A1 Refereed original research article in a scientific journal
Generation time and temporal scaling of bird population dynamics
Authors: Saether BE, Lande R, Engen S, Weimerskirch H, Lillegard M, Altwegg R, Becker PH, Bregnballe T, Brommer JE, McCleery RH, Merila J, Nyholm E, Rendell W, Robertson RR, Tryjanowski P, Visser ME
Publisher: NATURE PUBLISHING GROUP
Publication year: 2005
Journal:: Nature
Journal name in source: NATURE
Journal acronym: NATURE
Volume: 436
Issue: 7047
First page : 99
Last page: 102
Number of pages: 4
ISSN: 0028-0836
DOI: https://doi.org/10.1038/nature03666
Abstract
Theoretical studies have shown that variation in density regulation strongly influences population dynamics(1), yet our understanding of factors influencing the strength of density dependence in natural populations still is limited(2). Consequently, few general hypotheses have been advanced to explain the large differences between species in the magnitude of population fluctuations(3-6). One reason for this is that the detection of density regulation in population time series is complicated by time lags induced by the life history of species(7,8) that make it difficult to separate the relative contributions of intrinsic and extrinsic factors to the population dynamics. Here we use population time series for 23 bird species to estimate parameters of a stochastic density-dependent age-structured model. We show that both the strength of total density dependence in the life history and the magnitude of environmental stochasticity, including transient fluctuations in age structure, increase with generation time. These results indicate that the relationships between demographic and life-history traits in birds(9,10) translate into distinct population dynamical patterns that are apparent only on a scale of generations.
Theoretical studies have shown that variation in density regulation strongly influences population dynamics(1), yet our understanding of factors influencing the strength of density dependence in natural populations still is limited(2). Consequently, few general hypotheses have been advanced to explain the large differences between species in the magnitude of population fluctuations(3-6). One reason for this is that the detection of density regulation in population time series is complicated by time lags induced by the life history of species(7,8) that make it difficult to separate the relative contributions of intrinsic and extrinsic factors to the population dynamics. Here we use population time series for 23 bird species to estimate parameters of a stochastic density-dependent age-structured model. We show that both the strength of total density dependence in the life history and the magnitude of environmental stochasticity, including transient fluctuations in age structure, increase with generation time. These results indicate that the relationships between demographic and life-history traits in birds(9,10) translate into distinct population dynamical patterns that are apparent only on a scale of generations.
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