Phase- and density-dependent population dynamics in Norwegian lemmings: interaction between deterministic and stochastic processes
We analysed two 26-year long (1970-1995) 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-dependen...
Published in: | Proceedings of the Royal Society of London. Series B: Biological Sciences |
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Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
The Royal Society
1998
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Subjects: | |
Online Access: | https://kar.kent.ac.uk/17174/ https://doi.org/10.1098/rspb.1998.0526 |
Summary: | We analysed two 26-year long (1970-1995) 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. |
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