To effectively prioritize the management of invasive plants, it is necessary to reduce the risks posed by trade. This is particularly critical for the ornamental plant sector, which acts as a primary pathway for the introduction and distribution of non-native plant species. In this context, it is necessary to understand the perceptions of ornamental plant producers, who are the primary actors in the ornamental plant trade, about non-native plants, their impacts and risks. Using the Altınova district of Yalova province, Türkiye, we conducted a survey to explore the perceptions of 20 ornamental plant producers regarding non-native and invasive ornamental plant taxa. We also generated a list of ornamental plant taxa produced in the study area by using local sources referencing ornamental plants (such as producers’ catalogues). We found that of the 121 plants produced, 92 taxa were non-native, 23 were native and six were non-native hybrids, of which 31 taxa (11 taxa native and 20 taxa non-native to Türkiye) were found to be invasive elsewhere. Most of the plants produced were perennials (103 taxa). The vast majority of producers (70%) had heard the term “invasive plant” before. However, the concept of invasive plants is considered in the context of “plants other than for production purposes, i.e. weeds”. There is a lack of awareness among producers about the possible impacts caused by non-native taxa and their management status. We conclude that appropriate regulations should be made for the sale and use of non-native plants and awareness activities should be organized for all stakeholders and the public. Further research is required to identify, prioritize, and manage non-native ornamental plants and their potential impacts across all countries engaged in the ornamental plant trade to prevent future ornamental plant invasions.

Amur honeysuckle [Lonicera maackii (Rupr.) Herder] is an abundant invasive species throughout Kentucky and the surrounding region. It forms dense stands, outcompeting and displacing native species and adversely impacting the regeneration, succession, and biodiversity of deciduous forest communities. The objective of this study was to compare the efficacy of L. maackii removal alone relative to removal followed by restoration plantings to suppress reinvasion and facilitate forest understory native plant community recovery. In March 2019, a field experiment was conducted with the following treatments: (1) untreated control; (2) L. maackii removal with 0.023 kg ae L−1 glyphosate cut stump application (CH plots); and (3) same treatment as in 1, plus restoration plantings of wildrye grasses (Elymus spp.) and northern spicebush [Lindera benzoin (L.) Blume] (CHP plots). Lonicera maackii removal and cut stump glyphosate treatments effectively reduced L. maackii canopy cover, increased herbaceous cover, decreased bare ground, and increased species richness over time compared with untreated plots. However, we did not find any differences (P > 0.05) in L. maackii cover or other plant community variables between CH and CHP treatments over time. Thus, we found insufficient evidence that restoration plantings of Elymus spp. and L. benzoin suppressed L. maackii reinvasion compared with L. maackii removal alone. Spearman rank-correlation tests indicate L. maackii removal correlated with increased herbaceous cover (ρ = −0.75, P < 0.0001), lower bare ground (ρ = 0.714, P < 0.0001), and higher species richness (ρ = −0.693, P < 0.0001). Further studies of L. maackii removal plus restoration plantings are needed that test different species combinations and/or season of planting (i.e., spring vs. autumn) to determine the most effective restoration planting strategy to simultaneously suppress L. maackii reinvasion after removal and facilitate native plant community recovery in forest understories.

Neltuma juliflora (Sw.) Raf. (Fabaceae) is one of the most problematic invasive alien plant species in Ethiopia, posing serious threats to ecosystems and pastoral livelihoods. Despite its widespread invasion, limited evidence exists on how pastoral communities perceive its impacts, particularly in the Lower Omo Valley. In this study, we surveyed 154 households in Nyangatom District using semi-structured questionnaires and conducted four focus group discussions with communities in the Kibish cluster. Our findings indicate that 73.4% of households considered N. juliflora undesirable due to its suppression of grazing species, reduction of biodiversity, and restriction of livestock mobility. Pastoralists reported using several coping and control strategies, though most were limited to small-scale clearing around homesteads rather than broader rangeland management. Logistic regression analysis showed that education level, livestock ownership, and proximity to invaded areas significantly influenced perceptions of the invasion. Overall, N. juliflora has intensified socio-ecological vulnerability by degrading rangeland resources and affecting pastoral livelihoods. The results highlight the urgent need for feasible, locally adapted, and integrated management interventions.

