Present Threats and Future Prospects
This chapter looks at what we have learnt about sand dune management, conservation and restoration. It seeks to summarise the trends in human activity, setting their conservation requirements in a wider historical context. In particular, it looks at the way human use has constrained and changed the processes necessary for sand dune development, along the active coastal margin, and inland. It considers whether this and the extent of habitat loss have contributed to a protectionist philosophy, and a preoccupation with sand stabilisation. Have the timescales for assessing change and management need been too short? Learning from the past and looking to the future, it proposes a more dynamic approach for sustainable management and restoration for sand dune conservation.
KeywordsSand Dune Bare Sand Dune Slack Dune Mobility Coastal Sand Dune
12.1 Trends in Human Activity
Sand dune species, habitats and ecosystems are all adapted to coastal change both spatially and temporally. Human activity has sought to restrict the movement associated with this natural change, to protect assets established along the coastal margin from erosion and/or blowing sand. These assets include agricultural land (often derived from coastal habitats including sand dune), the built environment (ports and harbours, housing and industry) and coastal defence structures. As the coastal habitats are ‘squeezed’ from the land (Sect. 2.8), and sea by rising sea levels they have become less resilient to the forces acting upon them. Thus storms, where change can occur over minutes to hours, and even daily cycles of tidal inundation, cause erosion and drive the dunes landward. Hemmed in by housing, roads or other infrastructure and truncated by agriculture or forestry some sand dunes may eventually disappear altogether.
Fortunately, there are still substantial areas of coastal sand dune surviving around the world. What happens to them in the future largely depends on the availability of new sediment, whether or not they have ‘room to move’ and their management. Future trends in human use and the implications of climate change, particularly sea level rise, also have a significant bearing on this. It is clear that understanding the geomorphological context in which the development of a dune system takes place is essential when making management decisions. This applies to management and restoration in the face of changes taking place at a local level, as well as those related to regional weather patterns and worldwide climatic trends.
Several thousand years of historical human intervention have modified the sand dunes that survive in temperate regions today. In the past, we have perhaps not fully appreciated our role in influencing their physical structure and vegetation development. We now have a much better understanding of the processes that helped to create and nurture them including the influence, for better or worse, of human activity. At the beach/foredune interface changes in sediment availability are a key, helping to determine the response to exposure (waves, wind and rain) and sea level change ( Chaps. 4 and 6). The analysis of the vegetated states described above ( Chaps. 5 and 7) gives us an important insight into the role of grazing management in some parts of the world. The extent of mobile sand is another indicator of the impact of external factors such as sediment availability, exposure and human activity.
12.1.1 Agriculture and Forestry
The history of sand dune development is one of exploitation and habitat loss. Forestry plantations and agricultural development have been major factors in reducing the extent of open dune landscapes. New large-scale coniferous forestry planting on dune areas seems unlikely. However, the historical legacy of existing forests includes lowering of the water table (Sect. 7.5.2) and regeneration of an unplanned forest outside the planted area. These will continue to pose a threat so long as the forest remains in situ. However, in Denmark removal of large areas of forest, originally planted to combat erosion, is taking place. Despite opposition from some amenity interests, this is an ongoing activity both here and elsewhere in Europe with positive benefits for nature conservation (Sect. 9.7).
It is likely that most areas suitable for conversion to agricultural use are already in cultivation. Opportunities for further development are limited. Of more significance from a nature conservation perspective in northwest Europe, is the continuing move away from traditional farming enterprises and with it the reduction in grazing on many sites. This continues to pose a long-term threat. Atmospheric nitrogen deposition exacerbates the growth of coarse grasses and scrub encroachment as grazing intensity drops. At a smaller number of sites, the opposite is true and high stock levels cause loss of structural and species diversity, which in some instances can result in severe erosion. Thus, a key issue for the future lies in determining the appropriate stocking regime to meet nature conservation objectives, highlighted in Chaps. 7 and 9. This is particularly important where rabbits are no longer present or unwilling to graze unpalatable vegetation.
