Long-term trends in restored moorland vegetation assemblages

Abstract

Restoration of moors dominated by Calluna vulgaris is carried out for conservation and sporting reasons. Previous research has shown variable restoration success in the early years of restoration management. In this study we investigated whether restored heather moorland vegetation increasingly resembles long-established moorland vegetation over a longer time period. Vegetation at seven moorland restoration sites (six in northern England and one in Scotland) was sampled in 2003 (to assess short-term restoration success) and 2010 (to assess long-term restoration success). Three of these sites were restored solely by grazing control and four by a suite of more intensive techniques. On each visit, vegetation sampling was carried out in degraded, restored and long-established control areas at each site. Restored vegetation assemblages closely resembled control assemblages. The samples were, though, dominated by the species targeted for management, Molinia caerulea and Nardus stricta in degraded samples and Calluna vulgaris in control samples. Discounting these species and concentrating on the remainder of the vegetation assemblage, areas restored solely by the reduction or removal or sheep grazing more closely resembled control assemblages whilst those managed more intensively were more intermediate between degraded and control assemblages. There was no systematic pattern of change in restored areas between the sampling dates. At two sites restored samples become more similar to control samples whilst restored samples at other sites either showed little change or moved back towards a degraded assemblage. Thus whilst moorland restoration can succeed in re-establishing C. vulgaris, we found no evidence of a systematic shift in the remainder of the vegetation assemblage towards that of a long-established moor over the time period studied.