The resilience of aquatic ecosystems to heatwaves and their ability to recover from changes caused by temperature-induced stress

Researchers from the Institute of Aquatic Ecology of the ELKH Centre for Ecological Research (CER) led by Csaba Vad, conducted a study in an international collaboration to explore the resilience of aquatic ecosystems to the negative impacts of heatwaves. They also investigated whether dispersal from surrounding habitats, i.e., the arrival of other species, could accelerate ecosystem recovery. During their experiment on plankton communities in mesocosms, the researchers found that the heatwave drastically reduced the biomass of plankton due to the negative impact on primary consumer zooplankton, such as water fleas. Dispersal from surrounding habitats had limited effect in this study, somewhat positively influencing only the growth of phytoplankton. As a result of the heatwave, both the composition and trophic structure of the communities changed, which could have long-term implications for ecosystem functioning. The study presenting the results was published in one of the leading international ecological journals, Global Change Biology.

The increasingly frequent and intense heatwaves associated with global climate change pose a significant threat to biodiversity, ecosystem functioning, and the ecosystem services provided to humans. Consequently, it becomes crucial to understand the mechanisms that affect the resilience of communities in the face of extreme temperature events, including their resistance to temperature stress and their subsequent recovery. This knowledge is essential for improved prediction and mitigation of biodiversity loss and its far-reaching implications. Moreover, it enables the application of effective strategies to adapt to climate change.

In a research led by Csaba Vad, researcher at the Institute of Aquatic Ecology of CER, an international research group investigated whether connectivity through dispersal facilitates ecosystem adaptation to heatwave-induced stress (“spatial insurance hypothesis”). The study, conducted over a period of one and a half months, took place in artificial lakes known as mesocosms. In these experimental systems, the processes occurring in natural ecosystems can be modeled much more realistically compared to laboratory conditions. Moreover, they allow for the isolated examination of individual stressors and underlying mechanisms, which would not be feasible in natural habitats due to their complexity.

The Austrian WasserCluster Lunz research institute’s mesocosm system,
where the experiment was conducted

According to the results, the heatwave led to a decrease in plankton biomass, primarily due to its negative impact on zooplankton, such as water fleas. In the case of a natural lake, for example, this could lead to temporary reduction in food sources available for fish or even the development of algae blooms, as these small microscopic organisms play an important role in regulating algae levels. The effect of dispersal from surrounding habitats in this experiment was relatively minor, and it was only evident in the faster post-heatwave growth of phytoplankton. The results showed that the community biomass returned to the undisturbed level regardless of dispersal. However, the composition and trophic structure of the community changed, which could potentially result in long-term alterations in ecosystem functioning.

Based on the experiment, it can be concluded that even a short heatwave of about one week can alter the species composition and interactions within aquatic ecosystems, potentially leading to long-term consequences. These effects can be further aggravated by the fragmentation of ecosystems resulting from habitat loss, increasing spatial isolation of remaining habitats and reducing the dispersal of organisms. Ecologists urge for further long-term research to understand the impacts of heatwaves and develop possible adaptation strategies.

The research was carried out within the framework of the H2020 AQUACOSM project, with the support of H2020 AQUACOSM-plus and the National Multidisciplinary Laboratory for Climate Change.

Photos: Zsófia Horváth


Vad Cs. F., Hanny-Endrédi A., Kratina P., Abonyi A., Mironova E., Murray D. S., Samchyshyna L., Tsakalakis I., Smeti E., Spatharis S., Tan H., Preiler C., Petrusek A., Bengtsson M. M. & Ptacnik R. (2023). Spatial insurance against a heatwave differs between trophic levels in experimental aquatic communities. Global Change Biology 29: 3054–3071. (IF2021: 13.211 | SCimago2022: D1)


The Invasion Biology Division of the National Health Security Laboratory has been established with the leadership of CER as the new center for domestic research on biological invasion

The Invasion Biology Division of the National Health Security Laboratory (NHSL) has recently been established with the leadership of the ELKH Centre for Ecological Research (CER). The primary mission of the participating experts is to assess the level of threat posed by invasive species in Hungary, develop a comprehensive ecological framework to address the issue, and provide practical recommendations to decision-makers based on scientific findings, in order to support the development of effective invasion defense strategies. Additional consortium members of the project include the University of Pécs (UP), the ELKH Centre for Agricultural Research (ATK), the Hungarian University of Agriculture and Life Sciences (MATE), the University of Veterinary Medicine Budapest (UNIVET), and the ELKH Veterinary Medical Research Institute (ÁTKI).

The plant and animal life on Earth has evolved over millions of years. Populations were separated by oceans, mountain ranges, seas, and rivers, allowing each continent and their various geographic units to develop their unique biodiversity characteristics specific to that particular area. Throughout its history, humanity, especially during the age of great geographical discoveries, has intentionally or accidentally introduced and transported plant and animal species to areas where they were not originally native. In recent decades, globalization has led to a significant increase in the intentional introduction of non-native species for economic purposes, as well as the accidental introduction through transportation, travel, or tourism. Some of these species, once escaping human control, start spreading in their new habitats, causing harm to native flora and fauna. The introduction of new species leads to rearrangements in the ecological relationships among members of the original communities, resulting in damage to the composition and functioning of natural ecosystems, and the decline or extinction of numerous native species.

Articles on topics such as the naturalization of introduced plants began to appear as early as the 19th century. However, by the 20th and 21st centuries, the issue had reached such a magnitude that a new field of study, invasion biology or invasion ecology, emerged to address these questions.

Today, terrestrial ecosystems face a dual crisis of climate change and rapid biodiversity loss. One of the main causes of biodiversity loss, alongside systematic habitat destruction and fragmentation, is the spread of invasive species. The typical case of invasion phenomena occurs when a plant or animal species introduced for economic or aesthetic reasons, escapes from its breeding or cultivation area and becomes an “invasive species”, overwhelms the previously diverse native ecosystem. Examples of this include the planting of common milkweed (Asclepias syriaca) or giant goldenrod (Solidago gigantea) as bee pastures, which have caused severe degradation and destruction of our protected and natural grassland areas by today.

However, the range of invasion phenomena is much broader than that. Nowadays, we are familiar with numerous examples where introduced or spontaneously established species act as vectors, carrying new pathogens that can cause previously nonexistent diseases in the given area and potentially lead to epidemics. In recent years, for instance, several invasive mosquito and tick species have appeared in Europe, capable of transmitting various pathogens, including viruses and nematodes, that pose risks to both humans and domestic animals, causing a range of human diseases and conditions, as well as for example heartworm in dogs. The agricultural sector faces a new challenge with the impact of invasive plants on pollinator communities or the appearance and damage caused by invasive sucking pests, mites, and bugs, for example in vineyards and orchards, significantly reducing the efficiency of agricultural production.

Biological invasion is therefore a complex issue that not only directly affects biodiversity loss, but also has a direct impact on various segments of the economy and society, the decline of natural habitats, the reduction and disappearance of native species, the efficiency of agricultural and forestry practices, and ultimately, human health. It leads to the loss of natural and healthy environments and directly contributes to the emergence of new pathogens or allergens.

The severity of the impacts occurring on multiple levels is indicated by the fact that the European Union spends over 12 billion euros annually on combating invasive species and mitigating the damages caused by them, and this amount continues to increase year after year. According to the latest global assessment by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the number of invasive species per country has increased by 70 percent since 1970, and over one-third of the currently recorded invasive species have appeared for the first time in a biogeographic region outside their native range in the past four decades. Globally, Europe and North America have the highest number of invasive species, and Hungary is also considered an invasion hotspot. Hundreds of new species have emerged in the past century in the country, many of which have caused significant ecological changes.

The phenomena related to biological invasion are intensively studied by representatives of various disciplines, including ecologists, virologists, plant protection experts and medical professionals. However, there are still numerous unanswered questions in each subfield. Currently, it is not yet possible to predict invasive processes in the same way as, for example, different climate scenarios show the expected outcomes under varying conditions.

As part of the Széchenyi Plan Plus program, the Invasion Biology Division of the National Health Security Laboratory has recently been established with the support of project RRF-2.3.1-21-2022-00006. The Invasion Biology Division, operated by a consortium led by CER and comprising PTE, ATK, MATE, UNIVET, and ÁTKI, aims to assess and address the actual threat posed by invasive species by developing a unified ecological framework and providing effective practical solutions based on scientific findings.

During the research, experts map and document the appearance and spread of – what based on their societal impact are considered – key invasive species in Hungary, including invasive plants, mosquitoes, plant pests, and wildlife. Understanding the process and driving forces of invasion is crucial for comprehending the effects, predicting invasions, and developing defense strategies. The properties determining the spread success of invasive species, including the contribution of human mobility to their spread, are investigated integratively in experimental systems. The impacts of invasive species on native species, ecosystem functioning, and ecosystem services are also studied. To understand the social and economic consequences of invasion, participating experts collaborate with relevant stakeholders to examine the effects on agriculture, forestry, game management, as well as plant, animal, and human health. A key objective of the project is to develop new technologies based on research findings, using predictive models, artificial intelligence, and molecular methods, to identify and forecast critical invasive events. The development and testing of new methods for invasive species control are also part of the plan.

The members of the Invasion Biology Division of NHSL consider providing continuous comprehensive information on the scope of invasion and the actual level of risks to the wider public, as well as formulating recommendations for decision-makers to develop invasion defense strategies, as their key task.


Researchers do not recommend planting blanketflower in gardens due to its invasive potential

The researchers of the ELKH Centre for Ecological Research (CER) investigated the spread of the non-native great blanketflower in Hungary within the framework of the National Laboratory for Health Security project. The aim of the research was to evaluate the impact of the species on the local plant community and determine its invasive potential through its functional traits. Based on the results, the great blanketflower does not currently appear to be a strong ecosystem-transforming species, but there is a risk that due to climate change, the local environment in Hungary will become more suitable for it in the future, leading to strong speading and becoming invasive. Therefore, the researchers do not recommend planting blanketflower species in gardens. They also suggest surveying non-native ornamental plant populations, conducting long-term monitoring and a more detailed assessment of the traits that influence their spread. The publication presenting the results was published in the scientific journal NeoBiota.

Ornamental plants are one of the main sources of species becoming invasive. During their planting, they are introduced to new habitats where humans create favourable living conditions through irrigation and maintenance. Later, in natural habitats, they can easily occupy open niches created by human disturbances and the warming effects of climate change. The blanketflower has followed this path as well, and its ecological impacts were studied by researchers of CER along with several other new, potentially dangerous species within the recently initiated National Laboratory for Health Security project.

The great blanketflower and its relative, the Indian blanket, along with their hybrid, are globally planted ornamental plant species. Reports have already been made in several countries about the great blanketflower escaping from gardens and naturalizing in various new habitats, but its invasive behavior has been relatively unknown until now. However, it seems that in the past few decades, this species has found suitable habitats in Hungary and from a naturalized species it has become invasive in several locations. “Our aim was to map the distribution of the great blanketflower in Hungary, evaluate its impact on the local plant community, and determine the species’ invasive potential through its functional traits,” summarized Gabriella Süle, Phd, a assistant research fellow at CER.

Based on the distribution data collected here, the great blanketflower occurs in Hungary mainly as casual escapes yet. This species, which blooms profusely throughout the year and is extremely colorful, requires little to no care. Therefore, owners allow it to spread, and we can often see it occupying more and more space in front of gardens. However, it became naturalized in recent years, and invasive populations have also been found in significant numbers within the country. The species is mainly observed near gardens and disturbed habitats, but it has also appeared in natural and semi-natural grasslands. It successfully spreads in disturbed, species-poor, sandy, open habitats. Its spread affects the composition of the local plant community, reducing, for example, the species richness of local plants. Based on its functional traits, its well germination capacity, extremely long flowering period, the large absorbing and adhering surface provided by its roots, and its spread by grazing animals’ fur, mainly sheep, can promote its invasive spread. Currently, the great blanketflower does not appear to be a strong ecosystem-transforming species, but more attention needs to be paid to it because there is a risk that the local environment in Hungary will become increasingly suitable for it due to drier weather caused by climate change, leading to strong spread and becoming invasive, primarily in sandy soils.

“Due to all of these, we do not recommend planting blanketflower species in gardens, as they can easily escape and establish in natural plant communities. Furthermore, we suggest considering banning their distribution in seed mixes. To control invasive populations in natural habitats, there is a need to develop an effective eradication method” emphasized Gabriella Süle, Phd.
Assessing the great blanketflower and similar non-native ornamental plant populations, conducting long-term monitoring, and performing a more detailed evaluation of the traits influencing their spread would be important in order to prevent the escape of species planted in gardens into the natural habitats on time.

