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The bocage landscape of north-western France has undergone major changes since the middle of the twentieth century, its structure having been altered by land consolidation, the rationalization and enlargement of plots, and the levelling of hedgerows. The environmental consequences of these landscape changes are significant: water erosion, pollution of aquatic environments and loss of biodiversity. The aim of this article is to study the evolution of an agricultural area that is representative of the changes that have affected bocage landscapes over the last two centuries. Using the example of a small, historically bocage watershed in Calvados (Le Tortillon), the methodology is based on a geohistorical approach, combining the use of archives, particularly land registry records, and aerial images within a Geographic Information System (GIS). Although land registers provide precise information on land use in 19th-century landscapes, the article questions the relevance of their representation in terms of landscape structure. The results of two centuries of landscape trajectory show the evolution of land use and bocage structure. In particular, there has been a steady decline in the number of hedgerow lines since the 1940s, in line with the opening up of the landscape, land consolidation and the meteoric increase in the size of agricultural plots. The results of these centuries of change shed new light on the trajectory of a bocage landscape over the last two centuries, and help us to understand the landscape of tomorrow.

Hydrosedimentary fluxes that run from agricultural plots down to the water streams are currently associated with many social, economic and environmental issues such as diffuse pollution, soil infertility, soil loss, floods, etc. While the genesis of these transfers are well-known at the scale of the agricultural plot, flow dynamics occurring on slopes remain poorly understood. This is especially the case in the small basins located in the north-western part of France, where the landscape mosaic, which includes linear networks (hedges, roads, ditches...), tends to complicate the processes. Analyzing the transfer conditions is important for a further integrated watershed management. Hence, in this paper, we propose to use a multi-agent system as a support decision tool to understand the role of anthropogenic linear networks on runoff pathways. We carried out a so-called bottom-up approach, to measure the effects of the local interactions between each linear element on the global hydrological behavior of the watershed. A first spatial analysis index, characterizing the impact of linear networks in the path of runoff, is constructed here from numerical simulations. The results of this study also tend to demonstrate the relevance of Multi-Agent Systems as diagnostic tools to the hydrosedimentary transfers and processes.

Cotton countryside in the Western Burkina Faso has rapidly evolved over the last fifty years. Agrarian and demographic transition has led to an important decline in bush areas. A phase of photo interpretation was conducted on a spatial extent comprising a dozen villages along the protected area of the Tui. After a description of spatial patterns with the help of various indicators (shape, structure ...), a summary of the interactions between the protected area and humanized places is proposed. This study shows that even if this area has been protected for 50 years, rules of access to this area have evolved. The rights for cropping of in the 1950’s and 60’s did not exist, and fields eviction were accelerated in the 1990’s. The agrarian transition coupled with strong desire of protection produce then a recent differentiation of two units, one agricultural and one of nature conservation. On this scale of observation, space competition seems to be important. A second approach based on crop/fallow cycles on a finer scale then distinguishes different spatial and dynamics patterns. This broader scale shows that the large increase in cultivated area does not lead to bush extinction. Some farm units continue the practice of shifting cultivation. Ultimately, this work highlights the importance of the relationship between spatial and temporal scales for studying dynamics in this region.

In the areas with a dairy production and in a hedgerow landscape surrounding, farms appear as the elementary units of the structuration of rural spaces and landscape. The study of the logics of organization of the farmers’ practices thus appears as a pertinent grid to analyze the dynamics of the transformations of agricultural spaces and landscapes. For the dairy farms of the Western Atlantic Europe, the factors linked to the morphology of the fields play a dominating part (plots pulverization, acreage of the farm). From this angle, the analysis of the part played by the distance of the fields from the farm buildings itself as far as the organization of the farmers’ practices is concerned, takes on a central place. How can we take this distance into account and measure it too?The methods coming from the development of the Geographical Information Systems bring along, in this field, interesting advances. Making a grid based on distance criteria to read farmers’ practices highlights the diversity of land use organization of dairy farms in various agricultural and spatial contexts (Galicia, Normandy and England). This diversity then sends back to the dynamics of changes of agricultural systems relating to the land concentration (increase of the farms’ size, land consolidation), relating to the production system (specialization, intensification) and relating to the farms functioning (mechanization, automation, development of cooperative societies).

Classical morphometric indexes have been the first quantitative methods created by geomorphologists to compare the morphometric characteristics of many catchments and to quantify their theoretical hydrologic behavior. Even if many indices still remain quoted in numerous hydrologic books, a few authors have recently underlined the drawbacks of such methods. They are mainly static and not synthetics, and so, they are not sufficient to predict the hydrological response. So, we choose creating relevant indexes basing our approach on new distributed simulation tools as cellular automata (RuiCells) to calculate synthetic indexes based on numerical experiences. Simulations on 422 varied catchments lead a few interesting results. Some efficient spatial configurations are detected at a local scale while at the global scale such behavior was not observed. An index of spatial efficiency is proposed on each cell in order to quantify the efficiency of the network structure in every point within the catchment. The greater values identify the points with the stronger theoretical response.

The level of risk is defined by two standards : uncertainty and vulnerability. The latter is commonly estimated by an overlay of the different information layers, in order to obtain a local quantitative measure of the exposed properties. This approach is convenient for hazardous events clearly delimited and without any spatial diffusion, such as landslides or soil pollution. This approach is however soon bounded in the case of a dynamic process, such as the hydrological hazard. The overlay of different data gives a valuable appreciation of the streaming surfaces, but this remains insufficient to express the spatial dynamics of the flow. The global sensibility of a basin is not merely the sum of the local sensibilities. The global hazard is defined by the spatial organisation of the production or infiltration areas, and by their mutual relations, which validates the cellular automata approach to measure the level of organisation of the sensitive areas and to model the diffusion of the flows between these areas.