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Communication dans un congrès

Spatial ecological processes allow tree-grass coexistence in savannas despite repeated fires

Abstract : Repeated fires could prevent tree encroachment in the grass stratum of savannas. However, there are some ecological mechanisms that allow invasion of trees in moist grasslands and eventually, when trees reach high density, prevent fire spread. To better understand the interplay between fire and tree encroachment, we developed a spatially explicit individual-based model representing the interactions between grass, fire spread and trees We considered three different sets of tree life history traits characterizing three types of trees, namely resprouters, resisters, and avoiders Resprouters are able to resprout after their aboveground biomass is burned, resisters can resist fire due to a thick bark developed in early age, avoiders are very fire vulnerable but tend to grow fast. The results of the model show that these three strategies allow tree invasion in the grass stratum despite repeated fire. Resprouters form a population of gullivers (alive trees whose aboveground biomass is burned) persisting repeated fires, resisters could grow slowly from year to year despite fires, and avoiders form clusters where fire cannot spread The three simulated tree strategies demonstrated that, in savannas, spatial interactions between trees, grass and fire spread are able to allow tree invasion into the grassland stratum despite repeated fires, and allow tree-grass co-existence in savannas for a transient period, before the complete canopy closure We remark that the inclusion of space in the model is fundamental in achieving our results, and spatial interactions in savannas are among the mechanisms allowing tree-grass coexistence.
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Communication dans un congrès
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https://hal.inrae.fr/hal-02735409
Déposant : Migration Prodinra <>
Soumis le : mardi 2 juin 2020 - 15:59:44
Dernière modification le : lundi 14 décembre 2020 - 15:46:14

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  • HAL Id : hal-02735409, version 1
  • PRODINRA : 429585

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Francesco Accatino, Carlo de Michele, Kerstin Wiegand, David Ward. Spatial ecological processes allow tree-grass coexistence in savannas despite repeated fires. European Conference of Tropical Ecology 2017, Society for Tropical Ecology (Gesellschaft für Tropenökologie). Göttingen, DEU., 2017, Bruxelles, Belgium. 520 p. ⟨hal-02735409⟩

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