Séminaire ISPA Roderick Dewar, Australian National University, Canberra

Résumé : Tropical savannas – communities composed of a mixture of trees and grasses – are important ecosystems both for humans and for the global climate system. But a general predictive theory of the relative abundance of trees and grasses remains elusive. Modelling the detailed mechanisms of competition is hampered by the sheer complexity of the underlying biology. In this talk I’ll describe an alternative approach that successfully predicts the variation of tree and grass cover across a wide range of rainfall – from arid grassy savannas to wet tropical rainforest – using the rules of statistical mechanics, specifically the principle of maximum entropy. The approach also provides general insights into the relationships between ecosystem diversity and stability.