Alkaline soda pans of Hungary are special representatives of inland saline waters in the interior of the continents. The largest number of soda pans in Eurasia is found in the Carpathian Basin, and these lakes are also important resting and feeding areas for migratory birds in the European-African bird migration routes. Evidence is mounting that globally, aquatic habitats and waterbird populations are being rapidly declined by the land-use and land cover changes of recent decades (drainage, run-off), and climate change: rising temperatures and changing rainfall patterns. Waterbird populations play an important role in trophic- and host-parasite networks, and their cultural and recreational role is also important, but as bird populations and habitats decline, these ecological services are also declining.

Emil Boros, Senior Research Fellow at the Centre for Ecological Research, Institute of Aquatic Ecology, has been studying the interaction between waterbird populations and soda pans for many years. In an earlier publication in the Science of the Total Environment they found that waterbirds contribute high phosphorus loading (P) to the shallow saline lakes through their droppings, i.e. birds act as vectors of external phosphorus sources, a process called guanotrophication (bird-induced nutrient enrichment). Waterbirds, such as large-bodied herbivores (goose and duck species) and medium-bodied omnivores (e.g. gulls) have been shown to be 64% responsible for the extremely high phosphorus content of natural soda pans. However, it was also found that, the hypertrophic state of water was in contradiction with the limited primary production of natural soda pans due to the characteristics of the lakes: shallow water depth, high alkalinity (PH ≥ 9), and intermittent hydrological cycle.

In a further investigation about the interaction between inland saline aquatic ecosystems and waterbirds the aim was to show whether the ecological/trophic attributes of saline water bodies could be predicted on multi spatial-scales by different groups (guilds) of waterbirds. Also published in the prestigious journal Science of the Total Environment, Emil Boros and colleagues studied a vast area of 1700 km by 1000 km at different spatial scales in the steppe and semi-desert region of Kazakhstan, where 63 sample area were selected. Nearly 100 waterbird species occurred in the sample areas and were classified into three groups according to their role in nutrient cycling and nutrient turnover: net-importers (large herbivores e.g. geese, cranes), importer-exporters (omnivorous ducks and gulls) and net-exporters (various herbi-, omni- and piscivorous species), based on Boros’s classification method. The abundance, biomass and diversity of these bird groups (guilds) were compared with the attributes of the inland waters on multi spatial scales e.g. water depth, chlorophyll content, and at larger spatial scales, with the land cover data found in the 1 and 10 km radius around the ponds e.g. grassland or agricultural land.

Their results showed that the occurrence of the above waterbird groups was strongly correlated with the attributes of the saline aquatic ecosystems on multi-spatial scale. Water cover and salinity are the main attributes predicting of the type of bird group that occurs in a given environment. The importer-exporter and net exporter bird groups showed positive correlations with productivity metrics and water depth of the waters, while the importers were predicted by the surrounding pond environment e.g. grassland.
The practical significance of this study is that it quantifies this ecosystem services provided by waterbirds, their role in nutrient cycling, which is essential for systematic monitoring and habitat management. The classification system and methodology described in this study can be used to estimate certain environmental attributes of inland water bodies for large geographic regions by counting waterbird populations. In the future, this will provide an opportunity to use birds to estimate ecosystem function and services of aquatic systems, which in turn will require further methodological studies.

Publications:

Emil Boros, Zarina Inelova, Zsuzsanna Lánczos, Zsolt Végvári: Waterbird guilds predict environmental attributes of inland saline aquatic ecosystems on multi-spatial scales,
Science of the Total Environment, Volume 855, 2023.
https://doi.org/10.1016/j.scitotenv.2022.158845.
https://www.sciencedirect.com/science/article/pii/S0048969722059447

Emil Boros, Anita Takács, Péter Dobosy, Lajos Vörös: Extreme guanotrophication by phosphorus in contradiction with the productivity of alkaline soda pan ecosystems,
Science of the Total Environment, Volume 793, 2021.
https://doi.org/10.1016/j.scitotenv.2021.148300.
https://www.sciencedirect.com/science/article/pii/S0048969721033714

Photos: Emil Boros – Red-necked Phalarope and Lake Balkas

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

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

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

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

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

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

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

The members of the ‘Lendület’ Seed Ecology Research Group of the Centre of Ecological Research followed the vegetation dynamics of artificially created grassland patches for several years. The researchers found that in the course of grassland-restoration the efforts at the beginning pay off: the simultaneous sowing of grasses and forbs in fallow lands leads to the development of species-rich grassland communities and efficient weed control.
The aim of ecological restoration is to recreate something lost or deteriorated. Grassland restoration aims to recreate grassland ecosystems and communities. In many cases recreation of the original ecosystem is not a possibility, but restoration still can help to cover landscape scars created by human activities. Restored grasslands not only improve landscape aesthetics but offer many different ecosystem services as well (e.g., forage for the livestock, nectar for pollinators, effective carbon capture and storage, and soil erosion control).
When grassland restoration is done with seed sowing, the success of restoration depends on many factors, such as the identity of sown species, the timing of sowing, the quantity, quality and proportion of sown seeds. In the current study the researchers aimed to find the best timing to sow grasses and forbs to achieve the highest possible species richness, to enhance forb-establishment and to hamper weed encroachment.
„The matrix of the grasslands is composed by grasses. Previous works found that sowing grass seeds certainly results in a closed grass sward within a few years, and also hampers weed encroachment. That is why grass sowing is preferred in landscape-scale restoration works. But it also has its feedbacks: the new grassland will be species-poor, as the closed grass sward hampers the establishment of other grassland species.” – explained Réka Kiss, the first author of the manuscript published in the Nature- Scientific Reports.
To create species-rich grasslands the use of diverse forb seed mixtures is needed. However, the compilation or production of such seed mixtures requires more efforts (seeds of more species are needed in good quality and high quantity). Due to these reasons diverse seed mixture is less likely to be used in the early stages of restoration. In later stages, however, it will need more effort from the practitioners to secure the successful establishment of species.
„We were curious of the most suitable timing: If we want to sow both grasses and forbs in a fallow for a species rich grassland, which is the time-lag when with the least effort we can achieve the most?” – explained Réka Kiss – „At the beginning of the experiment we created 36 patches in a recently abandoned land. We sow exclusively grass seeds, exclusively diverse forb seed mixture (20 species) or both of them into the patches. When we combined the grass with the forb seed mixture we sown them simultaneously (at the same time), or the diverse seed mixture was sown with a delay of 1, 2 or 3 years.”
Following the development of the patches for several years the researchers found that the best results were achieved when seeds were sown simultaneously, without time-lag. In such patches the species richness of species was the highest, the weeds were less successful and the establishment success of sown forb species was the highest. This is the most cost-effective and most successful method among the studied sowing regimes. If simultaneous sowing is not a possibility, sowing forbs one year later than grasses is still effective. However, after one year the advantage received by grasses cannot be outcome by the forbs, their successful establishment in later stages can be promoted only by active interventions.

Source: nature.com - Co-seeding grasses and forbs supports restoration of species-rich grasslands and improves weed control in ex-arable land - 2022-12-08

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

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

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

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

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

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

Fig 2: Average conservation priority of European countries.

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

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

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

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

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

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

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

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

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

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

Source: elkh.org

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