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The genus Ludwigia L. section Jussiaea is composed of a polyploid species complex with 2x, 4x, 6x and 10x ploidy levels, suggesting possible hybrid origins. The aim of the present study is to understand the genomic relationships among diploid and polyploid species in the section Jussiaea. Morphological and cytogenetic observations, controlled crosses, genomic in situ hybridization (GISH), and flow cytometry were used to characterize species, ploidy levels, ploidy patterns, and genomic composition across taxa. Genome sizes obtained were in agreement with the diploid, tetraploid, hexaploid, and decaploid ploidy levels. Results of GISH showed that progenitors of Ludwigia stolonifera (4x) were Ludwigia peploides subsp. montevidensis (2x) and Ludwigia helminthorrhiza (2x), which also participated for one part (2x) to the Ludwigia ascendens genome (4x). Ludwigia grandiflora subsp. hexapetala (10x) resulted from the hybridization between L. stolonifera (4x) and Ludwigia grandiflora subsp. grandiflora (6x). One progenitor of L. grandiflora subsp. grandiflora was identified as L. peploides (2x). Our results suggest the existence of several processes of hybridization, leading to polyploidy, and possibly allopolyploidy, in the section Jussiaea due to the diversity of ploidy levels. The success of GISH opens up the potential for future studies to identify other missing progenitors in Ludwigia L. as well as other taxa.

Seed dispersal by frugivorous birds facilitates plant invasions, but it is poorly known how invasive plants integrate into native communities in fragmented landscapes. We surveyed plant–frugivore interactions, including an invasive plant (Phytolacca americana), on 22 artificial land-bridge islands (fragmented forests) in the Thousand Island Lake, China. Focusing on frugivory interactions that may lead to seed dispersal, we built ecological networks of studied islands both at the local island (community) and at landscape (metacommunity) levels. On islands with P. americana, we found that P. americana impacted local avian frugivory networks more on islands with species-poor plant communities and on isolated islands. Moreover, as P. americana interacted mainly with local core birds (generalists), this indicates reduced seed dispersal of native plants on invaded islands. At the landscape level, P. americana had established strong interactions with generalist birds that largely maintain seed-dispersal functions across islands, as revealed by their topologically central roles both in the regional plant–bird trophic network and in the spatial metanetwork. This indicates that generalist frugivorous birds may have facilitated the dispersal of P. americana across islands, making P. americana well integrated into the plant–frugivore mutualistic metacommunity. Taken together, our study demonstrates that the impact of plant invasion is context-dependent and that generalist native frugivores with high dispersal potential may accelerate plant invasion in fragmented landscapes. These findings highlight the importance of taking the functional roles of animal mutualists and habitat fragmentation into account when managing plant invasions and their impact on native communities.

Human impact has extensively transformed and degraded more than two-thirds of terrestrial land, highlighting the urgent need for restoration. To improve restoration outcomes in harsh environments, there is a pressing need to develop effective and economically viable techniques. Soil microorganisms, known for their vital roles in soil nutrient cycling, soil structure stabilization, and plant-soil interactions, have gained considerable attention in academia. Nonetheless, their application in restoration projects remains limited. Many of previous attempts to incorporate soil microbial organisms into restoration were driven by the progress in understanding soil microbial functions rather than the practical demands of restoration practitioners. Additionally, the spatial heterogeneity of soil microbial communities often leads to inconsistent effects of soil microorganisms in restoration projects. To overcome two barriers above and achieve practitioner-oriented microbial methods, it is essential to anchor microbial studies locally, address unresolved issues in current restoration strategies, and validate the effect of potential functional microorganisms through field experiments.Two fundamental questions must be addressed to determine the direction for applying soil microorganisms to restoration. First, should soil microbial communities be indirectly managed through existing restoration methods, or should they be directly manipulated? Second, should soil microbial communities be monitored and used as restoration indicators or manipulated to provide specific ecosystem functions? In response to the first question, soil microbial communities from eight ongoing revegetation field experiments across the American Southwest were analyzed. Revegetation with one species and four species resulted in similar microbial community richness, composition, and relative abundance of functional groups, suggesting that direct manipulation of soil microbial communities seems more appropriate.

Eichhornia crassipes represents a situation of environmental risk in the black lagoon of Tixtla, because it is a highly invasive plant, the sowing lands in the rainy season are invaded, in the dry season, it covers the soils in which the various crops are established; the production of organic fertilizers is an alternative that allows an ecological use to be given to this problem by obtaining vermicompost. The objective was to determine the viability of this plant as a raw material to produce organic fertilizer in mixture with other residues, as well as its effect on the production of vegetable seedlings from a randomized design of 5 treatments and 4 replications with 20 experimental units at plant height 10 and 15 days after hatching. The height of plants at 15 days of birth was significantly influenced by the materials that do not contain manure in their composition, exerting an effect on the germination and growth of seedlings in the mixtures of lily with organic residues. The treatments corresponding to 50% water lily with 50% market waste, 100% water lily and the mixture of 25% lily with 25% recycled paper and leaf litter waste, have obtained the best plant heights with 13.5, 12.00 and 9.5 centimeters of plant height at 15 days after hatching, respectively. This means that as you require nutrition, organic fertilizers release these nutrients effectively., Eichhornia crassipes representa una situación de riesgo ambiental en la laguna negra de Tixtla, por ser una planta altamente invasora, los terrenos de siembra en tiempos de lluvias son invadidos, en la época de estiaje, cubre los suelos en los que se establecen los diversos cultivos; la producción de abonos orgánicos es una alternativa que permite darle un uso ecológico a este problema obteniendo lombricomposta. El objetivo fue determinar la viabilidad de esta planta como materia prima para producir abono orgánico en mezcla con otros residuos, así como su efecto en la producción de plántulas de hortalizas a partir de un diseño aleatorio de 5 tratamientos y 4 repeticiones con 20 unidades experimentales en la altura de plantas a 10 y 15 días después de nacidas. La altura de plantas a 15 días de nacida se vio significativamente influenciada con los materiales que no contienen estiércoles en su composición, ejerciendo en las mezclas de lirio con residuos orgánicos un efecto en la germinación y crecimiento de las plántulas. Los tratamientos correspondientes a 50% lirio acuático con 50% residuos de mercado, 100% lirio acuático y la mezcla de 25% lirio con 25% papel reciclado y residuos de hojarascas, han obtenido las mejores alturas de plantas con 13.5, 12.00 y 9.5 centímetros de altura de planta a 15 días después de nacida, respectivamente. Lo cual significa que a medida que requiere nutrición, los abonos orgánicos liberan dichos nutrientes de manera eficaz.

This dataset pertains to three types of plants: the apple tree (Malus pumila Mill.), and the invasive species Erigeron annuus (L.) Pers. and Erigeron canadensis L. Images of all three species were collected on-site in an apple orchard using a drone. The drone was equipped with a DJI DL 35mm F2.8 LS ASPH lens, with a sensor size of 35.9 mm by 24 mm. To preserve greater image detail and minimize background blurring, the aperture was set at f/16 during image capture. The images were taken from heights of 5m, 10m, 15m, 20m, and 25m, with corresponding Ground Sample Distances (GSD) of 0.0625 cm/pixel, 0.125 cm/pixel, 0.1875 cm/pixel, 0.25 cm/pixel, and 0.3125 cm/pixel, respectively. The dataset includes both original and data-augmented images. Data augmentation techniques employed include flipping, rotation, elastic deformation, contrast adjustment, brightness modification, sharpening changes, noise addition, blurring, and mosaicking. The images are 512×512 pixels in size.

Land-use change, and associated land clearing/conversion and fragmentation are major drivers of biodiversity decline across the globe. The spread of invasive species is a well-recognised consequence of land-use change. The extent and intensity of invasion however is often difficult to assess due to a lack of temporal data. Using detailed mapping information for 130, 950 km2 of sub-coastal Queensland, Australia and results from field surveys we investigated changes to land-use, the extent of remnant (intact) vegetation and the spread of prominent invasive plant species over time (1997–2018). In the 50 years prior to 1997 the area underwent significant land development (mostly for livestock grazing and crops), resulting in a reduction of 45% of its remnant vegetation. Despite key policy developments aimed at protecting the remaining vegetation and species, 7392 km2 was cleared/converted between 1997 and 2017, mainly for the expansion of grazing and cropping lands. Vegetation types specifically listed for national protection under these policies were some of the greatest affected, highlighting the need for improved implementation and regulation of these control measures. Within remaining fragments of remnant vegetation, the cover and presence of two invasive perennial grass species indian couch (Bothriochloa pertusa) and buffel grass (Cenchrus ciliaris) increased significantly during this time period. There was also a moderate increase in the cover and presence of the annual herb Parthenium weed (Parthenium hysterophorus). The spread of these species within the landscape likely reflects an ‘invasion debt’, incurred from an intense history of land-use within the region and we predict this trend will continue to threaten remnant ecosystems.

Plant phenology, i. e. the timing of life cycle events, is related to individual fitness and species distributionranges. Temperature is one of the most important drivers of plant phenology together with day length.The adaptation of their phenology may be important for the success of invasive plant species. The presentstudy aims at understanding how the performance and the phenology of the invasive legume Lupinuspolyphyllus vary with latitude. We sampled data across a >2000 km latitudinal gradient from Centralto Northern Europe. We quantified variation in phenology of flowering and fruiting of L. polyphyllususing >1600 digital photos of inflorescences from 220 individual plants observed weekly at 22 sites. Theday of the year at which different phenological phases were reached, increased 1.3–1.8 days per degreelatitude, whereas the growing degree days (gdd) required for these phenological phases decreased 5–16 gddper degree latitude. However, this difference disappeared, when the day length of each day included inthe calculation of gdd was considered. The day of the year of the earliest and the latest climatic zone toreach any of the three studied phenological phases differed by 23–30 days and temperature requirementsto reach these stages differed between 62 and 236 gdd. Probably, the invasion of this species will furtherincrease in the northern part of Europe over the next decades due to climate warming. For invasive speciescontrol, our results suggest that in countries with a large latitudinal extent, the mowing date should shiftby ca. one week per 500 km at sites with similar elevations.

Plant phenology, i. e. the timing of life cycle events, is related to individual fitness and species distribution ranges. Among the environmental factors, phenology is mostly driven by temperature and day length. Rapid adaptation of their phenology may also be important for the success of invasive plant species. Our main aim was to understand how the performance, timing, and temperature dependence of the phenology of the invasive legume Lupinus polyphyllus varies with latitude. L. polyphyllus is one of the most frequent invasive species in Europe, and the gained information may help to make management more effective by adjustments to latitude and phenology. Methods: We quantified variation in phenology across a >2000 km latitudinal gradient from Central to Northern Europe. We sampled data of flowering and fruiting of L. polyphyllus using >1600 digital photos of inflorescences from 220 individual plants observed weekly at 22 locations. We calculated the accumulated growing degree days for each observation date at each site from the temperature data of the meteorological stations, which are listed in the metadata of the dataset., License:This work is licensed under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication license.

Arbuscular mycorrhizal (AM) fungi can increase the tolerance of host plants to drought, whereas the intrinsic mechanisms are not still fully elucidated. Flavonoids are a kind of antioxidants to scavenge reactive oxygen species (ROS), whereas whether and how flavonoids are involved in increased drought tolerance of host plants by AM fungi is not known. Here, Funneliformis mosseae, was inoculated into potted trifoliate orange seedlings, which were subjected to adequate water and water stress conditions. The AM effect on plant growth, concentrations of flavonoid substances and total flavonoids, and activities and expression levels of enzymes related to flavonoids synthesis (clnnamate 4-dydroxylate (C4H), phenylalanine ammonialyase (PAL), chalcone isomerase (CHI), and 4-coumaroyl-CoA ligase (4CL)) in roots was analyzed, along with changes in scavenging activity of ROS by root flavonoid extracts. Compared with non-AM control, F. mosseae inoculation distinctly improved plant growth performance and increased phenylalanine, glycitin, luteolin-7-O-glucoside, and total flavonoid concentrations, coupled with the decrease in p-coumaric acid, regardless of soil water regimes. Activities of C4H, CHI, 4CL, and PAL and expression levels of PtPAL1 and Pt4CL were induced by F. mosseae inoculation under water stress. AM plants exhibited higher scavenging activity of hydroxyl radical and superoxide (O) by root flavonoid extracts under water stress, along with lower levels of O and hydrogen peroxide and the degree of membrane lipid peroxidation, compared with non-AM plants. It is concluded that AM fungi accelerated flavonoids synthesis of trifoliate orange for mitigating oxidative damage under water stress.

Water hyacinth is an aquatic free-floating plant that is highly invasive, to the extent that it is now present in most freshwater bodies in sub-tropical and tropical regions worldwide. Due to the ecological and socio-economic damages these plants can cause, monitoring their spatial coverage and seasonality is key for development of timely and efficient mitigation measures. Hyacinth patches are sufficiently large to be detectable in high-resolution satellite imagery, allowing for monitoring using freely available remote sensing data collected by platforms such as Sentinel-2. In this study, we estimated water hyacinth coverage and seasonal dynamics over three years (2018-2020) for the Saigon river, Vietnam. Using a Naïve Bayes classifier, hyacinth coverage was mapped in Sentinel-2 imagery with an accuracy of 91%. We show that the dry season (December-May) corresponds to highest water hyacinth abundance, with maximum coverage in February. Lower rainfall and relative humidity were found to be highly correlated (r = -0.56 and r = -0.64, respectively) with higher hyacinth cover. We also detected substantial interannual variability: annual means in hyacinth coverage varied by a factor of five between the 2018/2019 and 2020 yearly averages, with peak cover occurring in February 2020. The percentage of Saigon river covered by hyacinths over the entire study area peaked at 14% and reached as much as 24% for the upstream section. This confirms the prevalence of these invasive plants in the region, and the growing threat to river navigability and biodiversity. Our study provides an openly available automated workflow for long-term monitoring of hyacinth coverage, which can be scaled-up and extended to other freshwater systems. As such, it provides a step for building a large-scale monitoring tool of this highly invasive species, which may also be used for designing mitigation and reduction strategies of hyacinth and the pollutants it carries along.

This dataset provides all data used in the peer-reviewed article entitled: "Rivers running green: water hyacinth invasion monitored from space" and available at: https://iopscience.iop.org/article/10.1088/1748-9326/ac52ca. In particular, the dataset presents the time-series of hyacinth coverage retrieved from Sentinel-2 satellites over the Saigon river, Vietnam. In addition, in-situ data on organic material collected at the Saigon river, in Ho Chi Minh City in 2018 are also provided. This dataset was used to assess the robustness of the hyacinth coverage estimated from the Sentinel-2 images. Lastly, hydrometeorological variables for the years 2018 and 2019 are also included, as they were used to investigate the temporal variability in hyacinth coverage.

Acer negundo L. is recognized as an invasive deciduous tree species that tends to grow and spread out of its natural range posing a threat to the biodiversity of the impacted areas. Although invasive plant species are considered to negatively affect ecosystems, their biomass can be used for environmental benefits. In order to find abundant and inexpensive sorbent for wastewater purification and metal pollution minimization, A. negundo leaf biomass was selected and investigated for that purpose. Since lead is well known as a common pollutant occurring in various industrial effluents with harmful effects on biota, it was selected for the sorption experiments. Acer negundo L. (AN) samples were collected at the unpolluted area in Mountain Avala, Serbia. After milling and sieving, the prepared sorbent was used in batch system sorption experiments. Experiments were conducted under isothermal conditions, by adding a precise amount of sorbent in the lead solution of known initial concentration. The adsorption performance of the obtained biomass-derived material (AN) was evaluated by testing several operational parameters: initial pH value, initial sorbent dosage, contact time, and initial lead concentration. The experimental parameters were optimized in order to determine the most appropriate conditions for Pb(II) removal. Maximum lead uptake occurs at pH 5, with 2g/L of sorbent dosage. The kinetic study revealed very fast adsorption, with equilibrium occurring after an initial 15 min of contact between sorbent (A. negundo leaf biomass) and sorbate (1mmol/L of lead solution). After this contact time, the residual metal concentration started to increase indicating the desorption process. Data obtained from sorption experiments were subjected to equilibrium modeling: they were fitted by two-parameter models (Langmuir and Freundlich). Results showed that the maximal adsorption capacity of a sorbent is 109 mg/g. Obtained results suggest that Acer negundo leaf biomass can be suc

Most restoration projects involving invasive plant eradication tend to focus on plant removal with little consideration given to how these invasives change soil microbial communities. However, soil microorganisms can determine invasibility of habitats and, in turn, be altered by invasives once established, potentially inhibiting native plant establishment. We studied soil microbial communities in coastal dunes with varying invasion intensity and different restoration approaches (herbicide, mechanical excavation) at Point Reyes National Seashore. Overall, we found evidence of a strong link between bacterial and fungal soil communities and the presence of invasives and restoration approach. Heavily invaded sites were characterized by a lower abundance of putatively identified nitrifiers, fermentative bacteria, fungal parasites, and fungal dung saprotrophs and a higher abundance of cellulolytic bacteria and a class of arbuscular mycorrhizal fungi (Archaeosporomycetes). Changes in soil microbiota did not fully dissipate following removal of invasives using herbicide, with exception of reductions in cellulolytic bacteria and Archaeosporomycetes abundance. Mechanical restoration effectively removed both invasives and soil legacy effects by inverting or “flipping” rhizome-contaminated surface soils with soils from below and may have inadvertently induced other adverse effects on soils that impeded reestablishment of native dune plants. Land managers should consider additional measures to counteract lingering legacy effects and/or focus restoration efforts in areas where legacy effects are less pronounced.

Oenothera drummondii Hook. (Onagraceae) has life-history traits that make it an invasive species. Native populations are distributed along the coastal dunes from North Carolina in the United States to Tabasco in the Gulf of Mexico. It has been reported as an invasive species in Spain, Israel, and China, where this species can successfully colonize and dominate if the environmental conditions are appropriate. In South Africa, Australia, New Zealand, and France, it is reported to be naturalized. In this study, 28 microsatellite markers developed for other Oenothera species were evaluated for cross-amplification in O. drummondii. Nine primers showed consistent amplification and were polymorphic. Polymorphism was assessed in three populations from both native and invaded areas. Results indicated generalized low genetic variability. Three loci showed significant deviations from the Hardy Weinberg equilibrium, associated with null alleles’ presence. The observed heterozygosity and inbreeding coefficient reflected a generalized excess of homozygotes, particularly in the invaded population “El Dique”, likely due to allele fixation. High genetic differentiation was found between the three populations. These results highlight the accuracy of these markers for future population genetic studies in O. drummondii.

