Chemometrically-aided general approach to novel adsorbents studies: Case study on the adsorption of pharmaceuticals by the carbonized Ailanthus altissima leaves.

A chemometrically based approach was applied to select the most efficient drug adsorbent among the biochars obtained from the novel feedstock, the leaves of the invasive plant (Ailanthus altissima). The representative target adsorbates (atenolol, paracetamol, ketorolac and tetracycline) were selected on the basis of their physicochemical properties to cover a wide chemical space, which is the usual analytical challenge. Their adsorption was investigated using design of experiments as a comprehensive approach to optimise the performance of the adsorption system, rationalise the procedure and overcome common drawbacks. Among the response surface designs, the central composite design was selected as it allows the identification of important experimental factors (solid-to-liquid ratio, pH, ionic strength) and their interactions, and allows the selection of optimal experimental conditions to maximise adsorption performance. The biochars were prepared by pyrolysis at 500 °C and 800 °C (BC-500 and BC-800) and the ZnCl2-activated biochars were prepared at 650 °C and 800 °C (AcBC-650 and AcBC-800). The FTIR spectra revealed that increasing the pyrolysis temperature without activator decreases the intensity of all bands, while activation preserves functional groups, as evidenced by the spectra of AcBC-650 and AcBC-800. High temperatures during activation promoted the development of an efficient surface area, with the maximum observed for AcBC-800 reaching 347 m2 g-1. AcBC-800 was found to be the most efficient adsorbent with removal efficiencies of 34.1, 51.3, 55.9 and 38.2 % for atenolol, paracetamol, ketorolac and tetracycline, respectively. The models describing the relationship between the removal efficiency of AcBC-800 and the experimental factors studied, showed satisfactory predictive ability (predicted R2 > 0.8) and no significant lack-of-fit was observed. The results obtained, including the mathematical models, the properties of the adsorbates and the adsorbents, clearly indicate that the adsorption mechanisms of activated biochars are mainly based on hydrophobic interactions, pore filling and hydrogen bonding.

Role of plant functional traits in the invasion success: analysis of nine species of Asteraceae.

Various attributes are hypothesized to facilitate the dominance of an invasive species in non-native geographical and ecological regimes. To explore the characteristic invasive attributes of the family Asteraceae, a comparative study was conducted among nine species of this family, co-occurring in the western Himalayan region. Based on their nativity and invasion status, the species were categorized as "Invasive", "Naturalized", and "Native". Fifteen plant functional traits, strongly linked with invasion, were examined in the test species. The analyses revealed a strong dissimilarity between all the plant functional traits (except leaf carbon [Leaf C]) represented by "Invasive" and "Native" categories and most of the traits (except leaf area [LA], leaf nitrogen [Leaf N], Leaf C, and leaf carbon-nitrogen ratio [C: N]) represented by the "Naturalized" and "Native" categories. Similarly, "Invasive" and "Naturalized" categories also varied significantly for most of the traits (except Leaf N, Leaf C, capitula per m² population [Cm²], seeds per capitula [Scapitula], and seed mass). Invasive species are characterized by high LA, specific leaf area [SLA] and germination, and low C:N and leaf construction costs [LCC]. Most of the traits represented by native species justify their non-invasive behavior; whereas the naturalized species, despite having better size metrics (plant height), resource investment strategy (aboveground non-reproductive biomass [BNR], and aboveground reproductive biomass [BR]), and reproductive output (capitula per individual plant [Cplant], and seeds per individual plant [Splant]) failed to invade, which implies that the role of these functional aspects in imparting invasion potential to a species is not consistent in all the ecosystems and/or phylogenetic groups. Results of PCA revealed that trait divergence plays a more imperative role in invasion success than naturalization in the species of the family Asteraceae. The present study is intended to refine the pre-generalized invasion concepts associated with family Asteraceae to ensure more accurate identification of the potential invaders and better management of the existing ones.

Phytoremediation as a viable ecological and socioeconomic management strategy.

Phytoremediation is an environmentally friendly alternative to traditional remediation technologies, notably for soil restoration and agricultural sustainability. This strategy makes use of marginal areas, incorporates biofortification processes, and expands crop alternatives. The ecological and economic benefits of phytoremediation are highlighted in this review. Native plant species provide cost-effective advantages and lower risks, while using invasive species to purify pollutants might be a potential solution to the dilemma of not removing them from the new habitat. Thus, strict management measures should be used to prevent the overgrowth of invasive species. The superior advantages of phytoremediation, including psychological and social improvements, make it a powerful tool for both successful cleanup and community well-being. Its ability to generate renewable biomass and adapt to a variety of uses strengthens its position in developing the bio-based economy. However, phytoremediation faces severe difficulties such as complex site circumstances and stakeholder doubts. Overcoming these challenges necessitates a comprehensive approach that balances economic viability, environmental protection, and community welfare. Incorporating regulatory standards such as ASTM and ISO demonstrates a commitment to long-term environmental sustainability, while also providing advice for unique nation-specific requirements. Finally, phytoremediation may contribute to a pleasant coexistence of human activity and the environment by navigating hurdles and embracing innovation.

Heracleum sosnowskyi pyrolysis - Energy and environmental aspects of biochar utilization.

The Heracleum sosnowskyi is a highly invasive plant species known for its rapid spread and the significant threat it poses to the ecosystem and human health, primarily due to its furanocoumarin content. In the present study, for the first time the pyrolysis process (200-600 °C) of Heracleum was conducted, demonstrating its efficacy in utilizing the material as feedstock and generating valuable solid by-products. It was found that biochar produced at temperatures of 200-300 °C is suitable for solid fuel production (HHV 20.2-24.1 MJ·kg-1) and has strong hydrophobic properties, while pyrolysis over 400 °C promotes the improvement of fertilizing properties by increasing the content of micro and macronutrients (K=112.4 g·kg-1 at 600 °C). The mass and energy analysis proved that in specific conditions (for dry > 300 °C; for wet > 400 °C), pyrolysis can be an effective way for Heracleum biomass conversion into valuable biochar without the need for external energy.

Active defense strategies for invasive plants may alter the distribution pattern of pests in the invaded area.

Introduction: In the invaded areas, it is believed that invasive species reduce their investment in defense due to the absence of natural enemies. Methods: By field investigation and a series of laboratory assays, This study explored the defense strategies of invasive plants. Results: Field investigation indicated that invasive plants have a antifeedant effect on herbivorous pests, and the distribution frequency of wormholes of native plants shows a peak at a distance of 2-3 m from the invasive species. The feeding preference experiment conducted with two generalist herbivorous insects (native insect Spodoptera litura and invasive insect Spodoptera frugiperda) showed that the invasive plants have a stronger antifeedant effect than native plants. By analyzing the content of secondary metabolites in the leaves of three invasive plants (Sphagneticola trilobata, Mikania micrantha, Ipomoea cairica) and three native plants (Ipomoea nil, Paederia foetida, Polygonum chinense), the leaves of invasive plants had higher concentrations of substances associated with defenses, including total phenols, flavonoids, jasmonic acid, tannin, H2O2, and total antioxidant capacity (TAC), and lower soluble protein concentrations than native plants. After leaf damage, compared to native plants, the leaves of invasive plants showed an overall increase in substances associated with defense, except for soluble sugar. Discussion: These results suggest that invasive plants maintain active defense strategies in invaded areas, leading to changes in the distribution patterns of herbivorous insects in a manner that facilitates invasion.

High-speed camera system for efficient monitoring of invasive plant species along roadways.

Invasive plant species pose ecological threats to native ecosystems, particularly in areas adjacent to roadways, considering that roadways represent lengthy corridors through which invasive species can propagate. Traditional manual survey methods for monitoring invasive plants are labor-intensive and limited in coverage. This paper introduces a high-speed camera system, named CamAlien, designed to be mounted on vehicles for efficient invasive plant species monitoring along roadways. The camera system captures high-quality images at rapid intervals, to monitor the full roadside when following traffic speed. The system utilizes a global shutter sensor to reduce distortion and geotagging for precise localistion. The camera system makes it possible to collect extensive data sets, which can be used for a digital library of the invasive species and their locations, but also subsequent training of machine learning algorithms for automated species recognition.

Responses of non-native and native plant species to fluctuations of water availability in a greenhouse experiment.

Water availability strongly influences the survival, growth, and reproduction of most terrestrial plant species. Experimental evidence has well documented the effect of changes in total amount of water availability on non-native vs. native plants. However, little is known about how fluctuations in water availability affect these two groups, although more extreme fluctuations in water availability increasingly occur with prolonged drought and extreme precipitation events. Here, we grew seven non-native and seven native plant species individually in the greenhouse. Then, we exposed them to four watering treatments, each treatment with the same total amount of water, but with different divisions: W1 (added water 16 times with 125 mL per time), W2 (8 times, 250 mL per time), W3 (4 times, 500 mL per time), and W4 (2 times, 1000 mL per time). We found that both non-native and native plants produced the most biomass under medium frequency/magnitude watering treatments (W2 and W3). Interestingly, non-native plants produced 34% more biomass with the infrequent, substantial watering treatment (W4) than with frequent, minor watering treatment (W1), whereas native plants showed opposite patterns, producing 26% more biomass with W1 than with W4. Differences in the ratio of root to shoot under few/large and many/small watering treatments of non-native vs. native species probably contributed to their different responses in biomass production. Our results advance the current understanding of the effect of water availability on non-native plants, which are affected not only by changes in amount of water availability but also by fluctuations in water availability. Furthermore, our results indicate that an increased few/large precipitation pattern expected under climate change conditions might further promote non-native plant invasions. Future field experiments with multiple phylogenetically controlled pairs of non-native and native species will be required to enhance our understanding of how water availability fluctuations impact on non-native invasions.

DNA barcoding of terrestrial invasive plant species in Southwest Michigan.

Because of the detrimental effects of terrestrial invasive plant species (TIPS) on native species, ecosystems, public health, and the economy, many countries have been actively looking for strategies to prevent the introduction and minimize the spread of TIPS. Fast and accurate detection of TIPS is essential to achieving these goals. Conventionally, invasive species monitoring has relied on morphological attributes. Recently, DNA-based species identification (i.e., DNA barcoding) has become more attractive. To investigate whether DNA barcoding can aid in the detection and management of TIPS, we visited multiple nature areas in Southwest Michigan and collected a small piece of leaf tissue from 91 representative terrestrial plant species, most of which are invasive. We extracted DNA from the leaf samples, amplified four genomic loci (ITS, rbcL, matK, and trnH-psbA) with PCR, and then purified and sequenced the PCR products. After careful examination of the sequencing data, we were able to identify reliable DNA barcode regions for most species and had an average PCR-and-sequencing success rate of 87.9%. We found that the species discrimination rate of a DNA barcode region is inversely related to the ease of PCR amplification and sequencing. Compared with rbcL and matK, ITS and trnH-psbA have better species discrimination rates (80.6% and 63.2%, respectively). When ITS and trnH-psbA are simultaneously used, the species discrimination rate increases to 97.1%. The high species/genus/family discrimination rates of DNA barcoding indicate that DNA barcoding can be successfully employed in TIPS identification. Further increases in the number of DNA barcode regions show little or no additional increases in the species discrimination rate, suggesting that dual-barcode approaches (e.g., ITS + trnH-psbA) might be the efficient and cost-effective method in DNA-based TIPS identification. Close inspection of nucleotide sequences at the four DNA barcode regions among related species demonstrates that DNA barcoding is especially useful in identifying TIPS that are morphologically similar to other species.

Response of Tahitian Bridal Veil (Gibasis pellucida) and Small-Leaf Spiderwort (Tradescantia fluminensis) to Postemergence Herbicides under Greenhouse Conditions.