Bracken fern (Pteridium aquilinum (L.) Kuhn) is an invasive species with significant ecological and economic impacts, making its detection and mapping critical for effective management. This study reviews remote sensing techniques for mapping P. aquilinum from 1996 to 2023. A total of 32 peer-reviewed articles were selected from Web of Science (WOS) and Scopus following the screening of 1,612 retrieved records. Bibliometric analysis, using VOSviewer software and Social Network Analysis (SNA), explored Keyword relationships, author collaborations, and institutional contributions. The research output shows fluctuations, publication gaps, and a resurgence in interest post 2021. Most studies (28%) were conducted in North America and Europe, with 26% originating from Africa. Key sensors identified include Landsat, Worldview-2, SPOT-5, and Unmanned Aerial Vehicles (UAVs). Recent advancements demonstrated the effectiveness of high-resolution optical sensors and machine-learning models in improving detection accuracy. However, challenges remain, including data limitations, methodological inconsistencies, and classification accuracy issues. This review emphasizes the need for higher-resolution imagery, advanced machine learning approaches, and standardized methodologies for improved P. aquilinum monitoring. Enhanced detection methods are crucial for effective ecological management, early intervention, and mitigating the spread of P. aquilinum.

Post-seeding vegetation management is critical for restoring grasslands dominated by invasive species, yet few studies have evaluated these strategies in the Aspen Parkland ecoregion. We tested the effects of no treatment (Control), mowing-only (Mow), herbicide-only (Herbicide; aminopyralid 52.5% + metsulfuron-methyl 9.45% at 230 g ai ha⁻¹), and mowing and herbicide application (Combination) on plant community composition, diversity, and biomass over two growing seasons following seeding of seven cool season native grass species. The study was conducted on a disturbed site in Edmonton, Alberta, Canada, where non-native Cirsium arvense, Sonchus arvensis, and Bromus inermis dominated prior to treatment. Treatments with aminopyralid+metsulfuron-methyl (aminopyralid+metsulfuron-methyl alone and Combination) significantly reduced noxious and introduced species richness and cover (p < 0.001), eliminated forbs, and shifted plant composition toward greater dominance by seeded and native grasses. However, these treatments also eliminated native shrubs (Rosa woodsia and Symphoricarpos occidentalis), reduced litter biomass, and increased bare ground. The Mow treatment maintained high species richness and forb biomass, with noxious and introduced species remaining dominant, and seeded species establishment improving slightly relative to the control. Despite differential species responses, overall seeded species richness, diversity, and cover did not differ significantly among treatments. Hesperostipa comata, Pascopyrum smithii, and Nassella viridula showed moderate establishment under treatments with aminopyralid + metsulfuron-methyl, while Festuca hallii, F. idahoensis, F. saximontana, and Koeleria macrantha established less in any treatment. Community composition diverged most between treatments with aminopyralid + metsulfuron-methyl and the control treatment. These results highlight trade-offs between invasive species control and impacts on non-target natives and ecosystem function. Among the treatments, aminopyralid + metsulfuron-methyl alone provided the most balanced outcome, suppressing invasive species while minimizing soil disturbance, and improving seeded grass recruitment. This study highlights the importance of integrating vegetation treatments with species-specific seeding when restoring heavily invaded grasslands in the Aspen Parkland.

Submerged aquatic vegetation (SAV) is often underdocumented at the species level in routine monitoring and regulatory assessments, where vegetation is commonly recorded without species-level identification. Here, we present a summary of existing records and field collections made in the Pennsylvania portion of Monongahela River system. Our findings suggest that the dominant SAV in this river is hydrilla [Hydrilla verticillata (L. f.) Royle], one of the most aggressive invasive macrophytes in North America. Further, our recent collections indicate the presence of other invasives: Eurasian watermilfoil (Myriophyllum spicatum L.) and curlyleaf pondweed (Potamogeton crispus L.). Native species such as coontail (Ceratophyllum demersum L.) and vallisneria (Vallisneria americana Michx.) were present but not prominent in sampled locations. The documentation of H. verticillata and other non-native invasive SAV species suggests that the Monongahela River is now hosting an invasive epidemic, one that may have widespread ecological implications.

