Visit to Denmark and search for ancient burial mounds

In the past week, we had the pleasure to visit Prof. Gábor Lövei at the Fjakkebjerg Institute of Agroecology, Aarhus University, Denmark. The primary aim of our trip was a visit to the state-of-the-art experimental greenhouse system of the institute to get inspiration on how to build ours in the future. Thanks to Gábor, we also had the opportunity to visit many ancient burial mounds and several other wonderful places. The structure and ecological function of the ancient burial mounds in Denmark are very similar to the 'kurgans' in many parts in Eurasia. It was impressive to see mounds very similar to our beloved kurgans in a different climatic and geographic context. Inspired by this field trip our research group is planning a cooperation with scientists in Denmark to study the biodiversity potential of the mounds in the intensively used agricultural landscape.

Many thanks to Gábor and Éva for their kind hospitality, we had a wonderful time! We hope that we can return to this nice country to study the biodiversity related to the ancient burial mounds :)

Below we selected some pictures to illustrate the highlights of our trip.

Typical ancient burial mound in the Møn island. A total of 8000 ancient burial mounds have remained intact in Denmark.

The entrance of the chamber remained intact or has been restored in many mounds. Also, in many cases, it is possible to go inside the chamber.

The entrance seems very narrow from outside, but inside, the chamber is quite spacious.

The inside part of the chamber.

A spider living in the chamber.

The chamber was built from megaliths, and the space between the megaliths was filled by smaller carved stones.

Large megaliths are often visible on the top of the mounds. Besides steep slopes, these large stones also protected the mounds from ploughing.

In a few cases, the mounds were surrounded by large stones.

Beautifully reconstructed stone age mound, surrounded by large stones on Møn island.

Grassland habitat island in the agricultural landscape.

Woody encroachment on the mounds is a typical phenomenon.

This was one of the mounds with the steepest slopes. Interestingly - similar to Hungary - the mounds in Denmark often have cultural importance also in modern times. The last public execution in Denmark took place on this mound.

Mound with moderate woody encroachment, which still holds landscape values.

On unmanaged mounds, litter accumulation and the encroachment of competitor grasses (in this case Calamagrostis epigeios) is typical.

Cultural diversity: on the left, an ancient burial mound; on the right, a medieval church on Møn island.

We also visited ancient viking sites, including the Trelleborg fortress.

Within the tall earthen rampart, houses were arranges in a regular order towards the four main directions.

Reconstructed viking 'long house' in Trelleborg - archaeologists used ancient materials and technology for the reconstruction of the buildings.

Long house in Trelleborg.

Mosses on the roof.

We also visited the wonderful white cliffs of Møns Klint.

Møns Klint.

It was very nice to see this nature-close beech forest at such a low altitude.

Early spring in the beech forest.

View to the white cliffs and the Baltic sea.

Wonderful seashore in the western part of Zealand.

Common kestrel (Falco tinnunculus) on the seashore.

Thousands of Barnacle geese (Branta leucopsis).

Whooper swans (Cygnus cygnus).

Foraging Barnacle geese.

Some disagreement among Black-headed gulls (Larus ridibundus).

Drying Great cormorant (Phalacrocorax carbo).

Common eider (Somateria mollissima).

Red-breasted mergansers (Mergus serrator).

And a few more pictures about the beauties of Denmark :)

The Cristiansborg in Copenhagen.

One of the millions of Danish bikes :)

A fountain with cranes in the old town of Copenhagen.

The colorful houses in the famous Nyhavn canal.

Guards at the Amalienborg palace.

Military band.

HRH Mary Crownprincess of Denmark, on her birthday at the Amalienborg palace.

The Amalienborg palace.

The famous Little Mermaide statue.

The Rosenborg palace.

Beautiful medieval church on Møn island.

Ship model in a medieval church.

Fortress cathedral in Kalundborg.

This 15th century house is one of the oldest preserved residential buildings in North-Europe.

This orange globe was made from recycled plastic and is being displayed in Copenhagen. On the background you can see the Opera House.

Picturesque old town of Dragør.

The harbour of Dragør, with the bridge to Malmö, Sweden in the background.

Harbour of Dragør.

Dragør seashore.

