A spatial approach to upland vegetation change and human impact: the Aber Valley, Snowdonia

Abstract

Uplands have long been considered important ‘barometers’ for human-environment relationships. Five pollen sequences from the upper Aber Valley (Snowdonia), across an altitudinal gradient, reveal that human impacts have varied temporally on small spatial scales in the region. Woodland taxa persisted into the later Holocene at lower altitudes and sites located at higher altitude reveal a more open landscape history, possibly as a result of increased exposure limiting tree growth at high elevation. Continuous pastoral human land use is evident in the high upland (400 to >600 m AOD) landscape with evidence of clearing, burning and grazing indicators throughout the records covering the last ∼6000 years, with increased activity apparent during the last 2000 years. There is no clear evidence to suggest that climate change (e.g. deteriorating climatic conditions from ∼850 BC) resulted in land abandonment and it appears more likely that climatic shifts could have led to changes in human land management. The results demonstrate that pastoral land use varied at different altitudes across the Aber Valley upland, and have highlighted the value and potential of high/fine spatial sampling in providing insights into land use history and the mosaic of habitats that result.

Keywords:

• Snowdonia
• pollen
• vegetation
• Holocene
• spatial sampling
• uplands

This research was financially supported through the University of Plymouth Geography Research Pump Priming Fund, and Snowdonia National Park Authority (who provided funding for radiocarbon support). The work emerged out of discussions with John Roberts and Bob Johnston, and their encouragement and enthusiasm was warmly welcomed. Katie Head provided invaluable assistance in the field. The authors would also like to thank two referees for making suggestions that significantly improved an earlier version of this manuscript.