Synergistic Population Density and Environmental Effects on Deer Body Condition

The ability to predict energy and protein allocation to different body condition parameters according to environmental constraints is a key component in understanding the processes underlying population dynamics. We investigated the influence of a proxy of population density and environmental factors on individual body condition parameters of female white-tailed deer (Odocoileus virginianus) based on long-term monitoring (2002-2013) of autumn harvest on Anticosti Island, Quebec, Canada. We used dressed body mass, peroneus muscle mass, and rump fat thickness to evaluate the nutritional status of 3,123 adult females. Density index and winter precipitation negatively affected fat reserves in autumn. We detected the negative effect of winter precipitation on fat reserves only at low density likely because individuals at high density were already in bad condition. High normalized difference vegetation index (NDVI) in spring (May-Jun) reduced body mass, and this influence was more pronounced under high population density, probably because individuals at high densities were less likely to be buffered against environmental fluctuations when resources were scarcer than resources at low population density. Using different body condition parameters, our results provide additional insights on how northern ungulates influenced by food limitation may respond to future environmental changes. We recommend managers to collect long-term data on multiple physiological indicators of body condition. These data could be used as an index of ecological changes and provide a quantitative basis to help setting harvest objectives or supporting adaptive management. (c) 2020 The Wildlife Society.