More Information About the Chameleon DSS

The Decision Support System (DSS) is not intended to be a definitive work on how to manage bush encroachment. The DSS was in fact developed for the Highland Savanna vegetation type of the Khomas Region, and is largely based on a conceptual model for savanna dynamics in this region, developed by Dave Joubert and Axel Rothauge (Joubert & Rothauge, 2001) and later (Joubert, Rothouge and Smit, in prep.). The model in turn was largely based on research done on the population dynamics of Acacia mellifera (swarthaak) in this vegetation type (Joubert, in prep.).

Although the DSS was developed for the Highland Savanna type, we believe it has relevance to the Thornbush Savanna, in situations where Acacia mellifera is the encroaching species. The DSS is currently only relevant to bush encroachment by Acacia mellifera (swarthaak)!. Since Dichrostachyus cinerea (sekelbos) is very different to Acacia mellifera biologically, very different management decisions might be necessary in some circumstances. Although bush encroachment is a problem in many places in Namibia, Africa and many other parts of the world, the mechanisms of bush encroachment differ from species to species and climate to climate. back to home page?

Our DSS decisions can be divided into three types:

1. Adaptive decisions: These are opportunistic decisions which would only be relevant and useful during certain circumstances related to periods of exceptionally good rainfall. Making the right decisions at these times might be crucial in preventing large-scale transitions towards bush thickets.
2. Reactive decisions: These are decisions on whether to, and how to, treat existing problems - i.e. areas already under dense cover of bush. The details of what to do under these conditions are available in the Bush Expert system developed at Potchefstroom which is currently available on the Web Site of the Namibian Agricultural Union (NAU). Our DSS thus only touches on actual methods of bush clearing.
3. Ongoing good management decisions: These decisions are based on current knowledge of normal ongoing rangeland management. We believe that if such management is maintained, the ability to manage against (prevent) transitions towards bush encroachment during rainy seasons will be greatly enhanced.

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The DSS is not designed to replace common sense decision-making based on the many years of experience of the resource manager. We believe that a DSS facilitates making the correct decisions, based on its ability to arrange knowledge (much of it already known to resource managers) in a logical order. It also helps to document the decision making process, making decision making more accountable to the decision-maker. The DSS is by no means complete. We would like to make it more flexible, incorporating, for example, decisions regarding whether a fire is feasible based on weather conditions and relations with neighbours. We would also like to incorporate more farmer knowledge into it. We would encourage a joint initiative (with our facilitation) with farmer’s who have problems with D. cinerea, and other bush encroaching species, to develop a DSS for this species. We believe that the DSS serves not only to directly improve decision-making but also to encourage debate on the topic of bush encroachment and rangeland management. We also believe that Decision Support Systems can be used for other management decisions. There is a great deal of research that is needed to refine and adjust the DSS. It is also our wish to incorporate chapters on the mechanisms of bush encroachment (as we currently believe them to be), harvesting guidelines with biodiversity considerations, and monitoring guidelines. back to home page?

Initially, the DSS was designed to be accessed on the computer (either on the web or from a CD-ROM). This is still the case but, from the feedback of a previous workshop, we decided to print a “hard copy” booklet as well. back to home page?

We thank the Polytechnic of Namibia and BIOTA for funding the development of the DSS, including the printing of the booklet. We also thank the participants of two workshops that were held in 2004 and 2005 in which the DSS was introduced and tested. back to home page?