The first pan-European study of its kind (Keith, H., Z. Kun, S. Hugh et al. 2024 – nature, communications earth & environment) calculated that Europe’s existing forests could sequester up to 309 megatons of carbon dioxide per year for 150 years if the use of these forests were abandoned and we let them continue to grow and re-grow.. This is equivalent to the CO2 reduction rate targeted in the European Green Deal for the LULUCF sector by 2030 (310 Mt/ha) and is greater than the current level of sequestration of managed forests in Europe (289 Mt/ha).
The authors calculated the amount of carbon stored in above-ground, below-ground and dead biomass from survey data on 288,262 trees in the remaining European primeval and old-growth forests in 27 countries, on 7,982 plots.
Surveyed primary and old-growth forest stands on Europe’s forest cover map
The carbon stocks and carbon sequestration capacities of naturally functioning primary and old-growth forest ecosystems composed of native trees are essential benchmarks. The authors calculated this benchmark forecological zones and forest types, ranging from low-productivity alpine birch forest in Sweden to the highest productivity mixed spruce-fir-beech forests in Bosnia-Herzegovina. Based on this, the predicted carbon carrying capacity of primary and old-growth forests is 22,449 MtC compared to 9,790 MtC in managed forests.
Aboveground carbon stock per hectare – Hungarian data are in the group of “Temperate continental forest – broadleaf” (case numbers are given in the columns)
The GlobBiomass and GeoCarbon projects have so far significantly underestimated forest carbon stocks in all forest types compared to data from primeval and old-growth forest.Therefore global models and parameters need to be developed and revised. Analysis of the tree density, diameter distribution and biomass of standing trees has shown that the thickest trees play the largest role in carbon storage, as half of all biomass is stored in trees thicker than 60 cm.
Tree density (light green) and carbon stock (dark green) of primary and old-growth forests by diameter class with the profile of cumulative biomass (red curve)
The protection and restoration of primary and old-growth forests are therefore not only of paramount importance for the conservation and maintenance of biodiversity, but also have an increasing role in mitigating climate change through their huge carbon sequestration and storage potential.
Researchers of the HUN-REN Centre for Ecological Research also contributed to the pan-European study with recent survey data of forest reserves representing the natural conditions of the Carpathian Basin.
The survey of forest reserves is supported by the public monitoring programme of HUN-REN Centre for Ecological Research and the Ministry of Agriculture.
Slide photo: Beech forest remnant in the Kékes Forest Reserve (Photo: Attila Bíró)
There is a lot of debate about how and why simple multicellularity emerged many times independently and what factors contributed to its prevalence. There are many theories why it was advantageous to be multicellular. Factors with direct advantage for aggregation (like avoiding predation) are evident but there are factors with indirect advantages, like spatiality and a changing environment. The latter can ensure the survival of the cooperative trait through group selection, without kin recognition or selection towards larger size (predation). Researchers of HUN-REN Centre for Ecological Research, Institute of Evolution and ELTE University investigated this hypothesis. They have modelled two types of cells in a temporally heterogenous, spatial environment. Cooperators can associate to form aggregates while cheaters cannot by themselves stick to others but can enjoy the benefits of the aggregate. In resource-rich environments, cooperators have a disadvantage due to slower growth, but only they can create propagules in resource-poor environments. Cheaters therefore need to piggyback propagule-forming cooperators to make it to the next rich habitat. The researchers have successfully demonstrated in their publication published in PLOS Computational Biology that cooperators can survive due to aggregation and group selection, enabled by spatiality in an alternating environment, without any further mechanism needed, like predation.
The evolution of multicellularity is one of the major transitions in evolution. It has occurred independently more than 25 times across different branches of life. Complex multicellular organisms, such as humans, achieve high complexity through related cells that remain together during division. In contrast, most single-celled organisms lack the regulatory mechanisms needed for this. For them, a simpler path is typically viable: forming multicellular structures temporarily, often under stressful conditions, like starvation. These aggregative multicellular species, such as the slime mold Dictyostelium, usually live as single-celled organisms. However, as their name suggests, the multicellular, slime-like form can move to a suitable habitat and grow a stalked fruiting body, which allows their spores to spread to nutrient-rich new locations.
The issue with this kind of multicellularity is that non-related individuals, or even those that don’t actively participate in cooperation (cheaters), can end up among the surviving cells. Since they don’t help, they can invest all their energy into feeding and reproduction—at the expense of the cooperative cells. This not only endangers the survival of the cooperative cells but ultimately the species itself, as too many cheaters would prevent the formation of the multicellular structure needed for reproduction. So, how can an aggregative multicellular species survive if cheaters always reproduce faster than cooperators? This is a particularly important question in the context of evolutionary transitions, where maintaining cooperation against cheaters is crucial.
Several hypotheses exist to explain why we see successful aggregative multicellular species nevertheless. One theory suggests that aggregation offers protection against predators: the more single cells stick together, the harder it is for a microbial predator to prey on them. Another hypothesis is that periodic starvation necessitates colonizing new habitats, which requires cooperative cells, thus even cheaters depend on them.
Researchers from the Institute of Evolution and ELTE University investigated these two hypotheses, examining the effects of aggregation and colonization under individual selection and group selection. They developed an individual-based, spatial computer model simulating the life cycle of a slime mold-like single-celled organism. In the model, cooperative cells produce the “glue” necessary for aggregation, while cheaters do not. The computer simulations clearly demonstrated that defense against predators is essential for the survival of cooperators in a continuously resource-rich environment. However, if resources periodically become scarce, predator-driven selection is not only insufficient but is also unnecessary for maintaining cooperation and multicellularity—it is a must to colonize new habitats.
Lifecycle of the slime mold Dictyostelium discoideum. (Source of insets: Wikimedia.) Single-celled slime molds usually start to aggregate when resources become scarce, and cells begin to starve. A secreted molecule (cAMP) coordinates movement to a tight aggregate that ultimately forms a slug. This motile form moves around to find a suitable spot for sporulation where it grows to a fruiting body with a stalk and spores in the head. Only the spores will survive to see the next habitat. The researchers have simplified this complex life cycle in their computer simulations, retaining only the crucial steps. Drawn by: István Zachar Photos: By Bruno in Columbus; by Usman Bashir (Copyright: CC BY-SA 4.0 Deed) and by Tyler Larsen (Copyright: CC BY-SA 4.0 Deed )
The researchers examined various colonization mechanisms (dispersal, fragmentation, aggregative spore formation, etc.) and found that only aggregative reproductive mechanisms can sustain cooperation long-term and robustly in such fluctuating environments. Thus, in a changing environment, group selection is more crucial than individual selection, in maintaining cooperation. The results suggest that these mechanisms played a key role in the evolutionary development of aggregative multicellularity.
In a nonchanging environment, predation, or any size-dependent selection, is enough to give a chance for cooperators to survive (top right). Without predation, however, cheaters will always win (top left). In a changing environment, when there is need to colonize new habitats, random dispersion decreases the chance of cooperators due to disrupting aggregations (middle). However, aggregation and aggregation-based colonization can effectively maintain cooperators against cheaters with or without predation (bottom left). Figure: István Zachar and István Oszoli
Dispersal is a crucial process in community ecology, through which individuals of a species can move into new and often different habitats. Species spread can happen actively, with individuals moving on their own, or passively, aided by dispersal agents. Understanding the dynamics and constraints of dispersal is a key to predict how species will adapt to changing environments, and can indirectly support biodiversity conservation and ecosystem stability.
The study of alien species dispersion is an important though relatively under-studied aspect of biological invasions. The colonisation of isolated wetlands and the introduction of pioneer and alien species are observable phenomena, but the underlying mechanisms are largely speculative. Researchers from the Institute of Aquatic Ecology at the HUN-REN Centre for Ecological Research have undertaken experiments on fish and plants to test hypotheses related to alien species dispersion. Previously, it was widely believed that waterbirds played an important role in the dispersal of fish in isolated water bodies, with fish eggs surviving passage through birds’ digestive tracts (i.e. endozoochory). Researchers at HUN-REN CER recently confirmed this hypothesis—the first such confirmation globally. However, questions persist regarding its prevalence among bony fishes and the variability in dispersal capacities across species.
