Calcareous Grassland

The only significant areas of calcareous grassland in West Glamorgan are found on Carboniferous Limestone along the south Glower coast between Mumbles and Rossili. These species-rich grasslands are best developed on the thin, skeletal, rendzina soils that occur close to the cliff edges and on the often steep, rocky south-facing slopes where they form extensive stands of maritime calcareous grassland. It is difficult to describe these habitats without also including the rocky areas and heathy grassland mosaics that are integrated with them. All together, these habitats support a remarkable, diverse flora which includes many rare and notable plant species.

Sheeps Fescue (Festuca ovina) is an abundant component of these grasslands which are otherwise charcaterised by calcicole indicator species such as Crested Hair-grass (Koeleria macrantha), Salad Burnet (Sanguisorba minor), Wild Thyme (Thymus drucei), Carline Thistle (Carlina vulgaris), Common Rock-rose (Helianthemum nummularium), Yellow-wort (Blackstonia perfoliata), Bloody Cranesbill (Geranium sanguineum), Spring Sedge (Carex caryophyllea), Glaucous Sedge (Carex flacca), Squinancywort (Asperula cynanchica) and Small Scabious (Scabiosa columbaria). Of particular note are the spectacular populations of Hoary Rock-rose (Helianthemum oleandicum), a nationally rare species that occurs where limestone rock outcrops along the edges of the cliffs. This species also occurs in western Ireland, but in Britain, apart from Gower, it is only found in Pembrokeshire, North Wales and in a handful of sites in the north of England. Goldilocks Aster (Aster linosyris) is another south Gower rarity which occurs in grassy areas (often amongst Gorse) between Port Eynon and Mewslade Bay. Pale Dog-violet (Viola lactea) occurs in similar places, especially where gorse has been burned. Several other notable species that occur in rocky places in these grasslands are Horseshoe Vetch (Hippocrepis comosa), Spring Cinquefoil (Potentilla verna) and Spiked Speedwell (Veronica spicata), all of which may have been part of a post-glacial steppe-tundra flora now relict on the south Gower cliffs. Two remarkable Mediterranean species also occur along the cliffs, Small Restharrow (Ononis reclinata), nationally very rare with just a handful of coastal sites in western Britain (and often difficult to find) and Nit-grass (Gastridium ventricosum), formerly a more widespread weed of arable land but confined to very few sites in Britain now and at its most western location in Gower.

The low nitrogen, mesotrophic soils of these coastal grasslands support a rich flora of leguminous species such as clovers (Trifolium species). Knotted Clover (Trifolium striatum) and Rough Clover (Trifolium scabrum) are characteristic species, but the more local occurrences of Subterranean Clover (Trifolium subterraneum) and Western Clover (Trifolium occidentale) are particularly worthy of mention. Western Clover was first described from Britain from Cornwall in 1957 and then 30 years later from Tears Point and Mewslade in Gower.

Much of the grassy areas that occur on the deeper soils away from the cliff edges support interesting mosaics of calcicole and calcifuge species merging into a form of maritime heath with Western Gorse (Ulex galii) and Bell Heather (Erica cinera). In the areas between these extremes the grasslands become painted blue in outstanding patches of Spring Squill (Scilla verna) in late Spring and early Summer. Spring Squill is a local species of maritime heath in Britain.

Several Brypophytes are also found in Gower's base-rich grasslands, some of the most notable being Leiocolea turbinata, Dicranum bonjeanii, Encalypta vulgaris, Ephemerum recurvifolium, Microbryum curvicolle, Microbryum rectum, Pottia davalliana, Scleropodium touretii and Weissia longifolia.

Of the numerous grassland fungi found in these habitats, waxcaps are often conspicuous and diverse (e.g.Cuphophyllus colemannianus, C. russocoriaceus).