NATURE-RESERVE SELECTION IN THE TRANSVAAL, SOUTH-AFRICA - WHAT DATA SHOULD WE BE USING

Iterative reserve selection algorithms were applied to two mammal data bases, generalized to sixteenth degree grid squares, for the Transvaal region of South Africa. Based on primary point data, 24 grid squares are required to represent all species at least once, while only 13 gri d squares are required when based on distribution map data; only two o f these grid squares are common to both analyses. As the number of rep resentations per species is increased from one to five, the number of selected grid squares increased to 86 and 71 or 72 respectively, with only 17 of these common to both analyses. These differences in the sel ection of sites are further reflected in the degree of congruence betw een selected grid squares and existing conservation areas which is on average 63.3% for grid squares selected from the primary database and only 42.5% for those selected from the distribution map database. Thes e results emphasize the importance of quality data input when evaluati ng regional reserve networks. Highly generalized distribution map data sets, on the one hand, are extrapolations of limited data sets and co ntain non-quantifiable levels of false-positives which could have sign ificant implications if used for establishing regional reserve network s. On the other hand, although there are problems associated with the establishment of primary diversity databases, namely data currency and uneven and non-random sampling (leading to false negatives), they rem ain our most reliable option for assigning conservation value.