Trends of Winter Nutritional Restriction, Ticks, and Numbers of Moose on Isle Royale
Delguidice GD, Peterson RO, Samuel WM. 1997. Trends of Winter Nutritional Restriction, Ticks, and Numbers of Moose on Isle Royale. The Journal of Wildlife Management. 61(3):895-903
During a 7-year study, we monitored winter nutritional restriction of moose (Alces alces) and moose numbers on Isle Royale (winters 1987-88 to 1993-94). Over the 7 winters, the estimated moose population decreased 26% from an historic high of 1,653 (winter 1987-88) to 1,216 (1989-90), then increased to a new high (1,880 and 1,770) by winters 1992-93 and 1993-94. During that time, there was a significant (P = 0.0486) negative relation (r = -0.84) between the percent of urine specimens collected from snow (snow-urine) in late winter with urea nitrogen:creatinine (UN:C) ratios ≥3.5 mg:mg and percent change in the moose population from winter 1987-88. Mean urinary UN:C of moose residing on the east and west ends of Isle Royale declined (P ≤ 0.0001) among years; however, slopes of the 2 trends were different (P = 0.0001). The nutritional restriction and decline in moose numbers appeared to involve an epizootic of the winter tick (Dermacentor albipictus; indicated by percent moose observed with tick-induced hair breakage and loss). During winters 1987-88 to 1989-90, the percentage of late winter snow-urine specimens with UN:C ratios indicative of severe nutritional restriction ranged from 47 to 58%; however, the percentage decreased to zero by winter 1993-94 as the tick infestation subsided and moose numbers increased.
- Type
- Journal Article
- Authors
- Delguidice, Glenn; Peterson, Rolf; Samuel, William
- Units
- ISRO
- Keywords
- Animal Studies, moose(Alces alces), Nitrogen, Nutrients, urine chemistry, winter ticks(Dermacentor albipictus)