Alien Plants Research Articles

Impact, management, and use of invasive alien plant species in Nepal’s protected area: a systematic review

Impact, management, and use of invasive alien plant species in Nepal’s protected area: a systematic review

Habitat context and functional growth traits explain alien plant invader impacts on native vegetation communities

Examining context-dependency of ecological impacts of alien plant invasions is critical to further understand the mechanisms driving impacts. We examined how different regional and local habitat contexts influence the abundance-impact associations of an invasive ground-creeper, Tradescantia fluminensis, in native forests across eastern New South Wales (NSW), Australia. Invader impacts were assessed using surveys of resident vegetation at 97 monitoring plots (5 m × 2 m) located at 14 sites, representing a gradient of T. fluminensis abundance. We modelled the association of T. fluminensis invasion with native species richness (number per plot) and foliage cover across two different habitat types (remnant vs replanted forests), two vegetation community types (wet sclerophyll vs river oak forests), and two regions (northern vs. southern NSW). We also modelled variation in native species responses amongst different functional growth forms. The negative associations of T. fluminensis and native species communities was more strongly explained by local site variables (i.e., habitat type, community type, plant growth form) than regional scales. Native richness reduced with invasion in river oak but not wet sclerophyll forest. Native richness also declined in remnant forest, although no effect of invasion was observed in replanted forest. Surprisingly, native species growth forms most like T. fluminensis (ground layer herbs, ferns) were more resistant to reductions in native richness compared to divergent forms (shrub, tree and woody vine recruits). This study highlights the need to explicitly consider local community and habitat context and functional representation of resident species when considering invader impacts and site-level management plans.

Knowing the invader: increasing knowledge about an invasive plant to improve management

Pampas grass is an invasive alien plant with negative consequences for ecosystems, human health, and economy. Although diverse aspects of its biology and the ecology have been studied, some information relevant to its management is still missing. We studied the ecological characteristics of seeds and plants relevant to management and habitat restoration, namely morphological and reproductive traits in female and hermaphrodite plants, flower development, seed longevity, and germinability under different conditions. Female and hermaphrodite plants showed significant differences regarding reproductive traits, but not for morphological traits. Female plants are largely responsible for the dispersal of the species, while hermaphrodite plants primarily serve as pollen donors, contributing to off‐season allergies. In general, seeds of female plants are mature 3–4 weeks from the onset of flower development and are dispersed by wind until after 4 months, but timings are influenced by weather conditions. The species is very adaptable and can germinate in different soils (85% in fluvisols, 65% in podzols, and 35% in solonchak), water salinities (77 and 75% in freshwater, 28 and 38% in mesohaline, and 7 and 35% in polihaline waters, in laboratory and field, respectively), and moisture conditions (50 and 33% in soaked conditions, and 25 and 80% in moistened conditions, in laboratory and field, respectively). Seeds lack dormancy, are short‐lived (up to 1 year in the field and 3 years in optimal storage conditions), and are easily destroyed at 40°C temperatures in dark conditions. Implications of these findings for the management of the species are discussed.

The effects of dry heat and steam on germination of dry and imbibed seeds of the invasive garden lupine (Lupinus polyphyllus Lindl.)

Abstract Regularly mown road verges are an important habitat for conservation of grassland vegetation. Disturbance and movement of seed-contaminated soil during road construction and maintenance makes road verges susceptible to the establishment of invasive alien plants such as garden lupine (Lupinus polyphyllus Lindl.). To combat spread of L. polyphyllus via seeds, we tested methods for seed destruction using heat. This study aimed at developing heat eradication methods for dry and imbibed L. polyphyllus seeds applying dry heat (88, 93, 98, 103 C at 1, 3, 5, 10 min) in a laboratory, steam (85, 90, 95 C at 3, 5, 10 min) in a test-box steaming device and (97 C at 10-17 min; dry seeds only) in a stationary soil-steaming machine (S30). In order to speed up water absorption and post-treatment germination, the imbibed seeds were manually scarified before the heat treatment and the dry seeds afterwards. Additionally, germination of two different age seed batches was tested applying dry heat (88, 98 C at 3, 5 min). The results showed that steam treatments inhibited seed germination more than dry heat in both dry and imbibed seeds. Germination dropped to < 5% when steamed at ≥ 90 C or dry-heated at > 100 C. Seed germination decreased with higher temperatures and longer exposure times. Imbibed seeds exhibited lower germination compared to dry seeds for dry and steam heat. Approximately 0.5% of dry seeds germinated when steamed using S30. 2022-collected seeds were less sensitive to dry heat than seeds from 2020. In conclusion, hot steam is more effective in reducing L. polyphyllus seed germination than dry heat. Thus, to successfully eradicate L. polyphyllus seeds in soil masses, we recommend steaming them at 97 C for at least 10 minutes.

