The St. Johns River Water Management District has launched an experiment to transplant seagrass from healthy beds to barren spots at four locations in the northern section of the Indian River Lagoon. This experiment is part of the District’s Indian River Lagoon Protection Initiative, and is designed to provide a more complete understanding of the factors affecting seagrass health, mortality and recovery. This gained knowledge will provide a basis for development of action plans to facilitate the recovery of seagrass in the northern region of the lagoon.
The District partnered with Florida Atlantic University (FAU) to harvest small amounts of healthy shoal grass from the lagoon near Titusville and Vero Beach for transplanting to three barren areas — near the Pineda Causeway and near Melbourne in Brevard County, and near Wabasso in Indian River County. In addition, the Sebastian Inlet District transplanted seagrass at an additional location near Sebastian Inlet at the junction of Brevard and Indian River counties. Transplanting occurred in late July.
Seagrasses are the cornerstone of a healthy lagoon system, as well as a food source for manatees, and a nursery, refuge and foraging habitat for a variety of fish and other marine life. The loss of approximately 47,000 acres of seagrass in less than two years from the Titusville area south to Vero Beach prompted the District and other agencies to accelerate and expand efforts to improve lagoon health. The seagrass losses are believed to be the result of a massive “superbloom” that occurred in 2011 and a cycle of algal blooms since that time.
“We’re trying to determine why seagrasses are not returning to areas where water quality has improved and would support seagrass growth,” says Robert Chamberlain, a District biologist who is overseeing the experiment. “We are also assessing whether transplanting seagrasses is a viable option for recruiting and expanding grass beds in barren areas of the lagoon.”
Study sites are marked with white PVC pipes and contain four different study scenarios: a bare area that will determine whether seagrasses can return on their own, a plug of unprotected grass to show whether a transplant can survive relocation, a patch of grass protected from manatee foraging by a metal cage, and a space marked with only a stake. It is theorized that the stake will snag drift ing rhizomes — the term for seagrass plant stems — to see if they sink to the lagoon floor and take root.
Scientists will monitor the sites for two years and assess the survival, health and rate of transplant growth/spread, which is critical for determining recovery potential. FAU will provide an annual report and a fi nal report of the entire project. The final report will include conclusions regarding the feasibility of transplanting seagrasses as a large-scale recovery strategy.