paving the way for conservation?

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  • Paving the way for conservation? ANDREW F. BENNETT MP, MATTHEW R. BENNETT 8z PETER DOYLE

    Limestone pavement is a unique part of Britains physical landscape. Along with other forms of naturally weathered rock, it is under threat from exploitation for the horticultural market. Valued for its delicate and sculptured form, limestone pavement has been frequently used as decorative stone in rockeries and other landscapedground. If this unique landscape is to be protected, its exploitation must stop. Yet it must be remembered that the use of rock in gardens and landscaped ground has an important role in raising the public profile of geology within urban areas. W e have a simple message: the use of limestone pavement is wrong and must stop, but the use of other forms of stone in urban gardens is beneficial for the Earth sciences.

    ecently, attention has focused upon the Iid estruction of limestone pavement, one of the few unique aspects of Britains landscape. The removal of limestone pavement for use in gardens must stop if we are to conserve this rare resource. Yet the use of stone in gardens is beneficial to Earth-science conservation. Here we explore the background to these issues and make a case for the use of non-pavement stone in gardens.

    Limestone pavement is a unique aspect of Britains physical landscape. A geological phenomenon, its sculpted surface provides a unique habitat for rare plants, and is a major part of Britains contribution to the worlds natural heritage. Yet it is being destroyed at a terrifymg rate for use as decorative stone in gardens and landscaped ground.

    Rockeries have been part of British gardens for well over a hundred years, as gardeners have sought to mimic the intimate relationship of geology and flora through the use of natural stone. These rockeries have brought geology into our urban landscape, and have done much to raise the public profile of the Earth sciences, by introducing an unconscious awareness of geology. Rock gardens are constructed with a variety of stone and the majority do not use

    Fig. 1. (below) Spectacular area of limestone pavement in North Yorkshire with a runnelled morphology. (Note: In this and Figs 2-4, precise locations have not been given.)

    Fig. 2. (above) A typical area of limestone pavement with well-developed clints (blocks) and grykes (fissures), North Yorkshire.

    limestone pavement. However, weathered limestone is valued by horticulturists for its delicate sculptured form, and the demand is sufficient to cause the destruction of natural areas of limestone pavements, blocks of which sell at between L90 and El20 per tonne.

    The formation of limestone pavement Limestone pavement is irreplaceable, formed under a set of almost unique conditions. In northern England, Wales and Ireland, glacial erosion during the Quaternary Ice Age ex- posed Carboniferous Limestone and produced level platforms along bedding planes. After the end of the Ice Age, these platforms were left as limestone surfaces which were chemically weathered by rain and groundwater. The cal- cium carbonate which makes up the limestone is dissolved by acidic groundwater produced as carbon dioxide in the air and in the pore spaces

    98/0 Blackwell Science Ltd, GEOLOGY TODAY, May-June 1995

  • of soil reacts with water to produce a weak acid. This acidic solution has exploited joints and fractures within the limestone to give a pavement of blocks (clints) separated by fis- sures (grykes). The surface of these blocks is also sculptured into a variety of runnels and basins, known as karren. The detailed mor- phology of limestone pavement is very variable and is controlled by variations in the composi- tion of the limestone, the density and orienta- tion of the joints and the inclination of the bedding planes in relation to the pavement sur- face. As a consequence, the limestone pave- ment of the Yorkshire Dales is very different in morphology from that in the Pennines or that in South Wales.

    The Yorkshire Dales, the Lake District, the northern Pennines and The Burren in Ireland are the only places where extensive areas of this type of limestone pavement are to be found in the world. Water-worn limestone, karren, occurs elsewhere, but is not like that found in the British Isles. Nowhere else does the distinct morphology of the pavement exist. There are very few geologicaYgeomorph- ological phenomena which are truly unique to the British Isles; limestone pavement is one of them. It is not only an irreplaceable part of our landscape, but also supports a unique plant habitat.