Introduction Pathways of Invasive Alien Plants in the Lake Cluster of Pokhara Valley, Nepal

The Lake Cluster of the Pokhara Valley (LCPV), a Ramsar site, has been invaded by several invasive alien plant species (IAPS), yet the introduction pathways of these species remain unknown. In this paper, the possible introduction pathways and invasion history of five wetland IAPS of the LCPV have been identified and reported for analysis. Direct field observations were combined with data obtained from the questionnaire survey with the local residents to identify introduction pathways and invasion history. Among five invasive alien plants, Pontederia crassipes and Pistia stratiotes were introduced as ornamental plants that escaped to wetlands and established their populations during 1980s and 1990s respectively. Similarly, Ipomoea carnea subsp fistulosa was introduced during the 1990s for fencing and soil bioengineering purposes. It is highly likely that Leersia hexandra and Alternanthera philoxeroides were introduced accidentally as none of the local residents interviewed could explain the purpose of their introduction. The local residents have noticed the occurrence of L. hexandra for >50 years while A. philoxeroides might have reached to the LCPV sometime between 2015 and 2020. The results suggest the wetland IAPS have been introduced to the LCPV both intentionally as well as accidentally, and that the prioritizing pathway management can prevent their future introductions.

Are impacts of the invasive alien plant Crassula helmsii mediated by detritus? A litter experiment in a temperate pond

Are impacts of the invasive alien plant Crassula helmsii mediated by detritus? A litter experiment in a temperate pond

Negative conspecific plant-soil feedback on alien plants co-growing with natives is partly mitigated by another alien

Abstract Background and aims Naturalized alien and native plants can impact each other directly when they grow next to each other, but also indirectly through their soil legacies. These alien-native interactions can also be modified by the presence of a third alien or native species. However, it is unknown how the performance of co-growing alien and native species is affected by their soil legacies and by the presence of an additional species. Methods In our two-phase plant-soil-feedback experiment, soils were first conditioned by eight herbaceous species, four of which are naturalized and four of which are native to Germany. We then grew all 16 pairwise alien-native species combinations on soil conditioned by the respective alien or native species, on a mixture of soils conditioned by both species or on control soil. Each pair of test plants was grown on these soils without or with an additional alien or native species. Results Soil conditioning, and particularly conspecific soil conditioning, reduced growth of the alien and native test plants. The addition of another species also reduced growth of the test plants. However, the negative conspecific soil-legacy effect on alien test plants was reduced when the additional species was also alien. Conclusion The negative conspecific plant-soil feedback for alien and native plants in our study could promote their coexistence. However, as partial alleviation of negative conspecific effects on alien plants occurred with an additional alien species, the chances of coexistence of alien and native species might decrease when there are multiple alien species present.

