Cladocora caespitosa and Cystoseira spp.: description of a new habitat and interactions coral/algae in mixed assemblages

• Autor(a) principal: Fita, Alèssia Pons
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/15090
• topic: Cladocora caespitosa; Cystoseira; Interactions; Competition; Habitat; Corals

Zooxanthellate corals and benthic macroalgae that overlap in the same habitat compete for limiting resources such as light and space and have physical and chemical clues to outcompete each other. There is a huge amount of literature based on coral-algal interactions that endorse the general assumption about the negative outcomes on corals once the algae proliferate due to increased nutrient loads or decreasing herbivory rates. Here we have discovered and characterized a new and unique Mediterranean habitat where the reef-building coral Cladocora caespitosa and erect seaweeds of the order Fucales (Cystoseira s. l.) coexist. In this new habitat Cladocora caespitosa reaches 34% cover and densities of Cystoseira s. l. (mainly Treptacantha ballesterosii) are much higher than reports from other sites provided by different authors. Interestingly, abundances of Treptacantha ballesterosii and Cladocora caespitosa show a positive relationship suggesting that some kind of facilitation mechanism is taking place. Comparing these Cladocora-Cystoseira s. l. relationships with other places where these taxa coexist, reveals that these relationships are species- and site-specific, although most of them are neutral or positive. Despite the mechanisms mediating coral-algae interactions are being poorly understood, description of positive to neutral long-lasting relationships between these principal Mediterranean habitat-formers challenges the expected competition for space between corals and macroalgae.