Princeton University Professor Ignacio Rodríguez-Iturbe and colleagues say they've invented a method for turning simple data about rainfall and river networks into accurate assessments of fish biodiversity, allowing better prediction of the effects of climate change and the ecological impact of man-made structures like dams.

The researchers say the mathematics behind the new method also can be used to model and predict the transmission of waterborne illnesses, as well as vegetation patterns on land adjacent to rivers.

The researchers said their computer simulation program allows them to use rainfall measurements and the structure of river networks to predict how many species of fish will occupy any given region.

"It is an extremely simple model, but it predicts absolutely fantastically well all of the characteristics of biodiversity that we were interested in," said Rodríguez. "Our model implies that water dynamics have a commanding effect on biodiversity in river basins."

The study appears in the May 8 issue of the journal Nature.