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Phase- and density-dependent population dynamics in Norwegian lemmings: interaction between deterministic and stochastic processes
Journal article   Open access

Phase- and density-dependent population dynamics in Norwegian lemmings: interaction between deterministic and stochastic processes

N. C Stenseth, K Chan, E Framstad and H Tong
Proceedings of the Royal Society. B, Biological sciences, Vol.265(1409), pp.1957-1968
10/22/1998
DOI: 10.1098/rspb.1998.0526
PMCID: PMC1689487
PMID: 9821362
url
https://doi.org/10.1098/rspb.1998.0526View
Published (Version of record) Open Access

Abstract

We analysed two 26-year long (1970 to 1995) time-series on annual population growth rates of Norwegian lemmings (Lemmus lemmus) from Finse, south Norway, using a threshold autoregressive (TAR) approach. We demonstrate that the population dynamics is both phase- and density-dependent. The phase-dependence accounts for the observed nonlinearity. We used the deduced stochastic model structure as a basis for evaluating the dynamic properties of this system. The dynamics is characterized either by limit cycles or chaos (the latter with a strong semi-periodic component). Stochasticity is seen to play an important role in the determination of the periodicity. The ecological implications of these statistical and mathematical results are discussed.
continuous TAR models deterministic processes dynamic stability analysis microtine population cycles nonlinear dynamics stochastic processes

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