
Last week, the MERLIN project held an all-partner meeting to discuss the progress made in the first six months of collaborative work.
MERLIN is a major environmental project which aims to mainstream freshwater restoration in Europe. Funded by the European Commission’s Horizon 2020 scheme, MERLIN will invest €10 million into restoring freshwater ecosystems across Europe in coming years.
Over 100 participants attended the virtual meeting over two days last week to hear talks from MERLIN Work Package leaders on project progress, and to take part in discussions on future plans.
In his introduction to the meeting, project leader Prof. Daniel Hering outlined some of the important steps already made in MERLIN. Prof. Hering described how discussions over monitoring the impact of freshwater restoration case studies have resulted in a MERLIN Monitoring Handbook. This document provides indicators for monitoring the outcomes of freshwater restoration, and how it can contribute towards EU Green Deal goals. The Handbook will be made available later this year to help support restoration practitioners.

“Six months into the project, the meeting provided clarity on our approaches to achieving MERLIN’s ambitious objectives”, says MERLIN co-ordinator Dr. Sebastian Birk. “One key focus of the meeting was to exchange ideas on the monitoring plans that will be implemented in the 17 restoration cases.
“Here, it became increasingly clear how the different targets of the Green Deal are addressed: How can we best measure the re-wetting of peatlands? How do we guarantee the inclusion of interested citizens? Over the coming months, the MERLIN case studies will set up their monitoring of restoration impacts”, Dr. Birk explains.
Communication and dissemination of the project’s goals was another key theme of the first six months. Prof. Hering highlighted the success of the MERLIN webinars, which offer free monthly discussions of important topics around restoration science, management and policy.
Project partners have also produced a leaflet outlining how MERLIN aims to support freshwater restoration as a means of mainstreaming nature-based solutions for more sustainable European societies. You can read it here in English, Spanish, Basque, Finnish, Hungarian, Polish and Portuguese.

Highlighting the many benefits fostered by freshwater restoration is an important step in encouraging collaborations with multiple water users and stakeholders. Accordingly, MERLIN partners have held sector-specific round table meetings around issues such as drinking water supply and navigation.
“MERLIN has started dialogues with the insurance business and the navigation sector”, says Dr. Birk. “The first insights about co-benefits for nature and economy were shared during the project meeting.”
Work within MERLIN continues apace: you can keep up to date on the project website and social media.
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This article is supported by the MERLIN project.

In recent years, scientists have increasingly shown how freshwater ecosystems are impacted by a range of human-caused stresses, which can significantly affect their health and biodiversity.
As a result, research into the interactions and impacts of so-called ‘multiple stressors’ has blossomed, both in Europe and globally. Now, a newly-published paper shows that the ecological degradation of Iberian freshwaters is largely caused by the impacts of two or more combined stressors.
The study authors reviewed 61 scientific articles exploring the effects of different stressor combinations on freshwater ecosystems and organisms from the Iberian Peninsula. The research team, led by Dr. Cayetano Gutiérrez-Cánovas (Doñana Biological Station-CSIC, Spain) and Dr. Susana Pallarés (University of Seville, Spain), collaborated with scientists from 11 Iberian and international institutions.
Writing in Limnetica, the authors found that the key stressors in Iberian Peninsula freshwaters are nutrient enrichment, toxic substances such as pesticides, salinity, ultraviolet radiation, flow reduction and warming.
The team also observed a high variability of stressor effects across different types of organisms, freshwater ecosystems and experimental approaches. For example, manipulative studies tended to find a higher prevalence of interactive effects for some organism groups, compared with observational studies. Such interactions arise from complex situations where the combined effect of different stressors is not equal to the sum of their individual effects.

