부산대학교 도서관

Based on ecological parameters of 15 localities with birch mouse (Silista betulina) occurrence a model of its potential distribution in a part of the Bohemian Forest (Šumava) in Czech Republic was set up. The following habitat parameters were included into the model: land cover (six classes), proximity to next cover type (ten classes), proximity to a stream (five classes), altitude (seven classes), slope (seven classes), exposition (four classes). These parameters were derived from the Landsat 5 TM data and from digital elevation model using EASE/PACE software. All raster format data had a 30 m pixel size and all geographical information system layers were rectified into maps scale 1 " 25,000, Gauss-Krüger projection. For each of the six parameters two histograms were calculated. The first one displayed the frequency of a membership of a pixel to a class under a mask of the whole study area and the second histogram under a mask of the area of the birch mouse occurrence. The birch mouse preferred: the closest proximity to a stream (0-60m), flat terrain (slope < 5°), north-eastern and south-eastern expositions, the altitude between 700-900 m a. s. l., unmanaged meadows and pasture, boundaries between meadows and pastures or meadows and forests. The overall probability of the occurrence calculated according to these factors revealed areas of the most probable occurrence above all along the Vltava river system. This model was successfully verified by pitfall trap collection of birch mouse in three randomly chosen localities with the highest calculated probability of the occurrence.