Browsing by Subject "biodiversity"
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Item BIRD DIVERSITY ALONG AN ELEVATIONAL GRADIENT IN THE MANANG DISTRICT, CENTRAL NEPAL(2015-12) GHIMIRE, ANUJSpecies richness of birds along an elevational gradient in Himalayan region including Nepal is less explored till the present. Studying diversity and community structure of birds will help biodiversity conservation. The present study explores the patterns of diversity and distribution patterns of avian fauna in Manang region, central Nepal and also explores the factors that affect the diversity and distribution. In addition, I also tested if there is any validity of Bergmann's rule for birds in Manang region. To fulfill the above mentioned objectives, data on the distribution of bird communities were collected along an elevational gradient in two valleys in Manang, central Nepal between August and October 2014. In addition to this, I also collected data on a range of environmental variables at all sites in order to determine their association with bird diversity and species composition of bird communities. Point count method in 19 different localities each with an approximate difference of 200 meters above sea level were conducted. At each plot, birds were recorded within a circle of 50 meters radius from a fixed point in a center. Different environmental variables, such as slopes, shrubs, agricultural fields were also documented to see the affect distribution of bird species were recorded at each sampling point. To find out the determinants of bird species richness, generalized linear model (GLM) with Poisson distribution and log link function was used and multivariate analysis (Canonical Correspondence Analysis, CCA) was used to show the relationship between bird species composition and environmental variables. I found that there were 82 species of birds in total of 19 different plots, comprising of 24 families. The largest numbers of birds were represented from Muscicapidae followed by Corvidae, Fringillidae and Phylloscopidae. The highest number of birds were common (n=53) followed by scarce (n=16), frequent (n=10) and rare. Bird species richness significantly decreased with increasing elevations in the overall dataset in Manang district. Species richness of all the birds in Manang increased with the presence of forest and shrubs whereas it decreases with the increase of slope of the land. Surprisingly, there were more species of birds near the settlements in Manang. As species richness, bird composition was influenced by elevation and also other factors such as steepness of the land, presence of agricultural fields or shrubby area. It was found that the body size of the birds increased with increasing elevation (p=0.0007; r2=0.0657), meaning that the Bergmann's rule was true for birds from Manang.Item Study of Biodiversity And Bioactivity Of Entophytic Fungi of Some Himalayan Conifers of Nepal(Department of microbiolgy, 2007) Thapaliya, SrijanaA study was conducted with the aim of studying the biodiversity and bioactivity ofendophytic fungi from selected Himalayan conifers collected from different locationviz. Taxus wallichiana (‘Kavre’, 2,930m), Abies spectabilis (‘Kavre’, 2,930m),Podocarpus nerifolius(‘Kirtipur’, 1,372m) andJuniperus indica(‘Kirtipur’, 1,372m) Altogether 47 endophytes were isolated from the inner bark of the above mentionedHimalayan conifers. Only 29 fungal isolates could be identified. The mostrepresentative fungal isolates identified up to the genus level belonged to the generaPestalotiopsis, Alternaria, Trichoderma, Aspergillus, Paecilomyces, Nigrospora,Helicomyces, Drechslera, Helminthosporium and an endomycorrhiza identified asGlomusspp. The identified endophytic fungal isolates were subjected for screening purpose for theirantifungal activities against the plant pathogenic fungi viz. Fusarium oxysporum,Fusarium moniliforme, Sclerotinia spp., Helminthosporium spp., Alternaria spp.,Geotrichum spp., andGloesporium sporioides by following the dual culture method.The observation revealed that most of the endophytic fungi showed antifungal activitiesagainst plant pathogenic fungi used in this study but Pestalotiopsis spp., Alternariaspp., Trichoderma spp. andHelminthosporium spp. were the ones among showinghighest bioactivity against all the fungal plant pathogens used in the study. Thebioactivity was due to the production of novel bioactive secondary metabolites by theseendophytic fungi. The different isolates of Pestalotiopsisspp., NT-801a, NP-601 and NJ-702 each fromdifferent plant source were chosen as the priority isolates, for fermentation andextraction of novel bioactive secondary metabolites. The dry weight of fungal extractrecorded was 33 mg/500 ml for NT-801a isolate, 17mg/500 ml for NP-601 isolate and32 mg/500 ml for NJ-702 isolate. The presence of the bioactive secondary metabolite in the fungal extract was confirmedby the inhibitory activity against the test fungal plant pathogens. Among the fungalextract, thePestalotiopsis spp. (NJ-702) isolated fromJuniperus indica, showed themaximum inhibitory effect against most of the test fungal plant pathogens, compared tothe other two fungal extracts ofPestalotiopsisspp. isolated from different plant sources. The crude extract was further subjected to TLC analysis. The crude extract was made torun along with authentic taxol and its precursor compound(10-DAB III), as thereference compounds. The R value of the authentic taxol being 0.77 and that of thefungal analyte (NT-801a) being 0.78, (NP-601) being 0.79 and that of (NJ-702) being0.78, suggests the possibility of presence of taxol in all the three fungal extracts.