Assessing which weed species are likely to expand under climate change is essential for proactive management. While climate-driven range expansions of many weed species have been documented globally, projections for their future spread in Central Europe remain limited and poorly understood. We used ensemble species distribution models for 23 weed species that are currently emerging in Central Europe to evaluate their climatically suitable areas at present and future time periods (2041-2060, 2061-2080 and, 2081-2100) under four different future climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). The climatic suitability of our study area is predicted to increase for all species in the two earlier time periods and under moderate climate change conditions. However, climate change is likely to reduce the potentially suitable area in later time periods and under more severe scenarios. The climatically suitable area is expected to decline or remain stable for 14 of the modelled species, of which two thirds show a decline by 2100, regardless of the climatic trajectory. Furthermore, hotspots of climatic suitability, where multiple emerging weeds overlap are shifting northwest under the two more moderate climate change scenarios, whereas under the two severe climate change scenarios, hotspots are likely to shrink by 2100. Additionally, we found that most of the modelled species whose suitable area increases are C4 plant species, while those with decreasing suitability are predominantly C3 plants. Our findings underscore the importance of monitoring and proactive management strategies to mitigate the impacts of emerging weeds, particularly those better adapted to future climatic conditions.

Urban areas serve as hubs for non-native plant introductions, but the extent to which these introductions have homogenized city floras globally remains unexplored. We analyzed species inventories from 553 cities across six continents and show that non-native plants increase mean pairwise floristic similarity by ~50%, from a Jaccard index of 0.11 for native species alone to 0.16 when non-natives are included. Non-natives increase intracontinental similarity by 25%, but boost intercontinental similarity by 423%, due to intercontinental native floras sharing few species. City connectivity (indexed by air-travel frequency) amplifies non-native similarity more than native similarity, while geographic distance constrains native similarity more strongly, consistent with dispersal limitation. Contrary to our original hypothesis, climatic distance constrains non-native similarity as strongly as native similarity, confirming that climate is a hard environmental filter regardless of species’ origin. Meanwhile, urban socio-economic and physical features also affect native and non-native floristic similarity comparably. Regional analyses reveal pronounced asymmetries, with non-native species strongly homogenizing cities in Europe, North America, and Oceania, whereas Asian cities show weak intercontinental convergence. Decomposing similarity into ecological components reveals distinct mechanisms: homogenization between city pairs that involve European cities is dominated by species transfers (taxa native in one region but naturalized in another), reflecting colonial and trade legacies, whereas North American-Oceanian convergence is driven by a shared pool of widespread non-native species. These findings demonstrate that human-mediated plant movement has become a dominant force reshaping global urban flora, with effects modulated by connectivity, environmental filtering, and region-specific historical legacies.

Aims: Topography and canopy structure are key environmental filters for the trait-mediated assembly of understories, especially in mountain areas. Although changes in functional diversity (FD) along elevational gradients have been described in the past, the importance of slope aspect or the coincidental change of the canopy structure is generally unaccounted for. In this study, we aim to assess (i) whether the relationship between understory FD and elevation varies between north- and south-facing slopes and (ii) whether the canopy structure acts as a mediator between local topography and FD. Location: Central Apennines, Italy. Methods: We conducted a transect-based field sampling in forests on opposing slopes in the central Apennines, stretching from the valley bottom to the climatic treeline at similar to 2000 m. By linking the species distribution and abundance data with plant functional traits from publicly available databases, we modeled the change of single- and multi-trait FD along the elevational gradient. To test for the importance of slope aspect and the mediatory effect of canopy structure on understory FD, we used regression analysis and comparisons between two competing multiple linear models (topography vs. canopy structure). Results: We found that FD generally decreased along south-facing slopes, with no clear pattern on north-facing slopes, which indicates that different filtering regimes act on the understory in temperate forests depending on the slope aspect. Secondly, we found that for multi-trait FD, elevation and aspect influence the understory both directly and indirectly through differences in the canopy structure, which changes from mixed broadleaf forest to monodominant stands of Fagus sylvatica. For the diversity of single-trait FD, topography itself explained a higher amount of variation. Conclusion: Our results underline the need to account for slope aspect in the study of understory FD and the role that the canopy layer plays in mediating between elevation, aspect, and the understory.

Urbanization, together with land use changes, significantly transforms surrounding habitats, affecting the occurrence of plant species and the diversity of communities they form. However, detailed information on the individual environmental drivers influencing plant species composition of suburban forests remains limited. In this study, we ask: What are the main drivers of plant species diversity in suburban forests? In the city of Brno, Czech Republic, and its surroundings, we surveyed 110 vegetation plots of acidophilous oak and hornbeam forests. Using generalized linear models and canonical correspondence analysis, we studied the effects of urban environmental drivers on various plant species characteristics. Urbanization was the most significant driver since artificial surfaces near forests decreased total species richness and increased both the disturbance severity and the proportion of non-native species. Larger forest areas supported the presence of forest specialists and limited the spread of competitive generalists. Open forest stands surrounded by agricultural areas promoted the persistence of threatened species. Despite the prevailing acidic bedrock, variation in soil pH - common in urban areas - also influenced plant species diversity. In addition, forest management significantly affected vegetation composition, independently of the surrounding land use. Based on our findings, ensuring sufficient forest area, minimizing disturbance, maintaining habitat continuity, and enhancing landscape connectivity are essential for conservation of near-natural forests in urban planning. Management of oak and hornbeam forests should aim to create more open stands, support understorey regeneration, and prevent environmental degradation to sustain their required ecosystem functions.

Aim: To (a) produce a list of the most widespread naturalised non-native plant species across cities of the world; (b) explore whether cities on different continents are invaded by the same group of widespread naturalised species; and (c) elucidate the origins of the most widespread naturalised urban species. Location: Global. Time Period: No specific period. Major Taxa Studied: Vascular plants. Method: Using the most comprehensive and up-to-date dataset of non-native urban floras yet assembled (GUBIC; Global Urban Biological Invasions Compendium), we identified the most widespread naturalised plant species (the global urban florome) by filtering for taxa present across all continents (except Antarctica) and their frequency in urban areas. To assess global patterns of urban plant naturalisation, we conducted ordination analyses and visualised species co-occurrence. We also examined species origins and their environmental impact. Results: Among the 7792 naturalised plant species recorded in 553 urban centres, 302 species (4%) were found on all six continents. Of these, 96 species, considered the most widespread species, were present in more than half of urban centres in Oceania, North America and South America; this proportion was higher than in Africa, Asia and Europe. Cities outside Europe and Asia are more homogeneous in terms of the species composition of the most widespread invaders. An analysis of species origins showed that temperate Asia contributed the most species globally, while intercontinental exchange patterns varied, with a notable one-directional flow from North to South America. Main Conclusions: Our results suggest that urban ecosystems outside Europe and Asia are more susceptible to recent invasions than those within these two continents. Understanding the composition and origins of these widespread species is crucial for developing coordinated management strategies and improving the resilience of urban biodiversity.

Biodiversity assessments are critically affected by the spatial scale at which species richness is measured. How species richness accumulates with sampling area depends on natural and anthropogenic processes whose effects can change depending on the spatial scale considered. These accumulation dynamics, described by the species-area relationship (SAR), are challenging to assess because most biodiversity surveys are restricted to sampling areas much smaller than the scales at which these processes operate. Here, we combine sampling theory and deep learning to predict local species richness within arbitrarily large sampling areas, enabling for the first time to estimate spatial differences in SARs. We demonstrate our approach by predicting vascular plant species richness across Europe and evaluate predictions against an independent dataset of plant community inventories. The resulting model, named deep SAR, delivers multi-scale species richness maps, improving coarse grain richness estimates by 32

Alien species are increasingly prevalent worldwide, leading to economic and biodiversity losses. We examined how the spread of non-crop alien plant species (i.e., archaeophytes and neophytes) has evolved in arable fields across ten countries in central Europe from 1930 to 2019. Specifically, we analyzed how regional and local trajectories of alien plant species have changed over the last ninety years. We used a dataset of 21,747 vegetation plots from the AgriWeedClim database and applied generalized linear mixed-effect models. We analyzed the percentage of plots containing neophytes to characterize regional scale dynamics, as well as the proportional number and relative abundance of alien species per plot, offering insights into the local scale dynamics of alien species spread in arable fields. The dynamics of species populations in the study area revealed significant contrasts between neophytes and archaeophytes over time. The percentage of plots containing neophytes strongly increased from 34.2 % in 1930 to 70.1 % in 2019. The proportion of neophytes, in plots nearly doubled from 5.5 % in 1930 to 10.2 % in 2019. The relative abundance, meaning their biomass relative to the total biomass of all species in the plot, of neophytes followed a similar upward trend increasing from 4.1 % to 9.9 %. This highlights not only the spatial spread of neophytes in arable vegetation but also their increasing cover on the local scale. Archaeophyte species displayed a different trajectory. Their proportion exhibited only a modest increase from 23.2 % to 25.3 % over the ninety-year period, while their relative abundance slightly decreased from 21.2 % to 19.5 %. A sensitivity analysis of our data further revealed that the temporal increase in the percentage of plots containing neophytes is mainly driven by a few common species, such as Veronica persica and Erigeron annuus, which had a high number of records during the study period. We anticipate an increasing occurrence of neophytes in local communities in the future, which may contribute to the homogenization of regional arable plant communities.

Demand for material outputs, such as food and fuel, has led to intensification of agricultural production across European landscapes. At the same time, the potential for other Nature’s Contributions to People (NCP), such as climate regulation and cultural heritage, has diminished. Understanding how stakeholders in Europe value different NCP is critical for informing equitable land use decisions. However, many large-scale NCP assessments have focused on instrumental values, and studies on stakeholder preferences have mainly focused on local or regional scales, despite the prominent role of the European Union in shaping land use policies. This paper explores NCP preferences and their potential drivers among stakeholders across 15 countries and five European regions, using a geographically stratified sample of 152 case studies in 88 peer-reviewed scientific articles. Results show that stakeholders across Europe highly value physical and psychological experiences. We also found that preferred NCP appears to be more dependent on the assessed ecosystem than on spatial context or stakeholder characteristics overall. Specifically, stakeholders in urban systems tend to place more emphasis on non-material and regulating NCPs, while those in agricultural systems seem to prioritize material NCPs. However, these patterns vary across case studies. Our main results highlight a discrepancy between the non-material NCPs most frequently mentioned by stakeholders involved in the studies and the material and regulating NCPs prioritized in key international land use policies. Insights into stakeholder preferences at the European scale can help inform and enhance the integration of the pluralistic values people ascribe to nature into such policies.

Past glacial periods were highly disruptive to plant species distributions in mid-latitude mountain belts, such as the European Alps, and drove many species to survive in peripheral or nunatak refugia. Progressive glacial retreat during the late Pleistocene and Holocene is thought to have triggered a mass recolonization event in the European Alps. Here, we asked whether this recolonization event has left a spatial legacy in the floristic patterns of the extant Alpine flora, and if so, how strongly this determines floristic patterns in comparison to present-day landscape and climatic drivers. We built on approximately 6 million data points sourced from the Global Biodiversity Information Facility and herbaria to build plant species ranges within a 10 3 10 km grid system laid across the European Alps, and then calculated species assemblage turnover across the grid. Additionally, we used a recent species-level molecular phylogeny encompassing over 80% of the Alpine flora to calculate standardized phylogenetic diversity, phylogenetic endemism, and phylogenetic turnover between grid cells. Using spatial autoregressive and generalised dissimilarity modelling, we showed that all floristic measures vary significantly, albeit weakly, with three key post-glacial variables: climate change velocity, time since deglaciation, and distance from the nearest refugium. Unexpectedly, differences in species' dispersal ability did not explain these patterns. The post-glacial variables have little explanatory power relative to contemporary climate and landscape drivers. We conclude that post-glacial recolonization of the Alps is largely complete for the flora as a whole, and that the spatial structure of the extant flora is primarily driven by the contemporary environmental conditions.

Urban areas are foci for the introduction of non‐native plant species, and they often act as launching sites for invasions into the wider environment. Although interest in biological invasions in urban areas is growing rapidly, and the extent and complexity of problems associated with invasions in these systems have increased, data on the composition and numbers of non‐native plants in urbanized areas remain scattered and idiosyncratic. We assembled data from multiple sources to create the Global Urban Biological Invasions Compendium (GUBIC) for vascular plants representing 553 urban centres from 61 countries across every continent except Antarctica. The GUBIC repository includes 8140 non‐native plant species from 253 families. The number of urban centres in which these non‐native species occurred had a log‐normal distribution, with 65.2% of non‐native species occurring in fewer than 10 urban centres. Practical implications : The dataset has wider applications for urban ecology, invasion biology, macroecology, conservation, urban planning and sustainability. We hope this dataset will stimulate future research in invasion ecology related to the diversity and distributional patterns of non‐native flora across urban centres worldwide. Further, this information should aid the early detection and risk assessment of potential invasive species, inform policy development and assist in setting management priorities.

How alien plant species integrate into local native communities remains a widely debated but largely unresolved question. For 12,460 plant communities from six different habitats, we show that naturalized non-invasive species integrate near the center of the multidimensional functional trait space of each community, whereas invasive species tend to occupy the edges. This pattern is driven mainly by specific leaf area, plant height and seed mass, followed by genome size. These results suggest that functional similarity to resident native species supports successful naturalization of alien species through preadaptation to environmental conditions. In contrast, the functional dissimilarity of invasive species enables them to exploit new niches, potentially avoiding direct competition with co-occurring native species while still passing through environmental filters. The magnitude of differences between native, naturalized and invasive species is habitat-specific, reflecting both the local ecological conditions and the traits of the most widespread species in a given habitat.

Recent data and syntheses in central Europe have led to the development of synthetic variables for describing the successional orderings of species. In particular, the "successional optimum" (SO), developed for describing the vegetation in the Czech Republic, reflects the number of years it takes for a species to reach peak abundance after a disturbance. The aim is to combine data on a species' functional traits and Ellenberg-type indicator values, in order to identify the main plant strategies and environmental factors that predict SO. In this study, linear models with regularization techniques and robust inference methods were used to determine the traits that explain species' SO, and then an analysis of the explained variance was used to assess the relative explanatory power of each trait. In parallel, the effects of Ellenberg-type indicator values, before and after detrending the SO by traits, were determined. This revealed that five traits had the greatest and most consistent effects: therophytic life form, seed mass, flowering duration, bud bank size and leaf dry matter content. The most important Ellenberg-type indicator values predicting SO were moisture and reaction, as light and nutrient concentrations were associated with these traits. The effects of traits were generally consistent and universal in the different environmental conditions, as the interaction of traits and environment did not change inferences or result in better models. This resulted in a robustly defined strategy that relates species to their successional ordering, highlighting the importance of life forms, competitive abilities, and reproductive strategies in succession.

The globalization of trade and increased human mobility have facilitated the introduction and spread of nonnative species, posing significant threats to biodiversity and human well-being. As centers of global trade and human populations, cities are foci for the introduction, establishment, and spread of nonnative species. We present a global synthesis of urban characteristics that drive biological invasions within and across cities, focusing on four axes: ( a ) connectivity, ( b ) physical properties, ( c ) culture and socioeconomics, and ( d ) biogeography and climate. Urban characteristics such as increased connectivity within and among cities, city size and age, and wealth emerged as important drivers of nonnative species diversity and spread, while the relative importance of biogeographic and climate drivers varied considerably. Elaborating how these characteristics shape biological invasions in cities is crucial for designing and implementing strategies to mitigate the impacts of invasions on ecological systems and human well-being.

