The role of habitat quality and climate in the dynamics of occupancy and survival of a population of collared pikas (Ochotona collaris) in the Ruby Range, Yukon Territory

Abstract

I examined the role of habitat quality and climate in the dynamics of occupancy and survival of a population of collared pikas in the Yukon Territory, Canada. Annual surveys of marked individuals over an 11 year period (1999 to 2009) within a geographically isolated metapopulation were used to analyze relationships between pika occupancy dynamics and habitat quality and between recruitment and survival and measures of climate based on Pacific Decadal Oscillation (PDO) and downscaled regional climate (Climate WNA). Occupancy dynamics were correlated with the quality of habitat within pika territories in terms of solar radiation and vegetation quality using Normalized Difference Vegetation Index (NDVI) values derived from a remote sensing image as a proxy for above-ground biomass. Recruitment and survival of pikas were correlated with lagged PDO, with results varying by age, sex and aspect. These results demonstrate that occupancy of territories by collared pikas is non-random and based on habitat conditions and that climate has a strong influence on population dynamics at some life stages. This study also demonstrates applications of GIS and remote sensing data for studies at the scale of a small alpine mammal.