Understanding how coral reefs respond to natural disturbances is fundamental to assess their resistance and resilience, particularly in a context of climate change. Therefore, and given the escalating frequency and intensity of bleaching events, it is essential to evaluate responses of communities in space and time to disentangle the mechanisms underlying ecological changes. Here, I analyzed a dataset comprising 59 reefs, resulting from 6 years (2014-2016) of a coral reef benthic monitoring program in the Saudi Arabian Red Sea. It encompasses the 2015/2016 mass bleaching event and spans three different geographic regions: north (Duba and Al Wajh), central (Jeddah and Thuwal), and south (Al Lith, Farasan Islands and Farasan Banks). The results indicate significant differences between regions and through time. Coral assemblages from the southern region were the most affected by the 2015 bleaching event, where in some reefs, hard and soft corals cover dropped to <2% in 2017. Important changes in community structure were observed through time in the three regions, with a shift to a macroalgae, turf algae and CCA dominance. Different environmental drivers (salinity, sea surface temperature, fishing index, distance to shore, and photosynthetically active radiation) were analyzed, and highlighted a regionally-based response of the communities to these potential drivers of change. Overall, the examined Red Sea benthic communities presented dynamic patterns in composition. Distance decay plots based on presence/absence showed a general increase in similarity throughout multiple spatial scales in 2019, when compared to previous years. This finding suggests a loss in biodiversity due to thermal anomalies and bleaching events, evidenced by a homogenization (i.e., increase similarity) in the composition of the benthic communities. I document here a patterns of dominance of a few benthic groups with time and a decrease in branching corals. This study provides baseline information about changes in coral reef benthic community structure and identifies environmental factors with a higher impact on a regional scale. This information can be used to guide conservation efforts in these highly biodiverse ecosystems.The resulting datasets can be valuable for anticipating responses of coral communities under future climate scenarios.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/668997 |
| Date | 04 1900 |
| Creators | Gonzalez-Martinez, Karla Paola |
| Contributors | Berumen, Michael L., Biological and Environmental Sciences and Engineering (BESE) Division, Carvalho, Susana, Benzoni, Francesca |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | 2022-04-28, At the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis will become available to the public after the expiration of the embargo on 2022-04-28. |
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