Sand dune stabilization is a coastal management practice designed to prevent erosion of sand dunes. Sand dunes are common features of shoreline and desert environments. Dunes provide habitat for highly specialized plants and animals, including rare and endangered species. They can protect beaches from erosion and recruit sand to eroded beaches. Dunes are threatened by human activity, both intentional and unintentional (see sand theft and sand mining). Countries such as the United States, Australia, Canada, New Zealand, the United Kingdom, and Netherlands, operate significant dune protection programs. Stabilizing dunes involves multiple actions. Planting vegetation reduces the impact of wind and water. Wooden sand fences can help retain sand and other material needed for a healthy sand dune ecosystem. Footpaths protect dunes from damage from foot traffic. The location of the dune limits the types of plant that can thrive there. Beach dunes consist of the foredune, the angled side which faces the ocean, the sand plain at the top of the dune, which may or may not be present, and the backdune, the angled side that faces away from the ocean.
Foredune flora Plants that thrive on the foredune must be tolerant to salt spray, strong winds, and burial by blowing/accumulating sand. Examples of beach and foredune vegetation of temperate zones include Ammophila arenaria (an invasive species on the west coast of North America), Honckenya peploides, Cakile maritima, and Spartina coarctata.
Backdune flora Plants which thrive on the broad dune plain and backdune grow together into dense patches termed "dune mats" that hold the dune together. Examples of temperate zone flora of the plain and backdune include Hudsonia tomentosa, Spartina patens, Iva imbricata, and Erigeron glaucus. Introduced species can out compete native plants and disrupt animal life, making them formally "invasive species".
Shrub stage The above species are herbaceous plants. After they have rooted and developed fully, a second stage, the "shrub stage", can begin. During this phase, larger plants with deeper root systems can be planted. Examples are Empetrum nigrum, Ilex vomitoria, and Vaccinium ovatum. The shrub stage is variable depending on microclimate, and may be influenced the height of the water table, wind and salt spray. The shrub stage may eventually give way to forest or chaparral.
Coastal management A single beach may be divided into segments with different owners. Gaining agreement among all owners complicates the process of stabilizing the dunes. Without agreement, some parts of the dune may go unplanted, while others host visually appealing plants that do little to stabilize the dune. Inconsistent vegetation, known as a fragmented or decoupled gradient, can create weak points in the dune that limit its effectiveness against floods and even its continued existence. Publicly owned beaches, found in U.S. states such as California and Hawaii and in other jurisdictions, present the opportunity to systematically manage—or mismanage—beaches and their accompanying dunes.
Coastal sand dune management
Coastal sand dunes fringe thousands of kilometres of coastline around the world. They are made up of continuous, hummocky hills of sand that are held together by specially adapted sand dune vegetation. See Figure 1. These plants have adaptations that allow them to survive in sand dune habitats, these include adaptations to a moving substrate which covers and uncovers its roots, adaptation to desiccation, to strong winds carrying salt and sand and to wildly changing temperatures. Coastal sand dunes formed during a time of low sea level where sand and sediments on the foreshore became exposed and in conjunction with sufficient winds, this sand was transported up the beach face via a process known as saltation. Once sufficient wind (>15 km/h) mobilises sand particles they become trapped in vegetation or drift wood at the back of the beach, sand then continues to accumulate among the vegetation and over time slowly builds up the dunes we see today. Sand dunes serve an important purpose by protecting inland areas from coastal water intrusion. They are able to absorb the impact and protect inland areas from high energy storms and act as a resilient barrier to the destructive forces of wind and waves.
Human impacts
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