Tahitian bridal veil (Gibasis pellucida) and small-leaf spiderwort (Tradescantia fluminensis) are both invasive species in natural areas throughout Florida. However, very little is known regarding herbicide control. To provide land managers with herbicidal control options for both species, postemergence herbicides were evaluated for efficacy in a greenhouse to identify herbicide options that control both species under similar settings. Four herbicides, including triclopyr acid, triclopyr amine + 2,4-D amine, triclopyr amine, and glufosinate were applied at standard label rates and compared to a non-treated control group for efficacy. Visual control ratings were taken at 2, 4, and 8 weeks after treatment (WAT), and shoot dry weights (WAT 8) and regrowth dry weights (WAT 12) were determined. Triclopyr (acid and amine) generally provided the most consistent control of both species as evidenced by the visual control ratings and shoot dry weight data which showed reductions of 76% to 89% in shoot biomass at trial conclusion. Triclopyr + 2,4-D reduced shoot dry weights by 52% to 54% and was the least effective when considering the control of both species.

Green synthesis of gold nanoparticles from the aqueous extracts of Sphagneticola trilobata (L.) J.F Pruski as anti-breast cancer agents.

The invasive plant, Sphagneticola trilobata (L.) J. F. Pruski, has been known for its bioactivities and used to synthesize gold nanoparticles (AuNPs). Nonetheless, previous research has not directly compared the effectiveness of the plant parts in producing the AuNPs. The objective of this study was to compare the effectiveness of the flower and leaf of S. trilobata in synthesizing AuNPs. S. trilobata leaves and flowers were separately extracted using distilled water at 60°C for 30 min. The leaf and flower extracts were mixed with the HAuCl. 3H2O and heated to 60°C for 30 min to yield AuNPs-ALSt and AuNPs-AFSt, respectively. AuNPs were also prepared using trisodium citrate (Na3C6H5O7) as a control. The resultant AuNPs were characterized using an ultraviolet-visible spectrophotometer, particle size analyzer, and scanning electron microscope. Antioxidant activity was evaluated based on 1-diphenyl-2-picrylhydrazyl (DPPH) inhibition and anticancer activity- 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide assay against MCF-7 cells. The AuNPs-ALSt and AuNPs-AFSt were revealed to have better stability and smaller particle diameters. AuNPs-ALSt and AuNPs-AFSt had average particle diameters of 11.86 ± 3.37 and 34.86 ± 23.56 nm, respectively. Agglomeration was predominantly observed in AuNPs synthesized using the flower or leaf extract as stipulated to be affected by the insufficient capping agent and intense hydrolytic reaction. AuNPs-AFSt had higher DPPH antioxidant activity than AuNPs-ALSt with half-maximal inhibitory concentrations of IC50 123.44 and 168.83 ppm, respectively. Both AuNPs-ALSt and AuNPs-AFSt could inhibit 80% growth of the MCF-7; however, at lower concentrations, inhibitory effects were more pronounced in AuNPs-AFSt. Aqueous extracts of S. trilobata flowers and leaves could be used to synthesize AuNPs, whereas the former yielded AuNPs with higher biological activities.

Alien plant species distribution in Romania: a nationwide survey following the implementation of the EU Regulation on Invasive Alien Species.

Background: Biological invasions pose an increasing risk to nature, social security and the economy, being ranked amongst the top five threats to biodiversity. Managing alien and invasive species is a priority for the European Union, as outlined in the EU Biodiversity Strategy for 2030 and the Kunming-Montreal Global Biodiversity Framework. Alien plant species are acknowledged to impact the economy and biodiversity; thus, analysing the distribution of such species provides valuable inputs for the management and decision-making processes. The database presented in the current study is the first consolidated checklist of alien plant species that are present in Romania, both of European Union concern and of national interest. This database complements a prior published distribution, based only on records from literature, bringing new information regarding the occurrence of alien plants in Romania, as revealed by a nationwide field survey. We consider this database a valuable instrument for managing biological invasions at both national and regional levels, as it can be utilised in further research studies and in drafting management and action plans, assisting stakeholders in making informed decisions and implementing management actions. New information: We present the results of the first nationwide survey of alien plant species in Romania, conducted between 2019 and 2022, in the framework of a national project coordinated by the Ministry of Environment, Waters and Forests and the University of Bucharest. The present database complements and updates the database published by Sirbu et. al (2022), which included occurrence records published until 2019. The new database includes 98323 occurrence records for 396 alien plant species in 77 families, with most species belonging to the Asteraceae family. One alien plant species in our database, the black locust Robiniapseudoacacia L., had more than 10,000 occurrence records. The distribution database also includes information on newly-reported invasive alien plant species of European Union concern in Romania (i.e. the floating primrose-willow Ludwigiapeploides (Kunth) P.H.Raven) and documents the presence of plants in 44 additional families compared to Sirbu et al. (2022). Each entry includes information on species taxonomy, location, year, person who recorded and identified the alien plant, geographical coordinates and taxon rank.

