PONDERFUL partner Jeremy Biggs, of Freshwater Habitats Trust in the UK, gave a presentation on the importance of ponds in a session entitled Unlocking the Potential of Wetlands for Addressing Climate Change and Biodiversity Loss.

Professor Biggs gave international delegates an overview of the PONDERFUL project and shared some early results, particularly on the role of pods and nature-based solutions for protecting freshwater biodiversity. He also highlighted the systematic bias against small waterbodies in policy, despite the fact that 90 percent of global standing waters are ponds of less than one hectare and most running waters are small or seasonal streams.

Established in 1971, the Ramsar Convention on Wetlands is an international treaty for the conservation and sustainable use of  wetlands. There are now more than 2,400 Wetlands of International Importance (Ramsar Sites) in 172 countries.

Professor Biggs’ presentation coincided with a draft resolution on enhancing the conservation and management of small wetlands, on which contracting parties are now due to vote. If passed, this new resolution will mean that small waterbodies are better represented within the Ramsar Convention, paving the way for future protection.

The draft resolution includes a number of measures, such as:

• Urging countries to designate small wetlands that meet the criteria as Wetlands of International Importance.
• Encouraging countries to develop national plans to promote the conservation and restoration of small wetlands and to effectively manage them to maintain threatened species.
• New guidance on conducting inventories and monitoring of small wetlands and their ‘multiple values for biodiversity conservation.’

Jeremy Biggs said: “Presenting at the Ramsar COP14 was an important oppportunity for PONDERFUL to reach an international audience. Along with other members of the consortium, I warmly welcome the proposed resolution, which is a very important signal of the value of ponds and other small water bodies for freshwater biodiversity.

“When we talk about freshwater and wetland habitats we naturally think of big rivers and lakes, and huge expanses of wetland. But in fact, the majority of wetlands are small. Most running waters are small headwater streams and 90% of standing waters are ponds. Evidence – which has been building over the last 20 years – now shows that these habitats are absolutely critical for supporting freshwater biodiversity. Unfortunately, this knowledge of the importance of small waters, has come rather late so they are not properly reflected in most policy.”

This talk was part of the side event to COP14, taking place from 5 to 13 November 2022 in Wuhan (China) and Geneva (Switzerland). The event, which focused on the role of wetlands in mitigating and adapting to climate change, protecting biodiversity and delivering ecosystem services was co-organised by the International Union for Conservation of Nature and the Geneva Environkment Network, with the support of Network Nature and the EU Commission.

Here we review some recent research and policy events of interest for freshwater ecologists that caught our eye and got us thinking – or suggested some practical actions we could take.

Ponds and other small waters

A PNAS paper on amphibian recovery following ‘massive pond creation’ in Switzerland was the most striking recent research result linked to PONDERFUL arguments. Over 20 years, the creation of hundreds of ponds in the Swiss canton of Aargau led to increases in 10 out of 12 resident amphibian species – including threatened species. The report is a powerful argument for the role of ponds and their benefits for amphibian biodiversity. It’s worth reading the details of the papers and extracting some of the nuances: the authors themselves noted that the pond type created was important, particularly citing Epidalea calamita (the Natterjack Toad) as one of the two species that did not increase. They commented that this was probably because they didn’t have enough of the ponds this species needs – which is shallow, seasonal and, in the Swiss context, grassy pools. The warm, short vegetation and open conditions with unpolluted temporary ponds needed by E. calamita, can be difficult to maintain.

It’s always useful to have more evidence of the value of ponds for biodiversity from different parts of the world. A recent paper from Bhutan has compared the richness of wetland plants in different waterbody types (echoing the original paper by PONDERFUL team member Penny Williams). The authors found that, although differences between waterbody types were not enormous, ponds were the richest habitats at regional level. This result is perhaps best interpreted as showing the value of different freshwater habitats for wetland plants, as well as emphasising the crucial role of ponds. We also learn from this paper that older women know more about wetland plants than younger men. I hesitate to place interpretations on this observation!

