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9th European Pond Conservation Network Conference announced

February 7, 2020
Shooting Close: a restored pond. Image: Richard Walton

A note from Dr. Richard Walton:

We are thrilled to announce the 9th European Pond Conservation Network Conference which will be held at University College London over 18-22 May, 2020.

Responding to the considerable need to conserve European ponds, the conference will combine pond biology, hydrology and landscape ecology with pond conservation practice. We welcome and encourage both scientists and conservation practitioners to attend and present their observations.

Please visit the conference website for further information, registration details and to submit an abstract. The deadline for abstracts is 28th February 2020 and the Early Bird deadline for registration is 20th March.

We hope to see you at the meeting – a four-day celebration of ponds and pond people!

Kind regards,

The EPCN 2020 Organising Committee

Eavesdropping on underwater worlds: the potential of aquatic ecoacoustics

January 30, 2020
Acoustic Ecologist Dr Simon Linke, who co-edited the special journal issue on aquatic ecoacoustics. Image: Griffith University

Could listening to the underwater sounds made by freshwater life help us better document and protect aquatic ecosystems? A new special issue of the Freshwater Biology provides intriguing evidence to suggest that it could.

Acoustic monitoring has emerged as a key tool for ecologists and conservationists in recent years. Bioacoustics (the study of sounds produced by or affecting living things) and ecoacoustics (the study of environmental sounds relating to ecosystem processes) continue to grow in popularity as approaches to ecological monitoring.

These approaches centre on the idea of passive acoustic monitoring, or PAM, where researchers place autonomous acoustic sensors (aka microphones) in study sites to capture sound recordings of the environment over time.

The recordings – whether transcribed by human researchers listening back, or by computer algorithms – can then be used to calculate biodiversity metrics such as species abundance, behaviour and phenology. Technological advances increasingly make PAM an affordable, long-term and non-invasive ecological sampling approach for researchers: a ‘listening ear’ on a changing world.

Ecoacoustics can detect and monitor water birds and amphibians, aquatic insects, fish, processes of sediment transport and gas exchange, and human activities. Image: Linke et. al. (2020)

However, the use of such acoustic monitoring techniques has yet to be fully explored or adopted in freshwater systems. The new special issue, edited by Dr Simon Linke, Dr Camille Desjonqueres and Dr Toby Gifford, outlines the opportunities acoustic monitoring offers to freshwater researchers and conservationists, in an effort to raise awareness of its potential.

“Monitoring freshwater ecosystems is time consuming and costly. Using acoustics enables us to observe what is going on 24/7,” says Dr Desjonqueres. “We took over the editorial desk of Freshwater Biology for an issue,” Dr Linke continues. “We invited the biggest names in the field to help us tackle some of the key steps towards operationalising acoustics in the freshwater realm.”

The special issue contains nine studies that investigate underwater acoustics (including the work by Ben Gottesman and colleagues which we covered last year), and three studies on water birds and frogs. Tracing a lineage of describing underwater sound back to Aristotle, the editors identify six key challenges for the widespread uptake of freshwater ecoacoustic monitoring.

1. Characterising sounds and linking them to organisms and ecosystem processes

Four main groups of freshwater organisms are known to produce sounds: amphibians, crustaceans, fish and insects. However, it is rare that researchers can visually identify the source of different sounds in underwater environments. Lowering a hydrophone beneath the water’s surface can be a surprising and disconcerting experience: the listener becomes immersed in the invisible soundworlds created by aquatic life. How might such soundscapes be translated into useful ecological metrics?

The editors highlight the need for more comprehensive catalogues of the sounds of freshwater life, which could offer researchers ‘reference recordings’ to compare to their own studies. In this issue, two studies develop such ‘soundtype references’ in Costa Rica and Northern Australia.

Underwater recordings of Cantarana Swamp, Costa Rica made by Ben Gottesman and colleagues.

2. Improving automatic sound detection and analysis techniques

In addition to better identifying and cataloguing freshwater sounds, the editors highlight the need to improve how recordings are processed and analysed. Autonomous sound recorders have the potential to generate a lot of data, particularly if multiple recorders are used over an extended period.

Manual transcription of these recordings – whether through listening, or the use of visual spectrograms – is thus time-consuming. As such, automatic sound recognition technologies – which can identify organisms based on their sonic signatures – are needed.

In this special issue, two papers develop the basis of what editor Dr Gifford calls a “Shazam for fish” by documenting the calls of different species of piranhas in Peru, and the spawning calls of ‘love-sick’ burbot in northern Canada. Another study develops an automated detection algorithm for the underwater vocalisations of the spadefoot toad, whilst another uses a deep learning algorithm to acoustically detect the highly-endangered white-bellied heron in Bhutan.

3. Archiving and sharing freshwater acoustic data

As researchers make advances in identifying aquatic life through sound, it is important that their data is archived and shared amongst the global scientific community, the editors state. They write that, “While the Cornell Lab of Ornithology’s Macaulay Library contains some fish sounds (982, which represents 0.25% of all calls), these are mainly marine and from the 60s and 70s.”

Initiatives such as the Freshwater Information Platform are driving forward open-access sharing of datasets, and perhaps there is scope to develop their sound libraries in the future.

4. Understanding acoustic patterns across landscapes

The way that ecosystems and biodiversity vary across landscapes is called spatial heterogeneity by ecologists. Traditional ecological surveys account for spatial heterogeneity in their design, often by replicating study methods in different areas of a landscape.

The editors suggest that ecoacoustic methods have yet to adopt similar approaches. They suggest that this is due to the volume of data generated by ecoacoustic methods and the demands it places on computer analysis systems. In this issue, one paper uses a regular spaced set of hydrophones to show that acoustic activity of aquatic insects (Hempitera sp.) is higher in open water than vegetated areas.

5. Understanding acoustic patterns over time

Ecoacoustic methods offer researchers the potential to monitor ecosystems over long timescales, offering an insight into the diurnal and seasonal patterns of life that occur in them.

Two studies in the issue (here and here) highlight nightly aquatic insect activity patterns. The editors suggest that studies which seek to identify aquatic animals by their calls should focus on such times of day when activity is highest.

6. Making links between sound and ecological health

The end goal of all ecological assessments is to understand the ecological health and condition of a landscape. Whilst there are limits to the scope of this in freshwater environments (e.g. only 20% of fish are soniferous), the editors highlight three useful approaches.

