Loss of biodiversity is a hallmark of the human-dominated era, but our influence can also alter the processes that generate biodiversity. On page 543 of this issue, Helmus et al. study human-assisted movement of lizards around Caribbean islands, and show that a major geographic parameter of a classic theory of biodiversity has been replaced by an economic one (M. R. Helmus, D. L. Mahler and J. B. Losos Nature 513, 543–546; 2014).
The theory of island biogeography predicts that biodiversity is greatest on large and less-isolated islands (or other discrete habitat fragments), but the underlying processes of speciation and long-distance colonization are usually too slow for the theory to be tested directly.
The shipping trade has speeded things up for anole lizards in the Caribbean, transporting them around the islands as stowaways (pictured: Anolis equestris). The authors find that the resulting diversity of Anolis species fits theoretical predictions about island size, but that economic isolation — such as occurred on Cuba during the cold war — has overtaken geographic isolation as the other key factor.