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Coral reefs are the most diverse habitat per unit area in the world's oceans, supporting an estimated 1–3 million species in only 0.2% of its area. These ecosystems have suffered severe declines since the 1970s, largely as a result of climate change, ocean acidification, pollution, disease, and overfishing. Porites astreoides is a shallow species that is able to thrive in a variety of environmental conditions and has been a clear 'winner' on Atlantic reefs in the last decades. This, coupled with its ease of identification and wide distribution, has caused P. astreoides to become a focal species in many scientific studies. Given the current and increasing significance of P. astreoides, this review sought to (i) identify the key life history traits that allowed this species to thrive under stressful conditions; (ii) compile aspects of its biology and ecology to understand its future contribution to Atlantic reefs, and (iii) identify knowledge gaps. To date, no comprehensive overview of the literature exists for P. astreoides. All articles available on Google Scholar up to the time of submission containing the terms 'Mustard Hill Coral', 'Porites astreoides', or 'P. astreoides' were examined for potential inclusion in this review. Papers were assessed based on whether they captured the most influential or widespread theories, represented an important trend in the research, or contained novel findings relevant to the understanding of this species. This review provides a scholarly resource and wide-ranging synthesis of P. astreoides on Atlantic reefs of today and the future. [ABSTRACT FROM AUTHOR]

Coral growth is an important metric of coral health and underpins reef-scale functional attributes such as structural complexity and calcium carbonate production. There persists, however, a paucity of growth data for most reef-building regions, especially for coral species whose skeletal architecture prevents the use of traditional methods such as coring and Alizarin staining. We used structure-from-motion photogrammetry to quantify a range of colony-scale growth metrics for six coral species in the Mexican Caribbean and present a newly developed workflow to measure colony volume change over time. Our results provide the first growth metrics for two species that are now major space occupiers on Caribbean reefs, Agaricia agaricites and Agaricia tenuifolia. We also document higher linear extension, volume increase and calcification rates within back reef compared to fore reef environments for four other common species: Orbicella faveolata, Porites astreoides, Siderastrea siderea and Pseudodiploria strigosa. Linear extension rates in our study were lower than those obtained via computed tomography (CT) scans of coral cores from the same sites, as the photogrammetry method averages growth in all dimensions, while the CT method depicts growth only along the main growth axis (upwards). The comparison of direct volume change versus potential volume increase calculated from linear extension emphasizes the importance of assessing whole colony growth to improve calcification estimates. The method presented here provides an approach that can generate accurate calcification estimates alongside a range of other whole-colony growth metrics in a non-invasive way. [ABSTRACT FROM AUTHOR]

Despite coral community collapse, the mustard hill coral (Porites astreoides) is a species currently experiencing success throughout the Caribbean. The inshore reefs of Grenada were selected to study the influence of benthic factors on the abundance, size, and coverage of P. astreoides colonies. Surveys of reef communities along established 30 m transects were conducted at eight sites in 2014 and 2017 using a 0.5 m² quadrat. Coral Point Count was used to annotate the images, estimating the coverage of scleractinian corals, sponges, algae, and benthic substrates. Coverage, size, and abundance of P. astreoides colonies were quantified using the area measurement tool in ImageJ standardized against the quadrats. There were significant differences in benthic community assemblages between islands, selected sites, and between years. From 2014 to 2017 there was a significant decrease in the mean abundance of P. astreoides colonies and significant increases in mean colony size and coverage. The presence of P. astreoides colonies was significantly correlated with: rubble (−), sand (−); pavement (+); macroalgae (−); coralline algae (+); sponges (varying response); gorgonians (−); massive corals (+); and branching corals (−). P. astreoides follows similar recruitment patterns as other scleractinian corals. Observed changes in P. astreoides populations appear to indicate a recovery event following a disturbance, potentially tropical storm Chantal in 2013. [ABSTRACT FROM AUTHOR]