An unprotected vulnerable relict subtropical conifer-Keteleeria evelyniana: Its forests, populations, growth and endangerment by invasive alien plant species in China

Relict subtropical coniferous forests in China face severe fragmentation,resulting in declining populations,and some are under significant threat from invasive alien species.Despite the crucial importance of understanding forest dynamics,knowledge gaps persist,particularly regarding the impact of invasive plants on vulnerable natives like Keteleeria evelyniana.In this study,we investigated the impact of invasive plants on the regeneration of forests dominated by K.evelyniana,a subtropical relict species in southwestern China.For this purpose,we characterized forest dynamics of 160 forest plots featuring K.evelyniana as the primary dominant species and determined whether the presence of invasive plants was correlated with regeneration of K.evelyniana.We identified four distinct forest types in which K.evelyniana was dominant.We found that radial growth of K.evelyniana trees is faster in younger ageclasses today than it was for older trees at the same age.The population structure of K.evelyniana in each forest type exhibited a multimodal age-class distribution.However,three forest types lacked established saplings younger than 10 years old,a situation attributed to the dense coverage of the invasive alien Ageratina adenophora.This invasive species resulted in a reduction of understory species diversity.Additionally,our analysis uncovered a significant negative correlation in phylogenetic relatedness(net relatedness index)between native and invasive alien plant species in eastern Yunnan.This suggests closely related invasive species face heightened competition,hindering successful invasion.Taken together,our findings indicate that successful establishment and habitat restoration of K.evelyniana seedling/saplings require effective measures to control invasive plants.

Bio-Morphological Characters of Alien Legume Species, Influencing Their Invasion in Natural Plant Communities

Five alien legume species, actively invading in natural plant communities in European part of Russia, were studied—Lupinus polyphyllus Lindl., Galega orientalis Lam., Robinia pseudoacacia L., Amorpha fruticosa L. and Caragana arborescens L. Distribution ranges (considering their invasive status) were mapped. Not a single bio-morphological character to forecast invasion success in natural plant communities within secondary distribution range was found. The data of key value/importance for explaining invasive success of the species studied were obtained. Two hypotheses— Propagule Pressure and Evolution of Invasiveness—were critically analyzed in view of the received data.

InvasionDB: A genome and gene database of invasive alien species

Invasive alien species(IAS) are species whose introduction to areas outside of their native range cause harm to economics, biodiversity, and the environment. Understanding the genetic basis of invasiveness is critical for preventing invasion by an alien species and managing IAS with eco-friendly control methods. In addition, uncovering the genomic features of IAS is essential for accurately predicting invasiveness. However, even though increasing efforts have been devoted to sequencing the genomes of IAS, there is still not an integrated genome database for the invasive biology community. Here, we first determined a list of invasive plants and animals by mining references and databases. Then, we retrieved the genomic and gene data of these IAS, and constructed a database, Invasion DB. Invasion DB encompasses 131 IAS genomes, 76 annotated IAS assemblies, and links these data to conventional functions such as searching for gene coding sequences and Pfam, KEGG, NR annotations, BLAST server, JBrowse, and downloads services. Next, we analyzed 19 invasivenessrelated gene families which confer invasiveness in insects. To study the roles of noncoding RNA in invasiveness, we also annotated 135 494 mi RNAs, 89 294 r RNAs, and 2 671 941 t RNAs from these IAS. In summary, Invasion DB is useful for studying the invasiveness at the genomic level, and thus helps to develop novel management strategies to control IAS.

