Variation of farm spatial land use pattern according to the structure of the hedgerow network (bocage) landscape: a case study in northeast Britany

The spatial pattern of fields and associated land use types in farms contributes to the landscape and its associated ecological dynamics. This pattern is also a component of farm management and development. This paper deals with modeling the land use spatial organization in farms according to these dual criteria. The hypothesis is tested that the location of farms along a gradient of bocage landscape--gradient of decreasing hedgerows density and increasing field size--influences their inner land use organization. The tests were based on mutual information and provided a hierarchy of driving factors of land use allocation in farms, as well as a classification of combinations of land use and field types. Three bocage sites--A, dense; B, intermediate; and C, open bocage--were chosen in northeast Brittany (France), on a 20 km2 micro-region of conventional dairy production based on maize (Zea mays L.), grassland and winter cereals, mainly wheat (Triticum spp.). In this context, land use allocation in a farm was better explained by the characteristics of the farm territory, i.e. the actual land used by a single farm, rather than by the characteristics of the farm household/enterprise, as defined by production, socioeconomic and technical features. Farms of the open bocage showed marked concentric patterns of land use away from the farmsteads, involving progressively pastures used by dairy cows, fodder crops, pastures used by livestock and cash crops. In these farms, there was a pronounced differentiation of the fields that held simultaneously constraints of surrounding hedgerows, small size and hydromorphy. Farms of the dense bocage site were more fragmented and constraints were distributed more diversely through fields, so that land use allocation was not optimized according to the distance from the farmstead. The concentric pattern of land use was therefore distorted in these farms. At a landscape level, such distortions led to a land use mosaic dominated by large patches of specialized fields in the open bocage, and to a fine grain and heterogeneous land use mosaic in the dense bocage. This study therefore demonstrated how the structure of the farm territory in different bocage landscapes has a major influence on land use allocation in farms. The results emphasize the interaction between land use and land structuring in farm quality of management, which in turn influences the landscape structure.