Arctic fox spatial dynamics as a driver of indirect interactions in the tundra.

Background/Question/Methods

The relative importance of biotic interactions as a drivers of species distribution is still controversial in ecology, despite strong evidence of their influence in some systems. Predation plays a central role in the structure and function of many arctic ecosystems. In heterogeneous landscapes, the movement of predators, shaped by physical constraints in the environment, the distribution of food resources, and social interactions, induces variation in the risk for prey. This heterogeneity in predation risk and how prey respond to it could be one of the key mechanisms driving species distribution in the Arctic tundra. The presence of refugia or environmental constraints that limit the availability of certain habitats could also influence species distribution by impacting both predator movements and prey habitat selection. The main objective of the project is to investigate the role of arctic fox predation and the physical environment in the distribution of prey in an Arctic terrestrial community. Here, we present our first results modelling arctic fox movement across the landscape.

Results/Conclusions

Using 8 years of GPS and ARGOS data collected on Bylot Island (Nunavut), we investigated how lemming and goose density influence arctic fox territory formation. We found that territory size increased with declining goose availability. Territories were also larger at low lemming densities but only in places where geese were unavailable. We present these results in the context of pulsed versus cyclic prey resource availability in this system and discuss their implication for other tundra nesting birds vulnerable to fox predation.