Nutrient-cycling mechanisms other than the direct absorption from soil may control forest structure and dynamics in poor Amazonian soils

Oriol Grau (1) , Josep Peñuelas (1) , Bruno Ferry (2) , Vincent Freycon (3) , Lilian Blanc (3) , Mathilde Desprez (4) , Christopher Baraloto (4) , Jérôme Chave (5) , Laurent Descroix (6) , Aurélie K. Dourdain (4) , Stéphane Guitet (7) , Ivan A. Janssens (8) , Jordi Sardans (1) , Bruno Hérault (4)

1 CREAF - Centre de Recerca Ecològica i Aplicacions Forestals
2 ENGREF - Ecole Nationale du Génie Rural, des Eaux et des Forêts
3 UPR Forêts et Sociétés - Forêts et Sociétés
4 UMR ECOFOG - Ecologie des forêts de Guyane
5 EDB - Evolution et Diversité Biologique
6 ONF Guyane, Réserve de Montabo
7 UMR AMAP - Botanique et Modélisation de l'Architecture des Plantes et des Végétations
8 UA - University of Antwerp

Tropical forests store large amounts of biomass despite they generally grow in nutrient-poor soils, suggesting that the role of soil characteristics in the structure and dynamics of tropical forests is complex. We used data for >34 000 trees from several permanent plots in French Guiana to investigate if soil characteristics could predict the structure (tree diameter, density and aboveground biomass), and dynamics (growth, mortality, aboveground wood productivity) of nutrient-poor tropical forests. Most variables did not covary with site-level changes in soil nutrient content, indicating that nutrient-cycling mechanisms other than the direct absorption from soil (e.g. the nutrient uptake from litter, the resorption, or the storage of nutrients in the biomass), may strongly control forest structure and dynamics. Ecosystem-level adaptations to low soil nutrient availability and long-term low levels of disturbance may help to account for the lower productivity and higher accumulation of biomass in nutrient-poor forests compared to nutrient-richer forests.

Mots clés: tropical rain forests; forest ecosystem

Mots clés: forêt tropicale humide; écophysiologie forestière; guyane française; fertilité chimique; écosystème forestier

Domaines: Sciences du Vivant [q-bio]

Oriol Grau, Josep Peñuelas, Bruno Ferry, Vincent Freycon, Lilian Blanc, et al.. Nutrient-cycling mechanisms other than the direct absorption from soil may control forest structure and dynamics in poor Amazonian soils. Scientific Reports, 2017, 7, pp.45017. ⟨10.1038/srep45017⟩. ⟨hal-01606170⟩