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More Postcards from Heatwave Europe

August 17, 2018

Low water levels on Thirlmere in the English Lake District in late July 2018. 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 In Britain, at least, the weeks of hot, dry weather experienced this summer have recently been replaced by more unsettled conditions and regular thunderstorms.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.

You can read the first set of ‘postcards’ here.


In the Swedish county of Uppland, we have been racing to complete fieldwork for the BiodivERsA-facilitated CROSSLINK project before our streams dried out or went into extreme low flows. Fortunately, there was good snowfall over winter which meant the streams all started with high base-flows in spring. However, it is not difficult to imagine a scenario where a poor snow year coincides with another extremely dry summer, which could place catastrophic strains on systems already under pressure from human activities.

Notably, the spring transition this year was extraordinarily rapid, leading to record warm temperatures in May. This warming seemingly bolstered seasonal emergence of stream insects, leading to a noticeable pulse of riparian insect activity around our study sites early in the season. We hope to quantify the effects of this spatial subsidy on receiving terrestrial consumers using biomarker analyses.


A stream study-site near Uppsala in early May 2018. Image: Francis J. Burdon


Extreme low flows in the same stream in late June 2018 after a long period of hot, dry weather. Image: Francis J. Burdon

Another aspect of the CROSSLINK project is assessing the benefits of woody riparian buffers to stream ecosystems. In this year’s heatwave, our buffered sites in Sweden have been on average 0.5°C cooler than the un-buffered sites upstream. This observation adds further credence to calls for riparian plantings as a climate adaptation tool in catchments facing multiple pressures. However, we have noticed that our forested headwater reference sites all face hydrological challenges during the summer months. Whilst this natural feature of our systems has likely been exacerbated by drainage practices, there may also be a perverse tradeoff between the benefits of shading and the transpiration exerted by trees.

The severity of the drought in Sweden has caused an unprecedented number of wildfires throughout the country. Our study sites have not been affected, and with temperatures starting to cool and some much-needed rain, the situation seems to be stabilising. Similar to reports from Wales, we have experienced torrential thunderstorms in the past two weeks, leading to surface flooding in urban areas of Uppsala. However, like the situation in the UK, these rain events have only marginally improved the low-flow conditions in our streams. It is safe to say we wait with bated breath to see what more the weather will deliver in 2018.

Dr. Francis J. Burdon, Swedish University of Agricultural Sciences


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


The height of the ‘heatwave’ broke here in mid-July, and a threatened hose-pipe ban has been postponed thanks to some rain, cooler temperatures and a drop in water demand. However the hot, dry conditions through May, June and early July – with average air temperatures 2 – 2.5°C above the 1981 – 2010 average and rainfall being only between a third and just under three-quarters of the average for this time of year – have meant water levels in our lakes and rivers have declined.

By the end of July, river levels in a number of the rivers in the northwest of England were at historically low levels and reservoir stocks were much lower this year, particularly in Cumbria and the Lake District where levels were 10 – 30% lower than on average. So what are the impacts of these hydrological and meteorological conditions on some of the lakes in the Lake District?

temp levels2

Figure 1: Surface temperature data from Windermere, north basin. The blue line represents the 1981–2010 average, and the dotted lines one standard deviation from this average. The yellow line represents the 2018 data. All data are from the CEH Cumbrian lakes long-term monitoring programme.

At CEH we have been monitoring lakes in the Lake District since the 1940s, so we’re in a good position to see how this year fits into the longer-term pattern. We can see by looking at our long-term record of surface water temperatures, that average temperatures during May, June and July 2018 were between 2.4 and 4°C higher than the 1981–2010 average.  (See the example from Lake Windermere’s north basin in Figure 1).

The additional heating of the surface waters also means that the seasonal water column temperature stratification is particularly strong this year, meaning the difference in temperature between the surface and deep water of Windermere is around 16°C, which also has implications for aquatic life in the lakes.

cyanobacteria levels

Figure 2: A measure of total algal biomass, chlorophyll a, for Blelham Tarn and Windermere, north basin. The blue line represents the 1981 – 2010 average and dotted lines are 1 standard deviation from the average. The yellow line represents the data from 2018. All data are part of the CEH Cumbrian lakes long-term monitoring programme.

