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Aim s : Ecological theories predict that assembly processes are driven by two deterministic forces: environmental filtering and limiting similarity. Their relative importance under different environmental conditions is still not completely obvious. Therefore, in this paper the predictions of the stress–dominance hypothesis (SDH) are tested in several sites. Location: Kiskunság in Hungary, and Deliblato Sands in Serbia, Central Europe. Methods: We studied a productivity gradient from open sand grasslands to meadows. The cover of species was estimated visually in plots with a size of 2 m × 2 m, resulting in 344 vegetation plots. Four trait values (height, seed mass, specific leaf area, and leaf size) were collected from field measurements and databases. The weighted median of interspecies distances in traits (a robust alternative to Rao's quadratic entropy) was used to determine functional diversity. The convergence and divergence of each trait in communities were evaluated by randomization tests, and effect sizes were calculated for each plot. We used hierarchical general additive models (HGAM) to determine whether the trend of effect sizes along the productivity gradient is the same in different sites. Results: The HGAM approach indicated that trait variations follow global trends but are influenced by site‐specific effects. The exception is seed mass, whose variation did not have any trend. Both environmental filtering and limiting similarity exist in the communities, and mainly a shift from trait convergence to a divergence pattern along the productivity gradient was observed. Conclusion: The results are mainly congruent with theoretical expectations, but the results from the different sites did not lead to the same conclusion. Although traits follow a global trend, the site effect is not negligible. Critical evaluation of SDH using trait convergence/divergence patterns for exploring rules of community assembly points out the weaknesses of this hypothesis. Therefore, alternative ways of studying trait patterns should be found to better understand community organization. [ABSTRACT FROM AUTHOR]

Aims: The restoration of unused urban‐industrial areas has great conservation potential as it can sometimes create a win‐win situation in terms of nature conservation and economic benefits. Financial data of restoration projects are rarely published. To close this gap, we report the cost–benefit analysis of different landscaping methods used in the greening of the outskirts of a factory industrial area. Location: The study area is located in a factory area in Nyíregyháza, Nyírség, Hungary. Methods: In this study, we compare the costs of the implementation and maintenance of three different types of grasslands (intensively and extensively managed park lawns and semi‐natural grassland, called eco area) and the ecological benefits in terms of vegetation and potential for pollinators. Results: The implementation and maintenance costs of the extensively managed park lawn were more than ten‐fold higher than that of the eco area, despite the higher price of native plant material. The construction of the extensive park lawn is the cheapest, but the eco area pays off in ca. 1.5 years compared to it, taking into account the lower maintenance costs. Seven years after implementation, the eco area is the most species‐rich, hosting the highest number of natural constituent species, but with similar vegetation cover as in the intensively managed park lawn without costly maintenance. The cover and species richness of legumes and forbs are also higher in the eco area, ensuring a food source for pollinators. Conclusions: Our results support that introducing species‐rich and diverse grasslands with native, habitat specialist species as an alternative to traditional landscaping in urban‐industrial areas can be economically and ecologically rewarding. The higher costs of planning, plant material, and implementation pay off in a short time due to low maintenance costs and can lead to a win‐win situation for nature as well as for the local economy. [ABSTRACT FROM AUTHOR]

Invasion of alien species is one of the main drivers of land degradation threatening both natural and managed ecosystems. Ecological restoration is crucial in controlling invasion to improve biotic resistance and avoid further land degradation. We investigated the possibility of controlling the establishment of invasive alien species (IAS) by native seed addition. We tested if trait similarity or increased propagule pressure of native species results in the suppression of IAS at the early stage of development. We set up a sowing experiment with three widespread IAS in Hungary of different life forms and functional groups (Asclepias syriaca, Conyza canadensis, Tragus racemosus) and four Pannonic sand grassland species (Festuca vaginata, Galium verum, Gypsophila paniculata, Saponaria officinalis). We found no significant differences in germination ability and seedling emergence between native species and IAS, despite the differences in thousand‐seed weight. Using univariate general linear models, we found that the seedling establishment of IAS can be reduced by adding native species at high densities but also depending on the species identity. Instead of species of similar traits, the seeding of a competitor perennial grass of sand grasslands (F. vaginata) reduced the seedling emergence of all studied IAS the most. Our results confirm that IAS can be effectively controlled by native seed addition in the early establishment stage, especially applying higher densities and competitive species. We conclude that invasion‐resistant restoration can be achieved by the combination of several factors, including high‐density sowing of native species that match IAS in the early stage of development. [ABSTRACT FROM AUTHOR]