Assessing and managing the ecological, economic, and societal threats posed by invasive species similar to the great blanketflower is one of the focuses of the Division of Invasion Biology within the National Laboratory for Health Security project. The research is being carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF-2.3.1-21-2022-00006 project.

Süle G, Miholcsa Z, Molnár C, Kovács-Hostyánszki A, Fenesi A, Bauer N, Szigeti V (2023) Escape from the garden: spreading, effects and traits of a new risky invasive ornamental plant (Gaillardia aristata Pursh). NeoBiota 83: 43-69.

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Researchers have revealed the multi-level effects of invasion on plant-pollinator communities

Researchers from the ELKH Centre for Ecological Research (CER) and Babeș-Bolyai University (BBE) in three recent papers have described the effects of twelve invasive plant species with different traits on vegetation (Fenesi et al. 2023), pollinator communities (Kovács-Hostyánszki et al. 2022), and the traits of pollinating insects (Szigeti et al. 2023). During their field studies they assessed and compared the plant and pollinator communities of invaded and semi-natural habitats in Hungary and Romania. In order to facilitate proper comparisons and conduct detailed exploration, the researchers employed uniform field methods while utilizing diverse ecological indicators, ranging from the height of indigenous vegetation, honeybee abundances, depth of flowers to tongue length of pollinator insects.

Bees and other pollinator species play an extremely important role in most terrestrial ecosystems, including agriculture. Increasingly, studies report the drastic decline of pollinating insects, one reason being the reduced availability of their food resources. The strong spread of invasive species is one of the five most important causes of biodiversity loss, that is why the Invasion Biology Division was established under the leadership of the Ecological Research Center within the National Laboratory for Health Security, where researchers investigate the complex effects of invasion. Where invasive plant species appear and are able to spread, they inundate and dominate the given area, reducing diversity and making habitats more homogeneous. In many cases, they also reduce the range of available flowers, thus helping some compatible pollinator species while displacing the food resources of others from the landscape. In general, it can be stated that the impacts of invasive plant species on native vegetation and pollinator insects are often varied and dependent on their specific traits.

Based on the research results, there is no universal effect of plant invasion, except for a few general patterns there are differences among invasive plant species in almost every ecological indicator studied. Perhaps the most important message is that as many invasive plant species and traits as there are, there can be a variety of effects on invaded plant-pollinator communities. The three publications highlight that the cover of invasive plant species strongly influences the composition, diversity, and height of the remaining native vegetation, among other factors. As the invasive plant species displaces native plants in a given area, fewer of the original or potential communities remain. Perennial invasive plant species have an even stronger negative impact on flower availability and pollinators than annual species. This is likely due to their stronger invasive capacity, dominance, different growth and flowering strategies, and presence in later successional stages of habitats. Timing is extremely important in plant-pollinator systems. Invaded areas are similar to crop fields such as rapeseed or sunflowers: during their blooming period, they provide significant amounts of food for the pollinating insects, while beyond of their flowering period, these areas are extremely poor in resources of pollinators. Where invasive plant species appear, they eventually become dominant. They cover the area with green vegetation mass for most of the year, but only bloom for a short period of time. As indicated by the studies, natural areas have more and more diverse resources along the year. The researchers also found important and interesting relations when comparing the traits of invasive flowers and the traits of wild bees. For example, the sites invaded by two invasive species with deep flowers had more long-tongued and also larger-bodied bees, while a species with shallow flowers had more smaller-bodied bees. This indicates a strong size determination between flowers and their pollinators, meaning that the invasion of a particular trait (such as deep flowers in invasive plants) affects the functional characteristics of the remaining pollinator community in the invaded area (i.e., only long-tongued pollinators that can feed on deep flowers will remain).

Proper nature conservation management of (semi)natural habitats and effective control of invasive plant species are important for the protection of pollinators, but some invasive plants can also provide valuable foraging resources for pollinator insects. Therefore, instead of uniformly eradicating all invasive species, it is recommended to consider the best approach on a case-by-case and location-specific basis, taking also into account the needs of protected pollinator insects. For example, efforts to combat plant invasion could incorporate the nutritional requirements of pollinators. Some of the costs associated with invasive plant eradication could be redirected towards providing alternative nutrition sources, such as sowing native seed mixes in or in the neighborhood of invaded areas. Overall, the factors and impacts important in the plant-pollinator systems are complex and interrelated, hence further detailed studies are needed to uncover the specific relationships between species and to develop effective conservation solutions.


Fenesi, A., Botta-Dukát, Z., Miholcsa, Zs., Szigeti, V., Molnár, Cs., Sándor, D., Szabó, A., Kuhn, T., Kovács-Hostyánszki, A. (2023). No consistencies in abundance-impact relationships across herbaceous invasive species and ecological impact metrics. Journal of Ecology. DOI: 10.1111/1365-2745.14085

Kovács-Hostyánszki, A., Szigeti, V., Miholcsa, Zs., Sándor, D., Soltész, Z., Török, E., Fenesi, A. (2022). Threats and benefits of invasive alien plant species on pollinators. Basic and Applied Ecology, 64:89–102. DOI: 10.1016/j.baae.2022.07.003

Szigeti, V., Fenesi, A., Botta-Dukát, Z., Kuhlmann, M., Potts, S. G., Roberts, S., Soltész, Z., Török, E., Kovács-Hostyánszki, A. (2023). Trait-based effects of plant invasion on floral resources, hoverflies and bees. Insect Conservation and Diversity. DOI: 10.1111/icad.12640

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Invasion Biology website launched

The website of the Division of Invasion Biology, part of the National Laboratory for Health Security, has been launched at

The main mission of the Division is to investigate the ecological causes and consequences of the establishment and spread of invasive species through a unified concept, which requires a systemic and cross-disciplinary investigation of the processes at the system level and in distant specialist areas. In total, 16 research groups from six institutions are involved in this work, and one of the main aims of the website is to present the groups and the research topics they investigate, as well as to provide regular updates on the latest scientific publications and professional events published within the Division of Invasion Biology. We consider it important to make our latest scientific results in the field of invasion biology easily accessible in one place and in a suitable format for both professional and civil audiences, thus ensuring their further exploitation.


