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Abstract Effective ecological restoration requires detailed monitoring to determine the success achieved through different interventions in achieving objectives. In 2017, we resurveyed riparian sites along the Berg River in the Western Cape, South Africa, that have been cleared of invasive stands of Eucalyptus camaldulensis in 2010 using two clearing methods (fell-and-stackburn and fell-and-remove) and two restoration approaches: passive (where vegetation was allowed to recover without intervention) and active (assisted recovery). A significant increase in vegetation cover (P <.001) and diversity (P <.05) of native riparian species was recorded in passive restoration plots, but an increase in the cover of woody invasive alien plants was also observed. Only four of the nine native species that were planted to fast-track restoration were still present in the active restoration plots, but the abundance of these native species was significantly (P <.001) lower in 2017 than in 2011. We conclude that native vegetation recovery following E.camaldulensis removal seven years ago is following a positive recovery trajectory in both passive and active restoration sites, as shown by the increased occurrence of native trees and shrubs, e.g. Maytenus oleoides, Melianthus major and Searsia angustifolia which were not present before clearing. However, the reinvasion of cleared sites by woody invasive alien plants has the potential to slow down and potentially halt the recovery process. Further management interventions, e.g. removal of reinvading woody invasive alien plants, are required, emphasizing the sustained engagement to ensure restoration in these ecosystems. Highlights • Native vegetation recovery following E.camaldulensis removal is following a positive recovery trajectory. • Reinvasion of cleared sites by woody invasive alien plants has the potential to slow down the recovery process. • The removal of reinvading woody invasive alien plants is required to ensure ecological restoration success. [ABSTRACT FROM AUTHOR]

The establishment and spread of plants in their native or alien geographical ranges are determined by their germination. This study investigated the impact of different factors on variations in cardinal temperatures. We used the lm procedure and measured the effect size by the Eta-square approach to find the association of different factors (species, ecotypes, origin (native/alien), year, and life cycle) with the cardinal temperatures of 31 species. Our results showed that the base, optimum, and maximum temperatures responded differently to these factors. The base temperature was less impacted by ecotypes compared with the optimum and maximum temperatures, whereas the species had a higher impact on the variation in the base temperature. The effect of the origin of weedy plants on the base temperature was higher than the optimum and maximum temperatures. The effect of the year on the optimum temperature was more prominent than that on the base and maximum temperatures. The results confirmed that weedy alien plants preferred high and narrow ranges of base, optimum, and maximum temperatures and probably will be more problematic in summer crops. The results indicate that alien plants can benefit from warmer conditions in invaded areas at the germination stage. These findings lay the foundation for further studies to elucidate which factors are more important. [ABSTRACT FROM AUTHOR]

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Invasive alien plants (IAPs) present a severe threat to native ecosystems and biodiversity. Comprehending the potential distribution patterns of these plant invaders and their responses to climate change is essential. Parthenium hysterophorus, native to the Americas, has become an aggressively invasive species since its introduction to China in the 1930s. This study aims to collect and reconstruct the historical occurrence and invasion of P. hysterophorus. Using the optimal MaxEnt model, the potential geographical distributions of P. hysterophorus were predicted based on screened species occurrences and environmental variables under the current and three future scenarios in the 2030s, 2050s, and 2070s (i.e., SSP1-2.6, SSP2-4.5, and SSP5-8.5), and the invasion risk of P. hysterophorus in Chinese cities, croplands, forests, and grasslands was assessed. The results show that: (1) The species initially invaded highly suitable areas and further spread to regions with non-analogous climate conditions. (2) Under the current climatic conditions, the overall potential distribution of P. hysterophorus is characterized by more in the southeast and less in the northwest. Climate variables, including mean annual temperature (bio1), precipitation in the wettest month (bio13), isothermality (bio3), and temperature seasonality (bio4), are the primary factors influencing its distribution. (3) The potential distribution of P. hysterophorus will expand further under future climate scenarios, particularly toward higher latitudes. (4) Forests and crop lands are the areas with the most serious potential invasion risk of P. hysterophorus. Therefore, we suggest that the government should strengthen the monitoring and management of P. hysterophorus to prevent its spread and protect agro-ecosystems and human habitats. Depending on the potential risk areas, measures such as quarantine, removal, and publicity should be taken to mitigate the threat of P. hysterophorus invasion and to raise awareness of P. hysterophorus invasion prevention. [ABSTRACT FROM AUTHOR]

Invasive alien plants represent one of the five major threats to biodiversity and the disruption of ecosystems. They are introduced through various routes, starting with commercial trade. Preventing their introduction is essential to avoid the spread of new invasive plants. In this paper, we propose a new early warning DNA barcoding tool for invasive plant detection. Eight invasive alien species of European Union concern (i.e., Ludwigia grandiflora, Elodea nuttallii, Myriophyllum aquaticum, Pontederia crassipes, Ailanthus altissima, Heracleum mantegazzianum, Impatiens glandulifera, Pueraria montana) were selected and analysed. A unique DNA marker for each species was identified and amplified using species-specific primers capable of identifying the presence of alien species. To verify whether the approach could detect the presence of alien plants in urban areas from lawn clippings, mixes with typical urban spontaneous plants and invasive species were tested. In all mixes, only the invasive species was identified. This rapid detection capability will enable environmental operators to intervene promptly to contain the spread of invasive plants before they can cause significant damage to the local ecosystem. This tool could have a significant impact on the protection of local biodiversity and the integrity of urban habitats. [ABSTRACT FROM AUTHOR]

While invasive success of alien plant species is often attributed to their superior competitive abilities, it is also suggested that competitive ability depends on the target species of competition and resource availability. In addition, it remains unclear whether invaders and co‐occurring plants in the introduced area exhibit distinctive inter‐ and intraspecific competitive intensities. This study aimed to evaluate the competitive ability of a successful invader, Lactuca serriola, through a combination of field surveys and a growth chamber experiment. First, we assessed biodiversity and the biomass of co‐occurring plants in both L. serriola‐invaded and uninvaded plots across nine sites in South Korea. Subsequently, a pairwise competition experiment was conducted between L. serriola and three weedy plant species commonly found in the invaded plots, Chenopodium album, Erigeron canadensis, and Oenothera biennis, under differential nutrient levels. Diversity indices of plant communities and the biomass of most co‐occurring plants showed no significant difference between invaded and uninvaded plots. L. serriola and testing weedy plants exhibited mutually negative effects on biomass when grown together in the same pot, with the intensity of interspecific competition being comparable across nutrient treatments. Notably, intraspecific competition of L. serriola was weaker than testing weedy plants, particularly manifest in the high‐nutrient treatment. The results of both field and growth‐chamber studies demonstrated that L. serriola was not a particularly strong competitor compared to its neighboring weedy plants. Its successful invasion can be partially attributed to its weak intraspecific competition intensity, which potentially facilitate successful establishment with high density. [ABSTRACT FROM AUTHOR]

Invasive alien plant species (IAPS) pose a serious threat to overall plant biodiversity across the globe. Nepal's national parks and protected areas are not devoid of the impact of IAPS. Unfortunately, there is a substantial gap in knowledge regarding the extent and impact of invasion in protected areas of Nepal. This study assessed the impact of invasive alien plant species on the resident plant species of the Koshi Tapu wildlife reserve. After a preliminary field observation, we selected five major IAPS in the area, Mesosphaerum suaveolens, Chromolaena odorata, Ipomoea carnea, Lantana camara, and Mikania micrantha for this study. Ten pairs of adjacent plots sized 4 m × 4 m were surveyed for each invasive species, comprising diverse vegetation types. Each pair consisted of one "invaded plot" where the invasive species was dominant with cover greater than 50%, and another "uninvaded plot" laid out in an adjacent area with similar site conditions but without the invasive species. We calculated the Sørensen Index of Similarity for each paired plot. Wilcoxon rank‐sum test was employed to compare ecological parameters between invaded and uninvaded plots for various plant species. Similarly, the difference in impact between each of the five invasive species was assessed using the Kruskal–Wallis test. Species richness varied significantly between invaded and uninvaded plots for C. odorata and I. carnea. The most significant impact on species composition of invaded communities (39.6%) was observed for C. odorata. The cover of the other dominant species varied significantly between invaded and uninvaded plots for all five species studied. The Kruskal–Wallis test showed no significant difference in the impact caused by the five studied invasive species on Species richness, Shannon–Wiener diversity index, species evenness, and height of dominant species. However, a significant difference was observed between the impacts of five studied invasive species and the cover of other dominant species. The crown cover of dominant species decreased much more in the invaded plots of L. camara and M. micrantha than in other species. Specialized management efforts are required to control highly invasive species, such as C. odorata and I. carnea, alongside proactive measures to prevent further spread in ecologically sensitive areas. [ABSTRACT FROM AUTHOR]

