University of Oulu

Pöllänen, A.T., Pakanen, VM. & Paasivaara, A. Survival and cause-specific mortality in adult females of a northern migratory ungulate. Eur J Wildl Res 69, 60 (2023).

Survival and cause‑specific mortality in adult females of a northern migratory ungulate

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Author: Pöllänen, Antti T.1,2; Pakanen, Veli‑Matti1; Paasivaara, Antti2
Organizations: 1Ecology and Genetics Research Unit, University of Oulu, PO Box 3000, Oulu 90014, Finland
2Natural Resources Institute Finland, Paavo Havaksen Tie 3, Oulu 90570, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.7 MB)
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Language: English
Published: Springer Nature, 2023
Publish Date: 2023-09-07


Survival of ungulates can vary seasonally due to changing environmental conditions, e.g. weather or predation pressure. The wild forest reindeer (Rangifer tarandus fennicus, “WFR”) migrate between calving and wintering grounds. The annual cycle of female WFR includes four main seasons (wintering, calving, rutting and autumn migration) during which they are subject to different conditions, but almost nothing is known about their survival or mortality patterns. We measured survival in 305 GPS-tagged female WFR in two subpopulations in Finland (2010–2022). Data were analysed for inter-annual and seasonal patterns in survival and cause-specific mortality (predation, traffic, accidents and unknown causes) with known-fate models. Inter-annual survival in Suomenselkä (mean 0.90) showed an increasing trend during the study and was higher than in Kainuu (mean 0.84) which showed a declining trend. Seasonal variation in survival was population dependent. Survival was lowest in Kainuu during the winter while in Suomenselkä, it was lowest during autumn migration. Concerning cause-specific mortality, seasonal variation mirrored variation in predation that was the primary cause of mortality (55% of cases). Wolves (Canis lupus) killed the majority of predated individuals (58%). Predation rates were two times higher in Kainuu where the wolf density was higher. We provide the first adult survival estimates for WFR and show that the seasonal variation in survival is clearly different between these two northern ungulate populations. This indicates that seasonal variation in survival is determined by site-dependent factors and cannot be generalised across populations.

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Series: European journal of wildlife research
ISSN: 1612-4642
ISSN-E: 1439-0574
ISSN-L: 1612-4642
Volume: 69
Issue: 3
Article number: 60
DOI: 10.1007/s10344-023-01686-y
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: Open Access funding provided by University of Oulu including Oulu University Hospital. This study was funded by The Finnish Cultural Foundation—Kainuu Regional Fund, WildForestReindeerLife project of European Union and partially by The Finnish Natural Resources Institute.
Copyright information: © The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit