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Community-based conservation of arapaima and giant turtles in the Amazon Basin

January 14, 2019

The arapaima, a fish native to the Amazon Basin which can grow to over three metres in length. Image: Lynn Chan | Flickr Creative Commons

Arapaima are one of the world’s most unique freshwater animals. A true ‘megafauna‘ species, these huge fish (which can grow to more than three metres in length) are native to the to the Amazon and Essequibo basins of South America.

Arapaima habitats change in depending on water levels, and these freshwater giants can become trapped in small floodplain lakes during the dry season. However, their ability to breathe air using a specially-adapted swim-bladder allows the arapaima to survive, even in such low-dissolved oxygen environments. As a result, the arapaima must periodically rise to the surface, which makes it vulnerable to fishing pressures. However, scientists do not have enough data on the health and distribution of arapaima populations to accurately assess their conservation status.

The arapaima is an important cultural animal for local communities in the Amazon and Essequibo basins, whether as a foodstuff, source of medicine (its tongue) and clothing (its skin); or as the inspiration for stories and folktales. As a result, there is increasing interest in community-based approaches for conserving arapaima populations.

Last year, Brazil’s prestigious national science prize for the best PhD thesis  was awarded to Joao Vitor Campos-Silva for his research entitled “Community-based management of Amazonian giants”. On a recent trip to Brazil, Paul Jepson – former manager of this blog with BioFresh, and now Nature Recovery Lead at Ecosulis – caught up with Joao to find out more.


Paul Jepson: Congratulations on your prize. This year’s topic was biodiversity conservation and social transformation. What do you think it was about your research that impressed the judges?

Joao Vitor Campos-Silva: Brazil, like many countries is searching for new models and paradigms to reconcile nature conservation and development. My research assessed the ecological and quality-of-life outcomes of two large community based-management initiatives in the Amazon linked to arapaima and freshwater turtles.

Scientific research often seems to provide yet more evidence of declines, however based on long-term participating monitoring data I was able to show that arapaima and freshwater turtle numbers have rebounded and the communities are flourishing. I think the judges liked the fact that I was telling a positive story of how a community had transformed the way they managed freshwater resources, and how the recovery of these resources is opening new community opportunities.


The arapaima (Arapaima gigas) is the largest scaled freshwater fish on Earth. It evolved in the ancient Lake Pebas which had low oxygen concentrations. For this reason the arapaima evolved to be an air breather. It is nowadays restricted to the Amazon flood plain and reaches weights of 220 kg, although historical books report specimens up to 350kg. Image: Carlos Peres

PJ: Tell us more about the community whose management you researched and the arapaima. What is the ‘communities approach’ to arapaima management and how did it come about?

JC-S: The arapaima is an awesome fish – it is like a monster and people are very curious about it. People from outside Amazonia wonder how it can be caught. Among the Amazon people it has huge cultural importance: one origin myth believes that people and arapaima came from the same brothers! It seems to be something of an icon for everyone. During the 1970s fishing vessels from outside arrived to catch arapaima and freshwater turtles. As well as causing steep declines in the populations of these species, lots of other fish species were caught threatening the local community’s food security.

Community leaders in the Medio Jurua – the area I studied – heard about a community arapaima management approach being developed in the Mamirauá Sustainable Development Reserve, 2000 km away. Briefly, local fishermen in Mamirauá told a fishery scientist called Leandro Castello that they knew a way to count arapaima, and together they developed a robust survey method. At the time the government was establishing sustainable use reserves and promoting zonation approaches.

In the Medio Jurua region a social organisation had formed in response to the rubber tapper movement of the 1970s, and they helped communities to organize to zone lakes, agree catch rules and organized the sale of arapaima and other natural resources to external markets.

PJ: So how did you get involved in the area and what were your research motivations?

JC-S: I started to work at Jurua River 10 years ago. After completing my masters, I got a job with the government of Amazonas State to coordinate participatory monitoring initiatives in their sustainable use reserves. Through this role I got to know Prof Carlos Peres who is a leading Amazonia researcher based at the University of East Anglia in the UK.

I saw that Jurua river was a bright spot in Amazon conservation, where the model of social organization offers hope and optimism for combining biodiversity protection with improvements in people’s local well-being. Prof Peres and I secured a Darwin Initiative grant and this enabled me to enroll for a PhD and make a comprehensive study.


Arapaima on jetty. Arapaima are caught with nets and harpoons. The local social association has purchased a purpose-built boat with ice storage to transport arapiama to the city of Carauari from where they are transported by river to Manaus – a 10 days journey. Image: Carlos Peres.

PJ: Your 2016 paper in Scientific Reports demonstrated remarkable recoveries in arapaima populations as a result of management. Tell us about the scale of these recoveries and their impacts for the communities.

JC-S: In the paper I analysed eight years of participatory monitoring data. This showed a thirty-fold increase in arapaima numbers in protected lakes compared with unprotected lakes. The overall population growth was over 400% in eight years. In some lakes there were originally only 20 arapaima remaining, and now there are 2000 or more!

The protected lakes act like high-interest saving accounts for the people. The arapaima are harvested once a year and generate around €8,000 per managed lake. This income is divided among participating families who are then investing together in improving local social infrastructure such schools and health posts. Moreover, the lakes provide a source of social security, with local people able to draw on other fish resources according to their needs. Another thing to mention is that arapaima management is addressing historic gender inequalities in the communities – women are included in the decision-making, income generation and in planning the use of natural resources.

PJ: In your view, what was the key to the success of this community management approach, and are there aspects that can be replicated elsewhere?

JC-S: I think that this Jura model has some special ingredients, including culturally important species, clear economic returns, strong local knowledge and a willingness to respect both locally generated and Federal rules. The combination of collectively agreed spatial zoning with no-take areas and a strong social organization has ensured compliance among users. Most people see the benefits – in terms of their livelihoods and life-quality – of respecting the rules and collectively managing the fishery.

