THE NATURE OF THE VEGETATIONAL CHANGES AT ABOUT 5000 b.p. WITH PARTICULAR REFERENCE TO THE ELM DECLINE: FRESH EVIDENCE FROM CONNEMARA, WESTERN IRELAND

Results of palaeoecological investigations on a core from Lough Sheeauns, N.W. Connemara, a small lake sited in an area with a dense concentration of megaliths datable to the Neolithic, are reported. Pollen analysis, involving continuous sampling over a 41 cm interval spanning the elm decline (c. 5000 B.P.), permitted a detailed reconstruction of the vegetational changes and the nature of human impact. The pollen data are supplemented by chemical analysis and a chronology is provided by radiocarbon dating. Farming, including cereal cultivation, in the century prior to the elm decline is demonstrated. The elm decline emerges as a distinct feature in both percentage and concentration pollen diagrams. It is argued that neither an anthropogenic nor a climatic explanation for that event is sustainable in the light of the available evidence; a disease hypothesis is favoured. In the immediate post‐elm decline period, Landnam, involving major woodland clearance in the context of a pastoral‐based Neolithic economy, is recorded as a distinctive feature in the pollen record.