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Poudel R.C.,CAS Kunming Institute of Botany | Poudel R.C.,University of Chinese Academy of Sciences | Moller M.,CAS Kunming Institute of Botany | Gao L.-M.,CAS Kunming Institute of Botany | And 5 more authors.
PLoS ONE | Year: 2012

Background: Despite the availability of several studies to clarify taxonomic problems on the highly threatened yews of the Hindu Kush-Himalaya (HKH) and adjacent regions, the total number of species and their exact distribution ranges remains controversial. We explored the use of comprehensive sets of morphological, molecular and climatic data to clarify taxonomy and distributions of yews in this region. Methodology/Principal Findings: A total of 743 samples from 46 populations of wild yew and 47 representative herbarium specimens were analyzed. Principle component analyses on 27 morphological characters and 15 bioclimatic variables plus altitude and maximum parsimony analysis on molecular ITS and trnL-F sequences indicated the existence of three distinct species occurring in different ecological (climatic) and altitudinal gradients along the HKH and adjacent regions Taxus contorta from eastern Afghanistan to the eastern end of Central Nepal, T. wallichiana from the western end of Central Nepal to Northwest China, and the first report of the South China low to mid-elevation species T. mairei in Nepal, Bhutan, Northeast India, Myanmar and South Vietnam. Conclusion/Significance: The detailed sampling and combination of different data sets allowed us to identify three clearly delineated species and their precise distribution ranges in the HKH and adjacent regions, which showed no overlap or no distinct hybrid zone. This might be due to differences in the ecological (climatic) requirements of the species. The analyses further provided the selection of diagnostic morphological characters for the identification of yews occurring in the HKH and adjacent regions. Our work demonstrates that extensive sampling combined with the analysis of diverse data sets can reliably address the taxonomy of morphologically challenging plant taxa. © 2012 Poudel et al. Source

Bhattarai K.R.,National Herbarium and Plant Laboratories | Maren I.E.,University of Bergen | Subedi S.C.,Florida International University
Journal of Mountain Science | Year: 2014

Invasive plant species are exerting a serious threat to biological diversity in many regions of the world. To understand plant invasions this study aims to test which of the two plant invasiveness hypotheses; 'low native diversity' vs. 'high native diversity', is supported by the regional distribution patterns of invasive plant species in the Himalayas, Nepal. This study is based on data retrieved from published literatures and herbarium specimens. The relationship between invasive plant species distribution patterns and that of native plant species is elucidated by scatter plots, as well as by generalized linear models. The native plant species and invasive plant species have similar distribution patterns and the maximum number of invasive plant species is found in the same altitudinal range where the highest richness for native tree species is found. There is a clear trend of higher invasive plant richness in regions where native tree species richness is relatively high. Consequently, the native plant richness is highest in the central phytogeographic region, followed by the eastern and the western regions, respectively. The invasive plant species also follows a similar trend. Additionally, the invasive plant species richness was positively correlated with anthropogenic factors such as human population density and the number of visiting tourists. This study supports the hypothesis that 'high native diversity' supports or facilitates invasive plant species. Further, it indicates that native and invasive plant species may require similar natural conditions, but that the invasive plant species seem more dependent and influenced by anthropogenic disturbance factors. © 2014 Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg. Source

Poudel R.C.,CAS Kunming Institute of Botany | Poudel R.C.,University of Chinese Academy of Sciences | Moller M.,CAS Kunming Institute of Botany | Liu J.,CAS Kunming Institute of Botany | And 3 more authors.
Diversity and Distributions | Year: 2014