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Harm from alien invasive plants is increasing in Jingzhou County, Hunan Province. Based on a one-year field investigation and available literature, we investigated species composition, origin, flora, degree of harm and distribution pattern of invasive plants in the county. The results showed that there were 34 invasive plant species from 27 genera and 16 families in this County. The dominant invasive species belonged to Asteraceae (8 species) and Amaranthaceae (6 species), which accounted for 23.5% and 17.7%, respectively. The majority of invasive plants originated from South America (45.7%) and North America (30.4%). Tropical flora showed a significantly higher representation than temperate flora, signifying robust tropical characteristics amongst the invasive plant population. Based on hazard level classification, we recognized four types as malicious invasion (Level 1): Alternanthera philoxeroides, Erigeron annuus, E. canadensis, and Xanthium chinense. In addition, five types were classified as severe invasion (Level 2), eight types as local invasion (Level 3), fifteen types as general invasion (Level 4), while two types were still under observation (Level 5). The pattern of distribution demonstrated that invasive plants in Jingzhou County mostly spread along the verges of transportation roads, in human settlements, and in a few areas of water flow. The higher levels of invasion damage were principally concentrated in the central part of Jingzhou County.

Photosynthetic response dynamics in the invasive species Tithonia diversifolia and two co-occurring native shrub species under fluctuating light conditions.

To determine the invasiveness of invasive plants, many studies have compared photosynthetic traits or strategies between invasive and native species. However, few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations. We compared photosynthetic induction, relaxation dynamics and leaf traits between the invasive species, Tithonia diversifolia and two native species, Clerodendrum bungei and Blumea balsamifera, in full-sun and shady habitats. The photosynthetic dynamics and leaf traits differed among species. T. diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats. Thus, the slow induction response may be attributed to the longer stomatal length in T. diversifolia. Habitat had a significant effect on photosynthetic dynamics in T. diversifolia and B. balsamifera but not in C. bungei. In shady habitat, T. diversifolia had a faster photosynthetic induction response than in full-sun habitat, leading to a higher average stomatal conductance during photosynthetic induction in T. diversifolia than in the two native species. In contrast, B. balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat, resulting in higher carbon gain during photosynthetic relaxation. Nevertheless, in both habitats, T. diversifolia had an overall higher carbon gain during light fluctuations than the two native species. Our results indicated that T. diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain, which may contribute to its successful invasion.

An improved algorithm based on YOLOv5 for detecting Ambrosia trifida in UAV images.

A YOLOv5-based YOLOv5-KE unmanned aerial vehicle (UAV) image detection algorithm is proposed to address the low detection accuracy caused by the small size, high density, and overlapping leaves of Ambrosia trifida targets in UAV images. The YOLOv5-KE algorithm builds upon the YOLOv5 algorithm by adding a micro-scale detection layer, adjusting the hierarchical detection settings based on k-Means for Anchor Box, improving the loss function of CIoU, reselecting and improving the detection box fusion algorithm. Comparative validation experiments of the YOLOv5-KE algorithm for Ambrosia trifida recognition were conducted using a self-built dataset. The experimental results show that the best detection accuracy of Ambrosia trifida in UAV images is 93.9%, which is 15.2% higher than the original YOLOv5. Furthermore, this algorithm also outperforms other existing object detection algorithms such as YOLOv7, DC-YOLOv8, YOLO-NAS, RT-DETR, Faster RCNN, SSD, and Retina Net. Therefore, YOLOv5-KE is a practical algorithm for detecting Ambrosia trifida under complex field conditions. This algorithm shows good potential in detecting weeds of small, high-density, and overlapping leafy targets in UAV images, it could provide technical reference for the detection of similar plants.

