Beyond ecological and health impacts, invasive alien plant species can generate indirect and direct costs, notably through reduced agricultural yields, restoration, and management of the invaded ...environment. Acacia dealbata and Ailanthus altissima are invasive plant species that cause particularly significant damage to the railway network in the Mediterranean area. The allelopathic properties of Mediterranean plant species could be used as nature‐based solutions to slow down the spread of such invasive plant species along railway borders. In this context, a mesocosm experiment was set‐up: (i) to test the potential allelopathic effects of Cistus ladanifer, Cistus albidus, and Cotinus coggygria leaf aqueous extracts on seed germination and seedling growth of A. dealbata and A. altissima; (ii) to evaluate whether these effects depend on the extract dose; and finally, (iii) to estimate whether these effects are modified by soil amendment. Leaf aqueous extracts of the three native plant species showed negative effects on both seed germination and seedling growth of the two invasive species. Our results show that the presence of allelochemicals induces a delay in seed germination (e.g., A. dealbata germination lasted up to 269% longer in the presence of high‐dose leaf aqueous extracts of C. coggygria), which can lead to a decrease in individual recruitment. They also highlight a decrease in seedling growth (e.g., high‐dose C. coggygria leaf aqueous extracts induced a 26% decrease in A. dealbata radicle growth), which can alter the competitiveness of invasive species for resource access. Our results also highlight that compost addition limits the inhibitory effect of native Mediterranean plants on the germination of invasive alien plants, suggesting that soil organic matter content can counteract allelopathic effects on invasive alien plants. Thus, our findings revealed that the allelopathic potential of certain Mediterranean plant species could be a useful tool to manage invasive plant species.
In this study, we provide clear evidence that the leaf aqueous extracts of three Mediterranean native species (Cistus albidus, Cistus ladanifer and Cotinus coggygria) exhibit negative allelopathic effects on seed germination and seedling growth of the two invasive plant species (Acacia dealbata and Ailanthus altissima). These allelopathic effects increased with dose extract but are greatly reduced and even canceled in the presence of soil amendment.
Display omitted
•The niche model was used to simulate the distribution dynamics change of four invasive plants with serious harm in China.•The population density, temperature, and precipitation were ...found to be the most important variables for the distributions of the plants.•The population density is a common and critical factor affecting the distribution of the four species.•The habitats of all the plants will massively expand northwards.
The distribution dynamics of invasive alien plants is the fundamental information for early detection and rapid response (EDRR) to these species in a new habitat. Based on the field survey data and online databases, the present research work utilized Maximum Entropy model (Maxent) to simulate the distribution dynamics of four invasive plants Ageratina adenophora (Spreng.) R. M. King et H. Rob., Alternanthera philoxeroides (Mart.) Griseb., Ambrosia artemisiifolia L. and Mikania micrantha Kunth in China, under current and future climate (2041–2060, 2061–2080, 2081–2100) in two shared socio-economic pathways (SSPs: SSP 245 and 585) of the newly released coupled model intercomparison project phase6 (CMIP6). All the suitable habitat areas of these plants will significantly expand in the future, but at different expansion levels. M. micrantha will have the largest distribution area (increase by 61–120%), while A. adenophora will expand by 7–33%, A. philoxeroides by 12–74%, and A. artemisiifolia by 8–27%, respectively. Additionally, the habitat centers of the four species will shift to north, i.e., A. philoxeroides, A. artemisiifolia and M. micrantha to northwest, and A. adenophora to northeast, except that the core distributions of A.adenophoraand A. artemisiifolia will move to southwest under one certain environment scenario (SSP 245 in the period of 2061–2080). Compared to aspect index and slope topographical variables, the population density, temperature, and precipitation are found to be more important variables in describing the distribution of these plants. The dynamics of habitats of these four species and the correlating driver factors proposed in this work provide essential insights into future spatial management of invasive plants and biodiversity conservation in China, which is, not only human activities should be regulated and the migration of invasive species be reduced, but also the monitoring of high-risk areas should be strengthened in order to ensure effective EDRR.
