Abstract

The global latitudinal distribution of mountain altitudinal belts, especially alpine treelines and snowlines, has been characterized by a subtropical/dry tropical double hump with a tropical depression. The latitude or seasonal temperature has been regarded the basic driving factor, with other factors also identified of mass elevation effect (MEE), continentality, summit syndrome, and even isolation. However, MEE, defined as the temperature difference on a given elevation between the interior and outer parts of a mountain mass, has long been neglected; it actually makes temperature laps rate rather distinct from area to area, pushes treelines up to over 3,500 m above sea level or even to 4,800–4,900 m in some high mountain or plateaus, and, thus, diversifies greatly the ecological pattern of the world. The two humps on the curve of global latitudinal distribution of treelines and snowlines are in fact the result of MEE. So, its potential impact must be considered when biogeographic scenarios-based geological models are derived. The magnitude of MEE is mainly related to the intra-mountain base elevation, rather with the absolute height of mountain masses. MEE could be rather preciously modeled with intra-mountain base elevation, latitude, and hygrometric continentality for the main massive mountain ranges of the world.