European Grasslands Research Articles

Tetracycline but not sulfamethazine inhibits early root growth of wild grassland species, while seed germination is hardly affected by either antibiotic

Seed germination and early growth of grassland species might be influenced by veterinary antibiotics that are extensively released into agricultural habitats. Therefore, we tested impacts of the commonly used antibiotics tetracycline and sulfamethazine, single and in mixture, on seed germination and seedling root growth of six typical species of temperate European grasslands (Carum carvi, Centaurea jacea, Galium mollugo, Plantago lanceolata, Silene latifolia, Dactylis glomerata). In standardised germination experiments, we assessed three germination variables (germination percentage, mean germination time, synchrony of germination) and one post-germination variable (seedling root length) under different environmentally realistic antibiotic concentrations (0.1, 1, 10 mg l−1 and a water control). While the germination variables were only irregularly and weakly affected by both antibiotics, seedling root length was strongly reduced by tetracycline, but not by sulfamethazine. Among the test species, D. glomerata was most sensitive to tetracycline with the average root length reduced up to 81 % in the 10 mg l−1 treatment. Its germination behaviour, however, was almost insensitive to the two antibiotics. Mixture effects were only shown in relation to the germination of single species, where the binary mixture produced effects but not the two single antibiotics or, conversely, effects of single antibiotics were lost in the mixture. These findings highlight the potential threat of plant regeneration from seed by veterinary antibiotics, particularly affecting early root growth and potentially influencing plant population growth in natural habitats.

Agricultural practices and biodiversity: Conservation policies for semi-natural grasslands in Europe

Europe's semi-natural grasslands support notably high levels of temperate biodiversity across multiple taxonomic groups. However, these ecosystems face unique conservation challenges. Contemporary agricultural practices have replaced historical traditional low-intensity agriculture in many regions, resulting in a spectrum of management intensities within these ecosystems, ranging from highly intensive methods to complete abandonment. Paradoxically, both extremes along this spectrum of management intensity can be detrimental to biodiversity of semi-natural grasslands. Moreover, while anthropogenic climate change is an overarching threat to these ecosystems, rapid changes in land use and its intensity often present more immediate pressures. Often occurring at a faster rate than climate change itself, these land-use changes have the potential to rapidly impact the biodiversity of these grasslands. Here, we divide the ecological processes, threats, and developments to semi-natural grasslands into three sections. First, we examine the different impacts of agricultural intensification and abandonment on these ecosystems, considering their different consequences for biodiversity. Second, we review seminal works on various evidence-based management practices and offer a concise summary that provides support for various conservation and management strategies. However, the socio-economic factors that drive both abandonment and intensification in semi-natural grasslands can also be used to develop solutions through strategic governmental and non-governmental interventions. Accordingly, we conclude with a way forward by providing several key policy recommendations. By synthesizing existing knowledge and identifying research gaps, this essay aims to provide valuable insights for advancing the sustainable management of semi-natural grasslands.

Assessing the environmental footprint of alternative green biorefinery protein extraction techniques from grasses and legumes

The significant grasslands of Europe and its member states represents a significant feedstock opportunity for circular bioeconomy development. The development of green biorefineries (GBR), to supply protein for the feed industry from grass, could help many European member states to address significant deficits in protein availability and reduce imports. The current study assesses the environmental footprint of alternative GBR protein extraction techniques from grasses and legumes using life cycle assessment. The focus is on comparing feedstock and technology pathways that could displace soya bean imports. The study finds that leaf protein concentrate (LPC) produced from grass had an improved environmental performance when compared to soya bean meal (SBM), across the assessed feedstock (perennial ryegrass or grass-clover mixtures) and technology pathways (one-stage maceration versus multi-stage maceration). For example, in the case of Climate Change the emission intensity for LPC was 57–85 % lower per tonne of crude protein (CP) compared with SBM. Acidification burdens were 54–88 % lower, and Eutrophication: Freshwater burdens were 74–89 % lower. Some scenarios of GBR produced LPC with a larger Energy Resources: Non-Renewable burden than SBM, though this could be mitigated with higher renewable energy (biogas and wind energy) integration within the scenario. Grass-clover scenarios generally achieved a lower intensity of emissions compared to ryegrass scenarios, particularly in the category of Climate Change, where feedstock cultivation represented a significant contributor to impacts. Overall, GBR can produce high quality protein with a lower environmental burden than SBM, but choice of feedstock and system design are critical factors for overall environmental performance.

