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River restoration in action: a chalkstream in Southern England

September 2, 2016

River restoration is an important strategy used to reduce the impact of multiple stresses on freshwater ecosystems.  However, its not always possible to see the restoration process in action.

A recent film made by the UK-based Five Rivers environmental consultants documents the restoration of Ford Mill, a chalkstream in Southern England, providing a fascinating insight into approaches for river restoration.

The short film shows the removal of barriers to fish movement, the creation of fish passes and the re-meandering of historically straightened channels.  Returning to the stream one year on, biodiversity is flourishing in a range of newly (re)created habitats.

Read more about Five Rivers restoration projects here.

Freshwater Protected Areas in a Rapidly Changing World

August 22, 2016

Tenaya Lake in Yosemite National Park, USA. Image: nrg_crisis | Flickr Creative Commons

Protected areas are one of the key conservation tools used by environmental managers and policy makers across the world to help protect biodiversity and ecosystems.  Protected areas (for example Sites of Special Scientific Interest in the UK) set aside blocks of land and water in which human activities – such as fishing, farming, hunting and building – are limited as a means of promoting the survival of often rare and valuable species and ecosystems.

Protected area designation has been a popular mode of conservation practice throughout the latter half of the 20th century (though not without debate over their effectiveness and appropriateness).  Over the coming years, the expansion of protected areas is a project that global governments have signed up for through the Convention on Biological Diversity Aichi ‘Targets for 2020’.  These targets are embedded in European environmental policy through the EU 2020 Biodiversity Strategy.

Protected areas have been designated for freshwater conservation with mixed success across the world.  As Ben Collen and colleagues demonstrated in an (open-access) 2014 research paper, global freshwater biodiversity continues to decrease at an alarming rate, despite targeted conservation strategies.  And as Charles Vörösmarty and colleagues wrote in 2010, projected changes to the global climate mean that some freshwater species may struggle to persist in ecosystems in which they currently live, as their ‘climatic niche’ shifts, or even disappears.

Vörösmarty and colleagues suggest that nearly 80% of the world’s human population is exposed to high levels of threat to water security: that is, that climate change may make their water provision scarce or irregular in the future.  Clearly, freshwater protected areas face a growing set of challenges, not least to protect biodiversity and ecosystems that are open to change and move, under increasing global human demands for water.

Addressing these challenges, a recent special issue of Aquatic Conservation: Marine and Freshwater Ecosystems compiles a set of articles examining the aims and effectiveness of freshwater protected areas globally.  Edited by Vigilio Hermoso, Robin Abell and Simon Linke, the open-access special issue contains articles on protected areas for endemic biodiversity in the Western Ghats, India; on integrating multiple stakeholder perspectives in protecting a water-stressed ecosystem in the Murray-Darling Basin, Australia; on climate change threatened endemic biodiversity in Amazonia; and on the relationships between protected areas and global water security.

The issue authors identify that emerging conservation approaches which frame humans as an inextricable part of ‘nature’ offer new opportunities to enhance the value of protected areas for freshwater conservation.  Under this ‘people and nature’ paradigm, the authors suggest that “the imperative of finding solutions that generate co-benefits alongside biodiversity conservation, and the clear reliance of human communities on freshwater services, has created an environment that may be more favourable to protected areas focused in whole or part on fresh waters.”

A number of broad thematic threads run through the special issue.  Freshwaters are unique environments: they flow, flood and alter over space and time, and as such, protected areas need to be designed to be able to function under such fluxes.  Freshwaters are often highly connected, supporting species of fish, animals, plants and insects that may migrate across watersheds, either in regular patterns (e.g. for breeding), or in response to changes in habitat niches due to climate change or human pressures.  Pollution and other pressures can be similarly trans-boundary, particularly in rivers, where human activities upstream can place stress on the health of downstream ecosystems.

