Oral Presentation- Symposium 12th International Mammalogical Congress

Elevational diversity patterns of small mammals in the Western Himalayas (#37)

Vivek Ramachandran 1 , Uma Ramakrishnan 1
  1. Nation Centre for Biological Sciences, Bangalore, Karnataka, India

The Himalayas, located in the transition zone of three biogeographic zones, is a global biodiversity hotspot. Despite this, the distributions of small mammals in the western Himalayas are poorly known, with most surveys having been carried out over a century ago. We sampled non-volant small mammals along an elevation gradient from the Kashmir valley (1500 m) to the Tibetan plateau (5500 m) using a systematic methodology with standard Sherman and Tomahawk traps, in the Kashmir Himalayas, India. Using locally-weighted sums of squares and quadratic polynomial regressions, species richness of small mammals showed a bimodal peak at 2000 m and 3500 m, declining at lower and higher elevations. The areas where much overlapping of species occurs are the elevations where climate and vegetation change rapidly at the transition from mixed-broadleaved to conifers (~2200m) and the tree-line around 3300 m in the Western Himalayas. Murid rodents of the genus Apodemus, Niviventer and Rattus dominated the community in the lower elevations, replaced by voles of the genus Microtus, Alticola and Hyperacrius and Ochotona pikas in the alpine meadows, screes and Tibetan steppe. At least four species of Apodemus mice and four species of Alticola voles were sampled and subsequent genetic identification and phylogenetic analysis could potentially reveal new species in this region. Preliminary analysis of stable isotopes of carbon and nitrogen from fur samples show niche segregation among Muridae and Arvicolinae, possibly indicating a dietary transition from C3 to C4 plants mirroring the community turnover across the tree-line.