Variation of plant species richness at different spatial scales

It is now realized that the variation in species richness is influenced by spatial and temporal scales. Pattern and scale are a central focus in ecology and biogeography. The species richness relationship depends on the scale of study and their correlated factors. The broad objective of this review is to elucidate how different scales are correlated with different explanatory variables to generate patterns of species richness. Addressing the problem of scale has both fundamental and applied importance in understanding variation in species richness along gradients. The understanding of pattern, its causes, and consequences is central to our understanding of processes such as succession, community development, and the spread and persistence of species. According to the hierarchical theory of species diversity there are mainly three categories of scales: local, landscape and regional. The local species richness or α-diversity is the diversity of individual stands. The β-diversity or species change is turnover between two elevational bands or between two plots or two sites. The regional or γ-diversity is the total richness of whole mountains or study systems and it has a combined influence from α- and β-diversity. The local species richness is affected by both local-scale processes (e.g., internal interactions) and broad-scale processes (e.g., evolutionary). Different explanatory variables according to the scales of study are necessary to explain variation at different spatial scales. Local factors (e.g., disturbance, grazing and tree cover) have been used to detect variation at a local scale. Generally, topographical factors are used to detect variation in species richness at a landscape scale; whereas climate, water-energy dynamics and historical processes are used to detect variation at a regional scale. However, it is not easy to separate strictly one scale from other because there is no clear boundary between them. The study of the whole elevation gradient from tropical to alpine zone or long latitude is a broad-scale study. The intermediate scale is a study on a local mountain, which covers the subtropical to warm temperate zones. To explain patterns of species richness, a pluralistic body of hypotheses, which incorporates historical, biological and climatic factors, is needed. This is depicted by the strong relationship between climate, biological interactions, and historical processes in influencing variation in species richness at different spatial scales.Botanica Orientalis – Journal of Plant Science (2017) 11: 49–62

Floodplain succession pattern along Budhi-Rapti River bank, Chitwan, Nepal

Riverine floodplain is one of the most productive lowland ecosystems in Nepal. However, floodplain ecology is less understood due to its fluctuation. Budhi-Rapti River in Chitwan, central Nepal formed a floodplain along the Khorsor zone of Barandabhar corridor. This study was carried out to understand the floodplain ecosystem development after plant succession. The space for time substitution method of vegetation sampling was adopted in order to sample the floodplain created at different chronosequence. The floodplain that lies perpendicular to and 200 m away from the Budhi-Rapti river was sampled. Systematic sampling was done along two parallel transects, almost 200 m apart from each other. Sampling along the transect started right after 200 m away from the Budhi-River bank. Initial position of these transects towards Budhi-Rapti river was believed to be the youngest floodplain, which slowly getting older after passing away from the river. Abundance of vascular plant species was recorded in sample plots of 20 × 20 m each subdivided equally into 4 subplots (each of 100 m2). Along each transect, vegetation data was recorded from a series of 20 plots, placed 50 m apart from each other. Successional scores were calculated and utilized as environmental variables after applying non-metric multi-dimensional scaling (NMDS) through metaMDS. Total and life form (herbs, shrubs and trees) richness patterns were calculated. Altogether, 158 species of vascular plants under 60 families and 136 genera were recorded. Gramineae was the richest family followed by Leguminosae, Asteraceae and Cyperaceae. Total species richness showed significant negative correlation with the NMDS1 and NMDS2, which justified a convergent pattern of succession. Herb, orchid and shrub species richness also showed significant declining pattern with NMDS1. Persicaria barbata, Parthenium hysterophorus, Ageratum conyzoides and Typha angustifolia were early succession indicator species; whereas Albizia lucidior, Miliusa velutina, Ficus hispida, Bauhinia purpurea and Brassaiopsis glomerulata were the late succession tree species. This study agreed with the convergent model of succession.Botanica Orientalis – Journal of Plant Science (2017) 11: 12–26

