Theory to integrate internal ecological processes and external driving forces

Background/Question/Methods

Ecological systems and environments change over both space and time. The simplicity of this statement belies its inherent complexity; environments, ecosystems, and the constituent parts of each are closely connected, while the spatial and temporal scales of their dynamics are often wildly different. Consequently, their influences on each other change as a function of the scales of our observations and their inherent dynamics. Ecologists have historically treated environmental effects as external processes independent of internal ecological feedbacks. Nowadays, many ecological studies rely on data-driven modeling to determine species and ecosystems respond to environmental conditions. Unfortunately, such data-driven modeling of species dynamics under current conditions may poorly predict how species will respond under novel conditions to which they are not adapted. We urgently need to predict how species and ecosystems will respond to these previously unseen changes in the abiotic environment. Under the Anthropocene, however, our perception of the interactions of the external environment and internal ecological dynamics has necessarily shifted. We must therefore acknowledge their feedback effects, and that the number and magnitude of these interactions are accelerating.

Results/Conclusions

Novel theoretical frameworks will help us to reveal new insights in an era defined by global change. We illustrate how feedback affects the dynamics of ecological processes using two examples: (1) how hydrological changes can alter the dynamic of wetland ecosystems like the Everglades and (2) how the speed of land-use change can have unintended consequences, positive and negative, for malaria transmission dynamics. Using these examples, we argue that the development of novel theory is needed to anticipate how these changes will affect countless interactions, and how changes in interactions will cascade into structural changes in communities. Furthermore, theory can help researchers to develop lab experiments and quasi-experimental sampling designs specifically to acquire knowledge on the feedback effects between external forces and internal processes. Indeed, theories must account for multiple feedbacks at several scales if we are to successfully anticipate how climate change will directly and indirectly affect ecosystem functions. These novel theories could lay the foundation for large-scale data collection by remote sensing and citizen-science and new mechanistic theories beyond correlational modeling. We conclude by stressing that such novel ecological theories should play a key role in guiding research when we need to solve critical environmental and ecological problems.