Non-native Plant Research Articles

Non-native plants invasions public parks, friends or foe?

AbstractNon-native plants (NNPs) are known as alien species, which are brought outside of their natural habitats due to human activity and have an impact on the biodiversity of native plants (NPs). Because parks serve as havens for NNPs, they may pose a threat to them. The present study documented the NNPs conserved in the parks distributed in Cairo and the new settlements surrounding it. Thirty field visits were conducted from spring 2022 to Spring 2023 in 19 parks distributed in the study area. In each park NNPs were recorded. Native range, natural habitats and national geographical distribution, ethnobotanical uses, threats, and human risks were determined for NNPs. The results indicated that 37 wild NNPs belonged to 18 families were recorded in the surveyed gardens. Six species belonged to Tropical America, and other six species belonged to Mediterranean region. All recorded species were distributed in the Nile region. Thirty-six species used as medicinal plants and 31 species for human food. All recorded NNPs were exposed to one or several types of threats in their natural habitats, while 10 species were found to have a toxic effect on humans. Our results showed that the Egyptian botanic and public gardens could play an important role in the future as a source of NNPs that could be used for their contributions to ecosystem functioning and services. Also provides evidence for the essential role of public gardens in the Egyptian Nile Region for plant diversity conservation, as helps conserve wild species from other geographical regions.

Prioritizing weeds for biological control development in the western USA: Results from the adaptation of the biological control target selection system

Nonnative invasive plants (weeds) negatively impact native ecosystems, and their effects are likely to increase with continuing global trade. Biological weed control has been employed as a cost-effective and sustainable management option for weeds in the USA since 1902. Biological control programs require careful prioritization of target weeds to ensure the most appropriate targets are selected to obtain the greatest beneficial outcomes with available resources. The Biological Control Target Selection (BCTS) system was developed by researchers in South Africa as an objective, transparent approach to prioritizing new weed biological control targets. The BCTS system was recently modified and applied to 295 state-regulated weeds in the western USA for which no biological control agents have yet been released. This paper presents the results of that application, identifying the most suitable candidates for new biological control programs as well as problematic weeds for which the likelihood of successful biological control is low.Top-ranked species in the western USA are biennial or perennial weeds that occur in stable habitats, are established in more than one state, have traits deemed difficult to control with conventional methods, have large negative impacts and no conflicts of interest outside of the horticultural industry, and have substantial information available on potential biocontrol agents. Fifteen of the 20 top-ranked species are already targets of ongoing biological control programs in the USA. When species with current programs are excluded from the analysis, the next 20 top-ranked species largely differ by having less information available on potential biological control agents and having native or economically important congeners in the USA. Results from this framework provide valuable insights to the prioritization of current and future biocontrol research programs in the western USA.

Changing dominance of invasive Phragmites australis and native plant colonization with variation in management, wildfires, and soils in a desert wetland

Abstract Among the most widely distributed species globally, common reed (Phragmites australis (Cav.) Trin. ex Steud.) has generated extensive interest in invasive plant science and management because its introduced strains are highly invasive and often form monocultures that alter ecosystem properties. In desert wetlands in Las Vegas, Nevada, USA, where management goals included reducing hazardous P. australis fuels and increasing native plant diversity, we assessed variation in P. australis cover, the degree of native plant colonization, and soil seed banks after P. australis management treatments (cutting, glyphosate-imazapyr herbicide) and wildfires across gradients in soil properties. Based on change in P. australis cover during six measurement events over 24 months, 24 study sites formed three groups: 1) decreasing cover, where initially high P. australis cover (60-85%) decreased to < 5% following multiple cutting or herbicide treatments; 2) sustaining low cover, where wildfire or clearing was associated with initially low P. australis cover which remained low (< 30%) after multiple herbicide applications; and 3) sustaining high cover (45-100% initially and remaining 30-100%), including sites unmanaged or treated/burned only once. High soil salinity correlated with low post-management P. australis cover. No native plants were detected in the sustaining high P. australis cover group, despite natives occurring in the seed bank. Where management reduced P. australis cover, minimal native plant colonization did occur. Secondary invasion by other non-native plants was nearly absent. Our results suggest that if P. australis can be initially cleared, multiple herbicide applications can persistently keep cover low, especially on drier, saline soils. Slow native plant colonization suggests that a phased approach may be useful to initially reduce P. australis cover, keep it low via repeated treatments, and actively revegetate sites with native species tailored to the moisture-salinity gradient across P. australis-invaded habitats.

