Hybridisation: A ‘double-edged sword’ for neotropical plant diversity

Hybridisation can facilitate both evolutionary diversification and extinction and has had a critical role in plant evolution, with ~25% of species known to hybridise in some temperate floras. However, in the species-rich neotropical flora, hybridisation’s role in the evolution of diversity remains unclear. Our review examines studies of hybridisation in seed plants from across the Neotropics, and explores its outcomes on neotropical plant evolution. We review studies on a per-biome basis and a spectrum of evolutionary outcomes from hybridisation are evident across neotropical biomes and taxa. These range from short-term impacts, such as the broadening of ecological amplitude in hybrid progeny with transgressive phenotypes and genetic swamping, through to long term impacts such as the generation of new lineages. Among these studies certain themes emerge, such as the pervasive hybridisation among species-rich plant radiations from the Andean Páramos, suggesting a role for hybridisation in rapid diversification events. Finally, we highlight that hybridisation is relatively understudied in the neotropical flora despite its remarkable species-richness. The advent of genomic techniques can facilitate the study of hybridisation and its effects in understudied biomes and plant groups. The increasing availability of genomic resources will eventually allow comparisons between tropical and temperate floras and therefore shed light on hybridisation’s evolutionary impacts across the latitudinal biodiversity gradient.