Invasive alien species are considered a major contributor to biodiversity loss. Yet, many are favoured for particular ecosystem services that they provide. This is often so in urban environments experiencing rapid environmental and social change and land transformation. Public support is viewed as critical for invasive alien species prevention and management. Furthermore, it is assumed that local citizens are more likely to be willing and ready to engage if they are informed about the costs and benefits associated with invasive alien species. However, the use of, and attitudes towards, invasive alien species in urban areas is poorly understood, especially regarding urban gardens under private ownership and control. This lack of understanding is likely to compromise potential management interventions.Here, we report on a survey of 240 people across 12 small towns in the Eastern Cape province of South Africa to determine their knowledge and perceptions regarding woody invasive alien plants (IAPs), their willingness to engage in control and how these vary in relation to respondent attributes.The findings indicated that respondents have low levels of knowledge about woody IAPs despite 84% of them having at least one woody IAP species in their garden. Nineteen different woody IAPs were noted across the sample of 240 households. A wide range of ecosystem services and disservices from woody IAPs were mentioned. Because of the benefits provided, or the effort required to remove them, only 56% of respondents were willing to have the woody IAPs removed from their gardens, with most considering it the responsibility of government agencies to do so. There was a positive association between the levels of education, income, and the impression that woody IAPs pose a problem and being aware of the term, but not willingness to remove them.Synthesis and implications. These results reveal the complex relationship that urban citizens have with IAPs in garden settings, and for authorities to consider appropriate and targeted awareness campaigns if control strategies are to be successful. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Urban protected biodiversity areas conserve some of the world's critically endangered and isolated biodiversity while providing essential ecosystem services. However, these urban habitats are threatened by the presence of alien and invasive plants. We studied alien plant species richness and identified the potential predictors in urban protected biodiversity areas in Tshwane Metropolitan Municipality, South Africa. Data on alien plant species were collected through surveys and consultations with protected area managers. We determined the relationship between the observed species richness and potential alien plant species predictors, such as area size, number of visitors, proximity to residential areas, and the year the reserve was proclaimed. We documented 574 records of 189 alien plant species from 60 families across 14 protected areas. Phanerophytes were the most common (46.5%), with many species native to South America, North America, and Africa. Most species have formed naturalised populations (67.7%), followed by invasive populations (20.6%) and casual populations (12%), posing future invasion threats. Most species (55.5%) were introduced as ornamental plants, with many of these species forming invasive populations. Half the recorded species were listed under the NEM:BA A&IS regulations, mostly categorized as 1b. Our findings indicate that the annual number of visitors strongly predicted alien plant species richness in urban protected areas. Additionally, a significant negative correlation was observed between species richness and the proximity to residential areas and years since the proclamation. Understanding the distribution patterns and predictors of species richness is crucial in monitoring invasive alien species and conserving biodiversity in urban environments. [ABSTRACT FROM AUTHOR]

Introduction: Freshwater ecosystems are susceptible to invasion by alien macrophytes due to their connectivity and various plant dispersal vectors. These ecosystems often experience anthropogenic nutrient enrichment, favouring invasive species that efficiently exploit these resources. Propagule pressure (reflecting the quantity of introduced individuals) and habitat invasibility are key determinants of invasion success. Moreover, the enemy release hypothesis predicts that escape from natural enemies, such as herbivores, allows alien species to invest more resources to growth and reproduction rather than defense, enhancing their invasive potential. Yet, the combined impact of propagule pressure, herbivory, and nutrient enrichment on the competitive dynamics between invasive alien macrophytes and native macrophyte communities is not well understood due to a paucity of studies. Methods: We conducted a full factorial mesocosm experiment to explore the individual and combined effects of herbivory, nutrient levels, propagule pressure, and competition on the invasion success of the alien macrophyte Myriophyllum aquaticum into a nativemacrophyte community comprising Vallisneria natans, Hydrilla verticillata, and Myriophyllum spicatum. This setup included varying M. aquaticum densities (low vs. high, simulating low and high propagule pressures), two levels of herbivory by the native snail Lymnaea stagnalis (herbivory vs no-herbivory), and two nutrient conditions (low vs. high). Myriophyllum aquaticum was also grown separately at both densities without competition from native macrophytes. Results: The invasive alien macrophyte M. aquaticum produced the highest shoot and total biomass when simultaneously subjected to conditions of high-density intraspecific competition, no herbivory, and low-nutrient availability treatments. Moreover, a high propagule pressure of M. aquaticum significantly reduced the growth of the native macrophyte community in nutrient-rich conditions, but this effect was not observed in nutrient-poor conditions. Discussion: These findings indicate that M. aquaticum has adaptive traits enabling it to flourish in the absence of herbivory (supporting the enemy release hypothesis) and in challenging environments such as intense intraspecific competition and low nutrient availability. Additionally, the findings demonstrate that when present in large numbers, M. aquaticum can significantly inhibit the growth of native macrophyte communities, particularly in nutrientrich environments. Consequently, reducing the propagule pressure of M. aquaticum could help control its spread and mitigate its ecological impact. Overall, these findings emphasize that the growth and impacts of invasive alien plants can vary across different habitat conditions and is shaped by the interplay of biotic and abiotic factors. [ABSTRACT FROM AUTHOR]

Forests are important ecosystems that face threats from climate change and global environmental shifts, with invasive alien plant species being a significant concern. Some of these invasive species have already become established, while others are in the process of naturalisation. Although forests are a relatively stable ecosystem, extreme weather events increase their vulnerability to change, and clearings left after natural disturbances are particularly susceptible to invasion by alien plant species (IAPS). We created risk maps of two species that have spread rapidly in the last decade: American pokeweed (Phytolacca americana) and the tree of heaven (Ailanthus altissima). We prepared a generalised linear model based on the occurrence data collected within the LIFE ARTEMIS project. Eleven environmental variables were used to determine habitat characteristics. We constructed two models for each species: one covering the entirety of Slovenia and the other specifically for the forested areas in Slovenia, with the latter incorporating forest-specific variables (such as forest sanitation felling and monocultures). We observed the presence of both species at lower altitudes and in close proximity to water sources. American pokeweed tends to occur nearer to railways, while the presence of the tree of heaven is associated with areas lacking carbonate parent material and influenced by land use patterns. In forested areas, the occurrence of American pokeweed is influenced by forest habitat characteristics, such as disturbances caused by extreme weather events or the prevalence of Norway spruce monocultures. In contrast, the occurrence of the tree of heaven is influenced by more general environmental variables, such as altitude and proximity to railways. Consequently, we have generated risk maps for the entirety of Slovenia and separately for forested areas, both of which indicate similar levels of risk, particularly for the tree of heaven. The risk map for American pokeweed highlights numerous vulnerable areas, especially forest edges, which are highly susceptible to invasion. Furthermore, there is a higher likelihood of this species occurring in areas that have undergone sanitation felling. This study suggests that the production of risk maps of IAPS could be improved by focussing on habitat types and taking into account habitat-specific variables. This approach could enhance the early detection and management of these invasive species. [ABSTRACT FROM AUTHOR]

Preserving the dwindling native biodiversity in urban settings poses escalating challenges due to the confinement of remaining natural areas to isolated and diminutive patches. Remarkably scarce research has scrutinised the involvement of institutions, particularly universities, in introducing alien plant species in South Africa, thus creating a significant gap in effective monitoring and management. In this study, the Tshwane University of Technology in Tshwane Metropole, South Africa serves as a focal point, where we conducted a comprehensive survey of alien plants both within the university premises and beyond its confines. The investigation involved the classification of invasion status and a meticulous assessment of donor and recipient dynamics. Our findings encompass 876 occurrence records, revealing the presence of 94 alien plant species spanning 44 distinct families. Noteworthy occurrences among the dominant plant families are Asteraceae and Solanaceae. Herbaceous and woody plants emerged as the most prevalent alien species, with common representation across both sampling sites. A substantial majority of recorded species were initially introduced for horticultural purposes (51%) before escaping and establishing self-sustaining populations (62%). Furthermore, 43 species identified are listed in South African invasive species legislation, with some manifesting invasive tendencies and altering the distribution of native species in the remaining natural areas. The notable overlap in species observed between the university premises and adjacent areas provides crucial insights into the influence of institutions on the dynamics of plant invasions within the urban landscape. This underscores the prevailing gaps in the management of invasive alien plants in urban zones and accentuates the imperative of an integrated approach involving collaboration between municipalities and diverse institutions for effective invasive species management in urban environments. [ABSTRACT FROM AUTHOR]

