Reduce field size (or maintain small fields)

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

60%
Certainty

30%
Harms

0%

Calculating overall effectiveness category

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.

Study locations

Key messages

One study evaluated the effects of maintaining small fields on bat populations. The study was in Canada .

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Abundance (1 study): One replicated, site comparison study in Canadafound that agricultural landscapes with smaller fields had higher activity (relative abundance) of six of seven bat species than landscapes with larger fields.

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

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
Referenced paper
Monck-Whipp L., Martin A.E., Francis C.M. & Fahrig L. (2018) Farmland heterogeneity benefits bats in agricultural landscapes. Agriculture, Ecosystems & Environment, 253, 131-139.

Please cite as:

Berthinussen, A., Richardson O.C. and Altringham J.D. (2021) Bat Conservation: Global Evidence for the Effects of Interventions. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Bat Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Provide or retain set-aside areas in farmland Action Link	No evidence found (no assessment)	0	Synopsis Link
Pay farmers to cover the costs of conservation measures (e.g. agri-environment schemes) Action Link	Unlikely to be beneficial	3	Synopsis Link
Reduce field size (or maintain small fields) Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link