis is invasive in Atlantic coastal salt marshes and often replaces the native cordgrass, Spartina alterniflora. Our research focused on benthic communities found in natural and mitigated P. australis and S. alterniflora salt marshes at two sites, Sawmill Creek (natural sites) and Mill Creek (mitigation sites) in the Hackensack Meadowlands, New Jersey. The area sampled at the natural sites consisted of adjacent stands of P. australis (P) and S. alterniflora (S) separated by a tidal creek. At Mill Creek, samples were collected at a 12-year-old mitigation site consisting of S. alterniflora (M-12) and a newly mitigated site (M-0) where site regrading had just taken place. Benthic samples were taken at the creek bank and the edge of vegetation for all sites. Data on salinity levels and textural and structural sediment characteristics were collected at each site. Our data indicate that both the P. australis and S. alterniflora sites support diverse benthic communities, although there were differences in diversity and composition in the communities found among the different types of grasses. The average abundance of benthic invertebrates at the Sawmill Creek natural sites ranged from about 35,000 per square meter (/m²) to over 240,000/m². Taxon richness was ∼10 at P and ∼7 at S and the P. australis site had more common taxa present (1.0% of the total abundance). Average abundance of benthic invertebrates at the Mill Creek mitigation sites ranged from about 130,000/m² to 3 million/m². Taxon richness was ∼10 at M-12 and ∼7 at M-0. This study suggests that significant change has not occurred at M-12 in the low marsh since the commencement of the mitigation in 1988.
Key words: Benthic invertebrates; estuarine ecology; Hackensack Meadowlands; low marsh; Phragmites australis; salt marsh; Spartina alterniflora; tidal estuary