Does the IUCN Red-Listing ‘Criteria B’ do justice for smaller aquatic plants? A case study from Sri Lankan Aponogetons

Abstract

The IUCN Red List of threatened species is recognised as the accepted standard for species global extinction risk worldwide, and the criteria led down for evaluation are considered as one of the best methods to evaluate extinction risk of species at the global and regional levels.The IUCN’s Red List categories are given more emphasis in determining the conservation status of species and for prioritizing conservation strategies upon these threatened species. The guidelines for evaluation are laid down comprehensively to minimize errors and to maintain consistency of Red List assessments across taxa. However in some cases, it seems that the assessments based on current IUCN criteria do not accurately reflect the real extinction risk of some taxonomic groups. This is not owing to the quality or quantity of the data produced, but rather to some methodological artifacts that affects certain groups of taxa. In this paper we discuss such an event considering an aquatic plant group; genus Aponogeton; from Sri Lanka. All the known Sri Lankan Aponogeton species have been evaluated under the Criteria B adhering to the given IUCN guidelines and the results suggest that such smaller aquatic plants with high habitat specificity are at a disadvantage when securing their conservation statuses, and thereby lose the protection they deserve through legislations. This study emphasises the obligation of much comprehensive evaluation criteria to estimate the AOO in different plant categories.