Prospects for long-term agriculture in southern africa: Emergent dynamics of savannah ecosystems from remote sensing observations

Hydro-climatic resilience is an essential element of food security. The miombo ecosystem in Southern Africa supports varied land uses for a growing population. Albedo, Leaf Area Index (LAI), Fractional Vegetation Cover (FVC), Solar-Induced chlorophyll Fluorescence (SIF), and precipitation remote-sensing data for current climate were jointly analyzed to explore vegetation dynamics and water availability feedbacks. Changes in the surface energy balance tied to vegetation status were examined in the light of an hourly albedo product with improved atmospheric correction derived for this study. Phase-space analysis shows that the albedo’s seasonality tracks the landscape-scale functional stability of miombo and woody savanna with respect to precipitation variations. Miombo exhibits the best adaptive traits to water stress which highlights synergies among root-system water uptake capacity, vegetation architecture, and landscape hydro-geomorphology. This explains why efforts to conserve the spatial structure of the miombo forest in sustainable farming of seasonal wetlands have led to significant crop yield increases. Grass savanna’s high vulnerability to water stress is illustrative of potential run-away impacts of miombo deforestation. This study suggests that phase-space analysis of albedo, SIF, and FVC can be used as operational diagnostics of ecosystem health.

Duke Scholars

Author Ana P. Barros Civil and Environmental Engineering