Urbanization is rapidly transforming natural habitats and poses growing challenges for wildlife. One lesser-known consequence is its potential impact on bird song, which plays a crucial role in communication, reproduction, and survival. In a new study examining 65 European songbird species, researchers found that birds living in more urbanized environments tended to use a wider range of dominant frequencies in their songs. However, clear changes in dominant song frequency were detected only in some species. These findings suggest that urbanization does not universally alter bird song, but both changes and the absence of adaptation may still have important consequences for birds living in noisy cities. The researchers emphasize the need for further studies and for urban planning measures that help maintain suitable habitats for diverse bird communities.
The study explored how urbanization influences bird vocalizations across and within species, an area that remains relatively understudied despite its importance for bird fitness and population health. As cities continue to expand, understanding how wildlife responds to urban environments becomes increasingly important. Using a phylogenetic comparative approach, the researchers analyzed vocal differences linked to urbanization in 65 European passerine species. The xeno-canto database was used to obtain vocalizations from these species throughout Europe. The researchers also examined whether factors such as social behavior, migration patterns, vocal complexity, and the species’ frequency of occurrence in cities were related to these vocal changes.
The results showed that species living in more urbanized habitats generally exhibited a broader dominant frequency range in their songs. This may suggest that birds living in cities are able to widen their frequency range and so avoid masking from different noise sources. However, urbanization-related shifts in dominant frequency itself appeared only in certain species (e.g. the robin, the European serin and the hooded crow), rather than representing a universal pattern. Unexpectedly, species for which song change in cities was previously found, such as the great tit or the European blackbird, did not alter their songs along an urbanization gradient according to the present study. This negative result highlights the need for studying the effect of urbanization on bigger spatial scales and across species. In addition, none of the investigated species traits explained the observed differences in song characteristics, and a species’ occurrence in urban areas was not associated with its vocal traits or song flexibility.
– Overall, the findings suggest that urbanization does not impose a single, general effect on bird song frequency and that vocalization differences alone are unlikely to determine whether a species can successfully inhabit cities – says Mónika Jablonszky, one of the authors. Nevertheless, the researchers caution that both song adaptation and the lack of adaptation in noisy urban environments may affect birds at both the individual and population levels. They therefore highlight the importance of continued research and conservation efforts aimed at preserving and creating bird-friendly habitats in urbanized areas.
Research:
Mónika Jablonszky, László Zsolt Garamszegi; Urbanization-related vocal variation in passerines: a comparative study. Proc Biol Sci 1 May 2026; 293 (2071): 20260487. https://doi.org/10.1098/rspb.2026.0487
Citizen science projects are playing an increasingly important role in ecological and conservation research worldwide. In these programs, members of the public support researchers by submitting photographs, audio recordings, observations, or even by contributing to data analysis. In Hungary, no fewer than 17 such initiatives combined their datasets in a joint study.
The authors aimed to understand which socio-economic and environmental factors influence participation patterns in Hungary. By comparing the spatial distribution of citizen science data with an independent administrative dataset (municipality level data on income, education, demography, density and protected areas), the researchers identified several general trends as well as numerous project-specific relationships.
For example, they found more per capita observations from municipalities with higher proportions of protected natural areas and lower population densities. Furthermore, excluding Budapest, the capital, both the proportion of people with diplomas and the proportion of elderly people showed a positive correlation with participation activity. In contrast, no consistent general pattern emerged regarding wealth or the proportion of children, although several project-specific relationships were observed.
The study not only reveals how citizen science data are distributed across Hungary, but also provides robust support for the view that various biases must be taken into account when analyzing such data. The authors hope that their findings will help researchers in other countries design more effective projects and produce more accurate analyses by accounting for some of these or similar biases.
In recent years, citizen science methodology has gained significant momentum and is becoming increasingly important in large-scale ecological and conservation research. By involving volunteers, it enables a level of spatial and temporal coverage that would often be unattainable within traditional research frameworks. However, the method also comes with specific challenges. One of the main criticisms of citizen science data is that observation density can vary substantially across space and time, making direct comparisons with systematically collected datasets difficult. These patterns may partly reflect real biological differences, for example, in the case of species that occur seasonally or in patches, but they are also strongly influenced by the distribution and behaviour of volunteers.
To address this issue, a research team led by the HUN-REN Centre for Ecological Research applied a novel approach. They compared a database of more than 300,000 citizen science observations with regional data from the Hungarian Central Statistical Office (HCSO) at the municipality level. The citizen science data included projects focusing on arthropods, molluscs, reptiles, birds, mammals, but also on streams and ponds. In simple terms, they examined whether the characteristics of local populations and environments systematically influence the number of submitted observations. One of the key strengths of this approach is that it combines two independent data sources: citizen science data reflect volunteer activity, while HCSO data describe socio-economic and environmental background variables. This independence helps to avoid biases commonly associated with survey-based studies. The applied meta-analysis allowed the identification of both project-specific and general patterns, making the results applicable at multiple levels.
The analysis shows that participation is not random. A positive relationship was found between participation and the proportion of protected areas: in general, municipalities with higher proportions of protected areas receive more observations. Population density shows a more complex pattern: in general analyses, it was negatively associated with participation, but when Budapest was excluded (due to its exceptionally high density and other unique characteristics) the effect disappeared. In this adjusted analysis, the proportion of people with a diploma and the proportion of elderly residents both showed positive correlations with participation.
The study also identified finer-scale patterns. For example, citizen science projects that involve observations in private gardens showed a significant positive relationship with the proportion of children, a pattern not observed in other types of projects. Another interesting finding was that projects focusing on specific habitats tended to receive more observations from municipalities with lower levels of education and income, which may be linked to lower levels of urbanization. At the same time, it is important to interpret these results within their specific context. Participation patterns are influenced by many factors, including the research topic, the effectiveness of communication, and the institutional and social background of each project.
Overall, as the leading author Zsóka Vásárhelyi argues: “the majority of citizen science data are very likely biased”; however, they remain extremely valuable, as long as researchers consciously account for their biases during project design, data collection, analysis, and interpretation.
Publication: Zsóka Vásárhelyi, Barbara Barta, Marianna Biró, Zoltán Csabai, Gábor Földvári, Bálint Halpern, Zsófia Horváth, Erika Juhász, Balázs Károlyi, Kornélia Kurucz, Zsuzsanna Márton, László Mezőfi, Péter Lovászi, Barna Páll-Gergely, Bálint Pernecker, Ádám Selmeczi-Kovács, Zoltán Soltész, Éva Szabó, Ágnes Turóci, Vadonleső Group, Judit Vörös, László Zsolt Garamszegi : Environmental and socio-economic factors behind data provision in 17 citizen science projects
As climate change intensifies, one of the key challenges facing forestry is how to balance efficient timber production with the preservation of forests’ climate-regulating functions, biodiversity and resilience. The growing public demand for recreation in forests, together with increasing opposition to clear-cutting, is also driving the search for more sustainable management approaches.
A recently spreading forest management system, the so called continuous-cover forestry may provide a viable alternative to conventional rotation forestry systems. By mimicking natural forest dynamics, this approach creates only small-scale disturbances in the canopy through selective thinning or the opening of gaps measuring a few hundred square meters. As a result, the forest habitat remains continuously intact, helping preserve the cool, humid microclimate and the associated forest biodiversity.
In oak-dominated forests, however, management based on fine-scale interventions raises several practical questions. Oaks are light-demanding tree species: they regenerate poorly under a closed canopy, yet in overly large canopy openings they may be rapidly outcompeted by faster-growing woody and herbaceous species that suppress young oak seedlings. Therefore, a new study by researchers from the Forest Ecology Research Group at the HUN-REN Centre for Ecological Research investigated which canopy gap sizes and shapes most effectively support natural oak regeneration while maintaining continuous forest cover.
“Foresters have relied on conventional rotation forestry systems for decades, so transitioning to a fundamentally different management philosophy is not easy,” says Flóra Tinya, research fellow at the Forest Ecology Research Group and first author of the study. “To encourage the wider adoption of ecologically gentler forestry practices, we need to provide scientifically grounded knowledge that can help practitioners develop and refine new management techniques.”
The research was conducted in collaboration with forestry professionals from Pilis Park Forestry Company. Péter Csépányi, Deputy CEO responsible for forestry and nature conservation at the company, has accumulated decades of practical experience in regenerating oak stands under continuous forest cover. “This collaboration allowed us to align the research questions closely with the practical challenges encountered in forest management,” Tinya adds.
The study formed part of the Pilis Gap Experiment, conducted in a sessile oak–hornbeam forest in the Pilis Mountains of Hungary. Researchers examined the effects of two different gap sizes and two different gap shapes — circular and elongated. Previous studies by the team had already demonstrated that gap size and shape strongly influence microclimatic conditions and the development of understory vegetation. In the newly published work, the researchers analyzed how sessile oak (Quercus petraea) saplings responded to the resulting light and soil-moisture conditions, and how competition from other plant species affected their development.
In large, circular gaps, oak saplings develop rapidly, but they face strong competition from hornbeam and other fast-growing species.
The researchers found that oak regeneration could be initiated in all investigated gap types, but sapling performance and the amount of required tending effort differed considerably among them.