Strengthened plant-microorganism interaction after topsoil removal cause more deterministic microbial assembly processes and increased soil nitrogen mineralization

Topsoil removal, among other restoration measures, has been recognized as one of the most successful methods to restore biodiversity and ecosystem functioning in European grasslands. However, knowledge about how removal as well as other restoration methods influence interactions between plant and microbial communities is very limited. The aims of the current study were to understand the impact of topsoil removal on plant-microorganism interactions and on soil nitrogen (N) mineralization, as one example of ecosystem functioning. We examined how three different grassland restoration methods, namely ‘Harvest only’, ‘Topsoil removal’ and ‘Topsoil removal + Propagules (plant seed addition)’, affected i) the interactions between plants and soil microorganisms, ii) soil microbial community assembly processes, and iii) soil N mineralization. We compared the outcome of these three restoration methods to initial degraded and target semi-natural grasslands in the Canton of Zurich, Switzerland. We were able to show that ‘Topsoil removal’ and ‘Topsoil removal + Propagules’, but not ‘Harvest only’, reduced the soil total N pool and available N concentration, but increased soil N mineralization and strengthened the plant-microorganism interactions. Microbial community assembly processes shifted towards more deterministic after both topsoil removal treatments. These shifts could be attributed to an increase in dispersal limitation and selection due to stronger interactions between plants and soil microorganisms. The negative relationship between soil N mineralization and microbial community stochasticity indicated that microbial assembly processes, to some extent, can be incorporated into model predictions of soil functions. Overall, the results suggest that topsoil removal may change the microbial assembly processes and thus the functioning of grassland ecosystems by enhancing the interaction between plants and soil microorganisms.

Phylogenetic relationships and plant life stage but not biogeographic history mediate priority effects of European grassland plants

Abstract The timing and order of species arrival have been shown to be a significant factor in the assembly of biotic communities. Therefore, understanding priority effects, which refer to the impact of an early‐arriving species on a later‐arriving one, can help us better predict community assembly processes. However, little is known about the role of phylogenetic distance (PD) in priority effects and how they are mediated by the biogeographic history (BH) and the life stages (LSs) of interacting species. To shed light on the role of PD in priority effects, we conducted a multispecies greenhouse experiment. We created 10 allopatric and 10 sympatric species pairs, representing a PD gradient between early‐ and late‐arriving species from 5 to 270 Myr in evolutionary history and tested the priority effect of early‐arriving species on the late‐arriving species at multiple LSs. We found evidence of stronger competition between closely related species, as late‐arriving plants produced less above‐ground biomass when the PD was low. However, priority effects varied across the development of late‐arriving plants, as there were no effects on seedling emergence and survival, independent of PD. Regardless of PD, the pairs of allopatric and sympatric species did not differ in their responses. Synthesis. While many studies have produced contradictory results regarding the effect of PD on plant–plant interactions, our study provides experimental evidence that priority effects can be stronger when PD is small. This effect was independent of BH but varied across different LSs of late‐arriving plants. The dependence of the effect of PD on the LS of late‐arriving species highlights the importance of the timing of interactions for the assembly of plant communities, which could also have significant implications for the fields of invasion and restoration ecology.

Natural grazing by horses and cattle promotes bird diversity in a restored European alluvial grassland.

