Distribution pattern, population structure and habitat geography of Betula utilis subalpine forests of Kashmir region in the western Himalayas: implications for conservation and sustainable management

Betula utilis is the keystone tree species constituting the basic structure of the western Himalayan subalpine forests in Kashmir regions. It is endemic to Himalayan region, and performs dynamic ecological functions. Betula utilis populations in the region are threatened due to immense anthropogenic disturbances. There is little information available regarding the status of Betula populations in the region indicating acknowledge gap. This study investigated the distribution patterns, population structure, floristic diversity and phytosociological attributes of Betula forests, threats, as well as evaluating the habitat geography of the species using GIS analysis. Systematic quadrat-based sampling was used to record primary vegetation data and geographic attributes from a total of 30 subalpine forest sites in mountainous areas in an elevational range of 2800–3800 m. Betula utilis populations in the region were characterized with a stem density of 739.33 trees/ha with a basal area cover of 1974.93 m²/ha. The Betula papulations exhibited a regeneration potential of 609.33 seedlings/ha. A deforestation intensity of 351.33 Betula stumps/ha was recorded at the investigated sites. Floristic inventory revealed a total of 226 plant species recorded as associated flora in the Betula forest, belonging to 139 genera and 58 families. Communities exhibited moderate levels of diversity and richness having average values of Simpson's diversity index as 0.94; Shannon Wiener index as 3.22, species richness as 1.68, species evenness as 0.90, and community maturity index as 30.47. Biological spectrum analysis revealed Hemicryptophytes were the dominant life form whereas microphylls were the dominant leaf size class. ARC-GIS analysis significantly explained the habitat geography of the Betula populations. Digital elevation Model developed from SRTM dataset revealed that B. utilis populations were distributed in an altitudinal range of 2800–3800 m. North facing slopes with high degree of slope steepness were identified as the key habitats of the B. utilis populations. Fuelwood and timber extraction, and overgrazing were identified as major threats to the highly fragmented Betula populations in the region. Prevailing threats have significantly reduced B. utilis habitat, leading to a rapid decline in the species distribution range. It is recommended to formulate effective conservation measures such as community-based conservation initiatives, integrative sustainable harvesting policies, habitat restoration programmes, and promoting alternative livelihoods that support local communities to safeguard the Betula forests in the Himalayan region of Kashmir.