The cathedral of Roskilde is the burial place of the Danish royal family.

Roskilde was the ancient viking capital city. At the viking ship museum they reconstruct the ships using the ancient materials and tools.

Many a little makes a mickle: Global review about the importance of rodents and lagomorphs in seed dispersal

Our review paper by Laura Godó has recently been published in GECCO.

Godó, L., Valkó, O., Borza, S., Deák, B. (2022): A global review on the role of small rodents and lagomorphs (clade Glires) in seed dispersal and plant establishment. Global Ecology and Conservation 33: e01982. doi: 10.1016/j.gecco.2021.e01982 [IF2020: 3.380] 

The paper is open access, and can be freely downloaded from here.

This is a comprehensive review based on approximately 600 papers where we evaluated the role of small herbivores of the orders Rodentia and Lagomorpha in seed dispersal. The studied animal taxa occur in all continents, in all terrestrial habitat types, they form a diverse group with more than 2100 species. Practically these animals occur wherever seeds are present, so all seeds are eaten, dispersed or ignored by a small herbivore. Despite these, there are many knowledge gaps regarding the role of Glires in seed dispersal and many potentially important mechanisms have not been studied yet.

 

Examples of the most important small seed disperser mammals.

In our review we discuss the types of rodent- and lagomorph-mediated seed dispersal, with a special emphasis on epizoochory (dispersal on fur), endozoochory (dispersal  through the digestive tract), synzoochory (dispersal through food caches) and caliochory (dispersal through nest material). Then we evaluate the environmental factors and biotic interactions, such as soil properties, habitat structure, predation risk, that mediate seed dispersal by Glires. We also give an overview on the often human-induced threat factors that affect these seed dispersal processes, such as habitat loss and fragmentation, defaunation, invasive alien species. We higlight the peculiarities of Glires-mediated seed dispersal compared to dispersal by large herbivores and show examples on plant adaptations that influence Glires-mediated seed dispersal. Finally, we evaluate these plant-animal relationships from the perspective of ecosystem services and disservices and identify the major knowledge gaps and promising future research avenues. 

Finally, this article turned to be a very comprehensive, and hopefully very interesting review paper and congratulations to Laura for her hard work during the reading, writing and review process!

Abstract

Zoochory is an ecologically and evolutionarily important seed dispersal type. The decline and extinction of seed-dispersing large herbivores severely threatens dispersal-driven ecosystem processes in many regions. Hence the relative importance of small rodents and lagomorphs (Glires, Mammalia) as dispersal vectors might increase due to their ubiquity, diversity and abundance. Here we provide a review of rodent- and lagomorph-mediated seed dispersal based on approximately 600 papers found in an extensive literature search. We highlight that small rodents and lagomorphs disperse seeds via various mechanisms. The seldom documented epi- and endozoochory are probably universal in these groups. Due to their small home range, short fur and small body size, these mechanisms generally operate at small scales and mainly for small seeds. Taxon-specific feeding, nesting and behavioural characteristics provide a wide spectrum of other seed dispersal types, such as synzoochory (food caching). The studied taxa generally support seed dispersal within a particular habitat patch, contributing to the persistence of local populations, but in rare cases, long-distance dispersal events might occur. Besides seed dispersal, rodents and lagomorphs can also support plant establishment and provide safe sites for seeds where they can survive stochastic events. Studies reviewed here show a strong bias both in scope and geographical distribution: synzoochorous dispersal of woody plants is known in detail, and most studies were conducted in the same few countries and habitat types. In contrast, other mechanisms such as endozoochory, epizoochory and habitat types like grasslands and anthropogenic habitats have rarely been studied. We show examples on ecosystem services and disservices related to rodent- and lagomorph-mediated seed dispersal as well as the importance of these processes in habitat conservation and restoration.

New projects targeting public outreach and dissemination

 

Four projects from our research group received funding in the 'Scientific Mecenatura' call of the National Research, Development and Innovation Office. The call targets to support public outreach and dissemination activities and citizen science projects.

We are very happy that thanks to this funding, we will be able to continue and upscale our project that aims to support the use of native flowering plant species in home gardens instead of non-native, potentially invasive alternatives.

