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The landscape patterns are the results of the human activity that adapts the land cover and its use (LUC) to economic and social constraints/opportunities encountered by various actors. The temporal and spatial arrangement of LUC has a strong influence on environmental risks. This paper presents a methodology based on stochastic models to identify, locate and simulate the temporal LUCC of regions differentiated by their successions by means of “neutral” models. The differences between simulated and observed data make it possible to detect breaks in land-use development and planning. We assess our method on data that come from surveys in the Vittel-Contrexéville watershed (East of France) which is subject to water quality issues., L’organisation d’un territoire est le reflet de l’activité humaine qui y adapte la couverture du sol et son usage en fonction des contraintes ou opportunités techniques, économiques et sociétales. L’arrangement temporel et spatial des occupations du sol a une forte influence sur les risques environnementaux. Cet article présente une méthodologie à base de modèles stochastiques pour identifier, localiser et simuler les occupations temporelles des régions différenciées par leurs successions de culture dans la perspective de construction d’un modèle « neutre ». L’écart entre données simulées et observées permet de déceler des ruptures dans le processus de mise en valeur du territoire. Les données utilisées dans cette étude proviennent d’enquêtes effectuées sur l’impluvium de Vittel-Contrexéville concernant la qualité des eaux souterraines.

International audience; Despite hundreds of reports involving both plants and animals, the mechanisms underlying introgression remain obscure, even if some form of selection is frequently invoked. Introgression has repeatedly been reported in species that have recently colonized a new habitat, suggesting that demographic processes should be given more attention for understanding the mechanisms of introgression. Here we show by spatially explicit simulations that massive introgression of neutral genes takes place during the invasion of an occupied territory if interbreeding is not severely prevented between the invading and the local species. We also demonstrate that introgression occurs almost exclusively from the local to the invading species, especially for populations located far away from the source of the invasion, and this irrespective of the relative densities of the two species. This pattern is strongest at markers experiencing reduced gene flow, in keeping with the observation that organelle genes are often preferentially introgressed across species boundaries. A survey of the literature shows that a majority of published empirical studies of introgression during range expansions, in animals and in plants, follow the predictions of our model. Our results imply that speciation genes can be identified by comparing genomes of interfertile native and invading species pairs.