Small standing waters, ponds or (temporary) pools, are among the most threatened ecosystems worldwide. They are disappearing at an alarming rate due to climate change, intensive agriculture, and other anthropogenic pressures, resulting in the extinction of their unique biodiversity.
The European Pond Conservation Network (EPCN), founded in 2004, aims to promote the conservation of ponds across Europe by linking research, conservation practice and science communication. An important part of this mission is the series of international EPCN workshops held every two years.
For the next three years, the organization has elected Zsófia Horváth, head of the Biodiversity and Metacommunity Ecology Research Group at Institute of Aquatic Ecology, as its new president.
The Pond Manifesto developed by EPCN is available in seven languages, with the Hungarian version prepared by the team of HUN-REN CER.
The Hungarian Academy of Sciences has announced its ‘Momentum MSCA’ postdoctoral fellowship for the first time, enabling outstanding researchers to join the work of Lendület research groups for a period of 1–3 years. The MTA-ÖK Lendület Fluvial Ecology RG received seven applications, of which two candidates were awarded postdoctoral positions for three years, starting from 1 January 2026. Ghoufrane Derhy will focus on a trait-based comparison of riverine and lacustrine food webs, while Junyao Gu will investigate the relationship between molecular-based biodiversity and ecosystem functioning (BEF) across multiple trophic levels in Danube plankton communities. We extend our congratulations to the postdoctoral researchers and the hosting lab!
Pollinators receive considerable interest due to their fundamental role in ecosystem functioning and human well-being. Unlike farmlands, studies of urban pollinator-promoting interventions have only started to grow rapidly recently and have not yet been synthesised, hampering all the related policies. To fill this gap, a new study investigated the impacts of pollinator-friendly management compared to conventionally managed urban green spaces.
This research was led by the HUN-REN Centre for Ecological Research in collaboration with 28 European institutes. Published in Ecology Letters, the synthesis examines whether pollinator-promoting interventions have positive effects on vegetation, floral resources, and a broad range of pollinator groups. The findings show that urban pollinator-promoting interventions generally benefit plants and pollinators with taxon-, intervention-, habitat-, and spatio-temporal-specific differences.
The researchers compiled 28 primary datasets, covering 15 years and 12 countries, with 1,051 sampling sites within Europe. They analysed the general effects, as well as the differences between the intervention types, such as abandonment, extensive mowing, flower sowing, and combined practices, and the habitat types, such as parks, grasslands, road verges, and private and public gardens.
General results present mostly positive and never negative effects for pollinator-promoting interventions, while the details are also particularly fascinating. Lead author Dr. Gabriella Süle explains, “Our synthesis underscores the importance of biodiversity-friendly management practices in cities. All of these pollinator-promoting interventions can be applied not only in public spaces but also in private gardens, allotments, green roofs, and balconies, providing opportunities to improve the public perception of insects and taller vegetation with wildflowers.”
Lead author Gabriella Süle (right) and PhD student Virág Németh (left) sampling a sown flower strip in Budapest, Hungary. These colourful, flowering patches provide not only food and nesting resources for pollinators but also an aesthetic attraction for residents. Photo: Márton Kállai
Impacts on pollinators appear to be stronger for flower sowing as intervention, road verges as habitat, and locations in Northwestern Europe. Dr. Viktor Szigeti notes, “Despite all the efforts to harmonise and compile wide-scale datasets, some limitations have become clear, e.g. for certain pollinator taxa (e.g. beetles), regions (e.g. the Mediterranean), and novel interventions (e.g. for ground-nesting insects). A synthesis always holds the potential to guide the next steps: the need is clear for longer-term and larger-scale studies encompassing multiple taxa, interventions, and habitat types, as well as sampling farmlands, cities, and protected areas simultaneously, even globally.”
Head of pollinator monitoring in Budapest, Viktor Szigeti, catching pollinators on a sown flower strip. In many cases, pollinator-promoting interventions are established in public spaces frequently used by residents, such as a traffic intersection. Photo: Márton Kállai
Building on the collective expertise of 38 authors in pollinator ecology, the researchers identified knowledge gaps and proposed concrete actions to make urban environments more favourable for pollinators while also considering wider socio-ecological aspects. Dr. András Báldi notes, “Our synthesis also presents both ecological and socio-economic arguments and highlights potential pros and cons of pollinator-promoting interventions. Our recommendations draw attention to knowledge gaps and offer actions to make specific interventions more favourable primarily for pollinators while also integrating the residents’ needs.”
In the era of climate change and urban expansion, the threats, but also the available mitigation opportunities, make the enhancement of green spaces in urban settlements an urgent priority. To reach the ambitious goal of bringing people, plants, and pollinators together in multifunctional, resilient, and sustainable infrastructures, citizens and stakeholders will need to develop locally adapted, collaborative, and research-informed biodiversity initiatives.
According to researchers at the HUN-REN Centre for Ecological Research, many perennial grasses that had adapted to ‘normal’ drought conditions perished in the open sandy grasslands of the Kiskunság during the extreme droughts that have become increasingly frequent in recent years. There is, however, some reason for hope: grasses growing on north-facing slopes or near woody patches were more likely to survive.
Festuca vaginata and Stipa borysthenica are two of the most drought-tolerant grass species in Hungary. Following the severe drought of 2022, researchers at the Institute of Ecology and Botany, HUN-REN Centre for Ecological Research, chose to study them.
For many years, ecologists have been monitoring changes in the local flora of the sandy grasslands near Fülöpháza in the Kiskunság region, using several hundred permanent sampling plots. In 2022, rainfall was extremely low — even by recent standards — and temperatures were unusually high. The following year, the researchers assessed how native grasses had coped with these extreme weather conditions. The results, recently published in Global Ecology and Conservation, revealed an alarming picture.
The ecologists assessed the proportion of living and dead grasses in 200 randomly selected 4×4-metre plots. They also noted whether each plot was situated on the cooler northern or the hotter southern slopes of the sand dunes, and whether trees or shrubs were present in the immediate vicinity. The researchers hypothesised that grasses growing on north-facing slopes and near woody patches would be more likely to survive extreme drought.
In 85 of the 200 sampling plots, more than 95% of the grasses had died — virtually none survived. In 167 plots, at least half of the grasses were lost. “Although these species are considered drought-tolerant, the dieback was extremely severe — the 2022 drought exceeded even their tolerance,” said Anikó Csecserits, lead researcher of the study.
Grass dieback was significantly lower near woody patches and on north-facing slopes of the dunes. While in completely treeless areas most grasses had died, in plots where at least 20% of the surrounding 10-metre radius was covered by woody vegetation, 80–90% of the grasses survived. This effect is therefore quite substantial.
If even the most drought-tolerant native perennial grasses can no longer withstand prolonged drought, open areas will remain — ready to be colonised by even more drought-resistant non-native invasive plant species, such as Sporobolus cryptandrus or certain cacti. Additionally, annual grasses may spread — these are species that are active in winter or during wetter periods, then die back in summer and persist through drought in the form of seeds. Ecologists at the HUN-REN Centre for Ecological Research warn that the dieback of native species creates ideal conditions for biological invasion.
The CLIMANATRES project aims to support the cross-border coordination of habitat restoration efforts along the Sava and Danube rivers through science-based decision-support tools. One of the project’s lead partners is the HUN-REN Centre for Ecological Research.
Coordinated in Hungary by the HUN-REN Centre for Ecological Research (HUN-REN CER), this international project supports ecological planning in line with the EU’s nature restoration objectives and the anticipated impacts of climate change. The initiative aims to contribute to the restoration of natural habitats and to enhance landscape resilience in the face of future environmental challenges. In addition to HUN-REN CER, professional partners from five other countries — Slovenia, Romania, Bulgaria, Croatia and Serbia — are also involved in the project.
The project brings together research institutions, nature conservation bodies at local, regional and national levels, as well as forestry planning authorities. Their collaboration aims to promote ecologically informed landscape management and restoration that will enable landscapes to continue supporting the well-being of wildlife — and, through the ecosystem services they provide, the well-being of people — even under the pressures of climate change.
As part of the collaboration, freely accessible online maps and databases will be developed to provide broad, user-friendly support for local and regional ecological restoration planning — and thereby also assist in implementing the EU Nature Restoration Regulation. The maps will indicate the suitability of specific sites for various habitat restoration objectives — such as habitats of community interest or ecological corridors.
As part of the project, researchers and partners will develop five climate-informed action plans aimed at improving the ecological connectivity and natural condition of the Sava and Danube river corridors.
The public launch event of the CLIMANATRES Danube Interreg project was held on 21 July in Vácrátót, at the Institute of Ecology and Botany of the HUN-REN Centre for Ecological Research. Further details about the event and the project are available on the official websites of the institute and the project.
Villages, often separated from larger towns and cities, consist of clusters of households and a few public buildings. Despite their long history, the biodiversity of European villages has been understudied compared to urban areas, forests, grasslands, or agricultural fields. A new study reveals their biodiversity potential and how nearby landscapes influence biodiversity patterns and human well-being.
This research was led by an international team from the HUN-REN Centre for Ecological Research with 20 other institutes contributing from Hungary, Romania, Germany, and Italy. Published in Nature Sustainability, the study examines how landscape complexity and proximity to cities affect village biodiversity and socioeconomic conditions. The findings show higher biodiversity in villages within forest-dominated landscapes compared to agricultural settings, while city proximity boosts human well-being.
The researchers surveyed biodiversity in 64 villages around 16 mid-size cities in Hungary and Romania. Half of the villages were near cities, the other half farther away, and were either in agriculture- or forest-dominated landscapes. The team conducted botanical surveys, used pitfall traps for ground-dwelling arthropods, employed D-vac suction sampling for vegetation-dwelling arthropods, and set trap nests for cavity-nesting bees and wasps, as well as point counts for birds.
Project leader, Péter Batáry, working with D-vac insect suction sampler in the centre of village Salköveskút, Hungary. The samples revealed significantly higher vegetation-dwelling arthropod species richness at village edges compared to centres, especially in forest-dominated landscapes. Photo: Attila Torma
They documented 1,164 species across nine taxonomic groups. Multitrophic diversity, a measure of overall biodiversity, was 15% lower in villages surrounded by agricultural fields than by forests. Lead author Dr. Péter Batáry explains, “This underscores the importance of landscape-wide species pools in shaping village biodiversity. City proximity had little impact on species numbers and overall diversity, suggesting other factors have a greater influence.”
The team also collected socioeconomic data for Hungarian villages to calculate the Better Life Index, reflecting human well-being through living conditions and quality of life. The Better Life Index was 27% higher in villages in the agglomerations of cities and 14% higher in villages in forest-dominated landscapes than those in agricultural ones. Co-author Dr. Katalin Szitár notes, “Proximity to urban areas brings better access to services, while forested landscapes offer cleaner air and more green spaces, enhancing living standards and quality of life.”
Village edge of Botfa, a village embedded in a forested-dominated landscape near the city, Zalaegerszeg, Hungary. Proximity to the city was associated with higher human well-being without reducing biodiversity, despite increased human footprint. Photo: Tamás Lakatos
Using GIS, the researchers measured the Human Footprint Index (HFI) to assess environmental impact from infrastructure and land use. Villages with a higher Better Life Index also had a higher HFI, especially near cities, indicating that better living standards can increase environmental impacts. A higher HFI was linked to lower multitrophic diversity, revealing a trade-off between human development and biodiversity. However, forest-dominated landscapes maintained higher biodiversity despite increased human activity, suggesting complex landscapes can mitigate biodiversity loss. Dr. Edina Török notes, “Our findings highlight the delicate balance needed to enhance human well-being without compromising the ecological health of rural landscapes.”
To be effective, sustainable village management should integrate landscape context into development plans. For villages near cities, minimizing soil sealing and green infrastructure intensification can help protect biodiversity. In villages predominantly surrounded by forests, limiting agricultural expansion is crucial. Increasing the connectivity of villages centres with forests and upgrading green infrastructure in agricultural areas can boost biodiversity and well-being. Collaboration between residents, authorities, and landowners, combining policy-driven and community-driven actions, is vital. Dr. Péter Batáry emphasizes, “The EU Rural Development Strategy should prioritize biodiversity management to improve conservation and landscape quality in and around villages.”
Lead photo: Várda is an example of a village embedded in an agriculture-dominated landscape, where multitrophic diversity was 15% lower on average than in forested landscapes.
