In a week’s time, people across the globe will get together to celebrate the world’s rivers, and those who struggle to conserve and restore them. The International Day of Action for Rivers, held each year on the 14th March, is organised by the NGO International Rivers, and provides a focus for communities across the world to organise events celebrating their rivers, and highlighting the threats they face.
The International Day of Action for Rivers was originally adopted by the participants of the first International Meeting of People Affected by Dams, March 1997 in Curitiba, Brazil. Now a global event, the day is described by International Rivers as a focus to “raise our voices in unison against destructive water development projects, reclaim the health of our watersheds, and demand the equitable and sustainable management of our rivers.”
This year, there are many events to participate in across the world. In England, there is a volunteer day on the River Don in Sheffield supporting the Lower Don Valley Flood Defence Scheme through removing litter, debris and fly tipping from the river and its banks. In Germany, environmental artists will stage a ‘Flying Fish’ performance on the banks of the Elbe in Hamburg. In Russia, a lecture and masterclass on ‘How to know about river health’ will be held in Vladivostok.
In Iran, the Mountaineers Club of Qaemshahr will host a public visit to the Siahroud River for the purpose of identifying and documenting the river’s pollution. The Pakistan Fisherfolk Forum will host a 14-day campaign called the Sindh Peoples Caravan, a massive people’s assembly hosting thousands of people from fishing and peasant communities, civil society members, academia, government officials, media and other stakeholders, focused on the conservation of the Indus Delta. At Labrador in Canada, a ‘Snowmobile Ride for the Grand River’ will be held, bringing together communities and stakeholders around the Churchill (or ‘Grand’) River, which is threatened by the construction of hydropower plants.
As these selected examples show, the International Day of Action for Rivers gives communities around rivers across the world the forum to organise a wide variety of events, and to give their local environments a global focus. Rivers are self-evidently an inspiration and concern for diverse communities across the world, and next week’s events will help highlight their importance and threats.
Writing in response to ongoing global biodiversity loss, the biologist EO Wilson optimistically stated in his 1992 book The Diversity of Life that “Here is the means to end the great extinction spasm. The next century will, I believe, be the era of restoration in ecology.” His prediction has broadly come true: in the subsequent 25 years, ecological restoration has become a central goal for many environmental managers and policy makers across the world seeking to alleviate the impacts of decades, if not centuries, of human activity.
The forms that ecological restoration takes are increasingly informed and challenged by debates in ecology (e.g. non-equilibrium ecologies, state shifts and trophic cascades), social and cultural considerations (e.g. the appropriateness of ‘natural’ historical baselines, perceptual shifts to ‘living with’ environmental change), and ongoing climate changes (e.g. the imperative to ‘future-proof’ restored ecosystems with resilience to future climate shifts).
In freshwater systems, there are – as yet – few long-term studies of the ecological impacts of river restoration on aquatic biodiversity. Emerging research on multiple stressors (such as in the MARS project) demonstrates that the choosing restoration strategies is not a straightforward approach, as the removal of one stressor (e.g. fragmented flows) may cause alterations to the impact of others, either positively or negatively. New river restoration strategies are being implemented globally each year, and long-term studies on the successes and failures of existing restoration projects are thus extremely valuable resources.
In this context, a new study by researchers based in Germany and the USA examined the responses of fish communities to the restoration of the Lippe River in Germany over a 21 year period. The Lippe has been heavily modified by human activity since the early 1800s, with a largely reinforced and straightened channel and bed, highly fragmented flows as a result of numerous weirs, and the widespread destruction of its riparian and floodplain landscapes.
The research team analysed data collected for 4 years before, and 17 years after, restoration at Klostermersch, where two stretches totaling over 3km in length were restored in 1996 and 1997. Restoration involved reconnecting the river’s floodplain with the river, removing bank fixations, widening the river from 18 to 45 metres in width, building a series of small islands, introducing full trees as deadwood, and reintroducing ‘natural’ floodplain drainage systems. In essence, the Lippe River ecosystem was encouraged to become more diverse in structure and dynamic in process.
Writing in a newly published study in Conservation Biology, the research team’s results show that this restoration management has led to a doubling of both fish species richness (i.e. the number of species) and abundance (i.e. the total species population sizes). On restored sections the Lippe, fish abundance exhibited an initial overshoot, where population numbers increased rapidly, then declined at a similar rate, as their numbers exceeded the ecosystem’s carrying capacity.
Both fish abundance and richness broadly stabilised around seven years after restoration at more than double the pre-restoration levels. However, there was (and is) significant variation in both abundance and richness from one year to the next. There are two environmental management insights here: first, that fish communities may take at least seven years to recover post-restoration and; second, that ongoing monitoring strategies are necessary to assess the impact of restoration strategies, as single sampling efforts may be skewed by annual variations.
