Arctic Wildlife Observatories Linking Vulnerable EcoSystems (ArcticWOLVES)

Deep snow provides insulation from the cold air temperature, protection from predators and allows winter reproduction, upon which depend the periodic population irruptions of small mammals. However, deep snow is spatially uncommon in the Arctic, thus the distribution and spatial extent of good quality winter habitat may be limiting population irruptions in some regions or years. Radio-tracking of tundra predators such as snowy owls and arctic foxes revealed that they travel over very large areas and they can extensively use the marine ecosystem during winter, when terrestrial food resources are scarce.

Snowy owls in particular display a remarkab le nomadism when searching for suitable nesting sites in spring and an outstanding ability to find locally abundant lemming populations, which may contribute to the regional synchrony of lemming population dynamics. We found evidence that the strength of predation decreases with latitude. Using artificial birds¿ nests, we showed that risk of predation decreases by as much as 66% between 53 and 82 N latitude (a 3,400 km distance).

We also found that soil-plant-herbivore interactions are quite sensitive to climate warming. On the one hand, earlier thaw or increasing freeze-thaw cycles will likely result in a loss of soil nutrients in some wetland ecosystems, leading to a decrease in plant production and food resource for herbivores. On the other hand, earlier and warmer springs could have a negative impact on the synchrony between the reproductive phenology of herbivores and plant growth, leading to reduced annual production.