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Aims: By analysing cattle‐ and sheep‐grazed sand grasslands, we tested the following hypotheses: (i) livestock type has a stronger effect on the vegetation characteristics than grazing intensity; (ii) sheep grazing results in lower biomass and species and functional diversity than cattle grazing, regardless of intensity; and (iii) increased grazing intensity causes a shift of the trait composition in grasslands. Location: Sand grasslands in the Nyírség region, East Hungary. Methods: We selected 26 sand grassland sites grazed by cattle or sheep and classified them into four intensity levels. Vegetation composition was surveyed in 2 m × 2 m plots. We harvested the above‐ground biomass from 20 cm × 20 cm plots; then dried and sorted it to live biomass, litter, moss, and lichen. We compared Rao dissimilarity index, species richness, Shannon diversity, evenness, and the community‐weighted means of nine vegetative and generative traits along a grazing intensity gradient. We calculated functional richness, evenness, and divergence for comparison. Results: We found that some diversity metrics and community‐weighted means of most studied traits were significantly affected by grazing intensity. Several characteristics were also affected by the interaction of grazing intensity and livestock type, but none of the studied characteristics was affected by livestock type in itself. Increasing Rao dissimilarity index peaking at the fourth grazing intensity level was detected, but for other multitrait indices, no such changes were proven, except for functional divergence, which was the lowest at the first intensity level. Graminoid, forb, and litter biomass were significantly affected by intensity, but none of the biomass fractions was affected by livestock type. Conclusions: We suggest that for the management of sand grasslands, grazing intensity should be carefully adjusted, considering not only livestock units per hectare. For practical recommendations, well‐defined, long‐term experiments studying different livestock and habitat types along an intensity gradient would be essential. [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]

A fundamental question in community ecology is how the quantity of floral resources affects pollinator activity and how this relates to the structure and robustness of pollination networks. The issue has been mainly addressed at the species level, while at the community level several questions are still open.Using a species‐rich semi‐natural grassland as model ecosystem, we explored the relationship between community‐level quantity of floral resources, the number of flower visits at community level and descriptors of the structure and robustness of pollination networks. To assess whether patterns of pollination interactions were consistent when using different types of floral resources, we measured three types of floral resources, namely the volume of nectar, the number of pollen grains and the number of flowers.Community‐level pollinator visitation rate showed a hump‐shaped relationship with the quantity of floral resources. Results were consistent among models employing different measures of floral resources as independent variables. The relationship between the quantity of floral resources and the structure and robustness of the network was not consistent among different types of floral resources; only intermediate levels of nectar volume were associated with high levels of network robustness.The pattern we found is in contrast with some former studies which reported positive linear relationships between the community‐level visitation rate of pollinators and the quantity of floral resources. Rather, the observed hump‐shaped pattern resembles the relationship previously found between the quantity of floral resources of a given plant species and its visitation rate per flower. Our results highlighted that, by using specific types of floral resources (e.g. the volume of nectar and the number of pollen grains), it is possible to reveal ecological processes that would be masked by using the number of flowers as the sole measure of floral resource. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Aims: We tested the establishment success of grassland species in the presence or absence of zoochory by livestock and identified the traits associated with successful establishment. Location: Hortobágy National Park, Hungary. Methods: In six restored species-poor grasslands we established two species-rich 4 m × 4 m source plots per site in 2013. One source plot was managed by extensive cattle grazing (“zoochory on”), the other one was fenced and protected from grazers (“zoochory off”). We monitored the vegetation development in the source plots (2014–2018), and the establishment success of sown species (2016–2018) in adjacent dispersal plots in four, 20-m-long strips per source plot in a total of 960 dispersal plots. We calculated community-weighted means of thirteen plant traits related to regeneration and competitive ability. The effect of grazing, year, distance from source plots, grazing–year and grazing–distance interactions on population and trait dynamics in the source and dispersal plots were analysed with generalized linear mixed-effect models. Results: Although grazing reduced the cover and flowering success of sown species in the source plots, the number of successful establishment events was higher in dispersal plots next to grazed source plots. The sown species were the most abundant in plots adjacent to source plots, but occurred at all monitored distances. Zoochory favoured perennial plants with high specific leaf area (SLA), low leaf dry matter content (LDMC), short stature, light seeds, early flowering period, high clonal index and anemochory index. Conclusions: We showed that species that can colonize the matrix with and without zoochory have contrasting trait syndromes. In grazing-adapted ecosystems, fencing source populations of target species does not always seem to be a good option. It was a good tool for increasing the cover and flowering success of the sown species in the short run, but it significantly decreased their chance to colonize the surrounding area in the long run. [ABSTRACT FROM AUTHOR]

Sowing grasses supports the rapid development of a closed perennial vegetation, which makes the method universally suitable for fast and effective landscape‐scale restoration of grasslands. However, to increase their diversity and to create a natural‐like species‐rich grassland is a challenging task. Understanding the role of seed bank compositional changes and vegetation dynamics can help to design management regimes that support the establishment of target species and suppress unwanted weeds. Our aim was to reveal the effect of post‐restoration management on the vegetation and seed bank dynamics in grasslands restored in one of the largest European landscape‐scale restoration projects. Eight years after restoration, we sampled the vegetation and the seed bank in 96 quadrats located in 12 restored grasslands in the Great Hungarian Plain. In each grassland stand, we studied and compared a mown (mown from Year 1 to Year 8) and an abandoned plot (mown from Year 1 to Year 3 then abandoned from Year 4 to Year 8). Mown and abandoned plots showed divergent vegetation and seed bank development. Abandonment led to the decline of sown grasses and higher cover of weeds, especially in the alkaline grasslands. Our study underlined that the developing seed bank had a limited contribution to the maintenance of biodiversity in both grassland types. We found that 5 years of abandonment had a larger effect on the seed bank than on the vegetation. We stress that long‐term management is crucial for controlling the emergence of the weeds from their dense seed bank in restored grasslands. [ABSTRACT FROM AUTHOR]

Sowing of grass seed mixtures is a feasible and cost‐effective method for landscape‐scale grassland restoration. However, sowing only grasses usually leads to species‐poor and dense swards, where the establishment of target forbs is hampered by microsite and propagule limitation. To overcome these limitations and increase the diversity of species‐poor sown grasslands, we developed a novel method by creating "establishment gaps.". We used tillage to open gaps of 1‐, 4‐, and 16‐m2 size in the dense grass sward of six species‐poor restored grasslands in the Great Hungarian Plain. We sowed high‐diversity seed mixtures of 35 native species into all gaps. We analyzed vegetation development during the first 5 years after setting up the trial. We also studied the colonization dynamics of the sown species along four 20‐m transects around each gap, resulting in a total of 1440 plots of 1‐m2 size that were studied. Our results indicated that most of the sown species were able to establish permanently in the gaps. The total cover and the cover of perennial sown species increased and the cover of short‐lived sown species decreased independent of gap size. There was only a moderate level of weed abundance in the gaps, and weed cover decreased over the years. The sown target species started to colonize the species‐poor grasslands surrounding the gaps within 5 years. The highest number of species and individuals dispersed from the 4‐m2 gaps, as they had a more stable development than smaller gaps and were exposed to lower grazing pressure than large ones. [ABSTRACT FROM AUTHOR]

Questions: Plant invasions are considered among the biggest threats to biodiversity worldwide. In a full‐factorial greenhouse experiment we analysed the effect of soil burial depth and litter cover on the germination of invasive plants. We hypothesised that: (a) burial depth and litter cover affect the germination of the studied species; (b) the effects of burial and litter cover interact with each other, and (c) the effects are species‐specific, but dependent on seed size. Methods: We tested the germination and seedling growth of 11 herbaceous invasive species in a full‐factorial experiment using four levels of seed burial depths and litter cover. We analysed the effect of burial, litter cover, and their interactions on germination, seedling length and biomass across species and at the species level. Results: Soil burial depth and litter cover had a significant effect on the germination of the studied species, but there were considerable differences between species. We observed a general trend of species with bigger seeds being not or less seriously affected by soil burial and litter cover than smaller‐seeded species. Correlations between seed weight and effect sizes mostly confirmed this general trend, but not in the case of soil burial. Conclusions: Our findings confirmed that seed size is a major driver of species' response to litter cover and to the combined effects of litter cover and soil burial, but there is no general trend regarding the response to soil burial depth. Despite its very small seeds, the germination of Cynodon dactylon was not affected by soil burial. The germination of Ambrosia artemisiifolia was hampered by both soil burial and litter cover despite its relatively large seeds. Thus, specific information on species' response to burial depth and litter accumulation is crucial when planning management or restoration in areas threatened by plant invasions. [ABSTRACT FROM AUTHOR]

Questions: Community assembly in regenerating forests is a key topic in ecology. Most studies examine the assembly process, assessing adult individuals along the forest succession. Although the adult stage is the final outcome of the assembly process, both abiotic and biotic filters can affect community assembly during early ontogenetic stages. Here, we investigate whether the functional composition and trait assembly patterns (trait convergence or divergence) change across ontogenetic stages along regenerating forest stands exposed to precipitation and chronic anthropogenic disturbance (CAD) gradients. Location: Caatinga dry forest, Catimbau National Park, Pernambuco, Brazil. Methods: Seeds (rain and bank), seedlings and adults of woody plant species were recorded across 15 forest regenerating stands (4–70 years since land abandonment) exposed to precipitation and CAD gradients. Seven functional traits related to species dispersal, establishment and resource use were measured for adult individuals and used to calculate the trait values for seeds and seedlings. Twenty old‐growth forest stands were used as a regional flora. Results: Functional composition (community weighted mean, CWM) varied across ontogenetic stages as wood density increased from seeds to seedlings, while seed mass increased from seeds to both seedlings and adults. The CWM also varied along precipitation/disturbance gradients but not along forest regeneration regardless the ontogenetic stage. Among seeds, dispersal distance increased towards wetter forest stands and decreased towards disturbed sites, while adult wood density increased from drier to wetter regenerating forest stands. Traits converged along the precipitation gradient but not in response to time since land abandonment. Conclusions: Caatinga dry forest regeneration is functionally structured across ontogenetic stages mediated mostly by water availability, but not over time since land abandonment. The effect of water availability on forest regeneration across ontogenetic stages highlights the complexity of species assembly in human modified landscapes, imposing important consequences considering the expected increasing aridity in the Caatinga. [ABSTRACT FROM AUTHOR]

Aims: The early phases in the life cycle of a plant are the bottleneck for successful species establishment thereby affecting population dynamics and distribution. In coastal environments, the spatial pattern of plant communities (i.e. vegetation zonation) follows the ecological gradient of abiotic stress changing with the distance from the sea. This pattern has been mainly explained based on the adaptation and tolerance to the abiotic stress of adult plants. However, the adult niche may considerably differ from the germination niche of a plant species. The aim of this work was to investigate to what extent abiotic factors (specifically salinity, temperature, nitrogen and their interactions) constrain seed germination along the sea–inland gradient. Location: Latium coast (Central Italy). Methods: Germination tests were performed on seeds of focal species of three different plant communities which establish at increasing distances from the coastline: Cakile maritima subsp. maritima, Elymus farctus, Crucianella maritima. We tested increasing concentrations of NaCl (one of the main abiotic factors which decrease across the sea–inland gradient), and their interactions with temperature and KNO3, to consider other factors which drive germination processes. Results: The tolerance to salinity significantly decreased in relation to the position of species along the coastal zonation. Crucianella maritima was shown to be the least tolerant species, having a decrease in germination >80% across all conditions. KNO3 significantly (although slightly) increased the germination percentage in Cakile maritima subsp. maritima and Elymus farctus. When combined with NaCl, KNO3 alleviated the negative effects of salinity only in Cakile maritima subsp. maritima. Conclusions: The germination responses to the interaction among the tested factors suggest that the germination niche may explain vegetation zonation filtering species at their early stages. Quantifying environmental niches in different phases of the life cycle of plants may provide important insights into community assembly processes. [ABSTRACT FROM AUTHOR]

Question: Human‐mediated dispersal (HMD) comprises human‐vectored dispersal (HVD; direct movement of organisms by people) and human‐altered dispersal (HAD; indirect change in dispersal patterns through human alteration of ecosystems). In the vegetation dynamics literature, human influence has primarily been studied in terms of perturbations to natural communities. Except for non‐native invasions, the role of HMD in vegetation dynamics has rarely been considered. Given the increasing human population and its pervasive impacts across the world, it is necessary to understand the different ways in which HMD drives changes in vegetation dynamics. Importantly how large are these influences and how do they disrupt natural processes? Method: We reviewed studies examining aspects of HMD in relation to vegetation dynamics and used the broader literature to inform a conceptual synthesis of the impacts of HMD on vegetation dynamics. Results & Conclusions: The propensity to be affected by HMD varies among species, and this is related to seed and plant traits. Together, these effects combine to determine whether HMD disrupts or enhances seed dispersal into a community. The ultimate consequences of changed arrival of seeds into a community are determined by the strength of the environmental and biotic filters, which govern the establishment and persistence of species. The effect of accidental HVD depends whether it follows the same rules as for natural dispersal; indeed humans might replace lost natural dispersers and thus enhance community resilience. Intentional HVD through sowing or planting will generally be highly disruptive especially as it often involves associated management. Traditionally, HAD has been considered to disrupt vegetation dynamics through, e.g., fragmentation or loss of natural dispersers. However, an HMD perspective can inform actions related to HAD that increase resilience, e.g., green infrastructure or vegetation management. Our framework encourages researchers to consider HMD holistically, to understand how the increasing human footprint might affect vegetation dynamics and resilience under future change. [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]

Question: Spontaneous succession is the most natural and cost‐effective solution for grassland restoration. However, little is known about the time required for the recovery of grassland functionality, i.e., for the recovery of reproductive and vegetative processes typical of pristine grasslands. Since these processes operate at different scales, we addressed the question: do reproductive and vegetative processes require different recovery times during spontaneous succession? Location: Kiskunság sand region (Central Hungary). Methods: As combinations of plant traits can be used to highlight general patterns in ecological processes, we compared reproductive (pollination‐ and dispersal‐related) and vegetative (growth form) traits between recovered grasslands of different age (<10 years old; 10–20 years old; 20–40 years old) and pristine grasslands. Results: During spontaneous succession, the reproductive trait spectra became similar to those of pristine grasslands earlier than the vegetative ones. In arable land abandoned for 10 years, pollination‐ and dispersal‐related trait spectra did not show significant difference to those of pristine grasslands; anemophily and anemochory were the prevailing strategies. Contrarily, significant differences in the growth form spectrum could be observed even after 40 years of abandonment; in recovered grasslands erect leafy species prevailed, while the fraction of dwarf shrubs and tussock‐forming species was significantly lower than in pristine grasslands. Conclusions: The recovery of the ecological processes of pristine grasslands might require different amounts of time, depending on the spatial scale at which they operate. The reproductive trait spectra recovered earlier than the vegetative one, since reproductive attributes first determine plant species sorting at the regional level towards their respective habitats. The recovery of the vegetative trait spectrum needs more time as vegetative‐based interactions operate on a smaller spatial scale. Thus, vegetative traits might be more effective in the long‐term assessment of restoration success than the reproductive ones. [ABSTRACT FROM AUTHOR]

In the Palaearctic steppe zone, overgrazing was identified as one of the key drivers of declining grassland biodiversity, which underlines the necessity of the functional evaluation of increased grazing pressure on grassland vegetation. We tested the following hypotheses: (a) The effect of grazing intensity on species and functional diversity is strongly dependent on grassland type. (b) The magnitude of diet selectivity of grazers decreases with increasing grazing intensity. (c) Increasing grazing intensity increases evenness and functional evenness of the subjected grasslands. We analyzed vegetation patterns in four types of grasslands (Dry alkali short‐grass steppes, Dry loess steppes, Non‐alkali wet and Alkali wet grasslands) along an intensity gradient of beef cattle grazing at 73 sites in Hungary. Species richness, Shannon diversity, evenness, and four leaf traits were analyzed. We calculated community‐weighted means for each single trait, and multi‐trait functional richness, functional evenness, and divergence for all leaf traits. All species and functional diversity metrics were significantly affected by the grassland type, except leaf dry matter content. The effect of interaction between grazing intensity and grassland type was also significant for functional richness, functional evenness, community‐weighted means of leaf area, and for species richness and evenness. An upward trend of specific leaf area was detected in all grasslands with the highest scores for the overgrazed sites, but the change was also grassland type dependent. The detected trend suggests that with increased intensity the overall selectivity of grazing decreased. We found that evenness was affected but functional evenness was not affected by grazing intensity. Functional evenness scores were more related to the grassland type than to changes in grazing intensity, and displayed a high variability. We stress that one‐size‐fits‐all strategies cannot be recommended and actions should be fine‐tuned at least at the level of grassland type. Our results clearly indicated that the effects of grazing intensity are strongly grassland type dependent. This implies that management strategies and decisions should be fine‐tuned at least at the level of grassland type. [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]

