Invasive Alien Plants Research Articles

PM 3/97 (1) Inspection of consignments of plants for planting for invasive alien plants

<scp>PM</scp> 3/97 (1) Inspection of consignments of plants for planting for invasive alien plants

Revealing How Human Activity and Native Plants Outshine Climate in Shaping New Invasive Alien Plant Elevational Patterns in Nature Reserves

ABSTRACTAimWe aim to investigate whether invasive alien plants introduced at different times exhibit variations in elevational distribution patterns and to explore the correlations of these patterns with climate, native plants and human activity.LocationGuangxi, China.MethodsWe recorded plant richness and cover across elevational gradients at 25–34 sites within each reserve, utilising 84–134 roadside plots per site. Using generalised linear mixed model (GLMM), we assessed the impacts of climate, native plants and human activity on the distributions of all, old and new invasive alien plants across the region and within the nature reserves.ResultsAt regional scales, the cover of all, new and old invasive alien plants decreased with increasing elevation, while only the richness of old invasive alien plants exhibited a similar pattern. Contrasting patterns were observed in Dayao Mountain, where the cover of old invasive alien plants decreased while the cover of new invasive alien plants increased. The richness patterns of all and new invasive alien plants were opposite between Dayao Mountain and Yachang Orchid. Moreover, native plant richness was negatively correlated with the richness of invasive alien plants, while interference intensity positively affected new invasive alien plants at both regional and reserve scales. At the regional scale, native plant richness accounted for 78.27%, 91.94% and 60.9% of all, old and new invasive alien plants respectively. Interference intensity accounted for 33.85% of the variation in new invasive alien plants. Annual mean temperature positively influenced the cover of all and old invasive alien plants at both regional and reserve scales, explaining 36.91% and 74.28% of their regional variation. Additionally, interference intensity and distance to human settlements positively impacted the cover of new invasive alien plants, contributing to 50.95% and 31.92% of their variation at regional scales.Main ConclusionThe distinct distribution patterns of old and new invasive alien plants highlight the significance of residence time in understanding their dynamics. Climate factors constrain the cover distribution of all and old invasive alien plants, whereas interference intensity and distance to settlements determine the distribution of new invasive alien plants. Notably, native plants play a vital role in preventing the establishment and spread of invasive alien plants within nature reserves, and their effectiveness increases with longer residence times. Our findings highlight the critical importance of minimising human interference and conserving native species for the effective management of invasive alien plants in nature reserves.

Odd New Spring: Towards Evolving Landscapes and a Reorientation in Design Practice (2024)

"Odd New Spring: Towards Evolving Landscapes and a Reorientation in Design Practice" is an artistic research PhD project that explores methods for designers to engage with local environments, interdisciplinary communities, and professional fields in new ways. The project repositions unwanted plants, specifically Invasive Alien Plant Species, as a foundation for knowledge creation and new local activities. This approach challenges the perception of these plants as strictly agonistic and reframes them in the context of sustainability, production, and resource management. Through the artistic practice, the plants are connected to stories from the past and visions for the future, encouraging reflection on current classifications and relations. The work culminated in the exhibition "Odd New Spring" at the University Museum in Bergen's Natural History Collections. Here, experimental artefacts, storytelling objects, interdisciplinary dialogues, and reflections point towards a new design position. The project envisions the designer as a bridge-builder across disciplines, fostering sustainable practices and coexistence within local landscapes. Supervised by Mette L'orange (architect MNAL and visual artist) and Tim Parry-Williams (Professor of Art: Textiles, KMD). Photo: Odd New Spring 2024, Siren Elise Wilhelmsen

Evaluation of climate conditions and ecological traits that limit the distribution expansion of alien Lolium rigidum in Japan

