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We selected 15 sheep‐grazed sand pastures along a gradient of increasing grazing intensity to study the fine‐scale patterns of main biomass fractions (green biomass, litter) and that of plant species and functional groups (life forms and social behaviour types). We classified them into five grazing intensity levels based on stocking density, proximity to drinking and resting places and the number of faeces. We aimed to answer the following questions: (i) How does increasing intensity of sheep grazing affect the amount of green biomass, the species richness and their relationship in sand pastures? (ii) How does increasing intensity of sheep grazing affect the biomass of perennial and short‐lived graminoids and forbs? (iii) How does the disturbance value—expressed in the biomass ratio of disturbance‐tolerant and ruderal species—change along the gradient of grazing intensity? A unimodal relationship between green biomass and species richness was detected; however, the ordination (canonical correspondence analysis, CCA) showed no clustering of pastures subjected to the same levels of grazing intensity. Along the grazing intensity gradient we found an increasing trend in species richness and significant differences in green biomass (decreasing trend), litter (decreasing trend), graminoids (decreasing trend) and short‐lived forbs (increasing trend). We found an increasing amount of disturbance‐tolerant and ruderal species with increasing grazing intensity. We suggest that we might need to use multiple scales for sampling and a fine‐scale assessment of grazing intensity. Our findings might be instructive for pastures in densely populated regions, which are prone to the encroachment of disturbance‐tolerant and ruderal species. [ABSTRACT FROM AUTHOR]

Ecosystems with forest and grassland patches as alternative stable states usually contain various closed, semi‐open and open habitats, which may be aligned along a vegetation cover gradient. Taxonomic diversity usually peaks near the middle of the gradient, but our knowledge on functional and phylogenetic diversity trends along gradients is more limited.We investigated the eight main habitats of Hungarian forest‐grassland mosaics, representing various vegetation cover values, and compared their species composition as well as their taxonomic, functional and phylogenetic diversity.We found a compositional gradient ranging from large forest patches through smaller‐sized forest patches and edges to closed and open grasslands. Species richness peaked at the middle of the gradient (at edges). Shannon diversity was high near the middle and at the open end of the gradient. Functional diversity was high throughout woody habitats (in forests and at edges) and was significantly lower in grasslands. When considering all species, phylogenetic diversity tended to peak at north‐facing forest edges. When excluding non‐angiosperms, this peak disappeared.The high taxonomic diversity at the middle of the gradient is in line with the edge‐effect theory. Our results suggest that community assembly in grasslands may be dominated by environmental filtering, while competition may be decisive in woody habitats. The low phylogenetic diversity of grassland habitats can be explained by their young evolutionary age compared to forests.Synthesis. Functional and phylogenetic diversity do not necessarily coincide with taxonomic diversity along vegetation cover gradients. In ecosystems where forest and grassland patches represent alternative stable states, the trends of taxonomic diversity may be similar to those revealed here, but functional diversity patterns may be more system‐specific for some traits. Trends in phylogenetic diversity may vary according to the evolutionary age of the habitats. [ABSTRACT FROM AUTHOR]

Aim: We evaluated stands of the invasive grass, Sporobolus cryptandrus in its native North American range and its non-native European range, where it is a recent invader. Our aim was to reveal how the species’ increasing abundance affects functional diversity and the ecosystem service-provisioning capacities of plant communities in both ranges. Location: Sand grasslands in the Kiskunság, Hungary and in Montana, USA. Methods: All vascular plant species and their relative abundances were recorded in a stratified random manner in 1 m × 1 m plots in each range, using the following cover categories of Sporobolus as strata: 1%–25%, 26%–50%, 50%–75%, and 75%–100%. The functional characteristics of the plant communities in the two continents were compared. We performed comparisons of the communities both with and without including Sporobolus. Results: Increasing Sporobolus cover resulted in a lower functional diversity and species richness, reduced average specific leaf area and increased the height of whole plant communities in both ranges but these effects were significantly stronger in the non-native stands. Sporobolus also negatively affected the cover of insect-pollinated plant species and the proportion of native perennials, switching the rest of the community from perennial-dominated to annual-dominated. In plant communities without Sporobolus, increasing Sporobolus cover led to a higher specific leaf area and seed mass in both ranges, but average height was decreasing along the Sporobolus abundance gradient in the native range, whereas it was increasing in the non-native range. Conclusions: The spread of Sporobolus, away from its native range, leads to the impoverishment of host communities and compromises the biomass and floral resourceprovisioning capacity of the vegetation to higher trophic levels. Tackling the spread of this new invader should therefore be a priority task. [ABSTRACT FROM AUTHOR]

