Species-rich Grasslands Research Articles

Hemiparasitic plants facilitate ecological restoration of encroached European grasslands.

Species-rich grasslands of temperate Europe are threatened by the spread and increasing dominance of the rhizomatous grass Calamagrostis epigejos. Native hemiparasitic Rhinanthus species have been proposed as biocontrol to suppress C. epigejos, but experimental evidence is limited. We conducted a series of experiments at 21 grassland sites in Central Europe encroached by C. epigejos to test the effects of Rhinanthus on C. epigejos and on plant and arthropod communities and compare them to the effects of mowing applied once or twice a year. Rhinanthus suppressed Calamagrostis epigejos significantly more than mowing. Mowing frequency and Rhinanthus sowing had synergistic effects, leading to an average 75% reduction of C. epigejos biomass in Rhinanthus plots that were mown twice during the three-to four-year experimental period. The effect was more pronounced at sites in dry climates. Both Rhinanthus and mowing significantly increased plant diversity. Rhinanthus plots mown twice changed most rapidly towards the target grassland vegetation. The abundance and species richness of arachnids and Auchenorrhyncha were generally higher in abandoned plots than in plots with active management. Rhinanthus plots harboured fewer grass-feeding insects but more forb-associated herbivorous Auchenorrhyncha and Heteroptera species and several heliophilous spiders. Our experiment showed that Rhinanthus spp., in combination with mowing, is an efficient and widely applicable method to reverse the encroachment of C. epigejos into grasslands and restore the diversity of infested plant communities. Active management measures also trigger a species turnover of arthropod communities, reflecting changes in grassland vegetation and arthropod guild species pools.

Bumblebee Abundance in Species-Rich Grasslands in Southern Sweden Decreases with Increasing Amount of Arable Land at a Landscape Level.

Conservation of bumblebee populations is essential because of their role as pollinators. Declines in bumblebee abundance have been documented in recent decades, mostly attributed to agricultural intensification, landscape simplification and loss of semi-natural grasslands. In this study, we investigated the effects of landscape composition on bumblebee abundance at different spatial scales in 476 semi-natural grassland sites in southern Sweden. The area of arable land had a negative effect on total bumblebee abundance at all scales. This was most pronounced for short-tongued bumblebees, species typical of forested landscapes, and species with medium to large colony sizes and early queen emergence. The area of semi-natural grassland had a clear negative effect up to 1 km, affecting short-tongued bumblebees in both forested and agricultural landscapes and species with medium colony sizes and early queen emergence. The negative effect of arable land on bumblebees calls for action to adapt farming practices to ensure their conservation, e.g., by reducing pesticide use, improving crop diversity and promoting the presence of floral resources and alternative bumblebee habitats, such as species-rich field margins.

Remotely Sensed Variables Predict Grassland Diversity Better at Scales Below 1,000 km as Opposed to Abiotic Variables That Predict It Better at Larger Scales

AbstractGlobal spatial patterns of vascular plant diversity have been mapped at coarse grain based on climate‐dominated environment–diversity relationships and, where possible, at finer grain using remote sensing. However, for grasslands with their small plant sizes, the limited availability of vegetation plot data has caused large uncertainties in fine‐grained mapping of species diversity. Here we used vegetation survey data from 1,609 field sites (>4,000 plots of 1 m2), remotely sensed data (ecosystem productivity and phenology, habitat heterogeneity, functional traits and spectral diversity), and abiotic data (water‐ and energy‐related, characterizing climate‐dominated environment) together with machine learning and spatial autoregressive models to predict and map grassland species richness per 100 m2 across the Mongolian Plateau at 500 m resolution. Combining all variables yielded a predictive accuracy of 69% compared with 64% using remotely sensed variables or 65% using abiotic variables alone. Among remotely sensed variables, functional traits showed the highest predictive power (55%) in species richness estimation, followed by productivity and phenology (48%), spectral diversity (48%) and habitat heterogeneity (48%). When considering spatial autocorrelation, remotely sensed variables explained 52% and abiotic variables explained 41%. Moreover, Remotely sensed variables provided better prediction at smaller grain size (<∼1,000 km), while water‐ and energy‐dominated macro‐environment variables were the most important drivers and dominated the effects of remotely sensed variables on diversity patterns at macro‐scale (>∼1,000 km). These findings indicate that while remotely sensed vegetation characteristics and climate‐dominated macro‐environment provide similar predictions for mapping grassland plant species richness, they offer complementary explanations across broad spatial scales.

