Tree selection by roosting bats in a European temperate lowland sub-Atlantic forest

Trees are the main roosts for several European bat species but forestry practices are most often detrimental for them. After checking for the presence or absence of bats in trees, we collected a number of variables to describe trees within a lowland sub-Atlantic oak-dominated forest. We modelled the usage of the trees by bats according to the main characteristics of trees (11 quantitative and 13 qualitative variables) with a logistical regression analysis. Our results show that the number of cavities in the tree is the main variable that induces the occupancy by bats. There is a "typical" lowland tree preferred by bats which is a healthy oak tree of large diameter. We finally provide some guidance for woodland managers to maintain bat roosts, including maintaining some trees of large diameter, protecting small areas of old trees with cavities).