The research team examined different traits of the fish species in the study, to understand if they played a role in how fish responded to restoration. They found that life history and reproduction related traits were influential. Opportunistic, short-lived fish species whose females reached maturity quickly and had multiple spawning runs each year most strongly increased in abundance, as a result of their ability to rapidly colonise new habitats. Such small-bodied fishes typically live in the dynamic in-stream and floodplain habitats that the Lippe restoration measures addressed.
As a result, the research team argue that focusing on fish species traits may help aid our understanding of how their populations are likely to respond to restoration measures. By relating restoration outcomes to such species traits, there is the potential to draw broader insights for restoration measures in other biogeographic regions, they suggest.
Liam Marsh is an award-winning natural history and wildlife photographer based in the Blackdown hills of south Somerset in England. His photographs of aquatic life – both above and below the waterline – are creative, unusual, and often beautiful. We spoke to Liam to find out about his approaches to revealing freshwater worlds through photography.
Tell us about your work as a wildlife photographer: how did you get started, and what are you working on at the moment?
I have always loved photography, and as a process it encourages you spend more time examining the world around you. I’ve always found wildlife to be the perfect match for that approach. Photography has given met a set of tools with which to examine the many wonderful creatures that live around us. All of my images are a result of countless hours spent watching wildlife and getting to understand them. It’s something that I never grow tired of.
I really see my job as a way of discovering interesting subjects or behaviours, and then trying to capture them in a way that is both attractive and engaging to an audience. Hopefully through my images I can share some of the fascination and curiosity I feel when watching wildlife first hand.
For my latest project, I’m working on a short film about caddis fly larvae and how they go about constructing their protective casings underwater. Film is something relatively new to me but I’m really enjoying the ability to share stories in ways that photography can’t always achieve.
Your photography in and around freshwater is stunning: what draws you to focus on rivers and lakes?
Thank you. I absolutely love spending time on or around water. There is always so much life and activity to be found in our freshwaters. There are challenges when working close to water, certainly, but I find these are far outweighed by the potential for interesting images.
I’m fascinated by the idea of this entire world that goes on almost without our knowledge, just below the water’s surface. It’s a thrill being able to show somebody a creature that lives so close and yet they may never have seen before.
What are some of your favourite aquatic species and habitats to photograph? Are you ever surprised by what you can see through a highly magnified lens?
I am always amazed by what I see through my lens. It doesn’t even have to be a very high magnification; even seeing the close up details of a familiar subject can be captivating. It’s that sense of wonder that keeps me motivated and inspired to create new images.
A favourite species of mine has to be dippers. They are such an interesting bird to watch, whether it’s the way they move or interact with each other: they are always active. In particular I love their connection to the water, they are so well adapted to their environment and yet behave unlike any other bird.
I can’t say that I have a particular favourite when it comes to habitat, but certainly I love looking at my local area. I’m fortunate enough to have travelled abroad several times taking photographs but nothing really compares to home. There is something special about uncovering the secrets of wildlife that live in your local area.
It’s easy to be dismissive of our local fauna and flora, there is always some larger, more flashy species abroad. But I think that some of the challenge involved in finding and learning about our local wildlife means that the encounters we have feel extra special.
There’s two wonderful galleries of aquatic photographs on your website: Life in a Drop of Water, and Underwater Photography on the Tiverton Canal. Could you tell us a little about these projects, their processes, and what they’ve produced?
Both of these projects involved looking at the fresh water environments local to where I live in south Somerset. Using both still and moving image, the intention to was to try to show the sheer variety and complexity of life in these underwater habitats.
My most recent project ‘Life in a Drop of Water’ looks at the freshwater invertebrates that live in our streams and rivers. These species play a vital role in the health of our rivers and yet are so easily overlooked.
I collected samples from several local streams and brought the specimens back to my small studio. These are tiny subjects, measured in mm rather than cm, so it can be a slow fiddly process to photograph them. Being so small I was able to suspend them in droplets of water (hence the title), as they are unable to break the surface tension. From there I was able to set the lighting and composition for each photograph.
Ultimately the aim was to show how complex and beautiful the creatures are that exist in some of our smallest fresh water habitats. These streams are full of animals that each have their own captivating stories to tell.
So far I have had a very positive reaction from the local people who I’ve shown the photographs to. There is a genuine fascination that people have for these animals and as a photographer that’s encouraging.
Can underwater photography influence how we think about environmental conservation and management, do you think?
Yes I hope so. I feel enormously privileged to spend the time that I do watching and learning about these animals and habitats. I understand that is not time afforded to everyone.
