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This study examined the effects of conservation management strategies, including traditional grazing, on marsh vegetation invaded by false indigo bush (Amorpha fruticosa L.) Fine‐scale methods were employed to analyze vegetation in stands subjected to combined treatments (mowing and grazing) as well as in untreated invaded stands. Vegetation composition and diversity were evaluated using four key metrics: compositional diversity (CD), local distinctiveness (LD), association (AS), and realized species combinations (NRC). Results revealed that the combined treatment led to significantly increased CD (5.366 ± 0.394) and LD (6.41 ± 0.668), despite the presence of the invasive species. Conversely, untreated invaded vegetation exhibited lower CD (3.756 ± 0.755) and LD (4.079 ± 0.93). Additionally, AS and NRC values were higher in treated stands, although the differences were not statistically significant. Notably, the characteristic areas of all functions did not differ significantly between treated and untreated stands. These findings suggest that combining management strategies, such as mowing and traditional grazing, effectively limits A. fruticosa invasion and supports marsh ecosystem diversity by promoting the coexistence of native species. Continuous management, particularly grazing, is crucial, as cessation of these practices may lead to rapid reinvasion by the invasive species and a subsequent loss of native biodiversity. Overall, this study highlights the importance of proactive management strategies in combating invasive species and conserving marshland biodiversity. [ABSTRACT FROM AUTHOR]

Functional traits, which shift as a plant develops from seed to adult and may be phylogenetically conserved, are widely acknowledged to be associated with exotic species invasion. However, existing studies comparing functional traits between native and invasive species often focus on a single ontogenetic stage, yielding mixed results. It remains unclear whether the functional trait differences and their relationship with invasiveness (e.g. range size) of exotic species remain consistent across ontogenetic stages. In this study, we experimentally compared 18 traits across the seed, early growth and adult stages of 127 native and exotic species from 19 families. These species are common and often co‐occur in the subtropical region of China. We also explored the linkage between these traits, alongside their phylogenetic relatedness with native species and exotic species' range size in China. Our results show that only seed mass differed between native and exotic species. Moreover, the compositions of traits across all stages and the entire lifespan were primarily influenced by phylogenetic relatedness rather than geographic origin. Further, the range size of exotic species in China positively correlated with their mean phylogenetic distance to native species, with no association with individual functional traits or functional distinctiveness. Synthesis. Our results emphasize the importance of comparing functional traits across ontogenetic stages between native and exotic species to improve our understanding of the role of functional traits in shaping plant invasion. Our findings also underscore the pivotal role of phylogenetic relatedness in shaping plant functional traits and the distribution of exotic species in their new ranges. [ABSTRACT FROM AUTHOR]

Many invasive plants can reproduce through both seeds and clonal growth. In habitats, interacting seedlings may originate from the same mother, and interacting ramets originating from the same plant may not be adjacent to each other in the stolon, particularly for vines that can show curved growth. However, in a homogeneous environment, how kinship and integration between adjacent/non-adjacent ramets affect plant growth and feedback with soil biota has been less studied. We address these questions using an invasive stoloniferous vine Mikania micrantha. We found that sibling groups and stranger groups did not differ in biomass production, root allocation and feedback with soil biota, indicating that kin recognition is unlikely in M. micrantha. For two-ramet stolon fragments in which interacting ramets were adjacent to each other, older ramets allocated more biomass to roots than younger ramets when integrated, particularly in comparison with disconnected ramets from different genotypes, indicating that a division of labor was induced. For four-ramet stolon fragments in which there were two unrooted ramets between the two rooted, interacting ramets, integration increased biomass allocation to roots, possibly because only two of the four ramets could absorb belowground resources and a lower shoot allocation decreased aboveground light competition. When inoculated with soil biota conditioned by the four-ramet integrated fragments, plants of M. micrantha also increased biomass allocation to roots. These results indicate that the distance between interacting ramets in the stolon may affect the integration effect and feedback with soil biota in clonal plants. [ABSTRACT FROM AUTHOR]

Summary Functional differences between native and exotic species, estimated when species are grown alone or in mixtures, are often used to predict the invasion risk of exotic species. However, it remains elusive whether the functional differences estimated by the two methods and their ability to predict species invasiveness (e.g. high abundance) are consistent. We compiled data from two common garden experiments, in which specific leaf area, height, and aboveground biomass of 64 common native and exotic invasive species in China were estimated when grown individually (pot) or in mixtures (field). Exotic species accumulated higher aboveground biomass than natives, but only when grown in field mixtures. Moreover, aboveground biomass and functional distinctiveness estimated in mixtures were more predictive of species persistence and relative abundance in the field mixtures in the second year than those estimated when grown alone. These findings suggest that assessing species traits while grown alone may underestimate the competitive advantage for some exotic species, highlighting the importance of trait‐by‐environment interactions in shaping species invasion. Therefore, we propose that integrating multi‐site or multi‐year field surveys and manipulative experiments is required to best identify the key trait(s) and environment(s) that interactively shape species invasion and community dynamics. [ABSTRACT FROM AUTHOR]

Globalization of social and economic activities has led to the large-scale redistribution of plant species. It is still unclear how the traits aid the successful invasion of alien species. Here, we downloaded global plant trait data from the TRY-Plant Trait Database and classified alien species in China into four groups: high, medium, need attention and harmless according to their distribution and degree of harm to local plant communities based on existed studies. The relationship between plant functional traits and invasion level was clarified, and we established a prediction model based on plant functional traits and taxonomy. The results showed that species with smaller seeds, smaller individuals, lower special leaf area and longer seed bank longevity (SL) are more likely to be an invasive species after introduction to foreign ecosystems. In summary, exotic species with longer SL and lower seed dry mass are more likely to be invasive in China. We also trained two predictive models to check if we can predict a species' invasion. Combining the two models together, statistically, we could predict if a species is invasive from its traits and taxonomy with a 91.84% accuracy. This model could help local governments, managers and stakeholders to evaluate shall we introduce some plant species in China. [ABSTRACT FROM AUTHOR]

Carex pilulifera L., a perennial herb native to Europe, was recently introduced and found in subalpine vegetation of Reunion Island. In this study, we assessed the current distribution and cover of C. pilulifera within the subalpine vegetation (Piton des Neiges and Piton de la Fournaise) of the National Park of Reunion. We used GLM models to analyse relationships between C. pilulifera and habitat, disturbance type, and proximity to fodder and grazing areas. We evaluated the potential distribution of C. pilulifera using species distribution models. Presence of C. pilulifera was only found on Piton de la Fournaise with a mean cover of 16.6% (where present). Carex pilulifera was the fourth most observed alien species (27% of all observations). According to the SDM, it could also occur in Piton des Neiges but was not found. Carex pilulifera was significatively more present in subalpine grasslands and close to grazing and fodder areas. We believed fodder and grazing areas to be the introduction pathways of this species. This study confirmed the status of C. pilulifera as an invasive species in the subalpine vegetation of Reunion Island which comprises a high level of plant endemism. We suggest that management should primarily focus on surveying potentially suitable areas in Piton des Neiges to eradicate new introduction and to control the species within high biodiversity areas in Piton de la Fournaise. [ABSTRACT FROM AUTHOR]

Abstract Background Previous studies into the interactions between native and invasive species under nitrogen (N) deposition have often overlooked the presence of co-occurring native species, a factor that could influence the outcomes of interspecific competition. Furthermore, publication bias may lead researchers to focus on rare native species with limited adaptability. In this study, we examined how two levels of N deposition affected the physiological and ecological traits and the interspecies interactions between three invasive and three common native species. Results N deposition promoted the growth of both invasive and native species. The relative dominance index (RDI) of invasive species was consistently higher than that of native species. Invasive species had an advantage over common native species in using the increased N effectively. The biomass distribution of invasive species was biased toward the aboveground parts, indicating competition for light resources. Conclusions N deposition conferred a stronger competitive advantage to invasive species than to native species, suggesting that the distribution range of invasive species may expand further under increased N deposition.

