Grant: Discovery Grants Program - Individual

Dryland regions cover ~40% of the terrestrial surface and support over a third of the world's population, ~90% of whom live in developing countries. Drylands are experiencing degradation and desertification from more intense droughts, changes in the frequency and intensity of rainfall, and land management. Dryland ecosystems play a key role in many interactions between different parts of the earth system. For example, drylands are hotspots of land-atmosphere interactions, meaning that land surface properties such as soil moisture and vegetation activity exert a strong influence on surface energy and water fluxes, which in turn affects local to regional scale precipitation. Drylands are also thought to play a dominant role in year-to-year variability of global terrestrial carbon cycling and long-term capacity of the land to store carbon. Understanding which regions, and which processes, are driving global carbon cycle variability and long-term carbon storage is crucial for predicting the level of anthropogenic CO2 emissions that will remain in the atmosphere, and thus the allowable emissions that we can afford to remain under a given rise in global temperature. However, despite their importance in the earth system, dryland ecosystem processes remain poorly understood and not well modelled. As a result of our lack of process understanding and model predictive capacity, many questions about dryland ecosystem responses and feedbacks to current and future climate and environmental change remain unanswered. To answer these questions, we must improve our understanding of dryland processes - i.e., the biological and physical processes underpinning dryland vegetation, biological soil crust (biocrust) and soil functioning - and their influence on carbon and water cycling. We must then ensure that our knowledge of these processes is implemented into global, process-based terrestrial biosphere models that form the land component of the earth system models used in climate change projections. My proposed program of research will use a wide range of existing field, satellite, and experimental manipulation data to: a) improve our understanding of dryland ecosystem vegetation, biocrust, and soil processes; b) develop new mathematical functions of key dryland processes and ensure they are accurately implemented into global scale models; and c) quantify and reduce uncertainty in the newly developed models via a rigorous statistical data assimilation framework. We will then use the improved, data-constrained models to better understand how dryland ecosystem processes interacting across scales will be impacted by climate change, and how changing dryland ecosystem structure and functioning will feedback to changes in climate. This work will help us with our long-term goal of building reliable models that can be used for exploring climate change adaptation scenarios to help improve the livelihoods and survival of some of the most vulnerable people on our planet.