Data from: Accelerated speciation in temperate Cannabaceae: The role of pre-adaptation, ecological opportunities, and niche divergence

Macroevolutionary processes underlying biome transitions and global patterns of species diversity and ecological traits remain poorly understood across many clades. We investigated tropical-to-temperate biome transitions in Cannabaceae (the hemp family) to test the hypothesis that pre-adaptive traits, particularly deciduous leaf habit, together with ecological opportunities in temperate environments, promoted niche divergence and elevated speciation rates. Using a well-resolved, time-calibrated phylogeny representing approximately 70% of extant Cannabaceae diversity, we integrated data on leaf duration, species occurrences, and environmental variables. Phylogenetic comparative analyses were employed to assess correlated evolution between deciduousness and biome transitions, and to estimate speciation and niche evolution rates across tropical, temperate, and widespread lineages. Our results support correlated evolution between leaf habit and biome shifts, with deciduous lineages exhibiting higher rates of transition from tropical to temperate regions than evergreen lineages. Temperate lineages, particularly those associated with a hidden state, showed increased speciation rates relative to tropical lineages. In addition, niche divergence occurred more rapidly in temperate than in tropical lineages, especially along climatic dimensions related to temperature variability and seasonal precipitation. These findings suggest that deciduousness functioned as a pre-adaptive trait facilitating colonization of temperate environments in Cannabaceae, and that the expansion of temperate biomes since the Oligocene provided ecological opportunities that promoted speciation through multidimensional niche divergence.