Aim: In Australia, natural grasslands largely occur on fertile clay soils and have consequently been extensively cultivated since European settlement. Other studies have demonstrated that passive restoration of subtropical grassland is possible in environments where there is substantial native remnant vegetation in the surrounding landscape. This study examined a chronosequence of abandoned fields to investigate the recovery of fragmented grassland in a matrix of cultivated land with significant exotic species that may impede succession. Location: Darling Downs, Queensland, Australia. Methods: In this study we surveyed a chronosequence of ex‐cultivated subtropical grasslands in Queensland's Darling Downs, where only 1% of the original grasslands remain. Floristic surveys were carried out in 80 fallow sites up to 51 years old, and data were compared with 16 previously surveyed remnant grasslands on the same land type. Results: Richness of native species increased with time since cultivation and approached, but did not reach, that of remnant grasslands after 51 years, whereas the richness of exotics declined with time since cultivation. Rainfall and grazing positively and negatively affected exotic plant abundance respectively and these factors had no significant direct or indirect effect on the native species richness. In terms of composition, fallow grasslands supported 54% of the native plant species from remnant grasslands after 51 years. The native perennial grasses Dichanthium sericeum and Aristida leptopoda were the only dominant species in the remnants that were present in more than 60% of the fallow grasslands. Of the species from remnants that were "missing" from fallow sites, most were native perennial forbs and grasses. Compositional dissimilarity of fallow grassland to remnant grasslands remained high after 51 years (78%). Grassland species that are uncommon in nearby hill woodlands were preferentially absent in fallow grassland and this partly explains the slow compositional recovery. Conclusion: In a highly fragmented landscape, passive restoration is only partially effective. The restoration of grassland is probably enhanced by repositories of native seeds from hill woodlands that are too rocky to cultivate. However, some species may have to be actively reintroduced to achieve complete recovery. In this landscape, where grazing is a dominant land use, exotic species do not seem to impede succession. [ABSTRACT FROM AUTHOR]

Questions: Which are the effects of inter‐annual meteorological fluctuations on plant species richness and vegetation dynamics in Mediterranean temporary ponds, shallow wetlands characterized by alternating phases of drought and flooding? Which are the effects of wild boar disturbance? How do the responses of specialist or non‐specialist species of the habitat differ? Location: NW Sardinia Island (Italy). Methods: We assessed plant cover during six years within one 60 cm × 60 cm quadrat in each of five areas. To measure the effect of inter‐annual meteorological fluctuations on vegetation, we used two indices: the evapotranspiration and the synthetic agrometeorological indicator. To quantify the effect of disturbance by boars, we compared two treatments: disturbed and non‐disturbed (located outside and inside 1.5 m × 1.5 m exclosures respectively). As a whole, we monitored 60 plots (6 years × 2 treatments × 5 replications). We analyzed data using ANOVA, PERMANOVA and BIO‐ENV. Results: Plant species richness and composition showed significant differences between years and treatments. Species composition was correlated with the evapotranspiration before the vegetative peak during the last period and with the agrometeorological indicator during the whole vegetative period. Specialist species showed much weaker growth, quantified as cover, in the drier years. Starting from the third survey year, plant richness and cover of specialist species were significantly higher in disturbed than in not‐disturbed plots. The extent of bare soil generally was not affected by the treatment. Conclusions: Meteorological fluctuations affect plant species composition and vegetation dynamics in Mediterranean temporary ponds. The sensitivity of specialist species could make them particularly vulnerable to climate change. Nevertheless, they are resilient to unpredictable disturbances such as burrowing by wild boar. However, our results concerning the positive impact of wild boar disturbance on the vegetation cannot be generalized. Elsewhere, the lack of hunting activity could also be a problem for these habitats. [ABSTRACT FROM AUTHOR]