Tropical savanna and dry forest in Indonesia are an important type of ecosystem that supports various endemic wildlife of Indonesia including savannas at Padar and Komodo Islands which is home to the ...Komodo (Varanus komodoensis). The Komodo dragon is considered as “Vulnerable” by the International Union for Conservation of Nature. Studies with regards to the Komodo dragons’ habitats are scarce, considering that these types of habitats are significant to support Komodo’s existence, but yet are also very prone to conversion and disturbances. This paper elaborates the results of ecological study on the tropical savanna forest in Komodo National Park as habitat for the Komodo dragon. Vegetation sampling was conducted using nested plots 20 x 20 m, 10 x 10 m, 5 x 5 m and 2 x 2 m spread across the sampling sites. Data was analysed using PRIMER software which includes cluster analysis, analysis of similarity (ANOSIM) and similarity percentage (SIMPER). As many as 17 plant species which belongs to 11 families were identified in the sampling sites. These consist of six trees habitus, six shrubs, four grasses and one palm. Asteraceae, Fabaceae and Poaceae were the plant families which has high number of species. The result of cluster analysis shows that the similarity level of the two groups (Komodo and Padar) based on the results of cluster analysis is 60%. This result infers that there are similarities in terms of species composition in savanna on Komodo and Padar Island, however, each savanna still has its own species characteristics. This is confirmed by the ANOSIM test. The ANOSIM test results show the Global R value of 0.6.With the looming challenges from invasive alien plant species (IAPS), the Komodo Island’s savanna has double threats to overcome. Hence conservation of the remaining savanna ecosystem is important
A valorization strategy for an aggravating type of plant waste is put to the test herein. It envisions the use of Japanese knotweed green leaves as a sustainable source of free lutein, from which ...bioactive diesters could be prepared as potential value-added products with improved properties. To this end, 13 structurally distinct model lutein diesters were synthesized and the relationships between their structure and stability were systematically determined. The forced degradation data show that the stability of a particular lutein diester may depend to a large extent on the type of exposure (elevated temperature, light, oxidant, or acidic environment) and, more importantly, not every esterification attempt necessarily leads to an enhancement of lutein's chemical stability. However, three branched and bulky products-lutein di(2,2-dimethylpropanoate), lutein di(2-methylpropanoate), and lutein di(3-methylbutanoate)-proved to be particularly relevant, as they consistently exhibited 1.5-21-fold higher stability compared to free lutein, regardless of the stress conditions used. Finally, we show that the Japanese knotweed plant matrix had a significant negative or positive effect on pigment degradation kinetics that could not be easily predicted. Thus, the proposed valorization strategy is quite feasible, but the esterification approach should be tailored to the intended use of a lutein diester.
The American bramble (Rubus cuneifolius), a woody perennial invasive shrub, presents serious ecological and economic impacts, particularly in ecologically rich and protected landscapes. Since the ...ecological factors determining its geographic distribution are poorly understood, a comprehensive analysis and understanding of its potential distribution are essential to understand probable impacts and plan control interventions. Hence, this study sought to explore the use of Maximum Entropy (Maxent) modelling approach to determine the potential distribution of American bramble in the uKhahlamba Drakensberg Park (UDP), South Africa. Four sets of model scenarios based on topographic data, topographic and remotely sensed data, topographic and bioclimatic data and a composite of all variables were generated using 73 occurrence points. Model performance was evaluated using Area Under the Curve (AUC), True Skill Statistic (TSS) and Kappa statistic. The model built using a composite of all variables yielded the highest accuracies, AUC score (0.957), indicating the best prediction of suitable and unsuitable areas for bramble. The inclusion of remotely sensed data improved model performance with bramble reflecting highly on the red edge bands. Elevation and rainfall of driest quarter were the most important variables associated with bramble distribution. The models predicted low elevation, warm and moist eastern parts as most suitable for bramble establishment and growth. Overall, all the models matched in terms of the geographic extent predicted as probable bramble distribution. Our results demonstrate that an integration of topographic, bioclimatic and remotely sensed variables are useful in determining landscape vulnerability to bramble invasion and provide a valuable tool for planning control strategies.
