A normal form for excitable vegetation dynamics
Carles Martorell (Advisor: Damià Gomila)
Master Thesis (2021)
In this work we study excitable dynamics related with vegetation ecosystems. In particular, we are interested in a model of Posidonia oceanica seagrass which motivates the dynamical system studied in this project. This model introduces an autotoxicity mechanism, by means of sulfide production due to decomposition of the seagrass, which plays a negative feedback role in the dynamics. In this way, this model can display interesting and sophisticated phenomena such as spatio-temporal patterns. From a Dynamical Systems point of view, all these phenomena are related with a rich bifurcation diagram. We propose a simple dynamical system which presumably reproduces such bifurcation diagram. In particular, we pay attention on the excitable region appearing close to the Takens-Bogdanov point. We study the existence of excitable travelling pulses in this region when a diffusion term is added in the spatially extended model.