Nav: Home

Even biodiverse coral reefs still vulnerable to climate change and invasive species

May 18, 2020

A new study reveals clear evidence highlighting the importance of fish biodiversity to the health of spectacular tropical coral reef ecosystems.

This is the case for reefs that are pristine and also those that have been affected by stresses, such as bleaching events caused by warming oceans.

However, the study's results show that even though strong relationships between diversity and a healthy ecosystem persist, human-driven pressures of warming oceans and invasive species still diminish ecosystems in various ways.

This highlights that protecting fish biodiversity is a key factor for improving the survival chances of coral reef ecosystems in the face of rapid environmental change. But the researchers caution that without removing human-driven stressors, protecting biodiversity alone might not be enough.

Dr Casey Benkwitt, of Lancaster Environment Centre and lead author of the study, said: "Our study, which is the first of its kind to look at relatively pristine coral, reveals the strong link between rich biodiversity and a thriving ecosystem. This relationship is still evident even when an ecosystem has been degraded and provides further clarity on just how crucial it is to maintain biodiversity to give tropical coral reefs a fighting chance to thrive in an uncertain future.

"However, the bad news is that the functioning of these fragile ecosystems is still vulnerable and was impaired in different ways by climate change and invasive species on nearby islands."

A team of researchers conducted surveys on coral reefs around ten islands in the remote Chagos Archipelago - the largest uninhabited and unfished coral reef area in the Indian Ocean.

Their surveys counted the number of different fish species on reefs as a measure of biodiversity. They also measured how well an ecosystem was functioning relative to fish biodiversity at different islands using two key indicators -the biomass of fish living on a reef, and a measure of productivity, which is the rate at which biomass is produced.

Dr Benkwitt, said: "We were surprised that the positive effects of biodiversity on ecosystem functions were so strong because such clear patterns are rare in ecological data. These results match previous studies on less pristine coral reefs, and in other terrestrial and marine systems. To see the same patterns in so many places suggests the positive relationship between diversity and ecosystem function may be one of the few general rules in ecology."

Importantly, the researchers also looked at coral reefs under pressure from multiple human-driven factors. This is the first time scientists have measured these kinds of effects outside of a lab.

The scientists had data from before and after a major heatwave in 2016 that caused bleaching and death of corals. This coral loss caused biodiversity to plummet by 17 per cent. Because of the strong relationship between biodiversity and ecosystem function, such losses in biodiversity caused by warming oceans will result in coral ecosystems that are not able to function as well.

Professor Nick Graham of Lancaster University and co-author of the study said: "The large negative effects of coral bleaching on biodiversity is worrisome as warming events are becoming more and more common. Because high diversity is key to ecosystem function, this means that preserving biodiversity may be increasingly important, but also increasingly challenging, in the future."

The scientists also studied coral reefs experiencing a reduction in nutrients caused by invasive rats on nearby islands. The rats, which arrived with people on boats decades ago, decimate wild bird populations, resulting in fewer droppings. These bird droppings act as fertiliser for the reefs when washed off into the sea, increasing fish growth rates and the amount of fish on a reef.

The researchers found that the coral reefs near islands with rats, and therefore with fewer seabird nutrients washing off to reefs, experienced lower levels of biomass. This shows that even when maintaining biodiversity, coral reef ecosystems are still vulnerable to human-caused stressors.

Dr Benkwitt said: "The bleaching event and loss of nutrients each reduced ecosystem functions in different ways. This means that managing each stressor will have complementary benefits for coral reefs. While biodiversity is clearly important to ecosystem function, biodiversity conservation may become more difficult and may not fully sustain ecosystems unless underlying stressors, such as climate change, are reduced."

The findings are outlined in the paper 'Biodiversity increases ecosystem functions despite multiple stressors on coral reefs', which has been published in the journal Nature Ecology and Evolution.
The paper's authors are: Cassandra Benkwitt and Nick Graham of Lancaster University and Shaun Wilson of the Department of Biodiversity Conservation and Attractions in Australia.

NOTE: This study is part of a collaborative and interdisciplinary programme of research established in 2016 by the Bertarelli Foundation in the British Indian Ocean Territory's 640,000km2 Marine Protected Area (MPA). The programme brings together more than 70 scientists from 18 institutions and seven countries to study the biology of complex marine ecosystems, apply science to improve the conservation and management of MPAs and improve 'ocean literacy' amongst the general public. Further information about the programme can be found at

DOI: 10.1038/s41559-020-1203-9

Lancaster University

Related Science Articles:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.
Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.
Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.
Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.
World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.
PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.
Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.
Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.
More Science News and Science Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at     You can read The Transition Integrity Project's report here.