Invasive alien plants (IAPs) have serious environmental and economic impacts, especially in vulnerable areas of China. However, IAP richness distribution patterns, their driving factors, and the dynamic shifts in potential distribution areas remain elusive. We assessed IAP richness distribution patterns and drivers using 402 IAPs recorded in China at 88 926 occurrence points, and then predicted their potential distribution areas. The results show that IAP hotspots were mainly located in southeastern China, especially coastal areas of the South and East and large inland cities. Population density, gross domestic product (GDP), and four climate variables associated with precipitation and temperature jointly influenced the richness distribution pattern of all IAPs. Specifically, population density and GDP impacted the richness distribution pattern of narrow‐range IAPs, and population density, GDP, distance to the nearest national highway, and five climate variables affected the richness distribution pattern of widespread IAPs. Only GDP contributed significantly to the richness distribution pattern of the top 5% hotspot grid cells, whereas population density, GDP, and precipitation in the driest month (BIO14) significantly influenced the richness distribution patterns of hotspots for both the top 10% and top 20%. Prediction analysis demonstrated that southeastern China would have particularly high invasion risk under both current and future climate scenarios. Regions with increases in predicted species richness are more common (44.83–64.97%) than those with decreases, except under the Representative Concentration Pathway (RCP) 4.5 scenario. Climate change will contribute greatly to the expansion of potential IAP distribution areas under both optimistic (RCP 2.5) and pessimistic scenarios (RCP 8.5). The results of this study provide insights into the priority management of IAPs by developing promising strategies for the control and prevention of IAP invasion. [ABSTRACT FROM AUTHOR]

Urbanization is a major form of landscape alteration characterized by the extent of impervious structures. For urban vegetation, dispersal is key for allowing plants to reach and occupy spaces that offer conditions for germination. Here, we investigated (i) the effect of urbanization intensity on the variation in plant height, quantity, size and weight of fruits and seeds of spontaneous plants; (ii) the presence of variation in the traits for species with different dispersive syndromes and invasion status; and (iii) the effect of urbanization on the proportion of species with different dispersive syndromes. We collected plants from the herbaceous and shrub strata in different intensities of urbanization, in Lavras-MG, Brazil. Data were analyzed using generalized linear mixed-effect models. A total of 88 plant species were identified. We observed a decrease in the values of the functional traits with increasing urbanization intensity. Plant height decreased with increased urbanization. Anemochorous plants showed a decrease in fruit size, and zoochoric plants showed a decrease in fruit and seed weight. There was a reduction in the number and size of fruits of native plants and in the number of seeds of naturalized exotic plants. There was no variation in the proportion of species by dispersive syndromes. The tendency of smaller dispersive structures illustrates the filtering of functional traits caused by urbanization. [ABSTRACT FROM AUTHOR]

The assessment of seed banks could provide useful hints towards ensuring restoration planning and invasive species management. In this study, the impacts of two invaders such as Hyptis suaveolens and Urena lobata on the soil seed banks were investigated. We also assessed the seed characteristics of the invaders at the invaded sites. This was achieved using 10 sites each for H. suaveolens- and U. lobata- invaded habitats and -non-invaded habitats making a total of 30 sites. We collected 200 soil samples from each habitat type. A seedling emergence method was used to determine the seed bank recruitment of both invasive plants. The diversity indices of the above-ground vegetation of sites invaded by the two plants were significantly lower than those of the non-invaded sites. Only two plant species emerged from the seed banks of H. suaveolens and five plants from those of U. lobata when compared with non-invaded sites where 53 species emerged. A larger portion of the seeds was located in the soil's lower layer at all the sites invaded by H. suaveolens while those of U. lobata and non-invaded sites were found in the upper layers and there are significant associations between the habitats. The lower soil layers of the two species have the highest percentage of viable seeds. These results help us to understand more about the invasiveness of both species as related to their impacts on the seed banks and native vegetation. It also indicates that the native species that emerged from the invaded seed banks could be used for the restoration of the invaded habitats. [ABSTRACT FROM AUTHOR]

Plantations, and associated invasions, of exotic Pinus trees occur extensively in the southern hemisphere, threatening the persistence of biodiverse Mediterranean‐climate vegetation. Large‐scale decommissioning of such plantations in the eastern Cape Floristic Region (South Africa) enabled a wide‐ranging study showing successful passive restoration of fynbos vegetation after afforestation. Using a paired study design, we compared the diversity, and floristic and growth‐form composition of post‐fire recovering fynbos in former plantations with that in recently burnt neighboring fynbos in a natural state within the Garden Route National Park. The fynbos of the study area showed good autogenic recovery after several decades of pine afforestation and a fire subsequent to the clearcutting of these trees. On average, native plant abundance and species richness (particularly of shrubs) were significantly lower, and non‐native plant species richness significantly higher, in former plantation areas than in natural fynbos, but these differences were small. Species diversity (Shannon–Wiener index) did not differ significantly between the two vegetation states. The former plantations harbored 91% of the number of native species that the natural fynbos had, while the similarity of the two floras was 65%. Non‐metric multidimensional scaling ordination and multivariate generalized linear models accordingly showed no clear distinction in community composition between the two vegetation states. We concluded that the restoration potential of the montane grassy fynbos in the study area is superior to that previously documented in montane proteoid fynbos, and that fire and invasive alien plant control after clearcutting of the plantations is essential to promote fynbos restoration. [ABSTRACT FROM AUTHOR]

Management of invasive alien plants is an increasing problem throughout the world. In some cases native rare or protected species can appear or even prefer habitats dominated by invasive alien plants, which raises questions about the optimal treatment of such areas. Erythronium dens-canis in Hungary is a protected species which only have several occurrences in the country and a number of these populations situated in Robinia pseudoacacia stands developed after harvesting native forests. In this study a total of five populations of E. dens-canis were surveyed between 2020 and 2022 in southwestern Hungary examining and comparing the ongoing demographic changes under native and Robinia stands by monitoring individual plants. Two populations were situated in forests composed of native tree species, two in Robinia pseudoacacia-dominated stands and one in a Robinia-native tree species mixed stand. We categorized the plants into five age-state categories: dormant, seedling, juvenile, vegetative adult, and reproductive adult. We found some considerable differences (e.g. leaf size, reproduction rate) between the populations situated in native and in Robinia stands, whereas the population in mixed forest showed intermediate character in most examined factors. Based on our results, R. pseudoacacia have a significant effect on the phenology and life history of E. dens-canis, and this effect is greater with higher proportion of R. pseudoacacia in a forest stand where the E. dens-canis occurs. [ABSTRACT FROM AUTHOR]

The invasion of alien plant species threatens the composition and diversity of native communities. However, the invasiveness of alien plants and the resilience of native communities are dependent on the interactions between biotic and abiotic factors, such as natural enemies and nutrient availability. In our study, we simulated the invasion of nine invasive plant species into native plant communities using two levels of nutrient availability and suppression of natural enemies. We evaluated the effect of biotic and abiotic factors on the response of alien target species and the resistance of native communities to invasion. The results showed that the presence of enemies (enemy release) increased the biomass proportion of alien plants while decreasing that of native communities in the absence of nutrient addition. Furthermore, we also found that the negative effect of enemy suppression on the evenness of the native community and the root‐to‐shoot ratio of alien target species was greatest under nutrient addition. Therefore, nutrient‐poor and natural enemies might promote the invasive success of alien species in native communities, whereas nutrient addition and enemy suppression can better enhance the resistance of native plant communities to invasion. [ABSTRACT FROM AUTHOR]

