Spatial and seasonal distribution patterns of wild shrub vegetation along abiotic gradients in Jhelum District, Punjab, Pakistan

The spatial (habitat-based) and seasonal (phenological) distribution patterns of wild shrub vegetation in Jhelum District, Punjab, Pakistan, are significantly influenced by various abiotic factors. This study aimed to investigate the taxonomic richness, distribution patterns of shrubs in relation to habitat characteristics and environmental gradients in the Jhelum district. Field surveys were conducted from 2019 to 2021 using 120 randomly established transects, and vegetation data were analyzed using classification and ordination approaches. The study area was found to have 28 species of shrubs that constituted 15 families. The dominant families were Solanaceae (17.86%), followed by Apocynaceae and Leguminosae (14.29%). Nanophanerophyte (89.29%) was the dominant life form, followed by Chamaeophyte (7.14%) and Megaphanerophyte (3.57%). In Leaf size spectra Mesophyll (28.57%) then Nanophyll (25%). Phenology of most of the shrubs observed in August-September (25.00 percent) and then March-April (21.43%). The ecosystems characterized with the high levels of species diversity (∼27 species), richness (H' = 3.26; d = 7.67) were those of forest and hilly areas, whereas agricultural lands and home gardens had the lowest diversity levels (less than five species; H' = 1.10; d = 1.82). Hierarchical Cluster Analysis (HCA) indicated three big ecological clusters, i.e., Cluster 1- Dry and arid species ( Fagonia indica, Capparis decidua ), Cluster 2- Moisture-dependent and disturbed habitat species ( Ipomoea carnea, Lantana camara ), and Cluster 3- Forest and hilly region species (Datura metel, Dodonaea viscosa), associated with shaded, stable microclimates. Climatic constraints were reflected in flowering which was highest in spring and monsoon and less in winter and summer. The first two principal components explained 43.39% of the total variation, capturing major, though partial, patterns associated with habitat and seasonal characteristics. Diversity indices, including Shannon diversity, Simpson diversity, and richness measures, indicated higher diversity in forest habitats compared with agricultural habitats. These results are relevant to focus on the conservation of forests, their recovery, and afforestation in the urban areas to preserve ecological balance and increase the robustness of the biodiversity to changing climatic conditions.