Diversity, Invasion Status and Usages of Alien Plant Species in Northeastern Hilly State of Tripura: A Confluence of Indo-Barman Hotspot

The present study has explored the first authentic catalogue of the alien flora of the foot Himalayan hilly region along with their diversity, uses, various ecological aspects and invasion status. Environmentally similar south and tropical American aliens are higher in numbers in this region. A total of 216 plant species under 158 genera belonging to 58 families have been compiled in this catalogue. This alien flora occupies ~14.5% of the state flora, while 3.47% is invasive. Families having a large number of alien species are Asteraceae followed by Caesalpiniaceae and Solanaceae. Most of the alien species (61.57%) are of American origin followed by Asia (15.28%) and African continent (12.04%). Life form analysis shows that herbs (42.6%) are dominated alien. Among all the aliens, 67 species are used as ornamental plant, followed by 50 medicinally useful plants. In the state neutralized aliens are (36.57%) followed by invasive alien (24.07%). The present study also reports five alien species for the first time from the study site. This base line study would be the foundation for further advance studies on the invasion ecology and for the future assessment and management of invasive species in this biodiversity rich zone. Present work obviously helps in the agricultural sector of the state as well as the country and gives a clue for further introduction of new species in the country.

A Study on Alien Invasive Plants from the Interactive Mechanism between Species Niche and Material/Energy Flow

[Objective]This study was to reveal the essence of mechanism about how the alien invasive plants spread.[Method]Species niche and material/energy flow were used as basic research indicators to analyze the intrinsic mechanism of alien plants invasion.[Result]Most of the invasive plants have not been explicitly defined and their effective control methods not brought forward.[Conclusion]Overrun of alien invasive plants depends on whether the niche of a species could be continuously met at spatial level.Based on this we put forward corresponding control measures,proposed an assumption to establish a cylinder-network model and discussed the definition of alien invasive plants.

Detecting the distribution of and public attitudes to charismatic alien species based on media coverage

Charismatic species are often reported by the media,providing information for detecting population status and public perception.To identify the number and distribution of free-living Black Swan(Cygnus atratus),a charismatic alien species in Chinese mainland and to detect the public and the media attitudes to the species,we analyzed the reports and emotional tendency from media coverage in 2000-2022 using manual reading,crawler extraction and latent Dirichlet allocation.A total of 6654 Black Swans were reported at 711 sites,including 147 individuals at 30 nature reserves.Successful breeding was reported at one-fourth of the total sites,including five nature reserves.The proportion of positive emotional tendency to Black Swans was overwhelming in the reports and was higher than that to alien species in general,suggesting that the public and the media are unaware of the risk of biological invasion.Effective management of invasive species requires the media clarifies the invasion risk of charismatic alien species.Promoting the unity between the harmfulness of abstract concept of alien species and the charisma of a specific alien species among the public help effective management.

Study on the Allelopathic Effects of Alien Invasive Species Cenchrus echinatus on Seed Germination and Seedling Growth of Solanaceae Crops

[Objective] This study aimed to investigate the potential ecological dam- ages of alien invasive species Cenchrus echinatus. [Method] By using seed germi- nation method, the effects of different concentrations of C. echinatus aqueous extracts on seed germination and seedling growth of three Solanaceae crops were investigated. [Result] After incubated for 5 d, no significant differences were observed in germination speed indices of Lycopersicum esculentum seeds between aqueous extract groups and control groups; germination speed indices of Solarium melongena seeds were significantly reduced with the increasing concentration of Cenchrus echinatus aqueous extracts; however, Capsicum frutescens seeds in various groups were not germinated. After incubated for 7 d, root lengths of Lycopersicum esculentum seedlings were inhibited with the increasing concentration of Cenchrus echinatus aqueous extracts, while stem lengths and comprehensive allelopathic effects were promoted; germination rates of Solanum melongena seeds in various groups were all significantly lower than control groups; root length, stem length and comprehen- sive allelopathic effects in higher concentration groups were inhibited; germination rates of Capsicum frutescens seeds were significantly inhibited, and those in the highest concentration group were not generated. After incubated for 14 d, all indica- tors of Solanum melongena were significantly inhibited; various indicators of Capsicum frutescens in the highest concentration group were significantly inhibited. [Conclusion] The sensitivity of three Solanaceae crops to Cenchrus echinatus aqueous extracts presented an overall order of Solanum melongena 〉 Capsicum frutescens 〉 Lycopersicum esculentum, suggesting that Cenchrus echinatus can to some extent inhibit the growth of several crops, which should be strictly prevented and controlled in agricultural production.