A challenge in grassland conservation is to maintain both the openness and the heterogeneity of the habitat to support the diversity of their animal communities, including birds-a taxon that is known to be sensitive to disturbance. An increasingly used management tool in European grassland conservation, especially in rewilding projects, is grazing by large herbivores such as horses and cattle. These grazers are believed to create and maintain patchy landscapes that promote diversity and richness of other species, but their influence on birds is often debated by conservationists, who raise concerns about the impact of disturbance by the grazers. Our aim was to examine the relationship between the abundance and species richness of birds across four foraging guilds and the area utilization patterns of Highland cattle and Konik horses in an alluvial grassland in France. We also aimed to examine the influence of land cover and season on the spatial distribution, including abundance and species richness, of different bird guilds present in the grazed area. We used GPS-collars on all grazers and recorded their positions on an hourly basis over a study period of 1.5 years, assessing patterns of area usage. We counted birds weekly along three transects to describe their distribution within the grazed area and carried out land-cover surveys to describe the habitat. To assess how species richness and abundance of birds of different guilds were related to grazer density, season, and habitat characteristics, we used GAMM models in a spatially explicit framework. We also compared bird numbers at our main study site with a nearby non-grazed control area. The number of birds in the grazed area was about twice the number in the non-grazed control area. Within the grazed area, the abundance of open-area foraging birds increased with increasing grazer density. The number of woodland-foraging birds was also positively correlated with grazer density but less so than open-area foraging birds. The number of individuals in the aerial and wetland bird guilds was not correlated with the density of grazers. Most bird species and individuals were observed on open landscapes scattered with woody patches and waterbodies, and on areas with moderate grazer density. Low-intensity grazing represents a potentially important management tool in creating heterogeneity in alluvial grasslands, thereby promoting suitable habitat for a diverse assemblage of bird species.

Prototype Biodiversity Digital Twin: grassland biodiversity dynamics

European grassland management has often favoured high production through frequent mowing and heavy fertilisation over biodiversity conservation, which is typically supported by less intensive management. Besides management, climate change and extremes are increasingly affecting grassland productivity and biodiversity, requiring timely adaptation of management practices. Here, we describe the development of a prototype Digital Twin (pDT) of grassland biodiversity dynamics intended to support researchers, farmers or regulatory decision-makers in monitoring the current state of selected grassland sites and projecting their future state under various management and climate scenarios.

Effect of plant communities on bacterial and fungal communities in a Central European grassland

BackgroundGrasslands provide fundamental ecosystem services that are supported by their plant diversity. However, the importance of plant taxonomic diversity for the diversity of other taxa in grasslands remains poorly understood. Here, we studied the associations between plant communities, soil chemistry and soil microbiome in a wooded meadow of Čertoryje (White Carpathians, Czech Republic), a European hotspot of plant species diversity.ResultsHigh plant diversity was associated with treeless grassland areas with high primary productivity and high contents of soil nitrogen and organic carbon. In contrast, low plant diversity occurred in grasslands near solitary trees and forest edges. Fungal communities differed between low-diversity and high-diversity grasslands more strongly than bacterial communities, while the difference in arbuscular mycorrhizal fungi (AMF) depended on their location in soil versus plant roots. Compared to grasslands with low plant diversity, high-diversity plant communities had a higher diversity of fungi including soil AMF, a different fungal and soil AMF community composition and higher bacterial and soil AMF biomass. Root AMF composition differed only slightly between grasslands with low and high plant diversity. Trees dominated the belowground plant community in low-diversity grasslands, which influenced microbial diversity and composition.ConclusionsThe determinants of microbiome abundance and composition in grasslands are complex. Soil chemistry mainly influenced bacterial communities, while plant community type mainly affected fungal (including AMF) communities. Further studies on the functional roles of microbial communities are needed to understand plant-soil-microbe interactions and their involvement in grassland ecosystem services.

Supportive effect of uncut refuge strips on grassland arthropods may depends on the amount and width of strips

Abstract Vast grassland areas disappear due to abandonment, conversion to arable fields or urban areas. Consequently, grassland species have declined dramatically during and since the last century. The majority of remaining European grasslands are managed, many of them by mowing, which, in general, decreases arthropods' abundance and species richness. Here, we aimed to study the effects of width and proportion of refuge areas on local abundance and richness of arthropods in hay meadows. Within a ca. 4000 ha semi‐natural grassland area of the Great Hungarian Plain, we established refuge strips of different widths (3 and 9 m) and proportion of total field area (10 and 25%) following a randomised block design with six replicates per treatment. We studied five arthropod groups (grasshoppers, true bugs, carabids and ground‐dwelling and vegetation‐dwelling spiders), which we sampled 2 weeks after mowing by sweep netting and pitfall traps. Uncut strips were warmer and moister than the mown areas. The effects of refuge strips and their arrangement were stronger on the vegetation‐dwelling than on ground‐dwelling arthropods, although all taxa were affected in some way. We found more true bugs in mown areas between narrow strips than between wide strips. The interaction effect of width and proportion of refuge strips on the abundance of grasshoppers, ground‐dwelling spiders and species richness of carabids showed that wider strips are more beneficial if their proportion is low and narrow strips are more beneficial with high proportion. Synthesis and applications: Our findings provide evidence that uncut refuge strips can harbour diverse and abundant arthropod assemblages in hay meadows and mitigate the adverse effects of uniformly executed mowing on arthropods. Modifying attributes and considering farming practices, wide strips with a low (10%) proportion of total field area seem optimal for both conservation and practitioners.

