Uncertainty in spatially explicit animal dispersal models

Ecological Applications
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Abstract

Uncertainty in estimates of survival of dispersing animals is a vexing difficulty in conservation biology. The current notion is that this uncertainty decreases the usefulness of spatially explicit population models in particular. We examined this problem by comparing dispersal models of three levels of complexity: (1) an event-based binomial model that considers only the occurrence of mortality or arrival, (2) a temporally explicit exponential model that employs mortality and arrival rates, and (3) a spatially explicit grid-walk model that simulates the movement of animals through an artificial landscape. Each model was fitted to the same set of field data. A first objective of the paper is to illustrate how the maximum-likelihood method can be used in all three cases to estimate the means and confidence limits for the relevant model parameters, given a particular set of data on dispersal survival. Using this framework we show that the structure of the uncertainty for all three models is strikingly similar. In fact, the results of our unified approach imply that spatially explicit dispersal models, which take advantage of information on landscape details, suffer less from uncertainly than do simpler models. Moreover, we show that the proposed strategy of model development safeguards one from error propagation in these more complex models. Finally, our approach shows that all models related to animal dispersal, ranging from simple to complex, can be related in a hierarchical fashion, so that the various approaches to modeling such dispersal can be viewed from a unified perspective.


Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Uncertainty in spatially explicit animal dispersal models
Series title Ecological Applications
DOI 10.1890/1051-0761(2003)013[0794:UISEAD]2.0.CO;2
Volume 13
Issue 3
Year Published 2003
Language English
Publisher Ecological Society of America
Contributing office(s) Southeast Ecological Science Center
Description 12 p.
First page 794
Last page 805
Online Only (Y/N) N
Additional Online Files (Y/N) N