Résumé
The High Conservation Value (HCV) concept, developed by the Forest Stewardship Council to promote sustainable forest management, is widely employed for certification of forestry and agriculture concessions, and has been adopted by many logging and palm oil companies. HCV criterion 1, which deals with “endemic, and rare, threatened or endangered species”, is rarely used in certification, mainly because lists of these species are incomplete, especially for plants, and performing threat assessments is time-consuming. The IUCN Red List Categories are often suggested as a suitable basis to define threatened taxa for the application of HCV1, but this requires the rapid and efficient assessment of large numbers of species. Using the plants endemic to Gabon as a case study, we propose a rapid, two-step procedure to identify HCV1 species. First, based on 3,298 verified and geo-referenced herbarium records, we used GIS layers and an automated computational workflow in the R environment to identify potentially threatened species using an approach aligned with IUCN Red List criteria A, B, and D. Ninety percent of the automated assessments correctly indicated the risk of extinction; errors involved incorrect assessments of species whose habitat is in reality not threatened, or occurred during the calculation of the number of locations (sensu IUCN) when a single threat impacts large areas. In a second step designed to correct these issues and comply with the Red List guidelines, we performed species-by-species verification of the automated assessments, taking into account the ecology and habitat of each species and the nature of the threats it faces. Of the 389 endemic taxa analyzed, 86 % were identified as threatened (83 CR, 171 EN, and 80 VU); of these, only 35 % are recorded from at least one National Park, but most are found in logging/oil palm (72 %) or mining (55 %) concessions, underscoring the need to improve the application of the HCV concept. To strengthen the use of HVC subcriterion 1.2 (rare, threatened or endangered species), we propose an explicit method for identifying rare species based on a quantitative threshold of the Extent of Occurrence (20,000 km²), and we examine the concept of endemicity with respect to the application of HVC subcriterion 1.3 (endemic species). The proposed methodology addresses an urgent need to develop a national interpretation of the HCV concept in Gabon, adopted as a national standard for logging concessions, and offers an efficient, reliable approach for the application of HVC1 elsewhere in Central Africa.