“Our work highlights the need to consider the multiple impacts driving freshwater degradation in management and restoration actions,” says Cayetano Gutiérrez-Cánovas. “This work in the Iberian Peninsula demonstrates that the traditional single stressor perspective would be effective only in a minority of cases. And, more importantly, this situation could be applicable to other European areas, where 39% of EU water bodies are affected by two or more anthropogenic pressures,” continues Susana Pallarés.
The Iberian Peninsula is one of the most important global biodiversity hotspots, and supports a rich variety of climates and freshwater habitats. However, the ongoing climatic aridification in the area, combined with growing water demands for food production and urban areas, exerts increasing pressure on Iberian aquatic ecosystems.
To tackle this multiple stressor scenario, the study authors suggest the need to implement mitigation actions that consider climate change along with other impacts, including nutrient enrichment, hydromorphological alteration and invasive species.
The scientific team also identified research gaps to be addressed in future investigations. Among them, the authors suggest increasing research efforts on some aquatic ecosystems – such as lakes, lagoons and wetlands – and organisms that have not been studied in sufficient detail, such as algae and aquatic vegetation. They also propose more observational studies to address multiple stressor effects on natural freshwaters.
In addition, the authors suggest that the ongoing multiple stressor research agenda should include a more detailed investigation on the consequences of biodiversity loss for the ecosystem functioning and services provided by aquatic environments in a global change context, where several impacts often act simultaneously.
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A new open letter from the World Wide Fund For Nature (WWF) calls for freshwater biodiversity to be better recognised in international environmental policy. Released this week, the open letter asks policy makers at the upcoming UN Biodiversity Conference in Kunming, China – held between 25 April – 8 May 2022 – to strengthen protections for global freshwaters.
“The Convention on Biological Diversity (CBD) Open Ended Working Group is currently underway in Geneva to discuss a new global framework for nature,” says Eva Hernández Herrero, WWF Living European Rivers Initiative Lead. “Despite the evidence of the steep decrease of freshwater biodiversity – which is 2–3 times worse than that of land or marine habitats – freshwater habitats keep on being obviated in the text proposals and relegated to a footnote.
“It is proven that conservation strategies focused on land don’t render the results rivers and wetlands need. Conserving a wetland does not only need land protection, for example, but also appropriate water management. And it is clear that freshwater habitats matter as much to people and climate as they do to nature, and they can help in building a bridge for the health of the planet.
“With this Open Letter we want to ask for a simple but significant change in all the texts of the upcoming Kunming agreement: that we start talking about land, freshwater and oceans. Let’s not allow the source of life to vanish,” Hernández Herrero states.
You can read the open letter below, and add your name to it on the WWF website.
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Failure to elevate freshwater to the same priority as ‘land and ocean’ would be a fatal flaw in the new global framework for nature
We (the undersigned) are growing increasingly concerned about the fate of freshwater biodiversity in the new global framework for nature under the Convention on Biological Diversity (CBD). Despite evidence showing that freshwater habitats are experiencing 2-3 times the rate of biodiversity loss of terrestrial and marine habitats, current discussions and the draft CBD text still focus primarily on ‘land and ocean’ and relegate freshwater – once again – to the status of a subset of terrestrial ecosystems.
We fear that unless freshwater is elevated to the same status as ‘land and ocean’, the new CBD framework to be agreed in Kunming will suffer from the same structural weakness that undermined the Aichi agreement. By treating freshwater biodiversity as second class biodiversity, Aichi contributed to the ongoing marginalization – and dramatic loss – of freshwater species and ecosystems, which is having such a devastating impact on people, nature and climate.
This is despite the overwhelmingly large role that fresh waters play in supporting life on earth. Fresh waters cover less than 1% of the earth’s surface, yet rivers, lakes and freshwater wetlands are home to 10% of all species, including more than half of all fish species. But freshwater species populations have declined by 84% on average since 1970 and one third are now threatened with extinction.
If we are to change the status quo and reverse the downward trajectory for freshwater biodiversity – and for biodiversity in general – fresh waters must be a conservation priority. The new global framework for nature must elevate freshwater habitats as a unique ‘domain’ that merits co-equal status with ‘land and ocean’. It is time to ensure that freshwater biodiversity is no longer invisible and overlooked, but rather explicitly recognized, valued and protected.
1. Imagine if Aichi had focussed solely on ‘rivers and reefs’, what would have been the impact on the world’s rainforests?
Slowing deforestation has proved incredibly difficult despite tropical forests being a central focus of global science, conservation and environmental agreements. Now imagine if Aichi had not talked about ‘land’ at all but had specified ‘rivers and reefs’ with rainforests merely as an asterisked footnote (* rainforests are under rivers), governments would have had even less incentive to act to rein in deforestation or to save forest species. Instead, they would have devoted their time to rivers and reefs, sacrificing terrestrial biodiversity as they focused their efforts on the freshwater and marine biomes.
The reality is that the world’s efforts to halt and then reverse the loss of biodiversity have been undermined by a similarly blinkered approach that prioritizes only ‘land and sea’. This approach has been (inadvertently) promoted by scientists and conservationists – two groups that are overwhelmingly dominated by experts in terrestrial biodiversity – and who have incorrectly assumed that safeguarding land areas automatically conserves the rivers that flow through them or the lakes that lie within them. Unsurprisingly, this scientific-conservationist consensus has been endorsed by governments and global agreements – so that it is now second nature for people to refer to ‘land and sea’ as if there are no rivers connecting the two. But the world is interconnected. We cannot halt the loss of nature, let alone restore it, unless we prioritize all three biomes – land, freshwater and sea.
Leaving ‘freshwater’ out of the main text and relegating it to a footnote – as some parties have suggested – because it will simplify the final framework is incredibly shortsighted. It omits explicit consideration of the distinct character and status of freshwater habitats. The new global framework for nature must give them equal status. Ensuring that the agreement talks about “land, freshwater, and sea” is a simple, straightforward and significant initial step to elevate rivers, lakes, and freshwater wetlands to a status equal to terrestrial and marine domains.
2. Stop lumping rivers, lake and freshwater wetlands in with ‘protected land areas’, it results in poor outcomes for biodiversity
The new global framework for nature can finally end the tried-and-failed approach of tethering progress on the protection of freshwater ecosystems, particularly rivers, to progress on land. Freshwater habitats are highly dynamic, with hydrological connectivity (i.e., flow, sediments, and nutrients) being critical to their functioning. They have distinctive management needs that recognise and protect the crucial roles of flow, connectivity, and related ecological processes for sustaining freshwater species and habitats. Failure to recognise these distinctive needs has led to the ongoing underrepresentation of freshwater aquatic habitats – especially large, biodiverse rivers – in reserve networks and frequent failures to protect freshwater biodiversity.
Recent evidence showed that prioritizations based solely on terrestrial needs yielded just 22% of the freshwater biodiversity benefits yielded by freshwater conservation actions. The Kunming agreement can start to rectify this – transforming the global approach to freshwater conservation so that it benefits people, freshwater biodiversity and all the world’s interconnected ecosystems.

