Relationship of minimum winter temperature and temperature seasonality to the northern range limit and species richness of trees in North America

Biologists have considered both winter coldness and temperature seasonality as major determinants of the northern limits plants animals in Northern Hemisphere, which turn drive well-known latitudinal diversity gradient. However, few studies tested two climate variables is primary determinant. In this study, we assess whether or more strongly associated with tree species richness North America. Tree were recorded each 1198 quadrats 110 km × We used correlation regression analyses to relationship latitude boundary species, per quadrat, seasonality. Species was analyzed within 38 longitudinal, i.e., north-south, bands (each being >1100 long wide). The latitudes range three times better correlated minimum temperatures at those than On average, together explained 81.5% variation examined, uniquely six-fold (33.7% versus 5.8%) did Correlations stronger correlations for most longitudinal analyzed. Compared seasonality, distributions high latitudes, likely a important driver