Invasive Plant Research Articles

Preliminary Identification and Quantification of Individual Polyphenols in Fallopia japonica Plants and Honey and Their Influence on Antimicrobial and Antibiofilm Activities.

Fallopia japonica (FJ), an invasive plant species known for its rich bioactive compounds, has been used for centuries in traditional Chinese medicine. Despite its significant beekeeping potential, this aspect of FJ remains underexplored. This research aims to investigate the antimicrobial and antibiofilm properties of FJ plants and honey. Notably, this study is the first to identify individual phenolic compounds in both FJ plant tissues and FJ honey, highlighting resveratrol as a marker of FJ honey. The study tested inhibitory activity against seven bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Salmonella enteritidis, and the yeast Candida albicans. Disk diffusion and microdilution methods were used to assess antimicrobial activity, while the crystal violet staining test evaluated antibiofilm activity. Results showed that FJ plant tissues and honey exhibited strong inhibition, particularly against Gram-negative bacterial strains. The most significant inhibition of biofilm formation, by both FJ plant tissues and honey, was observed against Staphylococcus aureus and Escherichia coli. A significant positive correlation was found between antimicrobial activity and individual polyphenols, especially resveratrol. The antibacterial and antibiofilm potential of FJ plant tissues and honey suggests promising applications in sustainable beekeeping. Further research is necessary to evaluate the bioactive compounds found in FJ honey and their health effects.

Ecosystem restoration coupled with poverty alleviation in eThekwini Municipality, KwaZulu‐Natal Province, South Africa

Ecosystem restoration is a necessity for addressing socio‐ecological challenges by improving ecosystem resilience and alleviating poverty through local community involvement. Here, we review a community‐based, large‐scale ecosystem restoration program, Working for Ecosystems, implemented by eThekwini Municipality in KwaZulu‐Natal, South Africa, between 2007 and 2022. For this study, we interrogated monthly and annual reports generated by the program between 2011 and 2021 to describe how the program worked to suppress invasive alien plants (IAPs) and provided employment opportunities to marginalized groups (women, youth, military veterans, and people living with disabilities). Annual budget was positively correlated with the area cleared of IAPs and effort (person‐days in the field). The program successfully incorporated marginalized groups, but military veterans and people living with disabilities remained in smaller numbers and were not well quantified. Participants were encouraged to constitute companies—Small, Medium, and Micro Enterprises—that were then subcontracted to the program or could progress to other endeavors, allowing other community members to enter the program. A steady increase in the implementation budget emphasized the need for a long‐term plan to ensure accountability and sustainability of restoration and socio‐ecological systems.

Ni-Doped Activated Carbon from Invasive Plants as a Potential Catalyst

In this study we synthesized and characterized Ni/AC (Activated Carbon) systems. AC was obtained through pyrolysis of golden rod’s dried biomass. Ni nanoparticles were deposited on AC’s surface using a wet impregnation method from a nickel nitrate solution. SEM, MP-AES and DSC-TGA techniques were used for surficial and structural characterization, while ash content was made to check mineral ingredients input. The DSC-TGA study revealed that all carbons show good thermal stability up to 900 °C, which is far above operating temperatures in the methanation process. For all three carbons the BET isotherms were made as well. They show that in most cases the carbon’s surface is well developed and can adsorb decent amounts of metal. MP-AES helped to evaluate the efficiency of the impregnation process, which reached 76 mg of Ni per 1 g of carbon. The SEM-EDS study showed good distribution of Ni nanoparticles across AC’s surface. We also made a comparison of our systems to similar materials from other works.