First, changes in aquatic sound can indicate changes to the wider ecological community. Second, ecoacoustics can help us understand the effects of noise on aquatic ecosystems. Third, ecoacoustics could help the automatic detection of invasive species – such as the round goby – reaching an ecosystem.

Clearly, ecoacoustic techniques offer new opportunities for freshwater scientists and conservationists seeking to understand and protect aquatic ecosystems, and the wide-ranging and innovative studies in this special issue highlight their rich potential.

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Linke, S., Gifford, T., Desjonqueres, C., (2020) “Special Issue: Passive acoustics: a new addition to the freshwater monitoring toolbox”, Freshwater Biology, Volume 65, Issue 1

Microplastic pollution could inhibit stream ecosystem functioning

January 17, 2020
Microplastic fragments. Image: Wolfram Burner | Flickr Creative Commons

Could plastic pollution affect how a stream ecosystem functions? According to a newly published study, the answer is yes.

Plastic pollution is rapidly growing in visibility as one of the key environmental concerns of this ‘Anthropocene’ age. Researchers around the world are increasingly focusing their efforts on understanding the effects that plastics – and particularly microplastics – might have on aquatic ecosystems.

As yet, however, this work has been largely focused on seas and oceans. Whilst there is a growing body of research on the effects of plastic pollution on freshwater ecosystems, there are still many unanswered questions.

The new study, led by Naiara López-Rojo, shows that microplastic pollution may cause significant effects on how stream ecosystems function. The research team used microcosm experiments (essentially glass jars filled with stream water) to study how different concentrations of microplastic pollution affected the growth of caddisflies, and the rates at which they decomposed leaf litter.

Leaf litter decomposition is a vital component of many stream ecosystems. Leaf litter – the leaves that fall into a stream from surrounding vegetation – is a key energy source for many invertebrates at the heart of stream food webs. Its decomposition – accelerated by invertebrates such as caddisflies – helps release carbon and nutrients to the wider ecosystem.

Recent studies show that microplastics are being found even in remote sites, carried on atmospheric currents. How might their presence affect stream ecosystems?

Caddisfly survival and leaf litter decomposition decreased with increasing microplastic concentrations in the study. Image: Naiara López-Rojo et al (2020)

López-Rojo, from the University of the Basque Country, Spain, and colleagues, exposed caddisflies and leaf litter to different concentrations of microplastics in water. They found that microplastics were rapidly ingested into the bodies of the caddisflies – most likely through the ingestion of particles attached to leaf litter – and then excreted.

This finding is consistent with recent studies, such as that by Fred Windsor and colleagues in rivers in South Wales, UK, which show evidence of microplastic uptake by invertebrates.

López-Rojo and colleagues found that higher concentrations of microplastics caused increased caddisfly mortality – which increased 9-fold at the highest concentration. However, they found that altering microplastic concentrations did not significantly affect caddisfly growth.

The researchers observed that increasing the concentration of microplastics in the microcosms caused leaf litter decomposition rates by the caddisflies to decline.

A Sericostoma sp. caddisfly larvae. Image: Wlodzimierz | Wiki Creative Commons

The study, published in the journal Environmental Pollution, is short in length and based on a relatively small sample size (32 microcosms, observed over a number of weeks). So why are its findings significant?

First, it provides more evidence to show that microplastics can be rapidly ingested into the bodies of freshwater organisms, and thus potentially accumulate and move through the food web into larger animals. Second, it suggests that the functioning of stream ecosystems – in this case through the key process of leaf litter decomposition – could be inhibited by the presence of high concentrations of microplastics.

The authors highlight the need for better monitoring of microplastic pollution in stream ecosystems to understand the extent of the pressures it might exert. In particular, they suggest that more research is needed to understand how microplastic pollution might affect ecosystems already influenced by multiple contaminants and stressors.

What is clear is that microplastic pollution is a growing issue for freshwater conservation and policy. López-Rojo and colleagues’ study is likely to be only the latest advance in the ongoing scientific effort to document and unravel its effects on freshwater ecosystems.

López-Rojo, N. et al (2020, “Microplastics have lethal and sublethal effects on stream invertebrates and affect stream ecosystem functioning,” Environmental Pollution, Volume 259, April 2020, 113898

Top 19 posts of 2019

January 4, 2020
Braided channels on the Alpine river Lech. This year’s Freshwater Blogs have covered a diverse range of topics across policy, science, art and conservation. Image: Gregory Egger

In these first days of 2020, we look back over 2019 to collect 19 of our most popular posts of the year.

It’s been another good year for the Freshwater Blog, with our biggest audience yet. Thanks, as always, for reading. You can keep up to date with our posts, and add your voice to the debate, through our Twitter, Facebook and LinkedIn pages.

Happy 2020!

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

The arapaima, a fish native to the Amazon Basin, which can grow to over 3 metres in length. Image: Lynn Chan | Flickr Creative Commons

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

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

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Protecting and restoring Europe’s waters: the future of the Water Framework Directive (February)

Reflections on water. Image: M.G.N. – Marcel | Flickr Creative Commons

A new survey of European water experts suggests that whilst the Water Framework Directive – the keystone of European Union water policy – provides a strong basis for the conservation and restoration of aquatic environments, there are three key areas for improving its future implementation. These include: monitoring and assessment, management measures, and policy integration.

Writing in the journal Science of the Total Environment, the researchers – led by Laurence Carvalho at the Centre for Ecology and Hydrology  – evaluate the strengths and weaknesses of current WFD implementation, identify where innovation offers new opportunities for monitoring and management, and address potential interactions between the WFD and other policy frameworks. In so doing, they ask, “Is the WFD fit-for purpose after 18 years and what improvements should be made in future implementation or revision?” (read more).

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Global insect declines: 33% of aquatic species threatened with extinction (February)

68% of caddisfly species populations are declining: more than any other order of insects. Image: Katja Schulz | Flickr Creative Commons

Global insect biodiversity is in dramatic decline according to a new review of existing scientific evidence. Aquatic insects are particularly threatened, with mayfly, dragonfly, stonefly and caddisfly species all showing significant declines over recent years.

Population declines of terrestrial and aquatic insects – in 41% of all species – are roughly twice those estimated for other vertebrates (mammals, birds and amphibians – 22% of species). The total global mass of insects is falling by an average of 2.5% each year, the study suggests, with potentially severe impacts on ecosystems and their services – such as pollination – globally (read more).

