Lemmings are key species in the arctic tundra. Yet, their whereabouts during the long winter is highly understudied. Luckily, we can use lemming winter nests as an indicator of habitat use by lemmings under the snow. Here we analyzed location data for more than 4200 collared lemming winter nests, collected each year since 1996 at Zackenberg in NE Greenland as part of Greenland Ecosystem Monitoring. We found that lemming select habitats where snow accumulates, but also showed that the strength of the habitat selection varies with lemming density. Moreover, by examining the winter nests for signs of breeding and predation by stoats, we found the larger lemming nests were found in the most preferred habitat (Salix snow beds), and that these were more likely to used for breeding, but also more likely to be depredated than smaller nests. These patterns suggest that the observed density-dependent habitat selection appeared to equalize fitness across the various habitat types.
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Reference: Schmidt, N.M., van Beest, F.M., Dupuch, A. et al. Long-term patterns in winter habitat selection, breeding and predation in a density-fluctuating, high Arctic lemming population. Oecologia (2021). https://doi.org/10.1007/s00442-021-04882-2
Text written by Niels Martin Schmidt.
Picture: Collared lemming (photo credit: Lars Holst Hansen)