Elton's biotic resistance hypothesis posits that species-rich communities are more resistant to invasion. However, it remains unknown how species, phylogenetic and functional richness, along with environmental and human-impact factors, collectively affect plant invasion as alien species progress along the introduction-naturalization-invasion continuum. Using data from 12,056 local plant communities of the Czech Republic, this study reveals varying effects of these factors on the presence and richness of alien species at different invasion stages, highlighting the complexity of the invasion process. Specifically, we demonstrate that although species richness and functional richness of resident communities had mostly negative effects on alien species presence and richness, the strength and sometimes also direction of these effects varied along the continuum. Our study not only underscores that evidence for or against Elton's biotic resistance hypothesis may be stage-dependent but also suggests that other invasion hypotheses should be carefully revisited given their potential stage-dependent nature. According to Elton's biotic resistance hypothesis, species-rich communities are more resistant to plant invasion. Guo et al. examine a dataset of over 12,000 vegetation plots and report that the influence of resident community richness and relatedness on invasion resistance varies in direction and magnitude along the introduction-naturalization-invasion continuum.

The first comprehensive phytosociological classification of all vegetation types in Europe (EuroVegChecklist; Applied Vegetation Science, 2016, 19, 3-264) contained brief descriptions of each type. However, these descriptions were not standardized and mentioned only the most distinct features of each vegetation type. The practical application of the vegetation classification system could be enhanced if users had the option to select sets of vegetation types based on various combinations of structural, ecological, and biogeographical attributes. Based on a literature review and expert knowledge, we created a new database that assigns standardized categorical attributes of 12 variables to each of the 1106 alliances dominated by vascular plants defined in EuroVegChecklist. These variables include dominant life form, phenological optimum, substrate moisture, substrate reaction, salinity, nutrient status, soil organic matter, vegetation region, elevational vegetation belt, azonality, successional status and naturalness. The new database has the potential to enhance the usefulness of phytosociological classification for researchers and practitioners and to help understand this classification to non-specialists.

AimsThe Raunki AE r's system classifies vascular plants into life forms based on the position of renewal buds during periods unfavourable for plant growth. Despite the importance of Raunki AE r's system for ecological research, a study exploring the diversity and distribution of life forms on a continental scale is missing. We aim to (i) map the diversity and distribution of life forms in European vegetation and (ii) test for effects of bioclimatic variables while controlling for habitat-specific responses.LocationEurope.MethodsWe used data on life forms of 8883 species recorded in 546,501 vegetation plots of different habitats (forest, grassland, scrub and wetland). For each plot, we calculated: (i) the proportion of species of each life form and (ii) the richness and evenness of life forms. We mapped these plot-level metrics averaged across 50 km x 50 km grid cells and modelled their response to bioclimatic variables.ResultsHemicryptophytes were the most widespread life form, especially in the temperate zone of Central Europe. Conversely, therophyte and chamaephyte species were more common in the Mediterranean as well as in the dry temperate regions. Moreover, chamaephytes were also more common in the boreal and arctic zones. Higher proportions of phanerophytes were found in the Mediterranean. Overall, a higher richness of life forms was found at lower latitudes while evenness showed more spatially heterogeneous patterns. Habitat type was the main discriminator for most of the responses analysed, but several moisture-related predictors still showed a marked effect on the diversity of therophytes and chamaephytes.ConclusionsOur maps can be used as a tool for future biogeographic and macro-ecological research at a continental scale. Habitat type and bioclimatic conditions are key for regulating the diversity and distribution of plant life forms, with concomitant consequences for the response of functional diversity in European vegetation to global environmental changes. We analysed the diversity and distribution of plant life forms across Europe. Hemicryptophytes dominate in central Europe, while therophytes and chamaephytes thrive in the Mediterranean and dry temperate regions, and chamaephytes also in northern Europe. Habitat type strongly influences these patterns and moisture-related predictors impact therophyte and chamaephyte diversity.image

