Farmland heterogeneity & complementation a case study on carabid beetles

Since the recognition of the importance of biodiversity for agro-ecosystem functioning and ecosystem services, maintaining biodiversity in agricultural areas has been a major issue. Landscape heterogeneity is a key factor for sustaining and restoring biodiversity. Most studies dealing with landscape effects on biodiversity in agricultural landscapes focused on semi-natural elements. But, many arthropods species are not limited to these habitats and often require cultivated elements (complementation), which results in ‘spill-overs’ from semi-natural to cultivated habitats. Recent studies also suggested that spatio-temporal complementation processes can occur between crops sown at different periods (winter vs. spring), that offer asynchronous shelter and resources for species. We hypothesised that winter crops are appropriate habitats in spring while spring crops are in autumn, which make them complementary over time. Because these aspect involved population dynamics at landscape scale, we tested the effects of farmland composition and spatial organisation on carabid beetles communities of crop habitats