Skip to content

What does the future hold for European rivers and lakes?

March 15, 2019
turkey-2110201_1280

Lake Beyşehir, one of the study locations for future environmental storylines in the study. Image: Pixabay | Creative Commons

Can we predict what the future holds for European rivers and lakes? How might changes to socio-economic conditions alter future trajectories for the health and status of surface waters across the continent? These are the questions at the centre of a new study led by Leoni Mack, from the University of Duisburg-Essen in Germany.

Funded by the EU MARS project, Mack and colleagues developed computer models to project how European surface waters are likely be impacted by different climatic, land use, management and development trends in the future. Their results suggest that stronger environmental policy and management are needed to achieve good ecological status in European surface waters under future conditions.

However, if such measures are not implemented, the linked pressures of human activity and climate change are likely to cause ongoing reductions in ecological status across the continent. Their results suggest that the impacts of pressures across Europe are likely to be more severe in rivers than lakes.

Key pressures in the future are likely to be similar to today: nutrient inputs from agriculture, land use changes (e.g. riparian zone development), poorly managed water abstraction, and growing climate change effects (e.g. water temperature increases; changes to flood and drought patterns).

There is likely to be geographical variation in how these pressures affect freshwaters, the study suggests. In Continental and Atlantic regions of Europe, land use changes are likely to be the key driver of environmental pressures, whilst in Mediterranean regions, the effects of climate change are predicted to dominate. In more northerly Boreal regions, the combined impacts of land use and climate change are predicted to drive environmental pressures, reflecting a likely trend of agricultural activities shifting northward with a warming climate.

1-s2.0-S0048969719307491-ga1_lrg

Graphical abstract of the study showing: methods, map of study basins, and results (TN= nitrogen, TP = phosphorous, Chl-a= algae growth). Image: Mack et al 2019.

Three lake and four river basins were modelled in the study, representing a number of typical European environmental conditions and human pressures. Nitrogen, phosphorous and chlorophyll a (a proxy for algae growth) dynamics were modelled to two time horizons – 2030 and 2060. These dates were chosen to give a picture of how alterations to current environmental policy (e.g. the Water Framework Directive) could have short-term impacts in the next decade (2030), and how climate change effects might be experienced over a longer term (2060).

Three storylines describing land use, management and development were assessed: ‘Consensus’, ‘Techno’, and ‘Fragmented’. Each storyline describes possible political, economic and cultural trends which to different combinations of drivers and pressures across Europe, using Shared Socio-Economic Pathway projections of socio-economic trends and IPCC Representative Concentration Pathway projections of climate change. The storylines are thus broad-brush forecasts of possible future trends across the continent, developed to help guide environmental policy and management decisions.

In Consensus World, future development in Europe follows similar patterns to the recent past, and environmental conservation and policy is supported. The world tends towards being relatively politically stable (Shared Socio-Economic Pathway 2), alongside a stablising and relatively low level of climatic change (Representative Concentration Pathway 4.5).

In Techno World, economic growth is strong, led by technological innovation, and human resource consumption is high. Ecosystems are valued largely for the benefits they provide to humans, and environmental protections are gradually rolled back over time in favour of promoting economic growth. High greenhouse gas emissions and rising global temperatures (Representative Concentration Pathway 8.5) are present, and there is a strong, carbon-based global economy (Shared Socio-Economic Pathway 5).

Fragmented World envisions a future with rising carbon emissions and significant climatic change (Representative Concentration Pathway 8.5). Technological developments are slow, and fossil fuel dependence is high; international cooperation is poor and significant pockets of poverty persist (Shared Socio-Economic Pathway 3). There is poor trans-national co-operation on environmental protections. Current environmental policy commitments are not met, or rolled back over time.

The authors highlight that different management approaches could have positive ecological impacts in each storyline. In Consensus World, present-day measures such as riparian shading had a positive impact on ecological status, whilst in Techno World, technological improvements such as increasing wastewater treatment efficiency were predicted to be key. In Fragmented World, agricultural extensification (i.e. the reduction in fertilisers and pesticide use per land area) was highlighted as a means of reducing nutrient pollution and habitat change.

The study, published in Science of the Total Environment, is rich in detail of how these potential political, economic, climatic and environmental trajectories might interact with freshwater ecosystems in the future. Overall, the results highlight the need for continued high ambitions for freshwater policy and management, and the political and public will to implement it for decades to come. The study emphasises the need for locally-appropriate targeted freshwater management measures to mitigate the effects of environmental pressures, whichever storyline(s) might develop in the future.

Mack, L et al (2019), “The future depends on what we do today – Projecting Europe’s surface water quality into three different future scenarios”, Science of The Total Environment, Volume 668, 10 June 2019, Pages 470-484

 

Microplastics from the 1950s found in London lake sediments

March 1, 2019
Hampstead Pond No.1 in North London.

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.

Plastic in UK lakes: a growing issue of concern

The impetus for the study, published in the Journal of Paleolimnology, arose from previous research carried out between 2008-2012 on other UK lakes. Dr. Turner explains, “At Edgbaston Lake, Birmingham we observed a lot of litter in the reed-filled margins but less in the deep water – and like some of the beach clean ups, some of the plastic waste, including crisp packets, drinks bottles, especially noticeable by their packaging design and best-before dates, had clearly been hanging around for a considerable period of time.

“What we realised was the amount and type of litter accumulating in lakes, especially plastic waste, had not really been assessed, especially when compared to marine habitats and simple questions like ‘how long has plastic been accumulating in lakes’ and ‘has plastic litter in lakes changed over time’ remained largely unanswered.”

In 2015, Rebecca Vaughan – at the time a UCL undergraduate – carried out a study of Edgbaston Lake to quantify just how much plastic waste was present in the lake sediment. Dr. Turner then built on this study to explore whether it was possible to identify microplastics (less than 5mm in diameter) in a dated lake sediment core. He and his research team chose an archived sediment core from Hampstead Pond No. 1, as it was accurately dated, large in volume, and surrounded by urban spaces which could provide sources of plastic pollutants.

As there is no long-term monitoring of plastic waste, such historical cores can provide a picture of plastic pollution through time. Plastics generally degrade very slowly –  a process which has been estimated to take hundreds of years – and so are likely to have built up in sediments in many freshwater environments. However, historical lake sediment cores had not been analysed for plastic pollutants prior to this study.

freshwatermicroplastics

Selected microplastic particles and fibres found in HAMP1 sediment core from Hampstead Pond No.1. Image: Turner et al (2019)

Microplastics in Hampstead Pond No.1

Dr. Turner and colleagues found a range of microplastic fibres and fragments in the Hampstead Pond No.1 sediment core. The fibres – of varying colours – are likely to be derived from the breakdown of synthetic textiles, and released into the lake from wastewater and sewage (although these inputs are relatively low in the pond), or via clothing, textiles, swimwear or fishing line. Microplastic fragments in the core were all orange foam polystyrene particles, ranging from 0.2–2mm in size.

