This dissertation investigates how sedimentation dynamics affect tropical estuarine seagrass ecosystems across spatial and temporal scales in Madagascar. While seagrass meadows provide ecological and socioeconomic services, they face ongoing global declines driven by natural and anthropogenic disturbances. To address major data gaps in the Western Indian Ocean bioregion, an interdisciplinary approach was applied across four Malagasy estuaries, combining multi-site field monitoring with Local Ecological Knowledge (LEK) and microcosm experimentation on Cymodocea rotundata and Halodule uninervis. Field surveys revealed strong spatial and seasonal heterogeneity, demonstrating that sedimentation and hydrodynamic processes—rather than rainfall alone—drive seagrass community structure and dynamics. Integrating community knowledge provided site-specific insights into disturbance regimes, local species preferences, and post-sedimentation recovery trajectories. Furthermore, experimental results confirmed that combined light impairment and sediment burial delay plant responses, highlighting that resilience is species-specific and grounded in functional trait flexibility. Overall, this research establishes a baseline for seagrasses in Madagascar and offers integrated socio-ecological frameworks to advance coastal conservation, monitoring, and restoration strategies under a changing climate.
ZMT - Leibniz Zentrum für Marine Tropenforschung
