Species richness of butterflies greater on organic farms

In this study, we examined whether organic farming affected populations of one group of insects of conservation interest, butterflies, on farmland. The abundance of butterflies on pairs of organically and conventionally managed farms was recorded over 3 years and a number of habitat and crop variables, likely to be related to butterfly abundance, were also measured. Organic farms attracted significantly more butterflies overall than conventional farms. Significantly more butterflies in both farming systems were recorded over the uncropped field margin than the crop edge. The difference in butterfly abundance between crop edge and field margin was relatively greater in conventional than organic systems. Species richness of butterflies tended to be greater on organic farms. Five species of butterfly were significantly more abundant on organic farms in at least 1 year, while no species was significantly more abundant on conventional farms. Increasing the extent of organic farming, or practices associated with it, could help to restore biodiversity in agricultural landscapes.

Source:
R. E. Feber et al. Journal of Zoology, Volume 273, Issue 1, pages 30–39, September 2007
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.2007.00296.x/full