3. Protecting more of the planet is only part of the picture: reversing the loss of freshwater biodiversity requires a transformation in the way we manage the world’s working waters
Expanding protected areas and other effective area-based conservation measures is a key part of the solution to nature loss. But it is only part of the solution. The critical target for freshwater biodiversity is actually not area based: it is the percentage of working rivers and lakes that are sustainably managed. Working rivers and lakes are essential to societies and economies for drinking water, irrigation, energy, fisheries, transport and waste. We cannot ‘protect’ them but we can ‘use them wisely’ – as the Ramsar Convention on Wetlands states – for the benefit of people and freshwater biodiversity. The new global framework for nature must enshrine measures to ‘wisely use’ the world’s working waters – from restoring connectivity to implementing science-based environmental flows and the other pillars of the Sustainable Freshwater Transition in the 5th Global Biodiversity Outlook.
4. Freshwater Matters… for people, nature and climate
Prioritizing freshwater in the new global framework is not just essential for national and global efforts to tackle the nature crisis, but also for national and global efforts to address the climate crisis and achieve the Sustainable Development Goals.
As the CBD Executive Secretary, Elizabeth Maruma Mrema, made crystal clear in a powerful video produced by UN Water:
“The fifth Global Biodiversity Outlook outlines a sustainable freshwater transition to reverse biodiversity loss and its impact on freshwater ecosystems, species, and services. This transition recognizes the importance of biodiversity in maintaining the multiple roles of freshwater ecosystems to support human societies and natural processes, including linkages with terrestrial, coastal, and marine environments.
The post-2020 global biodiversity framework can help bend the curve of biodiversity loss by ensuring that freshwater ecosystems are protected, conserved, and wisely used; not only for our generation, but for generations to come.”
Conclusion – A stool with only two legs will never stand up
The new global framework for nature will fail to reverse the loss of nature if it focuses on ‘land and ocean’ – it would be like designing a stool with only two legs. The speed at which freshwater habitats, flora, and fauna globally are being degraded and destroyed necessitates concerted and widespread remedial action. This will only happen if the new CBD framework – and consequent national policies and action plans as well as financial investments and instruments – elevates the biodiversity of rivers, lakes, and freshwater wetlands to the same priority as forests and oceans.
We call on governments to ensure that the new global framework works for people and nature by prioritizing measures to safeguard freshwater biodiversity:
- Enshrine ‘land, freshwater and sea’ throughout the post-2020 Global Biodiversity Framework, replacing all blinkered references to ‘land and sea’:
- Incorporate a clear call to protect and restore connectivity, which is central to the health of rivers and other freshwater ecosystems and biodiversity
- Incorporate targets linked to the pillars of the Sustainable Freshwater Transition as outlined in the CBD’s 5th Global Biodiversity Outlook:
- Protect and restore critical habitats;
- Integrate environmental flows into water management policy and practice;
- Combat pollution and improve water quality;
- Prevent overexploitation of freshwater species and resources; and
- Prevent and control alien invasive species.
Add your name to the open letter on the WWF website.
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This article is supported by the MERLIN project.

Ecological restoration is a key part of modern environmental management: often seeking not only to bring degraded ecosystems back to life, but also to help create landscapes that are resilient to future climatic changes. As a result, restoration projects are being implemented all over the world, and the United Nations have designated this the ‘Decade on Ecosystem Restoration’.
Restoration is rarely a straightforward process: its ecological trajectories can be slow and uncertain, and often require the collaboration of numerous different people and organisations across a landscape. As a result, there is real value in finding out about how successful restoration projects have been planned and carried out.
Wild Haweswater is one such project. Located in the Lake District National Park in north-west England, the restoration of the Haweswater valley has been carried out alongside traditional hill farming, as a means of benefiting biodiversity, water and local communities. We spoke to Lee Schofield, RSPB Site Manager at Haweswater, to find out more.
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The Freshwater Blog: What is the overall aim of the Wild Haweswater project? Why is it important to undertake restoration work here, and how would you like the landscape to take shape in the future?
Lee Schofield: At Haweswater, the RSPB work in partnership with landowner United Utilities to manage about a third Haweswater Reservoir’s 10,000ha catchment, in order to benefit water, wildlife and people. The RSPB are tenants of two hill farms, Naddle and Swindale, on the eastern side of the reservoir, which extend to around 750ha. Associated with the farms are common grazing rights across a further 2,000ha. This land is a mosaic of woodlands, scrub, bogs, heaths, grassland, crags, meadows, tarns and rivers. Our focus is on restoring these habitats, many of which have been negatively impacted by grazing, drainage and other human activity over the course of centuries.
Although some of what we are doing could be described as rewilding, we also have a farming operation, involving sheep and cattle. Our aim is to try to demonstrate that sustainable farming, in keeping with the Lake District’s farming traditions, can be integrated with landscape scale ecological restoration. We have developed a vision for what we hope the land we are looking after will look like in the future, which is described in this short film.
Tell us about the ‘rewiggling’ of Swindale Beck: how important is this work to the overall Wild Haweswater project, and what benefits do you hope it will bring?
When we took on the farm tenancies in 2012 the beck as it flowed through Swindale stood out as a feature of the landscape that was badly in need of repair. Straightened at least 200 years ago in order to protect the valley’s hay meadows, its straightened, leveed course through which water flowed rapidly had stripped the bed of gravels suitable for spawning salmon. There were no trees along the beck’s banks. The levees, which were the result of generations of dredging, prevented water flowing back into the channel after flooding, resulting in stagnant pools sitting on the floodplain, impacting on both the botanical and agricultural value of the meadows.
In 2016, working in partnership with United Utilities, The Environment Agency and Natural England, a more natural course for the beck was returned. A meandering route, designed by geomorphologists based on a digital terrain model was excavated, exposing river gravels buried below. As soon as water was diverted into this new course, gravel bars, riffles, deep pools and fast running shallows began to form, all features which were missing from the straightened channel. Some sections were fenced out and trees planted alongside to provide shade. Other sections, which flow through a SSSI hay meadow, have had willow stakes pushed into the banks.
Within three months of the work being completed, salmon were observed spawning in the beck again, thanks to the improved quality of the substrate. The restored beck is 180m longer than the straightened course thanks to its meanders. It is better connected to the floodplain thanks to the removal of the levees, so contributes to reducing flood risk for people living downstream. This short film summaries the work done to the beck and in the wider valley.
How does your river restoration work interact with the wider landscape? How does the restoration affect other users of the valley?
The restoration is one element of wider restoration, including extensive blanket bog restoration in the upper catchment, tree planting and hay meadow restoration. We are the farmers in the valley, so it doesn’t have any impact on others. Although the restoration could be described as rewilding, much of it flows through traditionally managed hay meadows, which we crop to feed our livestock through the winter. It is powerful demonstration of how ecological restoration can be integrated with sustainable farming.
What balances do you strike in your work between guiding the restoration of habitat and ecosystem processes, and ‘letting the ecosystem go’ along new trajectories?
Most upland ecosystems in the UK have suffered so greatly over time that they are missing vital cogs that enable them to function. There is often limited seed source, so planting is often required in order to get a seed source re-established. In the longer run, if the grazing management is right, then this should allow subsequent natural regeneration.
Even when domestic livestock numbers and reduced to more naturalistic levels, deer can often have a major impact, preventing habitat restoration, woodland and scrub in particular. Our focus at Haweswater all about trying to re-establish the natural processes that will allow habitats to recover with less intervention in the longer term, but there’s a lot of work involved before we’ll get to that point.
What other restoration projects have inspired you at Wild Haweswater? And what key lessons would you pass on to other restoration practitioners seeking to carry out similar work?
Wild Ennerdale is a big inspiration, particularly their focus on natural processes and their use of extensive cattle grazing as a management tool. Carrifran Wildwood is fantastic too. They have completely transformed a valley from an open, heavily grazed state to a wonderful mosaic of woodland and flower rich upland grassland. Both of these projects have resulted from the meeting of minds of visionary people with shared energy and enthusiasm. They demonstrate how much good can be done for nature when we collaborate.
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Lee Schofield has recently published a book reflecting on the restoration work at Wild Haweswater. “Wild Fell: Fighting for nature on a Lake District hill farm” is out now.