Tree plantations are weak substitutes for near natural forests

Over the past two centuries, in Hungary and globally, the area of natural and semi-natural forests shrunk dramatically, while at the same time some of the economic functions of forests have been taken over by tree plantations, which cover a significant area (3.8% of Europe’s forests but in Hungary in some region e.g. Kiskunság this proportion exceeds 80%). Plantations are intensively managed forests, mainly composed of one or two tree species, which mainly perform economic functions (e.g. timber and firewood production). There is a long-standing controversy about the evaluation of tree plantations, depending on whether the economic or the nature conservation values of the forest are regarded as a primary role. While tree plantations can also provide some important ecosystem services alongside the economic benefits of timber production, in these ‘forests’ taxonomic diversity decreases radically or the plantations become a hot spot for biological invasions.

A paper of the researchers of the University of Szeged and the Centre for Ecological Research, published in Forest Ecology and Management, represents a significant step forward in the more accurate ecological assessment and evaluation of Hungarian tree plantations. The sample area was the Kiskunság Sand Ridge, a lowland region in the center of the Pannonian biogeographic region between the rivers Danube and Tisza in Hungary, where semi-natural forests survived almost exclusively in the forest-steppe mosaics of protected areas, but tree plantations are widespread in the landscape. The analysis compared four types of forest habitat: near-natural poplar forest Junipero-Populetum albae and three types of tree plantation: native deciduous white poplar (Populus alba), the non-native deciduous black locust (Robinia pseudoacacia), and the non-native evergreen Austrian pine (Pinus nigra) plantation. The study assessed the diversity of the vegetation, not only in terms of species diversity, but also in terms of functional and phylogenetic diversity indicators, i.e., how diverse the vegetation is in each type in terms of plant traits (pollination type, seed dispersal, life form, flowering date, etc) and phylogenetic lineages. Each type of habitat was assessed from an ecological and conservation point of view based on the occurrence of protected, endemic and red-listed species, i.e. the rarest and most valuable species from a conservation point of view.

László Erdős, a research fellow at the Centre for Ecological Research and one of the lead authors of the paper, says that each forest type has a unique species composition, but semi-natural forests are the richest in native species, while tree plantations are dominated by weeds and non-native species. The semi-natural forest is also characterized by the frequent occurrence of native shrub species such as Berberis vulgaris, Ligustrum vulgare, and Rhamnus catharticus. In the case of tree plantations, shrubs disappear as a result of the forestry activities (mechanical site preparation and mechanical weed control) to protect the saplings. The planted tree species also have an impact on the forest floor, e.g. in Robinia pseudoacacia stands weed species that tolerate high nitrogen levels appear, or in pine forests, the deep layer of slowly decaying leaf litter results in a special species composition.
The analysis also showed that low taxonomic diversity in tree plantations does not necessarily imply low functional or phylogenetic diversity, as several different diversity indicators provide a more complex characterization of the plant diversity of a habitat. Among the tree plantations, native poplar plantation and pine forest were found to be more favorable habitats for plant diversity than black locust stands. Black locust was also the most degraded of the habitats studied in terms of naturalness indicators.

The study provides a more accurate assessment of the different types of tree plantations in the region and has important implications for forest management and conservation. From an ecological and conservation point of view, the remnants of semi-natural forest are much more valuable than any of the tree plantations, and therefore conservation and restoration programs should focus primarily on these areas. Of the tree plantations, the planting of native white poplar (Populus alba) should be preferred when further tree plantations are to be established. In the longer term, reducing the area of black locust and pine plantations is inevitable, and the establishment of a mosaic of grassland and forest, in keeping with the semi-arid climate of the Kiskunság, is appropriate for the forest-steppe region.

Khanh Vu Ho, György Kröel-Dulay, Csaba Tölgyesi, Zoltán Bátori, Eszter Tanács, Miklós Kertész, Péter Török, László Erdős: Non-native tree plantations are weak substitutes for near-natural forests regarding plant diversity and ecological value Forest Ecology and Management, Volume 531. 2023.

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Alkaline soda wetland restoration in Apaj-Puszta on the World Wetlands Day

World Wetlands Day is celebrated each year on 2nd February to raise awareness about wetlands. This day also marks the anniversary of the Convention on Wetlands, which was adopted as an international treaty in Ramsar, Iran, on this day in 1971. To mark this occasion, the Ministry of Agriculture organised a celebration event in Dömsöd on 2nd February 2023, jointly with the Szomor Eco-Farm and the Hungarian National Committee of the Ramsar Convention.
The Centre for Ecological Research was represented by Dr. Emil Boros, Senior Research Fellow of the CER Institute of Aquatic Ecology and member of the Hungarian National Committee of the Ramsar Convention. In a joint presentation with Dezső Szomor, – ecological farmer and head of Szomor Ecofarm (who is also a member of the Ramsar Committee), – he evaluated the reconstruction over the past 30 years of the Apaj alkaline soda wetland of international importance, which is part of the Kiskunság National Park and registered as a Ramsar site and presented the related LIFE Nature project.
Based on his decades of research the ecologist presented in detail the results of the 500 ha experimental wetland restoration project established and run by Szomor Ecofarm in the Lower Szúnyogi Meadow in the Apaj Basin.
“The essence of this scheme is to reconstruct the functioning of the floodplain wetland system of the ancient Danube valley plain in accordance with the current landscape conditions, where sustainability is ensured by the fish pond system connected to the water system and operated by Szomor Eco-farm. The conservation-ecological specificity of the water system is that the fishponds and natural wetlands fed by the Danube water are directly supplied with water through local gravity flow systems below the surface, which indirectly ensures the adequate quality and quantity of water supply for the alkaline soda wetlands. The Apaj-Puszta wetland restoration project is therefore an important reference site in the region for the restoration of alkaline soda wetland habitats, which are unique on a global scale. In addition to flooding, the Szomor Eco-farm is implementing the conservation management of the temporary alkaline soda wetland through extensive grazing of buffalo and Hungarian grey cattle,” said Emil Boros.

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New Handbook about Invasive Animal Species in Hungary

After a gap of nearly two decades, the first comprehensive summary volume on all invasive animal taxa in Hungary has been published. The publication is available (also in English) in the Rosalia Handbooks series of the Danube-Ipoly National Park Directorate.

Despite the fact that the spatial expansion of invasive alien animal species is now a major threat to our aquatic and forest ecosystems, there has been no book that would have started to put even a species lists together, let alone gather all the knowledge available from researchers and experts concerning different taxa. This enormous work was carried out by 36 specialists, experts in each taxonomic group. Several researchers from the Centre for Ecological Research have co-authored the volume, with Péter Borza co-authoring the chapter on Peracarida, and Zoltán Soltész, Zsolt László Garamszegi and Edina Török co-authoring the chapter on Diptera species.

