Data from: North America defies a global trend of reduced vascular plant diversity in extreme environments: Are Asteraceae responsible?

Here we test this assumption agnostic to biological definitions of extremeness. Methods. We use upper and lower extremes of environmental variables on six continents to derive a set of 30 extreme abiotic stress layers that fall within nine extreme stress categories, each expected to affect the survival of terrestrial organisms.

We compare these to vascular plant species richness. Key results. While plant species richness decreases globally where extremes co-occur, the reverse is true in North America, where increased species richness is associated with regions where diverse types of extreme environmental conditions overlap.

Data for the largest family of plants (Asteraceae) support this finding in North America, and suggest that the diversity of this family by itself contributes much to this pattern. Conclusions. Our results demonstrate how insights may be gained through approaches that define environmental extremes agnostic of organismal tolerances.

While extreme environments do restrict plant diversity overall, by identifying regions where multiple extreme stressors co-occur, we can detect lineages that prosper under such conditions. Understanding of how extreme conditions have shaped plant diversity across the globe provides a historical context for shifting geographic distributions of extreme environmental conditions in the coming decades and centuries.