Interestingly, the warmer water has not – during this early part of summer at least – increased the overall amount of algae in the lakes. One measure of algae levels – total chlorophyll a – is not generally above the long-term average (See Figure 2).

At first this may seem at odds with the incidences of cyanobacteria blooms that have been reported for a number of Lake District lakes. However, these species of algae – or more strictly speaking, photosynthetic bacteria – are particularly well adapted to the warm, stable water column conditions that we have been experiencing, because they have the ability to float to the surface and out-compete other species for light. Their buoyancy also means that they can be readily moved by water currents into shoreline areas where they accumulate and become a problem for humans and other animals.


Examples of some of the cyanobacterial genera present in the Cumbrian lakes Windermere and Esthwaite Water this summer. From top left clockwise: Microcystis, Anabaena (straight form), Anabaena and Woronichinia, Anabaena (coiled form) and Aphanizomenon. Image: CEH

Our algal community data suggest that this group are particularly dominant this year, with cyanobacterial genera Anabaena, Aphanizomenon, Woronichinia and Microcystis being present in the community. The lower amount of algae that we have seen this year compared to the long-term average, is likely to be a response to the nutrients available, which enable the algae to grow.

The depletion in the surface water concentrations of these nutrients has been particularly rapid this year, which may be limiting the overall amount of algae that is being supported. The more recent rainstorms at the middle to end of July may have altered this availability by bringing in nutrients from the lake catchments, which could promote more algal growth over the remainder of the summer.

Dr. Ellie Mackay, UK Centre for Ecology & Hydrology, Lancaster, UK.

Read Part One of ‘Postcards from Heatwave Europe’

Postcards from Heatwave Europe

August 3, 2018

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. Meteorologists predict that the European temperature record of 48C (118.4F) set in Athens in July 1977 could be broken this weekend in Spain and Portugal.

In Europe, the heatwave has been caused by the stalling of the northern hemisphere jet stream, which generally brings cooler Atlantic weather over the continent. As a result, a huge ‘pocket’ of hot, dry air has been present over Europe (particularly northern regions) in recent months.

Analysis of the heatwave in northern Europe between May-July of this year by the World Weather Attribution group suggests that this extreme weather has been made at least twice as likely by ongoing climatic changes.  Similarly, speaking recently to The Guardian about this year’s global weather extremes, climate scientist Prof. Michael Mann, at Penn State University said, “This is the face of climate change. We literally would not have seen these extremes in the absence of climate change.”

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.

The first responses are collected here, and more will be published in the coming weeks. If you would like to submit your own observational ‘postcard’, please email


Water levels in tributaries of Lake Nisser in Norway are extremely low, and in some cases completely dry. Image: Anne Lyche Solheim


I am currently on holidays close to Norway’s 10th largest lake (Nisser in Telemark) where the water level is extremely low, and most of the tributaries have dried out completely, or have become reduced to minor streams. Yesterday, a farmer in the local neighbourhood came with his tractor and a big water tank to get water from the lake for his cattle, who are suffering in a grazing area in the hills, where all the streams have tried out. This has never happened before.

The well we use for water supply to our summer house here have lost two-thirds of its water, so we don’t know how long we can stay here before the well runs dry. There is absolutely zero re-charge over the past weeks and months now. 12th of June was the last time we had any substantial rain in South-Eastern Norway.

The air temperature during daytime varies from 28 to 31C, and it’s been like that since mid-May. There are almost no insects, except a few bumble bees. The grass is mostly yellow and the grain crops are likely to be < 1/3 of normal. There is a crisis for cattle farmers, as they do not have enough fodder for them, so a lot has been slaughtered.

The surface water in the lake is now 25C, which is highly exceptional (although perfect for swimming). The littoral zone is completely dried out.

Dr. Anne Lyche Solheim, Niva


The weather has been completely weird this year! We had no winter: no snow, no rain, and very dry and warm weather. Between May and mid-June we had extreme rains with flash floods all around the country. Lakes and rivers across Turkey suffered from dissolved organic carbon problems, which are normally unheard of.

