Ecological Studies of Wolves on Isle Royale - Annual Report 1981-1982 (Covering the twenty-fourth year of research)
Peterson RO, Page RE, Stephens PW. 1982. Ecological Studies of Wolves on Isle Royale - Annual Report 1981-1982 (Covering the twenty-fourth year of research). Department of Biological Sciences, Michigan Technological University. Houghton, MI
This report summarizes the wolf - moose research on Isle Royale for 1981-1982. In 1982 only 14 wolves remained on the Island; the lowest level documented since they arrived on Isle Royale in the late 1940's. The dominant pack of four wolves claimed almost the entire Island. Three other breeding pairs and four single wolves were also found, but they were regularly tracked and chased by the dominant pack. A complete turn-around in wolf food availability was seen, and all groups of wolves had ample food. Only two years ago (1980) the historic high of 50 wolves was segregated into five packs. Changes in the moose population, probably prompted by the wolf decline, were no less dramatic. Swelled by almost 200 calves, the moose population increased to over 700 in 1982. A substantial rebounding of moose is certain if subsequent cohorts of calves match that born in 1981. If wolves exhibit a moderate rebuilding of numbers within a couple years, as we expect, this predator-prey system should soon approximate that described 25 years ago. Accumulating evidence suggests that we are witnessing a predator-prey cycle with an extended period of fluctuation. Other species observed during this winter study period include otter, beaver, fox, and gyrfalcon.
- Type
- Published Report
- Authors
- Peterson, Rolf; Page, Richard; Stephens, Philip
- Date of Issue
- 1982-04-30
- Publisher
- Department of Biological Sciences, Michigan Technological University
- Units
- ISRO
- Keywords
- Aerial Survey, Beaver (Castor canadensis), Ecology, Gray Wolf (Canis lupus), Isle Royale National Park, Mammals, Michigan, Monitoring, Moose (Alces alces)