"Despite its importance, species diversity has proven difficult to understand, in large part because multiple processes operating at various scales interact to influence diversity patterns," said biologist Tadashi Fukami of the University of Tennessee at Knoxville, lead author of a paper on the subject published in the July 24th issue of the journal Nature. "On evolutionary scales, species diversity is a result of speciation and extinction. But evolutionary processes are variable across space, interactive over time, and consequently, hard to identify. On ecological scales, diversity is a result of community assembly, how species join ecological communities over time."
Fukami and co-author Peter Morin of Rutgers University in New Jersey attempt to provide a novel ecological perspective from which to view diversity patterns. They argue that we can better understand diversity by considering how the history of community assembly interacts with other ecological variables to affect diversity.
Their paper addresses a topic of central importance in ecology, specifically the cause of different relationships between productivity and biodiversity observed in natural ecosystems. Ecologists define productivity broadly as the amount of energy available for ecosystem development in a given location. In this experiment, productivity was manipulated by changing the nutrient concentration of growth medium in ecological communities of microorganisms housed in a laboratory.