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Abstract Understanding how foundation species recover from disturbances is key for predicting the future of ecosystems in the Anthropocene. Coral reefs are dynamic ecosystems that can undergo rapid declines in coral abundance following disturbances. Understanding why some reefs recover quickly from these disturbances whereas others recover slowly (or not at all) gives insight into the drivers of community resilience. From 2006 to 2010 coral reefs on the fore reef of Moorea, French Polynesia, experienced severe disturbances that reduced coral cover from ~46% in 2005 to <1% in 2010. Following these disturbances, coral cover increased from 2010 to 2018. Although there was a rapid and widespread recovery of corals, reefs at 17 m depth recovered more slowly than reefs at 10 m depth. We investigated the drivers of different rates of coral recovery between depths from 2010 to 2018 using a combination of time‐series data on coral recruitment, density, growth, and mortality in addition to field experiments testing for the effects of predation. Propagule abundance did not influence recovery, as the density of coral recruits (spat <6 months old) did not differ between depths. However, mortality of juvenile corals (≤5 cm diameter) was higher at 17 m, leading to densities of juvenile corals 3.5 times higher at 10 m than at 17 m depth. Yet, there were no differences in the growth of corals between depths. These results point to an early life stage bottleneck after settlement, resulting in greater mortality at 17 m than at 10 m as the likely driver of differential coral recovery between depths. We used experiments and time‐series data to test mechanisms that could drive different rates of juvenile coral mortality across depths, including differences in predation, competition, and the availability of suitable substratum. The results of these experiments suggested that increased coral mortality at 17 m may have been influenced by higher intensity of fish predation, and higher mortality of corals attached to unfavorable substratum. In contrast, the abundance of macroalgae, a coral competitor, did not explain differences in coral survival. Our work suggests that top‐down processes and substratum quality can create bottlenecks in corals that can drive rates of coral recovery after disturbance.
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MCR LTER: Coral Reef: Coral mortality in the lagoon of Moorea in 2019
The data included in this data package were collected in the lagoon of Moorea, French Polynesia. Data on coral mortality were collected in July 2019. Data on nitrogen content (%N) in the long-lived brown macroalga Turbinaria ornata were collected during six sampling campaigns between January 2016 and May 2021 to characterize nitrogen availability at each site. Data on seawater temperatures at six LTER sites in the back reef were collected from 2005-2019, but temperature loggers at two sites (LTER 1 and LTER 6) only recorded partial ocean temperature records during the heatwave from 2018-2019. We used our entire time series (spanning from 2005 to 2018) of temperature across our four long-term sites for which we have data in 2019 to predict ocean temperature data for LTER 1 and LTER 6 in 2019. These data were used for analyses in the manuscript entitled "Effects of nitrogen enrichment on coral mortality depend on the intensity of heat stress".
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- Award ID(s):
- 2205892
- PAR ID:
- 10670909
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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