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Nature study identifies need for new data to map the effect of water security investments on freshwater biodiversity

October 13, 2010

Writing last month in Nature, Charles Vörösmarty and colleagues provide the first global synthesis of threats to human water security and biodiversity services provided by freshwater ecosystems.  The study shows that human water security and freshwater biodiversity share many threats. However, vastly more data and investment is available for improving human water security than for freshwater biodiversity conservation. Importantly, the fact that many water security interventions impact negatively on freshwater biodiversity highlights the challenges in balancing ecosystem management to address both human livelihood improvement and biodiversity conservation.

The study collated data on 23 stressors on freshwater systems under four themes – catchment disturbance, pollution, water resource development and biotic factors – to suggest that over 80% (4.8 billion people) of the world’s population is exposed to high levels of water security threat.


Global geography of incident threat to river biodiversity. Blues reflect lower threat, reds reflect higher threat. From (13/10/10)


The highest threats (yellows, oranges and reds) to both water security and biodiversity were found where water resource development (e.g. dams and flood defences) and pollution levels were highest – in Europe, the USA, China and India.  As there are many (and often local) factors that influence threat calculation, Vörösmarty and colleagues argue for integrated strategies to address ecosystem rehabilitation.


Global geography of threat to human water security when adjusted to include investment into water technologies. Blues reflect lower threat; reds reflect higher threat From (13/10/10)


Wealthy nations are in a better position to improve their water security through technological investments (e.g. reservoirs, sanitation plants), thus widening the gap with poorer countries.  Vörösmarty and colleagues suggest that such investments into improving human water security may have direct negative impacts on biodiversity (e.g. dams impeding migratory fishes). Unfortunately, due to the lack of available data the authors were unable to map the effects of this investment on biodiversity.

As the environmental impacts of climate change and population growth increase in the future, the challenge of implementing such integrated management strategies is likely to become increasingly important.  However, without adequate data on the distribution, status and trends of global freshwater biodiversity, how can successful integrated management strategies be designed?  As Vörösmarty and colleagues suggest, policymakers and water managers require high-resolution biodiversity data at scales relevant to their decision-making.

The BioFresh project aims to build a freshwater biodiversity information platform to bring together, and make publicly available, the vast amount of information on freshwater biodiversity currently scattered among a wide range of databases.  However, this study demonstrates that there is a need for futher work in quantifying and communicating the threats faced by global freshwater biodiversity.

The fundamental question remains: how to manage global ecosystems in a manner that balances the needs of both humans and nature?  As ever, we’d welcome your comments.


Vörösmarty, CJ, McIntyre, PB, Gessner, MO, Dudgeon, D, Prusevich, A, Green, P, Glidden, S, Bunn, SE, Sullivan, CA, Reidy Liermann, C & Davies, PM (2010), ‘Global threats to human water security and river biodiversity’, Nature, vol. 467, no, 7315, pp. 555-561.  Link

Links to further information:

The River Threat partnership

The BioFresh project homepage

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