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A combination of ecophysiological features makes some invasive plants difficult to eradicate in Mediterranean-type ecosystems. The human footprint in these ecosystems increases propagule pressure, helps habitat fragmentation, and facilitates adaptation of these invasive plants. Citizen science is as important as fundamental science and environmental management by public authorities to prevent new invasions. An in-depth analysis of the mechanistic processes underlying the evolution and ecophysiology of typical invasive plants such as Carpobrotus spp., Acacia spp., Agave spp., and Opuntia spp. in Mediterranean-type ecosystems shows very sophisticated, complex, and efficient strategies for invasion success, particularly in fragmented habitats. Propagule pressure at both geographical and temporal scales and the establishment of long-term seed banks are determinant for invasion success. A two-sword strategy based on long-term prevention and eradication is proposed for the management of Mediterranean-type ecosystems. Eradication of invasive plants in Mediterranean-type ecosystems appears to be extremely difficult nowadays and, at least for some invaders like Carpobrotus spp., long-term approaches that ultimately culminate in the elimination of seed banks is the only path for success. [ABSTRACT FROM AUTHOR]

Simple Summary: The impact of parasitic plants on invasive plants varies depending on the parasitism time and species. Cuscuta australis is a common parasitic plant, while Xanthium spinosum and Xanthium italicum are invasive plants. The impact of parasitism on the competitive ability of invasive plants has been rarely reported. Therefore, in this study, we aim to investigate the impact of southern dodder parasitism on the competitive ability of X. spinosum and X. italicum. At the same time, we found that parasitism of southern dodder increased the competitive ability of X. spinosum and weakened the competitive ability of X. italicum. It is worth noting that invasive plants also provide a medium for the spread of southern dodder. Based on the research results, we suggest trying to prevent the same domain distribution of the two as much as possible to reduce the harm to local plants and crops. The competitive ability of invasive plants is a key factor in their successful invasion, and research on this ability of invasive plants can provide a theoretical basis for the prevention and control of invasive plants. This study used Cuscuta australis, Xanthium spinosum, and Xanthium italicum as research materials and conducted outdoor controlled pot experiments to compare and study the changes in the biomass, competitiveness, and growth cycle of X. spinosum and X. italicum parasitized by C. australis at different growth stages. The results showed that (1) parasitism by C. australis increased the biomass of X. spinosum and decreased that of X. italicum, but under parasitism, the root cap ratio of X. spinosum and X. italicum increased, and the fruit biomass ratio decreased, indicating that X. spinosum and X. italicum reduced the energy input for reproduction and increased the energy input for nutrient growth to resist the impact of C. australis parasitism; (2) the relative competitive intensity calculated based on the total biomass of a single plant showed a negative value for X. spinosum during parasitism at the flowering and fruit stages, indicating an increase in competitive ability, and X. italicum showed a positive value during parasitism at the seedling and flowering stages, indicating a decrease in competitive ability; and (3) the parasitism of C. australis significantly shortened the fruit stage of X. spinosum and X. italicum, leading to a significant advance in their flowering, fruiting, and fruit ripening times. Simultaneously, it significantly reduced the morphological indicators of biomass, plant height, and crown width. Thus, C. australis parasitism has a certain inhibitory effect on the competitive ability of some invasive plants and can shorten their growth cycle, the latter of which has an important impact on their reproduction and diffusion. [ABSTRACT FROM AUTHOR]

Transgenerational plasticity (TGP) allows a plant to acclimate to external variable environments and is a potential mechanism that explains the range expansion and invasion success of some exotic plants. Most studies explored the traits of TGP associated with the success of exotic plant invasions by comparison studies among exotic, native, invasive, and noninvasive species. However, studies on the TGP of invasive plants in different resource environments are scarce, and the biological mechanisms involved are not well understood. This study aimed to determine the role of TGP in the invasiveness of Xanthium strumarium in northeast China. We measured the plant morphology of aboveground parts and the growth of three generations of the invader under different environmental conditions. The results showed that the intergenerational plasticity of X. strumarium was stronger under stress conditions. We found that the X. strumarium parent generation (F0) grown under water and/or nutrient deficiency conditions transferred the environmental information to their offspring (F1 and F2). The F1 generation grown under high‐resource conditions has greater height with larger crown sizes, thicker basal diameters, and higher biomass. Both water and nutrients can affect the intergenerational transmission of plant plasticity, nutrients play a more important role compared with water. The high morphological intergenerational plasticity of X. strumarium under a pressure environment can help it quickly adapt to the new environment and accelerate the rapid expansion of the population in the short term. The root:shoot ratio and reproductive and nutrient distribution of the X. strumarium F0 and F1 generations showed high stability when the growth environment of the F0 generation differed from that of the F1 generation. The stable resource allocation strategy can ensure that the obtained resources are evenly distributed to each organ to maintain the long‐term existence of the community. Therefore, the study of intergenerational transmission plasticity is of great significance for understanding the invasion process, mechanism, and prevention of invasive plants. [ABSTRACT FROM AUTHOR]

Cenchrus spinifex is one of the invasive plant species in China, which seriously affects the animal husbandry and ecological environment in China.In order to predict the change of suitable distribution area of C. spinifex under future climate change scenarios, based on the MaxEnt model, this study used 103 geographical distribution data of C. spinifex and 19 climatic and environmental factors to analyze and predict the suitable distribution area of C. spinifex in China under two climate change scenarios of RCP2.6 and RCP8.5 in the 2050s and 2070s. The results were as follows:(1)The current suitable distribution area of C. spinifex occupied 4.00% of the study area, which was mainly distributed in Northeast China borderline by Inner Mongolia, Jilin and Liaoning.(2)Under the two future climate change scenarios, the suitable distribution areas for each grade of C. spinifex will expand to a certain extent compared with the current, and the medium suitable areas will expand the most, reaching 38.26%.(3)Annual mean temperature, standard deviation of seasonal temperature variation, and precipitation in the wettest season were the main climatic factors affecting the distribution of C. spinifex.(4)In the future, the distribution centroid of C. spinifex will generally move westward. The above results indicate that the current invaded areas of C. spinifex in China are far smaller than the potential invaded areas, and it may further spread to the arid and semi-arid regions in China. In order to prevent the harm caused by the widespread spread of C. spinifex in northern China, we need to focus on its preventive measures and invasion situation in the future. The results of this study provide important theoretical basis and control methods for the prevention and control of invasive plants in China. [ABSTRACT FROM AUTHOR]

