CONF 003 XI.(b).38
Amendments to the criteria for the inclusion of natural properties in the World Heritage List and guidelines for the evaluation of nominations by IUCN
The Committee decided to instruct IUCN to use great caution in the application of criterion (iv) when it was the sole criterion for recommending sites for the World Heritage List. The sites nominated under this criterion should be habitats where "significant populations" or "concentrations of populations" of rare or endangered species of plants or animals survive, that is, sites representing in some way "superlative situations".