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68 12. Conclusions There are several main conclusions. First, if the ecosystem modelling community operated within a declarative modelling paradigm, projects such as ATEAM would be radically transformed. Activities that currently involve weeks or months or programming effort (such as downloading and running existing models) could - literally - be undertaken with a few mouse clicks. Modifying existing models or building new ones would be much simpler. And stakeholders could be involved in the modelling process. Second, this is not some hand-waving, "wouldn't-it-be-nice-if" speculation. Everything outlined here is easily feasible - even routine - with today's technology. All that is required is the will with the ecosystem research community to make it happen, some core funding to produce the standards and basic tools, and some investment in translating a representative set of models into a declarative representation. Third, the approach is very flexible. Models can be stored on your own computer, published on the web, or held in a web-accessible database. Tools can be developed independently, in any language. There is no forced commitment to rigid interfaces for modules. Fourth, a declarative modelling approach is an example of 'sustainable technology'. In the 70's, people were suggesting a Fortran-base modelling framework; then it was object-oriented modelling in C++; now it is Microsoft's COM technology. Programming-based standards will change, with resulting obsolescence for the intellectual investment in models implemented according to the prevailing standard. Declarative modelling represents a specific commitment to the concept of transforming models: for display, or for generating a runnable version. If standards change - if a new language becomes the standard - then the existing pool of models can be readily preserved by translating them into the new language. Finally, declarative modelling is at the very start of its growth curve. Its most significant feature is that we don't yet know what its most significant features will be! As with HTML, so with declarative modelling. New ideas will emerge about what we can do with models, and tools implementing these ideas. Representing model structure in a 3D virtual reality (VR) system, and navigating around it using immersive VR? Use Enhanced (or Augmented) Reality technology, so that one can see the relevant part of the model structure while moving around a landscape? Develop expert systems, containing ecosystem knowledge and modelling knowledge, to help researchers design models? Automatic model simplification? Automatic generation of a narrative, based partly on model structure and partly on simulation output, to explain model behaviour? The pebble has dropped into the pond, but the ripples will through up new and fascinating patterns for many years to come.
69 Acknowledgements and declaration of interest This paper was written, and some of the work described herein was undertaken, while I was on a Darwin Trust of Edinburgh Research Fellowship. I cannot adequately express my appreciation to the Trust for its support: most academics can only dream of having 3 years to pursue Ideas, with no teaching, administration - or even reports to write. I'm now an 'independent academic' (that's another name for a house husband): thanks to Marion for carrying on working while I play on my computer. The development of Simile has been mainly funded by the United Kingdom Department for International Development (DFID) for the benefit of developing countries The views expressed are not necessarily those of DFID. Project codes were R5652 and R7635 Forestry Research Programme. Some development has also been funded by the EU Environment Programme, within the ModMED project I gratefully acknowledge the support received from these sources. In November 2001, a startup company, Simulistics Ltd, was formed under licence from the University of Edinburgh and with the approval of the DFID/FRP Programme Manager to develop and market Simile and related products and services. I am a minority share-holder in this company. Jasper Taylor wrote the original Simile software - many thanks to him for turning an idea into reality. I am grateful to the ATEAM project for inviting me to be an external assessor, and for giving me the opportunity to learn so much about such an ambitious and wide-ranging project. Parts of Section 9 were based on internal ATEAM publications and discussions with ATEAM members. I would also like to thank Denis Peter (Programme Officer, European Commission - DG Research: Environment and Sustainable Development Programme), whose idea this paper was, and the ATEAM and AVEC projects for supporting its preparation. I also acknowledge the detailed feedback provided by Rik Leemans on an earlier draft, and corrections on the nature of the ATEAM project from Dagmar Schröter. I have appreciated useful discussions with Jonathan Massheder and Alastair Davies (Simulistics), members of the MODCOM group, and many others on the subject of declarative modelling. For some reason, most people seem to disagree with me, but that has no doubt helped to hone (and moderate) my ideas.
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