Human-induced climate change is causing significant disruption to global ecosystems and the lives of billions of people who depend on them, according to the latest Intergovernmental Panel on Climate Change (IPCC) Working Group Report, released this week.
“This report is a dire warning about the consequences of inaction,” says Hoesung Lee, Chair of the IPCC. “It shows that climate change is a grave and mounting threat to our wellbeing and a healthy planet. Our actions today will shape how people adapt and nature responds to increasing climate risks.”
Titled “Climate Change 2022: Impacts, Adaptation and Vulnerability“, the Working Group Report states that the world faces multiple unavoidable climate hazards in the coming two decades under projected global temperature rises of 1.5°C. It highlights the increasing frequency and magnitude of extreme weather events such as heatwaves, floods and droughts that are placing species at risk of extinction and exposing millions of people to water and food insecurity.
The report – the second installment of the IPCC’s Sixth Assessment Report (AR6), which will be completed this year – highlights the need for rapid, deep cuts in global greenhouse gas emissions, coupled with local adaptation and mitigation measures.
“This report recognises the interdependence of climate, biodiversity and people and integrates natural, social and economic sciences more strongly than earlier IPCC assessments,” says Hoesung Lee. “It emphasises the urgency of immediate and more ambitious action to address climate risks. Half measures are no longer an option.”
The Working Group Report suggests that assessments of climate change impacts on freshwater systems have been limited in previous reports. As a result, this report devotes significant space to assessing how freshwater systems are responding to ongoing climate change, and the potential opportunities for mitigation and adaptation. These assessments build on reviews of cutting-edge freshwater science and management, from which six key themes are highlighted here.
Climate change is already significantly altering global freshwater ecosystems
The report states that strong and consistent global trends show that ongoing changes to the health of freshwater ecosystems can be attributed to climate change. It outlines that trends in freshwater species populations are strongly related to changes in the physical environment. It states that water temperature has broadly increased in lakes and rivers globally in recent years, whilst ice cover extent has declined in polar regions. Moreover, changes to river flows have reduced connectivity of habitats across many catchments, with more than half of global rivers undergoing periodic drying. Further, decreases in dissolved oxygen concentrations and changes to water mixing in freshwaters have also been widely observed.
All of these climate-caused habitat changes are increasingly putting freshwater species at risk. The report states that climate-driven population extinctions have been higher in freshwater ecosystems than in their marine and terrestrial counterparts in recent years. Ongoing climate change increases the risk of such extinctions: the report suggests that extreme 5°C warming would likely put 60% of terrestrial and freshwater species at risk of extinction.

Floods and droughts: the impacts of extreme events
Climate change is causing increased extreme weather events, including storms, heavy rainfall, heat waves and droughts, the report states. Whilst the impacts of such events on freshwater ecosystems can be significant – such as heat wave fish kills – their consequences on ecological functioning are not always well understood. For example, whilst extreme floods cause massive habitat disturbances, moderate floods can help cycle nutrients and sediment through a river system. Given their increasing frequency and magnitude, the report states that understanding how the impacts of extreme floods and droughts cascade through freshwater ecosystems is a key area for future research.
Corridors and connectivity: species migrations and climate change
The report highlights how some freshwater species, particularly fish, are migrating in poleward directions due to warming climates across North America, Europe and Central Asia. This means that in some areas warm-water fish species are displacing cool-water species, which in turn seek cooler upstream habitats at higher altitudes. However, such cool-water species risk local extinction if migration to suitable refuge habitat is impossible. These processes highlight the importance of environmental management which prioritises connectivity across watersheds, creating freshwater corridors which allow species to move with climate shifts.