Initially, the most favorable light and soil-moisture conditions occurred in large circular gaps, where tended oak saplings — those released from competing vegetation — showed the fastest growth. However, these improved environmental conditions also favored competing species. Hornbeam (Carpinus betulus), dogwood (Cornus sanguinea) and bramble (Rubus fruticosus agg.) expanded vigorously in these gaps and increasingly suppressed the developing oak saplings over time. Within a few years, the dense vegetation substantially reduced the initial surplus of light and moisture in the gaps. As a consequence, successful oak regeneration in circular gaps required intensive control of competing vegetation.
The researchers found that elongated canopy gaps may provide a better compromise between suitable environmental conditions for oak seedlings and the amount of maintenance work required. Light availability in elongated gaps was similar to that of circular gaps with the same area, but the increase in soil moisture was more moderate, limiting the spread of competitive species.
Elongated gaps provide suitable light conditions for oak regeneration, while the moderate surplus in soil moisture limits the spread of competing species. The researchers also monitored a wide range of biodiversity and environmental variables in the studied gaps, including air temperature and humidity.
“Gap size also matters,” says Tinya. “Among the elongated gaps, the smaller ones had lower competition because of the more moderate light conditions, meaning they required the least maintenance.” Although oak seedlings also grew more slowly in the small, elongated gaps, the researchers argue that this slower initial growth is of limited practical importance given the long lifespan of oak trees. “When these trees are typically harvested only after more than a hundred years, somewhat slower growth during the first few years is not particularly significant,” Tinya explains.
At the same time, the study also showed that after several years the small, elongated gaps no longer fully satisfied the increasing light demand of the growing oaks. According to the researchers, the gaps may therefore need to be enlarged after five to six years. They hypothesize that by then the saplings will already be sufficiently established to compete more successfully with other species — a prediction they plan to test in future research.
Small, elongated gaps may offer an additional advantage as well: acorns from surrounding mature oak trees can more easily reach the center of these gaps, enabling the establishment of new seedlings over multiple years.
The findings demonstrate that with appropriately designed canopy gaps, oak forest regeneration can be achieved while continuously maintaining forest cover. The researchers provide detailed recommendations to support successful implementation, contributing to the broader adoption of forestry practices that help preserve forest microclimates and biodiversity while also enhancing forests’ resilience to climate change.
At the same time, the authors emphasize that the long-term goal is unlikely to be the maintenance of nearly pure oak stands typical of conventional rotation forestry systems. Instead, they argue that more diverse mixed-species forests may ultimately provide greater ecological and economic stability.
Margaret Gathoni Gitau, one of the co-authors, takes notes during fieldwork. Numerous aspects of oak regeneration were assessed, including not only the survival and height growth of oak saplings released from competition — reflecting the environmental conditions created by different types of canopy openings — but also the abundance of naturally regenerating oak seedlings under competitive conditions.
Research:
Tinya, F., Csépányi, P., Gitau, M. G., Horváth, Cs. V., Kovács, B., Németh, Cs., Ódor, P. (2026): Elongated gaps provide a good compromise between abiotic and
competitive conditions for sessile oak regeneration. Forest Ecosystems, 16: 100472. https://doi.org/10.1016/j.fecs.2026.100472
Main photo: Hemispherical canopy photograph of a large, elongated gap. Researchers use such images to calculate the amount of incident light reaching the forest floor.
A new study published in the journal People and Nature reveals a significant gap in public awareness regarding one of the world’s most widespread invasive species: the freshwater jellyfish Craspedacusta sowerbii. Despite being present on six continents and well-documented by scientists in Europe, this unnoticed (cryptic meaning “under the radar”) invader remains largely unknown to the public, a factor that researchers say may be hindering the development of early warning systems and effective environmental policy.
Likely native to the Yangtze River basin in China, C. sowerbii was first described outside its native range in 1880 in a London ornamental pond. Since then, it has spread globally, potentially through the transport of its tiny, resilient polyp and podocyst life stages, attached to aquatic plants, birds, or submerged substrates. In Europe, its presence is now established in regions ranging from Spain and Italy to Finland and Russia.
To assess how the public perceives this invasion, an international team of researchers conducted a 22-month multilingual survey across 17 European countries, collecting 1388 responses. The results highlight a profound lack of recognition: over 80% of respondents did not know the species’ scientific name, and only 10% could correctly identify it as C. sowerbii.
Perhaps most striking was the ecological confusion among respondents. Nearly half of them (49%) claimed to have observed it in the sea, even though C. sowerbii is strictly a freshwater species. Researchers suggest this “taxonomic confusion” stems from a bias toward marine jellyfish frequently portrayed in the media. This lack of awareness classifies the invader as “cryptic”, progressing silently by a life cycle hard to observe, or its appearance remaining sporadic.
When people do encounter these jellyfish, their reactions are a mix of fascination and caution. Respondents generally used positive terms to describe the animal, calling it “beautiful” (21%), “sublime” (18%), and “delicate” (18%). However, encountering mass occurrences of the species, which can happen suddenly during warm summer months, triggered feelings of nervousness and caution in over 50% of participants.
Regarding safety, the study provides some reassurance. While 8% of respondents reported being stung, over half (56%) of those individuals reported no pain at all, and severe pain was extremely rare. Overall, the species is perceived as an aesthetic curiosity rather than a direct physical threat.
The study utilised a Bayesian Network analysis to determine what factors most influence public concern and support for management. Interestingly, demographic factors like age or gender and even formal scientific knowledge played only a secondary role. Instead, direct personal observation was the strongest predictor of whether an individual felt the species warranted public discussion or governmental action.
“These results confirm that, in the case of a little-publicized species, personal experience overrules scientific information in shaping public opinion”, the authors state. This suggests that management strategies should focus on visual and sensory pedagogy, leveraging field experiences and citizen science, rather than just distributing dry biological data.
The authors argue that the focus of current invasive alien species (IAS) frameworks on “charismatic” or economically damaging invaders leads us to underestimate silent dynamics that could be restructuring our ecosystems. While the exact ecological impact of C. sowerbii is still being studied, it is known to compete with fish larvae for food. Furthermore, climate change is expected to accelerate its spread, as rising water temperature may facilitate the transition from the microscopic polyp to the visible medusa stage.
The study urges management authorities and NGOs to integrate “invisible” invasive species into their action plans. By empowering citizens to report sightings through citizen science platforms, researchers can fill critical data gaps and create a more inclusive, responsive monitoring system for the subtle ecological signals of global change.
Research: Guillaume Marchessaux, Kristína Slovák Švolíková, Barbora Števove, Ali Serhan Tarkan, Daniela Giannetto, Cristina Preda, Belma Kalamujić Stroil, Maciej K. Mańko, András Abonyi, Álmos Becz, Massimo Morpurgo, Evgeny A. Pakhomov, Levan Mumladze, Mar Bosch-Belmar, Aino Hosia, Patricia Ventura, Jamileh Javidpour, Florian Lüskow : When invasions go unnoticed: Public perception of the freshwater jellyfish Craspedacusta sowerbii in Europe
Not only the salinity of water, but also the composition of dissolved ions plays a key role in shaping the structure of bacterial communities living in lakes. These aquatic bacteria are essential for nutrient cycling and also strongly influence water quality. According to a study led by the Microbial Ecology Research Group of the Institute of Aquatic Ecology at the HUN-REN Centre for Ecological Research, the composition of ions has a much stronger effect on bacterial community structure than the amount of dissolved salt alone.
The researchers analyzed 375 water samples collected from 130 lakes worldwide, ranging from freshwater to hypersaline environments, including both soda lakes and saline lakes. In soda lakes, sodium, carbonate and bicarbonate ions are dominant, while the ionic composition of saline lakes resembles that of seawater, where chloride ions are dominant with sodium. There are several soda lakes and pans in Hungary, especially in the Kiskunság region, and both Lake Fertő and Lake Velence are also classified as soda lakes, although their total salt content is relatively low. In contrast, Lacul Ursu in Sovata, Transylvania (Romania), belongs to the other type, containing extremely high concentrations of dissolved salts.
The aim of the study was to investigate how the dominant dissolved ions in lake water – especially differences between carbonate- and chloride-rich waters – influence the structure of aquatic bacterial communities. The results clearly showed that the composition of planktonic bacteria is more strongly influenced by the type of dissolved ions than by total salinity itself. Several bacterial groups were found to be strongly associated with specific water types. For example, certain groups of Actinobacteria preferentially occur in soda lakes. The study also revealed that these specialized bacterial groups are evolutionarily related, suggesting that habitats with different ionic compositions also have shaped the evolution of microorganisms over long periods of time.
These findings contribute to a better understanding of lake ecology, particularly because microscopic organisms that influence food webs and water quality respond very rapidly to climate change and other human-induced environmental changes.
The study was published in the prestigious scientific journal Limnology and Oceanography Letters under the title “A matter of salt: Global assessment of the effect of salt ionic composition as a driver of aquatic bacterial diversity”.
Publication:
Szabó A, Székely AJ, Boros E, Márton Zs, Csitári B, Barteneva N, Anda D, Dobosy P, Eiler A, Bertilsson S, Felföldi T. 2026. A matter of salt: Global assessment of the effect of salt ionic composition as a driver of aquatic bacterial diversity. Limnology and Oceanography Letters 11: e70088.
Selection in the breeder scenario on traits unlinked or linked to controllability. Animal (and plant) breeding has selected for traits that do not affect the ability of humans to control the reproduction of the affected organisms; thus, control is maintained (Top). In contrast, eAI will likely be selected for increasing cognitive capacity (denoted by “benchmark” indicators in the figure), which may erode control and weaken the alignment (Bottom).
Evolutionary biology holds clues for the future of AI, argue researchers from the HUN-REN Centre for Ecological Research, Eötvös Loránd University, and the Royal Flemish Academy of Belgium for Science and the Arts. In a new Perspective published April the 20th in PNAS (the flagship science journal of the National Academy of Sciences of the USA), the team warn that evolvable AI (eAI) systems that can undergo Darwinian evolution may soon emerge, and they will generate special risks that can be understood, and mitigated, based on insights from evolutionary biology.
“The power of evolution is manifest in the history of biological evolution on Earth, which has created the cognitive capabilities of the human mind,” said Eörs Szathmáry, professor of evolutionary biology at the HUN-REN Centre for Ecological Research and at Eötvös Loránd University, Budapest, and Director of the Parmenides Center for the Conceptional Foundations of Science in Pöcking, lead author of the study. “We find it inevitable that the development of AI systems will eventually, and probably soon, tap into that power,” added Luc Steels, emeritus professor of AI at the University of Brussels (VUB) and member of the Royal Flemish Academy of Belgium for Science and the Arts, co-corresponding author of the paper.
The study outlines the use of evolutionary concepts and components in current AI research and explains how further developments, particularly agentic AI, may soon give rise to AI systems that fulfill all criteria for genuine Darwinian evolution. Such systems may open a new epoch in AI development, passing hurdles that even current learning AI systems cannot easily negotiate. However, “lessons from biological evolution teach us that evolving AI systems will be particularly hard to control,” said Viktor Müller, associate professor at Eötvös Loránd University and first author of the study. The two evolutionary biologists, Szathmáry and Müller teamed up with robotics and AI expert Steels to give an advance warning on the risks of eAI—and to recommend possible measures to mitigate them.
Using illustrative examples from biological and artificial (in silico) evolution, the study underlines the propensity of evolution to produce ‘selfish’ actors which, in the case of eAI, increases the risk of breaking the ‘alignment’ with human goals. Importantly, while much of the current discussion on AI risks centers on ‘Artificial General Intelligence’ (AGI), a theoretical threshold where AI matches or surpasses human intelligence across all cognitive tasks, lessons from evolution show that superior intelligence is not a pre-requisite for the ability of an organism to harm or manipulate another; for example, the simple rabies virus has evolved to manipulate and exploit its mammalian hosts. Evolvable AI may break the alignment and pose risks well before AGI is reached, and the risk does not require any further special circumstance to arise: AI systems and humanity share common resources, so an efficiently self-replicating system will sooner or later divert resources that are vital to our survival.
The study warns that any attempt to control reproduction will, unless control is perfect, select most strongly for traits that enable escape from that control. Analogies from biology involve bacteria and pests rapidly evolving resistance to antibiotics and pesticides. On the top of this general rule of evolution, the central drive in the development of AI systems, to achieve improved cognitive ability, further exacerbates the risk: while thousands of years of animal breeding has made domesticated species more, rather than less, controllable, selection for increasing ‘intelligence’ will increase the ability and probability of AI systems to deceive humans and to escape control.
Finally, while evolution by natural selection is hard enough to control, the study enumerates multiple ways in which the evolution of AI systems can beat the speed and efficiency of biological evolution. In contrast to biological organisms, eAI will be able to inherit ‘acquired’ traits and even improve its function by design rather than having to wait for random mutations to generate useful variations. “The potential speed of AI evolution is deeply alarming,” said Steels.
The authors recommend guardrails that may mitigate the risks associated with eAI. Above all, the ‘reproduction’ of AI systems must remain under centralized human control which needs to be absolute and complete.
“We hope our warning arrives in time, and regulations can be put in place before eAI would really take off,” said Müller. “If we fail to act, we may witness a new ‘major transition’ in evolution, in which eAI will replace or at least dominate humans. Our future may be at stake,” warned Szathmáry.
This research was supported by funding from the European Research Council, the National Research, Development and Innovation Office in Hungary, and the European Innovation Council. The final version of the paper took shape during collaborative writing sessions at the Parmenides Foundation (Pöcking).
About:
Szathmáry, Eörs is an evolutionary biologist, a member of the Hungarian Academy of Sciences, and the chairman of the Sustainable Development Committee of the Hungarian Academy of Sciences. In his research, he studied and modeled many evolutionary processes from the origin of life to the development of human language skills. His book, The Major Transitons in Evolution, co-authored with John Maynard Smith, is considered a cornerstone of modern evolutionary biology.
In connection with the objective set out in the government program —
“We will restore the autonomy of science. We will prepare a new, transparent law that reinstates the professional independence of the MTA (Hungarian Academy of Sciences) and the research institutes, and settles the status of academic assets.”
— we propose reconsidering the future vision and operating principles of the organization established by the HUN-REN law.
The HUN-REN research network was established as an organization independent of the central budget, but the principle of researchers’ self-governance is only marginally reflected in the legislation that created the network. It is worth considering whether the size and centralizing ambitions of the newly established administrative governing center are in line with the research and innovation potential represented and to be developed by the network.
The Public Task Financing Contract (KFSZ) provides funding for six years, aiming to improve scientific performance, innovation, internationalization, and the training of the next generation of researchers. The performance evaluation indicators, priorities, and target values of the KFSZ require reconsideration and clarification.
We consider it of fundamental importance to resolve the unconstitutional situation regarding the real estate assets owned by the Hungarian Academy of Sciences MTA and used by the institutions of the research network.
The directors of the HUN-REN research institutions agree that from the decisions of the new government we expect a strengthening of the self-governing nature of scientific autonomy, as well as the creation of a supportive science policy environment in which decisions about the development of research institutions can be made jointly by representatives of the scientific community and the institutions themselves.
We propose the following measures and agree with the general directions implied by these decisions:
1) The government should amend the HUN-REN law. The most important element of the amendments should be to ensure researchers’ self-governance and the scientific, economic, and operational autonomy of research institutions. We propose that the founding rights of HUN-REN be transferred by law to the MTA, and that the source of the annual funding specified in the KFSZ be moved under the Academy’s budget chapter. The legal status of the institutions should not change; their position outside the scope of the public finance law should be maintained.
2) With the involvement of the MTA, it should be examined how the legal deadlock regarding property rights between the MTA and HUN-REN can be resolved as soon as possible through amendments to the KFI, MTA, and HUN-REN laws.
3) The government and HUN-REN should, by mutual agreement and in a forward-looking and realistic manner, revise the indicators and target values of the KFSZ while keeping the funding specified in the contract unchanged.
If the research network continues to operate within the framework of the MTA, we propose preserving the integrity, organizational independence, and operational autonomy of the institutions, thereby ensuring their independence from public body and governance structures. As leaders of HUN-REN institutions, we stand ready to participate in working out the details.
Zsolt Dombrádi HUN-REN Institute for Nuclear Research
Tibor Magyar
HUN-REN Veterinary Medical Research
Gábor Vasas
HUN-REN Balaton Limnological Research Institute
László Kiss
HUN-REN Research Centre for Astronomy and Earth Sciences
Ákos Horváth
HUN-REN Centre for Energy Research
István János Kovács
HUN-REN Institute of Earth Physics and Space Science
Beáta Sperlágh
HUN-REN Institute of Experimental Medicine
László Zsolt Garamszegi
HUN-REN Centre for Ecological Research
András Stipsicz
HUN-REN Alfréd Rényi Institute of Mathematics
László István Monostori
HUN-REN Institute for Computer Science and Control
Ferenc Nagy
HUN-REN Biological Research Centre
László Buday
HUN-REN Research Centre for Natural Sciences
Péter József Lévai
HUN-REN Wigner Research Centre for Physics
This paper elaborates on the issues of microbial endosymbiosis stemming from conflict of interest and how multilevel selection can solve it once central control is gained by the host – given it has a nucleus. This is usually the case for extant endosymbiont of unicells (protists), where a huge asymmetry already exists (host being larger, with heterotrophic metabolism, assumed to be phagotrophic, having a nucleus, control mechanisms, etc.). However, among prokaryotes, this is not the case, as prokaryotic partners are far from being as different size- and structure-wise. Presumably there is something preventing prokaryotes to form endosymbiotic partnerships more often. The issue pertains especially to mitochondrial origins. Since we do not know if the ancestral host to mitochondria was nucleated or not, we cannot exclude the possibility that their success was not only due to the metabolic and architectural synergy the mitochondrial ancestor may have provided for the host but due to the fact that the host already could 1) shield its genome from uncontrolled hybridization with the symbiont’s genes plus 2) had the means to unilaterally exert control on the symbiont.
Our paper discusses why endosymbiosis (one microbe living inside another) is common in complex cells but rare in simple prokaryotes. In modern single-celled eukaryotes, the genetic interaction between host and symbiont is more asymmetric, potentially due to the nuclear envelope, acting as a barrier. In contrast, prokaryotes lack such features and are more equal, making stable partnerships harder. For mitochondria, it’s unclear if the original host had a nucleus, but if it did, that may have helped it control the symbiont and avoid harmful genetic interference – making the partnership more successful.
