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The S. Mamede Natural Park includes a mountain area, distributed along S. Salvador de Aramenha (Marvão municipality) and S. Julião (Portalegre municipality) regions. Contrasting with the population evolution in Portugal for the last 20 years (+4%) the population decreased 27% in Marvão and 6% in Portalegre. The number of people in farming business in both municipalities decreased around 34% (1989-1999). In S. Salvador the evolution was similar; however in S. Julião the decrease was just 13%. Did that land abandonment induce significant landscape changes? The land use was mapped in two different moments (1967 and 2001) and compared using ArcView GIS software. Official statistical data was used to complement the spatial analysis (population and agricultural census). In 1967, the intensive forest in S. Julião represented 20% from total area (4223 ha) as comparing with 9% from S. Salvador total area (4972 ha). The olive grove area was 18% in S. Julião and 29% in S. Salvador. Open fields represented 21% and 25% in S. Julião and S. Salvador respectively. The increase in intensive forest use (1967-2001) was more than 120% for both regions; however, these changes had different origins. In S. Salvador the increase was due to areas being occupied for several uses, namely shrublands, olive groves and orchards; in S. Julião the change resulted from the open field areas being replaced. The open fields area decreased 70%, representing only 6% of the total area of S. Julião at the present. Perhaps reflecting these changes, at S. Julião region the stock number did not change significantly as comparing with S. Salvador, where the number of heads increased (1972-1999) with emphasis on sheep (119 to 4377 ewes). Most likely, farming in open fields changed from cereals to pastures production supporting this livestock increase. New land uses emerging in S. Salvador (golf courses, water bodies and fabric) might be qualitatively important and reflect the establishment of other economic activities, absorbing people from farming business.

The study of wildlife communities to assess the landscape value is crucial in Landscape Ecology in order to develop bidiversity management strategies in rural landscapes and to assist land managers with their decision making processes. This poster reports the results achieved assessing biodiversity using landscape structural indicators. The main objective was to identify the landscape measures having a greater influence on the presence of avian communities in agrosystems located around Évora (South of Portugal). Birds were sampled along transects representing the different land use patterns occurring within the study area. Land use types/vegetation cover were mapped within buffers around those transects. The landscape indicators applied to each buffer are Shannon & Weaver’s Diversity Index (H’) (1962) for habitats biodiversity, Modified Simpson’s Index (E) (Romme & Knigth, 1982) for habitats heterogeneity, and organization pattern (D1) (O’Neill et al. 1988). Avian diversity was also measured using the Simpson’s index. ArcView software was used to map the land cover features and to calculate the values for the selected indices. The relation between the avian communities present and its attributes with the different landscape measures was analysed with multivariate statistics tools.

It is generally agreed that the choice of the most suitable uses based in soil and climatic factors, complemented with socio-economic criteria, promotes sustainable use of rural land. There are, however, different methodologies for defining the soil suitability to agroforestal systems or natural and seminatural ecosystems, including agricultural uses, forest plantations, agro-forestry areas and priority areas for nature conservation. Many of these methods rely on decision support systems based on multicriteria spatial analysis. In this study we intended to determine the different levels of suitability for agro-forestry use in a subregion located in the center of Portugal, near the border with Spain. To the effect we used a set of soil and topographic variables. The legal constraints and land cover were also included. The suitability evaluation was performed using the Analytic Hierarchy Process (AHP). A spatial analysis was also performed in order to confront the land use matrix with the soil potentiality. This analysis allows to identify areas where the use and management it is in accordance with their suitability, as well as areas where the use must be subject to a conversion or at least to a change of management mode.

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The development of a landscape ecological assessment and evaluation method applicable to the planning and management processes, and the impact assessment is the aim of this paper. A large scale characterization and evaluation methodology is tested in a 365 square Km area where an intensive ecological characterization was performed. This methodology is referred to two spatial referentials: land use distribution and homogeneous landscape units, which are described in terms of their spatial distribution and attributes, their matrix, patch, or corridor character, its permeability, connectivity and complementarity. A combination of both spatial referentials allows the application of algorithms evaluating different ecological values (conservation value, productivity, heritage value, functional value). The methodology is particularly suited to be used in the assessment of ecological impacts of land use changes and the construction of local and linear infrastructures.

Texto publicado no livro "Key Concepts in Landscape Ecology", editado por: J.W. Dover e R.G.H. Bunce (IALE-UK), correspondente aos Proceedings do Congresso Europeu da IALE em 1998.

Texto publicado no livro "Key Concepts in Landscape Ecology", editado por: J.W. Dover e R.G.H. Bunce (IALE-UK), correspondente aos Proceedings do Congresso Europeu da IALE em 1998.