Now since mid-June, every day is record breakingly hot. In this heatwave, many small ponds are drying out, and lake levels are going down more than 1 cm/day. Evaporation is very high, which leads to an increase in salinity and conductivity in the water column. Of course, we’re seeing widespread algal and cyanobacteria blooms as water temperatures rise and nutrient concentrations increase.

Prof. Meryem Beklioğlu, Middle East Technical University


Huge blooms of blue-green algae in brackish coastal waters in the Gulf of Finland and Archipelago Sea. Image: ESA Copernicus Sentinel Data, 16 July 2018, processing by SYKE


With wildfires blazing in Greece and Sweden, the heatwave across Europe has not left Finland cold either. Temperatures were record-breaking both in May and July, with average temperatures 2–5 degrees above long-term mean values. This has not come without responses in Finnish freshwaters.

In Lake Enäjärvi in Southern Finland, mass deaths of lake mussels occurred, likely due to oxygen depletion in the exceptionally warm water. Also fish kills were observed in some lakes across Southern Finland, and extensive blooming of cyanobacteria occurred in many lakes. The hot weather also boosted a massive blue-green algae bloom in July in the Gulf of Finland and parts of the Archipelago Sea.

In inland fish farm ponds, salmonids have been suffering the prolonged heat. Across fishing sites in streams, there were pleas to temporarily cease salmonid fishing as catch-and-release might cause additional fatal stress to the fish already stressed by warm water.

Dr. Jukka Aroviita, Finnish Environment Institute (SYKE)


Flash flooding in Cardiff, Wales, after weeks of hot, dry weather. Image: Steve Ormerod


In Wales — as in much of the UK — we’ve been heading for what has looked like the driest summer since modern records began in 1961. River discharge levels have been very close to record lows throughout July, while air temperatures at or near 30C in mid and south Wales have meant the region’s rivers have been at 24C or higher. Parallels have drawn increasingly with the major drought of 1976, surpassing the extremes of more recent events in the early 1990s or 2003.

All of these past drought years brought significant ecological effects. In 1976, low water levels, high temperatures and attendant low oxygen concentrations in the River Wye (now a Natura 2000 river) were exacerbated by the dieback and decomposition of mats of Ranunculus fluitans causing extensive salmonid mortality. Here, at the south-west edge of the Atlantic Salmon’s European range, recruitment falls substantially following hot, dry summers like 2018, so we expect echoes of current conditions next year and beyond.

It’s very likely that the full effects of the 2018 drought will only be known retrospectively. As an example, droughts during several summers in the early 1990s were subsequently shown to have led to the widespread extinction across Wales of the cool-water flatworm, Crenobia alpina — and it hangs on now only where thermally damped subterranean discharge keeps water temperatures below 12-13C.

The current hot, dry conditions over Wales came to an abrupt end over the weekend of July 28th/29th, when 40-60 mm of rain fell over different parts of the nation. Although there was localised urban flooding, effects on river levels have been small or transient.

Hydrographs Wye tributaries

Hydrographs of tributaries of the River Wye, Wales, showing low water flows, even after heavy rain in late July 2018. Image:

These two 30 day hydrographs from the Ithon and Irfon – respectively left and right bank tributaries of the Wye – illustrate modest effects on discharge that also reflect local geological damping and slightly lower catchment altitude of the Ithon.

With a return to drier conditions forecast for much of July and August, the 2018 summer may yet break more records.

Prof. Steve Ormerod, Cardiff University

More information:

The AQUACROSS Information Platform: linking aquatic datasets across Europe

July 27, 2018

aquacross ip screen

A new open-access online platform hosting datasets on European aquatic ecosystems, biodiversity and Ecosystem-Based Management has been launched this month. The AQUACROSS Information Platform (IP) is designed to provide scientists and environmental managers with integrated datasets on aquatic systems across Europe at a variety of scales.

The information platform has been produced through a collaboration between the UNESCO Intergovernmental Oceanographic Commission and the AQUACROSS project. AQUACROSS is an EU Horizon 2020 project which aims to support European efforts to protect aquatic biodiversity and ensure the provision of aquatic ecosystem services.

The project, which has been active since 2015, seeks to advance both knowledge and application of Ecosystem-Based Management in aquatic ecosystems, to support the achievement of EU 2020 Biodiversity Strategy Targets.