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Microplastics from the 1950s found in London lake sediments (March)

Hampstead Pond No.1 in North London. Image: Paul Robertson | Flickr Creative Commons

Microplastics dating back to the 1950s have been found in a sediment core taken from the lake bed of Hampstead Pond No.1 in London, UK. Plastic pollution is frequently featured in the news as a contemporary, oceanic environmental problem. However, a new open-access study by Dr. Simon Turner from University College London and colleagues provides evidence of long-term plastic accumulation in urban freshwater environments.

Hampstead Pond No.1 is one of thirty ponds on Hampstead Heath in North London, dug in the 17th and 18th centuries as reservoirs. Other ponds on the Heath are open to outdoor swimmers, anglers and model boating enthusiasts. However, despite their location in a cherished area of urban green space, the new study demonstrates that the ponds have been receiving plastic pollution for more than 60 years (read more).

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Acoustic monitoring of freshwater ecosystems: Costa Rica study reveals diverse underwater soundscapes (April)

The study site – Cantanara Swamp at La Selva Biological Station in Costa Rica. Image: Ben Gottesman.

Freshwater ecosystems across the world are disproportionately threatened by human activity, causing ongoing losses of aquatic biodiversity globally. Many freshwater conservationists highlight the need for more comprehensive ecological monitoring and assessment programmes to better understand ecosystem changes, and to strengthen conservation initiatives accordingly.

An innovative new study seeks to address this need using an unusual approach: acoustic monitoring of freshwater soundscapes. Researchers from Purdue University, USA and Nanjing University of Science and Technology, China recorded the aquatic soundscape of a Neotropical freshwater swamp in Costa Rica for 23 days in 2015. They used special underwater microphones – known as hydrophones – to delve into the acoustic world of the freshwater wetland. They wanted to better understand how soundscape recording might enhance existing freshwater ecosystem monitoring and assessment initiatives (read more).

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The IPBES Global Assessment: five things we learnt about freshwater ecosystems (May)

The critically endangered Panamanian golden frog (Atelopus zeteki). More than 40% of global amphibian species are at risk of extinction. Image: Brian Gratwicke | Flickr Creative Commons

A landmark global report summarised earlier this week suggests that around 1 million animal and plant species are threatened with extinction. For many species, extinction could occur within decades. The global rate of species extinction is already at least tens to hundreds of times higher than the average rate over the past 10 million years and is accelerating, the report states. What does the IPBES Report tell us about the state of global freshwater environments? (read more).

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Europe’s aquatic ‘life support system’: good ecological condition correlates with ecosystem service provision (May)

Floodplains and wetlands are vital habitats for providing natural water purification and flood protection. Image: Quoc Viet | Creative Commons

European aquatic ecosystems can better provide vital services – such as water purification and flood protection – to humans when they are in good ecological condition, according to a new study. These findings highlight the need to protect and restore European waters, not only for the non-human lives they support, but also for the health and well-being of human communities.

Bruna Grizzetti and colleagues mapped European aquatic ecosystem services in relation to ecological conditions in rivers, lakes, groundwaters, coastal and transitional waters, floodplains, riparian areas and wetlands across the continent. They found that there was a strong correlation between the delivery of regulating and cultural ecosystem services and good ecological condition (read more).

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Europe’s largest dam removal project underway on the Sélune River in France (June)

Drilling the first hole in the 36-metre high Vezins Dam on the Sélune River. Image: Roberto Epple-ERN | WWF

Europe’s largest dam removal project so far took a significant step forward last week as the first breach was made in the 36-metre high Vezins Dam in Normandy, France. The dam, located on the Sélune River, was been scheduled for dismantling in 2017, along with another 15-metre high dam, La Roche-Qui-Boit.

The removal of the dams is designed to reconnect migration routes for fish such as the Atlantic Salmon and European Eel, and to improve water quality in the river and re-naturalise flows of sediment through the Sélune catchment. The story here is indicative of global trends: a recent study suggests that only around one-third of global rivers are free-flowing – with dam construction a key factor in fragmenting and regulating water flows (read more).

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Lakes in the long term (June)

Lake monitoring on Windermere in the Lake District, UK. Image: Stephen Thackeray

A guest blog by Dr. Stephen Thackeray, a lake ecologist at the Centre for Ecology & Hydrology.

A cold wind bites and stiffens fingers that deftly prepare the probe for its descent. Moments later the instrument slips through the surface and glides from well-lit to ever-darker waters, where it will gather important data on the living conditions experienced by the hidden life of the lake. This is a world unseen. A world of constant change, where warmth, light, nourishment and danger vary hugely in time and space. It is also a place of super-abundant life.

This event is the latest episode in a multi-decade scientific endeavour that has tracked the changing fortunes of some of England’s most iconic lakes in Cumbria; a landscape now endowed with UNESCO World Heritage Status. Data from this ongoing year-round research, initiated by the Freshwater Biological Association in the 1940s and continued by the Centre for Ecology & Hydrology since 1989, tells a story of long-term change in the physical, chemical and biological conditions of the lakes. In Windermere, it is a story of decades of nutrient enrichment caused by sewage inputs and agricultural run-off and, increasingly, a story of climate change (read more).

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Illegal trafficking of the European eel: the ‘world’s greatest wildlife crime’ (July)

Glass eels from the River Shannon estuary in Ireland. Image: European Eel Foundation

Recent evidence shows the increasing impact of illegal fishing and trafficking as a major factor in European eel declines. Whilst the export of European eels out of the European Union has been suspended since 2010, between 300 to 350 million eels – as much as 100 tonnes of fish – are illegally trafficked from Europe to Asia each year, according to EUROPOL. This figure accounts for around one-quarter of the total number of glass eels reaching the European coastline each year.

Where a glass eel might cost a euro to buy, a fully grown eel can be sold for ten times as much. This profit margin has led to an illegal trade in European eels estimated to be worth €3 billion each year. This trade has been called ‘the world’s greatest, yet least known, wildlife crime’ by the Sustainable Eel Group (read more).

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‘A beautiful underwater world awash with light’: Michel Roggo’s Freshwater Project (July)

Rotomairewhenua (Blue Lake), high up in New Zealand’s Southern Alps, is sacred to the Māori. The lake has the clearest freshwater ever reported. Image: © Michel Roggo / roggo.ch

Freshwater ecosystems are often key parts of our everyday landscapes: whether ponds, lakes, rivers, wetlands and canals that we might cross and pass by regularly. However, glimpsing the life that goes on below the surface of freshwaters can often be challenging, even to the most regular visitors.

