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Providing evidence to improve practice

Individual study: Importance of ecological compensation areas for small mammals in intensively farmed areas

Published source details

Aschwanden J., Holzgang O. & Jenni L. (2007) Importance of ecological compensation areas for small mammals in intensively farmed areas. Wildlife Biology, 13, 150-158


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Establish wild flower areas on farmland Terrestrial Mammal Conservation

A replicated, site comparison study in 2003 on a farmed plain in Switzerland (Aschwanden et al. 2007) found that sown wildflower strips contained more small mammals than did conventionally farmed grasslands, autumn-sown wheat fields and uncultivated herbaceous field margins. These comparisons were not tested for statistical significance. Small mammal densities varied greatly between sampling periods but peak densities were estimated at 1,047/ha in wildflower strips, 86/ha in farmed grasslands, 568/ha in wheat crops and 836/ha in herbaceous strips. Two small mammal species were caught in wildflower strips, with two each also in grassland and wheat and six in herbaceous margins. Wildflower strips (15 × 185 m) were sown with native species on fallow arable land. Grasslands (average 0.88 ha) were cut ≥5 times, each April–October and were fertilized. Autumn-sown wheat fields (average 1.3 ha) were harvested at the end of July. Herbaceous strips (5 × 320 m) comprised a range of herbaceous plant species along field margins. Small mammals were live-trapped on three fields of each treatment during 60-hour trapping sessions in March, May and July 2003. Densities were estimated using a capture-recapture method.

(Summarised by Nick Littlewood)

Create uncultivated margins around intensive arable or pasture fields Terrestrial Mammal Conservation

A replicated, site comparison study in 2003 on a farmed plain in Switzerland (Aschwanden et al. 2007) found that uncultivated herbaceous field margins contained more small mammals than did conventionally farmed grasslands and autumn-sown wheat fields, though fewer than did sown wildflower strips. These comparisons were not tested for statistical significance. Small mammal densities varied greatly between sampling periods but, at their peak, were estimated at 836/ha in herbaceous margins, 86/ha in farmed grasslands, 568/ha in wheat crops and 1047/ha in wildflower strips. Six small mammal species were caught in herbaceous margins compared to two in each of the other treatments. Herbaceous field margins (5 × 320 m) mainly comprised thistles Cirsium spp., common teasel Dipsacus sylvestris, St John’s wort Hypericum perforatum, common mallow Malva sylvestris and mulleins Verbascum spp. Grasslands (average 0.88 ha) were cut ≥5 times each April–October and were fertilized. Autumn-sown wheat fields (average 1.3 ha) were harvested at the end of July. Wildflower strips (15 × 185 m) were sown with native species. Small mammals were live-trapped on three fields of each treatment during 60-hour trapping sessions in March, May and July 2003. Densities were estimated using a capture-recapture method.

(Summarised by Nick Littlewood)

Create uncultivated margins around intensive arable or pasture fields Farmland Conservation

A replicated, controlled study in the summer of 2003 in central Switzerland (Aschwanden et al. 2007) found that small mammal density was higher in herbaceous strips than in low-intensity meadows, conventionally farmed artificial grasslands and autumn-sown wheat fields. Small mammal species richness in herbaceous strips (six species) was higher than in any other studied habitat (two species each). The increase in small mammal density over the summer was higher in herbaceous strips and wild-flower strips than in the other three habitats. Herbaceous strips consisted mainly of herbaceous plants, such as thistles Cirsium spp., common teasel Dipsacus sylvestris, St John’s wort Hypericum perforatum, common mallow Malva sylvestris and mulleins Verbascum spp. On the 15 study sites, herbaceous strips and wild-flower strips were not regularly cut during the growing season, whereas other grassland habitats were cut at least twice. Small mammals were trapped and individually marked during 60 hour trapping sessions in March, May and July. Traps were checked every eight hours. A capture-recapture method was used to estimate small mammal densities.

Plant nectar flower mixture/wildflower strips Farmland Conservation

A replicated, controlled study in the summer of 2003 in central Switzerland (Aschwanden et al. 2007) found higher densities of small mammals (mainly common voles Microtus arvalis) in wildflower strips than in low-intensity meadows, conventionally farmed artificial grasslands and autumn-sown wheat fields. Small mammal species richness in wildflower strips was equal to that in conventionally farmed habitats and low-intensity meadows, but lower than in herbaceous strips. Over the summer, small mammal density increased most in the wildflower strips and herbaceous strips than in low-intensity meadows, conventionally farmed artificial grassland and autumn-sown wheat fields. Wildflower strips (fallows sown with seed mixtures of native plants) and herbaceous strips (consisting mainly of herbaceous plants such as thistles Cirsium spp., common teasel Dipsacus sylvestris, St John’s wort Hypericum perforatum, common mallow Malva sylvestris and mulleins Verbascum spp.) were not cut regularly during the growing season, whereas the other grassland habitats were cut at least twice. A capture-recapture method was used to estimate small mammal densities. Small mammals were trapped and individually marked during 60 hour trapping sessions in March, May and July.