TRE WILMOT SITE OF SPECIAL SCIENTIFIC INTEREST
SITE MANAGEMENT STATEMENT
What is ‘special’ about the wildlife at Tre Wilmot SSSI?
Tre Wilmot SSSI has three very special features:
lowland wet heath comprising areas dominated by heather and cross-leaved heath
marsh gentian, a rare plant occurring in the wet heath
pillwort, a rare aquatic fern.
As well as the features listed above, Tre Wilmot has other habitats that contribute to the special interest. These include rock outcrops, ponds, wetland, grassland and scrub. This mixture of habitats is important for much of the wildlife including three-lobed water-crowfoot, which grows in muddy poached ground. The bog bush cricket and uncommon butterflies such as silver studded blue, grayling and green hairstreak can also be seen here while the rare marsh fritillary butterfly used to occur. Chough can also be seen feeding for insects, grubs and worms on the site.
Unless it is specified below, management of this site should aim to look after these habitats as well as the listed features of interest.
What do we want Tre Wilmot SSSI to look like?
At least two thirds of the site, mostly on the rock ridges will be covered by heathland, dominated by the purple and yellow flowers of the heathers and western gorse respectively. The taller, invasive European gorse should cover less than 10% of the site with only a few scattered patches of bracken and willow trees.
Between the ridges, where the ground becomes wetter, the ground should be dominated by purple moor grass pasture, with cross leaved heath, the yellow star-shaped flowers of the bog asphodel and the white heads of cotton grass. Where water floods the surface there should be black bog rush and the white blooms of grass of Parnassus.
There should be two main areas of open water on the site, containing a variety of plants, including the hair-like leaves of pillwort. Three-lobed water-crowfoot, with its waxy apple green leaves, should grow along sections of the muddy, poached edges of the pools and ditches on the site.
What management is needed on Tre Wilmot SSSI, and why?
Although Tre Wilmot is an excellent site for wildlife, it is not entirely ‘natural’. In fact it is the product of centuries of management. It is essential to continue this management and CCW’s aim is to work with you to achieve this. We place great importance on our relationships with owners and occupiers, because without your help, it will be almost impossible for us to safeguard the special features on your land.
There is some management that is essential to conserve the special features. Other management actions could damage the features within a very short time. These are the ones we regard as the most important
Light grazing, to remove excess herbage, enables the maintenance of dwarf shrub heath and controls the development of scrub. Grazing should be mainly concentrated between May and September. Grazing cattle help to maintain the dwarf shrub heathland within which the marsh gentian grows. Cattle are preferable to sheep, since they are less selective in their grazing habits and therefore allow plants to set seed. No sheep should be used during the gentian flowerings season from July through September. Cattle also help to break up clumps of gorse by trampling and keep edges of pools open; the minor poaching and open paths created by cattle are amongst areas where marsh gentian flowers most freely while poached areas on pool edges are favoured by pillwort and the three lobed water crowfoot. Animal dung is also an important resource for many insects (and fungi) and for the animals that feed upon them such as the chough. Avoidance of Avermectin type veterinary products, especially the long lasting bolus type application, enables this natural breakdown of dung.
This site has traditionally been burnt as a management tool. Burning can rejuvenate heathland and creates opportunities for germination of marsh gentians. However, over-frequent burning impoverishes the invertebrate fauna and encourages gorse and purple moor-grass. It should be used as a tool to encourage correct grazing, not as a primary tool to control the vegetation. No more than a tenth of the heathland area should be burnt annually, following the Grass and Moor Burning Regulations. Fire-breaks should be established. Care should be taken to avoid burning wet heath where mosses could be scorched and killed. To avoid bracken invasion following burning grazing must be maintained, particularly on deeper soils. Controlled burning reduces the risk of large accidental burns, which can devastate large areas of heathland and grassland. Burning on this site needs to be undertaken with extreme caution.
Low soil fertility
No fertilisers of any kind should be applied within the SSSI. Low soil fertility helps heather and western gorse to compete against more aggressive agricultural grasses. The application of any fertiliser or slurry should be avoided and animals should not be fed with silage on the site.
Small patches of scrub should be tolerated on site since they provide shelter and nest sites for a variety of insects, birds and other animals. If burning and grazing are unsuccessful in limiting scrub distribution it may be necessary to cut back European gorse, birch and willow to prevent it encroaching on the heathland areas. Scrub control should be done on a rotational small scale basis followed by grazing and should aim to restore the area of heathland, to control invasive European gorse and to stop wetter areas drying up. Cutting scrub and bruising bracken (or trampling with heavy stock in late spring) is preferable to using chemicals, although stump treatment with chemicals may be the best method of ensuring the roots are killed.
Our knowledge of wildlife at Tre Wilmot is far from complete. It is possible that new issues may arise in the future, whilst other issues may disappear. This statement is written with the best information we have now, but may have to change in the future as our understanding improves. Any information you can provide on the wildlife of your site, it management and its conservation would be much appreciated.
If you would like to discuss any aspect of your SSSI, or have any concerns about your SSSI, please contact your local CCW office.
Cyngor Cefn Gwlad Cymru/Countryside Council for Wales
Llys y Bont,
Ffordd y Parc,
Gwynedd, LL57 4BN,
Fax: 01248 679259