title: Tree cover in Central Africa: determinants and sensitivity under contrasted scenarios of global change.
abstract: Tree cover is a key variable for ecosystem functioning, and is widely used to study tropical ecosystems. But its determinants and their relative importance are still a matter of debate, especially because most regional and global analyses have not considered the influence of agricultural practices. More information is urgently needed regarding how human practices influence vegetation structure. Here we focused in Central Africa, a region still subjected to traditional agricultural practices with a clear vegetation gradient. Using remote sensing data and global databases, we calibrated a Random Forest model to correlatively link tree cover with climatic, edaphic, fire and agricultural practices data. We showed that annual rainfall and accumulated water deficit were the main drivers of the distribution of tree cover and vegetation classes (defined by the modes of tree cover density), but agricultural practices, especially pastoralism, were also important in determining tree cover. We simulated future tree cover with our model using different scenarios of climate and land-use (agriculture and population) changes. Our simulations suggest that tree cover may respond differently regarding the type of scenarios, but land-use change was an important driver of vegetation change even able to counterbalance the effect of climate change in Central Africa.
authors.affiliation: Ecology and Evolutionary Biology, Yale University, New Haven, USA.|Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France.|UR Biens et services des écosystèmes forestiers tropicaux (CIRAD), Montpellier, France.
authors.forename: Julie C
authors.initials: JC
authors.lastname: Aleman
authors.affiliation: Département de Géographie, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Olivier
authors.initials: O
authors.lastname: Blarquez
authors.affiliation: UR Biens et services des écosystèmes forestiers tropicaux (CIRAD), Montpellier, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Gourlet-Fleury
authors.affiliation: Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bremond
authors.affiliation: Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France.
authors.forename: Charly
authors.initials: C
authors.lastname: Favier
mesh_terms: D000350:Africa, Central; D002138:Calibration; D057231:Climate Change; D003198:Computer Simulation; D005843:Geography; D014197:Trees / Q000502:physiology*