The environmental history of the preseli region of South-West Wales over the past 12,000 years

Abstract

The project involves a detailed palynological investigation into the environmental changes that took place during the Late-Devensian Lateglacial and Flandrian periods in the Preseli district of northern Pembrokeshire, south-west Wales. The approach adopted specifically takes into account the considerable diversity in terms of subenvironments and ecological habitats within the field area, with representative sites on the northern coastal plain, the exposed ridges of the Preseli Hills, sheltered valleys which dissect the uplands, and the flanking plateaux. In this manner and through definition of local pollen assemblages, unrepresentative extrapolations are minimised and an unbiased regional chronology has been produced. Results indicate that the distinctive climatic character of Pembrokeshire was probably manifest throughout the entire period under discussion. Thus, Corylus was locally present during the Late-Devensian Lateglacial Interstadial as it expanded from refugia to the south and west, and its extension very early during the Flandrian is also recognised. Conversely, Betula was relatively subdued during the Lateglacial and Early Flandrian, therefore suggesting that migration across the Cambrian uplands to the east was inhibited, particularly with the prolonged influences of the Loch Lomond (Younger Dryas) stadial on the high ground. The early establishment of mixed oak forest on the coastal plain is also recognised, although with some variation in its distribution within the field area. Apart from iiilocalised occurrences of carr woodland, however, the main Alnus rise did not occur until c. 6800 BP, when it is suggested that the rising sea-level may have been largely instrumental in creating suitable habitats on the littoral lowlands. During the later part of the period in particular, the variable activities of prehistoric populations are evident. Especially notable is the centre of activity during the Late Neolithic - Early Bronze Age near the site associated with the origins of the Stonehenge Bluestones. During the post-Roman period several cycles of increased exploitation and abandonment are recognised and these correlate well with historical evidence.