Yves Bas, Doctoral Candidate
French National Museum of Natural History, Paris, France

Forestry Lecture Theatre, Forestry Building, Linnaeus Way, ANU
Thursday 24 July, 2008 13:00

Biodiversity loss due to agricultural intensification is a major conservation problem in Western Europe and is causing apprehension in eastern part of the continent. Large-scale studies have shown that national trends of farmland species are negatively correlated to national intensification indicators, but a lack of coherence with national-scale studies make difficult to conclude on specific cause of declines. Here we propose a study using finer scale agricultural data in a large country with diverse landscapes showing a broad gradient of intensification. We modelled local abundance of 43 farmland bird species with the French BBS data. For this purpose, we used a set of control variables including local climate and habitat types, and an indicator of production intensity based on standardised crop yields and pasture stocking rates. For both cropping and pasture systems, our results showed a negative link between response of species to production intensity and their 1970-2000 trends in Western Europe. We also analysed relations between these responses and a large panel of life history traits known to affect bird dynamics. This led to the observation that the distinction between ground-nesters and bush- or tree-nesters is best explaining variation of responses among farmland species, ground-nesters exhibiting a much higher sensitivity to intensification gradient. This relation remains robust when other traits are associated. We argue that our results are of major conservation concern not only because production intensity seems to be the driver of many species declines but also because ground-nesters should be the targets of extensification measures.