Influence of snow, food, and rock cover on Royle's pika abundance in western Himalaya

Abstract

Knowledge on demographic responses to environmental and microhabitat factors are crucial to understand the ecological consequences of climate change predictions for species that live in isolated mountainous habitat, such as the Royle's pika. We examined the influence of snow attributes, food availability, and rock cover on adult and juvenile pika counts and juvenile emergence date based on spatiotempora) variation in these parameters at 10 permanent plots (0.25 ha squares) along an attitudinal gradient of Kedamath Wildlife Sanctuary during the predispersal period spanning four years. Pika count and its interannual variability at plots were estimated at 4.06MC, ± 0.2lsE and 19.65 ± 1.71% CV respectively. Regression analysis showed that spatiotemporal variation in adult counts was related to the interactive effect of snow-cover period and altitude wherein counts increased with snow-cover period only in lower altitudes (β = 0.26 ± 0.08). Juvenile count was related to spring snow- depth (β = 0.074 ± 0.037). Litter number was typically one. Our results confirm the influence of snow as thermal insulator (to pika and their food plants) on population dynamics of small mammals. We also highlight that adult and juvenile populations might be governed by different factors, invoking further studies on age-stratified assessment of population responses to climate change.