Biodiversity of fragmented dry grasslands - Our new paper in Biodiversity and Conservation

In our new paper, recently published in Biodiversity and Conservation, we compared the species and phylogenetic diversity of patch-like and linear fragmented dry grasslands in agricultural landscapes.

The paper is freely available in the journal's homepage; please click here to download.

Deák, B., Rádai, Z., Lukács, K., Kelemen, A., Kiss, R., Báthori, Z., Kiss, P.J., Valkó, O. (2020): Fragmented dry grasslands preserve unique components of species and phylogenetic diversity in agricultural landscapes. Biodiversity and Conservation doi: 10.1007/s10531-020-02066-7 

Abstract

In intensively used landscapes biodiversity is often restricted to fragmented habitats. Exploring the biodiversity potential of habitat fragments is essential in order to reveal their complementary role in maintaining landscape-scale biodiversity. We investigated the conservation potential of dry grassland fragments in the Great Hungarian Plain, i.e. patch-like habitats on ancient burial mounds and linear-shaped habitats in verges, and compared them to continuous grasslands. We focused on plant taxonomic diversity, species richness of specialists, generalists and weeds, and the phylogenetic diversity conserved in the habitats. Verges meshing the landscape are characterised by a small core area and high level of disturbance. Their species pool was more similar to grasslands than mounds due to the lack of dispersal limitations. They held high species richness of weeds and generalists and only few specialists. Verges preserved only a small proportion of the evolutionary history of specialists, which were evenly distributed between the clades. Isolated mounds are characterised by a small area, a high level of environmental heterogeneity, and a low level of disturbance. Steep slopes of species accumulation curves suggest that high environmental heterogeneity likely contributes to the high species richness of specialists on mounds. Mounds preserved the same amount of phylogenetic diversity represented by the branch-lengths as grasslands. Abundance-weighted evolutionary distinctiveness of specialists was more clustered in these habitats due to the special habitat conditions. For the protection of specialists in transformed landscapes it is essential to focus efforts on preserving both patch-like and linear grassland fragments containing additional components of biodiversity.

Species rich grassland vegetation on the Erdő-mound

The verges of roads and railroads can provide safe havens for grassland species
even in transformed landscapes

Kurgan restoration - a pilot project in the Hortobágy National Park

Involvement of kurgans into the system of agricultural subsidies was an important step forward in preserving these iconic landscape elements. According to the regulations, in Hungary, farmers are not allowed to plough the kurgans (although it was typical case in the past), but they can consider the area of the kurgans as a part of the ecological focus areas (which result in an increase in the received subsidies). This construction can support the preservation of the structure of the kurgans in the whole country. However, for restoring grassland habitats on kurgans and improve their important role as significant landscape elements further active measures are needed. In the case of formerly ploughed kurgans this step is the restoration of dry grassland habitats on kurgans. Restored grassland vegetation can mitigate the populations of weed species on the abandoned kurgans and by active plant introduction also several grassland species can be established on the kurgans with a relatively low cost. Reduction of weeds can increase the landscape value of the kurgans and also profitable for the farmers as the suppression of weeds on the kurgan also decreases the amount of weeds in the neighbouring crops. The established grassland species can increase the landscape-scale biodiversity, and the restored grassland patches can be essential elements of the landscape-scale network of semi-natural habitats.

Our research group together with the colleagues from the Hortobágy National Park Directorate aimed to restore the grassland vegetation of two kurgans (Hegyes and Kishegyes mounds) near the settlement of Püspökladány. You can read about our former similar project here.

The sown grassland of the Hegyes mound; in the distance the smaller Kishegyes mound.

After the cessation of ploughing, both kurgans were sown by Festuca pseudovina which resulted in a closed grass cover on the kurgans hindering weed encroachment. Since the kurgans were quite a distance from the neighbouring natural grasslands, the spontaneous immigration of grassland plants to the kurgans was very slow. That is why in this year we applied active seed sowing to support this process. We sowed the seeds typical to local loess grasslands (Agropyron cristatum, Salvia austriaca, S. nemorosa, Filipendula vulgaris, Phlomis tuberosa and Dianthus pontederae) in small open patches (you can see our related post about the application of establishment gaps in sown grasslands here). For this we used the soil disturbances by small mammals and foxes, which due to their burrowing activity opened the otherwise closed grassland "mat" and prepared small scale soil disturbances. (You can read our paper about the effect of fox burrows on the populations of grassland species on kurgans here). Agropyron cristatum was sown on the top of the mounds, since in natural conditions this species often forms monodominant patches in this micro-habitat. The forb species were sown as a seed mixture into the open patches on the slopes. We hope that these species can establish successfully in the establishment gaps, and later they can be abundant on the kurgans. To support this process, an extensive grazing system will be introduced on the kurgans: in autumn, after the crop is harvested the mounds will be managed by cattle grazing.

