Reduce field size (or maintain small fields)
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Reducing field size (or maintaining small fields) means having a greater number of smaller fields, with boundaries and field margins between them. This would provide heterogeneity within the farmed landscape, and may also increase the density of linear habitat features, such as treelines and hedgerows, which are important for commuting, foraging and roosting bats.
Supporting evidence from individual studies
A replicated, site comparison study in 2012 of 46 agricultural sites in Ontario, Canada (Monck-Whipp et al 2018) found that agricultural landscapes with smaller fields had higher activity for six of seven bat species than those with larger fields. Six bat species (hoary bat Lasiurus cinereus, big brown bat Eptesicus fuscus, little brown bat Myotis lucifugus, tricolored bat Perimyotis subflavus, northern myotis Myotis septentrionalis) had higher activity in agricultural landscapes with smaller average field sizes than those with larger average field sizes (data reported as statistical model results). The opposite was true for silver-haired bat Lasionycteris noctivagans which had higher activity in landscapes with larger average field sizes. Forty-six agricultural landscapes (3 x 3 km) with crop fields (including hay, corn, soybean, cereals, legumes, pasture, fallow) of different sizes (number of each not reported) were surveyed during 1–5 nights in May–August 2012. Bat detectors recorded bat activity for 3 h from sunset in two locations along field boundaries within the centre (1 x 1 km) of each landscape.Study and other actions tested