Question: This study aimed to assess the impact of the invasion of Asclepias syriaca, a perennial non-native herbaceous species, on basic soil attributes and vegetation composition, and to study the effect of mechanical control, namely the cutting of Asclepias, on target and other plant species. Location: Sandy region of Kiskunság National Park, Hungary, Central Europe. Methods: In ten old-fields, four 4 m × 4 m plots were established (n = 40), of which three were invaded by Asclepias, and one was uninvaded. The invaded plots were treated as: (1) all Asclepias shoots removed, (2) half of the Asclepias shoots removed, or (3) untreated. The treatment was conducted twice a year in summer during the period 2019-2021. Before the first treatment, soil and vegetation were sampled. Afterwards, vegetation monitoring was performed twice a year: the cover of each vascular plant species and the number of Asclepias shoots were recorded in each plot. Result: There were no differences in the studied soil attributes between the uninvaded and invaded plots. However, there were differences in vegetation composition, namely, the cover of sand grassland specialists was higher in uninvaded plots. Short-term cutting negatively affected Asclepias after two years. The cover of specialists did not change in response to treatments, but the cover of other neophyte plant species increased. Conclusions: Based on our results, the invasion of Asclepias changes the vegetation composition, but not the soil. Although short-term mowing can reduce the cover of Asclepias, but the grassland specialist plants do not regenerate; instead, secondary invasion occurs. We conclude that more time or additional treatment is required for native plant recovery. [ABSTRACT FROM AUTHOR]

Describing the rules of community assembly is a central topic of ecology. Studying successional processes through a trait-based null model approach can help to better understand the rules of community assembly. According to theoretical considerations, at the beginning of succession - after getting over the dispersal limitation stage - community composition is primarily shaped by environmental filters (generating functional convergence), while in later stages limiting similarity (generating functional divergence) will be dominant. However, empirical evidence does not clearly support theoretical expectations. Our aim was to detect the presence and changes of trait-based assembly processes during old-field succession based on twelve traits. Changes in vegetation composition were evaluated by a combination of time series and space-for-time substitution: conducting three resurveys of permanent plots on four old-field age-groups. The individual dispersion of traits was transformed into effect size (i.e. departure from null model expectation). The impact of time since abandonment on effect sizes was tested by generalized additive mixed effect models. We detected a non-random pattern for each trait in at least some part of the succession. Departure from randomness did not change significantly over time for six traits: seed mass, lateral spread and pollination type were divergent, while leaf size, generative height and length of flowering were convergent. Six traits had changing patterns along the succession. Four of them showed increasing divergence (e.g. dispersal type, LDMC), which supports our hypothesis. While two (SLA, life form) displayed increasing convergence, contrary to expectations. We confirmed the general hypothesis that convergence is predominant initially and that divergence can be detected later in succession for four traits. However, the large variation found in trait dispersion indicates that complex processes operate during succession. [ABSTRACT FROM AUTHOR]

Community assembly theory is suggested as a guiding principle for ecological restoration to help understand the mechanisms that structure biological communities and identify where restoration interventions are needed. We studied three hypotheses related to propagule limitation, stress‐dominance, and limiting similarity concepts in community assembly in a restoration field experiment with a trait‐based null model approach. The experiment aimed to assist the recovery of sand grassland on former arable land in the Kiskunság, Pannonian biogeographic region, Europe. Treatments included initial seeding of five grassland species, carbon amendment, low‐intensity mowing, and combinations in 1 m by 1 m plots in three old fields from 2003 to 2008. The distribution of 10 individual plant traits was compared to the null model and the effect of time and treatments were tested with linear mixed effect models. Initial seeding had the most visible impact on species and trait composition confirming propagule limitation in grassland recovery. Reducing nutrient availability through carbon amendment strengthened trait convergence for length of flowering as expected based on the stress‐dominance hypothesis. Mowing changed trait divergence to convergence for plant height with a strengthening impact with time, supporting our hypothesis of increasing dominance of limiting similarity with time. Our results support the idea that community assembly is simultaneously influenced by propagule limitation and multiple trait‐based processes that act through different traits. The limited impact of manipulating environmental filtering and limiting similarity compared to seeding, however, supports the view that only targeting the dispersal and environmental filters in parallel would improve restoration outcome. [ABSTRACT FROM AUTHOR]