Does the Invasive Heracleum mantegazzianum Influence Other Species by Allelopathy?

Heracleum mantegazzianum is an invasive species in middle Europe. The mode of action of its invasiveness is still not known. Our study focuses on observation of potential allelopathic influence by the production and release of phytochemicals into its environment. Plant material was collected four times within one season (April, May, June, July 2019) at locality Lekárovce (eastern Slovakia) for comparison of differences in composition and potential allelopathy. Water extracts from collected samples were used for different biological assays. The total phenols and flavonoids were determined spectrophotometrically. The profile and content of phenolic components, including coumarins, were determined by two techniques of liquid chromatography along with in vitro evaluation of the free radical scavenging activity of extracts (DPPH, Hydroxyl, Superoxide, and FRAP). The changes in composition in extracts in different seasonal periods were evident as well as potential phytotoxic activity in some concentrations on specific model plants. The slight antioxidant activity was noted. The invasiveness of the current species could be supported by the excretion of its phytochemicals into its surroundings and by different modes of action influencing living organisms in its environment.

Chemical Basis for Determining the Allelopathic Potential of Invasive Plant Wall Barley (Hordeum murinum L. subsp. murinum).

The study investigated compounds present in the invasive grass Hordeum murinum L. subsp. murinum and tested the allelopathic potential of this plant against common meadow species Festuca rubra L. and Trifolium repens L. Gas chromatography-mass spectrometry (GC-MS) performed separately on the ears and stalks with leaves of wall barley revealed 32 compounds, including secondary metabolites, that may play an important role in allelopathy. Two compounds, N-butylbenzenesulfonamide (NBBS) and diphenylsulfone (DDS), were described for the first time for wall barley and the Poaceae family. The presence of 6,10,14-trimethylpentadecan-2-one (TMP) has also been documented. Aqueous extracts of H. murinum organs (ears and stalks with leaves) at concentrations of 2.5%, 5%, and 7.5% were used to evaluate its allelopathic potential. Compared to the control, all extracts inhibited germination and early growth stages of meadow species. The inhibitory effect was strongest at the highest concentration for both the underground and aboveground parts of the seedlings of the meadow species tested. Comparing the allelopathic effect, Trifolium repens proved to be more sensitive. In light of the results of the study, the removal of wall barley biomass appears to be important for the restoration of habitats where this species occurs due to its allelopathic potential.

Synthesis of magnetic MFe2O4 (M = Ni, Co, Zn, Fe) supported on porous carbons derived from Bidens pilosa weed and their adsorptive comparison of toxic dyes.

Bidens pilosa is classified as an invasive plant and has become a problematic weed to many agricultural crops. This species strongly germinates, grows and reproduces and competing for nutrients with local plants. To lessen the influence of Bidens pilosa, therefore, converting this harmful species into carbon materials as adsorbents in harm-to-wealth and valorization strategies is required. Here, we synthesized a series of magnetic composites based on MFe2O4 (M = Ni, Co, Zn, Fe) supported on porous carbon (MFOAC) derived from Bidens pilosa by a facile hydrothermal method. The Bidens pilosa carbon was initially activated by condensed H3PO4 to increase the surface chemistry. We observed that porous carbon loaded NiFe2O4 (NFOAC) reached the highest surface area (795.7 m2 g-1), followed by CoFe2O4/AC (449.1 m2 g-1), Fe3O4/AC (426.1 m2 g-1), ZnFe2O4/AC (409.5 m2 g-1). Morphological results showed nanoparticles were well-dispersed on the surface of carbon. RhB, MO, and MR dyes were used as adsorbate to test the adsorption by MFOAC. Effect of time (0-360 min), concentration (5-50 mg L-1), dosage (0.05-0.2 g L-1), and pH (3-9) on dyes adsorption onto MFOAC was investigated. It was found that NFOAC obtained the highest maximum adsorption capacity against dyes, RhB (107.96 mg g-1) < MO (148.05 mg g-1) < MR (153.1 mg g-1). Several mechanisms such as H bonding, π-π stacking, cation-π interaction, and electrostatic interaction were suggested. With sufficient stability and capacity, NFOAC can be used as potential adsorbent for real water treatment systems.