Similarly, freshwaters are often highly connected to the dynamics of the wider terrestrial (or land-based) environments that they drain.  As such, the health of freshwater ecosystems is often closely linked to the health of the wider landscape.  Accordingly, there is a tension between the need to protect the freshwater ecosystems which have, for example, high biodiversity value, with the need to reduce potential pressures (e.g. diffuse pollution) across the wider landscape. Given these considerations, monitoring programs are essential in assessing the effectiveness of protected areas for freshwater systems, and in providing the evidence for policy decisions and adaptive environmental management.

The final paper in the special issue, by Diego Juffe-Bignoli and colleagues, is something of a synthesis and horizon-scan for these issues.  The authors outline that despite the CBD Aichi Biodiversity Target 11 stipulating an improved global protected area network including freshwater ecosystems by 2020, as yet there is no comprehensive assessment of what needs to be achieved to meet Target 11 for freshwater biodiversity.

Aichi Target 11 reads:

By 2020, at least 17 per cent of terrestrial and inland water areas and 10 per cent of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services, are conserved through effectively and equitably managed, ecologically representative and well-connected systems of protected areas and other effective area-based conservation measures, and integrated into the wider landscape and seascape.

Juffe-Bignoli and colleagues outline a number of recommendations about how such a target might be met, and more broadly, how a protected area network for freshwaters might be improved.  They advocate the need for globally consistent and comprehensive methods of defining the boundaries of freshwater ecosystems, as a means of accurately measuring the extent covered of protected area coverage.

They state that it is crucial to identify areas of importance for freshwater biodiversity and/ or ecosystem services (using existing approaches such as Key Biodiversity Areas) to guide the designation of new protected areas.  They argue that protected areas should take into account a diverse range of stakeholders, representing the needs of both human and non-human life, in a process of ‘equitable management’.

Perhaps crucially, Juffe-Bignoli and colleagues suggest that there is need for better spatial tools to assess connectivity of freshwater systems, as a means of designing connectivity into protected area networks.  This process is to an extent seeking to ‘future proof’ protected areas given the prospect of future climatic changes.

This is perhaps the key challenge for freshwater protected areas: to provide interconnected refuges for biodiversity in an increasingly pressured and changeable world.

You can read and download the full open-access special issue of Aquatic Conservation: Marine and Freshwater Ecosystems here.

What Works in Freshwater Conservation?

August 16, 2016
lakenheath fen 3

Lakenheath Fen, where wetland and reedbeds were restored on arable land in the 1990s, and which now supports rich biodiversity. Image: Claire Wordley

Last year, the Conservation Evidence group at the University of Cambridge published a book titled ‘What Works in Conservation‘. Published as both hard copy and open-access pdf, the book compiles cutting-edge research assessing the effectiveness of conservation measures in protecting and improving the world’s ecosystems.

The publication contains information on different freshwater conservation measures relating to amphibians, aquaculture and invasive species, and provides a valuable source for environmental managers assessing evidence-based conservation strategies.

Intrigued, we spoke to Dr Claire Wordley of the Conservation Evidence group to find out more.  She gave this fascinating overview to the project.


What Works in Conservation is a book with a simple but important aim: to provide the scientific evidence for conservation actions, enabling conservationists to see, well, what works in conservation. It is part of the work by the Conservation Evidence project, set up by Professor Bill Sutherland at the University of Cambridge to break down the barriers between conservationists and the evidence they need to do their jobs.

In conservation, we currently have a huge divide between academics publishing more and more papers with conservation implications, and on-the-ground conservationists, who often can’t access those papers and don’t necessarily have the training to read scientific jargon anyway.

Conservationists often miss out on information in academic journals. Academics often pursue scientifically interesting questions at the expense of those that are useful to conservationists. Conservation actions are often taken but not monitored, and the results not published, reducing the capacity for the conservation community to learn from each individual’s experience.

