Individual study: Agri-environment schemes and foraging of barn owls Tyto alba
Askew N.P., Searle J.B. & Moore N.P. (2007) Agri-environment schemes and foraging of barn owls Tyto alba. Agriculture, Ecosystems & Environment, 118, 109-114
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Plant grass buffer strips/margins around arable or pasture fields
A replicated study in 2003 and 2004 in England, UK (Askew et al. 2007) found that sown grass field margins tended to have higher numbers of small mammals than set-aside. Numbers of captured small mammals were highest in 2 m margins (2.9-4.4 individuals), followed by 6 m margins (2.5-3.6) and set-aside (1.6-2.0). Numbers of small mammals captured were correlated with sward height in 2 m margins. In 2003, significantly more common shrews Sorex arenaeus were captured in 2 m margins (1.4 individuals) than set-aside (0.6) and more wood mice Apodemus sylvaticus were found in 6 m margins (1.1) than set-aside (0.5). The trend was similar for bank voles Clethrionomys glareolus in 2004: 6 m margins (1.6), 2 m margins (1.4) and set-aside (0.5). Species richness did not differ significantly (1.7-2.0). Species richness, total number of small mammals captured, and the number of bank voles and common shrews captured was higher in 6 m margins cut every 2-3 years compared to those cut annually, although this was only significant for common shrews in 2003. Following establishment, 2 m margins were cut at 2-3 year intervals. For 6 m margins, eight 2 m strips at the edges of margins were cut annually and 12 were cut every 2-3 years. Twelve small mammal traps were set within 20 plots per treatment (1 m from the habitat boundary) for four days in November-December 2003-2004. Mammals were individually fur-clipped and released.
Provide or retain set-aside areas in farmland
A replicated site comparison study of agri-environment scheme habitats in arable farmland in England (Askew et al. 2007) found that set-aside tended to have lower numbers of small mammals than sown grass margins. Numbers of small mammals caught in permanent set-aside (fallowed for five years or more, annual cutting of at least 90%: 1.6-2.0 mammals/plot) were lower than in 2 m grass field margins (2.9-4.4 mammals/plot) and 6 m margins (2.5-3.6 mammals/plot). In 2003, significantly fewer common shrew Sorex araneus and wood mouse Apodemus sylvaticus were captured in set-aside (shrews: 0.6; mice: 0.5) than grass margins (shrews: 0.9-1.4; mice: 0.7-1.1). The trend was similar for bank voles Myodes glareolus in 2004 (set-aside: 0.5 voles/plot; margins: 1.4-1.6 voles/plot). Species richness did not differ significantly between treatments (1.7-2.0 species). Twelve small mammal traps were set within 20 plots per treatment (1 m from the habitat boundary) for four days in November-December 2003-2004. Mammals were individually fur-clipped and released. Results from farm woodlands are not included here.