12.1.2 Recreation and Tourism
In the last 50 years, tourist development and recreational activity have had a continuing and increasing influence on the dune landscapes of Europe, notably in the Mediterranean, and in North America. Loss of dune areas has been on a large scale and cumulative. Urbanisation in Western Europe probably reached its zenith in Spain in the 1960s and 1970s. The pattern of development continued eastwards, along the Mediterranean coast and into the Black Sea, causing further loss of sand dune habitat in the European Union accession countries Romania and Bulgaria. Climate change could help mitigate some of these effects. Rising sea levels threaten low-lying coastal areas, whilst the increasing temperatures associated with climate change will require adaptive measures to be implemented (Nicholls and Hoozemans 1996). An analysis suggests by 2100 there could be a reduction in tourism in the Mediterranean, as summer visits become increasingly uncomfortable. However, despite this, tourism will continue to develop and tourist numbers grow, even if this growth may be substantially slower because of climate change (Bigano et al. 2008).
12.1.3 European Wars
Severe disruption took place on sand dunes such as those near Antwerp as they became part of the battlefield in World War I. During the Second World War, a further wave of damage occurred. The beaches of Dunkirk saw some of the greatest disturbance, with the evacuation of troops from the British Expeditionary Force in May/June 1940. In the months leading up to the allied invasion of Europe, sand dunes became places for military training. During this period, extensive physical damage took place, with destabilisation of many foredunes resulting from practice landing on the beach (Sect. 6.3.6).
Infantry training and the use of ordnance and other hardware on inland dune caused destabilisation on sites such as Braunton Burrows (Sect. 12.3.2). In the vast Łeba dunes, (Slowinski National Park) Poland, Field Marshal Erwin Rommel, Germany’s most famous military leader, apparently practiced desert warfare. Many other dune areas in mainland Europe suffered from military activities; not least the sand dunes on the Normandy coast where the D Day invasion by Allied Forces took place on the 6th June 1944.
These disturbances set the succession back many years. There was no intent to re-create mobile dunes as part of a process of restoration. However, it provided the foundation for the development of the systems so highly valued today for nature conservation, especially in northwest Europe. What would sand dunes look like if the disturbance had not taken place? It is likely there would be much less dune grassland or heath, and many more inland sand dunes would be clothed in scrub or woodland.
12.1.4 The Military and Management
Since the Second World War many sites used for training or directly affected by invasion or other military action, continue to support military use. Habitat loss occurs with military installations such as buildings or runways. At others the exclusion of grazing animals, because of the threat from ordnance, has resulted in a return to stability. When combined with the presence of alien species introduced to control erosion (e.g. Eskmeal Dunes Hippophaë rhamnoides, Sect. 8.3.1) large areas of open sand dune habitat can be lost to scrub encroachment.
The Netherlands, 50% of the total military estate of 30,000 ha and all firing ranges lie within Natura 2,000 sites;
Belgium, of the 26,000 ha of the total military estate, 70% is included in Natura 2,000 sites; 9,400 ha (12 sites) in Flanders and 8,000 ha (3 sites) in Wallonia;
Denmark, 45% of military areas (which total 32,000 ha) are included in Natura 2,000 sites (Gazenbeek 2005).
Some specific projects of positive benefit to nature conservation on coastal sand dunes occur in a range of European Countries. In Denmark, for example, a LIFE-Nature project involves a sand dune area used by the military, at Oxbøl. Here the Danish Armed Forces clear encroaching trees (including non-native trees, primarily Pinus mugo), and carry out “mosaic burning” in a few places (LIFE02NAT/DK/008584). In addition to this, they have also been engaged in the restoration of amphibian habitats and excavation of new ones, for the benefit of Natterjack Toad and Moor Frog Rana arvalis (Annex IV species in Habitats and Species Directive). Natterjack Toad is restricted to one of only three main locations in Denmark, the islands of Fanø and Rømø, the dynamic parabolic dune of the Råbjerg Mile and in the military training area of Oxbøl. Natural dune dynamics provide the necessary habitat for the species on the islands and the Råbjerg Mile. However, tank movement helps keep breeding and foraging habitats open in the military training areas.
