Free the Snake: Restoring America’s Greatest Salmon River
Free the Snake is a short film about the restoration of the Snake River in Washington State, USA. Featuring interviews with Professor David Montgomery from the University of Washington, Bruce Babbitt, former Secretary of the Interior and novelist David James Duncan, the film focuses on the ecological and hydrological impacts of four major dams along the river.
In particular, the dams fragment migration routes of Pacific salmon upstream to spawning grounds, with damaging consequences for the health and size of their populations. But, all hope is not lost. When discussing the possibility of dam removal, David Montgomery suggests that, “The beautiful thing about salmon, if you look at their history, is that they’re resilient. If you give them half a chance then they can come back.”
The Emån River in Southern Sweden, one of the sampled rivers. Image: Wikipedia
We live in an age of widespread ecological restoration, in which centuries of human impacts on the environment are being addressed, under guiding principles such as rewilding, biodiversity conservation and ecosystem service provision. Restoration projects are particularly common on rivers and streams, partly because these ecosystems have often been particularly impacted by pollution, fragmentation and so on; but also because restoration approaches such as weir removal, ‘daylighting’ and riparian zone planting have become widely adopted. However, despite the increasing number of river restoration projects implemented across the world, there is still sparse scientific evidence on the long-term effects of such projects, and the factors affecting their success or failure.
A new study by MARS project leader Daniel Hering and colleagues addresses this shortfall in knowledge by studying the effects of the restoration of river hydromorphology on aquatic habitats and biodiversity. Hydromorphology is the term used to bring together the interactions of hydrology (e.g. water flows), geomorphology (e.g. bedrock) and ecology (e.g. plant and animal communities) in river or stream. Hydromorphological processes include the formation of meanders, riffles and pools: all of which contribute to a diverse set of habitat niches for freshwater life.
As reports such as the 2012 European Environment Agency ‘European Waters: assessment of status and pressures‘ outline, there is increasing evidence that river hydromorphology often has a strong impact on the health and diversity of aquatic ecosystems. However, projects which restore river hydromorphology often have limited effects on freshwater biodiversity. One common explanation for this effect is that river restoration often takes place over short sections of river, which are insufficient to allow ecological communities to develop, and geomorphological processes to take place.
The River Skjern, the largest river in Denmark, and another sampling site. Image: Wikipedia
To investigate this phenomenon, Hering and colleagues undertook experiments on rivers in ten regions across Northern Europe, as part of the EU REFORM project. For each region, they studied the impacts of two restoration projects: one on a short section of river; one on a longer section. At each section of restored river, the team sampled habitat composition in the river and its floodplain, three aquatic organism groups (aquatic plants, insects and fish), two floodplain-inhabiting organism groups (floodplain vegetation, ground beetles), and food web composition and land–water interactions. These findings were then compared to samples taken upstream at non-restored sections of river of roughly equal length.
After accounting for regional variations in river size and restoration approaches, the team, publishing in the Journal of Applied Ecology, found that the length of the restored river made no significant difference to its ecological health and diversity, as sampled by the range of indicators above. Instead, they found that what mattered was the substrate composition of the river bed: in other words, the aquatic habitat it provides for organisms.
Where habitat had been created in restoration, populations of fish, aquatic insects, aquatic plants and floodplain vegetation increased, regardless of the length of the restored river section. Substrate habitat restoration might include measures such as increasing the number of boulders or presence of wood (for example tree trunks) to diversify water flows and depths, and habitat niches for different aquatic organisms.
Whilst in-stream habitat restoration was important for aquatic biodiversity, restoration projects also had pronounced impacts on floodplain ecology. The authors suggest that this is because hydromorphological restoration, even at relatively small scales, tends to create habitat types close to the river bank (such as gravel and sand bars), which are often completely lacking in degraded sites. Such habitat types are rapidly colonized by ground beetles and, to a lesser degree, by specialised floodplain vegetation. Both organism groups have comparatively high dispersal abilities and are less affected by barriers such as weirs when compared to aquatic organism groups.