The invasive tree-of-heaven, Ailanthus altissima (Miller) Swingle, is widespread and damaging throughout North America. Verticillium wilt disease is emerging as a potentially exciting biological control option for this difficult to control tree. In Virginia, Verticillium nonalfalfae has been confirmed causing significant mortality to A. altissima, while V. dahliae is suspected to be present and causing lower levels of disease. Little else is known regarding these two fungal species in this state. The purpose of this research was to gain a better understanding of how Verticillium wilt impacts A. altissima and its potential as a biological control agent. We first confirmed V. dahliae's presence in Virginia and its pathogenicity to A. altissima using Koch's postulates. We then completed a regional field-inoculation experiment to show that V. nonalfalfae effectively kills and spreads to adjacent A. altissima, regardless of V. dahliae presence or other climate and stand variables. Additionally, we showed that V. dahliae causes lower levels of disease than V. nonalfalfae, and does not spread rapidly. Next, we surveyed all Virginia A. altissima stands known to be naturally infected with V. nonalfalfae to determine whether V. nonalfalfae persists long-term, that it considerably reduces A. altissima numbers, and that its local prevalence may be higher than initially suspected. However, we were unable to infect A. altissima seedlings using soil collected at these infested sites, suggesting that V. nonalfalfae's survival within field soil may be limited. Lastly, using paired A. altissima invaded-uninvaded sites, we found that A. altissima presence is associated with a decreased proportion of native plants and species in the woody and herbaceous understory, but not the germinable seedbank. Furthermore, we found that this impact on the woody understory appears to increase over time, supporting early management actions and helping us predict post-management restoration needs. We

We record for the first time the host association of the seed beetle Merobruchus paquetae with the invasive legume tree Leucaena leucocephala. This species of beetle was associated in Colombia to the native legume tree Pseudosamanea guachapele., Se registra por primera vez la asociación del escarabajo consumidor de semillas Merobruchus paquetae con el hospedero de leguminosa invasivo Leucaena leucocephala. Esta especie de escarabajo está asociada en Colombia con la leguminosa nativa Pseusosamanea guachapele.

A new exotic plant species to Europe, Cleome gynandra L. (Cleomaceae), has been detected in Valencia (Spain), using the ‘seed stowaway’ strategy in horticultural substrata under greenhouse conditions., Se ha detectado una nueva especie vegetal alóctona, Cleome gynandra L. (Cleomaceae), usando la estrategia de ‘polizón de semilla’ dentro de los sustratos utilizados en la producción de planta forestal en condiciones de invernadero en Valencia (España).

Aim Ecological inferences drawn from studies on niche dynamics of invasive species are often limited due to difficulties in disentangling evolutionary adaptations of the fundamental niche from demographic and interspecific processes shaping the realized niche. We used Ageratina adenophora, an invasive plant with restricted evolutionary potential to investigate shifts in the realized climatic niche independent of potential evolutionary adaptations. Location Native Mexican range; exotic ranges in Asia, the USA, the Canary Islands and Australia. Taxon Invasive Asteraceae A. adenophora (Spreng.) R.M.King & H.Rob. Commonly known as Crofton weed. Methods We compiled a robust occurrence dataset of A. adenophora for its native Mexican range and four exotic ranges (Asia, USA, Canary Islands, and Australia) and quantified pairwise niche overlap (Schoener's D) and niche dynamic (stable, unfilling and expansion) indices between the native and exotic ranges in reduced climatic space using smoothed occurrence densities. Niche shift was statistically tested using niche equivalency tests. Results The value of niche overlap (Schoener's D) differed considerably, ranging from relatively high between Mexico and Asia to low between Mexico and Australia. The niche dynamic indices indicated highest level of niche stability in Asia while highest degree of unstable niche was detected in Australia due to both niche expansion and unfilling. The niche similarity tests indicated that the native niche is more similar to the exotic niche than any randomly sampled niche from the exotic range. However, the niche equivalency tests showed evidence of niche differentiation as the observed niche overlap was lower than expected by chance for all pairwise comparisons. Jointly these tests indicate that despite the similarity, the native niche is not perfectly identical to any of the exotic niches. Main conclusions The current study has direct implications for understanding range

Increasing air temperature and atmospheric CO levels may affect the distribution of invasive species. Whereas there is wide knowledge on the effect of global change on temperate species, responses of tropical invasive species to these two global change drivers are largely unknown. We conducted a greenhouse experiment on Terminalia catappa L. (Combretaceae), an invasive tree species on Brazilian coastal areas, to evaluate the effects of increased air temperature and CO concentration on seed germination and seedling growth on the island of Santa Catarina (Florianópolis, Brazil). Seeds of the invasive tree were subjected to two temperature levels (ambient and +1.6 °C) and two CO levels (ambient and ~650 ppmv) with a factorial design. Increased temperature enhanced germination rate and shortened germination time of T. catappa seeds. It also increased plant height, number of leaves and above-ground biomass. By contrast, increased atmospheric CO concentration had no significant effects, and the interaction between temperature and CO concentration did not affect any of the measured traits. Terminalia catappa adapts to a relatively broad range of environmental conditions, being able to tolerate cooler temperatures in its invasive range. As T. catappa is native to tropical areas, global warming might favour its establishment along the coast of subtropical South America, while increased CO levels seem not to have significant effects on seed germination or seedling growth.

Hybridization is a frequent process that leads to relevant evolutionary consequences, but there is a lack of studies regarding the relationships of the variability of the response of parental plant species to environmental gradients and the responses of their hybrids at a phenotypic level. We designed an experiment in which we exposed two reciprocal cordgrass hybrids, Spartina maritima × densiflora and S. densiflora × maritima, and their parental species to four salinity concentrations for 30 days. The main objectives were to compare the performance of the hybrids with that of their parents, to distinguish the phenotypic inheritance operating in the hybrids and to analyse the relationships between the variability in the responses of the parents and the responses of their hybrids to salinity. We characterized the responses and the degree of variability for 37 foliar traits. Both hybrids presented greater salinity tolerance than their parents, showing their highest percentage of transgressive traits at both extremes of the salinity gradient. When the parental plants themselves showed a more plastic response for a given trait, there was a greater chance that their hybrid developed a transgressive behaviour for this trait. This finding supports a new focus to be applied for the artificial development of vigorous hybrid crops.

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch), Although the problem of plant invasions is expected to increase with climate change, there is as yet little experimental evidence, in particular, for the effects of extreme weather events. We established communities of European meadow species, which were subjected to warming and extreme event (drought and deluge) treatments in a factorial design at an experimental garden in Zurich, Switzerland. Phylogenetically matched pairs of native and alien species (Bromus erectus, B. inermis, Trifolium pratense, T. hybridum, Lactuca serriola, and Conyza canadensis) were introduced into the communities to test if invader performance is favored by warming and extreme events, and if alien invaders perform better than native colonizers. With a warming of on average 0.3°C, a higher cover of native plant communities was observed, while drought decreased cover in the short-term and lowered biomass. Germination, survival, and growth of the introduced species were lower under elevated temperature. Survival of all pairs and growth of Trifolium was greater in drought pots, while deluge had no effect. While the alien species showed a faster rate of increase in the number of leaves, mortality of alien species was greater than of native species. Overall, the performance of the focal species varied much more among taxonomic groups than native/alien provenances. The results suggest that with climate change, different types of extreme events will differ in the severity of their effects on native plant communities. Meanwhile, the effects of climate change on plant invasions are more likely to operate indirectly through the impacts on native vegetation.