Shallow drainage of agricultural peatlands without land-use change: have your peat and eat it too

IntroductionDrainage for agricultural purposes is one of the main drivers of peatland degradation, leading to significant greenhouse gas (GHG) emissions, biodiversity loss, and soil eutrophication. Rewetting is a potential solution to restore peatlands, but it generally requires a land-use shift to paludiculture or nature areas.MethodsThis study explored whether three different water level management techniques (subsoil irrigation, furrow irrigation, and dynamic ditch water level regulation) could be implemented on dairy grasslands to yield increases in essential ecosystem services (vegetation diversity and soil biogeochemistry) without the need to change the current land use or intensity. We investigated vegetation diversity, soil biogeochemistry, and CO2 emission reduction in fourteen agricultural livestock pastures on drained peat soils in Friesland (Netherlands).ResultsAcross all pastures, Shannon-Wiener diversity was below 1, and the species richness was below 5. The plant-available phosphorus (P) was consistently higher than 3 mmol L−1. None of the water level management (WLM) techniques enhanced vegetation diversity or changed soil biogeochemistry despite a notable increase in water table levels. The potential for CO2 emission reduction remained small or even absent. Indicators of land-use intensity (i.e., grass harvest and fertilization intensity), however, showed a strong negative correlation with vegetation diversity. Furthermore, all sites’ total and plant-available P and nitrate exceeded the upper threshold for species-rich grassland communities.DiscussionIn conclusion, our research suggests that incomplete rewetting (i.e., higher water tables while maintaining drainage) while continuing the current land use does neither effectively mitigate GHG emissions nor benefit vegetation diversity. Therefore, we conclude that combining WLM and reducing land-use intensity is essential to limit the degradation of peat soils and restore more biodiverse vegetation.

Between-year weather differences and long-term environmental trends both contribute to observed vegetation changes in a plot resurvey study.

Repeated surveys of vegetation plots offer a viable tool to detect fine-scale responses of vegetation to environmental changes. In this study, our aim was to explore how the species composition and species richness of dry grasslands changed over a period of 17 years, how these changes relate to environmental changes and how the presence of spring ephemerals, which may react to short-term weather fluctuations rather than long-term climatic trends, may influence the results. A total of 95 plots was surveyed in 2005 and resurveyed in 2022 in dry grasslands of the Kiskunság Sand Ridge (Hungary, Eastern Central Europe), where there has been a significant increase in mean annual temperature during the last decades, while no trends in precipitation can be identified. Db-RDA was performed to reveal compositional changes. The changes in environmental conditions and naturalness state were assessed using ecological and naturalness indicator values. We also compared per-plot richness of all species, native species and non-native species of the old and the new relevés. All analyses were repeated after removing all spring ephemerals. We found clear temporal changes in species composition. Mean temperature indicator values increased, while mean soil moisture indicator values decreased during the 17 years. Also, decreasing per-plot richness was detected both for all species and for native species, while mean naturalness increased. After the removal of spring ephemerals, the compositional changes were less obvious although still significant. The increase in the temperature indicator values remained significant even without the spring ephemerals. However, the decrease in the moisture indicator values, the decrease in the number of all species and native species, as well as the increase in naturalness indicator values disappeared when spring ephemerals were excluded from the analyses. Our study demonstrates that between-year weather differences and long-term environmental trends both contribute to observed vegetation changes.

A Link between Species Abundance and Plant Strategies for Semi-Natural Dry Grasslands.