In this volume, the authors present species that are primarily cause an ecological problem in their new habitat, but as the descriptions show, there are several species that do have a major or even catastrophic economic impact. The book contains detailed descriptions of the 118 species that have already occur in Hungary or will inevitably do so in the near future, as well as brief descriptions of 4 amphibian and 32 species of terrestrial snails. A general conclusion of the present volume is that our natural waters are especially vulnerable as more than half of the species dealt with within the book occur in aquatic habitats.

Photo: Imre Potyó (Chaetogammarus ischnus)

Source: Rosalia Handbooks 5. Invasive Animal Species in Hungary


Traditional knowledge is local, but pastoralist’s principles are global

The understanding and importance of traditional ecological knowledge systems is increasingly recognised worldwide as a means to develop more effective policies in today’s crises, e.g. in nature conservation or grassland management. Zsolt Molnár, scientific advisor at the Centre for Ecological Research, has been researching the traditional ecological knowledge of pastoralists for more than 20 years. His Iranian student is the first author of a joint publication with European, Asian and African authors in the Journal of Environmental Management.

Unusual for academic publications, the publication is a collaboration between researchers and practising pastoralists. “Since the holders of traditional knowledge are mostly not researchers but herders, farmers, fishermen, when a researcher works with their knowledge, the ethical approach is for these ‘non-scientific’ professionals to also become co-authors. After all, the new publication is the result of collective thinking, knowledge co-production. Such recognition of traditional knowledge is now, fortunately, becoming more and more common” – said Zsolt Molnár.

Herders often graze in landscapes that are less suitable for crop production due to climatic extremes or soil conditions. Traditional grazing systems exist in very different natural environments, such as tundra, steppe, savannah, desert, mountainous areas. Pastoralist communities have locally relevant, multi-generational traditional ecological knowledge of pasture plants on which they base the utilisation of their pastures.

During the research, the authors collected the knowledge of herders on pasture (and hay meadow) plants and plant-livestock interactions in a review article. They analysed 24 of the 372 relevant scientific articles and 18 of the 105 videos about herders and their pastures. In addition, semi-structured interviews were conducted with practising herders in Iran, Mongolia, Kenya, Poland and Hungary to discuss the findings and conclusions.

Thirty-five indicators were identified in the scientific papers and documentaries of how herders ‘see’ forage plants. These indicators described both the botanical features of the plants and the livestock behaviour during grazing, as well as the impact of forage plants on the condition and health of livestock. The indicators were used by herders in management decisions to optimise grazing, the availability and quality of fodder grasses, and the appropriate way of grazing. Although herders around the world are very different, their knowledge of pasture grasses and the relationship between livestock and forage plants is remarkably similar. The researchers identified ten general principles that were common globally, almost regardless of location or habitat type. Such a global synthesis has never been done before.

Perhaps the most important key global principle is the livestock-centred approach explained Zsolt Molnár: “herders see plants through the “mouth of the livestock”. While in the pasture together, herders and livestock reciprocally learn from each other. The condition of the pasture grasses is closely monitored by the herders, who graze each patch in a targeted way, while often planning livestock movements with surprisingly strategic attention to detail, on a daily, weekly and monthly basis. The aim is to make the best use of the available grass as a resource and to ensure also the long-term ‘well-being’ of the pastures (see more details in this film). The lexical details of this knowledge are of course highly specific to the place, but the principles are globally general. You might ask that it’s good, but why is it important? It may come as a surprise, but even in cases where the state or a national park develops supporting measures and regulatory systems for pastoral grazing, it is easy to develop rules that have harmful effects. Because decision-makers often do not sufficiently understand the pastoral world, which is so different from our own. Our article points out that there are general principles that we can build on, and that we can take into account to create better policies, both ecologically and culturally.”

Researchers hope that a better understanding of pastoralists’ knowledge of grasslands and livestock grazing will help not only to maintain the biodiversity and economic benefits of less productive semi-natural grasslands, but also to innovatively preserve the traditional pastoral way of life.

Hungarian team applies game theory to determine how a government can fight novel pathogen

Current Science Daily talked with co-author Ádám Kun how the researchers came up with using game theory as a way to help a government most efficiently deal with an epidemic caused by a new pathogen. Kun is at the Institute of Evolution, Centre for Ecological Research and Eötvös Loránd University in Budapest.
The work appears in Nature’s Scientific Reports, Sept. 30.

Two findings of note.
• First, the study found that the “presence and length of a pre-symptomatic infectious state of the disease” has the “greatest effect” on the probability of the pathogen to cause a pandemic.
• Second, surprisingly, the research showed that even if a nation (or state) wants to provide care for everyone who needs it and “minimize the cost of lockdowns,” it should not “strive for the great expansion of its health care capacities….”

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Appointment of Deputy Director

On the recommendation of the Director of the Institute of Aquatic Ecology, the Director-General of the Centre for Ecological Research appointed Péter Dobosy as Deputy Director of the Institute of Aquatic Ecology from 1 November 2022. His areas of expertise include the chemical analysis of sediment and water in river, lake, wastewater and drinking water, and the study of the effects of trace element-enriched irrigation water on plant cultivation through soil-plant interactions.


International Meeting for PhD students in Botany organized by the CER IEB researchers

Between 22-25 September 2022, the researchers of the Centre for Ecological Research Institute of Ecology and Botany (CER IEB), and members of the Hungarian Ecological Society (HES) organized an International Meeting for PhD students in vegetation ecology in Poroszló, Hungary. This meeting was first initiated by Milan Chytrý and Zoltán Botta-Dukát about twenty years ago, and it has been a very nice tradition since then. Every second year, PhD students in botany meet somewhere in Central Europe and they share their research plans and results, and they can get advice from each other and from senior scientists in a friendly atmosphere.

After a break of few years due to the pandemic, finally this nice event could be organized in person. We were very happy that this year, researchers from the IEB CER – Zoltán Botta-Dukát, Balázs Deák, and Orsolya Valkó – had the possibility to organize this event.

There was a huge interest as there were almost 70 participants, from 16 countries. The scientific program was very intensive, but also very interesting; the PhD students gave very impressive and high-quality presentations, followed by fruitful discussions. The venue of the conference was in Poroszló, in the Tisza-Lake Ecocentrum, which is a wonderful place for such an event. During the coffee breaks, we could visit the nice indoor and outdoor exhibitions and aquariums, which was a nice and refreshing activity. After dinner, there were two very interesting topical discussions about ‘How can we translate the scientific results into practice?’ and whether ‘Quality or quantity counts more in science?’, followed by a lively social program. On Sunday, Balázs Deák led a half-day long excursion, where we showed the participants the natural beauties of the Hortobágy National Park, the alkaline grasslands and wetlands, loess grasslands, and kurgans.