Zornia latifolia Sm. (Fabaceae) is a perennial herb, known for reported psychoactive and medicinal properties, with a native range from Argentina to South Texas and some West Indian islands. There is disagreement on the status of Z. latifolia in Florida concerning whether it is a native species, an established non-native species, or a waif (i.e., a non-native species growing outside of cultivation, but not maintaining a viable population). In Florida, there is only one published record of Z. latifolia growing outside cultivation, in Hillsborough County, but multiple records of this species cultivated for research. I observed extensive populations of Z. latifolia in St. Lucie, Martin, Palm Beach, and Orange counties, and confirmed observations posted on-line from Hillsborough County. Based the recentness of its first record of growing outside cultivation in Florida (2015), its substantial persistent populations at multiple locations in peninsular Florida, and its occurrence primarily in and adjacent to mowed areas, Z. latifolia appears to be an established non-native species in the state. Whether it becomes a major invasive species in Florida remains to be seen.

Hydrilla [Hydrilla verticillata (L.F.) Royle] is a known, persistent aquatic weed in many lakes and reservoirs across the United States. Recently, focus has been placed on the management of invasions of H. verticillata into flowing systems due to increased difficulty in achieving effective control. In flowing environments, increased flow and water exchange rates commonly result in shorter herbicide exposure times using traditional application techniques. This research evaluated the concept of intermittent herbicide exposure as a potential management strategy to overcome operational challenges in high water exchange environments. Monoecious H. verticillata response to intermittent exposure to florpyrauxifen-benzyl, endothall, and fluridone at multiple concentrations and nontreatment intervals was evaluated in greenhouse-scale mesocosm experiments. Decreased efficacy was not observed when nontreatment intervals between exposures were introduced in florpyrauxifen-benzyl treatments. Monoecious H. verticillata treated with 30 µg ai L−1 florpyrauxifen-benzyl and a 6-d nontreatment interval resulted in 89% reduction in aboveground biomass. Nontreatment intervals did not influence endothall efficacy and biomass reduction increased with herbicide concentration (66% to 93%). Fluridone treatments at 5 µg L−1 resulted in 82% biomass reduction, while treatments at 10 and 15 µg L−1 resulted in 89% biomass reduction. Biomass reduction was slightly lower in fluridone applications with a 12-d nontreatment interval (83%) compared with other nontreatment intervals (85% to 91%). The high biomass reduction and similar response between treatments observed suggests the need for additional refinement and operational verification of intermittent herbicide exposures for monoecious H. verticillata control to increase cost-effectiveness and efficiency in public H. verticillata control programs.

Invasive, non-native plants frequently restructure ecosystems by homogenizing vegetation and altering trophic interactions, but the ecological consequences of invader removal are less predictable. Removal can redistribute light, nutrients, and detrital resources, initiating community reassembly that extends beyond vegetation recovery and may facilitate secondary invasions. We used a single-site invasive-removal field study to examine how management of European buckthorn (Rhamnus cathartica L.) reshaped vegetation structure, litter accumulation, and faunal communities in a postindustrial forest preserve in western New York State, USA. Across 18 plots representing managed, not-treated, and regrown R. cathartica conditions, we quantified herbaceous vegetation, leaf litter biomass, and the abundance of arthropods, pollinators and small mammals. Rhamnus cathartica removal was associated with a 10-fold increase in herbaceous plant cover and species richness, producing structurally complex understories and higher arthropod and pollinator abundance. However, managed plots also supported 3- to 5-fold higher densities of the invasive European fire ant (Myrmica rubra)—corresponding with increased leaf litter in managed plots. Ant abundance was positively associated with thicker, more persistent litter layers rather than canopy openness, and increasing M. rubra density, in turn, corresponded with reduced pollinator abundance. Detritivore and rodent responses were more closely linked to vegetation structure and litter conditions than to ant abundance.

