Our understanding of the diversity and distribution of living things is crucial to the conservation and sustainable use of biodiversity. Because biological invasions by alien species pose a significant threat to native biodiversity, tracking alien species at various geographical scales has recently gained prominence. The current study is designed to evaluate the diversity and composition of invasive plants in different habitats of Mandi Bahuddin, Punjab, Pakistan. The investigation explores the impact of environmental factors on the distribution of alien species in association with edaphic and geographic patterns. Diversity patterns, ecological impact, and the distribution of alien species with respect to environmental variables were recorded. A randomized sampling technique was used taking data from 120 sites with triplet quadrates in each, 360 overall, between 2019 and 2021 to record the data on alien flora and associated environmental variables. Important value indices for each alien species were determined with respect to environmental data, by cluster and ordination analysis. Overall, 43 invasive alien plants from 37 genera and 18 families were documented in the district Mandi Bahuddin. The prominent family was Poaceae with ten species (23.25%) followed by Leguuminosae with six species (13.95%), Compositae with five species (11.62%), Amaranthaceae with three species (6.97%), and Convolvulaceae, Euphorbiaceae, Malvaceae, Polygonaceae, and Scrophulariaceae with two species each (4.65%). Out of 65 alien species comprised herbs 52.13%, grasses 23.25%, shrubs 9.30%, and trees 9.30%. In case life form Therophyte (48.83%) was leading, followed by Chamaephyte with (16.27%) species, Nanophanerophyte and Megaphanerophyte with (11.62%) species each, Geophyte with (6.97%) species, and Hemicryptophyte with (4.65%) species. With leaf size spectra, microphylls (41.86%) were dominating and followed by mesophylls (27.90%), leptophylls (13.95%), nanophylls (11.62%), and macrophylls (4.65%). PCA was applied in order to further understand the species distribution and abundance pattern and to find significant connections among the species with sampling locations comprising various habitats. Ward’s agglomerative clustering technique classified the one hundred and twenty transects into four major groups. Ordination analysis showed that different ecological factors had a significant (p ≤ 0.002) influence on vegetation. The current study provides a foundation from which to comprehend the influences of environmental variables on alien plants’ composition, diversity, structure, and links. These will be useful for developing scientifically informed management strategies for use by administrative agencies in the ecological restoration of the degraded habitat of the studied area.

Salinity stress is one of the primary abiotic stresses limiting crop growth and yield. Plants respond to salinity stress with several morphophysiological, molecular, and biochemical mechanisms, however, these mechanisms need to be improved further to cope with salt stress effectively. In this regard, the use of plant growth-promoting (PGP) and halotolerant bacteria is thought to be very efficient for enhancing growth and salinity tolerance in plants. The current study aims to assess Bacillus safensis PM22 for its ability to promote plant growth and resistance to salt. The PM22 produced substantial amounts of exopolysaccharides, indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylic acid deaminase (ACC-deaminase) under saline conditions. Additionally, inoculation of the halotolerant bacteria PM22 reduced the severity of salinity stress in plants and increased root and shoot length at various salt concentrations (0, 180, 240, and 300 mM). Furthermore, PM22-inoculated plants showed markedly enhanced photosynthetic pigment, carotenoid, leaf relative water content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity, salt tolerance index, total soluble sugar, total protein, and ascorbic acid contents compared to non-inoculated control maize plants. PM22 substantially increased antioxidant (enzymatic and non-enzymatic) activities in maize plants, including ascorbate peroxidase, peroxidase, superoxide dismutase, catalase, total flavonoid, and phenol levels. Maize plants inoculated with PM22 also exhibited a significant reduction in electrolyte leakage, hydrogen peroxide, malondialdehyde, glycine betaine, and proline contents compared to non-inoculated control plants. These physiological appearances were further validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), which revealed the upregulation of expression in genes responsible for stress tolerance. In the current investigation, Bacillus safensis PM22 showed plant growth-promoting and salt tolerance attributes and can be utilized as a bio-inoculant to improve yield in salt stress affected areas.

Xanthium strumarium L. is a globally successful invasive herb that has had significant negative ecological, economic and social impacts in many world regions. The present study was therefore conducted to evaluate the invasive potential and spatial distribution patterns of X. strumarium in heavily invaded plant communities of the semiarid regions of northern Pakistan. Investigations were based on data from 20 plants grown in the Herbarium at the University of Malakand, and from observations in 450 plots distributed across 45 stands representing habitats across Northern Province including open fields, hillocks and abandoned areas in both urban and rural areas. Multivariate analysis identified elevation, organic matter and organic carbon as the environmental variables most associated with communities invaded by X. strumarium. Increased soil silt was positively associated and available water was negatively associated with X. strumarium–invaded communities. These key environmental characteristics allowed us to identify four main associations: Group I: X. strumarium-C. sativa, Group II: X. strumarium-P. hysterophorus, Group III: X. strumarium-A. aspera and Group IV: X. strumarium-C. sativa. Other invasive species were observed, either exotic, such as P. hysterophorus, or indigenous, such as C. sativa and D. inoxia, often co-occurring and responding similarly to these factors. The results suggest that high temperature with drought stress could be a determinant of increasing population at lower elevations, whereas colder climates with adequate moisture are related to reduced populations at higher elevations, near the species’ upper range limits. It is recommend that the inclusion of appropriate, additional soil and climatic variables in species distribution models be implemented in order to better explain species’ ecological niches and help guide conservation and protection plans for native plant communities.

The forest ecosystem has understory vegetation that plays a vital role in sustaining diversity, providing nutrients, and forming a useful association for developing a balanced ecosystem. The current study provides detailed insights into the plant biodiversity and species classification of the understory vegetation of Swat, Pakistan. The floral diversity of the area was comprised of 58 plant species belonging to 32 families. The physiognomy of the studied area was dominated by herbaceous growth form with 47 species. The dominant life-form class was hemicryptophytes with 19 species (33%), followed by nanophanerophytes with 15 species (26%) and therophytes with 13 species (22%). Of the 58 species, 43 plant species were associated with group III clustered by applying Ward’s agglomerative clustering that indicated wide sociability of the species in the studied oak-dominated forests. Group III had higher species richness (10.3), α-diversity (2.74) and β-diversity (9.85), and Margalef index values (3.95). While the group I had maximum Pielous and Simpson index values of 0.97 and 7.13, respectively. Redundancy analysis revealed that seven variables (i.e., latitude, elevation, clay, wilting point, bulk density, saturation, and electric conductivity) were significantly influential concerning the understory vegetation of oak-dominated forests. The understory vegetation of these forests plays an important role in the forest ecosystem of the region. The present study reveals floral divergence and physiognomic scenario of the unexplored study area, which could be an important reference for future ethnobotanical, phytosociological, and conservational endeavors. Moreover, this information is important to the success of efforts intended to prevent the loss of species diversity in these forests by destroying their natural habitats.