Recent vegetational changes on blanket mire at Mynydd\ud Llangatwg, South Wales

The Countryside Council for Wales identified that considerable areas of blanket mir~ in South Wales\ud currently support impoverished vegetation as a result of recent anthropogenic influences such as\ud grazing, burning, atmospheric pollution and climate change. One such area is at Mynydd Llangatwg,\ud South Wales, here the blanket mire is now largely dominated by graminoids, particularly Molinia\ud caerulea and Eriophorum vaginatum, and with reduced amounts of ericaceous and Sphagnum\ud species. However, there are few detailed multidisciplinary palaeoecological and palaeoenvironmental\ud studies from South Wales to determining the precise nature and causes of the vegetation degradation.\ud This study aims to firstly, reconstruct a high-resolution vegetational history using plant macrofossil and\ud pollen diagrams from two sites at Mynydd Llangatwg; secondly, to elucidate possible causes of the\ud vegetation degradation using plant macrofossil, pollen, charcoal and peat humification analyses;\ud thirdly, to assign a temporal framework by using spheroidal carbonaceous particle (SCP) analypis.\ud At Mynydd Llangatwg two peat profiles c.1 km apart reveal marked but different vegetational changes.\ud Most notably a rise to dominance of Molinia at profile MLM at a time of around the mid 191\ud h century\ud and the onset of the industrial revolution, and a rise to dominance of Gal/una at MLC sometime before\ud the mid 19th century. Both profiles have also experienced a decline in Sphagnum. The vegetation\ud changes both appear to have come from a vegetation assemblage eo-dominant in Ericaceae and\ud Sphagnum with moderate amounts of Gramineae and Cyperaceae.\ud Examination of the evidence in this study suggests burning, and in particular the frequency of burning\ud may have played a crucial role in the vegetational changes at Mynydd Llangatwg. Grazing may have\ud also been a contributing factor, and grazing and burning may have had combined effects. There is no\ud conclusive evidence for climate change or atmospheric pollution initiating the principal vegetation\ud changes at Mynydd Llangatwg and these would require further examination before firm conclusions of\ud their effects on the vegetation changes could be drawn. A multidisciplinary approach nonetheless\ud limits the potential for misinterpretation of the evidence for past vegetation change and its underlying\ud causes