The distribution of selected woody invasive alien species in small towns in the Eastern Cape, South Africa

Across the continents, plant invasion is identified as one of the main threats to ecosystem functioning and stability. The main objective of this research was to evaluate the differences in the functional traits between invasive alien (Ageratina adenophora (Spreng.) and Lantana camara L.) and native (Berberis asiatica Roxb. Ex DC., Pyracantha crenulata (D. Don.) M. Roemer and Rubus ellipticus Sm.) shrub species of chir pine (Pinus roxburghii Sarg.) forest in the central Himalaya. Three 0.5 hectare chir pine forest stands were selected and individuals of similar diameter were tagged for comparative studies of leaf traits, growth pattern, and biomass accumulation in structural organs of each invasive alien and native species. Our one-way ANOVA and Tukey’s post hoc test results showed that both the invasive alien species have significantly (p < 0.05) higher SLA, LWC, total chlorophyll content, foliar nutrient (N and P), RGR, LMR, SMR, nutrient uptake, and nutrient use efficiencies than native species. Leaf litter decomposition rate and nutrient release were also significantly (p < 0.05) higher in both the invasive alien species. Native species, R. ellipticus, shared some of the traits, such as leaf area, chlorophyll content, RGR, LAR, LMR, and nutrient uptake efficiency with invasive alien species. The majority of traits differed among invasive alien and native species, implying that the success of invasive alien species is best described by being functionally distinct from native species. These findings indicate that invasive alien species had advanced functional traits which may be playing an important role in a rapid spread in the central Himalaya.

Invasive alien species and planetary and global health policy

Five major invasive alien tree species in European Union forest habitat types of the Alpine and Continental biogeographical regions

Biodiversity loss caused by invasive species may soon surpass the damage done by habitat destruction and fragmentation. Biological invasions are an important component of human-caused global environmental change. Invasive alien species are now a major focus of global conservation concern. The decisions need to be made on whether benefits derived from the invasive spread of an alien species outweigh the reduced value of ecosystem services, e.g. the loss of grazing land in areas invaded with Lantana camara and Senna occidentalis . It is necessary to consider actions to deal with the current problems caused by invasive species and to reduce the magnitude of the problem in the future. The present catalogue on invasive alien plant species of the northwestern &amp; Western Ethiopia is therefore timely one. It focuses on some species of invasive alien plants in Ethiopia. These include the most serious invasives, such as Alternanthera philoxeroides, Cassia uniflora, Chromolaena odorata, Eichhornia crassipes, Lantana camara, Parthenium hysterophorus , Senna obtusifolia and others. I am confident that this publication will be immense value to foresters, environmentalists, field researchers and conservation managers to pay attention on the ecological impact of invasive aliens both at the species and at the ecosystem levels. Keywords : Biodiversity, invasive species, conservation, environmental change DOI : 10.7176/ALST/74-04 Publication date :May 31 st 2019

Objectives:We assessed the diversity of invasive alien plant species in the Wayanad Wildlife Sanctuary (one of the main protected areas located in the Nilgiri Biosphere Reserve) to see whether the density and diversity were associated with forest canopy cover. This study was carried out in the pre-monsoon season from January to March 2015, when deciduous trees had shed their leaves and the canopy was relatively open.Methods: A total of 45 (20 m by 20 m) quadrats in different areas of the sanctuary were sampled. The total area sampled was 1.8 ha. All the plant species with a height of 10 cm and above were recorded and after proper identification only invasive alien species were considered. The GPS coordinates, the type of canopy cover (evergreen or deciduous) and the percentage of canopy cover were also recorded.Results: A total of 22 invasive alien plant species belonging to nine families was recorded. Out of this, 14 species (64%) belong to the Neotropics, 5 species (23%) to Africa, 2 species (9%) to West Indies and 1 species (4%) to South East Asia. Eupatorium odoratum (42.8±6.3) had the highest density followed by Lantana camara (13.6±3.2). Eupatorium odoratum was significantly and negatively correlated with canopy cover (Pearson’s correlation coefficient = -0.38, p=0.03), whereas L. camara was not associated with canopy cover (Pearson’s correlation coefficient = - 0.09, ns). This suggests that E. odoratum is more sensitive to the light levels than L. camara.Conclusion: This study provides little insights into the status of invasive alien species in an area known for its high levels of endemism.

