In biodiversity conservation of agriculture‐driven landscapes, grasslands have an outstanding importance; their conservation became a top priority both in research and practice. In many regions, sheep or cattle grazing are the best options for biodiversity conservation. In our study, we compared the effects of cattle and sheep grazing on short‐grass steppe vegetation under various grazing intensities. We tested the following study hypotheses: (i) sheep grazing maintains a lower taxonomic and functional diversity, lower amount of forbs compared with cattle grazing; and (ii) the effects of grazing are highly intensity dependent: the differences detected between cattle and sheep grazing are more pronounced at low grazing intensities than at high ones, because the selectivity of grazing decreases at higher intensities. We found lower taxonomic and functional diversity, and lower cover of forbs in sheep‐grazed steppes compared with cattle‐grazed ones. Grazing intensity had a significant effect only on species richness, while on Shannon diversity and evenness, only livestock type had a significant effect. While most single trait indices were affected by the type of the grazer, significant effect of intensity was detected only in few cases. These findings indicated that the selection of the livestock type is the most crucial in conservation; however, for proper ecosystem functioning and high trait variability, the suitable grazing intensity should also be carefully adjusted. Copyright © 2016 John Wiley & Sons, Ltd.

Question Explaining the biomass–species richness relationship is key to understanding vegetation dynamics. Several possible mechanisms have been suggested, but complex analysis of plant strategies, major biomass and species richness components along a long productivity gradient is still lacking. We provide a detailed analysis of the relationship between major biomass components (total above‐ground biomass, green biomass and litter), plant strategies and species richness along a long gradient of alkali and loess grasslands in a steppe landscape in Central Europe. Location Hortobágy, Great Hungarian Plain, East Hungary. Methods Above‐ground biomass of characteristic alkali and loess grassland stands was sampled along a gradient of increasing productivity. In each grassland stand, a 25‐m2 sample site was randomly selected. Within each site, ten above‐ground biomass samples (20 × 20 cm) were collected randomly in June 2009, at the peak of biomass production. We classified all species into mixed C‐S‐R strategy types. To obtain correlations between various biomass and species richness data, Spearman rank correlation was used. The relationship between plant strategies and species composition were displayed with a DCA ordination. Results The frequently detected humped‐back relationship was valid for the relation of total biomass and species richness. With increasing amount of total biomass, we detected an increasing proportion of competitors, and a decreasing proportion of stress tolerators in green biomass. A low proportion of ruderals was detected at both low and high biomass levels. Species richness was affected positively by litter at low litter scores, but there was a negative litter effect from much lower scores than detected previously (from 400 g·m−2). There was a positive relationship between green biomass production and species richness. Conclusions The study revealed that at the initial part of a productivity gradient, stress is likely responsible for low species richness. Our results show that litter can shape changes in species richness along the whole biomass gradient, thus the litter effect is one of the major mechanisms structuring grassland diversity.

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Question: Based on the spontaneous vegetation development of old-fields in the Ny ırs eg and Kiskuns ag sand regions (Hungary), we aimed to answer the following questions using the chronosequence method: (1) how do the proportions of different functional groups change during succession;(2) which target species establish successfully in the old-fields during the course of succession; and (3) how successful is spontaneous succession in the recovery of target grasslands?Location: Two sand regions of the Great Hungarian Plain: (1) the Ny ırs eg sand region (East Hungary, acidic sand, moderately continental climate) and the Kiskuns ag (Central Hungary, calcareous sand, continental climate). Methods:Altogether 24 old-fields were classified into young (<10-yr-old), middle-aged (10-20-yr-old) and late-succession (20-40-yr-old) old-fields; four fields in each age category. For baseline vegetation reference, three open and three closed sand grassland stands in both regions were sampled in the vicinity of the old-fields. The percentage cover of vascular plants was recorded in five 2 9 2-m plots in each field, in early May and late June 2012. We used life forms, clonal spreading traits and Ellenberg indicator values for nutrients in the analysis. Species of Festuco-Brometea class were considered as target species.Results: The cover of hemicryptophytes and geophytes increased, the cover of short-lived species decreased with time. Cover of species without clonal spreading ability decreased, while cover of species with clonal spreading ability increased with increasing field age. The cover of invasive species decreased with increasing field age. The majority of target species had established already in the young and middle-aged old-fields, although their cover was significantly higher in the two older age groups.Conclusion: Spontaneous succession can be a vital option in recovery of sand grassland vegetation in Central Europe; the majority of the species pool of sandy grasslands can be recovered in the first 10-20 yrs. However, the success of grassland recovery can be strongly influenced by the surrounding species pool and can be slow if seed dispersal is limited. Spontaneous succession is most promising when the target species of grasslands immigrate at the very beginning of the succession, within the first few years.