Some creative artists have used film to shed a light on underwater lives, whilst others have used sound to ‘eavesdrop’ on their aural worlds. Since 2010, Swiss artist Michel Roggo has been using photography to explore and document global freshwater habitats through his Freshwater Project. Roggo’s work has taken him to more than 40 freshwater ecosystems across the world, each containing unique and unusual biodiversity and geology (read more).

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Toxic legacy of historical pollution hinders ecological recovery on urban rivers (August)

The River Taff in South Wales. Whilst salmon and otters are returning to this river – once highly polluted by industrial discharge – ‘legacy pollutants’ may be hampering its ecological recovery. Image: Judy Davies | Flickr Creative Commons

Toxic chemicals released in past decades could be impeding the ecological restoration and recovery of Britain’s urban rivers, according to a new study. ‘Legacy pollutants’ such as PCBs (Polychlorinated Biphenyls) and flame-retardant chemicals (PBDEs) from historical industrial discharge persist in river catchments, potentially disrupting aquatic food webs.

Fred Windsor, lead author of the new study, explained: “Despite major success in controlling sewage pollution in South Wales’ rivers over the last three decades, something appears to be holding back biological recovery.” Windsor, a doctoral student at Cardiff University, continued: “Our investigations show that persistent contaminants might be responsible as they still occur widely in invertebrates, particularly in urban river environments.” (read more).

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Check, clean, dry: how can canoers help control the spread of invasive species? (August)

Power washing canoes and kayaks after use can help remove fragments of invasive plant species and control their spread between water bodies. Image: Paul Jepson

A guest blog by Dr. Paul Jepson, Nature Recovery Lead at Ecosulis Ltd.

On a hot Saturday in June I rolled up at the UK’s National Water Sport Centre. The place was abuzz with cars, kayaks, club flags and paddle-carrying athletes chatting bucket starts, heats, duck tape and Nelos. Everyone was readying to race on a highly engineered stretch of freshwater. It looked and felt a world apart from my world of conservation science and policy. Yet walking along with my daughter to get her kayak weighed, I spied a Wildlife Trusts flag and two fellow conservationists raising awareness of biosecurity and invasive species.

Gemma Rose and Helen Carter-Emsell work for North Wales Wildlife Trust, and had made the 120 mile journey to Nottingham to promote good conservation practices among kayakers. Gemma explained that the River Dee, which rises in Snowdonia and flows into the sea near Chester on the Welsh / English border, is rich in native wildlife but also hugely popular with canoeists. The Trust has teamed up with British Canoeing and the GB Non-Native Species Secretariat to raise awareness among canoeists of invasive species and the damage they can do to aquatic systems (read more).

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Vivid and lively aquatic worlds: the art of Jacek Matysiak (September)

Salmon. Image: © Jacek Matysiak

We recently came across the work of illustrator and designer Jacek Matysiak, and were so impressed that we knew we wanted to share it with you. Jacek is based in Dublin, Ireland, and his work provides a unique window onto the natural world. We caught with him recently to find out more (read more).

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Bending the curve of freshwater biodiversity decline (September)

What are the most significant and pressing freshwater biodiversity research questions that, if answered, would improve our ability to understand the state of freshwater biodiversity and improve its management and restoration, now and in the future?

This is the question asked by researchers affiliated with the Alliance for Freshwater Life as part of a new ‘horizon scanning’ research project seeking to identify the big questions in freshwater science, policy and conservation (read more).

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Global Swimways: conserving migratory fish populations (October)

A salmon leaps Brooks Falls in Katmai National Park, Alaska. The Global Swimways project aims to map and protect migratory routes of such fish. Image: Christoph Strässler | Flickr Creative Commons

A new ‘Global Swimways’ project has been launched this month, aiming to apply the insights of the ‘flyway’ concept to global migratory fish conservation. As part of this project, scientists will create the first global map of fish migration routes, identifying migration hotspots or ‘swimways’ and develop a new tool that highlights presence of migration routes near existing or planned infrastructure.

“Since the 1930s, people have developed and utilised the concept of flyways for the conservation of birds. They realised that in a world of changing habitats and building threats, you need global cooperation. It has led to successful agreements such as the Ramsar convention and international policies for conservation of ecological hotspots,” says Dr. William Darwall, project lead of the Global Swimways project, and Head of the Freshwater Biodiversity Unit of IUCNs Global Species Programme (read more).

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Europe must put environmental concerns at the heart of Common Agricultural Policy reform, scientists say (November)

Arable fields in Southern England. Intensive farming supported by the Common Agricultural Policy is a key driver of biodiversity loss, according to recent statements by scientists. Image: Richard H Williams | Flickr Creative Commons

Environmental scientists across Europe are campaigning for the European Parliament to take action in response to ‘catastrophic declines’ of birds, mammals, reptiles, amphibians, and insects as a result of intensive agricultural practices across the continent.

Earlier this week a letter signed by 2,500 scientists was sent to the European Parliament arguing that the intensive agricultural practices encouraged by EU’s Common Agricultural Policy (CAP) significantly threaten the continent’s biodiversity. There is now “unequivocal scientific consensus” that intensive farming is a key cause of the decline of bird and insect populations documented across the continent in recent decades, the authors state (read more).

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Catchment geology and human activity influence photosynthesis in aquatic plants (November)

The Norfolk Broads. New research suggests that plants in environments such as this, where biocarbonate levels are high, have adapted to use it in photosynthesis. Image: Ian Hayhurst | Flickr Creative Commons

Like all plants, aquatic plants rely on carbon to photosynthesise. However, unlike in the open air, carbon dioxide (CO2) is not a reliable source of carbon underwater. CO2 doesn’t diffuse efficiently through the water column, and is rapidly depleted as a result. So, how do aquatic plants get the carbon they need to live and grow? And how does this shape the distribution of where different plants are found?

A major new study shows that many aquatic plants have evolved the ability to use inorganic carbon, largely bicarbonate derived from the weathering of rocks and soils, in photosynthesis. Writing in Science, Lars L. Iversen and colleagues show that around half of the 131 global submerged plant species they studied showed this bicarbonate adaptation (read more).

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Water Framework Directive declared ‘fit for purpose’ (December)

The upper reaches of the Danube River. The transboundary management of the Danube catchment by the International Commission for the Protection of the Danube River is a WFD ‘success story’. Image: Heinz Bunse | Flickr Creative Commons

European water policy continues to be ‘fit for purpose’ in protecting and restoring the continent’s rivers and lakes, according to a new review by the European Commission. Adopted in 2000, the Water Framework Directive (or WFD) is the European Union’s flagship water policy. It requires member states to guide their rivers, lakes, estuaries and groundwaters to ‘good ecological status’ through environmental policy and management, and prevent any future deterioration of status (read more).