  

A short meeting before we started to work.

Preparation of establishment windows (1).

Preparation of establishment windows (2).

Seed mixture (1).

Seed mixture (2).

Hand sowing (1).

Hand sowing (2).

Sown seeds of Agropyron cristatum.

After the sowing we used raking to provide a shallow soil cover for the sown species.

The team (from left to the right: Orsolya Valkó, Balázs Deák, Károly Hoffmann, Katalin Lukács and Réka Kiss).

Migrating cranes above the Hegyes mound.

New projects and awards in our research group

 

Recently we received good news about project proposals of the members of our research group: Balázs Deák won a 4-year grant of the National Research, Innovation and Development Office, Orsolya Valkó was awarded by the prestigious Bolyai Plaquette, Réka Kiss and Laura Godó won the Scholarship for Young Talents of Hungary.

We introduce briefly all the four projects below.

NKFI FK 135329: Taxonomic, trait and phylogenetic diversity of grassland plant communities in fragmented landscapes

In the project, Balázs Deák aims to reveal the habitat- and landscape-scale factors affecting the biodiversity of grassland habitats. Land use transformation and intensification have become major threats to biodiversity at multiple scales leading to the loss and transformation of natural habitats. This process dramatically reduced the area of grassland habitats; thus, conservation importance of remaining grassland fragments increased considerably. In this project focusing on grassland habitats in transformed landscapes, we aim to reveal the drivers of grassland biodiversity acting on the habitat (i.e. habitat size, habitat shape and environmental heterogeneity) and landscape scale (i.e. landscape composition and habitat connectivity). In order to understand mechanisms affecting grassland community assembly in European agricultural landscapes we focus our studies on four typical types of grasslands: extensive natural grasslands, grasslands on linear landscape elements, habitat islands and spontaneously regenerting grasslands. We aim to integrate three widely applied biodiversity components (taxonomic, functional and phylogenetic diversity) into a coherent and comprehensive analytical framework. By this approach on the one hand we can provide insights into the mechanisms how factors influence biodiversity and community assembly processes in natural and regenerating grasslands, and on the other hand we can study the potential relationships between the different biodiversity components. To fulfil this aim we plan a multi-scale, multi-site study using a trait- and phylogeny-based approach answering both theoretical ecological questions, and providing evidence-based implications for strategic nature conservation planning and for fine-tuning agri-environmental schemes.

 

Kurgans often harbour species-rich dry grasslands also in intensively used agricultural landscapes. Photo: Balázs Deák

Kurgan with species-rich grassland embedded in a cereal field. Photo: Balázs Deák.

Bolyai Plaquette - The role of soil seed bank in vegetation dynamics and recovery

Orsolya Valkó was awarded by the prestigious Bolyai Plaquette Award of the Hungarian Academy of Sciences. As a past Bolyai awardee, between 2016-2019 she was studying the role of soil seed bank in the vegetation dynamics and restoration of grassland ecosystems. The Plaquette is a prestigious recognition for the past awardees: this year, the most successful 14 researchers were awarded out of the 184 former Bolyai-scholars whose project ended in 2019.

Seedling of the wild carrot (Daucus carota). Photo: Tamás Miglécz.

Young Talents of Hungary - The effect of climatic changes on the population dynamics of a strictly protected geophyte species

In the project, Réka Kiss will focus on the population dynamics of the spring meadow saffron (Bulbocodium vernum), an early spring geophyte species marked as ‘Vulnerable’ in the Carpathian Basin and ‘Critically Endangered’ in Hungary. Being one of the first flowering plants in spring, in the past it was intensively collected; this fact together with the destruction of its natural habitats resulted in the severe decline and in some cases extinction of its populations. Human-mediated and natural processes, as well as climatic changes further threaten the survival of the species in Hungary. In the project we monitor the population dynamics of the spring meadow saffron, and correlate it with climatic parameters, in order to understand the effect of climatic changes on the populations. The results can contribute to the protection of this endangered species. 

