One of the best-set-up reserves in this list — proper trails, a hide, and a genuinely excellent chance of reptiles if you're patient — but it's exactly this kind of sensitive heath where dogs need to stay close and on a short lead, adders included. Like much of the Purbeck heaths, tracks can close in dry spells if wildfire risk spikes — Wareham Forest itself lost over 220 hectares to fire in 2020, so it pays to check before a summer visit.
A Dorset Wildlife Trust reserve four miles east of Wareham, internationally important for its mix of dry and wet lowland heath and woodland within a SSSI. It's home to all six native British reptiles, including the rare smooth snake and sand lizard, plus silver-studded blue butterflies and Dartford warblers. Self-guided trails lead from the car park, with a bird hide overlooking the pond reached by a level, wheelchair-accessible track.