Overall, the study suggests that the ecological success of river restoration for aquatic organisms doesn’t depend on the length of restored river, but rather the quality and diversity of habitats on the river’s bed. However, for floodplain organisms, relatively small-scale restoration projects may yield significant positive effects.
Ecological surprises: why multiple stressors in freshwaters may cancel each other out
Algal blooms in the Lake of Menteith, Scotland. Image: Dr Richard Murray | Creative Commons
Stressors are environmental changes that place stress on the health and functioning of an ecosystem. There is increasing evidence – largely from marine environments – that multiple stressors may interact to produce unexpected effects on aquatic ecosystems. However, there is a pressing need to better understand the ‘ecological surprises’ caused by multiple stressors in freshwater ecosystems (a point made in papers by MARS scientists Steve Ormerod in 2010 and Daniel Hering and colleagues in 2015).
Existing scientific literature from marine environments show that multiple stressors can have effects that are greater than the sum of those caused by individual stressors. This ‘synergistic’ interaction poses important questions for environmental managers and policy makers. In short, it is difficult enough to manage individual stressors such as pollution, habitat destruction and overfishing, without the unexpected and, as yet, largely unpredictable interactions and effects these stressors might have.
In the light of this uncertainty, a team of researchers from the University of Pretoria in South Africa and the University of Alberta in Canada analysed data from 88 existing scientific studies that show the responses of freshwater ecosystems to pairs of stressors. The team, led by Michelle Jackson from the University of Pretoria, brought together the findings of these studies to investigate the characteristics and effects of different stressor interactions; and the extent to which interactions vary between different stressor pairs and response measurements.
Freshwater stressors may cancel each other out
Recently published in Global Change Biology, the team’s findings are perhaps surprising, at least initially: the environmental effects caused by pairs of stressors in freshwater was most often less than the sum of their single effects. This is known as an antagonistic interaction, where two or more stressors interact to cancel out some or all of their individual effects.
Across the 88 surveyed studies, stressors included acidification, increased water temperatures, ultraviolet radiation, contamination, nutrification, habitat alteration and invasive species. Antagonistic interactions were found in the majority (41%) of surveyed studies, affecting animal abundance, biomass, condition, growth/size and survival and plant diversity. The authors suggest that this widespread antagonism could be due to the effects of the stronger stressor overriding and negating those of the weaker one. Here, environmental managers might seek to rank the effects of the strongest stressor in an antagonistic interaction in order to forecast the cumulative impacts of multiple stress.
Another suggestion is that exposure to one stressor can result in greater tolerance to another. An important point made here is that there may exist a potential for co-adaption within freshwater ecosystems to minimise the net effects of multiple stressors. However, despite the predominantly antagonistic interactions, net effects of multiple stressors were still mostly negative, underlining the widespread threats faced by freshwater ecosystems.
Multiple stressors in freshwaters: the overall picture
Overall, the net effects of stressor pairs were frequently more antagonistic (41%) than synergistic (where the overall effect is more than the sum of individual stressors: 28%), additive (overall effect is equal than the sum of individual stressors: 16%) or reversed (overall effect is opposite to the positive / negative effect of individual stressors: 15%).
Synergistic interactions between multiple stressors such as increasing sea temperatures, species invasions and habitat destruction have been observed in a number of studies of marine ecosystems. Why is the picture different for freshwaters? The authors suggest that this is due to greater inherent environmental variability in smaller aquatic ecosystems, which fosters higher potential for ecological acclimation and co-adaptation to multiple stressors.
Antagonistic interactions were most frequently observed in affecting animal condition; synergies and reversals with plant growth and size; and additive effects with plant diversity. This variability shows that it is important to consider the ecological metrics used to measure the impacts of multiple stressors.
The Inco Superstack in Sudbury, Ontario in Canada. Part of a large copper smelting works, the chimney emitted sulphur gases which caused acidification in surrounding lakes through the mid 20th century, requiring significant ecological restoration work in the 1990s. Image: P199 | Wikipedia | Creative Commons
Different effects on ecosystem diversity and function
Interestingly, multiple stressors had different effects on the diversity and function of ecosystems. Multiple stressor interactions affecting species diversity were most often additive. This suggests that the species eliminated by one stressor were often not the same as those eliminated by the second, and additional stress causes additional species loss.
