Fire, resprouting and variability: a recipe for grass–tree coexistence in savanna

摘要: Summary 1 Savanna ecosystems are characterized by the codominance of two different life forms: grasses and trees. An operational understanding how these forms coexist is essential for savanna function predicting its response to future environmental change. 2 The existing model, which proposes that trees a separation rooting niches, not supported recent empirical investigations. Our aim was define an alternative mechanism grass–tree coexistence in ecosystems. The model we have built concentrates on history–disturbance interactions between trees. 3 The demonstrates wide range conditions, exhibits long periods slow decline adult tree numbers interspersed with relatively infrequent recruitment events. Recruitment controlled rainfall, limits seedling establishment, fire, prevents into size classes. Decline result continuing, but low levels, mortality. Both aspects dynamics consistent established non-equilibrium (the storage effect). 4 A sensitivity analysis indicated data resprouting ability, stem growth rates relationship establishment wet season drought both conditions possible change. 5 Our suggests requires consideration long-term effects demography, rather than fine-scale resource competition physiological performance.