Diversification rates in large-scale moss assemblages along latitudinal and climatic gradients across the world.

Species richness in any area results from the interplay of the processes of speciation, extinction, and dispersal. The relationships between species richness and climate should be considered as an outcome of the effects of climate on speciation, extinction, and dispersal. Diversification rate represents the balance of speciation and extinction rates over time. Here, I explore diversification rates in mosses across geographic and climatic gradients worldwide. Specifically, I investigate latitudinal patterns and climatic associations of the mean diversification rate of mosses at global, hemispheric, and smaller scales. I find that the mean diversification rate of mosses is positively correlated with species richness of mosses, increases with decreasing latitude and increasing mean annual temperature and annual precipitation, and is more strongly associated with mean annual temperature than with annual precipitation. These findings shed light on variation of species richness in mosses across the world. The negative relationship between species richness and latitude and the positive relationship between species richness and mean diversification rate in mosses suggest that higher moss species richness at lower latitudes might have resulted, at least to some degree, from higher moss diversification rates at lower latitudes.