Suppression of roots and/or their symbiotic microorganisms, such as mycorrhizal fungi and rhizobia, is an effective way for alien plants to outcompete native plants. However, little is known about how invasive and native plants interact with the quantity and activity of nutrient-acquisition agents. Here a pot experiment was conducted with monoculture and mixed plantings of an invasive plant, Xanthium strumarium, and a common native legume, Glycine max. We measured traits related to root and nodule quantity and activity and mycorrhizal colonization. Compared to the monoculture, fine root quantity (biomass, surface area) and activity (root nitrogen (N) concentration, acid phosphatase activity) of G. max decreased in mixed plantings; nodule quantity (biomass) decreased by 45%, while nodule activity in N-fixing via rhizobium increased by 106%; mycorrhizal colonization was unaffected. Contribution of N fixation to leaf N content in G. max increased in the mixed plantings, and this increase was attributed to a decrease in the rhizosphere soil N of G. max in the mixed plantings. Increased root quantity and activity, along with a higher mycorrhizal association was observed in X. strumarium in the mixed compared to monoculture. Together, the invasive plant did not directly scavenge N from nodule-fixed N, but rather depleted the rhizosphere soil N of the legume, thereby stimulating the activity of N-fixation and increasing the dependence of the native legume on this N source. The quantity–activity framework holds promise for future studies on how native legumes respond to alien plant invasions.

Abstract [Objective] Invasion of Trifolium repens occupies the living space of turfgrasses and has been seriously threatening the quality and function of turfs. Examining the impact of T . repens invasion on the functional traits of Poa pratensis and turf quality is helpful for understanding the invasion mechanism of T . repens and for establishing and maintaining gramineous turfgrass. [Methods] Taking the T . repens-invaded P . pratensis turf as object, the sample survey method was employed to investigate the differences in the functional traits and turf quality of P . pratensis under different degrees of T . repens invasion (control, low invasion, moderate invasion, and heavy invasion), and to evaluate turf quality by the membership function method. [Results] (1) With increase in degree of T . repens invasion, the carbon content of P . pratensis organs and the cost of leaf construction, as well as the ratio of carbon to nitrogen, carbon to phosphorus, and nitrogen to phosphorus were gradually decreased, while the specific leaf area and nitrogen and phosphorus content in the organs were increased. (2) At the same invasion level, the carbon, nitrogen, and phosphorus contents in the organs of P . pratensis were higher in leaves than in roots and stems, and the carbon to nitrogen ratio and carbon to phosphorus ratio were higher in roots and stems than in leaves, while the nitrogen to phosphorus ratio was higher in stems and leaves than in roots. (3) The density, texture, greenness index, and uniformity of P . pratensis turf were decreased with increase in T . repens invasion, while the aboveground biomass and belowground biomass were increased. (4) The comprehensive evaluation by the membership function method showed that turf quality was the best without T . repens invasion but the worst under heavy T . repens invasion. Leaf carbon content had the greatest influence on turf quality. [Conclusion] T . repens invasion alters P . pratensis functional traits as well as affects turf quality, landscape, and function.

Biological invasions are a major threat to biodiversity because of invasive alien species’ high population growth rates and spread in new ranges. The inherent superiority hypothesis states that particular characteristics of alien species cause them to perform better than native species. Using a meta-analysis of 127 studies and more than 900 experimental observations comparing alien and native plant performance, we investigated, whether: (1) studies comparing alien and native performance generally support the inherent superiority hypothesis; (2) the direction and magnitude of superiority depend on the choice of performance measure; and (3) it depends on other aspects of the study design or species. We found that the inherent superiority hypothesis was overall supported, although the strength of this result depended on the chosen measure of effect size (a significant effect for the standardized mean difference SMD (Hedge's g) but not for the log response ratio LRR). Alien plant species were more likely to be found superior compared to natives if performance was measured in terms of growth, reproduction or response to natural enemies. Measuring survival or abundance was less likely to result in alien superiority, while for measurements of physiology and response to mutualists results were mixed. Furthermore, aspects of experimental design, selection and number of study species played an important role. We thus quantitatively showed across a broad range of conditions how choice of performance measure and experimental design affect the direction and magnitude of alien superiority found in small-scale studies. Furthermore, our review pointed out a lack of studies that assessed population growth as a direct determinant of true superiority. Conducting studies using performance measures relevant for superiority, while also considering other potentially important factors such as residence time, will shed more light on how common true alien superiority is and in which contexts it is to be expected.

Background: Previous studies into the interactions between native and invasive species under nitrogen (N) deposition have often overlooked the presence of co-occurring native species, a factor that could influence the outcomes of interspecific competition. Furthermore, publication bias may lead researchers to focus on rare native species with limited adaptability. In this study, we examined how two levels of N deposition affected the physiological and ecological traits and the interspecies interactions between three invasive and three common native species. Results: N deposition promoted the growth of both invasive and native species. The relative dominance index (RDI) of invasive species was consistently higher than that of native species. Invasive species had an advantage over common native species in using the increased N effectively. The biomass distribution of invasive species was biased toward the aboveground parts, indicating competition for light resources. Conclusions: N deposition conferred a stronger competitive advantage to invasive species than to native species, suggesting that the distribution range of invasive species may expand further under increased N deposition. [ABSTRACT FROM AUTHOR]

Soil microorganisms play a crucial role in the plant invasion process, acting as both drivers of and responders to plant invasion. However, the effects of plant invasion on the complexity and stability of co-occurrence networks of soil microbial communities remain unclear. Here, we investigated how the invasion of Spartina alterniflora affected the diversity, composition, and co-occurrence networks of soil bacterial and fungal communities in the Yellow River Delta, China. Compared to the native plant (Suaeda salsa), S. alterniflora invasion decreased the α-diversity of soil bacterial communities but did not affect that of fungal communities. The β-diversity of soil bacterial and fungal communities under S. salsa and S. alterniflora habitats also differed dramatically. S. alterniflora invasion increased the relative abundance of the copiotrophic phylum Bacteroidota, whereas decreased the relative abundances of the oligotrophic phyla Acidobacteriota and Gemmatimonadota. Additionally, the relative abundance of Chytridiomycota, known for its role in degrading recalcitrant organic matter, increased substantially within the soil fungal community. Functional predictions revealed that S. alterniflora invasion increased the relative abundance of certain soil bacteria involved in carbon and nitrogen cycling, including aerobic chemoheterotrophy, nitrate reduction, and nitrate respiration. More importantly, S. alterniflora invasion reduced the complexity and stability of both soil bacterial and fungal community networks. The shifts in soil microbial community structure and diversity were mainly induced by soil available nutrients and soil salinity. Overall, our study highlights the profound impacts of S. alterniflora invasion on soil microbial communities, which could further indicate the modification of ecosystem functioning by invasive species. [ABSTRACT FROM AUTHOR]

