Savannas can Functionally Turn into Forests in the Amazonia/Cerrado Transition
Palavras-chave:Cerradão , Dense Cerrado, Marimon-Hay, decomposition constant k, root mat
Adjacent forest formations are ecotones that can reveal changes in the vertical structure of tropical biomes e.g. , Cerrado (brazilian Savanna). Litterfall is a metric that shows some of these alterations. Thus, we investigated key functional aspects of a Cerradão (savanna forest) and a savanna (Dense Cerrado) in the Amazonia/Cerrado transition. We evaluated the litter layer, leaf decomposition, and root mat to verify to what extent these parameters are related to ecosystem functioning of the two distinct formations, savanna, and forest. The integrated litter layer/root mat system is the main pre-condition for ecosystem functioning and trophic balance of tropical forests on dystrophic soils. The litter layer, root mat, and leaf decomposition rates were very similar in both ecosystems, including carbon release from the litter layer, despite the differences in floristic and structure of both vegetations. These similarities indicate densification of the adjacent Cerrado with a pre-structuration of a forest-like ecosystem functioning, mainly due to the no fire event. Our findings suggest that savanna ecosystems on dystrophic soils of the Amazonia/Cerrado transition have high potential to establish the trophic functional conditions to support a forest community in the absence of fire and climate changes. As long as the current climate does not change to drier and hotter conditions (e.g. , increased El Niño anomalies), ecological succession can be triggered and savannas can functionally turn into forests, with an increase in carbon stocks of the ecosystem.
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