Climate models predict a range of changes in the tropical forest regions, including increased frequency of extreme climatic events, increased temperatures and reduced rainfall intensity. These changes are directly related to increasing atmospheric CO2 concentration due to human activity and can directly influence the functioning of tropical forests. Therefore, assessing tree growth response to climate is fundamental for understanding critical thresholds and alterations on forest productivity. This is relevant because wood production is the main way carbon is fixed in forest ecosystems to constitute the biomass stock. The response of tropical tree growth to changing climate could drive a change in the direction of the carbon fluxes between the biosphere and the atmosphere transforming tropical forest ecosystems into a source of carbon. To refine our understanding on the impacts of global climate change on tropical forests, the general objectives of this project are to: (i) improve the knowledge of seasonal dynamic of net primary production in tropical forests, (ii) produce the first map of seasonal NPP at a pantropical scale as a function of site and climate characteristics and finally (iii) assess net primary production responses to climate change. This will be achieved by conducting a metanalysis combining information on intrannual tree growth measurements for 27 pantropical forest sites with their correspondent monthly climate data and satellite derived vegetation indices to calibrate, parameterize and validate a pantropical model of biomass production. Specifically, we aim to (i) analyze if there is a coherence between the biological mechanisms observed from field and from satellite measurements, (ii) determine the relative contribution of climate and environmental site characteristics on the seasonal biomass production and (iii) quantify changes in tropical forest functioning, in terms of the responses of carbon fluxes to climate change using the CMIP5 climate scenarios. The results of this project will provide a novel pantropical description of the carbon cycle in tropical forest ecosystems at a seasonal time scale as a function of site and climate characteristics and will contributed to determining the consequences of climate change on biomass stocks and fluxes in tropical forested regions. These results are likely to be of great importance for future reports of the Intergovernamental Panel for Climate Change (IPCC) and the Brazilian Panel for Climate Change, as well as for supporting environmental planning in tropical regions aiming to mitigate climate impacts, maintain carbon stocks and protect biodiversity and ecosystems services.
News published in Agência FAPESP Newsletter about the scholarship: