Neophytes may promote hybridization and adaptations to a changing planet

Human activities are breaking down geographic barriers to species dispersal, providing previously isolated taxa with unprecedented new opportunities for hybridization. Empirical studies on the effects of neophytes on hybridization and on the evolutionary consequences of these processes remain, however, scarce. Here we integrated Kew’s Plants of the World Online database with the Global Naturalized Alien Flora database to study the spatial and taxonomic overlap of hybrids and neophytes. Using the largest dated plant phylogeny to date, we compared diversification rates of genera containing hybrids and neophytes to genera containing neither. In addition, we used the well-studied hybrid flora of Britain to ask whether hybrids are adapted to anthropogenic disturbance and occur in habitats with a higher human footprint than their native and neophyte parents. Overall, we document positive ties between contemporary biodiversity redistribution and hybridization. Neophyte incidence was positively related to hybrid incidence both spatially (across countries) and taxonomically (across genera). Diversification rates were nearly three times higher in genera with both hybrids and neophytes than in genera containing neither. Hybrids occurred, on average, in areas with a higher human footprint than their parents, with little evidence that hybrids threaten native species throughout their range in more native habitats. Together, our results suggest species naturalizations and hybridizations need not have only negative evolutionary outcomes. Against a backdrop of rapid global change, anthropogenic hybridization may promote recombination of genetic variation and help conserve genetic diversity in disturbed environments.