SUMMARY
Understanding the pattern of variation in adaptive traits of rare and endemic species along environmental gradient can suggest important implications for developing optimal strategies for species conservation and sustainable management. In this studywe aimed to study variation in life-history traits of an endemic species M. napaulensis DC. along an elevation gradient in Langtang National Park, Central Nepal covering three populations. Each population was investigated two times (2013 and 2014) covering different seasons. Population sampling was made to read habitat during the peak growing period (during monsoon) except seed output, which was studied during the late growing period (post monsoon). Entire area of each population was extensively surveyed to record all the individuals, including plants in flowering or fruiting and their detailed vegetative characteristics and traits related to population fitness. Analysis of the habitat features showed that M. napaulensis exhibited high habitat specificity. M. napaulensis was restricted to open and rocky habitats of high altitudes. M. napaulensis growing sites had low vegetation cover indicating decreased interspecific competition. M. napaulensis showed high variation in traits due to altitudinal variation, climatic conditions, and disturbances. Specifically, reproductive traits discriminated the populations. M. napaulensis was suffered from human disturbance mainly from livestock grazing, plant harvesting, and garbage pollution as the study area is an important tourist destination and pilgrimage site. Conservation of rare and endemic species such as M. napaulensis requires strong provisions restricting human activities and minimizing the impact of harvesting and grazing; and implementing habitat restoration and population augmentation programs.