Caribou, wolves and man.

The migratory tundra caribou/reindeer in the Holarctic now number three million and are increasing, approaching estimated pristine quantities in North America. In contrast, the sedentary forest races south of the tree-line number about 325 000 animals, and are declining in some areas in both Eurasia and North America. The chief natural mortality factor determining the survival of neonates and adults is predation; the wolf is the major predator. Recruitment and natural adult mortality are approximately equal when wolf numbers are about 6.5 per 1000 km(2). Wolf numbers have been reduced north of the tree-line in the Nearctic since the 1970s due to hunting facilitated by snowmobile transportation. But south of the tree-line wolf numbers may be locally high (>8 per 1000 km(2)) where moose have expanded their range in this century. Caribou can adapt to economic development in the Arctic if their space for mobility to cope with their predators is kept inviolate. It should be possible, through management of wolf numbers, to increase further the abundance of caribou and wolves and provide surpluses of both species for northern peoples, yet maintain a viable large mammal ecosystem in the Arctic.