Alliance for Zero Extinction (AZE) sites contain the entire population of one or more species listed as Endangered or Critically Endangered on the IUCN Red List of Threatened Species. The Alliance itself is formed of 93 biodiversity conservation institutions from 37 countries, and its goal is to prevent the extinction of species. Following identification, the Alliance aims to act together to eliminate threats and restore habitat at these sites to allow species populations to rebound. The focus of AZEs is on species that face extinction either because their last remaining habitat is being degraded at a local level, or because their restricted global range makes them especially vulnerable to external threats.
AZEs are included under the 'umbrella' classification of Key Biodiversity Areas (KBAs).

The Alliance for Zero Extinction – a joint initiative of 93 non-governmental biodiversity conservation organizations from 37 countries around the world, with frequent additions of new members. The Alliance for Zero Extinction also collaborates with over 100 national institutions.

Formed in 2000 and launched globally in 2005. Identification of AZEs is an ongoing process, as part of the overall process of identification and subsequent conservation actions in KBAs.

Global in extent, with 595 identified site-scale areas, where 794 endangered species reside (2010 data) ¹.The AZE list is regularly updated to include new sites and species.

There are three criteria to identify AZE sites ²:

1. Endangerment: Must contain at least one Endangered or Critically Endangered species, as listed on the IUCN Red List of Threatened Species. A site cannot be designated on the basis of unlisted or unevaluated species, Data Deficient species, or Vulnerable species. A site may be designated as the only suitable reintroduction site for a species assessed as Extinct in the Wild; only two sites were triggered by this criterion.
2. Irreplaceability: Must (i) be the sole area where an Endangered or Critically Endangered species occurs, (ii) contain the overwhelmingly significant known resident population of the species (more than 95% of the global population), or (iii) contain the overwhelmingly significant known population for one life-history segment (e.g., breeding or non-breeding) of the species.
3. Discreteness: Must have a definable boundary, within which habitats, biological communities, or management issues share more in common with each other than they do with those in adjacent areas (e.g., a single lake, mountaintop, or forest fragment). The boundary of each area is based on the most practical conservation unit, including considerations of contiguous habitat, management units, and the potential for significant gene flow among populations. There is no explicit size criterion for sites, but the median size of sites for which size information is available is 12,060 hectares.

There is no management prescribed for AZE sites. Globally, about 23% of AZE sites are covered by protected areas. ³ The management of such sites varies according to the type of protected area they are part of. Due to their small size, these sites are highly susceptible to human activities in the surrounding landscape. The mean human footprint, an aggregate index of human land use, human population and infrastructure at AZE sites is two and a half times the global mean, indicating a high level of threat. ³

Legal and compliance – Identification of an area as an AZE site does not automatically lead to legal protection or recognition by national government. However, in some cases these sites are located within existing protected areas, or indeed lead to the designation of additional protected areas, and therefore afforded legal protection. AZEs are not usually included by name in standards and certification schemes, but these typically include requirements relating more broadly to the umbrella concept of KBAs which encompasses AZEs. For examples of standards and certification schemes which refer to KBAs, please visit the KBA factsheet.

A Memorandum of Cooperation was signed between the Secretariat of the Convention on Biological Diversity (CBD) and the Alliance on May 19th, 2010. Under this Memorandum, nations should account for their progress protecting AZE sites and species in their National Biodiversity Strategies and Action Plans. In Japan, during the 10th Conference of the Parties of the Convention in 2010, the GEF and World Bank announced an initiative to promote AZEs globally.

Biodiversity importance – AZE sites are of very high biodiversity importance as they are identified based on the criteria of both high vulnerability and high irreplaceability of species. 81% of AZE sites occur within biodiversity hotspots, which further indicates their biodiversity significance. ³ Their main aim is to prevent extinctions by identifying and safeguarding key sites where species are in imminent danger of disappearing. AZE sites are identified at the site-scale based on existing protected areas, concessions and management units, and are therefore of high relevance for mitigating and avoiding risk from biodiversity loss and identifying opportunities to be associated with conservation activities.

Social and cultural values – The AZE sites are not identified based on recognition of any traditional practices, cultural values, rights or involvement of local/indigenous communities in protection, use and management. However, a recent study by Conservation International (CI) and NatureServe suggests that conservation of AZEs yields parallel benefits to people in terms of ecosystem services, such as climate change mitigation, freshwater services, retention of biodiversity for future use and cultural value. ⁴