South Gower Cliffs - Gower - page 92

or are heavily grazed by horses and cattle, while at Slade Cliffs part of the common is regularly spread
with manure. Cattle grazing is, however, a traditional form of management on the cliffs at Horton.
It is clear therefore that the cliffs are an unstable mixture of grassland, heathland and scrub that is
maintained by a combination of grazing, burning and a harsh maritime climate. Relaxation of grazing is
unlikely to lead to the succession proceeding beyond coastal scrub, but this would result in the loss of
most of the grasslands except where these are located in an exposed position. It is likely that some com-
munities of the lower cliff, such as the steeply sloping limestone grasslands, could be wholly maintained
by existing physical and chemical factors due to their open and exposed character. Scrub communities on
partsofthecoastaroundOxwichPoint,forexample,mayhavealreadyreachedaclimaxduetotheeffects
of strong winds and salt spray, but there is likely to be scope for considerably more scrub development
especially in areas such as Mewslade.
A recent survey of the area recommended that a comprehensive grazing plan should be developed in
order to conserve the plants and insects of this very rich coastline. It has been difficult for the three con-
servation organisations that jointly own and manage the area, the National Trust, the Wildlife Trust and
the Countryside Council for Wales, to tackle the issue because the situation is complicated by the land
ownership. The most degraded areas are registered common land and are grazed by sheep owned by loc-
al commoners. There was an attempt in the early 1990s to address this issue through a trial reduction in
grazing levels and it was hoped that lower overall stocking rates would provide sufficient herbage for the
sheep,sothattheywouldbelesslikelytograzethevegetationonthecliffs,butsadlytheinitiative didnot
get very far. In 1996, however, the Wildlife Trust bought back the agricultural rights associated with their
property at Overton. Elsewhere in Gower the common rights must be strenuously protected, but given the
seemingly insuperable problems here the removal of rights would, at least, restore the cliffs to their right-
ful glory. A reduction in overall livestock numbers, as a result of the reform of the Common Agricultural
Policy since farmers are no longer being paid subsidies on the basis of the number of animals that they
own, might, however, render this approach unnecessary.
Historically areas of gorse were burnt by the farmers who grazed sheep on the cliffs, as a means of
promotingfresh,palatablegrowthandcontrollingscrubinvasion.Thisburningstilltakesplaceduringthe
winter months, but burns also occur in the dry summer months. Such events control the advance of scrub,
and well-developed scrub communities are found only in situations that are well protected from fire such
as old quarries or areas of scree. A severe burn can destroy the humus-rich topsoil together with all the
microorganisms within it, leaving a sterile subsoil. The bare soil is susceptible to wind erosion, leading to
the exposure of bulb and root systems and ultimately to the exposure of the limestone bedrock beneath.
Where areas of cliff vegetation burn the open exposed ground is colonised by a temporary but typical
community of plants, scarlet pimpernel Anagallis arvensis , which often shows variable flower colours,
cut-leaved crane's-bill Geranium dissectum , Yorkshire-fog, ox-eye daisy Leucanthemum vulgare and
spring cinquefoil. The fire also activates the seeds of the gorse and these species then disappear as the
gorse reinvades the area. A survey of nit-grass carried out in 1985 noted a positive association between
the density of the species and previously burnt gorse stands (John, 1992). Effects on invertebrates are un-
known, but such information as is currently available suggests that the size of the burn is an important
factor regarding speed of recolonisation.
INVERTEBRATES
The mild climate and the wide variety of habitats combine to produce ideal conditions for invertebrates,
andthepeninsula'ssoftcoastalcliffshavebeenknownasakeylocationforbees,waspsandantsformany
years.Morethananyothergroupofinvertebratestheyareunderthreatnationallyduetotheprecisehabit-