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Species Richness, Diversity and Density of Understory Vegetation along Disturbance Gradients in the Himalayan Conifer Forest

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Journal of Mountain Science 2014年第5期11卷 1182-1191页

作者： Kesang WANGCHUK András DARABANT prem bahadur rai Maria WURZINGER Werner ZOLLITSCH Georg GRATZER University of Natural Resources and Life Sciences Department of Sustainable Agricultural Systems Division of Livestock SciencesGregor Mendel Strasse 33A Vienna 1180 Austria Renewable Natural Resources Research and Development Center University of Natural Resources and Life Sciences Department of Forest and Soil Sciences Institute of Forestry Ecology Peter Jordan Strasse 82A Vienna 1190 Austria

We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging(gap) and grazing(primarily by cattle) disturbance gradients, and sought to identify drivers of richness, diversity and density of understory vegetation of logged sites. A factorial experiment was conducted in the mixed conifer forest of Gidakom in Western Bhutan. Levels of the logging treatment included small(0.15 – 0.24 ha), medium(0.25 – 0.35 ha) and large(0.36 – 1.31 ha) gaps. The grazing treatment included grazed(primarily by cattle) and ungrazed(where herbivores were excluded by a fence) plots nested within each gap. Data were collected from 12 gaps(4 replicates at each level of logging) using the point intercept method. Shannon Weaver Diversity and Margalef's indices were used to estimate species diversity and describe species richness, respectively. Soil samples were analyzed for pH and nutrients. The interaction effect of logging and grazing was significant(p≤0.001) only on species diversity. Relative to ungrazed areas, species diversity was significantly higher(0.01≤p≤0.05) in medium grazed gaps. Under grazed conditions, soil P was negatively correlated with gap size and species diversity. While species diversity was positivelycorrelated(0.01≤p≤0.05) with soil N in grazed plots species richness was positively correlated(0.001≤p≤0.01) with soil N in ungrazed plots. Relative density of Yushania microphylla and Carex nubigena were higher under ungrazed conditions. Our study suggests that the combined effect of cattle grazing and logging results in higher species diversity of understory vegetation in medium and grazed gaps in mixed conifer forests of Bhutan,whereas increase or decrease in relative density of major species is determined primarily by the independent effects of grazing and logging. From management perspective, forest managers must refrain from creating large gaps to avoid loss of nutrients(mainly P and N), which may eventually aff

关键词： Forest gap Grazing Relative density Soil nutrients Species diversity Species richness

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An Assessment of Yarsagumba(Ophiocordyceps sinensis) Collection in Dhorpatan Hunting Reserve, Nepal

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Journal of Mountain Science 2014年第2期11卷 555-562页

作者： Barna bahadur THAPA Saroj PANTHI Rajesh Kumar rai Uttam Babu SHRESTHA Achyut ARYAL Sabina SHRESTHA Bhushan SHRESTHA Department of National Parks and Wildlife Conservation Babar Mahal Dhorpatan Hunting Reserve Baglung Station Green Governance Nepal Department of Biology University of Massachusetts Institute of Natural and Mathematical Sciences Massey University Graduate School of Biotechnology Institute of Life Sciences and Resources Kyung Hee University Green Energy Mission/Nepal Ghatte Kulo Anam Nagar Mushroom Research Division National Institute of Horticultural and Herbal Science Rural Development Administration

Yarsagumba(Ophiocordyceps sinensis), an endemic species to the Himalayas and Tibetan Plateau, is one of the most valuable medicinal mushrooms in the world. In Nepal, it is distributed largely in isolated patches of alpine grasslands of 3,000-5,000 m elevation. Although it is reported from 27 northernmost districts of Nepal, the local distribution pattern of this species is largely ***, the collection system and local management regime of this species are not well documented. We conducted a field survey at Dhorpatan Hunting Reserve(DHR) among the different stakeholders in January-June 2012 to assess collection sites, patterns and trends and to understand the management regime. We estimated that about 75 kg of Yarsagumba is collected every year from DHR and the amount has been declining since 2008. To manage the resource, locals have initiated regulating the collection by issuing permits, taxing to the collectors, and monitoring the activities of harvesters with the help of park authorities. The revenue generated at local level from the permits has been used for community developmental activities.

关键词： Chinese caterpillar fungus Medicinal fungus Himalayan gold Conservation Yartsagunbu

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Theoretical investigation on mechanical,thermal,and ultrasonic properties of epitaxial nanostructured ZrN layers growth on MgO(001)substrate

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ChemPhysMater 2023年第3期2卷 253-258页

作者： Aadesh Kumar Prajapati Sachin rai Prashant Srivastav Pramod Kumar Yadawa Department of Physics Prof.Rajendra Singh(Rajju Bhaiya)Institute of Physical Sciences for Study and ResearchV.B.S.Purvanchal UniversityJaunpur 222003India

In the present study,we calculated the elastic,mechanical,and thermo-physical properties of Zirconium Nitride(ZrN)/Magnesium Oxide(MgO)(001)nanostructures in the temperature range of 50∼300 K using higher-order elastic *** two fundamental factors,nearest-neighbor distance and hardness parameter,in this tem-perature range,the second-and third-order elastic constants(SOECs and TOECs)are estimated using the Coulomb&Born-Mayer *** computed values of SOECs have been used to calculate Young’s modulus,thermal conductivity,Zener anisotropy,bulk modulus,thermal energy density,shear modulus,and Poisson’s ratio to as-sess the thermal and mechanical properties of the ZrN/MgO(001)nanostructured ***,SOECs are used to calculate the wave velocities for shear as well as longitudinal modes of propagation along crystalline orientations,,andin these temperature *** temperature-dependent Debye average velocity,hardness,melting temperature,and ultrasonic Grüneisen parameters(UGPs)were *** frac-ture/toughness(B/G)ratio in the current investigation was greater than 1.75,indicating that the ZrN/MgO(001)nanostructured layer was ductile in this temperature *** selected materials fully satisfied the Born me-chanical stability *** this ambient temperature,it has been computed how long thermal relaxation takes to complete and how ultrasonic waves are attenuated by thermo-elastic relaxation and phonon-phonon interaction *** results,in combination with other well-known physical properties,can be applied to the non-destructive testing of materials for various industrial applications such as microelectronic devices,optical coatings,batteries,and solar cells.

关键词： Nanostructured layers Elastic properties Thermal conductivity Mechanical properties Ultrasonic properties

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