ABORIGINAL OVERKILL AND THE BIOGEOGRAPHY OF MOOSE IN WESTERN NORTH AMERICA

Abstract

At historical contact, moose (Alces alces) were rare or absent throughout much of western North America but since ca. 1990 moose have increased dramatically. Several hypotheses have been advanced to explain the historical distribution and recent spread of moose in western North America. These include, (1) European settlement modified the original climax forests, which were poor moose habitat, and created seral vegetation types moose prefer. (2) Predators such as wolves (Canis lupus) once limited moose but near the extermination of native carnivores allowed moose to extend their range. (3) Moose has insufficient time to colonize the areas since the last glaciation. (4) Climatic variation -- the Little Ice Age and associated severe winter weather limited moose populations ca. 1700-1880. And (5) disease once limited moose numbers. None of these hypotheses, though, is supported by the available evidence. Instead, I propose that moose biogeography was controlled primarily by native hunting. An Aboriginal Overkill hypothesis is presented and discussed. That analysis indicates that moose were extremely vulnerable to predation by Native Americans and that native peoples had no effective conservation practices. Native Americans were the ultimate keystone predator.