NKFI MEC_N 140750  Nature at home: Supporting native plant species in urban gardens

The mission of our project is environmental education by dissemination of knowledge, the practical involvement of participants and the analysis of social attitudes. Our project aims to bring nature closer to people, as a number of new researches prove that a greener environment contributes to maintaining our physical and mental health. It is also becoming more and more fashionable to decorate homes and courtyards of institutions with plants and flowers. We want to reach people through this ’fashion’ and offer a nature-friendly alternative, that is, we can also decorate our environment with native plants. Our project offers a good challenge or a playful task for almost all people with any area of interest, regardless of age, or even a new hobby. We offer the seeds of native flowering plants from which people can choose and plant them at home. This way the participants can get one step closer to a nature-friendly home, kindergarten or school yard. Our target group is wide, anyone from the preschool age can get involved and do something for nature conservation with their own hands. We create information and display materials which will be available online and in print. We create a website with useful functions and a short film which will be available on the YouTube video sharing website. We also create a promotional and news-sharing page on the Facebook social media website. Project participants receive a printed brochure containing all the necessary information. We provide the opportunity for personal meeting and contact; we also present our project in stands at nature- and environmental conservation events and in ‘green tents’ of festivals. An attention-grabbing molino is made for these events. We present our project in environmental and biology classes in primary and secondary schools. We ask the participants to fill in an anonymous questionnaire and ask for feedback on the results of the planting and the experiences. With the help of the questionnaire and the feedback, we can improve our project in the future, as it can shed light on the social attitude and on the criteria for choosing an ‘ornamental plant’. Our project is a good opportunity to combine an increasingly popular hobby, gardening, with nature conservation. It provides an opportunity for enthusiastic participants to collaborate, build a community, share experiences and support each other. For children – one of our main target groups – it can even serve as a school task to create a small garden at home or in the school yard and to follow and observe the development of the plants.

Our goal is to spread the word about the use of native flowering plants instead of non-native and potentially invasive alternatives in home gardens.

The project participants: Laura Godó (the main coordinator of the project), Orsolya Valkó (principal investigator), and we receive a lot of help from project participants: Katalin Lukács, Réka Kiss, Sándor Borza, Balázs Deák.

We will regularly give project updates here and elsewhere in the future :)

Besides this big project, three members of our research group also received funding for the communication of their results and presentation at international conferences:

Sándor Borza, MEC_R_141154: The common crane (Grus grus), an ecosystem engineer in dry grasslands

Soil disturbance by the common crane (the so-called 'crane-ploughing') creates distinct vegetation patches in alkaline grasslands.

Laura Godó, MEC_R_141151: Secondary seed dispersal by the Barn Owl (Tyto alba) in open habitats

Via diploendozoochory, a bird of prey, such as the Barn Owl can also contribute to the dispersal of plant propagules.

 

Katalin Lukács, MEC_R_141156: The role of humans in seed dispersal

During outdoor activities, we can unintendedly disperse a large amount of plant propagules on our clothes and footwear.

Book about the biodiversity preserved by kurgans

In the past years I have published two books (one in English and one in Hungarian) about the natural and cultural values associated with ancient burial mounds (kurgans). From the Hungarian book approximately 800 free books were provided to conservation agencies, farmers, researchers, schools and universities. In order to spread the word about the importance of kurgan protection to everyone interested, I decided to make the electronic version of both books freely available to everyone interested. The pdfs of the two books and some other related publications can be downloaded using this link: 

https://deakvalko.blogspot.com/p/kurgan-publications.html

Extinction debt in grassland islands embedded in agricultural landscapes

In our recently published paper we studied the effect of historical landscape changes on plant and arthropod communities harboured by grassland habitat islands.

Deák, B., Bede, Á., Rádai, Z., Tóthmérész, B., Török, P., Nagy, D.D., Torma, A., Lőrinczi, G., Nagy, A., Mizser, S., Kelemen, A., Valkó, O. (2021): Different extinction debts among plants and arthropods after loss of grassland amount and connectivity. Biological Conservation 264: 109372. doi: 10.1016/j.biocon.2021.109372.

The paper is open access and can be freely downloaded from here. 

