Well-designed monitoring strategies are vital to obtaining data required to adequately determine population parameters and produce robust mule deer population estimates. Explicit knowledge of population parameters are needed to effectively manage deer whether hunted or part of multi-species conservation planning programs. In San Diego County, deer are both managed as a game species and a species of conservation interest. The southern mule deer subspecies (Odocoileus hemionus fuliginatus) that ranges from south of Los Angeles to Baja California, Mexico is non-migratory and little is known about their populations. In particular, population parameters are virtually unknown, which makes managing harvest limits challenging. Working collaboratively in close partnership with the California Department of Fish and Wildlife, we will implement a statistically rigorous and repeatable population survey for resident deer within the Transverse and Peninsular Ranges to produce reliable estimates of population abundance and density and detect rates of population change to inform management strategies for the species.
Historically, deer population size has been derived from uncorrected data obtained from minimum count helicopter survey. Data collected from aerial survey can underestimate population size and result in low precision due to visibility bias and inefficient sampling design. As such, we’ll be using GPS telemetry, ground-based surveys, fecal DNA sampling, and remote cameras to validate aerial survey estimates. We will use data from these validation approaches and covariate data from aerial surveys (e.g., terrain, vegetation, observer position, flight speed) to correct those estimates using a sightability model. This approach will also allow us to generate confidence intervals around our population estimates.
Additional Research Questions
In addition to addressing the research needs of the California Department of Fish and Wildlife to improve management of southern mule deer as a game species, we will also be focusing on questions of conservation concern. These questions are still in development but will address:
- Disease and health status of deer
- Impacts of habitat fragmentation on deer movement and landscape connectivity
- Gene flow among populations of southern mule deer in San Diego County
SDSU Project Team