I. Scientific background and context of the project:
According to the UNCCD’s Global Land Outlook 2 up to 40% of the planet’s land is degraded due to unsustainable land management and agricultural practices [1]. Land degradation refers to the process of losing biological or economic productivity and complexity of the dominant ecosystem –often resulting in significant shifts in land cover and a reduction in floral and faunal activity. This degradation of ecosystems and soils leads to exaggerated impacts of climate change and imbalances in the regional water cycle. As permeability in degraded lands is strongly reduced, heavy rains often lead to devastating floods [2] while groundwater recharge during those events is limited [3]. Loss of ecosystem diversity and function reduces the buffering effect that vegetation and healthy soils have in drought conditions [4, 5].
Sub-Saharan Africa has experienced the most severe land degradation in the world [6]; deforestation and conversion of grasslands to croplands accounting for most of this ongoing trend. Exacerbated by climate change and increasing intensity in flood and drought cycles, the expansion of degradation and decrease in land productivity are challenging livelihoods and food security [7]. Recognizing the crucial role of vegetation and ecosystem services in providing climate resilience, many large-scale efforts are underway to restore land and introduce and widen the use of sustainable and regenerative agricultural techniques [8, 9, 10].
Resilience Design is a methodology that was developed through humanitarian programs to increase climate resilience and food security by applying innovative and restorative agricultural approaches such as permaculture, agroecology and agroforestry [11]. Using a scalable approach working with natural patterns to improve water management and soil health, the Resilience Design method is used to build resilient biodiverse food systems that actively support water infiltration and retention and convert floods to food, prolonging even throughout challenging dry spells and flash droughts.
Over the coming years, several UN Organizations are building up large-scale Resilience Design projects across Uganda and Somalia impacting millions of livelihoods [8,9]. When scaled, the Resilience Design biodiverse food systems could not only increase the local water supply and residence time but have a significant impact on groundwater recharge and water cycling through evapotranspiration, and precipitation on a large scale creating regional microclimates that buffer climate extremes and stabilize the hydrology. By investigating regenerative agroecosystems and their influence on the regional to global water cycle, we fill a gap in our current understanding of the potential for ecosystem restoration and food system transformation on future water availability and climate change mitigation.
II. Research questions and objectives
From this background, we make the hypotheses that land regeneration and restoration have the potential to stabilize the terrestrial water cycle. Within this assumption, this doctoral project proposes to study the impact of regenerative agricultural practices on water cycle in Sub-Saharan Africa (Uganda). The PhD student work will answer the following questions:
1. What are the impacts of the resilience design on the local hydrology?
2. To what extent do the vegetation properties influence retention and infiltration of water in the soil?
3. How are both (1&2) linked to plant resilience (e.g., flash drought) and extending the growing season?
4. How are plant bionutrient levels linked to increased/stable water/moisture supply?
III. Methodology
a. Study site
The study site for this project is located in North Uganda, in the research center called Lok Neno located in the Palabek Refugee Settlement (6 ha). African Women Rising (AWR), with their world-class leaders in Resilience Design (RD) established a training, demonstration and research center where over the past two-years over 210 staff members of 54 global and regional humanitarian organizations from 16 countries have been trained in RD. This research site under a tropical climate receives around 1500 mm of precipitation per year. Hydrological infrastructures have been set up in the past 3 years for the purpose of this project and a forest based food production system is starting to get established onsite.
b. Research Plan:
The PhD student will be able to answer these questions through both in situ experiments and remote sensing analyses (from air drone and satellite data) comparing two sites: one with agroecological infrastructure and the other unmanaged.
1. In situ experiments:
• Measuring water resource through installation of soil moisture sensors, boreholes and weather station.
• Complementary in situ measurements of soil properties (hydraulic properties and other physico-chemistry properties) and vegetation properties (functional trait and nutrients) will take place in the second and third year to follow the humid and dry season.
2. Remote sensing analyses (proxydetection and teledetection):
• The remote sensing data will help quantify the spatial and temporal evolution of the water sources and sinks (precipitation, evapotranspiration, soil moisture, above ground biomass, vegetation water content, water use efficiency, air temperature, land surface temperature, land use…) across the two sites.
• A drone will be used to follow several parameters related to vegetation and soil health (NDVI and other vegetation indices as well as soil moisture and soil organic carbon derived from multispectral data, above-ground biomass from LIDAR observations, surface temperatures from thermal emissivity data).
• Satellite remote sensing data will be used to derive the same quantities and provide a broader temporal and spatial context. Example missions include ECOSTRESS, Landsat (surface temperature and evapotranspiration), SWOT (surface water height and extent), GEDI (above-ground biomass), GPM (precipitation), Sentinel-1 & Sentinel-2 (vegetation health and soil moisture).