Distribution Patterns of Urban Spontaneous Vegetation Diversity and Their Response to Habitat Heterogeneity: A Case Study of Five Cities in Heilongjiang Province, China

Spontaneous vegetation is an important component of urban biodiversity and an excellent agent for exploring the mutual feedback mechanism between urbanization and urban ecosystems. Rapid urbanization has had a significant impact on the composition, structure, and distribution patterns of urban spontaneous vegetation diversity. Studying the diversity distribution patterns and causes of urban plant communities is beneficial for understanding the formation and maintenance mechanisms of plant diversity in specific urban habitats. This study selected five cities in different climate subregions of Heilongjiang Province as research targets and conducted field research using uniform sampling and typical sampling methods. The composition, distribution pattern, and driving factors of spontaneous vegetation were analyzed. The results showed the following: (1) A total of 633 examples of spontaneous vegetation were recorded, belonging to 93 families and 341 genera, mainly consisting of herbaceous plants and native plants. (2) The diversity index and similarity index of spontaneous vegetation in gravel-type abandoned land habitats are higher than those in other habitat types, while the diversity index of spontaneous vegetation in trees and shrubs is lower, and there is no significant difference in regards to different habitats. (3) Urban population density is a key factor affecting the diversity of native plants, while woody plant coverage, patch area, and landscape trait index are key factors affecting non-native plants. (4) The results of canonical correspondence analysis (CCA) showed that the total explanatory power of environmental characteristic factors in regards to the distribution pattern of spontaneous vegetation was 7.5%. The closest distance between adjacent patches, the coverage of woody plants in patches, the distance from the city edge, the patch area, and the surface impermeability of the buffer zones were key factors affecting the distribution of dominant species in spontaneous vegetation communities. The research results will provide an important reference for the conservation of urban biodiversity and the construction of low-maintenance urban green space plant landscapes in Heilongjiang Province.

Road corridors vegetation in the semi-arid region: functional trait diversity and dynamics

Road corridor vegetation plays a vital role in maintaining ecosystem stability and providing essential ecological services, particularly in semi-arid regions where environmental conditions are challenging. In this study, we investigated the functional traits of native and non-native plant species along the N5 highway corridor in the semi-arid region of Punjab, Pakistan. The methodology involved extensive field surveys and systematic sampling of herbaceous vegetation, followed by detailed measurements of functional traits diversity. We classified 38 plant species into native and non-native categories and analyzed their distribution, life forms, leaf spectra, and flowering phenology. Our results revealed distinct patterns in the functional traits of native and non-native species, with non-native species exhibiting larger plant heights, leaf sizes, and leaf surface areas compared to native species. Additionally, native species displayed greater root and stem biomass, indicative of adaptations to nutrient-poor soils and water-limited environments. The findings suggest that non-native species possess traits associated with rapid growth and resource acquisition, enabling them to outcompete native vegetation and establish dominance in roadside ecosystems. These results provide valuable insights for understanding the ecological implications of non-native species and designing effective management strategies to mitigate their impacts on native biodiversity and ecosystem resilience in semi-arid regions.

Global proliferation of nonnative plants is a major driver of insect invasions

Abstract Invasions by nonnative insect species can massively disrupt ecological processes, often leading to serious economic impacts. Previous work has identified propagule pressure as important driver of the trend of increasing numbers of insect invasions worldwide. In the present article, we propose an alternative hypothesis—that insect invasions are being driven by the proliferation of nonnative plants, which create niches for insect specialists and facilitate their establishment outside their native ranges where their hosts are planted or are invasive. We synthesize mechanisms by which plant invasions facilitate insect invasions, macroecological patterns supporting the tight link between plant and insect invasions, and case studies of plant invasions having facilitated subsequent insect establishment. This body of evidence indicates that plant invasions are a major driver of insect invasions. Consequently, the benefits of limiting the spread of nonnative plants include averting the proliferation of nonnative insects and their spillover onto native plant species.

