Search Results (5)

The wide occurrence and expansive nature of invasive plant species are worldwide problems because these plants by their competitive character can lead to the loss of biodiversity. As a result, they significantly disrupt ecosystems, create economic damage and threats to human health, and diminish the quality of recreational resources. Therefore, sustainable, bio-based solutions are needed for their control, focusing on the utilization of their biomass after eradication. To better understand the potential application possibilities of invasive plants and their potential role in bioeconomy, species such as Lupinus polyphyllus—Lindl., Impatiens glandulifera Royle, Heracleum sosnowskyi Manden, Solidago canadensis L., Echinocystis lobata (Michx.), and Elodea canadensis Michx. were studied. These plants are not only widely spread but also form dense mono-stands and produce substantial amounts of biomass, which provides more options for their harvesting. In particular, their composition was analysed to assess the feasibility of their use for bioactive compound extraction. The amount of total polyphenols and flavonoids was determined in various parts of the studied invasive plants, and their corresponding radical scavenging activities were determined using DPPH, ABTS, FRAP and CUPRAC. The studied invasive plants are rich sources of polyphenols, and the highest concentrations were found in Impatiens glandulifera leaves, reaching a concentration of 7.78–11.75 g GAE/100 g DW, but in Lupinus polyphyllus, the highest concentrations of polyphenols were identified in the extracts of the flowers (12.77 g GAE/100 g DW) and leaves (11.88 g GAE/100 g DW) of the plant. Among the various plant parts studied, the leaves and flowers consistently showed the highest concentrations of polyphenols and flavonoids, as well as the greatest antioxidant and radical scavenging activities. These findings underscore the potential of invasive plant biomass as a source of valuable bioactive substances, particularly polyphenols, after the eradication of these invasive species. Full article

The climbing cucurbit Echinocystis lobata, native to North America and alien to many European countries, was assessed for its genetic diversity and differentiation across its introduced range of populations by applying markers of amplified fragment length polymorphism (AFLP). Various tests, including an evaluation of the intrapopulation diversity, principal coordinate, and molecular variance analyses, showed that the Central and Eastern European populations differing in geography and arrival history are also distinct in the genetic parameters. Genetic diversity, defined as the percentage of polymorphic AFLP loci, ranged within 28–62% (on average 51%) at the regional scale (in Romanian, Baltic State, and Central Russian populations), and was very similar to this parameter at the local scale (on average 52% for Lithuanian populations). The differentiation was significant among the populations of the regions (Ф = 0.125, p = 0.001) and at the local scale (among the Lithuanian populations of the different river basins, Ф = 0.058, p = 0.010). The Bayesian results suggested the presence of three genetic clusters among the 29 sites, with populations from Romania, Latvia, Estonia, and the northern part of Lithuania comprising one prevailing cluster, populations from the Nemunas river basin of Lithuania comprising either the former mentioned cluster or the second cluster, and populations of Central Russia comprising the third genetic cluster. Overall, E. lobata in Europe has probably originated from multiple introductions. The intentional anthropogenic seed dispersal by marketing accompanied by hydrochory might have an impact on such a profile of genetic clusters. Full article