At Vattaja in Finland, there is a comprehensive management programme, initiated to help protect the Natura 2,000 site, one of the largest Boreal (northern) sand dune systems in Europe. It also forms part of a European Union LIFE Programme study where military live firing and training go hand in hand with nature conservation aims (Koskela and Sievänen 2009).
In Spain a few of the more important and large populations of Maritime Juniper Juniperus oxycedrus spp. macrocarpa still survive in natural or semi-natural situations within protected or military areas (Muñoz-Reinoso 2003).
In Germany four inland military training areas not near the coast, are amongst the last large remnants of sparse, dry, sandy grasslands in Europe. For some specialist plants and animals, these are important refuges. Two species, Blue-winged Grasshopper Oedipoda caerulescens and Northern Dune Tiger Beetle Cicindela hybrida protected species in Germany depend on semi-stable sandy soils. Adults of the former require between 60% and 100% surface disturbance, corresponding to 50–70% plant cover, depending on the location. Adults of the latter preferentially occupy areas with >40% disturbance, or an average of 61% plant cover (Warren and Büttner 2008). Although these are not coastal sandy areas, they illustrate the significance of disturbance due to military activity for the conservation of such specialist animals.
Removal of scrub and less mature trees to help restore areas of dune heath at RAF Woodvale. Followed by chemical treatment, this included new stock fences and gates to link the area with the current grazing managed by Lancashire Wildlife Trust;
Introduction of grazing on large fenced headlands on Ministry of Defence (MOD) land and controlling willow re-growth in the dune slacks at Penhale Dunes with the Cornwall Wildlife;
At Eskmeals, Cumbria work includes Hippophaë rhamnoides control and reintroduction of grazing;
The Ministry of Defence erected 12 km of livestock fencing to facilitate the reintroduction of traditional grazing on the sand dunes of Magilligan and Ballykinler in Northern Ireland.
On the 208 ha Altcar Rifle Range estate, within the Sefton Coast Merseyside, northwest England, work included mowing to maintain orchid-rich grasslands and dune slack vegetation. Management of a series of shallow pools for Natterjack Toad and the creation of new wet slacks, were also part of the programme (Gazenbeek 2005).
12.2 Climate Change
Climate change will have important consequences for the physical and biological attributes of sand dunes and nature conservation values. To some extent, the precise effect will depend on sediment availability, the location and movement of the beach/foredune and the size of the inland sand dune. Larger systems with adequate sediment to create new dunes will be more robust than smaller ones (Doody 2004). However, changes in relative sea level are likely to have the greatest impact, especially for the beach/foredune. The potential for change on inland dunes is more difficult to assess.
12.2.1 Sea Level Rise and the ‘Sand Dune Squeeze’
Average global sea level is rising at approximately 3.2 mm/year nearly twice that experienced for most of the twentieth century. Some predictions suggest a rise of between 18 and 79 cm by the end of the twenty first century (Church and White 2006, 2011). When combined with an increase in the intensity and frequency of storms this is likely to have a significant impact on the shoreline, contributing to an escalation of global erosion trends (Brown and McLachlan 2002). However, there is considerable regional variation in sea level mainly due to differences in ocean thermal expansion (Cazenave and Llovel 2010).
Predictions of global eustatic rise do not tell the whole story. The interplay between isostic and eustatic movement is important in assessing the relative movement of sea level in relation to the land at a given location. Even in areas generally thought to be safe as glacial rebound outpaces risings seas, the coast is not necessarily secure. Isostatic uplift appears to contribute little towards mitigating the effect of relative sea level rise on the Scottish coast (Rennie and Hansom 2011). This may be even more significant on some of the outlying islands where the glacial cover was relatively thin when compared to the mainland and there is a relative rise in sea level (Sect. 11.7.1). The relative movement at the coast then depends on local conditions including sediment availability and coastal resilience. Areas with a reduced sediment supply (Sect. 4.2.1) may be particularly vulnerable.