It can be difficult to encourage people to take an interest in conservation, especially when much of what needs to be saved is difficult to see or understand. Hopefully by seeing the richness and beauty of the life that surrounds us, people will be able to value and preserve it.
And finally, tell us about a ‘dream’ freshwater habitat you’d like to shoot in the future.
It might seem odd but I would really like to do more work on the rivers that run through our towns and cities. It would be great to try to dispel this idea that wildlife is reserved for the countryside. I think sharing the life that inhabits our rivers is a great way to do this.
In my experience, people are interested in wildlife but don’t always realise how accessible it is. If I could, in some small way, help people to see the importance of our rivers and how they themselves can help to preserve them, that would be fantastic.
The North Water Polynya is a large area of open sea in Baffin Bay between Greenland and Canada. The area is the largest polynya – an area of sea that remains ice free year-round, though surrounded by sea ice – in the world, and is one of the most biologically productive marine habitats in the Arctic Ocean.
Ecosystems on the Greenland coastline of the North Water Polynya are transformed – both positively and negatively – by nutrients brought back to land from the open sea by a tiny ‘ecosystem engineer’ bird, the little auk, according to a new study.
An estimated 30 million pairs of little auk travel to the North Water Polynya to breed each summer. At sea, they feed on nutrient-rich crustaceans called copepods. When they reach their breeding colonies on Greenland, the nutrients are largely excreted onto the land as guano.
The impacts on the ‘fertilised’ Greenlandic landscape are significant. Areas of land outside bird colonies are largely barren with little vegetation, as is common in environments at 76º North. However, areas within bird colonies have lush vegetation and large numbers of grazing animals such as muskox and geese.
“Our study found that the little auk acts as an ecosystem engineer across a large area of North-West Greenland. The colonies stretch over a 400 km range and up to 10 km inland so a very large area is affected. This creates highly productive oases in an otherwise rather barren landscape” says researcher Thomas Davidson from Aarhus University, a co-author of the new study, published in Proceedings of the Royal Society B, which also involved MARS aquatic scientist Erik Jeppesen.
The research team undertook analyses of stable isotopes of carbon and nitrogen in the coastal Greenland environment to track the flow of the marine-derived nutrients from sea to land. The research involved limnology, aquatic ecology, isotope biochemistry and bird tracking methods, and is part of the interdisciplinary NOW-project with anthropologists, archaeologists and local Inuit hunters.
Freshwater ecosystems, on the other hand, were negatively affected by the little auk’s ecosystem engineering. The bird’s guano is very high in nitrogen which, in addition to acting as a fertiliser, can cause the acidification of freshwater. One Greenlandic lake close to a colony had a water pH 3.4, which is more acidic than acid rain.
As a result, lakes and rivers affected by little auk colonies can support few invertebrates and no fish. As there are few grazing aquatic organisms able to survive in the acidic conditions, the nutrient-rich lakes are often green and eutrophic. The presence of little auk colonies is therefore a significant stressor on Greenlandic lakes and rivers.
This reduction in freshwater biodiversity caused by little auk colonies is opposite to the efffect of similar transfers of marine nutrients by migrating Pacific salmon. Numerous studies have shown that migrating salmon significantly increase biodiversity and ecosystem productivity in their spawning rivers in North America and Asia, both through their post-spawning decomposition and as prey to predators like bears.
Thomas Davidson summarises the study, “On a broad scale we sampled over 30 locations, both with and without bird colonies along the 400km coastline of the North Water Polynya, from Savissivik in the south to Siorapaluk in the north and demonstrated that both aquatic and terrestrial productivity is much higher in bird colony areas. We found that at least 85% of off all terrestrial and aquatic biomass was fuelled by nutrients brought to land by the little auk.”
Climate change may alter the ecosystem dynamics of coastal Greenland in the future. During the breeding season, little auks depend on nutrient-rich copepod species which live in cold sea waters. It is predicted that little auk populations will decline in response to the ongoing warming of the Arctic. If the little auk population declines, a significant shift in the Greenlandic coastal landscape around the North Water Polynya is likely to result.
Whilst this may mean less productive terrestrial ecosystems, it could be that lakes and rivers become less acidic, and become more habitable for aquatic life. However, a new stressor – climate change – will likely have significant effects on Greenlandic freshwater ecosystems as the effects of the little auks recede.
The new study sheds new light on interactions between marine, terrestrial and aquatic ecosystems in the Arctic, and reminds us that the impacts of future climate change are likely to be distributed in potentially unpredictable and surprising ways across inter-connected environments.
Largest freshwater Mediterranean lake may dry out in this century due to climate change and abstraction
Freshwater systems in the Mediterranean region are on the front line of climate change impacts in Europe. Future climate projections for the region indicate increasing air temperatures and decreasing precipitation rates through the 21st century.
