DEALING WITH ESTABLISHED RESERVE NETWORKS AND INCOMPLETE DISTRIBUTIONDATA SETS IN CONSERVATION PLANNING

An iterative reserve selection algorithm is used to address real-world constraints which affect our ability to achieve regional biodiversity representativeness when using the principle of complementarity Two ke y constraints in representative reserve selection procedures are addre ssed: incomplete data sets and established reserve networks. In the fi rst instance, a geographic information system (GIS) is implemented to interpolate the observed biodiversity data and derive data for unsurve yed 15' x 15' grid cells from neighbouring grid cells. Conservative in terpolation increased the number of data records by 8%, whereas the le ss conservative interpolation led to a 260% increase in the number of data records. Site selections based on the less conservative interpola tion appears more efficient, but this greater efficiency may come at a price, namely, of not truly representing all species on the ground. S uch interpolated data sets should thus be ground-truthed with further field surveys before using them for definitive conservation planning. Secondly, the established reserve network is shown to make an ineffect ive contribution to regional representation of mammalian species. The preselection of existing reserves has the effect of increasing the lan d area required for full species representation. Large ad hoc reserve networks can therefore increase the cost of achieving representative s ystems. The effect of the systematic alteration of (1) pre-selection c riteria, (2) degree of data interpolation and (3) selection rules used by the algorithm on evaluating alternative reserve network configurat ions is discussed and forms the basis of a 'relative algorithm-specifi c index' (RASI) for identifying frequently selected sites. This can be used in land-use planning exercises to evaluate trade-offs between co nservation, agriculture and development.