The decline of native plant species associated with alien plant invasion is often assumed to be driven by competitive exclusion. However, invasive alien plant species could also directly or indirectly impact native plants by limiting reproductive success. Here, we tested whether invasive alien plants influence seed production, viability, and germination using the Benjoin [Terminalia bentzoe (L.) L.f. subsp. bentzoe], a critically endangered tree endemic to the Mascarene Islands (southwest Indian Ocean), as a model species. Seed production was estimated from seed densities under the canopy of adult individuals from one of the largest remaining subpopulations of the species (in Cirque de Mafate, Reunion Island). Seed viability was determined using a tetrazolium test on the different sets of seeds collected in the field. Densities of seeds and viable seeds were then tested for correlation with the percentage cover of invasive alien plant species in the liana, tree, shrub, and herbaceous forest layers. Seed germination was studied by sowing seeds in soils where three alien invasive plants, three endemics, and T. bentzoe subsp. bentzoe had previously been grown. Seed production and viability decreased with increasing abundance in invasive alien plants in the liana and tree strata but not in the lower vegetation strata. Mechanisms specific to tall-statured invasive alien plants could include competition for resources, interference with pollinator behavior and mechanical constraints. Seed germination was inhibited by the invasive alien succulent Mauritius hemp [Furcraea foetida (L.) Haw.] and T. bentzoe subsp. bentzoe itself, but enhanced by the endemic tree species Poupartia borbonica J.F.Gmel. These species may differ in their resource use intensity, associated microbial communities, and allelopathic effects. Our findings therefore suggest that plant invasions can significantly contribute to the decline of native plants through reduced reproductive ability and induce an extinction debt due to a lack of regeneration.

Many non-native invasive grass species increase wildfire activity and regenerate more quickly than native species. This invasive grass–fire cycle has severe negative consequences for ecosystems, creating a need to understand how different invasive grass species alter fuel characteristics and fire behavior, as well as effective treatments to control their abundance. To address these needs and increase fire and natural resource management preparedness, we performed a review and meta-analysis of recent (1985 to 2023) scientific literature. We focused on the Intermountain West, USA, where six dominant invasive grass species have already transformed ecosystems, including winter annuals—cheatgrass (Bromus tectorum L.), medusahead [Taeniatherum caput-medusae (L.) Nevski], red brome (Bromus rubens L.), and Mediterranean grass [Schismus arabicus Nees and Schismus barbatus (Loefl. ex L.) Thell]; and summer perennials—buffelgrass [Pennisetum ciliare (L.) Link] and Lehmann’s lovegrass (Eragrostis lehmanniana Nees). Within the 204 selected articles, B. tectorum was the most well-studied species, treatment effectiveness was the most common study type, and more studies addressed fuel accumulation than fire characteristics. While initial reductions in B. tectorum following wildfire were followed by large increases, P. ciliare initially increased and then steadily declined, and other invasive grass species had no significant post-fire changes over time. Chemical treatments were more effective than other treatments for B. tectorum, P. ciliare, and Schismus spp., although T. caput-medusae had a greater reduction with chemical treatments compared with the other species. In many cases, treatment effectiveness was enhanced when treatment types were combined or repeat treatments were conducted. Both B. tectorum and T. caput-medusae increased to pretreatment conditions within 3 and 5 yr, respectively, although there were no detectable trends for other species. Our results provide comprehensive comparisons of the effect of invasive grass species on fuel and fire characteristics and much needed insight on effective strategies for reducing invasive grass impacts to ecosystems.

Cogongrass [Imperata cylindrica (L.) P. Beauv.] is a recalcitrant invasive grass widespread in the southeastern United States. In non-crop systems, management relies on foliar applications of glyphosate and imazapyr; multiple applications over several years are often required, increasing labor, logistical, and chemical costs. Although numerous herbicide alternatives have been evaluated, few match the efficacy of glyphosate or imazapyr. Glufosinate is a broad-spectrum herbicide, and demand for glyphosate alternatives has generated interest in its potential for invasive grass management, but long-term evaluations of glufosinate and tank mixes for I. cylindrica are limited. This study evaluated single foliar spot applications of glufosinate (2.0 kg ae ha−1) alone and in tank mixtures with glyphosate (3.4 kg ae ha−1) or imazapyr (1.1 kg ae ha−1) at three Florida field sites heavily invaded (88% to 92% cover) by I. cylindrica using percent cover and belowground biomass. All treatments containing glufosinate produced rapid foliar necrosis, reducing cover to 15% to 21% within 14 days after treatment (DAT). By 270 DAT, cover increased in the glufosinate-alone (43%) and glufosinate + glyphosate (42%) treatments but remained approximately 25 to 30 percentage points lower than the control. At 540 DAT, cover in these treatments did not differ from that in the control. Across all sites, I. cylindrica cover at 540 DAT was reduced relative to the control by glyphosate (37%), imazapyr (9%), imazapyr + glufosinate (7%), and imazapyr + glyphosate (11%). Notably, the imazapyr + glufosinate mixture produced both rapid and sustained reductions in I. cylindrica cover. These results suggest glufosinate alone provides short-term suppression of aboveground tissue but can be enhanced through tank mixing with soil-active herbicides such as imazapyr to improve long-term suppression of belowground meristems.

