The establishment and spread of invasive alien plant species (IAPS) outside their natural habitats have irreversibly affected native biodiversity in almost every habitat type.
For Southern ...Transylvania, we recognise that there are about 200 adventive plants. From those, we selected 18 IAPS that occupy riparian habitats, the most common, abundant, frequent or with higher impact on habitats and human health. We studied the history of their introduction in the study area, their distribution paths and means of spreading in the wild, their chorology and ecology.
There is substantial global concern over the potential impacts of plant invasions on native biodiversity in protected areas (PAs). Protected areas in tropical island countries that host rich ...biodiversity face an imminent risk from the potential spread of invasive alien plant species. Thus, the aim of this study was to gain a general understanding of the potential risks of multiple plant invasions in PAs located in the tropical island of Sri Lanka under projected climate change. We conducted a further analysis of a multi-species climate suitability assessment, based on a previous study using the Maximum Entropy (MaxEnt) modeling approach, and tested how species invasion may change in protected areas under climate change. We evaluated how the climate suitability of 14 nationally recognized invasive alien plant species (IAPS) will vary within PAs and outside PAs by 2050 under two climate change scenarios, representative concentration pathways (RCP) 4.5 and 8.5. Our findings suggest that there will be increased risks from multiple IAPS inside PAs and outside PAs in Sri Lanka in the future; however, the potential risk is comparatively less in PAs. We provide an overview of the species richness of selected threatened vertebrate groups, which can be potentially impacted by IAPS in PAs. The findings of this study highlight important implications for the strategic management of plant invasions in PAs in order to safeguard native biodiversity, with special reference to vertebrates.
Invasive alien plant species (IAPS) pose one of the most significant threats to native biodiversity. Swietenia macrophylla, or big leaf mahogany, is among the most threatening invasive plants in the ...Philippines. This article aimed to formally document the presence of S. macrophylla along the edges of Mt. Banahaw de Nagcarlan, a protected area on Luzon Island, Philippines. The study also sought to identify the management strategies being implemented by various government institutions to address big leaf mahogany and other invasive plants. A total of 1591 individuals of S. macrophylla were documented in mixed land-use areas and roadsides. These were found to have been introduced by the Department of Environment and Natural Resources in 1991 as a reforestation species. Fortunately, no individuals were observed beyond the buffer zone towards the protected area. The identification of management strategies for big leaf mahogany and other IAPS revealed that there is no established approach specifically addressing the presence of S. macrophylla at the site. However, some institutions advocate for the conservation of native plants through tree planting activities and educational campaigns. Furthermore, no collaborative efforts were observed among stakeholders and institutions. The results of this study highlight the urgent need to manage the S. macrophylla population. Planning and enforcement of strategies require collaborative efforts among stakeholders to prevent its entry into the protected area and ensure the preservation of native biodiversity.
Substrate salinity is one of the main abiotic factors limiting plant establishment, growth and distribution in coastal habitats. Nevertheless, few studies have investigated the interaction between ...salt concentration and duration of exposure on the physiology and growth of Carpobrotus edulis, an important invasive plant species growing in coastal dune habitats. In this study, four salinity treatment cycles of different length (three, six, twelve and twenty-four days) at salinity of 0M, 0.1M, 0.2M and 0.3M were imposed. A significant response in plant growth was elicited after 24days of treatment. The main shoot length (MSL) and stem biomass (SBMS) increased by 11% and 4%, respectively at 0.1M and by 25% and 6% at 0.2M compared with the control. At 0.3M MSL did not significantly differ from the control while SBMS was 18% lower. Moreover, C. edulis showed a high photoprotection mechanism efficiency resulting in a high carotenoid to chlorophyll ratio increase which was two, three and four times higher than the control at 0.1M, 0.2M and 0.3M, respectively. Photochemically, the quantum yield of photosynthesis (ΦPSII) was 17%, 50% and 52% lower than the control at 0.1M, 0.2M and 0.3M. The ΦPSII decrease was associated with a low leaf nitrogen content (NL) decrease (16%, 21% lower than the control at 0.1M and 0.2M, respectively). By contrast, NL had the highest decrease (41% lower than the control) at 0.3M, which constrains the growth capacity. Overall, C. edulis was able to modulate its response to salinity. The salt stimulated shoot elongation at low or moderate salt concentrations could confer a competitive advantage making C. edulis even more efficient in establishing within the areas which it colonizes. Since the expansion of C. edulis may be enhanced by the forecasted increase in soil salinity, it will be of paramount importance to apply effective management practices in areas invaded by C. edulis to limit its expansion and preserve the native plant biodiversity.
•Shoot elongation was stimulated at 0.1M and 0.2M salinity levels.•Shoot elongation was inhibited at a salinity of 0.3M.•C. edulis showed efficient functioning of photo-protection mechanisms.