Rising temperatures due to climate change are expected to interplay with biological invasions, and may enhance the spread and growth of some alien species upon arrival in new areas. To successfully invade, a plant species needs to overcome multiple biological barriers. Among the crucial life stages, seed germination greatly contributes to the final species assembly of a plant community. Several studies have suggested that alien plant success is related to their high seed germination and longevity in the soil. Hence, our aim is to test if the germination potential of alien seeds present in the seed bank will be further enhanced by future warming in temperate dry grasslands, an ecosystem that is among those most prone to biological invasions. We designed a laboratory germination experiment at two temperatures (20 and 28 °C), to simulate an early or late heat wave in the growing season, using seeds from nine common grassland Asteraceae species, including native, archaeophyte and neophyte species. The test was performed on both single and mixed pools of these categories of species, using a full-factorial orthogonal design. The warmer germination temperature promoted neophyte success by increasing germination probability and germination speed, while negatively impacting these parameters in seeds of native species. The co-occurrence of native and archaeophyte seeds at the lower temperature limited the invasiveness of neophytes. These results provide important information on future management actions aimed at containing alien plant invasions, by improving our knowledge on the possible seed-bank response and interaction mechanisms of common species occurring in disturbed natural areas or restored sites. Summary of the experimental results. The colour of the flowers represent the status, divided as native (blue), neophyte (red) and archaeophyte (green). Each flower symbol represents the species pool for each plant category (i.e. NA = Buphthalmum salicifolium, Carlina vulgaris, Centaurea scabiosa; NE = Artemisia annua, Symphyotrichum novi-belgii, Senecio inaequidens; AR = Centaurea cyanus, Cichorium intybus, Tripleurospermum inodorum). The number of flowers represent the germination percentage of the various category assembly. In the columns are divided the various combination. From up to bottom the trend of germination percentage at 20 and 28 °C are shown. [ABSTRACT FROM AUTHOR]

1. The invasion of alien plants into natural ecosystems in South Africa is a substantial conservation concern. The primary reason for the introduction of alien plants has been ornamental horticulture, and urban centres are the main sources of invasions. Small towns have high edge: area ratios which favour the launching of invasions into surrounding areas. There is, however, a shortage of information at the global and local scale on the occurrence, distribution, and status of alien plants in an urban context. 2. We surveyed all alien plants in the small town of Riebeek Kasteel in the Western Cape, South Africa, to gain insights on where to find alien plant species, and to assist with future studies and the management of alien floras in small towns. 3. We surveyed publically accessible land, recording the abundance of all alien plant species every 10 m of road. A species accumulation curve was compiled to show the rate at which new species were encountered. This approach was used to test the efficacy of different sampling strategies. 4. Two hundred and ninety eight alien plant taxa were recorded in five land-use types. Half of the alien plant species recorded were naturalised within the town, while a third were invasive in the region (the Berg River catchment). 95% of the taxa, including many invasive species, occurred in gardens or adjoining road-sides, highlighting the invasion risk posed by ornamental horticulture. The most efficient way of collecting data on alien plant distribution for this town would have been to survey roads in the town centre first, rather than urban-edge roads and industrial areas. 5. Synthesis and applications: The gardens of small towns in South Africa harbour a high diversity of alien plants, many of which are already invasive or are potentially invasive. As the alien flora differs markedly between gardens, it is difficult to extrapolate generalised rules of thumb on where to survey. This means that compiling accurate inventories of alien plants in urban areas requires substantial search effort and taxonomic expertise. [ABSTRACT FROM AUTHOR]

To understand the alien plant invasion patterns, it is important to know if their consequences are equal in different regions, particularly in different parts of the secondary range. In this article, we estimated plant species richness in communities invaded by the North American tree Acer negundo L. in two remote regions: the Belarusian Polesia and the Middle Urals. We tested three hypotheses about: (1) decreased plant species richness in communities invaded by A. negundo; (2) presence of alien species in invaded communities—invasional meltdown hypothesis; and (3) different alien plant species richness in communities of different regions. In each region, 24 sample plots of 400 m2 were described: 12 invaded and 12 non-invaded by A. negundo. The species richness of invaded plots decreased: total richness decreased by 21%–43%; the richness of herbaceous plants decreased by 24%–43%; and woody richness decreased by 8%–44%. The proportion of alien herbs in plots invaded by A. negundo increased by 35%. This is the first, although not exhaustive, confirmation of the invasional meltdown hypothesis for communities invaded by A. negundo. Alien herbs increasingly invaded communities of the Belarusian Polesia, alien trees—communities of the Middle Urals. Thus, regional geographical and floristic conditions should be considered when assessing the invasion consequences. [ABSTRACT FROM AUTHOR]

Context: Native early-successional plants and invasive exotic plants often colonize the same disturbed space and have similar functions, making interactions likely. Knowing whether these interactions are facilitative or competitive across different scales will help determine the influence of such species across a forested landscape. Objective: We evaluated the impacts of an early-successional, nitrogen-fixing native (facilitator), Robinia pseudoacacia, and an allelopathic invasive (inhibitor), Ailanthus altissima, on regeneration, basal area, and diversity of forests at local and regional scales. Methods: Locally, all woody stems were mapped in three post-disturbance, mid-successional plots at two sites in Virginia, US. Plots contained A. altissima or R. pseudoacacia or both. Target species were evaluated regionally and spatially using USDA Forest Inventory and Analysis data across 31 eastern states, US. Results: Spatial contagion was found between A. altissima and R. pseudoacacia at both scales. Regeneration of A. altissima was much greater than that of R. pseudoacacia but native tree regeneration was negatively associated with both target species. Regionally, R. pseudoacacia was more common than A. altissima. At both scales, A. altissima was more likely to form dense stands than R. pseudoacacia. Locally, plot types did not differ in tree diversity. Regionally, R. pseudoacacia plots had higher tree diversity than plots without either target species. Conclusions: Robinia pseudoacacia and A. altissima's positive association is maintained into mid- and late-successional forests and A. altissima inhibits regeneration locally and regionally. Robinia pseudoacacia shows a positive effect on diversity but only when compared with mature forests at the regional scale. [ABSTRACT FROM AUTHOR]

Exotic plants usually exhibit problems for native species where they coexist. This study evaluated the effect of naturalized alien Cenchrus echinatus L. on native plants in urban vegetation. A field trial was conducted to assess the effect of this species on the cover and diversity of the native vegetation. The allelopathic potential of such species was examined. Sites comprising C. echinatus had a lower cover than some native species. Lower floristic diversity was observed at higher densities of this plant. The soil under this plant attained lower N, P, and K contents. This soil had no effect on the germination and growth of native species. It also comprised germinable seeds of some species which were absent from the standing vegetation. Exotic C. echinatus may exert negative effects on the native vegetation of the urban plant communities. A dense cover of this species may inhibit the germination of native species, leading to a reduction in their cover. Reduction in cover and diversity of native species may not be attributed to allelopathy. These results suggest that naturalized C. echinatus may be more competitive than the native ones, particularly at higher densities. Furthermore, it may represent a threat to the native plants in the urban vegetation. [ABSTRACT FROM AUTHOR]

This review explores the implications of climate change for the functioning of plant species as biogeomorphic engineers of temperate river systems, including the potential for an increasing role of invasive alien plant species (IAPS). First, we introduce engineer plants as important controls, along with flowing water and transported sediments, on the morphodynamics of river systems and the likelihood that climate change may affect the contributions of species within their native habitats. We then examine through the prism of the fluvial biogeomorphic succession model how climate change may accelerate the establishment of IAPS, the possible consequences for the performance and/or persistence of native engineer plant species, and thus the potential pathways of influence for IAPS on river morphodynamics. Finally, we present examples of the impacts of invasions by specific plant species along particular river systems and consider their potential biogeomorphic impact against a backdrop of climate change. Loss, replacement, or displacement of native plant species in the river corridor by IAPS can potentially alter biogeomorphic phenomena by directly increasing or decreasing erosion and/or sedimentation and the associated development of fluvial landforms. In the shorter term, increased climate disturbance may provide more establishment opportunities for opportunistic IAPS. In the longer term, under heavy establishment, IAPS may alter the coupled assembly of plant communities, fluvial landforms and ecosystem development, potentially resulting in river landscape metamorphosis and significantly changed habitat conditions. This article is categorized under:Science of Water > Water and Environmental ChangeWater and Life > Nature of Freshwater EcosystemsWater and Life > Stresses and Pressures on EcosystemsWater and Life > Conservation, Management, and Awareness [ABSTRACT FROM AUTHOR]