In terms of the services provided by ponds, it’s often asserted that they ‘help to provide clean water’. Clearly this is a very complex area with many processes operating and potentially thousands of different chemicals that could be ‘treated’ by ponds. A detailed review by a French team examines pesticide dissipation in artificial ponds and opens up the black box to look at the different processes involved. The complexity of processes operating at the same time to allow ponds to be effective in pesticide reduction hints at how difficult it would be to harness this process practically at a large scale. Often, the main difficulty with applying nature-based solutions, like pollutant interception ponds, is at the practical implementation stage. Although we can design pond systems that can reduce pollution at the plot or field scale, it is much harder to translate these effectively to whole landscapes. In this case, it might be interesting to compare the cost-effectiveness of ponds used to intercept and dissipate pesticides with the simpler approach, now quite widely adopted in agriculture, of applying fewer pesticides in the first place.

PONDERFUL partners will have noted the work on pond definitions by Meredith Holgerson and colleagues. This team has now further resolved some of the classical assumption about mixing of waterbodies, often regarded as one of the trademark differences between ponds and lakes (Classifying mixing regimes in ponds and shallow lakes). Shallow ponds (<0.74 m) mixed intermittently, with daytime stratification often breaking down overnight due to convective cooling. Ponds ≥0.74 m deep were rarely or never mixed, probably because wind energy was not strong enough to break down the stratification. The researchers found that mixing regimes were highly sensitive to very small differences in size and depth, suggesting it will be difficult to predict the likely stratification regimes of individual ponds, which will depend on specific situation (sheltered, open, well- or sparsely-vegetated, orientation in relation to prevailing winds etc etc). In short, as waterbodies become shallower and smaller, it seems likely that mixing outcomes will be more heterogeneous. This is one of the best-known features of small standing waters.

If any freshwater animal is under threat from climate change it must be the endemic fairy shrimp Chirocephalus sibyllae which is found in just one mountain temporary pond in Central Italy. In a paper published earlier this year by Antonella Carosi and colleagues studies on the ecology and habitat of the species were reported, emphasising its extreme vulnerability. In this situation, one can only realistically conclude that the species is almost inevitably destined for extinction without very direct conservation action. The authors note possible strategies for giving the species a chance of long-term survival including: restriction of hikers and livestock to the area occupied by the pond, even when it is totally dry, with fencing; the creation of a cyst bank in the laboratory to enable the reintroduction of C. sibyllae in the case of extinction; and the identification of suitable biotopes to host C. sibyllae populations, after an appropriate assessment of the risks associated with the introduction of the species into new ecosystems. They also note that detailed studies on the cyst-bank dynamics and functioning (ie size of egg bank, survival time of cysts) could help to elucidate the potential effects of climate changes on the C. sibyllae population. All this careful and detailed work seems crucial if this animal is to have any sort of future.

Some other interesting papers

The final paper I highlight in this report is not about freshwater at all. Further work by Lenore Fahrig and colleagues, this time on forests– the habitat that more than any that epitomises the belief that bigger is better – is very relevant to PONDERFUL.

The team first reminds us that a large number of small forests typically support more biodiversity than a small number of large forests of the same area, implying that small patches are disproportionately valuable for biodiversity conservation. They then demonstrate a global trend of higher deforestation in small than large forest patches between 1992 and 2020. Freshwater biologists won’t immediately use the actual outputs from this work. However, the results are a reminder of the Catalan phrase ‘Al pot petit hi ha la bona confitura’ (the best jam comes in small jars), which reflects the PONDERFUL idea that doesn’t just apply to ponds. They are also a reminder of how hard it is to modify or overturn deeply entrenched ideas – even when evidence is available that suggests new thinking is required.

Practical actions

As most PONDERFUL members will know, the Ramsar Convention is currently debating the adoption of a resolution on enhancing the conservation and management of small wetlands which includes (but is not restricted to) alpine wetlands, ponds, karst wetlands, springs, and temporary/ephemeral streams (see item 18.18 in the draft resolution). This was debated by the Parties to the Ramsar Convention – more than 170 Governments around the world – at the recent Conference of Parties in Geneva and was broadly supported and is now progressing to the next stage. I have picked one example of a text paragraph debated at the meeting to give a sense of how the language of these convention develops. The words shown in strikethrough were deleted in the meeting and you can see the process of Governments making language less demanding. So amongst other things, the resolution “Encourages Contracting Parties to consider actively promote (note the weakening of the language here) the conservation and management of small wetlands in policies, plans, programmes, and other policy instruments via legislation, policies and plans, according to their own national conditions and as part of nature-based approaches to climate change adaptation and disaster risk management, among its other relevance to biodiversity conservation, and human health and well-being;”. It’s well worth reading this in detail: the governments involved have to act on this, so it is some of the strongest policy support for work on ponds and other small waterbodies.

