Charla invitada: The savanna problem from a Statistical Physics point of view

FEDERICO VAZQUEZ

Huelva

Conferencia; FisEs 2009; 2009

What is unique about savannas that allows the coexistence of trees andgrasses? What are the factors that govern that coexistence?Despite many scientific efforts during the last decades, thesequestions are still open.  Recent empirical work suggests thattree-tree competition and external forcing like fire and varyingweather conditions are key factors that regulate savanna dynamics.  Totackle the combined effects of these mechanisms from a StatisticalPhysics point of view, we develop a minimalistic and analyticallytractable stochastic model, which is a variant of the Contact Process.The model exhibits a transition from grassland to tree-grasscoexistence, whose nature depends on the values of the internalparameters.  We also study the spatial structure of tree distributionand characterize the mechanisms leading to clustering.