Using advances in Empirical Dynamical Modelling to investigate the impacts of climate variability on fish

Extreme climatic and weather events like marine heatwaves (MHWs) are receiving growing attention for their potential consequences on ecological systems as evidence is mounting these may pose as significant a threat to biodiversity as long-term global warming trends. However, ecological systems are highly complex, generally consisting of hundreds if not thousands of interacting species and environmental variables. The dynamics of these complex systems may be nonlinear and chaotic, meanwhile the number of variables observed are few. This imposes strong limitations on what ecologists can infer about the effects of extreme events on these systems whether using standard linear statistical approaches or attempting to fit more complex models. Meanwhile, emerging techniques in Empirical Dynamical Modelling (EDM, e.g. gaussian process-based EDM), using Taken’s Theorem to construct diffeomorphisms of the dynamical system’s attractor from which time-series observations have been made, are increasing in their applicability to existing ecological data. We explored using these techniques to gain insight into the dynamics of demersal fish populations (obtained from one of the longest running ecological surveys) in the face of climate variability. Using these methods we obtained good approximations of attractors for predicting the observed dynamics of both fish and climatic variables used to characterize climate variability (e.g. severity and duration of MHWs). But have found little to no evidence for any significant recurrent impacts of one on the other. This suggests any impacts of these extreme events experienced by these demersal fish thus far are either insignificant in comparison to other drivers of their dynamics or any significant impacts of these events have been largely unique to the system state under which they occurred.

Using advances in Empirical Dynamical Modelling to investigate the impacts of climate variability on fish

Monday, July 14 at 6:00pm in

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Emma Walker

"Using advances in Empirical Dynamical Modelling to investigate the impacts of climate variability on fish"

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