Application of deep neural network identification models based on garden environment perception in plant protection

Perception of garden environment plays a crucial role in the control of invasive plants. Timely and accurate detection of invasive plants can significantly enhance the effectiveness of their control measures. Neural network technology can effectively identify the presence of invasive plants in the environment so that effective measures can be taken to protect garden plants from invasive species. In this paper, we propose a deep bilinear transformed ResNeXt (DBT-ResNeXt) model that replaces ResNet with ResNeXt to construct a two-branch structure for invasive plant recognition. The model is trained and validated using a dataset constructed from publicly available images of invasive plants. Experimental results demonstrate that compared to various other models, DBT-ResNeXt exhibits superior performance, achieving a recognition accuracy of 94.66%.

Study on the biocontrol effect of Streptomyces sp. NEAU-KT41 and its cell-free culture filtrate against wheat root rot

Wheat root rot, caused by Bipolaris sorokiniana, is a significant and extensive soilborne disease. Streptomyces sp. NEAU-KT41 was isolated from healthy wheat root soil and possessed strong antifungal activity against B. sorokiniana. Findings from the pot test indicated that strain NEAU-KT41 (108 CFU/mL) and its 10 % cell-free culture filtrate had significant biocontrol efficiency against wheat root rot, with 66.67 % and 64.4 %, respectively, resulting in significant increases in biomass and chlorophyll content. For 108 CFU/mL spore suspension, the plant height increased by 167.52 %; root length by 141.64 %, fresh weight by 65 %, chlorophyll a by 13.43 %, and chlorophyll b by 51.02 % under disease stress. For the 10 % cell-free culture filtrate, the plant height increased by 21.93 %, root length by 17.92 %, dry weight by 29.35 %, chlorophyll a by 17.92 %, and chlorophyll b by 82.15 % under disease stress. Moreover, strain NEAU-KT41 could produce proteases, amylases, lipases, and ACC deaminase, and had the ability to decompose organic phosphorus and fix nitrogen. The cell-free culture filtrate affected B. sorokiniana in several manners, including increasing the cell membrane permeability, diminishing the soluble protein content in the mycelia, impeding conidia germination and germ tube extension, and affecting B. sorokiniana invasion of plants. Briefly, Streptomyces sp. NEAU-KT41 is a prospective biocontrol agent that can be used to manage root rot in wheat and has potential applications.

Monitoring and assessing the effectiveness of the biological control implemented to address the invasion of water hyacinth (Eichhornia crassipes) in Hartbeespoort Dam, South Africa

Water hyacinth is one of the most aggressive alien invasive plants, which invades freshwater resources and destroys native biodiversity. The plant proliferates rapidly over a short space of time, forming thick dense layer on the surface of freshwater bodies. Monitoring and management of water hyacinth is essential to protect water resources affected by the presence of this plant. The study assessed the effectiveness of biological agent (Megamelus scutellaris) applied in the Hartbeespoort Dam from pre (2016–2017) and post (2018–2023) biological control to manage water hyacinth spread and proliferation. In achieving this main goal, the study used advanced cloud-computing machine learning techniques and multi date Sentinel-2 Multispectral Instrument (MSI) data to monitor the effectiveness of such biological control. During this analysis, remote sensing data was acquired for two time periods namely: pre-intervention (2016–2017) and post intervention (2018–2023) to establish variation in the spatio-temporal distribution of water hyacinth in the Hartbeespoort Dam using various machine learning techniques (Support Vector Machine (SVM), Classification and Regression Tree (CART), Random Forest (RF) and Naïve Bayes (NB)) in Google Earth Engine cloud computing platform, and assessed the spectral separability of water hyacinth from numerous land cover types, within and around the Hartbeespoort Dam using the Sentinel-2 derived spectral reflectance curves. The results indicated that the extent of water hyacinth area coverage decreased from 15% to below 6% between the period of 2018 and 2021, however, a significant increase was noted between November 2022 and April 2023, after the biological control was introduced. The significant increase observed during the time period of November 2022 and April 2023 can be attributed to nutrient rich water discharging into the dam from the Crocodile River during the time of flooding reported in November 2022. The result further indicate that RF produced the highest overall accuracies ranging between 93.42% and 98.70%. While NB produced the lowest accuracies ranging between 87.76% and 92.08%. These findings underscore the relevance of new generation satellite dataset and machine learning algorithms in monitoring the effectiveness of the biological controls of alien invasive spread provide information regarding alien plant invasion. Therefore, aligning with Sustainable Development Goals (SDG 6) emphasizing on the importance of implementing effective control measures to control invasive species and their impact on water resources thus ensuring the sustainability of freshwater ecosystems and the availability of clean water resources.

