Ecological consequences of historic moorland ‘improvement’

Abstract

Upland peatlands are nationally and internationally important habitats that can provide a range of ecosystem services, but many are considered degraded by human activities. On Exmoor, (South West England, UK) restoration activities are often aimed at reversing the effects of nineteenth century agricultural ‘improvement’ schemes, the effects of which are not yet fully understood. To develop this understanding, long-term ecological context is essential. We used sub-fossil pollen, plant macrofossils, testate amoebae, insects, coprophilous fungal spores and charcoal to study ecological conditions and disturbance regimes over the last ~ 7700 years at a site in Exmoor National Park (‘Ricksy Ball’). Multivariate analyses were used to explore changes in ecological communities over time and a range of techniques were used to establish the chronology. During the last ~ 7700 years, anthropogenic disturbance regimes (burning, grazing, drainage) have varied through time, reflecting changing land use and management, the effects of which are evident in vegetation (pollen, plant macrofossils) and microbial (testate amoebae) communities. In particular, a combination of drainage and high-intensity grazing appears to have substantially altered local ecology during the nineteenth century, indicated by increases in coprophilous fungal spores and the loss of Sphagnum and associated biota. This occurred in the context of more gradual, centennial-scale declines in Sphagnum and microbial biovolumes. We provide a range of reference conditions and show that the moorland has been influenced by land management changes for millennia, and this may have been most pronounced during the nineteenth century. There is no single, readily identifiable, ‘stable’ pre-drainage baseline. Graphical abstract: [Figure not available: see fulltext.]