Alien emergent aquatic plants develop better ciprofloxacin tolerance and metabolic capacity than one native submerged species

Antibiotic pollution and biological invasion pose significant risks to freshwater biodiversity and ecosystem health. However, few studies have compared the ecological adaptability and ciprofloxacin (CIPR) degradation potential between alien and native macrophytes. We examined growth, physiological response, and CIPR accumulation, translocation and metabolic abilities of two alien plants (Eichhornia crassipes and Myriophyllum aquaticum) and one native submerged species (Vallisneria natans) exposed to CIPR at 0, 1 and 10 mg/L. We found that E. crassipes and M. aquaticum's growth were unaffected by CIPR while V. natans was significantly hindered under the 10 mg/L treatment. CIPR significantly decreased the maximal quantum yield of PSII, actual quantum yield of PSII and relative electron transfer rate in E. crassipes and V. natans but didn't impact these photosynthetic characteristics in M. aquaticum. All the plants can accumulate, translocate and metabolize CIPR. M. aquaticum and E. crassipes in the 10 mg/L treatment group showed greater CIPR accumulation potential than V. natans indicated by higher CIPR contents in their roots. The oxidative cleavage of the piperazine ring acts as a key pathway for these aquatic plants to metabolize CIPR and the metabolites mainly distributed in plant roots. M. aquaticum and E. crassipes showed a higher production of CIPR metabolites compared to V. natans, with M. aquaticum exhibiting the strongest CIPR metabolic ability, as indicated by the most extensive structural breakdown of CIPR and the largest number of potential metabolic pathways. Taken together, alien species outperformed the native species in ecological adaptability, CIPR accumulation and metabolic capacity. These findings may shed light on the successful invasion mechanisms of alien aquatic species under antibiotic pressure and highlight the potential ecological impacts of alien species, particularly M. aquaticum. Additionally, the interaction of antibiotic contamination and invasion might further challenge the native submerged macrophytes and pose greater risks to freshwater ecosystems.

Supplementation of Acacia dealbata versus Acacia mearnsii leaf-meal has potential to maintain growth performance of lambs grazing low-quality communal rangelands in South Africa

Supplementing livestock grazing communal rangelands with leaf-meals from Acacia trees, which are currently considered as problematic invasive alien plants globally, may be a sustainable way of exploiting their desirable nutritional and anthelmintic properties. The current study evaluated worm burdens and growth performance of lambs grazing low-quality communal rangelands supplemented with leaf-meals prepared from the invasive alien plant species; Acacia mearnsii or A. dealbata. Forty, three-month-old ewe lambs weighing an average of 18.9 ± 0.60 kg were randomly allocated to four supplementary diets: (1) rangeland hay only (control), (2) commercial protein supplement plus rangeland hay, (3) A. mearnsii leaf-meal plus rangeland hay and (4) A. dealbata leaf-meal plus rangeland hay. All the supplementary diets were formulated to meet the lambs’ minimum maintenance requirements for protein. All the lambs were grazed on communal rangelands daily from 0800 to 1400 after which they were penned to allow them access to their respective supplementary diets until 08:00 the following morning. The respective supplementary diets were offered at the rate of 400 g ewe− 1 day− 1 for 60 days. Lambs fed the commercial protein supplement had the highest dry matter intake followed by those fed the Acacia leaf-meals and the control diet, respectively (P ≤ 0.05). Relative to the other supplementary diets, lambs fed the commercial protein supplement and A. dealbata leaf-meal had higher (P ≤ 0.05) final body weight and average daily gains. Dietary supplementation did not affect lamb faecal worm egg counts over the study period (P > 0.05). There was no association between supplementary diets and lamb FAMACHA© scores (P > 0.05). It was concluded that supplementation of Acacia dealbata versus Acacia mearnsii has the potential to emulate commercial protein in maintaining growth performance of lambs grazing communal rangelands in the dry season.