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Thanks for reading, and a very happy 2020 to you! If you are in need of more freshwater stories, you can read our previous annual post round-ups for 2018, 2017 and 2016.

Water Framework Directive declared ‘fit for purpose’

December 17, 2019
The upper reaches of the Danube River. The transboundary management of the Danube catchment by the International Commission for the Protection of the Danube River is a WFD ‘success story’. Image: Heinz Bunse | Flickr Creative Commons

European water policy continues to be ‘fit for purpose’ in protecting and restoring the continent’s rivers and lakes, according to a new review by the European Commission. Adopted in 2000, the Water Framework Directive (or WFD) is the European Union’s flagship water policy. It requires member states to guide their rivers, lakes, estuaries and groundwaters to ‘good ecological status’ through environmental policy and management, and prevent any future deterioration of status.

The European Commission recently concluded a two-year ‘fitness check’ evaluation of the effectiveness of WFD in meeting its objectives, alongside that of its linked water policies, the Groundwater Directive, Environmental Quality Standards Directive, and the Floods Directive. The WFD is now 20 years old, and its third cycle of River Basin Management Plans will run from 2022-2027.

The Water Framework Directive fitness check

The report’s verdict is mixed. On one hand, it highlights that the WFD has been successful in setting a governance framework for integrated water management of more than 110,000 EU water bodies. Since its adoption, the WFD has prompted EU nations to slow down the deterioration of their water bodies, and to reduce chemical pollution. Its continental monitoring network has also led to a significant increase in knowledge of European aquatic ecosystems, the report highlights.

However, no substantial progress in improving the overall status of European water bodies has been made. The report outlines that the implementation of the WFD has been significantly delayed, and less than half of all European water bodies are in ‘good ecological status’, despite the original deadline set for reaching this target being 2015. The report states that this is “largely due to insufficient funding, slow implementation and insufficient integration of environmental objectives in sectoral policies, and not due to a deficiency in the legislation.”

Virginijus Sinkevičius, EU Commissioner for Environment, Oceans and Fisheries, said: “Our water legislation is strong and able to protect both water quality and quantity, also in view of the new challenges from climate change and emerging pollutants, such as microplastics and pharmaceuticals. But more than half of all European water bodies are not yet in good status, and the challenges for Member States are more than substantial. We now need to accelerate the implementation of what we have agreed. The momentum of the European Green Deal will allow us to make such a leap forward.”

Diffuse nutrient pollution from agriculture is a common stressor on freshwater ecosystems, potentially causing eutropic algal blooms. Image: Dana L. Brown | Flickr Creative Commons

Challenges for European water policy

Improving the good status of European water bodies doesn’t only depend on measures required by the WFD, but also those in other EU legislation such as the Nitrates Directive and the Urban Waste Water Treatment Directive. Crucially, it also relies on the integration of water policy goals into other areas such as agriculture, energy and transport. Water is such a vital resource, with numerous (and sometimes competing) types of uses and users across Europe. Attempting to guide industry and agriculture towards ‘water-friendly’ approaches remains a key challenge for European water policy.

The report suggests that insufficient national funding can hamper WFD implementation, stating that Member States often propose management measures based on their existing budgets and policies, rather than tailoring them to the scale and extent of the pressures affecting their water bodies. This can lead to insufficient action to address the multiple pressures affecting water bodies, and an over-reliance on “easy technological fixes” such as reducing point source pollution, whilst leaving diffuse pollution sources unaddressed, the report states.

The design of the WFD is a balancing act between allowing Member States to implement measures tailored to their local conditions, whilst at the same time ensuring harmonised water management across national borders. The report suggests that the transboundary nature of many water issues can stand in the way of enforcing the WFD and holding Member States accountable for the ambition of their own water policies.

The resulting variation in policy ambition and effectiveness across Member States is one of the three key deficiencies in European water policy identified by the report. The others are: a need to update the list of priority pollutant substances (a significant challenge given the number of new synthetic chemicals entering water bodies); and to better integrate knowledge on multiple stressor interactions, particularly in the Groundwater Directive and Environmental Quality Standards Directive. The report finds that the Floods Directive (for which management plans started in 2016) has improved several aspects of flood risk management in Europe, but that ongoing efforts are required to tailor its implementation to future climate change projections.

Scientific and public support for European water policy

The report is published in the wake of the European Environmental Agency’s State of the Environment 2020 report, which identifies the WFD as a key policy tool for tackling biodiversity loss across Europe. There is also support for strong European water policy from both scientists and the public. Last week, an open letter from over 5,500 scientists emphasised the value of the WFD, and the need to ‘step up’ its implementation to conserve and restore European freshwater ecosystems.

In March, over 375,000 people supported the NGO-led #ProtectWater campaign, which demands that the European Commission and EU governments improve the implementation and enforcement of the WFD. The #ProtectWater campaign encouraged citizens’ participation in the public consultation process of the newly published ‘fitness check’.

Andreas Baumüller, Head of Natural Resources at WWF’s European Policy Office and Chair of the Living Rivers Europe coalition, said:
“By signing off the Water Framework Directive as fit for purpose, the European Commission is standing shoulder to shoulder with the hundreds of thousands of European citizens, scientists and civil society groups who have all championed the WFD over the past two years.

“As the results point out, slow implementation is to blame for not having yet reached the WFD’s objectives. The Commission now needs to put its money where its mouth is. It must ensure that Member States submit ambitious plans and concrete actions to achieve the law’s objectives by 2027, and that this is supported by dedicated funding.”

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Read the Fitness Check of the Water Framework Directive and the Floods Directive online here.

Major new book surveys nature and culture along Alpine rivers

December 6, 2019
The Lech River in the Alps. Image: Gregory Egger

The vast Alps mountain range is sometimes described as the ‘water tower’ of Europe. This is because a significant proportion (some estimates say 40%) of the continent’s freshwaters originate from its slopes, supplying drinking water to millions of people.

A newly published book provides a comprehensive survey of the diversity, value and uniqueness of Alpine rivers, and the issues relating to their management and future. ‘Rivers of the Alps: Diversity in Nature and Culture’ is the result of a major collaborative effort involving 150 experts from six Alpine countries, led by editors Susanna Muhar, Andreas Muhar, Dominik Siegrist and Gregory Egger.

