Vegetation patchiness of field boundaries in the Mediterranean region: the effect of farming management and the surrounding landscape analysed at multiple spatial scales.

摘要

The purpose of the current work was to study vegetation patchiness of field boundaries within Mediterranean agricultural systems by analysing the effect of the management of field boundaries and their adjacent fields (organic vs. conventional fields), as well as the surrounding landscape evaluated at multiple spatial scales. Different habitat types were identified along 30 field boundaries next to organic fields and 30 boundaries next to conventional fields following the List of Catalonia CORINE Habitats. Vegetation patchiness of field boundaries was estimated by means of habitat richness, the Shannon habitat diversity index, and the percentage cover of ruderal vegetation, Mediterranean grasslands, and woody vegetation. In order to evaluate the surrounding landscape at multiple scales, circular sectors of different extent sizes (150, 300, 1000 m radius) were centred on each field, and two grain size maps (100 m2 and 22,500 m2 minimum patch size) were used. Fourteen landscape metrics for each scale were computed, and they were summarized using a Principal Component Analysis (PCA). Although landscape metrics changed when altering the scale (grain size or extent), the first component of the PCA for all scales described a gradient in 'agricultural intensification', and the second component for all scales described a gradient in 'anthropogenic intensification'. Boundary and field management had no influence on vegetation patchiness of field boundaries. Moreover, field boundaries were patchier in landscapes with a high proportion of natural habitats.Digital Object Identifier http://dx.doi.org/10.1016/j.landurbplan.2012.02.005