Distribution and management of invasive alien plant species in protected areas in Central Europe

Many biological invasions result in negative impacts on the environment and human livelihoods, but simultaneously some also provide benefits that are valued differently by various stakeholders. To inform policy and management of invasive species it is important to assess landowners’ and broader society’s knowledge and perceptions of invasive species, something which is lacking in many contexts, especially in urban settings. In this study we interviewed 153 householders living in a medium-sized South African town who had declared invasive alien trees in their gardens. Less than half of the respondents could identify the invasive tree on their property and only one-third knew that it was an invasive alien species. There was a positive association between income and education levels with exposure to media about invasive alien species and respondents’ ability to identify the species and name any other invasive alien tree species. Knowledge levels were unequal across species. Amongst those who knew the tree was an invasive alien species, reasons why they retained it in their gardens included that it would be costly or too much effort to remove, they liked the tree, that it was not causing any harm and that the property was rented and so its removal was not their responsibility. However, the majority of people (83 %) were willing to have it removed from their garden if done for free by appropriate agencies, which is promising for compliance with new regulations on invasive species implemented at the end of 2014 in South Africa. The results also highlight the need for targeted and appropriate education and awareness programs amongst urban householders on invasive alien species, relevant legislation and their obligations.

Gymnocoronis spilanthoides

Simple SummaryEvery year, the South African government spends approximately ZAR 2 billion to control invasive alien species (IAS) that are intentionally or unintentionally introduced into new areas by humans, and have a variety of social, ecological, and economic impacts. Given the link between people and the introduction and spread of IAS, it is important to understand citizens’ knowledge and perceptions of IAS to guide management. For this reason, we conducted a study in small towns of South Africa to assess (1) awareness of IAS by the general public, (2) local perceptions of the impacts associated with IAS, (3) if awareness of IAS is associated with demographic covariates and IAS density, and, (4) people’s willingness to detect, report, and support IAS management. We found that people were not aware of IAS and their impacts, and many perceived them as beneficial. We found that IAS density, education level, and gender influenced people’s knowledge and perceptions about IAS in the region. Some people showed interest and willingness to learn more about IAS. These results could help to inform outreach and educational programs to promote public awareness and engagement in IAS management.Invasive alien species (IAS) are a growing threat globally and cause a variety of ecological, economic, and social impacts. People can introduce IAS and facilitate their spread, and can also implement, support, or oppose their management. Understanding local knowledge, awareness, and perceptions are therefore crucial if management and policy are to be effective. We administered questionnaires to members of the public in eight small towns along the Berg River Catchment in the biodiverse fynbos biome of South Africa. We aimed to assess: (1) awareness of IAS by the general public, (2) local perceptions of the impacts associated with IAS, (3) whether awareness of IAS is correlated with demographic covariates and IAS density, and (4) people’s willingness to detect, report, and support IAS management. Overall, 262 respondents participated in the survey. Most respondents (65%) did not know what IAS are, and 10% were unsure. Many respondents also perceived IAS as beneficial. Using a logistic regression, we found that IAS density, educational level, and gender influenced people’s knowledge and perceptions about IAS in the region. There were a small number (4%) of respondents currently detecting and reporting IAS, but many respondents were interested to learn more. We concluded that people living in small towns in the Western Cape of South Africa remain largely unaware of IAS and their impacts. It is crucial to increase awareness-raising initiatives, and build support and engagement in management of IAS in small towns.

