Dynamics of Isle Royale Wolves During a Chronic Population Decline, 1987-1993
Peterson RO and Thurber JM. 1994. Dynamics of Isle Royale Wolves During a Chronic Population Decline, 1987-1993. IN: Study of Wolf Decline, R O Peterson, 1994 Chapter 9. School of Forestry and Wood Products, Michigan Technological University. Houghton, MI
The ecology and demography of wolves in ISRO were examined during a sustained and unexpected population decline. After a population crash in 1981-1982 that Peterson and Page attributed to food shortage, wolves continued to decline in 1984-1988 because of unusually high mortality. When high mortality abruptly ceased >1988, however, poor reproductive success prevented recovery of the wolf population. Disease screening initiated in 1988 revealed the final stages of canine parvovirus (CPV-2) occurrence in the population, a new disease that likely arrived by 1981. Disease probably played an important, previously unrecognized, role in the wolf population crash of 1981-1982 and may have contributed to subsequent high mortality through 1987, but there was no evidence of disease involvement in reproductive failure in 1989-1993. There was little support for hypotheses linking the wolf decline to relative food shortage or random demographic fluctuations. Wolf genetic characteristics support the hypothesis that reproductive success in this isolated population declined because of inbreeding depression, exacerbated by a population bottleneck in 1982, high mortality in 1981-1988, and unequal reproductive success among alpha wolves both before and after the crash. By 1993 the population was at a precariously low level, with greatest extinction risks being the random elimination of one sex and a new cycle of disease.
- Type
- Published Report
- Authors
- Peterson, Rolf; Thurber, Joann
- Date of Issue
- 1994
- Publisher
- School of Forestry and Wood Products, Michigan Technological University
- Units
- ISRO
- Keywords
- Animal Studies, Disease, Ecology, Genetics, Gray Wolf (Canis lupus), Moose (Alces alces), predator-prey