Due of the potential of species to determine ecosystem properties, it is important to understand how species abundance influences community assembly. Using vegetation surveys on 35 dry grasslands in north-east Slovenia, we defined dominant (8) and subordinate (61) plant species. They were compared on 14 traits to test for differences in community-weighted mean (CWM) and functional diversity (FD). We found that dominants and subordinates differed strongly in their functional traits. Dominants showed higher leaf dry matter content and a more pronounced stress tolerance strategy and were all clonal with a large proportion of species with rhizomes and a rich bud bank, while other species showed a higher specific leaf area, a longer flowering period and more ruderals. For most traits, FD was higher in subordinates. Our results suggest that dominants drive community structure by limited susceptibility to non-competitive processes. Dominants may have positive effects on subordinates by mitigating environmental stressors. Subordinates are able to assemble together by being dissimilar and use different fine-scale niches that are engineered and homogenised by dominants. Our results show that there are fundamental differences in the relative importance of ecological processes between dominant and subordinate plants in species-rich grasslands, which is also important for their conservational management.

Relationship between extreme species richness and Holocene persistence of forest-steppe grasslands in Transylvania, Romania

The most species-rich grasslands worldwide are known from the Carpathian Mts and their periphery in East-Central Europe. They occur in forest-steppe regions, transitional between temperate forest and arid steppe biomes. Their climate, largely suitable for forests, raises questions about the origin of these grasslands. Have they been forested in the past, or locally maintained through a disturbance regime? We addressed these questions to contribute to the broader understanding of Holocene dynamics of open habitats in temperate Europe. We employed soil charcoal analysis and soil morphology to reconstruct past representation of woody species with fine spatial resolution. Our study area was Romanian Transylvania, a region renowned for a well-developed forest-steppe. Six soil profiles along a climatic gradient were assessed: four in forest-steppe grasslands, two in grasslands in adjacent forest region (forest grasslands). The results revealed profound differences between forest-steppe and forest grasslands. Forest-steppe profiles showed Phaeozems with low specific anthracomass of woody species and continuous dominance by Juniperus, suggesting a long-term presence of grasslands. Forest grasslands showed Luvisols with higher anthracomass and abundant charcoal of broad-leaved trees, indicating establishment after deforestation. The high radiocarbon ages of charcoals in basal soil horizons point to a glacial origin of soils and the link of forest-steppe grasslands to glacial forests. Siberian hemiboreal forests and related grasslands may be modern analogues of the reconstructed ecosystems, sharing many species with present day forest-steppe. We suggest that disturbances such as fire, herbivore grazing, and human activities have played an important role in shaping the forest-steppe over time, contributing to the formation of today’s richest grasslands.

Seed dispersal limitation causes negative legacy effect on restoration of grassland plant diversity on ski slopes.

Past forest use often has a long-term negative impact on the recovery of the original plant composition of semi-natural grasslands, which is known as a legacy effect. This study investigates the impact of seed dispersal limitations on the restoration of grassland plant diversity on ski slopes with past forest use, highlighting the negative legacy effect on biodiversity recovery. Focusing on ski areas, our research contrasts the vegetation on ski slopes originally created on semi-natural grasslands such as pasture (pasture slopes) and constructed by clearing secondary forests or conifer plantations (forest slopes). We examined species richness and diversity, considering seed dispersal modes, grassland management history, and seed source proximity. We reveal that the proximity to species-rich grassland sources is pivotal for the restoration of native grassland vegetation. Particularly, wind-dispersed species show significant recovery on slopes with sustained management for more than 70 years and those with neighboring species-rich grasslands, suggesting that both the duration of management and the proximity to seed sources are critical for overcoming the legacy effects of past forest use. Meanwhile, gravity-dispersed species failed to recover their richness and diversity regardless of both the duration of management and the proximity to seed source grasslands, which their diversity recovered where seed sources neighbored. Our findings emphasize the importance of considering seed dispersal limitation and management history in the restoration and conservation of grasslands and their biodiversity, particularly in landscapes experiencing past human intervention.