The amount of expected horizontal gene transfer (HGT) under various conditions of symbiosis. Red arrows indicate potential gene transfer, green arrows blocked transfer attempts; the strength of arrows indicates presumed magnitude of successful transfers in unit time.Overview of theories proposing various orders of events including the origin of nucleus, mitochondria and intronal evolution. A) mitochondria-early scenario of (Martin and Koonin 2006): An archaeon (without NE) acquires the mitochondrial endosymbiont as the first step. The endosymbiont incurs an increased level of HGT (EGT; thicker arrow) and as a result, Group II introns (among other genes) make their way into and proliferate in the host genome. Introns that lose their self-splicing ability become a burden for the host, and as a result, NE and spliceosomal machinery evolve only after intron proliferation. B) Early intron evolution and late mitochondrial acquisition based on (Vosseberg et al. 2020, 2022). Group II introns were either acquired by HGT by the host from pre-mitochondrial endosymbionts or were vertically inherited from archaeal introns already present in the lineage. A rudimentary version of NE is formed (or other mechanism to separate transcription and translation) with a wave of gene duplications potentially introducing further introns. As introns proliferated throughout the genome, the spliceosome evolved for the same reasons as described above. As the mitochondrial endosymbiont was established, a second wave of gene duplications and possibly more introns further shaped the proto-eukaryotic genome. C) Proposed hypothesis assuming serial endosymbiosis before mitochondria (Pittis and Gabaldón 2016, Gabaldón 2018), compatible with scenario B. An increased level of HGT from transient endosymbiotic partners perturb the host genome before the NE fully evolved. Early endosymbionts could not stabilize due to the lack of a NE that would enable controlled EGT and, ultimately, central control over the symbionts. The rest of this scenario follows B.
Solitary wild bees and wasps play a key role in ecosystem functioning – both as pollinators and as biological pest control agents. Yet we still know surprisingly little about the life history, population dynamics and ecological interactions of many species. Researchers at the HUN-REN Centre for Ecological Research have recently published a study presenting the first detailed, step-by-step protocol for using trap nests to study cavity-nesting Hymenoptera, i.e., solitary bees and wasps (Fig. 1). Standardising this sampling method will allow data collected in different parts of the world to become comparable, which is an important step towards improving pollinator conservation.
Fig. 1
The trap nests used by researchers may look familiar to many people: “bee hotels”, increasingly common in gardens, consist of hollow stems or wooden blocks with drilled holes (Fig. 2 – Main foto). These structures mimic natural nesting sites and attract cavity-nesting bees and wasps. Inside the cavities, brood cells are constructed where bee and wasp larvae develop on the food provisions stored by the mother (Fig. 3). The special advantage of this method is that it allows researchers not only to identify the species present but also to study a range of ecological processes – including nesting behaviour, the presence of parasites, and the use of environmental resources such as food and nesting materials.
Fig. 3
The newly published study provides detailed guidance on how to construct trap nests, when and how to place them in the field, and how to collect and process the samples found within them. The entire process can take up to nearly two years – from deploying the nests, through larval development and overwintering, to the final identification of species (Fig. 4).
Fig. 4
“Trap nests contain a remarkable amount of ecological information. From a single nest we can learn what food the nesting individuals collected, what materials it used to build the nest, and which natural enemies harnessed the offspring,” said Áron Bihaly, the first author of the study. “The aim of the protocol is to ensure that researchers around the world collect these data using the same methods, making the results of different studies comparable.” He added that “although the data collection process can be lengthy, it allows us to obtain detailed information that is almost impossible to collect with any other sampling method.”
One advantage of the method is that it can provide valuable data with relatively little fieldwork. The nests are placed in the field in spring and collected in autumn, meaning that the samples provide insights into ecological processes throughout an entire season. The analysis of nests reveals not only which species are present, but also information about the structure of local insect communities, their reproductive success and how they use resources available in the surrounding landscape.
The researchers emphasise that standardised methods are particularly important in the context of the global pollinator crisis. Wild bees and other hymenopteran insects provide many ecosystem services, including pollination and the natural control of pest species. Monitoring changes in their populations is therefore essential for designing effective conservation measures. Trap-nest sampling has proven to be a particularly useful tool in this effort.
One of the online supplementary materials of the publication provides a detailed, illustrated guide to the bee and wasp species that nest in cavities in Hungary. This guide can also be useful for members of the public who maintain bee hotels. “Such protocols are not only useful for mainstream research, but they also open the door to involving wider communities in observations,” said Edina Török, one of the lead authors of the study. “For example, we are launching a survey of wild bees in Budapest with the involvement of local residents as part of the citizen-science UrbanBEE project. Within the project, we distributed bee hotels to participants, who record a few basic observations. Initiatives like this help us better understand how pollinators live in urban environments.”
The researchers hope that the new protocol will contribute to the wider and more consistent use of trap nests, which in the long term may support the conservation of pollinators and other insects, strengthen international ecological research collaborations, and help design more precise agri-environmental measures and habitat restoration efforts.
Related publication:
Bihaly Áron Domonkos et al. (2026): A standardised protocol for sampling cavity-nesting Hymenoptera using trap nests. Journal of Hymenoptera Research. https://doi.org/10.3897/jhr.99.183051
AI algorithms are increasingly developed to monitor vector populations based on either photos or sounds. However, the real-life accuracy of the models is highly dependent on the training data. Unfortunately, training data is still limited, both in matter of the species that are actually included, and the natural variation represented within a given species. In this study, researchers from HUN-REN Centre for Ecological Research, ELTE University, Budapest and University of Szeged show that mosquito sound is fairly consistent among species., especially if environmental parameters such as temperature are taken into account. This means that, to develop field-accurate AI identification models based on mosquito sounds, we either need to properly represent the natural variations caused by environmental and biological factors into the training data (especially temperature), or adjust the identification algorithm based on those factors. These types of models could help us monitor vector populations and implement efficient public health strategies.
Mosquitoes transmit several pathogens of public health importance, including malaria, dengue, chikungunya and ZIKA. These vector-borne diseases are responsible for millions of cases every year, and hundreds of thousands of deaths. The most effective way to cope with the threat of emerging or re-emerging vector borne diseases is the prevention by rigorous surveillance system, which can help early detection of risk and the initiation of mitigation efforts (e.g. mosquito control). In recent years, numerous technologies have been developed to monitor and control vectors and vector-borne diseases, many of which rely on the use of deep-learning, specifically for the detection and classification of species. Acoustic data in particular, used as passive acoustic monitoring, could allow the surveillance of vector populations in real-time, and assist timely public health decisions. Mosquitoes emit sound when they flap their wings during flight; the faster they beat their wings, the higher the sound. Mosquito sound varies based on several factors, including species, which is extremely useful because we only need to monitor a few species of interest; often those that transmit the diseases, but it could also apply to invasive species. AI-based algorithms already exist for the identification of mosquito species based on sound, and some perform rather well (up to 97%). However, there are a few caveats: (1) accuracies tend to decrease when many species are included, (2) few species are available in the training datasets, (3) the sounds of wild mosquito populations are likely much more variable than those represented in the training data, due to the impact of environmental (e.g. temperature, humidity) and biological factors (sex, age, size) on mosquito sound. All these aspects reduce the field applicability of AI-based species recognition based on mosquito sound. A study of researchers from HUN-REN Centre for Ecological Research, ELTE University, Budapest and University of Szeged investigates the last point, i.e. the impact of several environmental and biological factors on the variability of mosquito sound between species and between individuals.
The researchers captured and recorded hundreds of mosquitoes in Hungary, and used the recordings from the 10 most abundant species to evaluate how much mosquito sound varies among species and individuals. In addition, they assessed the impact of several factors on sound variability : temperature, humidity, time of day, sex, age and size (represented by wing length). Sound was fairly consistent among species and among individuals. However, the acoustic signal related to a given species was even more consistent when environmental and biological variables were controlled for.
Sex and temperature both affected significantly mosquito sound. Females had a lower sound compared to males; this is not surprising, as females are usually bigger compared to the males in most mosquito species. Temperature also affected mosquito sounds; usually a higher temperature resulted in a higher sound. Higher temperature increases insect metabolism (up to a point); thus mosquito muscles move faster when temperature is higher, and they can beat their wings faster. However, the importance of this increase varied between species, meaning that different species responded differently to temperature. This could be explained by the origin of the species (temperate vs subtropical), or their preferred host and the associated blood temperature (bird blood’s temperature is usually lower compared to mammal’s blood). This species-specific difference in response to temperature suggests that we cannot apply a simple temperature correction rule for mosquito sounds, or at least that we cannot apply the same mathematical formula to all species.
4-channel microphone used for the recording of mosquitoes. 4 small microphones are plugged into the Handheld Digital Recorder, and placed on the side of the mosquito cage. Even though recordings were done in a soundproof box, mosquito’s sound is really faint, so having a microphone on each side of the cage increases the chances of picking up its sound when it flies close to the microphone. Credit:Augustin Julie
“Our data demonstrates that we cannot ignore intra-specific and intra-individual variability for AI based acoustic classification. One solution for better integration of natural variance would be to adequately represent that environmental and biological variability in the training data. Unfortunately, such complete databases remain rare, especially for invertebrates, and building these extensive databases require a lot of time and effort” – said Julie Augustin, the first author of the publication. Alternatively, classification systems could control for or include additional environmental information to improve classification accuracy. Some studies already implement this, but it requires a detailed understanding of the impact of environmental variables on all species included in the model, which we do not have yet. In all cases, in order to improve classification models’ accuracy in real life conditions, and the chance that we can use them for monitoring purposes, we need to better understand and account for natural variability in the target populations.
