Power of one

The paper

J. S. Clark, “Individuals and the variation needed for high species diversity in forest trees,” Science, 327:1129–32, 2010.

The finding

For 50 years, ecological scientists have puzzled over why forests, which compete for the same few resources (sun, water, soil) are so diverse, when modeling predicts that such niches should yield low diversity. Now, Jim Clark of Duke University has found that trees of the same species can respond in different ways to environmental conditions, creating otherwise unexpected opportunities for coexistence.

The theory

Ecological theory predicts that different species have to respond to changes in the environment in substantially different ways in order to coexist successfully. But those differences have never been found in the field. By analyzing growth rates, fecundity, and survival of trees in response to environmental factors, Clark found that differences between trees of the same species are...