The Restoration Ecology Research Group of HUN-REN, CER-IEB conducted long-term monitoring of vegetation changes over a period of 17 to 25 years at three restoration experiments in the Kiskunság, Hungary. These sites underwent different restoration treatments, including native seeding, mowing, and carbon amendment. The study aimed to examine how these interventions influence the abundance of annual and perennial invasive alien plants over time, and how invasion dynamics are shaped by propagule pressure within a 100-meter buffer.
The findings were encouraging for annual invaders: their cover generally declined over time, particularly in areas where native seeding was applied. Seeding proved to be the most effective method in controlling these short-lived, fast-spreading species. In contrast, the situation was quite different for perennial invaders. These species consistently increased in cover over the decades, regardless of the type of intervention or the amount of invasive propagule pressure within a 100-meter buffer.
Monitoring arrangement for estimating invasive propagule pressure with transect method. Established eight 100-meter-long transects towards the eight cardinal directions and recorded the number of shoots of each invasive species in 1 m x 1 m adjacent plots along each transect.
Unexpectedly, local propagule pressure had little influence on invasion trends, suggesting that larger-scale processes and long-distance dispersal play a more dominant role. Mowing, although commonly used to control invasive species, may inadvertently aid invasive species by creating “colonisation windows” for opportunists already present in the landscape.
The authors stress that current restoration methods are insufficient to tackle the long-term threat of perennial invasive species. Once established, these plants are notoriously hard to remove, and their increasing dominance can threaten native biodiversity and restoration success. Therefore, more targeted, proactive strategies are needed—ones that take into account the life history traits and dispersal mechanisms of problematic perennials.
In conclusion, the study calls for a shift from site-level restoration to broader, landscape-scale approaches. Successful restoration must consider not only conditions within the restoration site, but also the surrounding ecological context, including propagule availability, disturbance regimes, and the resilience of native plant communities.
Niels Bohr, the Nobel laureate in Physics and father of the atomic model, is famously supposed to have said, “It is difficult to make predictions, especially about the future.” Our uncertainty about whether he actually said this or not, some attribute the quote of the legendary baseball player (and philosopher) Yogi Berra, highlights that making predictions about the past can be equally challenging. However, reconstructing the distant past and tracing how and when life adapted to new conditions, such as the rise of oxygen on Earth, requires making exactly such predictions.
“In a recent study published in Science, a multinational collaboration led by Gergely Szöllősi, senior research associate at HUN REN’s Institute of Evolution and the head of the Model-based Evolutionary Genomics Unit at the Okinawa Institute of Science and Technology (OIST), Tom Williams’ lab at the University of Bristol and Adrian Davin from Phil Hugenholtz’s group at the University of Queensland constructed a detailed timeline for bacterial evolution and oxygen adaptation, with a specific focus on how microorganisms responded to the Great Oxygenation Event (GOE) some 2.33 billion years ago. This event, triggered in large part by the innovation of oxygenic photosynthesis in cyanobacteria, fundamentally changed Earth’s atmosphere from mostly devoid of oxygen to one where oxygen became relatively abundant. Until now, establishing accurate timescales for how bacteria evolved before, during, and after this pivotal transition has been hampered by incomplete fossil evidence and the challenge of determining the maximum possible ages for microbial groups—given that the only credible maximum for the vast majority of lineages is the Moon-forming impact 4.52 billion years ago, which likely sterilised the planet.
The researchers addressed these gaps by turning to the geological and genomic records in tandem. Their key innovation was to use the GOE itself as a temporal constraint, assuming that most aerobic (oxygen-using) bacterial lineages are unlikely to be older than this event—unless fossil or genetic signals strongly suggest an earlier origin. They introduced a Bayesian approach that uses this assumption as a “soft” maximum, allowing for exceptions where the data warrant it. This approach, however, requires making predictions about which lineages were aerobic in the deep past. To do so, the team deployed machine-learning algorithms that aggregate signals across the entire genome, thereby robustly inferring oxygen tolerance from incomplete ancestral gene repertoires. To best leverage the fossil record, they incorporated genes from mitochondria (branching with Alphaproteobacteria) and chloroplasts (branching with Cyanobacteria), enabling additional fossil-based calibrations from the eukaryotic record and thereby improving dating accuracy.
Their results indicate that at least three aerobic lineages appeared prior to the GOE—by nearly 900 million years—suggesting that a capacity for using oxygen evolved well before its widespread accumulation in the atmosphere. Intriguingly, these findings also point to the possibility that aerobic metabolism may have predated the evolution of oxygenic photosynthesis. For instance, the earliest inferred aerobic transition occurred around 3.2 billion years ago in the common ancestor of two cyanobacterial groups, indicating that the ability to utilise trace oxygen may have facilitated the later emergence of genes central to oxygenic photosynthesis. Moreover, the study estimates the last common ancestor of all modern bacteria lived sometime between 4.4 and 3.9 billion years ago, in the Hadean or earliest Archaean era. Major bacterial phyla are placed in the Archaean and Proterozoic eras (2.5–1.8 billion years ago), while many families date back to 0.6–0.75 billion years ago, overlapping with the era when land plants and animal phyla originated.
Notably, once atmospheric oxygen levels rose during the GOE, aerobic lineages diversified more rapidly than their anaerobic counterparts, indicating that oxygen availability played a substantial role in shaping bacterial evolution. The researchers argue that this combined approach of using genomic data, fossils, and Earth’s geochemical history brings new clarity to evolutionary timelines, particularly for microbial groups that lack a straightforward fossil record. It also offers a powerful framework for exploring how other microbial traits arose and interacted with the planet’s shifting environment across geological time.
Photo: Banded Iron Formation (BIF): sedimentary rocks that record the rise of atmospheric oxygen during the Great Oxidation Event (GOE)
A new research project started in the HUN-REN Centre for Ecological research titled „Increasing the ecological sustainability of oak forests by close-to-nature forestry based on experimental research (#oakadapt)”. The project is founded by the Interreg Slovakia-Hungary Programme. It is based on a collaboration between Slovakian and Hungarian research and forest management organizations, the leader of the consortium is the Technical University in Zvolen. The scientific leader of the project in the HUN-REN Centre for Ecological Research is Dr. Péter Ódor.