Alien invasive species in Siberia:current status and problem

Although alien and invasive plant species have been researched extensively in the European part of Russia,the situation in Siberia is another matter.Hitherto,alien and invasive species in Siberia have not received much attention because this problem was not especially acute in Siberia.The lack of attention on alien and invasive species in Siberia is attributed to three major reasons：1） Low vegetative productivity and sparse human populations in the Siberian territory have limited botanical research interest in the area.2） Severe Siberian climate likely prevents many alien and invasive species from increasing their distribution into Siberia.3） Most Siberian plant communities have not been human-transformed and thus may be resistant to newcomers.Nevertheless,recent increased economic activities have resulted in increasing plant migration to Siberia,and this process should be monitored.Furthermore,global environmental changes may also have made Siberia more favorable for more alien and invasive species.Currently,research on alien and invasive species has begun in the Altai-Sayan region（Western Siberia） and the Magadan region （Northeastern Asia）.

Marine Species Introduced on the French Channel-Atlantic Coasts: A Review of Main Biological Invasions and Impacts

The impacts of anthropogenisation modify permanently the distribution patterns of brackish and marine species. Globalization leads to a rapid increase of the numbers of introduced species anywhere in the world. Biological invasions often result in significant losses in the economic value, biological diversity and function of invaded ecosystems. This review presents the main pathways of introduction of non-indigenous species and the main benthic taxonomic groups being established and/or invasive along the French Channel-Atlantic coasts. A focus is put on main invasive marine species in the intertidal and subtidal zones of Brittany (France), among macroalgae (Sargassum muticum, Grateloupia turuturu, Undaria pinnatifida, Codium fragile and Gracilaria vermiculophylla), halophytes (Spartina alterniflora) and benthic invertebrates (Mollusks: Crepidula fornicata, Crassostrea gigas and Venerupis philippinarum). The species biology, introduction vectors, reproductive and dispersal capacities are considered, together with proliferation patterns along the Channel-Atlantic coasts. The ecological impacts of these species on the environment are also described, as well as the European regulations existing to limit alien species introduction and some examples of struggle against the invaders including eradication trials and biomass valorization. Last, the on-going impacts of global changes on alien species invasiveness along the Channel-Atlantic coasts are discussed.

Species and Distribution Characteristics of Alien Invasive Plants in Garden Greenbelt of Shijiazhuang City

[Objectives]The paper was to investigate the garden greenbelt in 30 sample plots such as parks,roads,communities,etc.in Shijiazhuang City.[Methods]The species,abundance and frequency of weeds in the greenbelt of public gardens were recorded through point-line-surface investigation,and typical plants were sampled.[Results]There were 56 species of alien invasive plants in garden greenbelts of Shijiazhuang City,belonging to 44 genera and 20 families.In terms of life form,herbaceous plants were absolutely dominant,accounting for 92.8%of the total.The most alien invasive plants were native to America,accounting for 66.1%of the total.In terms of introduction path,the plants introduced artificially and unintentionally accounted for almost half.The species and quantity of alien invasive plants were related to the size of greenbelt area,the length of the build time of the surveyed plot,the composition structure of greenbelt and the level of green management and protection.There was larger distribution of alien invasive plants in the sample plots with large greenbelt area,long build time,herbaceous-dominated greenbelt and low level of green management and protection.Among the 56 alien invasive plants,3 plants were toxic.From the perspective of invasiveness,the alien invasive plants in the garden greenbelt of Shijiazhuang City could be divided into 5 levels:invasive alien species of malignant consequences,invasive alien species of severe consequences,invasive alien species of partial consequences,invasive alien species of average consequences,and invasive alien species to be observed.[Conclusions]This study will provide a reference for the prevention and control of alien plant invasion,and lay a foundation for the prevention and control of existing invasive plants.