A great deal of effort has been made to clear invasive alien plants in South Africa, yet it remains unclear if the clearing efforts are yielding positive soil and vegetation recovery trajectories. A few short-term studies have been conducted to monitor soil and vegetation recovery after alien plant removal in South Africa, but convincing, long-term monitoring studies are scarce yet needed. We investigated topsoil and vegetation recovery following Eucalyptus grandis removal 14 years ago by Working for Water in Makhanda, Eastern Cape province of South Africa. The detailed topsoil and vegetation surveys were conducted on forty 10 m × 10 m plots that were in paired cleared and natural sites. The results show no significant differences for the measured soil pH, total N, total C, K, Ca, and Na between the cleared and natural sites, an indication that the two sites are becoming similar. Similarly, the gravimetric soil moisture content shows no significant differences between the two sites, although monthly variations are observed. The topsoils in the cleared sites are hydrophobic as compared to those in the natural sites, which are wettable. We observed no significant vegetation diversity differences between the two sites, with native woody species, such as Crassula pellucida and Helichrysum petiolare, frequently occurring in the cleared sites. We recorded low reinvasion by E. grandis and other secondary invaders like Acacia mearnsii and Rubus cuneifolius in the cleared sites. Based on these results, we conclude that 14 years after E. grandis clearing, both topsoil and vegetation recovery are following a positive trajectory towards the natural sites. However, both reinvasion and secondary invasion have the potential to slow down soil and native vegetation recovery. Recommendations such as timeous follow-up clearing and incorporating restoration monitoring in the WfW clearing programme are discussed. [ABSTRACT FROM AUTHOR]

Cities are often hotspots for biological invasions, showing much higher percentages of alien species than non-urbanized settings. The reasons are multiple and are mostly related to two main factors: their heterogeneous, highly disturbed habitats and their many gateways that allow alien species introduction (e.g., airports, roads, train stations, or gardens). In addition to being a sink of biological invasions, cities can also be a source of the spread of alien species into surrounding landscapes, which adds further complexity to this issue. Herein, we are presenting the results of a five-year survey of the alien flora of Montjuïc, the largest urban hill in Barcelona (Spain). In just about 3.4 km2, we recorded up to 247 alien plant taxa, a figure much higher than those of many other Mediterranean cities and which clearly points to the role of Montjuïc as a hotspot for alien plants. The comparison with the alien flora of its surrounding region (coastal Catalonia) suggests that the alien flora of Montjuïc would have become enriched through many immigration episodes from close geographic areas. The hill, however, would have also acted as a source of the spread of alien plants, and indeed, some species have not been detected yet beyond the confines of Montjuïc. This study aims to be a key tool to ensure early detection and also to develop appropriate management and/or eradication actions. [ABSTRACT FROM AUTHOR]

Both urban and rural environments around the globe have become dominated by alien plant species to the extent that plantscapes from one region or country have become difficult to distinguish from many others. This process of plant community homogenisation comes at a cost to cultural identity and undermines people's sense of place. Although invasive alien plant species have received considerable attention in recent decades, issues with non‐invasive alien plant species have largely been ignored, and yet they contribute significantly to biotic homogeneity and impose an ever accumulating invasion debt: a debt that increases in proportion with their population sizes. By contrast, an abundance of native species in the places where people live is important for strengthening commitment to biodiversity conservation. Is there therefore sufficient evidence of harm from increasing numbers of non‐invasive alien plants to justify local and central governments introducing measures to substantially reduce the proportion of non‐invasive aliens in both urban and rural environments? [ABSTRACT FROM AUTHOR]

Current control methods for invasive alien plants (IAPs) have acceptable short-term outcomes but have proven to be unfeasible or unaffordable in the long-term or for large invaded areas. For these reasons, there is an urgent need to develop sustainable approaches to control or restrict the spread of aggressive IAPs. The use of waste derived from IAP control actions could contribute to motivating the long-term management and preservation of local biodiversity while promoting some economic returns for stakeholders. However, this strategy may raise some concerns that should be carefully addressed before its implementation. In this article, we summarize the most common methods to control IAPs, explaining their viability and limitations. We also compile the potential applications of IAP residues and discuss the risks and opportunities associated with this strategy. [ABSTRACT FROM AUTHOR]

Simple Summary: This study was carried out to clarify the spatial distribution of exotic plants at national, regional, and local levels, as well as their ecological impacts, and to prepare a strategy to reduce the impacts in Republic of Korea. A review of the biological characteristics of invasive plants showed that therophytes, annual plants, plants that disperse seeds by gravity (D4), erect form (E), and nonclonal growth form (R5) occupied the highest proportion. Exotic plants usually preferred disturbed areas such as lowlands, roadsides, and bare ground. At the national level, the distribution of exotic plants tended to be dominated by topographic conditions and increased around urbanized areas, agricultural fields, and coastal areas. At the regional level, they appeared in artificial plantations, vegetation due to disturbance, and vegetation established on lower slopes compared with upper slopes. At the local level, exotic plants appeared abundantly in the introduced vegetation, whereas they were rare in the native vegetation. Restorative treatments recovered species composition close to the reference vegetation and species diversity reduced by invasive species. This study was carried out to clarify the spatial distribution of exotic plants at national, regional, and local levels, as well as their ecological impacts, and to prepare a strategy to reduce the impacts in Republic of Korea. This study was attempted at the national, regional, and local levels throughout Republic of Korea. Compositae occupied the highest percentage among invading exotic plants in Republic of Korea. A review of the biological attributes of exotic plants based on the dormancy form, longevity, disseminule form, growth form, and radicoid form showed that therophytes, annual plants, plants that disperse seeds by gravity (D4), erect form (E), and nonclonal growth form (R5) occupied the highest proportion. At the national level, the spatial distribution of exotic plants tended to depend on topographic conditions such as elevation and slope degree, and to increase around urbanized areas, agricultural fields, and coastal areas. The habitat types that exotic plants established were similar in their native habitat and in Korea, where they invaded. They preferred disturbed land such as roadsides, bare ground, agricultural fields, and so on. The spatial distribution of vegetation types dominated by exotic plants was restricted in the lowland. The proportion of the exotic/native plants tended to proportionate reversely to the vegetation type richness (the number of vegetation types); that is, the ecological diversity. The proportion of the exotic plants was higher in artificial plantations, vegetation due to disturbance, and vegetation established on lower slopes compared with upper slopes. Even at the local level, the exotic plants appeared abundantly in the introduced vegetation, while they were rare in the native ones. In the vegetation infected by exotic species, not only the species composition changed significantly, but the species diversity also decreased. Restorative treatment by introducing mantle vegetation around the hiking trail inhibited the establishment of exotic plants. Further, the restoration practice recovered the similarity of the species composition compared to the reference vegetation and increased the species diversity. [ABSTRACT FROM AUTHOR]

The invasion of exotic plants in the river–lake ecotone has seriously affected the nutrient cycling processes in wetland soil. The South American species Alternanthera philoxeroides (Mart.) Griseb. is rapidly invading the river–lake ecotone in subtropical China, and has become the dominant species in the river–lake ecotone. However, there have been few studies on the effects of A. philoxeroides invasion on soil phosphorus (P) cycling and bioavailability in this ecotone. Here, we measured the bioavailable P fractions, physicochemical properties and nutrient content in the surface soils of the native plant (Zizania latifolia (Griseb.) Turcz and Nelumbo nucifera Gaertn.) communities and the adjacent invasive A. philoxeroides communities in three river–lake ecotones with different nutrient substrates in the subtropical Dongting Lake basin over a 3‐year period to reveal the effects of A. philoxeroides invasion on the morphology and concentrations of soil bioavailable P. The principal coordinate analysis results showed that the A. philoxeroides invasion significantly altered the bioavailable P concentrations in the soil of native plant communities in the different river–lake ecotones, and this effect was not disturbed by the heterogeneity of the soil matrix. However, the effects of invasion into different native plant communities on the fractions of soil bioavailable P were different. Compared with native Z. latifolia and N. nucifera communities, A. philoxeroides invasion increased the concentration of inorganic P by 39.5% and 3.7%, respectively, and the concentration of organic P decreased by 32.7% and 31.9%, respectively. In addition, the invasion promoted P cycling and accumulation in the river–lake ecotone, which resulted in average decreases in the soil N:P and C:P ratios of 7.9% and 12.5%, respectively. These results highlight the impact of exotic plant invasions on nutrient cycling in wetland ecosystems in the river–lake ecotone, and this process may be detrimental to the late recovery of native plants. [ABSTRACT FROM AUTHOR]

In environmental restoration, evaluating the effect of control actions on alien species is essential for a correct assessment of the success of the restoration. A simple method for the evaluation of the dynamics of alien plants after manual and mechanical control in restored areas is proposed in this work. This method is based on the cover-abundance of alien plants, the size of the inventoried area and subsequently corrected with the degree of invasiveness based on national catalogues. Alien plants data abundances are obtained from floristic relevés retrieved from the restoration actions, carried out in the Eo River (Spain) during the LIFE Fluvial project (2018–2021). The Invasive Alien Plants Index (IAPI) was calculated, before and after the control actions for three ecological units (fluvio-estuarine, riverbank and lake). In all cases, index decreases after the control actions and it is sensitive to the changes that may occurs as recolonization by new alien species. As a whole, in the Eo River, a decrease of 53% of the IAPI has been obtained from 2018 to 2021, which estimate the effect of alien plants control. This indicator is applicable to any type of habitat, ecosystem or region and is adapted to different administrative areas that have published an official list of invasive species. [ABSTRACT FROM AUTHOR]