The result is that conservation is not as effective as it could be. Disciplines such as medicine, international aid, social policy and education are increasingly evidence-based, with many of them seeing huge improvements in effectiveness; it’s time for conservation to do the same.

Conservation Evidence is working to provide an ambitiously large and comprehensive global evidence resource, freely available to conservation practitioners, policy makers and anyone else who is interested. The group tackles each topic as a synopsis on a certain taxon, ecosystem or topic. So far, synopses have been produced on bees, birds, bats, amphibians, sustainable aquaculture, soil fertility, control of freshwater invasive species, natural pest control, farmland conservation (in Western Europe) and forests. These are available as books or PDFs, or as a searchable database.

What Works in Conservation, published in 2015, summarises the evidence from most of these synopses – an update will be published in 2017. Each action in What Works has been put into a category of effectiveness, such as ‘beneficial’ or ‘likely to be ineffective or harmful’. This scoring system has also been applied to much of the searchable database.


A swimming toad. Image: Claire Wordley

So, what works in freshwater conservation? Well, a freshwater conservation synopsis will be underway imminently in collaboration with Tour de Valat, but there is still a fair amount on the Conservation Evidence website that is relevant to freshwater conservationists. The amphibian synopsis provides the published scientific evidence for a whopping 129 actions, such as adding lime to water bodies to reduce acidification, deepening, de-silting or re-profiling ponds and using antifungal treatment to reduce chytridiomycosis infection. Some of these have huge relevance to the practices undertaken on a daily basis by ecological consultants, such as translocating great crested newts.

The control of freshwater invasives synopsis (some of which is in What Works, the rest of which is available online) has 118 actions to control six invasive species from American bullfrogs to water primrose (we are currently working on additional species). Looking at the freshwater invasives synopsis, it is striking that the same intervention can affect different species in very different ways. For example, introducing predators for American bullfrogs was scored likely to be beneficial, while introducing predators for Procarambus crayfish was considered unlikely to be beneficial.

This highlights the need to collect evidence for each intervention we are trying to deliver, rather than going on the basis of ‘common sense’. Unfortunately, as in medicine, some very sensible sounding ideas can be ineffective, or worse, kill the patient.

Browse the evidence for yourself, and where there is no evidence for an action, take it as a call to arms to collect some yourself and publish it. Together, we can make conservation better.

Stepping-stones for diversity: ponds and landscape conservation

August 11, 2016

A London pond. Image: Derek Winterburn | Flickr Creative Commons

For many people, ponds can be familiar and everyday freshwater habitats; small patches of water – both natural and man-made – found in gardens, parks, nature reserves and even dense urban areas.

Ponds aren’t just places to feed the ducks or sail toy boats, however, as an growing body of scientific research shows that they are valuable habitats for biodiversity, often for rare and endemic species, and particularly in ecologically-poor urban and agricultural landscapes.

Ponds help generate a range of ecosystem services.  They can help buffer flood waters through storing excess rainfall, and similarly retain nutrients and sediments that might be washed away by flood water runoff.  Vegetation growth – most notably of reed beds – can provide local-scale storage of carbon, and help cool urban heat island effects.

However, despite their role as beacons for freshwater biodiversity in highly-altered landscapes, ponds are often overlooked by conservation and policy initiatives.  The EU Water Framework Directive – which requires European member states to improve water quality to ‘good status’) only covers lakes larger than 50ha (roughly 60 football fields in size – in other words ‘big lakes’).  Similarly, only a small number of pond habitats (e.g. Mediterranean temporary ponds) and freshwater species (e.g. the Great Crested Newt, Triturus cristatus) are designated for protection under the EU Habitats Directive.

As a result, ponds are often overlooked and poorly conserved; regularly drained and filled in during building work, or used as dumping grounds for waste, pollutants and invasive species (such as unwanted pets).