Climate change effects on humans and freshwaters
Freshwaters provide an array of benefits and services to human communities, which may be limited by climate change, the report suggests. In particular, it highlights the potential effects of floods, droughts and ice melt on the quality and quantity of drinking water. Floods can contaminate drinking water supplies with pollutants, whilst droughts can reduce its availability. The report also highlights the risks to freshwater fisheries posed by climate-induced processes of eutrophication and ice melt.
Feedback loops: freshwaters as a source of greenhouse gas emissions
The report highlights how in recent years freshwater ecosystems have been increasingly recognised as an important source of greenhouse gas emissions into the atmosphere. Emissions of carbon dioxide and methane can occur from warming, eutrophic lakes, and from exposed sediments during droughts. This flags the potential for climate change-altered freshwaters to become additional sources of atmospheric greenhouse gases, thus strengthening climate feedback loops.

Nature-based solutions for climate adaption and mitigation
The Working Group Report outlines the importance of management and policy interventions focused on climate change adaptation and mitigation. Beyond pressing goals of reducing global greenhouse gas emissions, one key area highlighted is the potential of nature-based solutions. As introduced here, nature-based solutions aim to harness the potential of natural processes to help tackle socio-environmental challenges such as climate change.
“Healthy ecosystems are more resilient to climate change and provide life-critical services such as food and clean water,” says IPCC Working Group II Co-Chair Hans-Otto Pörtner. “By restoring degraded ecosystems and effectively and equitably conserving 30 to 50 per cent of Earth’s land, freshwater and ocean habitats, society can benefit from nature’s capacity to absorb and store carbon, and we can accelerate progress towards sustainable development, but adequate finance and political support are essential.”
The report highlights the potential of peatland restoration and rewetting in boosting carbon storage and benefiting freshwater biodiversity. Similarly, it highlights the role of catchment restoration around urban areas as a means of improving natural water filtration and buffering floodwaters.
More broadly, the report states a clear urgency in limiting warming through concerted and equitable climate action. “The scientific evidence is unequivocal: climate change is a threat to human wellbeing and the health of the planet. Any further delay in concerted global action will miss a brief and rapidly closing window to secure a liveable future,” states Hans-Otto Pörtner.
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This article is supported by the MERLIN project.

In December 2019, the European Commission presented its European Green Deal, a new set of policy initiatives aimed at making the EU climate-neutral by 2050. Described by Ursula von der Leyen, the president of the European Commission, as Europe’s “man on the moon moment,” the Green Deal has wide-ranging ambitions to support environmental protection, green economies, sustainable agriculture and technological innovation across the continent.
What is the European Green Deal?
But what exactly does the Green Deal aim to do, and how might it impact Europe’s freshwater ecosystems? A key underpinning to the Green Deal is its attempt to fundamentally shift European economies from dependence on fossil fuels and environmental exploitation towards low-carbon, sustainable models of growth. “The European Green Deal is our new growth strategy – a strategy for growth that gives back more than it takes away… We are determined to succeed for the sake of this planet and life on it – for Europe’s natural heritage, for biodiversity, for our forests and our seas,” explained von der Leyen.
This strategy will be achieved through a framework of regulation and legislation which sets clear targets for EU countries, including a net zero carbon emissions goal by 2050. As a result, the Green Deal represents a sign that concerns over climate change and environmental sustainability have risen to the top of European policy making. Moreover, it signals European action towards global environmental targets such as the UN’s Sustainable Development Goals, the Paris Agreement and UN Framework Convention on Climate Change.
Since its initial proposal, the Green Deal has sparked a flurry of new proposals, regulations and changes to EU law, including a Climate Law, Industrial Strategy, Circular Economy Action Plan, Farm to Fork Strategy, Biodiversity Strategy and Zero Pollution Action Plan. Overall, it is estimated that the implementation of the Green Deal will cost over €1 trillion, around half of which will come from EU budgets, and the remainder from national governments and the private sector. This budget includes a new Just Transition Fund which aims to support regions, industries and workers who face socio-economic challenges in achieving the goals of the Green Deal.

The Green Deal and European freshwaters
For all its ambition, what does the European Green Deal mean for freshwaters? Key aspects of the Green Deal related to freshwater ecosystems include the promotion of environmentally-friendly food production systems and the restoration of European ecosystems and their services. The Green Deal is designed to offer a framework through which existing EU policies such as the Water Framework Directive and Bathing Water Directive can be integrated towards these ambitious goals.
One key new policy, the EU 2030 Biodiversity Strategy, launched under the Green Deal umbrella in 2020, states that at least 25,000km of European rivers will be restored to a free-flowing state by 2030. The Strategy also highlights the role of freshwater protections in stemming biodiversity loss and mitigating climate change, for example through the restoration of wetlands.
Another important link between the Green Deal and freshwater management is a zero pollution ambition for the continent. In May 2021, the European Commission adopted the EU Action Plan: Towards a Zero Pollution for Air, Water and Soil, which sets out a vision for zero harmful pollution to air, water and soil by 2050, through a series of measures to prevent, remedy, monitor and report on pollution.
However, achieving these goals will require significant new measures, according to Dr. Magdalena Bieroza and colleagues, writing last year in the journal Science of the Total Environment. The authors argue that to achieve significant improvements in freshwater quality, the Green Deal and related policies must address the entire water pollution chain, from sources to impacts. They suggest that at present, existing policies only address the sources and impacts of water pollution in a piecemeal way.
Dr. Bieroza and colleagues highlight the importance of the Farm to Fork and (recently-revised) Common Agricultural Policies in tackling water pollution in Europe under the Green Deal umbrella. More broadly, their study highlights wider challenges of aligning ambitious Green Deal goals with complex and changing environmental pressures across the continent.
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This article is supported by the MERLIN project.
Freshwater salinisation: a research agenda for a saltier world