The challenge of course is to replicate this model at a large-scale across the Amazon Basin. Now we have 30 areas adopting a similar model, and involving more 400 communities. The big challenges are ensuring fairness around the fisheries. By this I mean that middlemen don’t capture too much of the value. We also need to put in place the infrastructure to transport the fish – they are big, there are a lot of them, and it’s a long way to markets in Manaus and other Brazilian states!


The Giant South American Turtle can reach 90 cm in length and 75 kg in weight. Image: Priscilla Miorando

PJ: I understand you also researched community management of freshwater turtles. Tell us a little about that aspect?

JC-S: Alongside arapaima management the communities also started to protect freshwater turtles nesting on river beaches. The Giant South American Turtle (Podocnemis expansa) was also badly over-exploited but our research showed that community protection of beaches has induced a large-scale population recovery of this and other turtle species along a 1,500-km section of a major tributary of the Amazon River. We showed that egg collection happens in just 2% of nests on protected beaches, compared with 99% on unprotected beaches.

These activities have not yet generated economic returns. This is a problem because dissatisfaction is growing among community guards who get very little return for what can be dangerous work. Many are now on the brink of giving up and the long-term viability of this approach will require the development of revenue streams independent of the food support they receive from the government and NGO partners.

PJ: Your 2018 paper in Nature Sustainability talked about the ‘collateral benefits’ for other species of turtle protection. What were these?

JC-S: Beside the population recovery of the turtles we showed conservation benefits for a wide range of other species, including caimans, catfishes, river dolphin, green iguana, migratory birds and even invertebrates. The protected beaches become thronging and dynamic places of bio-abundance. A friend of mine, Karla Koehler, captured this difference in a nice sketch.

amazon protected beaches

Illustration of the ‘collatoral’ conservation benefits of protected beaches (left) versus no protection (right) in the Amazon Basin. Image: Karla Koehler

figura 3

A protected beach in the Amazon Basin. Image: Joao Vitor Campos-Silva

PJ: Traditionally Brazilian conservationists have adopted a protectionist approach to species conservation. Your research seems to show that sustainable use can work – do you think that attitudes are changing?

JC-S: Many older conservationists in Brazil believe that conservation and social outcomes are not possible in the same package. Sometimes I feel that phrases like ‘bottom-up’ and ‘community-based’ are assigned to initiatives that are in reality still top-down or externally managed. Many of these have failed and this may reinforce the perception that ecological recovery and community development are incompatible.

Community-based approaches are certainly not a panacea, but neither is it a naïve narrative. There are more than six million people in the Brazilian Amazon aspiring to basic improvements in their quality of life. By providing nature-based pathways to achieve this community-based resource management can counter the forces of deforestation and biodiversity loss. There is a younger generation of government officials who much more open to this way of thinking.


Cited papers:

Campos-Silva, J. V., & Peres, C. A. (2016). Community-based management induces rapid recovery of a high-value tropical freshwater fishery. Scientific Reports, 6, 34745.

Campos-Silva, J. V., Hawes, J. E., Andrade, P. C., & Peres, C. A. (2018). Unintended multispecies co-benefits of an Amazonian community-based conservation programme. Nature Sustainability, 1(11), 650.

Top 18 posts of 2018

January 3, 2019
meander path

Micro-meander formed on a cycle path following a storm. Many of this year’s top posts have addressed increasingly complex human-nature entanglements in aquatic ecosystems. Image: Evelyn Berg | Flickr Creative Commons

As we tiptoe into 2019, we’ve looked back over 2018 to collect 18 of our most popular posts on freshwater science, policy and conservation.

It’s been a great year for the Freshwater Blog, with a record numbers of visitors. Thanks, as always, for reading. You can keep up to date with our posts, and add your voice to the debate, through our Twitter, Facebook and LinkedIn pages.

Happy 2019!


‘Modest’ fine sediment and phosphate pollution in English rivers causes mortality of up to 80% of mayfly eggs (January)


Blue-winged Olive. Image: Francisco Welter-Schultes | Wikipedia Creative Commons

Increased levels of fine suspended sediment and phosphate in aquatic ecosystems can have significant negative impacts on the survival of mayfly eggs, according to a new study. Relatively modest levels of pollution can kill up to 80% of eggs, with potentially devastating effects on mayfly populations and wider aquatic food webs.

Writing in the journal Environmental Pollution, a team of researchers led by Nick Everall of the Aquascience Consultancy carried out experiments on the blue-winged olive, a species of mayfly found across Europe, whose populations have fallen in recent decades. (read more)


Messages from MARS (February)

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The final MARS project conference in Brussels. Image: Jörg Strackbein

The EU FP7 MARS Project“Managing multiple stress for multiple benefits in aquatic ecosystems”celebrated its final conference in Brussels last month.

The event concluded four years of in-depth research by MARS scientists on multi-stressor effects on European surface and ground waters, highlighting the implications for Water Framework Directive (WFD) related management. Among the array of fascinating results generated by the MARS project, four key messages were reported at the conference. (read more)


Managing multiple pressures from recreational activities on freshwater ecosystems (March)


Campsite beside a Swedish lake. Fuel and waste disposal can cause lake pollution. Image: Jörgen Brouwer

Rivers and lakes are popular places for people to relax, play and exercise, and recreational activities like boating, bathing and angling are all well-documented to have positive effects on human well-being. But can the enjoyment of such freshwater ‘ecosystem services’ cause pressures on aquatic ecosystems? And how best can recreational activities be managed to minimise the harm they might cause?

A review of available data on the topic recently published in the Environmental Reviews journal shows that environmental quality is closely liked to recreational activities in many freshwater ecosystems. The ecological health and diversity of a river or lake can be an attractive draw for visitors, potentially causing tensions between tourist ‘hotspots’ and areas of conservation importance. This means there is a pressing need for effective management strategies to minimise ecological damage from visitor use in many places. (read more)


Visualising multiple stressors on European river catchments: the MARS Scenario Analysis Tool (March)

sat mars laptop

Over the last four years, the MARS project has been investigating the interactions and impacts of multiple stressors on Europe’s aquatic ecosystems. This is a topic at the cutting edge of freshwater science research, and MARS scientists have sought to understand how the multiple pressures humans place on the environment – nutrient pollution, habitat alteration, climate change, water abstraction, and many more – act together to cause stress on the continent’s rivers and lakes. As a result, this work is important for environmental managers and policy makers seeking effective options to mitigate multiple stresses, and conserve or restore Europe’s freshwaters.