Invasive alien species represent one of the main environmental threats to native biodiversity and can also strongly alter the biogeochemical cycles within an ecosystem. This study aims to define the distribution of the invasive alien species Cotula coronopifolia L. within the protected wetland "Variconi" (Campania region, southern Italy) and evaluate the potential role of water geochemical features as interpretation tools for pattern distribution. The presence of C. coronopifolia was assessed in the field, and a distribution map was drawn; concomitantly thirty-nine water samples were collected from groundwater and surface water bodies for chemical analyses. The results showed that C. coronopifolia preferentially colonized the sector of the wetland characterized by high halinity, while it is totally absent in retrodunal and sandy coastal area with very high halinity. The cartography presented can be used as a tool to help target future management interventions. Through our multidisciplinary approach, new evidence has been provided on the ecology of this invasive alien plant that occupies several wetlands worldwide. The replicability of this method may be useful to assess the level of invasion of an alien species but also to predict its evolution as a function of environmental parameters. [ABSTRACT FROM AUTHOR]

The management of biological invasions, which pose a growing threat to natural resources and human well-being, is critical for reducing associated negative impacts. As part of the process of developing a strategy for the management of biological invasions in the South African National Biodiversity Institute's (SANBI) gardens, we collated a list of alien plant species from 13 gardens as part of a situational analysis. We requested lists of alien plant species recorded in each of the SANBI's gardens. A total of 380 records included 225 alien plant species belonging to 73 families. A significant number of species were intentionally introduced through horticultural trade as ornamentals (49%; n = 225), while 20.9% were consumed as either food or medicine by humans. Plant life forms included woody and herbaceous plants, graminoids, succulents and ferns. Herbaceous (42.7%; n = 225) and woody plants (3.8%) were the dominant life forms. The Walter Sisulu National Botanical Garden had the highest number of alien species (88 species), followed by Kirstenbosch (61 species) and Pretoria (46 species) National Botanical Gardens, with herbaceous species constituting the largest number in all gardens (i.e., 47, 19, and 27 species, respectively). The number of species that we recorded that were listed in the National Environmental Management: Biodiversity Act (NEM: BA) (Act No. 10 of 2004): Alien and Invasive Species Regulations' categories were not notably different from the number of unlisted species (58.2% vs. 42.8%). The number of species listed in the different categories varied significantly across the different gardens, with a significantly higher number of unlisted species and of Category 1b species in the Walter Sisulu, Kirstenbosch and Pretoria National Botanical Gardens than in other gardens. That a significantly larger number of alien species originated from South America points to the need to improve biosecurity controls on existing relations. The results of this study provided a baseline database to help comparison between successive surveys in future. [ABSTRACT FROM AUTHOR]

Interspecific competition determines the invasive capability of alien plants. Phytolacca americana, one of the most destructive invasive plants in China, was first discovered and recorded in China in 1935. Since its arrival, the rapid expansion of the species has driven out a native congener, Phytolacca acinosa. In this study, we assessed the competitive interaction of the invasive P. americana the native P. acinosa in a pot experiment at Yunnan University. Our results indicate that P. americana severely inhibits the growth and reproduction of P. acinosa. Furthermore, P. americana demonstrated a superior resistance against both insect predation and bacterial infection. We suggest that this improved tolerance against herbivory and potentional pathogen damage may be a cornerstone to the invasive success of Phytolacca americana. [ABSTRACT FROM AUTHOR]

It is generally accepted that urbanisation is changing the composition of species, mostly in urban and surrounding areas, through intentional introduction. The South African National Status Report of 2017 on biological invasions has shown that there is a dearth of knowledge about the invasion status of many invasive alien species in many parts of the country, such as the critically threatened vegetation, Woodbush Granite Grassland (WGG) in Limpopo Province. Consequently, the present study investigated the status of alien plants species in WGG. A roadside survey was carried out in Haenertsburg Village and its vicinity. Roads were used as survey units, and the dumpsite was used as a high risk area. A total of 136 species were identified, belonging to 46 botanical families. This study report the occurrence of 72 species which are regulated by the South Africa's National Environmental Management: Biodiversity Act (NEMBA, Act 10 of 2004). The present study found results significantly different from existing databases (X2 = 16.33473, p = .0001). Included in our list are alien species that need urgent eradication: Coreopsis lanceolata L., Cytisus scoparius (L.) Link, Iris pseudacorus L., Pueraria montana (Lour.) Merr, - and Rubus species as NEMBA category 1a species. Illegal dumping of agricultural waste was found to be one of the contributing factors to IAS in the area. Our study shows that Woodbush Granite Grassland is facing a new threat from invasive species. [ABSTRACT FROM AUTHOR]

Invasive exotic plant species (IEPs) are widely distributed across the globe, but whether IEPs are drivers or passengers of habitat change in the invaded spaces remains unclear. Here, we carried out a vegetation and soil survey in 2018 and two independent field experiments (Pedicularis kansuensis removal in 2014 and 2015, and fertilization experiment since 2012) and found that the invasive annual P. kansuensis was at a disadvantage in light competition compared with perennial native grasses, but the successful invasion of P. kansuensis was due to the sufficient light resources provided by the reduced coverage of the native species. Conversely, nitrogen enrichment can effectively inhibit P. kansuensis invasion by increasing the photocompetitive advantage of the native species. sP. kansuensis invasion did not reduce species richness, but did increase plant community coverage, productivity and soil nutrients. Furthermore, the removal of P. kansuensis had little effect on the plant community structure and soil properties. Our results suggest that the passenger model perfectly explains the benign invasive mechanism of P. kansuensis. The invasion "ticket" of P. kansuensis is a spare ecological niche for light resources released by overgrazing. [ABSTRACT FROM AUTHOR]

The southern side of the Daba Mountain area is a hotspot of global biodiversity and an essential barrier promoting ecological security. However, knowledge about the distribution status and transmission pathways of invasive alien species (IAS) in this area is limited. We counted the IAS on the southern side of the Daba Mountain area through sample transects and analyzed the factors affecting their spatial distribution. We also assessed IAS risk using the analytic hierarchy process (AHP), which found 64 IAS belonging to 23 families and 53 genera. Around rivers and roads, the results showed a vertical two-way dispersal pattern. Human and environmental factors, such as a very dense transportation network, can affect the distribution pattern of IAS. AHP assessed 43 IAS (67.19%), primarily distributed in villages and towns, as being of high or medium risk. High- and medium-risk IAS should be the focus of invasion prevention and control, and priority should be given to controlling the spread of IAS around rivers and roads. [ABSTRACT FROM AUTHOR]

Identifying the distribution dynamics of invasive alien species can help in the early detection of and rapid response to these invasive species in newly invaded sites. Ageratina adenophora, a worldwide invasive plant, has spread rapidly since its invasion in China in the 1940s, causing serious damage to the local socioeconomic and ecological environment. To better control the spread of this invasive plant, we used the MaxEnt model and ArcGIS based on field survey data and online databases to simulate and predict the spatial and temporal distribution patterns and risk areas for the spread of this species in China, and thus examined the key factors responsible for this weed's spread. The results showed that the risk areas for the invasion of A. adenophora in the current period were 18.394° N–33.653° N and 91.099° E–121.756° E, mainly in the tropical and subtropical regions of China, and densely distributed along rivers and well-developed roads. The high-risk areas are mainly located in the basins of the Lancang, Jinsha, Yalong, and Anning Rivers. With global climate change, the trend of continued invasion of A. adenophora is more evident, with further expansion of the dispersal zone towards the northeast and coastal areas in all climatic scenarios, and a slight contraction in the Yunnan–Guizhou plateau. Temperature, precipitation, altitude, and human activity are key factors in shaping the distribution pattern of A. adenophora. This weed prefers to grow in warm and precipitation-rich environments such as plains, hills, and mountains; in addition, increasing human activities provide more opportunities for its invasion, and well-developed water systems and roads can facilitate its spread. Measures should be taken to prevent its spread into these risk areas. [ABSTRACT FROM AUTHOR]