Development of insects in newly established grassland over six years: Increased conservation benefits through diverse plant communities

Agri-environmental schemes seek to mitigate the loss of biodiversity by subsidizing the restoration of grassland in Europe. However, little is known about the colonization of newly established grasslands by insects, especially over periods exceeding 1–2 years. Therefore, we investigated the development of species richness, abundance and species assemblages of wild bees, syrphids, butterflies, orthopterans and true bugs in two types of newly established grassland strips in an agricultural landscape in Austria over a six-year time span. We compared currently subsidized plant-species poor grassland strips (SG; Ecological Focus Areas) with newly established grassland strips (NG) that were created with a diverse, regionally adapted seed mixture, to find out whether diverse seed mixtures can ensure lasting improvements in the insect species richness of grassland strips over a 6-year period. We used permanent seminatural grasslands (old grassland OG) as reference habitat. From the first year after establishment, we found no differences in syrphid assemblages between OG and NG. In contrast, true bug assemblages in NG differed significantly from those in OG still five years after establishment. Wild bee, butterfly and orthopteran species composition differences between grassland strips (NG, SG) and permanent grasslands (OG) were decreasing over time. However, we found no evidence of a successional change in insect species assemblages in NG and SG. NG promoted a significantly higher wild bee richness and equivalent syrphid, butterfly, orthoptera and true bug richness compared with OG. Over the study period, NG showed sustained insect diversity, outperforming plant species-poor SG in promoting wild bee, syrphid and true bug richness. Therefore, we suggest that diverse and regional seed mixtures could enhance the effectiveness of grassland restoration for insect conservation and could make re-sowing within the first 6 years after establishment unnecessary.

Predicting the responses of European grassland communities to climate and land cover change.

European grasslands are among the most species-rich ecosystems on small spatial scales. However, human-induced activities like land use and climate change pose significant threats to this diversity. To explore how climate and land cover change will affect biodiversity and community composition in grassland ecosystems, we conducted joint species distribution models (SDMs) on the extensive vegetation-plot database sPlotOpen to project distributions of 1178 grassland species across Europe under current conditions and three future scenarios. We further compared model accuracy and computational efficiency between joint SDMs (JSDMs) and stacked SDMs, especially for rare species. Our results show that: (i) grassland communities in the mountain ranges are expected to suffer high rates of species loss, while those in western, northern and eastern Europe will experience substantial turnover; (ii) scaling anomalies were observed in the predicted species richness, reflecting regional differences in the dominant drivers of assembly processes; (iii) JSDMs did not outperform stacked SDMs in predictive power but demonstrated superior efficiency in model fitting and predicting; and (iv) incorporating co-occurrence datasets improved the model performance in predicting the distribution of rare species. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.

Large‐scale remote sensing analysis reveals an increasing coupling of grassland vitality to atmospheric water demand

