News Release

Reef diversity no insurance against human threats

Peer-Reviewed Publication

PLOS

In a large collaborative analysis publishing tomorrow in the online, open access journal PLoS Biology, 55 scientists from 49 nations document that the capability of reef fish systems to produce biomass and deliver goods and services to humanity, is functionally linked to the number of species; functioning increases as biodiversity increases. However, mounting pressures from growing human populations is tampering with this functioning of the reef fish communities, especially in the most diverse reefs. The extent of this distress was shown to be widespread and likely to worsen as some 75% of the world's coral reefs are near human settlements and because most countries with coral reefs are expected to double their human populations within the next 50 to 100 years.

A two year study was initiated to collect the necessary data to determine if biodiversity influences the functioning of reef fish systems, and if so, elucidate the role of humans in such a linkage. The team collected data on the identity of species, their abundances and body sizes in almost two thousand coral reef locations worldwide. These data were then used to calculate the standing biomass of reefs, which is one of the main services reef fishes provide to humanity through food supply but can also be used as a proxy for biomass production, which is among a metric of ecosystem functioning used in previous studies. The data on diversity and standing biomass were combined with demographic data on human populations and analyzed with sophisticated statistical approaches to determine the linkages between biodiversity, functioning and people.

The study demonstrated that biomass, and therefore ecosystem functioning, decreased with increasing human density although for the same number of people the loss of function was significantly larger in more diverse ecosystems. The stronger deleterious effect of humanity on more diverse reefs is possibly due to the selective local extinction of large fishes, which may have a disproportionate affect on function and whose ecological roles are less likely to be replaced by other species.. Unfortunately, the study documents that the deleterious effect of humanity is widespread and likely to worsen in the near future, as some 75% of world's coral reefs are near human settlements and because almost all countries with coral reefs are expected to double their populations within the next 50 to 100 years.

"Coral reefs are the most diverse ecosystem on the planet hosting thousands of species and generating goods and services through food, tourism and coastal protection to millions of people worldwide" says Enric Sala, a National Geographic fellow and coauthor of the study. "The future of coral reefs and the services they provide to a growing human population depend on how soon countries become seriously committed to regulating human threats" he adds.

Nevertheless, the study also reports that at least 25% of the world reefs remain distant from direct human effects. Those reefs are located on small and isolated areas where the habitat is too harsh for humans to live. Such isolated reefs might provide a potential source to replenish degraded reefs when solutions to the coral reef crisis can be determined.

"Human overpopulation is a very sensitive topic across endeavors from science to religion and politics" says Camilo Mora at Dalhousie University and lead researcher of the study.. "Unfortunately, we find again and again that our global population cannot be sustainably supported without the deterioration of the world's natural resources and its' backlash on human welfare. Thus, identifying socially and politically acceptable solutions to curb human population growth is at the core of finding ultimate solutions for the protection of biodiversity and the prevention of unnecessary hardship."

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Funding: The main funding was provided by the Sloan Foundation through the Census of Marine Life's Future of Marine Animal Populations and Natural Geography in Shore Areas projects. Additional funding and support were provided by the Royal Society; the Leverhulme Trust; Nakheel PJSC; the Gordon and Betty Moore Foundation; Galapagos National Park Service; Charles Darwin Foundation; Conservation International; Walton Family Foundation; the Australian Research Council; National Geographic; the Western Indian Ocean Marine Science Association; the German National Academic Foundation; the Coral Reef Conservation Program of the National Oceanic and Atmospheric Administration; The National Marine Fisheries Service Office of Habitat Conservation; the 21st Century Centers of Excellence Program of the Japan Society for the Promotion of Science; the French Institute for Biodiversity; the David and Lucile Packard Foundation; the Wildlife Conservation Society; the United States National Science Foundation's Long-term Ecological Research Program; The Conservation Leadership Programme; Australian Institute of Marine Sciences; the Australian Department of Environment, Water, Heritage and the Arts; The Marisla Foundation Environment Program; the World Wildlife Fund; The Ocean Conservancy; and the Natural Sciences and Engineering Council of Canada. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests statement: The authors declare that no competing interests exist.

Citation: Mora C, Aburto-Oropeza O, Ayala Bocos A, Ayotte PM, Banks S, et al. (2011) Global Human Footprint on the Linkage between Biodiversity and Ecosystem Functioning in Reef Fishes. PLoS Biol 9(4): e1000606. doi:10.1371/journal.pbio.1000606

PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.1000606

IMAGE: http://www.plos.org/press/plbi-09-04-Mora.jpg

o Caption: Coral reefs worldwide are slowly being degraded due to an increasing human population and resulting threats from coastal development, fishing, pollution, and agricultural land use. Without immediate international attention, coral reefs may be soon beyond repair. Photos by Humberto Bahena and Henry Wolcott, Mark Defeo, Tyler Smith, Steve Spring, Stephen McGowan from Marine Photobank. Photos for articles covering this story are available at: www.fmap.dal.ca/pressmaterial.php

CONTACT:
Camilo Mora, Ph.D.
Dalhousie University, Halifax, NS
Canada
Email: cmora@dal.ca
Phone: 57 (313) 776 2282 (Colombia)

Enquires for specific countries or regions can be made to specific authors, whose countries and regions are outlined at: www.fmap.dal.ca/pressmaterial.php


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