Whilst there are some fibres in the core which may date from the late 19th and early 20th centuries, the majority of the microplastics found in the study date from the 1950s onwards. The accumulation rate of microplastics in the lake sediment was at its highest in the decade before 2009, when the core was taken.

Dr. Turner explains, “Like other contaminants released into aquatic systems, the composition and abundance of microplastics looks to have varied over time, as a result of changing industrial and domestic sources. We only have really started to quantify the inputs, transport and burial processes of microplastics in lakes, but this paper and others similar, are a step in understanding the global movement and accumulation of plastic waste in aquatic systems.”

hampsteadpondno1night

Reflections from neighbouring houses on Hampstead Pond No.1 after dark. Image: Chris Guy | Flickr Creative Commons

Microplastics and freshwater conservation

Microplastics can be ingested by freshwater organisms, as this recent paper by Dr. Fred Windsor and colleagues shows, potentially leaching harmful contaminants and additives into their bodies, or altering their physiology. As a result, understanding the transmission of microplastics through freshwater food webs – and their subsequent burial in sediments or transport elsewhere – is a key topic for research.

Dr. Turner says, “To get low density microplastic waste into benthic sediments we have to have a mechanism for accumulation and sinking – be it biofouling or ingestion and burial with organisms. Considering how resilient to degradation plastics were designed to be, my thoughts are that once in a lake, microplastics probably go through quite a few organisms before ultimate burial.”

Microplastic research in freshwaters is a growing area of scientific interest, and this paper contributes significantly to the field by showing that historical patterns of plastic pollution can be found in lake bed sediment cores. Clearly, plastic pollution is a key – if under-communicated – topic for freshwater conservation and policy. As Dr. Turner puts it, “Plastic waste in the environment – it’s not all about the oceans.”

Read the journal article

Turner, S., Horton, A.A., Rose, N.L. et al. (2019) “A temporal sediment record of microplastics in an urban lake, London, UK”, J Paleolimnol. https://doi.org/10.1007/s10933-019-00071-7

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

February 15, 2019
42147134580_82a51c3fab_o

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.

“As insects comprise about two thirds of all terrestrial species on Earth, the trends confirm that the sixth major extinction event is profoundly impacting life forms on our planet,” say study authors Francisco Sánchez-Bayo and Kris Wyckhuys.

Writing in the journal Biological Conservation, the authors reviewed 73 historical scientific reports of long-term insect population dynamics from across the world. They selected studies which considered all species in a taxon (e.g. family or order) within a large area (i.e. a region or country), or smaller areas intensively studied for more than 10 years.

freshwater insect declines 2019


Percentage of insect species in decline or extinct in four aquatic orders. Graphic redrawn from Sánchez-Bayo and Wyckhuys (2019: Fig 3b)

Freshwater species

Four orders of freshwater insects are addressed in the paper: mayflies (Ephemeroptera), dragonflies and damselflies (Odonata), stoneflies (Plecoptera) and caddisflies (Trichoptera). As most freshwater insect species have relatively inflexible life cycles, which makes them particularly sensitive to environmental pressures, the authors say. As a result, insects are vulnerable to pressures such as flow alterations, habitat fragmentation, pollution and invasive species.

The study suggests that – like for vertebrates – declines of aquatic insects are higher than those of their terrestrial counterparts (see graphics above and below). The authors estimate that 33% of aquatic insects are threatened with extinction, compared to 28% of terrestrial taxa.

Habitat generalist’ aquatic insects – which can occupy a number of different habitats – have been particularly affected, with major losses in all four orders of insects in large river systems across Europe and North America. However, insect communities have generally remained stable – or shown lesser declines – in near-natural mountain streams and lakes.

freshwater insect declines and extinctions 2019


Annual species declines and extinction rate for four aquatic insect orders. Extinction rate denotes the percentage of species not observed in >50 years. Graphic redrawn from Sánchez-Bayo and Wyckhuys (2019: Table 1)

Drivers of insect decline

Dr Sánchez-Bayo and Dr Wyckhuys identify four key drivers of global insect population decline: habitat loss, pollution, biological factors and climate change. For aquatic species, they highlight pollution as the main driver of population declines. Common sources of aquatic pollution include fertilisers and synthetic agricultural fertilisers, sewage and landfill leaching from urban areas, and industrial chemicals from factories and mining sites. The authors highlight the damaging impact of pyrethroid, neonicotinoid and fipronil insecticides on aquatic insects, due to their acute and chronic toxicity in water bodies.

As insects are crucial parts of food webs from the tropics to the tundra, the authors suggest that urgent conservation and restoration schemes are necessary to safeguard their populations and the ecosystem services they support. In particular, they highlight the need to reduce the runoff and leaching of toxic chemicals – particularly from industrial agriculture – into water bodies, in order to support the persistence and re-colonisation of aquatic insect populations.

Speaking to ABC television in Australia, Dr Sanchez-Bayo said, “We are not alarmists, we are realists. We are experiencing the sixth mass extinction on Earth. If we destroy the basis of the ecosystem, which are the insects, then we destroy all the other animals that rely on them for a food source. It will collapse altogether and that’s why we think it’s not dramatic, it’s a reality.”

The authors state that immediate global conservation action is required, chiefly through rethinking, “current agricultural practices, in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically based practices.”

13393612819686


Spraying pesticides on a lettuce field in Arizona, USA. Pesticide pollution is one of the key pressures on aquatic insect populations, according to the new study. Image: Jeff Vanuga | Creative Commons Public Domain Files

What about the tropics? Geographic variations and data deficits

The study reveals the geographic variation in detailed, long-term insect research across the world. The majority of the 73 studies selected for this meta-analysis are located in Europe and the USA, with only a handful from Central America, Brazil, South Africa, China, Australia and New Zealand. In fact, the data for China and Australia refers to managed honey bees only.

Whilst this reflects the distribution of funding and support for long-term ecological monitoring, it also restricts the certainty of making broad statements about the global health and status of insect populations. The insect declines reported here are primarily from temperate, northern hemisphere ecosystems. This isn’t to underplay the significance of the dramatic trends reported in the paper, but instead to caution about drawing global trends from the reviewed studies.

If anything, this study suggests that in addition to conserving the populations we know about, there is significant work to be done in studying (and mostly likely, protecting) those for which there are currently data deficits. Such work is unlikely to provide any good news, according to Georgina Mace, who told the New Scientist recently that Sánchez-Bayo and Wyckhuys’s review could in fact underestimate the declines in insect populations across the tropics.