On the other hand, the most common interaction affecting the functional performance of an ecosystem was antagonism. This may be a result of a process known as compensatory species dynamics. Here, the remaining species in the stressed ecosystem may compensate functionally (e.g. in nutrient cycling) for species loss. This in turn points to the idea that an ecosystem’s functional resilience to stress is not simply dependent on biodiversity, but instead determined by species identity and traits. In short, the findings here suggest that freshwater biodiversity is more sensitive than ecosystem function to the impacts of multiple stressors.
‘Ecological surprises’
The authors identified that 15% of studies showed reversal effects from multiple stressors. These reversals are termed ‘ecological surprises’, in that they reverse the environmental impacts – negative to positive (or vice versa) – caused by the individual stressors. Whilst reversals were the least common type of interaction observed, their existence has potentially important effects for environmental management.
The stressor most commonly associated with reversal interactions was climate warming. For example, a study by Patrick Thompson and colleagues in 2008 found that warming reversed the negative effects of excess nitrogen supply on phytoplankton growth, possibly as a result of increased conversion of nitrates and ammonia by enzymes as a result of increased temperatures. Ecological responses to temperature change are complex, but the evidence here on multiple stressors causing reversals suggests that there may be ever more ‘ecological surprises’ in a warming world.
Lessons for freshwater conservation management
The paper contains potentially important lessons for freshwater conservation management. For multiple stressors that generate additive or synergistic interactions, management that focuses on a single stressor should cause a positive outcome. However, in ecosystems affected by antagonistic stressor interactions, both stressors may need to be removed in order to foster any significant ecological recovery.
Introducing the MARS Project: a short documentary
The MARS project has now been running for well over a year, and many of the project experiments are beginning to yield results. Today we’re happy to share a short new documentary about the project, which you can watch above.
The film explains the problems posed by multiple stresses such as nutrient pollution and climate change on freshwater ecosystems, and the ways in which the MARS project is implementing innovative scientific research to better understand and manage their effects.
The new documentary features interviews with MARS scientists Anne Lyche Solheim from NIVA in Norway and Steve Ormerod from Cardiff University in Wales, and Anders Iversen, Water Framework Directive Co-ordinator at the Norwegian Environment Protection Agency. It shows fascinating new footage of MARS stream experiments in the Austrian Alps, and deep lake experiments at the IGB LakeLab research station on Lake Stechlin in Northern Germany.
The piece was predominantly filmed on two heavily stressed and modified rivers: the Emscher in Germany and the Calder in West Yorkshire, England. Additional footage was shot on the upland River Hodder in Lancashire, England. The footage of the underwater char was shot by Jack Perks (who we’ve featured on the blog before), and the footage of the blue-green algal bloom was filmed by Scott Nelson (whose Rivière des chutes film will be featured here soon).
We hope you enjoy the film.
What influences the ecological success of river restoration?
A section of the renaturalised River Emscher in Germany. Image: DESSIN Project
In the last twenty years or so, environmental managers on many rivers and streams around the world have undertaken restoration schemes in an attempt to rectify the ecological damage caused by decades – if not centuries – of human modifications and pollution.
Just last week, the Environment Agency in the UK announced that populations of lampreys – eel-like ‘living fossils’ which were around 200 million years before the dinosaurs – have started to return to rivers in Northern England – heavily polluted and fragmented in the Industrial Revolution – for the first time in decades. Populations of migratory river and sea lampreys are beginning to return to the Derwent, Ouse and Trent as a result of EA restoration work which has improved water quality and removed barriers to migration through innovative ‘lamprey tiles’ that allow the fish to use their suckers to navigate over obstructions such as weirs.
