Harnessing trait–environment interactions to predict ecosystem functions

In a changing world, predicting ecosystem functions is essential to ensuring human well-being and survival. However, commonly used trait-based predictive approaches frequently lack predictive power. Statistical and conceptual attempts to better incorporate environmental factors into trait-based predictions have done so by integrating indirect, trait-mediated effects therein. Here, we define ecosystem functions as changes in the state, position, or nature of energy or matter within an ecosystem, and then illustrate how environmental factors can directly affect ecosystem functions. Given that the effects of organismal traits and environmental factors are not necessarily additive, we also propose that interactions between organismal traits and environmental factors (hereafter, trait–environment interactions) have explanatory power. We propose a conceptual framework in which organismal traits, environmental factors, and trait–environment interactions, together with the environment's effects on traits (plasticity) and traits’ effects on the environment (ecosystem engineering), can explain ecosystem functions. We conclude by discussing the importance of considering trait–environment interactions and identifying future avenues of exploration.