So, in short, the picture of global insect declines painted by Dr Sánchez-Bayo and Dr Wyckhuys is alarming, but may not show the full extent of global declines. What is clear is that insect conservation must become a key focus for environmental policy with immediate effect if species declines – both documented and undocumented – are to be halted.

F. Sánchez-Bayo, K.A.G. Wyckhuys, (2019), “Worldwide decline of the entomofauna: A review of its drivers”, Biological Conservation, 232, pp. 8-27

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

February 1, 2019
16557878867_2dc9294e3d_o

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.

The Water Framework Directive (or ‘WFD’) obliges European member states to monitor, protect and restore their aquatic ecosystems. Adopted in 2000, the key aim of the WFD is to guide all European surface and groundwaters to ‘good ecological status’ (originally by 2015, but with extensions up to 2027). Ecological status is calculated using assessments of biological (e.g. plant and animal communities), physico-chemical (e.g. water temperature and nutrient levels) and hydromorphological (e.g. water flows and connectivity) elements of individual water bodies.

Despite a coordinated Europe-wide effort in monitoring, conserving and restoring aquatic ecosystems since the WFD was adopted, a 2018 European Environment Agency report found that around 60% of European rivers and lakes still failed to reach ‘good’ ecological status. Clearly, the WFD’s goals are laudable, but challenging to achieve in practice.

Is the WFD fit for purpose?

The WFD is currently in the middle of the second six-year cycle of River Basin Management, and a formal evaluation review of its effectiveness is due in 2019. In this context, a large group of freshwater scientists (many supported by the EU FP7 MARS Project) have published an analysis of the future development needs of the WFD.

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?”

To address this question, the research team canvassed 95 European water experts – including researchers, practitioners and policy makers – using a questionnaire survey following ‘The Future of Water Management in Europe’ e-conference held in September 2017. The questionnaire – based on themes from the conference, and circulated to participants – solicited responses on the effectiveness of monitoring and assessment, management measures, and policy integration in the WFD. The results thus reflect the ongoing experiences of expert practitioners who closely engage with WFD implementation, and provide a valuable insight into the policy’s strengths and weaknesses.

Co-author Dr. Anne Lyche Solheim, a senior researcher at the Norwegian Institute for Water Research (NIVA), gives an overview of the results, “The most important areas of improvement in WFD implementation are to enhance the confidence in assessment of current status through more and smarter monitoring, including citizen science. High confidence in status assessments, together with correct linking to relevant pressures, are fundamental to derive the appropriate combination and amount of mitigation and restoration measures, and to convince other sectors that action is indeed needed.

“Furthermore, better dissemination of knowledge is needed about the interactions of multiple pressures, particularly that synergistic interactions, such as those found for combination of climate change and nutrient pollution, may require increasing mitigation efforts such as putting additional measures in place to reduce nutrients. Better communication to other sectors and to the public is also needed on the benefits of management measures, including nature-based solutions, for different sectors and for water users.

“To prevent the development of negative opinions that costly measures seem to have no effects for many years, water managers also need to highlight that the time needed for recovery can be long, sometimes several decades. Finally, better integration is needed between the WFD and other EU and national policies related to agriculture, energy production and floods.”

beysehir

MARS scientists assessing multiple stressors in Lake Beyeshir, Turkey. Image: METU Limnology Laboratory

Monitoring and assessment systems

The WFD requirement for comprehensive aquatic monitoring has catalysed significant advances in methods of ecological status assessment, particularly in terms of ‘intercalibrated’ methods which allow cross-comparison of status-class boundaries. The resulting detailed picture of the health and status of Europe’s rivers, lakes, groundwaters, coastal and transitional waters was seen by survey respondents as a key success of the WFD.

However, a weakness of current assessment methods was identified in their failing to identify links between pressures and their impacts on the ecosystem. This linkage is crucial in supporting effective environmental management, particularly under the DPSIR (Driver, Pressure, Impact, State, Response) framework adopted by the WFD.

Another identified weakness is the ‘overly strict’ criteria to define management success. The ‘one-out-all-out-principle’ used in assessment means that the lowest score of the  biological, physico-chemical and hyrdomorphological elements measured in a water body determines its overall ecological status. In practice, this can mean that where different biological elements are sensitive to the same stressors, then the uncertainty associated with each individual assessment can be compounded. Respondents suggested that this uncertainty could be mitigated by reporting progress on individual quality elements, or by providing pressure-specific (e.g. eutrophication, morphological pressures) ecological status assessments.

Opportunities were identified in innovative monitoring schemes, including satellite data for large-scale and real-time assessment of variables such as water-colour, cyanobacteria blooms and plant cover. There are several active projects in this area stemming from the ESA’s Copernicus programme. In addition, citizen science programme such as CEH’s ‘Bloomin Algae’ smartphone app were identified as providing greater coverage for water assessment, whilst also offering new forms of public engagement. Finally, technological advances in meta-barcoding, environmental DNA (eDNA), automated sensor technologies and drones all offer the potential to assess aquatic ecosystems in increasingly precise ways.

However, adopting any new monitoring approaches requires compatibility with existing national and continental methods and a scrutiny of cost-effectiveness, the study’s authors suggest. More broadly, it is noted that expert ecological knowledge in practitioners is needed to underpin any assessment schemes and apply them in effective management schemes.

7657040976_338ea8bf85_o

Multiple stressors along the Emscher River in Nordsternpark, a former mining site in Gelsenkirchen, Germany. Image: M. Knuth | Flickr Creative Commons

Improving water management measures

River Basin Management Planning in the WFD outlines a Program of Measures to encourage an improvement in ecological status across entire catchments, often through partnerships with other sectors such as agriculture and flood protection. Such measures are either ‘basic’ (i.e. administrative and regulatory tools, such as pollution control) or ‘supplementary’ (i.e. active ecosystem restoration, such as natural flood retention planning). However, the study’s authors state that currently only around 20% of planned basic WFD measures and 10% of supplementary measures have been completed so far for hydromorphological and diffuse pressures. There are similar implementation delays for water abstraction mitigation measures.

Across Europe, there is a long history of successfully tackling point-source nutrient pollution from industrial and urban wastewater. However, diffuse pollution from agriculture is still a common cause of  poor ecological status in water bodies. Accordingly, in the first cycle of the WFD, two-thirds of the RBMP areas reported that basic measures are insufficient to tackle diffuse nutrient pollution from agriculture. In addition, the study’s authors state that there are a number of neglected or underestimated areas for WFD management, including: environmental flows, water abstraction effects, and invasive species. In short, whilst the WFD has helped support significant conservation and restoration efforts across Europe, there remains significant room for improvement and investment.