In a series of feeding experiments with mallards, the researchers investigated the passive dispersal abilities of several common native (Wels Catfish, Common carp, Pike perch, Tench) and alien (Hybrid African catfish, Grass carp, Pumpkinseed, Amur sleeper, Stone moroko) fish species. In their paper, published in the journal Ecography, they reported the recovery of viable embryos of five fish taxa in the faeces of mallard, with successful hatching into larvae in one native (Tench) and one alien (Stone moroko) species. This result provide evidence that endozoochorous dispersal might be a widespread but likely rare phenomenon among bony fishes, with significant variability between species likely due to unique egg characteristics.
Herbivorous birds are known to play a significant role in seed dispersal, dietary studies from Europe showed that waterbirds can disperse hundreds of plant species, including many aliens. Moreover, passage through their digestive system can affect seeds’ germination rates. In a similar feeding experiment, researchers from HUN-REN CER compared the endozoochorous dispersal ability of six pairs of closely related (i.e. congeneric) alien and native wetland plant species. In their study, published in Freshwater Biology, they found that alien plant species can disperse more efficiently, with significantly higher seed passage rates.
However, these seeds germinated more slowly after gut passage compared to native species. Higher seed passage contributes to higher “propagule pressure” in new habitats, increasing the likelihood of establishing new populations of alien species. The delayed germination of aliens’ seeds also can offer a competitive edge to non-native species, particularly if they exhibit a fast growth rate and higher trait plasticity. Considering that mallards typically move several kilometres per day and even longer during migrations long-distance dispersal might be common and important for all studied plant species. Mallards also make shorter daily movements between wetlands, which might assist alien species to become fully established after their introduction to an area.
Pollinators are declining rapidly, largely due to land conversion and intensification of agriculture. To mitigate their crisis, low-disturbance habitats, such as sown wildflower plantings (commonly known forms are wildflower strips at the edges of arable fields), could promote pollinators by restoration of their resources (food, sheltering and nesting habitats). However, comprehensive knowledge is lacking on how landscape context, spatial configuration and age of wildflower plantings, seasonality and flower composition affect pollinator communities, especially from East-Central Europe.
To understand these effects, researchers from the HUN-REN Centre for Ecological Research established diverse native wildflower plantings within heterogeneous and homogeneous agricultural landscapes, by two spatial configurations: one large field or three smaller strips. Floral resources and wild pollinator insects (wild bees, hoverflies, butterflies) were sampled, in early and mid-summer, for two years after establishment (2020-21).
Flower resources of the sown plant species increased continuously, and were complemented at high rate by flowering plant species from the soil seed bank, especially in the first year. Both flower abundance and diversity increased the abundance of pollinators, highlighting the important role of using diverse seed mixtures. Wild bee abundance and species richness increased year by year and season by season, while butterfly abundance also demonstrated a yearly increase after establishment. Hoverfly abundance and species richness, however, showed an opposite trend, possibly due to the inter-annual variation. Wild bee and butterfly abundance was higher in the heterogeneous than in the homogeneous landscapes. Researchers did not observe any significant local effects of spatial configuration itself on pollinator populations.
Field-work photos from the transect walk method and the flower resources assessment from the four years of the study Photos: Borbála Bihaly (top left, buttom right) and Áron Bihaly (buttom left, middle and top right)
Our results emphasize that to support pollinators effectively, future wildflower plantings should be maintained for multiple years, in order to maximize floral diversity and ensure continuously available flower resources throughout the entire season.
Further results from the upcoming years and similar long-term and landscape-scale experimental studies are needed to understand all the benefits and ecological processes of diverse native wildflower plantings especially in understudied European regions.
The diverse floral resource of wildflower plantings in the second and third years and the pollinator insects visiting the flowers Photos: Viktor Szigeti (top left and middle left) and Borbála Bihaly (bottom row, top right and middle right)
Researchers at the HUN-REN Centre for Ecological Research (HUN-REN CER) are continuously studying the effects of changing environment on ecosystems, caused by human activity and climate change, and how animals respond to it. They recently showed that the increase of salinity of ponds can drive the evolution of planktonic organisms, and this process can be observed in the Daphnia (water flea) populations in the sodic water of World War II bomb craters in Hungary. The paper presenting their latest discoveries has been published in the flagship biological journal of the Royal Society, Proceedings of the Royal Society B.
Natural ecosystems are exposed to a multitude of stressors including climate change, urbanisation, or the rising salinity of aquatic habitats. These stressors change the environmental conditions, which determine the success of organisms. The emerging spatial variation in environmental factors is called a gradient. The Plankton Ecology Research Group at HUN-REN CER, led by research fellow Csaba Vad, studies the effects of environmental change on the functioning, species composition, and evolution of planktonic communities.
“Organisms have to adapt to environmental stress, otherwise they go extinct,” the researcher says. “Sensitive species can be replaced by other more stress-tolerant species, or the resident populations can also adapt to the changing environment. In other words, an evolutionary adaptation occurs in the population, and this provides an opportunity to survive in the habitat.”
Salinisation, the increasing salinity levels of aquatic ecosystems, is a global threat. The salinity of large lakes is rising as well, but the change can be much more dramatic in shallow temporary ponds. Salinisation is caused by many factors, but one of the most important drivers is increasing evaporation (as a result of warming). Meanwhile, pollution from mining or other industrial activities, or the environmental effects of urbanisation can also lead to salinisation.
Soda pan in the Seewinkel area, Austria (Oberer Stinkersee, photo: Horváth Zsófia)
Soda pans are naturally saline habitats in the lowlands of Carpathian Basin. The researchers studied the plankton communities and salinity of these soda pans and compared them to the communities of ~80-year-old sodic bomb crater ponds in the Great Plains of Hungary. Their exact origin is somewhat uncertain, but some sources suggest that during World War II, American bombers bombed the plains instead of the nearby airport, creating more than 100 explosion craters in an 800 m diameter circle. These craters were filled with sodic water and have since become very useful model systems for ecological research.
The salinity of the bomb crater ponds varies widely, so ecologists were able to compare their Daphnia populations and find out whether they are adapted to this environmental factor. Water fleas, such as the object of this study, Daphnia magna, are large-bodied zooplankton species, which are common model organisms in ecological and evolutionary research, because they play important roles in aquatic communities and can be kept easily in laboratories. “We wanted to find out whether the salinity tolerance of Daphnia originating from ponds with low and high salinity levels is different”, tells Csaba Vad. “We also studied soda pans, which are also sodic and hold similar zooplankton communities to the bomb craters. Both types of these habitats are naturally saline, and can be used as model systems, because their clusters consist of several ponds with different salinity levels in close proximity to each other.”
If local adaptation occurs, the salinity tolerance of the populations is matching with the salinity levels of their home ponds. This means that water fleas from more saline ponds will have a higher salinity tolerance compared to the Daphnia from less saline waters. In theory, local adaptation could be more prominent in more isolated habitats (in ponds more distant in space), because the mixing of their populations with others is less likely in the case of more distant habitats. The soda pans are kilometres apart, while bomb crater ponds are only a few metres away from each other. So, based on merely the position of ponds, more intense evolutionary patterns could be expected to be found in soda pans. But this was not the case.
Local adaptation (adaptation to the local salinity concentrations) was only found in the bomb crater ponds, which are very close to each other in space. There are some possible reasons underlying this observation. For example, salinity levels in soda pans are usually higher and more variable within and across years than in the bomb crater ponds. Soda pans are also shallower and larger, while bomb craters are deeper and smaller in diameter. When soda pans dry up, the resting eggs of water fleas can be easily blown to another pond by the wind. In contrast, bomb craters dry up more rarely (only in years with extreme weather conditions), their salinity level fluctuates less, and during the explosion, a prominent rim was created along their edges. Thus, Daphnia eggs cannot be as easily transported among the neighbouring ponds, and the more stable salinity levels allow for local adaptation to this stressor.
The researchers found adaptation to salinity in the soda pans as well, but this occurred on a regional level. Soda pans have a higher average salinity level than bomb craters, therefore the water flea populations from soda pans have higher overall salinity tolerance than those from the bomb crater ponds.
“Despite soda pans being more distant from each other, because of their more frequent drying-up, the gene flow among their Daphnia populations is more intense,” argues Csaba Vad. “Furthermore, many waterbirds visit soda pans, which transport several aquatic organisms from one pond to another. These circumstances overall reduce the possibility for local adaptation in this habitat type. In contrast, we found strong local adaptation in bomb crater ponds, which are sometimes only a few metres apart. Our results show that the response of aquatic communities to salinity may be influenced by several factors.”