Experimentally applying pesticides is an important method to assess the efficacy of weed biocontrol agents, but potential direct effects of the chemicals on plant performance are controversial or unknown. We assessed how three broad-spectrum insecticides applied in combination affect the performance of the widely invasive, crop-yield reducing, allergenic common ragweed (Ambrosia artemisiifolia L.) in an insect-free environment. Spraying insecticides had no significant effects on aboveground dry weight, seed and pollen output or pollen allergenicity, and only explained 1-8% of variation in these parameters. Our insecticide treatment can hence be applied to assess biocontrol impact on biomass and reproductive output of common ragweed. As our insecticide treatment delayed senescence, however, other methods of insect exclusion should be preferred when studying common ragweed phenology.

[Resumo]: As especies invasoras son das principais causas da perda de biodiversidade a escala global. Moitas das especies de plantas invasoras máis agresivas do mundo son clonais. Neste experimento estudouse a importancia dos atributos asociados ao crecemento clonal, en particular, a capacidade de integración fisiolóxica na expansión da especie invasora Carpobrotus edulis colonizando dous hábitats diferentes: duna costeira e costa rochosa. Os nosos resultados demostran a importancia da integración clonal para a expansión desta especie en termos de biomasa total e de expansión en lonxitude dos fragmentos clonais. Este beneficio da integración clonal foi independente do hábitat invadido; tanto en duna costeira coma en costa rochosa a integración fisiolóxica incrementou a capacidad de crecemento e colonización de C. edulis. O estudo dos mecanismos que subxacen nos procesos de invasións biolóxicas son fundamentais para entendelas e para propoñer medidas de erradicación e control das mesmas., [Resumen]: Las especies invasoras son de las causas principales de pérdida de biodiversidad a escala global. Muchas de las especies de plantas invasoras más agresivas son clonales. En este experimento se estudió la importancia de los atributos asociados al crecimiento clonal, en particular, la capacidad de integración fisiológica en la expansión de la especie invasora Carpobrotus edulis colonizando dos hábitats distintos: duna costera y costa rocosa. Nuestros resultados demuestran la importancia de la integración clonal para la expansión de esta especie en términos de biomasa total y de expansión en longitud de los fragmentos clonales. Este beneficio de la integración clonal fue independiente del hábitat invadido; tanto en duna costera como en costa rocosa la integración fisiológica incrementó la capacidad de crecimiento y colonización de C. edulis. El estudio de los mecanismos que subyacen en los procesos de invasión biológicas son fundamentales para entenderlas y para proponer medidas de erradicación y control de las mismas., [Abstract]: Invasive species are one of the main causes for biodiversity loss at a global scale. Many of the most aggressive invasive plant species are clonal. In this experiment we study the importance of the attributes associated with clonal growth, in particular, we aim to determine the importance of physiological integration in the expansion of the invasive species Carpobrotus edulis colonizing two different habitats: coastal dune and rocky coast. Our results demonstrate the contribution of clonal integration for the expansion of this species in terms of total biomass and growth in length of the clonal fragments. This benefit of clonal integration was not dependent of the invaded habitat; thus, both in coastal dune and the rocky coast, physiological integration increased the growth and colonization capacity of C. edulis. The study of the mechanisms underlying the processes of biological invasion are key to understand them and to design eradication and control programs.

The objective of this study was to determine whether native and invasive plants harbor different bacterial communities in their rhizospheres and whether there are bacterial indicator species associated with the invasive rhizosphere. Additionally, physico-chemical, biochemical, and biological properties have been determined in the native and invasive rhizospheres in order to ascertain the relationships between these soil properties and the rhizosphere bacterial communities. We carried out a study in five independent locations under Mediterranean semiarid conditions, where the native Hyparrhenia hirta is being displaced by Pennisetum setaceum. Partial 16S rRNA genes of the rhizosphere bacterial communities were amplified and 454-pyrosequenced. Principal coordinate analysis revealed differences in the composition and structure of the rhizosphere bacterial communities between native and invasive plants, the values of the richness index being higher in the invasive microbial community. Rhizosphere microbial community structure was also influenced by invaded location. The indicator species analysis showed a higher number of indicators for the invasive community at all the taxonomic levels studied, the genus Ohtaekwangia being the most abundant indicator. As shown by canonical correspondence analysis, the protease and dehydrogenase activities and soil respiration were related to the rhizosphere bacterial community of invasive plant. However, only protease activity was significantly affected by the plant type, being higher in the invasive plant rhizosphere. Our results show that P. setaceum invasion has produced an intense interaction with the soil bacterial community, shifting its structure, composition, and protease activity related to N cycling, which may be altering the function of the invaded ecosystem.

1. Changes to plant community composition after invasion are well documented but how these shifts directly affect higher trophic levels is still poorly understood. One potentially important factor is the change in nutritional availability after an invasion. Shifts in nutrient availability could affect the nutrient intake of organisms that live in invaded habitats, causing reduced fecundity and survival. 2. The effects of the interaction among nutrient availability, selection, and diet on nutrient intake of a native bumble bee were examined. No nutritional differences were found between exotic and native pollen or collected and non-collected pollen in protein or amino acid content, suggesting that differences in nutrient intake from random are based on selection. 3. Nutrient intake was simulated when pollen was selected randomly across all available plant species and when selection was restricted to native plants only or exotic plants only using a permutation model and compared with observed collection. The results suggest that pollen collection is non-random and that selecting only native or exotic plants cannot provide the protein or amino acid intake observed. 4. These results may help to explain why the responses of native bees to exotic plants are so variable. If the exotic plants in a community can supply the necessary nutrients, bees may readily incorporate them into their diets, but if not, exotic plants may be avoided.

Many new plant varieties that are sold for livestock pasture pose a weed risk that jeopardizes their purpose — the sustainable intensification of agriculture — by increasing the environmental costs of food production.

More than ten years ago, a biological control plan was initiated by Department of Agriculture of the United States (USDA) in order to find a solution for counteracting the invasion of the Red Giant: Arundo donax Linnaeus (1753) in riparian ecosystems of USA and México. This invasive plant is originating serious environmental and economic problems in these natural areas as the displacement of native plant species, decreasing in its associate fauna biodiversity and an important water consume. An insect complex was considered as potential biological control agents against this grass, between them, Rhizaspidiotus donacis Leonardi (1920) (Hemiptera; Diaspididae) was one of the most encouraging agents due to this insect exerts a significant impact on both, aerial and underground parts of the plant. Nowadays, the releases of this monofagous insect have been accepted and carried out along Río Grande, one of the most affected natural areas. The settlement and reproduction of R. donacis were reported with good preliminary observations about the impact of the insect in the invasive areas.

