Risks associated with the setting of conservation priorities from rare plant species lists

The process of listing rare and endangered species serves a number of practical purposes in conservation, but the difficulties of defining rarity and of comprehensively documenting plant distributions can lead to bias in the lists. An analysis of the flora of north-eastern New South Wales and of the rare or threatened plants (ROTAP) occurring in the region (using an IUCN-based classification) reveals that the list is dominated by species of restricted range and/or habitat. The criteria by which taxa are listed may favour the inclusion of these plants over species with widespread but declining ranges. The proportion of herbaceous species and of sparse species (wide geographic ranges and broad habitat requirements) in the ROTAP list is low. Circumstantial evidence suggests that the proportion of plants at risk in these two categories may be under-estimated due to inadequate information. Because rare plant listings can be used to determine conservation priorities, their potential biases need to be recognized.