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A project to protect and raise awareness of a coral found only in the Mediterranean—Cladocora caespitosa, a keystone reef-building species—while developing a replicable model for monitoring and conservation.
WHY THE PROJECT WAS CREATED
Cladocora-MedCoral is a pilot project to restore degraded areas of Cladocora caespitosa, where colonies occur in varying states of conservation. Commonly known as the cushion coral (or pillow coral in English), Cladocora caespitosa is a Mediterranean endemic and a keystone ecosystem engineer, capable of forming true underwater reefs that support countless animal and plant species and help reduce coastal erosion.
THREATS
In the Mediterranean, this species faces multiple threats that undermine its health. The main ones are: rising sea temperatures, which can trigger the loss of the symbiotic microalgae it depends on—leading to coral bleaching. Bleaching reduces the coral’s ability to feed and defend itself, makes colonies more vulnerable, and increases the risk of tissue necrosis; uncontrolled anchoring by tourist boats, which can shatter entire colonies; dredging; beach nourishment works; bottom trawling; and the spread of invasive algal species.
This project protects not only Cladocora caespitosa, but the entire ecosystem it helps build—and it can be replicated in other areas of the Mediterranean.
Where the projects take place
Some info about Cladocora Caespitosa
Cladocora caespitosa, commonly known as “pillow coral,” is an endemic coral of the Mediterranean Sea (found nowhere else in the world) that plays a crucial role in the construction of marine ecosystems.
Project phases
Research, Monitoring, and Outreach for the Future of Mediterranean Corals
Project proposals are developed together with research partners and are tailored to the specific sites where the species occurs.
CONSERVATION STATUS ASSESSMENT
Data collection and identification of signs of stress and degradation.
ONGOING MONITORING
Through the use of advanced methods to detect and assess coral health, we can take targeted, timely action.
ACTIVE PROTECTION
Direct actions to limit damage, promoting sustainable practices to halt degradation in the most vulnerable areas.
RESTORATION AND RECOVERY
Interventions using innovative techniques—such as nurseries and transplants—to restore vitality to damaged sites.
EDUCATION
Educational initiatives for local communities, schools, and visitors, designed to build a deeper understanding of why corals matter—and, more broadly, why protecting the sea is essential.
INFORMATION
Outreach actions for local communities highlighting the ecological and economic benefits of protecting biodiversity, encouraging public engagement and active participation through citizen science activities.
BEST PRACTICE
At the end of each project, in coordination with the research partners, we identify the data to be shared and the best practices that can be transferred to other sites—adapting them as needed.
Raffadella Giugni, Marevivo’s Secretary General, on Qasar Rai 1
The Marevivo Foundation’s “MedCoral Guardians” project is made possible through collaboration with outstanding partners, united by a shared goal: protecting marine biodiversity and restoring Cladocora caespitosa.
Ph. Julie Sferlazzo e Stefano Coco
The sea is life, let’s join forces to protect it.
Learn more about Cladocora
Cladocora Identity Card
Cnidaria Class: Anthozoa Subclass: Hexacorallia Order: Scleractinia Family: Cladocoridae Genus: Cladocora Species: Cladocora caespitosa
Description
Cladocora caespitosa is characterized by light yellow polyps, about 5 millimeters in diameter. Each polyp has a cylindrical shape with a crown of tentacles used primarily for defense against predators or to capture small food particles. The coral’s primary nutrition comes from symbiotic algae, called zooxanthellae. The calcareous skeleton that forms Cladocora caespitosa colonies is made of calcium carbonate, creating “pillow” formations. These colonies build three-dimensional underwater habitats that provide shelter and nourishment for many marine species.
Symbiosis with Zooxanthellae
The polyps of Cladocora caespitosa live in symbiosis with zooxanthellae, unicellular algae that reside inside the polyps and give them their characteristic light brown coloration. This symbiosis provides mutual benefits: the algae, protected within the colony, receive essential nutrients for photosynthesis, such as CO₂, phosphates, and nitrates derived from the polyps’ metabolism. In return, they assist the colony by eliminating metabolic waste and contributing to the construction of the calcareous skeleton. This close relationship is crucial for the coral’s growth and resilience but is extremely vulnerable to climate change and rising water temperatures. Changes in these factors can trigger the phenomenon of bleaching, which severely damages the coral and exposes it
Reproduction
Characteristics
Cladocora caespitosa is characterized by polyps with tentacles in multiples of six, sometimes arranged in multiple rows. The shape and size of colonies are influenced by depth, light availability, and water dynamics.
- Common forms: The typical hemispherical cushion shape develops in conditions of good illumination and strong hydrodynamism.
- Branched forms: More pronounced branching occurs in protected or deep environments, with minimal wave action and low light intensity.
- It is a long-lived species, with a generation lasting approximately 30 years.
- Locally, it can be abundant, forming scattered colonies or extensive banks that create submerged reefs.
- This species can adapt to significant climatic variations, an important trait in the Mediterranean, where surface water temperatures fluctuate widely throughout the year.
- It contributes to seabed stability and helps reduce the erosive force of waves and storms.
Habitat and Distribution
Cladocora caespitosa is a colonial species that grows on rocky or detrital seabeds from a few meters deep down to 35-40 meters, in environments exposed to strong currents as well as sheltered areas. Fossil specimens found in marine-origin rocks indicate its presence since the Pliocene (5.3–2.58 million years ago). It is found discontinuously throughout the Mediterranean and in some Atlantic locations (Morocco and Portugal). However, only in a few locations Cladocora c. forms beds (subspherical colonies of 10-30 cm, distinct from one another) or larger banks and submerged reefs form—structures reaching several decimeters in height and covering several square meters.
Role in the Ecosystem
Cladocora caespitosa is a true ecosystem engineer due to its crucial role in creating and maintaining complex marine habitats. By building coral reefs, it provides shelter, food, and safe breeding grounds for numerous animal and plant species, contributing to biodiversity and the stability of the marine ecosystem.
The bioconstructions it forms are not just structures but real biodiversity hotspots in the Mediterranean. Its calcareous formations, rich in crevices and cavities, host a wide variety of organisms, from red algae to bryozoans, creating essential conditions for marine life. In this context, Cladocora caespitosa acts as a cornerstone of the ecosystem, ensuring the survival of many other life forms.
Beyond its undeniable ecological value, it helps sequester excess CO₂ and plays a fundamental role in coastal protection by mitigating coastal erosion. Its coral structures absorb wave energy, helping to preserve shorelines and maintain coastal ecosystem dynamics.
Protection
- Annex II of the SPA/BIO Protocol of the Barcelona Convention
- Annex II of the Bern Convention
- IUCN Red List Conservation Status: Endangered