Fire suppression and land-use strategies drive future dynamics of an invasive plant in a fire-prone mountain area under climate change

Woody invasive alien species can have profound impacts on ecosystem processes and functions, including fire regulation, which can significantly affect landscape resilience. Acacia dealbata, a widespread invasive alien plant in the Iberian Peninsula, holds well-known fire-adaptation traits (e.g., massive soil seed banks and heat-stimulated seed germination). In this study, we assess to what extent fire suppression and land-use strategies could affect the potential distribution of A. dealbata in a fire-prone transboundary protected mountain area of Portugal and Spain, using Habitat Suitability Models. Specifically, we predicted changes in habitat suitability for A. dealbata between years 2010 and 2050. We explored the potential impacts of two land-use strategies ('Business-as-usual' or 'High Nature Value farmlands') combined with three levels of fire suppression effectiveness using the biomod2 package in R. We also considered the potential effects of two climate change scenarios (RCP4.5 and RCP8.5). Our modeling approach demonstrated a strong capacity to predict habitat suitability using either climate or land-cover information alone (AUC climate = 0.947; AUC LC = 0.957). According to climate-based models, A. dealbata thrives under conditions characterized by higher precipitation seasonality, higher precipitation in the warmest month, and higher minimum temperature in the coldest month. Regarding land cover, A. dealbata thrives mainly in landscapes dominated by urban areas and evergreen forest plantations. Our models forecasted that habitat suitability by 2050 could either increase or decrease depending on the specific combinations of fire suppression, land-use, and climate scenarios. Thus, a combination of business-as-usual and fire-exclusion strategies would enhance habitat suitability for the species. Conversely, management promoting High Nature Value farmlands would decrease the available suitable habitat, particularly under low fire suppression efforts. These findings suggest that promoting sustainable farming activities could impede the spread of A. dealbata by reducing habitat availability, while strategies aiming at fire-exclusion could facilitate its expansion, likely by enabling establishment and large seed production. This study highlights the complex interplay between fire-prone invasive species, fire and land-use strategies, and climate change; and thus the need to consider the interactions between land-use and fire management to promote invasive species control and landscape resilience.

INVASIVE ALIEN PLANTS OF COTE DIVOIRE: AN UPDATE AND PROPOSED CLASSIFICATION BASED ON ENVIRONMENTAL IMPACTS

Background and aims: Scientific data on alien plants and classification of invasive alien plants on the basis of environmental impacts are lacking in Cote dIvoire. The present study was carried out to improve the knowledge on exotic and invasive plants in Cote dIvoire. Methods: In order to compile a list of alien and invasive plants in Cote dIvoire, published books and articles as well as national, regional and international online databases were consulted. Alien species were classified into cultivated and naturalized species. The naturalized species were further subdivided into proven invasives, potential invasives, plants to watch and plants without status in Cote dIvoire. For the list of proven invasive plants, the 4 stages of the different stages in the invasion process were applied. Finally, the proven invasive plants were classified taking into account the major and minor impacts on the environment. Key Results: The Ivorian flora includes 851 introduced or exotic species distributed in 524 genera and 137 families. These taxa are divided into 127 cultivated species and 724 naturalized species. Of all the naturalized taxa, 28 species are proven invasive plants or invasives, 34 are potential invasives, 283 are plants to be monitored and 379 are without status. The classification of the 28 proven invasive plants is divided into : 4 plants with massive impacts (MA), 10 plants with major impacts (MR), 6 plants with moderate impacts (MO) and 8 plants with minor impacts (MI). Conclusion: This study proposes a list of alien and invasive plants in Cote dIvoire. It also proposes a classification for proven invasive alien taxa according to their environmental impacts. It could constitute an important database on exotic, naturalized, proven invasive, potential invasive plants and plants to be monitored in Cote dIvoire. Biodiversity managers could thus rely on this work to establish effective strategies to control invasive plants in Cote dIvoire.

The more microplastic types pollute the soil, the stronger the growth suppression of invasive alien and native plants