The study’s authors suggest three key areas that might improve WFD measures in the future. First, they highlight the need to manage for multiple stressors. Most WFD assessment methods are responsive to single stressors (e.g. nutrient loading), but at least 40% of European waters are subject to multiple stressors (e.g. nutrient loading and temperature increases), with potentially complex interactions and impacts. Whilst there is currently limited evidence on the impact of multiple stressors on aquatic ecosystems, there are a number of emerging scientific studies which highlight how stressor combinations can impact specific water bodies in different places (much of which has stemmed from the EU MARS project). The authors thus emphasise that restoration measures should be based on up-to-date understandings of this emerging literature, in order to account for the complexity of real-world environments.

Second, Carvalho and colleagues highlight the need for improved diagnoses of the causes of deterioration in ecological status. Much like a doctor’s diagnosis, tools are needed to assess the potential causes of deterioration (stressors) from a range of symptoms (biological metrics) of a water body, in order to ‘prescribe’ appropriate management measures. Here, the potential of combining Biological Quality Element assessments with other survey data, and to use new diagnostic tools (such as the MARS cookbook) and targeted monitoring were highlighted by survey respondents.

Third, the authors suggest that the incorporation of an ecosystem service framework can strengthen water management. This is not a new idea, by any means, and ecosystem services are already adopted in RBMPs in some EU countries. An emerging opportunity in this area, however, is in the potential to monitor and assess changes in ecosystem service provision in response to water management measures. In short, if it can be quantitatively shown that healthy and biodiverse aquatic ecosystems provide more ecosystem services to humans, then the argument for their protection and restoration is likely to be significantly strengthened.

14469992045_99f9eb2b88_k

A tractor sprays an apple orchard. Image: Barbara Eckstein | Flickr Creative Commons

Integration across policy sectors

Water is a key part of our daily lives, and as a result is a key aspect of numerous different national, EU and global policies across a wide range of sectors. At the river basin scale, the implementation of the WFD involves significant efforts to engage other administrative sectors, stakeholders and the public in planning and management. As a result, managing water necessitates collaboration: a task which is an ongoing challenge for WFD implementation, the study’s authors suggest.

The survey results outline a perception that water policy needs to be better integrated with other policy areas, such as agriculture, flooding, climate and energy, in order to be successful. This is not a new topic of concern, and was highlighted in the 2018 EEA assessment of European aquatic ecosystems. Agriculture is highlighted as the most important sector to make ‘water friendly’, which is unsurprising given the environmental issues such as soil erosion, water abstraction, nutrient and pesticide pollution and riparian alterations it causes across Europe. The authors outline a key tension between the aims of the Common Agricultural Policy – primarily food production – and WFD objectives, which has created a barrier to collaborative developments, they argue.

One approach to addressing this tension is ‘sustainable intensification’, where best practices in land management focus on achieving higher yields with reduced resource (water, fertiliser, pesticides) use, such as in the Baltic Deal Project. However, this balancing act between agricultural yield and environmental impact is not easy to undertake, and as the study’s authors suggest requires the production of, “more formal guidance on the difficult boundaries between regulating polluting acts, requiring the polluter to pay and paying not to pollute. This is linked to questions over who pays for the environment and the resource costs of water services, but extends far beyond the WFD to other aspects of land use and land management.”

Symbolique 2006

The WFD is the keystone of European water policy. Image: Symbolique 2006

Summing up and looking forward

The authors conclude by stating that whilst this expert analysis of the gaps, challenges and opportunities in the WFD is vital, it is important not to lose sight of the successful policy framework and momentum the WFD has created since 2000. They highlight that its focus on ecological status is better accepted in contemporary policy, and aligns the WFD with the EU Biodiversity Strategy 2020, and the global goals of the UN Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES). Similarly, the protection of water quality and aquatic ecosystems are key parts of the UN Sustainable Development Goals set in 2015 (Goal 6 and Goal 14).

In short, the key to improving the effectiveness of the WFD towards its 2027 target is not one of policy design, but of implementation, the authors suggest. Progress with management measures, and resulting improvements to ecological status, in European waters have been slower than initially anticipated. However, by addressing the areas of improvement highlighted in this study through a long-term integrated water management perspective which accounts for a dynamic world, Carvalho and colleagues conclude on an optimistic note that “real progress can be made” in the future.

Carvalho L. et al (2019), Protecting and restoring Europe’s waters: An analysis of the future development needs of the Water Framework Directive, Science of The Total Environment, Volume 658, pp 1228-1238

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

January 14, 2019
arapaima

The arapaima, a fish native to the Amazon Basin which can grow to over three 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.

Arapaima habitats change in depending on water levels, and these freshwater giants can become trapped in small floodplain lakes during the dry season. However, their ability to breathe air using a specially-adapted swim-bladder allows the arapaima to survive, even in such low-dissolved oxygen environments. As a result, the arapaima must periodically rise to the surface, which makes it vulnerable to fishing pressures. However, scientists do not have enough data on the health and distribution of arapaima populations to accurately assess their conservation status.

The arapaima is an important cultural animal for local communities in the Amazon and Essequibo basins, whether as a foodstuff, source of medicine (its tongue) and clothing (its skin); or as the inspiration for stories and folktales. As a result, there is increasing interest in community-based approaches for conserving arapaima populations.

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.

+++

Paul Jepson: Congratulations on your prize. This year’s topic was biodiversity conservation and social transformation. What do you think it was about your research that impressed the judges?

Joao Vitor Campos-Silva: Brazil, like many countries is searching for new models and paradigms to reconcile nature conservation and development. My research assessed the ecological and quality-of-life outcomes of two large community based-management initiatives in the Amazon linked to arapaima and freshwater turtles.

Scientific research often seems to provide yet more evidence of declines, however based on long-term participating monitoring data I was able to show that arapaima and freshwater turtle numbers have rebounded and the communities are flourishing. I think the judges liked the fact that I was telling a positive story of how a community had transformed the way they managed freshwater resources, and how the recovery of these resources is opening new community opportunities.

fig1_arapaima_fisherman_carlos_peres

The arapaima (Arapaima gigas) is the largest scaled freshwater fish on Earth. It evolved in the ancient Lake Pebas which had low oxygen concentrations. For this reason the arapaima evolved to be an air breather. It is nowadays restricted to the Amazon flood plain and reaches weights of 220 kg, although historical books report specimens up to 350kg. Image: Carlos Peres

PJ: Tell us more about the community whose management you researched and the arapaima. What is the ‘communities approach’ to arapaima management and how did it come about?

