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Impacts of road on plant invasions in the Middle Mountain region of central Nepal

Journal of Mountain Science 2024年第2期21卷 619-632页

作者： Ananda ADHIKARI Adarsha SUBEDI achyut tiwari Bharat Babu SHRESTHA Central Department of Botany Tribhuvan UniversityKirtipur 44618Nepal

Biological invasion is triggered by human development activities such as the construction and expansion of road *** verges serve as important habitats and corridors for the distribution of invasive alien plant species(IAPS)between geographically distant ***,the trajectory of plant invasion and the data regarding the impact of roads on IAPS distribution are relatively poor in ***,we surveyed two road types(main roads and feeder road)in the Middle Mountain region of central Nepal in order to investigate how different road types are driving the dispersal of IAPS along road verges and the adjacent natural *** sampling was conducted at ca 2.5 km intervals along the *** each sampling site,paired plots(25 m×4 m)were sampled:one adjacent to and along the road,and another 20 m away and parallel to it in the interior *** results revealed that the main road verges had a higher cover(33%)and a larger number of IAPS(14 species)than the feeder road(25%;10 species).The IAPS cover and richness were significantly higher along verges than in the adjacent interior habitats for both road types,indicating that roads are contributing as corridors for the dispersal of IAPS in the Middle Mountain areas of central ***,elevation,tree canopy,and disturbances(grazing/mowing/trampling)were found to be the key factors that determine spatial distribution of IAPS along road *** emphasize that regular monitoring of vegetation along the road verges can help with the early detection and control of potential IAPS in the region before they become problematic.

关键词： Biological invasions Dispersal corridor Invasive alien plants Transport infrastructure Himalayan mountains

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Plant endemism in the Nepal Himalayas and phytogeographical implications

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Plant Diversity 2019年第3期41卷 174-182页

作者： achyut tiwari Yadav Uprety Santosh Kumar Rana Department of Botany Tri-Chandra Campus Tribhuvan University Kathmandu Nepal Central Department of Botany Tribhuvan University Kirtipur Kathmandu Nepal Research Centre for Applied Science and Technology Tribhuvan University Kathmandu Nepal IUCN (International Union for Conservation of Nature) Kathmandu Nepal Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 Yunnan China University of Chinese Academy of Sciences Beijing 100049 China

Nepal is located in the central part of the greater Himalayan range with a unique series of mountain chains formed by recent mountain building geological events. As one of the youngest mountains in the world it contributes to diversity of plants and also provided barriers to and corridors through which plants migrated during the ice ages. The higher altitudinal variation with the high mountains, deep river valleys and lowland plains combine with the effects of the summer monsoon and dry winter result with an extraordinary diversity of ecosystems including flora and fauna in a relatively small land area. The existing checklists for Nepal record some 6000 species of flowering plants and about 530 ferns. However, the botanical experts estimate that numbers may go up to 7000 when the poorly known remote regions are fully explored. The information on plant endemism in Nepal Himalaya is not adequately known as Nepal is still struggling to complete long awaited Flora of Nepal project. Endemic species are confined to specific areas and are the first to be affected by land use and other global changes. We sought to explore the spatial distribution of endemic plant species in Nepal in relation to the consequences associated with climatic and geologic changes over time in the region with the help of published literature. It was found that the endemism showed marked spatial variation between open moist habitat and dry inner valleys, the former with higher endemism. The updated records showed 312 flowering plant species to be endemic to Nepal with higher endemism around the elevation of 3800e4200 m at sea level. The recent human population explosion, intensified deforestation, habitat fragmentation and modern day environmental changes are posing greater threats to endemic plant in Nepal. The conservation status and threats to these peculiar species are unknown. Nevertheless, environmental degradation and high poverty rates create a potent mix of threats to biodiversity in this l

关键词： Himalaya Topography Endemism

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Changes in regeneration and leaf traits of Rhododendron campanulatum along a treeline ecotone in central Nepal

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Journal of Mountain Science 2020年第3期17卷 602-613页

作者： SHARMA Prasad Krishna tiwari achyut SHRESTHA Babu Bharat Central Department of Botany Tribhuvan UniversityKathmandu44613Nepal Budhanilkantha School Kathmandu44622Nepal

Changes in population structure and plant functional traits across environmental gradient in the near natural treeline is a critical determinant of environmental changes in treelines. In this study we analyzed population characteristics and leaf traits of Rhododendron campanulatum across treeline ecotone in a trans-Himalayan region of Mustang district in central Nepal. Along 4 vertical transects, a total of 72 quadrats(5 m × 5 m)-34 above Betula utilis treeline and 38 below treeline-were sampled to analyze the population structure, regeneration,specific leaf area(SLA) and leaf-stem relationship of R. campanulatum. Our results showed that the regeneration of R. campanulatum was fairly good in both habitats, as evident from density-diameter *** species showed type Ⅲ survivorship curve in both habitats with the highest mortality during early stage of life. However, the seedling density and mortality was higher below treeline than above treeline. Canopy cover and basal cover were found to be the major factors affecting regeneration, as indicated by higher number of juveniles in relatively open areas above treeline. The total leaf area increased(p <0.001) with stem cross-section area in both habitats. However, the SLA was higher below treeline(55 cm^2/g) than above(47 cm^2/g)(p < 0.001);it also increased with the canopy cover of trees(R^2 =0.59, p <0.001) below the treeline. In conclusion,high density of juvenile, low mortality of seedlings,and low SLA above treeline indicated that the species has successfully adapted in climatically stressful alpine habitat with potential to expand upward.

关键词： Rhododendron Climate change Life table Mortality Specific leaf area Mustang district

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