Central European oak dominated forests have been used for centuries and currently exhibit serious biodiversity decline associated with global environmental changes. Nonetheless, they preserve considerable natural capital. They have a key role in the timber provisioning for the society, protection of forest biodiversity and recreational purposes. They have a large potential in mitigation of climate change, protection of soil and water. Forest management has high responsibility in the sustainable use of forests, integration of protection elements and resilience against climate change. Developing sustainable management approaches that increase the resilience of forests and support biodiversity are central in current applied ecological research. Scientists from the Technical University in Zvolen (SK) and the HUN-REN Centre for Ecological Research (HU) experimentally investigate the effects of different forestry interventions and gap-cutting characteristics on forest microclimate, biodiversity, tree growth, and regeneration. Within the project, they will continue their experiments, make comparisons between forest stands managed by continuous cover forestry and rotations forestry, produce scientific research papers and transform the results into the forestry practice for local management partners: Forests of Krupina City (SK) and the Pilis Park Forestry Company (HU). This research can contribute to the scientific basis of continuous cover and close-to-nature management systems, that are used by the manager partners on large forest area. In addition, new management guidelines for ecologically sustainable forestry will be prepared in cooperation with National Forest Centre (SK) and Real Forest (SK) organizations. Pilis Park Forestry Company will develop and introduce the administration system of gaps and gap management, as well as introduce a monitoring of game browsing for successful forest regeneration. National Forest Centre will provide service for data sharing and information reflecting favourable status of forest biodiversity before global environmental changes. Such information and databases will support knowledge-based decision-making and partner’s cooperation. Results of the project will be widely disseminated among stakeholders, including education, nature conservations and forestry sector and provide important example and reference for future climate smart forestry.
Project information:
ID: HUSK/2302/1.2/168
Lead researcher: Ódor, Péter
Planned duration: 2024-2027
Amount of support: 336.000 EUR
EU contribution: 268.800 EUR
National contribution: 67.200 EUR
Founding organization: Interreg Slovakia-Hungary
Predicting and mitigating the effects of climate change while preserving biodiversity is a top priority for both scientists and policymakers. As climate change intensifies, leading to more frequent and severe droughts, understanding the impact on natural ecosystems has become increasingly important. One of the main challenges is forecasting changes in species richness due to shifts in precipitation patterns. While it’s established that, on a broad geographic scale, regions with more water generally support greater plant diversity, results vary at smaller plot levels concerning how rainfall affects species richness. To improve predictions, it’s essential to explore the underlying mechanisms – particularly how intense droughts and long-term rainfall changes impact biodiversity. A new study shows that increased aridity at the plot level is indeed linked to a decrease in plant species richness, and this connection is even more pronounced following extreme droughts. However, this phenomenon is not easy to detect because in the absence of drought, dominant plant species can obscure this effect.
The study, carried out by the HUN-REN Centre for Ecological Research in Hungary, examines the intricate connections between long-term changes in rainfall, extreme drought conditions, the biomass of dominant plant species, and plant species diversity in a dryland ecosystem. Published in the Journal of Ecology, the research reveals that increased dryness leads to a reduction in plant species diversity in drylands and uncovers the mechanisms through which rising aridity contributes to biodiversity loss in these fragile ecosystems.
The experimental area in Fülöpháza, Central Hungary. Chronic precipitation treatments (along with decreasing aridity: severe drought, moderate drought, control and water addition) simulates changes in precipitation that have occurred several times historically. The image shows severe drought management, which excludes all rainfall from late June to late August. Prior to chronic treatments, half of the plots were exposed to an extreme treatment which simulated a drought unprecedented since the beginning of regional measurements.
Using data from a seven-year climate change field experiment, researchers conducted a path analysis to examine how precipitation influences species diversity, both directly and indirectly. The experiment simulated an extreme drought event followed by long-term variations in summer rainfall with the use of rainout shelters. Initial analysis showed a strong positive relationship between rainfall and species diversity after extreme drought treatment, but this effect was absent without drought. Interestingly, the path analysis uncovered another layer: in the absence of drought, increased rainfall boosted the biomass of dominant grass species, leading to a decrease in overall plant diversity. Nevertheless, the direct effect of rainfall remained positive, enhancing species richness even when dominant species exerted a suppressive impact. Additionally, the study revealed that past extreme droughts strengthened the link between rainfall and species diversity. Lead author Dr. Gábor Ónodi explains, “Extreme droughts decrease plant species richness and weaken dominant species. The reduction in the biomass of dominant species allows other plants to colonise, potentially altering the plant community.”
These findings have significant implications for predicting how natural ecosystems will respond to future climate change. Dr. György Kröel-Dulay, the lead researcher of the field experiment, notes “As global temperatures rise and precipitation patterns become more extreme, ecosystems may become increasingly sensitive to changes in water availability.” The study underscores the importance of considering both direct and indirect effects when evaluating the impact of climate change on biodiversity. Senior author Dr. Zoltán Botta-Dukát adds, “By deepening our understanding of these dynamics, we can better anticipate upcoming challenges and develop more effective strategies for conserving biodiversity in a world facing growing environmental uncertainties.”
Urbanisation is rapidly transforming landscapes worldwide, becoming a key driver of global biodiversity loss. It often impacts biodiversity negatively by creating selective environments that limit species diversity in urban compared to natural habitats. Amidst this challenge, understanding and enhancing urban blue-green infrastructure is critical. Garden ponds are small yet significant water features that are increasingly common in urban areas. They offer numerous ecosystem services, like aesthetic purposes, microclimate regulation, and habitats for ornamental species. However, their role in supporting biodiversity is still largely unknown.
A recent countrywide citizen science project called MyPond launched by researchers from the HUN-REN Centre for Ecological Research in Hungary highlights the potential of garden ponds as crucial contributors to urban biodiversity. The online survey gathered data from over 800 garden pond owners, uncovering insights into how these small water bodies support various animals, including amphibians and their tadpoles, odonates, and birds. The study also examined the impact of pond features, pond management practices, and urbanisation on the occurrence of these animals, shedding light on the role of pond management for wildlife.
“Our findings revealed that key pond features such as pond age, area, aquatic, and shoreline vegetation all have a strong influence on the occurrence of the studied animals. Amphibians and their tadpoles, odonates, and birds were less likely to be present in or at newly installed ponds (0-1 year), which can be due to the lack of vegetation and sediment that could offer hiding and breeding places. Aquatic vegetation was positively associated with the presence of tadpoles, odonates, and birds which indicates the habitat structuring role of aquatic vegetation that benefits biodiversity. Conversely, algaecide addition negatively affected the presence of amphibians and their tadpoles. Ponds in strongly urbanised areas had less sightings of adult amphibians and their tadpoles, while these types of ponds were visited by more odonates and birds. Despite these challenges, garden ponds emerged as vital refuges for wildlife, hosting a total of 13 amphibian species across the country, and providing critical secondary habitats within urban landscapes.” – explains Dr Zsuzsanna Márton, first author of the study.
