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Sources, Sinks, and Model Accuracy
Citation:
ETTERSON, M. A., B. J. OLSEN, R. GREENBERG, AND W. G. SHRIVER. Sources, Sinks, and Model Accuracy. Chapter 13, Sources, Sinks, and Sustainability. Cambridge University Press, New York, NY, , 273-290, (2011).
Impact/Purpose:
Spatial demographic models are a necessary tool for understanding how to manage landscapes sustainably for animal populations. These models, therefore, must offer precise and testable predications about animal population dynamics and how animal demographic parameters respond to management actions. Here, we extend an existing Markov chain model of avian nest survival and show how the model can be used to predict seasonal fecundity by integrating multiple factors that affect avian breeding success along a latitudinal gradient. We parameterize the model with data from a marked, intensively studied population of coastal plain swamp sparrows (Melospiza georgiana nigrescens) in Delaware, USA. We also conduct a power analysis to determine the feasibility of predicting the species’ range limit using the demographic model. In general the model predictions corresponded remarkably well with the observed range limit of the subspecies. However, model uncertainty was very high, probably due to ignorance about covariances among model parameters and population regulation. Our model framework fits very well with the conceptual unification of source-sink theory, Hutchinson’s fundamental niche, and species range limits recently expounded by Pulliam (2000), though we find the realized niche to be more useful in model development and analysis.
Description:
Spatial demographic models are a necessary tool for understanding how to manage landscapes sustainably for animal populations. These models, therefore, must offer precise and testable predications about animal population dynamics and how animal demographic parameters respond to management actions. Here, we extend an existing Markov chain model of avian nest survival and show how the model can be used to predict seasonal fecundity by integrating multiple factors that affect avian breeding success along a latitudinal gradient. We parameterize the model with data from a marked, intensively studied population of coastal plain swamp sparrows (Melospiza georgiana nigrescens) in Delaware, USA. We also conduct a power analysis to determine the feasibility of predicting the species’ range limit using the demographic model. In general the model predictions corresponded remarkably well with the observed range limit of the subspecies. However, model uncertainty was very high, probably due to ignorance about covariances among model parameters and population regulation. Our model framework fits very well with the conceptual unification of source-sink theory, Hutchinson’s fundamental niche, and species range limits recently expounded by Pulliam (2000), though we find the realized niche to be more useful in model development and analysis.