MARS has recently launched its Scenario Analysis Tool – an online, open-source mapping tool, which allows users to visualise and analyse multiple stressor conditions in European rivers. The tool can generate maps showing where different stressors occur, how many stressors co-occur, and their potential impacts on ecosystem status, at both the river basin and the continental scale. (read more)


The Water Framework Directive at 18: Future Directions and Emerging Challenges (May)


Image: Jim Liestman | Flickr Creative Commons

The Water Framework Directive (WFD) is the foundation of European Union water policy. Adopted in 2000, the WFD provides a policy framework for European member states to monitor, assess and manage their aquatic ecosystems. However, despite widespread improvements in the monitoring, conservation and restoration of rivers and lakes across Europe, the WFD has not yet achieved its primary objective: the good ecological status of all European freshwaters.

A formal EU ‘fitness check’ evaluation of the WFD is due in Autumn 2019. Ahead of this assessment, MARS researchers have published a policy brief providing recommendations for the future implementation and evaluation of European water policy. They identify four key areas to be addressed. (read more)


Trust your bank manager: riparian zones to protect and restore rivers (May)


Restored river section five years after restoration with riparian vegetation consisting of grasses, shrubs and trees. This riparian vegetation can effectively fulfill buffer functions and support riverine biodiversity. Photo: Christian K. Feld

Safeguarding the banks and margins of streams and rivers has a key role to play in ensuring river health. This is the major conclusion from a new international study recently published in Water Research.

The authors of the new study synthesised the findings of more than 100 river management studies, many of which addressed the effects of riparian restoration on riverine habitat and biological conditions. It is widely acknowledged that riparian plants provide food for aquatic organisms, and can mitigate water temperature increases under climate change. Riparian zones can also provide valuable ‘buffer zones’ for run-off from farming and urban areas, preventing pollutants from reaching the river channel. Yet such riparian effects are not to be taken for granted. (read more)


Reporting from MARS: multiple stressor science and management in European aquatic ecosystems (June)

Symbolique 2006

MARS has investigated how multiple stressors affect European rivers, lakes and groundwaters over the last four years. Image: Symbolique 2006

After four years of research on multiple stressor interactions and impacts in European aquatic ecosystems, the EU FP7 MARS project has published its final project report (pdf). 

The final MARS report gives a breakdown of project activities and results over the last four years. Significantly, it shows that the project has resulted in over 230 scientific publications, numerous policy briefs and factsheets, and a suite of online tools for water management. (read more)


New open-access book on key debates, approaches and directions in river management (July)


Clear waters and altered river bank at the Čunovo Dam on the Danube River in Slovakia. Image: Miroslav Petrasko | Flickr Creative Commons

Rivers across the world support rich biodiversity, yet are some of the most threatened global ecosystems, as a result of multiple pressures including pollution, water abstraction, habitat alteration and dam construction. As a result, river conservation and restoration are key topics for scientists, environmental managers and policy makers globally.

A new book Riverine Ecosystem Management: Science for Governing Towards a Sustainable Future provides a cutting-edge overview of contemporary approaches to river management. Available as a free PDF and ePub download, the book is edited by Stefan Schmutz and Jan Sendzimir from BOKU. (read more)


Less than half of European surface waters reach good ecological status, according to new EEA report (July)

river eea

The Neckar River at Ladenburg, Germany, which has significant hydromorphological alterations. Image: EEA

Less than half of Europe’s rivers, lakes and estuarine waters reach good ecological status, according to a recently published European Environment Agency report. Only 40% of European surface water bodies were found to be in a good ecological state, despite significant policy and management initiatives in recent decades to conserve and restore them. Roughly the same percentage (38%) of surface waters reach good chemical status, whilst nearly half (46%) do not.

The EEA report is based on data from EU-member states monitoring their surface and ground waters as part of the Water Framework Directive River Basin Management Plans (RBMPs). The report is the first overall assessment over European waters since 2012, and covers the second round of RBMP reporting. It contains data on over 130,000 water bodies across Europe, which have been monitored over the last six years. (read more)


Postcards from Heatwave Europe (August)


Low water levels on Lake Nisser in Norway. Image: Anne Lyche Solheim

Across the world, this summer’s weather has been characterised by extremes. The USA has experienced severe droughts and wildfires in the West, and flash flooding in the East, whilst an ‘unprecedented’ heatwave in Japan has been attributed as the cause of over 65 deaths. Most of Europe has experienced an extended period of high temperatures and minimal rainfall, causing wildfires to spread in both the Arctic Circle and Greece.

The high air and water temperatures, low rainfall and flashy storms and flooding experienced across Europe are all key pressures on the health and status of freshwater ecosystems. To gain a picture of how this summer’s weather is affecting European waters, we put a call out to our network of aquatic scientists across the continent, asking them to send in brief ‘postcards’ of their observations. (read more)


More Postcards from Heatwave Europe (August)


Dry lake bed at Thirlmere in the English Lake District. Image: Stephan Brzozowski

We recently published the first in a series of ‘Postcards from Heatwave Europe‘, in which aquatic scientists from across Europe offered their observations on how this summer’s extreme weather was affecting rivers and lakes in their local landscapes.