Global warming, elevated atmospheric CO2 concentrations and increased likeliness of extreme drought and wildfires in many regions will likely favour C4 grass species. To support future management actions, we explored the effect of the encroachment of an invasive perennial C4 grass, Sporobolus cryptandrus on the composition of soil seed banks in dry sand grasslands in Central Europe. In five mass‐locality sites of the species we assessed the composition and vertical segmentation of the soil seed bank in 12 1‐m2 plots along an increasing cover of the invasive species. We found that the seed bank diversity and density decreased with increasing sampling depth; the decrease in density was affected by the increasing S. cryptandrus cover. Neither the diversity nor the seed bank density of other species were affected by increasing S. cryptandrus cover but both were affected by the sampling site. Most of the studied seed bank characteristics were affected by the sampling depth, but none of them were affected by the increasing cover of S. cryptandrus. Increasing cover of S. cryptandrus in the vegetation was associated with an increasing proportion of S. cryptandrus seeds in the seed bank, and we found a low‐density soil seed bank of the species even in plots with no S. cryptandrus cover. Our finding that S. cryptandrus forms a massive soil seed bank, together with the predicted decrease in the precipitation of the summer months and increase in the frequency of droughts in the region, projects further rapid spread of the species. [ABSTRACT FROM AUTHOR]

Browsing by alien vertebrate herbivores can have both positive and negative impacts on plant invasion. We studied the European hare (Lepus europaeus) diet and foraging behavior focusing on interactions with two invasive non-native shrub species, Cytisus scoparius and Rosa rubiginosa. Fecal pellets were used for microhistological analysis of diet and seed identification. Foraging use of both species was evaluated by browsing rankings. The diet consisted of 28 items, predominating native grasses such as Poa spp. and Festuca pallescens. Among the non-native species, the grasses Hordeum spp. leaves and stems of the shrub C. scoparius, and seed fragments of Rumex acetosella, and rosehip stand out. Fecal pellets contained 431 whole seeds from nine plant species, predominating non-native species. In diet analysis, a portion of damaged rosehip seeds was observed; however, a significant number of viable seeds were previously extracted. This suggests that consumption of R. rubiginosa fruits contributes to seed dispersal, facilitating its spread. In contrast, the browsing of L. europaeus on the vegetative parts of C. scoparius juveniles significantly reduced their cover, which could slow their growth or prevent their spread. These results are an important input for management decisions to prevent or delay the spread of these invasive species. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) facilitate ecosystem functioning through provision of plant hosts with phosphorus (P), especially where soil P is limiting. Changes in soil nutrient regimes are expected to impact AMF, but the direction of the impact may depend on context. We predicted that nitrogen (N)‐only enrichment promotes plant invasions and exacerbates their P limitation, increasing the utility of AMF and promoting AMF diversity. We expected that enrichment with N, P and other nutrients similarly promotes plant invasions, but decreases the benefit and diversity of AMF because P is readily available for both native and exotic plants.We tested these hypotheses in eucalypt woodlands of south‐western Australia, that occur on soils naturally low in P. We evaluated AMF communities within three modified ground‐layer states representing different types of nutrient enrichment and associated plant invasions. We compared these modified states to near‐natural reference woodlands.AMF richness varied across ground‐layer states. The moderately invaded/N‐enriched state showed the highest AMF richness, while the highly invaded/NP‐enriched state showed the lowest AMF richness. The reference state and the weakly invaded/enriched state were intermediate. AMF richness and colonisation were higher in roots of exotic than native plant species.AMF community composition differed among ground‐layer states, with the highly invaded/NP‐enriched state being most distinct. Distinctions among states were often driven by family‐level patterns. Reference and moderately invaded/N‐enriched states each supported distinct groups of zero‐radius operational taxonomic units (zOTUs) in Acaulosporaceae, Gigasporaceae and Glomeraceae, whereas Gigasporaceae and Glomeraceae were nearly absent from the highly invaded/NP‐enriched state. Further, Diversisporaceae and Glomeraceae were most diverse in the moderately invaded/N‐enriched state.Synthesis. Both the nature of soil nutrient enrichment and plant provenance matter for AMF. N‐only enrichment of low‐P soils increased AMF richness, likely due to the introduction of AMF‐dependent exotic plant species and exacerbation of their P limitation. In contrast, multi‐nutrient enrichment, decreased AMF richness potentially due to a decrease in host dependence on AMF, regardless of host provenance. The changes in AMF community composition with nutrient enrichment and plant invasion warrant further research into predicting the functional implications of these changes. [ABSTRACT FROM AUTHOR]

The cherry laurel (Prunus laurocerasus) is a very popular garden plant and has been widely reported as a garden escape in Central Europe. However, it is still considered an unestablished neophyte in Germany. Few critical data are available on local population sizes, life history or reproductive biology outside its natural range. We carried out a study with 24 transects of 500 m × 6 m in the Kottenforst near Bonn, western Germany to fill these knowledge gaps. Along these transects we recorded the plant number and plant sizes and analysed their age structure. We found Prunus laurocerasus along 19 of 24 transects with up to 63 individual per transect. The largest plants covered areas of up to 50 m2 and were up to 30 years old. However, most of the plants were less than 20 years old and established since 2000. Since we observed high fruit set and old plants surrounded by many seedlings we conclude that Prunus laurocerasus has to be considered as an established neophyte in our study area and has invasive potential. [ABSTRACT FROM AUTHOR]

In the process of applying exotic plants to wetland ecological restoration, insufficiently evaluated alien species may exhibit strong competitiveness and fecundity. Once introduced, they can displace native flora, disrupt the original ecological balance, diminish biodiversity, and even induce ecosystem dysfunction. Furthermore, exotic plants have the potential to alter soil microbial community structure, including the composition and activity of beneficial symbiotic microorganisms such as arbuscular mycorrhizal fungi (AMF), thereby impacting soil nutrient cycling and interplant nutrient competition. Here, we conducted three consecutive years of sampling experiments to investigate the succession of AMF communities associated with the invasive plant Spartina alterniflora along an initial introduction chronosequence, and to identify the key environmental factors influencing its response to S. alterniflora invasion. Our findings reveal that early-stage invasion by S. alterniflora alters the composition of soil AMF communities with unclassified_c__Glomeromycetes and Glomus-viscosum-VTX00063 consistently dominating. Additionally, as the duration of introduction increases, the diversity of rhizosphere soil AMF significantly decreases, while its evenness remains relatively stable. It's indicated that soil ω, AN, AK and N/P ratio were the main influencing factors of the integral AMF community. Notably, soil available phosphorus (AP) emerges as a positive influence on the important AMF taxa. The results confirm the mutual feedback effect between the invasion of the perennial herb S. alterniflora and AMF, in which specific AMF assist in nutrient absorption to promote S. alterniflora growth, potentially facilitating its rapid and successful invasion of new habitats. Given the likely differential effects of AMF communities on various plant species, our findings could contribute to anticipating future AMF-mediated effects during the introduction of alien plants. [ABSTRACT FROM AUTHOR]

Aim: Invasive plants may evolve a suite of distinctive traits during spread in the new range. Among these traits, dispersal ability is an important trait determining the invasion speed of exotic plants. There is evidence that higher dispersal ability is favoured at the invasion front, where population density may be low. However, no study has explicitly tested how planting density in a common garden affects the dispersal ability of invasive plants. Location: Hainan island of China. Methods: In this study, using 27 populations of an invasive plant, Mikania micrantha, which is expanding its range on Hainan island of China, we examine how three dispersal‐related traits (i.e. dispersal ability, fruit mass, and pappus radius) change with distance from invasion centre and field population density, and how planting density in a common garden affects dispersal traits. Results: Dispersal traits did not change with distance from the invasion centre and field population cover either in the natural environment or in the common garden. In the common garden, increasing planting density from one to five plants per pot increased fruit mass and decreased dispersal ability, indicating that the effect of density on dispersal traits could not be detected in the field. The relationship between dispersal ability in the natural environment and that in the common garden was positive but significant only under the five plants per pot treatment, possibly because dispersal traits in natural conditions were selected under high‐density growth conditions. Main Conclusions: Our results indicate that increasing population density may increase fruit mass and reduce the dispersal ability of range‐expanding invasive plants. We suggest that further studies exploring the patterns of dispersal traits in range‐expanding invasive plants in a common garden should consider intraspecific competition. [ABSTRACT FROM AUTHOR]

