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Land Use, Immune Function, and Stress under Unpredictable Winter Weather Conditions
Weather and land use are significant sources of selection on wild populations and major drivers of ecological processes. As such, understanding their influence on life history traits, individual physical condition, and subsequent population dynamics is crucial for predicting how populations will respond under the increasingly unpredictable climatic conditions associated with global climate change.We examined a variety of important ecological and physiological variables in a winter resident species, Northern Bobwhite (Colinus virginianus) during the winters of 2016-2017 and 2017-2018 in Furnas County, in south-central Nebraska, USA. Winter use areas ranged in size from approximately 6 hectares to over 110 hectares. Corn stubble, wheat stubble, and rangeland were the most abundant cover types within the winter use ranges but early succession woody cover, mainly American plum (Prunus americana) was selected over all other cover types in both winters, followed by rangeland during the winter of 2016-2017, and CRP lands during the 2017-2018 winter. Two measures of innate humoral immune function during the winter, natural antibodies and complement, were not significantly related to age or sex in wild Northern Bobwhite. A stronger immune response with natural antibodies and complement was related to higher body condition as measured by the scaled mass index. ere were significant differences in immune function by covey afiliation, suggesting an environmental influence on innate immune function or maintaining a robust immune system, though land use and roost microhabitat within winter use areas was not significantly related to immune function. Baseline stress hormones as measured by corticosterone concentration in fecal samples also differed by covey and was influenced by nighttime temperatures and winter severity. Roost microhabitat was not significantly related to baseline stress hormones. Weather and land use indeed impact physiology and behavior and give rise to the potential for significant impacts to important life history traits. This potential will only increase as global climate change causes shifts in seasonal means and increases the magnitude and frequency of severe weather events, likely impacting Northern Bobwhite overwinter survival and perhaps early breeding season reproduction significantly along the northern periphery of their range.
Lipinski, Amanda Rose, "Land Use, Immune Function, and Stress under Unpredictable Winter Weather Conditions" (2019). ETD collection for University of Nebraska - Lincoln. AAI22616467.