Effects of winter-feeding on reindeer’s future ability to utilize natural pastures

Abstract: Winter feeding of reindeer (Rangifer tarandus tarandus) has become an increasingly common management action in reindeer husbandry in Sweden, Finland, and Norway when natural grazing resources are unavailable due to the loss of grazing grounds, disturbances, and icing events. In the short term, feeding increases survival and reproduction, but the long-term effects on reindeer’s ability to utilize natural pastures have not been investigated. Herders have raised concerns that fed reindeer, especially calves, do not utilize natural pastures as efficiently as other reindeer. In this thesis, I investigated the short- and long-term effects of winter feeding on reindeer with focus on habitat selection and future foraging behaviour. Interviews were conducted to collect experience-based knowledge on the effects of feeding among reindeer herders. An experimental study was conducted to test how winter feeding of calves during their first winter affects future habitat selection, foraging behaviour, and body weight. I found that there are several unintended effects of feeding that may compromise reindeer’s ability to use the natural pastures efficiently. In the interviews, the effects identified by herders were related to physical traits or behaviour; the reported effects varied between herders, as did the perception of whether an effect was positive or negative. In the experimental study, I found that reindeer calves which were fed in enclosures during their first winter of life were less likely to select areas with higher lichen abundance when on natural pasture compared to reindeer that had spent their first winter on natural pasture. Although, the control animals were also provided feed on pasture to some extent their first winter. Understanding the long-term impacts of winter feeding on reindeer and their ability to utilize natural pastures and adapt to changes in the environment may be crucial when evaluating the effects of different external forces on reindeer husbandry. Knowledge of the short- and long-term effects of feeding on reindeer is important for herders when evaluating if, when and how to feed their reindeer.