Forest Fragmentation and Tree Diversity in Khangchendzonga Biosphere Reserve, Sikkim

The pattern of forest fragmentation was studied in Khangchendzonga Biosphere Reserve, Sikkim (KBR) and tree diversity was correlated with fragment size. A total of 23 forestfragments were identified in the KBR after intensive survey, of which ten fragments were in temperate forest, 12 in sub-alpine forest and one in sub-tropical forest. Maximum numbers of fragments were in 2-6 ha size classes. Landslide, wind storm and grazing by livestock herds were identified as the causes of forest fragmentation in KBR. The fragmentation of forest significantly impacted species composition, and community structure of trees in the forest, as evidenced from the differences in these attributes between the fragments and adjacent continuous forests.