Modelling vegetation patterns using natural and anthropogenic influence factors: preliminary experience with a GIS based model applied to an Alpine area

A modelling approach based on discriminant analysis and the GIS (geographical information system) is presented with the aim of identifying the influence of environmental parameters and human impact on the Alpine cultural landscape. For testing the model we used the vegetation patterns of an area of 5 km(2) between 1300 and 2300 m above sea level in the Central Alps (Passeier Valley, Italy). The overall prediction for the highly heterogeneous vegetation (a total of 21 different vegetation units characterized by high biodiversity) is in the order of 78% (pixel to pixel correspondence), the probability of correct classification by chance is only 21%. Only two vegetation units were totally misclassified, whereas six were classified correctly at almost 100%, a further seven at 60-80% and the remaining six at 20-50%. The proportion of unexplained variability in the research area may to some degree be attributed to the snow distribution pattern and to the use of a more detailed scale of spatial grazing habits. The most important lack of information, however, concerns land use history. Simulation analysis shows that human impact and elevation exert a major influence on the vegetation, whereas hydrological parameters and radiation do not greatly affect biodiversity and vegetation patterns in the study area. (C) 1998 Elsevier Science B.V. All rights reserved.