Tick Utilization of Eastern Redcedar¹ Encroached Areas at the Individual Tree Scale in Oklahoma

The Great Plains region is experiencing a biome-level conversion as grasslands are being rapidly encroached by eastern redcedar (Juniperus virginiana L.; ERC) which, in turn, causes abiotic and biotic changes throughout the region. These changes brought about by ERC encroachment are providing habitat for ticks and mosquitoes that increase the risk for vector-borne diseases. This study evaluated the influence of ERC on the abundance of ticks at the tree level by matching CO₂ traps under individual ERC trees with traps in nearby grass patches at seven sites across central and western Oklahoma. From 3,654 ticks collected, significantly more adult and nymphal Amblyomma americanum (L.) and adult Dermacentor variabilis (Say) were collected under the individual ERC trees compared to the adjacent grass patches. Along with growing evidence that larger-scale ERC encroachment increases the abundance of ticks, this finding suggests that even single ERC trees within an encroached area provide sufficient habitat for A. americanum and D. variabilis. This study also contributes novel information about the fine-scale effects of this invasive encroaching tree species on the ecology of vector-borne disease systems.