Modelling fires as pulses in tree/grass interactions: study of long-term impact in forest-savanna dynamical systems

Tchuinte Tamen Alexis, Dumont Yves, Bowong Samuel, Tewa Jean Jules, Couteron Pierre. 2015. Modelling fires as pulses in tree/grass interactions: study of long-term impact in forest-savanna dynamical systems. Biomath Communications, 2 (1), Résumé, 1 p. International Conference on Mathematical methods and Models in Biosciences and Young Scientists School, Pretoria, Afrique du Sud, 12 Juillet 2015/17 Juillet 2015.

https://doi.org/10.11145/475

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Url - éditeur : http://www.biomathforum.org/biomath/index.php/conference/article/view/475

Résumé : It is usually admitted that fires play an important role in tree-grass interactions in savanna ecosystems. In this talk, we present a model of tree-grass dynamics using impulsive differential equations, considering fires as discrete events [1]. This framework allows us to carry out a comprehensive qualitative mathematical analysis that revealed more possible outcomes than the analogous continuous model [2]. We investigated local and global properties of the equilibria and show that various states may co-exist. Though fire periodicity may drive the system to different and abrupt shifts between vegetation, we also show that direct shading of grasses by trees, through a facilitation/competition parameter, is an influential process too, leading to bifurcations. Finally, using a suitable numerical approach [3], we carried out numerical simulations related to three main climatic zones, observable in Central Africa, to illustrate our theoretical results. (Texte intégral)

Mots-clés Agrovoc : savane, forêt tropicale, incendie de forêt, herbage, arbre d'ombrage, compétition biologique, dynamique des populations, modèle mathématique, méthode statistique

Mots-clés géographiques Agrovoc : Afrique centrale

Mots-clés libres : Mathematical modelling, Savanna, Fire, Impulsive differential equation, Periodic equilibrium, Nonstandard finite difference method

Classification Agris : U10 - Informatique, mathématiques et statistiques
K01 - Foresterie - Considérations générales
F40 - Écologie végétale

Champ stratégique Cirad : Axe 6 (2014-2018) - Sociétés, natures et territoires

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