Body condition and population regulation by food resources in moose.

Abstract

In southwestern Québec, non-harvested moose populations stabilize at a density of ≈0.40 animal·km-2. In an attempt to test population regulation by food resources, we investigated moose body condition near this equilibrium density (0.37) and at 2 lower densities (0.22 and 0.17). Annual population growth rates were evaluated at 4, 18, and 24% respectively. We predicted that moose in the high density area would exhibit growth retardation and poorer body condition, compared to moose in the lower density areas. Measurements of head length, cranial breadth, heart weight, and kidney weight were collected from 443 moose killed during the regular autumn harvesting seasons of 1981 and 1982. There was no indication that body condition was poorer at high moose density, and hence no evidence that foraging conditions were deteriorated. We concluded that food limitation was not sufficient to explain the differences in population growth rates. Predation by wolves and/or black bears is presented as an alternative and testable hypothesis.