Ecological Studies of Wolves on Isle Royale - Annual Report 1998-1999
Peterson RO. 1999. Ecological Studies of Wolves on Isle Royale - Annual Report 1998-1999. Isle Royale Natural History Association. Houghton, MI
Following a year when more than half the wolves died on Isle Royale, the wolves rebounded in 1999 at the highest rate ever documented, increasing from 14 to 25 wolves. The sudden drop the previous year was apparently a short-lived echo of the moose die-off in 1996. All four wolves captured live in 1997 and 1998 were disease-free. The wolf population continued to live in three territorial packs; with all three packs producing pups in 1998, and two packs brought six pups through to winter. Only one adult wolf died during the previous year, apparently killed by other wolves in a territorial dispute. Heavy wolf predation, a significant load of winter ticks, and unusually hot summer weather combined to keep moose numbers from rising very much (from 700 in 1998 to 750 in 1999). There are now enough wolves (30 moose:1 wolf) on Isle Royale to limit the rate of increase for moose and we expect the vegetation to recover somewhat. The beaver population has continued a long-term decline that reflects poor habitat as the forest matures after disturbance by fires in 1936 and during the 19th century.
- Type
- Published Report
- Authors
- Peterson, Rolf
- Date of Issue
- 1999-03-31
- Publisher
- Isle Royale Natural History Association
- Units
- ISRO
- Keywords
- Aerial Survey, Beaver (Castor canadensis), Ecology, gray wolf (Canis lupis), Isle Royale National Park, Mammals, Michigan, Monitoring, Moose (Alces alces), Radio Collar