Climate change, landowner diversity, human socio-cultural and political attitudes, the biological and ecological characteristics of invasive plants and the nature of the communities they invade are the major drivers of plant invasion. The role of landowners in ranking invasive weeds and in adopting appropriate management strategies to limit invasion problems has received insufficient research attention. This thesis aimed to investigate how the complex interaction between bio-physical and socio-political drivers exacerbates the invasion problem and leads to adoption of management strategies to control and/or eradicate invasive plant species. This study was carried out in the Kiama LGA in the Illawarra Region of New South Wales, about 120 kilometres south of Sydney. The specific aims were to: (i) identify and rank major invasive plants and their relative importance of concern across landowner types, (ii) characterise the focus and efforts of invasive weed management strategies adopted across landowner types and (iii) map the invasion network of drivers for Fireweed (Senecio madagascariensis), Lantana (Lantana camara), and Blackthistle (Cirsium vulgare) in the complex ecological, climatic, socio-political and cultural settings of the case study regions. The thesis drew on a questionnaire based postal survey (Appendix-A), personal interviews with the local weed officer and a literature review of relevant materials about the bio-physical and socio-ecological drivers of plant invasion. First, frequency of occurrences of all landowners (i.e., 355) was calculated to rank the top three invasive plants; Secondly, Pearson’s Chi-Square tests and Non-parametric Mann-Whitney U tests were applied to test the relative importance of concern about the top three invasive plants (i.e., Fireweed, Lantana and Blackthistle) and overall levels of concern of invasive plant species across landowner types (i.e. newer/longer-term landowners and farmers/lifestylers).Thirdly, multiple regression

We examined the effect of fire frequency and intensity on a Protea caffra tree population in the temperate montane grasslands of north-western KwaZulu-Natal, South Africa. We assessed the effect of fire by comparing the population structure of the resprouter P. caffra in discrete bracken (Pteridium aquilinum) patches with that in the surrounding grassland matrix. Fuel biomass did not differ between grassland and bracken, but bracken fuel was significantly drier than grass. Above-ground fire temperatures and fireline intensity, measured by P. caffra char height, were significantly higher in the bracken habitat. Forty-two percent of the P. caffra population in grassland and in bracken persisted by coppice resprouts, having lost their original stem to fire damage. Exposure to higher intensity bracken fire suppressed P. caffra regeneration and caused greater adult mortality compared with trees in grassland. Consequently, the P. caffra population in bracken was skewed towards old age with most trees severely fire damaged. The high incidence of small trees in grassland indicates that a regular fire interval of 2-3 years does not negatively affect regeneration of P. caffra. However, in bracken patches regular high intensity fires cause high mortality among all P. caffra size classes and will ultimately result in local extinction. Bracken thus has the potential to significantly alter tree-grass interactions in these montane grasslands.

Population differentiation of alien invasive plants within their non-native range has received increasingly more attention. Common gardens are typically used to assess the levels of genotypic differentiation among populations. However, in such experiments, environmental maternal effects can influence phenotypic variation among individuals if seed sources are collected from field populations under variable environmental regimes. In the present study, we investigated the causes of an altitudinal cline in an invasive plant. Seeds were collected from Senecio inaequidens (Asteraceae) populations along an altitudinal gradient in southern France. In addition, seeds from the same populations were generated by intra-population crossings in a climatic chamber. The two seed lots were grown in a common garden in Central Belgium to identify any evidence of environmentally induced maternal effects and/or an altitudinal cline in a suite of life-history traits. Results failed to detect any environmental maternal effects. However, an altitudinal cline in plant height and above-ground biomass was found to be independent of the maternal environment. © 2009 European Society For Evolutionary Biology., SCOPUS: ar.j, FLWIN, info:eu-repo/semantics/published

The present study had the objectives to obtain regression equations to estimate biomass production of Calotropis procera individuals, and to determine its chemical composition, based on specimens from two sites located in the municipal districts of Patos and Santa Luzia, State of Paraíba. In Patos (site I), 134 individuals were collected, while 149 ones were sampled in Santa Luzia (site II). At the moment stems were cut at 10,0 cm above the soil, stump base circumference and stem total length measures were taken for each plant. Then, total fresh biomass (leaves + fruits + flowers + stem + branches) was determined in the field, separately for each plant, and soil samples were collected for chemical characterization. Plant and soil materials were analyzed, respectively, at the Animal Nutrition and Soil and Water laboratories facilities, both located at the Center of Rural Health and Technology/UFPB, in Patos-PB. Plant biomass and total stem length data analyses were run through Microsoft Excel, version 2000, and four models, pre- defined by the software, were tested. Potency type model was chosen for both sites because it showed the highest coefficient of determination (R2 ). Estimated regression equations of fresh biomass (Y), in kg, as a function of stump circumference (X), in cm, for sites I and II resulted to be, respectively, Y = 0.0187920 X1.8174403 (R2 = 0,897) and Y = 0.0077919 X1.9213604 (R2 = 0,905). Biomass estimates using these equations make evident the existence of significant differences in Calotropis procera forage production between these two sites. Calotropis procera from site I showed higher crude protein, mineral and non-nitrogenous extractives contents than site II plants. However, site II plants presented higher contents of neutral and acid detergent fibers, dry matter, organic matter, hemicellulose and ether extract than site I plants. The present study demonstrated that Calotropis procera is a potential species to produce forage in the semi-ari, O presente estudo objetivou encontrar equações de regressão para estimar a produção de biomassa de Calotropis procera, e sua composição química, em dois sítios nos municípios de Patos e Santa Luzia, Estado da Paraíba. No Sítio I (Patos), foram coletados 134 indivíduos e, no Sítio II (Santa Luzia), 149 indivíduos. Por ocasião da coleta dos indivíduos, cortados a 10,0 cm de altura do solo, tomaram-se as medidas de circunferência na base cortada e o comprimento total da planta, sendo em seguida pesados individualmente, no campo, definindo assim o peso da matéria verde total (folhas + frutos + flores + caule + galhos). Por ocasião da coleta dos indivíduos de Calotropis procera retiraram-se amostras de solo de ambos os sítios para caracterizá-lo quimicamente. O material vegetal e o solo foram analisados nos Laboratórios de Nutrição Animal e de Solos e Água, do Centro de Saúde e Tecnologia Rural/UFPB, em Patos-PB. Os dados coletados no campo foram analisados através do Programa Excel da Microsoft, versão 2000, onde as variáveis foram comparadas para definição da melhor correlação, sendo testados quatro modelos pré-definidos pelo Software. O modelo na forma de potência foi o que apresentou maior R2 , sendo o escolhido para ambos os Sítios. Para o Sítio I a equação obtida foi: Y = 0,0187920 X1,8174403 com um R2 de 0,897; para o Sítio II Y = 0,0077919 X1,9213604 com um R2 de 0,905, sendo Y o peso verde em Kg e X a circunferência na base em cm. A estimativa de biomassa usando as equações obtidas, para os referidos sítios, comprovam a existência de diferenças significativas de produção de forragem de Calotropis procera entre os municípios estudados. No Sítio de Patos, as plantas de Calotropis procera apresentaram maiores teores de proteína bruta, material mineral e extrativos não nitrogenados, quando comparado ao Sítio de Santa Luzia. As plantas deste sítio apresentaram maiores teores de fibra em detergente neutro, fibra em detergente ácido, matéria seca, matéria orgânica, hem