Species richness and dominant functional groups enhance aboveground biomass, with no effect on belowground biomass in Qinghai-Tibet Plateau's grasslands

Understanding the role of plant diversity in maintaining grassland ecosystem functioning is of great importance in ecological research. Despite decades of research, ecologists have struggled to understand the biodiversity-ecosystem functioning relationships and how the dominance of plant functional groups impacts ecosystem function. In attempting to understand (i) the temporal patterns of above- and below-ground biomass (AGB and BGB) and species richness, (ii) whether species richness is consistently associated with AGB and BGB, and (iii) the relative contributions of plant functional groups (forb, grass, legume, and sedge) in stabilizing ecosystem function, we used biomass productivity data of meadow steppe and alpine meadow in the Qinghai-Tibet Plateau (QTP) for the period 2015–2019. Our results show that AGB for both grasslands increased, but BGB stayed steady over 5 years. The rising tendency of AGB was caused by the upward trend of AGB in forbs and grasses, which are the dominant functional groups in QTP, stressing the importance of dominant functional groups to ecosystem functioning. The biodiversity-ecosystem functioning relationships were significantly positive for AGB, stable for BGB, and negative for the BGB:AGB ratio, which highlights the crucial role of higher species richness in ecosystem functioning. Significant differences in mean species richness among sites (9–19 species in meadow steppe and 8–22 species in alpine meadow) highlight the varying levels of species diversity across sites in the QTP. While 42% of the sites showed stable species richness, the reported increasing trends in species richness at 58% of the sites indicate the potential for ecological changes or processes in these areas. AGB in both grasslands increased, while BGB remained stable with increasing precipitation. The top soil layer (0–10 cm) dominated the observed BGB in both grasslands, as abundant nutrients in the top layer provide favorable conditions for root proliferation. In meadow steppe, AGB formed an isometric relationship with BGB, indicating that AGB increased with BGB. This study concludes that species richness influenced ecosystem functioning, and forbs and grasses dominated biomass productivity, of which the topsoil layer contributed three-quarters of BGB. Our study (i) provides empirical evidence of stable to increasing species richness in both grasslands over 5 years, and (ii) highlights the role of greater species richness in enhancing ecosystem functioning. These findings serve as a scientific reference for policymaking regarding ecosystem stability.

Prediction of species richness and diversity in sub‐alpine grasslands using satellite remote sensing and random forest machine‐learning algorithm

AbstractAimsRemote‐sensing approaches could be beneficial for monitoring and compiling essential biodiversity data because they are cost‐effective and allow for coverage of large areas over a short period. This study investigated the relationship between multispectral remote‐sensing data from Landsat 8 and Sentinel‐2 and species richness and diversity in mountainous and protected grasslands.LocationsGolden Gate Highlands National Park, Free State, South Africa.MethodsIn‐situ data of plant species composition and cover from 142 plots with 16 relevés each were distributed across the study site and used to calculate species richness and Shannon–Wiener species diversity index (species diversity). We used a machine‐learning random forest algorithm to optimize the prediction of species richness and diversity. The algorithm was used to identify the optimal spectral bands and vegetation indices for estimating species richness and diversity. Subsequently, the selected bands and vegetation indices were used to estimate species richness through random forest regression.ResultsThis research found weak relationships between remote‐sensing vegetation indices and the diversity metrics, but significant relationships were found between some spectral bands and diversity metrics. Moreover, using machine‐learning random forest, the multispectral data sets exhibited strong predictive powers. In this investigation, near‐infrared (NIR) seemed to be the most selected band for both sensors to explain species diversity in mountainous grasslands.Main conclusionsThis finding further ascertains the efficiency of optimizing high spatial resolution spectral information to estimate plant species richness and diversity. This research shows that NIR, Soil‐Adjusted Vegetation Index (SAVI) and Enhanced Vegetation Index (EVI) are the most adequate for predicting species richness and diversity in mountainous grasslands with relatively good accuracies. Plant phenology and the choice of sensor affect the relationship between spectral information and species diversity variables.

