Abstract
Recent biological analyses suggest that reductions in dispersal ability have been key drivers of diversification across numerous lineages. We synthesise emerging data to highlight similarities regarding the causes and consequences of dispersal reduction across taxa and ecosystems, as well as the diverse genomic mechanisms underpinning these shifts. Natural selection has acted on standing genetic variation within taxa to drive often rapid - and in some cases parallel - losses of dispersal, and ultimately speciation. Such shifts can thus represent an important nexus between adaptive and neutral diversification processes, with substantial evolutionary consequences. Recognition of the links between these concepts that are emerging from different fields, taxa and ecosystems is transforming our understanding of the fascinating role of dispersal reduction in the formation of biodiversity.