Modelling responses of plant productivity to environmental change in the tropics

Abstract: Dr Lina Mercado is a senior lecturer at the University of Exeter. Her research focuses on the use of plant ecophysiological data to improve process understanding and to develop and validate dynamic global vegetation models (DGVMs). Lina works at multiple scales, from ecosystem to global level. Her presentation will focus on three pieces of work related to impact of i) thermal acclimation of photosynthesis, ii) nutrient limitation and iii) direct and diffuse radiation on tropical forest productivity using the Joint UK Land Environment Simulator, the land surface scheme of the Hadley Centre Earth System model.

Results show that i) if thermal acclimation of photosynthesis of tropical plants was possible, under predicted climate change plants will shift their optimal temperatures towards the new growth conditions allowing greater resilience of the tropical forest. ii) Accounting for N & P limitation to photosynthesis in tropical forest improves representation of spatial variability of gross primary productivity in the Amazon however it is not enough to represent spatial variability of stem growth indicating that there might be other processes influencing the large variation in observed stem growth rates found across the Amazon forest. Iii) Increases in diffuse radiation from biomass burning aerosol leads to increased photosynthetic uptake and seasonal changes in diffuse radiation might help explain the seasonal cycle of gross primary productivity of central amazon evergreen forest.