In Uruguay, most artificial ponds are built in rural landscapes to collect freshwater for livestock and for irrigating agricultural crops in times of drought, to guarantee and boost agricultural production. They are generally unappreciated, perhaps due to their small size and artificial nature.

Given gaps in legislation and lack of local knowledge on their general functioning, the management of rural artificial ponds relies on landowners’ and farmers’ criteria. This means that artificial ponds are subject to the different intensities in land use and also to management actions that can differ enormously between farms. Some farms, for example, put in place restrictions on cattle access and measures to protect water quality and native vegetation and fauna. However, on most the prime focus is to secure the ecosystem service for which they were built: water storage. That is why exotic and invasive species, such as carp, are sometimes introduced. Other common practices include the removal of sediment and of littoral vegetation to facilitate cattle access to water.

The potential negative impacts of some management practices, which include higher greenhouse gas emissions, loss of native biodiversity, and facilitation of toxic cyanobacterial blooms, are largely ignored or underestimated.

Within the PONDERFUL project, the Centro Universitario Regional del Este (Universidad de la República, Uruguay) is carrying out investigations on agricultural ponds of contrasting land use intensity. Our group has found striking differences in the richness of aquatic plants among nearby ponds with contrasting land use intensity in their watersheds and consequent contrasting trophic state. Particularly, we have found lower submerged plant species richness in the ponds with high trophic state than in nearby ponds with low or medium land use intensity and low trophic state (see plot below).

In two particular pondscapes (Sierra de los Caracoles y La Pedrera) we also compared ponds where livestock have free access to water with fenced ponds where livestock cannot reach the water – or can only access through small areas. Fencing the perimeter of the ponds to prevent direct access of animals maintains water quality and preserves the area around the edge of the ponds. One of our main findings is that excluding livestock increased aquatic plant richness in the ponds. This fact is illustrated in the pictures below, where we can see ponds with restricted access through fencing (left) and ponds with unrestricted access of livestock to water (right). Pictures above were taken at ponds located in the La Pedrera (Rocha county) demosite, whereas pictures below belong to ponds located in Sierra de los Caracoles (Maldonado county) demosite. Please note in some of the photos the chambers that collect the greenhouse gases emitted by the ponds.

Diverse aquatic plant communities produce many benefits in ecosystems, such as overall higher biodiversity, lower carbon emissions, and higher resilience against external disturbances, among many others.

These results suggest that both land use intensity and local management measures can greatly modify the direction and magnitude of ecosystem services potentially provided by artificial ponds for both people and nature. This research area has enormous importance for the country, as the construction of rural ponds is increasing dramatically in Uruguay.

Uruguayan Team: Maite Colina, Clementina Calvo, Florencia Cuassolo, Leandro Gallo,  Emilia Heber, Constanza Passadore, Franco Teixeira de Mello & Mariana Meerhoff

Approximately 1,000 ecologists from around the world gathered (physically or virtually) at the International Congress of Ecology (INTECOL) from 28 August to 2 September in Geneva, Switzerland, to better understand how we can create a new paradigm to live in harmony with nature.

While ecology as a science will not resolve by itself the desperate challenges that we have created for ourselves it is evident that our society needs ecology to help us manage the biodiversity crisis and the ecosystem services that rely on it, in order to help us guide towards a more sustainable future.

In this framework, the implementation of Nature-based Solutions allows us to address several important societal challenges. This was illustrated in a special session focused on pondscapes organized by PONDERFUL partners (Beat Oertli, Malgorzata Blicharska, Aurélie Boissezon, Maria Cuenca Cambronero and Sandra Brucet). This session focused on how the creation, restoration and management of ponds and pondscapes can efficiently promote biodiversity and offer several Nature Contributions to People. In particular, it explored how these small waterbodies can helps us in our efforts on adaptation and mitigation to climate change.

In this session, some of the PONDERFUL researchers presented the first results related to measurements of NCPs and biodiversity in pondscapes, focusing on case studies from Spain and Switzerland. Others in the team also explained some of the benefits of pondscapes for biodiversity (including pollination), water purification and stormwater retention. Both local and international scales were considered in this session.