Alien aquatic plants in Poland: Temporal and spatial distribution patterns and the effects of climate change

Distribution of alien aquatic plants in European freshwater ecosystems is still not fully recognized. Little is also known about the impact of climatic factors on the expansion of particular neophyte species in freshwater ecosystems. In this article, we present the first comprehensive assessment of the occurrence of non-native aquatic vascular plants in Poland (CE Europe), with a particular focus on: (1) inventory of the species, (2) temporal and spatial changes in their distribution, and (3) the climate impact on species occurrence and diversity. For this purpose, we collected both published and unpublished data on alien macrophytes occurrence in Poland covering past 70 years. In order to investigate the mechanism of alien aquatic plant expansion, climate data from 24 meteorological stations were analyzed. Redundancy analysis (RDA) was used to analyze the relationship between species composition and microclimate variables. In addition, Generalized Additive Model (GAM) was used to examine the response curves of neophyte species to temperature parameters.In total, we found records of 15 neophytes of alien aquatic plant taxa in Poland, including 14 species and collective taxon of Nymphaea cultivars. The most frequent was Elodea canadensis (over 25,000 records). Excluding this species, we counted more than 300 records of the occurrence of alien aquatic plants, of which three (E. nuttallii, Azolla filiculoides and Lemna turionifera) were the most abundant. Ten species occurred only in isolated sites. In addition, analyses showed a substantial increase in the number of the aquatic neophyte sites in the last 20 years that could be linked with the raised average monthly and yearly air temperatures in Poland.Our results showed a strong relationship between raised average temperatures in Poland and the spread of some species, e.g. Azolla filiculoides, while other species such as Elodea nuttallii and Lemna turionifera expanded irrespectively of this factor. The occurrence of some species (e.g. Vallisneria spiralis, Hygrophila polysperma) was exclusively associated to high thermally altered or thermally contaminated waters, and thus was limited to only a small part of the country. Our results confirm the major role of elevated temperatures (mean annual temperatures and minimum monthly temperatures) and thermally polluted freshwater ecosystems in the distribution of alien aquatic plants.

Phenology mediates direct and indirect interactions among co-occurring invasive plant species.

Why nonnative invasive plant species commonly co-occur, despite their competitive superiority and propensity to displace native species, remains a paradox in invasion biology. Negative interactions among competitively dominant invaders are potentially alleviated by two understudied mechanisms: seasonal priority effects, where phenological separation weakens the effect of competition on species with early phenology; and indirect facilitation, where competition between two species is mitigated by a third species. Although phenological separation has been speculated as a mechanism for explaining co-occurrence patterns of invasive plants, it has never been directly tested. In a greenhouse experiment, we tested the effect of phenological separation on direct and indirect interactions between three co-occurring invasive plant species found in the riparian forests of North America. These species have distinct natural phenological separation with reproduction in early spring (Ficaria verna), mid-spring (Alliaria petiolata), and late summer (Microstegium vimineum). When phenology was experimentally synchronized, direct pairwise interactions among invasive species were overwhelmingly negative, asymmetric, and unlikely to promote co-occurrence. However, increasing phenological separation generated seasonal priority effects, which weakened the effect of competition on species with early phenology. Furthermore, the addition of a third species generated indirect facilitative effects, which balanced competitive outcomes among the two weakest competitors. Based on these findings, we conclude that phenological separation modulates the strength of both seasonal priority effects and indirect facilitation within species interaction networks and may promote the co-occurrence of three common invasive species within this study system. We articulate how future studies can test the external validity of these findings in more complex environmental conditions and with a larger range of invasive plants.

Evaluation of Plant Growth and Flowering Performance of Florida Native and Non-native Ornamentals under Varying Irrigation

