IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Hurley, M.A.; Unsworth, J.W.; Zager, P.; Hebblewhite, M.; Garton, E.O.; Montgomery, D.B.; Skalski, J.R.; Maycock, C.L. | |
| Demographic response of mule deer to experimental reduction of coyotes and mountain lions | |
| 2014 Conference Proceeding | |
We tested the efficacy of removing coyotes and mountain lions on mule deer population dynamics in southeastern Idaho, 1997-2006. We monitored aspects of mule deer ecology while experimentally manipulating predator populations within 10 Game Management Units. To determine survival and causes of mortality, 250 neonates, 284 6-month-old fawns, and 254 (521 deer years) adult females were monitored with radio telemetry in 2 study sites, one with coyote and mountain lion removal and one without 1998-2002. Survival of neonates was related to alternate prey abundance, coyote removal rates, and weather conditions. Winter fawn survival was influenced by summer precipitation, winter precipitation, mountain lion removal, and fawn mass. Adult female winter survival increased with mountain lion removal. December fawn-to-adult female rations (fawn ratios) increased significantly at maximum rates of mountain lion removal. Coyote removal had no significant effect on fawn rations, except after a weather-related population reduction. Coyote or mountain lion removal alone did not influence mule deer population growth rate, although the top model, including previous year's mountain lion removal and winter severity, explained 27% of the variance in population rate of increase. The lack of fawn ratio or population response to coyote reduction indicates that decreased neonate mortality due to coyote removal is partially compensatory. Mountain lion removal increased mule deer survival and fawn ratios, producing a minimal positive effect on growth rates. However, we observed some evidence for compensatory mortality in adult female mule deer during periods of prolonged mountain lion removal and when coupled with significant weather effects may reduce the effect of predator removal on population growth rate. |
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