Manage forest and woodland to encourage understorey growth
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
The amount of understorey vegetation within forests and woodland has an influence on insect abundance, predation risk and the ability of bats to access the stand interior. Different bat species have been found to prefer different amounts of understorey vegetation, depending on their wing morphology and foraging strategy (e.g. Jung et al 2012).
Jung K., Kaiser S., Böhm S., Nieschulze J. & Kalko E.K.V. (2012) Moving in three dimensions: effects of structural complexity on occurrence and activity of insectivorous bats in managed forest stands. Journal of Applied Ecology, 49, 523–531.
Supporting evidence from individual studies
A site comparison study in 2012–2013 of two forest sites in Brandenburg, Germany (Starik et al. 2018) found that a forest managed to encourage understorey growth had higher overall bat activity and more bat species than a managed forest without understorey growth. Overall bat activity (of 11 bat species), the number of bat species recorded and bat diversity (reported as diversity indices) were higher in the forest with understorey growth (average 1.2 bat passes/hour, 3 bat species/night) than the forest without understorey growth (average 0.3 bat passes/hour, 2 bat species/night). One site (1 ha) was sampled in each of two managed forests, a Scots pine Pinus sylvestris monoculture stand without understorey and a Scots pine stand with pedunculate oak Quercus robur in the understorey. Sites were selected to ensure they were a similar distance to settlements, water bodies and other land use types. At each of two sites, two bat detectors recorded bat activity simultaneously over a total of 37 nights in May–October 2012 and April–October 2013.Study and other actions tested