Forest canopy resists plant invasions: a case study of Chromolaena odorata in Sal (Shorea robusta) forests of Nepal

Invasive alien species are a major threat to global biodiversity due to the tremendous ecological and economic damage they cause in forestry, agriculture, wetlands, and pastoral resources. Understanding the spatial pattern of invasive alien species and disentangling the biophysical drivers of invasion at the forest stand level is essential for managing forest ecosystems and the wider landscape. However, forest-level and species-specific information on Invasive Alien Plant Species (IAPS) abundance and their spatial extent are largely lacking. In this context, we analysed the cover of one of the world’s worst invasive plants, Chromolaena odorata, in Sal (Shorea robusta) forest in central Nepal. Vegetation was sampled in four community forests using 0.01 ha square quadrats, covering the forest edge to the interior. C. odorata cover, floral richness, tree density, forest canopy cover, shrub cover, tree basal area, and disturbances were measured in each plot. We also explored forest and IAPS management practices in community forests. C. odorata cover was negatively correlated with forest canopy cover, distance to the road, angle of slope, and shrub cover. Tree canopy cover had the largest effect on C. odorata cover. No pattern of C. odorata cover was seen along native species richness gradients. In conclusion, forest canopy cover is the overriding biotic covariate suppressing C. odorata cover in Sal forests.

Alien flora of Oman: invasion status, taxonomic composition, habitats, origin, and pathways of introduction

We present the first inventory and status assessment of the alien flora of Oman, mainly based on field data collected from 1998 to 2021. The study provides (i) a comprehensive account of alien vascular plant species occurring in the wild in Oman, with information on their taxonomic composition. For each species information is given on (ii) invasion status (casual, naturalized or invasive), biogeography, habitat and life-form characteristics, and pathways of introduction. Further, we (iii) explain the differences in the alien species composition in different parts of the country, and (iv) analyse the drivers of plant invasions in Oman. Out of the 111 alien species reported (7.7% of the total Oman vascular flora), 34 species are casuals and 77 naturalized; of the latter seven are considered invasive. The moderate number of alien plant species is likely a result of the country’s arid climate, with extremely high summer temperatures and low annual precipitation in most of its area, and the relatively long isolation of the country. The families richest in alien plant species are Fabaceae (17 species), Asteraceae (14 species) and Poaceae (12 species). More alien plants were found in northern Oman (82 species) than in southern Oman (60 species), and very few species are recorded from the central desert (7 species). The main habitats colonized were man-made habitats, either ruderal or agricultural. Most species alien to Oman are native to South America (49 species) or North America (43 species). This inventory provides a knowledge base for developing a national management strategy for alien vascular plants in Oman.

New record of an alien plant, Petrorhagia nanteuilii (Caryophyllaceae) in Korea

Petrorhagia nanteuilii (Burnat) P. W. Ball & Heywood (Caryophyllaceae), native to western Europe and western North Africa and an introduced or alien plant in South America, Australia, and Japan, was newly found in Gyeongsangnam-do, Korea. Petrorhagia is clearly distinguished from other genera by a bract at the base of calyx, which differs from Gypsophila L., and commissures at the sepals, which is different from Dianthus</i L. Petrorhagia nanteuilii grows on slopes and roadsides, suggesting that it is likely to have been introduced through the installation of green sites and road construction. A precise description, illustration, photographs, and a key to related genera and species is provided.

Avifaunal Diversity of Barandabhar Corridor Forest, Chitwan, Nepal

The main aim of the study was to analyze the avifaunal diversity of Chitwan, Nepal. The avifaunal diversity at six transects of Barandabhar Corridor Forest in Chitwan district was carried out during two visits (autumn and spring) in 2020-2021. The line transect method was used to cover most of the study area. In total, 125 species of birds representing 18 orders and 59 families were recorded. The highest number of bird species i.e. (56) 44.8% were represented by order Passeriformes along with 34 families. The highest number of species was found in family Picidae (9) 7.2% followed by Cuculidae (8) 6.4% and least number (1) 0.8% in other 31 families. The seasonal status of species was Autumn (84) and Spring (116). The relative abundance of species was Very Common (60), Common (40), Uncommon (16), and Rare (9). According to the National Red List of Nepal’s Birds, 110 species were in the Least Concern category, eight species were in the Near Threatened category, six species were in the Vulnerable category and one species was in the Critically Endangered category. It was noted that major threats to the birds were illegal fishing, noise pollution, firewood collection, illegal cattle grazing, and invasive alien plant species. One Globally Threatened Bird Lesser Adjutant Leptoptilos javanicus was also noted.

