Figure 2: Patterns of species interactions and their drivers. (A) Bird attack rate was lowest in the 2018/19 cohort. More intriguingly, spatial variation in attack rate was highest in 2018/19 despite the homogenization of a key environmental variable—the proportion of stems being knocked to the ground. (B) This counterintuitive result occurred because the homogenization of one environmental factor (stems being knocked over) exposed galls to the influence of another environmental factor (distance to trees). When galls remained on standing stems the distance of the gall from a treeline made little difference for bird attack rates, but when most stems were knocked down, birds foraged disproportionately near the treeline. Letters in (A) denote differences in variance. Colors in (B) show predicted values from a linear mixed model. Note that the percentage of stems knocked down and the distance of a population from the treeline are uncorrelated (coef=0.002, P=0.96 in a linear mixed model).