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Title: A stochastic model for ecological systems with strong nonlinear response to environmental drivers: application to two water-borne diseases
Authors: Codec, Claudia Torres
Lele, Subhash
Pascual, Mercedes
Bouma, Menno
Ko, Albert Icksang
Affilliation: Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.
University of Alberta. Department of Mathematical and Statistical Sciences. Edmonton Alberta, Canada.
University of Michigan. Department of Ecology and Evolutionary Biology. Ann Arbor, USA.
London School of Hygiene and Tropical Medicine. Department of Infectious and Tropical Diseases. Keppel Street, London.
Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil.
Abstract: Ecological systems with threshold behaviour show drastic shifts in population abundance or species diversity in response to small variation in critical parameters. Examples of threshold behaviour arise in resource competition theory, epidemiological theory and environmentally driven population dynamics, to name a few. Although expected from theory, thresholds may be difficult to detect in real datasets due to stochasticity, finite population size and confounding effects that soften the observed shifts and introduce variability in the data. Here, we propose a modelling framework for threshold responses to environmental drivers that allows for a flexible treatment of the transition between regimes, including variation in the sharpness of the transition and the variance of the response. The model assumes two underlying stochastic processes whose mixture determines the system's response. For environmentally driven systems, the mixture is a function of an environmental covariate and the response may exhibit strong nonlinearity. When applied to two datasets for water-borne diseases, the model was able to capture the effect of rainfall on the mean number of cases as well as the variance. A quantitative description of this kind of threshold behaviour is of more general application to predict the response of ecosystems and human health to climate change.
Keywords: Nonlinear
Disease dynamics
Extrinsic forcing
DeCS: Cólera/transmissão
Modelos Biológicos
Processos Estocásticos
Microbiologia da Água
Surtos de Doenças/estatística & dados numéricos
Estações do Ano
Fatores de Tempo
Issue Date: 2008
Publisher: The Royal Society
Citation: CODEC, C. T. et al. A stochastic model for ecological systems with strong nonlinear response to environmental drivers: application to two water-borne diseases. Journal of the Royal Society Interface, v. 5, n. 19, p. 247-252, 2008.
DOI: 10.1098/rsif.2007.1135
ISSN: 1742-5689
Copyright: restricted access
Appears in Collections:IOC - Artigos de Periódicos
BA - IGM - Artigos de Periódicos

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