Fuelwood resources and their use pattern by Bhotia community in Niti valley, Western Himalaya

The local communities of the Himalaya have been using fuel wood as one of the major sources of energy since millennia. Their dependency on these resources as primary source of fuel wood has resulted in unsustainable pressures on the forests. The present communication aims to access the fuel wood resource and consumption pattern of Bhotia, an ethnic community in a cold arid and buffer zone of Nanda Devi Biosphere Reserve, i.e. Niti valley in the Western Himalaya. Within the Niti valley, 87 households in six villages were surveyed using open and close-ended structured questionnaire. Use Index (I%) of each fuel wood species was calculated to evaluate the key species used by the inhabitants and their preferences. The study revealed use of 10 species for fuel wood (five species each of tree and shrub) by the Bhotias. Pinus wallichiana (I = 96.6%) followed by Cedrus deodara (93.1%) were the preferred tree species for fuel wood, while among shrubs, Juniperus indica and J. communis were extensively used. Fuel wood consumption in the Niti valley was much lower (1.6±0.2 kg household-1 day-1) than other villages in the Greater Himalaya (4.9±0.4 kg household-1 day-1). The seasonally employed which formed 23% of the surveyed households, collected almost twice as much fuel wood than the employed households (9.2±0.4 and 5.2±0.4 quintals season-1, respectively). As the area is characterized by sparse vegetation cover, low primary productivity and short growing season, and is thus highly susceptible to irreversible changes of natural habitats. The study suggests that providing alternate and non-conventional energy sources such as solar cookers and fuel efficient portable ovens to the inhabitants at subsidized rates could reduce the pressure on nearby forests. Botanica Orientalis – Journal of Plant Science (2017) 11: 1–6

Herbivory damage in native Alnus nepalensis and invasive Ageratina adenophora

There are numbers of invasive and naturalized alien species in Nepal but studies related to herbivory effects on such species are scarce. An issue of debate is whether invasive alien species get benefited by less herbivory damage in their introduced range. In this study, we investigated the level of herbivory damage in Alnus nepalensis in an area invaded by Ageratina adenophora in Nepal. The damage was compared between invasive A. adenophora and native Alnus nepalensis. Results showed that A. adenophora experienced lower level of leaf damage by herbivores than that of A. nepalensis. This indicated that the invasive A. adenophora might have benefited from reduced herbivory damage behind its successful invasion in Nepalese forest. Further studies are needed to confirm whether controlling of herbivores to lessen the damage in native Alnus nepalensis could enhance its competitive ability against Ageratina adenophora in native vegetation of Nepal.Botanica Orientalis – Journal of Plant Science (2017) 11: 7–11

Cytotoxic activity of crude extracts of Dendrobium amoenum and detection of bioactive compounds by GC-MS

Dendrobium amoenum is an epiphytic orchid used as tonic because it has many derivatives of phenols. The crude extract of this orchid has been shown to have antioxidant activity. The objectives of this research are to explore the cytotoxic activity of antioxidant-rich crude extract against the human cervical carcinoma and glioblastoma cell lines by MTT assay and to detect the compounds by GC-MS. Methanol (DAM) extract of D. amoenum showed high cell growth inhibition percentage against the tested cell lines. DAM extract showed high cytotoxic activity against HeLa cells (IC50 – 110.22 μg/ml) and least activity against U-251 cells (IC50 – 550.55 μg/ml). Thirteen compounds were detected and identified in the extract. Based on abundance, four major compounds detected were: (E)-13-docosenoic acid; oleic acid; 11-octadecenoic acid, methyl ester; and hexadecanoic acid, 2,3-dihydroxypropyl ester. The cytotoxic activity of DAM extract is probably due to the presence of these bioactive compounds, confirmation of which needs further investigation. The result also highlighted the potential of this orchid as the source of natural anticancer drug and to explore their isolation, identification and characterization.Botanica Orientalis – Journal of Plant Science (2017) 11: 38–42

