Tick numbers are higher in areas with thick barberry understories, as opposed to areas with controlled barberry or no barberry. In one study,  in a barberry infected area, while only  in otherwise similar area with no barberry present.
The number of ticks is greater in regions where thick barberry undergrowth exists, as opposed to areas with controlled or no barberry at all. A study showed that tick populations were higher in a barberry-infested area compared to an otherwise similar area lacking barberry.