AQUACROSS project co-ordinator Manuel Lago from the Ecologic Institute in Berlin says,

“The AQUACROSS IP is an unprecedented effort to combine relevant data for the interdisciplinary analytical needs required for the protection of aquatic biodiversity. The AQUACROSS IP ensures a single point of entry for freshwater, coastal and marine related information to be used in general and case-study integrative assessments.”

The AQUACROSS IP is designed to help support more effective European environmental policy and management by helping share and connect existing spatial datasets at local, regional, national and international levels.

The information platform will help provide water managers and policy makers with a clearer, more detailed picture of how European waters – both freshwater and marine – are responding to the multiple pressures from human activity and climate change.

AQUACROSS case studies

The eight AQUACROSS case studies which can be explored in the new Information Platform. Image: AQUACROSS

Users of the AQUACROSS IP can access datasets from aquatic case studies across Europe, and analyse, visualise and publish the information they contain. At present, there are 580 different datasets available on the platform, many of which were produced through research in eight AQUACROSS case studies.

These case studies are:

  • North Sea – trade-offs in ecosystem-based fisheries management to achieve Biodiversity Strategy targets;
  • Intercontinental Biosphere Reserve of the Mediterranean, Spain/Morocco – nature-based solutions in transboundary aquatic ecosystems;
  • Danube River Basin – harmonising inland, coastal and marine ecosystem management to achieve aquatic biodiversity targets;
  • Lough Erne, Ireland – management and impact of Invasive Alien Species;
  • Ria de Aveiro Natura 2000 site, Portugal – integrated management of a complex socio-ecological coastal ecosystem;
  • Lake Ringsjön and Rönne å Catchment, Sweden – understanding eutrophication processes and restoring good water quality;
  • Swiss Plateau – biodiversity management of rivers in densely populated landscapes;
  • Azores – ecosystem-based management in a Marine Protected Area with multiple human pressures.
Swiss Plateau AQUACROSS

Looking over the Swiss Plateau, one of the AQUACROSS case studies. Image: AQUACROSS

The AQUACROSS IP structure has been designed following guidance from the European INSPIRE Directive, which encourages environmental data sharing and access initiatives. The platform has been developed based on existing open-source CKAN software, following the Open Source Software Strategy and the New Interoperability Framework recommendations from the European Commission.

Juan Arevalo from the IP developing team working at IOC-UNESCO says,

“The development of the AQUACROSS Information Platform is based on CKAN software. This open source framework allowed us to integrate all the requirements from our project stakeholders. I would encourage anyone to use CKAN to develop open data portals given its interoperability with other system and the flexibility for development.”

The AQUACROSS IP is an ongoing, growing project. New resources will be added to the platform in the future, and users are encouraged to contact the managers of the IP with suggestions of relevant datasets which could be linked to the platform. The contact email is – aquacross.IP (at)

More information:

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

July 20, 2018
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.

What is ecological status?

Ecological status is an assessment of the structure and function of aquatic ecosystems, and is intended to show the ecological impacts of pressures such as pollution and habitat degradation. It is calculated based on monitoring of biological quality elements (such as fish, insects and plankton), physico-chemical elements (such as nutrient levels, organic pollutants and acidification), and hydromorphological elements (such as water flow, channel shape, and barriers such as dams and weirs). Broadly, then, ‘good’ ecological status means that communities of plants and animals can thrive in aquatic habitats which show minimal impacts of human alterations. ‘Good’ ecological status is the goal for water management under the Water Framework Directive.

EU eco status 2018

Image: EEA 2018

Key pressures on European surface waters

The most significant pressures on surface water bodies were from hydromorphological alterations (such as river straightening, water impoundment and the construction of dams and weirs) and diffuse pollution (particularly of fertilisers from agriculture). Mercury pollution – from atmospheric deposition and urban waste water treatment plants – was a key cause of many water bodies failing to reach good chemical status. The countries with the lowest proportion of water bodies in ‘good’ ecological and chemical status were in heavily-populated and industrialised areas of northern Europe – particularly in south-east England, Netherlands, Belgium and Germany.