Invasive alien trees and shrubs pose significant threats to biodiversity and ecosystem services in South African fynbos ecosystems. An ambitious initiative, the Working for Water program, commenced ...in 1995 to reduce the extent and impact of plant invasions. Despite substantial progress, the problem remains immense, and innovative ways of improving the efficiency of control operations are urgently needed. This study sought to develop a robust conceptual framework for effective management of the most important invasive alien plant (IAP) species. Two methods were applied in exploring the complexity of problems, thereby identifying appropriate response strategies. The DPSIR (Driving forces-Pressure-State-Impacts-Responses) framework and the Analytic Hierarchy Process (AHP) tool were used to design a strategy for prioritizing management actions. This strategy considers explicitly the most influential factors that determine the distribution, abundance, spread and impacts of IAPs. Efficient management of IAPs is constrained by multiple interacting environmental and socio-economic factors. Factors related to the fire-prone nature of the ecosystem and the characteristics of the invasive stands emerged as pivotal features for setting spatially-explicit priorities for management. Results of the analyses provide an objective and quantifiable perspective for improving the management efficiency. We conclude that considerable progress in controlling the spread of IAPs in fynbos ecosystems could be achieved by better coordination of management practices and by improving the quality of species distribution data.
We performed a detailed HPLC-MSn analysis of the phenolic compounds from the extracts of two invasive alien plant species (IAPS): Japanese knotweed (
(Houtt.) Ronse Decr.) and American pokeweed (
...L.). The major phenolic groups were hydroxycinnamic acids and flavanols in Japanese knotweed (J. knotweed) and flavonols, hydroxycinnamic acids, and stilbenes in American pokeweed (A. pokeweed). We investigated the influence of solvent type and extraction time on the extraction efficiency of the phenolic compounds. The solvent 80% methanol had a higher polyphenolic extraction efficiency than water, since 14.5 times more flavonols and 2.3 times more stilbenes were extracted from J. knotweed and 5.2 times more flavonols and 2.6 times more stilbenes were extracted from A. pokeweed. In contrast, with water, we obtained a 52% higher hydroxycinnamic acids (HCA) content from J. knotweed. Hydroxycinnamic acids were best extracted in water after 24 h, flavanols after 12 h, stilbenes between 12 and 24 h, and flavonol glycosides after 48 h of extraction. We also tested the allelopathic effect of the aqueous extract of A. pokeweed and J. knotweed on seed germination and shoot and root growth of perennial ryegrass. The results showed that the water extract of J. knotweed resulted in 38 to 48% lower seed germination of perennial ryegrass, and the extract of A. pokeweed resulted in 83 to 90% lower seed germination. The phytotoxic effect of the extract of J. knotweed and A. pokeweed was also reflected in a characteristic reduced growth of shoots and roots of perennial ryegrass. The phytotoxic action of IAPS could also be applied for beneficial purposes, since this would be an effective strategy for their control and a reduction of their spread in the environment.
In a laboratory experiment, we studied the insecticidal effects of invasive alien plants on the rice weevil. The research was carried out in two parts. In the first part, we studied the insecticidal ...properties of seven different plant species, namely, Bohemian knotweed (Fallopia × bohemica), Japanese knotweed (Fallopia japonica), false indigo-bush (Amorpha fruticosa), tree of heaven (Ailanthus altissima), staghorn sumac (Rhus typhina), Canada goldenrod (Solidago canadensis), and giant goldenrod (Solidago gigantea). Mixtures of powders and wheat were prepared in two different concentrations, namely, 2.5 w% and 1.25 w%. The experiment was performed at temperatures 20 °C and 25 °C and at two humidity levels, 55% R.h. and 75% R.h. Very low mortality (below 8%) was found when using combinations with the higher relative humidity. No significant differences were observed between the effects of these concentrations. In the second part of the experiment, Norway spruce wood ash and diatomaceous earth (product SilicoSec®) were added to the powder obtained by milling leaves of four different invasive plant species (Canada goldenrod, staghorn sumac, tree of heaven, false indigo). In the independent application, wheat was added to the powder at a concentration 2.5 w%. In the treatments that involved mixtures of powder and wood ash/diatomaceous earth, we applied 1.25 w% plant powder and 1.25 w% wood ash or 1.25 w% plant powder and 450 ppm of a SilicoSec® preparation. The positive control was carried out as two separate treatments with 2.5 w% wood ash of Norway spruce and 900 ppm of the SilicoSec® product, while untreated wheat represented the negative control. The experiment was performed at two temperatures (20 °C and 25 °C) and two R.h. values (55 and 75% R.h.). The mortality of beetles was recorded on the 7th, 14th, and 21st day after the start of the experiment. Higher mortality rates of rice weevil adults were found at the higher relative humidity, and an important factor of mortality was also the day of exposure, as a higher mortality was found when the exposure of individuals to the tested substances was for a longer time period. After 21 days at 25 °C and 55% R.h., the combinations in which the lower concentration of Norway spruce wood ash was added to the powder of invasive alien plants achieved more than 90% mortality of beetles. By adding the plant powder of invasive alien plants to wood ash, we achieved a greater insecticidal efficacy of invasive plants and lower concentrations of wood ash. Nevertheless, the results of our research do not indicate any great usefulness of the plant powder of invasive plants in suppressing the rice weevil. Additional studies should primarily focus on the insecticidal efficacy of powder from the genus Solidago, which in our study, displayed the greatest insecticidal potential among the tested invasive plants.
