Marine Ecosystems Restoration – Madeira Case Study

Historically, the shallow, rocky reefs of Madeira had been dominated by macroalgae, creating a habitat of colorful seaweeds that provide shelter, food, and a complex structure to many marine organisms, including fish, crabs, and sea snails. Due to a variety of natural, anthropogenic, and climate change-related stressors, seaweed populations have declined, resulting in the degradation of the ecosystem. Additionally, increased sea urchin populations have led to overgrazing, leaving barren seascapes behind.

To combat these sea urchin barrens, restoration actions at Madeira focus on (1) the reduction of grazing pressure when sea urchin populations are above a critical threshold and (2) the transplantation of lab-grown algae to help the recovery of local macroalgae populations. Four restoration sites were selected on the south side of the island, including two sites inside the Garajau Partial Nature Reserve. All restoration sites are being closely monitored by researchers using scientific diving to perform underwater visual surveys and a citizen scientist initiative involving local diving centers using the Dive Reporter App.