Groundwaters in better condition

Groundwaters were generally found to be in better condition across Europe, with 74% of European groundwater areas found to be in good chemical status, and 89% found to be in good quantitative status (i.e. their water stock). Nitrates from agricultural activity and sewage systems were the primary source of groundwater pollution. Water abstraction for public water supplies, agriculture and industry was the key cause of groundwaters failing to achieve good quantitative status.

EU chemical pollutants

Sources of water pollution across Europe. Image: EEA, 2018

Reflecting on the second River Basin Management Plan reports

It is difficult to properly compare the results of the first and second RBMPs, as European water monitoring programs have been expanded and improved over their period of implementation. But, whilst these monitoring improvements have given scientists and managers a better picture of the stressors and pressures affecting European waters, there appears a long way still to go in successfully mitigating their harmful effects.

“Thanks to the implementation of European water legislation in the Member States, the quality of Europe’s freshwater is gradually improving, but much more needs to be done before all lakes, rivers, coastal waters and groundwater bodies are in good status. Tackling pollution from agriculture, industry and households requires joint efforts from all water users throughout Europe,” says Karmenu Vella, EU Commissioner for Environment, Maritime Affairs and Fisheries.

The report states that most European member states have made significant efforts to improve water quality and reduce hydromorphological pressures on their surface waters. The original intention of the Water Framework Directive – implemented in 2000 – was that all member states should achieve good status in their surface and ground waters by 2015. This has obviously not been achieved, despite the coordinated efforts of policy makers, water managers and scientists across Europe under the WFD.

It is increasingly evident, however, that the ecological impacts of aquatic restoration measures can take a number of years to be realized, especially in complex multiple stress environments. The authors of the EEA report optimistically suggest that by the time the third RBMPs (taking place 2019-2021) are reported upon, the conservation and restoration measures implemented in the first two rounds will have caused significant positive progress towards good ecological status in water bodies across Europe.


‘Making room for the river’ on the Swindale Beck restoration project in the English Lake District. Image: Lee Schofield | RESTORE Project

The promise of integrated water management

The report calls for an increased focus on integrated water management as a means strengthening WFD implementation and impacts. Its authors highlight three areas in which this could be achieved. First, they advocate the use of management concepts such as the ecosystem services approach and ecosystem-based management as a means of co-ordinating efforts across related EU policies on the marine environment and terrestrial biodiversity. Second, they highlight the potentials of ecological management which works with dynamic natural processes, such as river and floodplan restoration through ‘Room for the River’ type schemes.

Finally, they call for better co-operation between water authorities and other sectors such as agriculture, transport and energy. They highlight Europe 2020 – the EU’s strategy for the growth of a ‘greener’, more environmental economy – as a framework for fostering sustainable water management across sectors.

“We must increase efforts to ensure our waters are as clean and resilient as they should be — our own well-being and the health of our vital water and marine ecosystems depend on it. This is critical to the long-term sustainability of our waters and in meeting our long-term goals of living well within the limits of our planet,” says Hans Bruyninckx, EEA Executive Director.

Read and download the European Environment Agency, “European waters: Assessment of status and pressures 2018” report here.

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

July 4, 2018

Clear waters in 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 – University of Natural Resources and Life Sciences at the Institute of Hydrobiology and Aquatic Ecosystem Management in Vienna.

Key themes in river management

The book is split into four sections. The first gives an overview of some of the key themes in current river management, namely human impacts, mitigation and restoration. Historical human river uses and impacts are surveyed alongside a series of contemporary river pressures, including alterations to river morphology and hydrology, dam construction and hydropeaking, sediment dynamics, habitat fragmentation, nutrient pollution and recreational fisheries.

The section encompasses emerging threats to river health and status, particularly in chapters by Florian Pletterbauer and colleagues on climate change, and by Ralf B. Schäfer and Mirco Bundschuh on chemical pollution.


Diverse woody habitat on the Lafnitz River in Austria. Image: Graf & Schmidt-Kloiber

Approaches in contemporary river management

The next section provides examples of contemporary approaches for river management and governance. Again, the focus is extremely timely, covering relevant legislative frameworks, integrated river basin management, adaptive management and transboundary water resource management, alongside methodologies for sampling and archiving biological data, such as in Astrid Schmidt-Kloiber and Aaike De Wever’s chapter on Biodiversity and Freshwater Information Systems. Schmidt-Kloiber and De Wever outline the value of online networks for freshwater data such as the Freshwater Information Platform.