Abstract The ecological consequences of microplastic pollution for plants remain largely unknown, and the few studies that tested the effects usually focused on a single type of microplastic and a single plant species. However, most plants will be exposed to multiple microplastic types simultaneously, and the effects may vary among species. To test the effects of microplastic diversity on plants, we grew single plants of eight invasive and eight native species in pots with substrate polluted with 0, 1, 3 and 6 types of microplastics. We found that the growth suppression by microplastic pollution became stronger with the number of microplastic types the plants were exposed to. This tended to be particularly the case for invasive species, as their biomass advantage over natives diminished with the number of microplastic types. The biomass responses coincided with a positive effect of the number of microplastic types on root allocation and thickness, which was also stronger for invasive than for native species. In addition, the results of hierarchical diversity–interaction models suggest that the negative impact of microplastic diversity on the total biomass of invasive plant species was influenced by both the identities of the microplastic and certain types of microplastic with strong pairwise interactions. In contrast, the effect on native species was determined solely by the microplastic identities. Synthesis. Our multispecies study thus shows for the first time that the negative effects of microplastic pollution on plant growth increase with the number of microplastic types. We also found tentative evidence that the negative impacts of microplastic diversity were more pronounced for invasive plants compared to native plants, and that this might be due to differences in the responses of root allocation and thickness.

A global meta-analysis reveals the positive effect of invasive alien plants on soil heterotrophic respiration

Plant invasions represent a major global change in the carbon cycle. Soil respiration (Rs) comprises autotrophic respiration (Ra) and heterotrophic respiration (Rh). Understanding the impacts of plant invasions on different components of soil respiration is critical for predicting how invasive alien plants (IAPs) affect the exchange of C between the atmosphere and terrestrial ecosystems. However, the responses of Rs, Rh and Ra to IAPs are poorly understood on a global scale. We conducted a meta-analysis based on 54 published papers and 256 observations to explore the effects of IAPs on Rs, Rh and Ra. Overall, the results showed that at the global scale, IAPs significantly increased the Rh by an average of 87.91% but had no significant effects on Rs or Ra. Regarding the life forms, we found that invasive forbs significantly increased Rh regardless of ecosystem type, and the subgroup analysis of ecosystem types showed that invasive forbs significantly increased Rh only in grasslands. However, the effects of IAPs on soil Rs and Rh did not differ among ecosystem types. Soil respiration is substantially influenced by soil biotic and abiotic properties. We found IAPs significantly increased microbial biomass carbon (MBC) by 9.28% (mainly from invasive forbs) and soil β-glucosidase activity by 80.35% (mainly from invasive shrubs), but the IAPs had no significant effect on invertase activity. The effect size of Rh was significantly positively correlated with the changes in soil pH, MBC and β-glucosidase. In addition, the response of Rh differed depending on the ecosystem management approach. IAPs significantly increased the Rh in abandoned ecosystems but had no significant effects on the Rh in managed ecosystems or natural ecosystems. These results emphasize the importance and complexity of the relationship between IAPs and soil respiration and highlight the need for better management to reduce soil respiration due to plant invasion.

Review of Invasive Plant Functional Traits and Management Using Remote Sensing in Sub-Saharan Africa

Biodiversity and sustainable development in Sub-Saharan Africa (SSA) are considerably impacted by invasive alien plants (IAPs). Increasing plant invasions in SSA threaten agricultural productivity, biodiversity conservation, and other socioeconomic activities, which in turn put the United Nations Sustainable Development Goals (SDGs) in peril. In order to effectively combat IAPs, understanding their functional traits (morphological, physiological, and phenological traits) and integrating them into remote sensing (RS) is vital. While functional traits influence IAPs’ fitness to invade and establish in a new geographical range, RS aids in studying them remotely, delineating and mapping them, and predicting their potential invasions. The information on this study topic was gathered by reviewing various existing studies published between 2000 and 2024. Based on this review, it was deduced that the majority of IAPs are fast-growing (or acquisitive), with a shorter leaf lifespan, bigger leaves, and higher plant height, ultimately resulting in a higher resource acquisition ability. We established further that in SSA, there are limited studies on IAP functional traits and their integration in RS. Many studies conducted in the region focus mostly on IAP distribution. Evidence from prior studies revealed that functional trait remote sensing (FTRS)-based research not only improves detection and mapping but also predicts whether a certain alien plant can become invasive or expand its distribution range. Thus, using the FTRS approach could help IAP management in SSA, ultimately achieving the SDGs. Our review discusses IAP implications in SSA (e.g., Angola, Tanzania, Benin, Kenya, Uganda, Rwanda, Zambia, Burundi, Zimbabwe, Botswana, Malawi, etc.) and for the achievement of SDGs; functional traits and their impact on alien invasions; and the importance of incorporating functional traits into RS.

