Altitudinal Zonation and Vertical Biomes

As one climbs a mountain, air temperature falls at an average environmental lapse rate of roughly 6.5°C per 1,000 meters of ascent, so that a single slope can pass through a sequence of climates comparable to a journey of thousands of kilometers toward the poles. This compression of climate into vertical bands produces altitudinal zonation, the layering of distinct vegetation and animal communities at successive elevations. The concept was founded by the Prussian naturalist Alexander von Humboldt, who, together with the French botanist Aimé Bonpland, attempted to climb the volcano Chimborazo in present-day Ecuador in 1802, reaching an estimated 5,878 meters without modern climbing equipment, then a world altitude record for Europeans. From this ascent Humboldt produced the Naturgemälde, a cross-sectional diagram correlating vegetation belts, temperature, and elevation, published in his Essai sur la géographie des plantes (1807), a work generally credited with founding the discipline of biogeography.