Structure analysis of hedgerows and other perennial landscape lines in two French agricultural landscapes

Simulating landscape is a main issue for several domains and can be done on the basis of real data or of random spatial patterns. In ecology, these last approaches -also called neutral models, are mainly based on raster approaches. More recently, polygonal approaches have been developed to model vegetation patches or plot fields in agricultural landscapes. In this paper we focus on lines that structure the agricultural landscape, such as roads, irrigation ditches and hedgerows. Our more precise aim is to model hedgerows because of their role for numerous ecological and environmental processes. We investigate ways to characterize hedgerow structures and show results for two contrasting agricultural landscapes, one situated in south-eastern France (grown with orchards) and the second in Brittany (West of France, bocage type). In particular, we assess whether, and under what circumstances, the spatial distribution of hedgerows is structured by the position of more perennial linear landscape elements such as roads and ditches and the scale of such structures. First results show that hedgerow structures were dependent on perennial lines at short distance and that the neighbourhood of hedgerows is uniform beyond 150 meters. Furthermore different structures of neighbourhood were highlighted according to the main orientations of hedgerows in south-eastern France but not in Brittany.