Precipitation variation: a key factor regulating plant diversity in semi-arid livestock grazing lands.

Livestock presence impacts plant biodiversity (species richness) in grassland ecosystems, yet extent and direction of grazing impacts on biodiversity vary greatly across inter-annual periods. In this study, an 8-year (2014-2021) grazing gradient experiment with sheep was conducted in a semi-arid grassland to investigate the impact of grazing under different precipitation variability on biodiversity. The results suggest no direct impact of grazing on species richness in semi-arid Stipa grassland. However, increased grazing indirectly enhanced species richness by elevating community dominance (increasing the sheltering effect of Stipa grass). Importantly, intensified grazing also regulates excessive community biomass resulting from increased inter-annual wetness (SPEI), amplifying the positive influence of annual humidity index on species richness. Lastly, we emphasize that, in water-constrained grassland ecosystems, intra-annual precipitation variability (PCI) was the most crucial factor driving species richness. Therefore, the water-heat synchrony during the growing season may alleviate physiological constraints on plants, significantly enhancing species richness as a result of multifactorial interactions. Our study provides strong evidence for how to regulate grazing intensity to increase biodiversity under future variable climate patterns. We suggest adapting grazing intensity according to local climate variability to achieve grassland biodiversity conservation.

Effects of management complexity on the composition, plant functional dominance relationships and physiognomy of high nature value grasslands

A significant proportion of Europe’s species-rich grasslands are semi-natural habitats. They have a long history of traditional management. Several studies have been carried out to conserve them, resulting in the establishment of subsidised conservation management schemes. On the other hand, many of these conservation management schemes have failed to provide locally adaptive solutions to maintain the diversity and functional status of species-rich grasslands. In addition, few studies have compared the conservation effectiveness of different levels of management complexity. The levels of management complexity in our study are based on how different management types (e.g. grazing and mowing etc.) and how different herbage removal intensities (e.g. lower and higher grazing intensities) are combined within and between years. To investigate this, we compared the overall effects of management complexity, herbage removal intensity and management type on plant diversity, plant functional type dominance relationships and plant physiognomy. Our field sampling was carried out in the sandy meso-xeric grasslands of the Turján Region of the Great Hungarian Plain (Central Hungary). We sampled nine 2 m × 2 m plots per grassland site (n = 12), recorded all the rooted plant species and estimated their percentage cover in each plot. High level of management complexity had significant positive effects on plant diversity, grazing had positive effects on plant diversity and phanerophyte density, while the studied levels of herbage removal intensity had no effect on diversity, plant functional types or plant physiognomy. In parallel, mowing and/or low levels of management complexity had some negative effects on conservation value (e.g. lower Shannon and Simpson diversity). In this landscape, the dominance of grazing and the more complex management is more optimal than relatively homogeneous mechanical mowing. The choice of management type and intensity is an important tool in the conservation management system of this landscape, but so too is its appropriate application in space and time. Through a detailed analysis of the effects of management complexity levels compared to management types and herbage removal intensity levels, we provide a new opportunity to make grassland management practices more effective for conserving biodiversity in this region, but it would be important to investigate these in different landscapes and conditions.

Towards more biodiverse agricultural landscapes: How to make species-rich grassland a desirable and feasible option for dairy farmers

Species-rich grasslands are promoted by public and private actors for reasons of biodiversity, landscape amenity and animal health. There is little understanding of the considerations of farmers when they opt for or against species-rich grasslands. We held a workshop with 20 farmers and conducted in-depth interviews with 15 livestock farmers in Alblasserwaard - Vijfheerenlanden, a peat meadow landscape in the West of the Netherlands. In these discussions we made an inventory of opportunities and barriers that the farmers experience in terms of willingness, ability and support from society. In our analysis we distinguished four farming styles accommodating species-rich grasslands, which differ in the way willingness, ability and support from society are experienced by the farmers. Based on these findings, we make generic and farming style-specific recommendations for public policy and parties in the supply chain for effectively promoting species-rich grasslands among livestock farmers. We propose that a diverse public-private policy mix is essential to reach as many farmers as possible, acknowledging their heterogeneity and addressing their multiple needs.

