Study sheds new light on how species extinction affects complex ecosystems

March 03, 2017

Research by the University of Southampton has found that methods used to predict the effect of species extinction on ecosystems could be producing inaccurate results. This is because current thinking assumes that when a species vanishes, its role within an environment is lost too.

However, scientists working on a new study have found that when a species, (for example a group of sea creatures), is wiped out by a catastrophic event, other species can change their behaviour to compensate, exploiting the vacant role left behind. This leads to positive or negative effects on ecosystems, and in turn, either better or worse outcomes than current estimates would suggest.

At present, predictions assume that any contribution is completely lost at the point of extinction -leading to a decline in ecosystem performance.

The findings are published in the journal Scientific Reports. Lead author Matthias Schmidt Thomsen, of Ocean and Earth Science at the University of Southampton, says: "We have known for some time that a reduction in biodiversity has negative ecological consequences, but predictions of what happens to an ecosystem have not accounted for the occurrence of compensatory responses."

He added: "Our study provides evidence that the response of surviving species to novel circumstances can, at least partially, offset, or indeed exacerbate, changes in an ecosystem that are associated with species removal."

The researchers based their findings on the interaction of species in a community of invertebrates (such as clams, shrimps and worms) obtained from marine seabed samples collected in Galway Bay, Ireland. Bottom dwelling marine organisms are particularly vulnerable to extinction because they are often unable to avoid disturbance. These organisms are important because they churn up sediments from the bottom of the ocean, a process known as 'bioturbation', playing a vital role in returning nutrients to surrounding water as food for other creatures.

Using mathematical simulations, the team were able to explore what happens to the bioturbation process as species are removed from the system under different extinction scenarios. The simulations also accounted for the nuances of how other creatures would react as circumstances change. The direction and strength of response depends on the type of compensation and the extinction scenario.

Co-author, Dr Clement Garcia, an ecologist from the Centre for Environment, Fisheries and Aquaculture Science in Lowestoft said "There have been concerns over the gradual erosion of our natural habitat for some time. These findings will help resolve some of the detail that has previously been unavailable, allowing us to better identify both vulnerabilities and opportunities that coincide with environmental change and human endeavour."

The team's findings have important implications for the conservation of biological resources and habitat, and will support the refinement of models that are used to predict the consequences of human activity and environmental change.
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Notes to editors

1) A copy of the paper 'Consequences of biodiversity loss diverge from expectation due to compensatory responses' by Matthias S. Thomsen, Martin Solan, Jasmin A. Godbold, Clement Garcia, Stefan G. Bolam and Ruth Parker, Scientific Reports DOI: 10.1038/srep43695 is available from Media relations on request.

The paper will be available via open access at: http://www.nature.com/articles/srep43695

2) Co-authors can provide interviews in Danish, French or German by arrangement with Media Relations.

3) The work was a collaboration across two University academic units: Ocean and Earth Science (lead author Matthias S. Thomsen and Professor Martin Solan) and Biological Sciences (Dr. Jasmin A. Godbold) and; the Centre for Environment Fisheries and Aquaculture Science (Drs. Clement Garcia, Stefan G. Bolam and Ruth Parker). The study was jointly funded by the Natural Environment Research Council (NERC) and the Centre for Environment Fisheries and Aquaculture Science (CEFAS) in Lowestoft. The views expressed are those of the authors and do not necessarily represent those of NERC or CEFAS.

4) Ocean and Earth Science at the University of Southampton has a well-established reputation for outstanding research and teaching. Our unique waterfront campus at the National Oceanography Centre Southampton (NOCS) attracts prominent researchers and educators from around the world, who join us to work within the areas of geochemistry, geology and geophysics, marine biogeochemistry, marine biology and ecology, palaeoceanography and palaeoclimate and physical oceanography. Following publication of the national Research Excellence Framework 2014 (REF2014), OES was ranked second in the UK, for proportion of research recognised as world-leading (4*) in the Earth Systems and Environmental Sciences Unit of Assessment. http://www.southampton.ac.uk/oes/index.page

5) The University of Southampton is a leading UK teaching and research institution with a global reputation for leading-edge research and scholarship across a wide range of subjects in engineering, science, social sciences, health and humanities.

With over 24,000 students, 6500 staff, and an annual turnover in excess of £550m, the University of Southampton is acknowledged as one of the country's top institutions for engineering, computer science and medicine. We combine academic excellence with an innovative and entrepreneurial approach to research, supporting a culture that engages and challenges students and staff in their pursuit of learning.

The University is also home to a number of world-leading research centres including the Institute of Sound and Vibration Research, the Optoelectronics Research Centre, the Institute for Life Sciences, the Web Science Trust and Doctoral training Centre, the Centre for the Developmental Origins of Health and Disease, the Southampton Statistical Sciences Research Institute and is a partner of the National Oceanography Centre at the Southampton waterfront campus. http://www.southampton.ac.uk/

For further information contact:

Peter Franklin, Media Relations, University of Southampton, Tel: 023 8059 5457, Email: p.franklin@southampton.ac.uk

http://www.soton.ac.uk/mediacentre/

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University of Southampton

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