The event was co-organized by Centre for Ecological Research Institute of Ecology and Botany and the Hungarian Ecological Society and supported by the Hungarian Academy of Sciences; we are grateful for its support. We are thankful to all the participants for their enthusiasm and active participation in all the events. We are thankful for all the colleagues from IEB who helped us in the organization, especially József Nagy, Attila Lengyel, and Miklós Kertész. We are thankful to the Hortobágy National Park Directorate for supporting the field trip.

Organizers: Zoltán Botta-Dukát, Orsolya Valkó and Balázs Deák


New ’Forefront’ project at the Centre of Ecological Research

The research project of Orsolya Valkó (CER, IEB, ‘Lendület’ Seed Ecology Research Group) was one of the ten funded Forefront projects by the National Research, Development and Innovation Office in 2022. The research funding will enable the applicants to carry out a world-class research project in Hungary over the next five years, and support the participation in the European Research Council (ERC) research funding programmes. The current project is the third Forefront project at the CER, after the projects of Eörs Szathmáry and Péter Batáry.

The title of the project is ‘Grassland restoration based on nature-based solutions in agricultural landscapes: drivers at micro- and macro-scales’. The topic of the project align well to the current global and European policies, that have ambitious plans for supporting habitat restoration in agricultural landscapes. The Frontline project aims to provide a comprehensive framework for utilizing nature-based solutions in the restoration of semi-natural grasslands and in creating multifunctional agricultural landscapes. The ambition is a multi-scale and multi-site research program that by answering theoretical ecological questions provides evidence-based solutions for strategic restoration planning and for fine-tuning the agri-environmental schemes. The novelty of the work is that the researchers will combine approaches of large-scale multi-site vegetation surveys with landscape ecology, seed ecology and historical ecology. First, they use a multi-site chronosequence approach and study the spontaneous and assisted grassland recovery in agricultural landscapes. They sample the vegetation in 300 recovering sites and evaluate diversity and species composition patterns as a function of small-scale environmental heterogeneity, landscape context and recovery time. In Second, they analyze the temporal (seed bank) and spatial (seed rain) components of seed dispersal and test the effect of the local and landscape factors on the availability of seed sources. Finally, they study whether seeds from the seed sources can achieve successful establishment in the aboveground vegetation and test the importance of plant functional traits, landscape- and environmental filters in the establishment process from the seed sources in the recovery process. They aim to develop and test seed-based restoration methods for overcoming establishment limitation. The research will identify optimal settings of local and landscape factors where recovery is the most promising and support restoration prioritization by determining where we can rely on spontaneous recovery processes and where we need active restoration measures.


Zsolt Molnár elected member of Academia Europaea

Zsolt Molnár, DSc, ethno-ecologist, scientific advisor of the Centre for Ecological Research and head of the Traditional Ecological Knowledge research group, has been elected a member of Academia Europaea.
The Academia Europaea is a non-governmental association acting as an Academy. Its mission is to promote excellence in the humanities, law, economics, social and political sciences, mathematics, medicine and natural sciences and technology. Founded in 1988, it currently has 4,500 members, including 72 Nobel laureates.

Source: Academia Europaea membership


A research group led by fellows from the Centre for Ecological Research summarized spatial priorities for freshwater biodiversity in Europe

A research group led by fellows from the Centre for Ecological Research created a comprehensive analysis on the freshwater biodiversity of Europe. They prioritised water catchments based on the conservation value of the species living there. They found that most of the catchments with high conservation priority are located in the Mediterranean Peninsulas but Hungary is also in the top. The study was published in the journal PLOS ONE.

Although freshwaters cover only one percent of the Earth’s surface they host ten percent of the known species. Freshwater ecosystems provide many ecosystem services such as food production, carbon sequestration or water purification. At the same time, freshwater biodiversity declines much faster than terrestrial and marine biodiversity due to habitat destruction, hydromorphological alteration, hydropower construction, pollution or climate change. These processes are further aggravated with the phenomenon that freshwaters are less involved in protected area designation.

For the more efficient protection of freshwater biodiversity, an international research group led by fellows from the Centre for Ecological Research created a comprehensive analysis ranking water catchments by their priority level. They also investigated priority values in the light of spatial protectedness. They used 18816 freshwater catchments as planning units in the analysis and summed the number of species living in them based on the database of the International Union for the Conservation of Nature (IUCN). There were 512 fish, 656 mollusc, 124 dragonfly and 339 plant, namely a total of 1631 species used in the study. The species were ranked differently based on their IUCN Red List Status and range-restrictedness.

The researchers used methods from the area of systematic conservation planning (SCP). The reason for SCP is to give a scientifically sound basis for the designation of protected areas. One important part of this process is spatial conservation prioritisation where planning units, such as standard sized cells or water catchments are prioritised based on their conservation or other socio-economic importance. In the dawn of nature conservation most of the protected areas were created in scenic, but otherwise hardly cultivatable places such as the World’s first national park, the Yellowstone, or Hungary’s first national park, Hortobágy. In recent times the focus shifted towards the conservation value of species and ecosystems and it is possible to prioritise a large set of planning units with algorythms. One such example is Marxan which was developed to help the rezoning the Great Barrier Reef National Park in Australia. This method is also useful in the validation of existing protected areas.

In this analysis the researchers also used Marxan to prioritise catchments in Europe. They revealed that higher priority values are occuring in the Mediterranean Peninsulas and as well as along major rivers, such as the Danube, while values are decreasing towards north. They also investigated priorities with the involvement of catchment connectivity. In river conservation it is important to give emphasis on connectivity as different influences and threats can react elsewhere from its source due to the connectedness of river sections. They found that although it is important to involve river connectivity it may follows a decreased attention towards lakes and lake species when there is a limited possibility for conservation. When they analysed the relation between areal protection and priorities they found that correspondence is good in Western and Northern Europe mostly due to the Natura 2000 network in the European Union. In contrast, protection level is low in the Non-EU states in the Balkan Peninsula and large parts in the Ukraine and Russia.

Fig 1: Conservation priority of catchments in Europe without connectivity (A) and with connectivity (B). Catchments with orange are more valuable while with grey are less valuable.