Opening image: The model organism of the study, the water flea Daphnia magna Photo: Zsófia Horváth
Nowadays we hear a lot about climate change impacts in general, however, we still lack in-depth knowledge about how climate change might modify the processes determining the ecological status of lakes and the structure and functioning of aquatic communities. This is largely because these processes are intertwined in a complex manner, making any estimation regarding these changes challenging. In their latest study, researchers of the HUN-REN CER Institute of Aquatic Ecology used model simulations to analyse warming effects on phytoplankton dynamics based on field and experimental observations.
Although numerous lakes around the world have been showing an increase in annual mean temperature over the last few decades, it still remains difficult to assess long-term warming-related impacts in water bodies with various physical and chemical properties and diverse communities. Exploring these impacts is crucial not only for fishes, macroinvertebrates or aquatic macrophytes, but also for planktonic organisms, which form the basis of the aquatic food web and have a substantial influence on material cycles. Despite the broad range of sophisticated techniques developed to study this important group, elucidating how interrelated environmental factors drive plankton functioning is still a hard task due to the typically rapid dynamics of these communities. Monitoring based on regular field work is a crucial part of research on aquatic systems, but it is also time-consuming and lab-intensive, making any sampling effort limited in both space and time. In a sense, this is like following a streaming series with several seasons by only looking at a few snapshots from each episode, trying to guess what the actual story is.
We need complementary approaches to improve our ability to assess, estimate or forecast the ecological effects of climate change.Numerical models are promising candidates for this role, gradually gaining importance in ecological research. Generally speaking, such models describe fundamental relationships in the form of mathematical equations based on current data and scientific knowledge. Such relationships include e.g. species growth as a function of food item availability or the dependence of plant photosynthetic activity on light intensity. The strength of modelling lies in the possibility to create computer-generated simulations about changes in a population, community or ecosystem and their environment through space and/or time, helping to find causality behind natural phenomena. Thus, while field and experimental observations provide data about a series of temporary states and conditions, modelling aims at the processes that induce temporal change in those states and conditions.
In a Hungarian-Greek collaboration, Károly Pálffy, researcher of the institute’s Plankton Ecology Group, studied the dynamics of planktonic algae (phytoplankton, major primary producers of aquatic habitats) using an ecological modelling approach. While analysing a data series on Lake Balaton, Hungary in his previous study he found that the long-term rise in annual mean water temperature was accompanied by increasing seasonal fluctuations in phytoplankton composition (increasing seasonal variability), which might suggest a decline in ecosystem stability. He and his colleagues also managed to demonstrate something highly similar in a mesocosm experiment, raising the question of whether there is a more general connection between warming and the dynamics of planktonic algae.
A typical graphical output of a model simulation of one year run under different seasonal temperature scenarios (daily temperature values characteristic at present and increased with 1, 2 or 3˚C). Curves with different colours represent seasonal changes in the abundance of different species of algae. The modelling of temporal dynamics in multiple randomly assembled phytoplankton communities under different nutrient load and temperature combinations added up to more than 100,000 simulations. The study focussed on both short-term (one year) and long-term (30 years) changes and impacts.
The newly developed model made it possible to simulate changes in phytoplankton on the species level under various temperature scenarios. The output of the simulations was in agreement with the previous observations, elevated mean temperature caused more pronounced seasonal changes in phytoplankton composition, but the degree of this impact was also highly dependent on how the communities received inorganic nutrients essential for their growth. Accordingly, the ratio of the two most important ones, nitrogen and phosphorus as well as the temporal fluctuations in nutrient supply had significant influence on the effect of warming. This is in close agreement with recent studies that suggest the importance of considering nutrient load conditions (the so-called trophic state of a water body) when assessing the effect of climate change on aquatic ecosystems. Besides nutrients, initial species richness of the simulated communities also affected their response to warming. From a methodological point of view, this is an important finding, since it suggests that choosing an adequate number of species can be crucial in the planning of community-scale climate change experiments.
The recent paper published in Limnology and Oceanography also sheds light on what long-term consequences an increase in the seasonal variability of phytoplankton can have in terms of stability. At higher mean temperatures, seasonal extremes in community composition became more prominent, shifting the communities toward lower overall evenness. On a longer time scale, elevated temperatures also increased the probability of species loss, providing a mathematical explanation for the role of warming in reducing plankton community stability and thus modifying aquatic ecosystem functioning. The research group has plans for further extending the model, facilitating the simulation of climate change impacts in a spatial context as well as on the level of the planktonic food web.
Numerical models nowadays have an increasingly important role in the interpretation of field observations
The nature surrounding us, the living world, and the ecosystem provide us with the means to produce food. They play an essential role in regulating the climate by absorbing carbon dioxide, storing carbon, or protecting the soil from erosion. In recent decades, the concept of ecosystem services has gained ground. Its spread is due to the opportunity it offers to explore the complex interrelationships between the natural and socio-economic systems. It highlights how society and the economy are based on ecosystems and how human activities modify the natural environment. There is a clear link between the state of ecosystems and the well-being, health and happiness of people through ecosystem services.
Hungary’s current National Biodiversity Strategy to 2030 (3rd National Biodiversity Strategy) was adopted in August 2023. Its objectives are creating a coherent network of protected areas, improving the condition of different protected areas and restoring degraded ecosystems. The above objectives can only be achieved based on proper information and a thorough situation assessment. For this, we need a comprehensive understanding of the current state of our habitats.
Over the past five years, extensive cooperation has been established between sectoral experts and nearly 250 researchers and conservationists in a project coordinated by the Ministry of Agriculture (KEHOP-4.3.0.-VEKOP-15-2016-00001). One project element is the National Ecosystem Services Mapping and Assessment (MAES-HU), which aims to assess and map the extent of ecosystems, ecosystem condition and ecosystem services nationwide. The extensive collaboration resulted in several studies, which amounted to about 2,400 pages overall. The most important results are highlighted in a book titled ‘The Assessment and Mapping of Ecosystem services in Hungary’.
“One of the tasks was to assess ecosystem condition. However, what someone means by the condition of an area or habitat can be very varied,” says Eszter Tanács, one of the project researchers and a research fellow at the HUN-REN Ecological Research Centre. “Each stakeholder defines ‘good condition’ from their own perspective. They usually focus on factors that directly affect the state of the habitat or group of organisms that are especially important to them. For example, the health of plants (whether trees or crops of some kind) is an important indicator. If this is not in order, everyone pays attention. However, there may also be indirect links between condition and services that are more difficult to identify. For example, the diversity of wildlife in an area may be closely linked to its condition and thus indirectly to what services may be provided by the particular ecosystem type and in what quality.”
“To inform nationwide decisions, we need to produce maps that try to reflect the state of the environment and habitats nationally. This scale represents a particular challenge because the ‘goodness’ of large-scale maps depends to a large extent on the data we can base them on. However, how much detailed data we have for a given area is often arbitrary in space and time. Information on different types of habitat is not uniformly available. In the case of forests, where management means that we have to think in terms of decades or centuries, a lot of data are available at the national level. This is also true for agricultural land, partly due to the different subsidy schemes. For grasslands and wetlands, however, there is little information at the national level based on accurate measurements, although many sectors could make good use of such. Generally, more related information is available on very valuable protected areas, but these cover only a small part of the country’s territory,” said Eszter Tanács, explaining the difficulties of the task.
“Where there are insufficient sources of information, i.e. little measured data, the researchers have tried to indirectly estimate the extent of environmental pressures and mapped them. They have built on previous research and knowledge of responses to such pressures. Maps based on such relationships can also be used to estimate current condition and suitability for wildlife. Still, they have a relatively high degree of uncertainty because they represent risk. There are cases where only rough estimates can be provided through multi-step analyses – for example, flower abundance is estimated based on the presence of pollinators, and flower abundance is estimated based on what habitat is being discussed. The usefulness of such maps is more limited than those based on measured data. Therefore, an important element of our research is to investigate how well such maps reflect the condition according to more detailed, fine-scale data where they are available. This is a prerequisite for producing better and more accurate maps over time,” said Eszter Tanács.
The Ecosystem Map of Hungary, completed in 2019 (with a baseline year of 2015), was a major milestone in the implementation of the project. Although there were significant data gaps in some of the maps used for compiling it, a detailed, wall-to-wall land cover database has been developed. It is currently the best available for Hungary in terms of spatial and thematic resolution.