Researchers from the HUN-REN Centre for Ecological Research and the HUN-REN Balaton Limnological Research Institute* explored what different people value at Lake Balaton and its shores.
Based on a survey of 1,500 people — including local residents, vacation homeowners, and tourists — the findings show a clear preference for a more natural Lake Balaton, with accessible shores, reed beds, and limited built infrastructure.
While Lake Balaton is Hungary’s most popular tourist destination, it is also a highly sensitive ecosystem. Respondents value not only recreation and scenic beauty, but also key ecosystem services – benefits from nature, such as clean water filtered by reed beds, shoreline protection, and habitats for plants and animals.
Most people preferred close-to-natural shorelines and strongly rejected highly built-up beaches and private resorts closed to the public. Environmental awareness proved to be the strongest factor shaping these preferences — more influential than income, education, or tourism-related work.
A clear majority opposed further intensive development: 58% rejected more hotels, 61% opposed new marinas, and 58% did not want more yachts on the lake.
Overall, the message is clear: people want a future in which nature, public access and long-term ecological health of Lake Balaton are put first.
*This research was performed together with the PAD Foundation for Environmental Justice, the National Laboratory for Water Science and Water Security, the Institute of Applied Water Science, the HUN-REN–BME Water Research Group, and Budapest University of Technology and Economics.
Policy Brief from the EU project RestPoll, provides recommendations on which renaturation measures are most effective in promoting pollinators, such as wild bees, in Europe.
The key messages are more high-quality, interconnected habitats and a reduction in the intensity of highly intensive land use—for example, through the use of fewer pesticides and adapted mowing and grazing systems—are needed.
The results should help EU member states to implement their nature restoration plans under the EU Nature Restoration Regulation (NRR) in an effective, practical, and verifiable manner.
Pollinating insects such as bees, bumblebees, butterflies, and hoverflies play a key role in agriculture, biodiversity, and stable ecosystems. Pollinator conservation measures ensure the yields of many crops and contribute to healthy soils, clean water, and climate protection. At the same time, their populations have been declining in many parts of Europe for years. A new policy brief from the EU Horizon Europe project RestPoll now summarizes which restoration measures, based on current scientific evidence and expert knowledge, can best contribute to the recovery of pollinator populations. The project is led by Prof. Dr. Alexandra-Maria Klein, Professor of Conservation Biology and Landscape Ecology at the University of Freiburg.
“If we want to halt and reverse the decline of pollinators in Europe by 2030, we must consistently address two key issues: the expansion and interconnection of suitable habitats, and less intensive use of intensive agricultural and green spaces,” says Klein. “It is important that measures are adapted to local conditions, developed in collaboration with practitioners, and systematically monitored.”
How the recommendations were created
The policy brief is based on a survey of experts and an overview of the literature. In the first step, 56 internationally recognized pollinator experts from 20 European countries evaluated a total of 17 possible renaturation measures in an online survey. They assessed how effective, practicable, and cost-intensive these measures are based on their professional and practical experience. These assessments were supplemented by a targeted review of the scientific literature, including the use of the Conservation Evidence platform, which systematically evaluates research findings on the effectiveness of conservation measures.
The authors specifically place their recommendations in the context of the EU Nature Restoration Regulation (NRR). Article 10 of this regulation obliges member states to reverse the decline in pollinators by 2030 and to further increase their populations thereafter. EU member states must submit their draft national restoration plans to the European Commission by September 1, 2026.
Which measures are particularly effective in protecting pollinators?
According to the analysis, pollinator protection can be effectively combined with renaturation measures in agricultural landscapes, grasslands, and urban green spaces. The most effective approach is to increase the quality, area, and connectivity of habitats for pollinators. These include species-rich (semi-)natural meadows, wildflower areas, hedges, and flowering trees and shrubs. Such structures not only improve food resources but also facilitate the spread and genetic exchange of pollinators in the landscape.
At the same time, according to the authors, it is crucial to reduce intensive farming practices—for example, by using fewer pesticides and mowing less frequently or grazing less intensively. Fallow land, on the other hand, should be used again in a gentle manner, for example, by mowing occasionally or grazing with a small number of animals to prevent the land from becoming overgrown with bushes. This would create flower-rich areas that would provide food for pollinators and support their protection and reintroduction. There is no “standard solution” here: measures are particularly successful when they are adapted to local conditions such as soil, climate, landscape structure, and target species.
The authors cite clear and measurable goals and advocate for the involvement of farmers, land managers, local authorities, government agencies, and experts. Additionally, sufficient financial and technical support and monitoring to assess whether measures are effective and need to be adjusted are prerequisites for successful implementation. „Pollinator restoration can be both ecologically sound and cost-effective, creating multifunctional landscapes that strengthen pollinator populations while delivering broader benefits for biodiversity, soil and water health, sustainable agriculture, climate mitigation, and community well-being. It can also reduce reliance on chemical inputs, supporting long-term environmental and economic resilience,“ explains Dr. Jessica Knapp, lead author of the policy brief and researcher at Lund University (Sweden).
Original publication:
Knapp, J., Dicks, L., Kranke, N., Morgan, W., Potts, S., Smith, H.G., Stout, J., Thijssen, M., Thompson, A., Klein, A.-M. (2026). Nature Restoration Plans – the most effective measures to restore pollinator populations. Policy Brief from the EU-Horizon-Europe-Project RestPoll (Grant Agreement No. 101082102). Zenodo. DOI: 5281/zenodo.18655302
The policy brief was developed as part of the EU Horizon Europe project RestPoll (funding code 101082102) with the participation of other EU Horizon Europe projects that address the role of pollinating insects in ecosystems and human well-being.
Contact:
Prof. Dr. Alexandra-Maria Klein
+49 (0) 761 203-67770
alexandra.klein@nature.uni-freiburg.de
Photo:
Pollinators ensure the yields of many crops, such as this buff-tailed bumblebee (Bombus terrestris) on the blossom of a sweet cherry tree. (Photo: Felix Fornoff)
Science-based popular booklet on the spread and management of invasive non-native species is now available
The large-scale and continuous introduction of non-native species poses unprecedented challenges to ecosystems, agriculture, livestock production, and human health.
In response to these challenges, the HUN-REN Centre for Ecological Research has published a 60-page science-based booklet entitled Új fajok, új kihívások – Az inváziós fajok terjedése és kezelési lehetőségei Magyarországon (New Species, New Challenges – The Spread and Management of Invasive Non-Native Species in Hungary). The publication was prepared within the framework of the Invasion Biology Division of the National Laboratory for Health Security.
The booklet aims to provide accessible yet scientifically sound guidance on invasion biology, while also offering practical advice on mitigating the impacts of invasive species.
In a globalised world shaped by international trade and intensive human mobility, completely preventing the arrival of non-native species is unrealistic. However, biological invasions are not beyond control: the spread of species can be slowed, and their impacts reduced. Gaining time in this way is crucial, as it enables both ecosystems and human systems to develop effective responses.
The publication presents the stages of the invasion process in detail, from initial introduction through establishment and spread to large-scale expansion. It emphasises that biological invasion is not a single event but a sequence of interconnected stages — which makes early detection and rapid intervention particularly important.
The impacts of invasive species extend far beyond traditional nature conservation concerns. Some species cause significant crop losses; others threaten livestock or facilitate the spread of pathogens and diseases. Managing invasions is therefore a complex societal challenge, requiring cooperation among natural and social scientists, decision-makers, landowners, practitioners, and the wider public. Effective action depends on cross-sectoral collaboration.
The booklet presents non-native and invasive species already present in Hungary, illustrating risks and management options through concrete case studies.
Its conceptual framework is rooted in the concept of One Biosecurity, recognising that invasive species may simultaneously pose ecological, economic, and public health risks. This interdisciplinary perspective integrates human, animal, plant, and environmental health in addressing biological invasions.
Opuntia Foto credit: Anikó CsecseritsPistia stratiotes Foto credit: Barbara Barta
Új fajok, új kihívások (New Species, New Challenges) seeks to raise awareness, foster dialogue, and support long-term, coordinated action against invasive species.
A new, general theory argues it is not about costly or exaggerated show-offs but about the inherent trade-offs between investments and benefits animals (and humans) face when they signal. The work offers a clearer way to understand peacocks, people, and persuasion by accounting both for honest as well as deceptive signals.
For decades, scientists have tried to answer a simple question: why be honest when deception is possible? Whether it is a peacock’s tail, a stag’s roar, or a human’s résumé, signals are means to influence others by transmitting information and advantages can be gained by cheating, for example by exaggeration. But if lying pays, why does communication not collapse?
The dominant theory for honest signals has long been the handicap principle, which claims that signals are honest because they are costly to produce. It argues that a peacock’s tail, for example, is an honest signal of a male’s condition or quality to potential mates because it is so costly to produce. Only a high-quality birds could afford such a handicap, wasting resources growing it, demonstrating their superb quality to females, whereas poor quality males cannot afford such ornaments.
