Caves and Swallets - Gower - page 290

ofacomplexbacteriumontheborderlinebetweenbacteriaandfungi,aspeciesof Streptomyces ,probably
associated with a fungus, Fusarium spp.
NEW DISCOVERIES
Passages largeenoughtoadmit people,'macrocaverns', formonlyatinyproportionofthetotal cavehab-
itat, the great majority being 'mesocaverns', that is holes with a diameter ranging from 1 to 200 milli-
metres. It has been estimated that the habitable surface area within limestone mesocaverns 'must run to at
leasttwoorthreeordersofmagnitudemorethanthatwithinexploredcaves'(Chapman,1993).Itiswithin
these mesocaverns, which are for the most part completely inaccessible to the naturalist, that the majority
of the specialised flora and fauna of the Gower caves resides, but to date there have been no studies of
this habitat. The communities remain mysterious and under-recorded. However, judging by the studies of
other cave habitats in Britain, it is likely that a wide range of species are present in the mesocaverns ran-
ging from bacteria and fungi to flatworms, mites, polychaete worms and spiders. Important discoveries
arealsolikelytobemadeinrelationtomicrocrustaceasuchascopepodsandcladocera.Thestudyofcave
ecosystems is still at an early stage and it is not unlikely that new species await discovery in the subter-
ranean habitats of Gower.
CAVE MANAGEMENT
As with the wildlife of the Gower caves, there is also still surprisingly little information available on the
factors that affect both the limestone caves and their wider surroundings, the so-called 'geoecosystem'.
Such cave geoecosystems comprise the cave itself, the surrounding and interconnected system of smaller
openings and the overlying soils and land surface. The three commonest activities which affect these sys-
tems are recreational activity, mineral extraction and agriculture. The most significant of these, certainly
in Gower, are agriculture and recreation. Agriculture impacts on cave geoecosystems largely through its
effectontherunoffthatentersthearea,althoughtherootsofcertainagriculturalcropsareknowntoweak-
en cave roofs, leading to 'blockfalls'. A change of vegetation cover from grazing pasture to arable land
can also have a significant effect, as can pollutants such as organic chemicals, nitrate fertilisers and anim-
al sewage. Cave systems receive inputs of water both from rainfall over the limestone area and from rain
that falls onto adjacent non-limestone areas but feeds streams which run onto the limestone. Increased
sedimentation following ground surface disturbance in cave catchments can result in the loss of inver-
tebrate breeding sites. Indirect influences paradoxically probably have the most extensive impact and by
their nature are the hardest to identify.
In Britain this 'whole catchment' approach to cave conservation has been extremely difficult to apply
asthereareproblemsinextendingconservationmeasurestolandwhichisnotinherentlyvaluableforcon-
servation. Even quite small caves can have extremely large catchments, and though some activities may
appeartohavearelativelyminorimpactintheshortterm,considerationneedstobegiventothecumulat-
ive impact over a longer period. In Gower it would be possible to modify the management prescriptions
for those farms in agri-environment schemes that form part of cave catchments, but further research is
needed, first to classify individual features of interest within the Gower caves and then to map their loca-
tions both within the caves and in relation to the surface.
There are noaccurate figures forthenumber ofcavers usingthe Gowercaves each year,butgiven the
profile of the peninsula in caving circles the total must be very high (Fig. 164). Some caves have been
gridded to prevent access, particularly caves such as Cathole and Tooth Cave, which both provide winter