Effective management of invasive plants conserves biodiversity values, reduces economic costs, and minimizes negative impacts on human health. Fostering people's awareness of invasive plants is one of the most cost-effective approaches in preventing the spread and introduction of invasive plants. Therefore, this study aims to understand (1) people's knowledge and risk perceptions, (2) associations between risk perceptions and demographics, and (3) people's willingness to support current management strategies in the Metro Vancouver region, British Columbia, Canada. An online survey was carried out and received 356 responses across the region. We found that people's knowledge and risk perceptions of invasive plants were ecologically oriented. Older respondents perceived higher risks of invasive plants. Among respondents of the same age, annual income higher than $50,000 was associated with higher levels of risk perception. Respondents who had professional and/or recreational group memberships perceived higher economic risks. Respondents highly supported activities that they could take part in directly, such as community invasive pulls and native species planting. Overall, our findings aid managers in allocating appropriate funding or tailoring outreach efforts to different aspects of invasive plants as well as groups/communities where people's knowledge and risk perceptions of invasive plants are low. Highlights: People's knowledge and risk perceptions of invasive plants were ecologically oriented. Age and income were positively associated with perceived risks of invasive plants. Respondents who had professional/recreational group memberships perceived higher risks of invasive plants. Respondents supported local governments to spend funds on active management activities. [ABSTRACT FROM AUTHOR]

Pokeweed (Phytolacca americana L.) is an invasive weed commonly found in the Oltenia area (Romania). Considering the economic importance of maize crop, this study was carried out to investigate the phytotoxic, cytotoxic and genotoxic potential of pokeweed extracts on maize (Zea mays L.). The seeds of maize were treated with different concentrations (5%, 10% and 20%) of pokeweed extracts, under laboratory conditions, for macroscopic and microscopic analyses, respectively. A control (distilled water) was used for comparison. All extracts significantly decreased germination, root and shoot length of maize seedling, also inhibited root cell division by the reduction of the mitotic index and by the induction of chromosomal and nuclear abnormalities in the root cells of maize. Chromosome stickiness, C-mitosis, piknosis, laggards, micronuclei and nuclear erosion, were observed. Thus, the present study suggests that the allelochemicals in the extracts of P. americana have a highly toxic potential on maize, so prevention and control of this invasive plant in the agricultural fields, are really necessary. [ABSTRACT FROM AUTHOR]

This review summarizes all known direct nontarget attack (NTA) cases of intentionally released or actively redistributed weed biological control agents, in order to allow for an objective risk-benefit analysis when choosing the most appropriate method for controlling invasive plants. Of 457 agents intentionally released until 2008, 60 (13.1%) have been recorded attacking nontarget species in the field. Of 1517 releases made using the 457 agent species, 122 (8.0%) resulted in NTA. Both proportions have declined over time. Three-quarters of all NTA cases occurred on plant species in the same family as the target weed. Approximately one-half of NTA cases were predicted/predictable. In the majority of unpredicted cases (93.5%), the respective nontarget plant species had not been tested prerelease. There were only four cases of "false negatives" (less than 1%), where the impacted plant species had been tested prerelease and deemed not at risk. The incidences of unpredicted nontarget attack of intentionally released weed biocontrol agents decreased over time and this trend is thought to continue with scientific advancements. What is most needed is more systematic postrelease monitoring to compare with prerelease host range testing to further advance the predictability of host use of biocontrol agents. [ABSTRACT FROM AUTHOR]

Two common Potamogeton species, Potamogeton pectinatus L. and Potamogeton crispus L., were collected in 2016 and 2017 from a lowland, sandy bed in the Wilga River in Poland to investigate the ability of the plants to adapt to changing hydrological conditions. Measurements included biomechanical properties as well as the morphological characteristics of their stems. Specifically, experiments included three-point bending and tension tests as well as stem diameter and cross-sectional morphology at various periods in the plants' life cycles. Detailed information about the seasonal changes in biomechanical traits and the similarities between the two investigated plants are presented. The data show significant differences in the three-point bending and tension parameters. The flexural rigidity proved to be the most sensitive parameter to changes in hydrological conditions during the season. The maximum forces in the three-point bending tests needed to complete the fracture of P. crispus were much higher, reaching values up to 0.097 N, than those for P. pectinatus (0.035 N), due to P. crispus having thicker shoots, which resulted in greater resistance to elastic deformity. Moreover, the modulus of elasticity values shows that P. pectinatus is much more prone to return to its original shape after the removal of the acting forces. For instance, the maximum Young's modulus for P. pectinatus was 116.23 MPa, whereas for P. crispus, the highest value was four times lower (26.60 MPa). The present study supplements an aquatic plant biomechanics database that has been created in recent years. [ABSTRACT FROM AUTHOR]

A microwave‐based process to control invasive species (seeds and adult stages) in the field prior to plant community restoration is currently under development. We investigated the effect of four microwave treatment pairings of Power × Duration (2kW4min, 4kW2min, 2kW8min, and 4kW4min) on seedling emergence of (1) an abandoned field seed bank used as a model for various plant species and (2) seeds of three species invasive in Europe: Datura stramonium (Jimson weed), Reynoutria × bohemica (Bohemian knotweed), and Solidago gigantea (Giant goldenrod). In addition, we assessed whether nontreated seeds of these three invasive species could germinate on microwave‐treated soils. As microwave soil heating usually leads to nonhomogeneous temperatures within a sample, we also assessed whether the position of seeds in the soil during microwave treatment (center vs. edges) impacted seedling emergence. Results show that the most intensive microwave treatments (2kW8min and 4kW4min), enabling the soil to reach 85°C, are highly effective in inhibiting seedling emergence of invasive species and the seed bank. The 2kW8min treatment, combining lowest power and longest exposure, is the most effective, reducing seed bank seedling emergence by 98% compared to control. The results also reveal a species‐specific response to heat, and lower microwave effectiveness on seeds located at the soil surface, which may explain the incomplete effectiveness of intensive treatments. Our results also suggest that prior microwave soil treatment does not prevent a considerable proportion of newly arrived invasive species seeds from germinating, suggesting that this method should be followed by restoration of native plant cover. [ABSTRACT FROM AUTHOR]