AbstractGrasslands provide important ecosystem services to society, including biodiversity, water security, erosion control, and forage production. Grasslands are also vulnerable to droughts, rendering their future vitality under climate change uncertain. Yet, the grassland response to drought is not well understood, especially for heterogeneous Central European grasslands. We here fill this gap by quantifying the spatiotemporal sensitivity of grasslands to drought using a novel remote sensing dataset from Landsat/Sentinel‐2 paired with climate re‐analysis data. Specifically, we quantified annual grassland vitality at fine spatial scale and national extent (Germany) from 1985 to 2021. We analyzed grassland sensitivity to drought by testing for statistically robust links between grassland vitality and common drought indices. We furthermore explored the spatiotemporal variability of drought sensitivity for 12 grassland habitat types given their different biotic and abiotic features. Grassland vitality maps revealed a large‐scale reduction of grassland vitality during past droughts. The unprecedented drought of 2018–2019 stood out as the largest multi‐year vitality decline since the mid‐1980s. Grassland vitality was consistently coupled to drought (R2 = .09–.22) with Vapor Pressure Deficit explaining vitality best. This suggests that high atmospheric water demand, as observed during recent compounding drought and heatwave events, has major impacts on grassland vitality in Central Europe. We found a significant increase in drought sensitivity over time with highest sensitivities detected in periods of extremely high atmospheric water demand, suggesting that drought impacts on grasslands are becoming more severe with ongoing climate change. The spatial variability of grassland drought sensitivity was linked to different habitat types, with declining sensitivity from dry and mesic to wet habitats. Our study provides the first large‐scale, long‐term, and spatially explicit evidence of increasing drought sensitivities of Central European grasslands. With rising compound droughts and heatwaves under climate change, large‐scale grassland vitality loss, as in 2018–2019, will thus become more likely in the future.

Detecting flowers on imagery with computer vision to improve continental scale grassland biodiversity surveying

Abstract Large‐scale biodiversity monitoring is essential for assessing biodiversity trends, yet traditional surveying methods are limited in the spatial/temporal scale they can cover. Recent technological developments have led to computer vision‐based species identification tools, such as the Pl@ntNet application. Increasing accuracy of such algorithms presents an opportunity of integrating computer vision into larger monitoring schemes and could lead to automating ground‐based evidence provision related to agri‐environmental measures (e.g. flower strips, field margins). However, images from surveys or farmer declarations do not live up to the standards of current applications. In order to integrate these automated methods into biodiversity monitoring, more generalized models are needed. We create a dataset using 500 manually delineated images of vegetation patches in European grasslands taken during the Land Use/cover Area Survey (LUCAS) grassland module. We train the Faster R‐CNN model to detect and extract individual flower objects. Using this model, we extract the abundance of flowers in an image, analyse their colour distribution, and use the Pl@ntNet application to identify the species of the individual flowers detected. The best model reaches precision and recall of 0.89/0.61 and predicts 1377 flowers on the 100 test images distributed between 10 colours. Using Pl@ntNet, only 52 flowers were identified with a certainty score above 0.5 due to the limitations in image size and quality. Of these flowers, 30% were correctly automatically identified at the species level and 42% at the genus level. The results show that we can automatically extract valuable information on floral abundances, colours, and sizes from images of vegetation patches, though in most cases better images are needed for species identification. Despite limitations with image quality, integrating this workflow into large‐scale monitoring could speed up the sampling process and allow for better spatial and temporal data on floral diversity and abundance.

A set of ecosystem service indicators for European grasslands based on botanical surveys

AbstractBackgroundGrasslands provide a wide range of ecosystem services (ESs). However, there is currently no method for easily diagnosing the level of ESs produced. Our aim was to develop ES indicators based on botanical surveys, which are readily available data and integrative of grassland spatiotemporal variability.MethodsBased on academic knowledge and expertise, we identified several simple vegetation criteria that we aggregated using a multicriteria analysis tool to construct indicators of the level of ESs provided by grasslands. In this study, the indicators were calculated from over 2000 botanical surveys spread over a wide biogeographical gradient.ResultsAnalyses of correlation between the various indicators show that “forage supply” and “diversity conservation” were not correlated. “Forage availability” and “nitrogen availability for the vegetation” were positively linked together and negatively linked to the robustness of the plant community to extreme events. A temporal approach highlights that the “biodiversity conservation” score decreased from 1970 to 2010 and that “nitrogen availability for the vegetation” was lower in 1970 and 1980 than in 2000 and 2010.ConclusionsThese results show that our aggregation method based on a large data set of botanical surveys could be appropriate for studying temporal dynamics of ESs.

