Ageratina adenophora and Lantana camara in Kailash Sacred Landscape, India: Current distribution and future climatic scenarios through modeling.

Invasion of alien species in high altitude ecosystems is a potent threat to the species diversity as well as it can cause severe environmental and economic issues. The invasion of alien plant species can be facilitated by many eco-climatic factors. The present study was conducted to assess patterns and trends of invasion by Ageratina adenophora in major land use and land cover types; in Gokerneshwergad watershed of Kailash Sacred Landscape (KSL) in western Himalaya. Extensive surveys were conducted to map the species in each season and habitat type. Sites with high biotic pressure and open forest canopy were the most suitable habitats for its growth. A negative correlation was found between distribution and altitude. The highest invasion was recorded in between 1700 – 1800m elevation gradient, between 20° and 30° slope positions and at North (33.33%), whereas, the lowest invasion was recorded between 700 – 800m in South-East directions (3.70%). Several other parameters such as distance from the disturbance site such as road, villages or settlements, drainage and soil texture were also found to be affecting the distribution pattern of this species. Interestingly results reveal that the alien plants also start competing among themselves after reaching their threshold level.

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

Invasive alien plant species (IAPS) can pose severe threats to biodiversity and stability of native ecosystems, therefore, predicting the distribution of the IAPS plays a crucial role in effective planning and management of ecosystems. In the present study, we use Maximum Entropy (MaxEnt) modelling approach to predict the potential of distribution of eleven IAPS under future climatic conditions under RCP 2.6 and RCP 8.5 in part of Kailash sacred landscape region in Western Himalaya. Based on the model predictions, distribution of most of these invasive plants is expected to expand under future climatic scenarios, which might pose a serious threat to the native ecosystems through competition for resources in the study area. Native scrublands and subtropical needle-leaved forests will be the most affected ecosystems by the expansion of these IAPS. The present study is first of its kind in the Kailash Sacred Landscape in the field of invasive plants and the predictions of potential distribution under future climatic conditions from our study could help decision makers in planning and managing these forest ecosystems effectively.

Introduction: Climate change and invasive alien plant species (IAPS) severely threaten natural ecosystems globally. Objective: To identify and assess climate suitability for seven wetland-associated species and predict their future distribution using shared socio-economic pathways (SSPs) 2 4.5 and 5 8.5 for 2050 and 2070. Methods: The species selected were Alstonia macrophylla, Annona glabra, Dillenia suffruticosa, Lantana camara, Leucaena leucocephala, Panicun maximum, and Sphagneticola trilobata. Data on species occurrence were collected by field surveys in the Western province (Colombo, Gampaha and Kalutara districts), and this, together with climate data, were fed into the Maximum Entropy model (MaxEat model). Climate suitability area maps were developed for the seven IAPS for the current climate and four future scenarios. Results: A. glabra, L. camara, and L. leucocephala showed an increase in climate-suitable areas for the years 2050 and 2070 under both climatic scenarios compared to the current distribution. S. trilobata showed a decrease in its range in the future compared to the current distribution. The climate-suitable area for A. macrophylla will also not expand under either scenario except for a modest rise in SSP2 4.5 in 2050. The current distribution of D. suffruticosa and SSP2 4.5 in 2050’s distributions were almost identical, and the other two future scenarios showed comparatively low distribution. For P. maximum SSP2 4.5 indicated a slight increase in climate-suitable areas for 2070 compared to the current distribution. Conclusion: A. glabra, L. camara, and L. leucocephala can become highly invasive as their ranges expand in response to future climate changes. The distribution of S. trilobata will be significantly reduced under future climate scenarios. As suitable areas for IAPS increase in the Colombo district over time compared to other districts in the province, its wetland-associated native plant species may face a greater risk of invasion by IAPS in future climatic scenarios.