JC-S: The arapaima is an awesome fish – it is like a monster and people are very curious about it. People from outside Amazonia wonder how it can be caught. Among the Amazon people it has huge cultural importance: one origin myth believes that people and arapaima came from the same brothers! It seems to be something of an icon for everyone. During the 1970s fishing vessels from outside arrived to catch arapaima and freshwater turtles. As well as causing steep declines in the populations of these species, lots of other fish species were caught threatening the local community’s food security.

Community leaders in the Medio Jurua – the area I studied – heard about a community arapaima management approach being developed in the Mamirauá Sustainable Development Reserve, 2000 km away. Briefly, local fishermen in Mamirauá told a fishery scientist called Leandro Castello that they knew a way to count arapaima, and together they developed a robust survey method. At the time the government was establishing sustainable use reserves and promoting zonation approaches.

In the Medio Jurua region a social organisation had formed in response to the rubber tapper movement of the 1970s, and they helped communities to organize to zone lakes, agree catch rules and organized the sale of arapaima and other natural resources to external markets.

PJ: So how did you get involved in the area and what were your research motivations?

JC-S: I started to work at Jurua River 10 years ago. After completing my masters, I got a job with the government of Amazonas State to coordinate participatory monitoring initiatives in their sustainable use reserves. Through this role I got to know Prof Carlos Peres who is a leading Amazonia researcher based at the University of East Anglia in the UK.

I saw that Jurua river was a bright spot in Amazon conservation, where the model of social organization offers hope and optimism for combining biodiversity protection with improvements in people’s local well-being. Prof Peres and I secured a Darwin Initiative grant and this enabled me to enroll for a PhD and make a comprehensive study.

peres_community_based_arapaima_management_carlos_peres

Arapaima on jetty. Arapaima are caught with nets and harpoons. The local social association has purchased a purpose-built boat with ice storage to transport arapiama to the city of Carauari from where they are transported by river to Manaus – a 10 days journey. Image: Carlos Peres.

PJ: Your 2016 paper in Scientific Reports demonstrated remarkable recoveries in arapaima populations as a result of management. Tell us about the scale of these recoveries and their impacts for the communities.

JC-S: In the paper I analysed eight years of participatory monitoring data. This showed a thirty-fold increase in arapaima numbers in protected lakes compared with unprotected lakes. The overall population growth was over 400% in eight years. In some lakes there were originally only 20 arapaima remaining, and now there are 2000 or more!

The protected lakes act like high-interest saving accounts for the people. The arapaima are harvested once a year and generate around €8,000 per managed lake. This income is divided among participating families who are then investing together in improving local social infrastructure such schools and health posts. Moreover, the lakes provide a source of social security, with local people able to draw on other fish resources according to their needs. Another thing to mention is that arapaima management is addressing historic gender inequalities in the communities – women are included in the decision-making, income generation and in planning the use of natural resources.

PJ: In your view, what was the key to the success of this community management approach, and are there aspects that can be replicated elsewhere?

JC-S: I think that this Jura model has some special ingredients, including culturally important species, clear economic returns, strong local knowledge and a willingness to respect both locally generated and Federal rules. The combination of collectively agreed spatial zoning with no-take areas and a strong social organization has ensured compliance among users. Most people see the benefits – in terms of their livelihoods and life-quality – of respecting the rules and collectively managing the fishery.

The challenge of course is to replicate this model at a large-scale across the Amazon Basin. Now we have 30 areas adopting a similar model, and involving more 400 communities. The big challenges are ensuring fairness around the fisheries. By this I mean that middlemen don’t capture too much of the value. We also need to put in place the infrastructure to transport the fish – they are big, there are a lot of them, and it’s a long way to markets in Manaus and other Brazilian states!

freshwater_turtle_priscila_miorando

The Giant South American Turtle can reach 90 cm in length and 75 kg in weight. Image: Priscilla Miorando

PJ: I understand you also researched community management of freshwater turtles. Tell us a little about that aspect?

JC-S: Alongside arapaima management the communities also started to protect freshwater turtles nesting on river beaches. The Giant South American Turtle (Podocnemis expansa) was also badly over-exploited but our research showed that community protection of beaches has induced a large-scale population recovery of this and other turtle species along a 1,500-km section of a major tributary of the Amazon River. We showed that egg collection happens in just 2% of nests on protected beaches, compared with 99% on unprotected beaches.

These activities have not yet generated economic returns. This is a problem because dissatisfaction is growing among community guards who get very little return for what can be dangerous work. Many are now on the brink of giving up and the long-term viability of this approach will require the development of revenue streams independent of the food support they receive from the government and NGO partners.

PJ: Your 2018 paper in Nature Sustainability talked about the ‘collateral benefits’ for other species of turtle protection. What were these?

JC-S: Beside the population recovery of the turtles we showed conservation benefits for a wide range of other species, including caimans, catfishes, river dolphin, green iguana, migratory birds and even invertebrates. The protected beaches become thronging and dynamic places of bio-abundance. A friend of mine, Karla Koehler, captured this difference in a nice sketch.

amazon protected beaches

Illustration of the ‘collatoral’ conservation benefits of protected beaches (left) versus no protection (right) in the Amazon Basin. Image: Karla Koehler

figura 3

A protected beach in the Amazon Basin. Image: Joao Vitor Campos-Silva

PJ: Traditionally Brazilian conservationists have adopted a protectionist approach to species conservation. Your research seems to show that sustainable use can work – do you think that attitudes are changing?

JC-S: Many older conservationists in Brazil believe that conservation and social outcomes are not possible in the same package. Sometimes I feel that phrases like ‘bottom-up’ and ‘community-based’ are assigned to initiatives that are in reality still top-down or externally managed. Many of these have failed and this may reinforce the perception that ecological recovery and community development are incompatible.

Community-based approaches are certainly not a panacea, but neither is it a naïve narrative. There are more than six million people in the Brazilian Amazon aspiring to basic improvements in their quality of life. By providing nature-based pathways to achieve this community-based resource management can counter the forces of deforestation and biodiversity loss. There is a younger generation of government officials who much more open to this way of thinking.

+++

Cited papers:

Campos-Silva, J. V., & Peres, C. A. (2016). Community-based management induces rapid recovery of a high-value tropical freshwater fishery. Scientific Reports, 6, 34745.

Campos-Silva, J. V., Hawes, J. E., Andrade, P. C., & Peres, C. A. (2018). Unintended multispecies co-benefits of an Amazonian community-based conservation programme. Nature Sustainability, 1(11), 650.