    The conservation of limestone pavement Limestone pavement has long been under threat from human action - first, from farmers wishing to clear pavement blocks from their fields to improve its pasture and, second, from landscape gardeners in search of decorative stone for rock works. In 1981 its importance and the need for its protection was formally recognized in the Wildlife and Countryside Act

    Fig. 3. An area of undamaged limestone pavement in North Yorkshire. This contrasts with the adjacent area shown in Fig. 4.

    Fig. 4. An area of limestone pavement in North Yorkshire in which the surface blocks have been removed for use as garden stone.

    by an amendment championed by a number of MPs and conservationists, including one of us. This amendment established the Limestone Pavement Order, a process by which areas of pavement not protected as Sites of Special Sci- entific Interest (SSSI) could be notified as be- ing worthy of conservation to the County Planning Authority. Following the implemen- tation of an order, unauthorized destruction of a site can incur fines of up to E5000. The proc- ess of identifying and then protecting, via Limestone Pavement Orders, areas of pave- ment has only been pursued with vigour since the late 1980s by the Nature Conservancy Council, now English Nature, a process which continues apace today. In Ireland, where The Burren is world famous for its limestone scen- ery, the situation is even more perilous as little formal protection exists for its limestone pave- ment, although The Burren is now designated as a World Heritage Site. Further recognition of the importance of limestone pavement as a natural habitat came in 1992, when the Euro- pean Community Habitats Directive recog- nized limestone pavement as a priority both as a landscape feature and for its flora.

    Despite this level of recognition and protec- tion, limestone pavement is still under threat and is regularly exploited for the horticultural market. Some is legally quarried, as existing planning permissions are not negated by the introduction of Limestone Pavement Orders or Site of Special Scientific Interest status. Most, however, is removed illegally in a piece- meal fashion. The market value is sufficient to encourage the illegal removal of pavement blocks to fulfil specific commissions or orders. Blocks of limestone pavement are easily re- moved by a JCB scoop, or dragged off by chains, leaving behind a scar of broken and fractured limestone.

    0 Blackwell Science Ltd, GEOLOGY TODAY, May-June 1995199

  • Such action is clearly wrong and causes im- mense damage, but the clearest way to combat this is not through tougher conservation meas- ures or better policing but simply by re-educat- ing the consumer. In short, what is required is to remove the market for limestone pavement.

    The need to remove the market demand for limestone pavement has been recognized by the conservation community in recent years, and in particular by those looking for a high- profile campaign similar to that recently waged against the use of natural peat. The plight of limestone pavements is therefore an ideal fo- cus for the green movement and there has been a resurgence of interest in its protection (see Suggestions for further reading). Unfortu- nately, the message from the conservation lobby, particularly from organizations such as the Royal Society for Nature Conservation (The Wildlife Trusts) has been muddled and unclear, especially with regard to the use of stone in gardens. Whether by intent or igno- rance they have pushed the message that the use of any stone in gardens is wrong, whatever its source. This is simply not the case.

    We would like to set the record straight. The use of limestone pavement involves the destruction of a unique part of our landscape and should stop. The use of stone in gardens and landscaping is, however, ultimately benefi- cial to geological and landscape conservation and should be encouraged. There is a need to raise public awareness of natural landscapes and their geology in the urban environment where the majority live, but not at the expense of our unique landscape heritage. This is a view not only endorsed by ourselves but by Eric Robinson, Vice President of the Geolo- gists Association, founder member of the Limestone Pavement Action Group, and com- mitted campaigner for urban geology, who openly supports the use of non-pavement stone in gardens. It is important not to under- estimate the value to Earth-science conserva- tion that the use of stone in gardens can bring.

    Conservation is about informed public awareness. Over 80% of Britains population lives in urban areas. In order to raise the profile of geological and landscape conservation, tra- ditionally the Cinderella of nature conserva- tion, geology must be brought to the attention of the urban majority. One of many ways this can be done is by encouraging the use of stone in gardens and landscaped ground, particularly where it is used in a natural fashion. Some gar- deners are already advocating its use in a natu- ral fashion (Buczacki, S., Rocks and a hard placing, The Guardian, 7 January 1995), some- thing which has been suggested since the birth of rock gardening (Robinson, W., Alpine Flow- ers for English Garden


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