Density Dependence and Stochastic Variation in Overabundant, Unmanaged White-tailed Deer Herds of Eastern National Parks
Wilkinson SA. 2013. Density Dependence and Stochastic Variation in Overabundant, Unmanaged White-tailed Deer Herds of Eastern National Parks. State University Of New York Col. Of Environmental Science & Forestry
In many parts of the eastern U.S., white-tailed deer populations have existed for decades at densities high enough to cause public concern due to decreased forest regeneration, more frequent deer-vehicle collisions, and increased spread of human and animal diseases. The National Park Service (NPS) has initiated management actions at several sites focused on decreasing deer density without a broader understanding of population dynamics that contribute to population size and fluctuation over time. Using 7-year to 13-year sets of deer monitoring data from 16 NPS sites, I estimated parameters of the theta-logistic model (TLM), a widely-used population model which integrates the two key factors of population dynamics: density dependence and environmental stochasticity. I found that: (1) the density dependent parameter of the TLM (&thetas;) can be estimated from time-series if the ratio of process variance to sampling variance is more than 1.6 and if parameter bias is simulated and corrected; (2) deer populations existing at a lower equilibrium density fluctuated more over time and conversely larger populations fluctuated less; and (3) overall population variation is positively related to environmental stochasticity.
- Type
- Academic
- Authors
- Wilkinson, Sarah
- Date of Issue
- 2013
- Publisher
- State University Of New York Col. Of Environmental Science & Forestry
- Units
- GRSM
- Keywords
- Cades Cove, GRSM-01806, Odocoileus virginianus, thesis, White-tailed Deer