Early results on carbon trapping in a Swiss pond

One of the most innovative aspects of PONDERFUL is our research to calculate the carbon balance of ponds by studying both the carbon stored and the carbon released.

At INTECOL, the PONDERFUL team from HES-SO in Switzerland shared some exciting early results of their research on carbon trapping in ponds. Our preliminary results show that ponds may act as powerful carbon sinks.

This included an example of a calculation that has been made for a pond located in the Swiss pondscape “Bois de Jussy”, which is in a woodland near Geneva.

These ponds trapped carbon through photosynthesis of algae and vascular plants and released different gases, which were mainly methane. The quantity was expressed in equivalent CO₂ to take into account the global warming potential of each gas (GWP100).

These encouraging results now need to be consolidated with the carbon balance that is being calculated in all other studied ponds in each of the eight countries in PONDERFUL.

If these initial results are confirmed, there is the potential for pondscapes to be recognised as blue carbon stocks, which could help us to reach our international commitment for green-house gas emissions, set out in the Paris Agreement.

Over the coming months, we will be addressing this important question: in which circumstances does a pond act as a carbon sink? And, in which circumstances does a pond act as a carbon source?

The figure shows an example of carbon balance calculation made one pond in Switzerland thanks to data collected during 2021. Author of the slide: Julie Fahy.

By Beat Oertli & Aurelie Boissezon (HES-SO)

Land use change is one of the most important threats to biodiversity around the world. The effects of land use on biodiversity are most visible at local scales but are not adequately captured on the current global land use mapping. Global land‐use projections have a coarse spatial resolution, which means they do not capture small detail. Therefore, these estimates are unable to meet the needs of local research and decision-making.

In PONDERFUL we were working on two protocols to update the GLOBIO land use allocation model to further downscale land use projections at fine spatial resolution (100 and 10m).

We focused our analysis on Belgium, which, despite its small size, contains a lot of geological variation. Our chosen study area at the local level is Hasselt which has a population of 68,000 and is located 70 kilometres east of Brussels in the Maas-Rhine region of Belgium. Hasselt was selected as the local level study area due to the high conservation value of its ecosystem.

We produced future land use maps with fine scale resolutions (100 and 10 m). Figure below shows land use distribution with a fine resolution of 100 m at national scale in (a) present day (2018) and from a mild to a worst-case scenario, from b to d, respectively, for 2050.

Next figure below shows land use distribution with a fine resolution of 10 m at local level in (a) present day (2020), and from a mild to a worst-case scenario, from b to d, respectively, for 2050. Results from future land use maps show different patterns of land use types under various future scenarios were observed. The second figure below shows land use distribution with a fine resolution of 10 m at local level in (a) present day (2020), and from a mild to a worst-case scenario, from b to d, respectively, for 2050.

Results from future land use maps show different patterns of land use types under various future scenarios were observed.Our results from accuracy assessment indicated that the Globio land use allocation model is capable for downscaling global land use information to the fine spatial resolution at local and national level. Moreover, these high-resolution land use datasets can be effectively used, in conjunction with environmental models, to analyse land use change impacts on biodiversity at finer resolutions than previously possible.

Our next step, which is currently under way, will involve the co-development of scenarios by translating stakeholders’ storylines into maps and quantitative parameterizations.

By Sopan Patil and Parinaz Rashidi (Bangor University)

Nature-based solutions (NBS), as ‘green infrastructure’, are increasingly gaining traction in academia and policy-making as a way to reconcile the objectives of enhancing biodiversity and addressing challenges facing society, These challenges include climate change adaptation and mitigation as well as human wellbeing.

The European Commission considers NBS as key to “achieve more sustainable and resilient societies” and is working to position the European Union (EU) as a global leader in the development implementation of associated projects. However, while NBS are helpful as a common denominator to get people talking about biodiversity and climate-friendly infrastructure, the vagueness of the concept can obscure the fact that not all ecosystems benefit equally from NBS. Afforestation programmes or green roofs and walls, for example, are commonly implemented NBS. Meanwhile, other ecosystems continue to deteriorate in quality and diminish in quantity.

Importantly for the PONDERFUL project, these include Europe’s ponds. In general ponds are ecosystems that are neglected in policy and practice and it is still relatively uncommon to use them as NBS.

Figure 1. Demosite in Geneva, Switzerland by Julie Fahy.