Spartina alterniflora invasion altered phosphorus retention and microbial phosphate solubilization of the Minjiang estuary wetland in southeastern China.

Spartina alterniflora invasion is considered a critical event affecting sediment phosphorus (P) availability and stock. However, P retention and microbial phosphate solubilization in the sediments invaded with or without S. alterniflora have not been fully investigated. In this study, a sequential fractionation method and high-throughput sequencing were used to analyze P transformation and the underlying microbial mechanisms in the sediments of no plant (NP) zone, transition (T) zone, and plant (P) zone. Results showed that except for organic phosphate (OP), total phosphate (TP), inorganic phosphate (IP), and available phosphate (AP) all followed a significant decrease trend from the NP site to the T site, and to the P site. The vertical decrease of TP, IP, and AP was also observed with an increase in soil depth. Among the six IP fractions, Fe-P, Oc-P, and Ca10-P were the predominant forms, while the presence of S. alterniflora resulted in an obvious P depletion except for Ca8-P and Al-P. Although S. alterniflora invasion did not significantly alter the alpha diversity of phosphate-solubilizing bacteria (PSB) harboring phoD gene, several PSB belonging to p_Proteobacteria, p_Planctomycetes, and p_Cyanobacteriota showed close correlations with P speciation and IP fractions. Further correlation analysis revealed that the reduced soil pH, soil TN and soil EC, and the increased soil TOC mediated by the invasion of S. alterniflora also significantly correlated to these PSB. Overall, this study elucidates the linkage between PSB and P speciation and provides new insights into understanding P retention and microbial P transformation in the coastal sediment invaded by S. alterniflora.

Impacts of Invasive Plants on Native Vegetation Communities in Wetland and Stream Mitigation.

We sampled vegetation communities across plant invasion gradients at multiple wetland and stream mitigation sites in the Coastal Plain and Piedmont physiographic provinces of Virginia, USA. Impacts of invasion were evaluated by tracking changes in species composition and native vegetation community properties along the abundance gradients of multiple plant invaders. We found that native species richness, diversity, and floristic quality were consistently highest at moderate levels of invasion (ca. 5-10% relative abundance of invader), regardless of the identity of the invasive species or the type of mitigation (wetland or stream). Likewise, native species composition was similar between uninvaded and moderately invaded areas, and only diminished when invaders were present at higher abundance values. Currently, low thresholds for invasive species performance standards (e.g., below 5% relative abundance of invader) compel mitigation managers to use non-selective control methods such as herbicides to reduce invasive plant cover. Our results suggest that this could cause indiscriminate mortality of desirable native species at much higher levels of richness, diversity, and floristic quality than previously thought. From our data, we recommend an invasive species performance standard of 10% relative invader(s) abundance on wetland and stream mitigation sites, in combination with vigilant invasive plant mapping strategies. Based on our results, this slightly higher standard would strike a balance between proactive management and unnecessary loss of plant community functions at the hands of compulsory invasive species management.

Spillover effects from invasive Acacia alter the plant-pollinator networks and seed production of native plants.

Invasive flowering plants can disrupt plant-pollinator networks. This is well documented where invasives occur amongst native plants; however, the potential for 'spillover' effects of invasives that form stands in adjacent habitats are less well understood. Here we quantify the impact of two invasive Australian species, Acacia saligna and Acacia longifolia, on the plant-pollinator networks in fynbos habitats in South Africa. We compared networks from replicate 1 ha plots of native vegetation (n = 21) that were subjected to three treatments: (1) at least 400 m from flowering Acacia; (2) adjacent to flowering Acacia, or (3) adjacent to flowering Acacia where all Acacia flowers were manually removed. We found that native flowers adjacent to stands of flowering Acacia received significantly more insect visits, especially from beetles and Apis mellifera capensis, and that visitation was more generalized. We also recorded visitation to, and the seed set of, three native flowering species and found that two received more insect visits, but produced fewer seeds, when adjacent to flowering Acacia. Our research shows that 'spillover' effects of invasive Acacia can lead to significant changes in visitation and seed production of native co-flowering species in neighbouring habitats-a factor to be considered when managing invaded landscapes.