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Abstract

Sensitivity and uncertainty are intrinsic properties of ecological models, and their characterization is an
important step in the modelling process. We use a spatially explicit multi-scale model of a coral reef
system to explore four aspects of model sensitivity and uncertainty: (i) sensitivity to initial conditions;
(ii) sensitivity to parameter values; (iii) sensitivity to spatio-temporal resolution; and (iv) the effects
of uncertainty about spatio-temporal variability of ecological processes on the shape of distributions of
model predictions. We use reef community composition, visualized in multivariate space, as a response
variable. This approach provides an easily interpretable representation of changes in reef community
composition under different parameter conditions and spatio-temporal resolutions. It is also a useful
means to visualize distributions of model outcomes under differing assumptions about the nature of
variability in ecological processes in the real world. Our results indicate that reef state and recovery
trajectories are particularly sensitive to parameters determining coral growth and mortality rates. Variability
in model outcomes depends on assumptions about the way parameters vary in space and time,
and is greater at local scales than at subregional and regional scales. We highlight the fact that predictions
based on the kind of model presented here are likely to be more robust for subregions and regions than
for particular reef localities.

Item Type:	Article
Authors/Creators:	Melbourne-Thomas, J and Johnson, CR and Fulton, EA
Keywords:	Coral reefs Ecosystem model Spatially explicit Sensitivity Uncertainty
Journal or Publication Title:	Ecological Modelling
ISSN:	0304-3800
DOI / ID Number:	10.1016/j.ecolmodel.2011.07.014
Additional Information:	Copyright 2011 Elsevier
Related URLs:	http://dx.doi.org/10.1016/j.ecolmodel.2011.07.014
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