River restoration schemes take a range of different approaches. Many restoration projects attempt to recreate ‘natural’ river processes and features such as flow amount and speed, stream depth and width, meanders and riffles. Another common restoration approach is to remove human barriers such as weirs and dams to improve continuity and connectivity between different habitats along a river’s course.
Other restoration approaches focus on the areas of land around rivers, planting strips of riparian vegetation along the river, to buffer pollutants and sediment from reaching the river, or using environmental policy to reduce groundwater abstraction from agriculture and industry. And finally, some restoration schemes focus on reintroducing plants and animals that have been lost over time – for example beavers or juvenile salmon. Most river restoration schemes use a combination of these approaches, depending on the individual river to be restored, its ecological and social histories, and the various priorities for restoration outcomes.
But as yet, there is little synthesised information on the factors that influence the success of river restoration initiatives across the world. However, a new study bringing together all the available global scientific literature and data on the ecological effects of river restoration, led by Jochem Kail from the University of Duisberg-Essen in Germany and published in Ecological Indicators, may help shed new light on this shortfall, and help guide environmental managers in designing restoration work.
Kail and colleagues from Masaryk University in the Czech Republic and BOKU in Austria, compiled river restoration monitoring results and scientific literature and databases to quantify the effects of restoration measures on three organism groups: fish, aquatic insects (macroinvertebrates) and aquatic plants (macrophytes). The team then looked to identify the factors that most strongly influence the effects of river restoration.
Kail explains the rationale for this research, “There is currently a controversial discussion about whether river restoration “works” – i.e. has a significant effect on biota – and scientific studies show contrasting results of restoration. Existing river restoration studies have already been summarised in several narrative reviews but quantitative summaries – so called “meta-analyses” – are rare and missing at a global scale. Our meta-analysis of studies from around the world on different organism groups might fill this gap: providing another – hopefully helpful – piece of the puzzle to inform environmental managers and policy makers.”
The Elwha River in Washington State, USA. The largest dam removal project in history took place on the river between 2011-14 as part of restoration work by the National Park Service. Image: Wikipedia
Funded by the EU REFORM project, the team’s results show that river restoration has significant, but varied, effects on all three organism groups. In general, restoration projects had a positive ecological effect, but around one-third showed negligible or negative effects. The responses of aquatic plant richness and diversity to restoration were higher than those for fish and insects. Aquatic plant richness and diversity was most significantly increased by river widening and rebraiding projects. This is because such initiatives reduce flow velocities and often cerate sparsely shaded pioneer habitats such as bare riparian areas and gravel bars that encourage the spread of pioneer plants, both in and around the river.
Fish and aquatic insect populations benefited from instream restoration measures, such as river margin enhancement, riffle creation and boulder placement. For all organism groups, abundance and biomass was more frequently increased than richness and diversity. Kail and colleagues suggest that this is because it is generally easier to increase population numbers of existing organisms in a restored river ecosystem than it is to establish new species.
River restoration effects were most strongly affected by agricultural land use around the river, river width and restoration project age. Agriculture around the restored river generally inhibited the positive ecological effects of restoration. However, drawing out large-scale trends from from complex and locally-specific land use patterns is difficult.
Project age was the most important factor influencing the effects of river restoration, but the effects of age were found be unpredictable and even negative on the health of the ‘restored’ ecosystem. This means that the positive effects of restoration may vanish over time, requiring long-term monitoring and adaptive management of restoration initiatives.
As an example, Kail and colleagues found that the response of aquatic plant abundance to restoration was reduced in older projects, suggesting that this can be due to the initial restoration processes of river widening and meandering not persisting in the restored ecosystem, and as such, the niches for many plants being lost over time. However, the results from the surveyed scientific literature were variable and showed no clear trend, both across organisms and ecosystems.
This finding raises the question of how, and perhaps more specifically when, to assess the success of river restoration initiatives. Typically, restoration projects require many years to mature and to impact the diverse and complex components of an ecosystem. However, Kail and colleagues’ study suggests that some river restoration projects may have positive ecological effects within a few years, that then diminish over time.
