Arctic fox winter diet variation during damped lemming cycles estimated using molecular methods and fecal DNA

• Main Author: Dudenhoeffer, Megan
• Other Authors: Roth, James (Biological Sciences), Muthukumarana, Saman (Statistics) Petersen, Stephen (Biological Sciences, Assiniboine Park Conservancy)
• Format: Master Thesis
• Language: English
• Published: 2020
• Subjects: Arctic fox; Fecal DNA; Predator-prey dynamics; Arctic; Hudson; Hudson Bay; Arctic Fox; Churchill; Climate change; Tundra; Vulpes lagopus
• Online Access: http://hdl.handle.net/1993/34969

Climate-caused changes in prey abundance are altering predator-prey dynamics and food webs throughout the Arctic. Lemmings are important prey for many terrestrial Arctic predators and their annual population fluctuations drive reproduction and population dynamics of predators like Arctic foxes (Vulpes lagopus). Warmer winters throughout the Arctic have decreased snowpack quality, preventing lemmings from reaching their previous high abundances, which may reduce their impact on predator dynamics. Recent evidence suggests that the population of Arctic foxes near Churchill, Manitoba is declining, possibly due damped lemming abundances. I used DNA from non-invasively collected fecal samples to reconstruct Arctic fox winter diet and identify alternative prey consumption over years of varying lemming abundance. Using 644 fecal samples collected during April 2011-2018 and next generation sequencing, I found Arctic fox winter diet is driven by lemming abundance, despite lemming cycle damping. Lemming abundance negatively influenced the consumption of alternative prey such as marine resources. Additionally, Arctic fox winter diet included high proportions of meadow voles (Microtus pennsylvanicus), which were not detected on the coastal tundra prior to 2010, suggesting that climate change may be changing prey composition in the low Arctic. Fecal DNA also offers an alternative non-invasive solution to traditional mark-recapture methods for estimating wildlife populations, so I developed non-invasive sampling protocols for a population estimate of Arctic foxes. Specifically, I extracted DNA from Arctic fox fecal samples (n=19) collected in March-April 2019 and compared amplification rates between samples of various ages. I found no difference in amplification rates indicating that additional resources do not need to be allocated to field collection of fresh samples. This study provides practical information for future population estimate of Arctic foxes in western Hudson Bay. Additionally, this information can be applied to ...