Top 18 posts of 2018

January 3, 2019
meander path

Micro-meander formed on a cycle path following a storm. Many of this year’s top posts have addressed increasingly complex human-nature entanglements in aquatic ecosystems. Image: Evelyn Berg | Flickr Creative Commons

As we tiptoe into 2019, we’ve looked back over 2018 to collect 18 of our most popular posts on freshwater science, policy and conservation.

It’s been a great year for the Freshwater Blog, with a record numbers of visitors. 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 2019!

+++

‘Modest’ fine sediment and phosphate pollution in English rivers causes mortality of up to 80% of mayfly eggs (January)

Serratella-ignita-f-03-fws

Blue-winged Olive. Image: Francisco Welter-Schultes | Wikipedia Creative Commons

Increased levels of fine suspended sediment and phosphate in aquatic ecosystems can have significant negative impacts on the survival of mayfly eggs, according to a new study. Relatively modest levels of pollution can kill up to 80% of eggs, with potentially devastating effects on mayfly populations and wider aquatic food webs.

Writing in the journal Environmental Pollution, a team of researchers led by Nick Everall of the Aquascience Consultancy carried out experiments on the blue-winged olive, a species of mayfly found across Europe, whose populations have fallen in recent decades. (read more)

+++

Messages from MARS (February)

after dark

The final MARS project conference in Brussels. Image: Jörg Strackbein

The EU FP7 MARS Project“Managing multiple stress for multiple benefits in aquatic ecosystems”celebrated its final conference in Brussels last month.

The event concluded four years of in-depth research by MARS scientists on multi-stressor effects on European surface and ground waters, highlighting the implications for Water Framework Directive (WFD) related management. Among the array of fascinating results generated by the MARS project, four key messages were reported at the conference. (read more)

+++

Managing multiple pressures from recreational activities on freshwater ecosystems (March)

33679380172_03960acb5d_k

Campsite beside a Swedish lake. Fuel and waste disposal can cause lake pollution. Image: Jörgen Brouwer

Rivers and lakes are popular places for people to relax, play and exercise, and recreational activities like boating, bathing and angling are all well-documented to have positive effects on human well-being. But can the enjoyment of such freshwater ‘ecosystem services’ cause pressures on aquatic ecosystems? And how best can recreational activities be managed to minimise the harm they might cause?

A review of available data on the topic recently published in the Environmental Reviews journal shows that environmental quality is closely liked to recreational activities in many freshwater ecosystems. The ecological health and diversity of a river or lake can be an attractive draw for visitors, potentially causing tensions between tourist ‘hotspots’ and areas of conservation importance. This means there is a pressing need for effective management strategies to minimise ecological damage from visitor use in many places. (read more)

+++

Visualising multiple stressors on European river catchments: the MARS Scenario Analysis Tool (March)

sat mars laptop

Over the last four years, the MARS project has been investigating the interactions and impacts of multiple stressors on Europe’s aquatic ecosystems. This is a topic at the cutting edge of freshwater science research, and MARS scientists have sought to understand how the multiple pressures humans place on the environment – nutrient pollution, habitat alteration, climate change, water abstraction, and many more – act together to cause stress on the continent’s rivers and lakes. As a result, this work is important for environmental managers and policy makers seeking effective options to mitigate multiple stresses, and conserve or restore Europe’s freshwaters.

MARS has recently launched its Scenario Analysis Tool – an online, open-source mapping tool, which allows users to visualise and analyse multiple stressor conditions in European rivers. The tool can generate maps showing where different stressors occur, how many stressors co-occur, and their potential impacts on ecosystem status, at both the river basin and the continental scale. (read more)

+++

The Water Framework Directive at 18: Future Directions and Emerging Challenges (May)

8034352414_886c1d50f3_k

Image: Jim Liestman | Flickr Creative Commons

The Water Framework Directive (WFD) is the foundation of European Union water policy. Adopted in 2000, the WFD provides a policy framework for European member states to monitor, assess and manage their aquatic ecosystems. However, despite widespread improvements in the monitoring, conservation and restoration of rivers and lakes across Europe, the WFD has not yet achieved its primary objective: the good ecological status of all European freshwaters.

A formal EU ‘fitness check’ evaluation of the WFD is due in Autumn 2019. Ahead of this assessment, MARS researchers have published a policy brief providing recommendations for the future implementation and evaluation of European water policy. They identify four key areas to be addressed. (read more)

+++

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

3_restored_river

Restored river section five years after restoration with riparian vegetation consisting of grasses, shrubs and trees. This riparian vegetation can effectively fulfill buffer functions and support riverine biodiversity. Photo: Christian K. Feld

Safeguarding the banks and margins of streams and rivers has a key role to play in ensuring river health. This is the major conclusion from a new international study recently published in Water Research.

The authors of the new study synthesised the findings of more than 100 river management studies, many of which addressed the effects of riparian restoration on riverine habitat and biological conditions. It is widely acknowledged that riparian plants provide food for aquatic organisms, and can mitigate water temperature increases under climate change. Riparian zones can also provide valuable ‘buffer zones’ for run-off from farming and urban areas, preventing pollutants from reaching the river channel. Yet such riparian effects are not to be taken for granted. (read more)

+++

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

Symbolique 2006

MARS has investigated how multiple stressors affect European rivers, lakes and groundwaters over the last four years. Image: Symbolique 2006

After four years of research on multiple stressor interactions and impacts in European aquatic ecosystems, the EU FP7 MARS project has published its final project report (pdf). 

The final MARS report gives a breakdown of project activities and results over the last four years. Significantly, it shows that the project has resulted in over 230 scientific publications, numerous policy briefs and factsheets, and a suite of online tools for water management. (read more)

+++

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

5412835978_8df73b74b2_o

Clear waters and altered river bank at the Čunovo Dam on the Danube River in Slovakia. Image: Miroslav Petrasko | Flickr Creative Commons

Rivers across the world support rich biodiversity, yet are some of the most threatened global ecosystems, as a result of multiple pressures including pollution, water abstraction, habitat alteration and dam construction. As a result, river conservation and restoration are key topics for scientists, environmental managers and policy makers globally.

A new book Riverine Ecosystem Management: Science for Governing Towards a Sustainable Future provides a cutting-edge overview of contemporary approaches to river management. Available as a free PDF and ePub download, the book is edited by Stefan Schmutz and Jan Sendzimir from BOKU. (read more)

+++

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

river eea

The Neckar River at Ladenburg, Germany, which has significant hydromorphological alterations. Image: EEA

Less than half of Europe’s rivers, lakes and estuarine waters reach good ecological status, according to a recently published European Environment Agency report. Only 40% of European surface water bodies were found to be in a good ecological state, despite significant policy and management initiatives in recent decades to conserve and restore them. Roughly the same percentage (38%) of surface waters reach good chemical status, whilst nearly half (46%) do not.