Freshwater ecosystems across the world are becoming increasingly salty, with significant consequences for their health and biodiversity, and the pressing need for more research, according to a new study.
Freshwater salinisation is caused by salts entering rivers, lakes and streams as a result of human activities such as mining and intensive agriculture. Increased dissolved salt concentrations in water can place stress on aquatic organisms and reduce habitat quality. The ongoing effects of climate change, such as drought and sea level rise, are exacerbating freshwater salinisation in some areas.
Salinisation: an emerging freshwater pressure
Despite this increasing global threat, scientists still have patchy knowledge about the causes and consequences of freshwater salinisation. In response, a new open-access study proposes a global research agenda to better understand and manage the salinisation of freshwater ecosystems.
“The global [salinisation] tendency of lakes and streams is a great challenge for freshwater biodiversity, the functioning of ecosystems and human societies that depend on them,” says Professor Miguel Cañedo-Argüelles, from the Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona.
“To address this challenge, we need a joint effort of the scientific community, practitioners, local communities and policy makers,” continues ICREA researcher Professor Sandra Brucet, from the University of Vic – Central University of Catalonia.
A scientific team from ten countries led by Dr David Cunillera-Montcusí from FEHM, University of Barcelona collaborated to provide an overview of current knowledge on the topic, and to provide directions for future research.

Improving global knowledge of freshwater salinisation
They suggest that global knowledge of freshwater salinisation has an unequal geography. For example, the ecological effects of salt spread on icy roads has been well studied in North America, but not in Europe. Moreover, there are large areas of Africa and South America where salinisation has barely been studied as a pressure on freshwater ecosystems. The authors also found that the salinisation of small freshwater habitats such as ponds – which are increasingly shown to be key for biodiversity across wide landscapes – is poorly studied.
This lack of knowledge is important, because scientists are increasingly showing that salinisation can negatively impact freshwater ecosystems. The authors write, “salinity is one of the main drivers of adaptation, speciation, and community assembly in aquatic systems.” Increasingly salty water can place significant stresses on the self-regulating fluid exchanges many organisms carry out with their environment. In some cases, this can cause species loss, altering the composition of freshwater foodwebs, and the impair the benefits – such as fisheries and drinking water – they can provide to human communities.
Freshwater salinisation can also cause significant alterations to habitat quality, for example by contributing to the acidification of water bodies and the mobilisation of toxic metals, or by altering natural water mixing patterns in lakes. In some areas, saltier freshwater ecosystems can become colonised by invasive saltwater species.
Preparing for a saltier world
Despite these threats, the study authors identify a lack of knowledge on the effects of different kinds of salts in aquatic environments, as well as their impacts at wider regional and landscape scales. They highlight that most existing salinisation studies focus on aquatic insects, meaning there is a need to study the responses of both microorganisms and top predators such as fish, reptiles and amphibians.
The need to understand the effects of freshwater salinisation on aquatic ecosystems, and the humans who depend on them, is exacerbated by the impacts of climate change. Ongoing alterations to patterns of rainfall and air temperatures globally have the potential to intensify salinisation by magnifying the effects of human pressures such as mining, urban run-off and intensive agriculture.
Accordingly, Dr. Miguel Matias, researcher at MNC-CSIC, concludes, ”with the collaborative effort of the international team of scientists that published the review paper, we want to promote this global effort in order to advance towards this direction and raise interest for this global problem that will lead us to a saltier world with many salinised lakes and rivers, and for which we must prepare.”
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What are nature-based solutions and why do they matter?

Open a tap in New York City and flows what many locals call the “champagne of drinking water”. New York is one of the few cities in the USA with a public drinking water supply that doesn’t rely on expensive filtration plants. And the reason for this “champagne” supply? The network of forests, streams, lakes and reservoirs in Catskill Mountains watershed to the north of the city. Estimates suggest that if it wasn’t for the natural filtration processes occurring in the watershed the city would have to invest more than $10 billion in water filtration facilities.
The natural processes occurring in the Catskill watershed thus provide a range of environmental, social and economic benefits to local communities. Such aspirations are at the heart of a recent turn in environmental management towards so-called “nature-based solutions”, which aim to use natural processes to help tackle socio-environmental challenges such as climate change, biodiversity loss and flooding.
Nature-based solutions: environments, societies, economies
Nature-based solutions are often designed to bring benefits to both people and nature. For example, planting native forests in watersheds can help naturally filter water supplies and buffer flooding, whilst restoring peat bogs can help provide biodiversity habitat and boost carbon storage. The IUCN estimates that such nature-based solutions have the potential to supply up to 37% of global climate change mitigation needs.
A commonly-cited definition of nature-based solutions from the IUCN highlights the focus on nature-society benefits, “Nature-based solutions are actions to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously providing human wellbeing and biodiversity benefits.”
In this definition we see the traces of linked concepts of sustainability and ecosystem services that have informed global environmentalism in recent decades. However, what is new about nature-based solutions is the impetus they provide for policy makers to support large-scale and ambitious environmental restoration to address contemporary issues. In so doing, the nature-based solutions concept aims to provide clear economic and social rationales for the value of protecting and restoring natural environments.