Lindernia dubia (L.) Pennel as an Alien Weed in Central Spain: A Case Study.

Lindernia dubia (L.) Pennell is a species with invasive behavior outside of its native range of distribution (America), linked mainly to aquatic habitats. This annual species has been acknowledged as a weed in rice paddies in Europe and Asia. Due to the impacts of this invasive plant, some authors have even listed this species as a global invader. The present work focused on spontaneous plant species occurring in seedlings of Typha domingensis Pers. grown in central Spain for the establishment of constructed wetlands. Weed inventory revealed the presence of L. dubia as a dominant spontaneous species in this crop environment. A suite of mesocosm experiments were designed to study the population density of L. dubia versus that of the other dominant plant species, and to determine traits associated with its weedy potential. The results showed that L. dubia presents competitive attributes such as morphological variability, early flowering, long seeding time, short growth cycle, small and light seeds and a high seed production and germination rate (25 °C), meaning a high reproductive capacity in a cycle of about three months for plant growth in non-limiting conditions. The data obtained from this work provide a basis for understanding the weedy potential of L. dubia, and for management decisions of a potentially invasive species, which has been little investigated in Europe.

Arbuscular mycorrhizal communities respond to nutrient enrichment and plant invasion in phosphorus‐limited eucalypt woodlands

Abstract Arbuscular mycorrhizal fungi (AMF) facilitate ecosystem functioning through provision of plant hosts with phosphorus (P), especially where soil P is limiting. Changes in soil nutrient regimes are expected to impact AMF, but the direction of the impact may depend on context. We predicted that nitrogen (N)‐only enrichment promotes plant invasions and exacerbates their P limitation, increasing the utility of AMF and promoting AMF diversity. We expected that enrichment with N, P and other nutrients similarly promotes plant invasions, but decreases the benefit and diversity of AMF because P is readily available for both native and exotic plants. We tested these hypotheses in eucalypt woodlands of south‐western Australia, that occur on soils naturally low in P. We evaluated AMF communities within three modified ground‐layer states representing different types of nutrient enrichment and associated plant invasions. We compared these modified states to near‐natural reference woodlands. AMF richness varied across ground‐layer states. The moderately invaded/N‐enriched state showed the highest AMF richness, while the highly invaded/NP‐enriched state showed the lowest AMF richness. The reference state and the weakly invaded/enriched state were intermediate. AMF richness and colonisation were higher in roots of exotic than native plant species. AMF community composition differed among ground‐layer states, with the highly invaded/NP‐enriched state being most distinct. Distinctions among states were often driven by family‐level patterns. Reference and moderately invaded/N‐enriched states each supported distinct groups of zero‐radius operational taxonomic units (zOTUs) in Acaulosporaceae, Gigasporaceae and Glomeraceae, whereas Gigasporaceae and Glomeraceae were nearly absent from the highly invaded/NP‐enriched state. Further, Diversisporaceae and Glomeraceae were most diverse in the moderately invaded/N‐enriched state. Synthesis. Both the nature of soil nutrient enrichment and plant provenance matter for AMF. N‐only enrichment of low‐P soils increased AMF richness, likely due to the introduction of AMF‐dependent exotic plant species and exacerbation of their P limitation. In contrast, multi‐nutrient enrichment, decreased AMF richness potentially due to a decrease in host dependence on AMF, regardless of host provenance. The changes in AMF community composition with nutrient enrichment and plant invasion warrant further research into predicting the functional implications of these changes.

Divergence in spatial patterns of leaf stoichiometry between native and non-native plants across coastal wetlands

The spatial pattern of leaf stoichiometry is critical in predicting plant palatability and ecosystem productivity and nutrient cycling rates and thus is a major focus of community ecological research. Coastal wetlands as vital blue carbon ecosystems, with high possibility to be vulnerable to plant invasion, studies focused on stoichiometry and its pattern are important to unveil the elements cycling process. However, previous studies have mainly focused on stoichiometry in terrestrial ecosystems, there are few studies conducted on coastal wetland ecosystems, especially the studies that compare leaf stoichiometry between native and non-native plants in coastal wetlands. In this study, we compared the latitudinal patterns of leaf nutrient contents and their stoichiometric ratios between native and non-native plant species across coastal wetland ecosystems and investigated whether leaf stoichiometric patterns were driven by climatic factors. We used a compiled global data set of 954 records to conduct a systematic meta-analysis. The results showed that there were significant differences in latitudinal patterns of leaf carbon (C) and nitrogen (N) contents and C:N ratio between native and non-native species, as well as significant differences in leaf C, N, and phosphorus (P) contents. For native species, we found significant latitudinal patterns in leaf C, N, and P contents and C:N and C:P ratios, whereas for non-native species, we found significant latitudinal patterns in leaf N content and C:P and N:P ratios. Mean annual temperature of the data collection site was a significant predictor of leaf stoichiometry of native plants but only of leaf N content and C:P ratio of non-native plants. Thus, we demonstrated spatial heterogeneity in leaf stoichiometries between native and non-native plants in coastal wetlands, indicating that such differences should be emphasized in future biogeochemical models and plant-herbivore interaction studies owing to the important role of wetland plants in global C, N, and P cycles. Our findings increase understanding of plant-related nutrient and elements cycling in coastal wetlands, as well as improve predictions of plant growth rates and vegetation productivity across large scales under plant invasion scenarios.

Prioritizing management actions for invasive non-native plants through expert-based knowledge and species distribution models

Given the high number of non-native plants that are being introduced worldwide and the time required to process formal pest risk analyses, a framework for the prioritization of management actions is urgently required. We therefore propose a framework for a replicable and standardized prioritization for management actions (eradication, control and monitoring) of invasive non-native plants, combining expert knowledge, current and future climatic suitability estimated by species distribution models (SDMs), clustering and ordination techniques. Based on expert consultation and using Italy as case study, invasive non-native plant species were selected and three categories of management actions were identified: eradication, control and containment, and monitoring. Finally, two further classes of priorities were proposed for each of the management actions: “high” and “low” priority. Overall, SDMs highlighted a high and very high suitability for Continental and Mediterranean bioregions for most invasive plants. Cluster analysis revealed three distinct clusters with varying levels of suitability for the Italian bioregions. Cluster 1 exhibited a higher suitability across all Italian bioregions, whereas non-native plants grouped in Cluster 2 predominantly featured high suitability in Mediterranean areas. Finally, Cluster 3 showed the lowest suitability values. Two ordination analysis highlighted the variability in bioclimatic suitability for each non-native plant within each cluster, as well as their current distribution pattern. Lastly, a third ordination, integrating bioclimatic suitability and spatial patterns, has allowed the differentiation of management actions for each non-native plant at both national and bioregional scales. Specifically, seven non-native plants were earmarked for eradication action, six for monitoring action, while the remaining species were deemed suitable for control and containment. Our results and the methodology proposed meet the demand for replicable new early warning tools; that is to predict the location of new outbreaks, to establish priorities for eradication, control and containment, and to monitor invasive non-native species.

