ECOLOGICAL PATTERNS OF QUERCUS SPECIES ALONG ENVIRONMENTAL GRADIENTS IN THE WESTERN HIMALAYA, PAKISTAN - Mustajab Ahmed; Zafar Iqbal; Ghulam Mujtaba Shah; Bakhti Alam; Saeed Ahmad Asad (Journal of Animal and Plant Sciences, 2026)
Himalaya is one of the global biodiversity hotspots and hosts a complex mountain ecosystem due to high topographic and climatic heterogeneity, yet its forests are under constant pressure from climate change and human-driven disturbances. In this study, we examined the distribution, community structure, and ecological factors affecting Quercus-dominating forests in the Hazara Division, Pakistan. A total of 98 sites were sampled using the quadrat method to assess plant associations and species composition. Quadrat sizes were 10 × 10 m2 for trees, 5 × 5 m2 for shrubs, and 1 × 1 m2 for herbs. A total of 180 plant species belonging to 142 genera and 65 families were recorded. Quercus species showed clear elevational stratification with Q. glauca dominant at low elevation of 942 meters above sea level (MASL), Q. baloot and Q. dilatata at mid elevation (1123-2423 MASL), while Q. semecarpifolia at high altitude (2687-3306 MASL). Cluster analysis revealed 6 assemblages of communities: Quercus incana-Asparagus officinalis-Avena fatua community (QAA), Quercus incana-Aesculus indica-Phragmites communis community (QAP), Quercus semecarpifolia-Bergenia stracheyi- Indigofera heterantha community (QBI), Quercus dilatata-Cannabis sativa-Quercus glauca community (QCQ), Quercus incana-Prunus vulgaris-Quercus dilatata community (QPQ), and Quercus baloot-Quercus dilatata-Cynodon dactylon community (QQC). Highest diversity (richness=22.3) was recorded in the QQC community at mid elevation with Shannon index (2,78), and the lowest diversity (13.8) was found in the QBI community at high elevation (H=2.37). Multivariate analyses showed that temperature (r2=0.25), relative humidity (r2=0.14), and altitude (r2=0.5) were the most important climatic and geographic factors determining species distribution. Q. semecarpifolia and Q. glauca showed a poison model with the environmental variable, while other species exhibited a negative binomial model in response to environmental gradients. This study provides baseline strategies for the preservation and conservation of Quercus species under climatic and anthropogenic pressures and supports the development of effective management strategies in the western Himalayan forests in the Hazara division of Pakistan.
Keywords: journal article; Quercus; Distribution; Community structure; Multivariate analyses; Species richness; Environmental variables