A theme that runs through the book is that river ecosystems should be understood (and managed) as integrated ‘social-ecological systems’ in which nature and culture interact. As a result, this second section provides guidance and resources on identifying ecosystem services in river basins, and in fostering public and Non-Governmental Organisation (NGO) engagement and education in river management. Chapters on this theme are written by Kerstin Böck, Michaela Poppe, Christoph Litschauer and colleagues.


Sunset on the urban Danube River in Vienna. Image: Carola Moon | Flickr Creative Commons

Case studies of river management

The third section provides five case studies of river basin management, which illustrate and tie together many of the themes outlined in the previous sections. Three aspects of water management – hydropower, floodplain dynamics and uses, and sturgeon populations – on the Danube River in Central and Eastern Europe are described. These three case studies – written by Herwig Waidbacher, Stefan Preiner, Thomas Friedrich and colleagues – give an indication of the many challenges associated with the environmental management of a large, transboundary river with diverse habitats and competing human interests.

In Burkina Faso in West Africa, Andreas Melcher and colleagues discuss the need for co-ordination of fisheries management at national and local scales, supported by ecological monitoring programs, as a means of supporting sustainable fisheries for local communities. Finally, on the lowland Tisza River in Eastern Europe, Béla Borsos and Jan Sendzimir outline the steps needed to develop an integrated land development (or ILD) management approach in a complex and dynamic river basin.


The frozen Tisza River at Szeged, Hungary. Image: Zoltán Bagi | Flickr Creative Commons

Adaptive and interdisciplinary approaches to managing river systems

In the fourth and final section, the editors draw the book together, emphasising the need for river management to understand the ways in which social and environment systems link and interact in river basins. They highlight the possibilities of new ecological monitoring techniques as well as data management and mining techniques to inform river management, but underline the need for management to be adaptive to an increasingly complex and uncertain world.

Co-editor Stefan Schmutz says, “Despite a rich history of publications on riverine ecosystem management, this book is the first to concisely convey to a broad audience of students, academics and practitioners the frontiers of science and policy for sustainably restoring and managing rivers.”

Co-editor Jan Sendzimir continues, “Unprecedented uncertainty from global change requires an approach that integrates riverine ecosystem understanding and management requirements and options within an interdisciplinary framework. This book applies such a framework to show through a number of case studies how ecosystem and management theories and applications can be successfully used to re-establish and sustain the functional vitality of riverine ecosystems.”


The Open-Access e-book

Arranged as a series of short, accessible chapters, and richly illustrated with colour photographs and diagrams, Riverine Ecosystem Management: Science for Governing Towards a Sustainable Future is likely to prove useful for water managers, academics, students, policy makers and NGOs. Its clear style makes it open to interested non-specialists, too. The e-book also helps communicate a variety of research findings from EU- funded projects, including AQUACROSS, MARS and BioFresh.

There is clearly demand for such a publication – so far the e-book has been downloaded over 53,000 times in two months. For anyone seeking to understand the key debates, approaches and directions in contemporary river management, this is an invaluable resource.

Riverine Ecosystem Management: Science for Governing Towards a Sustainable Future. Published by Springer (Open-Access)

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

June 20, 2018
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 project began in 2014, and investigated how the complex ‘cocktails’ of stressors such as water pollution, habitat loss and climate change affected ecological status and ecosystem services in rivers, lakes and groundwaters across Europe.

The focus of the MARS project was tailored to support water managers and policy makers, in particular through advising the implementation and 2019 update of the Water Framework Directive and the Blueprint to Safeguard Europe’s Water Resources.

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. This blog post gives a brief overview of some of the research highlights, and more detailed information can be found in the project report.