Today we have two more contributions to the series, from Sweden and the English Lake District. In Britain, at least, the weeks of hot, dry weather experienced this summer have recently been replaced by more unsettled conditions and regular thunderstorms. However, water levels in many lakes and rivers have yet to return to typical summer levels as a result of the prolonged dry spell. (read more)


The Alliance for Freshwater Life is launched (August)

7_Vjosa upstream meander_(c) LukasTB

The Vjosa river and floodplain in Albania: one of the last intact large river systems in Europe. Image: Lukas Thuile Bistarelli

A new global network aiming to halt and reverse the ongoing freshwater biodiversity loss crisis launched last Sunday at the World Water Week conference in Stockholm. The Alliance for Freshwater Life is an interdisciplinary network of scientists, conservation professionals, educators, policy experts, creative practitioners, and citizens working to improve the conservation and sustainable use of freshwater ecosystems and biodiversity. (read more)


Lake type affects how climate change causes algal blooms in European lakes (September)

2007_08_Loch Leven bloom3

Algal bloom on Loch Leven in Scotland. Image: Laurence Carvalho

Blooms of blue-green algae – otherwise known as cyanobacteria – are likely to increase in European lakes as a result of climate change, according to a new study. However, this trend is likely to vary depending on the individual characteristics of different lakes.

Writing in Global Change Biology, Dr. Jessica Richardson from the Centre for Ecology and Hydrology and colleagues used data from lakes across Europe to explore the sensitivities of different types of lakes to multiple environmental stressors associated with climate change and human activities. (read more)


Microplastics found in fifty percent of insects in South Wales rivers (October)


The River Usk in South Wales. Half of the aquatic insects sampled in the river were found to contain microplastics. Image: Photo Monkey | Flickr Creative Commons

A new open-access study by researchers from Cardiff University found that half of aquatic insects (or macroinvertebrates) sampled from three rivers in South Wales had ingested microplastics.

A research team led by Fred Windsor, a PhD researcher at Cardiff University School of Biosciences, sampled three different kinds of mayfly and caddis larvae at five sites on the Usk, Taff and Wye catchments. Each sampling site was located close to a waste water treatment plant, allowing macroinvertebrates to be sampled for microplastic ingestion both above and below water outflows from each plant. (read more)


Over a third of natural wetlands lost globally since 1970 (October)


Mubarak Al-Kabeer Reserve – a Ramsar site in Kuwait where shallow salt marshes and small lagoons provide a key habitat for migratory birds. Image: Abdualreda Alramzi | Ramsar

Over a third of natural wetlands have been lost globally since 1970, a rate of decline which is three times that of global forest loss over the same period. Wetlands are important habitats for wildlife, and provide a number of important ecosystem services to humans, including food security, flood protection and climate change mitigation. However, wetlands are being lost due to human development across the world, putting a quarter of the plants and animals which depend on them at risk of extinction.

These are some of the key findings of the new Global Wetland Outlook report, published by the Ramsar Convention on Wetlands, an international treaty on wetland conservation. The report – the first global wetland inventory of its kind – has been published to coincide with the 13th Ramsar Convention of Parties, held this week in the United Arab Emirates. (read more)


Global freshwater species populations decline by 83% since 1970 (November)

wwf freshwater lpi 2018

Image: WWF

Global freshwater species populations have dropped by 83% since 1970, according to a new report published by the World Wildlife Fund. The Living Planet Report 2018 assessed the populations of 880 representative freshwater species across the world between 1970-2014 to calculate the Living Planet Index.

The WWF report states that freshwaters – including lakes, rivers and wetlands – are the most threatened of all global habitats. Freshwater ecosystems provide habitat for over 100,000 known species of fishes, molluscs, reptiles, insects, plants and mammals, despite covering less than 1% of the Earth’s surface. (read more)


Managing multiple stressors in aquatic ecosystems: recommendations from the MARS Project (November)

mars recs

The MARS project has published a document titled “MARS Recommendations on how to best assess and mitigate impacts of multiple stressors in aquatic ecosystems”. This open-access pdf outlines a framework for how multiple stress conditions might be best mitigated in River Basin Management through the EU Water Framework Directive. (read more)


Emerging threats and persistent conservation challenges for freshwater biodiversity (December)


A stream illuminated by street lights. Light pollution is one of the emerging threats to freshwater ecosystems identified by the review. Image: Eric Fleming | Flickr Creative Commons

A new review of emerging threats to freshwater biodiversity, and the conservation challenges they pose, has been published. The review, led by Andrea Reid from the Fish Ecology and Conservation Physiology Laboratory at Carleton University, Canada, argues that the Anthropocene has brought numerous new and varied threats that disproportionately impact freshwater systems.

Writing in Biological Reviews, the authors state that new and effective conservation strategies are needed to address emerging threats, particularly because whilst freshwaters cover only 2.3% of the Earth’s surface, they support at least 9.5% of the Earth’s described animal species. (read more)


Thanks for reading, and a very happy 2019 to you! If you still have an appetite for more freshwater blogs, then you can also read our previous annual post round-ups for 2017 and 2016.

Emerging threats and persistent conservation challenges for freshwater biodiversity

December 21, 2018
abstract river

Numerous new threats to freshwater ecosystems have emerged in the last decade – many of which are poorly understood and difficult to manage. Image: Mark Strozier | Flickr Creative Commons

In 2006, freshwater scientist David Dudgeon and colleagues published a comprehensive review of the threats facing freshwater ecosystems and the urgent conservation actions required to tackle them. In the twelve years since their widely-cited review, the outlook for freshwater biodiversity has worsened, with freshwater species exhibiting steeper population declines (see our blog here) than marine and terrestrial species.

Dudgeon and colleagues identified five key threats to freshwater ecosystems: overexploitation; water pollution; flow modification; destruction and degradation of habitat; and invasion by exotic species. In the years since their paper, many of these threats have become more widespread and complex, whilst new and emerging threats have been identified, and the harmful effects of multiple stressors have been increasingly documented.

