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Séminaire de Chih-hao HSIEH

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Séminaire de Chih-hao Hsieh (Institute of Oceanography, National Taiwan University, Taiwan) au LOG intitulé :

Empirical dynamical modeling toward mechanistical understanding and forecasting of ecosystem dynamics

Date : 16 juillet 2018 à 10h30

Lieu : Wimereux salle de conférences MREN

Résumé :
Mechanistic understanding and forecasting are important for effective policy and management recommendations for ecosystems. Two classic approaches have been commonly used for this purpose : correlation analysis and parametric models using a set of assumed equations. For approach 1, we face the long-lasting problem that correlation does not imply causation. For approach 2, we encounter the difficulty that we do not know the exact set of equations and ecosystems are complex. Here, we show that the objective is better addressed using an alternative equation-free approach based on nonlinear state space reconstruction using time series data, known as Empirical Dynamic Modeling. This approach can distinguish causality from correlation and provide better forecasting skills for fish abundance in the complex environmental context, thus leading to mechanistic understanding. We demonstrate the methodology using Pacific sardines, Fraser River sockeye salmons, and Maizuru Bay fish community. These methods and applications can be used in general dynamical systems, such as ecosystem, climate, epidemiology, financial regulation, and much else.