3.Luftbild_Seelabor_© HTW Dresden-Oczipka

The IGB LakeLab in Lake Stechlin, Germany – a ‘floating laboratory’ for MARS experiments. Image: HTW Dresden-Oczipka

Multiple Stressor Research and Management

An initial MARS literature review of 219 existing journal articles on multiple stressors found that nutrient stress was involved in most (71–98%) of multiple stress interactions in rivers, lakes and estuary (or ‘transitional’) waters, and just under half (42%) of those in groundwaters. Their impacts were different depending on habitat type, mostly as a result of different hydromorphological (i.e. the water body banks and bed) characteristics and alterations. As a result, nutrient enrichment and hydromorphological alteration was the most common stressor pair overall, particularly in rivers and transitional waters.

MARS research was carried out at three different scales. At the water body scale, experiments with mesocosms and river flumes were used to investigate stressor interactions, and their impacts on ecological status and ecosystem services. At the catchment scale, modelling and empirical approaches were used to characterise the relationships between multiple stressors and ecological responses, functions and services, across 16 European river basins.

Finally, at the European scale, large-scale spatial analyses were carried out to identify relationships between stressor intensity, ecological status and service provision for large transboundary rivers and lakes. This research produced a series of European multi-pressure maps, with threshold values for four important pressure types, and a Stressor Analysis Tool for water managers.


The HyTEC field station in the Austrian Alps – the site of MARS stream experiments. Image: Christian Feld

Key messages from MARS

Around one-third of the 156 MARS case studies across Europe showed significant multiple-stressor effects. As a result, it can be confidently stated that multiple stressors are an important contemporary topic for aquatic science and management. However, a key message from MARS research is that there are rarely predictable relationships between stressor causes and biological effects, and that the characteristics of the local environment can mask or interfere with observed stressor effects.

As a result, it is necessary to investigate and manage the multiple stressor interactions and impacts for individual water bodies and river basins depending on their local biological and geographical characteristics. These can be assessed, diagnosed and managed using a suite of MARS online tools.

In short, what is required is aquatic science research that investigates the direct causes of deteriorated ecological status in rivers and lakes across Europe, a task which can be aided by advances in multiple stressor data collection and diagnostics. This is a key focus for managing and restoring complex aquatic environments under multiple pressures, both now and in the future.

mars tools

The MARS online tools hosted on the Freshwater Information Platform.

Multiple Stressor Tools

MARS project findings have been integrated into practical and accessible online tools to support water management.

They include:

  • Freshwater Information System – including an information library and factsheets on multiple stressors, ecosystem services, case studies and storylines for future environmental scenarios, alongside a model selection tool and guidelines for river basin management;
  • Diagnostic Tool for Water Bodies – designed to help water managers diagnose and mitigate multiple stress impacts on rivers and lakes;
  • Model Selection Tool – an overview of 21 available computer modelling tools for river basin management;
  • Scenario Analysis Tool – allows users to visualise and map multiple stressor interactions and impacts (both present and projected) at the European scale;
  • Bayesian Belief Models – designed to help predict biological responses to aquatic conservation and restoration measures under projected future environmental scenarios (see approach here).
mars threshold visuals

Visualisation of an additive pair of stressors – riparian vegetation alteration and phosphate levels – and how they might be managed towards good ecological status, as shown by the diagonal threshold line.

One innovative MARS output for water managers is the visualisation of how stressor-pairs can be managed towards good ecological status. Individual stressors are shown on the x and y axes of the ‘heat map’ diagrams, which are generated by computer modelling, and show a threshold line across which multiple stressor levels should be reduced in order to achieve good ecological status.

Summing up

Reflecting on the last four years, MARS project co-ordinator Sebastian Birk says,

“MARS was a fascinating project, joining the forces of highly skilled scientists across Europe towards unraveling the multi-stressor maze. I feel very honoured for this chance of coordinating such a great team. Most project partners knew each other since the early days of the Water Framework Directive, and this long-standing confidence and trust in each other made this project a delight. Daniel and me would like to express our sincere thanks to all MARS colleagues for this memorable experience! With posting the final project report, this will be kind of the last ‘official’ MARS blog entry. However, there is much more on MARS and beyond, so stay tuned to this channel.”

Read the MARS Final Report (pdf)
Read the ‘Messages from MARS’ blog post

Explore the MARS website

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

May 30, 2018

Restored river section five years after restoration with riparian vegetation consisting of grasses, shrubs and trees. 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.

