Map of the Week – Coralligenous Habitats
Across the 46,000-km long coastline, the Mediterranean coastal seascape hosts as much as 18% of all known marine species—within which 20-30% are endemic—and contributes to about 30% of the global tourism [1,2]. However, the unique marine biodiversity of the Mediterranean Sea is facing growing threats from multiple human pressures, leading to degrading ecosystem functioning [2,3]. As the summer vacation season approaches, the allure of sandy beaches, azure waters, and warm sunshine calls us to the coast. Amidst the excitement, let's not forget our role as responsible tourists in preserving our charming but delicate marine ecosystems.
The coralligenous habitat is recognised as the second-most important benthic ecosystem in the Mediterranean, after Posidonia oceanica meadows (an endemic species of seagrass), in terms of biodiversity and productivity [3]. It is estimated to harbour approximately 1700 species, encompassing 1300 algae, 1200 invertebrates, including the renowned Mediterranean red coral (Corallium rubrum), and over a hundred fish species [4]! Bioconstructions such as coralligenous outcrops and maërl beds are typical Mediterranean underwater seascapes, comprising coralline algal frameworks that grow in dim light conditions. They are the result of the building activities of algal and animal constructors, counterbalanced by physical, as well as biological, eroding processes. Zoom into the Map of the Week and have a look at the probability of coralligenous occurrences along the Mediterranean coastline!
Coralligenous and mäerl habitats are highly important in the Mediterranean Sea due to their ecological and socio-economic significance. They do not only act as a carbon sink and biodiversity hotspots, but also supply commercially important fish species as well as contribute to marine tourism and coastal economies. Given their vulnerability to various threats, it is crucial to protect and care for our vibrant marine biodiversity while we enjoy various beach and sea activities:
- Snorkel and dive with care, learn to minimise our environmental impact;
- Understand coastal tourism and what we can do to reduce damages;
- Learn about Natura 2000 sites with the Natura 2000 viewer. The Natura 2000 network includes sites protected under the Birds Directive and the Habitats Directive, in which reef is listed [5].
The data in this map are provided by EMODnet.
[1] https://www.unep.org/unepmap/resources/factsheets/blue-economy
[2] https://www.eea.europa.eu/soer/2015/countries/mediterranean
[3] https://www.nature.com/articles/s41598-018-20297-1
[4] https://rac-spa.org/coralligenous
[5] https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A01992L0043-20130701