Population dynamics of temperate corals in a changing climate

In contrast with the number of studies on tropical species, analyses of the variation of growth parameters with environmental variables in temperate areas are very scarce. Notwithstanding the importance of obtaining information on coral population dynamics, few studies have quantifi ed demographic parameters of scleractinian corals, partly because of the processes of fragmentation, fusion and partial colony mortality, which cause corals of similar size to be of widely different ages, thus distorting the age-size relationships. Available literature on growth and population dynamics of natural populations of temperate scleractinians is reviewed in the present work. As general trends, it seems that: (1) solitary species have a defi nite growth pattern, in contrast with colonial species; (2) symbiotic species are more sensitive to increasing temperatures and more vulnerable to global warming; (3) non-symbiotic species are more tolerant to increasing temperature, but may be negatively affected by the indirect effects of increasing solar radiation; and (4) even if the energy resulting from photosynthesis may increase as a consequence of ocean acidifi cation, the growth and abundance of symbiotic corals seem to be negatively affected by acidifi cation and the negative response of non-symbiotic corals is expected to be even stronger.