Carpobrotus acinaciformis and C. edulis are well-known invasive alien plants native to South Africa, whose detrimental effects on native communities are widely documented in the Mediterranean basin and thus largely managed in coastal ecosystems. Most of the literature on these species focuses on their impacts on habitats of sandy coastal dunes, while the effects of Carpobrotus spp. invasion on other habitats such as rocky cliffs and coastal scrubs and garrigues are almost neglected. We present a study case conducted on a small Mediterranean island where Carpobrotus spp. invaded three different natural habitats listed within the Habitat Directive 92/43/CEE (Natura 2000 codes 1240, 1430, and 5320). We surveyed the presence and abundance of native species and Carpobrotus spp. on 44 permanent square plots of 4 m2 in invaded and uninvaded areas in each of the three habitats. We found impacts on plant alpha diversity (intended as the species diversity within each sampled plot) in all the habitats investigated in terms of a decrease in species richness, Shannon index, and abundance. Invaded communities also showed a severe change in species composition with a strong homogenization of the floras of the three habitats. Finally, the negative effect of invasion emerged even through the analyses of beta diversity (expressing the species diversity among sampled plots of the same habitat type), with Carpobrotus spp. replacing a large set of native species. [ABSTRACT FROM AUTHOR]

Riparian zones are among the most threatened habitats due to invasive species. Traditionally, studies on invasive alien plants (IAPs) of riparian zones have focused on their ecological implications. Studies assessing the impacts of IAPs on ecosystem services (ES) and ecosystem disservices (EDS) through people's perceptions are lacking in this habitat. This study was conducted in the riparian zone of the Ganga River in Varanasi, India. We used a questionnaire‐based survey to assess people's perceptions of IAPs and their potential to provide ES and EDS. Results indicated that residents were aware of IAPs and perceived these both positively (providing ES) and negatively (providing EDS). Soil stabilization and loss of native plant diversity were the most commonly perceived ES and EDS respectively. Socio‐demographic variables such as age and education shape people's perceptions of IAPs. Younger and educated respondents were more likely to perceive IAPs negatively. Respondents most commonly used fire as a practice to manage IAPs. They placed Parthenium hysterophorus L. as the highest priority based on its impacts and management needs. This study highlights the need to incorporate public perceptions into the policy, planning, and management of IAPs, particularly in the riparian zone. [ABSTRACT FROM AUTHOR]

The introduction of alien plant species can lead to biological invasions, which have major impacts on people and the environment. Trachycarpus fortunei (Hook.) H. Wendl. (Arecaceae) is an alien plant (palm tree) that has been introduced as an ornamental into urban areas across the world, but in many regions, it has started invading forests and other natural environments leading to negative impacts. To improve understanding and guide management, this study sought to assess people's knowledge and perceptions of T. fortunei in Ticino, the region in Switzerland where invasions of the species are most common. To achieve this goal, an online survey was conducted, and a total of 487 responses were received. The formal name(s) (scientific or common names) of T. fortunei were unknown to almost all participants (89 %), and people mostly just called them "palm". Most respondents were familiar with the term invasive alien species (IAS) (88 %) and were aware of the invasiveness (spread) of T. fortunei (73 %). The study showed that although people like to see the palm in the region (51 %) and enjoyed the related sense of place it provides, respondents have become aware of the challenges associated with invasions and the majority (65 %) would like to see more done to control the spread of T. fortunei invasions within natural areas, particularly forests. To improve management, a large number of respondents (63 %) mentioned that education and awareness programmes should be implemented to provide people with knowledge on how to deal with invasive alien plants and thus prevent further spread. Almost a third of respondents supported (32 %) the regulated sale of T. fortunei in an effort to reduce invasions. Educational level, gender, and age affected response patterns, and this needs to be accounted for within strategic management planning, in particular, within education and awareness-raising initiatives. Tailored and targeted educational campaigns and management plans need to be established to prioritise and improve control of this invasive palm in Switzerland in the long term. [ABSTRACT FROM AUTHOR]

Plant invasions have been linked to displacement of native vegetation and altering of fire regimes and might influence vector mosquito populations by altering habitats or nutrient inputs. Whereas wildfire effects on terrestrial ecosystems are relatively well‐studied, ash depositions into aquatic ecosystems and effects on semi‐aquatic taxa such as mosquitoes have remained overlooked. Here, we investigated mosquito colonization in water treated with ash from native plants [quinine tree (Rauvolfia caffra), Transvaal milk plum (Englerophytum magalismontanum), apple leaf (Philenoptera violacea)] and invasive alien plants [i.e., lantana (Lantana camara), guava (Psidium guajava), red river gum (Eucalyptus camaldulensis)] in containers at two ash concentrations (i.e., 1, 2 g/L). Overall, there was no statistically clear difference in colonization between ash from native and alien species. We recorded colonization by two mosquito genera (Culex spp. and Anopheles spp.), with Culex generally much more abundant than Anopheles. Few differences were identified among the plants, with statistically clear effects of ash type and concentration on larval and pupal stages. High Culex egg and larval abundances were shown in lantana and apple leaf treatments compared to controls, and milkplum versus controls for pupae of both genera. Further research is required to elucidate the influence of nutrient inputs from different ash species on vector mosquito population dynamics. [ABSTRACT FROM AUTHOR]

The impact of climate change on the germination and growth of invasive alien plants varies depending on the plant species and invasion process. We experimentally assessed the responses of the invasive alien plant Acacia mearnsii to future climate change scenarios—namely, elevated temperature as well as high and low rainfall. Acacia mearnsii was grown at an elevated air temperature (+2 °C), high rainfall (6 mm per day), and low rainfall (1.5 mm per day), and its germination and growth performance were measured over five months. We further examined changes in soil nutrients to assess if the above-mentioned climate change scenarios affected soils. Both elevated temperature and high rainfall did not influence A. mearnsii germination and seedling growth. In contrast, we observed reductions in A. mearnsii germination and growth in the low rainfall treatment, an indication that future drought conditions might negatively affect A. mearnsii invasion. We noted that elevated temperature and rainfall resulted in varied effects on soil properties (particularly soil C, N, Ca, and Mg content). We conclude that both elevated temperature and high rainfall may not enhance A. mearnsii invasion through altering germination and growth, but a decrease in A. mearnsii invasiveness is possible under low rainfall conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding biological invasion mechanisms is crucial to design effective management strategies preventing their impacts on ecosystems. If the role of long-distance dispersal and age-dependent fecundity in plant invasion speed has been characterized in theory, empirical support is still rare given the difficulty to jointly fit demographic and spread parameters of dynamic models to available data. We proposed a statistical model to fit such parameters to heterogeneous observations collected across space and time. We can directly test hypotheses on the importance of various mechanisms in a past invasion. We demonstrated the potential of this method by determining the roles of human-mediated long-distance dispersal and age-dependent fecundity in the invasion of the shrub Plectranthus barbatus in South Africa. Our model revealed a massive wave of spread driven by human-mediated long-distance dispersal and originating from the cities of first introduction. The species completed its invasion of all favorable areas a few years after, in the mid-1990s. Without human-mediated long-distance dispersal, the maximum population would have been obly 30% of the current population. The delayed reproductive maturity explained the invasion lag phase. It highlights the importance of early eradication of weedy horticultural alien plants around urban areas to hamper the invasive spread. Plant invasions generate massive ecological and economic costs worldwide. Predicting their spatial dynamics is crucial to the design of effective management strategies and the prevention of invasions. Earlier studies highlighted the crucial role of long-distance dispersal in explaining the speed of many invasions. In addition, invasion speed depends highly on the duration of its lag phase, which may depend on the scaling of fecundity with age, especially for woody plants, even though empirical proof is still rare. Bayesian dynamic species distribution models enable the fitting of process-based models to partial and heterogeneous observations using a state-space modeling approach, thus offering a tool to test such hypotheses on past invasions over large spatial scales. We use such a model to explore the roles of long-distance dispersal and age-structured fecundity in the transient invasion dynamics of Plectranthus barbatus, a woody plant invader in South Africa. Our lattice-based model accounts for both short and human-mediated long-distance dispersal, as well as age-structured fecundity. We fitted our model on opportunistic occurrences, accounting for the spatio-temporal variations of the sampling effort and the variable detection rates across datasets. The Bayesian framework enables us to integrate a priori knowledge on demographic parameters and control identifiability issues. The model revealed a massive wave of spatial spread driven by human-mediated long-distance dispersal during the first decade and a subsequent drastic population growth, leading to a global equilibrium in the mid-1990s. Without long-distance dispersal, the maximum population would have been equivalent to 30% of the current equilibrium population. We further identified the reproductive maturity at three years old, which contributed to the lag phase before the final wave of population growth. Our results highlighted the importance of the early eradication of weedy horticultural alien plants around urban areas to hamper and delay the invasive spread. [ABSTRACT FROM AUTHOR]

