Invasive macrophytes in a marine reserve (Columbretes Islands, NW Mediterranean): spread dynamics and interactions with the endemic scleractinian coral Cladocora caespitosa

Regional genetic differentiation among populations of Cladocora caespitosa in the Western Mediterranean

“…Past geological and ecological events, together with the corals' sexual reproductive traits and their relation to oceanographic and geomorphologic processes may explain the present genetic structure of Cladocora caespitosa. Our results suggest that the studied populations are highly dependent on self-recruitment, likely enhanced by the eggretention mechanisms of this species (Kružic et al 2008a), all of which is reflected in this species' the distribution and recruitment patterns (Kersting and Linares 2012;Kersting et al 2014b). On the other hand, the genetic connectivity among the populations, even if generally low, seems to be related to sporadic dispersal events through regional surface currents linked to the spawning period.…”

“…This is the first study dealing with the population genetics of C. caespitosa, a relict species in the Mediterranean Sea. The high self-recruitment levels and the low and probably intermittent connectivity found, together with the slow dynamics of the species (Kersting et al 2014b), may indicate a reduced recovery potential from the recurrent heat wave-induced mortalities that are affecting this species (Kersting et al 2013a). The results obtained will promote conservation plans for the populations of this coral.…”

“…The ability of marine populations to resist and recover from environmental disturbances depends in part on population connectivity and recruitment processes, which contribute to the addition of new individuals to populations and therefore to population resilience of marine organisms (Caley et al 1996), particularly corals (Adjeroud et al 2007) including C. caespitosa in the Mediterranean (Kersting et al 2014b). To improve our knowledge on the recovery potential of this bioconstructive species, a better understanding of the resilience of its populations is needed.…”

“…The egg-retention mechanisms described for this coral may increase self-recruitment, as evidenced by the distribution and recruitment patterns of some of its populations (Kersting and Linares 2012;Kersting et al 2014b). Therefore, it is hypothesized that populations of C. caespitosa in the Western Mediterranean basin may display high levels of self-recruitment, showing different levels of genetic differentiation between them.…”

Overview of the conservation status of Mediterranean anthozoa

“…Moreover, the habitat of C. caespitosa is being increasingly invaded by several invasive algal species such as Caulerpa cylindracea and Lophocladia lallemandii , Kersting et al 2014. Even though there is no evidence of lethal effects caused by the algal invasion on the adult coral colonies, impacts on other stages of C. caespitosa life cycle (e.g., recruitment) are happening and synergies with other stressors like warming are very likely.…”