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Impact of invasive eastern red cedar (Juniperus virginiana) on tick abundance at the microhabitat level

Horton, Olivia
Ticks are important vectors of pathogens in the United States so it is necessary to understand their ecology to properly manage their presence and inform the public of potential risks. Eastern red cedar (Juniperus virginiana; ERC) is an invasive tree species that is currently being studied to determine its impact on tick abundance and diversity in central and western Oklahoma. As part of larger landscape-focused study, this study focused on the impact of ERC on tick abundance at the microhabitat level by matching CO₂ traps in individual ERC trees with traps in nearby grassland sites at seven sites across central and western Oklahoma. Tick collections were performed solely in areas with 40% ERC encroachment, and each board placed under an ERC tree was paired with a board placed 50m in a nearby grassland area. Using 6 CO₂ traps (3 pairs) x 7 sites x 3-4 time points (66 total replicates), we collected ticks both from under individual ERC trees and grassland and then analyzed the results data by matched pair analysis. From 3,654 ticks collected, significantly more adult and nymphal ticks for Amblyomma americanum and adult Dermacentor variabilis were collected under ERC compared with matched grassland traps. However, significantly more Amblyomma americanum adults were collected under ERC in 4 out of 7 sites, while significantly more A. americanum nymphs were collected under ERC in only 1 out of 7 sites. We determined that the significance observed is site-specific for adults, but not for nymphs. No differences were observed for Amblyomma maculatum collections. Overall, ERC at the micro level within a pasture system appears to provide sufficient habitat for A. americanum and D. variabilis throughout central and western Oklahoma.