Species-Specific Population Dynamics of Cervids in a Multipredator Ecosystem

Kunkel, Kyran; Pletscher, Daniel

In response to the natural experiment created by gray wolf (Canis lupus) recolonization of the Glacier National Park area, from 1990 to 1996 we examined population trends and female survival rates of white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus), and moose (Alces alces) preyed upon by wolves, cougars (Puma concolor), bears (Ursus spp.), coyotes (Canis latrans), and humans. The effects of the complete suite of native large carnivores on prey have not been previously reported. Annual survival rates were 0.74 for 64 deer, 0.83 for 53 elk, and 0.88 for 47 moose. Cougars and wolves were the most significant sources of mortality for deer (0.09 and 0.06 respective annual cause-specific mortality rates) and elk (0.06 and 0.03 respective annual cause-specific mortality rates), and wolves and bears were the most significant sources of mortality for moose (0.03 and 0.04 respective annual cause-specific mortality rates). All age classes of deer were relatively equally vulnerable to predators, while young and old moose and elk were most vulnerable. Moose survival rates were higher where wolves were absent and where white-tailed deer were present. Deer and elk populations declined as wolf numbers increased (λ = 1.20). The moose population remained relatively stable. Predation appeared to be the primary factor limiting growth of deer and elk populations in this system. Predator-prey managers need to carefully monitor prey populations in areas wolves recolonize. Managers may be able to manipulate alternative prey densities to enhance prey populations that are affected by wolves, cougars, and bears.

Species-Specific Population Dynamics of Cervids in a Multipredator Ecosystem

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