The use of non-standardized inverse time curves for improving overcurrent relay coordination performance is presented in this paper. Since the use of same curve type does not guarantee curve-intersection-free in meshed systems, numerous violations of coordination constraints may appear. Hence, non-conventional time curves offer altenative solution as time curve design is determined for each relay coordination pair problem. The model and implementation of optimization algorithm for coordination must be capable of handling increased problem dimension and constraints. Also, different short circuit currents must be taken into account to guarantee the relay coordination over the entire coordination interval. The invasive weed optimization (IWO) algorithm has been adapted for the high dimension coordination problem and has been tested on several IEEE systems. Overall results expose the enhancement of relay coordination when using non-standardized inverse time curves and IWO. [ABSTRACT FROM AUTHOR]

This study develops a mixed, systematic, low-cost methodology to define and map native vegetation and the spread of the most aggressive invasive species in islands biomes, focusing on the Galápagos National Park (GNP). Based on preliminary legends defined by experts, Landsat 8/OLI fusion imagery was used for object-oriented classification to obtain the vegetation map of this archipelago. This technique was later verified and validated using high-resolution images from unmanned aerial vehicles (UAVs, i.e., drones) and dedicated satellites, ground truthing, and visual confirmation around GNP coasts. This mixed methodology allowed mapping of nine native ecosystems, six invasive-dominated vegetation units, and two types of lavas. Around 53.63% of GNP is covered by native ecosystems and ∼2.2% is “canopy” dominated by invasive species to date. Native-dominated deciduous forest types cover ∼40.8% of the GNP and only ∼12.8% of the protected area is nowadays covered by humid and transitional type native ecosystems. Among humid native ecosystems, those distributed in the highlands only cover 4.8% and are highly threatened by invasive species, which are mostly distributed in these summit areas. Of the five islands (out of 18) recording invasive-dominated units, Isabela and Santa Cruz were the most infested. Cedrela odorata, Pennisetum purpureum, and Psidium guajava were the main invasive plants dominating the GNP canopy. Highly noxious Rubus niveus was the only invasive species dominating areas among the five infested islands. Methodology detailed here proved useful to provide accurate spatially-explicit islands vegetation data, potential for replication in time, and is expected to aid suitable management of highly endangered and unique biotas in this and other tropical island biomes. [ABSTRACT FROM AUTHOR]

Summary: The perennial shrub Siam Weed (Chromolaena odorata (L.) R. M. King & H. Rob.), a native of the rainforests of central and southern America, is predicted to invade most countries between the Tropics of Cancer and Capricorn. Subsequent to its discovery in northern Queensland, Australia in 1994, it was unsuccessfully targeted for eradication, with early control efforts restricted to manual removal and foliar spraying with triclopyr/picloram. A chemical trial involving five herbicides and three application methods (foliar, basal bark and cut stump) was undertaken in northern Queensland to identify effective chemicals to control this weed. Of the foliar herbicides tested, fluroxypyr (70 g/100 L) provided 99% mortality, triclopyr/picloram (105/35 g/100 L) 95%, while metsulfuron‐methyl (9 g/100 L) killed 85% of the treated plants. The herbicides fluroxypyr (300 g/100 L), picloram (43 g/1 kg) and triclopyr/picloram (400/200 g/100 L) killed greater than 98% of the plants when applied as basal bark or cut stump. The integration of fire into the management strategy either as a primary or secondary control option could have a major role, given that in this study, 99% of the Siam Weed soil seed bank was located on the soil surface. [ABSTRACT FROM AUTHOR]

Spartina alterniflora has become the main invasive plant along the Chinese coast and now threatens the local ecological environment. Accurately monitoring the distribution of S. alterniflora is urgent and essential for developing cost-effective control strategies. In this study, we applied the One-Class Classification (OCC) methods of Maximum entropy (Maxent) and Biased Support Vector Machine (BSVM) based on Landsat time-series imagery to detect the species on the middle coast of Jiangsu in east China. We conducted four experimental setups (i.e., single-scene analysis, time-series analysis, Normalized Difference Vegetation Index (NDVI) time-series analysis and a compressed time-series analysis), using OCC methods to recognize the species. Then, we tested the performance of a compressed time-series model for S. alterniflora detection and evaluated the expansibility of this approach when it was applied to a larger region. Our principal findings are as follows: (1) Maxent and BSVM performed equally well, and Maxent appeared to have a more balanced performance over the summer months; (2) the Maxent model with the Default Parameter Set (Maxent-DPS) showed a slightly higher accuracy and more overfitting than Maxent with the Akaike Information Criterion corrected for small samples sizes (AICc)-selected parameter set model, but a t-test found no significant difference between these two settings; (3) April and December were deemed to be important periods for the detection of S. alterniflora; (4) a compressed time-series analysis model--including only three variables (December NDVI, March green and the third Principal Component in January, PC3)--yielded higher accuracy than single-scene analyses, which indicated that time-series analysis can better detect S. alterniflora than single-scene analyses; and (5) the Maxent model using the reconstructed optimal variables and 70 training samples over a larger region produced encouraging results with an overall accuracy of 90.88% and a Kappa of 0.78. The one-class classification method combined with a phenology-based detection strategy is therefore promising for the application of the long-term detection of S. alterniflora over extended areas. [ABSTRACT FROM AUTHOR]

Alien plant invasions are a major threat to biodiversity and ecosystem functioning in South Africa's Cape Floristic Region (CFR). Large-scale government-funded management initiatives are underway to reduce the extent of invasions in this region. Among the many challenges are the huge spatial extent of the invasions and difficulties in coordinating management efforts across large areas of invaded land in private ownership. Very little information is available on the success of privately-funded alien plant control initiatives. This study investigated the effectiveness of one large project in reducing alien plant cover, the challenges faced and the costs associated with long-term clearing operations on privatelyowned land in the CFR. Results for the study area (Vergelegen) show that the cover of dense invasive plant stands declined by 70% over 10 years since management operations began, but that operations cost 3.6 times more than was originally estimated (ZAR 43.6 vs 12.19 million, respectively). The challenges associated with managing invasive alien plants (IAPs) on private land are very similar to those faced on state-owned land, with the efficiency of management being constrained by multiple interacting environmental and socio-economic factors. However some success in managing IAPs can be achieved by adhering to basic principles, including careful planning with clear achievable goals in mind, a commitment to stable long-term funding and regular monitoring. Most private land owners cannot afford the substantial investment of resources that would be required to clear large stands of IAPs and to ensure that cleared areas are maintained to prevent re-invasion, and finding ways to fund this remains a challenge. [ABSTRACT FROM AUTHOR]

