Hatching Dynamics of Zooplankton Resting Forms under Desalinization Scenarios in a Restoring Mangrove Ecosystem

Mangrove restoration is essential for recovering the ecological functionality of degraded estuaries and reestablishing processes associated with coastal dynamics. Although these ecosystems are naturally adapted to salinity variations, changes in hydrological connectivity, such as water retention and reduced circulation, can compromise vegetation regeneration and the structure of aquatic communities. In this context, understanding the mechanisms that sustain biological resilience is essential for evaluating the effectiveness of management actions. However, the potential of sediment resistance banks (repositories of dormant zoobenthic stages capable of reactivating under favorable hydrological conditions) as indicators of hydrological restoration success remains poorly explored. These banks harbor the dormant zoobenthic community (the assemblage of zoobenthic organisms in a state of metabolic inactivity within the sediment), whose activation depends on favorable environmental conditions. In this study, we experimentally evaluated how salinity gradients modulate the hatching and community composition of organisms in resistance stages in a tropical mangrove undergoing restoration in Northeastern Brazil. Sediments from impacted, restoration, and preserved areas were incubated for 30 days to quantify the emergence potential of the zoobenthic community. Salinity reduction was associated with increased richness and activation of resistance stages, while values above 30 inhibited hatching. Salinities below 25 promoted significant increases in the density and diversity of emerging organisms. The hatched communities differed from those observed in the water column of the natural environment (in situ), indicating that the resistance bank represents a latent fraction of regional biodiversity. The results indicate that salinity acts as an environmental filter regulating the activation of dormant zoobenthic propagules and that its reduction during hydrological restoration reactivates the biological potential accumulated in the sediment, reflecting the ecological memory of the system and reinforcing its use as a tool for monitoring the structural and functional recovery of degraded mangroves over time.