•How plant invasions vary across vegetation type poorly known, particularly in the Himalaya.•Dominant forest types and grasslands studied in south-central Nepal.•Highest number of invasive plants in ...grasslands and the lowest in Shorea robusta forest.•Grasslands be prioritized for early detection and control of invasive plants.
Understanding the patterns of plant invasions across vegetation types and identifying the underlying drivers for such patterns is essential to prioritize sites for the effective management of invasive species. We sampled three forest types (Shorea robusta, Dalbergia sissoo, and Tropical deciduous riverine forest) and two grasslands in south-central Nepal to evaluate the richness of naturalized and invasive alien plant species (IAPS). Species richness of naturalized species and the IAPS among vegetation types within each physiographic region was compared using analysis of variance and t-test, and the ordination was used to analyze species-environment relations. Of the total 327 species of vascular plants recorded, 14 % were naturalized, and over a third of the naturalized species were invasive. Grasslands had the highest richness of naturalized species and the IAPS. In contrast, S. robusta forest had the lowest naturalized and IAPS richness. Naturalized species richness increased with native species richness. Ordination revealed that a high number of IAPS were associated with areas exposed to frequent fire and livestock grazing and close to human settlements. The results suggest that the grasslands closer to the human settlements and exposed to frequent disturbance are vulnerable to the establishment of IAPS. Early detection and control of IAPS in such frequently disturbed grasslands would prevent their spread into the surrounding landscapes.
Invasive alien plant species (IAPS) have negative impacts on ecosystems, including the loss of biodiversity and the alteration of ecosystem functions. The strategy for mitigating these impacts ...requires knowledge of these species' spatial distribution and level of infestation. In situ inventories or aerial photo interpretation can be used to collect these data but they are labor-intensive, time-consuming, and incomplete, especially when dealing with large or inaccessible areas. Remote sensing may be an effective method of mapping IAPS for a better management strategy. Several studies using remote sensing to map IAPS have focused on single species detection and were conducted in relatively homogeneous natural environments, while other common, more heterogeneous environments, such as urban areas, are often invaded by multiple IAPS, posing management challenges. The main objective of this study was to develop a mapping method for three major IAPS observed in the urban agglomeration of Quebec City (Canada), namely Japanese knotweed (Fallopia japonica); giant hogweed (Heracleum mantegazzianum); and phragmites (Phragmites australis). Mono-date and multi-date classification approaches were used with WorldView-3 and SPOT-7 satellite imagery, acquired in the summer of 2020 and in the autumn of 2019, respectively. To estimate presence probability, object-based image analysis (OBIA) and nonparametric classifiers such as Support Vector Machine (SVM), Random Forest (RF), and Extreme Gradient Boosting (XGBoost) were used. Overall, multi-date classification using WorldView-3 and SPOT-7 images produced the best results, with a Kappa coefficient of 0.85 and an overall accuracy of 91% using RF. For XGBoost, the Kappa coefficient was 0.81 with an overall accuracy of 89%, whereas the Kappa coefficient and overall accuracy were 0.80 and 88% for SVM classifier, respectively. Individual class performances based on F1-score revealed that Japanese knotweed had the highest maximum value (0.95), followed by giant hogweed (0.91), and phragmites (0.87). These results confirmed the potential of remote sensing to accurately map and simultaneously monitor the main IAPS in a heterogeneous urban environment using a multi-date approach. Although the approach is limited by image and reference data availability, it provides new tools to managers for IAPS invasion control.