The present study reports the herbicidal activity of metribuzin and tribenuron-methyl embedded in the degradable matrix of natural poly-3-hydroxybutyrate [P(3HB)/MET and P(3HB)/TBM]. The developed formulations were constructed as films and microgranules, which were tested against the weeds such as white sweet cloverMelilotus albusand lamb's quartersChenopodium albumin the presence of soft spring wheat (Triticum aestivum, cv. Altaiskaya 70) as the subject crop for investigation. The activity was measured in laboratory scale experiments by determining the density and weight of the vegetative organs of weeds. The study was also aimed at testing the effect of the experimental formulation on the growth of wheat crop as dependent on the method of herbicide delivery. The experimental MET and TBM formulations showed pronounced herbicidal activity against the weed species used in the study. The effectiveness of the experimental formulations in inhibiting weed growth was comparable to and, sometimes, higher than that of the commercial formulations (positive control). The amount of the biomass of the wheat treated with the experimental herbicide formulations was significantly greater than that of the wheat treated with commercial formulations. [ABSTRACT FROM PUBLISHER]

South Africa has a major problem with invasive plant species. Many species have long residence times, are well established, and have large invasive ranges, whereas others are still in the early stages of invasion. Predicting the full extent of invasions for species that have only recently started spreading is important for guiding management strategies. Ailanthus altissima is a widespread invasive species in many parts of the world. Although it has had a long residence time in South Africa, it is yet to replicate the extent of invasiveness and major impacts reported for the species in other parts of its adventive range. We mapped the countries in which A . altissima has been reported and evaluated the invasion status of the species in each (i.e. the position of the species on the introduction-naturalization-invasion continuum as conceptualized by Richardson and Pyšek, 2012). We then mapped the current distribution in more detail for South Africa. The species is known to be present in at least 51 countries and is invasive in 23 countries. Ailanthus altissima is present in all South African provinces except Limpopo and is most common and abundant in the Western Cape, Gauteng, Eastern Cape, and the Free State. We applied species distribution modelling using global distribution data to determine parts of the world, and in particular regions within South Africa, that are climatically suitable for the species. Large parts of Africa are potentially invasible by this species. Seven regions in South Africa were identified as high-risk areas for invasion by A . altissima . The species is already far too widespread in South Africa for eradication at the national scale to be feasible. A national strategy for managing the species should focus on: 1) early detection and rapid response in areas identified as climatically suitable and where the species is not already present; and 2) local and regional-scale initiatives based on objective prioritization in terms of feasibility of management success and asset protection. [ABSTRACT FROM AUTHOR]

Invasive alien plants that have seeds with innate dormancy, and thus large, persistent soil-stored seed banks, are particularly difficult to manage. Dormant seeds typically require specific stimuli as cues for germination, resulting in mass recruitment. Sound understanding of germination stimuli may provide options to aid the management of invasives. We investigated the response of two invasive trees, Acacia mearnsii and A. melanoxylon , and an indigenous ecological analogue, Virgilia divaricata , to different germination stimuli (chipped (manually), hot water exposure, dry heat pulse, smoke, and no treatment) at two temperature regimes (winter ~ 12 °C and summer ~ 20 °C) to explore how their germination requirements may be used to favour V. divaricata in areas cleared of the invasives. Chipped and hot water exposure resulted in the highest germination in all three species. Virgilia divaricata responded marginally better than the invasives to the dry heat pulse, particularly at 20 °C. However, the three species mostly responded comparably to the stimulus–temperature combinations, suggesting that manipulation of stimuli is not a feasible option for management of the invasives at a large scale. In the absence of any stimulus (~ akin to conditions associated with aboveground clearing of alien vegetation cover), germination was poorer in V. divaricata than in the invasive species especially at 20 °C, providing motivation for focusing Acacia management operations in cooler seasons in areas where V. divaricata seed banks occur. Another option is to sow V. divaricata seeds that have been chipped or exposed to hot water in areas cleared of the invasives of which the seeds would not have received stimuli. [ABSTRACT FROM AUTHOR]

The Global Biodiversity Information Facility (GBIF) is at the moment one of the largest and most widely used biodiversity databases. Nevertheless, there are still some limitations, e.g. in terms of plant species status (native vs. non-native) and geographic resolution of records. At the same time, it is well known that alien plant invasions in inland freshwaters can alter community structure, ecosystem functions and services with significant negative impacts on biodiversity and human activities. We assessed if the GBIF database has a geospatial homogeneous information for native and non-native aquatic plant species for South America and whether or not literature resources not yet digitalized (floras, checklists and other papers) could provide additional information. We selected a set of 40 native and 40 non-native aquatic species. These 80 species included a sub-set of 40 alien species previously evaluated with the USAqWRA scheme (US Aquatic Weed Risk Assessment). Species with non-reliable identification, duplicates of the same collection, records poorly georeferenced were removed from the dataset. New records were manually compiled through classical literature research. All the georeferenced records (GBIF + literature) were used for the mapping and the comparative analysis. As a result, we can conclude that the two datasets provide quite significantly different information and the combination of the two offers new information that would not exist in a single data source. Nevertheless, a careful [ABSTRACT FROM AUTHOR]

Understanding causes of species invasiveness is a necessary condition for effective mitigation of invasive species. One of the key characteristics supporting species invasiveness may be species ability to adapt to wide range of environmental conditions. It has been hypothesized that increased ability to adapt to wide range of conditions may be related to polyploidization. Experimental studies comparing the ability to adapt to novel conditions between native and invasive populations of different cytotypes of the same species are, however, still largely missing. We used Vicia cracca , a species known to occur in two different cytotypes in its native range in Europe and being an important invader in North America. We investigate if known cytotypes of Vicia cracca from the native and invasive range differ in their ability to adapt to environmental variation. To do this, we grew plants of both cytotypes from the native and invasive range in a common garden and exposed half of the plants to experimental shading to simulate environmental variation potentially occurring at the localities of the species. The study confirmed previous expectation that only polyploid plants occur in the invasive range. The study, however, did not support the expectation that the tetraploids would be superior to the diploids from the native range or have better ability to cope with shading. The performance and plasticity of tetraploids from the invasive range was in most cases different from the European tetraploids and differed between the two areas in the invasive range. This may suggest that the tetraploids underwent strong post-invasive evolution and have adapted in different ways to the specific condition of the different parts of the invaded area. Alternatively, it may indicate that the invasive range was created by colonizers from different areas possessing distinct adaptations. [ABSTRACT FROM AUTHOR]