Proportion (%) of seminatural habitat types (based on the Ecosystem Map of Hungary) within a 300 m radius of each point
Researchers from the HUN-REN ÖK Lendület Ecosystem Services Research Group have reviewed European ecosystem services mapping projects using national experience in a recent prestigious international publication. The paper, published in the journal Ecosystem Services and first authored by Ágnes Vári, reviews the ecosystem mapping process in 13 European countries, presenting the results of a survey of project participants. The publication reviews the types of methods used, the ecosystem services assessed, the problems identified, and possible ways forward at the European level.
Publication:
Ágnes Vári, Cristian Mihai Adamescu, Mario Balzan, Kremena Gocheva, Martin Götzl, Karsten Grunewald, Miguel Inácio, Madli Linder, Grégory Obiang-Ndong, Paulo Pereira, Fernando Santos-Martin, Ina Sieber, Małgorzata Stępniewska, Eszter Tanács, Mette Termansen, Eric Tromeur, Davina Vačkářová, Bálint Czúcz: National mapping and assessment of ecosystem services projects in Europe – Participants’ experiences, state of the art and lessons learned Ecosystem Services, Vol.65, 2024, https://doi.org/10.1016/j.ecoser.2023.101592
Habitat fragmentation poses a growing global threat to our natural ecosystems, making it one of the greatest challenges in biodiversity conservation. Among the most vulnerable of these ecosystems are ponds, due to their small sizes and intricate networks. Ponds have experienced global declines in numbers and extent, making them a critical focus for conservation efforts. Once a pond loses its neighbors, it becomes isolated, which can lead to biodiversity decline. A new study, conducted in Hungary, sheds light on the importance of connectivity among ponds in these small-scaled habitat networks and its impact on the biodiversity of ponds.
Situated in the heart of the Pannonian Plain on the interfluve of the Danube and Tisza rivers, Hungary’s Kiskunság region is a diverse landscape, encompassing a variety of aquatic and terrestrial habitats. From shallow lakes, soda pans, and swamps to dry and wet meadows, semi-arid sand dunes, and grasslands, the region supports a unique array of flora and fauna, including numerous rare and endemic species. Large parts of the region belong to the Kiskunság National Park and are parts of a UNESCO Biosphere reserve, while a number of aquatic habitats are listed under the Ramsar Convention. Here, a cluster of 112 bomb crater ponds form a network with ponds differing in their distances, and therefore their relative connectivity to their neighbors. This so-called ‘pondscape’ was likely created during World War II by mistargeted bombing on a sodic meadow of the nearby airport.
Bomb craters may be scars on our Earth and reminders of devastating history but these ponds are thriving with life and providing habitat for a range of aquatic species today. They hold sodic water mostly dominated by sodium carbonates and hydrocarbonates and they vary in environmental and morphological characteristics. The ponds host a variety of species, including Pannonian endemic fairy shrimp (Chirocephalus carnuntanus), protected amphibians, pond turtles, and a range of invertebrates such as dragonflies, mayflies, aquatic beetles, and microcrustaceans. Beside its importance for conservation, the pondscape offers a unique setting for investigating scientific questions in a natural laboratory. The ponds are small and easy to sample and they form a well-delineated network far from other waterbodies. Therefore, they represent an excellent model system to understand how pond networks sustain biodiversity, and form a metacommunity, i.e., multiple separate habitat patches potentially connected through the dispersing organisms.
The ponds are not physically connected by waterways thus the dispersal of organisms is expected to occur mainly via wind or by the active movement of the organisms. The prevailing assumption has been that such small-scaled habitat networks lack structuring by spatial processes, i.e. we cannot observe diversity gradients in the network due to differential dispersal rates because all organisms could potentially spread to all habitats.
However, the findings of a study carried out by researchers from HUN-REN Centre for Ecological Research in Hungary challenge this notion. The researchteam investigated the influence of both space, i.e., the arrangement of the habitat patches and the local environmental variables (e.g. water nutrient content, depth, salinity) on species richness and community composition in an international collaboration led by Barbara Barta. These were tested in a range of organism groups including the tiniest microscopic creatures to ones as large as amphibians. They are expected to respond differently to the environmental conditions and connectivity.
“The findings showed that besides environmental conditions which certainly play a significant role in shaping community composition, the spatial position of ponds in the network is also important, particularly for passively dispersing organism groups. These are the organisms (e.g. microbes, plankton) that rely on dispersal agents, such as wind to move them across the landscape. For these species, it is better to be in the centre of the network where their pond is surrounded by many other ponds from which conspecifics can easily arrive. This leads to higher diversity of these groups in the centre of the pondscape.” explains Barbara Barta, the lead author of this study. This discovery highlights the importance of the central-peripheral connectivity gradient within pond networks.
“These findings underscore the significance of studying and conserving ponds as integral components of a network, rather than as isolated entities. It is crucial that the network as a whole is protected with all the connections which ensures that the biodiversity is sustained. Understanding the impact of connectivity on biodiversity in fragmented ecosystems like ponds is vital for the preservation of these unique habitats.” summarises Barbara Barta.
Photo: Horváth Zsófia
A network of bombcrater ponds on a meadow in Apaj, Central Hungary
One of the effects of climate change is shifting the habitats of species. For example, warming is pushing upward the forest boundary in high mountains. The question is whether the species’ speed of spreading is fast enough to follow the suitable habitats. Dr. Beáta Oborny, a researcher from the Institute of Evolution at the Centre for Ecological Research and the Institute of Biology at the Eötvös Loránd University, together with her colleagues have developed a new method to investigate this. Their paper co-authored with Dániel Zimmermann was the editor’s choice in Ecography. (The editor’s choice is a paper highlighted as the most exciting and novel paper in the monthly journal issue.)
As our planet undergoes significant transformations due to climate change, habitats are being altered, appearing, disappearing, or changing in quality. Understanding the impact of these changes on the geographic distributions of species is of great significance. The shrinking ranges of protected organisms and the expanding ranges of noxious species, such as pests and pathogens, highlight the urgent need to monitor range movements precisely. However, this task poses challenges as the available observation time is often short compared to the pace of underlying population processes, making it difficult to distinguish between directional shifts and random fluctuations.
Addressing this challenge, a research team led by Dr. Beáta Oborny from Loránd Eötvös University and the Centre for Ecological Research in Budapest has developed a novel method to monitor range shifts. The team aimed to precisely and consistently delineate range edges, allowing for comparisons between different years, geographic locations, and species.
Delineating range edges accurately is a non-trivial task as they often exhibit complex patterns. Occupied peninsulas are interspersed with unoccupied bays, and isolated occurrences dot the landscape. While traditional methods rely on the outermost occurrences of a species, Oborny and her colleagues propose a different approach. They suggest marking the range edge at the boundary between connected and fragmented occurrences, known as the “hull.” By marking the average position of the hull, the “connectivity limit,” over time, the researchers offer a statistically more reliable method. This region has a higher population density and exhibits smaller fluctuations, enhancing the robustness of the approach.
An upper limit of Dwarf mountain pine (Pinus mugo) in the low Tatra Mountains, Slovakia. The inset shows a snapshot from simulated population dynamics. Dark/light green shows the connected/fragmented occurrence of the species. The hull is marked by red. Photo: Courtesy of Konrád Lájer simulated image: Beáta Oborny
Oborny and her colleagues delved into the pattern-generating mechanisms using spatially explicit models. Unlike previous approaches based on general spatial statistical methods, their novel approach capitalizes on knowledge about the mechanisms governing the emergence of these patterns: birth, dispersal, and death within populations. Through computer simulations along environmental gradients (e.g., hillsides), the team explored the connectivity limits of different kinds of species. Remarkably, they discovered that the hull displayed a robust fractal structure with a dimension of 7/4. Further investigations conducted by Beáta Oborny and Dániel Zimmermann confirmed that this fractal structure remained consistent regardless of whether the range was rapidly advancing or retreating compared to the generation time. Notably, the method demonstrated particular robustness in the retreating (trailing) edge of species ranges. These findings highlight the applicability of the connectivity limit in tracking range shifts across diverse geographic scenarios, enabling a global perspective on these changes. For instance, the method allows for the comparison of treelines in different mountains, even when composed of different species, utilizing universal scaling laws.