High variability and multiple trade‐offs in reproduction and growth of the invasive grass Cortaderia selloana after cutting

AbstractThe ability to balance the allocation of resources between growth and reproduction as a response to stress factors, can be an advantage for plants in disturbed environments. Invasive alien plants (IAPs) often show high levels of phenotypic variability in resource allocation, a key trait that plays a crucial role in their success to invade new areas. Control management for IAPs must consider this capacity in the development of effective strategies. In this study, we performed continuous measures of leaf growth and reproductive traits of Cortaderia selloana, an IAP of global concern, and applied generalised linear models (GLMs) to evaluate trade‐offs between vegetative growth, leaf composition and reproductive success at different cutting moments. Cutting moment, but not flowering, affected the length of the vegetative growth period (VGP) and average growth rate (AGR), and the interaction with flowering affected AGR and final leaf length (vegetative growth total, VGT). Specific leaf area (SLA), leaf nitrogen (N) content and the isotopic value of δ13C were affected by cutting, and N was also affected by flowering and the interaction with cutting time. Silica also showed a negative correlation with leaf carbon (C) depicting a trade‐off between both structural components. Cortaderia selloana successfully adapted its leaf growth and composition to cutting moment, but this was also modulated by flowering. Moreover, the species is dioecious, and its response may differ between female and hermaphroditic plants. This suggests flexible trade‐offs in resource allocation, therefore the time for cutting must be precisely scheduled to suppress flowering.

Prosopis juliflora (Swartz) DC. invasion in protected areas of India under climate change

Globally invasive alien plants pose a serious threat to biodiversity and are invading protected areas. However, information regarding the potential risk of invasive alien species in protected areas is very limited in India. Therefore, the aim of the study was to examine the potential risks of P. juliflora invasions under projected climate change. We used P. juliflora climate suitability maps based on our previous study using the MaxEnt species distribution model and investigated how P. juliflora invasion may change inside and outside the protected areas by 2050 under two climate change scenarios, representative concentration pathways (RCP) 2.6 and 8.5. The findings of the study suggest that the overall area of P. juliflora suitability in the protected areas will increase by 2050. Further, we found that several protected areas containing relatively high vertebrate diversity are located in climatically suitable areas for P. juliflora. The study findings encourage management efforts to manage the spread of P. juliflora invasion in the selected protected areas of India to protect and conserve the threatened vertebrates' habitats.

Modeling population dynamics of invasive pines to optimize their control in native grasslands of Argentina

The spread of invasive alien species over natural environments has become one of the most serious threats to biodiversity and the functioning of ecosystems worldwide. Understanding the population attributes that allow a given species to become invasive is crucial for improving prevention and control interventions. Pampas grasslands are particularly sensitive to the invasion of exotic woody plants. In particular, the Ventania Mountains undergo the advance of alien woody plants; among which the Aleppo pine (Pinus halepensis) stands out due to the extension of the area it covers and the magnitude of the ecological changes associated to its presence. Using a model that describes the population dynamics of the species in the area, we evaluated the expected behavior of the population under different environmental conditions and different management scenarios. When the effect of stochastic fires was simulated, the growth rate was greater than 1 for all the frequencies considered, peaking under fires every nine years, on average. When evaluating the effect of periodic mechanical control of the adult population, the reduction in growth rate was insufficient, except for cutting intensities that significantly exceeded the current operational capacity of the area. Under prescribed fire scenarios, on the other hand, burning frequencies greater than seven years resulted in population reductions. The results highlight the importance of fire in regulating the population of P. halepensis in the Ventania Mountains, with contrasting effects depending on the frequency with which it occurs, which allows considering it as an effective environmental management option for the control of the species.