Invasive alien plant species threaten native biodiversity, disrupt ecosystem functions and can cause large economic damage. Plant invasions have been predicted to further increase under ongoing global environmental change. Numerous case studies have compared the performance of invasive and native plant species in response to global environmental change components (i.e. changes in mean levels of precipitation, temperature, atmospheric CO2 concentration or nitrogen deposition). Individually, these studies usually involve low numbers of species and therefore the results cannot be generalized. Therefore, we performed a phylogenetically controlled meta-analysis to assess whether there is a general pattern of differences in invasive and native plant performance under each component of global environmental change. We compiled a database of studies that reported performance measures for 74 invasive alien plant species and 117 native plant species in response to one of the above-mentioned global environmental change components. We found that elevated temperature and CO2 enrichment increased the performance of invasive alien plants more strongly than was the case for native plants. Invasive alien plants tended to also have a slightly stronger positive response to increased N deposition and increased precipitation than native plants, but these differences were not significant (N deposition: P = 0.051; increased precipitation: P = 0.679). Invasive alien plants tended to have a slightly stronger negative response to decreased precipitation than native plants, although this difference was also not significant ( P = 0.060). So while drought could potentially reduce plant invasion, increases in the four other components of global environmental change considered, particularly global warming and atmospheric CO2 enrichment, may further increase the spread of invasive plants in the future. [ABSTRACT FROM AUTHOR]

Parasitic Echinochloa colona (L.) Link has globally invaded paddy fields that could devote to severe grain yield loss. Prolonged extensive application of commercial synthetic herbicides could pose the weed evolved resistance, bioaccumulation and environmental deterioration. Hence, this paper pertains to the aim of investigating potent natural products which have shown considerable phytotoxic activities, subsequent phytotoxin studies and extraction optimization for pre-emergent control of E. colona . In the phytotoxicity study, a suite of invasive plants was procured and the leaf, stem and root extracts were evaluated by in vitro germination and seedling growth assays. The invasive plant extracts exhibited multiple magnitudes of inhibition against E. colona in the plant species-, plant part- and concentration-dependent manners. Along with the dose-response study, the leaf extracts of Mikania micrantha Kunth ex H.B.K., Clidemia hirta (L.) D. Don , Dicranopteris linearis (Burm.f.) Underw. and Ageratum conyzoides L. showed the attainable half maximal effective doses ( ED 50 ) below the concentration 100 g biomass dry weight equivalent (BDWE)/L, indicating the top-ranked inhibition of E. colona among the investigated plant extracts. The top-ranked phytotoxic leaf extracts were subjected to qualitative and quantitative characterizations including extraction yield, total phenolic content, phytochemical screening and spectroscopic analysis of the phytochemicals with possible inhibitory effect. Joint putative allelochemicals consisting of 16 phenolics and 5 aromatics were detected concurrently by liquid chromatography-mass spectrometry (LC-MS), were found contributed to the appreciable germination inhibition. Amongst the abundant phenolic acids were protocatechuic acid, gallic acid, p -hydroxyphenylacetic acid and chlorogenic acid. To suit the industrial desire in product development, the phytotoxic leaves were processed through extraction optimization using response surface methodology (RSM). A multivariate face-centered cube design (FCCD) was established to seek the functional relationship between the process variables (extraction time, agitation speed and solvent consumption) and the response (germination inhibition). Quadratic response surface models were obtained with the models significance and significant effect of the process factors at 95% confidence interval were examined by various statistical analyses. Verification experiments at the optimal conditions were well matched with the predicted values, along with absolute errors in the range 3.63% to 6.70%, indicating the proposed quadratic models were valid and useful prediction of the extraction conditions. These outcomes provide the valuable findings on the possible use of potent invasive plants as bioeffective, economical and eco-friendly herbicide alternative towards fostering the sustainable weed management. [ABSTRACT FROM AUTHOR]

Based on concerns that useful weed diversity in agroecosystems as well as associated traditional knowledge may be declining due to agricultural intensification and indiscriminate eradication of weeds, we studied weed diversity and use by local ethnic groups in tea plantations in northern Thailand under different agricultural intensities and landscape complexities, namely agroforestry, organic, and Good Agricultural Practice (GAP) based conventional system. In each system, we sampled five tea plantations using belt-transects of 25 m. Use data were collected through interviews with specialist informants. We recorded 214 weed species (gamma-diversity) of which 66 were useful. Agroforestry system had the highest alpha- and beta-weed diversity, suggesting that the low agricultural intensity and high landscape complexity in this system is associated with higher weed diversity in tea plantations. The common weed species were clearly different in the three systems and only a small fraction (22 species) of widespread weeds was shared among them, resulting in low weed similarity between systems. The 66 useful species of weeds were mostly for food and medicine. Uses of some weeds were shared between systems. Many of the useful weeds are invasive species, suggesting that they are prevalent and inexpensive plant resources for rural people and could represent alternative resources in the future. Because the occurrence of invasive weeds may affect the natural habitats of the native flora, integrating the exploitation of weeds into weed management strategies may reduce the weed population while sustaining agrobiodiversity and conserving associated traditional knowledge in the long term. [ABSTRACT FROM AUTHOR]

