Abstract
This study used annual high-resolution photomosaic imagery and spatially aligned polygon data from Cheeca Rocks transect 1 (2012–2014) to examine colonylevel changes in spatial structure, bleaching responses, and short-term mortality for four coral taxa: Orbicella annularis (OANN, formerly MANN), Porites astreoides (PAST), Porites porites (PPOR), and Siderastrea siderea (SSID). By combining TagLab annotations, nearest-neighbor distance calculations in ArcGIS Pro, and bleaching and mortality metrics generated in R Studio, this work documented community-level changes at the scale of individual colonies.
Results indicated that 2014 was the most intense bleaching year of the study period. Bleaching rates for OANN and PPOR reached nearly 100% in September 2014, while PAST was around 20%, and SSID remained at 0% for all surveys. Mortality patterns followed these trends: OANN and PAST declined throughout the study period, with PAST showing the highest loss (−25%) between 2013 and 2014 (August). PPOR experienced a moderate decline (−11.4%) in the same interval, whereas SSID had no recorded mortality. For spatial structure, only OANN presented statistically significant differences of mean nearest-neighbor distance, while the remaining species evidenced relatively stable spacing patterns from 2012 to 2014.
Overall, results suggest that the 2014 regional thermal anomaly was the main driver of bleaching and population declines at Cheeca Rocks, while species-specific thermal tolerance was a key factor in setting community-level responses. Incorporating the 2015–2018 aligned photomosaic layers in future work will allow a more complete assessment of long-term recovery, spatial re-organization, and the effects of repeated disturbances under continued climate stress.