Methods to reduce the introduction and spread of Invasive Alien Species (IAS) are key to reducing the economic, environmental and social impacts of IAS. IAS propagules can be moved around accidentally on clothing and equipment used in agriculture, transport, trade and recreation. Campaigns to slow the spread of aquatic IAS encourage water users to check, clean and dry their equipment and clothes, using hot water during the cleaning process where feasible. The UK Check Clean Dry biosecurity campaign recommends immersion in hot water (45 °C) for 15 minutes, however, implementation time may be a barrier to adoption of biosecurity practices. Here we aim to refine the advice given and test the efficacy of hot water treatment in actual conditions, with a view to reduce the recommended time to clean equipment while still preventing spread. The effectiveness was tested for a range of temperature (40, 45, 50, 55 and 60 °C) and time (10 seconds, 1, 5, 10, 15 minutes) treatments in killing IAS propagules of two invasive aquatic animal species (Dreissena polymorpha, Dikerogammarus villosus) and two invasive aquatic plant species (Myriophyllum aquaticum, Crassula helmsii), which are of global/national importance. For both invasive animal species, 100% mortality was achieved at all temperature and time treatments. However, plant mortality was affected by both temperature and time, with higher mortality resulting from higher temperatures and exposure times. Immersion for the recommended 15 mins at 45 °C caused complete mortality of C. helmsii, but only 40% mortality of M. aquaticum. Immersion in water at 50 °C or higher led to 100% mortality for C. helmsii and 90% mortality for M. aquatium at shorter treatment durations of 5 or 10 mins. In addition, immersion in water at 60 °C caused 100% mortality after only 1 minute exposure. To ensure adoption and application of biosecurity practices, guidance should be simple, consistent and safe. For practical application in field we recommend, where feasible, immersion of equipment in water at 50 °C for a minimum of 5 minutes to achieve high mortality of IAS propagules.

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

Although climate change may facilitate the spread of invasive alien species (IAS), research assessing this link remains limited. Recognizing suitable habitats where IAS have been introduced is crucial for biodiversity conservation and ecosystem management. Here, we integrated online, museum, and laboratory occurrence databases with local ecological knowledge (LEK) on IAS fishes from semi-structured interviews and georeferenced social network posts from traditional and recreational fishers to model the habitat-suitability of three voracious IAS Cichlids introduced in the Brazilian part of the Upper Paraguay River Basin (the Pantanal wetland and its tributaries). Our goal was to locate areas (regions, sub-basins, and reservoirs) most at risk from the spread of these IAS fishes in the basin. The findings reveal extensive suitable habitats for these IAS fishes throughout the study basin, currently covering half of the Pantanal wetland and up to 90% of the upstream sub-basins. Under future climate scenarios, these suitable habitats are projected to expand further, encompassing almost the entire Pantanal floodplain. These results highlight a potential IAS Cichlid range expansion in the Pantanal floodplains in the upcoming decades, correlating with common climate change forecasts. We also emphasize the value of integrating ecological niche models (ENMs) along with Citizen Science data to identify high-risk areas during early invasion stages, inform preventive strategies, and support conservation efforts to mitigate the impacts of IAS on native biodiversity.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-30425-3.

Climate change is considered a driver for the spread of invasive alien species (IAS); nevertheless, research assessing this link remains limited. Recognizing suitable habitats where IAS have been introduced is crucial for biodiversity conservation and ecosystem management. Here, we integrated online, museum, and laboratory occurrence databases with local ecological knowledge (LEK) on IAS fishes from semi-structured interviews and georeferenced Instagram posts from traditional and recreational fishers to model the habitat-suitability of three voracious IAS Cichlids introduced in the Brazilian part of the Upper Paraguay River Basin (the Pantanal wetland and its tributaries). Our goal was to locate areas (regions, sub-basins, and reservoirs) most at risk from the spread of these IAS fishes in the basin. Our findings reveal extensive suitable habitats for these IAS fishes throughout the study basin, currently covering half of the Pantanal wetland and up to 90% of the upstream sub-basins. Under future climate scenarios, these suitable habitats are projected to expand further, encompassing 85% of the Pantanal floodplain - one of the most fish-rich basins in the Neotropical region (~ 300 spp). These findings underscore a potential IAS Cichlid range expansion in the Pantanal floodplains in the upcoming decades. Our study emphasizes the value of integrating Ecological Niche Models (ENMs) with Citizen Science data to identify high-risk areas during early invasion stages, inform preventive strategies, and support conservation efforts to mitigate the impacts of IAS on native biodiversity.