The spring meadow saffron. Photo: Szilvia Radócz.

Réka Kiss, Katalin Lukács and the spring meadow saffron :) Photo: Szilvia Radócz.

Young Talents of Hungary -  "One swallow does not make a summer": the role of swallows and storks in seed dispersal

In the project, Laura Godó will study the role of rural birds, such as swallows and the White Stork in seed dispersal. Birds play an important role in seed dispersal, both via feeding (endozoochory and synzoochory) and on their body surface (epizoochory). Seed dispersal by nest material (caliochory) is a less studied phenomenon. In this project we will study the seed dispersal by nest material of swallows, i.e. the Barn Swallow (Hirundo rustica) and Common House Martin (Delichon urbica) with nests built from mud, and the White Stork (Ciconia ciconia) with large nest built from branches and herbaceous plants. We will also study the role of the nests in shaping the plant species composition of rural settlements.

White Stork (Ciconia ciconia) while bringing nest material. Photo: Laura Godó.

Barn swallow (Hirundo rustica) while collecting mud for nest building. Photo: Sándor Borza.

Laundry washing increases dispersal efficiency of cloth-dispersed propagules - our new paper in NeoBiota

 

In our recently published paper, we study an interesting ecological phenomenon in our everyday life, namely the fate of propagules attached to our clothing after laundry washing.

The paper has been published in the journal NeoBiota and can be freely downloaded by clicking here.

Valkó, O., Lukács, K., Deák, B., Kiss, R., Miglécz, T., Tóth, K., Tóth, Á., Godó, L., Radócz, Sz., Sonkoly, J., Kelemen, A., Tóthmérész, B. (2020): Laundry washing increases dispersal efficiency of cloth-dispersed propagules. NeoBiota 60: 1-16.

During fieldwork, excursions or outdoor sports we often notice a large number of seeds or other propagules attached on our clothing and footwear. Several species developed adaptations that support the attachment of their propagules on mammals fur, such as hooks, awns, spikes or glabrous surface. The propagules of these species can travel long distances via epizoochory, and are often attached also on our clothing.

After a field trip, we can find many propagules on our clothing and footwear.

 

Epianthropochory, i.e. dispersal of propagules on human clothing is a special case of epizoochory. We people are unique dispersal vectors as we can connect distant habitats which would not have any biological connections otherwise, for example we move between big cities and natural ecosystems, we can move between distant biogeographical regions or even between continents. Due to the increased global population and mobility, people became very abundant long-distance dispersal vectors for plant propagules.

There are many open questions regarding the fate of human-dispersed propagules, especially regarding their establishment prospects. It is still a question how the mechanical and chemical effects to which propagules are exposed during human-mediated dispersal, affect their germination potential and establishment prospects. One of the most drastic events that can happen to a clothing-dispersed propagule is laundry washing. Everyday observations of field biologists, hikers and people participating in outdoor sports show that propagules attached to clothing often end up in washing machine. In our study we asked the following questions: Do clothing-dispersed propagules remain germinable after laundry washing? What are the effects of washing intensity and washing medium on the germination? Are there differences in the germination dynamics in the washed and unwashed (control) seeds?

 

We selected 18 model species, all of them are widespread in Central-Europe and have some morphological adaptations for epizoochory. During the germination experiments, we applied six combinations of washing intensity (30 °C or 60 °C) and washing medium (water, soap nuts or detergent) and an unwashed (control) treatment. We had five replicates of 25 propagules per species and treatment.

We put the propagules into these fabric sacks. We sewed the sacks and appended them with a string to prevent the propagules escaping. We washed the sacks subjected to the six washing treatments in six separate laundry cycles.

Propagules of Arctium lappa that have already started to germinate during the intensive washing treatment.

There were a lot of germinated seedlings one month after the start of the experiment.

This group photo showes the germinated seedlings of Bromus sterilis. Each column contains pots with the same treatment. From the left to the right: column 1 is the control, columns 2-4 are the gentle washing and columns 5-7 are the intensive washing treatments.