Drought induces moderate, diverse changes in the odour of grassland species

Plants react to drought stress with numerous changes including altered emissions of volatile organic compounds (VOC) from leaves, which provide protection against oxidative tissue damage and mediate numerous biotic interactions. Despite the share of grasslands in the terrestrial biosphere, their importance as carbon sinks and their contribution to global biodiversity, little is known about the influence of drought on VOC profiles of grassland species. Using coupled gas chromatography-mass spectrometry, we analysed the odorants emitted by 22 European grassland species exposed to an eight-week-lasting drought treatment (DT; 30% water holding capacity, WHC). We focused on the odorants emitted during the light phase from whole plant shoots in their vegetative stage. Emission rates were standardised to the dry weight of each shoot. Well-watered (WW) plants (70% WHC) served as control. Drought-induced significant changes included an increase in total emission rates of plant VOC in six and a decrease in three species. Diverging effects on the number of emitted VOC (chemical richness) or on the Shannon diversity of the VOC profiles were detected in 13 species. Biosynthetic pathways-targeted analyses revealed 13 species showing drought-induced higher emission rates of VOC from one, two, three, or four major biosynthetic pathways (lipoxygenase, shikimate, mevalonate and methylerythritol phosphate pathway), while six species exhibited reduced emission rates from one or two of these pathways. Similarity trees of odorant profiles and their drought-induced changes based on a biosynthetically informed distance metric did not match species phylogeny. However, a phylogenetic signal was detected for the amount of terpenoids released by the studied species under WW and DT conditions. A comparative analysis of emission rates of single compounds released by WW and DT plants revealed significant VOC profile dissimilarities in four species only. The moderate drought-induced changes in the odorant emissions of grassland species are discussed with respect to their impact on trophic interactions across the food web. (294 words)

Synergistic effects of grass competition and insect herbivory on the weed Rumex obtusifolius in an inundative biocontrol approach

Outcomes of weed biological control projects are highly variable, but a mechanistic understanding of how top-down and bottom-up factors influence the success of weed biological control is often lacking. We grew Rumex obtusifolius, the most prominent native weed in European grasslands, in the presence and absence of competition from the grass Lolium perenne and subjected it to herbivory through targeted inoculation with root-boring Pyropteron spp. To explore whether the interactive effects of competition and inundative biological control were size-dependent, R. obtusifolius was planted covering a large range of plant sizes found in managed grasslands. Overall, competition from the grass sward reduced aboveground biomass and final root mass of R. obtusifolius about 62- and 7.5-fold, respectively, and increased root decay of R. obtusifolius from 14 to 58%. Herbivory alone increased only root decay. However, grass competition significantly enhanced infestation by Pyropteron spp. and, as a consequence, enhanced the impact of herbivory on aboveground biomass and final root mass. The synergistic effect was so strong that R. obtusifolius plants grown from initially smaller roots did no longer develop. Inoculating R. obtusifolius with Pyropteron species in grasslands should be further pursued as a promising inundative biological control strategy in the weed’s native range.

Long-term patterns of grassland vegetation and species richness in a full-factorial NPK fertilization experiment

Species-rich grasslands contribute significantly to conserving environmental quality in Europe but have suffered for decades due to area reduction and degradation from nutrient addition of agricultural or pollution origins. Studying the effects of grassland fertilization can supply useful information on their degradation patterns and restoration possibilities.On a valley meadow in the Italian Alps fertilized with farmyard manure until 1976, a fertilization trial with 4 replicates and 27 treatments from the factorial combination of three levels of nitrogen (N), phosphorus (P) and potassium (K) was established in 1977 and surveyed until 2003 for botanical composition on 18 m2 plots. The change of species composition and species richness (SR) occurring over the surveying period was analyzed.Six types of vegetation successions were identified, mostly with homogeneous nutrient combinations and only marginal influence by the amount of nutrients added. In all successions, the vegetation change was significant compared to the pre-experiment situation and more rapid but less persistent for abundance than for presence-absence. From about 33.6 species per plot surveyed in 1976, SR had the highest increase in the succession with no-fertilization or only-P or only-K addition (40.2 species in the period 1991–2003). The N + P + K (27.2 species) and N + P (26.3 species) successions had the strongest negative impact on SR. In the other successions (N + K, P + K and only N) SR increased or decreased little. No soil acidification and no negative effect on SR from the acidifying N-fertilizer ammonium nitrate was observed thanks to the buffering power of the Ca‑carbonate soil content.In the two successions with the highest SR variation the SR changed rapidly in the first period but fluctuated later around a constant value. In the succession with significant but little SR variation, this trend was not obvious due to the considerable interannual SR fluctuation. In all successions, the SR change was the result of a balance between logarithmic trends of species loss and gain. Species loss was probably caused by stochastic extinction of low-abundance species, but in NP, it was also due to the establishment of the aggressive-growth-habit Festuca rubra. For species gain, the suitability of incoming species to new fertility conditions was an important factor.Trial results showed that in calcareous, permeable soils, the species richness of central European grassland is especially endangered by the combined addition of N and P (with or without K), more than the only-N addition. However, they also showed that the restoration of grassland that had been degraded due to high NPK inputs from agriculture and NP enrichment from water and atmosphere pollution is possible with the cessation of fertilization and without seed addition if the surrounding landscape is species-rich and plants with aggressive growth habits are not established. Management for grassland biodiversity conservation should avoid the utilization of soil-acidifying fertilizers, reducing the P input beside the N input and limiting the introduction and spreading of aggressive grass species, such as Festuca rubra.

