The use of phytosociological data in conservation assessment: a case study of lowland grasslands in mid Wales

Quantified vegetation data from remnant stands of neutral and acidic dry grasslands and wet pastures in lowland Brecknock, mid Wales, are presented. Following a preliminary and comprehensive habitat inventory, detailed plant community survey was carried out at a total of 114 sites, and the survey results were used as a basis for nature conservation assessment. A systematic site selection procedure is followed, based on that used to select Sites of Special Scientific Interest, to identify priority sites for conservation. Critical analysis and evaluation based largely on fine-scale phytosociological data are undertaken to identify a representative network of grasslands meriting priority conservation attention. Sites are assessed for individual vegetation types, grassland mosaics and uncommon plant species; size, naturalness and rarity are the main attributes employed for comparative site evaluation. Unimproved grasslands have become much reduced since the 1930s, and particular consideration is given to uncommon communities, including Centaureo–Cynosuretum and Cirsio–Molinietum, and associated populations of scarce and declining species. Overall, 31 sites are considered to warrant priority conservation measures. The exiguous extent and isolation of some forms of lowland grassland point to the need for urgent protection and also habitat restoration and expansion. The benefits of tailoring agricultural extensification measures to reflect local environmental variation, and of localising resources for habitat reconstruction in the vicinity of remnant aggregations of unimproved grasslands, are briefly considered.