Ecological assessment of Iris hookeriana across subalpine and alpine regions of the Hindu-Himalaya

Muhammad Shakeel Khan ¹ Shujaul Mulk Khan ^1* Abd Ullah ² Jie Liu ² Zeng-Yuan Wu ² jawad Hussain ¹ Shakil Ahmad zeb ¹ Nazir Mohammad ¹ Zareena Batool ¹ Rabia Afza ³ Zafeer Saqib ⁴ Fazal Manan ¹ Shahab Ali ^1*

• ¹ Quaid-i-Azam University, Islamabad, Pakistan
• ² Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, Yunnan, China
• ³ Hazara University, Dhodial, Khyber Pakhtunkhwa, Pakistan
• ⁴ International Islamic University, Islamabad, Islamabad, Islamabad, Pakistan

The Hindu-Himalayan region, a global biodiversity, hotspot harbors numerus endemic plant species that contribute significantly to ecosystem stability. Among these, Iris hookeriana, an endemic perennial herb, thrives in the subalpine and alpine zones of the Hindu-Himalayas. The study aimed to assess the population dynamics of Iris hookeriana, assesses the primary threats to its survival, and explores its ecological associations with indicator species. Fieldwork was conducted across thirty-five distinct sites, at the elevation range of 2,500 to 3,900 meters above sea level. A random stratified sampling method was employed to assess both qualitative and quantitative plant characteristics. Edaphic, topographic, geographic coordinates, and elevation Global Positioning System (GPS) data were recorded on each sampling site. Plant species associations were analyzed using 5 × 5 m² quadrat for shrubs and 1 × 1 m² quadrat for herbaceous vegetation. The relationships between species composition and environmental variables were analyzed via Statistical analyses, including Detrended Correspondence Analysis (DCA), Canonical Correspondence Analysis (CCA), Two-Way Cluster Analysis (TWCA), and Indicator Species Analysis (ISA), were conducted using PCORD version 5.0. Seventy associated plant species from twenty-six families were identified across thirty-five sampling sites , revealing four major plant associations: (1) Arenaria-Viola association, (2) Nepeta-Oxytropis association, (3) Phlomis-Prunella association, and (4) Bistorta-Carex association. These associations exhibited significant correlations (p < 0.05). The identification of these four novel plant associations provides a crucial baseline for understanding the ecological dynamics of the subalpine and alpine ecosystems. The study emphasizes the significant role of environmental factors i.e., altitude, organic matter, pH, humidity, total dissolved solid, electrical conductivity, nitrogen, phosphorus, silt, and clay content in shaping the Iris hookeriana population within the subalpine and alpine zone of Hindu-Himalayan Mountains. The findings show that indicator species and plant associations vary with changing environmental conditions, providing valuable insights for sustainable biodiversity management in subalpine and alpine ecosystems of the Hindu-Himalayan mountains.