Creating Marshes with Dredged Material on a Restored Island in Chesapeake Bay

Abstract

Tidal marsh creation using dredged materials could compensate for losses due to a variety of anthropogenic activities, including higher rates of sea-level rise. However, initial seeding attempts failed in a newly created marsh in Poplar Island, MD. Hypotheses were that soils were too acid, too saline, too high in sulfides or seeds were not viable. In test plots containing mostly sand, amendments of dredged materials enhanced plant growth and survival. Furthermore pH was between 5.5 and 7, not low enough to inhibit growth of marsh grasses. Sulfides in pore water were very low (<20>µM). Soil moisture content limited production in plants growing under long photoperiods in summer conditions. Seed germination was zero in Spartina patens and decreased significantly in Spartina alterniflora at salinities greater than 10 and biomass was greatest in plants grown in low salinities (2.5 and 5).