Maintaining a Healthy Dune Ecosystem
The City of Delray Beach’s municipal beach is approximately 6,450 feet long and it contains a natural dune system that is actively managed by the City to balance wildlife, recreational, aesthetic and storm protection needs.
Our dunes are on average 160 feet wide and actively accumulate sand and provides habitat for numerous plant and animal species. The City recognizes the importance of this habitat and seeks to continuously improve the health of the dune system.
The City developed a Dune Management Plan in early 2020 that included an assessment of the seagrapes and other plant species along the municipal beach utilizing RTK GPS. The assessment recorded the approximate height, width (west to east) and length (north to south) of the seagrapes along the entire survey area and provides the basis for development of a recommended dune maintenance and trimming plan. The plan strives to enhance the health of the dune system and promote strength and species diversity.
Native plants that make a natural dune system
The zones of a natural beach and dune system in south Florida include the submerged, intertidal and upper beach, foredune, coastal strand/scrub zone, and maritime hammock.
Closest to the ocean is called the foredune, which is occupied by herbaceous plants – primarily sea oats, but you will also find bitter panic grass, cordgrass and several other species.
Past the foredune, the coastal strand zone is a wide area dominated by sea grapes, which make up a substantial portion of the dune width. The sea grapes play a major role in stabilizing the beach and dune system and facilitate accretion by storing sand in the dunes.
Between the sea grapes and the sidewalk, saw palmetto, cocoplum, buttonwood, and sable palms are also found.
Approximate length (in feet) of municipal beach
City beachfront parks
Seagrape Trimming Plan
After development of the Dune Management Plan, a CCCL permit application to implement the recommended maintenance and trimming plan was submitted the Florida Department of Environmental Protection (FDEP). Anticipating the issuance of the permit, the first semi-annual trimming activities are tentatively scheduled to commence the week of June 22, 2020. Based on the plan and submitted permit application, the City is requesting to perform trimming along the entire Municipal Beach. FWC is requiring that the City perform the initial trim in most areas of the beach no lower than 36 inches. In the commercial area, the sea grapes will be trimmed to 42 inches.
Recommendations included in the plan include the removal of exotic vegetation, planting native Dune vegetation, and continued maintenance of sea grape height. For the majority of the Municipal Beach, following the initial trimming of the sea grapes, the shrubs will be maintained at 36 to 48 inches accomplished in twice-yearly trimmings. The trimming will mimic the natural shape of the plants. For plants that were trimmed approximately three years ago, the trimming will be back to the 42 to 48 inches in height and will be maintained at that level. Because sea grape has been so successful in the City’s dune, it is necessary to reduce the expansion of the seagrape by removing it from the foredune and also in several places where it is attempting to take hold and out-compete native plants. The goal is to replicate the historic coastal strand growth form, improve storm resilience and to control lateral spread.
Several areas of tall sea grapes are recommended for retention at this height to provide examples of Maritime Hammock, which is important as resting and feeding sites for migrating songbirds. In some locations the taller sea grapes provide a buffer preventing lighting from reaching the beach and potentially having an adverse effect on marine turtle nesting.