Uses of Invasive Alien Plant Species in Rema-Kalenga Wildlife Sanctuary of Bangladesh

An exploratory survey was conducted on the uses and role of invasive alien species(IAS) to local livelihoods in the Rema-Kalenga Wildlife Sanctuary in the northeastern hilly region of Bangladesh.Vegetation was sampled in 50 quadrates,each 10 m×10 m,and 25 line transects,each 50 m×20 m,through a combination of random and systematic sampling.Group discussions were also arranged with fifty local inhabitants(17 % of the total inhabitants) to learn the various uses of IAS.A total of 17 alien plant species belonging to 10 different families,of which Leguminosae constitutes the highest number(5 species),include tree(53%) followed by herb(12%),shrub(12%) and others(weed,climber and palm).The majority of the identified species were found to be used for fuel,followed by timber production,medicinal or curative uses,fodder,and many others.In addition to providing various forest products,alien tree species planted in forest plantation help provide many vital ecosystem services such as soil amelioration through nitrogen fixation.It is true that the alien species have some negative impacts on local ecosystems,and not all of them are harmful.Therefore,a national programme must be initiated to distinguish the harmful from the harmless species and to identify the uses and impacts of the former and latter.

Environmental Impacts of Invasive Alien Plant Species on the Biodiversity of the Nyika National Park, Rumphi District, Malawi

Invasive alien plant species have threatened the integrity of ecosystems and threatened biological integrity throughout the world. In the Nyika National Park, a number of alien invasive plant species have been reported. These invasive alien plants are reported to be very difficult that have caused adverse ecological, economic and social impact. The main objective of this study is to assess the environmental impact of plant invasive alien species in Nyika National Park in order to ascertain means of addressing the possible effects on the biodiversity. This study adopted an exploratory stance in order to answer the hypotheses where purposive and simple random sampling was used. Purposive sampling was only used to the staff of Nyika while simple random sampling was used to collect data from households surrounding Nyika National Park. The results revealed that invasive alien plant species have some ecological impacts of on the biodiversity of the Nyika National Park like change in physical habitats such as loss of native habitats, alteration of ground water regime, drying of rivers, loss of native species and alteration of biomass. The study would therefore be important to policy makers in guiding and development of policies and guidelines governing eradication of invasive alien plant species. The Department of National Parks and Wildlife (DNPW) can form partnership with various stakeholders with a clearly stated intention of developing a relationship, based on collaboration to enhance the control of invading alien plant species and the best management practices.

Impact of <i>Parthenium hysterophorus</i>L. Invasion on Species Diversity of Cultivated Fields of Bilaspur (C.G.) India

In present study invasion of Parthenium hysterophorus L. and its impacts on agriculture fields will be done in different cultivated crops in Bilaspur. The present work deals with diversity and distribution of weeds species in cultivated fields of Bilaspur C.G. A total number of 28 species under 27 genera and 16 families was distributed in three study sites (Koni, Sakri & Kota) of cultivated fields in Bilaspur C.G. These study sites were located in different altitudinal zones responding different conditions in the this study. The number of species per sites ranged from 13 to 24. In the Sakri, number of species was ranged from 17 to 27, and the relative density of plant species ranged between 0.77 (Heteropogon contortus, Solanum surratense, Vernonia cinneria and Leucas aspera) and 22.92 (Parthenium hysterophorus). In the Kota, number of species was ranged from 14 to 28, and the relative density of plant species ranged between 0.85 (Ageratum conyzoides, Heteropogon contortus, Triticum aestivum) and 29.06 (Zea mays) and 30.91 (Parthenium hysterophorus). In the Agriculture field, number of species was ranged from 15 to 28, and the relative density of plant species ranged between 0.58 (Leucas aspera) and 26.23 (Triticum aestivum). Present work will give the information that weeds are harmful to herbs, crops and medicinal plants. Parthenium weed can suppress and crowd out other weed species, and could form a single dominant population in the invasion area, causing serious threat to plant community biological diversity.