Aim: To assess patterns of genetic variation and levels of diversity in the endangered allopatrically distributed Taxus contorta, T. mairei and T. wallichiana in highly fragmented and degraded habitats of the Himalayas. Location: Central Himalaya, particularly the area within the political boundary of Nepal and SW Xizang, China. Methods: We used a multidisciplinary approach combining a transect study, population genetic analyses based on chloroplast DNA sequences and nuclear microsatellite data, and ecological modelling to estimate the size-class structure, genetic diversity and differentiation of populations and understand the potential fate of yew populations in the face of rapidly degrading habitats and abrupt climate change. Results: For all three species, the flat regression slopes of the size-class distributions (SCD), and high permutation index values indicate unstable population structure with lower recruitment rates. The chloroplast and nuclear microsatellite data further reveal low genetic diversity, significant population differentiation and high inbreeding for yew species of this region. We identified two strong barriers of genetic discontinuities, where the presence of spatially different ecological environments caused an allopatric distribution of the species. The ecological model projection for the year 2080 forecasted a substantial decrease in size of suitable areas and a range shift towards the north. Main conclusions: The spatial distribution of the genetic variation and diversity within and among the populations of each yew species was largely shaped by their peripheral position in their respective ranges, differences in their evolutionary histories, and the periodic and asynchronous climates experienced by the species, in addition to the severe impacts of anthropogenic activities. Several yew populations in Central Himalaya have already declined to sizes too small to be demographically sustainable. Improved conservation managements, both at the species and landscape levels, should be implemented for the protection of remnant populations. © 2014 John Wiley & Sons Ltd. Source

Taneda H.,University of Tokyo | Taneda H.,National Herbarium and Plant Laboratories | Watanabe-Taneda A.,University of Tokyo | Chhetry R.,University of Tokyo | Ikeda H.,University of Tokyo
Annals of Botany | Year: 2015

Background and Aims The epidermal surface of a flower petal is composed of convex cells covered with a structured cuticle, and the roughness of the surface is related to the wettability of the petal. If the surface remains wet for an excessive amount of time the attractiveness of the petal to floral visitors may be impaired, and adhesion of pathogens may be promoted. However, it remains unclear how the epidermal cells and structured cuticle contribute to surface wettability of a petal. Methods By considering the additive effects of the epidermal cells and structured cuticle on petal wettability, a thermodynamic model was developed to predict the wetting mode and contact angle of a water droplet at a minimum free energy. Quantitative relationships between petal wettability and the geometries of the epidermal cells and the structured cuticle were then estimated. Measurements of contact angles and anatomical traits of petals were made on seven herbaceous species commonly found in alpine habitats in eastern Nepal, and the measured wettability values were compared with those predicted by the model using the measured geometries of the epidermal cells and structured cuticles. Key Results The model indicated that surface wettability depends on the height and interval between cuticular steps, and on a height-to-width ratio for epidermal cells if a thick hydrophobic cuticle layer covers the surface. For a petal epidermis consisting of lenticular cells, a repellent surface results when the cuticular step height is greater than 0·85μm and the height-to-width ratio of the epidermal cells is greater than 0·3. For an epidermis consisting of papillate cells, a height-to-width ratio of greater than 1·1 produces a repellent surface. In contrast, if the surface is covered with a thin cuticle layer, the petal is highly wettable (hydrophilic) irrespective of the roughness of the surface. These predictions were supported by the measurements of petal wettability made on flowers of alpine species. Conclusions The results indicate that surface roughness caused by epidermal cells and a structured cuticle produces a wide range of petal wettability, and that this can be successfully modelled using a thermodynamic approach. © 2015 The Author. Source

Maren I.E.,University of Bergen | Bhattarai K.R.,National Herbarium and Plant Laboratories | Chaudhary R.P.,Tribhuvan University
Environmental Conservation | Year: 2014

In developing countries, the landscape surrounding agricultural land is important for maintaining biodiversity and providing ecosystem services. Forests provide a full suite of goods and services to subsistence farmers in the Himalayan agro-ecological system. The effects of biomass outtake on woody species richness and composition were analysed in forests under communal and government management. Interviews on forest use and perception of forest condition and ecosystem service delivery were conducted in farmer households bordering the forests. Significantly more woody species were found in the community managed forests. Species richness was negatively correlated with walking distance from the nearest village and increasing levels of anthropogenic disturbance. Community forests were generally less degraded than government managed forests, giving support to common pool resource management. Woody vegetation represented a crucial source of fuelwood, timber, fodder, and edible, aromatic and medicinal plants. Using a multidisciplinary framework to analyse ecosystem integrity and ecosystem service delivery enabled a finer understanding of these complex agro-ecological systems, giving support to evidence-based management and conservation planning for the future. Copyright © 2013 Foundation for Environmental Conservation. Source

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