Demography and metapopulation dynamics of collared pikas ( Ochotona collaris) in the southwest Yukon
Dates
Year
2002
Citation
Franken, Renee Joline, 2002, Demography and metapopulation dynamics of collared pikas ( Ochotona collaris) in the southwest Yukon: University of Alberta (Canada).
Summary
I conducted the first demographic analysis of collared pikas in the southwest Yukon. Individual growth rates were best described using a Gompertz model, and these rates were higher than those reported from southern latitudes. Parturition dates were asynchronous and weakly related to snow accumulation. Over-winter survival was low (34% adults; 25% juveniles), and juvenile survival was not related to dispersal, patch density, or parturition date. Survival was not sex-biased but varied depending on year of birth, aspect and other habitat variables, the latter showing considerable variation among years. A minimum of 34% of juveniles made inter-patch movements (mean of 332m); and both sexes dispersed with equal frequency. Pikas settled [...]
Summary
I conducted the first demographic analysis of collared pikas in the southwest Yukon. Individual growth rates were best described using a Gompertz model, and these rates were higher than those reported from southern latitudes. Parturition dates were asynchronous and weakly related to snow accumulation. Over-winter survival was low (34% adults; 25% juveniles), and juvenile survival was not related to dispersal, patch density, or parturition date. Survival was not sex-biased but varied depending on year of birth, aspect and other habitat variables, the latter showing considerable variation among years. A minimum of 34% of juveniles made inter-patch movements (mean of 332m); and both sexes dispersed with equal frequency. Pikas settled towards neighbors of the opposite sex, but males were more likely to recolonize unoccupied patches than females. Patch size and isolation only partly explained patterns of recolonization and extinction of talus patches by pikas. Habitat quality was also important in these processes.