However, there is an increasing movement within freshwater ecology and conservation circles to better document and protect pond habitats.  In the UK, the Freshwater Habitats Trust has placed pond conservation at the centre of its work, most notably through the ongoing People, Ponds and Water project.  For the Trust, pond conservation is an participatory process, involving local communities to document, champion and even create new pond ecosystems. We covered their report on small water bodies on the blog in 2014.

Freshwater scientists are increasingly turning their attention to diversity and importance of pond ecosystems, too, with a burgeoning number of journal papers published over the last decade or so.  In an influential 2014 paper in Hydrobiologia, Régis Céréghino and colleagues report on discussions within the European Pond Conservation Network, to suggest that ponds are likely to become ever more important in creating connected landscapes in a changing climate, “Beyond the contribution of individual ponds to the aquatic and terrestrial life, connected networks of ponds are vital as a response to global climate change, by allowing the northward and/or upward movements of species.”

A new paper published in Biological Conservation by Matthew Hill and colleagues studying macroinvertebrate (or aquatic insect) diversity in rural and urban ponds provides more evidence to this growing knowledge base.  Hill and colleagues sampled 91 lowland ponds in the English Midlands, across 3 land use types: floodplain meadows, arable and urban ponds, finding over 200 different macroinvertebrate species.

Whilst floodplain ponds supported the greatest macroinvertebrate diversity, those in arable and urban landscapes also held rich insect life, including species of high conservation value.  A key finding of this study, therefore, is that ponds are important micro-habitats for biodiversity at a landscape scale.  What this means is that whilst floodplain ponds are (perhaps as expected) the most diverse of the three habitats, all the ponds together generate cumulative, connected species diversity in otherwise ecologically-poor landscapes.

Conservationists across the world are increasingly focusing their attentions on conservation within the ‘landscape matrix’.  This is an approach that doesn’t only focus on sites of high biodiversity or rare species inside protected areas, but instead seeks to understand, value and protect (often micro-) habitats such as ponds which provide refuges or ‘stopping-off points’ for biodiversity in highly altered landscapes.

As the Freshwater Habitats Trust have demonstrated, the presence of ponds in many people’s everyday landscapes mean that they have a valuable role in potentially connecting the public to issues of freshwater health and conservation.

As yet though, their small size and visibility means that ponds are continuing to ‘slip through the net’ of freshwater policy and conservation initiatives.  The new study by Hill and colleagues concludes with a call for a renewed focus on ponds within environmental legislation, and a suggestion that such a ‘landscape approach’ to understanding their value  in ecologically-poor environments may be the most appropriate way to help ensure their conservation (and creation) in the future.

So, perhaps next time you pass by your local pond, why not stop and look a little longer: the diversity of life you see might surprise you.

Christian Feld on ‘What Can I Do to Help Freshwater Ecosystems?’

August 4, 2016
Red-eared turtles in Lake Baldeney, Essen, Germany. Image: Christian Feld

Red-eared turtles in Lake Baldeney, Essen, Germany. Image: Christian Feld

Last week we began a new series of posts titled ‘What Can I Do to Help Freshwater Ecosystems?‘, in which freshwater experts suggest ways in which the public can help conserve rivers and lakes.  Today we have another post from MARS scientist Christian Feld, which draws on his experiences introduced red-eared turtles to freshwaters around Essen in north-west Germany.


Essen is the centre of a large metropolitan area, called the “Ruhrgebiet” (after the river Ruhr), where around five million people live.

Many of Essen’s inhabitants do not know nature particularly well, often because they haven’t seen too many natural parts of the country. You have to drive an hour at least to see some nice forests. For natural rivers and lakes, you have to drive three hours or more. For many people in Essen this prevents any sort of meaningful interaction with nature.

Now a story: A pet is a pet is a pet

Many children like owning and caring for pets, whether birds, mice, rabbits, turtles. When both pets and children grow older, there is often less enthusiasm to care for the pets. Then, many of these domesticated animals are released in nature.