The EEA report is based on data from EU-member states monitoring their surface and ground waters as part of the Water Framework Directive River Basin Management Plans (RBMPs). The report is the first overall assessment over European waters since 2012, and covers the second round of RBMP reporting. It contains data on over 130,000 water bodies across Europe, which have been monitored over the last six years. (read more)

+++

Postcards from Heatwave Europe (August)

IMG_1127

Low water levels on Lake Nisser in Norway. Image: Anne Lyche Solheim

Across the world, this summer’s weather has been characterised by extremes. The USA has experienced severe droughts and wildfires in the West, and flash flooding in the East, whilst an ‘unprecedented’ heatwave in Japan has been attributed as the cause of over 65 deaths. Most of Europe has experienced an extended period of high temperatures and minimal rainfall, causing wildfires to spread in both the Arctic Circle and Greece.

The high air and water temperatures, low rainfall and flashy storms and flooding experienced across Europe are all key pressures on the health and status of freshwater ecosystems. To gain a picture of how this summer’s weather is affecting European waters, we put a call out to our network of aquatic scientists across the continent, asking them to send in brief ‘postcards’ of their observations. (read more)

+++

More Postcards from Heatwave Europe (August)

DjInmK3X4AIDnzN

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

We recently published the first in a series of ‘Postcards from Heatwave Europe‘, in which aquatic scientists from across Europe offered their observations on how this summer’s extreme weather was affecting rivers and lakes in their local landscapes.

Today we have two more contributions to the series, from Sweden and the English Lake District. In Britain, at least, the weeks of hot, dry weather experienced this summer have recently been replaced by more unsettled conditions and regular thunderstorms. However, water levels in many lakes and rivers have yet to return to typical summer levels as a result of the prolonged dry spell. (read more)

+++

The Alliance for Freshwater Life is launched (August)

7_Vjosa upstream meander_(c) LukasTB

The Vjosa river and floodplain in Albania: one of the last intact large river systems in Europe. Image: Lukas Thuile Bistarelli

A new global network aiming to halt and reverse the ongoing freshwater biodiversity loss crisis launched last Sunday at the World Water Week conference in Stockholm. The Alliance for Freshwater Life is an interdisciplinary network of scientists, conservation professionals, educators, policy experts, creative practitioners, and citizens working to improve the conservation and sustainable use of freshwater ecosystems and biodiversity. (read more)

+++

Lake type affects how climate change causes algal blooms in European lakes (September)

2007_08_Loch Leven bloom3

Algal bloom on Loch Leven in Scotland. Image: Laurence Carvalho

Blooms of blue-green algae – otherwise known as cyanobacteria – are likely to increase in European lakes as a result of climate change, according to a new study. However, this trend is likely to vary depending on the individual characteristics of different lakes.

Writing in Global Change Biology, Dr. Jessica Richardson from the Centre for Ecology and Hydrology and colleagues used data from lakes across Europe to explore the sensitivities of different types of lakes to multiple environmental stressors associated with climate change and human activities. (read more)

+++

Microplastics found in fifty percent of insects in South Wales rivers (October)

300792407_8725b03518_o

The River Usk in South Wales. Half of the aquatic insects sampled in the river were found to contain microplastics. Image: Photo Monkey | Flickr Creative Commons

A new open-access study by researchers from Cardiff University found that half of aquatic insects (or macroinvertebrates) sampled from three rivers in South Wales had ingested microplastics.

A research team led by Fred Windsor, a PhD researcher at Cardiff University School of Biosciences, sampled three different kinds of mayfly and caddis larvae at five sites on the Usk, Taff and Wye catchments. Each sampling site was located close to a waste water treatment plant, allowing macroinvertebrates to be sampled for microplastic ingestion both above and below water outflows from each plant. (read more)

+++

Over a third of natural wetlands lost globally since 1970 (October)

boubyan_3

Mubarak Al-Kabeer Reserve – a Ramsar site in Kuwait where shallow salt marshes and small lagoons provide a key habitat for migratory birds. Image: Abdualreda Alramzi | Ramsar

Over a third of natural wetlands have been lost globally since 1970, a rate of decline which is three times that of global forest loss over the same period. Wetlands are important habitats for wildlife, and provide a number of important ecosystem services to humans, including food security, flood protection and climate change mitigation. However, wetlands are being lost due to human development across the world, putting a quarter of the plants and animals which depend on them at risk of extinction.

These are some of the key findings of the new Global Wetland Outlook report, published by the Ramsar Convention on Wetlands, an international treaty on wetland conservation. The report – the first global wetland inventory of its kind – has been published to coincide with the 13th Ramsar Convention of Parties, held this week in the United Arab Emirates. (read more)

+++

Global freshwater species populations decline by 83% since 1970 (November)

wwf freshwater lpi 2018

Image: WWF

Global freshwater species populations have dropped by 83% since 1970, according to a new report published by the World Wildlife Fund. The Living Planet Report 2018 assessed the populations of 880 representative freshwater species across the world between 1970-2014 to calculate the Living Planet Index.

The WWF report states that freshwaters – including lakes, rivers and wetlands – are the most threatened of all global habitats. Freshwater ecosystems provide habitat for over 100,000 known species of fishes, molluscs, reptiles, insects, plants and mammals, despite covering less than 1% of the Earth’s surface. (read more)

+++

Managing multiple stressors in aquatic ecosystems: recommendations from the MARS Project (November)

mars recs

The MARS project has published a document titled “MARS Recommendations on how to best assess and mitigate impacts of multiple stressors in aquatic ecosystems”. This open-access pdf outlines a framework for how multiple stress conditions might be best mitigated in River Basin Management through the EU Water Framework Directive. (read more)

+++

Emerging threats and persistent conservation challenges for freshwater biodiversity (December)

2169003862_7fdd908340_o

A stream illuminated by street lights. Light pollution is one of the emerging threats to freshwater ecosystems identified by the review. Image: Eric Fleming | Flickr Creative Commons

A new review of emerging threats to freshwater biodiversity, and the conservation challenges they pose, has been published. The review, led by Andrea Reid from the Fish Ecology and Conservation Physiology Laboratory at Carleton University, Canada, argues that the Anthropocene has brought numerous new and varied threats that disproportionately impact freshwater systems.

Writing in Biological Reviews, the authors state that new and effective conservation strategies are needed to address emerging threats, particularly because whilst freshwaters cover only 2.3% of the Earth’s surface, they support at least 9.5% of the Earth’s described animal species. (read more)

+++

Thanks for reading, and a very happy 2019 to you! If you still have an appetite for more freshwater blogs, then you can also read our previous annual post round-ups for 2017 and 2016.

