Addressing Uncertainty in Marine Ecosystems Modelling

Abstract

Ecosystem modelling has become a very important way to study marine ecosystems processes. A valuable tool for model development is the use of the software package Ecopath with Ecosim , which enables the construction of foodwebs and their simulation over time and space according to different scenarios. An important part of the process of ecosystem modelling is to compare results from the model with those from observations, followed by an analysis of the remaining sources of error. However, few of the currently developed Ecopath models have gone so far as to examine the uncertainty in analyses. Thus, it would be useful to address this problem, to clearly define the type of uncertainty that may be encountered in ecosystem modelling, and the means by which it may handled. Sensitivity analyses represent one solution by which one might address uncertainty in Ecopath with Ecosim . This approach functions by examining the sensitive elements as revealed in model results with differing scenarios of model-building and construction. In addition, other tools can also be used to perform uncertainty analysis routines. Examples are the Pedigree, Ecoranger and Autobalance tools, all of which are included the Ecopath software package. Furthermore, it is possible to combine these approaches with other modelling techniques in order to get an even stronger analysis of uncertainty. The purpose of this paper is to examine the strengths and weaknesses of these different approaches in addressing uncertainty.