Simulation of structured populations in chemically stressed environments

A heterogenous environment usually impacts, and sometimes determines, the structure and function of organisms in a population. We simulate the effects of a chemical on a population in a spatially heterogeneous environment to determine perceived stressor and spatial effects on dynamic behavior of the...

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Main Authors: Thomas G. Hallam, Qingping Deng
Format: Article
Language:English
Published: AIMS Press 2005-10-01
Series:Mathematical Biosciences and Engineering
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Online Access:https://www.aimspress.com/article/doi/10.3934/mbe.2006.3.51
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author Thomas G. Hallam
Qingping Deng
author_facet Thomas G. Hallam
Qingping Deng
author_sort Thomas G. Hallam
collection DOAJ
description A heterogenous environment usually impacts, and sometimes determines, the structure and function of organisms in a population. We simulate the effects of a chemical on a population in a spatially heterogeneous environment to determine perceived stressor and spatial effects on dynamic behavior of the population. The population is assumed to be physiologically structured and composed of individuals having both sessile and mobile life history stages, who utilize energetically-controlled, resource-directed, chemical-avoidance advective movements and are subjected to random or density dependent diffusion. From a modeling perspective, the presence of a chemical in the environment requires introduction of both an exposure model and an effects module. The spatial location of the chemical stressor determines the exposure levels and ultimately the effects on the population while the relative location of the resource and organism determines growth. We develop a mathematical model, the numerical analysis for this model, and the simulation techniques necessary to solve the problem of population dynamics in an environment where heterogeneity is generated by resource and chemical stressor. In the simulations, the chemical is assumed to be a nonpolar narcotic and the individuals respond to the chemical via both physiological response and by physical movement. In the absence of a chemical stressor, simulation experiments indicate that despite a propensity to move to regions of higher resource density, organisms need not concentrate in the vicinity of high levels of resource. We focus on the dynamical variations due to advection induced by the toxicant. It is demonstrated that the relationship between resource levels and toxicant concentrations is crucial in determining persistence or extinction of the population.
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spelling doaj-art-5efa78ec84404268b8f76af9632f5ad62025-01-24T01:51:11ZengAIMS PressMathematical Biosciences and Engineering1551-00182005-10-0131516510.3934/mbe.2006.3.51Simulation of structured populations in chemically stressed environmentsThomas G. Hallam0Qingping Deng1Department of Ecology and Evolutional Biology, University of Tennessee, Knoxville, TN 37996The Institute for Environmental Modeling, University of Tennessee, Knoxville, TN 37996A heterogenous environment usually impacts, and sometimes determines, the structure and function of organisms in a population. We simulate the effects of a chemical on a population in a spatially heterogeneous environment to determine perceived stressor and spatial effects on dynamic behavior of the population. The population is assumed to be physiologically structured and composed of individuals having both sessile and mobile life history stages, who utilize energetically-controlled, resource-directed, chemical-avoidance advective movements and are subjected to random or density dependent diffusion. From a modeling perspective, the presence of a chemical in the environment requires introduction of both an exposure model and an effects module. The spatial location of the chemical stressor determines the exposure levels and ultimately the effects on the population while the relative location of the resource and organism determines growth. We develop a mathematical model, the numerical analysis for this model, and the simulation techniques necessary to solve the problem of population dynamics in an environment where heterogeneity is generated by resource and chemical stressor. In the simulations, the chemical is assumed to be a nonpolar narcotic and the individuals respond to the chemical via both physiological response and by physical movement. In the absence of a chemical stressor, simulation experiments indicate that despite a propensity to move to regions of higher resource density, organisms need not concentrate in the vicinity of high levels of resource. We focus on the dynamical variations due to advection induced by the toxicant. It is demonstrated that the relationship between resource levels and toxicant concentrations is crucial in determining persistence or extinction of the population.https://www.aimspress.com/article/doi/10.3934/mbe.2006.3.51life historyphysiologyenergeticsorganism movementtoxicologynumerical techniques.
spellingShingle Thomas G. Hallam
Qingping Deng
Simulation of structured populations in chemically stressed environments
Mathematical Biosciences and Engineering
life history
physiology
energetics
organism movement
toxicology
numerical techniques.
title Simulation of structured populations in chemically stressed environments
title_full Simulation of structured populations in chemically stressed environments
title_fullStr Simulation of structured populations in chemically stressed environments
title_full_unstemmed Simulation of structured populations in chemically stressed environments
title_short Simulation of structured populations in chemically stressed environments
title_sort simulation of structured populations in chemically stressed environments
topic life history
physiology
energetics
organism movement
toxicology
numerical techniques.
url https://www.aimspress.com/article/doi/10.3934/mbe.2006.3.51
work_keys_str_mv AT thomasghallam simulationofstructuredpopulationsinchemicallystressedenvironments
AT qingpingdeng simulationofstructuredpopulationsinchemicallystressedenvironments