Rewilding as a Mechanism for Natural Flood Management in Upland Peaty Catchments in the Lake District

ABSTRACT Rewilding is an emerging conservation methodology that aims to reinvigorate natural processes to form self‐sustaining ecosystems. There are close links between the aims of rewilding and natural flood management (NFM), yet the potential of rewilding to provide opportunities for mitigation of hydrological extremes alongside improving biodiversity and carbon storage is under‐researched. Two catchments in the Lake District are compared to investigate and evidence the potential of rewilding to increase the water holding capacity of peaty upland landscapes. These are ‘Wild Ennerdale’, one of the longest running rewilding projects in the United Kingdom, and Thirlmere, which is more traditionally and intensively managed by a large private water company and its tenants. Field observations, collected during summer 2023, indicate that upland vegetation communities at Ennerdale exhibited significantly greater vegetation height and dwarf shrub cover, as well as reduced soil compaction, compared to Thirlmere. These differences were largely attributed to lower grazing intensity at Ennerdale. Both vegetation height and percentage cover of dwarf shrubs were shown to be strongly negatively correlated with compaction. More developed and woody vegetation communities increase the hydrological function of the uplands by increasing surface roughness, interception, evapotranspiration and infiltration, as well as providing better quality habitats to support biodiversity. The results show the importance of joint consideration of ecology and hydrology to evidence the value of rewilding, as traditional indexes such as species richness do not capture ecological function, and some measures of soil characteristics may take longer than 20 years of rewilding to produce a detectable signal.