IV. Outcomes
This project will provide several benefits such as:
● Creating an international research consortium between the US, France and Sub Saharan Africa to establish stakeholder-driven science on the impact of agroecosystems on the water cycle.
● Amplify knowledge generation and education around the link between regenerative agriculture and building climate resilience and food security.
● Quantify the co-benefits of scaling regenerative agriculture on the global water cycle including links between water storage capacity, vegetation and soil health, nutrient density, and carbon sequestration.
V. Host laboratory
The PhD student will be hosted in the University of Tours, UMR 7324 CITERES (minimum 4 month per year) and the University of Gulu (Faculty of Agriculture and Environment). Field trips in the research center of Lok Neno in Uganda will be organised for in situ experiments. The University of Tours will provide a full grant (through a French working contract) after an oral evaluation of the candidate (in June).
VI. Supervisors
Main supervisors will be Dr. Séraphine Grellier assistant professor from CITERES, University of Tours in France and Dr. Kato Stonewall Shaban, senior Lecturer and Deputy Dean for Faculty of Agriculture and Environment at the Gulu University in Uganda.
Two main investigators of the project will also take part in the supervision: Dr. Carmen Blackwood (Earth Rise LLC) and Warren Brush (Resilience Design Consultants) from USA.
VII. Required Knowledge and Skills
The candidate must hold a master’s degree in agronomy, soil science, or ecology. He/she should have a good knowledge of soil science and ecology. Complementary knowledge in remote sensing analyses and hydrology will be appreciated. The candidate should have an interest in fieldwork and transdisciplinary work. The project requires solid experience in statistics and data processing, as well as a good expertise of the English language (reading, writing, and speaking). Knowledge of the French language will be a plus.
VIII. Application
A CV and motivation letter in English shall be sent as soon as possible and before the 21st of April 2025 to Dr. Séraphine Grellier seraphine.grellier@univ-tours.fr, to Dr. Kato Stonewall Shaban s.kato@gu.ac.ug and to Dr. Carmen Blackwood carmen.blackwood@earthrise.la
The PhD will start in September or October 2025.
References
[1] United Nations Convention to Combat Desertification, 2022. The Global Land Outlook, second edition. UNCCD, Bonn.
[2] Balgah, R.A.; Ngwa, K.A.; Buchenrieder, G.R.; Kimengsi, J.N. Impacts of Floods on Agriculture-Dependent Livelihoods in Sub-Saharan Africa: An Assessment from Multiple Geo-Ecological Zones. Land 2023, 12, 334. https://doi.org/10.3390/land12020334
[3] Ilstedt, U., Bargués Tobella, A., Bazié, H. et al. Intermediate tree cover can maximize groundwater recharge in the seasonally dry tropics. Sci Rep 6, 21930 (2016). https://doi.org/10.1038/srep21930
[4] Fisher, J. B., et al. (2017), The future of evapotranspiration: Global requirements for ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources, Water Resour. Res., 53, 2618–2626, doi:10.1002/2016WR020175.
[5] Grange, G.; Finn, J.A.; Brophy, C. Plant diversity enhanced yield and mitigated drought impacts in intensively managed grassland communities. J. Appl. Ecol. 2021, 58, 1864–1875.
[6] Coppus, R. 2023. The global distribution of human-induced land degradation and areas at risk. SOLAW21 Technical background report. Rome, FAO. https://doi.org/10.4060/cc2843en
[7] Krishnamurthy R, P.K., Fisher, J.B., Choularton, R.J. et al. Anticipating drought-related food security changes. Nat Sustain 5, 956–964 (2022). https://doi.org/10.1038/s41893-022-00962-0
[8] RESTORE Restoring the Riverine Eco-Systems for Climate Adaptations – https://www.fao.org/somalia/news/detail-events/ar/c/1673410/
[9] URRI Uganda Refugee Resilience Initiative – https://uganda.um.dk/en/danida-en/upside-uganda-programme-for-sustainable-and-inclusive-development-of-the-economy/urri -call-for-proposals
[10] Great Green Wall Accelerator – https://www.unccd.int/our-work/ggwi/great-green-wall-accelerator
[11] Mottram, A., Carlberg, E., Love, A., Cole, T., Brush, W., and Lancaster, B. 2017. Resilience Design in Smallholder Farming Systems: A Practical Approach to Strengthening Farmer Resilience to Shocks and Stresses. Washington, DC: The TOPS Program and Mercy Corps.
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