Comparative study of macrofungi in different patches of Boshan Community Forest in Kathmandu, Central Nepal

Macrofungi are considered as a group of high-value forest resources worldwide. In this paper, we report species richness and composition of macrofungi in three different forest patches (Schima-Castanopsis, Pinus and Alnus forest) of mid-hill, central Nepal, which were managed under Boshan Community Forest. A Systematic random sampling was applied where 20 rectangular plots of size 10 m x 10 m were laid at 1500 m to 1600 m elevation in each forest type. Species richness and composition of macrofungi were accessed in each forest type. Schima-Castanopsis forest was the richest in terms of macrofungal diversity (70 species), followed by Alnus forest (64) and Pinus forest (56). Polyporaceae was the largest family, followed by Amanitaceae. Agaricales (Rusulla and Amanita) were dominant in Schima-wallichi and Alnus forests, whereas Boletales were dominant in Pine forest. Macrofungal species richness increased with increasing canopy, soil moisture and soil pH. The species richness, however, had weak relationships with litter cover and disturbance. Based on the present study it can be concluded that the study area is rich in macrofungal diversity. Moist soil followed by litter and decaying wood assist the higher diversity of macrofungi. Species diversity is higher in moist and dense canopy forests (like, Schima-Castanopsis and alder) than in open and dry pine forest. Soil moisture, soil pH and tree canopy cover are the most important variables affecting macrofungal diversity. Botanica Orientalis – Journal of Plant Science (2017) 11: 43–48

Trade and conservation of medicinal and aromatic plants in western Nepal

This paper quantifies the volume and value of medicinal and aromatic plants (MAPs) traded from Baitadi district in western Nepal. Information related to trade, in the Fiscal Year 2014/015, was collected through pre-tested structured questionnaire. Harvesters (n = 24) and the entire population of sub-local (n = 35) and local (n = 7) traders were interviewed to quantify the value and volume of MAP trade from the district. Results showed that 15.2% households were engaged in harvesting of MAPs for trade, contributing 9.5% of the total cash income giving an impression that MAPs provide supplementary source of income. A total of 731.5 tons of MAPs, comprising 17 products (from 17 species) with total value of NRs 31.3 million (US$ 315,175) was traded from the district. Rittha (Sapindus mukorossi), tejpat (Cinnamomum tamala) and pakhanved (Bergenia ciliata) were traded in higher amounts, representing 356.5, 171.0 and 70.0 tons, respectively. The cumulative value of trade was highest for satuwa (Paris polyphylla) with NRs 7.7 million. Nepalgunj is the favoured ‘transit’ city for the export of MAPs to India accounting for more than 82% of MAPs sourced from Baitadi. Satuwa has been identified as the most vulnerable species mainly due to premature and over-harvesting in response to high price and growing regional demand coupled with slow growth and high habitat specificity that may results in impaired population growth, thus demanding a detailed bio-physical studies. The study finds that strict regulatory mechanism like ban proves to be less effective in species conservation and suggest adopting alternative management strategies.Botanica Orientalis – Journal of Plant Science (2017) 11: 27–37

Volatile organic metabolites and their importance in Senecio L. (Senecioneae: Asteraceae)

