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Time to extinction in relation to mating system and type of density regulation in populations with two sexes

  • BE Saether
  • S Engen
  • R Lande
  • AP Moller
  • Staffan Bensch
  • Dennis Hasselquist
  • J Beier
  • B Leisler
Publishing year: 2004
Language: English
Pages: 925-934
Publication/Series: Journal of Animal Ecology
Volume: 73
Issue: 5
Document type: Journal article
Publisher: Federation of European Neuroscience Societies and Blackwell Publishing Ltd

Abstract english

1. Population viability models usually consider only the female segment of the population. However, random variation in sex ratio as well as the mating system may also affect variation in fitness among females. Here we develop population models incorporating demographic stochasticity in both sexes. Furthermore, we consider the effects on the estimated time to extinction and whether density regulation acts only on females or on total population size. 2. We applied these models to two populations of polygynous great reed warblers Acrocephalus arundinaceus L. with differences in population trends to investigate the importance of considering sex in population viability models. 3. Demographic stochasticity was larger in a polygynous than in a monogamous mating system. 4. The estimated time to extinction was considerably shorter for a monogamous than for a polygynous mating system, particularly if density regulation acted only on females than rather on the total population. 5. This study demonstrates that structure of mating system must be included when making population viability analysis based on counts of total population sizes. It is especially important to model the specific effects of density regulation on the two sexes.


  • Biological Sciences


  • Molecular Ecology and Evolution Lab
  • ISSN: 1365-2656
Dennis Hasselquist
E-mail: dennis [dot] hasselquist [at] biol [dot] lu [dot] se



+46 46 222 37 08



Research group


Doctoral students and postdocs

Research fellows


Jacob Roved

PhD Students, main supervisor

PhD Students, assistant supervisor


Interview about my research in the Swedish podcast "Forskarn & jag"