•Fine-scale field data allows modelling alien plant invasion in sandy coastal areas.•Patterns of presence and abundance respond to different combinations of factors.•Fine-scale data helps identifying ...conditions with the highest probability of invasion.•Attributes of the resident community are important predictors of the invasion level.•Results provide hints to prevent alien species establishment and spread.
Invasive alien species risk assessment and adaptive management are often hindered by a lack of information for most species. This work aims at predicting the probability of successful establishment and invasion of Oenothera stucchii Soldano, a neophyte invasive species belonging to the sect. Oenothera subsect. Oenothera, in xerophilous grasslands of grey dunes. Based on fine-scale field data, we modelled O. stucchii presence/absence and abundance as a function of environmental factors, human disturbance, and attributes of the recipient community through a zero-inflated Poisson model. The invasion success of O. stucchii depended on a combination of factors which differed when considering either the patterns of occurrence (species presence/absence) or those of species abundance. While human-driven disturbance strongly influenced the probability of presence/absence of O. stucchii, patterns of abundance were mostly driven by a combination of environmental and biotic features. Attributes of the recipient community remarkably influenced both O. stucchii presence and abundance. Based on fine-scale field data, we determined the mechanisms which drive the spatial patterns of presence and abundance of O. stucchii in xerophilous grasslands and provided quantitative thresholds to identify the most susceptible areas of grey dune habitats prone to invasion, which combine human disturbance (distance from the nearest beach access), attributes of the resident community (resident vegetation cover and structure), and environmental disturbance (foredune ridge height). These results provide useful insights to be used to plan cost-effective measures to prevent O. stucchii establishment and spread in sandy coastal systems. Our model may also be applied to closely related congener species included in the subsect. Oenothera, sharing similar biological and ecological traits.
Invasive alien plant species (IAPs) in urban areas can have detrimental effects on biodiversity, ecosystem services and human well‐being. Urban areas are complex social management mosaics with high ...land‐use diversity, complex land tenure patterns and many different stakeholder groups, some of which derive benefits from invading species. Urban conservation practitioners face complex decisions about which IAPs require management. Yet most IAPs prioritization frameworks have been designed for and implemented in natural or rural areas and are generally inadequate for guiding effective and sustainable interventions in urbanized areas.
We modified an existing prioritization scheme to develop a framework for prioritizing terrestrial IAPs in urban areas which applies evidence‐based (data‐driven) and stakeholder‐based (local knowledge) assessments to score and rank alien plant species in terms of their priority for management using an objective set of criteria.
The framework consists of 46 criteria, grouped into eight modules which assess invasion status, habitat requirements, biological characteristics, dispersal ability, distribution, impacts (positive and negative) and potential for control for each alien plant species under consideration.
We use the city of Toronto, Canada as a case study to test our framework—a list of 50 IAPs were effectively scored and ranked in order of high to low priority for control. Species with the highest total prioritization scores were Vincetoxicum rossicum (Dog Strangling Vine), Convolvulus arvensis (Field Bindweed) and Taraxacum officinale (Common Dandelion, ranked 1, 2 and 3 respectively).
Many of the identified high priority species align with those previously flagged as of management concern by conservation practitioners, but also include those that are not actively managed due to their perceived lower ecological impacts. These species still require high resource investment for other objectives such as aesthetics. This highlights the complexity of alien plant species management in urban areas.
Synthesis and applications. Prioritizing invasive alien plants for management in urban areas is particularly challenging due to often conflicting ecological, economic and social objectives. We use available evidence and local stakeholder knowledge to develop an objective and systematic prioritization tool which can assist conservation practitioners in selecting priority species for management action in complex urban landscapes.
Prioritizing invasive alien plants for management in urban areas is particularly challenging due to often conflicting ecological, economic and social objectives. We use available evidence and local stakeholder knowledge to develop an objective and systematic prioritization tool which can assist conservation practitioners in selecting priority species for management action in complex urban landscapes.
PDF
