Asbtract

Seagrass meadows provide essential ecosystem functions and services. They serve as nursery habitats for fish, and the structural complexity is a key factor influencing this function. Despite their ecological importance, seagrasses are being degraded worldwide at an alarming rate, leading to a significant loss of habitat structure. In response to this trend, restoration projects have been developed in recent years, aiming to recover both habitat structure and associated functions We assessed the recovery of habitat structure and the associated nursery function within a restored Posidonia oceanica meadow. Additionally, we conducted habitat selection experiments with two species, Diplodus annularis and Symphodus tinca, to evaluate if they actively select seagrass habitats based on structural complexity. Our results revealed that, despite the presence of some fish species in the restored area, neither the structural complexity nor the nursery function had fully recovered. In the choice experiments, both species exhibited a clear affinity for seagrass habitats over unvegetated areas, demonstrating their ability to actively selected habitats based on visual cues. However, the response in occupancy patterns to increasing seagrass complexity was species-specific.Understanding how juvenile fish respond to changes in seagrass habitat features is crucial for quantifying the nursery service provision and for identifying effective measures to accelerate the restoration process.