Fig 2: Average conservation priority of European countries.

Fig 3: Correspondence between the priority of catchments and their protectedness without connectivity (A) and with connectivity (B).

Photo: A river with high priority values but low protection, Shala in Albania (photo: Márton Szabolcs).


The role of microbial cooperation in the development of higher level organisation

István Zachar and Gergely Boza, researchers of the Institute of Evolution, ELKH Centre for Ecological Research (ÖK) investigated the role of cooperative interactions among microbial cells in the development of higher levels of organisation. They identified the selection forces that facilitate or inhibit microbial community formation, reproduction and the possible emergence of higher levels of selection and evolution. The study of their results has been published in the prestigious international journal Frontiers in Ecology and Evolution.

Microbial communities consist of unicellular organisms, often of species from different domains eukaryotes, bacteria or archaea. Examples are biofilms, the common lifeform of prokaryotes, that form on any surface, on rocks in riverbeds, on the roots of plants, on the skin of animals and humans, or on the inner surface of the digestive system. These communities are usually highly diverse but interactions are mostly limited to the immediate neighbourhood of cells.

One of the most common interactions among microbes and in microbial communities is metabolite-mediated cooperation, whereby cells leak various products into their environment, which can diffuse over small distances. These molecules may serve as food for others or antibiotics, enzymes or signal molecules, that may mediate higher-order interactions between cells, ultimately facilitating or inhibiting the partner’s reproduction.

Metabolic interactions based on mutual assistance and cooperation – such as syntrophy, or cross-feeding – are widespread among microbes and are crucial for the formation, functioning and maintenance of these communities, probably also responsible for the unculturabiolity of many prokaryotes. However, products are usually costly to produce and can easily be diluted or are subject to exploitation by free-riders.

The most effective form of metabolic cooperation between different species is symbiosis, in particular endosymbiosis, where one cell physically relocates into the other. While this is an obvious way of stabilising the mutually beneficial relationships so common among microbes, only one such (presumed) case is known so far. Mitochondria, a crucal eukaryotic acquisition, have evolved to cellular organelles via endosymbiosis, when a bacterium moved into an archaeal host, about 2 billion years ago. Some theories suggest that this highly successful relationship emerged from an already existing mutually beneficial metabolic syntrophy between partners. However, no syntrophic relationship approximating endosymbiosis is known at all among any two modern prokaryotes (unicells lacking a nucleus). The emergence of eukaryotes from prokaryotic ancestors was a major evolutionary transition, during which cells lost their autonomy and created a new evolutionary unit responsible for the macroscopic living world around us. Although syntrophy is extremely widespread in the prokaryotic world, we know of no demonstrable case leading to a major transition, syntrophic, endosymbiotic or other. Why is it that prokaryotes are seemingly not able to “level up”? Why do we not see more major transitions in the prokaryotic domain? Why do we not see a transiton in individuality in microbial biofilms, as it has happened multiple times independently in case of eukaryotic multicellularity?

In their studies, the researchers of ÖK have categorised selection forces according to which ones facilitate and which ones hinder the establishment, reproduction and possible higher organisation of microbial communities. They have taken into account the community characteristics: species composition, coupled metabolism, metabolic functions, community building and interaction patterns. Some of these can be stably maintained in by certain microbial communities, and may also reappear when new communities are formed. If communities can also transmit minor changes, it is capable of informational inheritanceing. If bacterial colonies have such an adaptive property, it may be stably maintained in the population, for example in new colonies that bud off from the parent colony. If this trait provides a selective advantage to the colony, it should be maintained through higher level, e.g. group selection. This would be the first step towards a prokaryotic major transition. However, due to the high variability of bacterial communities (and their composition), the chances of this happening are low, and we do not yet see convincing examples.

An alternative solution, the researchers suggest, is for the loose interaction network to lead to tight pairwise symbiosis through higher levels of selection. A textbook example of this is endosymbiosis, the engulfment of a cell by another cell, which is common in eukaryotes but unknown in the prokaryotic world except for the origin of the mitochondrion. Prokaryotes seem to have been given the opportunity to move to a higher level of organisation only once. It is this fruitful relationship that has led us to read these lines.

Zachar, I. and Boza, G. (2022). The Evolution of Microbial Facilitation: Sociogenesis, Symbiogenesis, and Transition in Individuality. Front. Ecol. Evol. 10:798045. doi: 10.3389/fevo.2022.798045



The Ecology of Spider Sociality: A Spatial Model

Zsóka Vásárhelyi and István Scheuring, researchers at the Institute of Evolution, Centre for Ecological Research, and Leticia Avilés, a researcher at the University of British Columbia, studied the geographical distribution of spiders with varying levels of sociality by modelling the Eastern slopes of the Andes in a computer simulation. They have shown that the ecological characteristics of a given habitat fundamentally determine whether social or subsocial species live in that habitat. The study presenting the results was published in the journal American Naturalist.

Spiders are typically known as solitary and aggressive animals, yet there exists a handful of spider species in the tropics where closely related individuals live in a common web. They maintain their dense, three-dimensional web together, they subdue and consume their prey together, and they care for the offspring together. These species are called social spiders. Their study may contribute, among others, to a deeper understanding of the evolutionary and ecological background of social behaviour.

It was empirically observed that with increasing altitude and latitude social spider species are being replaced by less cooperative, subsocial species, which, although characterised by long maternal care, do not show extensive social behaviour. The question naturally arises, what factors shape these geographical species distributions.

In the corresponding literature two separate hypotheses were offered to explain this pattern. According to the Prey Size Hypothesis, a common web (and a social lifestyle) is only worth maintaining where a sufficient amount of large prey are available. Although the surface-volume ratio of the web decreases with the size of the colony, the size of the prey items, available only for cooperating collectives, can compensate for this effect.

In contrast, the Disturbance Hypothesis suggests that where the environment is strongly disturbed (by wind, rain, or predators), solitary individuals cannot reproduce stably. This is because the dense three-dimensional web, characteristic of these species, is very expensive to maintain. If the mother is unable to care for her offspring long enough, for example, because of the energy loss due to web maintenance, the offspring will die before maturing. Thus, the two hypotheses suggest that the distribution of social species is limited by the size of the prey and that of the subsocial species by the degree of disturbance.

The researchers in their latest study modelled the Eastern slopes of the Andes with a computer simulation, incorporating the respective environmental gradients (changes in the maximum size of prey animals and the degree of disturbance). They then placed several social and subsocial “virtual colonies” into this modelled habitat, and observed which species survived in which environment, with what success.