Beyond biodiversity, the study also highlighted the ecological importance of garden ponds and provided actionable insights for urban biodiversity conservation, encouraging thoughtful pond management and design to maximize their benefits.
“Our study demonstrates that citizen science is a powerful tool for urban planning, as it can contribute to gathering valuable data on urban biodiversity and utilise it for more efficient conservation strategies. It could help urban planning by identifying hotspots of aquatic biodiversity or critical areas for the conservation of key groups like amphibians in urban environments. Garden ponds might provide important stepping stones, connecting other aquatic habitats in the landscape. Also, participants may become more conscious of environmental issues and their role in it which might lead to more active engagement in supporting blue-green infrastructure development.” – summarises Dr Zsófia Horváth, the senior author of the study and head of the Biodiversity and Metacommunity Ecology Research Group at Institute of Aquatic Ecology, HUN-REN Centre for Ecological Research.
Viktor Szigeti, a research fellow at the Institute of Ecology and Botany of HUN-REN CER, has been awarded a grant from the STARTING sub-programme of the National Research Excellence Programme, for the research project “Flowers and pollinators for buzzing cities”. The main objective of the STARTING sub-programme is to provide funding for postdoctoral researchers to start their independent research careers and to strengthen research creativity and excellence. (The National Research Excellence Programme replaced the previous OTKA calls in 2024.)
The 4-year research grants will be used for research on pollinating insects, as outlined below.
Pollinators play a fundamental role in nature and human life. Nowadays, the pressure to protect pollinating insects is shifting from farmlands to cities. They can be supported by maintaining semi-natural habitats and introducing novel techniques, such as less frequent mowing, flower sowing, and bee hotels. Through these interventions, cities could offer diverse environments, benefiting both pollinators’ and human well-being. However, the lack of evidence for novel solutions may trigger counterproductive ‘bee washing’ processes. Ecological research on urban pollination is in the spotlight with outstanding public interest. Therefore, researchers, local and (inter)national authorities are under pressure to develop and monitor pollinator-promoting interventions.
Our project aims to study urban pollinators by five priorities:
1) Explore the effectiveness of pollinator-promoting interventions;
2) Disentangle local and landscape-scale factors;
3) Develop simple sampling methods;
4) Investigate microclimate dependencies; and
5) Work on European and global-level syntheses.
To achieve these, we are monitoring flowers and pollinators in parks, road verges, and ‘bee pastures’ (in Budapest from 2021); developing novel interventions and a citizen-science mobile application; collaborating in EU-level research. These studies also embrace the ambitious vision of creating multi-functional, resilient, and green infrastructures. Overall, we are a small but emerging team, looking forward, challenging boundaries, and exploring innovative solutions for urban pollinators. This grant offers the opportunity to share captivating stories of cities buzzing with people, flowers, bees and butterflies.
Tropical forests, often referred to as the “lungs of the Earth,” are essential for sustaining life on our planet. They provide clean air, water, and unparalleled biodiversity. While deforestation due to slash-and-burn agriculture, mining, and logging remains the most recognized threat, less visible but equally dangerous forces are at work. A new study reveals that nutrient enrichment – driven by human activities such as agriculture and fossil fuel combustion – poses a significant risk to the delicate dynamics of tropical forests.
The research, conducted by an international team of scientists from the University of Kaiserlautern-Landau (RPTU), the University of Applied Sciences and Arts Goettingen, and the HUN-REN Centre for Ecological Research in Hungary, focuses on how nutrient deposition affects tropical tree seedlings’ growth and biomass accumulation. Their findings, published in Current Forestry Reports, show that this phenomenon can potentially disrupt forest composition and resilience, particularly in the face of global climate change.
By synthesizing data from 59 studies conducted across tropical regions worldwide, the researchers employed meta-analysis to uncover broad patterns of nutrient effects. Their analysis revealed that nutrient addition significantly boosted tree seedling growth, with shoot biomass increasing by an average of 26% and growth rates by 14%. Notably, the combination of nitrogen (N), phosphorus (P), and potassium (K) produced the most pronounced effects, driving growth rate increases of up to 27%. These impacts were particularly pronounced in seasonally dry sites, where growth rates surged by 38% and shoot biomass by an impressive 70%. Lead author Dr. Daisy Cárate Tandalla explains, “NPK are fundamental nutrients for plant growth. However, many tropical soils are nutrient-limited. Adding these nutrients disproportionately benefits fast-growing, competitive species, potentially shifting forest composition.”
The team, led by Daisy Cárate Tandalla (centre), working with tree seedlings for a transplantation experiment in the San Francisco Reserve, Ecuador, 2013.
Human activities are dramatically altering natural nutrient cycles. While volcanic activity and wildfires have historically contributed to nutrient deposition, agriculture and fossil fuel burning have intensified and expanded this process to even the most remote tropical regions. These nutrient inputs can give a competitive edge to certain tree species, leading to homogenized forests with fewer species – a trend that threatens biodiversity and ecosystem stability. Senior author Dr. Péter Batáry warns, “These changes may reduce species diversity across entire food chains and weaken forest resilience in the face of climate change. The loss of diversity also diminishes the forests’ ability to adapt to environmental stressors.”
The study also highlights the complexity of tropical forest research. Co-author Dr. Jürgen Homeier from the University of Applied Sciences and Arts Goettingen notes, “The studies we reviewed used a mix of methods – greenhouse pot experiments, transplantation trials, and in-situ fertilizer applications. Identifying seedlings to the species level remains a significant challenge due to the extraordinary diversity and similarity of young tropical trees.”
The dedicated effort of transplanting tree seedlings in the tropical montane forest.
The findings underscore the need for urgent attention to nutrient management in tropical regions. While nutrient deposition may seem like a localized issue, its impacts ripple through global ecosystems, affecting biodiversity, carbon storage, and the planet’s overall health. Tropical forests are a cornerstone of life on Earth, and preserving their complexity and resilience is crucial. This study is a timely reminder that even remote human activities can have far-reaching consequences for the natural world.
