Rare Tree Species Thrive in Local Neighborhoods.

FORESTRY research; RARE plants; PLANT species diversity; WILLS, Christopher; BIODIVERSITY; PLANT classification; NATURAL resources; TREES

The article reports that some of the tropical-forest trees are surprisingly becoming more diverse over time. Christopher Wills, an evolutionary biologist at the University of California, San Diego, tapped data on seven research forests monitored by the Center for Tropical Forest Science, based at the Smithsonian Tropical Research Institute in Panama. The researchers did two types of analyses. To track changes in the number of species over time, they divided the forests into 10-meter squares, counted the number of tree species in each square and calculated the density of those species. Within these plots, more trees of the common species died over time than did members of rarer species, increasing the relative representation of rare species. The findings challenge a theory about forest diversity. According to the so-called neutral theory, plant species are gained and lost randomly. Thus, diversity is just an accident of history, says Wills. Such a result should be exciting to ecologists studying grasslands and temperate forests.