Long-term habitat use and browsing by deer in a Caledonian pinewood

Abstract

The incidence of browsing to Scots pine ( Pinus sylvestris) saplings by red deer ( Cervus elaphus) and roe deer ( Capreolus capreolus) in Caledonian pinewoods has been shown to be correlated to faecal counts. However, on a seasonal basis, the relationships are weak and vary between habitats, and are therefore of low predictive power. This may in part be because faecal counts provide an index of habitat use integrated over many months, whereas browsing events are of much shorter duration. To examine the relationships between habitat use by deer and browsing further, we use 10 years’ dung counts from a Scottish estate to identify which habitats are used most heavily by deer, whether their preferences remain consistent over time and whether local browsing impact is more closely related to faecal deposition when integrated over a period of many years. Spring dung counts along permanent transects were modelled against a range of explanatory variables including habitat type. Indices of long-term browsing pressure were derived from measurements of pine saplings, but showed no clear relationship to habitat use. The two deer species showed broadly similar patterns in relation to habitat and location, but they differed in terms of which habitats showed the strongest changes in use as population levels changed. Model residuals were spatially aggregated and inter-correlated, suggesting that both species responded similarly to unrecorded factors influencing their winter distribution, such as disturbance, use of neighbouring habitats or local variation in forage quality.