Bird diversity and environmental heterogeneity in North America: a test of the area–heterogeneity trade‐off
AIM: Deterministic niche theory predicts that increasing environmental heterogeneity increases species richness. In contrast, a recent stochastic model suggests that heterogeneity has a unimodal effect on species richness since high levels of heterogeneity reduce the effective area available per species, thereby increasing the likelihood of stochastic extinction (the ‘area–heterogeneity trade‐off’). We tested these contrasting predictions using data on bird distributions in North America. LOCATION: North America.