Ecological Studies of Wolves on Isle Royale - Annual Report 1990-1991 (Covering the thirty-third year of research)
Peterson RO. 1991. Ecological Studies of Wolves on Isle Royale - Annual Report 1990-1991 (Covering the thirty-third year of research). Isle Royale Natural History Association. Houghton, MI
This report summarizes the results of the 33rd year of field studies on Isle Royale, including summer moose studies. The report primarily describes wolf movements and population status during the winter studies. The 1991 wolf population dropped to 12 animals, equaling the lowest level recorded since studies began in 1959. As part of an intensified study to understand causes of the wolf decline, 8 of the 12 wolves alive in 1988 have now been live-captured, blood-sampled for disease and genetic studies, and released wearing radio collars. During the past year we have found no evidence that disease is currently an important factor in wolf dynamics, and their food supply should be increasing annually as the moose population ages. Loss of genetic variability and inbreeding in this small population may explain the low reproduction which currently endangers these wolves. In 1991 the moose population was estimated at 1313 (+-) 303, or about 2.4 moose/km2, suggesting that the population has stabilized after a 25% decline attributed to the influence of winter ticks. With wolves at such a low level, moose are expected to persist at high density until other sources of mortality intervene.
- Type
- Published Report
- Authors
- Peterson, Rolf
- Date of Issue
- 1991
- Publisher
- Isle Royale Natural History Association
- Units
- ISRO
- Keywords
- Aerial Survey, Ecology, Gray Wolf (Canis lupus), Isle Royale National Park, Mammals, Michigan, Monitoring, Moose (Alces alces), Radio Collar