Loss and fragmentation of natural and semi-natural habitats pose a major threat for biodiversity worldwide. Their effect are often coupled with additional effects (such as altered abiotic conditions, abandonment, invasion of plant and animal species) that lead to the degradation of the habitat, which on the one hand threatens the survival and reproduction of habitat specialist species and on the other hand supports the establishment of generalists. Habitat loss, fragmentation and degradation often lead to a decrease in population size and fitness of habitat specialist species that can finally result in the local extinction of area- and disturbance-sensitive species. However, such extinction processes are not necessarily immediate. Many populations show a delayed extinction causing an 'extinction debt' that is typical of recently fragmented landscapes in which the area and/or the spatial configuration of the habitat fragments are just below the extinction threshold for certain species. Existence of extinction debt can be assumed when the characteristics of the past landscape explain current species richness better than the characteristics of the present landscape.

In our study we aimed to explore the temporal dimensions of extinction debt across plant and arthropod taxa (ants, orthopterans, true bugs and rove beetles) in grassland habitat islands embedded in agricultural landscapes. We related the species richness of habitat specialist and generalist species to the current and past landscape metrics referring to the total grassland area and patch connectivity in the surroundings of the focal patch. We collected data from 60 dry focal grassland fragments (situated on ancient burial mounds so called 'kurgans'). Our study covered a period of 158 years including four time periods.

Grassland habitat island on an ancient burial mound.

We hypothesised that (i) historical landscape factors explain the current species richness of habitat specialists more than that of generalists, (ii) habitat connectivity has a larger effect on specialist species than habitat amount and (iii) area and environmental heterogeneity of the focal grassland patch increase the relaxation time of specialists whereas encroachment of woody species decreases it.

Map of the surveyed grassland fragments (n = 60). Changes in the grassland cover around one of the studied focal habitat patches over time: B – (1858–1864), C – (1881–1884), D – (1956–1975), E – (2014–2016).

We found that in the study area the amount of dry grasslands has been declining constantly from the 1850s until present days. Interestingly, the constant loss of habitats during the four studied periods did not result in a significant loss of habitat connectivity for an extended time interval during the first three periods (from 1858 to 1975). Even habitat loss accelerated after the WW II, the still existing network of farms and the related heterogeneous land use system with the many small grassland fragments could hinder the loss of connectivity. Habitat loss was severe in the later phase of the communist era and during the change of regime in the 1990s when crop monocultures appeared.

Effect of grassland amount and connectivity on the species richness of specialist (green dots) and generalist (grey dots) plant species in Periods III–IV. Solid lines represent significant, dashed lines non-significant relationships.

In our study sites current species richness of specialist plants correlated stronger with grassland amount and connectivity typical to the landscape five to seven decades ago than with present landscape characteristics. And the effect of past grassland connectivity was larger on specialist plants than the effect of past grassland amount, likely because loss of connectivity in recent times had more severe effect on the functional connections of remaining populations. The fact that the populations of specialist plants in the focal habitat patches still have not come to equilibrium with the attributes of the present landscape suggests that further extinctions can be expected especially in the case of specialist species sensitive to the loss of metapopulation connections. The reason for the long relaxation time is that in general, plants as sessile organisms react slowly to changes in the neighbouring landscapes and in local conditions. Traits typical to many plant species such as long life-span, ability for clonal reproduction, possession of seed banks can support the long time survival of plant species even under altered environmental conditions leading to a considerable time lag between the changes in landscape changes and changes in the species composition of specialist plant assemblies.

Interestingly high slope inclination that is a good proxy for high environmental heterogeneity (see also in Deák et al. 2021 Science of the Total Environment), had a significant positive effect on the species richness of specialist plants and assumed to mitigate extinction process (and increased time lag). The reason for that might be that high environmental heterogeneity expressed in topographic, micro-climatic heterogeneity and heterogeneity in soil properties can also increase the chance for the long-term persistence of plants within the focal grassland patch since even short distance disperser plant species can achieve short shifts within the focal habitat to establish in the microsite that is edaphically and climatically most favourable for them.

In contrast to specialist plants, the species richness of the studied specialist animal taxa (ants, orthopterans, true bugs and rove beetles) was not related to grassland amount or connectivity; thus, they were either unaffected by landscape changes or have already paid their extinction debt induced by landscape transformations in the past. The reason for that is despite plants, animals can actively disperse and leave habitats that have become unsuitable due to unfavourable changes. However, when animals are not able to relocate to another suitable habitat patch, local extinction processes might be much faster for them because of their short life cycles and high sensitivity to the lack of metapopulation connections.

