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Our top 15 posts of 2015

December 31, 2015

River Möll, Carinthia, Austria. Image: Rafaela Schinegger

As we reach the end of 2015 we wanted to say thanks to you, our readers.  It’s been a great year in which we’ve covered many fascinating studies, interviews and projects on freshwater science, policy and conservation.

Looking back over the year, here’s our top 15 posts of 2015.  Please feel free to tweet us @freshwaterblog with your favourite posts, and your suggestions for topics for the coming year.


1. Multiple Perspectives on Multiple Stress


A Mediterranean river: the Fango Valley in Corsica. Image: Ole Reidar Johansen (Flickr | Creative Commons)

“The January 2015 edition of the Science of the Total Environment journal features of selection of articles on the theme of “Towards a better understanding of the links between stressors, hazard assessment and ecosystem services under water scarcity.”  The issue features three articles by the supporters of this blog, the MARS, SOLUTIONS and GLOBAQUA projects, discussing three different perspectives on studying and managing multiple stressors – i.e. factors such as pollution and drought which may have negative effects on the ecosystem – in freshwaters.”

Article link, January 2015

2. Why are global crayfish populations declining?


Image: Flickr | coniferconifer | Creative Commons

“A third of global freshwater crayfish populations are threatened with extinction, according to a newly published report.  A large team of researchers from the UK, Ireland, USA, Mexico, Australia and Austria, led by Nadia Richman at the Zoological Society of London, evaluated the extinction risk of the world’s 590 freshwater crayfish species based on the IUCN Red List categories.

32% of global crayfish species were classified by the team as ‘at risk of extinction’, a figure far higher than for most marine and land-dwelling animals and plants.  This high extinction risk is unlikely to be helped by the fact that only a small proportion of global crayfish populations are covered by existing protected areas for conservation.”

Article link, January 2015

3. MARS Podcast: an interview with Professor Steve Ormerod

“Join us on the banks of the River Brun in Burnley in North West England to meet Steve Ormerod, Professor of Ecology at Cardiff University, chair of the RSPB council and co-leader of the MARS project catchment segment.

On a cold, blustery spring morning with dippers flitting past and robins singing in the trees, Steve tells us about the history of the Brun, and its recent restoration after years of pollution.  Steve explains the concepts of freshwater stressors and ecosystem services, and tells us about his work with MARS.”

Article link, March 2015

4.Nutrient pollution can harm stream ecosystems in previous unknown ways


A North Carolina forest stream. Image: Jenn Deane | Flickr Creative Commons

“It has long been known that nutrient pollution – the overloading of chemicals such as nitrogen and phosphates from sources such as agricultural fertilisers – can have potentially harmful effects on freshwater ecosystems.  In particular, eutrophication – the rapid growth of algal ‘blooms’ – can starve the aquatic environment of light and dissolved oxygen, prompting shifts in the form and function of the ecosystem, and potentially causing collapses in populations of other freshwater plants and animals.

However, a new study published in the journal Science by a team of researchers from the University of Georgia, USA suggests that nutrient pollution can also prompt significant losses of carbon from forest stream ecosystems, which in turn reduces their ability to support aquatic life.”

Article link, April 2015

5.The State of Nature in the EU: an unfavourable picture for freshwaters


Avon Meadows Community Wetlands in Worcestershire, England have been created on the rural-urban fringe to encourage biodiversity, reduce flooding and improve water quality on the nearby River Avon. Image: Geoff Moore | Flickr | Creative Commons

“Last week the European Environment Agency released their ‘State of Nature in the EU‘ report, which uses comprehensive data collected across the continent between 2008-2012 assess the status of and trends in biodiversity and natural habitats across Europe.  Data on Europe’s species and habitats was collected by individual countries (or member states) as part of monitoring for the Birds Directive and the Habitat Directive – European environmental policies designed to help guide conservation, protected area management and environmental restoration across the continent”

Article link, May 2015

6. Discovering the Dragonflies and Damselflies of Eastern Africa

Stellenbosch 2013

Spesbona angusta, a damselfy thought to be endemic to the Western Cape, South Africa. First named Metacnemis angusta in 1869, this damselfly was thought extinct between 1920 and 2003 when a small population was rediscovered near Cape Town. Image: Jens Kipping

“Dragonflies and damselflies (or Odonata as commonly termed) are some of the most fascinating and beautiful freshwater species in the world.  Exhibiting a huge variety of eye-catching colours and with wings flecked with unique patterns, Odonate species live in most parts of the world, laying their eggs in and around bodies of water, and commonly seen flitting about reeds and lily pads on the fringes of lakes, rivers and wetlands.