Functional mechanisms underlying the persistence of Opuntia ficus-indica in a Mediterranean-type ecosystem after fire

Changes in fire regime can favor invasive plants in Mediterranean-type ecosystems. The goal of this experiment was to understand the post-fire dynamics of the invasive cactus, Opuntia ficus-indica, by assessing the contribution and impact of clonal propagation and sexual reproduction on the recruitment of this species after fire. The number of O. ficus-indica new clones and seed-derived plants was estimated after a burn event in a natural area located in the western Mediterranean (Catalonia, NE Spain). Functional stress markers, relative growth rate, and contents of both growth- and stress-related phytohormones were measured. Furthermore, remaining plants damaged by fire were evaluated regarding fruit size, seed number, and viability, as well as other reproductive traits. Results showed that 95 % of the new recruits in the burned area were clones. Clones showed a higher water and chlorophyll content than seed-derived plants. The relative growth rate was consequently higher in clones than in seed-derived plants, which was also associated with higher contents of growth-related hormones (cytokinins and gibberellins) in the former. Furthermore, seeds produced by burned plants exhibited a thicker funicular envelope compared to seeds from unburned plants. It is concluded that, although clonal propagation was the main reproductive strategy observed after fire, its combination with sexual reproduction and efficient physiological strategies of survival guarantees persistence of this invasive plant species in burned areas due to an effective and fast recovery in cactus cover in the short term while contributing to the genetic variability in the population in the long term.

Clonal integration facilitates the expansion of Hydrocotyle vulgaris from a limited space to a larger area

AbstractClonal integration is an important ecological advantage of clonal plants. To ask whether clonal integration can help invasive plants escape space limitations, we tested the hypothesis that it can promote the growth of apical ramets when their connected basal ramets grow in limited space. We conducted a greenhouse experiment on the common perennial herb Hydrocotyle vulgaris. Clonal fragments consisting of pairs of connected ramets grew with basal ramets in three different sizes of pots (small, medium, and large) and apical ramets in large pots, and the connection between ramets was either severed or left intact. Pot size significantly affected the growth of basal ramets such that the biomass, number of leaves and flowers, and stolon length were in general greater in medium pots than in large and small pots when stolons were intact and were greater in medium and large pots than in small pots when stolons were severed. Furthermore, pot size interacted with severance to affect the performance of H. vulgaris. When the basal ramets grew in small pots, the intact stolon resulted in a significant promotion of apical ramet growth, but such positive effect was not found when the basal ramets grew in medium and large pots. Our results suggest that H. vulgaris is able to promote the growth of apical ramets to occupy the surrounding areas through clonal integration when the space where basal ramets grow is limited.

Mitigating invasive species using biochar derived from invasive plants in saline‐alkaline wetland plant communities dominated by Amaranthus palmeri

AbstractAimsEffective prevention and management of biological invasions are crucial. One promising approach involves introducing biochar to invaded plant communities to modify interspecific relationships among invasive and native plants, ultimately aiding in the suppression of invasive species. This study aimed to explore the effects of invasive‐plant biochar on an established invaded plant community.LocationTianjin coastal saline‐alkaline wetland, China (38°46′ N, 117°34′ E).MethodsInvaded plant communities were established using soils from an Amaranthus palmeri‐invaded wetland with an intact seed bank, incorporating invasive‐plant biochar derived from A. palmeri and Spartina alterniflora into the soil at 0%, 1%, 3%, and 5% addition rates (m/m). Plant above‐ground biomass, height, stem diameter, abundance, α/β‐diversity, niche breadth, and species co‐occurrence networks were analyzed.ResultsThe addition of invasive‐plant biochar significantly decreased the performance measures of the invaded plant community. The biochar addition rate had a more substantial impact on plant community structure than the type of biochar used. There was a decrease in the abundance of A. palmeri and an increase in native plants across most treatments, with S. alterniflora biochar exhibiting a more pronounced effect compared to A. palmeri biochar. Invasive‐plant biochar affected the niche breadth of A. palmeri and other dominant native species, particularly at higher addition rates, resulting in reduced niche overlap. At a 5% addition rate, A. palmeri and S. alterniflora biochar had contrasting effects on the complexity of interspecific relationships within the plant community. Phylogenetic β‐diversities were significantly correlated with the biochar addition rate and stochastic processes primarily governed plant community assembly across all treatments.ConclusionsOur findings underscore the potential of biochar derived from invasive plants to mitigate the impact of invasive species on saline‐alkaline wetland plant communities dominated by A. palmeri. This approach offers a promising avenue for managing biological invasions and restoring native plant species.

Gene expression controlling signalling molecules within mutualistic associations of an invasive plant: An evolutionary perspective

Abstract Chemical signals are crucial in mediating ecological and evolutionary adaptation of plants to their environments. Indeed, invasive plants may produce greater amounts of chemical metabolites in their new ranges. Some of these chemicals can enhance their mutualistic interactions and improve invasive plant performance, but genetic mechanisms of such adaptations are unexplored. We used Triadica sebifera plants as a model to investigate evolutionary changes in chemical signals that enhance arbuscular mycorrhizal (AM) fungal associations. Previous studies found that T. sebifera plants from invasive populations had higher root exudate concentrations of the flavonoid quercetin and elevated AM fungal colonization compared with those from native populations. Here, we explored genetic variation in strigolactone concentrations in root exudates and their contribution to AM fungal colonization with strigolactone analogue GR24 additions. In addition, we studied how gene expression patterns related to flavonoid and strigolactone biosynthesis varied among invasive and native populations using comparative genomics, transcriptomics and fluorescent real‐time quantitative PCR. We found that plants from invasive populations had higher concentrations of the strigolactone 5‐deoxystrigol in root exudates that were correlated with higher AM fungal colonization rates, relative to those from native populations. Exogenous applications of GR24, a synthetic analogue of 5‐deoxystrigol, increased AM fungal colonization. We found higher expression of a single gene in flavonoid (FLS) and strigolactone (DAD1) biosynthesis pathways increased levels of quercetin and 5‐deoxystrigol in plants from invasive populations, respectively. Synthesis. Understanding the role of genetic evolution in enhancing mutualisms of invasive plants provides new insights into the underlying mechanisms of plant invasion. This study suggests that an invasive plant enhanced its mutualisms by upregulating the expression of key genes related to secondary metabolites in root exudates which stimulate symbiotic relationships with AM fungi. Thus, these findings provide insights into genetic mechanisms that underlie higher AM fungal colonization and enhanced invasive plant performance.

Influence of arbuscular mycorrhizal fungi on root foraging and competitive ability depends on soil phosphorus distribution: evidence from two pairs of invasive and native plants

Besides uptake of nutrients by roots, plants can acquire nutrients through arbuscular mycorrhizal fungi (AMF). AMF play a crucial role in plant growth and competition. However, few studies have investigated the effects of AMF on root foraging and competition between invasive and native species in response to heterogeneous nutrients. Two pairs of invasive and native plants of the Asteraceae family were selected to create a common garden experiment involving three factors (heterogeneous vs. homogeneous phosphorus (P), with vs. without AMF, and monoculture vs. mixture). The results showed that AMF significantly reduced the foraging scale of the invasive species, Bidens pilosa, and decreased the precision of the invasive species, Praxelis clematidea, and the native species, Emilia sonchifolia. In monoculture, AMF significantly decreased the total biomass of the two invasive species under heterogeneous P rather than homogeneous P, which was confirmed by N and P uptake. In mixture, heterogeneity significantly decreased the tolerance competitive ability of B. pilosa but increased that of P. clematidea. In the homogeneous P, AMF significantly decreased the suppression ability of B. pilosa, while in the heterogeneous P, AMF decreased that of P. clematidea. Heterogeneous P with AMF increased the suppression ability of B. pilosa but decreased that of P. clematidea. The interactive effects of AMF and soil P distribution on root foraging and nutrient uptake and competition differ among the four species and show invasive-native pair differences. These findings provide valuable insights into the interactive effects and highlight the context dependency of these interactions.

