In most European countries, the agricultural landscape has been modified because of intensification of farming practices in order to increase overall productivity. This intensification has reduced the non-cultivated habitats and grazed pastures, which in turn results in reduction of species richness in agricultural landscapes.

In 2005-2006, Swedish researchers analysed how the differences in management practices between small and large farms affect biodiversity. A second goal of the study was to determine whether bird abundance could be used as an indicator of the status of lower trophic level species. A large number of studies show a strong positive effect of organic practices on biodiversity , but this is the first study to assess how diversity is affected by changing farm sizes.

The results suggest that the management practices associated with farm size are an important factor affecting biodiversity. More than twice as many bird species and territories, butterflies, and herbaceous plant species and five times more bumblebees were found on the small farms compared to the large ones. This could be explained by the lack of pesticides, use of crop rotation, and high grazing intensity, most of which are more common on small farms.

When comparing small organic farms with large organic farms, some differences were also noted: 56% more bird species were found on the small farms. The authors argue that this is because the more heterogeneous landscapes with higher crop species diversity on the small farms can harbour more bird, butterflies, and bumblebees species than the more homogeneous landscapes found on the large farms. The largest differences were found between small organic and large conventional farms.

The current study illustrates how important it is to preserve small-scale agricultural areas in order to avoid further decline in bird diversity. The measures taken by current European policy to prevent further loss of biodiversity may not be sufficient since the overall population trend of many farmland bird species across Europe is still negative.

More information available at the DG Environment news alert service “Science for Environment policy”