Kail explains, “The time since project implementation was the most important factor in influencing the effects of restoration, but these effects did not simply increase over time as one might expect. Instead, they showed different and non-linear relationships and effects even vanished over time in some studies. So we might ask: what about the long-term effects of restoration? Does it really help to establish more natural communities besides simply increasing the pure number of species, which might include mainly common or even non-native species? These are just some of the debates and frontiers in river restoration ecology.”
This innovative meta-analysis suggests that whilst river managers can generally expect positive effects from river restoration work on the three organism groups – fish, aquatic insects and aquatic plants – surveyed here, such initiatives may not be successful if initial work is not followed up with long-term ecological monitoring of the restored river, and adaptive management to intervene where restoration measures have altered or diminished effects.
Wildlife photographer Neil Phillips captures the curious and beautiful diversity of underwater life
An unfamiliar view of a familiar creature: the common backswimmer (or water boatman). Image: Neil Phillips
For a while now, we’ve been enjoying fantastic wildlife photographs taken by Neil Phillips and posted on his @UK_Wildlife twitter page. Many of Neil’s photographs capture otherwise unseen views of underwater life, providing a window into this diverse and often beautiful submerged world.
We contacted Neil to find out more about his process and rationale for taking photographs of freshwater life. His response is posted below, alongside a number of his stunning photographs.
A female pirate spider with egg case. Image: Neil Phillips
I did try a few time to photograph the fish and other creatures in my tropical freshwater aquarium at home, which were mostly failures due to reflection from the onboard flash, though I did manage a couple of photos of my pet caecilians (a type of legless amphibian)
A caecilian, a legless amphibian. Image: Neil Phillips
It was not until I started my job in environmental education I really tried again, this time using flash off camera and putting a dragonfly nymph in an old small display aquarium. The shots I got were OK but I still had a way to go.
Emperor dragonfly nymph. Image: Neil Phillips
Four spotted chaser nymph. Image: Neil Phillips
Soon after this I came across another book with a triangular design for a photographic aquarium and set about building my own (with some help from my dad) from small bits of glass I bought from a local glazier. With this new aquarium, I started getting images that I was happy with.
Water louse. Image: Neil Phillips
The setup I use now is a small triangular or rectangular tank with something natural coloured for the background, filled with filtered clean water, and using my Pentax K-3 and the DFA 100mm macro lens, with the flash (with a diffuser) on the off camera flash cable.
Tank set up for photographing underwater life. Image: Neil Phillips
Screech beetle. Image: Neil Phillips
Phantom midge larvae. Image: Neil Phillips
You can also visit Neil’s website, his Flickr photo gallery, and follow him on twitter @UK_Wildlife
Mosquito larva. Image: Neil Phillips
Darter dragonfly nymph. Image: Neil Phillips
The IUCN Freshwater Plant Specialist Group
River Water-dropwort. A species that is Near Threatened outside of populations in rivers and streams in the UK and Ireland. Image: R Lansdown
The IUCN Freshwater Plant Specialist Group is a global network of scientists and researchers with an interest in the conservation of wetland plants. It was formed initially with the support of the Fondation Tour du Valat and Plantlife under the umbrella of the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN).
The Freshwater Plant Specialist Group is one of around 120 Specialist Groups coordinated by the IUCN Species Survival Commission. These are communication networks of people with a common interest, which exist to support and further the conservation of the organisms for which they are responsible. Each Group has a Chair (responsible for the overall coordination of the Group), a Red List Authority (responsible for the coordination of IUCN Red List assessments of extinction risk) and members.
Lesser water-plantain, a flowering herb found in peaty bogs and ponds. Image: R Lansdown
The Chair of the Group, Richard Lansdown (whose fantastic photographs illustrate this piece) explains more:
“The Freshwater Plant Specialist Group was initiated after discussion between Will Darwall of the IUCN Freshwater Biodiversity Unit and me around a meeting of the IUCN Freshwater Conservation Steering Committee on which we both serve in June 2011. IUCN had long been looking to establish a freshwater plant specialist group but was looking for the right chair.
