Climate change is occurring relatively rapidly in the Arctic zones at the top of the world.  If we are to understand and prepare for the impact of future climate change on more complex and diverse temperate and tropical communities, we should initially focus on monitoring and interpreting the current changes observed in Arctic host-parasite systems.  Several things work to our advantage in the Arctic: (1) the climate change signal is already pronounced and increasingly at a faster rate than in the tropics; (2) the host and parasite communities are less diverse and any analysis of change will have far fewer confounding variables and interactions. We have focused on analyses of parasite abundance data from hunted populations of caribou and musk-ox, and from populations of these species monitored by Canadian wildlife and veterinary services.  These data analyses are complemented by laboratory studies of the climate sensitivity of the infectious stages of the pathogens and the development of mathematical models for the parasite life cycles.

Results/Conclusions

All of our results suggest that parasite abundances and diversity are increasing in Arctic wildlife.  Two main mechanisms are driving this trend: (1) the life cycles of endemic parasites are operating more efficiently in the warmer and more prolonged Arctic summers; (2) range expansion of additional host species (moose and elk) has led to the introduction of novel pathogens for which Arctic hosts have had no previous exposure.