Abstract
Mechanisms generating the well-known 3-5 year cyclic fluctuations in densities of northern small rodents (voles and lemmings) have remained an ecological puzzle for decades. The hypothesis that these fluctuations are caused by delayed density-dependent impacts of predators was tested by replicated field experimentation in western Finland. We reduced densities of all main mammalian and avian predators through a 3 year vole cycle and compared vole abundances between four reduction and four control areas (each 2.5-3 km(2)). The reduction of predator densities increased the autumn density of voles fourfold in the low phase, accelerated the increase twofold, increased the autumn density of voles twofold in the peak phase, and retarded the initiation of decline of the vole cycle. Extrapolating these experimental results to their expected long-term dynamic effects through a demographic model produces changes from regular multiannual cycles to annual fluctuations with declining densities of specialist predators. This supports the findings of the field experiment and is in agreement with the predation hypothesis. We conclude that predators may indeed generate the cyclic population fluctuations of voles observed in northern Europe.
Full Text
The Full Text of this article is available as a PDF (236.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Agrell J., Erlinge S., Nelson J., Nilsson C., Persson I. Delayed density-dependence in a small-rodent population. Proc Biol Sci. 1995 Oct 23;262(1363):65–70. doi: 10.1098/rspb.1995.0177. [DOI] [PubMed] [Google Scholar]
- Hanski I., Turchin P., Korpimäki E., Henttonen H. Population oscillations of boreal rodents: regulation by mustelid predators leads to chaos. Nature. 1993 Jul 15;364(6434):232–235. doi: 10.1038/364232a0. [DOI] [PubMed] [Google Scholar]
- Hudson P. J., Dobson A. P., Newborn D. Prevention of population cycles by parasite removal. Science. 1998 Dec 18;282(5397):2256–2258. doi: 10.1126/science.282.5397.2256. [DOI] [PubMed] [Google Scholar]
- Klemola T., Koivula M., Korpimäki E., Norrdahl K. Experimental tests of predation and food hypotheses for population cycles of voles. Proc Biol Sci. 2000 Feb 22;267(1441):351–356. doi: 10.1098/rspb.2000.1008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Krebs C. J., Boutin S., Boonstra R., Sinclair A. R., Smith J. N., Dale M. R., Martin K., Turkington R. Impact of food and predation on the snowshoe hare cycle. Science. 1995 Aug 25;269(5227):1112–1115. doi: 10.1126/science.269.5227.1112. [DOI] [PubMed] [Google Scholar]
- Lindström J., Ranta E., Kokko H., Lundberg P., Kaitala V. From arctic lemmings to adaptive dynamics: Charles Elton's legacy in population ecology. Biol Rev Camb Philos Soc. 2001 Feb;76(1):129–158. doi: 10.1017/s1464793100005637. [DOI] [PubMed] [Google Scholar]
- Norrdahl K., Korpimäki E. Mortality factors in a cyclic vole population. Proc Biol Sci. 1995 Jul 22;261(1360):49–53. doi: 10.1098/rspb.1995.0116. [DOI] [PubMed] [Google Scholar]
- Norrdahl K. Population cycles in northern small mammals. Biol Rev Camb Philos Soc. 1995 Nov;70(4):621–637. doi: 10.1111/j.1469-185x.1995.tb01654.x. [DOI] [PubMed] [Google Scholar]
- Stenseth N. C., Bjørnstad O. N., Falck W. Is spacing behaviour coupled with predation causing the microtine density cycle? A synthesis of current process-oriented and pattern-oriented studies. Proc Biol Sci. 1996 Nov 22;263(1376):1423–1435. doi: 10.1098/rspb.1996.0208. [DOI] [PubMed] [Google Scholar]
- Stenseth N. C., Falck W., Bjornstad O. N., Krebs C. J. Population regulation in snowshoe hare and Canadian lynx: asymmetric food web configurations between hare and lynx. Proc Natl Acad Sci U S A. 1997 May 13;94(10):5147–5152. doi: 10.1073/pnas.94.10.5147. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stenseth N. C. Snowshoe hare populations: squeezed from below and above. Science. 1995 Aug 25;269(5227):1061–1062. doi: 10.1126/science.269.5227.1061. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.