Changes in climate and the environment are likely to have profound impacts on the diversity, nutrient and water cycles in tropical ecosystems. To better understand these processes and the response of tropical vegetation to the changing environment, there is a need for interdisciplinary studies focusing on the long-term biology, ecology, physiology and climatology of these ecosystems from local to regional spatial scales. This session has two main focuses, the Amazon rainforest and the savanna-forest transition across the tropics.
Tropical forest and savanna are highly heterogeneous in species composition, biomass and productivity, physical and chemical soil properties, and precipitation, as well as natural and anthropogenic disturbance regimes, such as blowdowns, fires and deforestation. Therefore, to understand the interaction between functioning and environmental change and to diagnose the future of tropical biomes and the feedbacks to global climate, it is important to build an integrative view of these processes that explicitly accounts for this spatial variability.
To advance this debate, we aim to gather an overview of recent research carried out in Amazonia and other tropical regions, focusing on heterogeneity of environmental variables and its influence on ecosystem functioning, and responses of ecosystem processes to environmental changes as it relates to observed diversity in tropical vegetation structure and function. The role of forest/savanna transitions in affecting the magnitude and rate of future climate change is also a key focus with a particular emphasis on the future of the Amazon Basin. Across a range of scales, we consider observational and modelling studies on carbon and nutrients (in particular, N and P) fluxes and the hydrological cycle, ecophysiological processes including responses to high temperature, drought and CO2. This includes spatially explicit studies of ecosystem dynamics, including productivity and species turnover, nutrient dynamics, disturbance impacts and rates, and detection of large-scale processes and environmental changes (including biome shifts).