Abstract
Reindeer and caribou are key environmental indicators that represent great socioeconomic and cultural value across the Arctic. In the light of global warming, the circumpolar decline in population sizes has thus raised major concerns. However, identifying how specific climate drivers may have contributed to this decline and will influence future population trajectories has been challenging. This is partly because proper estimation of population-dynamical parameters requires demographic models that include a mechanistic understanding of climate effects. In addition, our empirical linkage between climate and variation in key environmental variables, such as food availability during critical seasons, has been weak. Based on these challenges, this cross-disci plinary project will apply a mechanistic approach towards a predictive understanding of future population trajectories in wild reindeer on Svalbard, where a relatively simple trophic system offers a unique opportunity to examine the relative importance of climate drivers and net future implications of climate change. We will do this by taking advantage of a novel theoretical framework for age-structured population modelling and by integrating time-series data on climate, vegetation, snow-ice, and reindeer . Specifically, we will (1) estimate key population parameters and the age-specific components of climate effects on reindeer population dynamics using individual-based data; (2) identify the linkages between climate and reindeer food availability; (3) qu antify the relative importance of climate change during different seasons from long-term population time-series in three contrasting areas; and (4) predict population trajectories and time to local extinction under different climate scenarios, and how thi s varies in space. The project will provide tools for deriving a sustainable management of Svalbard reindeer and improve our predictive ability and mechanistic understanding of climate effects in arctic ungulates.
Norway