Questions: How are dispersal processes, abiotic and biotic interactions determining the initial salt marsh plant community establishment and development when connectivity is different? We aim to answer this question by analysing the spatial and temporal patterns of plant establishment along an environmental gradient at two connectivity settings. Location: Back‐barrier salt marsh and tidal flats of Spiekeroog, northwest Germany. Methods: We established an experiment along a saltmarsh elevation gradient with bare sediment open for spontaneous colonisation on the natural salt marsh and on the experimental salt marsh islands built on the tidal flats approximately 500 m from the natural salt marsh for low connectivity. Plant establishment was identified from georeferenced photos at least monthly. Results: Experimental islands as low‐connectivity plots had limited colonisation by annual halophytes that produced large number of small seeds. Number of individuals increased with higher connectivity at patches enclosed by salt marsh. Number of individuals was highest at the mid elevations whereas peak species richness was at the upper salt marsh. Temporal patterns of seedling emergence showed increasing plant numbers until the end of April followed by a gradual decline over the season at the pioneer and lower salt marsh zones. Upper elevations on the other hand had a stable number of low individual counts over time. Spatial clustering of plant individuals indicating possible facilitation was important at the initial stages of salt marsh development at pioneer and lower salt marsh elevation, but only early in the season. Conclusions: Stochastic patterns of early salt marsh colonisation indicated that success of species colonisation was determined by seed properties, seed availability and environmental conditions mediated by elevation. We found indications that at the initial stages, further colonisation was supported by already colonised plants but shifted to avoidance later in the season. [ABSTRACT FROM AUTHOR]

Questions: Vegetative re‐sprouting and recruitment from seed determine grassland recovery after severe drought, but the mechanisms determining vegetation composition are not fully understood. We ask how the timing of drought and seed availability modify the drought legacy effects on composition and function in a temperate, semi‐natural grassland. Location: Negrentino, southern Alps, Switzerland. Methods: Under automated rainout shelters, we simulated extreme seasonal drought events in a late summer and in the following spring, added rainwater to simulate normal conditions in no‐drought controls and maintained haymaking at times of normal practice. Towards the end of the summer drought, we added seeds of ten local species in a three‐factor split‐plot arrangement with seven blocks as the replicated unit. We measured fine‐scale variation in soil depth. We assessed the biomass of graminoids and forbs at regular harvesting dates and the species frequencies of established plants and recruits before treatment start, repeating these assessments for three years thereafter. We measured the biomass proportions of post‐drought annual recruit cohorts in year 4 after drought. Results: One‐time seed addition augmented recruits, modified species composition and enhanced species diversity; these effects propagated to increased reproductive shoots of recruits and community biomass four years later. Single and repeated seasonal droughts only caused low adult plant mortality but clearly reduced recruitment from seed, while post‐drought establishment was slightly enhanced. Seed augmentation compensated the negative spring drought effect on forb recruits and in turn mitigated the negative impact of drought on species diversity after drought. Conclusions: Our experiment shows that seed deficiency limits productivity and that seed deficiency compensation can help to stabilize diversity and productivity in semi‐natural grassland. Releasing the current constraints of management on seed supply in grassland would therefore assist in mitigating negative drought impacts. [ABSTRACT FROM AUTHOR]

