Beyond neutral science.

Biodiversity science is unusual in that an emerging paradigm is not based on a specific process, but rather depends largely on stochastic elements, perceived as neutral forces. Here I suggest that these forces, which have been justified, in part, by the concepts of symmetry and equalizing mechanisms, have application to the understanding of stochastic models but do not constitute forces that operate in nature. Another process now regularly classified as a neutral force, limited dispersal, represents a fundamental demographic process that is not neutral with respect to species differences, but rather differs among species in important ways. Finally, I suggest that the dramatic shift in ecological research to focus on neutrality could have a cost in terms of scientific understanding and relevance to real biodiversity threats.