We aimed to introduce and test the 'seed mass-distribution range trade-off' hypothesis, that is, that range size is negatively related to seed mass due to the generally better dispersal ability of smaller seeds. Studying the effects of environmental factors on the seed mass and range size of species, we also aimed to identify habitats where species may be at risk and need extra conservation effort to avoid local extinctions. We collected data for seed mass, global range size, and indicators for environmental factors of the habitat for 1,600 species of the Pannonian Ecoregion (Central Europe) from the literature. We tested the relationship between species' seed mass, range size, and indicator values for soil moisture, light intensity, and nutrient supply. We found that seed mass is negatively correlated with range size; thus, a seed mass-distribution range trade-off was validated based on the studied large species pool. We found increasing seed mass with decreasing light intensity and increasing nutrient availability, but decreasing seed mass with increasing soil moisture. Range size increased with increasing soil moisture and nutrient supply, but decreased with increasing light intensity. Our results supported the hypothesis that there is a trade-off between seed mass and distribution range. We found that species of habitats characterized by low soil moisture and nutrient values but high light intensity values have small range size. This emphasizes that species of dry, infertile habitats, such as dry grasslands, could be more vulnerable to habitat fragmentation or degradation than species of wet and fertile habitats. The remarkably high number of species and the use of global distribution range in our study support our understanding of global biogeographic processes and patterns that are essential in defining conservation priorities. [ABSTRACT FROM AUTHOR]

Aims Cyanobacteria may have considerable effects on community functioning, mostly because they produce various metabolites that adversely affect other organisms. Here we synthesized existing knowledge about the effects of toxic cyanobacteria on the germination and growth of terrestrial plants. We also aimed to test the chemical effects of a Nostoc (Cyanobacteria) extract on the germination and growth of species of alkali habitats to investigate whether cyanobacteria can alter community structure and diversity via affecting the establishment success of plants. Location Cyanobacterium colonies from the Hortobágy National Park, east Hungary; indoor experiments at the University of Debrecen, Hungary. Methods To review the effects of toxic cyanobacteria on terrestrial plants, we conducted a literature search. To test these effects on native plants, field-collected Nostoc colonies were used to prepare a cell-free water extract, and treatments (watering with Nostoc extract and watering with tap water) were tested on 3 × 100 seeds of nine alkali grassland species. After 5 wk, seedling number, seedling length and fresh and dry weights were measured. Results We collected data on the effects of cyanobacteria on 27 species, but they were mostly focused on crops irrigated with cyanobacteria-containing water, not on floras native to natural ecosystems. In the germination experiment species identity and treatment had a significant effect on almost all variables, but their interaction only affected germination rate and fresh weight. Fresh weight decreased significantly only in the invasive Hordeum jubatum, but germination rate decreased significantly in five species. Conclusions Based on our findings, terrestrial cyanobacterium colonies can affect the establishment success of grassland plants, through which they may be important in determining which species can be incorporated into the community. Thus, cyanobacteria might play an important role in shaping diversity, species composition and the structure of natural plant communities. [ABSTRACT FROM AUTHOR]

Floral deception is widespread in orchids, with more than one-third of the species being pollinated this way. The evolutionary success of deceptive orchids is puzzling, as species employing this strategy are thought to have low reproductive success (less flowers yielding fruits) because of low pollination rates. However, direct measurements of total seed production in orchids - which is a better measure of reproductive success - are scarce due to the extremely small size of their seeds., Here, we quantified seed numbers in 1015 fruits belonging to 48 orchid species from the Pannonian ecoregion (central Europe) and obtained fruit set and thousand-seed weight data for these species from the literature. We used phylogenetic comparative methods to test the hypothesis that deceptive species should compensate for their lower fruit set by having either more flowers, larger seeds or more seeds in a fruit., Similarly to previous studies, we found that deceptive orchids have substantially lower fruits-set than nectar-rewarding ones. Also, we found that deceptive species have more seeds in a fruit but not more flowers or larger seeds compared to nectar-rewarding ones. Based on our results, deceptive species compensate for their lower fruit set by having higher seed numbers per fruit. As a consequence, their seed numbers per shoot do not differ from that of nectar-rewarding ones., Together with other benefits of deceptive pollination (e.g. lower energy expenditure due to the lack of nectar production and higher genetic variability due to decreased probability of geitonogamous pollination), our results can explain why deceptive strategies are so widespread in the orchid family., Synthesis. Our results indicate that deceptive orchids can compensate for their lower fruit set by having more (but not larger) seeds in a fruit than rewarding species. These findings highlight possible ways in which plants can increase their reproductive success in face of pollinator limitation. We emphasize that fruit set in itself is an inappropriate measure of the reproductive success of orchids - the total number of seeds per shoot is a much better approximation. [ABSTRACT FROM AUTHOR]