Maintaining an open landscape: Comparison of management methods for semi-natural grasslands: A Swedish multi-site study

Traditional management of semi-natural grasslands by grazing or annual mowing is not always feasible and the current study set out to evaluate alternative management methods. At eleven locations in southern Sweden, block experiments were conducted evaluating seven treatments in 5 m*20 m plots: grazing, annual mowing, annual spring burning, mowing every third year, mechanical removal of woody plants, herbicide control of woody plants, and untreated control. After approximately 13 years, trends for woody plants and species richness, and the occurrence of management-dependent plant species, low-grown species, and pollinator-attracting plant species were analysed. Overall, the annual mowing and grazing treatments resulted in fewer woody plants, the highest species richness, and more management-dependent, low-grown, and pollinator-attracting species. The untreated control plots showed the opposite effect, whereas less intense management (annual burning, mowing every third year, and mechanical and chemical treatments of woody plants) showed mixed and often intermediate effects. Compared to grazing and mowing, less intense management methods do not constitute long-term management alternatives to preserve typical features of species-rich grasslands. However, they may be short-term alternatives at sites where the recruitment of woody species is absent or rare. However, to prevent the encroachment of woody species, less intensive management might be a better long-term alternative at more productive sites with slow or inhibited woody species recruitment.

Significant decline in habitat specialists in semi-dry grasslands over four decades

Semi-dry grasslands are among the most species-rich plant communities in the world, harbouring many specialised and threatened species. Most of these grasslands were traditionally maintained by grazing and hay-making. After traditional management ended, protected areas were established and conservation management was introduced to protect the most valuable grassland sites. However, recent changes in land use, eutrophication and climate warming are negatively impacting the biodiversity of these grasslands. In 2022, we resurveyed historical vegetation plots in the Central Moravian Carpathians (Czech Republic), first sampled in the 1980s, to test whether the plant species composition and richness of semi-dry grasslands are changing over time and, if so, whether the decline in habitat quality and plant diversity is absent or less severe in protected areas. We found significant changes in species composition. Species richness and the proportion of habitat specialists and Red-List species decreased, whereas competitively stronger species with higher moisture and nutrient requirements increased. These trends were more pronounced outside the protected areas but also occurred within protected areas. The main factor behind these changes appears to be the cessation of traditional management and natural succession supported by eutrophication.

Contrasting responses of two typical plant communities to precipitation variability in horqin sandy land, northeast China

The ongoing modification of precipitation regime highlights the necessity to further investigate underlying vegetation processes. To figure out the key precipitation characteristics that largely affected the biomass and species richness of different plant functional groups in the semiarid sandy land, we compared the 15-year (from 2005 to 2019) variation in the aboveground biomass (AGB), precipitation use efficiency (PUE) and species richness of two typical biotopes (fixed dune and sandy grassland) in Horqin Sandy Land, a semiarid sandy land in northeast China. Results showed that the sandy grassland had higher AGB and PUE, lower species richness than the fixed dune; the annuals contributed 60.16% of the AGB and 60.32% of the species richness in sandy grassland, while contributed 53.40% and 75.77% in fixed dune, respectively; the AGB and species richness in the fixed dune had medium positive correlation with annual precipitation, while that in the sandy grassland had medium positive correlation with the total amount of specific rainfall events in the growing season (e.g. cumulative precipitation of 10–40 mm rain events and number of ≥ 10 mm rain event). There was no significant correlations were detected between PUE and annual precipitation, and weakly positive correlations were detected between PUE and amount and number of medium rainfall events in growing season. Our results suggested that the biomes dominated by annual plants were more responsive to the variability of growing season rainfall pattern rather than annual precipitation. In semiarid sandy grassland communities, the frequent medium rainfall events (5–50 mm) have significant role on the biomass, and the high species richness is likely to depend on the number of larger ones (≥ 10 mm). The AGB and species richness of grassland communities in semi-arid sandy land was the result of the combined effect of amount size, number and interval of rain event.