In other words, freshwater conservation now takes place in what is increasingly called the Anthropocene – a geological epoch characterised by human activity affecting environments and ecosystems at all scales.

light river

A stream illuminated by street lights. Light pollution is one of the emerging threats to freshwater ecosystems identified by the review. Image: Eric Flemin

In this context, a new review of emerging threats to freshwater biodiversity, and the conservation challenges they pose, has been published. The review, led by Andrea Reid from the Fish Ecology and Conservation Physiology Laboratory at Carleton University, Canada, argues that the Anthropocene has brought numerous new and varied threats that disproportionately impact freshwater systems. Writing in Biological Reviews, the authors state that new and effective conservation strategies are needed to address emerging threats, particularly because whilst freshwaters cover only 2.3% of the Earth’s surface, they support at least 9.5% of the Earth’s described animal species.

Reid says, “Since 1970, freshwater species have declined by a staggering 81% compared with <40% species declines both on land and in our oceans – why is freshwater biodiversity declining so severely and what are the biggest threats putting freshwater species in jeopardy? Freshwater ecosystems, like our lakes, rivers and wetlands, surround us and we rely on them for clean drinking water, hydropower, nutrition, recreation, navigation, scenic values, and much more. As these ecosystems become increasingly endangered, their ability to provide these services that underpin human wellbeing gets diminished.

Sadly, the current scale of freshwater declines is now so grave that we consider it an invisible tragedy – hidden beneath the water surface – that attracts far too little public, political, and even scientific interest. We are hoping to change this narrative through the publication of our article.”

emerging threats reid et al 2018

The twelve key emerging threats to freshwater ecosystems and their characteristics. Adapted from Reid et al 2018.

The authors identify twelve threats to global freshwater biodiversity which have either emerged or intensified since Dudgeon and colleagues’ 2006 review. Summarised in the graphic above, the paper shows the startling range of pressures on global freshwater ecosystems, which can potentially act in tandem in unpredictable ways as multiple stressor ‘cocktails’.

Co-author Prof Steve Ormerod, from Cardiff University School of Biosciences explains, “In this new review we wanted to update the story told by Dudgeon and colleagues – particularly with respect to problems affecting freshwater ecosystems that have emerged more prominently: climate change, invasions, diseases, harmful algal blooms, expanding hydropower, emerging contaminants, engineered nanomaterials, microplastics, light and noise, salinisation, declining calcium concentrations and cumulative stressors.

For each, we offer a specific overview, but come to the general view that an already dire prognosis for freshwater biodiversity is worsening while still being overlooked by many – perhaps even most – conservation biologists and ecologists. Mindful of the need to inspire action, however, we offer evidence where restorative and protective actions have benefited freshwater ecosystems: without hope, we cannot bring about the global efforts required to protect fresh waters as ecosystems that are fundamental our own ability to survive.”


Microplastic pollution is one of the twelve emerging threats identified in the study. Image: Florida Sea Grant | Flickr Creative Commons

The authors highlight five approaches to freshwater management and conservation which have the potential to address some of the emerging threats. First, environmental DNA (or eDNA) can be detected in water samples to detect the presence of rare and endangered species, or to track the spread of invasive species. Second, maintaining natural water allocations and variability (or environmental flows) in rivers and streams threatened by abstraction or flow alterations is an increasingly popular management approach to support resilient freshwater ecosystems.

Third, the negative impacts of aquaculture – parasites and invasive species, for example – can be minimised by supporting healthy freshwater ecosystems with fish stocks which can be sustainably harvested, the authors argue. Fourth, removing river obstacles such as dams and fishways can have significant ecological benefits to migratory species, although dam construction rates remain high in many areas. Fifth, the authors highlight the potential of managed relocation of species which will lose their climatic niche under future climate change; however, they note that this is a strategy with high levels of uncertainty over both appropriateness and effectiveness.

The authors highlight a number of freshwater conservation policy mechanisms and societal groups which might help mitigate emerging threats. These include regulatory instruments (e.g. The Water Framework Directive); fiscal incentives (e.g. agri-environment schemes); market opportunities (e.g. investments in ecosystem services with financial returns); and societal actions (e.g. campaigning for dam removal, participation in conservation activities, framing freshwaters as a political voting issue). Accordingly, the authors advocate for an increased global focus on freshwater threats and conservation, citing the recently formed Alliance for Freshwater Life, the 10 steps for responsible inland fisheries in the Rome Declaration and the post-2020 planning beyond the Aichi Biodiversity Targets as important steps in this direction.

However, the new review clearly highlights the significant multiple pressures – some known, some emerging – that are causing ongoing biodiversity losses in freshwater ecosystems across the world. Awareness of these threats and trends must spark positive conservation action. As the authors conclude, “We are merely at the beginning of the ‘great acceleration’ of the Anthropocene. Indeed, we may not even be able to imagine which environmental challenges we will face in the coming decades. In order to protect biodiversity and to support human well-being, we need to manage fresh waters collectively across sectors and as hybrid systems – managing freshwater ecosystems as both a pivotal resource for humans as well as highly valuable ecosystems.”

Reid, A. J., Carlson, A. K., Creed, I. F., Eliason, E. J., Gell, P. A., Johnson, P. T., Kidd, K. A., MacCormack, T. J., Olden, J. D., Ormerod, S. J., Smol, J. P., Taylor, W. W., Tockner, K. , Vermaire, J. C., Dudgeon, D. and Cooke, S. J. (2018), Emerging threats and persistent conservation challenges for freshwater biodiversity. Biol Rev. doi:10.1111/brv.12480

The DESSIN software tool for ecosystem service assessment in urban freshwaters

December 14, 2018

dessin headerA guest post from the DESSIN project

A new software tool for Ecosystem Service (ESS) assessments is now available. The DESSIN ESS software tool helps environmental practitioners and decision-makers identify, measure, and value ESS, particularly in urban freshwater environments.

The DESSIN ESS software tool was developed by the EU FP7 DESSIN project and is now supported by DHI, one of the project partners. The main objective of DESSIN was to demonstrate innovative solutions for water management, along with a methodology for measuring and valuing ESS.

DESSIN ran from 2014 to 2017, and was based on the assumption that a better understanding of ESS values can help us assess the potential benefits of innovative technologies that reduce water scarcity and improve water quality. Measuring changes to ESS helps us translate impacts on ecosystems to impacts on human welfare, broadening the scope of cost-benefit analysis, and stimulating the update of innovative technologies to help strengthen water management.

