I've been involved in ecological modelling for some 30+ years. My main interest is in the development of visual tools to support the process of constructing and running models, based on declarative modelling principles. The main such tool is Simile (http://www.simulistics.com), which is based on System Dynamics (stock-and-flow) modelling - a user-friendly notation for differential equation modelling. Simile differs from other System Dynamics tools in that it also provides a notation for expressing disaggregation in a model, similar to UML class/object/association concepts. This has potential relevance to SBML for handling complex organisational structures, e.g. grids, or populations of cells.