Abstract
All Taxa Biodiversity Inventory (ATBI) is a comprehensive inventory of all species occurring in a given territory. Its objective is to improve knowledge in taxonomy and chorology and to better understand ecological communities and their interactions within ecosystems. Wherever feasible, it should contribute to a better management of the territory through assessments and monitoring.This report, initiated by the Muséum national d’Histoire naturelle (MNHN) in Paris, presents an overview of the different initiatives worldwide and provides an assessment of the most successful ones. It is based on a consultation of more thansixty documents (i.e. scientific articles, gray literature, websites) and on interviews with dozens of experts involved in ATBI: taxonomists, task managers, technicians, data managers...This document is a first contribution towards a framework for the existing and future ATBIs in France (both mainland and overseas). An exhaustive inventory of flora, fauna and fungi in a network of reference sites is one of the recommendations for a knowledge strategy published by the MNHN and the new French Agency for Biodiversity (Touroult et al., 2017a).The first part describes the origin of the concept developed in the 1990s by North American ecologist Daniel Janzen for a project initially planned in Costa Rica (Guanacaste Conservation Area). The first ATBI was launched in 1998 in the GreatSmoky Mountains National Park (USA). With more than 19 000 species described including 940 new species, the results of this ongoing inventory exceeded all expectations and inspired a series of projects worldwide. In North America, a dozenATBIs were initiated. However, only a few projects actually inventoried a wide range of taxonomic groups. Among them were the ATBIs in Adirondack State Park (2500 species) and in the Boston Harbor Island Recreational Area (1700 species).In Europe, the first and most ambitious ATBI is the Mercantour-Alpi Marittime in the Southern Alps between France and Italy. The project started in the framework of the European Distributed Institute of Taxonomy (EDIT 2006-2011) and continueduntil 2012 thanks to the collaboration between the two Parks and the MNHN. Field activities and taxonomic research are still ongoing so the actual number of 12 000 species and 30 species new to science is expected to increase. Other EuropeanATBIs were launched by the European Distributed Institute of Taxonomy, such as the ATBI Gemer in Slovakia (3300 species), but most had limited results and none continued after 2012.In France, several ATBIs are currently been conducted: the Mercantour National Park (Southern Alps), the Lauvitel Integral Reserve of the Écrins National Park (Isère), the National Forest Nature Reserve Massane (French Catalonia), the Païoliveforest (Ardèche-Gard) and the Bois de Bouis at Vidauban (Var). Other similar initiatives as also noted are the citizen based inventory of Notre-Dame-des-Landes (Pays-de-la-Lore), the marine invertebrate’s inventory in the Guadeloupe National Park and the inventory of the Austral Islands (French Polynesia).ATBIs can also be compared to the new generation of biological expeditions such as "Our Planet Reviewed" which aims to achieve a complete species inventory in the less well-known biodiversity hotspots. Both share similar aims in terms oftaxonomic coverage and scientific scope, but ATBIs generally last longer, which allows for a better distribution of sampling effort and possible further valuations in terms of management. In addition, "Our Planet Reviewed" focuses on mega diverseareas whereas ATBIs can be conducted in a wide range of sites including close to urban areas. Other relevant initiatives, at national and regional level, are presented such as the Swedish Taxonomy Initiative and the Hawaii Biological Survey, bothof which have the objective of building a comprehensive inventory of biodiversity.The second part of the report provides a review of the key elements of an ATBI. The topics discussed are the location of the inventory, the surface area, setting up the project (objectives, duration, financing), its organization (logistics, coordination,governance), the inventory and sampling strategies, specimens management and identification, data management and dissemination and the uses and promotion of the results (i.e. for research, management and education purposes). Taxonomic impediment is often cited as one the main constraints, since many groups suffer shortage of information and available taxonomists. But other issues are addressed like the need of substantial material and financial resources, the sampling design and the importance of the human factor.