Water hyacinth (Pontederia crassipes Mart.) is a free-floating aquatic plant native to South America that has spread to nearly 50 countries, becoming one of the world’s most invasive aquatic weeds. In Florida, the biocontrol agents Neochetina eichhorniae and Neochetina bruchi were released in 1970s, while Megamelus scutellaris was released in 2010. Assessing the impact of these biocontrol agents is crucial in evaluating efficacy, distribution, and overall progress in management efforts. The traditional survey and monitoring methods used to evaluate the impact of biocontrol present numerous challenges in data acquisition, especially in remote areas and aquatic habitats. This study aimed to detect damage caused by Neochetina spp. and M. scutellaris on P. crassipes using hyperspectral remote sensing. Plants were exposed to varying levels of Neochetina spp. and M. scutellaris herbivory for 2 and 4 wk under laboratory conditions. After the exposure period, the plants were scanned using a visible and near-infrared hyperspectral imaging system. Two classification algorithms, partial least-squares discriminant analysis (PLS-DA) and support vector machine (SVM) were employed for classification. SVM achieved high classification accuracy at both low and high damage levels, with overall training and validation accuracies of 84.9% and 78.79%, respectively, while PLS-DA only achieved high classification accuracy at high damage levels, with overall training and validation accuracies of 56.3% and 60.38%. Based on the observed performance metrics, both algorithms demonstrated improved classification accuracy as damage increased over time. The results indicated that hyperspectral remote sensing can be used to monitor and assess biocontrol agents damage on P. crassipes.

Tree of heaven [Ailanthus altissima (Mill.) Swingle] is an invasive tree that inhibits regeneration of forests. Management of forests invaded by A. altissima often includes chemically treating it and leaving dead boles behind. Verticillium wilt (Verticillium nonalfalfae) infects some populations of A. altissima, leading to localized mortality. Areas with population-wide A. altissima mortality may increase as this disease spreads or is used as a biocontrol agent. Ailanthus altissima has documented allelopathic compounds; stems left to decompose may result in soil legacy effects that negatively impact native plant restoration. The goal of this study was to determine whether soil under decomposing A. altissima wood has negative impacts on native perennial plant germination and growth. Ailanthus altissima was grown in a garden for 4 yr, basally cut, and treated with herbicide. The stems were sectioned and stacked into piles to decompose for 18 mo on grass and garden fabric, after which the wood was mulched. Soil from cores taken under each woodpile was added over potting media in pots in which seeds of three native perennials (purple coneflower [Echinacea purpurea (L.) Moench], dogbane (Apocynum cannabinum L.), and false nettle [Boehmeria cylindrica (L.) Sw.]) were planted. Seeds for half the pots were covered with potting media or mulch, respectively. The plants were grown under high- and low-light conditions in a greenhouse for 3 mo. Germinations were tallied, and dry shoot biomass was determined. Pots with woodpile soil had lower germination and biomass production for two of the native species, but mulch reduced the impact. Biomass was greater for all soil treatments with mulch added compared with treatments with no mulch. Plants growing in soil under garden fabric had germination values similar to plants in woodpile soil. This study reveals that soil under decomposing A. altissima wood is likely to negatively impact germination and growth of some newly seeded species for at least 18 mo.

