Is Acropora palmata really coming back? an analysis from Los Roques, Venezuela

Ten years ago, we studied the distribution and status of Acropora palmata at archipelago Los Roques because the actual status of this species at Los Roques was unclear in this archipelago after its regional collapse. In that opportunity we aimed to produce a baseline study for this species in Los Roques combining population genetics with demographic data. At that time, our results suggested that this species had the potential to come back at least in 6 out of 10 surveyed sites. This conclusion was based upon high abundance, low disease prevalence, high genetic diversity and a dominance of sexual reproduction in these populations. However, we recognized that the potential of recovery could be hindered depending on local and regional threats. In 2014, the status of this species was re-evaluated by increasing the number of sites from 12 to 106 and by identifying and targeting local and global threats that may affect population recovery. The results from this new survey showed that A. palmata had a restricted distribution being only present in 15% of the surveyed sites. Large stands of old dead colonies were common throughout the archipelago; which demonstrates that this species has lost almost 50% of its original distribution over the past decades. In most cases live colonies were large adults (̴ 2m height); however, partial mortality and degradation of living tissues were found in 45% of the colonies. Moreover 44.78% of them were located on degraded reefs. In the past 8 years, two massive bleaching events occurred in Los Roques, the last one was known to decrease coral cover to unprecedented levels in the the archipelago. These events might have produced significant mortality for this species for signs of recent mortality was also common across sites. In addition, a growing local tourism industry, which has become massive and the concomitant increase of pressure on ecosystems goods and services are both becoming a problem of serious concern. Our results suggest that increasing use conflicts within the MPA and global threats such as ocean warming could prevent the recovery of this endangered species in Los Roques.