Diversity of vascular plants and zooplankton communities in regard to the ecological assessment of the territory of the ecological park “Samara Venice”, Samara Region, Russia

The results of the floristic and hydrobiological studies performed in May - August 2020 on the territory of the ecological park Samara Venice (Samara Region, Russia) are presented. These data form the basis for the ecological assessment of the territory. The diversity of vascular plants is presented by 4 divisions, 65 families, 205 genera, and 309 species. Among them, 66 species (21.4%) belong to the alien plant species, including nine invasive. Habitats of the plants included in the regional Red List are found. The zooplankton diversity comprises 60 species and morphs. The zooplankton community has undergone significant transformation, manifesting by an increase in the total biomass and in the biomass of crustaceans and rotifers, and by a decrease in absolute and relative species richness. It is revealed that a number of the studied water bodies belong to the transitional type, and may be characterized as of middle position between the meso- to eutrophic type (moderately polluted and polluted waters).

Screening of Xanthium strumarium (IAPS) Growing on Abandoned Habitats in Khyber Pakhtunkhwa, Pakistan: Perspectives for Phytoremediation

The ecological impacts of invasive alien plant species (IAPS) are well-documented, but a dearth of studies exist concerning its economic, livelihood, biotechnological, and health risk assessment perspectives. IAPS management is currently expanding to ecological indicator and biotechnological aspects. Hence, this study aimed to investigate the phytoremediation potential, biomedical, and bio-safety applications of X. strumarium growing in different abandoned habitats in Khyber Pakhtunkhwa, Pakistan. In this study, 45 plants and soil samples were gathered from 15 abandoned sites and analyzed for Pb, Cd, Cu, and Zn concentrations; bioaccumulation (BA); and translocation factor (TF). The assayed Pb and Cd concentration was higher and above threshold in both soil–plant samples. BAF was found higher in roots than intact plants despite having a significant accumulation of Cd, Pb, and Zn, which shows high metals tolerance of this IAPS. PCA-ordination explained a high cumulative variance (98.9%) and separated roads and densely populated sites with comparatively high metals concentration, indicating the pseudometallophyte nature of X. strumarium. Soil, sand, and plant biomass were shown to be the major determinants affecting the heavy metals concentration and its phytoremediation significantly, which may be due to the soil’s metalliferous nature in the study area. This IAPS exhibited strong translocation and hyperaccumulation capacity in different functional traits with comparatively high Pb, Cd, and Zn (≥1 TF) mobility and, hence, can effectively be used for Pb phytoextraction and phytostabilization of Cd, Cu, and Zn, respectively. Likewise, several other non-spontaneous IAPS growing on such abandoned habitats might be promising for developing a reasonable strategic framework for heavy metals mitigation and health risk implications in this region.

Invasive alien plant species in Romania of European Union concern

An assessement of the alien plants of Romania was conducted which considered the requirements of Regulation 1143/2014 of the European Union (EU). Thus, available data about the presence, invasiveness, distribution, pathways of introduction and their known impact in the territory of Romania were analysed. We found that of 36 plant species of EU concern, four are already established in Romania and widespread, at least locally or regionally: Ailanthus altissima, Asclepias syriaca, Elodea nuttallii and Impatiens glandulifera. For Humulus scandens there are some reports, but its presence and status require confirmation. Heracleum sosnowskyi and Ludwigia peploides are confirmed for only one location for each species. The presence of Cabomba caroliniana and Myriophyllum aquaticum in Romania is not confirmed. Most of the records are intentional introductions for ornamental purposes. Regarding their invasiveness, given the geographical origin and history of invasion in warmer climate regions (e.g., tropical, subtropical), many of the species listed as being of EU concern do not currently constitute a real threat to Romania, for the time being, but may do in a climate change scenario for the 2070s. Data about the impact of alien plant species and their management in Romania are scattered or completely missing. Coordinated institutional efforts are needed to increase the efficiency of the management of alien species at national and local level. These efforts should include: enhancing the legislation and the capacity of public institutions to manage invasive species, increasing the research interest in the science of this topic and promoting real measures to mitigate, control and remove alien plants.