IUCN

For more than thirty years, the Species Survival Commission (SSC) has been assessing the conservation status of species and subspecies on a global scale in order to highlight taxa threatened with extinction, and therefore promote their conservation. Although today we are operating in a very different political, economic, social, and ecological world from that of the first IUCN Red Data Book, the SSC remains firmly committed to providing the world with the most objective, scientifically-based information on the current status of globally threatened biodiversity. As species and subspecies are the bearers of genetic diversity and the building blocks of ecosystems, information on their conservation status and distribution provides the foundation for making informed decisions about preserving biodiversity at local to global levels.

We have introduced several innovations which have enhanced the effectiveness of the 1996 IUCN Red List as a conservation tool:

At the species level, the conservation status of all vertebrates and the majority of invertebrates listed in the 1994 Red List has been re-assessed;
For the first time, all mammal species have been assessed, in addition to many other species that had not previously been evaluated;
We have adopted and applied a more objective system for classifying conservation status, that allows comparisons to be made across species in assessing likelihood of extinction;
The information is presented in a more user-friendly manner so that it may be used by a much larger and varied audience; and
We have tried to make the information more accessible as it is posted on the World Wide Web, with links to other threatened biodiversity information sources.

With the help of a network of more than 6,000 SSC Specialist Group members, and data from BirdLife International, the World Conservation Monitoring Centre, and The Nature Conservancy, the 1996 IUCN Red List of Threatened Animals is the most comprehensive inventory ever of threatened species and subspecies on a global scale. The efforts of the large network of volunteers and partner organizations have resulted in the recognition of the 5,205 threatened taxa listed in this book.

The conservation status of every mammal species in the world is assessed for the first time in the 1996 IUCN Red List. The only other major taxonomic group that has been comprehensively evaluated is birds (Collar et al. 1994). Assessing every species in these taxonomic groups represents a major milestone in conservation, enabling us to determine clearly the overall status of mammals and birds, and to continue to monitor the trends within these higher-taxon groups. Although determining the conservation status of all birds and mammals is a great step forward in conservation, these two classes represent about 30% of vertebrates and only 0.8% of all named species. Within the next five to ten years, we hope to have all known higher vertebrates and freshwater fishes completely assessed. Unfortunately, given lack of financial resources, and the sheer magnitude of the numbers of lower vertebrate and invertebrate species, it will probably be a long time before these taxa receive comprehensive conservation assessments. Furthermore, there are currently about 1.5 to 1.8 million named species, but it is estimated that the actual number of species in the world ranges from 5 to 10 million (May et al. 1995). If this prediction is correct, then thousands to millions of species may be missing from the Red List because they have not yet been discovered or described. Nevertheless, despite these difficulties, the number of invertebrate and fish species included within the Red List has risen sharply in the last three published editions.

To improve the quality and usefulness of the information in the Red List, we have used the new IUCN categories and criteria, approved by IUCN Council in 1994. This system improves the objectivity of the listing process by providing quantitative criteria that define each category of threat (Critically Endangered, Endangered, and Vulnerable). It also requires specialists who provide assessments to give a reason for the listing of each species or subspecies in a particular threat category. Providing specific reasons for listing: (1) improves the accountability of the system; (2) provides information that may lend insight into processes driving extinction for a specific species, taxonomic groups, or taxa in a particular region; and (3) provides the basis for systematically monitoring changes in status over time. Details of the new system can be found in the section entitled The New IUCN Categories and Criteria, and also in Annex 2 at the end of this publication.

The Red List was traditionally written for a scientific audience (Scott et al. 1987), but as the imperiled status of biological diversity has become increasingly evident, the general public and policy makers have taken a much stronger interest in the growing list of threatened taxa. We have changed the format of the publication to appeal to a much wider audience while retaining scientific content. Where possible, common names have been included for all species and subspecies.

The 1996 IUCN Red List of Threatened Animals is now on the World Wide Web at (http://www.wcmc. org.uk/data/database/rl_anml_combo .html). This allows any person with Web access to use the database to obtain information such as:

Currently, links are being developed to allow direct access to relevant SSC Specialist Group Action Plans or Specialist Group home pages. IUCN will be developing Web connections between the Red List and other biodiversity information sources. This will enhance the value of the Red List as a starting point for exploration of conservation options, ranging from the genetic to the ecosystem level.