Managing intentional species introductions requires evaluating potential ecological risks. However, it is difficult to weigh costs and benefits when data about interactions between novel species and the communities they are introduced to are scarce. In anticipation of expanded cultivation of perennial biomass crops, we experimentally introduced Miscanthus sinensis and Miscanthus x giganteus (two non-native candidate biomass crops) into two different non-crop habitats (old field and flood-plain forest) to evaluate their establishment success and impact on ambient local communities. We followed these controlled introductions and the composition dynamics of the receiving communities over a 5-year period. Habitats differed widely in adult Miscanthus survival and reproduction potential between species, although seed persistence and seedling emergence were similar in the two biomass crops in both habitats. Few introductions survived in the floodplain forest habitat, and this mortality precluded analyses of their potential impacts there. In old field habitats, proportional survival ranged from 0.3 to 0.4, and plant survival and growth increased with age. However, there was no evidence of biomass crop species effects on community richness or evenness or strong impacts on the resident old field constituents across 5 years. These results suggest that Miscanthus species could establish outside of cultivated fields, but there will likely be a lag in any impacts on the receiving communities. Local North American invasions by M. sinensis and M. sacchariflorus display the potential for Miscanthus species to develop aggressively expanding populations. However, the weak short-term community-level impacts demonstrated in the current study indicate a clear management window in which eradicating species footholds is easily achieved, if they can be detected early enough. Diligent long-term monitoring, detection, and eradication plans are needed to successfully minimize harmful invasions from these biomass crops. [ABSTRACT FROM AUTHOR]

Globally, Phytophthora cinnamomi is listed as one of the 100 worst invasive alien species and active management is required to reduce impact and prevent spread in both horticulture and natural ecosystems. Conversely, there are regions thought to be suitable for the pathogen where no disease is observed. We developed a climex model for the global distribution of P. cinnamomi based on the pathogen's response to temperature and moisture and by incorporating extensive empirical evidence on the presence and absence of the pathogen. The climex model captured areas of climatic suitability where P. cinnamomi occurs that is congruent with all available records. The model was validated by the collection of soil samples from asymptomatic vegetation in areas projected to be suitable by the model for which there were few records. DNA was extracted, and the presence or absence of P. cinnamomi was determined by high-throughput sequencing ( HTS). While not detected using traditional isolation methods, HTS detected P. cinnamomi at higher elevations in eastern Australia and central Tasmania as projected by the climex model. Further support for the climex model was obtained using the large data set from south-west Australia where the proportion of positive records in an area is related to the Ecoclimatic Index value for the same area. We provide for the first time a comprehensive global map of the current P. cinnamomi distribution, an improved climex model of the distribution, and a projection to 2080 of the distribution with predicted climate change. This information provides the basis for more detailed regional-scale modelling and supports risk assessment for governments to plan management of this important soil-borne plant pathogen. [ABSTRACT FROM AUTHOR]

[Display omitted] • Urban riparian corridors have a positive effect on the spread of spontaneous plants. • The functional traits of plants responded significantly to the landscape structure. • The dispersal ability is related to the scale of plant response to landscape pattern. The loss of biodiversity due to rapid urbanization can be mitigated by urban riparian corridors. As an important component of urban biodiversity, spontaneous herbaceous plants play an essential role in the ecological functions of urban river corridors. Currently, the influence of the landscape structure within corridors on plant diversity has been poorly understood. In this study, we investigated the species and functional diversity, especially the functional traits of origin, pollination, and dispersal, of spontaneous herbaceous plants in the Wenyu River-North Canal riparian corridor in Beijing. The results showed that urban riparian corridors have a positive effect on the spread of alien and invasive plants as well as increasing the native plant diversity. No significant differences in diversity indicators but significant differences in the composition of functional traits between habitat types. Plants with long pollination and dispersal distances tended to be more closely related to the landscape structure indices at larger scales. Invasive plants were more common in patches with significant connectivity, while native plants were positively correlated with water and road connectivity. Anemophilous and anemochores were more common in habitats with sinuous edges. Ant-dispersed plants were closely related to the water bodies. Autochores were positively correlated with the connectivity of habitat patches. Plants dispersed by birds and mammals were weakly correlated with landscape structure. Our study underlines that emphasis should be placed on the support for plant pollination and dispersal, together with the prevention and control of invasive plants in the construction and management of future urban ecological corridors. [ABSTRACT FROM AUTHOR]

When faced with a large species pool of invasive or potentially invasive alien plants, prioritization is an essential prerequisite for focusing limited resources on species which inflict high impacts, have a high rate of spread and can be cost-effectively managed. The prioritization process as detailed within this paper is the first tool to assess species for priority for risk assessment ( RA) in the European Union ( EU) specifically designed to incorporate the requirements of EU Regulation no. 1143/2014. The prioritization process can be used for any plant species alien to the EU, whether currently present within the territory or absent. The purpose of the prioritization is to act as a preliminarily evaluation to determine which species have the highest priority for RA at the EU level and may eventually be proposed for inclusion in the list of invasive alien species of EU concern. The preliminary risk assessment stage (Stage 1), prioritizes species into one of four lists (EU List of Invasive Alien Plants, EU Observation List of Invasive Alien Plants, EU List of Minor Concern and the Residual List) based on their potential for spread coupled with impacts. The impacts on native species and ecosystem functions and related ecosystem services are emphasized in line with Article 4.3(c) of the Regulation. Only those species included in the EU List of Invasive Alien Plants proceed to Stage 2 where potential for further spread and establishment coupled with evaluating preventative and management actions is evaluated. The output of Stage 2 is to prioritize those species which have the highest priority for a RA at the EU level or should be considered under national measures which may involve a trade ban, cessation of cultivation, monitoring, control, containment or eradication. When considering alien plant species for the whole of the EPPO region, or for species under the Plant Health Regulation, the original EPPO prioritization process for invasive alien plants remains the optimum tool. [ABSTRACT FROM AUTHOR]

A personal narrative is presented which explores the author's experiences of traveling to Singapore, Malaysia and Hong Kong, China as part of her collection trip to find insects that can be used to stop the increase of invasive plants.

