The ecology and structure of many tropical coral reefs have been markedly altered over the past few decades. Although long‐term recovery has been observed in terms of coral cover, it is not clear how novel species configurations shape reef functionality in impaired reefs. The identities and life‐history strategies of the corals species that recover are essential for understanding reef functional dynamics. We used a species identity approach to quantify the physical functionality outcomes over a 13 year period across 56 sites in the Mexican Caribbean. This region was affected by multiple stressors that converged and drastically damaged reefs in the early 2000s. Since then, the reefs have shown evidence of a modest recovery of coral cover. We used Bayesian linear models and annual rates of change to estimate temporal changes in physical functionality and coral cover. Moreover, a functional diversity framework was used to explore changes in coral composition and the traits of those assemblages. Between 2005 and 2018, physical functionality increased at a markedly lower rate compared to that of coral cover. The disparity between recovery rates depended on the identity of the species that increased (mainly non‐framework and foliose‐digitate corals). No changes in species dominance or functional trait composition were observed, whereas non‐framework building corals consistently dominated most reefs. Although the observed recovery of coral cover and functional potential may provide some ecological benefits, the long‐term effects on reef frameworks remain unclear, as changes in the cover of key reef‐building species were not observed. Our findings are likely to be representative of many reefs across the wider Caribbean basin, as declines in coral cover and rapid increases in the relative abundance of weedy corals have been reported regionally. A coral identity approach to assess species turnover is needed to understand and quantify changes in the functionality of coral reefs.
Pocillopora corals, the dominant reef-builders in the Eastern Tropical Pacific, exhibit a high level of phenotypic plasticity, making the interpretation of morphological variation and the identification of species challenging. To test the hypothesis that different coral morphospecies represent phenotypes that develop in different flow conditions, we compared branch characters in three Pocillopora morphospecies (P. damicornis, P. verrucosa, and P. meandrina) from two communities in the Gulf of California exposed to contrasting flow conditions. Morphological variation and branch modularity (i.e., the tendency of different sets of branch traits to vary in a coordinated way) were assessed in colonies classified as Pocillopora type 1 according to two mitochondrial regions. Our results can be summarized as follows. (1) Pocillopora type 1 morphospecies corresponded to a pattern of morphological variation in the Gulf of California. Overall, P. damicornis had the thinnest branches and its colonies the highest branch density, followed by P. verrucosa, and then by P. meandrina, which had the thickest branches and its colonies the lowest branch density. (2) The differentiation among morphospecies was promoted by different levels of modularity of traits. P. verrucosa had the highest coordination of traits, followed by P. damicornis, and P. meandrina. (3) The variation and modularity of branch traits were related to water flow condition. Morphology under the high-flow condition was more similar among morphospecies than under the low-flow condition and seemed to be related to mechanisms for coping with these conditions. Our results provide the first evidence that in scleractinian corals different levels of modularity can be promoted by different environmental conditions.
Desde la década de 1960, se han realizado estudios para comprender el proceso de calcificación que llevan a cabo los corales hermatípicos y conocer los factores que limitan su crecimiento. Wells (1963) determinó que los parámetros de crecimiento coralino guardan una relación directa con las variaciones estacionales en las condiciones ambientales. Calcification of the main reef-building coral species on the Pacific coast of southern Mexico Calcificación de las principales especies de corales constructoras de arrecifes en la costa del Pacífico del sur de México
Porites panamensis is a hermatypic coral present in the eastern Pacific Ocean. Skeletal growth parameters have been reported, but studies of the relationship between annual calcification rates and environmental controls are scarce. In this study, we investigated three aspects of the annual calcification rates of P. panamensis: growth parameters among three P. panamensis populations; the sea surface temperature as a calcification rate control spanning a latitudinal gradient; and calcium carbonate production among three sites. Growth parameters varied among the sites due to the colony growth form. Massive colonies in the north showed a higher calcification rate than encrusting colonies in the south (mean: 1.22-0.49 g CaCO 3 Á cm À2 Á yr À1 ), where variations in calcification rates were related to growth rate (0.91-0.38 cm Á yr À1 ) rather than to skeletal density differences (overall mean AE SD, 1.31 AE 0.04 g CaCO 3 Á cm À3 ). Our results showed a positive linear relationship between annual calcification rates and sea surface temperatures within these P. panamensis populations. Differences were related to distinct oceanographic environments (within and at the entrance of the Gulf of California) with different sea surface temperature regimes and other chemical properties. Different populations calcified under different environmental conditions. Calcium carbonate production was dependent upon the calcification rate and coral cover and so carbonate production was higher in the north (coral cover 12%) than in the south (coral cover 3.5). Thus, the studied sites showed low calcium carbonate production (0.25-0.43 kg CaCO 3 Á m À2 Á yr À1 ). Our results showed reduced calcification rates, regional temperature regime control over calcification rates, different growth forms, low coral cover and low calcium carbonate production rates in P. panamensis.Marine Ecology (2014) 1-12 ª
In the emerald coral Porites panamensis, the rates of elongation and calcification of colonies are higher in males than in females, probably because of the higher energetic demands of the latter in order to cope with the development of the large planulae produced throughout the year. This differing energetic demand could also be reflected in the sexual dimorphism of the calyces; hence, to test this hypothesis, 11 morphological traits of the corallite were assessed from 63 colonies that were collected in the southern Gulf of California, Mexico. Three traits showed statistical differences between sexes, enabling accurate distinction of males from females. Our results confirm for the first time the existence of external sexual dimorphism in a reef-building coral, opening the possibility that sex-related morphological differences may occur generally in gonochoric scleractinians. These findings can be very useful for the correct classification and characterization of recent and fossil records, helping to improve the historical and evolutive understanding of reef-building corals facing threats under environmental changes.
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