Effect of Aqueous Extract of Ageratum Houstonianum on Seed Germination and Seedling Growth of Triticum Aestivum (Wheat)

Invasive plants are species that do not belong in a particular habitat but enter and establish themselves there. They are known for their adaptability and competitiveness in different environmental conditions. They tend to compete with crops for crucial resources, including water, light, and nutrients and can hinder crop growth and development through allelopathy. The aim of the current research was to investigate the allelopathic effect of aqueous extracts of Ageratum houstonianum on the germination and growth of wheat (Triticum aestivum) seedlings. The aqueous extracts were obtained from the leaves of A. houstonianum at various concentrations, including control, 25%, 50%, and 100%, and applied to pot and petri-plates cultures. The experiment was set up with 5 replicates for both the Petri plates and pot cultures. The study results showed that A. houstonianum aqueous leaf extracts had a significant impact on the germination and growth of T.aestivum. The concentrated (100%) aqueous leaf extracts of A. houstonianum significantly hindered the germination of seeds and growth parameters of T. aestivum. Additionally, the extract treatments of the weed species resulted in changes in soil pH and soil fertility. When invasive weed species grow alongside crops in fields, they may consume a significant number of resources required for crop growth, leading to a decrease in both the quantity and quality of agricultural output. Hence, this study highlights the potential adverse effects of invasive weeds on crop growth and development, and how they can negatively impact agricultural productivity. Therefore, there is a need for effective management strategies to control the spread of invasive weed species and preserve the productivity of agricultural land.

Unraveling local and regional determinants of high plant diversity at marine rocky outcrops in Uruguay

AbstractQuestionsMarine rocky outcrops are model systems of community assembly under harsh conditions. The prevailing environmental conditions that determine a coast–inland gradient of stress and disturbance impose a strong environmental filter on community assembly. However, the Atlantic rocky outcrops of Uruguay challenge this assumption as they exhibit high plant diversity at small spatial scales. We investigated this study system to answer: (1) which environmental factors determine diversity at the local scale; (2) and how does the regional pool influence species composition along the coast–inland gradient?MethodsWe analyzed the local and regional determinants of plant community assembly in four rocky sites along the Uruguayan coast. Through a random sampling approach stratified by distance to the coast, we recorded species occurrences and microenvironmental conditions. Observed taxa were assigned into different species assemblages according to their typical vegetation type. Generalized Linear Model (GLM)–Poisson regression, quantile regressions and hierarchical cluster analyses were used to identify the factors underlying local richness and the spatial vegetation structure.ResultsNine different vegetation types generate a mass effect that enhances local diversity. Unexpectedly, 56% of the species are from non‐marine environments — e.g. grasslands or hydrophilous herblands. Species assemblages were spatially clustered, with a turnover of these clusters along the coast–inland gradient. Elevation, distance to the coast and vegetation cover promoted richness, likely due to an attenuation of marine filters. Meanwhile, substrate availability reduced richness, likely due to competitive exclusion as a result of more resources and homogeneous microenvironmental conditions.ConclusionsThe high local diversity along the marine rocky outcrops of Uruguay is best explained by a functionally diverse regional species pool, which interacts with local heterogeneity, and by conditions that enhance or attenuate the effect of marine stress. Effective conservation and management strategies are key to minimize the detrimental effects of urbanization, fragmentation, and non‐native plant invasions on these diverse habitats.

Preliminary insights of the genetic diversity and invasion pathways of Cedrela odorata in the Galapagos Islands, Ecuador.

