Acid grassland occur throughout the main upland Valleys of RCT, in valley-bottom sheltered pastures, as a major component of the ffridd and as expanses on the upland plateau, wherever thin, acidic ‘Valleys’ soils occur. Classic acid grassland grasses are sheep’s fescue (Festuca ovina), wavy-hair grass (Deschampsia flexuosa), mat grass (Nardus stricta), sweet vernal grass (Anthoxanthum odoratum), velvet and common bent (Agrostis spp) and heath grass (Danthonia decumbens) with green-ribbed sedge (Carex binervis). While herb diversity is naturally less diverse than in more neutral or calcareous grasslands, the flowers are very characteristic and extremely important, and include the white trailing flowers of heath bedstraw (Galium saxatile), the yellow, four ‘petalled’ tormentil (Potentilla erecta), the arrow shaped leaves of sheep’s sorrel (Rumex acetosella), the beautiful heath spotted orchid, bluebells and dog violets (Viola riviniana). In addition, the diminutive, but perfect blue or white flowers of heath milkwort or the equally exquisite blue of ivy-leaved bellflower and thyme leaved speedwell are all frequently found, and devil’s-bit scabious and saw-wort may also occur (Seratula). Using the National Vegetation Classification, the main acid grassland of more sheltered location is ‘sheep’s fescue and common bent’ U4 acid grassland, while ‘wavy-hair grass’ U2 acid grassland can be characteristic of steeper slopes, and ‘mat-grass and heath bedstraw’ U5 acid grassland is a genuinely upland community. Grazed acid grasslands can be particularly important for grassland fungi. 

 

Acid grasslands also support characteristic invertebrate faunas including the tormentil bee, day-flying chimney sweep and forester moths, strongholds of the small heath and small copper butterfly and often landscape of anthills with their attendant invertebrate fauna. Meadow pipit, wheatear and skylark are classic upland acid grassland songbirds, and our remaining cuckoos are dependent on the pipits of the acid grasslands and ffridd. Green woodpeckers are strongly associated with anthill slopes and pastures, and where gorse scrub occurs stonechats and linnets are often present.  

  

Priority Habitats of Wales (edited by P.S.Jones et al, CCW 2003) identifies 1400 ha of lowland acid grassland in Rhondda Cynon Taf (which is 4% off the Welsh habitat resource and of 31% was classed as unimproved).