Biodiversity is not distributed evenly across the planet, but follows patterns such as the latitudinal species gradient or assemblages in regional hotspots. Understanding these differences in spatial distribution and what causes them is a crucial aspect of evolutionary ecology.
This paper uses the global distribution of conifers to explore mechanisms underlying biodiversity hotspot formation. Its authors derived species ranges and—subsequently—assemblages from GBIF-mediated occurrence data to identify eight richness hotspots, while analysing a wide range of characteristics to compare these with non-hotspots.
In their analysis, they find greater topographic heterogeneity in hotspots than surrounding areas, although not consistently associated with differences in climate or soil types. Comparing traits, the authors show minor, but non-consistent differences between hotspot and non-hotspot species.
Overall, the study suggests a bigger role played by geography than biology, and that hotspots form not as a result of unique diversification processes, but rather a simple accumulation of regional diversity in stable, mountainous areas.