Biodiversity promotes evolutionary change

Evolutionary biologists at the University of East Anglia have discovered a new link between biodiversity and the evolution of new species.

Studying plants and invertebrates on the Canary and Hawaiian Islands, Dr Brent Emerson and Dr Niclas Kolm found that the greater the diversity of species on an island, the higher the proportion of endemic species on that island.

The new research, published in Nature this week, underlines the importance of generating and maintaining species diversity and the dire consequences of any loss of biodiversity around the globe.

“Why some areas contain greater species diversity than others has been a fundamental question in evolutionary ecology and conservation biology,” said Dr Emerson, of UEA’s Centre for Ecology, Evolution and Conservation.

“Island biogeographic theory has identified the roles of immigration and extinction in relation to area size and proximity to source areas, and the role of speciation has also been recognized as an important factor. However, one as yet unexplored possibility was that species diversity itself helped promote speciation. Even after controlling for several important physical features of islands, we found that diversification was strongly related to species number.”

Volcanic island archipelagos such as the Canary and Hawaiian Islands provide the perfect opportunity to test if biodiversity can promote the evolution of new endemic species because of the absence of a historical connection between their component islands to each other or a mainland.

The flora and fauna of these archipelagos are rich in biodiversity, including a large number endemic species, each having evolved there. Using these endemic species as a measure of speciation, this work shows a clear relationship between the number of species within an ecosystem and the amount of evolutionary change that occurs.

Species diversity can drive speciation by Dr Brent C Emerson and Dr Niclas Kolm of UEA’s Centre for Ecology, Evolution and Conservation is published in Nature on April 21 2005.