Sedentary caribou, which are typically found in forested environments, reduce their movements and spread out at calving time to remain inconspicuous ( Bergerud 1988, 1996), giving birth in small wetlands ( Fuller and Keith 1981 Brown et al. Because of this susceptibility, parturient caribou have developed spacing strategies to alleviate losses ( Bergerud 1988, 1996), thus influencing the spatial and temporal dispersion of calves as a prey resource. 2003).Ĭaribou ( Rangifer tarandus) calves are highly vulnerable to predation during their 1st weeks of life (e.g., Whitten et al. Generalist consumers that live communally and are wide-ranging may be able to more effectively exploit aggregated and ephemeral resource pulses than solitary, specialized, and sedentary foragers ( Ostfeld and Keesing 2000 Wilmers et al. 2003), and differential effects may be especially pronounced when resources are pulsed ( Ostfeld and Keesing 2000 Wilmers et al. The response of consumers may vary depending upon their vagility and social structure ( Wilmers et al. Quantifying the variation in the spatiotemporal distribution, dispersion, and predictability of resources on a landscape is important because divergent patterns are likely to influence the spatial organization and abundance of consumers differently ( Wilmers et al. Dispersion and movement patterns varied with forest cover herds with less forest cover in their range were more aggregated and migratory than herds with more forest cover.Ĭalving, caribou, dispersion, distribution, mortality, predator, prey, Rangifer, resource, telemetry The most-aggregated herd remained so as it migrated from its calving ground, whereas the less-aggregated herd spread out and moved in a variety of predictable directions.
Postcalving (up to 9 weeks) distributions also varied among herds the 2 more-dispersed herds remained sedentary, whereas both highly aggregated herds migrated away from their calving grounds at the end of June. The dispersion of female caribou during calving varied among herds from highly aggregated (8% and 20% of herd range) to more dispersed (50–70% of herd range). Patterns of calf distribution were predictable in time and space from year to year, with an average distributional overlap of 68% between years. We used telemetry locations of 309 caribou calves and 100 adult females from 4 herds, 2008–2010, to estimate the spatiotemporal distribution of caribou calves during the time when they were most vulnerable to predation, to evaluate the predictability of the calf resource among years, and to assess the degree of aggregation during calving. These neonates are patchily distributed on the landscape therefore, to adequately understand predator-prey interactions, the temporal and geographic extent of the distribution of caribou calves must be identified so that current areas with calves can be differentiated from areas without calves. The recently diminished caribou ( Rangifer tarandus) population in insular Newfoundland, Canada, has been severely limited by predation on newborn calves.
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