Researchers at the HUN-REN Centre for Ecological Research in Hungary applied an outdoor experimental setup of artificial ponds (mesocosms) to simulate habitat fragmentation and found that it significantly reduces microbial biodiversity, particularly among unicellular microeukaryotes. The study also highlights that fragmentation not only affects biodiversity but also disrupts essential food web interactions, underscoring the importance of maintaining connectivity among habitats to preserve biodiversity and ecosystem functioning.
In the midst of the ongoing global biodiversity crisis, even the smallest habitats like ponds demand our attention. Fragmentation of these habitats—driven by human activities like urbanization, agriculture, and land-use changes—poses a significant threat to biodiversity. Often overlooked in conservation efforts, ponds serve as vital ecological hotspots, supporting diverse species and sustaining essential ecosystem processes. These waterbodies are home to various microbial communities that, despite their tiny size play an indispensable role in ecosystem functioning, acting as primary producers, decomposers, and links in food webs. While the impacts of habitat fragmentation on large organisms like mammals and birds are well-documented, the effects on microscopic organisms, including bacteria, algae, and other unicellular eukaryotes remain poorly understood.
A recent study carried out by researchers from HUN-REN Centre for Ecological Research in Hungary explored the effects of connectivity loss within pond networks. Using an outdoor experimental setup of artificial ponds (mesocosms), the researchers simulated fragmentation by terminating the movement of water and organisms between habitats in half of the pond networks while maintaining dispersal in the other half. By controlling for factors like habitat size and environmental conditions, and focusing solely on connectivity loss, the study provided an insight into the direct impacts of fragmentation on biodiversity.
“Our findings were particularly striking for unicellular microeukaryotes. Connectivity loss led to significant declines in their diversity at both local and regional levels, highlighting that fragmentation can directly drive biodiversity loss, even under controlled circumstances. Both rare and abundant species were impacted, suggesting that fragmentation represents a widespread and severe threat to microbial biodiversity. In contrast, prokaryotes appeared more resilient, though we observed signs of a potential “extinction debt,” where biodiversity loss may emerge over longer timescales.” – explains Dr. Beáta Szabó, the first author of the study.
Beyond biodiversity, the study also highlighted how connectivity loss disrupts trophic interactions. Zooplankton grazers, which interact closely with microbial communities, experienced reduced biomass in fragmented habitats, further exacerbating the decline in diversity and community evenness of microeukaryotes. These findings highlight the interdependence of organism groups within ecosystems and the cascading impacts that habitat fragmentation can have on biodiversity and ecosystem functioning.
“Our study clearly demonstrates that habitat fragmentation—specifically the loss of connectivity—can have serious and far-reaching consequences for biodiversity. Even when habitat size or environmental conditions remain constant, simply disrupting the dispersal of individuals between habitats can trigger significant declines in microbial diversity. Conservation efforts must not only focus on preventing habitat destruction, particularly in vulnerable ecosystems like pond networks, but also prioritize maintaining and restoring connectivity between habitats to protect the ecosystems and species that rely on them. This is especially crucial for microbes, which, despite their small size, have enormous ecological significance.” – summarizes Dr Zsófia Horváth, the senior author of the study and head of the Biodiversity and Metacommunity Ecology Research Group at Institute of Aquatic Ecology, HUN-REN Centre for Ecological Research.
The invasive mosquito species, the tiger mosquito (Aedes albopictus), poses significant threats to human and animal health due to its ability to spread over large geographic areas and act as a vector for numerous pathogens. Understanding the ecological relationships this species establishes in different locations is crucial for assessing its worldwide dispersion success and its role in disease transmission. To uncover how invasiveness couples with the ability to adapt to various food sources László Zsolt Garamszegi from the Institute of Ecology and Botany, Centre for Ecological Research, Hungary performed a meta-analysis of published blood-meal surveys.
The analysis included data from 48 independent studies, providing a comprehensive overview of the mosquito’s feeding behavior across different regions and stages of invasion. The results indicate that the tiger mosquito exhibits significant variability in host selection depending on the geographic location and stage of invasion. Importantly, host diversity was greater in the invasive range than in the native range, but in newly invaded areas, the mosquito tends to have a narrower host range than in the long-established populations.
Literature survey and meta analysis of blood-feeding patterns in Aedes albopictus. Invasive Ae. albopictus has considerable ecological flexibility. The species’ ability to adapt to various food sources goes hand in hand with its successful worldwide dispersion, which has strong implications for its role in pathogen transmission.The results have strong implications for how the tiger mosquito mediates host-parasite dynamics in natural systems. Wider host diversity in the invasive range indicates that the chances for the species to act as a bridge vector between distantly related hosts such as humans and birds is higher than in the native distribution range, and this risk enhancing the spread of diseases further increases if the species has more time to adapt to the ecological conditions experienced in a given invaded region. Therefore, the obtained results can align with the ecological foundations that make this species a widespread disease vector worldwide.
The HUN-REN Centre for Ecological Research organised a workshop on ‘The role of ecological monitoring in understanding Hungary’s key environmental problems and developing evidence-based solutions’ on 2 September 2024. The meeting was attended by 75 participants, including researchers from HUN-REN CER and several research institutions and universities, representatives from the Hungarian Research Network (HUN-REN) Headquarters, and partners from the fields of public nature conservation, public health, water, forestry, NGOs and private companies.
During the morning programme, Director General László Zsolt Garamszegi first presented the mission and the strategic concept of the public monitoring programme of the Research Centre. Ecological monitoring is a scientific activity for public purposes, in which socially, economically and environmentally important phenomena are monitored regularly. The aim is to identify and prevent harmful effects on society, the economy, and the environment as soon as possible, and to support positive processes by analysing and interpreting the data collected. The ecological monitoring activities of the HUN-REN CER mostly cover key gaps that cannot be filled by the programmes of public bodies and cannot be adequately covered by data. We have country-wide monitoring programmes and monitoring systems that operate on a regional basis, but there is also the potential to extend the know-how to a national level. Some of these programmes monitor the status of entire ecosystems, while others focus on specific groups of organisms or species that are key for environmental, social, and economic reasons. The programmes address key areas of relevance to the public sector, specific sectors and society and provide science-based answers to important practical questions.
You can read more about our monitoring programmes here: https://ecolres.hun-ren.hu/tarsadalom/#kozcelu.