Supporting resilient ‘green’ societies and economies
As a result, nature-based solutions have become a central part of contemporary EU environmental policy, such as the European Green Deal, and in the Horizon 2020 programme. The European Commission defines nature-based solutions as, “Solutions that are inspired and supported by nature, which are cost-effective, simultaneously provide environmental, social and economic benefits and help build resilience. Such solutions bring more, and more diverse, nature and natural features and processes into cities, landscapes and seascapes, through locally adapted, resource-efficient and systemic interventions.”
Like the IUCN definition, we see the emphasis on the multiple benefits of natural systems, however, the EC definition adds the concept of building resilience into both urban and rural landscapes. Resilience here refers not only to how ecosystems will respond to emerging challenges such as climate change, but also how job provision and economic growth might be sustained within increasingly “green economies”. In Europe, therefore, nature-based solutions represent a significant tool for transformative change towards greener, climate-resilient societies.
Nature-based solutions are increasingly being deployed in freshwater environments, notably in the 17 flagship restoration sites across Europe managed by the MERLIN project. For example, the restoration of peatlands and wetlands in Sweden is targeted at increasing carbon storage and enhancing biodiversity (such as through the reintroduction of beavers). Similarly, the restoration of natural river channels and floodplains in the highly-modified Emscher catchment in Germany is designed to improve habitat, reduce flooding and create new spaces for recreation.

Nature-based solutions: questions, issues and futures
Nature-based solutions are increasingly being adopted in environmental policy and management, not only in Europe but across the world. But there remain significant questions for their adoption. Where should the line be drawn as to what counts as a ‘natural’ intervention? Which communities and stakeholders (human or non-human) might nature-based solutions benefit, and which might be overlooked?
In complex and often-uncertain contemporary landscapes, can all the potential pros and cons of a particular nature-based solution be fully considered? In addition to their benefits, could nature-based solutions unintentionally foster negative ‘ecosystem disservices’ in a landscape? And, significantly, given the centrality of economic benefits to the concept, can nature-based solutions remain apart from issues of corporate ‘greenwashing’ through schemes such as carbon offsetting through tree planting?
In response to such ongoing questions, in 2020 the IUCN provided the first ‘Global Standard for Nature-based Solutions’, offering eight specific criteria for their application. First, there is the need to clearly identify the social challenge to which the solution responds. Second, the value of the solution needs to be considered in terms of its effects across entire landscapes. Third, fourth and fifth are focused on the key pillars of sustainable development: environment sustainability, social equity and economic viability.
The sixth criterion addresses the need to identify trade-offs in decision-making between everyone affected by the solution, on both short- and long-timescales. Seventh, the need for an adaptive approach to learning through management is highlighted in designing solutions which evolve and improve over time. Finally, the IUCN highlight the need to mainstream nature-based solutions within national and international policy in order to underpin their long-term success. The IUCN criteria form the basis of a self-assessment tool for environmental managers using nature-based solutions.
Nature-based solutions offer rich potential in gaining support for environmental protection and restoration, by placing nature at the heart of social life. We will continue to follow their development and application, both in Europe and beyond, on this blog in the coming years.
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This article is supported by the MERLIN project.
Top 10 posts of 2021

In these slow days between Christmas and New Year we continue our annual tradition of looking back at the year’s top posts. There are encouraging signs that crucial freshwater issues are being taken increasingly seriously in environmental policy and management, with innovative new approaches to conservation and restoration being implemented.
However, the picture is still troubling for freshwaters: with multiple stressors including climate change, habitat loss and pollution all contributing to significant declines in aquatic biodiversity globally. But, with the growth in collaborations between dedicated freshwater scientists, policy makers, environmental managers and public activists across the world we have reason to be hopeful that 2022 could be the year in which we ‘bend the curve‘ of aquatic biodiversity declines, and safeguard our rivers, lakes, ponds, streams and wetlands for future generations.
You can explore all of last year’s posts here.
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Multiple stressors shape river ecosystems across Europe (January)

In recent years, freshwater scientists across the world have explored how the ecological health of rivers and lakes is impacted by multiple human stressors. Such stressors – for example, pollution, water abstraction, bank alterations and habitat loss – often act in complex combinations, which can variously intensify or reduce their individual impacts. Freshwater managers and conservationists have long known that aquatic ecosystems are affected by a wide range of human activities, but until recently there has been little evidence-based guidance on how to manage for their impacts. Recent multiple stressor research seeks to untangle how different stressors interact, the impacts they can have, and the management actions that are most effective for tackling specific multiple stressor combinations. A new study provides the first overview of how multiple stressors determine ecological status in European rivers. (read more)
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Wetlands: Havens of Life (February)

Communities around the world recently celebrated World Wetlands Day, an event held to raise global awareness about the vital role of wetlands in supporting biodiversity and human wellbeing. During online conversations around the event we discovered a fascinating short film titled ‘Wetlands: Havens of Life’. The film, made by author Julian Hoffman in collaboration with The Wetlands Initiative, documents the rich cultural and ecological diversity of the Prespa Lakes in Southern Europe. Julian is an award-winning landscape writer who has lived in the Prespa Lakes region since 2000. His most recent book Irreplaceable: The Fight to Save our Wild Places explores vital conservation and restoration projects in imperilled ecosystems across the world. We spoke to Julian to find out more about his film, the Prespa Lakes, and the value of wetlands. (read more)
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World’s ‘forgotten fishes’ in catastrophic decline (February)

Nearly a third of global freshwater fish species are threatened by extinction, according to a major new report compiled by 16 conservation groups. The World’s Forgotten Fishes report states that 80 species of freshwater fish are known to have gone extinct, with 16 of these extinctions occurring in the last year alone. Since 1970, populations of migratory freshwater fish have fallen by 76%, and large ‘megafauna’ fish species by a startling 94%. The report, published by a coalition of groups including WWF, IUCN, and the Alliance for Freshwater Life, highlights the rich variety of global freshwater fish species: the current known total of 18,075 species accounts for over half of all the world’s fish species, and a quarter of its vertebrate species. (read more)
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Towards a freshwater ethic: lessons from Aldo Leopold for contemporary aquatic conservation (March)

