Voles and weasels in the boreal Fennoscandian small mammal community: what happens if the least weasel disappears due to climate change?

Hannu Ylönen,Janne Sundell,Thorbjörn Sievert,Marko Haapakoski

doi:10.1111/1749-4877.12388

Hannu Ylönen, Janne Sundell + Show 2 more

Open Access

https://doi.org/10.1111/1749-4877.12388

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Abstract

Climate change, habitat loss and fragmentation are major threats for populations and a challenge for individual behavior, interactions and survival. Predator–prey interactions are modified by climate processes. In the northern latitudes, strong seasonality is changing and the main predicted feature is shortening and instability of winter. Vole populations in the boreal Fennoscandia exhibit multiannual cycles. High amplitude peak numbers of voles and dramatic population lows alternate in 3–5‐year cycles shortening from North to South. One key factor, or driver, promoting the population crash and causing extreme extended lows, is suggested to be predation by the least weasel. We review the arms race between prey voles and weasels through the multiannual density fluctuation, affected by climate change, and especially the changes in the duration and stability of snow cover. For ground‐dwelling small mammals, snow provides thermoregulation and shelter for nest sites, and helps them hide from predators. Predicted increases in the instability of winter forms a major challenge for species with coat color change between brown summer camouflage and white winter coat. One of these is the least weasel, Mustela nivalis nivalis. Increased vulnerability of wrong‐colored weasels to predation affects vole populations and may have dramatic effects on vole dynamics. It may have cascading effects on other small rodent–predator interactions and even on plant–animal interactions and forest dynamics.

Highlights

Correspondence: Hannu Ylönen, Department of Biological and Environmental Science and Konnevesi Research Station, University of Jyväskylä, PO Box 35, FI-40014 Jyväskylä, Finland.Anthropogenic climate change has created many stressors that threaten wild populations failing to adapt to novel conditions
For ground-dwelling small mammals, snow provides thermoregulation and shelter for nest sites, and helps them hide from predators
For thousands of years, shortening of day length and onset of winter have been in strict correlation but not necessarily anymore. This makes weasels vulnerable to climate change-caused mismatch in color molting so that they are no longer camouflaging with the background color due unpredictable snow cover

Summary

INTRODUCTION

Climate change is causing unpredictability of the onset and end of winters and has the potential to threaten the viability of specialist predator species, possibly The reason why this weasel is so important is that it is thought to regulate small mammal populations such as those of voles and shrews in Scandinavia (Hanski et al.2001). If the high impact of weasels in the multiannual pattern of vole dynamics (Hanski et al 2001) were to change due to climate change, the decline or disappearance of specialist predators might dampen small mammal population cycles (Korpela et al 2014). The resident specialist predators of small rodents, which are often small carnivorous mammals, especially the small mustelids the weasel and the stoat, cannot travel long distances and are highly dependent on local prey availability They tend to have a destabilizing effect on prey populations (Hanski et al 1993). This gradient is associated with climate with longer duration of snow cover and snow thickness in the north, which gives partial protection from many non-specialized predators (Hansson & Henttonen 1985)

BOREAL VOLE CYCLE AND

Recognition of fear

Weasel behavior and survival adaptations along the vole cycle

Fatal coat color dilemma along climate change

Findings

CONCLUSIONS