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A surprisingly large number of species potentially threatened by human harvest lack quantitative ecological studies incorporating harvest effects, especially clonal species in the alpine Himalayas. We studied density and biomass variation of a threatened medicinal herb, Neopicrorhiza scrophulariiflora, to examine the effect of harvest on plant performance. The study covered two regions with contrasting harvest situations—one with open‐access and another protected from commercial harvesting. Four populations from each region were compared along an elevation gradient (3,800–4,800 m). Also, we conducted in situ interviews with 165 and 38 medicinal and aromatic plant users in open‐access and protected regions, respectively, to assess the collection and use patterns of the target species. The quantity harvested per household for traditional healthcare use was similar in both regions. We found no evidence of trade‐driven collection in the protected region but in the open‐access region a trade‐based annual collection of 35–465 kg dried rhizomes per household had a strong negative effect on both density and biomass. In the protected region, the effect of harvest intensity on plant density was positive for vegetative and negative for reproductive individuals, whereas in the open‐access region, the effect was negative for both vegetative and reproductive individuals. The results indicated that a low harvest intensity had no adverse impact on N. scrophulariiflora populations; however, quantification of the optimum level of harvest remains to be explored. Shrub vegetation appeared to buffer the harvest impact on plant density, possibly through the retention of additional moisture. To maintain population viability, we suggest regulating harvest, for example, by introducing rotational harvest systems, ensuring that a sufficient number of reproductive individuals are left as a source of propagules in each harvested population and that populations are given time to recover between harvests. A surprisingly large number of species potentially threatened by human harvest lack quantitative ecological studies incorporating harvest effects, especially clonal species in the alpine Himalayas. We studied density and biomass variation of a threatened medicinal herb, Neopicrorhiza scrophulariiflora, to examine the effect of harvest on plant performance. The study covered two regions with contrasting harvest situations—one with open‐access and another protected from commercial harvesting. Four populations from each region were compared along an elevation gradient (3,800–4,800 m). Also, we conducted in situ interviews with 165 and 38 medicinal and aromatic plant users in open‐access and protected regions, respectively, to assess the collection and use patterns of the target species. The quantity harvested per household for traditional healthcare use was similar in both regions. We found no evidence of trade‐driven collection in the protected region but in the open‐access region a trade‐based annual collection of 35–465 kg dried rhizomes per household had a strong negative effect on both density and biomass. In the protected region, the effect of harvest intensity on plant density was positive for vegetative and negative for reproductive individuals, whereas in the open‐access region, the effect was negative for both vegetative and reproductive individuals. The results indicated that a low harvest intensity had no adverse impact on N. scrophulariiflora populations; however, quantification of the optimum level of harvest remains to be explored. Shrub vegetation appeared to buffer the harvest impact on plant density, possibly through the retention of additional moisture. To maintain population viability, we suggest regulating harvest, for example, by introducing rotational harvest systems, ensuring that a sufficient number of reproductive individuals are left as a source of propagules in each harvested population and that populations are given time to recover between harvests.

Understanding the causes of rarity has become increasingly important for the conservation and management of plant species. In this study, we compared spatial distribution, habitat characteristics, and population size and structure of two closely related species of poppy occurring in the Himalaya, the rare and endemic Meconopsis napaulensis and the widespread common congener M. paniculata in order to explain the causes of rarity of the former species. This study was carried out in Langtang National Park, north-central Nepal covering six populations of M. napaulensis and four populations of M. paniculata . Analysis of the habitat features revealed greater tendency of M. napaulensis to exhibit high habitat specificity. It was restricted to nutrient-poor, open and rocky habitats at >3700 m asl. Sites where M. paniculata were sampled showed high variability in terms of edaphic and topographic features. Mean ‘area of occupancy’ tended to be high for M. paniculata compared to M. napaulensis. M. paniculata showed larger population size and greater abundance as compared to M. napaulensis . The poor representation of younger life stages in M. napaulensis despite high proportion of reproductive adults indicated lower recruitment potential. The present study has illustrated that the rarity of M. napaulensis is strongly related to a combination of ecological and geographical constraints, which prevent reproduction, dispersal and colonization. It further demonstrates that the maintenance of population size of rare species largely depends on the survival and abundance of plants of younger stages. Thus, management directed towards reducing the impact on plants of young stages and protecting reproductive individuals from flower and fruit harvesting would help to maintain population size. Finally, development of action plans and guidelines incorporating scientific findings and accommodating local peoples’ socio-economic and cultural factors associated with the extinction risks is imperative for the conservation of rare and endemic species. doi: http://dx.doi.org/10.3126/botor.v8i0.5959 Botanica Orientalis – Journal of Plant Science (2011) 8: 57-69