Summary:

In this study, I used a large-scale exclosure experiment replicated along a topographically created-climatic gradient to investigate the effects on tick populations of both large herbivore removal and livestock (in the form of cattle) additions. In the experimental treatments, questing adult ticks increased by 21% when large herbivores were removed. However they decreased substantially, by 50%, when cattle were added. Climate mediated the effect of ungulates on questing tick density, particularly under the most arid conditions in the study. This was likely due to the changes in ground-level microclimates, as cattle grazing reduced landscape refugia for off-host ticks. Overall, I believe our work contributes further to the understanding of tick population responses to globally common human-induced rangeland alterations under the concurrent effects of climate change.