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Abstract Climate plays a central role in coral-reef development, especially in marginal environments. The high-latitude reefs of southeast Florida are currently non-accreting, relict systems with low coral cover. This region also did not support the extensive Late Pleistocene reef development observed in many other locations around the world; however, there is evidence of significant reef building in southeast Florida during the Holocene. Using 146 radiometric ages from reefs extending ~ 120 km along Florida’s southeast coast, we test the hypothesis that the latitudinal extent of Holocene reef development in this region was modulated by climatic variability. We demonstrate that although sea-level changes impacted rates of reef accretion and allowed reefs to backstep inshore as new habitats were flooded, sea level was not the ultimate cause of reef demise. Instead, we conclude that climate was the primary driver of the expansion and contraction of Florida’s reefs during the Holocene. Reefs grew to 26.7° N in southeast Florida during the relatively warm, stable climate at the beginning of the Holocene Thermal Maximum (HTM) ~ 10,000 years ago, but subsequent cooling and increased frequency of winter cold fronts were associated with the equatorward contraction of reef building. By ~ 7800 years ago, actively accreting reefs only extended to 26.1° N. Reefs further contracted to 25.8° N after 5800 years ago, and by 3000 years ago reef development had terminated throughout southern Florida (24.5–26.7° N). Modern warming is unlikely to simply reverse this trend, however, because the climate of the Anthropocene will be fundamentally different from the HTM. By increasing the frequency and intensity of both warm and cold extreme-weather events, contemporary climate change will instead amplify conditions inimical to reef development in marginal reef environments such as southern Florida, making them more likely to continue to deteriorate than to resume accretion in the future.
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Estimating the potential for coral adaptation to global warming across the Indo‐West Pacific
Abstract The potential of reef‐building corals to adapt to increasing sea‐surface temperatures is often debated but has rarely been comprehensively modeled on a region‐wide scale. We used individual‐based simulations to model adaptation to warming in a coral metapopulation comprising 680 reefs and representing the whole of the Central Indo‐West Pacific. Encouragingly, some reefs—most notably Vietnam, Japan, Taiwan, New Caledonia and the southern half of the Great Barrier Reef—exhibited high capacity for adaptation and, in our model, maintained coral cover even under a rapid “business‐as‐usual” warming scenario throughout the modeled period (200 years). Higher resilience of these reefs was observed under all tested parameter settings except the models prohibiting selection and/or migration during warming. At the same time, the majority of reefs in the region tended to collapse within the first 100 years of warming. The adaptive potential (odds of maintaining high coral cover) of a given reef could be predicted based on two metrics: the reef's present‐day temperature, and the proportion of recruits immigrating from warmer locations. The latter metric explains the most variation in adaptive potential, and significantly correlates with actual coral cover changes observed throughout the region between the 1970s and the early 2000s. These findings will help prioritize coral conservation efforts and plan assisted gene flow interventions to boost the adaptive potential of specific coral populations.
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- Award ID(s):
- 1737312
- PAR ID:
- 10453659
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Global Change Biology
- Volume:
- 26
- Issue:
- 6
- ISSN:
- 1354-1013
- Page Range / eLocation ID:
- p. 3473-3481
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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