Beach Sunflower (Helianthus debilis) is a charming element in the dune system and attracts wildlife such as butterflies.
Coastal dunes are habitat for wildlife and support a high biodiversity of flora and fauna. They also keep beaches healthy by accreting sand and minimizing beach erosion rates. The dunes protect coastal infrastructure and upland properties from storm damage by blocking storm surge and absorbing wave energy. A healthy dune system is an invaluable asset to coastal communities like Miami Beach.
Native salt-resistant vegetation is a key component of a healthy dune system. Their stems trap and accumulate wind-blown sand, building up the dune and creating a sand reservoir for the system. Their roots stabilize the accumulated sand and significantly minimize erosion during high tides and storms. Additionally, during storms, the vegetation absorbs wave energy, blocks storm surge, and protects coastal infrastructure. Therefore, the long-term success of the beach and the upland properties is dependent on the health of the City’s dune system.
Dune Management
In 2014, the City of Miami Beach developed the “Miami Beach Coastal Dune Management Plan”. The purpose of this plan is to outline the framework and specifications that the City will use to foster and maintain a healthy, stable, and natural dune system. Utilizing this framework, the City manages the dunes as a natural system while maintaining a biologically-rich habitat for local species, is aesthetically appropriate for its location, and reduces or eliminates the need for future maintenance.
The City’s dune management strategy focuses on preserving the structural integrity of the dune. One component is the routine removal of invasive vegetation which grows aggressively, threatens the stability and biodiversity of the system, and does not provide the same benefits as native vegetation.
Hawaiian half-flower (Scaevola frutescens) is the most common invasive species found in the city’s dunes.
Another component of the city’s dune management includes working closely with Florida Department of Environmental Protection (FDEP) to protectdune vegetation from human impacts, including the species protected under FDEP regulations such as sea oats (Uniola paniculata) and sea grapes (Coccoloba uvifera). The City closely monitors the system to ensure that no trespassing or unauthorized work occurs and that any approved work in the dunes is conducted per FDEP regulations. All work proposed in the dunes must be coordinated with the City and must be vetted by the FDEP Coastal Construction Control Line (CCCL) field monitor.The most common invasive species in the City’s dunes is the Hawaiian half-flower (Scaevola frutescens), which has shallow roots and fragile stems that are easily destroyed in high winds or storms and make the species less effective in dune stabilization. The removal of Scaevola and other invasive species is conducted through a maintenance contract, as well as through volunteer restoration efforts, and is accompanied by the planting of native species. The City, in partnership with Fairchild Tropical Botanic Gardens and the Surfrider Foundation, has restored approximately 6.6 acres of dune habitat with volunteers since 2006.
Seagrape Trimming
Seagrape trimming is an essential aspect of dune restoration and maintenance. Per the Dune Management Plan, seagrapes should be initially pruned to reduce the crown height to 24 inches above grade, thereafter they are to be maintained between 36 inches and no greater than 42 inches above grade. The Environment and Sustainability Department and Public Works Greenspace Management Division carefully evaluate seagrapes that are taller than four feet and determines which can and should be maintained as either shrubs or coastal hammock. As such, vegetation adjacent to the beachwalk that provides shade to pedestrians are typically designated as costal hammock and are maintained as trees. While the trimming of seagrapes may appear drastic, they grow back quickly and fill in as shrubs. Overgrown seagrapes also pose a safety concern, as untrimmed dunes create desirable locations for vagrants and homeless encampments
Dune restoration is a vital component of the City’s dune management strategy. Restoration projects improve the health of the dunes, help to stabilize the dunes and improve overall coastal resilience by allowing native species to thrive. A healthy dune system provides significant nature-based protection from storms, climate change, and sea-level rise. Sections of the dune are over-run with invasive species or are in need of native species diversification. Since 2014, the Surfrider Foundation has conducted volunteer restoration throughout the dune system, including invasive removals and replacing them with native dune species. The City’s partnership with the Surfrider Foundation is a vital component of the City’s dune management strategy. Visit our events page for upcoming volunteer restoration events hosted by the Surfrider Foundation.
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