Arbuscular mycorrhizal (AM) fungi can improve restoration outcomes by facilitating establishment of native plants. Yet, we know little about the effects of restoration methods on AM fungi. We examined how using herbicide and mowing to remove invasive Brassica nigra (black mustard) might alter AM abundance in a coastal sage scrubland. Black mustard is a non-mycorrhizal plant th a t produces allelochemicals th a t in h ib it AM fungi. Although black mustard removal could potentially improve AM growth, herbicide and mowing might harm AM fungi. We measured black mustard cover, AM hyphal abundance, and native plant cover from plots exposed to either herbicide or mowing versus untreated controls. We found th a t both herbicide and mowing reduced black mustard cover. Furthermore, herbicide increased AM abundance in one field site, potentially because herbicide killed black mustard roots and reduced allelochemical production. However, neither restoration treatment improved native plant abundance over the course of our study. Overall, herbicide can deter black mustard invasion and help re-establish the AM community in certain ecosystems, butwithout a corresponding increase in native plants. [ABSTRACT FROM AUTHOR]

The regulation and management of alien species can be contentious, particularly when the stakeholders who benefit from alien species are different from those who suffer the costs. We propose a consultative process involving relevant stakeholders in invasive species management decisions. The process involves (1) the identification of relevant stakeholders, (2) assessing their perceptions, (3) enhancing interaction between stakeholders, (4) assessing changes in stakeholders' perceptions following interactions with other stakeholders, and (5) developing management recommendations in collaboration with stakeholders. We demonstrate the application of the process using the family Cactaceae ('cacti') in South Africa. Many species of cacti have been introduced to the country over the past two centuries, mostly for horticulture, food and fodder, and hundreds of other species have been introduced in the past few decades (or are likely to be introduced soon) for horticulture. Using the proposed process enabled the negotiation and participation of all stakeholders in decision making and helped minimize contentious situations by clarifying stakeholder's beliefs and exploring consensus solutions. Consequently, management objectives were broadly supported by all stakeholders. These results will be included in a national cactus management strategy for South Africa. [ABSTRACT FROM AUTHOR]

Question: Planting or seeding native species after control of invasive species can limit re-invasion and hasten establishment of native species. Ruellia simplex (Mexican petunia) invades floodplain forests in Florida, and is controlled with glyphosate herbicide. Will herbicide application used to control this weed allow establishment of native vegetation and limit R. simplex? Location: Floodplain forest altered by stormwater run-off, Lake Jesup Conservation Area, Sanford, FL, US. Methods: We evaluated re-vegetation following herbicide application to control R. simplex. For re-vegetation, we planted or seeded native species (Andropogon glomeratus, Juncus effusus, Panicum longifolium, Solidago fistulosa) and measured stem density, percentage cover, above-ground biomass and species richness for 1 yr. We compared the results to those from control plots (i.e. no herbicide, no re-vegetation) and plots where R. simplex was sprayed with herbicide but not planted or seeded with native species. Results: Unassisted re-colonization (i.e. plots where R. simplex was sprayed but not planted or seeded with native species) did not result in native plant restoration. Re-vegetation treatments (i.e. plots where R. simplex was sprayed and planted or seeded with native species) did not restore native vegetation; nor did re-vegetation treatments reduce R. simplex stem density, percentage cover or biomass compared to control plots. However, total species richness, including native and exotic species richness, increased in plots planted with a native plug mix compared to control plots (i.e. no herbicide, no re-vegetation). Native species failed to germinate in all seeding treatments. Plugs had adequate survival (2-57% depending on species) but did not prevent re-invasion of R. simplex. Re-invasion of R. simplex occurred in plots despite application of glyphosate herbicide and re-vegetation treatments. Conclusions: Re-vegetation by seeding or planting did not establish native vegetation in the first year, instead, R. simplex reinvaded. Abiotic and biotic site conditions, e.g. invasive species propagule pressure and altered soil nutrients, may have limited seed germination and survival of planted seedlings. More research is necessary to determine if a reduction in invasive species propagules through repeated herbicide application coupled with planting native species results in native plant restoration in the longer term. [ABSTRACT FROM AUTHOR]

This paper summarizes the strategies of the San Francisco Bay Area Early Detection Network (BAEDN). BAEDN coordinates and implements Early Detection of and Rapid Response to infestations of target invasive plants throughout the nine county San Francisco Bay Area. Limited-distribution invasive plant species in the Bay Area were identified by analyzing occurrence records within the Calflora database. Target species were then prioritized according to whether or not they were documented as invasive and by expert opinion. Weed Heuristics: the Invasive Population Prioritization for Eradication Tool was used to prioritize the 272 known occurrences of the 73 target priority species based on relative impact, invasiveness, and feasibility of treatment. BAEDN coordinated two years of removal of these populations. Lessons learned and next steps are reviewed. As new populations and species are identified additional funds are needed to carry out coordinated evaluation, prioritization, and control efforts. [ABSTRACT FROM AUTHOR]

In North America host-specific flea beetles ( Aphthona spp.; Coleoptera: Chrysomelidae) from Europe have been introduced to suppress invasive populations of the exotic forb, leafy spurge, Euphorbia esula L. (Euphorbiaceae). Long term outcomes of such introduction were examined in 2013 for a spurge infested site (managed as elk winter range) in the mountain foothills of northern Utah where three species of flea beetles had been released two decades earlier, in the 1990s. The abundance of leafy spurge at the site had declined by 2013 to only 4% of its abundance in 1995. The three species of flea beetles (dominated by A. lacertosa Rosenhauer) persisted in low numbers at the site in 2013 [peaking at 7-8 adults (all species combined) per 100 stems and inflicting aboveground feeding damage to all spurge stems by late summer]; flea beetle abundance had declined by 89-97% from high numbers as sampled in 2001. Another biocontrol insect, the stem borer Oberea erythrocephala Schrank (Coleoptera: Cerambycidae), had immigrated on its own to the site (as first detected in 2008) and, by mid-July in 2013, had damaged all spurge stems (typically causing total loss of the inflorescence on flowering stems). With the collapse of the spurge population at the site, the biomass of grasses [dominated by the exotic Bromus inermis Leyss and Arrhenatherum elatius (L.)] and forbs increased by 269% and 507%, respectively, from 1995 to 2013. These increases in grasses and forbs at the site with insect suppression of leafy spurge have resulted in more favorable habitat for elk and other wildlife. [ABSTRACT FROM AUTHOR]