In this situation, narrowing the zone occupied by colonising plants causes a breakdown of successional processes (Feagin et al. 2005). This will have knock-on effects for other interests. For example, a 0.5 m rise in sea levels could result in the loss of up to 32% of beaches in the Caribbean due to the vulnerability of coastal zones. This loss could have serious consequences for nesting sea turtles (Fish et al. 2005) and other interests present in the beach/foredune (Sect. 4.3).
12.2.2 Climate Change – Biological Effects
In temperate regions, vegetation plays a major role in halting or slowing down the movement of sand, when driven onshore by drying winds over an exposed beach. It is, therefore, important to consider the way in which a change in climate might affect the biological processes within the primary dune vegetation. Ammophila spp. and other sand-binding species respond to burial by sand. The extent to which an increase in temperature and wetness might affect the ability of these species to build dunes is difficult to assess. However, since both are especially adapted to overcome sand inundation it seems likely this factor will dominate any change in status. Any alteration of the balance of the species due to climatic factors per se is likely to be minor and difficult to detect.
It is also difficult to predict what factors might be most important for more stable inland dune vegetation. Drier summers and a rise in temperature resulting in drought conditions will cause changes in the structure and species composition, at least in the short term. However alternatively, greater winter precipitation could increase the rate of scrub development and help stabilise the system. Experience from the drought of 1976 in Great Britain suggests two principal affects on dune vegetation. Firstly, in dune slacks, there was a marked adverse impact on plants of special conservation interest. Secondly, there was also a significant lowering of the water table more generally (Rodda and Marsh 2011). The drought appears to have accelerated the gradual process of drying, which had been taking place for several years previously. This resulted in a loss of typical dune slack plants. It had an especially adverse impact on the rare Natterjack Toad as the dune slacks, important for breeding in the spring, dried out. Fire also causes damage, and dry summers may increase the incidence of burning of Ammophila arenaria and fixed dune grassland. In addition to causing changes in species composition, it can lead to the exposure of bare sand and severe erosion, with loss of sand from the system.
Species at the limits of their geographical range and with special habitat requirements may be the most responsive. Invertebrates, which are dependent on open dry, sandy substrates, could show the most rapid change. Hotter, drier summers, which lead to greater dune mobility, will tend to favour these species. Warmer wetter winters may on the other hand bring about more closed vegetation, causing a decline in the same species. Distinguishing this effect from the impact of changes in grazing regimes (Sects. 7.3 and 7.4) or nitrogen enrichment (Sect. 7.7.2) will be difficult. In order to separate climatic effects from anthropogenic impacts, historical information and contemporary management will need to be scrutinised.
12.3 Stabilisation – Too Much of a Good Thing?
Stabilising sand dunes as part of a restoration process is perhaps understandable when there is a threat to human assets from sand inundation. It is less obvious in areas where such interests are not threatened. However, in the 1950s extensive areas of many sand dunes had lost their surface vegetation, restoration became a priority and several sites in England are illustrative of the process. These sites show how ultimately this led to loss of nature conservation values and helped bring about a change in attitude to the role of sand dune mobility as part of the restoration process, especially on stable inland sand dunes.
12.3.1 Camber Sands – Recreation Pressure
Concentrated human use causes erosion which requires control when adjacent infrastructure is threatened;
The presence of car parks close by exacerbates these impacts, by facilitating easy access to the dunes and beach;
Remedial action can be costly;
Focusing on visitor control can result in other damaging changes such as alien scrub invasion.
12.3.2 Braunton Burrows – From Instability to Stability and Back Again
Braunton Burrows provides an insight into the importance of taking a wider view and longer-term perspective of management requirements when seeking to protect valuable wildlife assets. Extensively studied by ecologists in the last 50 years, it shows the way attitudes to stability have changed over the years. The American army trained for the D-Day landings here in 1944. This had a major impact on the stability of the foredune, where practice amphibious landings took place. Troop movements including the use of flamethrowers, mortars and vehicles such as tanks (Bass 1992) caused major destabilisation of inland dunes.
This proved to be very successful and by the 1970s a considerable area of the site was clothed in vegetation. This included dense scrub with Hippophaë rhamnoides reintroduced to speed up the stabilisation programme in the 1950s, following an earlier unsuccessful attempt in 1937. The loss of the rabbit population through myxomatosis in 1953, combined with a lowering water table due to drainage, were important factors in the stabilisation process (Packham and Willis 2001).