Emerging threats and persistent conservation challenges for freshwater biodiversity

December 21, 2018
abstract river

Numerous new threats to freshwater ecosystems have emerged in the last decade – many of which are poorly understood and difficult to manage. Image: Mark Strozier | Flickr Creative Commons

In 2006, freshwater scientist David Dudgeon and colleagues published a comprehensive review of the threats facing freshwater ecosystems and the urgent conservation actions required to tackle them. In the twelve years since their widely-cited review, the outlook for freshwater biodiversity has worsened, with freshwater species exhibiting steeper population declines (see our blog here) than marine and terrestrial species.

Dudgeon and colleagues identified five key threats to freshwater ecosystems: overexploitation; water pollution; flow modification; destruction and degradation of habitat; and invasion by exotic species. In the years since their paper, many of these threats have become more widespread and complex, whilst new and emerging threats have been identified, and the harmful effects of multiple stressors have been increasingly documented.

In other words, freshwater conservation now takes place in what is increasingly called the Anthropocene – a geological epoch characterised by human activity affecting environments and ecosystems at all scales.

light river

A stream illuminated by street lights. Light pollution is one of the emerging threats to freshwater ecosystems identified by the review. Image: Eric Flemin

In this context, a new review of emerging threats to freshwater biodiversity, and the conservation challenges they pose, has been published. The review, led by Andrea Reid from the Fish Ecology and Conservation Physiology Laboratory at Carleton University, Canada, argues that the Anthropocene has brought numerous new and varied threats that disproportionately impact freshwater systems. Writing in Biological Reviews, the authors state that new and effective conservation strategies are needed to address emerging threats, particularly because whilst freshwaters cover only 2.3% of the Earth’s surface, they support at least 9.5% of the Earth’s described animal species.

Reid says, “Since 1970, freshwater species have declined by a staggering 81% compared with <40% species declines both on land and in our oceans – why is freshwater biodiversity declining so severely and what are the biggest threats putting freshwater species in jeopardy? Freshwater ecosystems, like our lakes, rivers and wetlands, surround us and we rely on them for clean drinking water, hydropower, nutrition, recreation, navigation, scenic values, and much more. As these ecosystems become increasingly endangered, their ability to provide these services that underpin human wellbeing gets diminished.

Sadly, the current scale of freshwater declines is now so grave that we consider it an invisible tragedy – hidden beneath the water surface – that attracts far too little public, political, and even scientific interest. We are hoping to change this narrative through the publication of our article.”

emerging threats reid et al 2018

The twelve key emerging threats to freshwater ecosystems and their characteristics. Adapted from Reid et al 2018.

The authors identify twelve threats to global freshwater biodiversity which have either emerged or intensified since Dudgeon and colleagues’ 2006 review. Summarised in the graphic above, the paper shows the startling range of pressures on global freshwater ecosystems, which can potentially act in tandem in unpredictable ways as multiple stressor ‘cocktails’.

Co-author Prof Steve Ormerod, from Cardiff University School of Biosciences explains, “In this new review we wanted to update the story told by Dudgeon and colleagues – particularly with respect to problems affecting freshwater ecosystems that have emerged more prominently: climate change, invasions, diseases, harmful algal blooms, expanding hydropower, emerging contaminants, engineered nanomaterials, microplastics, light and noise, salinisation, declining calcium concentrations and cumulative stressors.

For each, we offer a specific overview, but come to the general view that an already dire prognosis for freshwater biodiversity is worsening while still being overlooked by many – perhaps even most – conservation biologists and ecologists. Mindful of the need to inspire action, however, we offer evidence where restorative and protective actions have benefited freshwater ecosystems: without hope, we cannot bring about the global efforts required to protect fresh waters as ecosystems that are fundamental our own ability to survive.”

microplastics

Microplastic pollution is one of the twelve emerging threats identified in the study. Image: Florida Sea Grant | Flickr Creative Commons

The authors highlight five approaches to freshwater management and conservation which have the potential to address some of the emerging threats. First, environmental DNA (or eDNA) can be detected in water samples to detect the presence of rare and endangered species, or to track the spread of invasive species. Second, maintaining natural water allocations and variability (or environmental flows) in rivers and streams threatened by abstraction or flow alterations is an increasingly popular management approach to support resilient freshwater ecosystems.

Third, the negative impacts of aquaculture – parasites and invasive species, for example – can be minimised by supporting healthy freshwater ecosystems with fish stocks which can be sustainably harvested, the authors argue. Fourth, removing river obstacles such as dams and fishways can have significant ecological benefits to migratory species, although dam construction rates remain high in many areas. Fifth, the authors highlight the potential of managed relocation of species which will lose their climatic niche under future climate change; however, they note that this is a strategy with high levels of uncertainty over both appropriateness and effectiveness.

The authors highlight a number of freshwater conservation policy mechanisms and societal groups which might help mitigate emerging threats. These include regulatory instruments (e.g. The Water Framework Directive); fiscal incentives (e.g. agri-environment schemes); market opportunities (e.g. investments in ecosystem services with financial returns); and societal actions (e.g. campaigning for dam removal, participation in conservation activities, framing freshwaters as a political voting issue). Accordingly, the authors advocate for an increased global focus on freshwater threats and conservation, citing the recently formed Alliance for Freshwater Life, the 10 steps for responsible inland fisheries in the Rome Declaration and the post-2020 planning beyond the Aichi Biodiversity Targets as important steps in this direction.

However, the new review clearly highlights the significant multiple pressures – some known, some emerging – that are causing ongoing biodiversity losses in freshwater ecosystems across the world. Awareness of these threats and trends must spark positive conservation action. As the authors conclude, “We are merely at the beginning of the ‘great acceleration’ of the Anthropocene. Indeed, we may not even be able to imagine which environmental challenges we will face in the coming decades. In order to protect biodiversity and to support human well-being, we need to manage fresh waters collectively across sectors and as hybrid systems – managing freshwater ecosystems as both a pivotal resource for humans as well as highly valuable ecosystems.”

Reid, A. J., Carlson, A. K., Creed, I. F., Eliason, E. J., Gell, P. A., Johnson, P. T., Kidd, K. A., MacCormack, T. J., Olden, J. D., Ormerod, S. J., Smol, J. P., Taylor, W. W., Tockner, K. , Vermaire, J. C., Dudgeon, D. and Cooke, S. J. (2018), Emerging threats and persistent conservation challenges for freshwater biodiversity. Biol Rev. doi:10.1111/brv.12480

%d bloggers like this: