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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]

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]

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]

A central issue of community ecology is finding rules that explain the composition and abundance of coexisting species. Nowadays two main processes, environmental filtering and limiting similarity, are thought to play the main roles in structuring communities. Their relative importance under different environmental conditions, however, is still not properly clarified., We studied the strength and the effect of environmental filtering (causing convergence) and limiting similarity (causing divergence) in 137 sample plots along an extremely long environmental gradient ranging from open sand grasslands to highly productive marshes, using a trait-based approach. The main environmental gradient (i.e. productivity) was characterized by the Normalized Difference Vegetation Index, an indicator of above-ground live biomass. Cover of the plant species was estimated visually. Values of 11 plant traits were collected from field measurements and data bases. Mean and dispersion of the trait values of the plots were quantified by community-weighted means and Rao's quadratic entropy. Trait convergence and divergence were tested by randomization tests, followed by the study of changes in effect size along the productivity gradient by fitting generalized additive mixed models ( GAMM)., For vegetative traits we found mainly convergence, indicating the filtering effect of environmental constraints, while traits related to regeneration showed divergence., The strength of convergence in vegetative traits generally decreased as productivity grew, indicating that while under harsh conditions environmental constraints strongly limit the possible trait values, under more benign conditions various water and nutrient use strategies are adaptable. At high productivity, the strength of divergence in regenerative traits decreased. Since the larger diversity of vegetative traits found here reduces competition, the importance of diverse reproductive strategy is probably lower., Synthesis. Our results partly support the stress-dominance hypothesis, but reveal that assembly rules are more complex. The relative importance of environmental filtering and limiting similarity depends on the trait and on the environmental conditions of the habitat. Traits related to resource use are generally limited by environmental filtering, and this restriction is weakening as conditions become more favourable, while traits related to regeneration are constrained by limiting similarity and are more diverse under harsh conditions. [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]