In the late 1980s, introduction of sheep grazing to several small enclosures attempted to demonstrate the value of this form of management in arresting scrub encroachment and restoring dune grassland. This had limited success and in the early 1990s, discussion about the introduction of cattle took place with the owners. These failed, and by September 1996 scrub encroachment was even further advanced and with it considerable loss of nature conservation interest.
Negotiations took place, but the nature conservation value of a large area of the site continued to decline. Between 1997 and 2003, mixed grazing by cattle and sheep took place in a small (27 ha) plot, confirming the value of this form of grazing in reversing the encroachment of coarse grasses and scrub and helping to re-establish species rich grassland (FitzGibbon et al. 2005). By 2009, the owners agreed to the reintroduction of cattle and began fencing three large enclosures to accommodate them. Military training continues.
This site shows how quickly vegetation can develop on inland sand dunes. It took only 20 years for most of the extensive areas of bare sand to become recolonised. Within a further 10 years, the adverse impact on the original nature conservation values, including species rich dune slacks, became apparent. It also confirms the importance of grazing as a means of controlling scrub and restoring dune grassland.
12.3.3 Blakeney Point – A Dynamic Spit
Blakeney Point is a shingle spit on the east coast of England with a series of recurves, partly covered by sand dunes at its distal end. Its inherent dynamism described in the early 1930s showed how it responded to changes in tides, storms and sediment movement (Oliver and Salisbury 1913). Bought by Charles Rothschild in 1912 at the suggestion of F.W. Oliver and given to the National Trust in the same year, it was the first nature reserve in the county of Norfolk.
12.4 Management Options
It is important when considering the management need to make a distinction between the beach/foredune sand sharing system and the inland dune. In the former mobile sand, ephemeral vegetation along the strandline and early dune-forming vegetation are inherently unstable. Many of the nature conservation attributes depend on this instability. In temperate regions, the inland dune develops into more stable forms, and vegetation plays a key role in the process ( Chap. 1). Here bare sand occurs because of deposition of sand blown inland from the beach or foredune, or through damage or loss of surface vegetation often caused by human activity ( Chap. 2). From a nature conservation perspective, the two systems appear to require different approaches. In the first, the best representation of nature conservation values occurs when the system remains active. The second depends on stability within the system for the full development of dune grassland or heath. However, as we have seen, too much stability can result in loss of nature conservation values.
12.4.1 The Beach/Foredune Interface
Eroding shorelines, i.e. those with limited supply of sediment or in locations with a relative rise in sea level, may elicit a response involving erosion control. On beaches with little or no vegetation and an eroding dune face (Figs. 4.2 and 11.7) or on those where the vegetated foredune is shifting landwards (Fig. 6.1) the underlying cause may lie outside the control of the local conservation manager. These include activities such as offshore sediment extraction (Sect. 6.3.1), sand mining from the foreshore (Sect. 6.3.2) or river damming (Sect. 6.3.3). Erosion may be partially reversible when governments are prepared to curtail these activities and/or initiate remedial action to restore the sediment supply, for example by beach nourishment (Sect. 9.2.7).
In the Netherlands where dune preservation is important for sea defence, since 1990, ‘dynamic preservation’ of the coast has become an integral part of policy. In this context beach nourishment, allowing natural dynamics to create beach/foredune barriers (Sect. 9.2.7) is an important management tool. Trade-offs associated with the creation of a more dynamic foredune system need not compromise their sea defence function (van der Meulen and van der Maarel 1989; van Bohemen and Meesters 1992).
12.4.2 Inland Dunes
In all but a few locations where local conditions result in accreting physical State 3 foredunes, those responsible for nature conservation often preside over a diminishing asset, as described above. Even on larger systems where losses are small relative to the size of the dune, there are significant management issues. These include control and removal of alien species ( Chap. 8), controlling scrub encroachment (Sect. 9.4), establishing the most appropriate grazing regime (Sect. 9.5) and managing recreational use (Sect. 9.6) including golf course development and management ( Chap. 10).