A comprehensive new book documenting the dragonflies and damselflies of tropical East Africa has recently been published, co-written by Klaas-Douwe ‘KD’ Dijkstra from the Naturalis Biodiversity Center in The Netherlands and Viola Clausnitzer at the Senckenberg Museum of Natural History in Germany. The product of fifteen years of fieldwork, research and writing, The Dragonflies and Damselflies of Eastern Africa is the first handbook of its extent and detail on tropical Odonata.”

Article link, June 2015

7. Underwater sound pollution leaves juvenile European eels vulnerable to predators


A heavily laden container ship: what effects will the sound pollution it emits have on underwater life? Image: four12 | Flickr | Creative Commons

“Many of us know about the familiar sources of water pollution: fertilisers running off agricultural fields, sewage leaking from underground pipes and oil and fuel leaking from boats, amongst many others.  But what if the pollutants and stresses on aquatic environments weren’t chemical and visible, but sonic and audible?  How might noise pollution affect underwater life, and how might we manage it?  How, in fact, in a crowded, noisy world do we even define what noise pollution might be?

A recent study published by Stephen Simpson and colleagues at the Universities of Exeter and Bristol in England investigated how the noise made by ships affects the behaviour of juvenile European eels. They found that underwater sound pollution significantly affects the behaviour of juvenile eels in ‘life or death’ scenarios when ambushed or pursued by a predator.  Their findings suggest that sound may need to be increasingly taken into account when assessing the multiple pollutants and stressors that aquatic life is exposed to, both in oceanic and freshwater ecosystems.”

Article link, June 2015

8. Microplastic pollution: an emerging freshwater stressor


Microplastics found in the Magothy River, Chesapeake Bay, USA. Image: Chesapeake Bay Program | Flickr Creative Commons

“In recent years, microplastic pollution has been identified as an increasingly pervasive and damaging environmental stressor in the world’s seas, found even in remote locations in the Arctic ocean and deep sea trenches, far from human settlements.

Microplastics are, as the name suggests, tiny particles of plastic (less than 5mm in size in this study) which enter aquatic environments either directly as manufactured pellets from industrial and farming processes and microbeads from cleaning and cosmetic products; or indirectly through the erosion and breakdown of larger plastic items such as fishing nets and household waste.  When ingested by fish and marine mammals, microplastics can obstruct or damage internal processes, cause bodily stress, and potentially lead to the uptake of harmful chemicals.

A paper published earlier this year in the journal Water Research, led by Dafne Eerkes-Medrano at the Aquatic Ecology Group, Department of Zoology at the University of Cambridge provides a timely overview of research on the impacts of microplastics on freshwater systems.”

Article link, June 2015

9. The state of scientific knowledge on aquatic multiple stressors


MARS scientists studying multiple stressors in Lake Beyeshir, Turkey. Image: METU Limnology Laboratory

“New scientific research suggests that multiple stresses – chemical pollution, drought, floods, habitat destruction amongst many others – can interact in complex and dynamic ‘cocktails’. These interactions may intensify their individual effects on freshwaters: in other words, the combined damage multiple stressors cause to ecosystems may be more than the sum of the individual parts (known as a synergistic effect).

As studies such as this one by Daniel Hering and colleagues from earlier in the year suggest, multiple stressors pose a series of new, complex and non-linear challenges for aquatic ecosystem conservation and, increasingly, restoration. But despite this emerging awareness of the challenges multiple stressors pose to the health of freshwater ecosystems, there are comparatively few scientific studies which provide quantitative evidence on their effects, making it difficult to inform suitable management and mitigation strategies.

Responding to this shortfall in knowledge, a team of MARS scientists led by Peeter Nõges from the Estonian University of Life Sciences, reviewed 219 existing scientific papers, published since 1986, which quantify the prevalence and effects of multiple stresses on river, lake, groundwater and estuary environments.”

Article link, July 2015

10. an online database for European freshwater species

Screen shot 2015-07-06 at 10.40.18

“In recent years, numerous European environmental policies have been implemented to protect, conserve and restore the continent’s freshwater ecosystems. Two key pieces of European legislation, the Habitats Directive and the Water Framework Directive, have a strong focus on biodiversity. In the Water Framework Directive (first implemented in 2000), analyses of different “biological quality elements” are used to assess the ecological health and status of water bodies (predominantly using data on biological traits and ecological preferences of freshwater species), which in turn guides funding for conservation and restoration work.

As a result, to properly implement such environmental policy requires comprehensive and detailed information on freshwater species. However, until now, such data has largely been scattered, incomplete and not comprehensive: varying widely in quality and precision. To address this shortfall, the database has been set up to provide comprehensive and harmonised data on the ecological characteristics of European freshwater species, which can be used by scientists, policy makers, environmental managers, students and the public.”