Questions: The restoration of unused urban‐industrial areas has largely been neglected despite their great potential for nature conservation purposes. We applied three plant introduction treatments at a highly degraded industrial area to test whether plant material introduced onto industrial areas initiates plant assemblages similar in composition to those of reference grasslands. We specifically asked (a) Does restoration differ between primary and secondary reference sites in terms of overall species richness and cover three years after the introduction of plant material? (b) What is the sociability of species of the vegetation resulting from different treatments? Location: Restoration and reference grassland sites with acidic sandy soil in the temperate region of the EU, NE Hungary, Nyírség. Methods: As restoration techniques, we (a) directly seeded a single dominant species, (b) applied a commercial seed mixture, and (c) transferred hay. We compared species composition, cover, species richness and sociability of species in restoration treatments to reference grasslands. Inventories of vascular plant species were made at five randomly placed 2 m × 2 m sampling units per plot. Results: The species composition of seeded restoration plots (with a single dominant species and a commercial seed mixture) became similar to that of reference grasslands. Both types of seeding resulted in a similar cover, whereas seeding a commercial seed mixture and hay transfer resulted in a species richness similar to that of reference grasslands. The cover of the natural constituents (NC) of seeded plots also reached that of reference grasslands, while hay addition resulted in a lower cover and a higher number of NC than other methods. Conclusions: The introduction of propagules in degraded industrial areas can provide communities similar, after three years, to those of secondary reference grasslands that are 30 years of age. We conclude that investing in the restoration of native grasslands at unused urban‐industrial sites can be a great opportunity to enhance biodiversity. We applied three plant introduction treatments to restore sandy grasslands at an industrial area. The restored grassland was compared to reference grasslands. The treatments resulted in communities that, after three years, were similar to those of secondary reference grasslands with an age of 30 years. The restoration of native grasslands at unused urban‐industrial sites can therefore be a great opportunity to enhance biodiversity. [ABSTRACT FROM AUTHOR]

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Spontaneous succession is increasingly involved in grassland restoration, because it offers a cost‐effective solution compared to technical reclamation methods. This topic is especially important nowadays, as large areas of marginal croplands are being abandoned on poor soils of Central and Eastern Europe, which offers a possibility for the spontaneous recovery of typical target grasslands. Studying the vegetation composition, aboveground biomass, and seed bank in old fields of different age and target calcareous sand grasslands using the chronosequence method, we aimed to answer the following questions: (1) Which species contribute to the seed banks of old fields and reference grasslands? (2) Does the direction of vegetation and seed bank succession trend toward the reference grasslands? (3) How are the vegetation changes in spontaneous succession reflected by the soil seed banks of old fields? In reference grasslands on the dune tops only sporadic seed banks were detected, while several hygrophytes had dense seed banks in reference grasslands in dune slacks. Similarity between the species composition of vegetation and seed banks was low. The development of vegetation and seed banks in old fields progressed toward that of target grasslands and the proportion of weedy species (e.g. indigenous weeds and invasive species) also decreased with time. The cryptogam biomass correlated significantly negatively, while the soil phosphorus significantly positively with the weedy species seed bank density. Our results indicated that the role of persistent seed banks in the regeneration of calcareous sand grasslands from old fields is rather limited and promising vegetation changes are mostly driven by spatial dispersal. [ABSTRACT FROM AUTHOR]

Scaling-up ecological restoration demands the involvement of private sector actors. Experience regarding science-based habitat restoration programs in the sector should be made available to support further joint projects. In our case, hierarchical restoration prioritization was applied to select best target for habitat reconstruction at a Hungarian industrial area. Multiple potential natural vegetation model, a novel approach, supported restoration prioritization satisfying both ecological (sustainability and nature conservation value) and other needs (feasibility, rapid green surface, amenity, and education value). The target that met all priorities was the open steppe forest that has a mosaic arrangement with open and closed sand steppes. The potential area of this xero-thermophile oak wood is expected to expand in Hungary with climate change, therefore the selected target has a likelihood of long-term sustainability, if established. A matrix of sand steppes was created first at the factory area in 2014-2015, and tree and shrub saplings were planted in this matrix. The seeding induced rapid changes in vegetation composition: the second year samples became close to reference sand steppes in the principal component analysis ordination space. Tree and shrub survival was species dependent, reaching a maximum of 52 and 73% for tree and shrub species, respectively. One tree and 2 shrub species did not survive at all. Altogether 53 of 107 target species have established. So far, restored vegetation development confirmed the suitability of the applied hierarchical prioritization framework at factory scale. [ABSTRACT FROM AUTHOR]

