Individual study: Butterflies in sprayed and unsprayed field margins
de Snoo G.R., van der Poll R.J. & Bertels J. (1998) Butterflies in sprayed and unsprayed field margins. Zeitschrift Fur Angewandte Entomologie, 122, 157-161
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Leave headlands in fields unsprayed (conservation headlands)
A replicated, controlled, paired study from 1990 to 1992 of arable field edges on 12 farms in the Netherlands (de Snoo et al. 1998) found that unsprayed field margins had greater butterfly (Lepidoptera) abundance than sprayed margins. Butterfly numbers were significantly higher in the unsprayed edges of winter wheat in both years (10-12 butterflies/100 m²) and potatoes in 1992 (5/100 m²) compared to sprayed edges (wheat: 2-3, potato: 1). The same was true for numbers of species: unsprayed winter wheat (3-4 species/100 m²) and potatoes in 1992 (3/100 m²) compared to sprayed edges (wheat: 1-2, potato: 1). In all six individual species, abundance was greater in unsprayed compared to sprayed edges (in one or both years and crops). Strips 6 m x 100 m or 400 m long along field edges were left unsprayed by herbicides and insecticides and were compared to sprayed edges in the same field. Butterflies were sampled once a week on the crop edges and adjacent ditch banks nine times from mid-May to July in 1990 and 1992. This study was part of the same experimental set-up as (de Snoo et al. 1994, de Snoo 1996, de Snoo & de Leeuw 1996, de Snoo 1997, de Snoo 1999).