Pollinator gardening has gained momentum with an increased consumer interest in selecting native rather than non-native plant species to reduce water dependence and maximize the biodiversity value in both public greenspaces and residential gardens. Native plant species can enhance biological control and benefit ecosystems and wildlife. Often, they are also better-adapted to local environmental conditions, including temperature and rainfall, thus increasing their survival and reducing associated maintenance costs, primarily by requiring less water. Commercially available pollinator-friendly plant mixes often include both native and non-native species. A 2-year study was conducted to determine the main effects of plant provenance (native or non-native) and irrigation (full or partial irrigation) on landscape performance and flowering of 20 plants, including 10 congeneric pairs of native and non-native taxa that were planted in two locations (north and northcentral Florida). Native and non-native taxa were paired by genus to analyze the effect of the plant native status on vegetative and floral traits while controlling for variations in leaf and floral morphologies, growth habits, and blooming periods, which was a key and novel component of our study design. Represented native species included Spanish needles (Bidens alba), false rosemary (Conradina grandiflora), tickseed coreopsis (Coreopsis leavenworthii), blanket-flower (Gaillardia pulchella), swamp rosemallow (Hibiscus grandiflorus), inkberry (Ilex glabra), spotted beebalm (Monarda punctata), azure blue sage (Salvia azurea), Florida scrub skullcap (Scutellaria arenicola), and Walter's viburnum (Viburnum obovatum). Non-native taxa paired with native congeners included Beedance® painted red bidens (Bidens ferulifolia) or Goldilocks Rocks® bidens (Bidens ferulifolia ‘BID 16101’), barbeque rosemary (Salvia rosmarinus ‘Barbeque’), Jethro Tull coreopsis (Coreopsis × ‘Jethro Tull’), Arizona sun blanket-flower (Gaillardia ×grandiflora ‘Arizona Sun’), Ruffled Satin® rose of Sharon (Hibiscus syriacus ‘SHIMCR1’), dwarf Burford holly (Ilex cornuta ‘Dwarf Burford’), pardon my pink beebalm (Monarda didyma ‘Pardon My Pink’), big blue salvia (Salvia longispicata × S. farinacea ‘PAS1246577’), Malaysian skullcap (Scutellaria javanica), and Sandankwa viburnum (Viburnum suspensum). Overall, the results revealed that native plants outperformed non-native plants and exhibited greater survival, more vegetative growth, and greater floral abundance regardless of the irrigation treatment. Although there was no overall effect of irrigation on plant size or flower abundance, there were some species-specific responses, especially during the establishment year, and plants under full irrigation had greater survival in the establishment year. Thus, in general, the effects of plant provenance were stronger and more consistent across years than irrigation. Additional studies are underway to determine the floral rewards of these species and their attraction to diverse pollinators.

Native and non-native succulent plants in Algeria

Native and non-native succulent plants in Algeria

Effects of the control of an invasive tree on the structure of a plant-frugivore network.

Invasive non-native species are one of the main causes of degradation of ecosystems worldwide. The control of invasive species is key to reducing threats to ecosystem viability in the long term. Observations of structural changes in ecological interaction networks following invasive species suppression can be useful to monitor the success of ecological restoration initiatives. We evaluated the structure of plant-bird frugivory interaction networks in a plant community invaded by the guava tree (Psidium guajava L.) by comparing network metrics before and after control actions. Psidium guajava was relevant in all metrics for the unmanaged network in this study, with high degree centrality and high nestedness contribution. Based on the asymmetry of species interactions, we found that birds were highly dependent on the invasive plant before suppression. Once P. guajava trees were eliminated, bird and plant species richness, total number of interactions, and modularity increased, whereas nestedness and interaction strength asymmetry decreased. The diet of the bird community became more diversified once P. guajava was no longer available and relevant species roles in community structure emerged. Our results corroborate the fact that ecological restoration interventions should include the control of non-native plant species that attract frugivorous animals in order to diversify plant-frugivore interactions and thus maintain biodiversity in natural ecosystems.

Response of Native and Non-Native Subarctic Plant Species to Continuous Illumination by Natural and Artificial Light.

This study addressed the following questions: How does continuous lighting (CL) impact plant physiology, and photosynthetic and stress responses? Does the impact of CL depend on the source of the light and other environmental factors (natural vs. artificial)? Do responses to CL differ for native and non-native plant species in the subarctic region and, if differences exist, what physiological reasons might they be associated with them? Experiments were conducted with three plants native to the subarctic region (Geranium sylvaticum L., Geum rivale L., Potentilla erecta (L.) Raeusch.) and three non-native plant species (Geranium himalayense Klotzsch, Geum coccineum Sibth. and Sm., Potentilla atrosanguinea Loddiges ex D. Don) introduced in the Polar-Alpine Botanic Garden (KPABG, 67°38' N). The experimental groups included three species pairs exposed to (1) a natural 16 h photoperiod, (2) natural CL, (3) an artificial 16 h photoperiod and (4) artificial CL. In the natural environment, measurements of physiological and biochemical parameters were carried out at the peak of the polar day (at the end of June), when the plants were illuminated continuously, and in the second week of August, when the day length was about 16 h. Th experiments with artificial lighting were conducted in climate chambers where plants were exposed to 16 h or 24 h photoperiods for two weeks. Other parameters (light intensity, spectrum composition, temperature and air humidity) were held constant. The obtained results have shown that plants lack specific mechanisms of tolerance to CL. The protective responses are non-specific and induced by developing photo-oxidative stress. In climate chambers, under constant environmental conditions artificial CL causes leaf injuries due to oxidative stress, the main cause of which is circadian asynchrony. In nature, plants are not photodamaged during the polar day, as endogenous rhythms are maintained due to daily fluctuations of several environmental factors (light intensity, spectral distribution, temperature and air humidity). The obtained data show that among possible non-specific protective mechanisms, plants use flavonoids to neutralize the excess ROS generated under CL. In local subarctic plants, their photoprotective role is significantly higher than in non-native introduced plant species.