The universal features uncovered in this study find their explanation in percolation theory, a field of research in statistical physics. This exemplifies the power of knowledge transfer between seemingly disparate scientific disciplines. The insights gained from these investigations deepen our understanding of the intricate relationship between environmental changes and species distributions. As scientists continue to refine and validate this method, it holds the potential to contribute to more robust assessments of biodiversity shifts and inform effective conservation strategies.
Image:An upper limit of Dwarf mountain pine (Pinus mugo) in the low Tatra Mountains, Slovakia. The inset shows a snapshot from simulated population dynamics. Dark/light green shows the connected/fragmented occurrence of the species. The hull is marked by red.
Photo: Courtesy of Konrád Lájer simulated image: Beáta Oborny
Our park ponds typically hold good numbers of mallards, and urban grassy areas often hold concentrations of geese. In the UK, Canada Geese are an abundant and widespread alien species, well known for fouling parks with their faeces. Until now, no attention had been paid to their role in seed dispersal, a major ecosystem service. Indeed, in the UK there has been surprisingly little attention paid to the role of wildfowl (ducks, geese and swans) in the spread of native or alien plants, a role of ever greater importance under climate change.
A new study from the Centre for Ecological Research in Hungary, in collaboration with the Doñana Biological Station in Spain, and the Wildfowl & Wetlands Trust and Liverpool John Moores University and University of Lincoln in the UK, compares the plants dispersed by mallards and Canada geese found together in 18 different urban and rural wetlands in north-west England (covering Merseyside, Greater Manchester, and the Lake District). In total 507 droppings were collected from the waterside, and examined for seeds and other plant propagules (i.e. dispersal units, that can include whole plants such as duckweeds) in the laboratory. Over 900 intact seeds were recovered, many of which were then germinated in the lab to prove they had survived gut passage.
“Although Darwin recognized the importance of migratory waterbirds in dispersing aquatic plants, this is the first detailed study of seed dispersal by ducks ever to be conducted in the UK, as well as the first European study to compare coexisting ducks and geese” said Andy J. Green, co-author of the paper. Over 33 plant species were identified, most of which were terrestrial plants, including trees and four alien species.
“We found that mallards and Canada geese have complementary roles” said Ádám Lovas-Kiss, senior author of the study. “Mallards disperse relatively more aquatic plants, and those with larger seeds, whereas Canada geese disperse more terrestrial plants”.
Both ducks and geese dispersed mainly plants that do not have a fleshy-fruit, and these have previously been assumed to have no or limited ability to disperse via animals, with no mechanism of moving more than a few metres. However, wildfowl provide perfect plant vectors, due to their long-distance flights, so they can help plants to reach new habitats, and to maintain connectivity between isolated plant populations, including different urban parks. For example, even wind-dispersed trees such as the Silver Birch, whose seeds were common in the faeces of both birds, will be dispersed much farther by wildfowl than by wind.
The study also found that the birds can continue to move seeds months after they have been produced on the plants, so for example migrating mallards can move seeds northwards in spring, which can help plants to adjust their distributions under climate change. Canada geese are relatively sedentary in the UK, although occasional movements of hundreds of km have been recorded. Alien plants were only recorded in wildfowl faeces in urban sites, but the study provides important evidence that they could also be spread from parks into natural habitats by wildfowl.
“We have been wrong to assume that only the 8% of European flowering plants with a fleshy-fruit are dispersed inside birds’ guts” says Lovas-Kiss. “Our study shows that many other plants are dispersed by birds, and that we need to pay much more attention to the role of ducks and geese as vectors of dispersal in urban ecology, as well as in natural ecosystems. Even alien geese can provide an important service by dispersing native plants”.
Biological invasion is considered to be one of the main drivers of biodiversity loss with potential negative socio-economic impacts. Invasive alien plant species are well adapted to rapid establishment and exploitation of the resources of disturbed environments, therefore disturbed and intensively managed habitats may support high levels of invasive species. Ecological restoration – defined by the Society for Ecological Restoration as the process of assisting the recovery of an ecosystem that has been degraded, damaged or destroyed – is increasingly recognized as a relevant tool to combat land degradation and biodiversity loss, and also invasive alien species. As the invasion problem becomes increasingly serious, there is an urgent need to develop more innovative, effective and proactive strategies to help improve the resistance of restored communities to invasion, limiting the establishment and further spread of invasive alien species.
In order to develop a prevention and mitigation strategy, it is necessary to understand the processes underlying biological invasion and resistance to invasion. The success of invasive alien species can be explained by the invasiveness of the species, the invisibility of the resident community and propagule pressure. The susceptibility of community to invasion, or its opposite, the ability of communities to resist invasion depends on the competitive ability of the resident community. Several factors can be responsible for the invasion resistance, such as the diversity or, more importantly, the functional diversity of resident communities, the presence of competitive dominant or rapidly developing native species that can exploit resources more fully or rapidly, limiting the potential for invaders to establish. Recently, functional similarity, propagule pressures and priority effects have become the focus of attention in attempts to explain resistance to invasion and to promote the restoration of invasion-resistant communities.
According to the limiting similarity hypothesis, species that use the same resources similarly cannot coexist stably, thus, in theory, integrating native species into restoration that are functionally more similar to known high-risk invasive alien species could lead to better resistance to invasion. High propagule pressure increases the chances of establishment, niche occupation and resource acquisition, therefore, density-driven suppression of invasive alien species is possible by increasing the seeding density of native species to match the propagule pressure of invasive alien species. Finally, priority of arrival has the advantage of early resource acquisition, which can strongly influence competition and survival, and thus ensuring the priority of native species; for example, by assisted dispersal, can be used to create communities that are more resistant to invasion.
The quantitative review of 48 papers indicate the potential of seed-based ecological restoration in controlling the establishment and growth of invasive alien species. Giving priority to native species was found to be the best approach in increasing invasion resistance that can reduce the performance of invasive alien species by more than 50%. Even a short-term advantage (as little as one week) can strongly favor native species, but the priority effect can be strengthened by increasing the time advantage. Seeding functionally similar species generally had a neutral effect on invasive alien species. High-density seeding is effective in controlling invasive alien species, but there can be thresholds above which further increases in seeding density may not result in increased invasion resistance.
Native perennial grass Festuca vaginata and invasive annual grass Tragus racemosus grown together in a greenhouse experiment studying the potential of limiting similarity, seeding density and priority effects to increase the competitive advantage of native species over invasive alien species.
Based on these results, the first step to prevent and mitigate the spread of invasive alien species is to create priority for the establishment of native species. This requires minimizing disturbance, reducing the propagule pressure and entry of invasive alien species, and introducing native species as soon as possible after disturbance. Native priority can be best increased by the early introduction of early-emerging, fast-growing native species and high-yielding communities. Seeding of a single species with high functional similarity to invasive alien species is unpromising, and instead, preference should be given to high-density multifunctional seed mixtures, possibly including native species favored by the priority effect. It is important to note that even combining the best methods to increase invasion resistance would not result in the complete elimination of invasive alien species, but would limit their biomass and seed production, reducing the risk of further invasion.
The study also highlights the need to integrate research across geographical regions, global invasive species and potential resistance mechanisms to improve the predictive capacity of invasion ecology and to identify best restoration practices to prevent and control invasive alien species.
Using a computer model, evolutionary biologists at the HUN-REN Centre for Ecological Research — including András Szilágyi, Tamás Czárán, and Mauro Santos, under the leadership of Eörs Szathmáry, a member of the Hungarian Academy of Sciences — have demonstrated that under the right circumstances, senescence can support the response to the directional selection and assist the adaptation to the changed environmental factors. The study’s findings were featured in a paper published in the journal BMC Biology. Senescence is therefore not necessarily an adverse by-product of natural selection but can also be advantageous for organisms. This represents major progress in explaining senescence, which remains one of the greatest unsolved problems in evolutionary biology.
The mystery of aging has fascinated people for millennia, with many willing to do anything to halt or reverse this process, because aging is typically associated with gradual deterioration of most body functions. While senescence is a natural part of life, biologists understand surprisingly little about the emergence of this process during evolution. It is not clear whether aging is inevitable, because there are organisms that seemingly do not age at all, moreover, the phenomenon known as negative aging, or rejuvenation, does exist: some turtles’ vital functions improve with age.
Researchers of the Institute of Evolution led by Academician Eörs Szathmáry have endeavoured to prove the validity of a previously proposed but still unproven theory of aging. The theory suggests that under the right circumstances, evolution can favour the proliferation of genes controlling senescence.