Echinochloa pyramidalis (Lam.) Hitchc. & Chase is an African grass with C4 photosynthesis, high biomass production, and high vegetative propagation that is tolerant to grazing and able to grow in flooded and dry conditions. Thus, it is highly invasive in tropical freshwater marshes where it is intentionally planted by ranchers to increase cattle production. This invasion is reducing plant biodiversity by increasing the invader's aerial coverage, changing wetland hydrology and causing soil physicochemical changes such as vertical accretion. Reducing the dominance of this species and increasing the density of native wetland species is a difficult, expensive, and time-consuming process. We applied a series of disturbance treatments aimed at eliminating E. pyramidalis and recovering the native vegetation of a partially invaded freshwater marsh. Treatments included physical (cutting, soil disking, transplanting individuals of the key native species Sagittaria lancifolia subsp. media (Micheli) Bogin, and/or reducing light with shade mesh) and/or chemical (spraying Round-Up™ herbicide) disturbances. At the end of the experiment, four of the five treatments used were effective in increasing the cover and biomass of native species and reducing that of E. pyramidalis. The combination of these treatments should be used to generate a proposal for the restoration of tropical wetlands invaded by non-native grasses. A promising treatment is using soil disked to soften the soil and destroy belowground structures such as roots and rhizomes. This treatment would be more promising if combined with the use of shade cloth. If it is desirable not to impact the soil or if there is not enough budget to make an effort to include active restoration disking soil, the use of shade cloth will suffice, although the recovery of native vegetation will be slower. [ABSTRACT FROM AUTHOR]

Background There are a variety of ways of increasing crop diversity to increase agricultural sustainability and in turn having a positive influence on nearby natural ecosystems. Competitive crops may provide potent management tools against invasive plants. To elucidate the competitive mechanisms between a sweet potato crop (Ipomoea batatas) and an invasive plant, mile-aminute (Mikania micrantha), field experiments were carried out in Longchuan County of Yunnan Province, Southwest China, utilizing a de Wit replacement series. The trial incorporated seven ratios of sweet potato and mile-a-minute plants in 25 m2 plots. Results In monoculture, the total biomass, biomass of adventitious root, leafstalk length, and leaf area of sweet potato were all higher than those of mile-a-minute, and in mixed culture the plant height, branch, leaf, stem node, adventitious root, flowering and biomass of mile-a-minute were suppressed significantly (P < 0.05). The relative yield (RY) of mile-a-minute and sweet potato was less than 1.0 in mixed culture, indicating that intraspecific competition was less than interspecific competition. The competitive balance index of sweet potato demonstrated a higher competitive ability than mile-a-minute. Except pH, other soil nutrient contents of initial soil (CK) were significantly higher than those of seven treatments. The concentrations of soil organic matter, total N, total K, available N, available P, available K, exchange Ca, exchange Mg, available Mn, and available B were significantly greater (P < 0.05) in mile-aminute monoculture soil than in sweet potato monoculture soil, and were reduced by the competition of sweet potato in the mixture. Conclusions Evidently sweet potato has a competitive advantage in terms of plant growth characteristics and greater absorption of soil nutrients. Thus, planting sweet potato is a promising technique for reducing infestations of mile-a-minute, providing weed management benefits and economic returns from harvest of sweet potatoes. This study also shows the potential value of replacement control methods which may apply to other crop-weed systems or invaded natural ecosystems. [ABSTRACT FROM AUTHOR]

The article explores an innovative research on the Russian olive fruit production situated in shelterbelt and riparian areas in Montana. Topics discussed include the preventive planning on invasive riparian populations and different demographic characteristics for shelterbelt organisms. Other topics include the environmental impacts of high cost of mechanical removal and biological control for the spread of Russian olive.

The article explores the innovative restoration in ecological area which were occupied by spotted knapweed, a non-native perennial forb in North America. Topics discussed include use of herbicide treatments, long term restoration for knapweed and establishing a study on the development of native warm-season grasses in Michigan. Other topics include the use of single annual mowing methods and experimental management strategies to prevent knapweed.

The article presents a study which was focused on identifying plant species that are prone to become invasive in California because of the horticultural trade. More than 774 species has been invasive in the Mediterranean climates out of which 186 species are expected to become invasive in California. It further mentions that 47 percent plant species are not naturalized in California.

The article discusses the study to control of the invasive noxious weed Canada Thistle by introducing native forbs to help improve grassland value, sustainable conservation land management, and restoration in the U.S. It says that native forbs of similar functional traits were planted at high seed density to increase competitive exclusion probability. It adds that the study used global positioning system (GPS), and geographic information systems (GIS) software.

Results of studies conducted in the Institute of Animal Science of the Republic of Cuba with an integral and multidisciplinary approach are presented. The topic developed is related with the applied strategies to control the degradation of grasslands invaded by wire grass (Sporobolus indicus). Other researches conducted with this weed in different tropical and subtropical regions considering the biological characteristics of this species are also considered. Reproduction methods of wiregrass and of seeds production are also dealt with. The negative effect of this weed on the economy and biomass production of an improved grassland is analyzed. The infestation level of wiregrass and the pureness percentage of the improved pasture are considered, as well as the application of recovery alternatives throughout new sowings or rehabilitation. It is proved that planting species of the Pennisetum genus by the plowing method or the traditional method are effective ways of control that also favor the recovery of completely damaged grasslands. The recovery or rehabilitation with the use of plowing plus harrowing, in combination with the chemical and organic fertilization, is a promising alternative to recover the energy of the grassland and an option to minimize the population of this weed and reestablish the productivity of the agroecosystem. A good animal and agrotechnical management is suggested after these labours, in order to achieve the sustainability of the improved pastures. The knowledge described will make possible to design a program for the integral control of the weed and the recovery of improved grasslands ecosystems invaded by wiregrass. [ABSTRACT FROM AUTHOR]

The article discusses positive and negative aspects of various plant species that are expanding throughout the Mediterranean region as of July 2011 due to the expansion of urbanization with an extension of gardens and planting areas. Topics discussed include formation of a protocol, based on relevant information, that determines which plant species should be cultivated and which should be prevented, human health risks linked with invasive plants, and bibliographic database on plant species.

The article presents measures to prevent and manage plant invasions on oceanic islands around the world. Topics discussed include roles of botanical garden leaders in educating people about invasive plants and formulating policies to prevent them, the use of native plants in restoring native biodiversity, and how partnerships with stakeholders help to manage invasive species. The St. Louis Codes of Conduct for managing invasive species is mentioned.

The article discusses responsibilities of botanic gardens in preventing the spread of alien invasive plant species through the cultivation of exotic plants in the gardens as of July 2011, with particular reference to the National Botanic Garden of Belgium (NBGB) and other northern European gardens. Topics discussed include reasons responsible for exotic plant invasions, role of hybridization in the evolution of invasive plants. Also mentioned are some invasive species such as Ebenaceae.