Landscape scenarios to evaluate the impact of organic farming on selected animal species

Summary

A total of seven scenarios were constructed to model different aspects on the influence of organic farming practice in the Herning model area. The chosen scenarios aimed to describe different levels of organic farms present and different levels of crop management intensification on organic farms (mechanical weeding, density of live stock grazing, watering). Extensified conditions were a reduction of 50% in intensity compared to standard conditions. The effects of the scenarios were tested on: carabid beetle (Agonum dorsale), Linyphiid spider (Erigone sp.) and skylark as these species are expected to be the most sensitive species in relation to impacts following the agricultural changes described above.
Following main results were obtained:
• Organic scenarios indicated that organic farming was beneficial for all species considered. However, the impact varied depending upon the crops grown.
• The impact of the current organic farms on the landscape at large was measurable, but not large
• 100% organic farming led to a 9-120% increase in numbers depending on species.
• Extensification of management had clear beneficial impacts on spiders and skylarks, but not beetles.
• The ‘nature’ rotation (‘nature optimised’) was better for skylarks, but inferior to the standard rotations for beetles and spiders.