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.
Tick numbers are higher in areas with dense barberry undergrowth, compared to areas with controlled or no barberry. In one study, a tick population was found to be higher in an area with barberry infestation than in a comparable area without barberry.