Ecological study on plant diversity and soil characteristics of two contrasting sites (Prosopis juliflora-invaded and non-invaded) in Hastinapur Wildlife Sanctuary was undertaken to understand the structure of vegetation and soils and implication of exotic dominance in a dry tropical region of India. Seasonal floristic composition was recorded for one year through monthly visits. Phytosociological study of the two sites in each of three seasons was carried out by sampling a total of 120 quadrats (each 1mx1m, n= 20×3×2). Plant species density and abundance was estimated for both sites in each season. Seasonal surface soil (0-10 cm) samples were analyzed for soil pH, moisture content, organic C, and total N. Species occurrences and their relative abundance data were used to estimate alpha and beta diversity. A total of 76 plant species from 29 families were recorded (Malvaceae, Fabaceae and Asteraceae being top dominants). Maximum flora was recorded in rainy season at both sites, higher at non-invaded sites in all seasons. Beta diversity followed similar trend, higher in rainy season and at non-invaded than invaded sites, highest being 13.2 at non-invaded site in rainy season. Dominants changed with site and season. Vegetation patches were distinct in drier seasons compared to rainy months. Soil organic carbon, total nitrogen and C : N ratios were high at invaded sites compared to non-invaded sites except in summer season. While higher diversity and higher similarity amongst different sites in rainy season indicated a homogenization impact in Indian dry tropical regions, higher diversity at non-invaded site suggested implication of diversity-reducing impact of tree invader Prosopis juliflora. [ABSTRACT FROM AUTHOR]

Human landscape-transforming activities contribute to the global change in vegetation in different forms. Hunting is one of the most ancient human landscape-shaping activities. Feeders for hunting are particularly disruptive to vegetation. In the present study, we conducted a vegetation survey in these highly disturbed places. We investigated the vegetation dynamics over several years in the turkey oak–sessile oak zone, in two areas with different moisture and shade conditions (forest and clearing). Important background factors are the changes in precipitation and temperature. Our results confirm that weed infestation is detectable at bait sites over a long period. The seasonal changes in field weed vegetation, as well as the increase in the number and coverage of weed species at the end of summer, resulting from lifestyle characteristics, were generally detectable in all years and locations, especially in the case of open and more strongly degraded clearings. Meteorological factors played a role in the degree of weed infestation in each year. Degradation was more significant in drought years, while regeneration was also observed in wetter periods. At baits located in the clearing, we showed a positive correlation between the amount of summer precipitation and the total coverage of weed species, as well as between the average spring temperature and the coverage of certain weed species. With the drying of the climate, the disturbed areas are constantly losing their natural value, but wetter weather is not an automatic solution either. Considering that there are approx. 30,000 bait sites in the country, and they are used regularly and very intensively, they can serve as major infection hotspots for alien species in a network. [ABSTRACT FROM AUTHOR]

Introduction: The macrobenthos are crucial for the stability of estuarine ecosystems due to their burrowing behavior in the sediment and their uptake of nutrients from plants. These activities lead to significant alterations in both the morphological and biogeochemical processes within the region. Methods: However, there is limited investigation into carbon cycling processes specifically related to crab bioturbation. Additionally, few studies have examined enzymatic activities and carbon fractions in sediments from crab burrow walls at different crab growth stages. This study aims to explore the impact of both plant invasiveness and crab bioturbation on carbon storage. Results: Our findings suggest that plant invasion leads to higher organic accumulation due to the reduction of recalcitrant organic carbon (ROC) (decreased by 11.6% in invasive and 62.6% in native site from April to December), faster photosynthetic rates (25.8 μmol/m² s in invasive and 10.7 μmol/m² s in native site), and an increased presence of arbuscular mycorrhizal fungi (AMF) in the soil over time. However, the increase of easy oxidized carbon (EOC) may lead to less carbon storage in soil (increase by 67.7% in invasive and 48.8% in native site from April to December). In addition to invasiveness, the bioturbation activities of macrobenthos also affect carbon storage. Sediments from crab burrows exhibit higher EOC content (33.6% more than the bulk soil) and higher levels of carbon cycling-related enzymes, including S-ACT, S-β-GC, and S-ACP activities (24.2%, 8.99%, and 135.6% higher than the bulk soil, respectively). Discussion: These changes contribute to reduced carbon accumulation in the soil. Therefore, crab bioturbation is a more significant factor affecting carbon sink capacity than plant invasion. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: This research focused on the taxonomic filtering of terrestrial birds in plant invasion-altered landscapes. There were assessed changes in bird habitat assemblages (ground/herb dwellers, bush foragers, ecotone birds, and tree foragers) associated with a gradient of invasion on sites (far from the invasion, uninvaded although susceptible to invaders, and invaded) set in European agricultural lands. The results indicated the impact of invasion on two habitat assemblages of birds (i.e., ground/herb species loss and creating the distinctive bush species composition) and a decrease in the abundance and species diversity of birds from the whole community in the invaded areas. Describing the spatial distribution of communities is crucial to understanding how environmental disturbance can affect biodiversity. Agricultural lands are susceptible to disturbances of anthropogenic origin and have been identified as ecosystems of conservation concern. Such lands are vulnerable to invasions by anthropogenically introduced non-native plants disturbing habitats. This research focused on the invasion-induced taxonomic filtering of birds with shared habitat requirements. The birds were surveyed along a gradient of invasion-altered areas (far from the invasion, uninvaded although susceptible to invaders, and invaded) to identify changes in bird assemblages (ground/herb dwellers, bush foragers, ecotone birds, and tree foragers) caused by this disturbance. Data were collected from 112 sites sampled in southeastern Poland. There were significantly fewer bird species from each assemblage on invaded sites than on uninvaded sites, although exposed to invasion, despite the decrease in the abundance of only ground/herb dwellers. Beta diversity analysis showed that sites with invasion contained bird communities significantly different from those at other sites. Invasion-induced changes resulted in a significant reduction in the diversity of ground/herb dwellers in comparison with uninvaded sites and created a distinctive bush bird assemblage. This was most likely due to the transformation of the grassland layer and the thickening of the shrub layer by plant invaders, which resemble shrubs in morphology. The results indicated the filtering effect of invasion on bird species composition at the level of two habitat assemblages despite the decreases in bird abundance and species diversity of the whole community. [ABSTRACT FROM AUTHOR]