Rivers are increasingly threatened by pollution, habitat modification and over-exploitation. Based on the results of the first Water Framework River Basin Management cycle, in 2012 the European Environment Agency (EEA) concluded that more than half of the European river network is damaged by severe human alterations. This picture appears even worse when individual country’s results are considered.


Riparian vegetation is often degraded to a one-row tree line. This may provide shade during summer, yet fundamental functions of riparian vegetation such as nutrient and fine sediment retention cannot be fulfilled. Photo: Christian K. Feld

River restoration approaches generally seek to improve river health, but often struggle with the identification of suitable management options. The team of researchers behind the new study addressed this need during the EU MARS project by reviewing available scientific literature. The scientists analysed the ecological role of riparian vegetation types as well as their configuration and spatial extent. Riparian features were then related to the level of restoration success observed in individual studies.

These results can then be applied to help guide future river restoration activities. Restoration success was evaluated through measures such as the efficiency of nutrients and sediments retention or water temperature ‘dampening’ as a result of riparian vegetation. Over a longer term, the effects that riparian vegetation had on riverine plants and animals could be evaluated.


Benthic invertebrate (caddisfly larvae) that feeds on leaves from riparian shrubs and trees. Photo: Aquatic Ecology, University of Duisburg-Essen

Based on the reviewed literature, the study found that woody riparian vegetation had consistent effects on the supply of leaf-litter and large wood to rivers. Leaves are a fundamental food source for riverine insects in upland rivers, where primary production is strongly limited, and where the food web of aquatic organisms relies on the input of terrestrial carbon.

Woody debris – such as fallen trees, tree trunks, branches and twigs – often increases habitat quality and variety in rivers. Besides the input of organic material, bankside vegetation also provides shade and can effectively ‘dampen’ water warming in spring and summer.

However, despite the observed positive effects of riparian vegetation, this review article also revealed weak and inconsistent effects on the biological quality and diversity of river organisms after riparian restoration. Unfortunately, the reasons behind this finding remained unclear, given that just a small fraction of the reviewed studies included biological effects at all.


Large woody debris in the restored Lippe River in Germany. Image: Benjamin Kupilas | REFORM

Leader of the study, Dr. Christian Feld said, “Land management such as farming or forestry are essential for society – but can damage rivers downstream. We therefore need ways to reduce their unwanted effects, and management of the riparian zone has long been proposed as a cost-effective and local solution. Our evidence shows that riparian restoration can be effective in offsetting some problems, but not all. Larger-scale problems such as pollution from agricultural chemicals or sediments will need larger-scale solutions applied through improvements in the management of whole river catchments.”

Feld highlights the unclear effects of riparian restorations in the retention of nutrients and sediments originating from farmland on the floodplain. The study showed that only riparian plantations that combined trees, shrubs and grasses could effectively reduce nutrient and sediment pollution. However, even then, riparian restorations had only a limited effect where the catchment further upstream was intensively used by agriculture. In contrast, positive effects were more pronounced if riparian restorations took place in the upper parts of the catchment, where the aquatic environment is stronger linked to the riparian conditions.

Professor Steve Ormerod – Co-Director of Cardiff University’s Water Research Institute and co-author of the study – added, “This whole issue is one that needs more holistic ecosystem management. Fresh water is a crucial human resource that needs care, maintenance and sometimes very expensive treatment before it can be supplied to people.  Freshwater ecosystems are also losing biological diversity at an alarming rate globally because they are not well protected. We need to step up efforts to balance productive land use against these downstream costs – and our work shows that this needs a blend of local riparian solutions as well as improved large-scale thinking.”


Overview of a restored river section five years after restoration. This riparian zone can effectively buffer the river system from adverse land use impacts on the floodplain, while the shade and organic material provided by the vegetation can promote the instream biology. Photo: Viktoria Berger.


C.K. Feld, M.R.P. Fernandes, M. T. Ferreira, D. Hering, S.J. Ormerod, M. Venohr, C. Gutiérrez-Cánovas. (2018) Evaluating riparian solutions to multiple stressor problems in river ecosystems — A conceptual study. Water Research, 139, 381-394.

The work was funded by the EU MARS project under project No.: 603378

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