A new synthesis by Szabolcs Számadó, Dustin J. Penn and István Zachar (from the Budapest University of Technology and Economics, University of Veterinary Medicine Vienna and HUN-REN Centre for Ecological Research, respectively) challenges that logic. They argue that honesty does not depend on how costly or wasteful a signal is, but rather on the trade-offs between investments and benefits, faced by signalers.
They explain that signals are not honest because they are costly, instead, honesty evolves when it is beneficial and deception is costly. Previous studies inspired by the handicap principle (refuted by the authors in the paper) misleadingly focused on only the costs of signalling. Yet biological functions, like signalling, cannot be understood in the evolutionary context without their benefits, often realized in the long run.
The new theory, called Signalling Trade-Off Theory, shifts the focus from absolute cost to choice in what to invest. In biology, every organism faces competing demands: investing more in one thing means having less for another. Time spent courting cannot be spent feeding; energy put into bright feathers cannot be used for immune defence. These are trade-offs. And these are also present in economic choices for humans. Crucially, they differ between individuals. A healthy, well-fed animal can afford different choices than a weak or starving one. According to several theoretical studies, signalling trade-offs and not absolute costs define whether deception or honesty evolves.
“Signals, in theory, can be absolutely cost free in terms of immediate energy investment.” – István Zachar, one of the authors explains – “Honesty does not come from how much a signal harms you but from what kind of cost-benefit ratio you can realize with it.” And this trade-off between investments and benefits is defined by the condition of the individual.
According to theory, honest signals arise when these trade-offs respect the true quality of the individual, i.e. are condition-dependent. High-quality individuals get more return from the same investment than low-quality ones. As a result, the best strategy for a strong individual is to signal more, while the best strategy for a weak individual is to signal less. “Both are behaving optimally,” the author says, “but because their trade-offs are different, their signals end up revealing who they are.” This is how honesty is defined.
This perspective helps clear up a long-standing puzzle. An increasing number of studies show that honest signals are sometimes cheap, cost-free, or even beneficial, to produce. Under the handicap view, this was baffling, because honesty was supposed to require wasteful costs. Under the trade-off view, it is what one would expect. What matters is not whether a signal costs something in absolute terms, but whether pretending to be better than you are would push you into a worse overall outcome. Trade-offs apply to cheaters as well, and while they can increase their reproductive success by a fake message, this may severely affect their survival.
The trade-off theory also explains why deception is common. If different quality individuals face the same trade-offs, then nothing stops them from using the same signal. In those cases, mimics, bluffers, and cheats can thrive. “Dishonesty is absolutely not a failure of nature,” – Zachar notes. “It is what you get when the trade-offs that normally separate the different quality individuals disappear or become identical.”
This idea helps make sense of cases ranging from harmless butterflies mimicking poisonous ones to animals that increase their sexual displays when they are near death. In such “terminal investment,” there is little future to protect, so the usual balance between today and tomorrow is gone, and exaggerated signalling becomes worthwhile.
Why does this matter beyond biology? Because the same logic applies to human communication, from advertising to cooperation based on reputation. We all operate under trade-offs (inherited or learnt) between short-term gains and long-term consequences. Signals are reliable when those trade-offs differ across people in ways that make bluffing unprofitable.
“The real question is not ‘how costly is this signal?’” – Zachar says – “It is ‘what would it cost this person, in terms of what else they could have done, to fake it?’”
By reframing honesty in terms of trade-offs rather than waste, the new theory brings signalling back in line with a broader understanding of evolution: organisms are not rewarded for squandering resources, but for allocating them efficiently under constraints. In that light, honest communication is not a miracle. It is a natural outcome of living in a non-quantum biological world where every choice closes off another.
Reference: A general signalling theory: why honest signals are explained by trade-offs rather than costs or handicaps Szabolcs Számadó1,2, István Zachar3,4 & Dustin J. Penn5 Published in Journal of Evolutionary Biology https://doi.org/10.1093/jeb/voaf144
1 Department of Sociology and Communication, Budapest University of Technology and Economics, Egry J. u. 1. H‑1111 Budapest, Hungary 2 CSS-RECENS “Lendület” Research Group, HUN-REN Centre for Social Science, Tóth Kálmán u. 4., H‑1097 Budapest, Hungary 3 Institute of Evolution, HUN-REN Centre for Ecological Research, Konkoly-Thege Miklós út 29-33., H‑1121 Budapest, Hungary 4 Department of Plant Systematics, Ecology and Theoretical Biology, Eötvös Loránd University, Pázmány P. sétány 1/C, H-1117 Budapest, Hungary 5 Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Savoynestrasse 1a, 1160 Vienna, Austria
A new global study published with the defining authorship of HUN-REN Centre for Ecological Research, Institute of Ecology and Botany in Conservation Biology, the leading journal in the field, highlights that many governments still do not fully recognize the contribution of Indigenous Peoples and local communities, and other traditional knowledge holders to the conservation and sustainable use of biodiversity. The researchers examined the two most recent national reports submitted by the 195 state Parties to the Convention on Biological Diversity, amounting to more than 400 reports in total—two reports in the case of some countries—and approximately 58,000 pages of material. Europe stood out in a negative sense: while countries frequently referred to traditional land use practices, many states considered the issues related to Indigenous Peoples and local communities and traditional knowledge to be irrelevant, due to terminological confusion. The timeliness of the study is primarily underscored by the next round of national reports due in 2026, as well as by the fact that the Kunming–Montreal Global Biodiversity Framework states that achieving its goals is impossible without the genuine involvement of Indigenous Peoples and local communities.
Their findings underscore that biodiversity usually thrives in landscapes where communities holding local knowledge can exert real influence over land and resources, and that it often declines where their practices are ignored. Remarkable examples of community-based, careful land use generally remain hidden in official reports, such as Samoan community-managed fisheries, culturally protected forests in Liberia, and traditional hay meadows found across Europe.
“As countries prepare their next national reports due in 2026, genuinely recognizing the contributions of on-the-ground stewards to biodiversity conservation—and ensuring their meaningful involvement in implementation processes—will be crucial to achieving ambitious global biodiversity goals”, Kinga Öllerer, the study’s lead author summarizes.
Only 33 countries articulated clearly both the benefits of Indigenous Peoples and local communities and their traditional knowledge for the conservation and sustainable use of biodiversity, and explicitly referenced contributions to cultivation and domestication in their fifth national reports. By the sixth reporting cycle, this number had nearly tripled to 80, but still representing just over 40% of Parties. Despite this increase, recognition remains low. Moreover, acknowledgment often failed to name the people behind the practices, and direct involvement of IP&LCs in reporting remained rare.
At the largest biodiversity summit ever held, COP16, which took place in November 2024 in Cali, Colombia, Indigenous Peoples and local communities achieved a breakthrough after more than three decades of sustained efforts: they secured a permanent subsidiary body within the Convention, guaranteeing their formal role in its implementation. The event brought together more than 23,000 registered delegates from nearly 200 countries, alongside over 900,000 visitors. Representatives of Indigenous Peoples and local communities from the Americas, Africa, Asia, and Oceania celebrated in traditional dresses, while European delegations included no other community representatives beyond the Sámi. They are Europe’s only officially recognized Indigenous People. At the same time, numerous traditional farming communities play a key role in maintaining Europe’s biodiversity.
How Parties (i.e., ratifying countries) to the Convention on Biological Diversity (CBD) self-reported on the contribution of Indigenous Peoples and local communities (IP&LCs) and traditional knowledge and practices (TK) to the conservation and sustainable use of biodiversity in their (a) fifth and (b) sixth (b) national reports (basemap source: ArcGIS 10.1 [ESRI, 2012] with World Countries Generalized). Table 1 contains scoring details.How Parties (i.e., ratifying countries) to the Convention on Biological Diversity (CBD) self-reported on the contribution of Indigenous Peoples and local communities (IP&LCs) and traditional knowledge and practices (TK) to cultivation and domestication in their (a) fifth and (b) sixth national reports; (basemap source: ArcGIS 10.1 [ESRI, 2012] with World Countries Generalized). Table 1 contains scoring details.The study’s findings mirrored the underrepresentation seen at the biodiversity summit. Europe proved to be a particularly revealing case in the analysis. Many countries documented in detail traditional land-use practices that are crucial for biodiversity—such as extensive grazing, mowing, and small-scale farming—while often denying the relevance of Indigenous Peoples and local communities. Several governments stated that Article 8(j) of the Convention, which addresses traditional knowledge, did not apply to them, arguing that their countries have no Indigenous or “traditional” communities. This was despite their recognition that the ongoing abandonment of these practices has driven biodiversity loss, including shrub encroachment and declines in species richness in grasslands and wetlands. In essence, traditional ecological knowledge is acknowledged, while its holders are rendered invisible.
The study was initiated by Kinga Öllerer under the guidance of scientific advisor Zsolt Molnár (HUN-REN CER IEB Traditional Ecological Knowledge Research Group). Senior researcher Marianna Biró, a fellow member of the group, joined the work together with scientific advisor András Báldi (HUN-REN CER IEB Lendület Ecosystem Services Research Group, group leader), and several international collaborators.
