ABSTRACT
The subspecies classification of Rangifer has been dominated by a high number of described subspecies without well-defined subspecific characteristics. Genetic diversity has key ecological consequences for populations, communities and ecosystems, because it provides the basis for phenotypic plasticity, local adaptation or the ability to evolve in response to changing environmental conditions. Human-reindeer history goes back to the Paleolithic period and involves hunting of wild reindeer as well as later keeping tamed reindeer for transportation, clothing and food. The most productive semi-domestic herds occur in the tundra Nenets regions of northwest Russia straddling the Ural Mountains. Caribou in North America have adapted to tundra, montane and boreal forest habitats in a variety of ways, with seasonal movements, group sizes and seasonal ecology shaped in various ways by their main predator, the wolf and by weather and habitat characteristics. In North America, the big tundra migratory caribou herds typically experience substantial fluctuations in population size.