Abandoning grassland management negatively influences plant but not bird or insect biodiversity in Europe

AbstractGrasslands are globally distributed and naturally occurring; however, in Europe, most grasslands are anthropogenically created or altered by livestock grazing or mowing. Low‐intensity use and management have led to species‐rich communities in European grasslands. The intensification of crop production and livestock farming with stabling throughout the year has led to an abandonment of grasslands that are no longer economically profitable. In this study, we looked at the influence of grassland abandonment on biodiversity. We hypothesized that abandonment of grasslands decreases the overall biodiversity, but has different effects depending on the focal taxonomic group (i.e., vascular plants, insects, or birds). We also hypothesized that the type of management before abandonment, the type of grassland, and the time after abandonment would influence grassland biodiversity. We conducted a Web of Science search, with pre‐defined terms, to find articles that compared biodiversity of managed and abandoned grasslands in Europe. We screened the articles and included 39 studies in a subsequent meta‐analysis. We found that overall biodiversity was reduced after abandonment; however, the biodiversity reduction in the grasslands differed among taxonomic groups. Plant species diversity was significantly lower after abandonment (plant summary effect size: −0.25 [−0.34; −0.16]), whereas the diversity of insects and birds showed no significant trend, but a visual trend toward an increase. None of the other environmental variables (type of management, type of grassland, or the time after abandonment) had a significant influence on the biodiversity of the grasslands. We conclude that maintaining grassland management is crucial to support biodiversity conservation in European grasslands.

Negative effects of EPDM microplastic and cork granules on plant growth are mitigated by earthworms and likely caused by their structural properties

Soil microplastic pollution can have negative effects on organisms, including plants, but the underlying mechanisms are not fully understood. We tested whether structural or chemical properties of a microplastic cause its effects on plant above- and belowground growth and whether these effects can be influenced by earthworms. We conducted a factorial experiment in a greenhouse with seven common Central European grassland species. Microplastic granules of the synthetic rubber ethylene propylene diene monomer (EPDM),11EPDM: ethylene propylene diene monomer. a frequently used infill material of artificial turfs, and cork granules with a comparable size and shape to the EPDM granules were used to test for structural effects of granules in general. To test for chemical effects, EPDM-infused fertilizer was used, which should have contained any leached water-soluble chemical components of EPDM. Two Lumbricus terrestris individuals were added to half of the pots, to test whether these earthworms modify effects of EPDM on plant growth. EPDM granules had a clear negative effect on plant growth, but since cork granules had a negative effect of similar magnitude, with an average decrease in biomass of 37 % in presence of granules, this is likely due to the structural properties of granules (i.e., size and shape). For some belowground plant traits, EPDM had a stronger effect than cork, which shows that there must be other factors playing into the effects of EPDM on plant growth. The EPDM-infused fertilizer did not have any significant effect on plant growth by itself, but it had in interaction with other treatments. Earthworms had an overall positive effect on plant growth and mitigated most of the negative effects of EPDM. Our study shows that EPDM microplastic can have negative effects on plant growth, and that these might be more related to its structural than to its chemical properties.

Catching up with the trees: empirical advancements to improve herbaceous representation in models.

This article is a Commentary on Curasi et al. (2023), 239: 562–575.