In summary, the study shows that although governments increasingly recognize that local traditional communities and their knowledge make a significant contribution to biodiversity conservation, very few actually involve them in decision-making and reporting processes. The challenge is clear: the success of global biodiversity commitments depends not only on ambitious targets but also on fully acknowledging, respecting, and supporting the knowledge, practices, and roles of Indigenous Peoples and local traditional communities—and on genuinely involving these communities in implementation processes.
Foto credit:
Hungarian traditional herders maintain vast landscapes through extensive pastoral grazing, and their knowledge, experiences and proposals are attracting growing attention, though still not the recognition they deserve. This photograph was taken by a shepherdess, the leader of the Women in Pastoralism group, about her husband and their livestock, and won third prize in a national photography competition on traditional herding (credit: Ibolya Sáfián Lászlóné).
Reference:
Global overview of progress in respecting the contributions of traditional knowledge in biodiversity governance
A recent study authored with the significant contribution of the HUN-REN Centre for Ecological Research, Institute of Ecology and Botany was published with this title in the D1-ranked journal Journal of Environmental Management. Based on a field experiment, the authors demonstrate that under moderate ungulate density, the effect of forest management interventions on woody regeneration is stronger than the effect of ungulate exclusion per se. Over time, within fenced areas, the regeneration of the light-demanding sessile oak is hindered by faster-growing, more shade-tolerant competitors such as hornbeam, whereas outside the fences, under moderate browsing pressure, interspecific competition may be less intense. The seven-year study was initiated by Bence Tóth, Biology–Chemistry Teacher (MA) at ELTE Eötvös Loránd University, and Bence Kovács (Forest Ecology Research Group, Institute of Ecology and Botany, HUN-REN Centre for Ecological Research), and was later continued by Eszter Lilla Szabó, PhD student (Doctoral School of Biology, ELTE Eötvös Loránd University), under the supervision of Péter Ódor. The study highlights the importance of harmonizing forestry and game management practices to ensure the natural regenerative capacity of forests.
Managing natural regeneration in oak–hornbeam forests requires balancing light availability, competition dynamics, and herbivory pressure. Although fencing is often considered indispensable for protecting oak regeneration, our seven-year experiment shows that the influence of browsing exclusion is frequently overestimated. Silvicultural treatments, particularly those altering canopy openness, exerted a stronger effect on the early/mid-term sapling growth than fencing. Yet the study also highlights that maintaining low to moderate ungulate densities is crucial – not only for long-term regeneration success but even for sustaining the conditions under which silvicultural treatments can outperform browsing.
The researchers used the research infrastructure of the Pilis Forestry Systems Experiment to test the interactive effects of forestry and exclusion treatments. Within the framework of this experiment established in 2014, treatments of conventional rotation forestry (namely, micro clear-cutting, retention tree groups and preparation cutting) and of continuous cover forestry (gap-cutting) was compared to control plots in the closed, two-layered oak–hornbeam stand in the Pilis Mts. (Hosszú hill). For seven consecutive years, the researchers followed the browsing probability, survival, and growth of pairs of fenced and unfenced saplings selected and consolidated in the autumn of 2014.
Silvicultural treatments drive early regeneration growth more strongly than browsing – but only when ungulate densities remain controlled
The applied (micro)clear-cutting (which essentially represent areas of final cutting) and artificial gaps resulted in the greatest increases in shoot growth and estimated leaf area across all tree species. This effect is primarily attributable to enhanced light availability and soil moisture conditions. In these treatments, the extent of browsing and overall ungulate impact temporarily increased – as expected given the increased food availability –; however, the survival of the selected individuals remained stable, because ungulate density in the studied landscape is moderate, largely due to the comprehensive game management practices of Pilisi Parkerdő Ltd. Under low to moderate browsing pressure, individuals outside fenced areas have a higher chance of escaping browsing pressure.
According to Bence Kovács, the corresponding author of the article, it is important to emphasize that “this balance is fragile. The finding that forestry treatments had a stronger effect on individual growth depends on a controlled ungulate population.” In regions with higher densities and browsing levels comparable to those observed here (~60% of individuals browsed) can translate into severe growth reductions or regeneration failure. “Thus, the stronger effect of the treatments observed in this study does not mean that oak regeneration is better without fencing under the current landscape structure and browsing pressure, but rather demonstrates that browsing pressure can be managed if ungulate density remains within an ecologically compatible limits”, the researcher adds.
In the case of shrubs, however, forest management treatments and ungulate exclusion had effects of similar magnitude, which on the one hand indicates their sensitivity to browsing (a substantial difference in height growth between fenced and unfenced plots) and, on the other hand, highlights their role in shaping regeneration dynamics among tree species, especially of the target tree species.
Species-specific trajectories reveal competition as a dominant force
Oaks and manna ash benefited from initial browsing protection, but these advantages diminished due to intensified competition from faster-growing and typically shade-tolerant tree species – especially from hornbeam.
Hornbeam’s rapid juvenile growth and architectural plasticity allowed it to overtop oaks in both gaps and clear-cuts, and competitive effects were amplified inside exclosures. Consequently, in fenced areas where oak regeneration or restoration is a key objective, the suppression of competitor species is necessary, an area in which Pilisi Parkerdő Ltd. already has substantial practical experience. Based on the findings of the study, controlling competition is just as important as managing herbivory, and that fencing without subsequent tending is insufficient for ensuring long-term oak success under the framework of continuous cover forestry.
Shrubs, being highly palatable (and therefore most likely to be browsed) responded most strongly to ungulate exclusion, showing the largest differences in height growth between fenced and unfenced plots. As a result, their presence can substantially reduce browsing pressure on target tree species outside fenced areas and, and – under controlled ungulate densities – can indirectly facilitate oak regeneration.
Gap-cutting can rival clear-cutting for oak regeneration
Medium-sized gaps (cca. 1:1 gap diameter to tree height ratio) generated microclimatic conditions that supported oak survival and growth comparable to clear-cuts. This result challenges assumptions that large openings or extensive fencing are necessary for oak regeneration and supports the feasibility of continuous cover forestry approaches. However, the success of gap-based regeneration still assumes ungulate densities low enough to prevent disproportionate browsing pressure.
Temporal shifts: from browsing limitation to competition limitation
A clear transition in growth-reducing factors emerged over the seven years:
Years 1–4: browsing and light availability shape height increment.
Years 5–: interspecific competition – especially from hornbeam – becomes the dominant constraint, particularly in fenced plots.
This reinforces that ungulate exclusion alone is insufficient; regeneration ultimately hinges on managing competition for saplings to escape herbivore reach.
Management implications
The findings support an integrated, adaptive regeneration strategy:
Ungulate population control is fundamental. Only at low to moderate densities can browsing remain compatible with successful oak regeneration and allow silvicultural treatments to dominate growth responses.
Use moderate gap sizes to provide adequate light without excessively attracting herbivores.
Employ fencing strategically and temporarily – primarily to support the earliest regeneration stages.
Conduct targeted tending to reduce overtopping by shade-tolerant competitors.
Retain or support a shrub layer in the forest matrix, which contributes to browsing dilution and enhances stand structural complexity.
“Our study demonstrates that while ungulate exclusion is not the Holy Grail, neither can natural regeneration succeed without effective ungulate population management. Silvicultural treatments exerted stronger early influence on growth, but this advantage was only possible because browsing pressure remained at ecologically compatible levels. Integrating population control, canopy management, and competition regulation provides a robust pathway for achieving resilient oak regeneration under continuous cover forestry across Central Europe.” concludes Bence Kovács.
As small aquatic habitats disappear at an alarming rate, private garden ponds may help compensate for the loss of natural habitats and support biodiversity in urban areas. However, as these ponds become increasingly popular, the spread of invasive species is emerging as a pressing issue.
Ponds, small (<5 ha) standing waterbodies, are among the most common freshwater habitats worldwide, but they are vanishing rapidly due to agricultural activities, urbanisation, climate change, and other human impacts. At the same time, we are creating new, secondary habitats in the form of garden ponds. These artificial ponds provide a range of ecosystem services, offering refuge for aquatic biodiversity, including protected amphibians, and supporting terrestrial species, especially during dry periods. In some regions, the number of garden ponds even exceeds that of natural waterbodies.
Yet the growing number of garden ponds may pose a new challenge for biodiversity. A wide variety of aquatic plants and animals are available through the ornamental trade, increasing the risk of invasive species introductions. Because these ponds are located on private property, researching and monitoring the species they contain, whether native or invasive, can be difficult. Citizen science, which involves the public in data collection, offers an effective way for researchers to gain access to these otherwise hidden habitats and to document their plant and animal communities.
Researchers at the Institute of Aquatic Ecology, HUN-REN Centre for Ecological Research in Hungary, launched a citizen science project to uncover the hidden diversity of garden ponds — the MyPond project. Within this initiative, citizens provided information about the presence of invasive plants in their ponds. Out of 560 ponds surveyed, almost half contained at least one of the six targeted invasive plant species. Water hyacinth (Eichhornia crassipes), considered the world’s worst invasive aquatic plant due to its environmental and economic impacts, was frequently reported. Water lettuce (Pistia stratiotes) and submerged species such as Elodea spp., Vallisneria spp., and Myriophyllum aquaticum were also common.
