Effective interventions in order to reduce bear predation on reindeer calves.
Brown bear predation on reindeer was investigated in two reindeer herding cooperatives in northern Sweden. Calving areas were located in the forest region where there was a relatively high density of bears. Pregnant female reindeer were fitted with proximity transmitters and bears were followed by GPS. The GPS collars on the bears detected signals from the reindeer transmitters when closer than approximately 100 metres. GPS positions were recorded every minute for one hour following a reindeer-transmitter detection by a bear collar (otherwise positions were taken every 30 min). This enabled the detection of clusters of bear locations that were visited in order to find possible killed prey.
During 2010-2012, 23 bear individuals were followed during altogether 1478 days. Totally 335 calves and 18 adult female reindeer were found killed at the clusters. Over 99% of the calves were killed from 1 May until 9 June. The average predation rate from bears that were within the calving area during 1 May-15 June was 0.4 calves per bear, per day (95% confidence interval: 0.2-0.5 calves per day).
Reindeer calving in pens and culling of bears are tested as preventive measures during an on-going phase of the project (2013-2016). Preliminary results suggest that reindeer calving inside pens may be an effective intervention in order to reduce bear predation. Impaired health and wellfare for the reindeer may however reduce the net effect if hygiene within the fences cannot be kept good enough. Effects of culling of bears have not yet been evaluated.
Jens Karlsson (1), Ole-Gunnar Støen (1,2), Peter Segerström (2), Anna Skarin (1), Therese Sivertsen (1) and Birgitta Åhman (1)
(1) Swedish University of Agricultural Sciences, (2) Norwegian University of Life Sciences
Støen O-G, Sivertsen T R, Tallian A, Rauset G R, Kindberg J, Persson L-T, Stokke R, Skarin A, Segerström P and Frank J 2022. Brown bear predation on semi-domesticated reindeer and depredation compensations: Do the numbers add up? Global Ecology and Conservation e02168 10.1016/j.gecco.2022.e02168
Sivertsen et al. 2016. "Reindeer habitat selection under the risk of brown bear predation during calving season"
Karlsson et al. 2012. "Brown bear predation on reindeer calves a potential effects of three preventive measures" (in Swedish)
Frank et al. 2017. "Calving within enclosures and directed hunting as measures to reduce brown bear predation on reindeer" (in Swedish)
Sivetsen, Therese Ramberg, 2017. "Predation patterns, brown bear –reindeer interactions and landscape heterogeneity"
Kjellberg, Linnéa Eleonora, 2014. "Short window of opportunity for brown bear (Ursus arctos) predation on reindeer (Rangifer tarandus) calves"
Paul, Elisabeth, 2014. "Pregnancy detection in reindeer (Rangifer tarandus tarandus) : comparison of transrectal ultrasound, abdominal palpation and herders' visual cues in late gestation"
Persson, Anna-Marja, 2014. "Is the maternal condition important for domesticated reindeer calf survival?"
Wikström, Emil, 2014. Dödlighet hos renkalvar vid kalvning i hägn (Calf mortality in reindeer during calving in enclosures)
Korpinen, Caroline, 2017. "Maternal body condition, effect on time of calving, offspring survival and body weight in reindeer"
Gac Monreal, Ananai, 2017. "Reindeer Calving in Enclosures – Effect on the Mother's Activity"
For more information, contact Anna Skarin, anna.skarin@slu.se, 018-671954