Some invasive alien species (IAS) may constitute an important threat to global biodiversity due to major ecological impacts. In 2014, the European Union (EU) introduced a regulation (EU) No 1143/201 on the prevention and management of the introduction and spread of IAS. EU member states are required to carry out an analysis of the introduction and spread of potential IAS in their territories. In the case of aquatic alien species, shipping is considered as the main pathway for their introduction. In this study, a horizon-scanning tool was applied for identifying potential aquatic IAS introduced by shipping into the EU Baltic Sea Region (BSR) countries. This tool has mostly been applied on a country level, but it is more reasonable to study the invasive potentiality at a regional scale, especially for aquatic species that generally disperse over long distances. Individual Baltic countries may also benefit from the results of this study. The result of the horizon-scanning method that we applied produced a list of 27 potential aquatic invaders for the EU BSR countries introduced by international marine and inland shipping. In order, Asia (34% of the species), North America (27% of the species), and Indo-Pacific (23% of the species) were the most frequently listed geographical origins of concern. Marine habitat was the most frequent of the potential IAS, accounting for 41% of the species. Fish (26% of the species), Mollusks (18% of the species), and Crustacea (15% of the species) were the most frequent taxonomic groups. The list of potential IAS was prioritized from highest to lowest probability of invasion (establishment, spread, and impact). Eight species reached the highest probability of invasion. One of the potential IAS, Mytilus galloprovincialis, is native to the Mediterranean Region. These results provide valuable information that policy makers can use to develop more efficient prevention strategies for IAS introduced by shipping into the Baltic Sea.

Present study was carried out to understand the proliferation status of invasive alien species (IAS) along altitudinal gradient (650-2150 m) in different forest types (Sal, Pine, Oak and Deodar) of western Himalaya. To understand the trend of proliferation of invasive species repeat vegetation survey and quantitative analysis method used in same plots after two years. Major invasive species in the region were Lantana camara, Ageratina adenophora, Ageratum conyzoides and Parthenium hysterophorus. Ageratina adenophora was highly spreading invasive species present in all forest type of the study area. Maximum density (8394 ind/ha.) and frequency (64.15%) was recorded in Pine forest. Important value index (IVI) of Ageratina adenophora increase from 23.4 to 25.71 in Pine forest followed by in Sal forest (6.32 to 8.21) and Deodar forest (11 to 12.53). Maximum density (246 ind/ha.) and frequency (41%) of Lantana camara recorded in Sal forest and IVI increase from 29.9 to 30.78. Oak forest allowed less rate of invasion of alien species. In study area with increase elevation number of invasive species decrease. However, high proliferation rate of Ageratina adenophora recorded at an elevation 2150 m asl in moist Deodar forest.