To test the hypothesis, the researchers used a computer model they had developed. This model is an algorithm capable of simulating long-term processes in populations of organisms and genes under circumstances controlled by the scientists. Essentially, with such models, evolutionary scenarios can be run, yielding results in a few hours rather than over millions of years. Modern evolutionary research would be inconceivable without computer modelling.
The fundamental question of the research was simple: Is there any meaning of aging? Does it serve any evolutionary function, or is it indeed a bitter and fatal by-product of life? “Aging can have an evolutionary function if there is a selection for senescence. In our research, we aimed to uncover this selection”, says Eörs Szathmáry. “According to classical explanations, aging emerges in the populations even without selection. That is because individuals would die sooner or later without aging as well (as a consequence of illness or accidents), therefore the force of natural selection in the population would get weaker and weaker. This creates an opportunity for the genes which have an adverse effect for chronologically old individuals (thus causing senescence) to accumulate. Which would mean aging is only a collateral consequence of evolution and has no adaptive function.”
During the last century, using different biological mechanisms, several evolutionary theories were formulated for the explanation of inevitable aging, which has no positive function. Several scientists accepted this assumption as fact, but when non-aging organisms were discovered, more and more researchers questioned the inevitability of senescence, and suggested perhaps aging could have some advantages as well.
“It has become accepted in the evolutionary biology community that the classical non-adaptive theories of aging cannot explain all the aging patterns of nature, which means the explanation of aging has become an open question once again”, says Szathmáry. “Alternative adaptive theories offer solutions for this problem by suggesting positive consequences of senescence. For example, it is possible that in a changing environment, aging and death are more advantageous for individuals, because this way the competition, which hampers the survival and reproduction of the more adaptable progeny with better gene compositions, can be decreased.”
However, this scenario holds true only if individuals are predominantly surrounded by their relatives. Otherwise, during sexual reproduction the non-aging individuals “steal” the better (that is better suited for changed environment) genes from the members of the aging population, and therefore the significant senescence disappears.
After running the model, the Hungarian biologists found that aging can indeed accelerate evolution. This is advantageous in a changing world because the faster adaptation can find the adequate traits more quickly, thereby supporting the survival and spread of descendent genes. This means that senescence can become a really advantageous characteristic and be favoured by natural selection.
Eörs Szathmáry 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 Great Steps of Evolution, co-authored with John Maynard Smith, is considered a cornerstone of modern evolutionary biology.
Diverse macrovegetation can provide heterogeneous habitats for benthic diatoms. Researchers from the CER Institute of Aquatic Ecology and the University of Debrecen, together with specialists from the Middle-Tisza Water Authority studied the importance of microhabitat heterogeneity (emergent, submerged and floating macrophytes) in maintaining diverse periphytic diatom assemblages. Their results were published in the journal Hydrobiologia.
Human well-being and good quality of life are based on the biodiversity of ecosystems and there is an increasing demand to reduce the knowledge gap on the variety of life on Earth. At the same time, an “invisible tragedy” is taking place in freshwater habitats that are highly threatened by the loss of diversity with species disappearing, threatening the functioning of the ecosystem. While relatively more information is available on the processes occurring in plant, animal or microbial communities that are important to human communities, much less is known about the vulnerability and exposure of other groups, including microalgae, which play a key role in ecosystem services. The situation is further complicated by the fact that there is a delicate balance between protecting and “exploiting” multipurpose freshwaters that take a lead in the daily life of human communities. While good ecological condition is essential for the maintenance of diverse communities, water management works such as water level regulation, thinning of macrophyte communities or sediment dredging are important for human recreation in these multipurpose lakes and reservoirs.
This is no different in the largest artificial, multipurpose shallow reservoir of the Carpathian basin, Lake Tisza, which is a UNESCO World Heritage Site. As in other lakes, the composition and biomass of the macrophyte communities form a complex system with benthic and metaphytic microflora assemblages. However, the extensive macrophyte vegetation needs to be thinned at least once a year. In the study, researchers highlighted that the macrovegetation belonging to different life form types, i.e. emergent, submerged and floating, contributes to the taxonomic and trait diversity of the microflora in a different but equally important way. Almost one-third of the benthic diatoms occurred on only one type of aquatic plant, pointing to the unique microhabitat that these macrophytes can provide for microalgae. Besides the microhabitats, however, the regular water level control of the lake also affected the biodiversity of the microalgae, promoting the spread of diatoms between the basins.
These results highlighted that the protection and maintenance of benthic microalgae biodiversity in multipurpose lakes requires delicate water management planning and implementation, but at the same time it is unavoidable for the functioning of a healthy ecosystem.
An international team of researchers has developed a new theoretical framework that bridges physics and biology to provide a unified approach for understanding how evolution and complexity emerge in nature. This new work on “Assembly Theory,” was published on October 4th in Nature.
As Dániel Czégel, the co-first author of the paper from Arizona State University and the Institute of Evolution at the Centre for Ecological Research in Budapest explained, “we have a language for physics, a language for chemistry, and a language for biology and evolution, but they are almost mutually incomprehensible, like as if we were at the early days of Babel. This makes the transition between them very difficult to study. We need something like a lingua franca of medieval port towns, to bridge cultures and languages. But these lingua francas often turn to fully developed languages, separate from their ancestors. Assembly theory is neither physics or chemistry or biology but a mathematical language to talk about historically contingent systems, systems where the existence of current forms are strongly determined by what existed in the past, like the products of biological or technological evolution. It turns out that a coordinate system for such complex objects are nothing like a coordinate system in physics, but it’s more like a space determined by combinatorics and recursivity. The most peculiar thing is that an object is not a point but a series of causes and effects, like a story of the origin of the object. And it’s not even the “real” history, but a fictional one, like an origin myth, but it’s mathematically well-defined within the assembly universe. It’s a counterfactual causal history. But then when we treat objects as their own fictional origin story, we can start to talk about the entangled web of stories of all objects and measure things like the amount of selection and historical contingency that caused those objects to exist. It’s a bit like the particle-wave duality of quantum physics, but for complex objects: sometimes it’s better to think of them as three dimensional structures, sometimes as interrelated construction histories. We have to speak the language of this coordinate system if we assume that life that we’d like to make in the lab or life elsewhere in the universe are not like ours, chemically.”
More than 50% of the world’s population currently lives in cities, yet cities can be home to significant biodiversity that provides important ecosystem services to urban populations. An international team of researchers, including Andrew J. Hamer, Senior Research Fellow at the Institute of Aquatic Ecology at the Centre for Ecological Research, has shown that urbanisation causes different changes in trait composition between animal groups through a systematic review of databases and publications on six terrestrial fauna groups (amphibians, bats, bees, birds, beetles and reptiles) in 379 cities on six continents. The study was published in Nature Communications.
Although urban environments cause significant habitat loss and alter the spatial structure of the landscape, it is crucial to conserve the remaining urban biodiversity and even increase the role of cities in reducing the current biodiversity extinction crisis. Understanding how different groups of animals respond through their functional traits to the impacts of urban environments worldwide is essential for developing effective strategies to promote biodiversity in urban environments.
Significant progress has been made in understanding the impacts of urbanisation on global biodiversity, there are still many gaps in research. Previous studies has focused geographically on major metropolitan areas in the northern hemisphere and Australia. However, the majority of the areas of greatest biodiversity value are in the tropics and the southern hemisphere, and these areas have been less investigated. Urban landscape structure has largely been characterised by negative indicators such as the proportion of impermeable surfaces, while biodiversity-enhancing indicators such as the proportion and spatial distribution of vegetation cover have received relatively less attention, particularly at the global level. Studies on urban biodiversity have so far mainly focused on plants and birds. Urbanisation also affects other species-rich and functionally important animal groups that have been little studied, such as insects, amphibians, bats and reptiles. Most studies on urban biodiversity continue to focus on taxonomic diversity, despite the growing importance of functional traits in the ecological literature.
In the Nature Communications study, six groups of terrestrial fauna (amphibians, bats, bees, birds, beetles and reptiles) from 379 cities on six continents were reviewed and shown that urbanisation causes taxon-specific changes in trait composition, with traits related to reproductive strategy showing the strongest response. The study results suggest that the impact of urbanisation on functional traits results in a set of four urban traits related to animal mobility and food preference, which can be classified into four types: mobile generalists, site specialists, central foragers and mobile specialists.