At Lake Baldeney, south of Essen, we’ve a huge population of red-eared turtle (Trachemys scripta elegans). They come from the Great Lakes in the U.S. and have been introduced to Europe through the pet trade.  They’re sold for €20–30 (only!) and grow up to 50 years. Thus, it is very likely that they won’t live as pets for long, but will be released after a couple of years. Red-eared turtles have spread across the world, and can out-compete native biodiversity for food and habitat, causing significant stress to the health of freshwater ecosystems.

The red-eared turtle is just one example of a freshwater alien species. There are many more – animals as well as plants. They may threaten native biodiversity. They may affect ecosystem’s health and intactness. And finally they may affect us humans.

So what can we do about alien and invasive species? Well, first, we need to take responsibility for our pets. A pet isn’t something you discard after you ‘used’ it for a while. Right now it’s summer time – holiday time. This is the time you may find many more pet animals abandoned or released into nature because they cannot be taken on holidays.

Second, we need to care about alien species. We need to know them and we need to know what they can do to us and our rivers and lakes.

And third, we must respect nature, which gives us so many services and benefits. In general, people shouldn’t interfere with already stressed freshwaters by introducing species that aren’t native to ecosystems. And children should be encouraged to have respectful and inspirational interactions with nature.

This, is what we can do for nature.

Marko Järvinen on ‘What Can I Do to Help Freshwater Ecosystems?’

July 26, 2016

A Finnish river in winter. Image Ville Lukka | Flickr Creative Commons

Living an environmentally conscious lifestyle can sometimes seem overwhelming. There are so many ways in which humans are changing and damaging the natural world that it can be difficult to know how to take positive steps in reducing your own impact.

This is particularly the case for freshwater ecosystems, which are increasingly abstracted, channeled, polluted and fragmented by humans.  However, there are many small-scale actions that we can all take in our daily lives to help reduce our negative impacts on freshwater health and biodiversity.

Today we start a new series of short posts titled ‘What Can I Do to Help Freshwater Ecosystems?’  which suggest ways in which our daily lives might become more ‘water aware’.

Our first contribution is from MARS scientist Marko Järvinen from the Finnish Environment Institute (SYKE) Freshwater Centre.


And awareness of the state of one’s local water bodies is likely to increase your personal interest in maintaining and improving freshwater health. For instance, in Finland environment authorities provide information on the state of our surface waters on the web.

Citizens can download their own observations of water temperature, cyanobacteria bloom situations, certain alien species etc. from the web (from their local lakes or during sailing, etc.) using the web-based service Järvi-meriwiki. Members of the public can also download their observations to this wiki-system via a smart phone application.

In Finland we have around 720 000 summer cottages and many of these are located next to a lake, river or the coastal Baltic Sea, including the archipelago. As a result freshwater health concerns most Finnish people. Almost all summer cottages have a sauna, so the handling of sauna bathing water is one issue.

Another way for the public to help improve freshwater health is to attend local lake and river management activities. In Finland, SYKE is coordinating a network of lake and river restoration workshops where environment authorities, experts from municipalities and common people share and learn their experiences.


If you’d like to contribute to the series, you can email us on info{at}

Can we geo-engineer polluted freshwaters back to health?

July 20, 2016

Green algal bloom forming a thick surface layer in Lake Dora, Florida. Image: Nara Souza | Florida Fish and Wildlife Commision | Creative Commons

‘You broke it, you own it.’  That was political ecologist Paul Robbins’ take on the results of a new experimental trial (open-access) at the University of Alberta, Canada where adding iron to eutrophic lakes was found to help manage outbreaks of harmful algal blooms.  For Robbins (and others, such as the Ecomodernist movement), the damage humans have caused to the natural world means there is a pressing need for radical and often-interventionist management to reverse decades of ecological harm.

The University of Alberta experiments suggest that one way to positively ‘own‘ damaged freshwater ecosystems is through geo-engineering, the deliberate large-scale intervention in the Earth’s natural systems to counteract environmental damage (most often climate change).