Invasive alien plants cause severe global problems; therefore, determining the factors that lead to the success or failure of invasion is a critical question in the field of invasion ecology. In this study, we aimed to determine the factors underlying differences in the distribution range of alien plants in Japan by investigating why Lolium multiflorum thrives in a wide range of habitats while L. rigidum is mainly distributed on sandy beaches. We initially evaluated environmental niche suitability through species distribution modelling and subsequently examined whether species traits influence the differences in range expansion between the two species. We used MaxEnt modelling to identify potential environmental niches for both species. The analysis revealed that L. rigidum was considerably less suited to the Japanese climate compared to L. multiflorum, with high summer precipitation in Japan identified as one of the climatic factors limiting the distribution of L. rigidum. Given that these winter annual plants remain dormant as seeds during summer, in subsequent experiments, we buried seeds in paddy field soil and sandy beach sand during summer and evaluated their survival rate in autumn. The survival rate of L. rigidum seeds was significantly lower than that of L. multiflorum, particularly in paddy soil. Factors contributing to seed mortality may include the decay or early germination of L. rigidum seeds under Japan’s high rainfall conditions. This study emphasises the importance of considering local environmental factors alongside climate niche modelling in the risk assessment of invasive species. Moreover, the integration of species distribution modelling for large-scale evaluations and manipulation experiments for fine-scale assessments proved effective in identifying climatic conditions and species traits influencing the success or failure of alien species invasion.

An ecoregion-based approach to evaluate invasive plant species pools

Invasive alien species are an important component of global change, threatening biodiversity, ecosystem functioning, economy, and human health. The number of alien species that attain the invasive status has experienced an exponential increase in recent years, leading some government agencies and stakeholders to allocate substantial resources to early detection, control, mitigation, and eradication programs. To develop effective nature conservation strategies, it is crucial to understand the invasive status of alien species and to identify priority species for management at spatial scales with a biogeographical basis. Despite significant progress in producing lists of alien species at the country level, a standard methodology for species assessment within ecological regions (i.e., regions with similar environmental or biogeographical characteristics) is still lacking. Here, we develop a systematic approach to determine invasion status and to prioritize invasive alien plant species within an ecoregion. We apply this approach in the Cantabrian Mixed Forests ecoregion, which encompasses biogeographically related areas from N Portugal, NW Spain, and SW France, and is strongly affected by plant invasions. By combining scientific evidence with expert opinion on the ecological characteristics of alien plants, we identified 175 invasive plant species in the study ecoregion, of which 37 cause massive environmental and/or socio-economic impacts. For each species, we provide comprehensive information and recommendations for scientists, land managers, policy makers, and other stakeholders under a biogeographical basis. This information includes species characteristics, invasion status/level, population trends, geographic locations and range size, local abundance, environmental and socio-economic impacts, and invaded habitats. We also accounted for administrative divisions within the ecoregion to facilitate the use of such evaluations in local-scale management and conservation plans. Our framework may be applied to any ecoregion worldwide, enhancing the assessment and management of invasive species pools within biogeographically meaningful regions.

Assessing the status of soil seed bank in Parthenium hysterophorus invaded land use types and its social aspects in Lower Hare Watershed, Southern Ethiopia

In Ethiopia, Parthenium hysterophorus (P. hystrophorus) is an invasive alien plant affecting various ecosystems. P. hysterophorus displaced native plant species and caused a serious threat to biodiversity. This study aimed to assess soil seed bank of P. hysterophorus under major land use types and assess community perception towards the effects of P. hysterophorus on social aspects in lower Hare watershed. For this study, 210 soil samples were collected from fifteen transect lines in grassland, cropland, and forest land use types. Statistical analysis using three ways factorial ANOVA was used to analyze the difference in density of P. hysterophorus among various land uses soil depths, and sites (P &lt; 0.05). For the perception of local communities regarding the effects of P. hysterophorus, a total of 117 respondents were used and semi-structured and close-ended questionnaires for data collection. It found that all factors: land use, site, and soil depth significantly affected the soil seed bank density in the lower Hare watershed (P &lt; 0.05). Results indicated that mean density of seeds were the highest in croplands of other land use types. Meanwhile, the highest mean density of seeds was identified in 0-10 cm soil depth, but the lowest mean density of seeds was identified in 10-15 cm soil depth. The highest seeds were identified at Chano Cheliba, but the density of seeds the lowest in density at Kola Shera. 38.5% of households in Kola Shera, and 21.4% in Kola Cheliba, but 8.5% in Kola Doriga said that it had effects on ecosystem services such as crop yield and livestock production. There should be a need for increased awareness about the density of P. hysterophorus in various land uses and its impacts on native plant species. Seeking possible solutions such as biological and mechanical control methods are among the local people, researchers, and extension workers can use for the management of its invasion, and appropriate control measures can be designed to combat its further invasion and impacts on different land uses of the region.

