Biodiversity gap analysis of the protected area system in poorly-documented Chad

Chad is amongst the richest countries in terms of biodiversity in Sahelo-Sudanian Africa with some of the last remaining populations of large mammals that once roamed West-Central Africa. Its protected area (PA) system, made up of three national parks (NP) and seven faunal reserves (FR) and introduced 40 years ago to focus on the protection of large game, has never been reviewed in terms of biodiversity coverage. This study (i) assesses whether the PA network captures Chad's current biodiversity (focusing on ecoregions and threatened mammal species), (ii) identifies gaps in the PA system and (iii) proposes recommendations to improve the representativeness of the PA system, in a country characterised by the lack of biological data. Of the seven ecoregions in Chad, three are not covered by PAs and two are represented only once and have less than 10% of their area included in the PA network. Of the 31 large mammal species used in the analysis, five occur only once in the network and five species are not represented. Analysis of the persistence of species shows that, of the nine historical PAs, all have lost at least one (and up to six) species of large mammals. The Ouadi Rimé-Ouadi Achim FR was found to have the highest irreplaceability index, with the Bahr Salamat FR and Zakouma NP second and third respectively. Zakouma NP has the highest number of large mammal populations of an internationally important size. Threatened large mammals, many depending on large-scale migration, and (migratory) waterbird populations highlight the lack of wetlands in the formal PA system. We recommend a more effective protection of these wetlands, an extension of the PA system into ecoregions not covered by current PAs and provide details on the realignment of several of the PAs that have been encroached upon and are no longer viable.