LONG-TERM VEGETATION RECOVERY AFTER VEHICLE TRACK ABANDONMENT ON DARTMOOR, SW ENGLAND, UK

The use of extensive track networks on northern Dartmoor has caused considerable damage to vegetation during the past 24 years. The number and use of tracks has increased over this period. This paper describes the natural recovery of vegetation on tracks abandoned at several times in the past on five different sites. The undamaged vegetation varies from Agrostis grassland to wet moorland dominated by Calluna vulgaris and/or Molinia caerulea. Analysis of environmental parameters shows that the most recently used tracks suffer compaction and reduced soil depth and moisture. Canonical Correspondence Analysis (CCA) is used to explore these effects further, and the way in which vegetation can be expected to change over time is deduced from comparison of tracks of different ''ages'' as a ''time-track'' on an ordination diagram. Recovery may be rapid in grassland and heathland sites but areas of higher moorland and blanket bog recover more slowly and may never revert to their original vegetation composition. The results are discussed with respect to practical conservation management of the area. (C) 1995 Academic Press Limited