Questions: Woody encroachment affects many open habitats from semi‐deserts to wetlands and grasslands. We aimed to study the effect of native woody encroachment on grassland plant biodiversity in loess steppe fragments by analysing the vegetation composition of grasslands subjected to increasing levels of encroachment. We studied both ancient and restored grasslands with the following research hypotheses: (a) increasing woody encroachment decreases total diversity and the species richness of dry‐grassland species; and (b) the effect of woody cover on grassland biodiversity differs between ancient and restored grasslands. Location: South‐Eastern part of Transdanubia, Hungary, Central Europe. Methods: Altogether 63 loess grassland fragments were selected for the study. The percentage cover of trees, shrubs and herbaceous vegetation were recorded in 400‐m2‐sized plots (n = 110). The effects of woody encroachment and grassland age on diversity, total species richness of the herb layer, and richness of dry‐grassland species were analysed. Results: We found that woody encroachment affected the total richness of the herb layer and the species richness of dry‐grassland species. For most of the listed variables, lowest values were found for the highest woody encroachment groups. Grassland age affected the species richness of the herb layer and that of dry‐grassland species; lower values were detected in restored grasslands. In restored grasslands, Shannon diversity and species evenness were lower, while Berger–Parker dominance was higher than in ancient grasslands. Species composition and richness displayed a relatively high resistance to moderate woody encroachment; the highest decrease in diversity was detected at a high level of woody encroachment (>52% of woody cover). Conclusions: We can conclude that low to moderate woody encroachment cannot be simplistically regarded as degradation. Results suggest that moderately encroached loess grasslands can be easily restored by the suppression of woody species, as their species pool still contains many dry‐grassland species targeted for restoration. [ABSTRACT FROM AUTHOR]

Plant species performance in rangelands highly depends on the effect of grazing and also on the occurrence of unpalatable benefactor species that can act as biotic refuges protecting neighboring plants from herbivores. The balance between facilitation and competition may changes with the benefactor density. Despite the high number of studies on the role of biotic refuges, the density dependent effects of unpalatable herbaceous plants on the performance of other species, and on the habitat heterogeneity of rangelands are still unclear. Therefore, we performed a study to test the following hypotheses: (i) Performances of understory species follow a humped-back relationship along the density gradient of the unpalatable benefactor species. (ii) Small-scale heterogeneity of the vegetation decreases with increasing benefactor density. We studied meadow steppes with medium intensity cattle grazing in Hungary. We surveyed understory species' performance (number of flowering shoots and cover scores) along the density gradient of a common, native unpalatable species (Althaea officinalis). Our findings supported both hypotheses. We found unimodal relationship between the benefactor cover and both the flowering success and richness of understory species. Moreover, small-scale heterogeneity declined with increasing benefactor cover. In this study we detected a humped-back pattern of facilitation along the density gradient of an herbaceous benefactor in pastures. Indeed, this pattern was predictable based on such conceptual models like "consumer pressure-abiotic stress model," "humped-back model," "intermediate disturbance hypothesis," and "disturbance heterogeneity model"; but until now the validity of these relationships has not been demonstrated for herbaceous species. By the demonstration of this effect between herbaceous species we can better forecast the responses of grasslands to changes in management. [ABSTRACT FROM AUTHOR]

Restoration of grasslands on abandoned croplands is a major opportunity for land development in degraded landscapes. In this study, we compared the success of three restoration measures, spontaneous recovery, perennial‐crop–mediated restoration, and sowing native grasses, by using a unique combination of species‐based and trait‐based approaches. We sampled 373 4‐m2 plots in nearly 1,000 ha of 20‐year‐old–restored grasslands and 72 4‐m2 plots in three neighbouring ancient grasslands. Species richness and target species cover were higher in spontaneously recovered sites than in other restored sites, but reference sites had higher scores than all restored sites. Spontaneous sites had higher functional diversity than the other restored sites. Spontaneous and reference sites showed little difference in their functional diversity and in the community‐weighted means of relevant traits. Our findings indicate that the establishment limitation effect of the initial application of perennial crops or sowing competitive grasses can last for decades, hindering the recolonization of target species and the recovery of functional diversity; thus, they should be applied in landscapes with high cover of natural habitats only when inhibiting undesirable species is of paramount importance. The similar levels of functional niche saturation in spontaneous and reference sites may also indicate a self‐developed establishment‐limited situation after 20 years of succession. In combination with this, the lagging recovery of species richness entails lower functional redundancy in spontaneous sites. Our results underline the necessity of postrestorative management methods that reduce establishment limitation and contribute to the recolonization and subsequent coexistence of functionally similar species. [ABSTRACT FROM AUTHOR]