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Questions Common milkweed (Asclepias syriaca L.) is an invasive ‘super species’ that has invaded extensive areas in Europe, forming novel ecosystems. One study has reported neutral effects of common milkweed on the native flora of sand dune grasslands in Hungary after the removal of invasive pine plantation. However, the effects of common milkweed on native flora more generally are unknown. Focusing on the potential effect of milkweed, we tested the following hypotheses: (1) the cover of native grassland species decreases with increasing cover of common milkweed; and (2) native species with low specific leaf area (SLA), height, seed mass and clonal spreading ability (i.e. low competitive ability) are more likely suppressed by milkweed compared with natives with high competitive ability. Location Late successional sandy old‐fields invaded by milkweed in the Great Hungarian Plain (Kiskunság, central Hungary). Methods We recorded the cover of vascular plants in seven old‐fields; in each old‐field we sampled 12 plots including plots with different milkweed cover and control plots without milkweed. We used linear mixed effect models for exploring the effects of milkweed on the species richness and cover of native grassland species. To identify the common traits of the most affected native species, we used trait‐based analyses; we studied leaf–height–seed traits and clonal spreading ability. Results We detected no effect of common milkweed on total species richness, but it had a negative effect on the cover of grassland species. The negative effect of common milkweed was most pronounced on the cover of species with low SLA, low seed mass and low clonal spreading ability. Conclusions Our results suggest that native, late successional sandy grasslands invaded by common milkweed form undesirable novel ecosystems because of significant negative impacts on the cover of native grassland species, especially those species with low competitive ability. For these species, management of milkweed might be needed to ensure their persistence in sandy grasslands in this landscape.

In Central‐ and Eastern Europe, the collapse of socialist regimes resulted in a transformation of state‐owned agricultural cooperatives to privately owned lands from the early 1990s onwards. These socioeconomic processes resulted in landscape‐scale changes in biodiversity, ecosystem services and agricultural production. In parallel, large‐scale abandonment of croplands, especially on sandy, salty or frequently inundated areas, became common. Abandoned croplands are usually sensitive to species invasions, and are hotspots of noxious weeds, posing threats both to agriculture and nature conservation. Grassland restoration on former croplands can be an effective strategy for suppressing these species. Thus, a common goal of nature conservation and agriculture can be the restoration of grasslands on former croplands to (1) suppress weed and/or invasive species in line with the EU policy “Good Farming Practices”, (2) support animal husbandry by creating meadows or pastures, and to (3) recover biodiversity and ecosystem services. In the present paper we report “best practices” of grassland restoration projects from Hungary. Our aim was to compare the effectiveness of spontaneous grassland recovery vs. active grassland restoration by seed sowing in terms of the recovery of biodiversity and ecosystem services, such as weed control and biomass production. Our results showed that grassland restoration on abandoned fields offers a viable solution for restoring biodiversity and ecosystem services. Seed sowing ensures higher weed control and biomass production, but results in lower biodiversity compared to spontaneous recovery. Both restoration methods can be cost‐effective, or even profitable even within a relatively short period of a nature conservation project.

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