Of these, in temperate regions at least, scrub invasion at the expense of dune grassland and heath is probably the most significant. Four of the states of vegetated inland sand dune relate directly to the level of grazing pressure. The most frequently encountered on sand dunes of high nature conservation values, are those where grazing is absent or where it is at too low a level to control scrub development (vegetated State 4).
The reduction in nature conservation value, resulting from stability of these inland dunes, called into question the reliance on sand stabilisation as the primary policy for sand dune management. From the 1980s, coastal scientists began to suggest adopting a more flexible dynamic approach to sand movement, not only immediately above the beach in the foredune, but also inland (Doody 1989, 2001).
Since then there has been a change in attitude to valuing mobile features within the inland dune. This has meant that rather than expending energy on barriers to sand movement, the modern manager is more likely to embrace it as a feature in its own right. However, when is erosion a threat to the biological diversity of a sand dune? Of course, it all depends! A small site with little or no additional sediment might appear to be at risk of total destruction as the beach/foredune migrates inland, overwhelming the stable grassland or heath. This will be particularly acute for dunes backed by rising ground or infrastructure. On larger sites without such restrictions, the losses of vegetated dune may appear to be less significant.
In areas where there is an adequate supply of sediment for the formation of foredunes, the beach will continue to move seawards and with it the strandline and foredune. Locations with falling sea levels relative to the land are more likely to experience this form of progradation. As the inland dunes are ‘left behind’, in the absence of grazing they quickly become stabilised and scrub covered. There is a value judgement to be made as to the extent the vegetation succession should be allowed to revert to scrub and eventually become woodland (Sect. 9.3.2). However, even where grazing is present, there may still be a loss of important areas of grassland, heath or dune slacks with increased stability. In these circumstances, active promotion of instability may ultimately provide a more sustainable and cost effective way of promoting nature conservation. In terms of practical management, this could mean cutting down trees rather than planting them, and creating blowouts rather than preventing them.
These solutions, however, will require a more complete understanding of the dune system and the historical, physical and climatic context in which development has taken place. Clearly the larger the dune system the more opportunities there are for encouraging the full range of forms from bare sand, dune slacks, grassland and/or heath, scrub and woodland.
12.4.3 A Recreational Experience
Past human activities have resulted in widespread habitat modification and irreversible loss of sand dunes both big and small. At many locations, the surviving areas represent a depleted resource. There is legislation designed to protect both beach/foredune and inland sand dune from further damage and destruction. In the case of the former, this often recognises their contribution to sea defence. For the latter, nature conservation and/or recreational values provide the focus. Losses continue, and preventing further harmful development requires a more robust attitude by those responsible for implementing legislation affecting the coastal zone than hitherto.
At the beach/foredune interface, the lack of sediment is already significant. Due to the other factors involved, notably rising sea levels, a reversal of the predominance of erosion over accretion is unlikely without major intervention to restore sediment delivery to the coast. On a few coastlines, economic considerations make beach nourishment worthwhile. In many others, even some with developed shorelines, such intervention does not take place. The result is a narrowing foreshore, breakdown of successional processes and loss of vegetation and associated animals (Feagin et al. 2005). Where there are undeveloped inland dunes, the beach and/or foredune may continue to migrate landwards.
Whatever the status of the beach/foredune interface, the vegetated inland dune may continue to require prescriptive management. This will include scrub control, removing alien invaders, reintroducing grazing by domesticated stock and catering for visitors. Without such management, in Europe at least, most of the surviving areas of dune grassland and heath will continue to deteriorate, as stabilisation degrades their biological diversity. The most appropriate forms of management for nature reserves and other ‘protected’ areas, described in Chap. 9 continue to evolve. Based at Liverpool Hope University, the European Sand and Shingle Network facilitates exchange of experience amongst dune managers. Management can be labour intensive, costly and often restricted to individual problems. However, if we look to the past and consider the way sand dunes respond to environmental and human perturbations, alternative management options become apparent.