Mobile generalists includes taxa such as bats and carabid beetles are highly mobile species with more generalist diets and reproductive strategies that are better able to exploit available resources in urban environments. The urban trait syndrome associated with site specialists was characterised by reduced mobility, increased dietary specialism and a shift towards smaller clutch sizes. These traits are advantageous to species that are reliant on highly localised life cycles, such as amphibians and reptiles. Central place foragers establish a home base location from which they undertake daily movements to forage for additional resources. The taxa that displayed this urban trait syndrome were bees and birds. Mobile specialists are characterised by species that are able to meet their resource needs by being dietary specialists that are highly mobile and can move between spatially isolated food sources without having to return to a central place. Wetland birds can be regarded as mobile specialists, where their distribution is tightly linked to a specific resource (waterbodies), but they have the capacity to easily move between locations when resources fluctuate.
Frogs are site specialists – they are are reliant on highly localised life cycles (Photo: Shutterstock)
These findings are in contrast to the hypothesis that there is one single global ‘urban trait syndrome’ as a species response to urbanisation. The results therefore reassess previous ideas about ecological community dynamics and biotic homogenisation of urban ecosystems. It is crucial for the survival of different animal groups that conservation and urban development regulations and plans for cities and their environments take into account the different needs of different animal groups, as this may underpin the increasing role of cities in mitigating global biodiversity loss.
Lead photo: Julia Horanyi: An urban wetland that is habitat for species covered by all four urban trait syndromes
A new study that sheds light on the extraordinary sensitivity of freshwater ecosystems and the long-term negative consequences of human impacts on biodiversity has been published in the most prestigious scientific journal, Nature. The research is based on a comprehensive dataset of 1,816 time series of freshwater invertebrate communities between 1968 and 2020 from 22 European countries, comprising 714,698 individuals of 2,648 taxa from 26,668 samples. Two Hungarian researchers, Dr. Gábor Várbíró from the Institute of Aquatic Ecology of the ELKH Centre for Ecological Research (CER), and Dr. Zoltán Csabai from the University of Pécs (PTE) also took part in the compilation and analysis of the data. Due to the persistent and newly emerging threats posed by climate change, invasive species, and new pollutants, the study calls for an immediate and intensified focus on mitigation strategies to rejuvenate the recovery of freshwater biodiversity.
Freshwater ecosystems hold significant significance in the context of global biodiversity. These water bodies provide habitat for numerous plant and animal species, and they play a crucial role in maintaining food chains and preserving ecological balance. Mitigation measures including wastewater treatment and hydromorphological restoration have historically shown promise in improving environmental quality and supporting the recovery of freshwater biodiversity.
Together with a large international team the study’s first author, Prof. Dr. Peter Haase of the Senckenberg Research Institute and Natural History Museum in Frankfurt and Dr. Ellen A. R. Welti of the Smithsonian’s Conservation Ecology Center in the US analysed a comprehensive dataset of 1,816 time series of freshwater invertebrate communities between 1968 and 2020 from 22 European countries, comprising 714,698 individuals of 2,648 taxa from 26,668 samples. The analysis reveals a plateauing trend in the gains achieved.
714,698 observations of 2,648 species from 26,668 samples were analyzed by the research team. Dr. Gábor Várbíró, one of the Hungarian team members
The study indicates notable increases in taxon richness (0.73% per year), functional richness (2.4% per year), and abundance (1.17% per year) of freshwater organisms. These positive trends were prominent up until the 2010s, after which the recovery rates have significantly slowed down. Alarming patterns emerged in communities located downstream of dams, urban areas, and croplands, where the prospects for recovery appear grim. Moreover, sites experiencing higher rates of warming demonstrated fewer biodiversity gains, underlining the impact of climate change on freshwater ecosystems.
The study underscores the vulnerability of inland waters to a range of anthropogenic pressures, including pollution, urbanization, and the impacts of climate change. Despite past regulatory efforts, including landmark legislations like the ‘US Clean Water Act’ of 1972 and the EU Water Framework Directive of 2000, the researchers emphasize that more needs to be done to counteract the increasing stressors that threaten these vital ecosystems.
The researchers suggest that while the gains witnessed in the 1990s and 2000s could be attributed to successful water-quality enhancements and restoration endeavours, the observed deceleration in the 2010s suggests a diminishing effectiveness of the current measures. These measures led to a significant reduction in organic pollution and acidification, beginning around 1980. Over the past 50 years, these steps have contributed to the containment of wastewater pollution and resulted in improvements in freshwater biodiversity. Unfortunately, as the number and impact of stressors continue to increase worldwide, the improvements resulting from past legislation are lessening and freshwater systems remain degraded in many places. With the persistent and emerging threats posed by climate change, invasive species, and new pollutants, the study calls for an immediate and intensified focus on mitigation strategies to rejuvenate the recovery of freshwater biodiversity.
Biodiversity in river systems from 22 European countries increased significantly over a period from 1968 to 2020 – but this trend has stagnated since the 2010s
The involvement of two Hungarian scientists. Dr. Gábor Várbíró from CER and Dr. Zoltán Csabai from PTE adds a significant layer of expertise to this critical research effort. Their collaboration within the international team has shed light on the status of European freshwater biodiversity and underscored the urgent need for actionable conservation measures.
Dr. Gábor Várbíró said, “Our findings raise a critical alarm for the health of European freshwater ecosystems. The slowdown in recovery rates demands a comprehensive re-evaluation of existing mitigation measures and the implementation of new, adaptive strategies. Time is of the essence, and we must act swiftly to protect these essential ecosystems.”
The study underscores the necessity of a multi-faceted approach, engaging policymakers, scientists, and communities at large, to ensure the long-term vitality of freshwater ecosystems. As Europe and the world face increasingly complex environmental challenges, collaborative and immediate actions are crucial to reverse the trend of stagnating freshwater biodiversity recovery.
With the decisive participation of Eörs Szathmáry, Member of the HAS and Research Professor at the Institute of Evolution of the Centre for Ecological Research, an international team of researchers has achieved a major new breakthrough in the study of the origin of life. The paper was published in Nature Chemistry, one of the world’s leading chemistry journals.
Eörs Szathmáry Photo: HAS/Tamás Szigeti
The discipline of systems chemistry deals with the analysis and synthesis of various autocatalytic systems and is therefore closely related to the study of the origin of life, since it investigates systems that can be considered as a transition between chemical and biological evolution: more complex than simple molecules, but simpler than living cells.
Tibor Gánti described the theory of self-replicating microspheres as early as 1978. These still lacked genetic material, but concealed within their membranes an autocatalytic metabolic network of small molecules, isolated (compartmentalised) within their membranes. As the autocatalytic process takes place, the membrane-building material is also produced, leading to the division of the sphere. This system may appear to be a living cell, and although it lacks genetic material, this can only be verified experimentally. These microspheres can be considered as ‘infrabiological’ chemical systems, since they do not reach the level of biological organisation, but they exceed the complexity of normal chemical reactions.
Tibor Gánti / Painting by László Gulyás
Years ago, we started to think about the possibility of experimentally realising the process whereby the growth of a small molecule metabolic network leads to the growth of the compartments that enclose the network, to the effect that they can divide. Already Tibor Gánti has described that one of the most promising candidates for this system is the formose reaction, an autocatalytic sugar-producing reaction that consumes formaldehyde and involves the circular transformation and propagation of glycolaldehyde molecules. The reaction does not require enzymes.
The experiment on which the study is based was carried out in the biochemistry laboratory of the École Supérieure de Physique et de Chimie Industrielles (ESPCI) in Paris by Professor Andrew Griffiths and his colleagues. The experiment involved creating tiny water droplets in an oil medium that did not fuse and therefore acted as artificial cells. Some of the ‘cells’ were given glycolaldehyde as an autocatalyst (in addition to formaldehyde as a nutrient), others were not. In the former group, the formose reaction was triggered and, by osmosis, it sucked water away from compartments that did not contain glycolaldehyde. This allowed them to grow and to divide under external influence. Many researchers have suggested that before the emergence of regulated cell division, the initial cells divided in response to external influences such as turbulent flow.
The significance of this study is that we are the first in the world to show that the operation of a network of small-molecule autocatalytic reactions, without genetic material and enzymes, leads to the growth and division of compartments, i.e. the formation of new generations. This has never been demonstrated before, so the result is fundamental to the experimental verification of the principles of systems chemistry and points the way forward in the study of the origin of life.
