Floods and droughts : Stable isotope compositions of plants to improve climate reconstruction in the semi-arid environment of Northern Botswana and the Zambezi region of Namibia

Northern Botswana and Namibia present semi-arid environment, where evaporation exceeds precipitation, interlaced by major river systems including the Zambezi, Kwando, and Okavango rivers. Water availability is the principal constraint on human livelihoods, ecosystems, and economic activities, with these rivers serving as critical resources for agriculture, domestic supply, fisheries, and tourism. Recent shifts in precipitation regimes are altering regional hydrological systems and affecting both ecosystems and water-dependent communities.
In southern Africa, where climatic records are scarce, isotopic dendrochronology provides a valuable proxy for reconstructing recent water availability and water sources changes. This on going study employs combined dendrochronological and isotopic analyses of two endemic tropical tree species, Baikiaea plurijuga and Colophospermum mopane, to develop regional chronologies and improve reconstructions of past climatic conditions, thereby enabling better assessment of recent changes in water regimes.