Determinants of above-ground carbon stocks and productivity in secondary forests along a 3000-m elevation gradient in the Ecuadorian Andes
Esteban Pinto, Francisco Cuesta, Antonella Bernardi, Mellisa Llerena-Zambrano, Álvaro J. Pérez, Masha T. van der Sande, William D. Gosling, Kevin S. Burgess
Abstract
Background Secondary montane forests, covering 30% of forested lands in the Andes, play a crucial role in mitigating the impact of carbon release. However, the mechanisms responsible for carbon sequestration in the above-ground biomass (AGC) of these forests are not well quantified.Aims Understanding the determinants of AGC dynamics in secondary forests along a 3000-m elevational gradient in the Andes to assess their mitigation potential.Methods We assessed how abiotic and biotic conditions, and past human disturbances were related to forest structure and composition, AGC stocks and productivity within sixteen 0.36-ha plots established in secondary forest stands of 30-35 years of age.Results Structural equation models revealed that changes in temperature conditions along the elevation gradient shaped leaf functional composition, which in turn controlled AGC dynamics. Productivity and temperature decreased with increasing elevation and decreased tree community leaf area. Disturbance legacy (Tree mortality) increased with competitive thinning and low soil fertility.Conclusions We show that temperature drives AGC dynamics via changing the functional trait composition. This highlights the importance of preserving these forests along elevation gradients and implies potentially strong future changes due to global warming.