Invasion of alien plant species is one of the main reasons for biodiversity loss in terrestrial ecosystems. However, alien plant species are not evenly distributed in the landscape. We studied which factors determine the actual level of neophyte invasion in a landscape with heterogeneous land-use and which habitats are the most infected. Since neophyte species with different life-forms can respond differently to the factors determining the invasion, species groups of annual, herbaceous perennial and woody neophytes were also analyzed separately. The study was conducted within the field site network of the Kiskun-LTER program (Hungary), in 16 sites of 5 km × 5 km. Fifteen habitat types were distinguished belonging to five major land-use/land cover types (agricultural land, abandoned agricultural land, tree plantation, semi-natural grassland and semi-natural forest). Present and past land-use, landscape composition and environmental variables were included as factors with a potential impact on the level of invasion. The most important factor determining invasion level was present habitat type, followed by the past habitat type of the location and landscape context. Tree plantations, agricultural habitats and recently abandoned agricultural habitats had the highest level of invasion. As expected, annual neophytes were most abundant in agricultural habitats, while perennial herbaceous neophytes were most abundant in old-fields and plantations, and woody neophytes in tree plantations. Past agricultural land-use was reflected in the higher levels of invasion of annuals and perennials, and past forestry practice resulted in higher levels of invasion of woody neophytes. In a landscape with a higher proportion of tree plantations, not only the tree plantations, but primary woodland patches also showed higher levels of invasion by woody neophyte species. Our results indicate the importance of present and past land-use in plant invasion and suggest that tree plantations are hot-spots of plant invasion and threaten the remnants of semi-natural vegetation. [ABSTRACT FROM AUTHOR]

Urban-industrial restoration of complex native vegetation, such as grassland-forest mosaics could counteract land degradation and help develop methodology for larger scale complex restorations. We have studied the impact of grassland reconstruction techniques, the resulting biotic conditions, plus abiotic conditions on early woody survival in a forest-steppe reconstruction at an urban-industrial site. The study area is situated at the factory of the LEGO Group, Nyíregyháza in the acidic inland sand dune region of Nyírség, NE Hungary, Europe. Over 10,000 undercut 1-2-year-old saplings of 16 tree and shrub species were planted in patches of various size in November 2015 at ca. 20% of the restoration area. Specific plans were developed for each woody patch within the restored grassland. Tree and shrub survival was counted for all saplings in all patches in the summer of 2016. Vegetation height, cover of herb-layer, and elevation a.m.s.l. were estimated for each woody patch and soils were characterized for each restoration parcel. First year woody survival rates ranged between 4 and 66% for the different species. Only vegetation height had an overall negative impact on woody survival and seven species reflected some (often contradictory) impacts of the studied environmental variables. In our interpretation this shows that woody survival was basically independent of the grassland reconstruction techniques, but also that the management of the herb-layer of new woody plantations can be crucial in long-term maintenance. Our results support that the reconstruction of complex native habitats with a park-like appearance is a viable alternative to landscaping in industrial areas that can counteract land degradation and increase green infrastructure connectivity. The methods applied can be transferred to larger-scale restoration with modifications. • Forest-steppe reconstruction is a viable alternative to traditional landscaping • The impact of grassland introduction technique on woody survival was limited • Only height of the grassland had some impact on early woody survival • Six species reflected some impact of bare surface, soil or elevation • Similar landscaping in unused land can increase green infrastructure connectivity [ABSTRACT FROM AUTHOR]

