A beacon of dung: using lemming (Lemmus lemmus) winter nests and DNA analysis of faeces to further understand predator–prey dynamics in Northern Sweden

• Published in: Polar Biology
• Main Authors: Vigués, Jan, Menci, Silvia, Wilkinson, Caitlin, Le Vaillant, Maryline, Angerbjörn, Anders, Norén, Karin
• Other Authors: Stiftelsen Oscar och Lili Lamms Minne, Naturvårdsverket, Fjällräven International AB, Naturkompaniet AB, Stockholm University EcoClim Project, Göran Gustafssons Stiftelse för Naturvetenskaplig och Medicinsk Forskning, Stockholm University
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: General Agricultural and Biological Sciences; Arctic; Fennoscandia; Least; Lemmus lemmus; Mustela erminea; Mustela nivalis; Northern Sweden; Norwegian lemming; Polar Biology; Tundra
• Online Access: http://dx.doi.org/10.1007/s00300-021-02958-6; https://link.springer.com/content/pdf/10.1007/s00300-021-02958-6.pdf; https://link.springer.com/article/10.1007/s00300-021-02958-6/fulltext.html

Abstract The hypothesis that predation is the cause of the regular small rodent population oscillations observed in boreal and Arctic regions has long been debated. Within this hypothesis, it is proposed that the most likely predators to cause these destabilizing effects are sedentary specialists, with small mustelids being possible candidates. One such case would be the highly specialized least weasel ( Mustela nivalis ) driving the Norwegian lemming ( Lemmus lemmus ) cycle in Fennoscandia. These predators are often elusive and therefore distribution data can only be based on field signs, which is problematic when various mustelid species are sympatric, such as weasels and stoats ( Mustela erminea ). Here we present the results of using mustelid faeces in predated winter lemming nests to correctly identify the predator and thus discern which species exerts the strongest predation pressure on lemming winter populations. Samples were obtained during different phases in the lemming cycle, spanning 6 years, to account for different prey densities. Faecal mitochondrial DNA extraction and amplification of a 400-bp fragment was successful in 92/114 samples (81%); the sequencing of these samples proved that most predation occurrences (83%) could be attributed to the least weasel. These findings support the hypothesis that weasels in particular show high specificity in predation and could therefore be candidates to driving the lemming cycle in this area. We conclude that DNA analysis of faecal remains around predated nests can be a useful tool for further investigations concerning predator–prey interactions in the tundra.