Context-dependent fitness costs of reproduction despite stable body mass costs in an Arctic herbivore.

Autor: Pigeon G; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway., Albon S; The James Hutton Institute, Aberdeen, UK., Loe LE; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway., Bischof R; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway., Bonenfant C; UMR CNRS 5558, Laboratoire de Biométrie et Biologie Évolutive, Université de Lyon, Villeurbanne Cedex, France., Forchhammer M; The University Centre in Svalbard, Longyearbyen, Norway., Irvine RJ; The James Hutton Institute, Aberdeen, UK., Ropstad E; Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway., Veiberg V; Norwegian Institute for Nature Research, Trondheim, Norway., Stien A; Department for Arctic Ecology, Norwegian Institute for Nature Research, Fram Centre, Tromsø, Norway.
Jazyk: angličtina
Zdroj: The Journal of animal ecology [J Anim Ecol] 2022 Jan; Vol. 91 (1), pp. 61-73. Date of Electronic Publication: 2021 Oct 03.
DOI: 10.1111/1365-2656.13593
Abstrakt: The cost of reproduction on demographic rates is often assumed to operate through changing body condition. Several studies have found that reproduction depresses body mass more if the current conditions are severe, such as high population densities or adverse weather, than under benign environmental conditions. However, few studies have investigated the association between the fitness components and body mass costs of reproduction. Using 25 years of individual-based capture-recapture data from Svalbard reindeer Rangifer tarandus platyrhynchus, we built a novel Bayesian state-space model that jointly estimated interannual change in mass, annual reproductive success and survival, while accounting for incomplete observations. The model allowed us to partition the differential effects of intrinsic and extrinsic factors on both non-reproductive mass change and the body mass cost of reproduction, and to quantify their consequences on demographic rates. Contrary to our expectation, the body mass cost of reproduction (mean = -5.8 kg) varied little between years (CV = 0.08), whereas the between-year variation in body mass changes, that were independent of the previous year's reproductive state, varied substantially (CV = 0.4) in relation to autumn temperature and the amount of rain-on-snow in winter. This body mass loss led to a cost of reproduction on the next reproduction, which was amplified by the same environmental covariates, from a 10% reduction in reproductive success in benign years, to a 50% reduction in harsh years. The reproductive mass loss also resulted in a small reduction in survival. Our results show how demographic costs of reproduction, driven by interannual fluctuations in individual body condition, result from the balance between body mass costs of reproduction and body mass changes that are independent of previous reproductive state. We illustrate how a strong context-dependent fitness cost of reproduction can occur, despite a relatively fixed body mass cost of reproduction. This suggests that female reindeer display a very conservative energy allocation strategy, either aborting their reproductive attempt at an early stage or weaning at a relatively constant cost. Such a strategy might be common in species living in a highly stochastic and food limited environment.
(© 2021 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)
Databáze: MEDLINE
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