Black Mountain

This is an important upland site of special interest for its vegetation, open water and birdlife. It forms an interesting comparison with Brecon Beacons SSSI to the east in having a more varied geology. In addition to the Old Red Sandstone there are significant outcrops of Carboniferous Limestone and Millstone Grit.
The summit ridges are notable for their extensive grassland, dominated in the main by mat-grass Nardus stricta, frequently seen developing on mineral soil exposed by the total erosion of the once widespread blanket bog peat. Heavy grazing, burning and the possible past and present effects of soot and sulphur dioxide pollution are believed to have caused the decline of blanket bog vegetation and dwarf-shrub heath here and elsewhere. However, small areas (notably Drysgol) still support heather Calluna vulgaris and bilberry Vaccinium myrtillus.
The north and east facing cliffs of Bannau Sir Gaer and Bannau Brycheiniog support an interesting arctic-alpine flora, with such species as northern bedstraw Galium boreale, dwarf willow Salix herbacea, lesser meadow-rue Thalictrum minus and roseroot Sedum rosea, together with a rich moss and liverwort flora.
Nutrient-rich flushes are frequent throughout the site, with herb, sedge and moss-rich examples. Limestone grassland and low limestone pavement support lime-loving plants such as limestone bedstraw Galium sterneri, limestone fern Gymnocarpium robertianum and common rock-rose Helianthemum nummularium.Of the several mountain lakes present, Llyn y Fan Fach is of special note as one of the most southerly examples of a corried lake in Britain. It has the uncommon quillwort Isoetes lacustris growing on its sandy bed, and also there is a diverse benthic insect fauna which includes five species of stonefly.
The northern cliffs support an important population of ring ouzels and the site is hunted over by raptors, particularly in winter by the red kite.

Carmarthenshire Bird Watching