The present work aims to characterize volatile secondary metabolites in Senecio L. for delimiting taxa at the infrageneric level. Analysis of n-hexane fraction of ethanolic extracts of five species of Senecio L. (S. laetus Edgew., S. nudicaulis Buch.-Ham. ex D. Don, S. raphanifolius Wall. ex DC., S. royleanus DC. and S. scandens Buch.-Ham. ex D. Don) from Nepal Himalaya revealed the presence of a number of volatile secondary metabolites. Among them, 17 metabolites, viz., acorenol, bergamotene, cadin, cadinene, calarene, caryophyllene, cumialdehyde, cycloprop(e)azulene, elemol, farnesene, hexanol, intermedeol, muurolene, naphthalene, naphthalenone, propenoic acid and tridecane were considered for their potential use in chemotaxonomy of the genus. All species were characterized by the presence of cadin, elemol, farnesene, muurolene, naphthalenone and propenoic acid and absence of acorenol, cycloprop(e)azulene, hexanol and intermedeol. Cumialdehyde is present in all species except S. royleanus; cadinene is present in all tested species except S. nudicaulis and S. royleanus. Moreover, S. nudicaulis can be delimited from other species by the presence of bergamotene; S. royleanus can be delimited from other species by the presence of tridecane and caralene. Caryophyllene is present in S. raphanifolius and S. scandens and absent in S. laetus. Naphthalene is present in S. nudicaulis, S. royleanus and S. scandens, and absent in S. laetus and S. raphanifolius. Presence and absence of a single metabolite or a group of volatile organic metabolites indicates its significance as the taxonomic marker for delimiting taxa at infrageneric level. An artificial dichotomous key is prepared to delimit the taxa.Botanica Orientalis – Journal of Plant Science (2016) 10: 12–18

Medicinal plants used against gastrointestinal disorders by the Tamang people in Rasuwa district, central Nepal

The different ethnic groups dwelling in different phytogeographic belts of Nepal have their own traditional system of knowledge on application of plant resources for health care. The traditional knowledge of using plants is passed on from generation to generation as folklore. Rasuwa district is rich in variety of flora especially medicinal plants and ethnic people (mainly Tamang) are familiar with medicinal resources and possess rich ethno-pharmacological knowledge. These resources provide huge opportunities for community development and livelihood improvement. This paper will present the documentation of medicinal plant used for gastrointestinal disorders in Chilime, Gatlang and Thuman Village Development Committees in Rasuwa district, north-central Nepal.Botanica Orientalis – Journal of Plant Science (2016) 10: 19–23

Export of medicinal and aromatic plant materials from Nepal

Medicinal and aromatic plants (MAPs) have been identified as one of the potential high value commodities in Nepal with huge prospects for economic development. However, data about MAP consumption, volumes of trade and levels of demand are inadequate. In Nepal, there is a general lack of reliable trade data that constrains the estimation of total amount of MAPs in trade. This study aims to assess current trends in volume and value of MAP commodities exported from Nepal and identify the major destination countries. We mainly used formal trade data of Nepalese MAP products over the last 10 years (2005 to 2014) from the repository of UN COMTRADE database accessed via TRADE MAP. Results indicated that the export value of MAP products increased from USD 27.49 million in 2005 to USD 60.09 million in 2014 (mean for the last 10 years being USD 39.34 million) and this increment is primarily due to increase in price, as the trade volume follows decreasing trend over the same periods. The average annual export amount of Nepalese MAP products for the last 10 years has been calculated to be 13.23 thousand tons (range 10.77–20.25 thousand tons). The rise in export value of MAP products indicates increasing demand of MAPs globally. Nepalese MAP commodities were exported to almost 50 destinations. In terms of volume, India has been the major importer of MAP materials all these years. However, China stood top among the countries sharing high value to Nepalese MAP trade. The trade statistics show that, for the total trade value considering the MAP materials at broad category, the export of products (e.g., spices and flavors) other than listed in HS code 1211 should also be considered for appropriate valuation. Despite the decrease in trade amount, spices and flavors have fetched a gradually increasing price per unit volume which is apparent by the fact that these herbs have ever increasing market demand. Nepal can reap maximum benefit from growing international demand of MAPs given that Government impose strict check in borders to minimize the underestimation, train concerned authorities in proper identification of MAPs products and help to develop species-specific 8- and 10-digit HS Codes for proper documentation of imports and exports of MAPs products.Botanica Orientalis – Journal of Plant Science (2016) 10: 24–32