Spatial and temporal variability modify density dependence in populations of large herbivores

Wang, Guiming, Hobbs, N. Thompson, Boone, Randall B., Illius, Andrew W., Gordon, Iain J., Gross, John E., and Hamlin, Kenneth L. (2006) Spatial and temporal variability modify density dependence in populations of large herbivores. Ecology, 87 (1). pp. 95-102.

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A central challenge in ecology is to understand the interplay of internal and external controls on the growth of populations. We examined the effects of temporal variation in weather and spatial variation in vegetation on the strength of density dependence in populations of large herbivores. We fit three subsets of the model ln(N-t) = a + (1 + b) x ln(Nt-1) + c x ln((Nt-2)) to five time series of estimates (N-t) of abundance of ungulates in the Rocky Mountains, USA. The strength of density dependence was estimated by the magnitude of the coefficient b. We regressed the estimates of b on indices of temporal heterogeneity in weather and spatial heterogeneity in resources. The 95% posterior intervals of the slopes of these regressions showed that temporal heterogeneity strengthened density-dependent feedbacks to population growth, whereas spatial heterogeneity weakened them. This finding offers the first empirical evidence that density dependence responds in-different ways to spatial heterogeneity and temporal heterogeneity.

Item ID: 42520
Item Type: Article (Research - C1)
ISSN: 1939-9170
Keywords: Bayesian hierarchical model, climate variability, density dependence, large herbivores, Markov Chain Monte Carlo Method, normalized difference vegetation index, population dynamics, Rocky Mountains, spatial variability, temporal variability
Funders: US National Science Foundation (NSF), University of California, Santa Barbara, State of California
Projects and Grants: NSF DEB-94-21535, NSF DEB 0119618
Date Deposited: 10 Feb 2016 07:43
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060207 Population Ecology @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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