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Top 10 posts of 2021

December 29, 2021
Wildflowers bloom on the banks of the Emscher River, Germany. Image: MERLIN

In these slow days between Christmas and New Year we continue our annual tradition of looking back at the year’s top posts. There are encouraging signs that crucial freshwater issues are being taken increasingly seriously in environmental policy and management, with innovative new approaches to conservation and restoration being implemented.

However, the picture is still troubling for freshwaters: with multiple stressors including climate change, habitat loss and pollution all contributing to significant declines in aquatic biodiversity globally. But, with the growth in collaborations between dedicated freshwater scientists, policy makers, environmental managers and public activists across the world we have reason to be hopeful that 2022 could be the year in which we ‘bend the curve‘ of aquatic biodiversity declines, and safeguard our rivers, lakes, ponds, streams and wetlands for future generations.

You can explore all of last year’s posts here.


Multiple stressors shape river ecosystems across Europe (January)

The River Douro in urban Porto, Portugal. Multiple stressors from human activities are significantly impacting European river ecosystems. Image: Terry Kearney | Flickr Creative Commons

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


Wetlands: Havens of Life (February)

Pelicans on Prespa Lakes. Image: Julian Hoffman

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


World’s ‘forgotten fishes’ in catastrophic decline (February)

Snorkelling in a river in Western Cape, South Africa. Image: Jeremy Shelton

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


Towards a freshwater ethic: lessons from Aldo Leopold for contemporary aquatic conservation (March)

Aldo Leopold on a trip to the Rio Gavilan watershed in Mexico’s northern Sierra Madre Occidental. It was here that some of his key ideas about land and water conservation were formed in the 1930s. Image: Pacific Southwest Forest Service, USDA | Flickr Creative Commons

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


‘Plastic is everywhere’: microplastics found in 1950s freshwater fish specimens (May)

Specimens of sand shiner fish in the Field Museum’s collections collected in 1972, 1953, and 1907. Image: Kate Golembiewski, Field Museum

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


Developing MEASURES for reconnecting migratory fish habitats in the Danube basin (May)

The Danube at Mitterhaufen, Austria. The MEASURES project aimed to restore ecological river corridors across the Danube basin. Image: MEASURES

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


IPCC Climate Change Report: Three Key Themes for Freshwaters (August)

Extreme events including floods and droughts are predicted to increase due to climate changes over coming decades. Image: IPCC

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


Rights of Rivers at the IUCN World Conservation Congress 2021 (September)

The Whanganui River in New Zealand, the first river to be granted ‘legal personhood’ rights in 2017. Image: Tim Proffitt-White | Flickr Creative Commons

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


Mainstreaming freshwater restoration in Europe through MERLIN (October)

Beaver reintroductions are restoring natural processes to the Torringen area of Sweden. Image: MERLIN

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


Bringing freshwater research and policy out from ‘beneath the water’s surface’ (December)

Freshwater biodiversity declines are often hidden from public and policy view. Image: Solvin Zankl

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


Thanks for reading, and a happy 2022 to you! If you are in need of more freshwater stories, you can read our previous annual post round-ups for 2020, 2019, 2018, 2017 and 2016.

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