“The dune complex is a restless maze” so said Cowles (1899). It seems that in the intervening 100 years or so we have forgotten this fact and sought to stop blowing sand and control dune mobility. Ancient Acts of Parliament and Laws forbidding removal of Ammophila spp. and otherwise carrying out activities that cause destabilisation were relatively common. Forestry plantations, usually of non-native conifers stabilised areas of inland sand dune (Sect. 2.3).
The local demand for a ‘seaside holiday’ and the burgeoning foreign tourist industry in the latter part of the twentieth century meant cleaning beaches and creating car parks, access points, paths and tourist facilities (Sect. 6.3.4). Local planners and coastal managers failed to recognise the impact on beaches and inland dunes or, if they did, viewed the economic advantages as outweighing any environmental damage. They were more likely to provide finance to prevent sand dune erosion than control the activities that helped to create it. Chestnut paling fencing was, and continues to be, a means of controlling erosion along the coastal foredune (Sect. 9.2.4), around car parks and access points to the beach (Fig. 12.2).
Nature conservation organisations were similarly concerned with preventing sand movement. Sand fences became the first response to blowing sand, even in nature reserves where access was strictly controlled. Some nature conservation bodies continued to use stabilisation techniques such as fencing and Ammophila spp. planting (Fig. 12.5) until quite recently. However, as this book has demonstrated, in temperate regions vegetation is an extremely effective stabilising agent. There are far more examples of scrub infested inland sand dunes than mobile ones.
It is also true that destabilisation provides opportunities for habitat regeneration. Prof. Bill Carter said in 1990 at a conference in Sefton, England dedicated to dune conservation “these habitats are not sensitive but robust and designed to accommodate changes in tides, tidal energy and sediment availability. It is our desire to prevent them from moving that has caused so much damage”, personal recollection (Carter 1990). We sometimes forget that nature has a way of restoring itself if left alone. It may not be desirable to embark on the level of destabilisation in Europe, brought about during two world wars (especially the Second World War, Sect. 12.1.3). However, if it had not been for this disturbance, it is likely many more sand dunes would be clothed in dense species-poor scrub or woodland.
Thus, the tendency has been for the nature conservation movement to adopt the same approach as those concerned with protecting land and property. It was, and to some extent still is common practice to plant Ammophila arenaria, to thatch eroding dunes with brushwood or otherwise to stabilise bare sand using the techniques described in Sect. 9.2. During the 1980s, however, there was an increasing recognition that instability of inland dunes, as part of a natural process, plays a vital part in conserving sand dune biodiversity (e.g. Doody 1989). Conferences of the then newly formed European Union for Dune Conservation included further consideration of the theme (van der Meulen et al. 1989; Carter et al. 1992).
We must continue to manage some special areas to prevent loss due to stabilisation. However, we should also direct our efforts towards giving beaches and inland sand dunes, room to move. We must actively resist building new structures on inland sand dunes. Taking tentative steps to clear vegetation, reintroduce grazing and other relatively small-scale management at first, there is an increasing recognition of the value of techniques involving destabilisation. Although this will not be on the scale of earlier unplanned activities, nevertheless it does offer a longer term solution to the conservation of many of the important natural attributes of this highly prized habitat.
Increased storminess and other effects brought on by global warming will increase the erosive forces acting upon sand dune systems. We must resist the temptation to direct our efforts towards protecting them with traditional stabilisation techniques in either the foredune or inland, vegetated dune. A change in attitude, which recognises blowing sand as integral to the healthy functioning of a sand dune system, whether in the foredune or inland dune (Fig. 12.6) must continue.
Allowing greater mobility will help reverse some of the problems associated with stabilisation. In one sense, grazing is a secondary ecosystem/succession process, which has modified the sand dune species composition. Sediment movement, climate and soil forming processes are the basis for sand dune development. The restoration of sand dune dynamics could therefore, be an important management tool for restoring this habitat. Human use has been a significant agent of change in the past and could be in the future. Despite opposition to removing forests planted with alien species or remobilising stable dunes, these management options may provide a more enduring prescription for conserving this valuable habitat.
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