Savanna Soil Carbon: investigating biological climate resilience

Savanna ecosystems occupy 20% of the Earth's land surface and are characterized by open canopied mixed woodland-grassland with seasonal rainfall in tropical and sub-tropical regions. They are also reservoirs of globally important biodiversity and carbon that are strongly influenced by the combined effects of grazing, fire and climate. Savannas are critical for human livelihoods and wellbeing, with over 1 billion people reliant on resources or services that these landscapes provide. These include the provision of food, fuel and fibre from natural and managed savanna ecosystems. The co-evolution of savannas and humans has occurred over 200,000 years.

Soils underpin the delivery and sustainability of the form and function of these environments with soil biotic communities actively regulating biome scale vegetation dynamics, greenhouse gas emissions, and carbon sequestration. These ancient and valuable systems are, however, under pressure from increasing human activity and over-exploitation and changes in fire and climatic regimes. Together these drivers have the capacity to significantly alter savanna biodiversity and biogeochemical function with implications for dependent human welfare and happiness. Specifically, there is considerable uncertainty regarding the potential individual and interactive impacts of these phenomena on the biological and biogeochemical resilience of the underlying soils.

The aim of this PhD research will be to improve understanding of the individual and interactive effects of grazing, fire and climate change on savanna soil biology, carbon biogeochemistry and resilience to future disturbance. Research will be focused on savanna ecosystems in South Africa that typify sub-tropical seasonal drylands found across the planet. Specific objectives and activities will include: 1. To determine the variability in soil properties across savanna degradation gradients. 2. To examine the effects of grazing/fire/climate interactions on soil properties and functions in the field. 3. To test the biotic and functional resilience of savanna soils to climate stress and physical disturbance.

Approach - A range of plant-soil field, experimental and laboratory techniques will be used in collaboration with researchers from University of Witwatersrand, and Pretoria University in South Africa, the UKCEH at Lancaster and University of Liverpool.

Student training will ensure specific research and transferable skills development that include; soil ecology and biogeochemistry, microbial molecular techniques, greenhouse gas sampling and analyses, isotope science, experimental design, statistics, scientific writing, research presentation/publication, project management, financial oversight and review, team working, advanced independent learning, people and time management, networking, international research.