Professor University of Guelph GUELPH, Ontario, Canada
Background/Question/Methods
The implications of multiple, interacting stressors on food webs are not well understood, despite potentially having drastic implications for food web structure and function, and despite the global human footprint on nearly all ecosystems rapidly increasing. At the same time, some of the underlying abiotic processes regulating ecosystem functioning (e.g., seasonality, weather patterns, etc.) have been, until recently, largely ignored in research. Alarmingly, though, climate change is fundamentally altering underlying these processes and ultimately “rewiring” entire food webs.
Here, I will discuss how general theoretical concepts can be unified and applied across multiple systems undergoing global change. To do so, I will use dynamical systems theory to investigate the effects of global change – multiple anthropogenic stressors and environmental variability – on various food web modules (i.e., fundamental biological structures) and synthesize the results towards a theory for ecosystems under global change. Specifically, I will highlight how environmental factors (changing abiotic processes) interact with underlying dynamics of species interactions in ways that may fundamentally alter ecosystem functioning and resilience.
Results/Conclusions
I will show that signatures of environmental noise can generate highly complex and/or unexpected outcomes, even in relatively simple dynamic models. However, the geometric characteristics of our models allow us to unpack the interaction between local and non-local dynamics, such that we can begin to understand the underlying mechanisms driving these seemingly unexpected outcomes. Furthermore, the outcomes depend on asymmetries at a variety of scales: asymmetries in local stability properties; between the periodicity of environmental forcing and the underlying system dynamics; and between relative biological speeds (e.g., growth rates) of interacting species. By unpacking these asymmetries mathematically and using empirical examples, we are in a position to integrate research that highlights how global change may drive consistent patterns across scales.
The modules I will discuss here individually contribute novel theory to the study systems they are inspired by, and together contribute to a growing body of theoretical ecology for a changing world. Altogether this research strongly suggests that global change will likely fundamentally alter the dynamics and resilience of ecosystems, and by mechanistically beginning to generate this theory we are also step closer to understanding these changes and finding solutions that can mitigate the looming impacts of anthropogenic global change.
