Abstract

Savanna grasslands constitute approximately 20% of global terrestrial ecosystems, providing critical ecosystem services including carbon sequestration, biodiversity conservation, and pastoral livelihoods. However, degradation from overgrazing, fire suppression, and woody plant encroachment threatens these systems globally. This study investigated the effectiveness of managed herbivore grazing practices for restoring degraded savanna grasslands across 18 sites in East Africa over a 36-month period. A randomized controlled experimental design compared four grazing management regimes: continuous grazing at moderate stocking density, rotational grazing with 21-day rest periods, adaptive multi-paddock grazing with variable stocking densities, and complete livestock exclusion as control. Vegetation assessments quantified grass biomass, species diversity, functional group composition, and woody plant density at six-month intervals across 216 permanent monitoring plots. Soil samples analyzed organic carbon content, bulk density, infiltration rates, and aggregate stability. Results demonstrated that adaptive multi-paddock grazing achieved superior outcomes across multiple metrics, increasing perennial grass cover from baseline 28±8% to 67±12% compared to 31±9% in exclusion controls. Total herbaceous biomass under adaptive grazing reached 4,850±780 kg/ha dry matter, significantly exceeding rotational grazing at 3,420±650 kg/ha and continuous grazing at 2,180±520 kg/ha. Species diversity, measured by Shannon index, improved from 1.8±0.4 to 3.2±0.6 under adaptive management versus minimal change in controls. Soil organic carbon increased by 42% under adaptive grazing compared to 18% under exclusion. Woody plant recruitment decreased by 68% in grazed treatments versus 12% in ungrazed areas. Economic analysis revealed that adaptive grazing generated livestock productivity gains of 35-48% alongside ecosystem restoration benefits, achieving positive net present values within 24 months. This research demonstrates that appropriately managed herbivore grazing, particularly adaptive multi-paddock systems mimicking natural disturbance regimes, provides effective restoration tools surpassing passive protection approaches while maintaining productive land use and supporting pastoral livelihoods.