Structure Analysis of Hedgerows with Respect to Perennial Landscape Lines in Two Contrasting French Agricultural Landscapes

International audienceCharacterizing the spatial distribution of hedgerows over landscapes is important for understanding the effects of this distribution on the dynamics of plant and animal populations. Because hedgerows are planted or managed, the authors hypothesized that their distribution depends on the presence of other linear landscape elements, namely, roads and channels. Using proximity analyses, the authors thus assessed how the spatial distribution of hedgerows was impacted by the position of these linear landscape elements and the spatial extent of this impact for two contrasting agricultural landscapes. The results indicate that hedgerows were generally associated at short distances with other elements (100-150 m). Hedgerows had different association patterns depending on their orientation in one of the two landscapes. In that same landscape, within-landscape heterogeneity was related to different association patterns. These results indicate that models of the spatial distribution of hedgerows would gain from being based on the location of roads and channels in the studied landscape

Structures de haies dans un paysage agricole : une étude par chemin de Hilbert adaptatif et chaînes de Markov

National audienceDans cet article nous présentons une approche couplant une courbe remplissant l'espace et une chaîne de Markov pour analyser des données spa-tiales concernant la localisation de haies. Du fait de l'hétérogénéité spatiale des données, nous utilisons une courbe adaptative de Hilbert qui permet de linéariser l'espace en s'ajustant localement à la densité des données. Pour ensuite exploiter la séquence produite, il est nécessaire de caractériser la distance entre un point et son prédecesseur sur la courbe ainsi que la densité locale. Nous proposons de calculer un temps d'accès à un point à partir du point précédent en utilisant la notion de profondeur de découpe. Cette variable, couplée avec les variables caractérisant les haies est ensuite analysée avec un modèle de Markov. Nous présentons et interprétons les résultats obtenus sur un jeu de données d'environ 10000 segments de haies d'une zone de la Basse vallée de la Durance

Structure Analysis of Hedgerows With Respect to Perennial Landscape Lines in Two Contrasting French Agricultural Landscapes

International audienceCharacterizing the spatial distribution of hedgerows over landscapes is important for understanding the effects of this distribution on the dynamics of plant and animal populations. Because hedgerows are planted or managed, the authors hypothesized that their distribution depends on the presence of other linear landscape elements, namely, roads and channels. Using proximity analyses, the authors thus assessed how the spatial distribution of hedgerows was impacted by the position of these linear landscape elements and the spatial extent of this impact for two contrasting agricultural landscapes. The results indicate that hedgerows were generally associated at short distances with other elements (100-150 m). Hedgerows had different association patterns depending on their orientation in one of the two landscapes. In that same landscape, within-landscape heterogeneity was related to different association patterns. These results indicate that models of the spatial distribution of hedgerows would gain from being based on the location of roads and channels in the studied landscape