9th International Deer Biology Congress

AUTHORS: Paul C. Cross, U.S. Geological Survey, Northern Rocky Mountain Science Center; Kezia Manlove, Utah State University, Department of Wildland Resources; Angela Brennan, U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Unit, University of Wyoming

ABSTRACT: Behavior obviously plays a fundamental role in determining contact rates and transmission dynamics of disease. However, assessing the connections between host density, contact rates and disease transmission remains very challenging. I will review a series of empirical and modeling studies at multiple spatial scales that address this issue. Contact rates in social species are likely to depend upon both the group size distribution as well as how group size changes with regional population size. For some ungulates the group size distribution appears to be constant despite changing population size, which can lead to disease transmission that is not a function of population size. The largest groups of elk, however, get even larger as populations increase, creating a connection between population size and contact rate. However, directly correlating density to disease may still be difficult if movement rates among groups, or among areas of different densities, is high. In addition, the presence of an environmental disease reservoir may further obscure to the correlations between density and disease, due to potentially long time lags between deposition of pathogen and subsequent infections. Modeling results suggest that this can, in turn, create ecological traps— attractive habitats that begin as high quality due to their resources, but become heavily contaminated with pathogens and later become population sink. I conclude with some potential future research on how movement data may be used to model future disease spread and identify seasonal patterns of disease transmission.