• We conducted a meta-analysis on 127 experimental studies of alien plant performance. • Alien plant species generally tend to have higher performance than natives. • Direction and magnitude of alien superiority depends on the performance measure. • Alien superiority depends on experimental design and number of study species. • A lack of studies on population growth limits our assessment of true superiority. Biological invasions are a major threat to biodiversity because of invasive alien species' high population growth rates and spread in new ranges. The inherent superiority hypothesis states that particular characteristics of alien species cause them to perform better than native species. Using a meta-analysis of 127 studies and more than 900 experimental observations comparing alien and native plant performance, we investigated, whether: (1) studies comparing alien and native performance generally support the inherent superiority hypothesis; (2) the direction and magnitude of superiority depend on the choice of performance measure; and (3) it depends on other aspects of the study design or species. We found that the inherent superiority hypothesis was overall supported, although the strength of this result depended on the chosen measure of effect size (a significant effect for the standardized mean difference SMD (Hedge's g) but not for the log response ratio LRR). Alien plant species were more likely to be found superior compared to natives if performance was measured in terms of growth, reproduction or response to natural enemies. Measuring survival or abundance was less likely to result in alien superiority, while for measurements of physiology and response to mutualists results were mixed. Furthermore, aspects of experimental design, selection and number of study species played an important role. We thus quantitatively showed across a broad range of conditions how choice of performance measure and experimental design affect the direction and magnitude of alien superiority found in small-scale studies. Furthermore, our review pointed out a lack of studies that assessed population growth as a direct determinant of true superiority. Conducting studies using performance measures relevant for superiority, while also considering other potentially important factors such as residence time, will shed more light on how common true alien superiority is and in which contexts it is to be expected. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: The invasive plant Flaveria bidentis (L.) Kuntze, known as the "ecological killer", poses a significant threat to the ecosystem stability due to its strong phenotypic plasticity and high fertility. Previous studies have reported a close relationship between plant invasion and soil microbial communities. This study aimed to gain a deeper understanding of the relationship between the invasion of F. bidentis, the diversity of soil microbial communities, and soil physiochemical properties. Methods: In this study, we established a common garden experiment by planting F. bidentis and Chenopodium ficifolium Sm. separately and mixed, in Lanfang, China. We analyzed microbial communities in both bulk soil and rhizosphere soil using the high-throughput sequencing technology. Results: The results showed that F. bidentis invasion significantly increased bacterial and fungal diversities in rhizosphere soil, irrelevant with or without the existence of native plant species. Meanwhile, F. bidentis increased the content of organic matter and ammonium nitrogen (NH4+) in bulk soil and decrease the content of NH4+ in rhizosphere soil. Significant correlations were observed between nitrogen contents or acid phosphatase and specific soil microbial communities. Conclusions: These results underly that regardless of competition with native plants, the invasion of F. bidentis alters soil physicochemical properties and increases microorganism community diversity. This study establishes a theoretical foundation for further research on the invasion mechanisms of F. bidentis and provides valuable references for other studies about F. bidentis. [ABSTRACT FROM AUTHOR]

Species invasion in salt marsh wetlands is known to disturb the balance of biotic and abiotic ecosystems (e.g., changing material exchange cycles and community structure). However, its influence on the morphological evolution of salt marshes is not yet understood in depth. This study investigates the long-term temporal and spatial distributions of an invasive plant (Spartina alterniflora) and its morphological characteristics in the Yangtze Estuary by remote sensing imagery interpretation, tidal creek extraction, regional statistical analysis, and proximity analysis. The invaded site shows an area of Spartina alterniflora with a 35-fold increase from the start to the end of its initiation phase; it is the second biggest species in the study area. It is found that species invasion not only limited the expansion of native pioneer vegetation but also changed bio-geomorphic feedback loops. With the influence of plant invasion, median tidal creek lengths decreased and the median tidal creek sinuosity ratio remained stable, between 1.06 and 1.07 in the subarea. The method used here is adaptable to other salt marshes. The findings from this study can provide practical guidance for the restoration of native salt marshes in the estuary and thus control the spread of invasive species. [ABSTRACT FROM AUTHOR]

Biocontrol is widely considered an effective management solution for mitigating the negative impacts of invasive alien plants (weeds). Globally, post-release evaluations to assess individual biocontrol programmes are generally lacking and there have been persistent calls within the biocontrol of weeds literature to increase the quantity and quality of post-release evaluation studies. South African biocontrol researchers have prioritised post-release evaluation studies, with a significant proportion of funding dedicated to this purpose. In this study we review post-release evaluations of weed biocontrol programmes in South Africa that have been published in the last ten years, discuss the different ways these evaluations have been conducted, and identify gaps for future research. Post-release evaluations have been conducted at different scales, including physiological changes within individual plants, plant growth parameters, plant population dynamics and landscape level changes. In most cases, the results of these studies indicated that biocontrol has reduced invasions according to these metrics. While the reduction in the invasion is assumed to alleviate negative ecological and socio-economic impacts, this is usually not directly measured. Evaluations of the socio-economic and ecosystem level benefits of biocontrol were limited to just a few examples on aquatic weeds. More studies that investigate the landscape, socio-economic and ecosystem level changes due to biocontrol are required, especially for terrestrial weeds, if the true scale of the benefits provided by biocontrol are to be understood. [ABSTRACT FROM AUTHOR]

Plant invasion and land reclamation have drastically transformed the landscape of coastal wetlands globally, but their resulting effects on soil organic nitrogen (SON) mineralization and nitrous oxide (N2O) production remain unclear. In this study, we examined 21 coastal wetlands across southern China that have undergone habitat transformation from native mudflats (MFs) to Spartina alterniflora marshes (SAs), and subsequently to earthen aquaculture ponds (APs). We determined the SON net mineralization rate and the presence of pertinent enzyme‐encoding genes, namely chiA, pepA, and pepN. The SON net mineralization rate increased by 46.7% following the conversion of MFs to SAs but decreased by 33.1% in response to the transformation of SAs to APs. Nevertheless, there was no significant difference in the estimated mineralization efficiency of soil microbes among the habitat types. The results of structural equation modeling showed that N‐mineralization gene abundance played a major role in regulating SON mineralization. Although less than 20% of the SON was estimated to be labile/semi‐labile, SON mineralization was important in sustaining soil N2O production, with 5.8% of the mineralized N being fed into N2O production. Overall, our findings showed that the presence of S. alterniflora increased both SON content and mineralization rate, which would in turn promote further proliferation of this exotic plant along the coast. The conversion of S. alterniflora marshes to APs partially mitigated the positive effects of exotic plant invasion on SON turnover. Key Points: Spartina invasion and aquaculture reclamation affected soil organic nitrogen (SON) mineralization ratesSON mineralization was strongly driven by substrate and functional microbial genesN2O production potential correlated significantly with SON mineralization [ABSTRACT FROM AUTHOR]

Plant invasions severely threaten natural ecosystems, and invasive plants often outcompete native plants across various ecosystems. Arbuscular mycorrhizal (AM) fungi, serving as beneficial microorganisms for host plants, can greatly influence the competitive outcomes of invasive plants against native plants. However, it remains unclear how AM fungi alter the competitive balance between native and invasive species. A competitive experiment was conducted using an invasive Eupatorium adenophorum paired with a native congener Eupatorium lindleyanum. Specifically, both species were inoculated with (M+) or without (M−) the fungus Glomus etunicatum under intraspecific (Intra‐) and interspecific (Inter‐) competition. Plant traits were measured and analyzed regarding the growth and nutrition of both species. The results exhibited that the AM fungus significantly increased the height, diameter, biomass, C, N, and P acquisition of both the invasive E. adenophorum and the native E. lindleyanum. The root mycorrhizal colonization and the mycorrhizal dependency of native E. lindleyanum were greater than those of invasive E. adenophorum. Under M+, the Inter‐competition inhibited the growth and nutrition of invasive E. adenophorum compared to the Intra‐ competition. Further, native E. lindleyanum exhibited higher competitiveness than invasive E. adenophorum in growth and nutrition. Meanwhile, the AM fungus significantly improved the competitiveness of native E. lindleyanum over invasive E. adenophorum. In conclusion, AM fungus improved the competitive advantage of native E. lindleyanum over invasive E. adenophorum in growth and nutrition, potentially contributing to native species competitively resisting the invasion of exotic species. These findings emphasize the importance of AM fungi in helping native plants resist the invasion of exotic plants and further contribute to understanding plant invasion prevention mechanisms. [ABSTRACT FROM AUTHOR]

