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Palm Beach County Department of Environmental Resources Management GUIDELINES FOR PROPER BEACH AND DUNE MANAGEMENT NATIVE DUNE-FORMING PLANTS The beach and dune system is a dynamic environment subject to extensive change as a result of wind, waves, tides and storms. Native salt-resistant vegetation is essential to the beach and dune system as it both accumulates and stabilizes sand. Vegetation traps wind blown sand which collects around the plant and builds up the dune, a process known as “accretion”. As the plants become buried, new roots develop on the recently buried stems while new stems emerge from the sand. A dense stand of sea oats, and other primary vegetation in the foredune can significantly minimize erosion during high tides and storms. Sea oats are “protected” under regulations of the Florida Department of Environmental Protection (FDEP). Sea oats seeds can not be collected without a permit and the plants can not be cut back or removed. Sea grapes, which grow on the back dune and have large ping-pong paddleshaped leaves, act as a highly efficient barrier to blowing sand and result in significant accretion of the backdune. Dunes are important reservoirs for sand, replacing sand lost from the beach through erosion. All native dune vegetation should be protected from pedestrian traffic, pruned only as necessary and according to FDEP guidelines, and replanted as necessary to maintain this delicate system. DUNE SYSTEM Sea oats roots EXOTIC PLANTS Invasive exotic vegetation (i.e., Australian pine, Hawaiian half-flower, St. Augustine grass, wedelia, Brazilian pepper) should be eradicated from dune areas whenever possible. Invasive exotic species have a tendency to overgrow native species and are less effective in stabilizing the sand or maintaining the dune ecosystem. One of the most common dune invasives is the Hawaiian half-flower (Scaevola frutescens). The shallow roots and fragile stems of this exotic are easily destroyed in high winds or storms making it far less effective in dune stabilization than sea oats and other native species. It is important not to confuse this exotic with its native counterpart, inkberry (Scaevola plumieri) which is an endangered species protected by Federal law. The native inkberry has thick, round, rubbery leaves, and when fruit-bearing, the fruit is black in color unlike the exotic species which has snow white berries. EXOTIC: Hawaiian half-flower Australian pines inhibit the growth of other plants as a result of their shading effect and the acidic nature of their pine needles. Australian pines eventually results in a ‘weak spot’, making the dune vulnerable to storm erosion. In all cases where exotics have been removed, the area should be replanted with natives typical of that portion of the dune. Where lawn grasses adjoin the dune area, a distinct buffer zone should be maintained by herbiciding, mulching, and edging to control the ENDANGERED NATIVE: inkberry encroachment of these grasses into the dune. PRUNING NATIVE VEGETATION Trimming or pruning native dune vegetation may seem desirable to a property owner in order to provide a clear view. All trimming and pruning of sea grapes seaward of the Coastal Construction Control Line is subject to the permitting requirements of the FDEP. No more than one-third of the height of a sea grape and no more than one-third of the leaf area may be removed in a single pruning event or a single year. The plants can not be reduced to an overall height of less than six feet. All pruning should be in accordance with accepted horticultural practices referred to as “Crown Reduction Pruning Standards”. Any pruning beyond this limit requires an FDEP permit. A well-developed stand of seagrapes is essential to the stability of the beach and dune, accretion of sand, and protection of upland buildings from storm-induced erosion and blowing sand and salt spray. Sea grapes also block light from the beach where it could otherwise interfere with sea turtle nesting and disorient emerging hatchlings. Marine turtle mortality resulting from increased illumination is a violation of Florida Statutes and the Federal Endangered Species Act of 1973 and is subject to fines up to $10,000. The best policy is to let a hard winter freeze and salt spray control the height of dune seagrapes naturally. BEACH RAKING Beach raking can have negative effects on the beach and dune. Beach raking too close to the dune can destroy new seedlings establishing at the leading edge of the dune. Although seedlings in this pioneer zone often become buried by wind-blown or storm-deposited sand, they usually grow through the new sand layer and continue to stabilize the area. Beach rake operators should stay well away from the toe of the dune. Seaweed is valuable to the dune system as both a source of nutrients and a sand stabilizer. Seaweed removed from the beach should be deposited at the toe of the dune. Beach raking also reduces compaction of the sand which results in suspension of the sand in the water during high tides and contributes to loss of sand and erosion of the beach. Seaweed is a fertilizer and stabilizer IRRIGATION AND FERTILIZATION Healthy dune ecosystem In contrast to ornamental plants, dune vegetation is considered “xeric”, adapted to low water requirements. Excessive watering of the dune usually results in the establishment of undesirable, invasive exotics. It is therefore important that all sprinklers near the dune be adjusted to minimize overspray onto the dune. The nutrient requirements of native dune plants are generally low and fertilization can result in impacts similar to those caused by excessive watering. The best method to ensure an adequate nutrient supply is to leave all organic material such as leaf litter and seaweed in place on the dune. New plantings may require temporary watering until the plants establish a well-developed root system. RECREATIONAL ACTIVITIES Foredune plants are vital to sand accretion and building the reservoir of sand available to replenish the beach. These plants are also highly sensitive to disturbances. In order to protect these valuable plants, all recreational activities should be kept at least 10 feet away from the leading edge of the foredune. Recreational equipment such as boats, surfboards, beach chairs and cabanas should never be stored on the dune or within 10 feet of the foredune. Repeated disturbances to the vegetation will destroy the plants and weaken the dune system, leaving the beach as well as upland buildings vulnerable to storm damage. Following storm events, the change in beach profile should be noted. Has erosion occurred, or has sand simply been pushed higher on the beach covering previously exposed vegetation? In the case of the latter, recreational activities and cabanas should be kept far enough away from this location to allow the buried vegetation to re-emerge through the sand. PRESERVING YOUR BEACH Preserving the beach and the value of beachfront property depends on our understanding the significance of coastal sand dunes and our willingness to maintain the native vegetation critical to the functioning of this system. The actions you can take are: ! ! ! ! ! ! ! ! Protect and replant native dune vegetation. Eliminate invasive exotic vegetation. Trim and prune sparingly and according to FDEP guidelines. Avoid beach raking if possible or move seaweed to the toe of the dune. Avoid irrigating or fertilizing dune plants. Keep recreational activities and equipment well away from dune vegetation. Participate in restoring and maintaining your dune system. Call ERM with any questions you may have. Palm Beach County Environmental Resources Management (ERM) sponsors beach restoration projects throughout the County including dune restoration, beach nourishment, inlet sand transfer operations and construction of groins, breakwaters and other erosion control structures. Funding for these projects is obtained through County, State, Federal and local government. County funds for beach restoration and enhancement projects are primarily obtained through taxes paid by tourists on hotel and motel rooms in the County. Never underestimate the power of a storm. FOR MORE INFORMATION, CALL: Palm Beach County Department of Environmental Resources Management Environmental Enhancement & Restoration Division (561) 233-2400 OR VISIT OUR WEB SITE: www.co.palm-beach.fl.us Revised: September 2000