PALEOECOLOGICAL IMPLICATIONS OF PLANT/ANIMAL GRAZING RELATIONS ON THE MAMMOTH STEPPE OF EASTERN BERINGIA

This paper reassesses the areal extent of Mammoth Steppe in Eastern Beringia and discusses some of the ways in which grazing and topography entered into the maintenance of the Mammoth Steppe. Large, generalist grazing mammals, by their grazing style, helped maintain the Mammoth Steppe by removing old-growth and by stimulating grass plants to reproduce vegetatively. These grazers also promoted uniformity in growth-form and uniformity in plant biomass (phytomass) above and below the ground surface. During the late Pleistocene these large, generalist grazers were eliminated from interior Alaska by Paleolndian hunters and their predatory animal companions. The loss of these large, generalist grazers precipitated a change in the structure of the Mammoth Steppe grassland and this eventually led to the replacement of steppe grassland by herb tundra