Biodiversity and plant-insect interactions in fragmented habitats: A systematic review

Abstract Fragmentation is threatening insect biodiversity and intricate interactions in various ecosystems. Ecological interactions – especially those involving plants and insects – are significantly impacted by fragmented habitats. Because of fragmentation, edge effects and reduced habitat connectivity and quality affect insect species diversity, abundance, behavior, movement, life cycles, and interactions with plants, e.g., pollination, herbivory, and seed distribution. To a large degree, ecosystem services or processes are mediated by these interactions. While fragmented habitats create suitable conditions for invasive alien plants (IAPs), such invasions modify native plant composition and herbivorous insect communities because they cause a decline or loss in insect biodiversity. A systematic review was conducted by reviewing eighty-eight (88) articles to gather evidence for fragmentation effects on insect biodiversity, insects’ behavior and adaptations, plant-insect interactions (i.e., pollination, herbivory, and seed dispersal), and its influence on IAP invasions. This review deduced that any change in insect community composition and diversity due to fragmentation can have cascading effects on ecosystem processes within habitats. It further contends that successful conservation and management of fragmented habitats requires an understanding of the intricate dynamics of plant-insect interactions. However, the long-term resilience and health of ecosystems can be guaranteed by supporting sustainable land use, improving connectivity, and restoring habitats. These actions may help stop and/or reduce the effects of fragmentation on insect biodiversity and support the livelihoods and well-being of millions of people.

Contrasting responses of an invasive plant to herbivory of native and introduced insects

BackgroundInteractions between alien plants and insect herbivores in introduced ranges may determine their invasion success. However, few studies have investigated whether alien plants respond differently to native and introduced herbivores in their introduced ranges and whether genotypes of alien plants matter. We conducted a greenhouse experiment to examine the effects of herbivory by a native insect (Spodoptera litura), by an introduced insect (S. frugiperda), and simultaneously by both insect species on growth, morphology, and biomass allocation of 17 genotypes of an invasive alien clonal plant Hydrocotyle verticillata, and used selection gradient analysis to test which herbivory conditions favor selection of a specific leaf or root trait value.ResultsDifferent genotypes of H. verticillata showed significant variation in growth, morphology, and biomass allocation, but their responses to herbivory were relatively consistent. All three herbivory treatments significantly decreased total mass and stolon mass, but herbivory of S. frugiperda increased specific leaf area. Herbivory of S. litura and simultaneous herbivory of both insect species also decreased leaf mass, petiole mass, root mass, and ramet mass. Selection gradient analysis showed that leaf and root traits varied under different herbivory treatments. To achieve greater fitness, as measured by total mass and/or number of ramets, H. verticillata favored larger leaf area under herbivory by S. frugiperda, larger leaf area and lower specific leaf area under herbivory by S. litura, and larger leaf area, lower specific leaf area, and lower root-to-shoot ratio under simultaneous herbivory.ConclusionsH. verticillata demonstrated contrasting responses to herbivory by native and introduced insects, showing a remarkable ability to coordinate leaf trait plasticity and optimize biomass allocation. This strategy allows H. verticillata to achieve greater fitness under various herbivory conditions, potentially contributing to its invasion success. These findings highlight the importance of plant–herbivore interactions in shaping invasion dynamics and underscore the complex adaptive mechanism that enables invasive plants to establish and spread in introduced ranges.

Montane grassland recovery: lessons from 25 years of the Working for Water program on the northern Drakensberg Escarpment, South Africa

Despite their strategic importance as biodiversity hotspots and water sources, montane ecosystems are among the most neglected conservation areas. In particular, the monitoring and management of invasive alien plants in this critical biome is limited. This study presents an analysis of long‐term invasive alien plant removal within montane grassland ecosystems, drawing on insights from 25 years of the Working for Water (WfW) program on the northern Drakensberg Escarpment. We assessed the response of vegetation communities to invasive alien plant removal in this region. Using data from the WfW program on clearance activities, expenditure, and re‐visit times, we compared plant species richness, diversity, and composition in sites managed under the WfW program to adjacent patches of pristine vegetation. Results showed minimal variation in species richness between cleared sites and unmanaged sites. However, these vegetation communities remain distinctly dissimilar across sites. These findings suggest the need for active restoration of montane vegetation communities if they are to return to their natural condition and further highlight the need to conserve the remaining habitats for critically endangered species, even in their depauperate state.

Early Molecular Detection of Invasive Alien Plants in Urban and Peri-Urban Areas

Invasive alien plants represent one of the five major threats to biodiversity and the disruption of ecosystems. They are introduced through various routes, starting with commercial trade. Preventing their introduction is essential to avoid the spread of new invasive plants. In this paper, we propose a new early warning DNA barcoding tool for invasive plant detection. Eight invasive alien species of European Union concern (i.e., Ludwigia grandiflora, Elodea nuttallii, Myriophyllum aquaticum, Pontederia crassipes, Ailanthus altissima, Heracleum mantegazzianum, Impatiens glandulifera, Pueraria montana) were selected and analysed. A unique DNA marker for each species was identified and amplified using species-specific primers capable of identifying the presence of alien species. To verify whether the approach could detect the presence of alien plants in urban areas from lawn clippings, mixes with typical urban spontaneous plants and invasive species were tested. In all mixes, only the invasive species was identified. This rapid detection capability will enable environmental operators to intervene promptly to contain the spread of invasive plants before they can cause significant damage to the local ecosystem. This tool could have a significant impact on the protection of local biodiversity and the integrity of urban habitats.

Interpreting the shifts in forest structure, plant community composition, diversity, and functional identity by using remote sensing-derived wildfire severity

BackgroundWildfires are increasingly impacting ecosystems worldwide especially in temperate dry habitats, often interplaying with other global changes (e.g., alien plant invasions). Understanding the ecological consequences of wildfires is crucial for effective conservation and management strategies. The aim of this study was to investigate the impacts of wildfire severity on plant community (both the canopy trees and herbaceous layer) and alien plant invasion, combining field observations and remotely sensed data.We conducted an observational study in the Karst forests (North-East Italy) 1 year after the large wildfire which affected the area in 2022. We assessed the impact through 35 field plots (200 m2 each) distributed among different fire severity (i.e., the loss of organic matter) classes assessed using the differenced normalized burn ratio (dNBR) calculated from satellite images. In each plot, tree species, diameter, vitality, resprouting capacity, and seedling density were measured. In addition, herb species richness (taxonomical diversity) was quantified, and plant cover was visually estimated. Functional diversity was also assessed considering six functional traits retrieved from databases.ResultsSome woody species (e.g., Quercus pubescens) showed a higher resistance to the fire (i.e., lower mortality rate), while others showed a higher resilience (i.e., recovery after fire through resprouting or seedlings, e.g., Cotinus coggygria). The transition to a shrub-dominated community (i.e., Cotinus coggygria) where fire severity was the highest underlines the dynamic nature of the post-fire succession. We detected a significant variation in the herbaceous plant community composition, diversity, and functional identity (i.e., community-weighted mean of trait) along the fire severity gradient. In particular, high-fire severity areas exhibited higher species richness compared to low-severity or unburned areas. Total alien plant cover increased with fire severity, while native cover remained constant. We also found shifts in species that enhance traits related to germination potential and growth strategy.ConclusionsOur results highlight the vulnerability of the forest stands to an increase in wildfire severity, resulting in significant mortality and changes in tree community structure. This study contributes to the understanding of ecological processes after wildfires using a novel remote sensing approach in a temperate forest, emphasizing the need for conservation strategies aimed at mitigating high severity wildfires.

Biological invasions threaten crops: Alien Himalayan balsam lures and co-opts floral visitors away from cultivated cherry tomatoes

While it has been demonstrated that invasive alien plants pose a threat to co-occurring wild-growing native plants by attracting their pollinators, we know almost nothing about their impact on crop pollination. Alien plants with attractive flowers sometimes occur close to crops and may influence yields when they share the same pollinators and have overlapping flowering periods. We present the results of an experiment on the impact of alien balsam (Impatiens glandulifera) on the pollination of cherry tomato (Solanum lycopersicum var. cerasiforme). We verified whether balsam decreases the number of insect visits to the tomato flowers or, conversely, whether balsam may have a positive influence on the pollination rate of the crop. We also assessed crop production with and without the insect visitors. The study was conducted in southern Poland under garden and greenhouse experimental conditions simulating small-scale cultivation of the crop with a neighbouring patch of the alien plant. The studied plants were exposed to insects visiting flowers of the following variants: only one of the two species was exposed or both species were exposed together. Moreover, two factors that may influence insect visits in flowers were assessed: the chemical composition of the floral scent that attracts insects and floral pathogens infesting pollinators that may deter them. The number of insect visits (mainly Bombus pascuorum) on the tomato flowers decreased significantly when the plants were exposed to the alien balsam. Moreover, alien balsam secreted more flower attractants (mainly fatty acids and their esters) than tomatoes, which could explain more frequent insect visits in balsam flowers. However, the floral pathogens probably had a negligible impact on the number of insect visits to the flowers of the two plants. The level of infestation on both studied species was relatively low (I. glandulifera: 5.1% of all pathogen colonies grown in a laboratory, S. lycopersicum var. cerasiforme: 4.2% and 2.6% of all colonies in the garden and greenhouse, respectively) and we found no pathogens known to infect pollinators. It should be noted, however, that some of these pathogens (e.g. Botrytis cinerea, Fusarium oxysporum and Sclerotinia sclerotiorum) are known to cause severe diseases in many crops. Our results revealed that the presence of attractive invasive alien species near small-scale cultivations may negatively affect crop pollination, resulting in smaller fruit size and irregular shape. The impact of such alien species on crop production and the agricultural economy on a large scale requires further study.

Natural enemies of Lemna minuta in its native range and their potential as biological control agents for Europe

ABSTRACT Lemna minuta is native to North America but an invasive alien plant in Europe, where it poses significant threats to freshwater ecosystems. Explorations for biological control agents were conducted in two regions of the United States (Louisiana and California), revealing three candidate species. Subsequent laboratory investigations focused on the weevil Tanysphyrus lemnae and the fly Lemnaphila scotlandae as the most promising agents and confirmed that both the herbivorous insects attack L. minuta plants. To evaluate the host specificity of these two potential agents, insects were exposed to five species of duckweed commonly occurring in North America and Europe. Preliminary host-range testing indicated that T. lemnae develops on all evaluated duckweed species, including those from different genera (Lemna, Spirodela, Landoltia). Conversely, data revealed that feeding and development of the dipteran L. scotlandae are limited to species in the genus Lemna, but this includes L. minor, a native European species threatened in Europe due to the spread of L. minuta. No-choice and choice tests confirmed that neither larvae nor adults of L. scotlandae discriminate between the two Lemna species, except for pupation, which occurs more frequently in L. minor under choice conditions. We conclude that the broad host-range of T. lemnae and L. scotlandae render them unsuitable as biological control agents of L. minuta in Europe.

Bacterial and fungal keystone taxa play different roles in maintaining community resistance and driving soil organic carbon dynamics in response to Solidago Canadensis invasion

The invasion of alien plants has significant implications for vegetation structure and diversity, which could lead to changes in the carbon (C) input from vegetation and change the transformation and decomposition processes of C, thereby altering the dynamics of soil organic carbon (SOC) within ecosystems. Whether alien plant invasion increases the SOC stock and changes SOC fractions consistently within regional scales, and the underlying mechanisms driving these SOC dynamics remain poorly understood. This study investigated SOC dynamics by comparing the plots that suffered invasion and non-invasion of Solidago Canadensis across five ecological function areas in Anhui Province, China, considering climate, edaphic factors, vegetation, and soil microbes. The results demonstrated that the impact of S. Canadensis invasion on SOC storage was not consistent at each site in the 0–20 cm soil layer, as indicated by the range of SOC content (5.94–12.45 g kg−1) observed at non-invaded plots. Stable SOC exhibited similar response patterns with SOC to plant invasion, whereas labile SOC did not. In addition, bacterial and fungal communities were shifted in structure at each site by plant invasion. Bacterial communities exhibited greater resistance to S. Canadensis invasion than did fungal communities, as evidenced by three aspects of the resistance indices—community resistance, phylogenetic conservation, and network complexity. The mechanisms driving SOC dynamics under S. Canadensis invasion were explored using structural equation models. This revealed that fungal keystone taxa responsible for community resistance controlled stable SOC fractions. In contrast, bacterial keystone taxa had the opposite effect on labile and stable SOC. Climatic and edaphic factors were also involved in the labile and stable SOC dynamics. Overall, this study provides novel insights into the dynamics of SOC under S. Canadensis invasion on a regional scale.

Asian knotweed’s impacts on soil chemistry and enzyme activities are higher in soils with low-nutrient status

Invasive alien plants such as Reynoutria spp. can drastically affect the composition of plant communities. Yet, whether and how these species also affect soil physicochemical properties and microbial functioning is still an unresolved question in the literature. Using a space-for-time substitution approach comparing invaded to uninvaded adjacent plots, we estimated the impacts of Reynoutria on soil biochemistry across nine contrasted sites in France by measuring soil carbon content, nutrient availability and enzyme activities. Soil under Reynoutria displayed higher carbon, nitrogen and phosphorus contents but no differences were detected regarding enzyme activities between invaded and uninvaded sites. Moreover, the magnitude of Reynoutria’s effects differed depending on local conditions, with greater effects when total carbon and phosphorus-related enzymes were relatively low. These data highlight that changes in soil nutrient availability might be primarily due to direct effects of Reynoutria on soil properties and microbial functioning. Higher impacts were observed in soils with low-nutrient status, suggesting a ‘niche construction ability’ of Reynoutria. Our results underscore the necessity of considering the context-dependency of Reynoutria on soil biochemistry and highlight that the impact of alien species belowground functioning depends on initial soil conditions.

Impact of invasive alien plants on the resident floral diversity in Koshi Tappu Wildlife Reserve, Nepal.

Invasive alien plant species (IAPS) pose a serious threat to overall plant biodiversity across the globe. Nepal's national parks and protected areas are not devoid of the impact of IAPS. Unfortunately, there is a substantial gap in knowledge regarding the extent and impact of invasion in protected areas of Nepal. This study assessed the impact of invasive alien plant species on the resident plant species of the Koshi Tapu wildlife reserve. After a preliminary field observation, we selected five major IAPS in the area, Mesosphaerum suaveolens, Chromolaena odorata, Ipomoea carnea, Lantana camara, and Mikania micrantha for this study. Ten pairs of adjacent plots sized 4 m × 4 m were surveyed for each invasive species, comprising diverse vegetation types. Each pair consisted of one "invaded plot" where the invasive species was dominant with cover greater than 50%, and another "uninvaded plot" laid out in an adjacent area with similar site conditions but without the invasive species. We calculated the Sørensen Index of Similarity for each paired plot. Wilcoxon rank-sum test was employed to compare ecological parameters between invaded and uninvaded plots for various plant species. Similarly, the difference in impact between each of the five invasive species was assessed using the Kruskal-Wallis test. Species richness varied significantly between invaded and uninvaded plots for C. odorata and I. carnea. The most significant impact on species composition of invaded communities (39.6%) was observed for C. odorata. The cover of the other dominant species varied significantly between invaded and uninvaded plots for all five species studied. The Kruskal-Wallis test showed no significant difference in the impact caused by the five studied invasive species on Species richness, Shannon-Wiener diversity index, species evenness, and height of dominant species. However, a significant difference was observed between the impacts of five studied invasive species and the cover of other dominant species. The crown cover of dominant species decreased much more in the invaded plots of L. camara and M. micrantha than in other species. Specialized management efforts are required to control highly invasive species, such as C. odorata and I. carnea, alongside proactive measures to prevent further spread in ecologically sensitive areas.

