Seagrass Restoration and Protection Strategies
Seagrass meadows, one of the most biologically productive and recreationally and economically valuable habitats in the world, provide vital feeding and nursery habitat for waterfowl, fish, shrimp, crabs and countless other estuarine species. Intact seagrass meadows also stabilize bottom sediments, prevent erosion, enhance water clarity and promote primary productivity throughout Texas coastal estuaries.
However, Texas seagrass meadows are threatened by dredging and dredge disposal, subsidence, and high nutrient loading from non-point source pollution. In addition, boat anchors and motorboats running across shallow vegetated areas create propeller scars that may seriously degrade seagrass beds. In Galveston Bay, where pressures from human development have been severe, nearly all seagrass beds (except in Christmas Bay) have been lost, so work now focuses on re-establishing lost seagrass meadows. In contrast, seagrass meadows in the Laguna Madre are still abundant but threatened, so work in that region focuses on protecting existing seagrass meadows. FWS Texas Coastal Program staff, along with other federal and natural resource agencies and non-governmental conservation groups are working cooperatively to apply the following restoration and protection techniques:
Planting seagrass by a specially designed pontoon boat that rapidly injects nutrients, plant growth hormones and sprigs of seagrass into the bottom substrate is far less time-consuming than hand-planting. In severely damaged areas, this specialized equipment can speed vegetative recovery. The equipment however, is expensive and only available from one Florida operator.
Hand-planting seagrass from transplanted sprigs is a time-consuming effort, often undertaken by staff with plenty of volunteer support. Propagules are anchored in the bay bottom using large staples or by planting in peat pots of bound root balls. No seagrass propagation facilities are in operation, so finding a suitable donor site where native seagrass can be harvested, without negatively impacting the natural habitat, can be challenging.
Releasing seagrass harvested from clogged industrial intake pipesmay prove to be an effective technique. In 1996, a U.S. Fish and Wildlife Service biologist collected seagrass from the intake pipes at a Corpus Christi power station and deposited the vegetation just offshore from Galveston Island State Park. Three years later, seagrass was found growing just inshore from the release site – the first time that seagrass has been re-established in Galveston Bay!
Limiting motorboat damage from anchors and propeller scars is particularly important in estuaries where seagrass beds remain common but are threatened by increased use of shallow draft boats. Prop scars not only destroy seagrass beds directly, but they may also hasten additional erosion near broken root mats. In Aransas Bay, the FWS Texas Coastal Program and Texas Parks and Wildlife Dept. worked cooperatively to improve channel markings that help boaters avoid seagrass beds. The two agencies also installed outreach signs at marinas and along channels, encouraging boaters to use designated channels. Similar work is being planned for the Laguna Madre.
These techniques for planting and protecting seagrass meadows are relatively new and are still being refined. The complementary skills and expertise of many collaborating partners is needed to develop, implement and monitor restoration projects so that we can determine which techniques are most effective in restoring and protecting the values of our seagrass meadows.