Abstract:

The landscape pattern and fragmentation in Beitun of Irtysh River Basin in Xingjian was analyzed by using RS and GIS in combining with the vegetation maps and field investigations. Quantitative indices of landscape pattern were chosen to examine landscape pattern and fragmentation. By using the software ERDAS image8-7, 7 primary landscape types and 10 secondary landscape types were classified, which including 5 primary vegetation types and 8 secondary vegetation types. The total classification accuracy was 87.2%. The primary vegetation types area percentage of farmland, riparian forest, wetland, grassland and desert vegetation was 16.5%, 2.6%, 1.6%, 10.5%, and 52.2% respectively. The patch maximal perimeter, patch maximal area and mean area indices of riparian forest were lower than other vegetation types, which disclosed that riparian forest distributed in the manner of smaller patches in the whole landscape. The value of mean patch shape, fractal dimension index, and edge density index of riparian forest were higher than other vegetation types, which indicated that riparian forest had more complex patch shape. All the pattern indices demonstrated that riparian forest was the most fragmented type in Irtysh River Basin, which was mainly due to that the riparian forest haven experienced high intensity and frequency of human disturbance since it had the highest biodiversity and most abundant natural resources in the landscape of Irtysh River Basin. The landscape diversity indices showed that the patch area distributed rather unevenly, the patch number distributed more evenly, however. 

Key words: Irtysh River Basin, landscape pattern, fragmentation, indices of landscape pattern