“All ethics so far evolved rest upon a single premise: that the individual is a member of a community of interdependent parts. The land ethic simply enlarges the boundaries of the community to include soils, waters, plants and animals, or collectively the land.” This is the core of early-20th Century American conservationist Aldo Leopold’s outlook on environmental management, or as it his commonly known, his ‘land ethic’. More than half a century later, then, could Leopold’s work be used to develop a ‘freshwater ethic’ which could strengthen contemporary aquatic conservation? According to a team of freshwater researchers writing in the Aquatic Conservation journal, there is rich potential to rediscover Leopold’s work in this way. (read more)
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‘Plastic is everywhere’: microplastics found in 1950s freshwater fish specimens (May)

Freshwater fish have been swallowing microplastics since at least the 1950s, according to a newly published study. Microplastics – tiny threads and fragments of plastic resulting from the breakdown of waste, clothing and cosmetics – are an increasingly important topic of environmental concern, having been found in deep oceans, on high mountain tops, and even in the atmosphere. A team of researchers examined preserved freshwater fish specimens from the Chicagoland region, USA, kept in the Field Museum collection. Four species in the museum collection – largemouth bass, channel catfish, sand shiners, and round gobies – had specimen records dating back to 1900. The team’s analysis shows that once plastic manufacturing became industrialised in the 1950s, microplastics began to significantly accumulate in the fishes’ bodies. (read more)
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Developing MEASURES for reconnecting migratory fish habitats in the Danube basin (May)

In 2019 we featured a major new freshwater project, MEASURES, founded to manage and restore ecological riverine corridors in the Danube River basins. Funded by the EU as part of the Danube Transnational Programme, MEASURES aimed to improve habitat quality and connectivity along the Danube in order to support populations of six threatened sturgeon species, as well as other migratory fish and wider aquatic biodiversity in the basin. Earlier this month, the project held its final conference, bringing together participants from diverse fields interested in the conservation and restoration of the Danube basin. “Our three year cooperation allowed major steps in gaining new knowledge on migratory fish in the Danube River Basin and transferring these insights into practice. MEASURES is an excellent example of cross-sectoral international collaboration to address an important aspect of freshwater biodiversity,” says project co-ordinator Thomas Hein. (read more)
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IPCC Climate Change Report: Three Key Themes for Freshwaters (August)

Humans are altering Earth’s climate in unprecedented and potentially irreversible ways, according to the latest Intergovernmental Panel on Climate Change (IPCC) Report, released today. The report is the sixth assessment of global climate science published by the IPCC since 1988, and is based on the collaborative review of peer-reviewed science by hundreds of experts across the world. It states that global climate change is widespread, rapid and intensifying, and that many ongoing observed climate changes are unprecedented in thousands, if not hundreds of thousands of years. The complex impacts of multiple climate change pressures on aquatic systems are increasingly well-documented. In this context, the IPCC report highlights three overarching impacts on freshwater ecosystems arising from its assessment. (read more)
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Rights of Rivers at the IUCN World Conservation Congress 2021 (September)

Today is the final day of the IUCN World Conservation Congress 2021, held in Marseille. The Congress has brought together over a thousand participants from government, academia, public and indigenous peoples’ organisations to set priorities for global conservation and sustainable development. The Congress programme states that environmental rights and equitable governance are crucial in protecting freshwater ecosystems, and supporting the human communities that depend on them. It asks, “How can existing laws, policies, and institutions be strengthened and adapted to ensure the more effective and sustainable management of water resources at the local, national and transboundary levels? How can we effectively strengthen governance and stewardship to maintain healthy watersheds, and address pollution and contamination?” One response to these questions comes in the form of the Rights of Rivers movement, highlighted at the Congress. The movement states that all rivers should be regarded as living entities that possess legal standing in a court of law. This means that ‘fundamental rights’ of rivers – such as free flows, protection from pollution, biodiversity habitat and ecological functioning – are given strong legal protections. (read more)
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Mainstreaming freshwater restoration in Europe through MERLIN (October)

Europe’s environments are in an alarming state. Despite decades of environmental action and policy, human activities continue to alter, degrade and destroy ecosystems across the continent. All of this comes with a cost, not only to the rich biodiversity European ecosystems support, but also to the human communities who rely on nature for food, water, jobs and well-being. As a result, there is a pressing need for damaged ecosystems to be brought back to life through ecological restoration across Europe. Freshwaters are key to such transformative change. As this blog has documented, freshwaters are vital ‘life support systems’ for both humans and wildlife alike. But what can we do about the situation? MERLIN, a major new EU-funded project, launched today, has ambitious goals to kick-start the restoration of Europe’s freshwater environments over the coming years. (read more)
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Bringing freshwater research and policy out from ‘beneath the water’s surface’ (December)

Global freshwater biodiversity is in big trouble. The latest WWF Living Planet report suggests that freshwater populations across the world have declined by an average of 84% in the last 50 years. This alarming trend is due to multiple pressures on freshwater ecosystems including climate change, habitat loss, over-harvesting and water pollution. The report suggests that biodiversity loss is happening much faster in freshwaters than on land or in the oceans. In recent years, we have covered a series of ambitious plans to halt freshwater biodiversity declines, including the Emergency Recovery Plan for Freshwater Biodiversity and Safeguarding Freshwater Life Beyond 2020. Earlier this year a major ‘horizon scanning’ paper highlighted twenty-five essential research questions to inform the protection and restoration of freshwater biodiversity. Across all these initiatives, what is clear is the pressing need to deepen our understanding of freshwater ecosystems and their threats, whilst also gaining widespread political and public support to help halt their global declines. Today a team of researchers representing 90 global scientific institutions strengthen this movement through a new global agenda for freshwater biodiversity research. (read more)
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Thanks for reading, and a happy 2022 to you! If you are in need of more freshwater stories, you can read our previous annual post round-ups for 2020, 2019, 2018, 2017 and 2016.