• In plantation forests of forest-steppe species richness of forest specialist herbs is very low. • Site preparationdecreases stronger their richness than planting alien trees. • With site preparation alien plants appear and establish permanently in plantations. • Continuity of natural oak forests is the key to preserve richness of specialists. In forestry, several types of management practices are used, which have significant effects on species richness and composition. A number of studies concerning the effect of management on biodiversity have been conducted in the tropical and temperate forest zones. This topic is less studied in the forest steppe biome, where the reestablishment of plants from the surrounding patches is more limited than in the forest biome. Most studies compare alien plantations with seminatural forests. However, the effects of dominant tree species is mixed with the effect of the site preparation and site history in such comparisons, due to intensive site preparation in case of forest plantations. In this study, we separate the effect of these management elements. We examined the potential of currently used forestry protocol in preserving the plant biodiversity of the forest herb layer in the Pannonian sand forest steppe using 266 forest plots from the Kiskunság sand region in Hungary. The total richness and richness of habitat preference groups (forest specialists, grassland specialists, native weeds, and aliens) were compared in natural and plantation forests of different tree species to explore the effects of dominant tree species and site preparation on the species composition. Factors determining the richness of forest specialists in plantations were analyzed by fitting a regression tree, and the habitat preference of these species was described by their fidelity to the forest types. Our results show that total species richness is less sensitive to management than the richness of some species groups with a specific habitat preference. Forest specialist species can survive almost only in continuous seminatural oak forests, that is, in forests that are continuously present and do not undergo any site preparation. They are completely missing from young plantations, most likely because site preparation completely removes them. Their limited recolonization is possible only in plantations of native trees in landscapes where seminatural oak forests have been continuously present. Even under these conditions, only half of the forest specialist species are able to recolonize in the plantations. Grassland specialists, on the other hand, are present in every forest type but with low richness. Site preparation acts as a colonization window for weeds and aliens. However, while the richness of weeds is the highest in young plantations and decreases in established plantations, probably due to the canopy closing, the richness of aliens is the same in both young and established plantations. Considering our results, the current forestry protocol is hardly suitable for maintaining the plant biodiversity of forests in the forest steppe zone, therefore, management practices should be changed to focus more on the conservation of these endangered habitats. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of present and past landscape context examined on sand grassland biodiversity. [•] Primary grassland specialist species defined by statistical fidelity measures. [•] Present landscape had no significant relationship with specialist species richness. [•] Landscape context of 19th century affects significantly the present biodiversity. [•] Long term delay of species loss is consistent with the extinction debt hypothesis. [ABSTRACT FROM AUTHOR]

• Plant diversities of quasi natural and moderately managed sites were compared in six major Pannonian habitat complexes. • Novel bootstrap statistics is useful for comparison of diversities of heterogeneous sites. • Gamma diversity (species richness) of specialist species is the most sensitive diversity indicator. • The diversity of loess and dolomite forest steppe complexes and freshwater marshlands is significantly lower in managed sites. • Reduced diversity is coupled with habitat loss. Habitat complexes exhibit varying vulnerability to human land use and thus have different impacts on biodiversity. In this study, we analyzed the effect of moderate land use on the plant species diversity in six characteristic Pannonian habitat complexes: forest steppe complex on sand, on dolomite, and on loess, as well as alkaline habitat complex, freshwater marsh complex, and zonal broadleaf colline forest. We chose two regions for each complex, and in each region, we selected a 2 × 2 km "natural" study site in a mostly protected area, and a moderately used "managed" site of the same size. We compared the alpha, beta, and gamma diversities of the total and the specialist species pools of the natural-managed site pairs by applying stratified random sampling and novel bootstrap statistics. The gamma diversity of the specialist species pool was found to be the most sensitive indicator of naturalness. It was higher in the natural sites of the loess and dolomite forest steppe and the freshwater marshland complexes, while there were no significant diversity differences in the other complexes. The diversity comparisons showed a consistent pattern: there were either no significant diversity differences in any of the natural-managed pairs, or there were significant differences in the gamma diversities of the specialist species pool in both the natural-managed pairs. We concluded that the same differences in naturalness may represent different sensitivities to human management as characterized by differences in diversity measures. Three habitat complexes, the loess and dolomite forest steppe and the freshwater marshland, require more focused nature protection efforts in order to preserve the habitat diversity, especially in maintaining the remnants of the natural woody patches and the most inundated habitats of the marshlands. In the case of the other studied complexes, moderate human land use can be harmonized by nature protection goals. [ABSTRACT FROM AUTHOR]