Szathmáry Eörs evolúcióbiológus, az MTA rendes tagja, az MTA Fenntartható Fejlődés Elnöki Bizottság elnöke. Kutatásai során az élet keletkezésétől kezdve az emberi nyelvkészség kialakulásáig számos evolúciós folyamatot vizsgált és modellezett. John Maynard Smithszel közösen írt könyvét, az Az evolúció nagy lépéseit a modern evolúcióbiológia alapműveként tartják számon.
The researchers of the Functional Algology Research Group, operating at the Tisza Research Department of the Institute of Aquatic Ecology of the ELKH Centre for Ecological Research (CER), in collaboration with experts from the Department of Environment, Nature Protection and Waste Management of the Győr-Moson-Sopron County Government Office, investigated whether one-off drought events and trend-like precipitation decrease result in similar changes in the composition of diatom assemblages of the Rába River, one of the largest rivers in Hungary. The results clearly highlighted that the continuous decrease in annual precipitation has a much more significant impact on the composition and biodiversity than a single dry year. The paper presenting the research was published in the prestigious scientific journal Ecological Indicators.
Weather extremes and the impact of drought are immediately noticeable, for example, in agricultural areas or forests, and although perhaps less perceptible, they also have significant consequences for the ecosystems of rivers.
Reimeria sinuata: one of the diatom species indicating the effects of drought in the Rába River
The researchers of the Functional Algology Research Group, operating at the Tisza Research Department of the Institute of Aquatic Ecology of the ELKH Centre for Ecological Research (CER), in collaboration with experts from the Department of Environment, Nature Protection and Waste Management of the Győr-Moson-Sopron County Government Office, investigated the long-term changes in the composition of the benthic diatom assemblage of the Rába River.
The Rába is the third largest river in Hungary and the most important domestic tributary of the Danube. Over the past five years, environmental protection experts have observed a significant decrease in precipitation within its catchment area. They applied to CER researchers with the observation that the trend-like, continuous decrease in precipitation likely affects the composition of the benthic diatom assemblages.
During the joint work, they sought to find the answer to whether one-off drought events and trend-like precipitation decrease result in similar changes in the composition of the river’s benthic diatom assemblages. It has been shown in other ecosystems that the resilience of the assemblages can vary depending on whether drought occurs regularly, for extended periods, or only intermittently.
Maintaining the good condition of our rivers and reducing harmful effects, such as nutrient load, are important societal interests. The legal framework for this is determined by the EU Water Framework Directive, which Hungary also follows. In order to characterize and monitor the ecological status of our surface watercourses, experts regularly monitor the river ecosystems, in which benthic diatoms play a key role. These tiny organisms have a significant function in the food web and primary production.
Although microscopic in size, the biofilm they create is visible to the naked eye and can be felt, for example, on the steps of beaches, on rocks, and on shoreline and aquatic plants. Perhaps few people are aware of the wonders hidden within this film. When magnified, it reveals a micro-world resembling a small forest, where, similar to the ground level of a forest, there are species adhering on the surface, often very small, as well as prominent, branching species that resemble trees. Just as forests, the biofilm is also shaped by the environment. The number of species and individuals present, as well as the species with specific characteristics that can occur in a given biofilm, greatly depend on the influences affecting the water. Besides nutrient load, other threatening factors such as the increase in pharmaceutical residues, rising water temperature, changes in water residence time, drastic decrease in water level and flow, or the receding of flash floods significantly influence the composition of this tiny forest. Ultimately, this will also have an impact on higher taxonomic groups, such as aquatic invertebrates and fish,” said Viktória B-Béres, one of the lead authors of the study.
In order to understand these processes, the analysis and evaluation of long-term datasets are of paramount importance. For the investigation, the authors of the study utilized datasets available for the Rába River, covering a period of fifteen years. The period from 2007 to 2021 was divided into two groups based on annual precipitation. Between 2007 and 2016, fluctuating years of both drier and wetter conditions alternated, while from 2017 onwards, consistently decreasing annual precipitation was characteristic.
“Our results showed that one-off dry events had little influence on the composition and biological diversity of benthic diatom assemblages. In contrast, continuously decreasing precipitation ‒ dry periods ‒ significantly reduced species-level and functional diversities, the latter based on individual characteristics. Using the previous analogy, it was as if our tiny forest transformed into a barren landscape. Small-sized species that strongly adhere to the substrate, such as Amphora pediculus and Reimeria sinuata, became dominant, while the proportion of larger tree-like species decreased significantly. This is problematic because this type of algae plays an important role in the river’s food web as a food source for snails and macroinvertebrates. Therefore, their absence or decline in population size can have detrimental effects on the larger organisms inhabiting the river,” added Viktória B-Béres.
In a recently published study, researchers analyzed for the first time the differences in the effects between one-off dry weather events and trend-like changes in precipitation on the benthic diatom assemblages of a large river. The results clearly highlighted that the continuous decrease in annual precipitation has a much more significant impact on the composition and biodiversity than a single dry year. Climate scenarios project extreme water balance conditions in the near future, including longer periods of low precipitation. Therefore, any knowledge that can predict changes in the microscopic river ecosystems can assist in the development of action plans by authorities to preserve the functional and structural characteristics of riverine ecosystems, and thus maintain the ecosystem services provided by benthic algal assemblages. The study indirectly draws attention to the vulnerability of even large, perennial riverine ecosystems during dry periods, emphasizing the importance of responsible water management. The researchers are asking the public to report any incidents of extraordinary water pollution, untreated wastewater discharge, shoreline littering, or large amounts of mussel or fish carcasses to the environmental protection departments of e.g. the Győr-Moson-Sopron County or Hajdú-Bihar County Government Offices.
The members of the ‘Lendület’ Seed Ecology Research Group of the ELKH Centre for Ecological Research (CER) examined the human factors behind animal-vehicle collisions through a questionnaire survey. The researchers pointed out that there are significant correlations between the frequency of collisions, driver attitudes, and driving habits. The paper presenting the results was published in the Journal of Environmental Management.
The rapidly developing road network places a significant burden on terrestrial ecosystems, increasing the number and severity of conflicts between humans and wildlife, which are most often manifested in animal-vehicle collisions. Collisions with animals raise serious problems from both a conservation and traffic safety perspective. If we want to express this in numbers, it can be said that hundreds of millions of vertebrate animals are victims of vehicle collisions worldwide every year. This results in significant financial damage and personal injury. The problem is not new, researchers have been aware of it for decades, and numerous studies have been conducted. Most of these were based on field surveys. With their help, a list of affected species was compiled, conservation damage estimated, and “hotspots” identified, i.e., road sections where the frequency of collisions is higher than average.
“Our research is novel in that it targets the social strata traveling on the road, so it captures the problem from the other end. The experience and opinions of drivers contain a lot of useful information for accident prevention, which can be collected and evaluated in this way,” explained Sándor Borza, one of the first authors of the article, a PhD student in the Cooperative Doctoral Program.
It is very important to consider how interested the affected social stratum is in the topic, how conservation or financial damage affects them, and what solutions they consider good or acceptable to reduce the problem.
“Many people were interested in the survey, a total of 2123 people completed our questionnaire, which is an outstanding number worldwide!” emphasized Sándor Borza. “We were curious about what animals drivers had hit during their lifetime, whether they had suffered financial damage, and, most importantly, whether their driving habits and attitudes affected the likelihood of collision.”
The researchers found that nearly half of drivers have had at least one collision with an animal during their lifetime and one in four drivers suffered property damage as a result. Male drivers, drivers who cover longer distances annually, use secondary roads more frequently, and drive larger vehicles were more likely to collide with animals. However, driving style, whether someone drives slower or more dynamically, did not affect the likelihood of an animal-vehicle collision. “This does not mean that the two things are not related at all, as research supports that at certain speeds, it is not possible to slow down enough to avoid a collision,” added Sándor Borza. The drivers’ attitude towards the importance of nature conservation and traffic safety in relation to animal-vehicle collisions was significantly influenced by whether they had hit something before in their lives. More than a third of drivers shared their opinions on possible ways to improve traffic safety. The most popular form of action was the installation of protective devices (wildlife fences, wildlife crossings), but many also pointed out the usefulness of warning signs and the greater responsibility of hunting associations, including control of the number of large game animals.
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.
