The effects of environmental heterogeneity within a city on the evolution of clines

There is increasing evidence that environmental change associated with urbanization can drive rapid adaptation. However, most studies of urban adaptation have focused on coarse vs. rural comparisons or sampled along a single urban–rural gradient, thereby ignoring the role within-city heterogeneity might play in to environments. In this study, we examined fine-scale variation presence hydrogen cyanide (HCN)—a potent anti-herbivore defence—and its two underlying genes (Ac and Li) between park green spaces surrounding suburban habitats for five city parks Greater Toronto Area. We show has driven formation micro-clines HCN scale <2 km, though strength varied across parks. Interestingly, these were by lower frequencies inside spaces, are therefore opposite direction predicted based previously described patterns frequency gradients. Synthesis: These results suggest larger scale, adaptive clines occur complex matrix within cities drives microclines varying strengths directions.