Quantifying the extent to which farmers can influence biodiversity on their farms

Our results provide evidence that farmers can indeed positively influence biodiversity by ecological compensation and in-field options. The variables of the ecological compensation set explained the highest proportion in the variation of plant richness and butterfly abundance. We found a significant positive relationship between in-field options and plant abundance. Our study illustrated that the effects of biodiversity-related farming practices differ between species and biodiversity metrics. Conditions outside farmers' control explained a high variation in grasshopper and bird diversity. One variable within the set of farm settings, the degree of consolidation, had a significant negative impact on five out of eight biodiversity metrics (plant, butterfly and bird richness; plant and bird abundance). We demonstrate that farmers can substantially enhance biodiversity on their farms and provide knowledge on how such biodiversity improvements can be achieved by farmers. Further, we highlight the value of new biodiversity-related management practices such as in-field options.