Ecological impact of phytoinvasions in Ukraine

Invasive alien species threaten biodiversity with domestic gardens acting as a major pathway for the introduction of alien species. Even though the Nordic region is not currently a hotspot for biological invasions, the number of invasions in the Nordic area has been predicted to increase due to climate change. Given a time lag between introduction and invasion, many non-invasive horticultural alien species already introduced into gardens may become invasive in the future. This study aimed to identify the communication needs of Swedish garden owners regarding their management of invasive alien species. A survey among domestic garden owners, informed by topic specialists and local area experts, and interviews with garden owners were conducted in three different bio-climatic areas in a latitudinal gradient across Sweden. The questions targeted invasive alien species and their relations to biodiversity loss and climate change, as well as measures taken to control these species. Analysing the survey data collected in relation to measures taken to control invasive species, Bayesian Additive Regression Tree (BART) modelling was used to identify geographically varying communication needs of the domestic garden owners. In all study areas, the garden owners' measures taken to control invasive alien species were correlated with their strength of beliefs in having experienced local biodiversity loss. A majority of the garden owners were, moreover, uncertain about the impact of climate change on the invasiveness of alien species. In addition, the garden owners' capacity for identifying invasive alien species was often in need of improvement, in particular with respect to the species Impatiens glandulifera, Reynoutria japonica and Rosa rugosa. The results suggest that the evidence-based guidelines for effective communications we developed, have the potential to help communicators meet the local communication needs of garden owners across Sweden, in relation to the management of invasive alien garden species.

Ethnobotanical relevanceInvasive alien plant species are used individually or in combinations to treat sexually transmitted infections (STI's). However, ethnobotanical information of invasive alien species is scanty, especially on the treatment of STI's. The aim of the studyDocument ethnobotanical applications of invasive alien species in the treatment of STI's in the Waterberg District of Limpopo Province, South Africa. Materials and methodsAn ethnobotanical survey was conducted in the Waterberg District. Using a semi-structured questionnaire, 30 traditional health practitioners were selected via snowball sampling. Importance of medicinal plants was analysed using Fidelity Level (FL), Informant Consensus Factor (ICF), and the Use Value (UV). ResultsFourteen invasive alien species belonging to ten families were documented for the treatment of seven STI's. Plant species were mostly utilised for their roots (58.8%) and leaves (23.6%). Up to 60% of the species were used individually, while combination therapy was also common (40%). A decoction was the preferred method of preparation. The administration mode was predominantly oral (92.7%). Important species with high FL and with high use-report were Opuntia ficus-indica (63.9) and Catharantheus roseus (57.3). The highest ICF values were cited for mokabe (testicular swelling) (1) and gonorrhoea (0.73), with Senna didymobotrya and C. roseus being the most frequently used species. Species with the highest UV values were C. roseus (0.65), Agave sisalana (0.41) and Solanum elaegnifolium (0.55). ConclusionAgave sisalana, Catharanthus roseus, Opuntia ficus-indica, Ricinus communis, Senna didymobotrya, and solanum species were the most commonly used species for the treatment of sexually transmitted infections in the Waterberg District. Further pharmacological studies are encouraged on the species with the highest FL, ICF and UV values.

Extent of plant invasions has been expected to be low in protected areas such as national parks due to low anthropogenic activities and high wilderness. However, recent researches across the world have revealed that plant invasions can be severe in the national parks with negative impacts on the protected species and ecosystems. Unfortunately, the status of plant invasions in the national parks of Nepal is mostly unknown. In this study, we sampled at seven locations inside the Parsa National Park (PNP) to document diversity and abundance of invasive alien plant species (IAPS) and their impacts on tree regeneration. Altogether, 130 quadrats of 10 m × 10 m were sampled. We recorded 14 IAPS in the PNP. Three of the IAPS (Chromolana odorata, Lantana camara and Mikania micrantha) were among the 100 of the world’s worst invasive alien species. C. odorata was found to be the most frequent IAPS with the highest cover. The frequency and cover of the IAPS were higher at the sites close to the settlements than at the sites away from the settlements. The species richness of the IAPS was also higher at the sites closer to the settlements than away. The sapling density of the tree species was found to have declined with the increasing cover of the IAPS suggesting that the IAPS had negatively affected tree regeneration. Our data revealed that the PNP has already witnessed massive plant invasions with widespread occurrence of three of the world’s worst invasive species. Therefore, it is high time to integrate management of invasive alien species in the management plan of the park.