Abstract: In intensively used landscapes, remnant grassland fragments are often restricted to places unsuitable for agricultural cultivation. Such refuges are the ancient burial mounds called “kurgans,” which are typical landscape elements of the Eurasian steppe and forest steppe zone. Due to their hill‐like shape, loose soil structure and undisturbed status kurgans provide proper habitats for burrowing mammals. Accordingly, grassland vegetation on kurgans is often exposed to bioturbation, which can influence the habitat structure and plant species pool. In our study, we explored the effect of fox burrows and landscape context on the habitat properties and vegetation composition of small landscape elements, using kurgans as model habitats. We surveyed the vegetation of fox burrows and that of the surrounding grassland on five kurgans situated in cleared landscapes surrounded by arable lands and five kurgans in complex landscapes surrounded by grazed grasslands. We recorded the percentage cover of vascular plants, the amount of litter, and soil moisture content in twelve 0.5 m × 0.5 m plots per kurgan, in a total of 120 plots. We found that foxes considerably transformed habitat conditions and created microhabitats by changing the soil nutrient availability and reducing total vegetation cover and litter. Several grassland specialist species, mostly grasses (Agropyron cristatum, Elymus hispidus, and Stipa capillata) established in the newly created microhabitats, although the cover of noxious species was also considerable. We found that landscape context influenced the sort of species which could establish on kurgans by affecting the available species pool and soil moisture. Our results revealed that foxes act as ecosystem engineers on kurgans by transforming abiotic and biotic conditions by burrowing. Their engineering activity maintains disturbance‐dependent components of dry grasslands and increases local environmental heterogeneity. [ABSTRACT FROM AUTHOR]

Context: Landscape and habitat filters are major drivers of biodiversity of small habitat islands by influencing dispersal and extinction events in plant metapopulations.Objectives: We assessed the effects of landscape and habitat filters on the species richness, abundance and trait composition of grassland specialist and generalist plants in small habitat islands. We studied traits related to functional spatial connectivity (dispersal ability by wind and animals) and temporal connectivity (clonality and seed bank persistence) using model selection.Methods: We sampled herbaceous plants, landscape (local and regional isolation) and habitat filters (inclination, woody encroachment and disturbance) in 82 grassland islands in Hungary.Results: Isolation decreased the abundance of good disperser specialist plants due to the lack of directional vectors transferring seeds between suitable habitat patches. Clonality was an effective strategy, but persistent seed bank did not support the survival of specialist plants in isolated habitats. Generalist plants were unaffected by landscape filters due to their wide habitat breadth and high propagule availability. Clonal specialist plants could cope with increasing woody encroachment due to their high resistance against environmental changes; however, they could not cope with intensive disturbance. Steep slopes providing environmental heterogeneity had an overall positive effect on species richness.Conclusions: Specialist plants were influenced by the interplay of landscape filters influencing their abundance and habitat filters affecting species richness. Landscape filtering by isolation influenced the abundance of specialist plants by regulating seed dispersal. Habitat filters sorted species that could establish and persist at a site by influencing microsite availability and quality. [ABSTRACT FROM AUTHOR]

• Water blooms caused by Cyanobacteria have become more and more frequent. • We assessed the effect of blooms on diversity in hypertrophic shallow lakes. • The species diversity of non-cyanobacteria was not affected negatively by the bloom. • The functional richness and dispersion were only marginally significantly affected. • Applied methods are not sensitive to reflect the diversity of subordinated species. Under increasing pressure of climatic change and anthropogenic eutrophication, water blooms, i.e. the formation of high phytoplankton biomass of a single or a few species, have become more and more frequent in lake ecosystems that is caused mostly by Cyanobacteria. The dynamics of phytoplankton under a cyanobacterial pressure may provide important information about what a competitive advantage of Cyanobacteria have over eukaryotic microalgae. The research, therefore focused on the relationship between cyanobacterial blooms and the accompanying species in hypertrophic shallow lakes where nutrients are in excess. The following hypotheses were selected for testing: i) Cyanobacterial blooms negatively affect the species richness and diversity of phytoplankton assemblages in the studied hypertrophic lakes. ii) Cyanobacterial blooms negatively affect the multi-trait functional diversity of phytoplankton assemblages in the studied hypertrophic lakes. iii) The formation of a cyanobacterial bloom causes a shift in the species and trait composition of phytoplankton assemblages. It was found that the species diversity of non-cyanobacterial assemblages was not affected negatively by increasing density of Cyanobacteria. Cyanobacterial biomass negatively affected the functional richness and functional dispersion of the assemblages, but both relationships were only marginally significant. Some temporal shift was detected in the community weighted mean values of width, colonial ability of accompanying microalgae, and also in flagellatedness and mixotrophic ability. We conclude that Cyanobacterial blooms basically alter dominance relations in the phytoplankton and reduce availability of light in waters. However, it does not necessarily coincide with the elimination of other taxa and reduction their species numbers or diversity. The formerly published data on the decrease in species richness can be likely explained by methodological deficiencies, which are responsible for reduced detectability of species. To better understand the seasonal dynamics and resilience of phytoplankton assemblages in hypertrophic water bodies the development of new methodologies by which diversity and succession of subordinate species can be evaluated is required. [ABSTRACT FROM AUTHOR]

