The impact of forest stand structure on red squirrel habitat use

The native Eurasian red squirrel is considered endangered in the UK and under strict legal protection. Long-term habitat management is a key goal of the UK conservation strategy. Current selection criteria of reserves and subsequent management mainly consider species composition and food availability. However, there exists a critical gap in understanding and quantifying the relationship between squirrel abundance, their habitat use and forest structural factors. This is partly a result of limited availability of structural data along with cost-efficient data collection methods. We investigated the relationship between structural characteristics and squirrel feeding activity in Scots pine. Field data were collected from two study areas: Abernethy and Aberfoyle Forest. Canopy closure, diameter at breast height, tree height and number of trees were measured in 56 plots. Abundance of squirrel feeding signs was used as an index of habitat use. We used a generalized linear model to model the response of cones stripped by squirrel in relation to field-collected structural variables. Results show that forest structural characteristics are significant predictors of feeding sign presence; canopy closure and number of trees contribute to explain 43 per cent of the variation in stripped cones. Our findings critically highlight the need to consider stand structure in management for red squirrels.