Prey specialization and morphological conformation of wolves associated with woodland caribou and moose

David M.A Wiwchar,Frank F Mallory

doi:10.7557/2.32.2.2278

Abstract

Morphological analysis of wolves associated with woodland caribou in late succession boreal coniferous forests north of the commercial cut line and those associated with moose in early succession boreal deciduous forests south of the commercial cut line were studied in Ontario. Socalled “moose-wolves” could readily be distinguished from “caribouwolves” in both genders using a few morphological measurements. Wolves associated with woodland caribou were significantly smaller in most measurements, and increased in size within seven years post-harvest as moose totally replaced caribou in the ecosystem. Whether this change in wolf morphology is related to micro-evolutionary change, the migration of larger “moose-wolves” into the area, or both, remains unclear.

Highlights

Woodland caribou (Rangifer tarandus caribou) dominated most of the Boreal Forest Biome throughout Canada (Bergerud, 1974) and few moose (Alces alces) existed in the northeast of Ontario prior to the mid-1800s (Krefting, 1974)
Moose have benefited from early succession forests created by timber harvest (Krefting, 1974) and it has been hypothesized that wolves increase pack sizes (Bergerud, 1974; Messier, 1985; Seip, 1992; Rettie & Messier, 1998) and body mass (Hillis, 1990; Mallory & Hillis, 1995) due to increased prey size
Wolf carcasses were obtained from trappers across northwestern Ontario between 1997 and 1998 and wolf scats were collected from moose and caribou ranges

Summary

Introduction

Woodland caribou (Rangifer tarandus caribou) dominated most of the Boreal Forest Biome throughout Canada (Bergerud, 1974) and few moose (Alces alces) existed in the northeast of Ontario prior to the mid-1800s (Krefting, 1974). Moose have benefited from early succession forests created by timber harvest (Krefting, 1974) and it has been hypothesized that wolves increase pack sizes (Bergerud, 1974; Messier, 1985; Seip, 1992; Rettie & Messier, 1998) and body mass (Hillis, 1990; Mallory & Hillis, 1995) due to increased prey size This shift in the predator–prey system is hypothesized to result in the extirpation of local woodland caribou populations due to greater wolf numbers and wolf body mass and the loss of prime habitat (Hillis, 1990; Seip, 1992; Mallory & Hillis, 1995). This shift in the predator–prey system is hypothesized to result in the extirpation of local woodland caribou populations due to greater wolf numbers and wolf body mass and the loss of prime habitat (Hillis, 1990; Seip, 1992; Mallory & Hillis, 1995). Bergerud (1990) hypothesized that rareness was an anti-predator strategy of caribou, and Lariviere et al (2000) and Cumming (1975) suggested the clumping strategy of caribou would fail when moose were present in high

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