The Commons of Dartmoor have undergone significant changes in their vegetation over the last twenty years or so, largely as a result of reduced grazing by livestock as required by Natural England (and their predecessor English Nature).
In 2016 the Dartmoor Society commissioned Footprint Ecology to conduct a vegetation survey of Gidleigh Common and part of Chagford Common as a data-gathering exercise to inform us about the state of the commons now. The report, by Sophie Lake, is now available here.