Both in Ethiopia and in the countries of East Africa, the continuing proliferation and spread of invasive alien species (IAS) is now recognized as a serious problem, which needs to be addressed. While this situation has improved dramatically over the past 10 years, further progress has been hampered by the absence, hitherto, of a comprehensive IAS database for the region. Countries in the region have repeatedly expressed the need for such a database, as a tool to assist in the identification of naturalized and invasive alien plant species, and in understanding their impacts, both existing and potential, while also providing pointers on what can be done to manage such species. This information is seen as essential, not only in enabling countries to develop effective IAS management strategies, but also in helping them to meet their obligations under various international agreements and treaties, including Article 8 (h) of the Convention on Biological Diversity (CBD) and Target 9 of the 2020 Aichi Biodiversity Targets. In providing such a database, this Guide is intended to give the countries of eastern Africa the information they require, in order to be able to develop effective strategies for combating the growing menace posed by invasive alien plants. It is further hoped that this Guide will foster increased regional collaboration, in responding to the challenges of managing shared invasive plant species. The Guide is based on the findings of extensive roadside surveys, carried out throughout the region, and on a review of the literature pertaining to naturalization and/or invasiveness among alien plants in eastern Africa. By this means, scores of exotic plant species were found to have escaped from cultivation, and to have established populations in the 'wild', to the detriment of natural resources and the millions of people in the region who depend on these resources. Included in the Guide are descriptions of roughly 200 exotic plant species which are either invasive already or which are deemed to have the potential to become invasive in the region. The profiled species include aquatic invasive plants or waterweeds (seven species); vines, creepers or climbers (20 species); terrestrial herbs, shrubs, and succulents (more than 30 species of each), and trees (more than 60 species). Also profiled in this Guide are many exotic plant species which, although their current distribution in the region may still be relatively localized, nevertheless have the potential to become considerably more widespread and problematic. The wide range of habitats and climatic conditions found within Ethiopia and across East Africa make the region as a whole particularly prone to invasions by a host of introduced plant species. Such invasions are being facilitated by increased land degradation, especially through overgrazing and deforestation, and also by climate change.

Invasive alien plant species (IAPS) are considered the second most important agent after habitat destruction for species endangerment and extinction. Though dozens of alien invasive plant species (IAPS) occur in the Indian Himalayan region, information on distribution and perceived impact is lacking in the western Himalaya. In the present study, 701 randomly selected households in 45 villages were surveyed through questionnaire surveys in Chandak-Aunla Ghat (329) and Hat-Kalika (372) watersheds in Kailash Sacred Landscape (KSL-India) to know their view on the issues associated with the IAPS and attitudes towards their management. The knowledge, perception, use and management strategies of different IAPS were analyzed. Only 39% of females and 27% of males had knowledge of IAPS. The highlights of the study are: i) Ageratina adenophora had the highest Relative Frequency of Citation value among 14 major IAPS in the study area, ii) informants of Hat-Kalika showed a low richness of knowledge and sharing with their family members as compared to Chandak-Aunla Ghat, iii) respondents perceived IAPS negatively and rated biological invasion and habitat loss as major environmental problem, iv) the major management strategies identified were restoration, eradication, community education and information, and v) perception and level of knowledge sharing on invasive species among age classes and gender have implications for stakeholders and policymakers in management of IAPS.

The invasion of ecosystems by exotic species has been identified as the second cause of biodiversity loss worldwide, and is one of the most difficult threats to reverse. In Uruguay, the introduction and spread of invasive alien species (IAS) has been identified as a serious environmental problem, becoming perhaps the greatest danger that native forests currently face. IAS often represents optical differences in the forest canopy and can therefore be detected remotely. The two most widespread and aggressive woody IAS in the country's forests are Ligustrum lucidum and Gleditsia triacanthos. The objective of this study was to spatially identify IAS within the native forest of Uruguay, mainly these two species, using remote sensing techniques. This work is based on multispectral data from medium-resolution satellite images (Landsat) and uses the normalized difference fraction index (NDFI) for classification. The NDFI is sensitive to canopy coverage and is calculated through a sub-pixel spectral mixture analysis (SMA), decomposing the reflectance information for each pixel into fractions. The results showed an area of ​​22,009 ha of native forest invaded by these IAS, with an overall accuracy of 87.6%, representing 2.63% of the total native forest area in the country. The results presented in this work will help to geographically analyze the invasion by IAS in the forest, linking it to possible drivers. Furthermore, this map can now be used as relevant information when designing IAS prevention, mitigation, restoration, and eventual eradication strategies in the country.

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.