Reserva Agrícola Nacional, expans o urbana e fragmenta o da paisagem na “bacia leiteira primária” de Entre-Douro-e-Minho

Insufficient planned urban growth generates a large consumption, degradation and fragmentation of agricultural land, causes numerous pressures on management and planning of natural resources, and can lead to economic unfeasibility of farms and to the loss of an important economic base in agricultural regions. Around the Porto Metropolitan Area and in the Entre-Douro-e-Minho region, increasing built-up areas and densification of road network had strong impacts on rural land. Here is located Portugal s biggest "dairy region", with a high concentration of farms, and characterized by its intensive and mechanized farming, specialized in the dairy sector boosted by a competitive agri-food industry. The main purpose of this study was to quantify and analyse the fragmentation process of the National Agricultural Land Reserve zoning areas, resulting from the pressure caused by the built-up expansion. This analysis was done at two levels: the first, the patch level, aimed at achieving global values for the entire dairy region; and the second, the class level, focused on homogeneous spatial units that cover the entire area of study, allowing us to identify in more detail, after a multivariate statistical analysis, different intensities of landscape fragmentation. This study highlights the fundamental role of the metrics developed by Landscape Ecology, of Geographic Information Systems (GIS) and also of statistical methodologies, in the monitoring and assessment of development processes in prime farmland, as well as in landscape management and planning.