关键词: 喜马拉雅勒布沟, 小型兽类, 物种多样性垂直分布, 海拔梯度

Abstract:  Determining the vertical distribution of species diversity along altitudinal gradients is of critical importance in biodiversity and conservation research. Across a broad set of taxa, the hump-shaped pattern of species diversity is the most common one, and the vertical distribution of the small mammal community in the Middle Himalayas best fits a hump-shaped pattern. Since the Eastern Himalayas and Middle Himalays share many geographical and climatological conditions, we hypothesize that the vertical pattern of small mammal diversity in the East Himalayas also fit a mid-peak or humped pattern. Therefore, we conducted field surveys of two mammalian orders, Non-flying Small Mammal at an elevation of 2 300 – 5 000m, in the Lebu Valley of the East Himalayas. 45 sampling sites were set up, with each contained 9 segments distributing along an elevational gradient every 300 m. In total, our 16 200 traps  captured 372 specimens, which belonged to 10 species, 5 families and 3 mammalian orders. Our results indicated that the species richness of Non-flying Small Mammal in the Lebu valley reached a peak at an elevation of 2 600 – 2 900 m, and then decreased at higher elevations, displaying a mid-peak pattern. Based on this study, we hypothesize that the vertical distribution and species diversity of small mammals inhabiting valleys in the southern part of the Himalayas will exhibit a similar pattern in response to similar geographical and climatological conditions. Results suggest that geography and climate are key factors in understanding the vertical distribution of species diversity.

Key words: Lebu Valley in Himalayas, Small mammals, Vertical distribution of species diversity, Elevational gradient