Diversity by Default

Why doesn't survival of the fittest seem to apply when many plants coexist? A report in this issue of Science ([ Hubbell et al .][1]) on tropical forests together with work from other habitats is converging on one explanation of this phenomenon--the recruitment limitation hypothesis. Simply put, this explanation states that stable heterogeneous populations of various types of plants coexist because--often by chance--the more successful competitors of the region do not happen to be locally present. [1]: http://www.sciencemag.org/cgi/content/short/283/5401/554