Tools for valuation assessments
Tools for valuation assessments that were used in the past vary in information content, scientific rigour, and the level of technology used.
- The most simple approach is low-tech participatory planning, which often occurs in community-based marine protected area (MPA) design (e.g. the Mafia Island Marine Park Plan, described in Agardy 1997), but the selection of such priority areas is very ad-hoc, opportunistic, or even arbitrary, resulting in decisions which are often difficult to defend to the public. The chance of selecting the areas with the highest intrinsic biological and ecological value through these methods is small.
- Later on, a more Delphic-judgmental approach has been advocated. In this approach, an expert panel is consulted to select areas for protection, based on expert knowledge. The method is relatively straightforward and easily explained, which may indicate why it is still common. However, owing to the urgency for site selection, the consultation process is usually too short, the uncertainty surrounding decisions is too high, and the information input is too generalized to permit defensible, long-term recommendations.
The disadvantages of these aforementioned existing methods for assessing the value of marine areas have led to an increasing awareness that a more objective valuation procedure is needed.
- Other existing methodologies utilize a variety of tools to optimize site selection through spatial analysis, such as Geographic Information System (GIS)-based multicriteria evaluation.
- The most sophisticated methods are those where planning is driven in part by high-tech decision-support tools. One such tool is MARXAN, which is a systematic conservation planning software program used to identify reserve designs that maximize the number of species or communities contained within a designated level of representation. The methodology behind this approach is described by Possingham et al. (2000), and it has been incorporated into various planning efforts. This technique is mostly used for reserve selection and uses mathematical models to select those subzones which contribute most to the specified conservation goals established for the system while minimizing the costs for conservation.
Without denying the merits of MARXAN and similar mathematical tools for conservation planning, this technique cannot be applied for the purpose of biological valuation of an area. Biological valuation is not a process to select areas for conservation according to quantitative objectives, but gives an overview of the integrated biological value of the different subzones within a study area (relative to each other). The decision to include one or more subzones in a marine reserve cannot be made on the basis of the outcome of a biological valuation, because the latter process does not take into account management criteria and quantitative conservation targets.
- Possingham H.P., Ball I.R., Andelman S. (2000). Mathematical methods for identifying representative reserve networks. In: Quantitative methods for consrevation biology, S. Ferson & M. Burgman (eds.), Springer-Verlag, New York, 291-305.