Plant native: comparing biodiversity benefits, ecosystem services provisioning, and plant performance of native and non-native plants in urban horticulture

AbstractPlant species used in urban horticulture are frequently non-native despite evidence that urban areas are regular points of introduction, often leading to invasions and negative impacts on biodiversity. Many horticulturalists assert that non-native plants are more successful and provide equal or greater habitat and ecosystem services than native plants. However, little research has compared native and non-native plants in urban systems. We present here a systematic literature review, using the PRISMA methodology, to assess three questions: (1) Is there a difference between native and non-native plants in their ability to support faunal biodiversity in urban green spaces? (2) Is there a difference between native and non-native plants in their provisioning of urban ecosystem services? 3)Do non-native species outperform natives in urban environments in terms of survival, growth, and fitness? We extracted data from 165 total papers. One hundred and twenty studies found that native plants outperform non-native plants on the response metric evaluated in the study, 57 demonstrated mixed impacts, 56 demonstrated no differences among plant origin, and 26 found non-native plants outperformed native plants. We found overwhelming evidence that native plants support higher faunal abundance and diversity than non-native plants in urban landscapes. Relatively few studies examined ecosystem services and plant performance, but we found that native plants support higher levels and diversity of ecosystem services and that many native plants can be used for horticulture, that is, they will survive and thrive in urban conditions. Native plants provide multiple ecosystem functions in urban greenspaces, supporting urban biodiversity and provisioning ecosystem services than non-native plant species and should be prioritized in urban horticulture activities.

Modeling the Effects of Temperature and Limiting Nutrients on the Competition of an Invasive Floating Plant, Pontederia crassipes, with Submersed Vegetation in a Shallow Lake.

The potential for a non-native plant species to invade a new habitat depends on broadscale factors such as climate, local factors such as nutrient availability, and the biotic community of the habitat into which the plant species is introduced. We developed a spatially explicit model to assess the risk of expansion of a floating invasive aquatic plant species (FAV), the water hyacinth (Pontederia crassipes), an invader in the United States, beyond its present range. Our model used known data on growth rates and competition with a native submersed aquatic macrophyte (SAV). In particular, the model simulated an invasion into a habitat with a mean annual temperature different from its own growth optimum, in which we also simulated seasonal fluctuations in temperature. Twenty different nutrient concentrations and eight different temperature scenarios, with different mean annual amplitudes of seasonal temperature variation around the mean of the invaded habitat, were simulated. In each case, the ability of the water hyacinth to invade and either exclude or coexist with the native vegetation was determined. As the temperature pattern was changed from tropical towards increasingly cooler temperate levels, the competitive advantage shifted from the tropical FAV to the more temperate SAV, with a wide range in which coexistence occurred. High nutrient concentrations allowed the coexistence of FAV, even at cooler annual temperatures. But even at the highest nutrient concentrations in the model, the FAV was unlikely to persist under the current climates of latitudes in the Southeastern United States above that of Northern Alabama. This result may have some implications for where control efforts need to be concentrated.

Messaging effects and psychological drivers for conservation behaviors at Mt. Fuji, Japan

This study demonstrated the differences in behavioral changes caused by two conservation messages through field experiments in Mount Fuji, Japan. The target behavior was to use a cleaning mat set up on a mountain trail to remove non-native plant seeds from the soles of visitors' shoes. To further understand the drivers of behavioral change, a questionnaire survey was used to examine the influence of different conservation messages and psychological and personal factors, including awe, attitudes, and norms. Knowledge linked to behavior and a sense of perceived behavioral control promoted behavior, whereas positive attitudes toward behavior and higher awe negatively impact behavior. Conservation messages interact with norms, and effective message-promoting behaviors differ depending on the norm level. Conservation messages should be selected based on the characteristics of the target segment. Even short conservation messages such as signboards can enhance the effectiveness of behavioral change, and it is valuable to think strategically about message content.