Plant Community and Soil Properties Regulate Space-Scale Dependence of Species Diversity under Grazing Exclusion and Rest Grazing in the Qilian Mountains of China

Grazing exclusion (GE) and rest grazing (RG) are important management systems for the restoration of degraded grassland ecosystems. In order to evaluate the effects and mechanisms of different grazing management systems on the scale dependency of species diversity, plant community indices and soil variables were determined in 32 plots in the Qilian Mountains in Gansu Province. The results show that diversity effects and their regulating mechanisms had space-scale dependence under different grazing management systems. The species richness and species diversity indices of RG grassland were significantly higher than those of GE at the regional scale. Species richness for RG and GE plots was 128 and 98, respectively, and the Shannon–Wiener and Simpson indices for RG and GE plots were 2.26 and 2.16, and 0.85 and 0.83, respectively. Additionally, three grazing management systems had a significant effect on species richness in mountain meadows, but different management systems had significantly different effects on species diversity indices in mountain meadows and temperate steppes. Meanwhile, soil variables only influenced species diversity at the regional scale. Most of the plant and soil variables at each scale had positive effects on species diversity. However, a negative correlation was seen between biodiversity and species coverage, mean plant height, soil porosity (SP) and bulk density (BD) under the two contrasting grazing management systems. In conclusion, choosing RG at the regional scale and selecting grazing management systems according to different grassland types at the local scale can help to restore degraded grassland vegetation.

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.

Using the old-growth concept to identify old species-rich semi-natural grasslands

The concept of ‘old growth’, originally developed for forests, was recently extended to grassland to distinguish old natural grasslands (NG) from semi-natural grassland (SNG). Comparing mesophile SNGs of different ages, we show that the concept is also able to distinguish old SNGs from young SNGs and also that assembly time plays a determining role in the ecology and evolution of SNG. As expected from the old-growth concept and like NG, old SNGs have an unique floristic composition with a higher greater proportion of long-lived species with underground storage, clonal growth organs and bud banks, higher species richness, diversity and evenness. Furthermore, they have much greater floral abundances and contain sedge species not found in younger SNGs such as Carex caryophyllea which is a reliable indicator of old unimproved species-rich grasslands. Comparison with other old grassland systems suggests that the old SNGs are probably remnants of the rich biodiversity of the grassland vegetation that was once widespread in the Atlantic biogeographic region. Given their ecological, cultural and aesthetic values and their role in essential ecosystem services, these threatened old SNGs deserve urgent protection.

Grassland restoration with plant material transfer – bridging the knowledge gap between science and practice

In Central Europe, species-rich grasslands have strongly diminished over the last century. The transfer of seed-containing plant material from donor sites with a desired species composition to restoration sites is a well-established method to restore species-rich grasslands. Despite a plethora of available literature, restoration projects with plant material transfer often fail or do not reach the planned goals. Practitioners’ knowledge is a highly important but underexplored source of information on factors deciding about success of restoration projects. At the same time, it is unclear to which degree scientific findings on success factors are known and considered by practitioners, and if science actually investigates the most relevant aspects for practice. To bridge the gap between practitioners’ knowledge and restoration science, we conducted semi-structured interviews with 33 practitioners involved in plant material transfer projects. Using qualitative content analysis, we analysed the interviews for success factors, and compared them to success factors of plant material transfer as investigated in peer-reviewed European studies on the method. We found that science investigated a broad range of practical, technical, and ecological success factors, and that practitioners were generally well aware of this evidence, trying to make use of the knowledge. Failure of practitioners’ projects often resulted from organizational obstacles, which were founded in lacking trust and low experience levels among the involved people. We advise unexperienced practitioners to involve more experienced practitioners in their projects if possible. Furthermore, we emphasize the importance of identifying relevant local stakeholders and building trustful regional networks. Interdisciplinary scientific studies considering success factors beyond practical and ecological aspects are required to support widespread effective grassland restoration with plant material transfer.