New floristic records in Kyiv City and its environs

The results of floristic research in the territory of Kyiv City and its environs (in the adjacent territories of Kyiv Region) are presented. According to the results, five new taxa for the flora of Ukraine are reported: Cardamine occulta, Equisetum × moorei, Lolium × holmbergii, Limonium sinuatum, Lonicera maackii. Chrozophora tinctoria is a new species for the flora of the mainland part of Ukraine. Also, 16 new taxa were identified for the regional floras of the Ukrainian Polissya, Forest-Steppe, and Middle Dnipro regions. In addition, new locations of 69 rare aboriginal and expansive alien taxa are reported. In total, among the studied taxa 38 are native and 53 are alien. Among the studied alien plants, several are potentially invasive ones, and some of them have already demonstrated their invasive nature, in particular: Cornus sanguinea subsp. australis, Erigeron strigosus, Phragmites altissimus, and Vitis riparia. The results of our study confirm that the flora of Kyiv City and its environs is one of the richest floras in the plain part of Ukraine, and currently it is rapidly changing.

Fungal endophytes can modulate plant invasion.

Symbiotic organisms may contribute to a host plant's success or failure to grow, its ability to maintain viable populations, and potentially, its probability of establishment and spread outside its native range. Intercellular and intracellular microbial symbionts that are asymptomatic in their plant host during some or all of their life cycle - endophytes - can form mutualistic, commensal, or pathogenic relationships, and sometimes novel associations with alien plants. Fungal endophytes are likely the most common endosymbiont infecting plants, with life-history, morphological, physiological, and plant-symbiotic traits that are distinct from other endophytic guilds. Here, we review the community dynamics of fungal endophytes during the process of plant invasion, and how their functional role may shift during the different stages of invasion: transport, introduction (colonisation), establishment, and spread. Each invasion stage presents distinct ecological filters that an alien plant must overcome to advance to the subsequent stage of invasion. Endophytes can alternately aid the host in overcoming stage-specific filters, or contribute to the barriers imposed by filters (e.g. biotic resistance), thereby affecting invasion pathways. A few fungi can be transported as seed endophytes from their native range and be vertically transmitted to future generations in the non-native range, especially in graminoids. In other plant groups, alien plants mostly acquire endophytes via horizontal transmission from the invaded plant community, and the host endophyte community is shaped by host filtering and biogeographic factors (e.g. dispersal limitation, environmental filtering). Endophytes infecting alien plants (both those transported with their host and those accumulated in the non-native range) may influence invasion success by affecting plant growth, reproduction, environmental tolerance, and pathogen and herbivory defences; however, the direction and magnitude of these effects can be contingent upon the host identity, life stage, ecological conditions, and invasion stage. This context dependence may cause endophytic fungi to shift to a non-endophytic (e.g. pathogenic) functional life stage in the same or different hosts, which can modify alien-native plant community dynamics. We conclude by identifying paths in which alien hosts can exploit the context dependency of endophyte function in novel abiotic and biotic conditions and at the different stages of invasion.

Assessing beach litter trapping efficiency in Mediterranean sandy coasts: A comparative study between typical and invaded embryonic dunes

Beach litter is one of the most evident indicators of marine litter pollution, an anthropogenic component that can affect and interact with the habitat of coastal dunes. In this study, we aim to assess the role of the Mediterranean embryonic dunes in trapping beach litter. Moreover, we investigate if dunes with native vegetation and those invaded by the alien plant C. acinaciformis differ in the trapping of beach litter. To this end, two samplings were carried out in the Tavolara-Punta Coda Cavallo Marine Protected Area, considering four beaches with different morphologies, using a paired sampling method that considers plots in the embryonic dunes and in the same habitat with C. acinaciformis. Our results indicate that plastic is the primary type of beach litter and that its distribution varied across the different beaches; especially, the greatest amount was found on pocket beaches. Based on our results, we can conclude that there are no differences between embryonic dunes with native vegetation and their invaded form, but the different beach morphologies may play a role in the distribution of beach litter. These findings may support habitat conservation initiatives such as the eradication of C. acinaciformis since it has no additional role in trapping beach litter.