La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Relationship between vegetation units and terrain parameters in vegetation maps using GIS tools: A case study in the eastern Pyrenees (1999)
Auteurs :	Juli G. Pausas, Auteur ; Jordi Carreras, Auteur
Type de document :	Article
Dans :	Ecologia Mediterranea (25(1) March, 1999)
Article en page(s) :	57-73
Résumé :	A 1:50,000 vegetation map covering 486 km2 with 78 cartographic units was digitised and "rasterised" to 150 X 150 m grid-cell. Vegetation units were based on floristic criteria. Four other raster layers were also produced to the same format: slopes, aspect, altitude and bedrock type. The relationship of vegetation units (total of 58 units) and physiognomic communities (forests, shrublands, grasslands, agricultural land and rocky areas) with terrain parameters was studied by overlaying these raster layers. Spatial structure (autocorrelation, fragmentation and shape) of the forest communities was also studied. The results show that the area is covered mainly by a large number of forest communities and grasslands, however most of these vegetation types cover a small area or are highly fragmented. Vegetation units and physiognomic communities are highly related to terrain parameters, among which altitude and bedrock type are the most important. Nearly half of the potential forest area isdeforested, specially at high altitude. The application of accurate vegetation maps linked with GIS to environmental conservation and management is discussed.

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