There have been few studies investigating the implications of the potential distribution of plant invasions on native biodiversity due to climate change. In this study, we used combined climatic ...suitability maps of 14 priority Invasive Alien Plant Species (IAPS) in Sri Lanka under the current climate and under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 climate scenarios for 2050 to examine the potential risks of plant invasions on native plant biodiversity. We used three types of layers defining plant biodiversity patterns for Sri Lanka; (i) nine zones of plant endemism (zones of high floristic richness and endemicity), (ii) eleven threatened endemic taxa and (iii) eight forest-related ecosystems. Our results reveal that the biodiversity-rich zones of endemism are at potentially high-risk under climate change. The potential risks on threatened endemic plants are likely to reduce slightly under an RCP 4.5 low-emissions scenario and be intensified under an RCP 8.5 high-emissions scenario. Forest-related ecosystems are vulnerable to IAPS to varying degrees; dry zone ecosystems are predicted to increase the risks of IAPS, while those in the wet zone are envisioned to decrease. Overall, our findings suggest that the potential risks of plant invasions on native plant biodiversity differ significantly under projected climate change. Greater understanding of the potential risks of IAPS at an early stage is important in prioritising future conservation measures for effective protection of native biodiversity.
With a rapid growth invasive alien plants cause a lot of problems not only to indigenous varieties of plants, but also for people, as they are often the cause of many health problems, such as ...allergies, and they also contribute to greater economic loss. Plant protection is an activity which, on the basis of appropriate scientific knowledge by means of various methods and an economical manner, protects cultivated plants from harmful organisms. In Slovenia, as well as worldwide, the use of pesticides in plant protection programmes is the most widespread method due to price and other benefits. Researchers are looking for new, environmentally more acceptable ways of protecting plants against harmful organisms due to adverse environmental effects of pesticides, their non-target activity, the occurence of resistance to pesticides, and increasingly stringent environmental policies. One such measure is also the study of plant extracts in the suppresing of economically important harmful organisms. In a review article, we focused on the literature review of the usefeulness of plant extracts of several invasive alien plant species in plant protection: knotweeds (Fallopia japonica Houtt. Ronse Decr), F. x bohemica (Chrtek & Chrtková) Bailey), goldenrods (Solidago canadensis L., S. gigantea Aiton), stag's-horn sumac (Rhus typhina L.), tree of heaven (Ailanthus altissima Mill. Swingle), false indigo (Amorpha fruticosa L.) and stinkwort (Dittrichia graveolens L. Greuter), which we are studying within the project ApPLAuSE.
The impacts of invasive alien plant species on native plants are generally well documented, but little is known about the mechanisms underlying their impacts on crop growth. A better understanding of ...immediate as well as legacy effects and of direct and indirect impacts of invasive alien plant species is essential for an improved management of invaded cropland. We investigated how Lantana camara impacts the growth of two subsistence crops (maize and cassava) through competition for resources, allelopathy and the indirect plant–plant interactions. We carried out two pot experiments using soils from invaded abandoned, invaded cultivated and non‐invaded cultivated crop fields. In the first experiment maize and cassava were grown alone or together with L. camara and half of the pots were treated with activated carbon to suppress allelochemicals. The effect of the soil microbial community on L. camara—crop interactions was assessed in a second experiment using autoclaved soil with 5% of soil from the three soil types. We found that L. camara reduced the growth of maize by 29%, but cassava was not affected. We did not find evidence of allelopathic effects of L. camara. Inoculation of autoclaved soil with microorganisms from all soil types increased biomass of cassava and reduced the growth of maize. Because L. camara only caused impacts when growing simultaneously with maize, the results suggest that removal of L. camara will immediately mitigate its negative impacts on maize.
The impacts of invasive alien plant species on native plants are generally well documented, but little is known about the mechanisms underlying their impacts on crop growth. We investigated how Lantana camara impacts the growth of maize and cassava through competition for resources, allelopathy and the indirect plant‐plant interactions. Because L. camara only caused impacts when growing simultaneously with maize, the results suggest that removal of L. camara will immediately mitigate its negative impacts on maize.
PDF