The DESSIN methodology for measuring ESS was described in the DESSIN ESS assessment framework and has been formalised into a reproducible methodology through the DESSIN software tool. The software tool is now available for free as part of DHI’s MIKE Workbench software and can be downloaded here.

Dr. Sebastian Birk, director of the MARS project, says, “The DESSIN ESS assessment framework is a state-of-the-art approach for assessment of ecosystem services in urban freshwater settings. The DESSIN software tool makes it easy to apply the framework in a way that is consistent and reproducible.”

The DESSIN ESS software tool facilitates the rapid and comprehensive assessment of ESS services and corresponding economic values in a study area. The tool is geared towards the assessment of available technical and management measures, the potential effectiveness of which can be compared to a ‘no-action’ baseline.


The DPSIR framework for ecological management.

Ecosystem services are services provided by nature to humans, and the DESSIN ESS assessment framework assumes that the level of ecosystem service provision is a function of the state of the ecosystem. Therefore, improvements to the state of the ecosystem are related to better provision of services. The framework begins with a comprehensive assessment of the underlying ecosystem state, which is then related to the provision of ESS. The framework is based on the DPSIR framework (Drivers, Pressures, States, Impacts, Responses), which is widely used in environmental assessments in Europe.

The DESSIN ESS assessment framework links ecosystem state to ESS provision, use, and value through a complex chain of relationships that are captured in a database. The DESSIN software tool provides access to this database in a user-friendly way that makes it easy to apply the framework and keep track of these relationships. It consists of a comprehensive indicator database, including ecosystem state, provision, and use indicators, as well as database of economic valuation methods and studies.

DESSIN locations

Map of DESSIN case studies.

During the DESSIN project, the software tool was applied at five demonstration locations in Europe, to estimate the impact of innovative technologies on ecosystem services, along with associated impacts on human welfare:

In addition, the DESSIN software tool was tested during development on a case study in Aarhus, Denmark, where it was used to evaluate an urban river restoration project.

Niels Riegels from the development team at DHI says, “The DESSIN software tool provides a straightforward way to apply the DESSIN ESS assessment framework. The tool organises information in an accessible database and facilitates easy linkages to any data and models used to support the assessment.”

For more information about the DESSIN software tool, please contact Niels Riegels at

More information:

Download the DESSIN software tool

Read about the DESSIN ESS assessment framework

Visit the DESSIN project website

The AQUACROSS Assessment Framework: supporting effective floodplain restoration in the Danube Basin

November 30, 2018

A fallen tree on the bank of the Danube River. Image: Andrea Funk | AQUACROSS

The Danube is one of the great rivers of Europe, with a catchment of 800,000km2 which is home to more than 80 million people from 19 countries. The diversity of human life in the Danube basin is mirrored by its biogeographic diversity, moving from high Alpine mountain streams to looping lowland meanders and floodplains as the river flows 2,800km eastwards to its estuary in the Black Sea. As a result, the Danube basin provides habitat for a rich range of biodiversity, notably for wetland birds, freshwater molluscs and fish, including five species of endangered sturgeon and the Danube salmon, or huchen.

Sadly, the numerous human activities in the Danube basin have placed significant pressures on the ecological health and status of the river. Throughout the basin, the construction of hydropower plants, expansion of agriculture, and large-scale river regulation measures for navigation and flood protection are causing extensive hydromorphological pressures on the river ecosystem. As a result, in many parts of the Danube basin, natural floodplain areas have been disconnected from the river channel, or lost altogether, causing significant ongoing losses of habitat and biodiversity.

Multiple pressures, multiple policies

In response to these pressures, schemes to restore river-floodplain systems have been developed throughout the Danube basin. These restoration schemes relate to the implementation of a number of wider policy instruments, including the EU Biodiversity Strategy to 2020, the EU Strategy of the Danube Region, the Danube River Basin Management Plan for the Water Framework Directive, the EU Floods Directive, and the Birds Directive and Habitats Directive.

The diversity of these policies reflects the range of potential benefits to biodiversity, ecological status, natural flood protection and climate change mitigation that river-floodplain restoration can foster. However, the complexity of environmental problems and cross-border legislation in the Danube basin, coupled with a lack of adequate ecological data on the river ecosystem has significantly hampered floodplain restoration efforts. As a result, only a few countries in the Danube region have already implemented (or even planned) restoration activities, which are due by 2021.

Danube River Basin District Map

The Danube is the ‘most multinational river in the world’ according to the WWF. Image: ICPDR

The AQUACROSS Assessment Framework

To try to support floodplain restoration efforts across the Danube basin, the EU AQUACROSS project undertook research on the river using their Assessment Framework. The framework addresses three main factors to identify suitable sites for restoration and conservation. First, the remaining ‘multi-functionality’ of the system, in other words, the health and diversity of the ecosystem, even when highly pressured by human activities. Second, the ‘reversibility’ of the degraded ecosystem, or the potential to restore a multi-functional ecosystem. Third, the availability of remaining semi-natural land versus agricultural land in riparian areas around the river channel.

Essentially, the AQUACROSS Assessment Framework allows for the identification of sites for floodplain restoration where habitat, biodiversity and ecosystem service provision can be improved concurrently. The Framework is based on the joint application of Bayesian Biodiversity models and Ecosystem Service Models (ARIES). This integrated approach, which brings together multiple objectives for promoting biodiversity, ecosystem services and socio-economic benefits together, is designed to facilitate the implementation of ecosystem-based management in the Danube basin.

Assessing ‘baseline’ and ecosystem-based management approaches

When the AQUACROSS Assessment Framework was applied in the Danube basin, indicators for biodiversity, ecosystem services (such as flood retention, crop pollination and recreation potential), pressures (such as hydromorphological alteration) and drivers (such as land-use and hydropower) were modelled for two future scenarios: baseline (i.e. ‘business as usual’) and ecosystem-based management. At all stages, this process was supported by engagement with stakeholders across the basin.

