Lignumvitae Key Submerged Lands Management Area and State Park encompasses 8,400 acres of shallow water seagrass meadows surrounding Indian Key, Shell Key and Lignumvitae Key. Seagrasses form the structure for one of the Keys’ most vital marine habitats. They stabilize the bottom, filter sediments from the water, and provide food and shelter for much of Keys sea life. Boaters damage Lignumvitae’s seagrass banks when they stray from the narrow winding channels and run aground. Boat propellers tear holes in the lush green seagrass beds causing fragmentation, erosion, and loss of water clarity. Each year acres of seagrass habitat are lost at Lignumvitae due to boating impacts.