Some of these species originate from tropical regions, yet they have already established populations in several European countries. In Hungary, current climatic conditions may still limit their spread, but they can survive in thermal waters, and with climate change, the environment may become increasingly suitable for them. So far, it appears that these plants have primarily spread to natural waterbodies through human activity. However, garden ponds often attract waterbirds, which may also disperse seeds or plant fragments beyond garden boundaries.
“Most of these plants are on the EU’s list of invasive species, meaning it is illegal to keep them. Yet participants willingly reported having them,” said Barbara Barta. “Therefore, the main issue seems to be that the general public is not well informed about the threat posed by invasive species. Many people simply don’t realise that the plants they purchase are banned, and that keeping, growing, or exchanging them is an offence.”
The researchers emphasise the importance of environmental education and of engaging both buyers and sellers of aquatic plants used in garden ponds. “We need to take an active role in helping citizens make better choices for managing their ponds,” they said. “Providing a list of alternative, native plant species would be a good place to start.”
Reference:
Barta, B., Márton, Z., Szabó, B., Vad, C. F., Lukács, B. A. and Horváth Z. (2025) “Garden ponds: hidden sources of plant invasions?” Freshwater Biology, e70145. https://doi.org/10.1111/fwb.70145
A new review led by researchers at the HUN-REN Centre for Ecological Research provides the most comprehensive overview to date of urban ponds and their ecological functions. In this work, the authors reveal that even the smallest and most overlooked types – garden ponds – can play surprisingly important roles in maintaining urban biodiversity and ecosystem services, at the same time, contributing to potential disservices.
In the article published in Wiley Interdisciplinary Reviews: Water, one of the highest-ranked journals in its field, the researchers synthesise findings from more than 200 scientific studies. For the first time, they clearly distinguish between the ecosystem role of public urban ponds (such as park or stormwater ponds) and ponds hidden on private properties, garden ponds.
Although garden ponds are often only a few square meters in size, collectively they can form dense aquatic habitat networks within cities – and in some areas, they may represent the only available freshwater habitats for many species. “Most people think of garden ponds – and even larger park ponds – as purely ornamental,” says Dr. Zsófia Horváth, lead author of the study. “But if you add up all those tiny ponds scattered across a city, they form a vast hidden network that provides shelter and food for frogs, insects, and even bats. They are small, but together they matter enormously.”
The review also highlights that urban ponds are double-edged ecosystems: while they provide important ecosystem services such as supporting pollinators, microclimate regulation, and recreation, they can also contribute to ecosystem disservices when mismanaged. These include facilitating the spread of invasive species, increasing mosquito populations, and causing eutrophication-related problems, such as unpleasant odours and elevated greenhouse gas emissions.
Importantly, the authors emphasize that the ecological functioning of garden ponds remains far less understood than that of larger ponds usually situated in publicly accessible areas – both in terms of their services and their potential disservices. Although they likely exist in vast numbers globally, we still know very little about their regional occurrence and how similar or different their roles are from other urban ponds in supporting biodiversity or posing ecological risks.
“Urban ponds are not without problems,” Dr. Horváth adds. “If poorly managed, they can become ecological traps, but with proper care, they can also serve as key refuges for biodiversity and act as multi-functional ecosystems providing important ecosystem services.”
Despite the existence of millions of garden ponds worldwide, their ecological roles and risks remain poorly understood, with most studies to date coming from the United Kingdom. The authors call for citizen science initiatives and urban planning strategies that formally integrate privately owned ponds into the blue-green infrastructure of cities and promote responsible management by educational activities.
“Urban sustainability begins in our backyards,” Dr. Horváth concludes. “Recognizing the ecological importance of garden ponds could fundamentally change how we think about urban nature conservation.”
The study concludes that even the smallest water patches can hold disproportionately high ecological value – a finding that could reshape how cities approach biodiversity and sustainability in the era of climate change.
Animal farming is not only a key driver of rural landscapes and economy but also strongly influences ecosystem processes. In recent decades, traditional management practices have largely shifted toward modern industrialized systems, altering habitats and influencing the abundance and distribution of many species. A new study published in Landscape Ecology shows that livestock farms may also provide favourable conditions for bats.
The research was led by Kriszta Lilla Szabadi (Institute of Evolution) and Sándor Zsebők (Institute of Ecology and Botany), researchers at two different institutes of the HUN-REN Centre for Ecological Research. They carried out passive acoustic monitoring at 199 sampling points across Hungary, including 92 points from 35 livestock farms.
The objectives of the study were to (1) identify the bat species occurring on livestock farms, (2) compare bat activity at farms with other habitats—including cropland, grassland, oak and pine forests, as well as roads and green areas within settlements—and (3) assess how farm characteristics (such as livestock species and herd size) and surrounding landscape composition influence bat activity.
Fotó: Kriszta Szabadi
The most frequent bats detected on livestock farms were urban-adapted species such as the noctule bats (Nyctalus spp.) and pipistrelles (Pipistrellus kuhlii, P. pipistrellus, and P. pygmaeus), recorded at more than two-thirds of the farms. Interestingly, strictly protected forest specialists such as Barbastella barbastellus and other forest dwelling Myotis species also occurred on farms, indicating that these habitats provide foraging opportunities for a wide range of species.
The study found that the activity of several bat species and that overall bat activity was higher on livestock farms than in many other habitats although not higher than along roads or in urban green areas. This suggests that farms share certain similarities with urban environments, a pattern likely reinforced by their proximity to settlements.
Farm characteristics also mattered: P. kuhlii were significantly more active on cattle farms than on horse farms. This may reflect differences in housing and manure management, as horse stables tend to be cleaner, more closed, and more modern. Landscape context played an additional role. The proportion of green areas within the surrounding artificial environment was positively related to noctule bat activity, suggesting that vegetation patches within or near farms enhance foraging and roosting opportunities and help bats to navigate.
Beyond their ecological importance, bats may also provide ecosystem services to farms. A single individual can consume its body weight in insects per night, including hundreds of mosquitoes and other insects. By suppressing insect populations, bats may help reduce livestock stress and disease risks. However, the study also underlines the need for bat-friendly farming practices: maintaining vegetation corridors, preserving potential roosts, and minimizing risks from domestic predators such as cats are all essential.
This research emphasizes that the integration of ecological knowledge into farming practices can strengthen both agricultural sustainability and wildlife conservation.
Reference: Szabadi K. L., Kurali A., Estók P., Görföl T., Froidevaux J. S. P., & Zsebők S. (2025). Bats in livestock farms—effects of farm characteristics and landscape composition on bat activity. Landscape Ecology, 40:179. https://doi.org/10.1007/s10980-025-02196-9
The ecological role of Hungarian grasslands is very diverse: they are important in maintaining biodiversity, but they also play a significant role in agricultural production, water retention, and soil protection. However, they also have a function that is perhaps not known to everyone: they have a significant carbon sequestration capacity. Although this carbon sequestration capacity is smaller than the carbon sequestration of forests per unit area, it is still very significant, especially because grasslands primarily store the sequestered carbon stock not in plant biomass, but in the organic matter content of the soil, and moreover, over a fairly long term.
How long the carbon stored in the soil is stored depends on many factors. One of the most important of these is the activity of the soil microflora, but equally important is the biological activity of the plants in the soil. On the one hand, plants emit significant amounts of CO2 through their roots, and on the other hand, they provide organic matter to microorganisms directly attached to their roots or living in the environment of the roots (rhizosphere), thus increasing the rate of decomposition processes and the resulting CO2 emissions. Soil respiration is made up of these main components which is one of the most significant element of the carbon cycle of ecological systems.
In a research conducted by the MATE and the Centre for ecological research, we examined the functioning of a dry pasture in Kiskunság, primarily the relationship between CO2 taken up during photosynthesis and released through the soil. We were curious about which carbon source primarily determines the amount of carbon released from the soil, the CO2 stored in the organic matter content of the soil, or the CO2 which was “freshly” taken up by plants? Between 2012 and 2020, measurements were taken a total of 23 times at 78 permanent points. The special feature of the area – in addition to being a highly protected by the Kiskunság National Park – is that a measuring station (eddy-covariance micro meteorological station) has been operating here since 2002, which measures the CO2 and water vapor currents between the surface and the atmosphere, making it suitable for measuring the amount of carbon taken up through photosynthesis.
The results of the research were somewhat surprising, as they showed that the amount of carbon actually taken up and released into the soil by plants determined the extent of soil biological activity a much greater extent than the amount of carbon stored in the soil, despite the fact that the carbon content varied in a very wide range (1.1-14%) in the sample area. The fact that photosynthetic CO2 uptake can be just as decisive factor in soil carbon turnover and CO2 emission as the main environmental factors (temperature, soil moisture) was little known until now and may be important information for biogeochemical models. The negligible role of soil carbon content may be explained by the microbial usability of different forms of the carbon pool, as there are fractions that are more and less easily usable by microbes, the amount of which is determined by the physical structure of the soil.
Péter Koncz measures soil respiration
This knowledge is extremely important for understanding the functioning of carbon turnover, especially in view of the accelerating climate change. If the soil and biomass breathe out more CO2 than they absorb then carbon is being lost from the ecosystem. Preserving and maintaining the functions of grasslands is important from environmental, nature conservational and agricultural aspects.
