Ecological character displacement alters the outcome of priority effects during community assembly

Character displacement may facilitate species coexistence through niche partitioning. However, the degree to which character displacement influences broader patterns of community assembly is unclear. Here, we capitalize on a natural experiment of community assembly on the oceanic island of Bermuda. Over the past century, three species of ecologically similar but distantly relatedAnolislizards have been introduced to Bermuda where noAnolishas ever naturally existed. The Jamaican anole (A. grahami) arrived first in 1905 and dispersed rapidly across the island. Five decades later, the Antiguan anole (A. leachii) and the Barbadian anole (A. extremus) were introduced to independent locations. In 1991,A. leachiiandA. extremuswere observed to nearly meet at a contact zone, but not yet to coexist. We record that subsequent range expansion at this contact zone has been asymmetrical;A. leachiiinvaded the range ofA. extremus, but reciprocal invasion byA. extremushas not occurred. When in allopatry in Bermuda, both species occupy identical ecological space. However,A. leachiiunderwent rapid ecological character displacement to use arboreal habitat when invading the range ofA. extremus. These findings highlight how character displacement may influence the process of dispersal and drive patterns of coexistence and community assembly.