Over 34 thematic chapters, richly illustrated with images and maps, the book offers a history of Alpine rivers and their geomorphology, which has shaped a range of unique habitats for wildlife. The book then explores how people have settled and used Alpine river landscape over time, covering wide-ranging topics of flood protection, hydropower and transport alongside mythology, tourism and art. The challenges for environmental management that arise from the dynamic human-nature interactions in Alpine river catchments are then considered. Finally, portraits of the individual characteristics of 54 Alpine rivers are offered. Susanna Muhar says: “we as editors aim to contribute to a greater awareness regarding the unique nature and value of Alpine rivers as well as the ways in which they are endangered.”

The Alpine Isel River. Image: Wolfgang Retter

Alpine rivers: woven threads of nature and culture

The book is timely and important: Alpine landscapes are shaped by their rivers and streams, both physically and culturally, but their complex systems are vulnerable to environmental change. A number of large European rivers – including the Rhine, Rhône, Inn and Po – have headwaters in the Alps, carrying water across the continent to the North, Mediterranean, Adriatic and Black Seas. Alpine river valleys have long been locations of human settlement, with their waters used for drinking, washing and irrigation. In recent centuries, tourists have increasingly explored Alpine valleys, taking advantage of their clear waters for boating, fishing and swimming. Alpine rivers support a unique range of biodiversity. They provide habitat for a number of species, including fish, invertebrates, amphibians, reptiles, mammals and birds.

Dominik Siegrist says: “The Alps are in many ways connected to their rivers. The alpine spaces are formed by the rivers, and the streams and large rivers characterise the Alpine landscapes. In the mountains and valleys, fluvial landscapes are an element of beauty but also the cause of the destruction of infrastructures and settlements. They are a source of drinking water for entire countries. Rivers also donate energy in different ways – for those seeking relaxation as well as for running the turbines of hydropower plants.”

Andreas Muhar continues: “The rivers of the Alps play an important role for the rest of Europe: they provide water and hydropower way beyond the limits of the Alps. The development of human settlements and infrastructure widely followed the course of the rivers. Their valleys form important corridors for transport on the rivers themselves and on roads alongside them. Today’s multi-functional river landscapes require that we find the right balance between utilisation and conservation, as well as integrate demands from many different fields such as energy production, material extraction, flood protection, agriculture, settlement, industry and recreation.”

The Alps is the source of around 40% of Europe’s freshwater. Image: Book Authors (Hi-res version)

Multiple pressures on Alpine rivers

However, despite their importance, Alpine rivers are increasingly threatened by human activity. The effects of climate change are being strongly felt in the Alps. In the book’s introduction, Klement Tockner states that air temperatures in the Alps have risen by just under 2°C over the past 100 years – almost twice the global average. Climate warming is changing the pattern and extent of glacier melt in the Alps. In 1876, glaciers covered an area of 1,800km² in the Alps. Climate change has caused the glaciated area to shrink by 40% in Austria and 30% in Switzerland since then, Tockner outlines.

This is important because glacial melt is a key element of the Alpine water cycle. Changing melting patterns alter the amount and timing of river flows downstream, and with it the aquatic ecologies and human livelihoods that rely on them. Climate change models project ongoing increases in air temperature through the 21st Century, with a potential complete loss of Alpine glaciers by the end of the century. This could mean more droughts and low river flows in summer, and more winter flooding and landslides in river valleys in the future.

Alpine river flows are also increasingly altered by hydropower projects. Only a small number of Alpine rivers remain in a ‘near-natural’ free-flowing state because of a recent boom in small hydropower plant construction. The seeming ‘eco-friendly’ credentials of such low-carbon energy production schemes are potentially compromised by the negative effects hydropower can have on the health of the wider river ecosystem.

Umballfalls in Alpine East Tyrol, Austria. Image: Andreas Muhar

A collaborative resource to support environmental policy and management

These key issues, and how they might be managed and mitigated through environmental management and policy (such as the Alpine Convention), are central concerns of the book. Editor Gregory Egger explains: “Our book gives the first Alpine-wide overview of all essential topics in the context of rivers and river landscapes. Particular attention is paid to the presentation of the characteristics of Alpine rivers. The book is intended to address both experts and readers interested in nature.”

Susanna Muhar says: “We are facing global changes regarding climate, land use, food and energy production, urban agglomerations and many other challenges. Freshwater ecosystems, and the functions and services they provide, are increasingly affected by these changes. In light of such adversities, it is particularly crucial to preserve those rivers and floodplain corridors that are still dynamic and interconnected. Such systems buffer flood events, provide habitats for reproduction and refugia from disturbances and enable species movements to suitable habitats in other parts of the watershed, particularly in response to transforming environmental conditions such as rising temperatures or changing hydrological regimes.”

‘Rivers of the Alps: Diversity in Nature and Culture’ is the result of extensive interdisciplinary collaboration.

Project manager Kerstin Böck says: “The book is the result of a major geographic project and includes contributions of more than 150 experts from all over the Alpine space. Coordinating this large number of people was sometimes challenging and required patience and a bit of tenacity.

“Over 10,000 mails were exchanged from the start of the project until now, and it took a lot of discussions until the present concept was ready. However, the result speaks for itself and brings together expert knowledge on all the important issues relating to Alpine rivers.”


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Find out more and order the book online.

Catchment geology and human activity influence photosynthesis in aquatic plants

November 22, 2019
The Norfolk Broads. New research suggests that plants in environments such as this, where biocarbonate levels are high, have adapted to use it in photosynthesis. Image: Ian Hayhurst | Flickr Creative Commons

Like all plants, aquatic plants rely on carbon to photosynthesise. However, unlike in the open air, carbon dioxide (CO2 ) is not a reliable source of carbon underwater. CO2 doesn’t diffuse efficiently through the water column, and is rapidly depleted as a result. So, how do aquatic plants get the carbon they need to live and grow? And how does this shape the distribution of where different plants are found?

A major new study shows that many aquatic plants have evolved the ability to use inorganic carbon, largely bicarbonate derived from the weathering of rocks and soils, in photosynthesis. Writing in Science, Lars L. Iversen and colleagues show that around half of the 131 global submerged plant species they studied showed this bicarbonate adaptation.

The research team found that plant species with this trait were generally found in water bodies where bicarbonate concentration is high. In other words, where bicarbonate is widely leached from the weathering of soils and rocks (e.g. from limestone and dolomite), aquatic plants have adapted to use it in their life cycles. This is in contrast to terrestrial environments, where plant communities are largely determined by climate, rather than geology.