AimsThe Raunki AE r's system classifies vascular plants into life forms based on the position of renewal buds during periods unfavourable for plant growth. Despite the importance of Raunki AE r's system for ecological research, a study exploring the diversity and distribution of life forms on a continental scale is missing. We aim to (i) map the diversity and distribution of life forms in European vegetation and (ii) test for effects of bioclimatic variables while controlling for habitat-specific responses.LocationEurope.MethodsWe used data on life forms of 8883 species recorded in 546,501 vegetation plots of different habitats (forest, grassland, scrub and wetland). For each plot, we calculated: (i) the proportion of species of each life form and (ii) the richness and evenness of life forms. We mapped these plot-level metrics averaged across 50 km x 50 km grid cells and modelled their response to bioclimatic variables.ResultsHemicryptophytes were the most widespread life form, especially in the temperate zone of Central Europe. Conversely, therophyte and chamaephyte species were more common in the Mediterranean as well as in the dry temperate regions. Moreover, chamaephytes were also more common in the boreal and arctic zones. Higher proportions of phanerophytes were found in the Mediterranean. Overall, a higher richness of life forms was found at lower latitudes while evenness showed more spatially heterogeneous patterns. Habitat type was the main discriminator for most of the responses analysed, but several moisture-related predictors still showed a marked effect on the diversity of therophytes and chamaephytes.ConclusionsOur maps can be used as a tool for future biogeographic and macro-ecological research at a continental scale. Habitat type and bioclimatic conditions are key for regulating the diversity and distribution of plant life forms, with concomitant consequences for the response of functional diversity in European vegetation to global environmental changes. We analysed the diversity and distribution of plant life forms across Europe. Hemicryptophytes dominate in central Europe, while therophytes and chamaephytes thrive in the Mediterranean and dry temperate regions, and chamaephytes also in northern Europe. Habitat type strongly influences these patterns and moisture-related predictors impact therophyte and chamaephyte diversity.image

We studied changes in vascular plant species occurring in Central European (Germany, Czech Republic, Slovakia, Switzerland, Liechtenstein, Austria, Hungary, Northern Italy, Slovenia and Croatia) arable fields and their edges from 1930 to 2019. To correct for bias in the data, we used occupancy modeling to analyze changes in the occupancy, i.e., distribution ranges sizes, of the 359 most common species in the AgriWeedClim database. We used ecological indicator values, native versus alien (archaeophyte, neophyte) status, and species affinity to arable habitats to assess changes in the occupancy of species with different environmental preferences and biogeographic origins. We found only a small decline in overall species occupancy over time, with a median occupancy change of −0.1 %, possibly due to the exclusion of rare species from modeling. Species turnover was more pronounced, with 72 species decreasing to less than half of their initial occupancy and 77 species more than doubling their initial occupancy. Species with environmental preferences for nutrient-rich sites with neutral pH increased in occupancy whereas species typical for arable fields decreased. No response to climate change (i.e., increased occupancy of thermophilous or drought-tolerant species) was detected. Archaeophytes and native species decreased whereas neophytes increased in occupancy. Taken together, results suggest that the biodiversity of arable fields is changing largely in response to anthropogenic habitat changes.

Urban areas exert a significant influence on plant species assemblages. The mosaic of different urban land uses is reflected in the distribution patterns of different plant groups. Here we present the results of the first systematic and detailed floristic survey of the city of Brno, Czech Republic. We studied the flora of Brno from 2011 to 2021, and recorded all spontaneously occurring species in grid cells of 1.3 x 1.5 km. Our dataset includes 1,492 taxa found in the city, classified by their origin, residence time, invasion status, index of ecological specialization, and threat status in the Czech flora. Of these, 902 are native, 205 archaeophytes and 339 neophytes. The remaining 46 species with unknown status are probably remnants of cultivation or newly introduced species. Of the total list of species, 255 species are classified as threatened or near threatened in the Czech Republic. We analysed the effect of seven land-use categories on the proportions of these plant groups and found significant differences in the distribution of individual plant groups within the city. The proportions of plant groups except for threatened species reflected the proportions of individual land-use categories in the grid cells, although the strength and direction of these responses differed among plant groups. Native plant species richness was high in grid cells where forests predominate and the level of urbanization is low. In contrast, the proportion of archaeophytes and neophytes was much lower in the grid cells with a high proportion of forests. While archaeophytes predominated in the lowlands with agricultural land use, neophytes were more common in the central built-up areas of the city. To document the current distribution of all taxa found we supplement this study with a series of maps.