Removal of woody vegetation from uncultivated field margins is insufficient to promote non-woody vascular plant diversity

Summary, in English

Uncultivated field margins are one of the most frequent non-crop habitat types in contemporary, highintensity

agricultural landscapes and may therefore be important for the persistence of many farmland

species. Managing field margins in a way that preserves, and preferably enhances, their value for

biodiversity is therefore important. In the present study, we evaluate how the flora of uncultivated field

margins is affected by the removal of woody vegetation as prescribed by an agri-environment scheme

(AES) under the Swedish Rural Development Program 2007–2013. We used generalized linear mixed

models and detrended correspondence analysis to compare the flora of open (cleared) and more

overgrown field margins, located within agricultural landscapes of different complexity, in Scania, S.

Sweden. As expected, there was a negative effect of management on woody species. However, the local

(1m2) and transect (100 m) level richness of non-woody species did not differ significantly between

management categories, and there were no differences in the within-transect variability of non-woody

species (local b diversity) or the species composition (0.25m2 plots) in managed and unmanaged field

margins. Our results show that the removal of woody vegetation from uncultivated field margins, as

prescribed by the evaluated AES, is unlikely to benefit non-woody plant species. The species composition

of the sampled field margins suggests that inclusion of appropriate field layer management alone is

unlikely to be sufficient to improve habitat conditions for grassland species unless measures are taken to

counteract eutrophication. Landscape type, on the other hand, influenced both the total richness and the

richness of each of the species groups that were considered to be of particular conservation value in the

present study: field margins in the complex agricultural landscapes were significantly richer than those

in the simple ones. Maintaining non-crop habitat at the landscape scale is likely to be a necessary first

step in the prevention of a further decline of farmland plants.