(pdf) Abstract:  Despite global coral reef degradation, Porites astreoides has become increasingly dominant on Florida and Caribbean reefs and is often considered climate-resilient. However, whether its apparent success reflects an increase in absolute abundance or simply a rise in relative abundance remains unclear, as does its ability to persist under continued climate stress. Using Coral Reef Evaluation and Monitoring (CREMP) data from 40 sites across the Florida Keys Reef Tract from 2011–2024, we evaluated temporal changes in colony abundance, percent cover, time-specific population growth, and colony size-class distributions of P. astreoides. We compared these responses with commonly observed species, Siderastrea siderea and Montastraea cavernosa. We then implemented a hurdle model to assess the projected response of coral cover, colony abundance, and probability of extinction related to Degree Heating Weeks (DHW) and water depth. For P. astreoides, increasing DHW was associated with decreased population growth and percent cover, demonstrating stronger negative responses than both comparison species. Projected population growth based on colony abundance fell below replacement at approximately 7.5 DHW. The relationship with DHW was largely driven by the 2023 mass-bleaching event. However, the negative rela-tionship found between DHW, as well as the large (47.3%) decline in percent cover following the heat wave, suggests that tissue loss and reductions in colony size may precede declines in colony abundance. P. astreoides abundance and percent cover responded negatively to increased water depth, although for percent cover, deeper reefs may partially buffer the negative effect of thermal stress. Following the 2023 marine heatwave, medium and large P. astreoides colonies declined substantially while small colonies made up an increasing proportion of the population. Collectively, these findings indicate that the continued presence and increasing relative dominance of P. astreoides should not be interpreted as evidence of climate resilience. Instead, the species appears to be undergoing demographic decline and size structure diminution, which may be masked when either colony abundance or percent cover is considered alone. Evaluating population growth, percent cover, and colony size structure together provides a more complete assessment of coral resilience and the capacity of future reefs to maintain structural complexity and ecosystem function.