Abstract
It is incontrovertible that many coral reefs are in various stages of decline and may be unable to withstand the effects of global climate change, jeopardizing vital ecosystem goods and services to hundreds of millions of people around the world. An estimated 50% of the world's corals have already been lost, and those remaining may be lost by 2030 under the “business as usual” CO2 emissions scenario. However, the foundation of these predictions is a surprisingly sparse dataset, wherein ~0.01–0.1% of the world's reef area has been quantitatively surveyed. Further, the available data comprise observations at the 1–10 m scale, which are not evenly spaced across reefs, but often clustered in areas representing focused survey effort. This impedes modeling and predicting the impact of a changing environment at the ecosystem scale. Here we highlight deficiencies in our current understanding of the relationship between coral reefs and their environments. Specifically, we conduct a meta-analysis using estimates of coral cover from a variety of local surveys, quantitatively relating reef condition to a suite of biogeophysical forcing parameters. We find that readily available public data for coral cover exhibit unexpected trends (e.g., a positive correlation between coral cover and multi-year cumulative thermal stress), contrary to prevailing scientific expectations. We illustrate a significant gap in our current understanding, and thereby prediction, of coral reefs at the ecosystem scale that can only be remedied with uniform, high-density data across vast coral reef regions, such as that from remote sensing.
Highlights
Coral reefs are distributed throughout the world’s tropical oceans, directly occupying an estimated area of 250,000–600,000 km2 [Figure 1; (Smith, 1978; Kleypas, 1997; Spalding and Grenfell, 1997)]
Observed trends in coral cover were as expected with respect to 10-year maximum BAA (Figure 3B, see number at top-right of panel for Spearman rank correlation coefficient), 10-year BAA trend (Figure 3C), number of significant wave height (SWH) events (Figure 3E), number of coral species (Figure 3G), and local marine pollution threat (Figure 3J)
We found a negative trend of coral cover in association with light availability (Figure 3F)
Summary
Coral reefs are distributed throughout the world’s tropical oceans, directly occupying an estimated area of 250,000–600,000 km2 [Figure 1; (Smith, 1978; Kleypas, 1997; Spalding and Grenfell, 1997)]. These values correspond to ∼0.05–0.15% of the global ocean area, respectively, and about 5–15% of the shallow sea areas within 0–30 m depth. Coral reefs have ecological and economic importance that is disproportionately large relative to their areal extent. While the accuracy of this dollar amount is debatable, it is certain that coral reefs are important to the cultural and economic lives of hundreds of millions of people around the world, providing food for innumerable small subsistence economies, shoreline protection, superlative recreational resources, and biological storehouses for the biotechnology industry (Moberg and Folke, 1999).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