Understanding the relationship between plant diversity and invasibility is essential in invasion ecology. Species‐rich communities are hypothesized to be more resistant to invasions than species‐poor communities. However, while soil microorganisms play a crucial role in regulating this diversity–invasibility relationship, the effects of plant competition mode and soil nutrient status on their role remain unclear. To address this, we conducted a two‐stage greenhouse experiment. Soils were first conditioned by growing nine native species separately in them for 1 year, then mixed in various configurations with soils conditioned using one, three, or six species, respectively. Next, we inoculated the mixed soil into sterilized substrate soil and planted the alien species Rhus typhina and native species Ailanthus altissima as test plants. We set up two competition modes (intraspecific and interspecific) and two nutrient levels (fertilization using slow‐release fertilizer and nonfertilization). Under intraspecific competition, regardless of fertilization, the biomass of the alien species was higher in soil conditioned by six native species. By contrast, under interspecific competition, the biomass increased without fertilization but remained stable with fertilization in soil conditioned by six native species. Analysis of soil microbes suggests that pathogens and symbiotic fungi in diverse plant communities influenced R. typhina growth, which varied with competition mode and nutrient status. Our findings suggest that the soil microbiome is pivotal in mediating the diversity–invasibility relationship, and this influence varies according to competition mode and nutrient status. [ABSTRACT FROM AUTHOR]

Rice paddies are wetland ecosystems recognized as important habitats for many organisms; however, the hybridization‐related extinction risk of native plant species has not been investigated in this system so far. Eclipta L. (Compositae) is a common paddy weed in Japan; however, its genetic composition might be altered due to the hybridization between the native E. thermalis and the closely related exotic E. alba. We examined Eclipta's genetic composition using 12 microsatellite markers (612 samples collected from 109 populations) and found (i) widespread geographical distribution of E. alba in Japan, (ii) hybridization with E. thermalis, and a large number of later‐generation hybrids, and (iii) widely varying situations among regions and populations. Eclipta alba appears to have invaded an open niche in northern Japan but has not yet reached southern Japan. Both E. alba and E. thermalis were found in central Japan; however, the latter had become rare due to hybridization‐mediated processes such as competition, and demographic and genetic swamping. Notably, endogenous and exogenous selection plays an important role in the invasion of E. alba, but to varying degrees among different areas. In summary, considering the genetic variability in E. thermalis, the genetic cluster of mainland Japan is in a highly critical situation due to the invasion of E. alba. [ABSTRACT FROM AUTHOR]

Critical and updated alien species inventories are crucial to properly manage and contrast biological invasions. After 6 years, a second update to the inventory of the vascular flora alien to Italy is presented. It provides details on the occurrence at administrative regional level and, for the first time, floristic data for San Marino. The checklist includes 1782 taxa (1673 species, 28 subspecies, 69 hybrids and 12 cultivar groups not attributable to a specific binomial), distributed in 786 genera and 159 families; 2 taxa are lycophytes, 13 ferns and fern allies, 37 gymnosperms and 1730 angiosperms. Among these, 154 taxa are archaeophytes and 1628 neophytes. The alien taxa currently established in Italy are 899 (649 naturalized and 250 invasive), while 796 taxa are casual aliens, 1 is not assessed, 38 have not been confirmed in recent times, 4 are considered extinct or possibly extinct in the country, 40 are doubtfully occurring in Italy, 4 are of unknown regional distribution and 110 are reported by mistake and to be excluded at national level. This checklist allows to establish an up-to-date number (10,023) of taxa currently constituting the whole (either native or alien) Italian flora. [ABSTRACT FROM AUTHOR]

Understanding why some, but not other, plant communities are vulnerable to alien invasive species is essential for predicting and managing biological invasions. Darwin proposed two seemingly contradictory hypotheses on how native‐invader relatedness influences invasion success, emphasizing, respectively, the importance of environmental filtering and competition between natives and invaders. Despite much recent empirical research on this topic, reconciling these two hypotheses, known as Darwin's naturalization conundrum, remains a challenge.Using plot‐level data from natural forests along elevational transects covering strong environmental gradients, we examined whether the invasion of the globally invasive species crofton weed (Ageratina adenophora) can be explained by environmental filtering and/or competition from closely related species linked to environmental gradients.Abundant precipitation, warm temperatures, open canopies and postfire environments facilitated A. adenophora invasion, whereas resident taxonomic richness suppressed its invasion. Importantly, we found that invader‐resident relatedness had a strong negative effect on invader cover under resource scarcity conditions (e.g. low water availability), but not under non‐resource environmental stress gradients (e.g. low temperature).Synthesis and applications. Our results suggest that the impact of species phylogenetic relatedness on invasion success varies distinctly along resource versus non‐resource environmental gradients. These results help to reconcile Darwin's naturalization conundrum, thereby improving the ability to predict the success of alien plant invasions in a changing world. Our study stresses the need to consider adjusting forest species composition to strengthen their resistance to invasion, while taking into account resource and non‐resource environmental gradients, particularly after wildfires. [ABSTRACT FROM AUTHOR]

The presence of alien plant species in disturbed habitats is a well‐studied subject, however, the contribution of wind farm projects to alien plant invasion is often overlooked in environmental impact assessment. The present study tests a survey method for the assessment of plant diversity and the detection of alien plant invasion in two wind farm areas in Romania. Over 5 years, we recorded plant species incidence data in disturbed and undisturbed plots, making one visit per growing season each year. Using several plant community indicators and methods, such as species richness, beta diversity, non‐metric multidimensional scaling, and multinomial species classification, we reliably detected plant species assemblage, including 26 alien plant species among the 608 recorded. Disturbed plots harbor a higher number of alien plant species, supporting the hypothesis that disturbances caused by wind farms reduce habitats' resilience to alien plant invasions. Despite the presence of habitat specialist plant species in certain plots, the community of alien plants did not show a clear preference for disturbed or undisturbed plots. The results underscore the importance of surveying the wind farms beyond the disturbed sites through regular monitoring to accurately assess their impact on plant diversity and detect alien plant invasions. The regular monitoring of all plant species during growing seasons will provide useful data for informing conservation strategies for native plants, including the control and eradication of alien species in early invasion stages. [ABSTRACT FROM AUTHOR]

Plants growing outside their native range may be confronted by new regimes of herbivory, but how this affects plant chemical defence profiles has rarely been studied.Using Plantago lanceolata as a model species, we investigated whether introduced populations show significant differences from native populations in several growth and chemical defence traits. Plantago lanceolata (ribwort plantain) is an herbaceous plant species native to Europe and Western Asia that has been introduced to numerous countries worldwide.We sampled seeds from nine native and 10 introduced populations that covered a broad geographic and environmental range and performed a greenhouse experiment, in which we infested half of the plants in each population with caterpillars of the generalist herbivore Spodoptera littoralis. We then measured size‐related and resource‐allocation traits as well as the levels of constitutive and induced chemical defence compounds in roots and shoots of P. lanceolata.When we considered the environmental characteristics of the site of origin, our results revealed that populations from introduced ranges were characterized by an increase in chemical defence compounds without compromising plant biomass. The concentrations of iridoid glycosides and verbascoside, the major anti‐herbivore defence compounds of P. lanceolata, were higher in introduced populations than in native populations. In addition, introduced populations exhibited greater rates of herbivore‐induced volatile organic compound emission and diversity, and similar chemical diversity based on untargeted analyses of leaf methanol extracts.In conclusion, the geographic origin of the populations had a significant influence on morphological and chemical plant traits, suggesting that P. lanceolata populations are not only adapted to different environments in their native range, but also in their introduced range. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Wolffia globosa is a small free-floating aquatic plant native to the Southeast Asia and invasive in Europe. Between the years 2017 and 2022 it has been found in Czechia for the first time in this country in wetland habitats at seven sites. Occurrences of alien W. globosa were first recorded in the Central Bohemia region inside the Site of Community Importance Libické luhy, then by two sewage treatment plants and one adjacent fishpond in South Bohemia and in the Elbe River near the cities of Přelouč, Lysá and Labem, Obříství and Hřensko. At four sites, W. globosa has been recorded in flowing waters for the first time in Europe. The mode of introduction remains unknown. [ABSTRACT FROM AUTHOR]

