The distribution of mountain hares and the possible effects of woodland expansion using the Cairngorm National Park as a case study

Woodland expansion is widely promoted to address the effects of climate change and biodiversity loss. Woodland expansion undoubtedly delivers biodiversity and other ecosystem service benefits, but there is debate about where to place extensive new woodland in multi-use landscapes without negatively affecting existing biodiversity, and there is a need to better understand the biodiversity trade-offs associated with woodland expansion. Using the Cairngorm National Park (CNP) in northeast Scotland as a case study, we assessed how proposed woodland expansion targets might affect the distribution of mountain hares, an open moorland species strongly associated with moorland management. Using mountain hare survey, bioclimatic and land use data, we built a Species Distribution Model of mountain hares within the CNP and used this to predict their occurrence under current and proposed woodland expansion scenarios. Simulating the effects of an additional 70 and 350 km² of new woodland cover showed that combined, these targets would see hares lost from 246 1-km squares, a 7% reduction in their occurrence compared to their 2006/2007 distribution. Changes in hare occurrence were driven by changes in management associated with landcover change more than by landcover change itself. Our results show that afforestation can negatively affect species occurrence directly through changes in landcover, and indirectly through changes in management associated with land landcover change.