The influence of invasive plant species on native community composition is well-documented, but less is known about underlying mechanisms. Especially scarce is knowledge about effects on biotic interactions such as relationships between native plants and their pollinators. In this study we investigate if pollen transfer from the invasive and highly pollen productive Carpobrotus spp. affects seed production and/or seed quality in three native species. We monitored pollinator movements and pollen loads on pollinators and native stigmas, and in a field pollination experiment we investigated the effect of invasive pollen on reproduction. Invasive pollen adhered to pollinators, pollinators switched from Carpobrotus spp. to natives, invasive pollen was transferred to native stigmas, and it affected seed production in one species. Although all possible steps for interference with seed production were found to be qualitatively taken, invasive pollen has probably little impact on the native community because the frequency of invasive pollen transfer to natives was low. However, pollination interactions may change with plant abundance and our study provides evidence that pollen transfer from Carpobrotus spp. to natives does occur and have the potential to affect seed production. We found the species identity of shared pollinators to be of importance, higher flower constancy and lower capacity of pollen adherence are likely to result in less invasive pollen transfer.

Senecio kleinia, an endemic plant of the Canary islands that is commonly used as an ornament in private gardens of the south-eastern Spanish coast, has been discovered invading some native plant communities of the Alicante coastal region. We suggest that a favourable microclimate, and the ability to disperse by both seed and vegetative growth, have allowed the plant to establish stable and spreading populations. The presence of potential habitat along the south eastern Spanish coast increases the risk of expansion of Senecio kleinia to many other localities including protected areas., Senecio kleinia, una planta endémica de las Islas Canarias, comúnmente utilizada como ornamental en jardines del sureste español, ha sido encontrada en dos localidades costeras alicantinas formando parte de diferentes comunidades vegetales. Así mismo, la existencia de un microclima favorable y la capacidad de la planta de reproducirse con éxito tanto vegetativamente como por semillas, han permitido la consolidación de poblaciones estables. La presencia de hábitats potenciales a lo largo de la costa sureste de la Península Ibérica incrementa el riesgo de expansión de la planta hacia otras localidades, entre las que se incluyen espacios protegidos.

Senecio kleinia, an endemic plant of the Canary islands that is commonly used as an ornament in private gardens of the south-eastern Spanish coast, has been discovered invading some native plant communities of the Alicante coastal region. We suggest that a favourable microclimate, and the ability to disperse by both seed and vegetative growth, have allowed the plant to establish stable and spreading populations. The presence of potential habitat along the south eastern Spanish coast increases the risk of expansion of Senecio kleinia to many other localities including protected areas., Senecio kleinia, una planta endémica de las Islas Canarias, comúnmente utilizada como ornamental en jardines del sureste español, ha sido encontrada en dos localidades costeras alicantinas formando parte de diferentes comunidades vegetales. Así mismo, la existencia de un microclima favorable y la capacidad de la planta de reproducirse con éxito tanto vegetativamente como por semillas, han permitido la consolidación de poblaciones estables. La presencia de hábitats potenciales a lo largo de la costa sureste de la Península Ibérica incrementa el riesgo de expansión de la planta hacia otras localidades, entre las que se incluyen espacios protegidos.

The spread of invasive plant species is an increasing concern in many parts of the world. Negative effects on biodiversity, public health concerns, or economic damage are reported from the most vigorous of them. The monocarpic Heracleum mantegazzianum (Giant Hogweed, Apiaceae) is one of these species in Central Europe. The aim of the individual-based model (IBM) presented here was to assess the invasion status of H. mantegazzianum. This research was motivated by a recent study conducted by [Hüls, J., 2005. Populationsbiologische Untersuchung von Heracleum mantegazzianum Somm. & Lev. in Subpopulationen unterschiedlicher Individuendichte. Dissertation. Justus-Liebig-Universität Giessen, Germany (in German)], which predicted declines in a number of German Hogweed populations. This result contradicted many current, as well as past observations. In the presented study, we intend to resolve this controversy. First, we show that the developed IBM is based on the same data set as the matrix model developed by [Hüls, J., 2005. Populationsbiologische Untersuchung von Heracleum mantegazzianum Somm. & Lev. in Subpopulationen unterschiedlicher Individuendichte. Dissertation. Justus-Liebig-Universität Giessen, Germany (in German)]. Yet, our results illustrate that the invasion status of H. mantegazzianum has not changed and that populations are still expanding in space. Second, the reason for this opposite result is analyzed. Results from the IBM were compared with those of the transition matrix models and with a reduced version of the IBM. We identify individual variability as the main cause, which is accounted for in the original IBM but missing in the original matrix model and the reduced IBM. Our studies also show that, although the long-term average of the population growth rate is larger than one and populations generally expand, there are years in which populations decline (actual growth rates R < 1). This highlights a need for longer-term monitoring

Ceratapion basicorne (Coleoptera: Apionidae) is a weevil native to Europe and western Asia that is being evaluated as a prospective classical biological control agent of Centaurea solstitialis (yellow starthistle) in the United States. Host plant specificity of the insect was evaluated in no-choice oviposition experiments. Feeding on leaf tissue by adult females was highly correlated to oviposition rate, both of which occurred primarily on plants in the tribe Cardueae, and especially those in the monophyletic subtribe Centaureinae. The highest rates of larval development occurred on Ce. solstitialis and Centaurea cyanus (bachelor’s button, garden cornflower), and there was significant development on Centaurea melitensis (Napa starthistle, tocalote), Cnicus benedictus (blessed thistle), Carthamus tinctorius (safflower), and Crupina vulgaris (common crupina). All the plants that supported some larval development are within a monophyletic clade within the Centaureinae. No native North American plants appear to be at risk of significant damage by this insect. Additional testing of safflower and bachelor’s button under choice conditions should complement these results to help determine the degree to which these plants are at risk.