However, bicarbonate use is not ubiquitous in aquatic plants, for two reasons. First, using bicarbonate in photosynthesis is an active process, and requires energy to process. Second, photosynthesis rates at limiting concentrations of inorganic carbon are higher in plant species that use CO2. In short, bicarbonate dependence might limit photosynthesis rates in some environments.

Global relationship between bicarbonate concentration and the proportion of bicarbonate users in freshwater plants. See Fig 1 footnote for more detail. Image: Iversen et al (2019)

As a result, the research team found that where CO2 concentrations in a water body are high (and substantially above the air equilibrium) – as is often the case in streams – the benefits of bicarbonate use are reduced. They observed that bicarbonate traits in aquatic plants were rarer in such environments.

The broad trend identified in this groundbreaking new study is that where CO2 is limited in the water column – most often in lakes – aquatic plants have tended to adapt to use bicarbonate as a source of carbon in their life cycles. However, where CO2 is available, plants preferentially use it in photosynthesis, like their terrestrial counterparts do. Thus, bicarbonate use by plants is a response to carbon limitation in aquatic environments, and observed more often in lakes than streams.

The study highlights the extent to which catchment geology and weathering processes can shape the distribution of aquatic plants in lakes and streams. However, human activities such as deforestation and agriculture have the potential to alter biocarbonate concentrations in aquatic environments, with resulting effects on the plant species they support.

Steep gradients in bicarbonate concentrations and spatial separation in species distribution in the British Isles. See Fig 2 footnote for more detail. Image: Iversen et al (2019)

The authors suggest that increases in bicarbonate concentrations – for example, as the result of nitrate fertiliser leaching – will have particularly severe impacts on biocarbonate-poor lakes. In such ecosystems, they suggest that plant species composition will significantly alter, as tall, fast-growing bicarbonate users colonise and suppress smaller species adapted to CO2 use alone.

Elsewhere in the same Science issue, aquatic ecologists Rafael Marce and Biel Obrador highlight three key areas of significance in the new study. They write:

“[The study] paves the way for future studies of the impacts of global change on freshwater biodiversity and ecosystem functioning. It highlights the need to develop models for the dynamics of dissolved inorganic carbon in fresh waters that go beyond the mainstream focus on CO2 emissions to the atmosphere. And it constitutes a powerful example of integrative ecology across spatial and temporal scales and knowledge domains.”

The broad-scale, interdisciplinary scope of the new study by Iversen and colleagues reveals new biogeochemical mechanisms that helps us understand the patterns and processes of freshwater biodiversity, and potentially predict global changes that can inform biodiversity conservation planning.

Accordingly, Marce and Obrador suggest that the study strengthens the argument for developing better biogeochemical models of river networks. “Although it is challenging to integrate complex geochemical and biological interactions at large scales, such models paint a more precise picture of the freshwater carbon cycle and better inform multidisciplinary research on biodiversity conservation and Earth-system modelling,” they write.

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Iversen L.L. et al (2019) “Catchment properties and the photosynthetic trait composition of freshwater plant communities”, Science, Vol 366, Issue 6467, 878-881

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Fig 1 detail: (A) Proportion of bicarbonate-using species across 52 plant ecoregions. Gray areas indicate regions where information on bicarbonate use in local plants is not available. (B) Relationship between mean bicarbonate concentration in plant regions and frequency of bicarbonate users. The line represents the mean proportion of bicarbonate users. (C) Density plots of bicarbonate preferences for bicarbonate users (n = 57) and obligate CO2 users (n = 72). The central horizontal black lines represent the means, and the boxes indicate the 95% confidence intervals around the means.

Fig 2 detail: Distribution of two pondweed species with contrasting bicarbonate use in the British Isles. Potamogeton polygonifolius (obligate CO2 user; black triangles) is found in areas with lower bicarbonate concentrations than are present where Potamogeton crispus (bicarbonate user; white circles) is found. The top left inset shows the density distribution of the two species across bicarbonate concentrations. Bicarbonate concentrations are from the global bicarbonate map (fig. S2), and species data were extracted from the geo-referenced plant occurrences.

Europe must put environmental concerns at the heart of Common Agricultural Policy reform, scientists say

November 8, 2019
Arable fields in Southern England. Intensive farming supported by the Common Agricultural Policy is a key driver of biodiversity loss, according to recent statements by scientists. Image: Richard H Williams | Flickr Creative Commons

Environmental scientists across Europe are campaigning for the European Parliament to take action in response to ‘catastrophic declines’ of birds, mammals, reptiles, amphibians, and insects as a result of intensive agricultural practices across the continent.

Earlier this week a letter signed by 2,500 scientists was sent to the European Parliament arguing that the intensive agricultural practices encouraged by EU’s Common Agricultural Policy (CAP) significantly threaten the continent’s biodiversity. There is now “unequivocal scientific consensus” that intensive farming is a key cause of the decline of bird and insect populations documented across the continent in recent decades, the authors state.

The future of the post-2020 CAP – what space for the environment?

Their letter is timed to coincide with ongoing EU debates over the updates made to the next iteration of the CAP, post-2020. The CAP was designed to encourage maximum food production across the EU, which despite attempts to promote agri-environment schemes, has led to “green deserts of uninhabitable maximum-yield monocultures” across the continent, the authors state.

The letter is authored by members of six European biodiversity organisations: European Ornithologists Union; European Mammal Foundation; Societas Europaea Herpetologica; Societas Europaea Lepidopterologica; Butterfly Conservation Europe; and the European Bird Census Council.

They argue for significant policy change, stating that: “A reform of the CAP must deliver sustainable and diversified agriculture through spatially-targeted measures supporting smaller farms which carry out sustainable farming and maintain high nature value farmland.” The post-2020 CAP reform should include significant policy measures which promote biodiversity conservation and restoration in agricultural practices, such as extensive grazing of livestock, they argue.

Such CAP reforms could align the policy with global agreements such as the United Nations’ Sustainable Development Goals in tackling climate change and biodiversity loss, the authors suggest. They state that: “The EU must be a pioneer in responding to these challenges and the CAP must be part of that response rather than continuing being the cause of greater environmental degradation.”

Agriculture as a driver of freshwater ecosystem pressures

Intensive agriculture is a significant driver of freshwater biodiversity loss and habitat degradation in Europe. It causes a wide range of pressures on freshwater environments, including water abstraction, pollution, water course fragmentation and alteration and soil erosion.

