ABSTRACT
Agricultural landscapes are extremely variable across the globe, varying with cropping system, topography and intensity of manage ment. The interactions between land use and landform are profound, leading to landscape mosaics. Going back to the beginnings of agricul ture, man has sought to define the areas of cropping and land ownership. As graziers, humans have also often sought to contain stock and protect them from wild animals. In extensive production systems, a balance be tween domestic and wild grazers is struck based on an understanding of carrying capacity. In intensive systems, land is typically enclosed and delineated with field boundaries. Most production areas are enclosed; that is, they are delimited or fenced into discrete areas. The advent of fencing had a profound impact on field margins and enclosure (Chapman
and Sheail, 1994), allowing stock impoundment and field delineation to be done more cheaply and easily than before. Prior to post and wire fencing, other structures were used. The so-called “dead hedge,” made of cut and woven shrub material is still used to some extent today, e.g., sheep hurdles made from hazel (Corylus avellana). In many areas of the world, hedges comprised of living trees, shrubs or other herbaceous flora, fulfill this role for stock impoundment and field delimitation. In England and northern France, the hedgerow has become a part of land scape heritage. Originally, these structures had important agricultural and production functions, though this is changing over time. Agricul tural development has been aided by enclosure but at the same time the structure of the landscape has changed. The landscape is never given over totally to agriculture or any single land use. Depending on climate, terrain and population, there are usually areas of watercourse, wood land, road verge or other semi-natural habitats that are less exploited. The juxtaposition of land uses, particularly farmed areas and natural habitat, form mosaics in the landscape (Burel and Baudry, 1999; Forman, 1995) .
