Testing and extending the neutral theory of biodiversity in lake communities

Hubbell's (2001) neutral model describes how local communities are structured if population dynamics are statistically identical among species in a constant, possibly patchy, environment with random speciation. Tests of this model have been restricted largely to terrestrial communities. Here I tested the fit of this neutral model to fish, zooplankton and phytoplankton species-abundance distributions from 32 well-studied lake communities varying widely in lake size and productivity. I measured the fit of the communities to the neutral model in three ways. All but one zooplankton (9 of 10) and all but three fish (10 of 13) communities were consistent with all three measures of fit. However, all nine phytoplankton communities did not fit the neutral model by at least one measure. I showed that a simple extension of the neutral model could generate a variety of species-abundance distributions similar to both phytoplankton and neutral communities.