Effects of farming management and landscape heterogeneity on plant species composition of Mediterranean field boundaries

The aim of this study was to evaluate the effect of farming management (field and boundary management), boundary structure (width and habitat assemblage), and landscape heterogeneity on plant species composition in field boundaries. Plant species were characterised according to their conservation value, life form and affinity to soil nutrient conditions. We surveyed 30 field boundaries next to organic fields and 30 next to conventional fields distributed along a gradient of landscape complexity. A Detrended Correspondence Analysis was performed using all 517 species recorded in order to study the variation in species composition. Field and boundary management, boundary width, habitat assemblage of field boundaries (estimated with the percentage cover of Mediterranean grasslands) and landscape heterogeneity contributed significantly in predicting the variation in species composition. Perennial species of conservation value with affinity to nutrient-poor soil conditions were more likely to be found in wide managed boundaries characterized by a high percentage cover of Mediterranean grasslands, which are adjacent to organic fields and within heterogeneous landscapes.