Plant trait approach to assess the vulnerability of Rhododendron arboreum in western Himalayas

Climate change is profoundly impacting Himalayan ecosystems, with substantial challenges to keystone species like Rhododendron arboreum. Present study attempted to investigate R. arboreum response to varying environmental conditions at altitudes between 1500 to 3000 m in three western Himalayan temperate forests, through evaluating plant functional traits. IPCC's internal vulnerability framework, characterised by two dimensions: sensitivity and adaptive capacity was applied. Structural Equation Modelling (SEM) was applied to elucidate the relationship between traits and the dimensions. Sensitivity was analysed using sub components like Light Harvesting, Nutrient and Gas Fluxes, while adaptive capacity by Resource Efficiency, Architecture and Defence, Resource Limitation and Resource Facilitation. The results revealed high sensitivity (0.64) in moru oak forests, high adaptive capacity in moist temperate deciduous forests (0.59), and high vulnerability in ban oak forests (0.54). SEM Models for sensitivity and adaptive capacity were significant. Sensitivity exhibited positively significant influence of Nutrient and Gas Fluxes with path coefficient of 1.07 and 0.80, respectively. Adaptive capacity showed a positive relationship with the Resource Limitation and Architecture and Defence, while a negative relationship with Resource Facilitation, with a path coefficient of 0.94, 0.42 and -0.11, respectively. Overall, the vulnerability of R. arboreum to environmental changes is shaped by a complex interplay of physical characteristics (morphological), biological functions (physiological), and interactions with surroundings (ecological). These insights underscore the importance of understanding trait vulnerability dynamics for effective forest management strategies amidst changing environmental conditions.