“Our functional classification re-sorts species according to their attributes, sizes, and sensitivities, and demonstrates the habitat conditions with which they are associated.”

This is no overnight "Eureka" discovery but the latest step in a 22-year development of a way to understanding how ecological communities in the plankton of lakes are put together. The problem for people working on phytoplankton is that many are either not bothered with species composition ("it's all autotrophic") or, if they are, rely on flow cytometry and pigmentation to sort it into phylogenetic categories. However, if we measured terrestrial vegetation by its chlorophyll content and we could sort things as far as Gramineae, Fagaceae, Chenopodiaceae, etc., we would have little to help us explain the very real differences in the structural attributes, physiological adaptation, and selectivity of the plants that make up the particular species associations characteristic of, for instance, semi-desert, grassland, wheatfields, and any number of different kinds of forest. Working with microscopes, people are very happy to be able to name things and know where they belong in the organismic kingdom. But natural communities are made up of many different species, usually from several phylogenetic groups, and which are well suited to (or at least tolerant of) the conditions that others do not. Our functional classification re-sorts species according to their attributes, sizes, and sensitivities, and demonstrates the habitat conditions with which they are associated. These do turn out to be polhyletic. We can look at plankton and learn about the habitat. Equally, we can devise or modify habitats and predict the floral composition. For many years, marine and freshwater plankton science has accumulated a vast fund of documented knowledge about what's in the plankton and what it does but without gaining the conceptual insights that permit prediction of temporal and seasonal change. It seems likely that the struggle to solve a predictive framework—which has evolved in publications in 1980, 1984, 1988, 1996 and now, 2002—has now reached a stage when it is recognized to be reasonably argued and reasonably workable. My co-authors had been using some of the earlier works and, through their experiences and careful refinements, have contributed, directly and handsomely, to the newest version. The published paper invited people to try it and improve upon it so you could say, I suppose, a few citations were rather "trailed." It has also been picked up by European Union institutions seeking new and straightforward ways of using sampled phytoplankton as an index of quality improvement or deterioration among European lakes.

Colin S. Reynolds
CEH Windermere Laboratory
Ambelside, Cumbria, UK