Question: How might contrasting plant groups interact to confer ecosystem stability during the development of a wet heath: i.e. in response to two major environmental drivers, past hydrologic change and burning?

Location: Rannoch Moor, Scotland.

Methods: Three peat cores were used to reconstruct vegetation change, surface moisture and burning phases, during wet heath development for a radiocarbon-dated period from ca. 9500–1000 yr BP.

Results: Statistical analysis of peat cores revealed significant relationships between burning phases and past periods of inferred surface dryness. Vegetation elements were related in the palaeoecological record to surface dryness (Ericaceae), wetness (Sphagnum, monocotyledons, and Racomitrium) and periods of burning (i.e. negative correlation of Racomitrium and monocotyledon remains with charcoal). However, correlations between plant groups could not be adequately explained by their equivalent direct response to hydrology and burning, and the effects of species interactions are invoked.

Conclusions: The results indicate millennial-scale stability of the wet heath ecosystem in response to past environmental change (i.e. hydrology and burning). This stability is conferred by interaction between a diversity of plant groups, enabling local shifts in vegetation composition in response to environmental drivers. This long-term stability of the mire ecosystem forms a template against which present-day threats (e.g. pollution, climate change) should be critically assessed.