Similar group photo of Physocaulis nodosus seedlings. You can see that after washing at 60 C, no seeds could germinate.

Our results showed that gentle washing at 30 C did not decrease the germination potential of any of the studied species compared to the unwashed control! Intensive washing at 60 C decreased the germination potential of the half of the studied species, but for the other half, it was neutral. Our results suggest that, in general, the new trend for using lower washing temperatures to reduce energy consumption probably increases the ratio of viable propagules that leave the laundry cycle.

We showed that intensive washing desynchronised the germination of eight species. Compared to the classical case of epizoochory on mammal’s fur, here the dispersal process itself has direct effects on germination dynamics. These effects of laundry washing on germination dynamics have important consequences for establishment: elongated and desynchronised germination is especially advantageous in unstable environments characterised by frequent and unpredictable disturbances, although it is disadvantageous for establishment in stable or harsh environments. If germination is desynchronised, there is a higher chance that at least some seeds will germinate under the most suitable conditions in a new environment.

We also studied the retention potential of dry propagules and also of propagules after washing and drying. We found that a considerable amount of propagules has the potential to enter the laundry cycle, especially in the case of cotton and fleece clothing. We found that washed propagules had even higher retention rates compared to dry ones; thus, laundry washing increases potential dispersal distances for a fraction of the propagules that remain attached even after washing. The retention rates of dry and washed propagules were influenced by species identity, being the longest for species with the most developed appendages.

 On the fruits of Agrimonia eupatoria, hairs and hooks support attachment on fur, or in our case, clothing.

The involucrum of Arctium lappa has many hooks which can attach very strongly to fur or fabrics.

Propagules of Daucus carota attached on cotton socks.

What is the final destination of the washed propagules? Our results suggest that there are two main directions of post-washing dispersal. Propagules that are detached during drying of the clothes probably get into rural or urban environments or some of them do not get outside of the houses. As urban habitats often provide suitable conditions for the establishment of alien species, it is possible that some of the seeds will germinate and establish in urban habitats and it is also possible that some might become urban invaders. Urban habitats are often considered as invasion hotspots, from where invasive alien species can arrive in periurban areas and later in natural habitats.

Those propagules that remain attached on clothes after drying have the potential for post-laundry long-distance dispersal. We showed that, after laundry washing and drying, there is a fraction of the washed propagules that attach better to the clothes than the dry ones. The transport of washed propagules on the clothes to natural ecosystems is a realistic threat if we consider that we wear outdoor clothes primarily during outdoor activities and therefore propagules have a high chance to be dispersed outdoors.

Globally, the largest mass invasion events are connected with transport by vehicles, construction of roads and buildings, international trade and agriculture; all these processes move a considerable amount of soil, plants and animals over large distances and contain a large number of viable propagules. Clothing-dispersal can also transport a large number of propagules from native ranges to new areas, if we consider the increasing size and mobility of the human population. However, the most important feature of clothing-dispersal is that it can also affect the relatively undisturbed nature reserves which are not exposed to the above-mentioned mass invasions caused by vehicles, construction works, trade or agriculture. Long-distance dispersal after laundry washing might be a major source of plant invasions in such reserves, hiking areas and other remote locations having a unique flora.

In such isolated ares, like this isolated mountain peak on an oceanic island, the most probable way of the arrival of propagules of non-native species is clothing-dispersal.

Mountains and islands harbour a considerable amount of biodiversity worldwide, but they are also under an increasing pressure by tourism. Geographical isolation and the harsh environmental conditions were able to prevent the spread of invasive alien species in these areas in the past, but due to the increased human pressure and climatic changes, these areas have recently become increasingly threatened by plant invasions. The dispersal mode described in our study can further aggravate this process and increase the vulnerability of these ecosystems to invasions: washing of clothing-dispersed propagules might increase the dispersal distances and also affect their germination dynamics. In this way, laundry washing can support invasive alien species in a new environment to overcome both propagule and establishment limitations, those factors that controlled their establishment in the past.

To decrease the chances for dispersing propagules on our clothing, we suggest a few simple precautional measures. When visiting nautre reserves, we recommend wearing of closed and waterproof clothing, made of fabrics with low retention potential. Also, it is important not picking and leaving the attached propagules on natural sites.