Tree holdings provide important socio-economic and environmental benefits, but invasive alien trees can constrain these benefits. However, some invasive alien plants provide both costs and benefits, making management complex due to varied stakeholder perceptions. Using household surveys, the study explored local people's perceptions of Acacia dealbata invasion and clearing in six villages located in upper Tsitsana communal areas, Eastern Cape Province of South Africa. The results suggest that most respondents are aware of A. dealbata invasion but not its invasion status. The respondents valued A. dealbata for its service provision including firewood, construction poles and shade but also cited negative impacts such as loss of grazing land and water. The respondents were aware of the Working for Water clearing programme and reported employment, income, and are awareness of restored grazing land and increased water availability as key clearing benefits. Although some respondents cleared A. dealbata in their homesteads, a small percentage were opposed to clearing due to the perceived loss of benefits. Overall, the study shows conflicting perceptions on the impacts of A. dealbata invasion and clearing, highlighting the value of considering the social dimensions of invasive alien plant species management to avoid conflict generation. [ABSTRACT FROM AUTHOR]

Biological invasions has caused significant damage to the ecological environment and economy of the world. Pest risk assessment is the most cost-effective means of preventing biological invasions to identify potentially suitable indexes for constructing pre-border weed risk assessment methods for China, we screened 80 metrics derived from 53 plant characteristics known to be related to invasive alien plants in other parts of the world and tested whether these metrics differed significantly between two groups of 103 invasive alien plants and 107 non-invasive plants in China. The results showed significant differences in 30 characteristics between invasive and non-invasive plants in China. Compared to the non-invasive plant group, the invasive plant group in China had a greater proportion of (1) plants native to the Americas, (2) plants belonging to the Asteraceae family, (3) polyploid plants, and had (4) a smaller proportion of plants propagated asexually only. The 30 metrics with significant differences were selected for LASSO regression to develop a predictive model to determine how well the metrics could distinguish between invasive and non-invasive alien plants already present in China. Finally an optimal model with 18 metrics was screened out. The optimal model was able to accurately discriminate 75% of non-invasive plants and 90% of invasive plants on the test set. Therefore the present study screened a range of useful metrics for the identification of invasive plants in China, and the high discriminative power of our models indicates that the subset of 18 variables retained in the final model could be useful for establishing a pre-border invasive plant screening tool for China in the future. [ABSTRACT FROM AUTHOR]

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The invasive plant Wedelia trilobata benefits in various aspects, such as nutrient absorption and environmental adaptability, by establishing a close symbiotic relationship with arbuscular mycorrhizal fungi (AMF). However, our understanding of whether AMF can benefit W. trilobata by influencing its metabolic profile remains limited. In this study, Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was conducted to analyze the metabolites of W. trilobata under AMF inoculation. Metabolomic analysis identified 119 differentially expressed metabolites (DEMs) between the groups inoculated with AMF and those not inoculated with AMF. Compared to plants with no AMF inoculation, plants inoculated with AMF showed upregulation in the relative expression of 69 metabolites and downregulation in the relative expression of 50 metabolites. AMF significantly increased levels of various primary and secondary metabolites in plants, including amino acids, organic acids, plant hormones, flavonoids, and others, with amino acids being the most abundant among the identified substances. The identified DEMs mapped 53 metabolic pathways, with 7 pathways strongly influenced by AMF, particularly the phenylalanine metabolism pathway. Moreover, we also observed a high colonization level of AMF in the roots of W. trilobata, significantly promoting the shoot growth of this plant. These changes in metabolites and metabolic pathways significantly affect multiple physiological and biochemical processes in plants, such as free radical scavenging, osmotic regulation, cell structure stability, and material synthesis. In summary, AMF reprogrammed the metabolic pathways of W. trilobata, leading to changes in both primary and secondary metabolomes, thereby benefiting the growth of W. trilobata and enhancing its ability to respond to various biotic and abiotic stressors. These findings elucidate the molecular regulatory role of AMF in the invasive plant W. trilobata and provide new insights into the study of its competitive and stress resistance mechanisms. [ABSTRACT FROM AUTHOR]

Numerous introduced species from cosmopolitan biogeographic origins have naturalized in the Hawaiian Islands and are spreading while native plant cover has declined. Phylogenetic, functional, and biogeographical diversity have been shown to influence invasion success, but relationships between these diversity measures and native plant abundance in invaded oceanic island forests have not been well established. Here we surveyed plant cover in 50 plots (400 m2) on the island of Oʻahu, Hawaiʻi. We measured four performance-related functional traits (specific leaf area, stem specific density, seed dry mass, and maximum plant height), and determined the growth form of each plant species. We calculated the differences between native and non-native community weighted mean trait values and assessed whether these differences, as well as measures of diversity, were associated with native and non-native cover. We found that average trait values were significantly higher for maximum height in natives, and significantly higher for specific leaf area and stem specific density in non-natives. A larger difference in maximum height between natives and non-natives was correlated with reduced non-native cover. Functional divergence and phylogenetic diversity of natives were positively correlated with native cover. Functional divergence and richness of non-natives were positively correlated with non-native cover. Biogeographical diversity was not significantly correlated with non-native cover but had indirect effects via its significant correlation with non-native functional richness, which was positively correlated with non-native cover. These findings suggest that diversity and competition for light may be important determinants of native and non-native species cover in invaded Hawaiian forests. An increasing number of distinct non-native plant introductions is thus likely to be associated with continued declines in native plant cover. [ABSTRACT FROM AUTHOR]

Microbes strongly affect invasive plant growth. However, how phyllosphere and rhizosphere soil microbes distinctively affect seedling mortality and growth of invaders across ontogeny under varying soil nutrient levels remains unclear. In this study, we used the invader Ageratina adenophora to evaluate these effects. We found that higher proportions of potential pathogens were detected in core microbial taxa in leaf litter than rhizosphere soil and thus leaf inoculation had more adverse effects on seed germination and seedling survival than soil inoculation. Microbial inoculation at different growth stages altered the microbial community and functions of seedlings, and earlier inoculation had a more adverse effect on seedling survival and growth. The soil nutrient level did not affect microbe-mediated seedling growth and the relative abundance of the microbial community and functions involved in seedling growth. The effects of some microbial genera on seedling survival are distinct from those on growth. Moreover, the A. adenophora seedling-killing effects of fungal strains isolated from dead seedlings by non-sterile leaf inoculation exhibited significant phylogenetic signals, by which strains of Allophoma and Alternaria generally caused high seedling mortality. Our study stresses the essential role of A. adenophora litter microbes in population establishment by regulating seedling density and growth.

