. The Canadian field-naturalist. Natural history. 71 76 81 86 91 96 1500 §1000 £ 'C (0 £500 Magpie. â Fall Winter 80 85 90 95 Figure 3. Harvest of Caribou in the zones of intensive use (70% kernels) where hunting was allowed between 1971 and 1999. Quebec City, even at that time. Its distribution was probably limited to sites dominated by coniferous trees. The main direct causes of the Caribou decline ap- pear to have been overharvesting and predation, and in some cases, the transmission of the Meningeal Worm (Parelaphostrongylus tenuis) by White-tailed Deer (Odocoileus virginianus) (Bergeru
. The Canadian field-naturalist. Natural history. 71 76 81 86 91 96 1500 §1000 £ 'C (0 £500 Magpie. â Fall Winter 80 85 90 95 Figure 3. Harvest of Caribou in the zones of intensive use (70% kernels) where hunting was allowed between 1971 and 1999. Quebec City, even at that time. Its distribution was probably limited to sites dominated by coniferous trees. The main direct causes of the Caribou decline ap- pear to have been overharvesting and predation, and in some cases, the transmission of the Meningeal Worm (Parelaphostrongylus tenuis) by White-tailed Deer (Odocoileus virginianus) (Bergerud 1974, 1988; Martin 1980; Bergerud and Mercer 1989; Jolicoeur 1993*). In addition, the development of agriculture and forestry probably led to growth in Moose and deer populations due to conversion of conifer stands to deciduous and mixed stands, which may have favoured an increase in Wolf abundance and, consequently, predation on Cari- bou (Bergerud 1974; St-Vincent 1981*; Bellehumeur et al. 1985*; Gingras et al. 1989; Jolicoeur 1993*). These habitat modifications may also have favoured the growth of Black Bear (Ursus americanus) popu- lations and predation on Caribou calves. There is mounting evidence that habitat changes and increased predation contribute to the decline of Woodland Cari- bou (Bergerud and Elliot 1986; Seip 1992; Seip and Cichowski 1996). The effect of any particular cause is difficult to quantify, since habitat changes that led to expansions in Moose, deer and Wolf populations occurred at a time when hunting was very intense. Nevertheless, Caribou disappeared from the southern part of its distribution range simultaneously all across North America. To explain this situation, Bergerud (1974) examined (1) changes in the availability of lichens due to forest fires and logging, (2) the impact of hunting and predation, (3) the combined effects of the avail- ability of lichens and predation, and finally, (4) the simultaneous impact of social pressures (foll
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