A group of PONDERFUL partners have analysed the policy framework of the EU, assessing what currently limits the implementation of ponds and landscapes of different types of ponds (pondscapes) as NBS.

The group is also identifying potential opportunities contained in this framework. For the policy analysis, the team of researchers from Uppsala University in Sweden and the Ecologic Institute in Germany extracted the key policy mechanisms from 38 policies from a wide range of policy areas and assigned them to seven different common categories of barriers and enabling factors for NBS implementation. These were: objectives & targets, legislation & regulations, management approaches & tools, institutional arrangements, stakeholder awareness & engagement, and knowledge development & transmission.

Importantly, these barriers and enabling factors do not take effect independently from each other, but are strongly interlinked. This means that, together, they represent opportunities and limitations for the implementation of a given ecosystem as NBS.

While results are still preliminary, there are strong indications for the following three key findings.

1. Oportunities at landscape scale – for some ecosystems

In the past, the EU has been accused of incentivising the use of NBS as piecemeal solutions but not encouraging a coherent landscape-wide network of infrastructure that would maximise benefits, especially those related to biodiversity enhancement. Instead, we find that the policies provide a variety of policy mechanisms that increase the opportunities for planning of NBS at landscape scale, as well as for ecosystems that can act as stepping stones to increase habitat connectivity.

Ponds are even specifically mentioned as ‘stepping stones’ in the Habitats Directive. However, the binding regulations concern mostly the enlargement and improvement of the Natura 2000 network of nature protection areas. They shall help to protect and restore the habitats and species contained in the annexes of the Birds and Habitats Directives. While proposed binding restoration targets and linked financing mechanisms are designed to strengthen the Natura 2000 network and its habitats, the political support for ecosystems not listed in the aforementioned annexes, such as ponds, misses ‘legal teeth’. Therefore, unfortunately, for most ponds, only very limited opportunities arise from the push to enhance habitat connectivity through NBS. An exception are Mediterranean temporary ponds that are listed as Natura 2000 habitats of interest.

 2. Climate change adaptation and mitigation

The focus on existing or potentially protected habitats extends to another major NBS-related focus of the EU policy framework – contributing to climate change adaptation and mitigation through NBS.

Specifically, the proposed binding restoration targets would require EU Member States to report on the expected adaptation and mitigation co-benefits of the protection and restoration measures for habitats under the Birds and Habitats Directives.

The EU also pursues enhancing carbon-rich areas more generally. For example, the new Common Agricultural Policy (CAP) prohibits the conversion of peatlands and wetlands to farmland from 2025 onwards, and will provide financial resources for their rewetting. In this context, ponds are, however, not specifically mentioned as prioritised ecosystems. They could though be considered as Natural Water Retentions Measures for flood protection and drought resilience or as part of green infrastructure for wastewater treatment and reuse to reduce energy consumption, next to ensuring water security. The EU encourages such measures in, for example, the Floods Directive.

3. Local stakeholders’ ambition is still critical

While EU policies set an overarching framework for NBS implementation, they also leave up much to the discretion of lower-level authorities and even individual land owners.

For example, the CAP financially incentivises the joint implementation of biodiversity and climate-friendly measures. However, it does not mandate it or even put in place the arrangements to build the necessary capacities. The EU’s Research and Innovation policies, and more specifically Horizon Europe, could play a special role regarding which ecosystems will be implemented as NBS. Projects and missions under this policy could help local stakeholders to plan, design, and implement NBS – as well as contributing to their upscaling.

The research team looks forward to engaging with interested stakeholders on how to make use of existing policy opportunities for the implementation of ponds as NBS, as well as entering a dialogue with the European Commission on how to enlarge or create new opportunities for ponds in the EU’s policy framework. Additionally, the team is keen to assess the role of local policies and practices in the implementation of ponds as NBS in future research endeavours.

By Simon Otis Ryfisch (Uppsala University)

The PONDERFUL project is attracting attention from media around the world and, in recent months, our partners have made a number of appearances on TV and radio.

PONDERFUL collaborators at the University of Applied Sciences and Arts of Western Switzerland (HES-SO) interacted with journalists about their research on carbon sequestration and greenhouse gas emissions on ponds in Geneva. This resulted in the team, led by Professor Beat Oertli, appearing on Radio Télévision Suisse and RTS radio programme CQFD to share their early results. Their research, which they recently presented at INTECOL, was also covered in national newspapers.

