Resolving the paradox between species decline and regreening in the West-African Sahel : A case study from northern Burkina Faso

Abstract: After large-scale famines and decade long observations of drought, the Sahel has received a lot of attentionfrom science, politics, media and civil society. While most scientists noticed serious land degradation anddesertification in the Sahel during the 1970s and 80s, a certain “regreening” trend has been observed inrecent years. But interestingly, there is also a completely different point of view suggesting an on-goingdegradation trend in woody vegetation. Various scholars have lately observed a decline in woody speciesdiversity in the West African Sahel. This paradox has recently led some authors to challenge the observedregreening pattern, and to question if a regreening is de facto taking place.The present study verifies both the regreening and the species decline through remote sensing, localknowledge, tree inventories and size class distribution analysis. Findings suggest that a regreening has trulyoccurred during the past 20 years, whereas a small number of exotic and drought resistant species areresponsible for the observed increase in woody biomass. Around 75% of all parkland tree species aresharply declining and evidence is found that the species decline is linked to both climatic and land usechange. The regreening pattern can partly be explained through increasing rainfall during the past 20 years,but human activities equally play an important role.Findings from this study broaden the discussion about the regreening in the Sahel. Even though aregreening has occurred, the majority of socio-economic important tree species are declining. Increasingtree species are definitely less appreciated by local inhabitants. Thus, the regreening can be linked to a shiftof Ecosystem Services for local livelihoods, which deserves considerable attention in this vulnerable region.