The AQUACROSS results suggest that a ecosystem-based management approach can be more cost-effective in restoring floodplain biodiversity and ecosystem services than the baseline approach. They indicate that the multiple priorities considered by the ecosystem-based management create the opportunity to pursue different policy objectives simultaneously, and in so doing offer the potential to foster cross-border coordination of policy implementation and data sharing for floodplain restoration.

The AQUACROSS team highlight that the ecosystem-based management approach can thus help support the selection of restoration sites, whether under Habitats Directive protected areas, Water Framework River Basin Management Plans, or Floods Directive Flood Management Plans. In short, the AQUACROSS Assessment Framework provides an invaluable tool for helping restoring the health and status of the Danube basin under multiple human pressures.


A connected floodplain sidearm channel of the Danube. Image: Andrea Funk | AQUACROSS

Reflections on the AQUACROSS Danube project

Andrea Funk, a lead AQUACROSS scientist on the Danube case study says, “Linking available multi-disciplinary data within a new model framework allows us to systematically prioritise floodplain segments along the Danube for conservation and restoration, partially confirming already designated restoration sites, as well as identifying others in areas where no sites are yet designated.”

Thomas Hein, a lead AQUACROSS scientist on the Danube case study says, “The cooperation of different leading scientific institutions and key stakeholders in the Danube River Basin allowed to define highly relevant research objectives and provided new results on a quantitative modelling approach to identify the biodiversity and ecosystem service potential and thus, the potential for floodplain restoration.”

Ursula Scheiblechner, Project Manager with Danube river management stakeholder organisation viadonau says, “The AQUACROSS Danube case study gives us a very large-scale view from source to the mouth of the river Danube. viadonau has a decades-long tradition of realizing ecological projects at the Danube in Austria. During the planning and construction phase of a project we have to look very close at the particular project area and several effects of the measures. It was interesting for us, that the AQUACROSS Danube case study with its large- scale analysis comes to similar conclusions in determining relevant restoration sites at the Danube as we do.”


Find out more:


AQUACROSS Danube River Basin Case Study Executive Summary

AQUACROSS Danube River Basin Case Study Full Report

Managing multiple stressors in aquatic ecosystems: recommendations from the MARS Project

November 22, 2018

mars recsManaging and restoring aquatic ecosystems affected by multiple stressors is a key contemporary challenge for environmental scientists, managers and policy makers. As we’ve documented on this blog over the last few years, many European water bodies are subject to multiple human pressures such as pollution, climate change, hydrological and morphological alterations.

Such pressures can cause stress to the health and status of aquatic ecosystems. A stressor can represent either the immediate cause of decreasing ecological status (e.g. oxygen depletion caused by high water temperatures), or be part of a chain of factors which cause ecological degradation. In other words, stressors are how human pressures directly affect ecosystems.

The stressor concept allows us to outline both how human pressures can stress ecosystems in numerous ways, and to be specific about why a water body might not reach good ecological status as a result of the presence of different stressors.

mars pressure stressor

Stressors are how human pressures directly affect ecosystems. Image: MARS

Between 2014 and 2018, the EU FP7 MARS project investigated the interactions and impacts of multiple aquatic stressors, resulting in more than 200 scientific publications and an extensive range of online tools for water management.

This week, the project has published a document titled “MARS Recommendations on how to best assess and mitigate impacts of multiple stressors in aquatic ecosystems”. This open-access pdf outlines a framework for how multiple stress conditions might be best mitigated in River Basin Management through the EU Water Framework Directive.

The MARS framework supports environmental decision-making by providing tools and guidance for water managers to identify dominating and interacting stressors. Whilst multi-stressor situations vary between ecosystems, three broad guidelines for their management are identified.

First, where there are dominant individual stressors (e.g. water pollution), these should be the main priority for mitigation. Second, where stressor interactions are antagonistic (i.e. they ‘cancel each other out’ to some extent – e.g. nutrient and water flow increases), then the non-antagonistic stressors present should be targeted for mitigation. Finally, where stressor interactions are synergistic (i.e. they have effects ‘more than the sum of their parts’ – e.g. nutrient and temperature increases), then all present stressors should be targeted simultaneously, as far as possible.

MARS Qs for stressor management

Key questions for tackling multi-stressor conditions in River Basin Management using MARS outputs. Image: MARS

MARS research has demonstrated that there are some general patterns between stressor pairs, particularly in waterbody type specific interactions between nutrient and temperature fluctuations in lakes. However, the new recommendations document emphasises that assessment of stressor interactions and impacts, and planning measures for their mitigation, requires case-specific assessment. In other words, whilst there are some broad guidelines for managers to follow, the stressor conditions in individual waterbodies are key in guiding specific management approaches.

MARS provides a number of open-access online tools to help water managers diagnose and mitigate aquatic stressor conditions. These allow users to explore large spatial datasets on European stressor distributions and effects, and to examine cause-effect relationships between pressures, stressors, ecological status and management measures.

Other tools allow users to select the most suitable computer models to support their River Basin Management, to diagnose the causes of ecological deterioration based on biological metrics, and to visualise current and future multiple-stress conditions and ecological status in European rivers and lakes. Heat maps provide an innovative visual means of identifying how two stressors interact, and how mitigation efforts might shift an ecosystem towards good ecological status.

mars heat maps

MARS ‘Heat Maps’ of stressor pairs showing the expected gradient between ‘good’ and ‘moderate’ ecological status achieved by reducing stressor levels in additive (left) and synergistic (right) conditions. Image: MARS

The document also provides examples from seven MARS case studies to show how theory has been applied in practice, and to highlight key questions for River Basin Management.

Broadly, the recommendations from the MARS project show how the large datasets about European aquatic ecosystems (much of which is generated through Water Framework Directive monitoring) can be used to improve River Basin Management Planning. More specifically, it shows how the emerging environmental issue of multiple stressors – arguably a key signal of the Anthropocene in freshwaters – can be addressed by agile and responsive science and management.

