Map India 2000 - Poster :Integrated GIS And Airborne Remote Sensing -- A Tool For Coastal Conservation And Management In South Wales, UK

Study Area
Kenfig dunes and NNR (Figure 1), with an areal extent of about 650 hectares, contains 575 species of flora of which 550 are native to the UK. Of these, 50% are Welsh flora, 23 of which are nationally scarce. Presently, however, Kenfig is undergoing a reduction of biodiversity due to the over-stabilization of the dune system and as a result : (i) there is acceleration of succession towards a dune-heathland climax status by expansion of vegetated areas at the expense of mobile sand areas; (ii) sand mobility has almost stopped; and (iii) surviving pockets of the original dune habitat are fragmented/isolated (Davies 1995).

The significance of this loss of biodiversity is best highlighted with respect to a number of plant species: First, Kenfig NNR is the British stronghold of the rare and declining fen orchid, Liparis loeselii, supporting more than 95% of the total British population. This species, threatened throughout its European range, is the only higher plant occurring in Britain to be listed as a priority species in Annex - II of the original EC

Figure 1. Map showing the location of the Kenfig National
Nature Reserve, UK, chosen for the present study.

Habitats and Species Directive. It was also listed as requiring protection by the Bern Convention 1992, and is on Schedule 8 of the Wildlife and Countryside Act, 1992. Regrettably, it is still continuously declining in Britain. An estimated 10,000 plants were present at the site during its best recorded year in 1989, while in 1992 it is believed that fewer than 200 flowering spikes were present (Hurford 1994). At Kenfig, Liparis loeselii occurs in wet dune slacks which are under invasion by Phragmites australis (reed) and Hippophae rhamnoides (sea buckthorn) (Jones 1992, Hurford 1994). Second, Ammophilia arenaria (marram grass) in the foredune areas is declining due to the increase of other biomass. Third, Rumex rupestris (shore dock), and Lomosella subulata (welsh mud wort), both pioneer species, are now almost lost.

Jones (1993) recognised and distinguished 5 principal slack types at Kenfig Burrows. This classification is different from that of Ranwell and Boar (1986) which discriminates between primary slacks (formed at actively prograding sites) and secondary slacks (formed by erosive processes). Jones (1993) comments that the latter category conceals much subtle variation in the dunes and slacks. Consequently his expanded classification identifies 5 slack types as follows:

A	Large complexes (>100,000 m2) oriented west-east and bounded to south and north by elongated dune ridges.
B	Small narrow parabolic slacks (<8000 m2) occurring immediately landward of the haul road.
C	Small parabolic slacks (<13,000 m2) which may be elongated from west-east,although many have no discernable long axis. The characteristic complex of high dunes which generally occur at the eastern end of parabolic slacks may be absent altogether, and type C slacks are generally bound on all sides by dunes up to 20.0 m in height.
D	Slacks less than 5000 m2 in size occurring within dune ridges which are invariably aligned along an east-west axis. These 'ridge slacks' are bounded on all sides by high (5-15 m) dunes.
E	Extremely common type and characterised by a more or less irregular outline with little differentiation into a long and short axis. Usually surrounded by low dunes ( up to 5.0 m above the slack floor).

Jones and Etherington (1992) mention the replacement of the open, herb-rich vegetation by less diverse areas of coarse grassland and thick bushy Salix repens (creeping willow), mainly due to advent of myxomatosis in 1954. The cumulative effect has been the reversal of the geomorphic process of dune mobility and erosion, in other words, dune stabilization. Vegetation changes at Kenfig Burrows have been especially rapid since the cessation of an effective grazing regime during the mid 1970's. Bushy growth forms of Salix repens (creeping willow) now dominate the vegetation of many dune slacks, and there has been a progressive reduction in the number of slacks supporting population of rare and uncommon hydrophytes including Carex serotina, Baldellia ranunculoides (lesser water-plantain) and Anagallis tenella (bog pimpernel).