My proposal to establish the group, supported by the Fondation Tour du Valat and PlantLife was unanimously agreed at a meeting of the IUCN Council in June 2011. I was initially reluctant to commit to establishing the group but was convinced by the people I met at the second meeting of the IUCN SSC Specialist Group Chairs in 2012. I formally signed the papers establishing the group in 2013. The Freshwater Plant Specialist Group now has over 140 members in more the 60 countries, with many organisation represented among the members.”
Eryngium corniculatum, a plant of Mediterranean wetlands. Image: R Lansdown
The Freshwater Plant Specialist Group exists to promote and further the conservation of wetland plant species and the habitats upon which they depend. Its aim is to achieve this through a combination of:
- Establishing a database of all aquatic and wetland plants, including vascular plants, bryophytes, lichens and algae that are dependent upon wetlands. The database will store information on the taxonomy, nomenclature and distribution of each species, with the aim that it be improved through review by FPSG members. The foundation of the database has been established with funding from EU Biofresh (Biodiversity of Freshwater Ecosystems) project and work by Nur Ritter.
- Assessment of the conservation status of all wetland-dependent plants using the IUCN Red List categories and criteria.
- Preparation of action plans for the conservation of wetland-dependent plants, initially concentrating on specific regions for which a regional Red List assessment of freshwater-dependent plants has been completed.
- Support for individual projects proposed by the members. This support will mainly take the form of providing information and links to contacts, as well as assistance with preparation of funding proposals.
Ranunculus hybrid in the River Creuse, France. Image: R Lansdown
Richard further outlines the collaborative nature of the Group:
“Although specifically aimed at conservation of wetland-dependent plants, wetland conservation cannot be successful without information on the environment on which the plants depend, or on methods of managing this environment. Therefore, whilst the membership of the group will be dominated by botanists, people with an interest in plants but their main knowledge and experience in other disciplines such as hydrology, geology, geomorphology and water management will also be welcomed as members.”
Read more about the Freshwater Plant Specialist Group here.
Hippuris x lanceolata, a hybrid species of mare’s tail, found in many waterways across Europe. Image: R Lansdown
One of the most important areas of work in the MARS project is modelling how freshwater ecosystems (and the services they provide) respond to multiple stressors at a river basin catchment scale.
A group of MARS scientists working on river basin modelling recently met for five days in Tulcea, Romania, to collaboratively develop and standardise their use of statistical analysis.
MARS scientist Christian Feld was on hand to take a selection of photographs at the workshop: both of the participants at work, and of the beautiful River Danube and surrounding landscape.
Tweeting the Freshwater Glossary
It is largely agreed that the results of scientific research should be made available to public audiences in ways that are as clear and accessible as possible. This is a big challenge for scientists and science communicators. There are many convincing arguments that making scientific research available to the public – and particularly in engaging in dialogue about it – is a valuable step in fostering democratic and transparent political decision-making about big issues.
However, scientific research is often structured and carried out using key terms and phrases that aren’t regularly used in most of our daily lives. This can sometimes make it difficult to understand (and even communicate) why and how scientific research is undertaken and the outcomes it might have for public and political life.
This is why the Freshwater Glossary has been established on the Freshwater Information Platform website. The Freshwater Glossary collects a large set of key terms and phrases that underpin freshwater science, and gives short descriptions of what they mean.
Collected from a number of previous European Union projects, the Glossary is designed to help anyone – whether an interested layperson, student, researcher or policy maker – get to grips with some of the most important terms and concepts in freshwater science.
Over the coming weeks, we’ll be sharing the Freshwater Glossary through our Twitter account @freshwaterblog. We encourage you to follow us on Twitter (if you’re not signed up, there’s a large and vibrant community of water professionals, managers, researchers and policy makers on the site, making it potentially very rewarding) and to share the Glossary tweets if you’re so inclined.