In Uruguay, Professor Mariana Meerhoff of University of the Republic appeared on live TV discussing the complex and often controversial issues around artificial ponds, which have been created for agriculture or to provide cattle with water. In a studio interview with science programme SobreCiencia on TV Cuidad she shared how PONDERFUL is helping us to understand more about the relationship between biodiversity, the climate and these small waterbodies.

The Revelator, an online magazine from the Center for Biological Diversity in the US, has also run a feature on PONDERFUL. The journalist interviewed Thomas Mehner from PONDERFUL partner Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Germany, as well as other PONDERFUL partners and leading figures in freshwater ecology.

Jeremy Biggs, CEO of Freshwater Habitats Trust is leading the communication and dissemination for PONDERFUL. He said: “Through PONDERFUL we are aiming to not only further our knowledge of ponds biodiversity and the relationship between ponds and climate, but to increase public awareness of these issues too. That’s why communicating the knowledge we generate is such a vital part of the project”.

“We are still at early stages in our research so it is gratifying to see that the media is already showing so much interest in our work.”

I’m a limnologist: a freshwater ecologist interested in understanding the functioning of ecosystems and their responses to human activities. Ultimately, I aim to help find better ways to protect nature and to highlight the value of nature for us and for itself.

After achieving a Bachelor in Biology in the Universidad de la Republica (Udelar) in Uruguay, I pursued a Masters of Ecology between Udelar and the University of Liverpool in the UK. Under the supervision of the late Professor Brian Moss, I was introduced to the study of shallow lakes ecology. This opened the door to my PhD studies in Aaruhus University, Denmark, where I was fortunate to join the very active ‘Lake Group’ led by Erik Jeppesen. I remain connected to Denmark as an Associate Researcher and the broad international network of collaboration, which started in that period continues today.

Over time, I have moved from studying purely aquatic phenomena to analysing watershed processes, and from focusing in natural ecosystems to social-ecological systems. I now mostly work on the impacts of global change in aquatic ecosystems, from streams to reservoirs, from shallow lakes to artificial ponds. As a scientist, I am particularly interested in the mechanisms that provide resilience to complex systems against stressors and perturbations. As an environmentally concerned citizen, I am also very interested in contributing to policy making and stakeholder involvement.

I lead most of the Uruguayan contributions to PONDERFUL. This involves coordinating a highly motivated, fantastic team of young researchers, who are carrying out their undergraduate theses, masters, PhDs and postdoctoral projects. The team focuses on different aspects of ponds, from GHG fluxes, nutrient dynamics, biodiversity patterns, trophic web structure and ecosystem stability to stakeholder perceptions and involvement.

The PONDERFUL team in Uruguay is focusing exclusively on artificial ponds, most of which have been constructed to support livestock and crop production. The creation of these waterbodies has skyrocketed over the last 20 years following the intensification of agricultural production. Despite their high numbers, we lack knowledge on the ponds’ functioning and their negative or positive contributions to people.

Through PONDERFUL, we’re aiming to increase knowledge to enable better management of these artificial ecosystems. This could increase their value for biodiversity and reduce their negative impacts, due to eutrophication, cyanobacterial blooms, and the introduction of exotic species.

PONDERFUL is a great network of diverse international researchers who share a common ultimate interest: protecting both nature and human wellbeing. Thanks to the combination of ecologists, social scientists, academics and members of the private sector, I hope and expect that the project will increase our fundamental knowledge of ponds and contribute to better management practices and policies.

Many of the PONDERFUL team are long-time collaborators and friends, which makes this challenging endeavor a thoroughly enjoyable experience. Together, we are highlighting how small aquatic ecosystems are crucial for biodiversity and other key processes relevant both for nature itself and for human societies.

A new quick review of some recent research and policy events of interest to freshwater ecologists, which caught our eye and got us thinking – or suggested some practical actions we could take.

Ponds and other small waters

The paper ‘The disproportionately high value of small patches for biodiversity conservation‘, against the widely applied conservation principle that a single large patch has higher value for biodiversity than several small patches of the same total area, it is an important general contribution to the argument that small habitats – like most freshwaters – are important.

Taking a broadly North American view of the role of small waters the paper ‘Vulnerable Waters are Essential to Watershed Resilience in the catchment‘ is useful support for the importance of small waters in a different political/environmental context.

