The effects of chronic wasting disease on mule deer fawn recruitment to weaning

Background/Question/Methods

During the last four decades, the effects of Chronic Wasting Disease (CWD) of cervid populations have emerged as a fundamental threat to wildlife recreation-based economies throughout western North America. (Miller 2002, Williams et al. 2002).  Our goal is to understand how CWD affects mule deer fawn recruitment up until weaning. Fawn recruitment is an important factor affecting the abundance of deer (Pojar and Bowden 2004). We will compare recruitment rates for CWD infected and non-infected female deer during weaning (August-September) and create a population dynamics model based on field observations. Radio-collared does were observed during weaning for two consecutive summers (2006-2007) to assess fawn presence or absence. 

Results/Conclusions

Initial results in 2006 suggested that fawn recruitment of CWD infected does was lower than non-infected does. We analyzed our results using simple logistic regression, likelihood and AICc.  The two competing models are: 1.) CWD influenced fawn recruitment with AICc =10.37 and 2.) CWD did not influence fawn recruitment with AICc =11.86.  In 2007, no difference was detected for infected and non-infected deer fawn recruitment. The CWD influenced fawn recruitment model had an AICc =10.63 and CWD did not influence fawn recruitment model had an AICc =8.83.  This may have been because most of the infected does only had the disease for a year or less. In 2006, it was unknown how long the infected does had the disease but their high mortality rate suggests that many of them were in their second year of the disease. In 2008, infected does will clearly be in their second year of the disease, thus we predict that infected deer populations will have a lower fawn recruitment than those not infected with the disease.