Invasive plants negatively impact natural areas and impose huge costs associated with control and management. A new approach to significantly reduce these effects is to identify species in the earliest stages of spread, using data collected by public gardens across North America. Known as Public Gardens as Sentinels against Invasive Plants (PGSIP), this network includes multiple gardens, each contributing reports of these problematic species to a shared database using standardized guidelines. We examined this dataset to identify newly spreading species being noticed within gardens within different regions and determined whether they have been reported as state-listed/regulated/noxious outside gardens. As of November 2024, 53 PGSIP gardens in 28 U.S. states and Canadian provinces had submitted 996 reports, consisting of 597 unique species. The most commonly listed species were Amur corktree (Phellodendron amurense Rupr.), burning bush [Euonymus alatus (Thunb.) Siebold], and wintercreeper [Euonymus fortunei (Turcz.) Hand.-Maz.]. Other less frequently listed species included golden rain tree (Koelreuteria paniculata Laxm.), Norway maple (Acer platanoides L.), and castor aralia [Kalopanax septemlobus (Thunb.) Koidz.]. Of the 597 species, 36% were not listed by any state or province; gardens also had several species on watchlists, including Japanese tree lilac [Syringa reticulata (Blume) H. Hara] and Siberian squill (Scilla siberica Andrews). Our results demonstrate the utility of the approach and value of the database. This information can now inform the efforts of land managers, invasion biologists, the horticultural industry, and agencies tasked with invasive plant monitoring and assessment.

Callery pear (Pyrus calleryana Decne.) is a problematic woody invasive plant in eastern North America that invades old fields, forests, and disturbed sites. While management guidance typically suggests foliar, basal bark, cut stump, and hack-and-squirt applications of herbicides for P. calleryana, there is a dearth of studies focusing on the efficacy of specific treatments. We evaluated seven herbicide treatments for control of midstory P. calleryana. Cut stump and hack-and-squirt applications of glyphosate, imazapyr, and triclopyr and a soil application of hexazinone were repeated at six sites within Georgia, Kansas, and South Carolina, and all study trees were monitored for approximately 1 yr after herbicide application. Cut stump applications of glyphosate (478.73 g L-1), imazapyr (22.47 g L-1), and triclopyr (343.90 g L-1) provided the most consistent control with no resprouting and 100% mortality. Hack-and-squirt applications of glyphosate and triclopyr resulted in approximately 80% probability of mortality 1 yr after treatment, while hack-and-squirt application of imazapyr and soil application of hexazinone (287.58 g ai L-1) averaged only 20% and 25% probability of mortality, respectively. Our results demonstrate the efficacy of seven treatment options for P. calleryana control in three geographic locations with varied habitat types, and our data suggest that cut stump applications of glyphosate, imazapyr, or triclopyr or hack-and-squirt application of glyphosate or triclopyr may be useful for reducing populations of P. calleryana. that have grown past the sapling stage.

For many invasive plants, seed dormancy and persistence facilitate population expansion. These traits also complicate control efforts, as new seedlings may continue to emerge for years after the removal of existing plants. The maximum longevity of invasive plant seeds may range from years to decades. However, few seeds emerge after such a long time under field conditions. We conducted a field experiment testing the impact of seed burial depth on emergence of meadow knapweed (Centaurea × moncktonii C.E. Britton) and spotted knapweed [Centaurea stoebe L. ssp. micranthos (Gugler) Hayek] over 3 yr. For C. × moncktonii, emergence (raw data corrected for seed viability) was 57% at 0 cm, 28% at 2 cm, 3% at 4 cm, and 0% at 8 cm. For C. stoebe, emergence was 84% at 0 cm, 11% at 2 cm, 4% at 4 cm, and 0% at 8 cm. The primary flush of seedlings, averaged over Centaurea species and burial depths, occurred during the first few months of the study in fall 2018. Little emergence occurred after spring/summer 2019, although the study continued through spring/summer 2021. Our findings clarify the maximum burial depth from which these Centaurea species can emerge and demonstrate that emergence is concentrated in the first year after seed production.