Riparian zones provide many ecosystem services and are a frequently found type of green area in urban ecosystems; these areas increase the aesthetic value of urban landscapes. The aim of this 17-year study was to assess the applicability of passive vegetation restoration of the gravel/sand bars that emerged after a devastating flood along the river in the city of Prague. The number of species and the sum of their coverages rapidly increased for the initial six years. After the twelfth year, the vegetation composition gradually began to stabilize. Species diversity increased for seven years after the beginning of the succession and then remained essentially unchanged. The diversity values were lower on finer substrates with higher proportions of dust and clay particles. The neophytes, i.e. species introduced after the year 1500, established with more successful on substrates with greater soil skeleton proportions. Finer substrates were preferred by graminoids; among them, the invasive Arrhenatherum elatius was the most abundant. The share of invasive species in the total vegetation cover initially fluctuated at approximately 40%; after eight years, it stabilized at approximately 10%. The proportion of naturalized alien species stabilized within the range of 20–30%. The results show that a new type of species-rich vegetation spontaneously emerged on gravel/sand bars. The vegetation consisted mainly of native and naturalized non-invasive alien species. However, attention needs to be given to potential alien plant invasions. [ABSTRACT FROM AUTHOR]

Invasive alien species are responsible for several negative impacts worldwide. Managing biological invasions is often difficult and the success rate is quite low, but with good planning it is possible to achieve good results. Besides employing the correct methods and techniques, an overall strategy based on landscape dynamics and expected spatial patterns can be fundamental to achieve success. The decision of where to act can be embedded in a general strategy based on several criteria/goals such as control of large populations, connectivity disruption, and so on. This work focused on Acacia dealbata in a Natura 2000 site in Portugal, how the current amount and distribution can affect the spread pattern, and different possible strategies to approach the management. Based on the species dispersal traits, we argue that not only the area but also the perimeter (therefore, the shape) and location of the patches should be considered when fighting the invasion. Three scenarios were designed and compared using the perimeter–area ratio, a landscape dynamics analysis, and a connectivity index. Results show that removing the patches with higher perimeter–area ratio (mostly small satellite patches) would be more impactful than removing the larger patch or removing random intermediary perimeter–area patches first. After this approach based on landscape dynamics, the employment of a connectivity assessment provided an ordered list of patches to remove sequentially. Overall, this approach can be valuable in the early steps of the planning process, supporting better decisions regarding the available resources and contributing to maximize the effectiveness of the action. [ABSTRACT FROM AUTHOR]

Fungal invasions only recently started to receive more attention in invasion biology. This is largely attributed to little or non‐existent information about these inconspicuous organisms. Most invasion hypotheses focus on factors that increase invasion success; few try to explain why invasions fail. Here we hypothesize that a host–pathogen relationships can limit the invasiveness of an alien plant species in a novel range. To test this, we investigate whether the invasiveness of the Australian genus of Proteaceae, Banksia, in South Africa is determined by the alien and major invasive phytopathogen, Phytophthora cinnamomi. The presence of P. cinnamomi in Banksia root and soil was evaluated using morphological and molecular techniques. Isolates were cultured onto selective media and polymerize chain reactions and internal transcribing spacers were used for identification. Acetone leaf extracts of 11 Banksia spp. were screened for antimicrobial activity against P. cinnamomi, using the minimum inhibitory concentration assay. A total of 3840 Banksia individuals from seven localities were surveyed. Phytophthora cinnamomi was consistently isolated from Banksia species root and soil samples. Out of the 12 Banksia species that were screened for antimicrobial activity, four introduced species, B. burdettii, B. coccinea, Banksia hookeriana, and B. prionotes and the invasive B. integrifolia and B. ericifolia exhibited relatively high antimicrobial activity against P. cinnamomi (strain 696/12). We show that the phytopathogen in the native range has similar impact in the novel range and in doing so may limit invasion success of Banksia species with low antimicrobial activity. [ABSTRACT FROM AUTHOR]

As it is known, protected areas networks should (once again) protect the native ecosystems from the negative influence of alien species introduction. In this study, we select a protected area (Mordovia State Nature Reserve, IUCN category: I) in European Russia (Republic of Mordovia). Moreover, alien floras have never been compared between the Mordovian regional districts (managed areas) and protected areas. We aimed to compare the alien species proportion between the flora of the Mordovia State Nature Reserve and 23 floras of the regional districts. For this purpose, we used actual floristic checklists of both Mordovia State Nature Reserve (at present, more than 800 species) and the whole Mordovia (at present, more than 1470 species), as well as the set of the published additions to the flora of the region and Protected Area. The temporal comparison was performed between data of 2010 and 2022 years. We hypothesized that, contrary to the widely known fact on the intactness of Protected Areas, the Mordovia State Nature Reserve is characterized by a high proportion of alien plant species. The obtained results demonstrated that in the Mordovia State Nature Reserve, the alien species proportion before starting intense botanical studies was lower (10.7%) than in floras of certain managed areas (17.7% in the Kochkurovo district, 18.8% in the Insar district, or 22.0% in the Ardatov district). At the same time, additional studies resulted in a considerable increase in the alien species proportion in the flora of the protected area (19.0%) in comparison with data of the 2010 year. This indicates both the initial underestimation of the protected area's flora and the importance of additional purposeful investigations in obtaining the complete data on the flora composition. The obtained results in comparison with updated data for the Mordovian districts' floras are discussed in light of the current knowledge on the flora of the Mordovia State Nature Reserve and the Republic of Mordovia as a whole. [ABSTRACT FROM AUTHOR]

In 2019 we re-surveyed a site on the Agulhas Plain, South Africa, which had been part of a restoration project conducted in 2008. The site was invaded by invasive trees, mainly Australian Acacia species. In the original restoration program, the site had been burned and various treatments (i.e. sowing of competitive, fast-growing native species) were conducted to determine the effectiveness of different restoration strategies. The sowing of native species to assist the recovery process is defined as an active restoration method, whereas passive restoration only removes stressors for the ecosystem (e.g. removal of the invader) and leaves it to recover by itself. For this study, we conducted a vegetation survey at the previously restored sites and compared them with a nearby reference site where no intervention had taken place and which is characterised by near-pristine native fynbos vegetation. Secondly, we compared the new data from 2019 with older data from 2010. However, a decade after the initial restoration effort, both active and passively treated plots had not achieved the same condition (species richness, diversity, evenness) as the reference site. The results also show that active restoration is most likely unnecessary in fynbos restoration projects where there are nearby patches with native vegetation or the existing native seed bank is of sufficient size. It seems that it is more important to prevent the reinvasion of invasive alien plants so that the vegetation can recover over time without further disruption. [ABSTRACT FROM AUTHOR]

Invasive alien plant species have been identified as a major threat to biodiversity and the relationship with native avian dispersers may increase their invasion potential. The impact of invasive plant species needs to be quantified using comparable assessment tools across different habitats and species to allocate limited resources to high-priority species. Here, we used the Generic Impact Scoring System (GISS) to assess the impacts of 16 fleshy-fruited alien invasive plant species in South Africa generally dispersed by native avian species. The results showed that fleshy-fruited invasive species have both environmental and socioeconomic impacts. The cumulated impact scores for lantana (Lantana camara) and the tree of heaven (Ailanthus altissima) were the highest, with scores of 42 and 32, respectively. Some species, such as white mulberry (Morus alba), camphor tree (Cinnamomum camphora), American bramble (Rubus cuneifolius) and Brazilian pepper tree (Schinus terebinthifolius), had low overall impact scores of 8, 18, 14 and 16, respectively, but scored the maximum impact of 5 for certain mechanisms. Environmental impacts of fleshy-fruited invasive plant species had a high impact magnitude through effects on the ecosystem and vegetation. Socio-economic impacts were mainly through effects on forest production, agriculture and human health. Species with large crop sizes, small seeds and fruit sizes had higher environmental and socio-economic impact magnitude. The information generated in this study is important for guiding resource allocation and preventing the uncontrolled introduction of invasive species in South Africa. The impact of the fleshy-fruited invasive species transcended sectors and, therefore, effective management of invasive species will require the collaboration of multiple and inter-sectoral stakeholders in South Africa. [ABSTRACT FROM AUTHOR]