Deux systèmes d’évaluation du statut de conservation des espèces en France : complémentarité ou redondance ? Cas de la Liste rouge et du rapport sur l’état de conservation pour la directive Habitats-faune-flore

Abstract

Two systems to assess species conservation status in France : complementarity or redundancy ? The case of the Red List and of the Habitats Directive report on species conservation status.— The Red List of threatened species initiative and Member State reporting under the European "Nature" Directives both provide regular assessments of species conservation status at a national level. Focusing on Habitats Directive species within metropolitan France, this study investigates complementarity and redundancy of both assessment systems. In terms of concepts and classification, the two approaches cover both ends of the conservation status “gradient” (from extinction to favourable conservation status). The national Red List is an alert and monitoring system which measures the risk of extinction for each species within a given taxonomic group. The Habitats Directive assessment measures the gap between current status and “favourable status” for 312 species and subspecies. Despite their different spatial scales (administrative vs biogeographical boundaries), the two assessment systems are broadly similar in terms of methods, organization, data and experts involved. For example, for the studied groups, half of the 140 experts mobilized for the national Red List initiative also contributed to the latest assessment of Habitats Directive species in France. Our study compares the conservation status of over 140 taxa assessed by both methods. The results show a strong consistency between the two systems (63 % of cases), especially for extreme status categories. However, our analysis also highlights conceptual and methodological differences, mainly regarding the definition of thresholds and the concept of favourable reference values. Given limited data and restricted human resources, we suggest several ways to promote their convergence. For example, the mutual comparison of assessments results during the validation phase could provide useful information about inconsistencies ; moreover, the two assessments processes could be synchronized in order to gather expert advice and data more efficiently.