Biodiversity enhances reef fish biomass and resistance to climate change
Edited by James A. Estes, University of California, Santa Cruz, CA, and approved April 13, 2016 (received for review December 11, 2015)
Significance
Marine fisheries provide a major global source of protein, feeding billions of people, but they face destabilization in many regions from overexploitation and climate change. Using the most comprehensive dataset of fish diversity and abundance, encompassing over 4,500 surveys from nearshore habitats around the world, we show that biodiversity is among the strongest predictors of reef fish community biomass, comparable in importance to global temperature gradients and human impacts. Importantly, diverse fish communities were more resistant to rising and variable temperature, suggesting that high biodiversity also buffers against changing climate. Maintaining taxonomically and functionally diverse fish communities can thus stabilize fisheries’ yields in a changing ocean.
Abstract
Fishes are the most diverse group of vertebrates, play key functional roles in aquatic ecosystems, and provide protein for a billion people, especially in the developing world. Those functions are compromised by mounting pressures on marine biodiversity and ecosystems. Because of its economic and food value, fish biomass production provides an unusually direct link from biodiversity to critical ecosystem services. We used the Reef Life Survey’s global database of 4,556 standardized fish surveys to test the importance of biodiversity to fish production relative to 25 environmental drivers. Temperature, biodiversity, and human influence together explained 47% of the global variation in reef fish biomass among sites. Fish species richness and functional diversity were among the strongest predictors of fish biomass, particularly for the large-bodied species and carnivores preferred by fishers, and these biodiversity effects were robust to potentially confounding influences of sample abundance, scale, and environmental correlations. Warmer temperatures increased biomass directly, presumably by raising metabolism, and indirectly by increasing diversity, whereas temperature variability reduced biomass. Importantly, diversity and climate interact, with biomass of diverse communities less affected by rising and variable temperatures than species-poor communities. Biodiversity thus buffers global fish biomass from climate change, and conservation of marine biodiversity can stabilize fish production in a changing ocean.
Acknowledgments
We thank the many Reef Life Survey divers, researchers, and managers who participated in data collection and provide ongoing expertise and commitment to the program; University of Tasmania staff responsible for Reef Life Survey data management, Antonia Cooper and Just Berkhout; Stuart Kininmonth for providing the population index and mapping; and Doug Rasher and an anonymous reviewer for comments that improved the manuscript. Additional support was provided by the former Commonwealth Environment Research Facilities Program, the Ian Potter Foundation, the Australian Research Council, the Institute for Marine and Antarctic Studies, the Marine Biodiversity Hub, a collaborative partnership supported through the Australian Government’s National Environmental Science Programme, and the Smithsonian Institution. This is contribution 9 from the Smithsonian’s Tennenbaum Marine Observatories Network.
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Cover image: Pictured is a group of livestock feeding on plant matter, which ruminant animals partly digest in the rumen with the aid of microorganisms that ferment the plant matter into various compounds, including the greenhouse gas methane. Evert Duin et al. found that the small molecule 3-nitrooxypropanol inactivates an enzyme involved in the formation of methane during rumen fermentation, thus limiting the growth of methanogenic archaea in the rumen. See the article by Duin et al. on pages 6172–6177. Image courtesy of Fotolia/thiededesign.
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Published online: May 16, 2016
Published in issue: May 31, 2016
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Acknowledgments
We thank the many Reef Life Survey divers, researchers, and managers who participated in data collection and provide ongoing expertise and commitment to the program; University of Tasmania staff responsible for Reef Life Survey data management, Antonia Cooper and Just Berkhout; Stuart Kininmonth for providing the population index and mapping; and Doug Rasher and an anonymous reviewer for comments that improved the manuscript. Additional support was provided by the former Commonwealth Environment Research Facilities Program, the Ian Potter Foundation, the Australian Research Council, the Institute for Marine and Antarctic Studies, the Marine Biodiversity Hub, a collaborative partnership supported through the Australian Government’s National Environmental Science Programme, and the Smithsonian Institution. This is contribution 9 from the Smithsonian’s Tennenbaum Marine Observatories Network.
Notes
This article is a PNAS Direct Submission.
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The authors declare no conflict of interest.
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