Das Naturschutzgebiet `Lange Rhön` (2666 ha) liegt im Grenzraum der Bundesländer Bayern, Hessen und Thüringen. Seit einigen Jahrzehnten überwächst dort die Stauden-Lupine (Lupinus polyphyllus) artenreiche Storchschnabel-Goldhaferwiesen und Borstgrasrasen und impliziert dadurch Habitatsveränderungen für die zentralen Leitarten der Rhön (Wiesenbrüter: Birkhuhn und Wachtelkönig). Die Erhaltung repräsentativer Ausschnitte dieser Kulturlandschaft wird damit gefährdet. In der vorliegenden Arbeit wurden die Ursachen für den Etablierungserfolg und der damit verbundenen starken Ausbreitung von Lupinus polyphyllus in den Hochlagen der Rhön untersucht. Die Folgen für das Artenspektrum geschützter Biotoptypen im Biosphärenreservat Rhön wurden aufgezeigt und die Möglichkeiten eines zukünftigen Managements von Lupinus-Beständen anhand von Pflegeversuchen ermittelt und dargestellt. Die Ergebnisse lassen sich wie folgt zusammenfassen: 1. Der ursprünglich im Nordwesten Amerikas beheimatete Neophyt Lupinus polyphyllus wurde 1942 zur Standortsverbesserung in Fichtenaufforstungen der `Langen Rhön` eingesät. Diese mit Absicht erfolgte antrophogene Fernausbreitung von Lupinus polyphyllus war Voraussetzung für seine weitere Ausbreitung. 2. Die flächige Ausbreitung des Neophyten konnte erst durch Nutzungsveränderung in den letzten Jahrzehnten erfolgen. Durch die Veränderungen der Rahmenbedingungen in der Landwirtschaft (Verbrachung, späte Mahd, Minimalpflege) wurden die Eigenschaften des Neophyten Lupinus polyphyllus zur Einnischung in das Bergwiesenökosystem der Hochrhön gefördert. Der Vertragsnaturschutz hält eine Flächennutzung nur monitär über Prämien aufrecht, wodurch die Ausbreitungsmechanismen und -strategien von Lupinus polyphyllus z. T. unterstützt werden. 3. Die Amplitude der Pflanzengesellschaften, in denen sich Lupinus polyphyllus einnischt, reicht von artenreichen Borstgrasrasen über Goldhaferwiesen bis hin zu Feuchtwiesen und Kleinseggenrasen, wobei de, The nature reserve `Lange Rhoen` (2,666 hectares) is situated in the border area of the German federal states of Bavaria, Hesse and Thuringia. For some decades already the large-leaved lupine (Lupinus polyphyllus) has grown over a large number of species of crane's bill-yellow oat meadows and mat-grass pastures, and thus implies habitat changes for the leading species of the Rhoen region (meadow breeders: black grouse (Tetrao tetrix) and corncrake (Crex crex). The preservation of representative sections of this man-made landscape is thus jeopardized. The reasons for the settlement success and thus the extensive spread of Lupinus polyphyllus in the uplands of the Rhoen region was examined in this paper. The consequences for the variety of species in protected types of biotope in the Rhoen biosphere reserve have been described, and the possibilities for a future management of the Lupinus stock were determined and described by means of cultivation trials. The results can be summarised as follows: 1. The neophyte Lupinus polyphyllus originally resident in the north-western regions of America was used as sub-seed for location improvement in spruce afforestation in `Lange Rhoen`. This intentionally caused anthropic long-distance dispersal of Lupinus polyphyllus was the pre-requisite for its further spread. 2. The areal dispersal of the neophyte could occur only on account of the utilization changes in the last few decades. On account of the changes in the framework conditions in agriculture (fallow land, late hay harvest, minimum cultivation), the nature of the neophyte Lupinus polyphyllus to niching was supported in the ecological upland meadow system of the `Hochrhoen` region. Contractual protection of nature ensures land cultivation by premiums only, which supports the dispersal mechanisms and strategies of Lupinus polyphyllus in addition. 3. The amplitude of plant populations, in which Lupinus polyphyllus settles, reaches from a large number of

The alien plant species and the ecological factors that facilitate their invasion to a coastal strip in the Baix Camp region (Tarragona, NE Spain) were studied. A detailed inventory of the area showed that 20% of the plant species, most of them from the American Continent, were aliens, many of which were strongly invasive. At the habitat level, the relationships between the invasive behaviour and a number of autecological, ecological and habitat variables were analysed by means of logistic analyses. In the best model five variables were related to alien plant invasions climatic affinity, disturbance of the invaded habitat, route of introduction, soil moisture during summer, and life form. To elucidate the environmental factors that could be responsible for alien plant invasions at a regional scale, the number of alien taxa and the environmental features at 13 localities of the western Mediterranean area were analysed. The warm lowlands, subjected to low annual rainfall and high population density, exhibited the greatest reception capacity for alien plants. It is concluded that various specific environmental features - high mean temperatures, the abundance of riparian systems, the existence of biotopes with favourable water balance which harbour a great richness of alien species and the high human pressure to which the enclave is subjected, combined with the ecological requirements of the alien species and certain species attributes (biotype) can interact at different scales and have caused the over-representation of alien plants.

One of today’s largest ecological problems is biological pollution, or the spread of invasive plant and animal species. We lose 4600 acres daily to new weed infestations. The ecological and economic costs to the nation are staggering (Westbrooks 1996). In response, the Federal Interagency Committee on the Management of Noxious and Exotic Weeds (FICMNEW) helped draft Executive Order 13112. All 16 agencies involved were responsible for the field guidance that followed (NISC 2001). In accordance with the EO 13112 goals of prevention, control, restoration, and education, FHWA sent guidance to all state Departments of Transportation asking that analysis of invasive species be incorporated within the NEPA process. The 1999 guidance was aimed at preventing the spread of weeds on highway projects and through maintenance practices (Harper-Lore 2000). State case studies will demonstrate how this Executive Order was incorporated into national policy and translated to highway construction and maintenance projects.

The article is devoted to the study of the results of introduction of East Asian origin flowering plants, growing in the dendrological collection of Belgorod Botanical Garden. The most important ecological and biological characteristics of the plants were studied. The estimation of the growth and development nature of introduced species, according to their resistance to the complex of unfavorable factors, was carried out