Dune and beach conservation and restoration

Beaches are strips of sand or shingle between the land and sea. Sand dunes are landforms that develop where there is an adequate supply of sand and where prevailing winds are strong enough for sand movement to occur (ref). They represent a dynamic spatial transition between terrestrial and marine ecosystems and occur worldwide from the tropics to circumpolar regions (ref). Sand dunes are naturally dynamic environments which are constantly changing in extent and form due to fluctuations in natural environmental forcing factors, such as winds, waves and tides (ref).

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Common on-site approaches to dune and beach conservation and restoration

Conservation and restoration of dunes and beaches involve similar processes. Further to minimizing disturbances, common on-site approaches include implementing physical barriers that trap sand, mechanically stabilizing dune ridges, and planting schemes using species adapted to the ecosystem to biologically fix or reforest the dune ridge (ref). More details on the broader range of issues that can affect success are presented on this page.

Dune and beach conservation and restoration as an EBA measure

Dunes and beaches are widely seen as a buffer between the land and sea and as providing important coastal protection and tourism opportunities. A range of conservation and restoration approaches have been developed to support these functions (including fencing of dune habitats and supporting the reestablishment of stabilizing vegetation), although few projects so far have had a focus on adaptation. 

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Where beaches are currently eroding, ‘beach nourishment’ has been used as an approach to maintain the beach profile, and involves depositing sand onto the beach from offshore or quarries. As beach nourishment can involve artificially building up sand on the shoreline, it can be seen as a more structural or hybrid adaptation approach.

Dunes provide coastal protection

Beaches and sand dunes can provide a barrier between the land and the sea. In particular sand dunes can play a vital role in coastal stability, protecting against coastal erosion and flooding (ref), two hazards that are predicted to increase in severity under climate change (ref). The porous structure of dunes absorb and dissipate wave energy and provide additional material which re-enters the marine transport system and forms a new beach profile after erosion events (ref). Dunes provide coastal protection by acting as a buffer from waves and storm surges, preventing storm waters from flooding low interior areas, as well as providing a reservoir of sand to nourish eroding beaches during storms (ref). Indeed, a mature dune system can eventually experience severe episodes of erosion during storm events, but if the sedimentary budget is at equilibrium, the sand will gradually be renewed or stored in an offshore bar, reducing future shoreline erosion. On an eroding coast, however, a stabilized dune will slow but not prevent shore erosion (ref). The wider and higher the dunes are between populated areas targeted for protection and the sea, the greater the level of natural erosion protection, in the form of buffering capacity, is provided (ref).

Dunes and beaches can support tourism

Beaches are an important tourist attraction, but they are also likely to be under increased pressure as the climate changes and sea levels rise. Maintaining beaches and related dune systems can therefore increase the resilience of tourism, and the livelihoods that depend on it, to climate change. 

Additional benefits

There may be benefits for biodiversity

Sand dunes represent unique and in some ways harsh environments for plant and animal life, and so the species associated with them tend to be specialised in nature and localised in distribution. Conserving dune habitat is therefore important for this specialist flora and fauna (ref).

Sand dunes contribute to water regulation and purification

Sand dunes play an important role in water regulation and purification, as coastal dune aquifers are an important source of water extraction (ref). 

Key issues that can affect success

Anthropogenic pressures

In recent centuries and decades, beaches and sand dunes have been significantly damaged by human actions and as a result are in decline, mainly due to coastal development and tourism recreation (ref). Coastal urbanization, for example, has in some cases destroyed dune systems, significantly reducing their capacity to supply sand during times of severe erosion, thereby increasing erosion risk. Additionally, dredging offshore can change beach profiles and so increase beach erosion. Managing these local, human-induced pressures is key to ensuring the success of dune conservation and restoration as an EBA measure.

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The need for space

An important consideration for the use of sand dunes in coastal erosion and flood defence is the need for space, as they require more space than conventional, ‘hard’ engineering structures (ref). The more space available between the sea and human-populated areas, the higher the efficiency of the system. This however may be challenging in highly populated coastal areas, and conflicts of interest may arise, especially if coastal sand dune restoration takes place in areas primarily used for residential or tourism purposes (ref).

On the ground dune stabilization implementation

Over the years, several measures have been applied to restore and stabilize dune systems and preserve their capacity to prevent coastal erosion and flooding. The success of the applied measure, however,  will mainly depend on local-scale environmental factors, such as patterns of wind and sand supply, among others (ref).

Vegetation planting techniques have commonly been used as a way to trap and stabilize sand blown from the beach, emulating the way coastal dunes are naturally created and maintained (ref). The plant species selected should originally be native to the region and be adapted to the harsh conditions present in dune environments. Transplantation in the growing season has been identified as a suitable approach (ref). 

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Vegetation planting can also be used in combination with soft physical structures to facilitate the establishment of a stable vegetation cover. Semi-permeable physical structures such as wooden fences or nets have been effectively installed to reduce wind speed across the sand surface and increase sand deposition (ref). Alternatively, natural materials such as brushwood or mulch can be directly placed onto the sand to increase surface roughness and provide a physical barrier to the wind (ref). However, since dunes formed by sand trapping devices may become unstable and highly vulnerable to changing wind conditions, it is common practice to further stabilize them with vegetation (ref), which further increases surface roughness so that more wind-carried sand will be trapped.

Local community involvement

Although to some extent dune management requires specialised knowledge and equipment, many aspects of dune conservation and restoration can be implemented at the community level (e.g. application of fences to stabilize bare sand, vegetation planting and maintenance; ref). The success of the community-led approach for vegetation planting has had varying success and is dependent on local commitment (ref), therefore local awareness raising campaigns may assist in promoting local efforts to protect dunes (ref). Creating policy measures which enhance the awareness, capacity and engagement across relevant stakeholders will support effective EBA outcomes; for more information on the importance of policy measures in adaptation, click here).

Beach nourishment

Although depositing sediments onto beaches can help maintain their presence in the face of erosion, it can also cause a number of negative environmental effects. Negative impacts include direct burial of animals and organisms residing on the beach, lethal or damaging doses of water turbidity (cloudiness caused by suspended sediments) and altered sediment compositions. As a result, projects must be designed with an understanding of, and concern for, the potential adverse consequences for the environment. See Linham and Nicholls (2010) in the Useful resources and materials section at the bottom of this page for more information.

Beach nourishment is also not a permanent solution; where it is being undertaken to compensate for net erosion of a beach it will provide a buffer to the erosion but not prevent the new sediment also being eroded. Additionally, if sediment is supplied by off shore dredging it can alter the profile of the seabed impacting waves and currents, as well as negatively impacting on the ecosystem being dredged.  

Useful resources and materials