Grasslands used to be vital landscape elements throughout Europe. Nowadays, the area of grasslands is dramatically reduced, especially in industrial countries. Grassland restoration is widely applied to increase the naturalness of the landscape and preserve biodiversity. We reviewed the most frequently used restoration techniques (spontaneous succession, sowing seed mixtures, transfer of plant material, topsoil removal and transfer) and techniques used to improve species richness (planting, grazing and mowing) to recover natural-like grasslands from ex-arable lands. We focus on the usefulness of methods in restoring biodiversity, their practical feasibility and costs. We conclude that the success of each technique depends on the site conditions, history, availability of propagules and/or donor sites, and on the budget and time available for restoration. Spontaneous succession can be an option for restoration when no rapid result is expected, and is likely to lead to the target in areas with high availability of propagules. Sowing low-diversity seed mixtures is recommended when we aim at to create basic grassland vegetation in large areas and/or in a short time. The compilation of high-diversity seed mixtures for large sites is rather difficult and expensive; thus, it may be applied rather on smaller areas. We recommend combining the two kinds of seed sowing methods by sowing low-diversity mixtures in a large area and high-diversity mixtures in small blocks to create species-rich source patches for the spontaneous colonization of nearby areas. When proper local hay sources are available, the restoration with plant material transfer can be a fast and effective method for restoration. [ABSTRACT FROM AUTHOR]

Abstract: We studied the effect of sowing low-diversity seed mixtures (containing 2–3 competitive grass species) on the regeneration of vegetation on croplands previously used as alfalfa fields. In four permanent plots in 10 restored fields (four with alkali and six with loess seed mixture) the cover of flowering plants was recorded and phytomass was measured between 2006 and 2008. We asked three questions: (i) How fast will weedy, short-lived species decrease in abundance during secondary succession enhanced by sowing low-diversity seed mixtures? (ii) Can weeds be suppressed by sowing competitive native grasses, followed up by management by mowing? (iii) Can succession towards the target native grasslands be accelerated by sowing only low-diversity seed mixtures compared to set-aside old field succession? Our results showed that in just two years a vegetation dominated by perennial grasses has developed, which successfully prevented the establishment of weed species. These results suggested that sowing seeds of two or three competitive grass species is an effective tool to eliminate weed domination and to lead towards the restoration of species poor grasslands with grass domination such as alkali grasslands. However, the developed dense perennial grass cover and the accumulated litter may hamper the immigration of specialist species characteristic to reference grasslands. Therefore, the restoration of species-rich grasslands requires the facilitation of the immigration of grassland specialist species by further management (grazing, mowing and/or hay-transport). [Copyright &y& Elsevier]

Highlights: [•] The paper deals with natural, semi-natural and improved Palaearctic grasslands. [•] High species richness at plot-scale occurs in semi-dry basiphilous grasslands. [•] Palaearctic grasslands have a big species pool including many threatened biota. [•] Semi-natural grasslands are threatened by intensification and abandonment. [•] Natural steppes have largely been converted to arable land. [ABSTRACT FROM AUTHOR]