In this case, the additions of iron in the Alberta study would be unlikely to occur in a ‘natural’ ecosystem, but given that we are living in a world where it is arguably impossible to find ‘pure’ nature (see for example, landscape historian Bill Cronon’s work (pdf), and recent debates over the Anthropocene), such an intervention may be justified in terms of the positive ecological impacts it may have.  In other words, geo-engineering finds novel strategies to help guide novel ecosystems towards (potentially new) states of health.

Freshwaters comprise some of the most highly altered and modified ecosystems in the world: new concrete geologies and diluted chemical flows.  In this context, a new special issue of the journal Water Research brings together 60 scientists from across the world to present findings on the effectiveness of geo-engineering approaches in managing the harmful effects of phosphorous pollution in freshwaters.

One of the special issue editors, Kasper Reitzel, from the Department of Biology, University of Southern Denmark outlines the pressing need for effective phosphorous management, stating that,  “In 40 % of Europe’s lakes the water quality does not meet the demands of EU’s Water Framework Directive, mainly due to phosphorus pollution. That is a huge problem for biodiversity and society and we need to put an effort into developing effective approaches to restore these lakes.”

Phosphorus is a major cause of water quality degradation across the world.  Reaching freshwaters through run-off from farmland fertilisers and feeds, industrial chemicals and domestic cosmetics and wastewater, phosphorous can create ecological “dead zones” and toxic algal blooms which can then cause biodiversity losses and increased health risks for the plants, animals and humans that come in contact with polluted waters.

Phosphorous pollution is particularly pervasive as it often accumulates in lake bed sediments.  This means that the ecological health of a lake may take many years to recover, even when phosphorous pollution is controlled, as particles stored in the sediments are gradually released back into the lake water.

This poses a number of challenges for freshwater management, both in the short-term (restricting phosphorous pollution); and in the long-term (managing the effects of phosphorous deposits on an ecosystem). Geo-engineering approaches have been used for a number of years in freshwaters, for example in adding aluminum salts or modified clays into a lake to lock excess phosphorus stored in the sediments.

However, the results have not always been effective, according to special issue editor Sara Egemose from the Department of Biology, University of Southern Denmark, who says, “Often lake managers have used geo-engineering uncritically in lakes where the external loading of phosphorous was not reduced enough, or they have applied too low a dosage because of economic restrictions.”

The new Water Research special issue presents findings of laboratory experiments, field studies and meta-analyses of existing research.  The geo-engineering techniques assessed include the use of modified clays and soils (e.g. with the chemical element lanthanum), coal fly ash, dissolved organic carbon, and flocculants which cause fine organic material (such as cyanobacteria) to clump together for removal. Aluminium and lanthanum modified compounds were among the most effective compounds for targeting phosphorous, whilst flocculants and ballast compounds may be used as short-term measures to clump and sink cyanobacteria blooms.

Whilst many of these techniques are shown to be successful in either mitigating phosphorous build-up or managing the resulting algal blooms, they are often expensive and difficult to apply across large areas.  As such, the issue editors emphasise that an ecosystem analysis that reveals the main water and phosphorous flows and the biological structure of the waterbody should be the first step of any management strategy so that geo-engineering approaches are effectively targeted.

The issue editors suggest that new technological developments in the use of modified zeolites – absorbent aluminosilicate minerals – may offer future possibilities for treating both phosphorous and nitrogen pollution simultaneously.  To maximise the potential of such emerging geo-engineering approaches in treating (or even reversing) human damage to freshwaters through nutrient pollution, the editors conclude with a call for the establishment of a new multi-national, interdisciplinary research centre for freshwater geo-engineering.

Special Issue on Geo-engineering to Manage Eutrophication in Lakes (2016), Edited by Miquel Lürling, Eleanor Mackay, Kasper Reitzel and Bryan M. Spears, Water Research, Volume 97, pp. 1-174

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