Cedrela odorata is considered the second most invasive tree species of the Galapagos Islands. Although it is listed in CITES Appendix II and there are population losses in mainland Ecuador, in Galapagos it is paradoxically a species of concern due to its invasive potential. Genetic studies can shed light on the invasion history of introduced species causing effects on unique ecosystems like the Galapagos. We analyzed nine microsatellite markers in C. odorata individuals from Galapagos and mainland Ecuador to describe the genetic diversity and population structure of C. odorata in the Galapagos and to explore the origin and invasion history of this species. The genetic diversity found for C. odorata in Galapagos (H e = 0.55) was lower than reported in the mainland (H e = 0.81), but higher than other invasive insular plant species, which could indicate multiple introductions. Our results suggest that Ecuador's northern Coastal region is the most likely origin of the Galapagos C. odorata, although further genomic studies, like Whole Genome Sequencing, Rad-Seq, and/or Whole Genome SNP analyses, are needed to confirm this finding. Moreover, according to our proposed pathway scenarios, C. odorata was first introduced to San Cristobal and/or Santa Cruz from mainland Ecuador. After these initial introductions, C. odorata appears to have arrived to Isabela and Floreana from either San Cristobal or Santa Cruz. Here, we report the first genetic study of C. odorata in the Galapagos and the first attempt to unravel the invasion history of this species. The information obtained in this research could support management and control strategies to lessen the impact that C. odorata has on the islands' local flora and fauna.

Predicting the risk of invasion by broadleaf watermilfoil (Myriophyllum heterophyllum) in mainland Portugal

Broadleaf water milfoil (Myriophyllum heterophyllum) is an emerging invasive alien plant in Europe, and thus a priority for European Union (EU)-level surveillance, monitoring, and eradication. This species is native to North America and threatens aquatic ecosystems by creating dense stands that can fill an entire water body, leading to high economic costs and the loss of native biodiversity. Although its presence in Portugal is not reported, the species has already been established in several European countries, including neighboring Spain. In this study, we assessed the risk of invasion by this species in mainland Portugal by jointly considering environmentally suitable areas and the risk of human-mediated introduction. Environmental suitability was estimated using MaxEnt, which relates the known species distribution to climate, topography, and soil variables. The model achieved a mean area under the curve value of 0.96 ± 0.008 and identified the mean temperature of the warmest quarter as the most relevant variable for explaining the species distribution (67.2 %). Predictions from the model indicated that the peaks of suitability values were distributed mainly in temperate climate regions along central and northern coastal areas in Portugal. The risk of introduction was estimated by mapping and calculating the spatial density of the aquarium stores. Jointly considering environmental suitability and risk of introduction, we observed that hotspots at risk of invasion are concentrated on the Portuguese central and northern coasts and in the two main metropolitan areas, Lisbon and Porto. Several risk hotspots fall within protected areas and sites designated under the EU Habitats Directive, comprising water bodies of high significance for maintaining local vegetation and fauna. Therefore, it is necessary to take measures to reduce the risk of invasion by this species, namely, surveillance and monitoring efforts confirming its absence in the national territory and preventing its future arrival.

The Role of Consumers’ Knowledge of Native and Pollinator-friendly Plants and Their Prioritization of Plant Characteristics in Purchase Decisions

There is a growing trend toward planting native and pollinator-friendly plants in residential gardens and landscapes due to concerns about invasive plant species, water conservation, and urban land management. Yet, understanding consumer purchase behavior and how knowledge affects their purchase intent is largely unknown. In this analysis, we integrated national online and in-person surveys to determine the influence of consumers’ subjective and objective knowledge of native and pollinator-friendly ornamental plants on their purchase decisions. Factors influencing plant purchase decisions were measured using a 7-point Likert rating scale. We found that participants with relatively higher knowledge of native and pollinator-attractive plants placed more emphasis on sustainable production methods relative to the plant’s physical attributes (e.g., plant size, shape, etc.) and care-related characteristics (e.g., plant health, easiness of care, etc.). Plant lovers (i.e., frequent purchasers who spent relatively more money on plants than infrequent purchasers) were more likely to prioritize sustainable production methods over the plants’ physical attributes. In contrast, participants primarily buying plants from mass merchandisers/box stores tend to focus on visual appeal or aesthetic characteristics. Consumer marketing implications for the nursery and greenhouse industry stakeholders are discussed.