Ecological Restoration of Mangrove Forests: Early Ecological Responses to Hydrological Restoration in Eastern Africa

Mangrove forests in northern Mozambique were impacted by human and natural pressures that caused channel blockage, permanent flooding, and tree die back. To address the issue, hydrological restoration was carried out in August 2024, excavating 6.88 km of canals with impact in 38 ha of degraded mangrove. This study reports on the monitoring results carried out 4 and 10 months later. Site salinity approached optimal levels for mangrove growth by dropping 56% in high salinity areas, and increasing above 100% in freshwater invaded areas. The intervention also homogenized the previously distinct upper, middle and lower zones (Dunn Post-Hoc: p > 0.05). Moreover, seedling density increased from 57.1±44.1 to 4864±1778.6 seedlings/ha; and regenerating species went increase in number (1 to 3 in middle zone; and 0 to 3 in lower zone). More regenerating classes (63:1:1 in upper, 11:1:0 in middle and 6:1:0 in lower) and die back of competing species Juncus kraussii and Cyperus articulates was also recorded. These changes result from the improved tidal flow and general habitat conditions in the restored site. This restoration offers a model for scaling restoration efforts across the region, where ecological restoration remains underrepresented in many mangrove restoration initiatives.