Contrasting carbon cycle along tropical forest aridity gradients in West Africa and Amazonia

Huanyuan Zhang-Zheng (1) , Stephen Adu-Bredu (2) , Akwasi Duah-Gyamfi (2) , Sam Moore (1) , Shalom D Addo-Danso (3) , Lucy Amissah (3) , Riccardo Valentini (4) , Gloria Djagbletey (3) , Kelvin Anim-Adjei , John Quansah , Bernice Sarpong , Kennedy Owusu-Afriyie , Agne Gvozdevaite , Minxue Tang , Maria C Ruiz-Jaen , Forzia Ibrahim , Cécile A J Girardin (1) , Sami Rifai , Cecilia a L Dahlsjö , Terhi Riutta , Xiongjie Deng , Yuheng Sun (5) , Iain Colin Prentice (6, 7) , Imma Oliveras Menor (8, 1) , Yadvinder Malhi (1)

1 University of Oxford
2 CCST - CSIR College of Science and Technology
3 CSIR - Council for Scientific and Industrial Research [Ghana]
4 CMCC - Fondazione Centro Euro-Mediterraneo sui Cambiamenti Climatici [Caserta]
5 University of Groningen [Groningen]
6 Imperial College London
7 THU - Tsinghua University [Beijing]
8 UMR AMAP - Botanique et Modélisation de l'Architecture des Plantes et des Végétations

Tropical forests cover large areas of equatorial Africa and play a substantial role in the global carbon cycle. However, there has been a lack of biometric measurements to understand the forests’ gross and net primary productivity (GPP, NPP) and their allocation. Here we present a detailed field assessment of the carbon budget of multiple forest sites in Africa, by monitoring 14 one-hectare plots along an aridity gradient in Ghana, West Africa. When compared with an equivalent aridity gradient in Amazonia, the studied West African forests generally had higher productivity and lower carbon use efficiency (CUE). The West African aridity gradient consistently shows the highest NPP, CUE, GPP, and autotrophic respiration at a medium-aridity site, Bobiri. Notably, NPP and GPP of the site are the highest yet reported anywhere for intact forests. Widely used data products substantially underestimate productivity when compared to biometric measurements in Amazonia and Africa. Our analysis suggests that the high productivity of the African forests is linked to their large GPP allocation to canopy and semi-deciduous characteristics.

Mots clés: Tropical ecology

Domaines: Sciences de l'environnement

Huanyuan Zhang-Zheng, Stephen Adu-Bredu, Akwasi Duah-Gyamfi, Sam Moore, Shalom D Addo-Danso, et al.. Contrasting carbon cycle along tropical forest aridity gradients in West Africa and Amazonia. Nature Communications, 2024, 15, pp.3158. ⟨10.1038/s41467-024-47202-x⟩. ⟨hal-04562995⟩