Individual study: Improved field margins for a higher biodiversity in agricultural landscapes
Jacot K., Eggenschwiler L., Junge X., Luka H. & Bosshard A. (2007) Improved field margins for a higher biodiversity in agricultural landscapes. Aspects of Applied Biology, 81, 277-283
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Plant nectar flower mixture/wildflower strips
A replicated trial from 2001 to 2005 across nine regions in Switzerland (Jacot et al. 2007) found that wildflower strips sown with a ‘locally adapted’ mix of grass and flower species (species local to the area) had between 10 and 27 target plant species/20 m2, and more butterflies (Lepidoptera), grasshoppers (Orthoptera) and ground beetles (Carabidae) than conventionally cropped margins. The sown ‘locally adapted’ field margins had more butterfly and grasshopper species and individuals than standard wildflower strips, and four to forty times more grasshopper and butterfly species and individuals than conventional cropped margins. There were, on average 3.0 unusual (not ubiquitous) butterfly species and 5.4 unusual grasshopper species in the sown margins. Wildflower strips and ‘locally adapted’ sown field margins consistently had more ground beetle species and individuals than conventional margins. Conventional margins tended to have more spider (Araneae) species (statistically significant only in one region in 2002). The total abundance of spiders and ground beetles was highest in wildflower strips (2,500-4,800 individuals/margin/year/ in total), followed by locally adapted sown margins (2,000-4,000) compared with cropped margins (1,000-2,000). Seventy field margins (5 x 120 m) were sown with seeds of up to 38 grass and wildflower species (‘locally adapted’ mix) in 2001 and 2003. Butterflies and grasshoppers were counted five times between May and August 2003 and 2005 on seven locally adapted sown margins, and compared with standard wildflower strips, conventional cropped margins, extensively managed sown hay meadows and biodiversity-rich meadows. Ground beetles and spiders were sampled using pitfall traps for five weeks from April to July in 2002 and 2004 on four locally adapted sown margins, four standard wildflower margins and four conventional margins. Plants were monitored on all locally adapted sown margins in June 2002-2005.