Ten years of research on the biodiversity of the Great Green Wall by the International Human-Environment observatory Téssékéré in Senegal

The Sahel has long been plagued by drought, which along with human pressure has caused ecosystem degradation, biodiversity loss, and increased poverty of local populations. Thus, in 2005 African heads of state set up a project, named the “Great Green Wall” (GGW), to restore Sahelian ecosystems. Establishment of the GGW led to the founding in 2009 of the “International Human-Environment observatory Téssékéré (OHMi Téssékéré)”, between France’s National Center for Scientific Research and Cheikh Anta Diop University (Dakar, Senegal), to assist decision-making by providing scientific information. The OHMi’s research is conducted in the Ferlo, northern Senegal. This paper summarizes knowledge of the region’s biodiversity and how the GGW may affect it. Semi-natural grazed parklands dominated by grasses with scattered trees occupy over 90% of the surface. Eighty-two woody plant species, representing 55 genera and 26 families, have been recorded. Forbs (non-graminoid herbs) are more diverse but account for a small proportion of vegetation cover. The study of arthropod biodiversity is just beginning. A first study showed that 427 insect morpho-species visit the flowers of a single common tree species, Balanites aegyptiaca . Vertebrate biodiversity includes seven species of amphibians, eleven species of reptiles and 217 bird species, among them palearctic migratory species (including 60 waterbirds) some of which are classified at high protection levels on the IUCN’s Red List. Four species of micromammals (in order of decreasing abundance, Gerbillus nigeriae , Arvicanthis niloticus , Taterillus pygargus and Mastomys erythroleucus ) occur in the area. Nine species of large wild mammals occur, of which eight are nocturnal.