Invasive alien species (IAS) influence the trophic organisation and food web structure in an invaded ecosystem, and therefore, it is imperative to quantify the resultant ecological impacts. The globally recognised ecosystem modelling platform, Ecopath with Ecosim, was used to delineate the impacts of IAS on a tropical freshwater pond ecosystem in India. We analysed the trophic interactions, consumption patterns, prey overlap and mixed trophic impacts of three co-existing invasive alien fish species, African catfish (Clarias gariepinus), suckermouth catfish (Pterygoplichthys pardalis) and Mozambique tilapia (Oreochromis mossambicus), on other functional groups in the ecosystem. Together, the three IAS shared 11% of the total energy consumption and about 50% of the energy consumption by the fish species/groups. There was no predation mortality for African catfish and suckermouth catfish, and a very low estimate for the same was recorded for tilapia (0.64year-1). The IAS shared high mean prey overlap with the native fish groups (Garra sp., Etroplus suratensis, Systomus sarana, Chanda nama and various small species of the cypriniform genera Puntius, Rasbora and Devario) indicating a substantial competition between alien and native species in the ecosystem. Consequently, the three IAS exhibited higher mean negative mixed trophic impacts on these functional groups. A very high Finn's cycling index (39.59%), a low relative ascendency (28.5%) and a very low system robustness (0.07) were observed compared to similar ecosystems, and the baseline values. These indices exposed the vulnerability of the ecosystem towards perturbations, which could be due to the presence of multiple alien invasive species. Mitigating the impacts of IAS should involve a combination of approaches, including eradication through draining and harvesting, high-density stocking of similar trophic level fish in the pond, and local and national level policy interventions.

Invasive alien plant species: From the molecular to the economic approach Invasive alien species (IAS) are plants, animals, pathogens and other organisms that are not natural in a certain ecosystem and that can cause economic or environmental damage or adversely affect human health (Ljubojevićet al., 2022) . Plant invasiveness is a globally recognized environmental and economic problem (Bang et al., 2022) . Today, the loss of biodiversity occurs due to intensive anthropogenic activities, like over-exploitation of species, urbanization and industrialization, environmental pollution, land-use shift, the introduction of IAS as well as climate change (Ren and Duan, 2017) . IAS introduction has many advantages and disadvantages, leading to numerous ecosystem services and disservices. Fostered by climate changes (Kariyawasam et al., 2019) and inherited (inner) ability to adapt to various conditions, IAS treat to suppress natural vegetation. Theoharides and Dukes (2007) defined four main stages of invasion: introduction, naturalization, colonization, and dispersal. Milanovićet al. (2020) stated that alien (especially invasive) plant species differ from native species in different morphological characteristics such as specific leaf area, height, seed size or flowering duration, where invasive species showed significant dominance in the investigated characteristics. A list of invasion-promoting traits is being amended as novel research is being conducted, from seed characteristics (Ljubojevićet al., 2021) to the whole-plant level (Bajwa et al., 2016) . With such high adaptive potential alien species develop traits that allow them to successfully cope with the changes in climate or habitats (Dukes and Mooney, 1999) . However, being very adaptive, fast-growing, and not infrequently highly ornamental, those species provide numerous ecosystem services. If viewed exclusively as 'weeds' then many resources would be invested in the eradication measures of invasive alien species, with little certainty about the desired outcome. Thus, this Research Topic gathered recent findings from around the world, providing insight into differences in gene expression, morphology, physiology and resource utilization by invasive alien species, that provided them with successful habitat invasion. As shown by (Nunes et al.) weedy invaders spread rapidly due to successful adaptation and naturalization, affecting both natural and agricultural ecosystems. One of the most invasive weed species in the sub-tropical and continental climate is Arundo donax L. from Poaceae family. Owing to the chemical and histological modifications, this species successfully inhabit the Mediterranean basin. Another invasion pathway includes soil Frontiers in Plant Science frontiersin.org 01