Similarly, if there are any key terms or phrases that you feel are missing from the Glossary, then please leave a comment here or email info@freshwaterplatform.eu
The MARS ‘cookbook’ for assessing freshwater multiple stresses and ecosystem services
River Great Ouse in arable farmland in Southern England. Multiple stressors from nutrient pollution affect the ecosystem services that this river can provide. Image: Hugh Venables | Creative Commons
Last week we wrote about the new MARS factsheets, which are designed to give brief, accessible and engaging introductions to some of the key freshwater topics covered by the project. This week, we introduce the first factsheet (pdf), which outlines the new ‘cookbook’ methodology for understanding how multiple stressors on freshwaters affect the ecosystem services they can provide to humans.
The MARS project assesses the impacts of multiple stressors on the provision of ecosystem services from freshwater ecosystems, under different climatic and land-use scenarios. The project has developed an innovative new assessment methodology – termed a ‘cookbook’ – to allow scientists, environmental managers and policy makers to quantify the relationships between multiple stresses and ecosystem service provision and value. The cookbook provides an invaluable tool to support the implementation of the Water Framework Directive in Europe.
The cascade model: quantifying the capacity, flow and benefits of ecosystem services
Building on the expertise of project partners and insights from wider scientific and economic research, the MARS cookbook uses a cascade model methodology (Figure 1) that links the structure and function of an ecosystem to its service provision. This methodology includes the capacity of an ecosystem to provide a service (assessed using biophysical data), the actual flow of the services used by humans (assessed using socio-economic data), and finally the benefits that ecosystem services provide.
By assessing both the capacity of an ecosystem to provide services, and the actual use of these services, the MARS cookbook methodology allows assessments on the sustainability of ecosystem use to be made. The unsustainable use of ecosystem services may become an additional stressor the ecosystem’s health and status.
The MARS cookbook: four steps
The MARS cookbook methodology is split into four steps. The first is scoping, the process by which the aquatic ecosystem and ecosystem services of interest are selected and mapped, and the spatial and temporal scale of analysis are defined. The second step is to develop the assessment framework, through which multiple stressors and ecosystem services are linked in a stressor-ecological status-ecosystem service series. A key step here is to check whether the ecological indicators used (e.g. biodiversity, ecological status) capture the effects of the stressors, and can be linked to the ecosystem services of interest.
The third step is assessment, where biophysical indicators are organised according to the ecosystem’s capacity to deliver a service, its actual use, and the resulting human benefits provided. Indicators are organised in three categories: capacity (e.g. biomass of commercial fish species); flow (e.g. fish catch); and sustainability (e.g. % of catch within sustainable limits). Their ability to indicate ecosystem stress and / or service provision is quantified through the computer modelling of existing ecological data.
The fourth step is valuation, to identify the benefits provided by ecosystem services and aggregate them at three scales: water body, catchment and European continent. The valuations are undertaken at appropriate scales to support decision making in Integrated River Basin Management Plans and the Water Framework Directive. In the valuation process, the ecosystem service, benefit and value are separated, because a service (e.g. water purification) can provide numerous societal benefits depending on the location (e.g. drinking water; swimming areas). The economic value of the ecosystem services provided can then be valued through revealed and stated preference methodologies, and cost-based and benefit transfer approaches.
Case study: applying the MARS cookbook to Welsh river catchments
To give an example of the methodology in action, we can apply it to water purification ecosystem services provided by rivers in Wales studied by MARS led by Steve Ormerod and Isabelle Durance at Cardiff University. The first analysis step defines the geographical area, the ecosystem service and the scale of analysis (amount of purification in the catchment per year). The second framework step links the pressures faced by the catchment (e.g nutrient pollution) to the ecosystem status and service provision.
The third biophysical assessment step analyses the ecological structure and processes (e.g. an analysis of the nutrient cycle) and selects ecosystem service indicators (e.g. nutrient retention levels). In step four, the economic benefits of the service are identified (e.g. free, clean water), and appropriately valued (e.g. unit cost of purification by alternative process). This value is then aggregated to the scale of interest (e.g. the catchment) to give an overall economic value of the water purification service provided by the ecosystem.
You can read and download all the MARS factsheets on the project website here.
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