MARS has significantly raised the profile of multiple stressor issues in scientific, policy and public realms, and provided an extensive range of information, tools and resources for users to implement in environmental management and restoration. Now is the time for this information to be applied and extended. With the publication of the new MARS recommendations document, there are reasons to be optimistic over the prospects for the health and status of European aquatic ecosystems in the future.

Read MARS Recommendations on how to best assess and mitigate impacts of multiple stressors in aquatic ecosystems

MARS EU FP7 Project

Freshwater Information Platform


Global freshwater species populations decline by 83% since 1970

November 7, 2018

The Zambezi River in Africa: home to diverse populations of wildlife, but increasingly pressured by water pollution and dam construction. Image: Ninara | Flickr Creative Commons

Global freshwater species populations have dropped by 83% since 1970, according to a new report published by the World Wildlife Fund. The Living Planet Report 2018 assessed the populations of 880 representative freshwater species across the world between 1970-2014 to calculate the Living Planet Index.

The WWF report states that freshwaters – including lakes, rivers and wetlands – are the most threatened of all global habitats. Freshwater ecosystems provide habitat for over 100,000 known species of fishes, molluscs, reptiles, insects, plants and mammals, despite covering less than 1% of the Earth’s surface.

Overall, freshwater habitats are home to more than 10% of known animals and about one-third of all known vertebrate species. However, as the new figures show, freshwaters are experiencing significant biodiversity loss. The report identifies multiple pressures driving biodiversity loss including habitat modification, fragmentation and destruction; invasive species; overfishing; pollution; disease; and climate change.

wwf freshwater lpi 2018

Image: WWF

The report highlights the importance of ‘connected and free-flowing’ rivers in supporting healthy freshwater ecosystems, and the human populations which rely on them. When reservoir or hydropower dams are built, rivers straightened and their banks reinforced, or floodplains built on, the natural processes that take place throughout a river system are often damaged. Such processes often include fish migration, the dynamics, temperature and volume of water flows, seasonal flooding (and floodplain fertilisation) and sediment movement.

A recent scientific paper estimates that around half of global rivers are significantly impacted by flow regulation and/or fragmentation. As the report highlights, this means more than a quarter of the sediment which was naturally transported by global rivers to the ocean each year is now being trapped behind dam walls in reservoirs. Assuming the completion of all dams planned and under construction, it is predicted that the global percentage of rivers which are fragmented or regulated would nearly double to 93%, largely due to major dam construction in the Amazon Basin.

Increasing demands on water have also significantly reduced the global number of permanent rivers and lakes in recent decades, the report highlights. Based on over three million satellite images analysed using the Water Explorer, it is estimated that more than 90,000km2 of previously permanent freshwaters have been lost or become intermittent. In other words, rivers and lakes which previously existed all year round are now either gone or dry for periods of each year, as a result of water abstraction, dam construction and flow diversions. Over 70% of this loss of surface waters is concentrated in just five countries in Central and Western Asia.

rio grande

Dry river channel on the Rio Grande, USA where water abstraction and dam construction have caused sections of the river to temporarily dry out. Image: JN Stuart | Flickr Creative Commons

In short, the regulation and disconnection of water flows through river catchments can throw complex and dynamic freshwater systems off kilter, and significantly alter the habitats they provide. This has contributed not only to the significant declines in freshwater biodiversity, but often also has negative effects on human communities who rely on freshwaters for food, water, and fertile agricultural land.

More widely, across all terrestrial, freshwater and oceanic ecosystems, the Living Planet Index calculates that global populations of mammals, birds, fish, reptiles, and amphibians have declined, on average, by 60% between 1970 and 2014, the most recent year with available data. This figure is based on data on 16,704 populations of 4,005 vertebrate species globally.

“This report sounds a warning shot across our bow,” says Carter Roberts, president and CEO of WWF-US. “Natural systems essential to our survival—forests, oceans, and rivers—remain in decline. Wildlife around the world continue to dwindle. It reminds us we need to change course. It’s time to balance our consumption with the needs of nature, and to protect the only planet that is our home.”

“In the next years, we need to urgently transition to a net carbon-neutral society and halt and reverse nature loss through green finance and shifting to clean energy and environmentally friendly food production,” says Marco Lambertini, Director General of WWF International. “In addition, we must preserve and restore enough land and ocean in a natural state to sustain all life.

But we have two main problems. First, and perhaps the greatest, is the cultural challenge. For too long we have taken nature for granted, and this needs to stop. The second is economic. We can no longer ignore the impact of current unsustainable production models and wasteful lifestyles. These must be accounted for and addressed.”


The Mekong giant catfish, a critically endangered species native to the Mekong basin in South-East Asia. Image: Lynn Chan | Flickr Creative Commons

The report develops short-term and long-term imperatives for policy and management which can ‘bend the curve of biodiversity loss’ (a phrase from a related recent Nature Sustainability paper). First, it highlights a ‘window of opportunity’ between now and 2020 to strengthen environmental policy as new goals and targets are currently being set for the Convention on Biological Diversity (CBD).

Secondly, it develops a ‘roadmap for 2020 to 2050’ to halt biodiversity loss, calling for the ambitious goals of the CBD – “By 2050, biodiversity is valued, conserved, restored and wisely used, maintaining ecosystem services, sustaining a healthy planet and delivering benefits essential for all people” – to continue to provide the basis of global environmental policy and management. This goal can be supported by the ongoing development of more effective biodiversity indicators, and scenario models which predict biodiversity trends in the future, the report argues.

Overall, the message is one that ‘business as usual’ approaches to managing biodiversity loss are not enough, and that the debate needs to be reframed from one in which ‘nature is nice to have’ to one in which ‘nature is a need to have’. This is a process in which the political and social relevance of nature is radically escalated, in order to galvanise cohesive movements which drive positive environmental change. As the report concludes, “We are the first generation that has a clear picture of the value of nature and the enormous impact we have on it. We may also be the last that can act to reverse this trend.”

Read the WWF Living Planet Report 2018

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