Manage hedges to benefit bats
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
Background information and definitions
Hedgerows on farms may be subject to various management practices, including cutting. However, there is evidence that bats prefer taller, wider, structurally diverse hedgerows and those with emergent trees (e.g. Boughey et al. 2011, Lacoeuilhe et al. 2016). Reducing the cutting frequency of hedges, planting trees within hedges, retaining and maintaining existing emergent trees, minimising pesticide use and filling gaps within hedges are all likely to benefit bats. For studies that may carry out this intervention alongside other interventions to benefit bats on farmland, see ‘Pay farmers to cover the costs of conservation measures (e.g. agri-environment schemes)’.
Boughey K.L., Lake I.R., Haysom K.A. & Dolman P.M. (2011) Improving the biodiversity benefits of hedgerows: how physical characteristics and the proximity of foraging habitat affect the use of linear features by bats. Biological Conservation, 144, 1790–1798.
Lacoeuilhe A., Machon N., Julien J.-F. & Kerbiriou C. (2016) Effects of hedgerows on bats and bush crickets at different spatial scales. Acta Oecologica, 71, 61–72.
Supporting evidence from individual studies
A replicated, paired sites study in 2008 on 13 pairs of farms in Scotland, UK (Fuentes-Montemayor et al 2011) found that hedges managed for wildlife on agri-environment scheme farms had similar activity of Pipistrellus species as hedges on conventional farms. The activity of common pipistrelles Pipistrellus pipistrellus and soprano pipistrelles Pipistrellus pygmaeus was similar along hedges managed for wildlife and along conventionally managed hedges (data reported as statistical model results). On agri-environment scheme farms, hedges had gaps filled, hedge bottoms were left unmown, and pesticide use and cutting was restricted (cut once every three years). Each of 13 hedges on agri-environment scheme farms were paired with 13 hedges on conventional farms with similar farming activities and surrounding habitats. No details were reported about the management of hedges on conventional farms. Each of 13 paired sites was sampled once on the same night in June–September 2008. Bat activity was recorded along transects (2.5–3.7 km long) from 45 minutes after sunset using bat detectors.Study and other actions tested
A replicated, site comparison study in 2016 on 20 farms in southwest England, UK (Froidevaux et al 2019) found that hedges that had not been trimmed for at least three years had more bat species and greater activity of two of eight bat species/species groups than hedges trimmed during the previous winter. Hedges trimmed ≥3 years prior had more bat species and greater activity of greater horseshoe bats Rhinolophus ferrumequinum and Plecotus spp. than hedges trimmed during the previous winter (data reported as statistical model results). Lesser horseshoe bats Rhinolophus hipposideros were more likely to be recorded along hedges trimmed ≥3 years prior, but activity did not differ significantly. Activity also did not differ significantly for five other bat species/species groups (see original paper for details). There were no significant differences between hedges trimmed two years prior vs. those trimmed during the previous winter. Sixty-four hedges were surveyed on 20 farms (2–4 hedges/farm). Nineteen hedges (under agri-environment scheme management since 2005) had not been trimmed for ≥3 consecutive winters. Twenty-eight hedges were trimmed during the previous winter (four agri-environment scheme, 24 conventionally managed), 17 were trimmed two winters prior (seven agri-environment scheme, 10 conventionally managed). All hedges were mechanically top trimmed. Bats were recorded with a bat detector along each of 64 hedges during one full night in June–August 2016.Study and other actions tested