Invasive M. spicatum sensu lato strains can differ in their growth, spread, impacts, and herbicide response. For example, strains of Eurasian (Myriophyllum spicatum L.) and hybrid (Myriophyllum spicatum × Myriophyllum sibiricum Kom.) watermilfoil have been characterized as resistant or susceptible to specific herbicides (e.g., fluridone and 2,4-D). Identifying resistant and susceptible strains can inform managers as to whether a specific herbicide should be used to treat a water body. However, to date, no centralized location existed to house and share M. spicatum and M. spicatum × M. sibiricum strain and herbicide response information. To address this need, we built MilfoilMapper, a publicly available, user-friendly R Shiny application that houses invasive M. spicatum sensu lato strain distribution and herbicide response information. To date, we have identified 290 strains from more than 300 lakes across the United States sent by state agencies, aquatic plant managers, and citizen scientists. Although some strains are found only in a single lake, some strains have been found in multiple lakes. Therefore, strain information obtained from either the field or the lab can be applied to additional lakes where these strains are found. We encourage people to incorporate genetic surveying and monitoring into their M. spicatum management plans to help identify strains that should be prioritized for herbicide characterization. We believe MilfoilMapper will facilitate and encourage these actions by providing a centralized, interactive platform for tracking M. spicatum and M. spicatum × M. sibiricum strain data, enabling lake managers, stakeholders, and state agencies to share experiences and resources to improve the efficacy and efficiency of invasive M. spicatum sensu lato management.

Sporobolus natalensis (Steud.) T. Durand & Schinz. and Sporobolus pyramidalis P. Beauv., generally known as giant rat’s tail grasses, are two significant weed species that invade summer fields and pastures in the eastern regions of Australia. This study was conducted to examine seed germination behavior, seedling emergence, and the response of these species to various herbicides. Seed germination and seedling emergence were assessed in response to environmental factors, including alternating temperature regimes (15/5, 20/10, 25/15, 30/20, and 35/25 C), light conditions (dark and light/dark), osmotic potentials (0, −0.1, −0.2, −0.4, −0.8, and −1.6 MPa), and seed burial depths (0, 0.5, 1, 2, and 4 cm). Furthermore, the efficacy of several post-emergence herbicides was evaluated in pots under outdoor environmental conditions. Germination was higher under light/dark (12-h light/12-h dark) conditions than under continuous darkness (24 h). The seeds of both species exhibited significantly higher germination (>95%) under 12-h light at higher temperatures (35/25 C) compared with low (20/10 C) or medium (25/15 C) temperatures. The osmotic potential required to inhibit 50% of maximum germination was −0.77 MPa for S. natalensis and −0.59 MPa for S. pyramidalis. Seedling emergence decreased with increasing burial depth, with no emergence observed from seeds buried at depths of 4 cm. Applying herbicides significantly reduced both species’ seedling survival and dry matter. The most effective herbicides for controlling spring-germinated S. pyramidalis and S. natalensis were haloxyfop, clethodim, butroxydim, glyphosate, glufosinate, and paraquat, which provided satisfactory control of both species. The findings from this study can be used to develop effective management strategies for controlling S. pyramidalis and S. natalensis in agricultural systems.

Weed Risk Assessments (WRAs) aim to distinguish potentially invasive plants from non-invasive plants using traits such as the likelihood that the species will be introduced, establish, spread, and/or have negative impacts and (sometimes) whether it can be managed effectively. International standards for the criteria used to assess risk have been proposed to improve the sharing and transferability of WRA results. However, it is unclear whether existing WRAs follow these standards. Here, we compiled a global database of national-level and subnational-level (state/province) WRAs and evaluated their assessment criteria relative to an amended list of proposed minimum standards. We searched for WRAs in 240 countries and retrieved 20 unique assessments associated with 81 countries. The most comprehensive WRA was the “Guidelines for the Generic Ecological Impact Assessment of Alien Species” created by Norway, which satisfied 23 of 24 standards. The International Plant Protection Convention (IPPC) Pest Risk Analysis Framework and the European and Mediterranean Plant Protection Organization (EPPO) Express Pest Risk Analysis were also comprehensive, fulfilling 21 of 24 standards. All national-level WRAs included a description of the focal species’ taxonomy, a description of risk assessment area, an assessment of the likelihood of spread of the focal species, and an assessment of the likelihood of impact of the focal species. Conversely, it was rare for WRAs to include a history of spread of the focal species or an evaluation of the possible effects of climate change. States/provinces showed a similar pattern (i.e., rarely discussed climate change), but also frequently lacked assessment of impact on ecosystem services and metrics of uncertainty. Many WRAs are shared between countries, but few are shared between states/provinces. Adopting similar WRA standards would allow policymakers and governing bodies to more effectively share information and results from completed WRAs, improving consistency of regulated plants across jurisdictional borders.