Use of GIS to Determine Potential Sources of Aquatic Invasive Species Invasions into Western South Dakota Reservoirs

The spread of Aquatic Invasive Species (AIS) is a constant threat for western US waters. The state of South Dakota detected zebra mussels (Dreissena polymorpha) for the first time at Lewis and Clark Reservoir in 2014. Since then, efforts have been towards preventing their further expansion. To determine possible avenues of infestation westward, we used ArcGIS to map the home zip codes of boaters using four western reservoirs (Belle Fourche Reservoir, Pactola Reservoir, Sheridan Lake and Angostura Reservoir). A 60-mile buffer was used to determine spatial relationships of boater zip codes to establish zebra mussel populations and was considered areas of high risk. We found that there were three instances where a boater came from a high-risk area during the study period. Our results show possible pathways for Dreissena expansion into western South Dakota reservoirs. Most notably is that exposure can occur from either an inter- or intra-state vector. This information confirmed that there is a risk of additional water bodies in South Dakota becoming infected. Based on past studies, prevention is the best method in slowing the expansion of zebra mussels in South Dakota. We suggest three actions, strategically placed decontamination stations, continued public awareness efforts and differentiating boat registration tags on watercraft that are near infested water bodies.

Review on studies of Eupatorium adenophorum--an important invasive species in China

Eupatorium adenophorum Spreng. was introduced in Yunnan Province of China around 1940. Since then it has been spreading rapidly, particularly in the southern and southwestern parts of China and caused serious economic loss. The biological research and inte-grated control on E. adenophorum were carried out from 1980's in Yunnan Province. Together with other 15 invasive external species, the weed has been listed in the White Paper by The State Environmental Protection Administration of China. This paper briefly reviews the studies on natural distribution, biological character, ecological character, chemical component, hazard, potential application and the control of E. adenophorum. The research direction for this invasive external species in future was also discussed.

Predicting potential invasion risks of Leucaena leucocephala(Lam.)de Wit in the arid area of Saudi Arabia

The presence of invasive plant species poses a substantial ecological impact,thus comprehensive evaluation of their potential range and risk under the influence of climate change is necessary.This study uses maximum entropy(MaxEnt)modeling to forecast the likelihood of Leucaena leucocephala(Lam.)de Wit invasion in Saudi Arabia under present and future climate change scenarios.Utilizing the MaxEnt modeling,we integrated climatic and soil data to predict habitat suitability for the invasive species.We conducted a detailed analysis of the distribution patterns of the species,using climate variables and ecological factors.We focused on the important influence of temperature seasonality,temperature annual range,and precipitation seasonality.The distribution modeling used robust measures of area under the curve(AUC)and receiver-operator characteristic(ROC)curves,to map the invasion extent,which has a high level of accuracy in identifying appropriate habitats.The complex interaction that influenced the invasion of L.leucocephala was highlighted by the environmental parameters using Jackknife test.Presently,the actual geographic area where L.leucocephala was found in Saudi Arabia was considerably smaller than the theoretical maximum range,suggesting that it had the capacity to expand further.The MaxEnt model exhibited excellent prediction accuracy and produced reliable results based on the data from the ROC curve.Precipitation and temperature were the primary factors influencing the potential distribution of L.leucocephala.Currently,an estimated area of 216,342 km^(2)in Saudi Arabia was at a high probability of invasion by L.leucocephala.We investigated the potential for increased invasion hazards in the future due to climate change scenarios(Shared Socioeconomic Pathways(SSPs)245 and 585).The analysis of key climatic variables,including temperature seasonality and annual range,along with soil properties such as clay composition and nitrogen content,unveiled their substantial influence on the distribution dynamic of L.leucocephala.Our findings indicated a significant expansion of high risk zones.High-risk zones for L.leucocephala invasion in the current climate conditions had notable expansions projected under future climate scenarios,particularly evident in southern Makkah,Al Bahah,Madina,and Asir areas.The results,backed by thorough spatial studies,emphasize the need to reduce the possible ecological impacts of climate change on the spread of L.leucocephala.Moreover,the study provides valuable strategic insights for the management of invasion,highlighting the intricate relationship between climate change,habitat appropriateness,and the risks associated with invasive species.Proactive techniques are suggested to avoid and manage the spread of L.leucocephala,considering its high potential for future spread.This study enhances the overall comprehension of the dynamics of invasive species by combining modeling techniques with ecological knowledge.It also provides valuable information for decision-making to implement efficient conservation and management strategies in response to changing environmental conditions.

A risk assessment system for alien plant bio-invasion in Xiamen,China

Bio-invasion has caused serious ecosystem damage and enormous economic losses in China,and it has been the greatest factor to island bio-diversity reduction.Xiamen,as an important seaport with a relatively high conservation value,is particularly vulnerable to bio-invasion for its typical island ecosystem as well as frequent human-made disturbance.As a result of field surveys,literature review, and consultation with experts,a list of 67 alien plants identified as major invaders(12 species)and emerging invade...

Effect of an Alien Species Spartina alterniflora Loisel on Biogeochemical Processes of Intertidal Ecosystem in the Jiangsu Coastal Region,China

Spartina alterniflora Loisel, a species vegetating in intertidal flats along the eastern coast of the United States, was introduced in China almost 30 years ago and has become an urgent topic due to its invasiveness in the coastal zone of China. The impacts of this alien species S. alterniflora on intertidal ecosystem processes in the Jiangsu coastland were investigated by comparing the sediment nutrient availability and trace element concentration characteristics in a mud flat and those of a four-year old Spartina salt marsh that had earlier been a mudflat. At each study site, fifteen plots were sampled in different seasons to determine the sediment characteristics along the tidal flats. The results suggested that Spartina salt marsh sediments had significantly higher total N, available P, and water content, but lower pH and bulk density than mudflat sediments. Sediment salinity, water content, total N, organic C, and available P decreased along a seaward gradient in the Spartina salt marsh and increased with vegetation biomass. Furthermore, the concentrations of trace elements and some metal elements in the sediment were higher under Spartina although these increases were not significant. Also, in the Spartina marsh, some heavy metals were concentrated in the surface layer of the sediment. The Spartina salt marsh in this study was only four years old; therefore, it is suggested that further study of this allen species on a longer time frame in the Jiangsu coastland should be carried out.

Species Exclusion Between an Invasive and an Indigenous Whitefly on Host Plants with Differential Levels of Suitability

The whitefly Bemisia tabaci has risen to international prominence since the 1980s due to the rapid spread around the globe by the two species B and Q within this species complex.The invasion of B has often been associated with the displacement of indigenous whiteflies.As the genetic structure of B.tabaci is diverse,more case studies of the competitive relationships between B and indigenous species of the whitefly species complex will help to understand further the mechanisms underlying the invasion of B.We examined the competitive interactions between B and ZHJ2,a widely distributed indigenous whitefly in Asia,on host plants with differential levels of suitability to the two species in the laboratory,and also tested the effect of insecticide application on the competitive relationships.Three species of plants were tested including cotton,a plant showing similar levels of suitability to both species,squash,a plant showing higher suitability to B than to ZHJ2,and kidney bean,a plant showing higher suitability to ZHJ2 than to B.In the case of no insecticide application,B displaced ZHJ2 on cotton,squash,and kidney bean by the 6th,3rd and 10th generation,respectively.With the application of imidacloprid,the displacement of ZHJ2 by B on cotton occurred by the 5th generation.As the displacement progressed,the proportion of B females increased,and the proportion of ZHJ2 females decreased on cotton and squash.In contrast,on kidney bean the proportion of B females remained unchanged while that of ZHJ2 increased.These results show the strong capacity of the invasive B to displace ZHJ2,and indicate that host plants with differential levels of suitability to the two species may affect the speed but not the trend of displacement and insecticide application may accelerate the process of displacement.

Treatment of Invasive Marine Species on Board by Using Micro-gap Discharge Plasma

A pilot-scale experiment of 20t/h for the treatment of ship＇s ballast water is reported in this paper. When the concentration of the dissolved OH. was 0.68 mg/L during the experiment, the rate of destroying bacteria, mono-algae, protozoan reached 100% within 2.67 s. The effect of hydroxyl radicals on biochemical processes was also studied. The attenuation rate of photosynthesis pigment was 100%. And the main reason for the cells＇ death was the strong destruction of the monose, amylose, protein, DNA and RNA in the cells. As an advanced oxidation method, the procedure can destroy invasive marine species when a ship is in the process of discharging its ballast water.