Impact of climate change on the small mammal community of the Yukon boreal forest.

Long-term monitoring is critical to determine the stability and sustainability of wildlife populations, and if change has occurred, why. We have followed population density changes in the small mammal community in the boreal forest of the southern Yukon for 46 years with density estimates by live trapping on 3-5 unmanipulated grids in spring and autumn. This community consists of 10 species and was responsible for 9% of the energy flow in the herbivore component of this ecosystem from 1986 to 1996, but this increased to 38% from 2003 to 2014. Small mammals, although small in size, are large in the transfer of energy from plants to predators and decomposers. Four species form the bulk of the biomass. There was a shift in the dominant species from the 1970s to the 2000s, with Myodes rutilus increasing in relative abundance by 22% and Peromyscus maniculatus decreasing by 22%. From 2007 to 2018, Myodes comprised 63% of the catch, Peromyscus 20%, and Microtus species 17%. Possible causes of these changes involve climate change, which is increasing primary production in this boreal forest, and an associated increase in the abundance of 3 rodent predators, marten (Martes americana), ermine (Mustela ermine) and coyotes (Canis latrans). Following and understanding these and potential future changes will require long-term monitoring studies on a large scale to measure metapopulation dynamics. The small mammal community in northern Canada is being affected by climate change and cannot remain stable. Changes will be critically dependent on food-web interactions that are species-specific.

Cite this article as:

Krebs CJ, Boonstra R, Gilbert BS, Kenney AJ, Boutin S (2019). Impact of climate change on the small mammal community of the Yukon boreal forest. Integrative Zoology 14, 528–41.

Additional supporting information may be found in the online version of this article at the publisher's website.

Figure S1 Red‐backed voles (Myodes rutilus) instantaneous rate of change from autumn to the following spring in relation to winter maximum snow depth, 2000–2018 at Kluane Lake. There is an indication of a weak positive relationship (R = 0.15, P = 0.10. Average snow depth over winter is highly correlated with maximum snow depth (r = 0.82, n = 18).

Figure S2 Deer mouse (Peromyscus maniculatus) autumn population density 1976–2018 at Kluane Lake, with 95% confidence limits. No deer mice were live trapped in the forest between 1990 and 1995 in spite of extensive trapping. These data are discussed in Krebs et al. (2018b). Figure updated from Krebs et al. (2018b) with permission.

Supporting Information

Click here for additional data file.