The European Environmental Agency’s 2018 state of European waters report states that agricultural production is the major source of diffuse pollution (of fertilisers and pesticides), which affects around 38% of EU surface waters. As a result, freshwater conservation is a key consideration of any ‘environmental’ CAP reform, particularly in better aligning its implementation with the Water Framework Directive.

Honney bee (Apis mellifera) on oilseed rape flowers. Image: Gilles San Martin | Flickr Creative Commons

European scientists call for support for statement on environmental failings of CAP

Meanwhile, a group of environmental scientists based at European universities have released a statement outlining that CAP “continues to fail biodiversity, climate, soil, land degradation as well as socio-economic challenges especially in rural areas.” The statement, led by Dr. Guy Pe’er from the German Centre for Integrative Biodiversity Research in Leipzig, Germany, frames agriculture as a key driver of environmental degradation across Europe. Submitted for publication in the British Ecological Society’s People and Nature journal, the statement builds on a series of research projects, reports and workshops on the environmental impact of CAP.

The authors call for more scientists to become signatories to their statement, which offers ten action points to move CAP towards delivering sustainable food production, biodiversity conservation, and climate mitigation. A key action point is to use ecosystem services – such as climate change mitigation, and water conservation – as guiding principles for reformed CAP design. In so doing, harmful subsidies (such as Coupled Double Payments for intensive agricultural systems) should be phased out in favour of those which promote environmental health, such as High Nature Value farming systems.

Other action points outline the need for Member States set clear, adequate, measurable and time-bound targets in their strategic plans when fulfilling CAP objectives, and to support innovative methods of agri-environmental support. The authors suggest that a landscape-scale perspective should be adopted in CAP reform, to coordinate agri-environmental schemes between farming practices across larger areas and longer timescales than is currently common. The need for better indicators of success, alongside stronger and more regular environmental monitoring and enforcement is outlined.

Overall, the statement emphasises that there is a wealth of scientific knowledge, best-practice case studies and management decision support tools to guide an effective ‘environmental’ reform of the post-2020 CAP. However, it is important that the CAP update doesn’t allow Member States to choose ‘low-ambition’ implementation which marginalises environmental concerns. Like the letter from the six European biodiversity organisations, the scientists’ statement is clear that the present CAP is failing in its environmental obligations, and that significant reform is necessary to promote more sustainable futures.

You can add your signature to the statement here.

Climate warming is changing Arctic freshwater ecosystems

October 25, 2019
The Delta River in Alaska. Much of the river’s watershed consists of arctic tundra, which is at risk from climate warming. Image: Bureau of Land Management | Flickr Creative Commons

Biodiversity in arctic lakes, rivers and wetlands is increasingly threatened by climate warming, according to a report published earlier this year. It is suggested that warming is shrinking the extent of what can be considered ‘Arctic’ environments, and with it the range and diversity of aquatic species that they support.

The State of the Arctic Freshwater Biodiversity report was produced by the Circumpolar Biodiversity Monitoring Program Freshwater Group of the Arctic Council Conservation of Arctic Flora and Fauna (CAFF) Working Group. The report – the first of is kind – provides a synthesis of the state of knowledge about biodiversity in Arctic freshwater ecosystems, and its trends and trajectories.

Patterns of biodiversity vary across the Arctic, with temperature and connection to the mainland two key drivers of biodiversity. In other words, it is generally the coldest and most isolated Arctic islands that support the lowest freshwater biodiversity, and the warmest and most connected (often at lower latitudes) that support the highest biodiversity.

However, warming temperatures across the Arctic are shifting where cold-adapted species can survive. Long-term observations show increasing water temperatures and decreasing ice cover in freshwater ecosystems across many parts of the Arctic. A shift to warmer, wetter climates has the potential to significantly impact aquatic systems: altering the seasonality of water flows; increasing concentrations of dissolved organic matter, sediments, minerals and nutrients in water bodies; and opening up new regions to human settlement and development.

The Arctic Council has eight nation state members: Canada, the Kingdom of Denmark (Greenland), Finland, Iceland, Norway, the Russian Federation, Sweden and the United States (Alaska). The report considers ecosystems in the Arctic Circle, largely at the northern range of these states.

The report suggests that with continued climatic warming, the boundaries of the Arctic climatic zones are expected to shift northwards. In other words, the area of ‘Arctic’ environment in the polar region is expected to shrink.

Warmer water temperatures in Arctic rivers and lakes may increase overall biodiversity, as southern species expand their population range northward. However, specialist cold-adapted and tolerant species which currently occupy Arctic freshwaters are likely to be put at risk, both by their shrinking habitat, and by competition from non-native species.

Cold-adapted species such as the Arctic char are likely to be put at risk by climate warming in Arctic regions. Image: Christa Rohrbach | Flickr Creative Commons

The report suggests that cold-water endemic species unique to the Arctic, such as the Arctic char, are likely to suffer regional losses, or even local extinctions as a result.

For example, long-term monitoring records from Iceland indicate a declining abundance of Arctic char and increasing dominance of Atlantic salmon and brown trout since the 1980s. This shift has coincided with an increase in spring and autumn water temperatures, which are likely to affect that spawning and hatching cycles of the Arctic char.

Temperature increases are also predicted to cause more cyanobacteria blooms across Arctic freshwaters. Long-term data in the report shows that cyanobacteria blooms – some of which were toxic – were most abundant in Arctic lakes during the warmest years on record. As climate warming continues, such blooms are likely to become more abundant, potentially causing ecological and human health issues.

The research by the Circumpolar Biodiversity Monitoring Program Freshwater Group which underpins the report is designed to help establish a long-term monitoring environmental framework for Arctic freshwaters. This framework is intended to facilitate rapid detection of, and responses to, changes in Arctic water quality and aquatic biodiversity.

Monitoring of Arctic freshwaters is carried out through the identification of Focal Ecosystem Components. These are ‘indicator’ species – such as fish, invertebrates and plants – whose population dynamics can indicate shifts in the wider ecosystem.

The report suggests, however, that existing scientific monitoring is not sufficient to describe freshwater biodiversity in all Arctic ecoregions. This is often due to challenge and cost of monitoring vast and remote areas. The authors argue for the need for increased and better harmonised monitoring efforts across the Arctic to better understand and manage the changes to freshwater ecosystems in this unique region.

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Read The State of Arctic Freshwater Biodiversity report here.