The Andes: The Physical Setting

The Andes are a unique topographic system that is home to the most biodiverse hotspot in the world. This unique biodiversity is the result of many interacting geological, geomorphological, climatic, and biogeographic processes that have occurred during the last 100 Ma. The origin of the Andean species is related to the recent uplift of the Andes combined with the cyclic glacial and interglacial periods favored the isolation of lowland species and as a bridge of temperate species. The climatic heterogeneity across the Andes allowed the development of several unique ecosystems from the wet Páramo in the north, to the dry Puna in the central part, and to the humid temperate forests of the Patagonia region. The combination of large-scale processes such as geology and climate with small-scale processes in Andean peaks, slopes, canyons, and valleys allows the coexistence of numerous species across an endless number of microhabitats. This unique biodiversity and the ecosystems they form offer unique contributions to people and are affected by a number of factors, including climate change and land use changes induced by anthropogenic transformation of densely occupied mountain system. These changes modify important services such as water provision and climate change mitigation while at the same time limiting the ability of the natural ecosystems and human agrosystems to protect and maintain their biodiversity.