Thresholds for CRITERION A – Threatened biodiversity A1. Threatened taxa: (a) Site regularly holds ≥95% of the global population of a globally Critically Endangered (CR) or an Endangered (EN) taxon; OR (b) Site regularly holds ≥0.5% of the global population AND ≥5 functional reproductive units of a globally Critically Endangered (CR) or Endangered (EN) taxon; OR (c) Site regularly holds ≥1% of the global population AND ≥10 functional reproductive units of a globally Vulnerable (VU) taxon; OR (d) Site regularly holds ≥0.1% of the global population AND ≥5 functional reproductive units of a globally Critically Endangered (CR) or Endangered (EN) taxon qualifying under Criterion A of The IUCN Red List of Threatened Species; OR (e) Site regularly holds ≥0.2% of the global population AND ≥10 functional reproductive units of a globally Vulnerable (VU) taxon qualifying under Criterion A of The IUCN Red List of Threatened Species. A2. Threatened ecosystem types: (a) Site holds ≥5% of the global extent of a globally CR or EN ecosystem type; OR (b) Site holds ≥10% of the global extent of a globally VU ecosystem type. Thresholds for CRITERION B - Geographically restricted biodiversity B1. Geographically restricted species: Site regularly holds ≥20% of the global population and ≥10 functional reproductive units of a species. B2. Centres of endemism: Site regularly holds ≥10% of the global population of a significant component of species within a vertebrate Class or non-vertebrate Order whose restricted ranges collectively define a centre of endemism. B3. Biome restricted assemblages: Sites holding the best examples of biome restricted species assemblages, in aggregate covering not more than X% of the biome area. B4: Geographically restricted ecosystem types: Site holds ≥20% of the global extent of an ecosystem type. Threshold for CRITERION C - Ecological Integrity Outstanding ecological integrity: Site is one of ≤2 sites per region of outstanding ecological integrity characterized by wholly intact species assemblages, comprising the composition and abundance of native species and their interactions. Thresholds for CRITERION D - Biological processes D1. Demographic aggregations: Site regularly or predictably holds an aggregation representing ≥1% of the global population of a species during one or more key stages of its life cycle D2. Ecological refugia: Site supports ≥20% of the global population of one or more species during periods of environmental stress D3. Source populations: Site maintains ≥20% of the global adult population of a species through production of propagules, larvae, or juveniles. Thresholds for CRITERION E - Biodiversity through quantitative analysis Sites of very high irreplaceability for the global persistence of biodiversity as identified through a comprehensively quantitative analysis of irreplaceability.This criterion is applied to species (or other relevant biodiversity elements) that can be used to trigger one or more of the other criteria (A-D): Site has a level of irreplaceability of 0.90 or higher (on a 0-1 scale), measured by quantitative spatial analysis. Sites should be characterized by the regular presence of ≥ 10 functional reproductive units of a species, or ≥ 5 units in case of geographically restricted species (sensu KBA criterion B), EN or CR species (sensu IUCN Red List). The irreplaceability analysis should be based on the contribution of individual sites to minimum representation targets defined to achieve species persistence. PROCESS 1) Expression of interest - Proposer submits expression of interest to KBA Unit to 2) 3) 4) 5) identify one or more KBAs for a region or taxa/ecosystem. KBA Unit assigns a KBA Focal Point. Proposal Development Proposer works to identify and delineate KBAs, compiling data for each site, and consulting relevant stakeholders. Process is guided by the KBA Focal Point to ensure quality submissions. Proposal (Proposed KBA) - Proposer submits KBA data online to IUCN for review. Review KBA Focal Point i) works with the proposer to ensure minimum documentation requirements are met and to make initial checks, and ii) co-ordinates input from relevant Commissions (by invitation), other relevant organisations and individuals (by invitation) and through an open forum. Continues until all issues arising are satisfactorily resolved. Nomination (Reviewed KBA) - Proposer submits revised data to IUCN as the official nomination of sites for KBA status. KBA Focal Point approves nomination online. Consistency checking IUCN KBA Unit checks for consistency of application of the Standard. Where appropriate, the KBA Committee can require an audit for the accuracy and appropriateness of information used. Endorsement (Endorsed KBA) - IUCN endorses the KBAs and publishes the data via the website with a DOI for each site nomination. Reassessment Data are compiled that may affect whether a site qualifies as a KBA: changes in knowledge or status of either the biodiversity element triggering the KBA criteria, or the site itself. Update - KBA data are updated every 8-12 years. EXECUTIVE SUMMARY In 2004 at the 3rd World Conservation Congress, held in Bangkok, Thailand, the IUCN Membership requested IUCN “to convene a worldwide consultative process to agree a methodology to enable countries to identify Key Biodiversity Areas.” In response to this Resolution (WCC 3.013), the IUCN Species Survival Commission and the IUCN World Commission on Protected Areas established a Joint Task Force on Biodiversity and Protected Areas. Over a period of three years, the Joint Task Force mobilized input from IUCN Commissions, Members, and Secretariat staff, other conservation organizations, academics, national decision-makers, donors, and the private sector to consolidate the scientific criteria and methodology for identifying Key Biodiversity Areas (KBAs) as sites that contribute significantly to the global persistence of biodiversity. The KBA Standard provides an overarching common framework to harmonize existing approaches to identify important sites for biodiversity. It builds on more than 30 years of experience in identifying sites for taxonomic-, biome-, and thematic subsets of biodiversity such as Important Bird and Biodiversity Areas, Important Plant Areas, freshwater key biodiversity areas, Alliance for Zero Extinction sites, and others. The KBA Standard also supports the identification of additional sites important for components of biodiversity not addressed by existing approaches. Because KBA identification is appropriate for biodiversity elements that benefit from safeguard or management at the site scale, some biodiversity elements, such as very wide ranging species that occur at low densities, will require complementary land- or sea-seascape approaches to ensure their global persistence. Specifically, the KBA criteria can be used to identify sites contributing significantly to the global persistence of (A) threatened biodiversity, (B) geographically restricted biodiversity, (C) ecological integrity, and (D) biological processes. Criterion (E) allows for identification of sites contributing significantly to the global persistence of biodiversity through comprehensive quantitative analysis of irreplaceability. Quantitative thresholds for each criterion have been established to ensure that KBA identification is transparent and rigorous. KBAs are delineated to achieve site boundaries that are biologically relevant yet practical for management. Delineation is an iterative process that involves assembly of spatial datasets, derivation of initial site boundaries based on biological data, refinement of the biological map to yield practical boundaries, consultation of all key stakeholders, and documenting of confidence in the site delineation. A set of required and recommended documentation is compiled for each site to support and justify the identification of a site as a KBA. This documentation also allows basic analysis of KBAs across taxonomic groups, ecosystem types and countries and helps users to search and find information easily on the website. A KBA committee, reporting to the SSC and WCPA Steering Committees, will provide the high-level strategic direction for the KBA Standard and its implementation. The committee will serve as the custodian of the scientific standards, criteria, and guidelines; establish and oversee the processes to nominate, review and endorse KBAs; develop and help oversee strategy and work program; and promote appropriate use of KBA data. KBA data should guide the strategic expansion of protected area networks by governments and civil society working toward achievement of the Aichi Targets, particularly Target 11. Because the KBA criteria align to those used to identify Ecologically and Biologically Significant Marine Areas (EBSAs; within the framework of the CBD), Ramsar sites, and natural World Heritage sites, KBAs can be considered as ‘shadow lists’ for site designation under these international conventions. KBA data can also inform private sector safeguard policies, environmental standards, and certification schemes. The potential applications and end-users of the new KBA Standard are diverse and numerous.