Invasive alien species Alternanthera philoxeroides was found on Lake Biwa shore for almost two decades and has been causing huge loss for this region. This study aims at investigating three impact factors on reproduction of A. philoxeroides, namely nutrients, stem length, and stem diameter. Utilizing a ternary configuration dispersion method on 120 fragment samples collected from Lake Biwa shore after 10-days cultivation, the result indicates that nutrient salts significantly enhance growth (p < 0.01, Welch’s t-test), highlighting the species Epreference for eutrophic environments. Smaller stem fragments exhibit reduced growth, emphasizing the importance of thorough removal to minimize its persistence. Comparative analysis with Ludwigia grandiflora underscores that the latter exhibited bigger leaves under same experiment condition, and stem diameter significantly influence on its growth (37.7% contribution rate). These findings not only offer valuable references for elimination activities, but also stress the need for appropriate eradication strategies to preserve Lake Biwa’s aquatic ecosystem, contributing valuable insights to invasive species management in ecologically sensitive areas.

Bidens pilosa is recognized as one of the major invasive plants in China. Its invasion has been associated with significant losses in agriculture, forestry, husbandry, and biodiversity. Soil ecosystems play an important role in alien plant invasion. Microorganisms within the soil act as intermediaries between plants and soil ecological functions, playing a role in regulating soil enzyme activities and nutrient dynamics. Understanding the interactions between invasive plants, soil microorganisms, and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment. In this study, we conducted a systematic analysis focusing on B. pilosa and Setaria viridis, a common native companion plant in the invaded area. To simulate the invasion process of B. pilosa, we constructed homogeneous plots consisting of B. pilosa and S. viridis grown separately as monocultures, as well as in mixtures. The rhizosphere and bulk soils were collected from the alien plant B. pilosa and the native plant S. viridis. In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B. pilosa, we analyzed the effects of B. pilosa on the composition of soil microbial communities and soil ecological functions. The results showed that the biomass of B. pilosa increased by 27.51% and that of S. viridis was significantly reduced by 66.56%. The organic matter contents in the bulk and rhizosphere soils of B. pilosa were approximately 1.30 times those in the native plant soils. The TN and NO3– contents in the rhizosphere soil of B. pilosa were 1.30 to 2.71 times those in the native plant soils. The activities of acid phosphatase, alkaline phosphatase, and urease in the rhizosphere soil of B. pilosa were 1.98–2.25 times higher than in the native plant soils. Using high-throughput sequencing of the 16S rRNA gene, we found that B. pilosa altered the composition of the soil microbial community. Specifically, many genera in Actinobacteria and Proteobacteria were enriched in B. pilosa soils. Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities. Plant biomass, soil pH, and the contents of organic matter, TN, NO3–, TP, AP, TK, and AK were the main factors affecting soil microbial communities. This study showed that the invasion of B. pilosa led to significant alterations in the composition of the soil microbial communities. These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties. Some microbial species related to C, N and P cycling were enriched in the soil invaded by B. pilosa. These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants. They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B. pilosa. Overall, our research contributes to a better understanding of the complex interactions between invasive plants, soil microbial communities, and ecosystem dynamics.

Plant invasions can have major impacts on ecosystems, both above‐ and belowground. In particular, invasions by legumes, which often host nitrogen‐fixing symbionts (rhizobia), are known to modify soil bacterial communities. Here, we examined the effect of the invasive herbaceous legume Lupinus polyphyllus on the alpha diversity and community composition of soil bacteria. We also explored the relationships between these bacterial communities and vegetation cover, the cover of other (non‐invasive) legumes, or the number of vascular plants present. For this, we sampled rhizosphere soil and surveyed vegetation from ten paired sites (uninvaded versus invaded more than 10 years ago) in southwestern Finland, and identified bacterial DNA using 16S rRNA gene amplicon sequencing. The presence of the plant invader and the three vegetation variables considered had no effect on the alpha diversity of soil bacteria in terms of bacterial richness or Shannon and Inverse Simpson diversity indices. However, the composition of soil bacterial communities differed between invaded and uninvaded soils at four out of the ten sites. Interestingly, the relative abundances of the top bacterial families in invaded and uninvaded soils were inconsistent across sites, including for legume‐associated rhizobia in the family Bradyrhizobiaceae. Other factors—such as vegetation cover, legume cover (excluding L. polyphyllus), number of plant species—also explained a small proportion of the variation in bacterial community composition. Our findings indicate that L. polyphyllus has the potential to modify the composition of local soil bacterial community, at least in sites where it has been present for more than a decade. [ABSTRACT FROM AUTHOR]

Winter feeding of birds is one of the most widespread forms of human influence on animals in the world. Urban areas, however, contain many other food sources apart from the contents of feeders, including contaminated food and seeds of invasive plants. This research aimed to investigate whether birds exploring urban food select it, giving up potentially toxic or unknown seeds, or whether they use every available food. In the winter of the year 2022, an experiment was carried out with 18 feeders in two city parks in Kraków, Poland, which was based on feeding birds using sunflower seeds with various admixtures of the invasive Caucasian hogweeds Heracleum sp. seeds. Despite the detection of pecking marks on the hogweed seeds, only a small part of them disappeared from the feeders compared to the intensive feeding of birds on sunflower seeds. This result shows that not every new food source in the city can be used by birds. Urban explorers remain selective when choosing food, which keeps their behaviour close to non-urban populations. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to examine the effects of enhanced UV-B radiation, nitrogen addition and their interaction on the interspecific competition between invasive weed Alternanthera philoxeroides and its native accompanying species Digitaria sanguinalis, providing reference for the control of invasive plants under the global change.【Method】According to the de Wit substitution test method, we totally set two experimental factors that contained the treatment method（nitrogen addition, UV-B radiation, nitrogen × UV-B） and the species（A. philoxeroides, D. sanguinalis） on the mono and mixed potting cultures, measured the total biomass, morphology, pigment, and photosynthetic fluorescence of these two studied plant species, and then used the two-way ANOVA and the least significant difference（LSD） multiple comparisons to examine the differences of above indicators with different treatment combinations.【Result】（i） In the monoculture, nitrogen addition led to a significant increase in the maximum stem length of plants and leaf area of D. sanguinalis by 207.154% and 297.643%, and a significant decrease in the total biomass and qp＿Lss of A. philoxeroides by 40.612% and 52.381%, respectively. UV-B radiation led to a significant increase in the maximum stem length of plants, QY＿max and QY＿Lss of A. philoxeroides by 117.607%, 404.459% and 835.714%, respectively, and a significant decrease in the QY＿Lss of D. sanguinalis by 45.605%. The interaction effect led to a significant decrease in the total biomass of A. philoxeroides and QY＿max of D. sanguinalis by 79.310% and 18.984%, and a significant increase in the QY＿max of A. philoxeroides by 685.350%, respectively. The interaction effect also led to an opposite trade-off of F0 and QY＿Lss between these two studied plant species.（ii） In the mixed culture, nitrogen addition led to a significant increase in the leaf area and Chla of D. sanguinalis by 254.259% and 53.018%, respectively, and a significant decrease in the root length and Chla of A. philoxeroides by 76.051% and 12.084%, respectively. UV-B radiation led to a significant increase in the Chla of A. philoxeroides by 45.434%. The interaction effect led to a significant decrease in the root length of A. philoxeroides by 58.824%. 【Conclusion】Nitrogen addition relatively increased the competitive advantage of D. sanguinalis in terms of biomass and morphology, but UV-B radiation weakened its photosynthetic activity and increased the chlorophyll content of A. philoxeroides. Furthermore, UV-B radiation and its interaction with nitrogen addition significantly increased the actual photochemical efficiency of A. philoxeroides. Thus, we should strengthen the monitoring of A. philoxeroides invasion under global change, to prevent the interaction of multiple factors aggravating the competitive substitution of native plants by this invader. [ABSTRACT FROM AUTHOR]