Nutritional position of managed honey bees during pollination of native plants by the melissopalynology method

Pollination services are crucial for maintaining ecological stability and ensuring food security for humans. Managed honey bees, which are economically valuable and are experiencing population growth due to the increasing demand for their products, play a significant role in pollination. To produce high-quality honey, beekeepers often choose natural high meadows, characterized by high plant species richness, for their apiaries. This practice, in turn, may contribute to the pollination of native plants, as managed honey bees are likely to forage on diverse floral resources within these meadows In this study, we investigated the nutritional position of managed bees in the pollination of native plants in Iran using the melissopalynology method to determine the extent of their contribution to the pollination of native plants. Ninety-four honey samples were collected from beekeepers located in the natural pastures of two biodiversity hotspots in Iran (Zagros and Alborz). Then, plant pollens were extracted from the honey and photographed by scanning electron microscopy. In the next step, plant species were identified, and their abundance was calculated. The results showed that managed bees visited 54 plant genera, seven of which were non-native plants. Additionally, more plant species and the highest abundance of pollen were observed at altitudes ranging from 1000 to 3000 m. Therefore, beekeepers set up their hives in this altitude range to obtain high-quality honey. In general, in this study, the results of melissopalynological analysis, involving the identification of plant genera and pollen counts, revealed that managed honey bees likely contributed less than 3% to the pollination of native plant species in Iran.

Non-native plants tend to be phylogenetically distant but functionally similar to native plants under intense disturbance at the Three Gorges Reservoir Area.

Darwin's two opposing hypotheses, proposing that non-native species closely or distantly related to native species are more likely to succeed, are known as 'Darwin's Naturalization Conundrum'. Recently, invasion ecologists have sought to unravel these hypotheses. Studies that incorporate rich observational data in disturbed ecosystems that integrate phylogenetic and functional perspectives have potential to shed light on the conundrum. Using 313 invaded plant communities including 46 invasive plant species and 531 native plant species across the Three Gorges Reservoir Area in China, we aim to evaluate the coexistence mechanisms of invasive and native plants by integrating phylogenetic and functional dimensions at spatial and temporal scales. Our findings revealed that invasive plants tended to co-occur more frequently with native plant species that were phylogenetically distant but functionally similar in the reservoir riparian zone. Furthermore, our study demonstrated that the filtering of flood-dry-flood cycles played a significant role in deepening functional similarities of native communities and invasive-native species over time. Our study highlights the contrasting effects of phylogenetic relatedness and functional similarity between invasive and native species in highly flood-disturbed habitats, providing new sights into Darwin's Naturalization Conundrum.

The Spread of Invasive and Poisonous Plants: A Lesson from Alkaloids

Invasive plant species pose a significant threat to global biodiversity and ecosystems. Climate changes favor the spread of non-native plants, whether voluntary or accidentally introduced into a new environment, as these plants possess a greater ability to adapt to changing environments. The spreading of these alien species has a negative impact also on agro-ecosystems, on agricultural yields, and on the nutritional quality of food crops. The high metabolic plasticity of these plants helps them to adapt to new ecosystems, enabling them to succeed in competing with crops. In particular, many alien plants are producers of alkaloids. These molecules represent the main chemical defense to biotic stressors and also the major risk for human health. In this review, we focused on invasive plants producing tropane alkaloids (TAs) and pyrrolizidine alkaloids (PAs). We explored the potential role of these molecules in the fitness of invasive plants in the context of climate change and reviewed the knowledge regarding their biosynthesis steps and examined the mechanism of toxicity when accidentally ingested. Finally, we summarized the most efficient analytical and molecular methods to detect either alkaloid contamination or the presence of invasive plant contaminants, which are the source of these molecules, in food crops. Possible solutions and precautions to ensure food safety have been also proposed.

Native Plant Diversity Generates Microbial Legacies That Either Promote or Suppress Non-Natives, Depending on Drought History.

Diverse native plant communities resist non-native plants more than species-poor communities, in part through resource competition. The role of soil biota in diversity-invasibility relationships is poorly understood, although non-native plants interact with soil biota during invasions. We tested the responses of non-native plants to soil biota generated by different native plant diversities. We applied well-watered and drought treatments in both conditioning and response phases to explore the effects of 'historical' and 'contemporary' environmental stresses. When generated in well-watered soils, the microbial legacies from higher native diversity inhibited non-native growth in well-watered conditions. In contrast, when generated in drought-treated soils, the microbial legacies from higher native diversity facilitated non-native growth in well-watered conditions. Contemporary drought eliminated microbial legacy effects on non-native growth. We provide a new understanding of mechanisms behind diversity-invasibility relationships and demonstrate that temporal variation in environmental stress shapes relationships among native plant diversity, soil biota and non-native plants.

High resistance to non-native plant invasion exhibited in a maritime alpine environment

High resistance to non-native plant invasion exhibited in a maritime alpine environment