A recent paper, ‘Structural and functional development of twelve newly established floodplain pond mesocosms‘, describing the early post-creation stages of floodplain pond colonisation and development, will hopefully encourage more detailed investigation of floodplain pond functioning.

Pond inventories that properly include Habitats Directive types such as the one in ‘A review of dystrophic lake and pool habitat in Europe: An Irish perspective‘ play an important role in further refinement of protection measures.

In ‘Diatom Red List Species Reveal High Conservation Value and Vulnerability of Mountain Lakes‘, the importance of a high-altitude ponds for algae is highlighted, whereas the importance of fishes in ponds for overall biodiversity is assessed in ‘A trophic cascade causes unexpected ecological interactions across the aquatic–terrestrial interface under extreme weather’. More subtleties of fish effects on pond communities are shown in ‘Community variability in pond metacommunities: interactive effects of predators and isolation on stochastic community assembly‘.

One thing we are learning is that not all ponds are automatically good. In ‘Small artificial impoundments have big implications for hydrology and freshwater biodiversity‘, the potentially damaging role of creating ponds on small streams is discussed. A similar cautionary perspective is provided in ‘Australian farm dams are becoming less reliable water sources under climate change‘. Another recent study in Australia highlights how ‘Improved management of farm dams increases vegetation cover, water quality, and macroinvertebrate biodiversity‘ so might reduce greenhouse gas risks.

Data from Poland in ‘The influence of land use in the catchment area of small waterbodies on the quality of water and plant species composition‘ is useful additional ammunition in the battle for better land use buffers for pond conservation. This work suggests buffers to protect ponds should be 100 m wide!

Some other interesting papers

Earlier this year an important Danish study ‘Three decades of regulation of agricultural nitrogen losses: Experiences from the Danish Agricultural Monitoring Program‘ reported on nitrogen pollution control measures in headwater streams in agricultural catchments. In ‘Threats, challenges and sustainable conservation strategies for freshwater biodiversity‘, papers which will be well-known to the PONDERFUL team are revisited with the most interesting point from PONDERFUL’s point of view being the need to include all freshwater (not just rivers and lakes).

There is a tendency to focus on ‘fixing’ degraded freshwaters when a more pressing, though often less exciting, need is first to stop the decline of what is still in good condition: ‘Mustering the troops toward preventative management in lakes‘.

New calls for measures to protect rivers continue to proliferate. One that caught our eye was ‘Our failure to protect the stream and its valley: A call to back off from riparian development‘. This paper suggests that we need to know a lot more about the pros and cons of floodplain pond restoration. Some useful lessons have already been learnt from a fish perspective as noted in ‘Freshwater fish biodiversity restoration in floodplain rivers requires connectivity and habitat heterogeneity at multiple spatial scales’. This study provides a large-scale evaluation of nursery area creation for riverine fishes on the lower river Rhine.

Professor Jeremy Biggs, Freshwater Habitats Trust

A team of PONDERFUL researchers from Spain, Sweden and Switzerland will discuss how ponds could help us to mitigate against and adapt to climate change at INTECOL2022. The international congress, which takes place in Geneva from 28 August to 2 September, is expected to draw a global scientific audience of around 3,000 people, joining in person and online.

PONDERFUL partners Beat Oertli, Malgorzata Blicharska, Aurélie Boissezon, Maria Cuenca Cambronero and Sandra Brucet will lead a session entitled ‘Ponds and pondscapes as nature-based solutions for adaptation and mitigation to climate change and biodiversity conservation.’ The session will include 17 presentations, covering PONDERFUL findings as well as related research in wetlands and pond ecology.

The PONDERFUL researchers will share how the project is gathering evidence of ponds’ multiple ecosystem services, including carbon storage and climate regulation, water provision and flood control. They will also discuss the benefits of pondscapes to people, including the importance of ponds in leisure and tourism and supporting wellbeing, as well as the policy context of ponds.

Professor Beat Oertli of the University of Applied Sciences and Arts Western Switzerland said: “This symposium will enable us to collect and synthesise new information and present evidence-based examples, from all over the world. This is a unique occasion to join our research efforts and help to demonstrate the efficiency of ponds and pondscapes for enhancing biodiversity conservation, together with mitigation and adaptation to climate change”.