Print PageA fundamental yet elusive goal of ecology is to predict the composition of communities from the environmental conditions they experience. Research on terrestrial plants has increasingly shown that functional traits can provide a mechanistic link between environmental drivers and community composition, but this approach has not been tested on other dominant organisms such as planktonic microbes. We test whether microbial functional traits can predict community responses to environmental fluctuation, using a time series of the phytoplankton of the western English Channel.
Results/Conclusions
We show that species' responses to seasonal variation in light and nitrate, and resulting community changes, can be explained by lab-measured traits characterizing nitrate utilization, light utilization, and maximum growth rate. These traits are strong predictors of species' responses to environmental change, explaining 21-83% of interspecific variation in responses to seasonal fluctuation. A mechanistic eco-evolutionary model confirms that selection by varying environmental factors can drive these seasonal patterns of trait variation. Because these relationships were predicted a priori, using independently measured traits, our results demonstrate that functional traits provide a strong mechanistic foundation for understanding the structure and dynamics of phytoplankton communities. Furthermore, functional traits will be essential for projecting the response of primary producers in lakes and oceans to global environmental change.
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