During the morning Tamara Szentiványi presented the Mosquito Monitor programme, Péter Ódor and Ferenc Horváth the Forest Reserve Monitoring programme. The three sub-programmes of the River Water Monitoring Programme were then presented by the researchers: Pál Boda presented on the monitoring of drying small rivers, András Abonyi on the monitoring of large rivers, and Erika Juhász on the monitoring of beavers. During the afternoon workshops, the professional discussion continued along these main themes. The topics of the three workshops were: River water monitoring programme – water scarcity, biodiversity crisis, human-wildlife conflicts; Strategic issues in forest reserve monitoring; Mosquito monitoring programme – epidemiological aspects and mosquito control practices. One of the main lessons of the workshop was that cooperation between the public and private sector, and the research community is essential to tackle the environmental problems of our time.
The first pan-European study of its kind (Keith, H., Z. Kun, S. Hugh et al. 2024 – nature, communications earth & environment) calculated that Europe’s existing forests could sequester up to 309 megatons of carbon dioxide per year for 150 years if the use of these forests were abandoned and we let them continue to grow and re-grow.. This is equivalent to the CO2 reduction rate targeted in the European Green Deal for the LULUCF sector by 2030 (310 Mt/ha) and is greater than the current level of sequestration of managed forests in Europe (289 Mt/ha).
The authors calculated the amount of carbon stored in above-ground, below-ground and dead biomass from survey data on 288,262 trees in the remaining European primeval and old-growth forests in 27 countries, on 7,982 plots.
Surveyed primary and old-growth forest stands on Europe’s forest cover map
The carbon stocks and carbon sequestration capacities of naturally functioning primary and old-growth forest ecosystems composed of native trees are essential benchmarks. The authors calculated this benchmark forecological zones and forest types, ranging from low-productivity alpine birch forest in Sweden to the highest productivity mixed spruce-fir-beech forests in Bosnia-Herzegovina. Based on this, the predicted carbon carrying capacity of primary and old-growth forests is 22,449 MtC compared to 9,790 MtC in managed forests.
Aboveground carbon stock per hectare – Hungarian data are in the group of “Temperate continental forest – broadleaf” (case numbers are given in the columns)
The GlobBiomass and GeoCarbon projects have so far significantly underestimated forest carbon stocks in all forest types compared to data from primeval and old-growth forest.Therefore global models and parameters need to be developed and revised. Analysis of the tree density, diameter distribution and biomass of standing trees has shown that the thickest trees play the largest role in carbon storage, as half of all biomass is stored in trees thicker than 60 cm.
Tree density (light green) and carbon stock (dark green) of primary and old-growth forests by diameter class with the profile of cumulative biomass (red curve)
The protection and restoration of primary and old-growth forests are therefore not only of paramount importance for the conservation and maintenance of biodiversity, but also have an increasing role in mitigating climate change through their huge carbon sequestration and storage potential.
Researchers of the HUN-REN Centre for Ecological Research also contributed to the pan-European study with recent survey data of forest reserves representing the natural conditions of the Carpathian Basin.
The survey of forest reserves is supported by the public monitoring programme of HUN-REN Centre for Ecological Research and the Ministry of Agriculture.
Slide photo: Beech forest remnant in the Kékes Forest Reserve (Photo: Attila Bíró)
There is a lot of debate about how and why simple multicellularity emerged many times independently and what factors contributed to its prevalence. There are many theories why it was advantageous to be multicellular. Factors with direct advantage for aggregation (like avoiding predation) are evident but there are factors with indirect advantages, like spatiality and a changing environment. The latter can ensure the survival of the cooperative trait through group selection, without kin recognition or selection towards larger size (predation). Researchers of HUN-REN Centre for Ecological Research, Institute of Evolution and ELTE University investigated this hypothesis. They have modelled two types of cells in a temporally heterogenous, spatial environment. Cooperators can associate to form aggregates while cheaters cannot by themselves stick to others but can enjoy the benefits of the aggregate. In resource-rich environments, cooperators have a disadvantage due to slower growth, but only they can create propagules in resource-poor environments. Cheaters therefore need to piggyback propagule-forming cooperators to make it to the next rich habitat. The researchers have successfully demonstrated in their publication published in PLOS Computational Biology that cooperators can survive due to aggregation and group selection, enabled by spatiality in an alternating environment, without any further mechanism needed, like predation.
The evolution of multicellularity is one of the major transitions in evolution. It has occurred independently more than 25 times across different branches of life. Complex multicellular organisms, such as humans, achieve high complexity through related cells that remain together during division. In contrast, most single-celled organisms lack the regulatory mechanisms needed for this. For them, a simpler path is typically viable: forming multicellular structures temporarily, often under stressful conditions, like starvation. These aggregative multicellular species, such as the slime mold Dictyostelium, usually live as single-celled organisms. However, as their name suggests, the multicellular, slime-like form can move to a suitable habitat and grow a stalked fruiting body, which allows their spores to spread to nutrient-rich new locations.
The issue with this kind of multicellularity is that non-related individuals, or even those that don’t actively participate in cooperation (cheaters), can end up among the surviving cells. Since they don’t help, they can invest all their energy into feeding and reproduction—at the expense of the cooperative cells. This not only endangers the survival of the cooperative cells but ultimately the species itself, as too many cheaters would prevent the formation of the multicellular structure needed for reproduction. So, how can an aggregative multicellular species survive if cheaters always reproduce faster than cooperators? This is a particularly important question in the context of evolutionary transitions, where maintaining cooperation against cheaters is crucial.
Several hypotheses exist to explain why we see successful aggregative multicellular species nevertheless. One theory suggests that aggregation offers protection against predators: the more single cells stick together, the harder it is for a microbial predator to prey on them. Another hypothesis is that periodic starvation necessitates colonizing new habitats, which requires cooperative cells, thus even cheaters depend on them.
Researchers from the Institute of Evolution and ELTE University investigated these two hypotheses, examining the effects of aggregation and colonization under individual selection and group selection. They developed an individual-based, spatial computer model simulating the life cycle of a slime mold-like single-celled organism. In the model, cooperative cells produce the “glue” necessary for aggregation, while cheaters do not. The computer simulations clearly demonstrated that defense against predators is essential for the survival of cooperators in a continuously resource-rich environment. However, if resources periodically become scarce, predator-driven selection is not only insufficient but is also unnecessary for maintaining cooperation and multicellularity—it is a must to colonize new habitats.