In climbing plants, fruits can be formed at different heights, depending on the height of external support. However, the effect of height on fruit and seed traits in invasive vines of Cucurbitaceae has not been intensively studied so far. In Europe, Echinocystis lobata, a North American member of Cucurbitaceae, is considered one of the most abundant invasive alien plants spreading in natural riparian forests, thickets, and tall herbs, whereas it is a rare species in urban woodlands. In this study, we tested the variability of selected fruit and seed traits of E. lobata in connection with habitat origin (natural, semi-natural, and anthropogenic), habitat type (using the EUNIS habitat classification), height (the distance between the fruit and the ground), and geographical position. The study was conducted in 2018 in 65 sites located in Latvia, Lithuania, Poland, and Slovakia. In each study site, a random sample of 10 fresh mature fruits of E. lobata was collected from subsequent 0.50 m intervals of height. The length, the width, and the weight of the fresh fruits, as well as the total number of seeds and number of undeveloped seeds per fruit, were examined. Moreover, the well-developed seeds from selected study sites were weighed. The statistical analysis showed the significant effect of habitat origin, habitat type, and height on most of the studied fruit and seed traits. The largest range of height (from 0.00 to 4.00 m) was observed in two types of habitats (F—heathland, scrub, and tundra; and G—woodland, forest, and other wooded land). The total number of seeds per fruit was positively correlated with the length, width, and weight of the fresh fruits. The fruits were a little heavier and bigger in natural habitats located in the northeast of the study area. The distribution of fruits at different heights may contribute to better dispersal of seeds by animals and wind, and may also better protect the seeds from being eaten by granivorous animals. The defence against seed-eating animals is expected to be stronger in semi-natural habitats, as well as on banks and shores of inland surface waters, where the seed production is the highest. The influence of seed traits on seed germination and seedling survival in various habitats and their importance in the invasiveness of E. lobata require further study. Full article

We investigated the presence and abundance of invasive alien plant species (IAS) in the riparian zones of rivers in relation to different environmental parameters. We surveyed the spatial and human-influenced characteristics of the riparian zones, river channels, and land use along seven Slovenian rivers. We further monitored the presence and abundance of IAS with different natural properties and different human impacts to define the characteristics of non-infected and heavily infected reaches. Special attention was given to different life forms of IAS. The presence and abundance of IAS positively correlated with distance from river source, current velocity, and water depth, and negatively correlated with altitude, naturalness of the land use, width and completeness of the riparian zone, height and structure of its vegetation, and condition of the riverbed and banks. Annuals prevailed among IAS at 48%, with 37% herbaceous perennials and 15% woody species. The vine Echinocystis lobata was the most abundant IAS, which was found in 179 out of the 414 river reaches analysed, followed by the annual Impatiens glandulifera and the herbaceous perennial Solidago gigantea. E. lobata was spread over the native riparian vegetation and was affected by the natural gradients of the rivers in terms of altitude and distance from the river’s source. Reaches without IAS significantly differed from reaches colonised with IAS in the width of riparian zone, vegetation height and structure, land-use next to the river, and distance from the source. As IAS in riparian zones affect riparian and aquatic communities, there is the need for management practices to maintain and establish complex riparian zones that are resistant to IAS colonisation. Full article

The vines Echinocystis lobata and Parthenocissus quinquefolia are spreading over the natural vegetation in riparian zones, which may significantly affect riparian vegetation properties and the quality of litter for aquatic organisms. We examined leaf morphological, biochemical and optical traits of these invasive alien species, each paired with its host, the willows Salix caprea and S. fragilis, respectively. The vines altered the host radiation environment and the amount of photosynthetic pigments. Both vines had significantly higher specific leaf area and lower leaf tissue density compared to the willows, even though the leaves of P. quinquefolia were significantly thicker. Leaf optical properties varied significantly between vines and willows in some spectral regions. Compared to the willows, the vines reflected less light as UV, and more as green, and transmitted more light as green, yellow and red. The overgrowth of the willows with vines affected the reflectance of the willow leaves. Redundancy analysis of the relationships between leaf biochemical traits and reflectance spectra showed that chlorophyll a, anthocyanins, and UVB- and UVA-absorbing substances explained 45% of the reflectance spectra variability, while analysis with morphological traits revealed that specific leaf area, leaf thickness and upper cuticle thickness explained 43%. For leaf transmittance, UVB- and UVA-absorbing substances, carotenoids and anthocyanins explained 53% of the transmittance spectra variability, while analysis with morphological traits revealed that specific leaf area explained 51%. These data show that invasive alien vines can be discerned from each other and their hosts by their spectral signatures. In addition, the differences in the leaf functional traits between the vines and their hosts indicate significant differences in the quality of the plant litter entering the river. Full article