IsAcropora palmatarecovering? a case study in Los Roques National Park, Venezuela

Abstract

Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout Los Roques archipelago in Venezuela. The aim was to produce a baseline study for this species which combined population genetics with demographic data. The results highlighted that A. palmata had the potential to recover in at least 6 out of 10 sites surveyed. Recovery potential was assumed to be high at sites with a relatively high abundance of the coral, low disease prevalence, high genetic diversity, and high rates of sexual reproduction. However, as noted, Zubillaga et al. (2008) realized recovery was still strongly dependent on local and regional stressors. In 2014 (this study), the status of A. palmata was re-evaluated at Los Roques. We increased the number of sites from 10 in the original baseline study to 106. This allowed us to assess the population status throughout the entirety of the MPA. Furthermore, we also identified local threats that may have hindered population recovery. Here, we show that A. palmata now has a relatively restricted distribution throughout the park, only occurring in 15% of the sites surveyed. Large stands of old dead colonies were common throughout the archipelago; a result which demonstrates that this species has lost almost 50% of its original distribution over the past decades. The majority of corals recorded were large adults (∼2 m height), suggesting that these older colonies might be less susceptible or more resilient to local and global threats. However, 45% of these surviving colonies showed evidence of partial mortality and degradation of living tissues. Interestingly, the greatest increase in partial mortality occurred at sites with the lowest levels of protection (; df = 4, p < 0.05). This may suggest there is a positive role of small scale marine management in assisting reef recovery. We also recorded a significant reduction (; df = 8; p < 0.05) in the density of A. palmata in sites that had previously been categorized as having a high potential for recovery. One explanation for this continued decline may be due to the fact that over the past 10 years, two massive bleaching events have occurred throughout the Caribbean with records showing that Los Roques has experienced unprecedented declines in overall coral cover. We therefore conclude that although local protection could promote recovery, the impacts from global threats such as ocean warming may hamper the recovery of this threatened species.

Los Roques and Las Aves Archipelagos, Venezuela: A Marine Ecological and Conservation Reconnaissance of Two Little-Known Southeastern Caribbean Oceanic Archipelagos

“…The area has also been found to be vulnerable to changes in regional oceanographic processes, in particular changes in wind-induced upwelling (Villamizar & Cervigón 2017). Cróquer et al (2016) present evidence that the coral Acropora palmata has lost almost 50% of its original distribution in Los Roques in recent decades. While this level of loss is much lower than most other areas of the Caribbean, it does highlight the continued vulnerability of this species to global threats such as ocean warming.…”

“…While this level of loss is much lower than most other areas of the Caribbean, it does highlight the continued vulnerability of this species to global threats such as ocean warming. Notwithstanding important outbreaks of white band disease among the acroporid corals of Los Roques (Cróquer et al 2005), the park protects one of the few areas of the Caribbean that has retained relatively high densities of Acropora reefs (Zubillaga et al 2005, Cróquer et al 2016) since the mid-1980 when the species declined precipitously throughout the Caribbean. Zubillaga et al (2008) found important signs of population recovery for the species three decades after the Caribbean-wide mass mortality took place.…”

Benthic community structure on coral reefs exposed to intensive recreational snorkeling

“…palmata and staghorn corals A . cervicornis historically dominated reefs throughout the Caribbean Sea [ 71 ], but have declined drastically due to the compounding influences of anthropogenic and natural disturbances [ 72 , 73 ], including hurricanes Emily and Wilma which both hit the Yucatan Peninsula in 2005 [ 48 , 49 ]. The relationships examined here between the remaining acroporid percent cover and snorkeling level disappeared when the outer bay (reef crest) sites were removed, indicating their percent cover may be driven more by outer-inner bay physical gradients than snorkeler pressure.…”

Status of the pillar coralDendrogyra cylindrusin Los Roques National Park, Southern Caribbean

“…Habitat characterization at each site was assessed qualitatively according to the habitat type, habitat condition and geomorphological unit. Habitat type was based on the main substrate and dominance of benthic species following Croquer et al (2016) and Bernal-Sotelo et al (2019). This rapid characterization is suitable for rough descriptions of the coral benthic communities at spatial scales above 50 m (Hill and Wilkinson, 2004) as in this study.…”