However, the fact that dry grassland specialist plants showed a partially paid extinction debt suggests that their observed current species richness is not in equilibrium with the composition and configuration of the present landscape yet. This can be considered an early warning signal suggesting that even if grassland loss will be reduced in the landscape, further extinctions may be expected, which will reduce the biodiversity of the focal habitat fragment and also the biodiversity of specialist plants on a landscape level. Mitigating these negative processes should be considered a conservation priority as in heavily fragmented lowland agricultural landscapes, a considerable amount of grassland-specific species is only maintained by small habitat islands.

Abstract

A decrease in habitat amount and connectivity causes immediate or delayed species extinctions in transformed landscapes due to reduced functional connections among populations and altered environmental conditions. We assessed the effects of present and historical grassland amount and connectivity as well as local habitat factors typical of the present landscape on the current species richness of grassland specialist and generalist plants and arthropods in grassland fragments. We surveyed herbaceous plants, ants, orthopterans, true bugs and rove beetles in 60 dry grassland fragments in Hungary. We recorded the area of the focal grassland, the slope and the cover of woody vegetation. By using habitat maps of the present and historical landscape, we calculated grassland amount and connectivity for four time periods covering 158 years (1858–2016). We found evidence for an unpaid extinction debt in specialist plants, suggesting that they have not come to equilibrium with the grassland amount and connectivity of the present landscape yet. This localised and typically long-lived group responded slowly to the landscape changes. Specialist arthropod taxa with short generation times responded much faster to habitat loss than plants and did not show an extinction debt. Generalist plants and animals adapted to a wide range of habitats were affected by the landscape-scale decline of grassland habitats. Despite decreased habitat connectivity, grassland fragments with dry environmental conditions and high environmental heterogeneity can sustain specialist plants in transformed landscapes. Unpaid extinction debt should be considered an early warning signal: Restoration of grassland connectivity is necessary to halt ongoing extinction processes.

Grassland special issue in Tuexenia, and two new papers about grassland management from our group

The new issue of the Tuexenia journal has been launched, including the new grassland-related special feature of the Eurasian Dry Grassland Group, edited by Steffen Boch, Thomas Becker, Balázs Deák, Jürgen Dengler and Valentin Klaus.

The editorial paper introducing the specia feature can be downloaded by clicking here.

Boch, S., Becker, T., Deák, B., Dengler, J. & Klaus, V.H. (2021): Grasslands of temperate Europe in a changing world – Editorial to the 16th EDGG Special Feature in Tuexenia. – Tuexenia 41: 351–359.

The special feature includes two papers co-authored by members of our research group.

In the study by Judit Bódis et al., we compared the effects of traditional (mowing), alternative (mowing without hay removal, burning) management types and abandonment on the vegetation of fen meadows. 

The four management types applied in our experiment in the fen meadows in West-Hungary. Photos by Bálint Pacsai.

The citation of the paper:

Bódis, J., Fülöp, B., Lábadi, V., Mészáros, A., Pacsai, B., Svajda, P., Valkó, O. & Kelemen, A. (2021): One year of conservation management is not sufficient for increasing the conservation value of abandoned fen meadows. – Tuexenia 41: 381–394.

The paper is freely available and can be downloaded by clicking here.

 

The first paper from the grazing preference studies led by András Kelemen has been published by Nóra Balogh et al. about the consumption rate and dietary choice of cattle in a highly diverse meadow steppe system.

Sampling setup of the grazing preference study - photos by András Kelemen.

The citation of the paper:

Balogh, N., Tóthmérész, B., Valkó, O., Deák, B., Tóth, K., Molnár, Z., Vadász, C., Tóth, E., Kiss, R., Sonkoly, J., Antal, K., Tüdősné Budai, J., Miglécz, T. & Kelemen, A. (2021): Consumption rate and dietary preference of cattle in species-rich mesic grasslands. – Tuexenia 41: 395–410.

The paper is freely available and can be downloaded by clicking here.