Lifecycle of the slime mold Dictyostelium discoideum. (Source of insets: Wikimedia.) Single-celled slime molds usually start to aggregate when resources become scarce, and cells begin to starve. A secreted molecule (cAMP) coordinates movement to a tight aggregate that ultimately forms a slug. This motile form moves around to find a suitable spot for sporulation where it grows to a fruiting body with a stalk and spores in the head. Only the spores will survive to see the next habitat. The researchers have simplified this complex life cycle in their computer simulations, retaining only the crucial steps. Drawn by: István Zachar Photos: By Bruno in Columbus; by Usman Bashir (Copyright: CC BY-SA 4.0 Deed) and by Tyler Larsen (Copyright: CC BY-SA 4.0 Deed )
The researchers examined various colonization mechanisms (dispersal, fragmentation, aggregative spore formation, etc.) and found that only aggregative reproductive mechanisms can sustain cooperation long-term and robustly in such fluctuating environments. Thus, in a changing environment, group selection is more crucial than individual selection, in maintaining cooperation. The results suggest that these mechanisms played a key role in the evolutionary development of aggregative multicellularity.
In a nonchanging environment, predation, or any size-dependent selection, is enough to give a chance for cooperators to survive (top right). Without predation, however, cheaters will always win (top left). In a changing environment, when there is need to colonize new habitats, random dispersion decreases the chance of cooperators due to disrupting aggregations (middle). However, aggregation and aggregation-based colonization can effectively maintain cooperators against cheaters with or without predation (bottom left). Figure: István Zachar and István Oszoli
Dispersal is a crucial process in community ecology, through which individuals of a species can move into new and often different habitats. Species spread can happen actively, with individuals moving on their own, or passively, aided by dispersal agents. Understanding the dynamics and constraints of dispersal is a key to predict how species will adapt to changing environments, and can indirectly support biodiversity conservation and ecosystem stability.
The study of alien species dispersion is an important though relatively under-studied aspect of biological invasions. The colonisation of isolated wetlands and the introduction of pioneer and alien species are observable phenomena, but the underlying mechanisms are largely speculative. Researchers from the Institute of Aquatic Ecology at the HUN-REN Centre for Ecological Research have undertaken experiments on fish and plants to test hypotheses related to alien species dispersion. Previously, it was widely believed that waterbirds played an important role in the dispersal of fish in isolated water bodies, with fish eggs surviving passage through birds’ digestive tracts (i.e. endozoochory). Researchers at HUN-REN CER recently confirmed this hypothesis—the first such confirmation globally. However, questions persist regarding its prevalence among bony fishes and the variability in dispersal capacities across species.
In a series of feeding experiments with mallards, the researchers investigated the passive dispersal abilities of several common native (Wels Catfish, Common carp, Pike perch, Tench) and alien (Hybrid African catfish, Grass carp, Pumpkinseed, Amur sleeper, Stone moroko) fish species. In their paper, published in the journal Ecography, they reported the recovery of viable embryos of five fish taxa in the faeces of mallard, with successful hatching into larvae in one native (Tench) and one alien (Stone moroko) species. This result provide evidence that endozoochorous dispersal might be a widespread but likely rare phenomenon among bony fishes, with significant variability between species likely due to unique egg characteristics.
Herbivorous birds are known to play a significant role in seed dispersal, dietary studies from Europe showed that waterbirds can disperse hundreds of plant species, including many aliens. Moreover, passage through their digestive system can affect seeds’ germination rates. In a similar feeding experiment, researchers from HUN-REN CER compared the endozoochorous dispersal ability of six pairs of closely related (i.e. congeneric) alien and native wetland plant species. In their study, published in Freshwater Biology, they found that alien plant species can disperse more efficiently, with significantly higher seed passage rates.
However, these seeds germinated more slowly after gut passage compared to native species. Higher seed passage contributes to higher “propagule pressure” in new habitats, increasing the likelihood of establishing new populations of alien species. The delayed germination of aliens’ seeds also can offer a competitive edge to non-native species, particularly if they exhibit a fast growth rate and higher trait plasticity. Considering that mallards typically move several kilometres per day and even longer during migrations long-distance dispersal might be common and important for all studied plant species. Mallards also make shorter daily movements between wetlands, which might assist alien species to become fully established after their introduction to an area.
Pollinators are declining rapidly, largely due to land conversion and intensification of agriculture. To mitigate their crisis, low-disturbance habitats, such as sown wildflower plantings (commonly known forms are wildflower strips at the edges of arable fields), could promote pollinators by restoration of their resources (food, sheltering and nesting habitats). However, comprehensive knowledge is lacking on how landscape context, spatial configuration and age of wildflower plantings, seasonality and flower composition affect pollinator communities, especially from East-Central Europe.
To understand these effects, researchers from the HUN-REN Centre for Ecological Research established diverse native wildflower plantings within heterogeneous and homogeneous agricultural landscapes, by two spatial configurations: one large field or three smaller strips. Floral resources and wild pollinator insects (wild bees, hoverflies, butterflies) were sampled, in early and mid-summer, for two years after establishment (2020-21).
Flower resources of the sown plant species increased continuously, and were complemented at high rate by flowering plant species from the soil seed bank, especially in the first year. Both flower abundance and diversity increased the abundance of pollinators, highlighting the important role of using diverse seed mixtures. Wild bee abundance and species richness increased year by year and season by season, while butterfly abundance also demonstrated a yearly increase after establishment. Hoverfly abundance and species richness, however, showed an opposite trend, possibly due to the inter-annual variation. Wild bee and butterfly abundance was higher in the heterogeneous than in the homogeneous landscapes. Researchers did not observe any significant local effects of spatial configuration itself on pollinator populations.
Field-work photos from the transect walk method and the flower resources assessment from the four years of the study Photos: Borbála Bihaly (top left, buttom right) and Áron Bihaly (buttom left, middle and top right)
Our results emphasize that to support pollinators effectively, future wildflower plantings should be maintained for multiple years, in order to maximize floral diversity and ensure continuously available flower resources throughout the entire season.
Further results from the upcoming years and similar long-term and landscape-scale experimental studies are needed to understand all the benefits and ecological processes of diverse native wildflower plantings especially in understudied European regions.
The diverse floral resource of wildflower plantings in the second and third years and the pollinator insects visiting the flowers Photos: Viktor Szigeti (top left and middle left) and Borbála Bihaly (bottom row, top right and middle right)
