Risk assessment of the impact of future land use and future climate change on the distribution and diversity patterns of plant species used for nutrition (Burkina Faso)

Land use and climate changes predicted for the 21rst century pose high risks for ecosystems and the services they provide. They represent also serious hazards for plant biodiversity. The rural population is especially vulnerable as their livelihoods depend extremely on natural products derived from plant species. In West Africa a gradient of plant diversity is found which is mainly determined by the bioclimatic gradient (Linder 2001). Plant species diversity increases gradually from the southern parts of the Sahara to the Gulf of Guinea. Future changes in temperature and precipitation amounts as well as the increase of extreme weather events are expected to impact plant diversity considerably. Besides climate human activities in form of agriculture, grazing, fire and harvesting of plant parts have an important effect on plant diversity. The traditional shifting cultivation system (slash and burn) is more and more replaced by clearing and pesticide-intensive cash-crop cultivation (Augusseau et al. 2006) leading to still indeterminable impacts for plant biodiversity. Annual population growth in West African countries is around 3%. Some authors even consider land use change as more threatening to plant diversity than climate change (Sala et al. 2000). Up to now there are just very few studies investigating the impact of future climate on plant diversity in Afrika (Da 2010) and even less that take into account the risks that land use imply (Luoto et al. 2007; de Chazal & Rounsevell 2009). The main problems are missing reliable land use simulations for the future. Heubes et al. (2013) took climate and land use changes into account to predict plant diversity in Burkina Faso. They found that plant diversity will be impacted mainly negatively by future land use and climate changes. This study aims to undertake a profound assessment of the risks that land use and climate change pose to plant diversity of species that are used by the local population for nutrition purposes. Considered are highly valued nutrition species under the impact of climate and land use changes by 2050.