Whilst fluctuations in water level and flow are a natural feature of freshwaters in the region, climate change is predicted to cause dramatic reductions in river flows and lake levels, causing severe water scarcity issues for the humans and non-humans that rely on them.
A new study suggests that if water abstraction rates from the region’s largest lake – Lake Beyşehir in Turkey – are not reduced, the lake will dry out in this century, potentially as early as the 2040s. The research, led by Tuba Bucak as part of the EU MARS and REFRESH projects, simulated the impact of future climate and land use changes on water levels in the lake.
Their models predict that increased temperatures and reduced rainfall coupled with ongoing water abstraction for agricultural irrigation place Lake Beyşehir at severe risk of drying out. If water abstraction rates are not reduced, the lake ecosystem and its rich biodiversity is likely to be significantly impacted (or even lost), and the human communities who rely on the lake for water and sustenance will lose the services and benefits the ecosystem provides.
All climate change scenarios (which used Representative Concentration Pathways) predicted a significant decreases in total water runoff into the lake (as a result of decreased rainfall), but the timescale of the decrease varied between the models. In comparison, simulated changes in land use had a minor impact on total runoff.
The decrease in water runoff common to each climate change scenario was projected to be more pronounced after the 2070s due to reduced precipitation and enhanced potential evapo-transpiration in the catchment. However, in one climate scenario modeled by the researchers, the lake was predicted to dry out completely by the 2040s.
The researchers write that despite the variance in their modelling results, that “a 9–60% reduction in outflow withdrawal was needed to prevent the lake from drying out by the end of this century.” In a water-scarce region, it would seem a challenging task for environmental managers and politicians to guide such a drastic change in water use.
However, there are precedents for similar large lakes to dry out. One Turkish lake, Lake Akşehir, has completely dried up in recent years, resulting in the extinction of the Central Anatolian Bleak. Two other endemic fish species, the Eber Gudgeon and a local dace (Leuciscus anatolicus) are now critically endangered.
For Tuba Bucak, lead author of the study, water management in the region needs to undergo a significant shift if Lake Beyşehir is to be protected. She says,
“Mediterranean lakes may face a risk of drying out and losing their ecosystem service values in future if essential mitigating measures will not be taken into account. We need to implement adapting measures (eg. reducing water needs by promoting drought resistant crops and efficient irrigation technologies) for maintaining water sources in Mediterranean and ensure sustainable water usage in order to meet the future water demands.”
Urban rivers across Europe are subject to multiple stresses linked to the surrounding built environment, particularly pollution, fragmentation, barriers and habitat modification. However, increased focus on the many benefits of urban nature, coupled with the imperatives in the EU Water Framework Directive to improve such ‘heavily modified water bodies’ to ‘good ecological potential’ mean that urban river restoration projects are proliferating.
The rivers Brun and Calder meet in the town of Burnley, in North-West England, and are part of the wider Ribble catchment. Flowing through an urban landscape which has supported industrial activity for centuries, the Brun and Calder have both been heavily modified and impacted by humans. Long stretches of the rivers are enclosed by stone and concrete channels, and in some places the river beds are made up of the same cobblestones found paving old streets through the town.
A new video (which you can watch above) produced by The Ribble Rivers Trust documents the community-engaged habitat restoration of Burnley’s rivers undertaken through the Urban River Enhancement Scheme (URES).
The Ribble Rivers Trust is an environmental charity established in 1998 to protect and restore the rivers, streams and watercourses within the Ribble catchment and to raise public awareness of the value of local rivers and streams. The Trust was awarded over £600,000 by the Heritage Lottery Fund in 2013 to deliver the URES, which intends to improve the habitat quality and biodiversity of Burnley’s rivers, whilst engaging local communities through education and conservation programmes.
The video shows URES habitat improvement on Burnley’s rivers, removing litter and debris, uprooting invasive species such as Himalayan balsam, constructing fish passes on large weirs, and restructuring river beds to create semi-natural riffles and pools in place of the existing sewer-like channels. It shows the various ways in which local communities are consulted and engaged in this process, through school visits, environmental artworks and conservation action days.
Below is a podcast interview with MARS scientist Prof Steve Ormerod from Cardiff University, carried out on the banks of the River Brun. Steve – a Burnley native – gives us an insight into the ways in which urban nature, culture and heritage are entwined along the banks of Burnley’s rivers, and how such recent restoration projects have significantly improved their habitat quality and biodiversity.
Since the podcast was recorded, salmon parr have been found upstream of the town, an extremely encouraging sign that migratory salmon can now successfully navigate Burnley’s rivers to reach a wide area of upstream spawning grounds.