The differences explained
The 1997 IUCN Red List of Threatened Plants and the 2006 IUCN Red List of Threatened Species are both available on-line as searchable databases.
The two databases both provide information on species of conservation concern, but differ greatly in content.
Number of Threatened Plant Species
The 2006 IUCN Red List of Threatened Species contains information on 8,390 plant species
The 1997 IUCN Red List of Threatened Plants contains information on 33,798 plant species
Original and New IUCN Standards
These figures for the number of globally threatened plants differ greatly, as a result of the process involved in assessing a species for threat status.
- The 1997 list is based on the “original” IUCN standard for assessing threat status, which had been in use since the IUCN Red List system was first developed in the early 1960s. National threat status is recorded from a variety of sources and the global status is assigned based on this information.
- In 1994, IUCN published a “new” revised standard for assessing threat status. It is not possible to simply convert categories defined under the original system to the new system.
- The new system is much more precise than the original system as more information is required about a species prior to a category being assigned. However, the processes of gathering the required information and agreeing the categories take time. Consequently, fewer species have been assessed under the new categories.
- Until all species included in the 1997 list have been assessed according to the new standard, the 1997 list provides the best source of information on these plants. Once all these species have been assessed, the 1997 list will continue to provide a historical record of the status of information at the time.
How to use the 1997 and 2006 Lists
Users are therefore recommended, in the first instance, to search the 2006 list for data, and subsequently to search the 1997 list, if the species was not found in the 2006 list, or if historical data are of interest.