Article link, July 2015

11. The MARS ‘cookbook’ for assessing freshwater multiple stresses and ecosystem services


River Great Ouse in arable farmland. © Copyright Hugh Venables and licensed for reuse under this Creative Commons Licence

“The MARS project assesses the impacts of multiple stressors on the provision of ecosystem services from freshwater ecosystems, under different climatic and land-use scenarios. The project has developed an innovative new assessment methodology – termed a ‘cookbook’ – to allow scientists, environmental managers and policy makers to quantify the relationships between multiple stresses and ecosystem service provision and value. The cookbook provides an invaluable tool to support the implementation of the Water Framework Directive in Europe.”

Article link, August 2015

12. Wildlife photographer Neil Phillips captures the curious and beautiful diversity of underwater life


An unfamilliar view of a familiar creature: the common backswimmer (or water boatman). Image: Neil Phillips

“For a while now, we’ve been enjoying fantastic wildlife photographs taken by Neil Phillips and posted on his @UK_Wildlife twitter page.  Many of Neil’s photographs capture otherwise unseen views of underwater life, providing a window into this diverse and often beautiful submerged world.

In many ways, Neil’s photographs demonstrate a shared goal between freshwater science and art: that is through a curiosity to document and bring to life the patterns and processes of underwater life, largely obscured to the naked eye.  As you can see above, Neil’s macro photography can make even familiar creatures like the water boatman seem newly fascinating, curious and strange.”

13. What influences the ecological success of river restoration?


A section of the renaturalised River Emscher in Germany. Image: DESSIN Project

“River restoration schemes take a range of different approaches. Many restoration projects attempt to recreate ‘natural’ river processes and features such as flow amount and speed, stream depth and width, meanders and riffles. Another common restoration approach is to remove human barriers such as weirs and dams to improve continuity and connectivity between different habitats along a river’s course.

Other restoration approaches focus on the areas of land around rivers, planting strips of riparian vegetation along the river, to buffer pollutants and sediment from reaching the river, or using environmental policy to reduce groundwater abstraction from agriculture and industry.  And finally, some restoration schemes focus on reintroducing plants and animals that have been lost over time – for example beavers or juvenile salmon.  Most river restoration schemes use a combination of these approaches, depending on the individual river to be restored, its ecological and social histories, and the various priorities for restoration outcomes.

But as yet, there is little synthesised information on the factors that influence the success of river restoration initiatives across the world.  However, a new study bringing together all the available global scientific literature and data on the ecological effects of river restoration, led by Jochem Kail from the University of Duisberg-Essen in Germany and published in Ecological Indicators, may help shed new light on this shortfall, and help guide environmental managers in designing restoration work.”

Article link, September 2015

14. Ecological surprises: why multiple stressors in freshwaters may cancel each other out

Algal blooms in the Lake of Menteith, Scotland. Image: Dr Richard Murray | Creative Commons

“Stressors are environmental changes that place stress on the health and functioning of an ecosystem.  There is increasing evidence – largely from marine environments – that multiple stressors may interact to produce unexpected effects on aquatic ecosystems.  However, there is a pressing need to better understand the ‘ecological surprises’ caused by multiple stressors in freshwater ecosystems (a point made in papers by MARS scientists Steve Ormerod in 2010 and Daniel Hering and colleagues in 2015).

Existing scientific literature from marine environments show that multiple stressors can have effects that are greater than the sum of those caused by individual stressors.  This ‘synergistic’ interaction poses important questions for environmental managers and policy makers.  In short, it is difficult enough to manage individual stressors such as pollution, habitat destruction and overfishing, without the unexpected and, as yet, largely unpredictable interactions and effects these stressors might have.

In the light of this uncertainty, a team of researchers from the University of Pretoria in South Africa and the University of Alberta in Canada analysed data from 88 existing scientific studies that show the responses of freshwater ecosystems to pairs of stressors.  The team, led by Michelle Jackson from the University of Pretoria, brought together the findings of these studies to investigate the characteristics and effects of different stressor interactions; and the extent to which interactions vary between different stressor pairs and response measurements.”

Article link, September 2015

15. Water and Climate Change at COP21 in Paris


Delegates at the Water Resilience Focus event organsied by the Lima to Paris Action Agenda. Image: UNFCCC

“This week and next, governments, policy makers and NGOs from around the world are meeting in Paris to work towards a new international agreement on climate change intended to keep future global warming below 2°C. The 21st Conference of the Parties to the United Nations Framework Convention on Climate Change (or COP21) takes place in a year declared the hottest on record by the World Meteorological Organisation.

Water is an key medium through which climate change affects human and non-human lives.  Climatically-altered precipitation patterns, extreme weather events (and ensuing floods and droughts), and shifting water temperatures all contribute to alterations in the quality and quantity of freshwater available to humans, plants and animals in ecosystems around the world.”

Article link, December 2015

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