Associations between Lantana camara L. (Verbenaceae) and common native species in an African savanna

Abstract Lantana camara L. (Verbenaceae) is recognised as a problematic invasive alien plant species in many parts of the world. To eradicate or control this global invader, we need to understand the drivers of its spread and impacts and the potential for native recovery after the invader has been removed. Here, we tested for species associations between L. camara and native plant species and large herbivores in Queen Elizabeth National Park, Uganda. We inventoried 40,100‐m2 nested plots spread over a 1 × 1‐km grid cell in the park's savanna landscape, with 11 plots located in uninvaded areas. Most of the plots (30 of 40) had been affected by fire. Lantana camara covered 29 (73%) plots, 11 (38%) of which were in open grassland. Of the large herbivores that frequented areas free of L. camara, the Ugandan kob Adenota kob thomasi Sclater tended to avoid the areas invaded. The floristic composition of invaded areas differed significantly from that of noninvaded areas, with several palatable species rare or absent from L. camara‐invaded areas. Practical implication: These observations indicate the presence of potential recovery constraints that will need to be overcome after L. camara has been removed. Sustained efforts will be needed to suppress the invader and subsequently enrich and bolster native recovery.

Invasive Alien Plant Species Aqueous Extracts in a War Against the Granary Weevil (Sitophilus granarius [L.]) – are They Long-Term Effective or Can They Only Win the Battle of Cannae?

This study investigates the effectiveness of plant-based extracts in repelling the granary weevil (Sitophilus granarius), a common storage pest causing significant economic losses. The selected plant species (Canadian goldenrod, giant goldenrod, indigo bush, staghorn sumac, and tree of heaven), were examined for their repellent effects on weevils in grain samples. Surprisingly, the short-term repellent effects observed after 24 hours diminished after 3 days, suggesting potential challenges for practical applications, especially in long-term grain storage. Temperature emerged as a significant environmental factor, influencing weevil behavior. Lower temperatures created an illusion of increased effectiveness, while higher temperatures accelerated weevil reproduction. Commercial product NeemAzal, despite its reputation for effectiveness, proved the least potent among all treatments, raising questions about its applicability in such cases. Progeny emergence tests indicated no significant differences between treatments, emphasizing the ineffectiveness of the extracts in sustaining long-term repellent effects. The study concludes that while plant-based extracts may offer short-term victories in pest control, their long-term efficacy remains uncertain. The complex interplay of factors, including temperature and humidity, highlights the challenges in developing sustainable and practical solutions for grain storage pest control, necessitating careful consideration by real-world users.

Anthropogenic disturbance and alien plant invasion drive the phylogenetic impoverishment in riparian vegetation

Anthropogenic disturbance and alien plant invasion drive the phylogenetic impoverishment in riparian vegetation

Geographic variation in leaf traits and palatability of a native plant invader during domestic expansion.

Like alien plant invasion, range expansion of native plants may threaten biodiversity and economies, rendering them native invaders. Variation in abiotic and biotic conditions across a large geographic scale greatly affects variation in traits and interactions with herbivores of native plant invaders, which is an interesting yet mostly unexplored issue. We used a common garden experiment to compare defensive/nutritional traits and palatability to generalist herbivores of 20 native (23.64° N-30.18° N) and introduced range (31.58° N-36.87° N) populations of Reynoutria japonica, which is a native invader following range expansion in China. We analyzed the relationships among herbivore pressure, climate, plant chloroplast haplotypes, leaf traits, and herbivore performance. Of the 16 variables tested, we observed range differences in 11 variables and latitudinal clines in nine variables. In general, herbivores performed better on the introduced plants than on the native plants, and better on the high-latitude plants than on the low-latitude plants within the introduced populations. Three key traits (leaf thickness, specific leaf area, and carbon-to-nitrogen [C:N] ratio) determined palatability to herbivores and were significantly associated with temperature and/or precipitation of plant provenance as well as with plant haplotypes but not with herbivore pressure. Our results revealed a causal sequence from plant-range-based environmental forces and genetic context to plant quality and palatability to herbivores in R. japonica. These findings suggest a post-introduction evolution of R. japonica, which may partly explain the colonization success of this important native, but invasive plant.