The model illustrates well that together the prey size and the level of disturbance can indeed re-generate the naturally occurring distribution patterns. The researchers have shown that high disturbance is not only responsible for destroying small colonies, but can also have a potentially stabilising effect, especially in the largest colonies. The results suggest that the ecological characteristics of a given habitat may have a significant impact on the social behaviour of the species living there.

Image: A social spider colony and some of its members (top right). The images show one of the species that inspired the study (Anelosimus eximius). The photo was taken by L. Aviles in Equador.



Spectral sensitivity transition in the compound eyes of a twilight-swarming mayfly and its visual ecological implications

Researchers of the ELKH Centre for Ecological Research, Institute of Aquatic Ecology and the Institute of Biology of Eötvös Loránd University (ELTE) studied the spectral sensitivity of mayflies during their larval and adult life stages. Using electroretinography, they showed that the visual system of the virgin mayfly (Ephoron virgo), a protected species in Hungary, adapts to changes in light conditions during development.
The study, which presents their results, was published in Proceedings of the Royal Society B.

Larvae of the virgin mayflies hatch from the eggs around April, they feed on organic material in the river bottom and develop until the swarming period, which takes place late summer. Swarming starts after sunset during twilight. The larvae float to the surface, where they emerge. The males undergo an additional moult, and after mating, the
fertilized females fly a few kilometres upstream above the river so that the eggs become laid into the water approximately at the same place where the previous generations developed.

The swarming of the virgin mayfly is restricted to a relatively short time frame during twilight, when the environment is almost completely dark for the human eye, but the scattered light of the sun still dominates the sky. At this time the content ratio of blue and ultraviolet photons compared to longer wavelength components is the
highest in the skylight.

In their most recent study, the researchers measured the spectral sensitivity of the compound eyes of larvae and adults of the virgin mayfly with electroretinography and found significant differences between these life stages. “The larval eyes were mostly sensitive to the green spectral range, while the eyes of the adults had a sensitivity
maximum in the ultraviolet” said Ádám Egri, research fellow at the Institute of Aquatic Ecology, the first author of the study.

The virgin mayfly develops underwater, where the short wavelength light is filtered out in the turbid water. This means that the green, yellow and red wavelengths are dominating this underwater world. Thus it is advantageous for the larvae to have eyes being primarily sensitive to the green spectral range.

Using webcams images, the researchers determined that the virgin mayfly typically swarms between solar elevations of 14 and 7 degrees below the horizon, when the content ratio of ultraviolet and green photons is the
highest in the skylight. Thus, the primarily ultraviolet-sensitive eyes of adults suggests adaptation to the light conditions of the twilight.

“We have previously shown that the virgin mayfly is mostly attracted to ultraviolet and blue light, which is in accordance with our new results” said György Kriska, associate professor at ELTE, who began to study the mass swarming and the streetlight-induced mass perishment of mayflies in 2012.

The mass perishment of the virgin mayfly at illuminated areas, e.g. bridges, is a well-known phenomenon, which can be reduced by the correct choice of the spectrum of outdoor lighting. Most short-wavelength light sources, such as the bluish cold-white LEDs, attract far more mayflies than the yellowish, warm-white LEDs which emit
light primarily in the longer-wavelength spectral range.

Thus, these results support the general agreement that long-wavelength artificial light cause the least ecological damage to the environment.

Photo: Imre Potyó



Eurasian crane (Grus grus) as ecosystem engineer in grasslands

Ecosystem engineer organisms alter the local environmental conditions and resource distribution in a way that they create and maintain habitats or microhabitats for other organisms. The engineered patches are characterised by different structure and functioning compared to the surrounding habitats. Well-known ecosystem engineers include corals that create reef habitats or beavers that literally engineer whole landscapes. Among birds, woodpeckers are well-known engineers that create nesting places for many other birds. In grasslands, the ecosystem engineering effect of birds has been largely unknown. Members of the CER IEB ‘Lendület’ Seed Ecology Research Group studied this interesting phenomenon and published their results recently in the journal Land Degradation and Development.

They studied a large, iconic bird species, the Eurasian crane (Grus grus) which is a protected species across Europe. The global crane population – thanks to the conservation efforts, wetland restoration projects and to the ability of cranes to coexist with intensive agricultural practices –shows a growing trend. Because of this population increase, it is possible that the effects of cranes on natural ecosystems will also amplify, that is why it is timely and important to evaluate the effects of this large bird on the grassland ecosystems.
Hungary is an important stopover area during the migration of cranes. During autumn, 100,000 – 160,000 birds spend a few weeks in the lowland areas of East-Hungary. Cranes are usually foraging on maize stubbles on crop residue, but regularly visit grasslands where they forage on invertebrates. In grasslands they perform a special feeding habit called ‘crane-ploughing’: they heavily disturb the soil surface with their bill and remove the vegetation. The disturbed surface resembles to a ploughed area and their size range from a few square metres to a few hectares. These are characteristic landmarks in Hungarian alkaline grasslands, but until this recently published study, their ecological function was unknown.

The researchers compared the vegetation of crane-disturbed patches and undisturbed alkaline grasslands in the Hortobágy National Park. They found that the disturbed surfaces were characterised by different structure and function compared to the undisturbed patches. The pioneer vegetation on the disturbed patches sprouted earlier than in the undisturbed grasslands, and was characterised by short-lived plant species and forbs. The crane-ploughed patches harboured more species and a different species composition compared to the undisturbed grasslands.

There were important trade-offs between the positive and negative effects of the foraging activity of cranes on different structural and functional components of the ecosystems. The abundance and species richness of insect-pollinated plants increased on the disturbed patches which suggests that these areas offer important nectar sources for pollinators in the otherwise grass-dominated habitat. The early sprouting vegetation on the disturbed patches probably provides important forage source for the livestock early in the season, but in the dry summer period the forage quality value decreases considerably.

The study showed that foraging cranes have a fundamental effect on the structure and functioning of alkaline grassland ecosystems, by creating patches with altered vegetation composition and ecosystem functioning. This impressive ecosystem engineering is the result of a few-week long foraging, and even though the disturbance is temporal, its effect may last for many years.

Valkó, O., Borza, S., Godó, L., Végvári, Z., Deák, B. (2022) Eurasian crane (Grus grus) as ecosystem engineer in grasslands ‒ conservation values, ecosystem services and disservices related to a large iconic bird species. Land Degradation and Development