Browsing by Subject "Species composition"
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Item Ecological modelling of vascular plant diversity under different climate and land use change scenarios in Nepal Himalaya(Department of Botany, 2021) Rai, Sanjeev KumarThe effect of climate, topography and land-use on the plant species richness and composition are widely studied topics in ecology. Recent scenarios of climate change studies also show the effect on the species diversity and gain in new area and loss in old habitats. The species richness is considerably high in Nepal with respect to its surface area due to its topography and diversity in micro climates. Climate change and land use change are affecting such richness and composition world widely. Current study was focused on assessing the species richness of vascular plants, their composition and finding the environmental variables which affect them in different elevations and land use gradients in the Nepal Himalaya. We also assessed the effect of climate change on the future distribution of Betula utilis and Larix potaninii var. himalaica which are both tree-line vascular plant species in Nepal Himalaya. The elevation of study sites ranged from 2200 m to 3800 m in six river valleys of Gorkha, Solukhumbu and Taplejung districts of Nepal. Four land use types namely crop field, meadow, exploited forest and natural forest were surveyed. Species were recorded in 25m x 2.5m plots in each land use type. We measured soil temperature as well as air humidity and temperature with data loggers on all study sites. The recorded data show a clear gradient of elevation and land use types designed in current study. Two visits were done for all plots in two different seasons. Although there are some common species recorded in both visits, the species record in individual visits are also unique. The field survey revealed a total of 840 vascular plant species belonging to 492 genera of 120 families. Among them 631 were dicots, 159 monocots, 12 gymnosperms and 38 pteridophytes. There were 96 tree species, 110 shrub species, 586 herbs and 48 climber species. Asteraceae comprised the highest number of species (85 spp.). Multivariate ordination techniques such as Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to analyze the patterns of species composition and Generalized Linear Model (GLM) was used to find out the significant environmental variables affecting the species richness. In DCA, the first two axes were more than 4.0 standard units inferring high beta diversity. Three sets of environmental variables namely microclimate, bioclimate and topography were used for the ordination. In CCA, isothermality, minimum temperature of the coldest month, precipitation seasonality, precipitation of the coldest quarter were significant contributing bioclimatic variables. Similarly, exposition, land use types, elevation, aspect, slope, region, and valley were vi significant constraining variables for the species composition. Same set of predictor variables were used to develop three models using GLM. In addition, a synthetic model was developed by combining significant predictor variables from each set of the variables. Linear combination of mean soil temperature, mean humidity, minimum humidity, maximum temperature of warmest month, precipitation of the driest month, precipitation seasonality, valleys, land use types, elevation and latitude produce the best model in forward selection procedure. Maxent modelling was done to predict the future distribution of vascular plants under different climate change scenarios by 2050 and 2070. We chose two species namely Betula utilis and Larix potaninii var. himalaica for this purpose. Both plants occur on high Himalaya up to tree-line. Larix is a deciduous conifer which has limited distribution in central Nepal and adjoining region of Tibet, China. Betula utilis is a deciduous broad-leaved plant with wide distribution from Pakistan to China. It occurs in almost all high mountains of Nepal. The bioclimatic variables were taken from CCSM4 climate database with RCPs 2.6, 4.5, 6.0, 8.5 for 2050 and 2070. Additionally, elevation, aspect and land use types were taken as predictor variables which were taken from the land cover map of Nepal 2010. All models were validated with various statistical tests. All models showed AUC > 0.9, accuracy between 88.4875 and 95.2858, error rate between 0.1151 and 0.0471, and TSS between 0.6359 and 0.7613. The validation parameters showed the robustness of the models. The elevation and annual mean precipitation were main contributing factors for the distribution of Betula utilis and Larix potaninii var. himalaica respectively. The distribution area of Betula utilis will decrease by -18.72% under RCP 2.6 but will increase in all other scenarios by 2050 and 2070. The new gains in area will be distributed towards the western mountains at all RCPs in 2050 and 2070. The predicted area of Larix potaninii var. himalaica did not show specific trend of increment or decrease at all RCPs by 2050 and 2070. The findings of the current study will be applicable in the assessment of effect of environmental and land use variables on the species composition and richness other group of plants too. Current study will be also helpful in devising future policies of conservation of rare, vulnerable, and threatened plant species whose distributions are more likely to be affected by the climate change in the future. Key words: Biodiversity, SDM, Species composition, Species distribution, TreelineItem Floral Species Richness Pattern in Arghakhanchi and Adjoining Areas, Nepal(Institute of Science & Technology, 2023-12) Nepali, BaburamThe biodiversity and their pattern may vary from a broad geographic area to a small local scale due to changes in their linked components along spatial and temporal gradients. Basic knowledge of distribution, diversity, and roles is necessary for the conservation of any group of organisms. In this synthesis I examined the variations in species composition and richness patterns over various spatial gradients and how they relate to the nutrients found in the low mountainous regions of west Nepal. This thesis is based on field-survey data of vascular and lichen species, analyzed soil data as well as secondary data from published articles. The study is mainly focused on vascular plant as well as lichen species composition, richness and soil heterogeneity, which is based on direct field sampling in national and community forest of Arghakhanchi and adjoining area: Resunga forest of Gulmi district, Nepal, to compile baseline information. The survey was done in autumn and spring seasons for two consecutive years (2018-2019) at various elevations that varied from 200 to 2300 m. The primary data of vascular plants was collected by use of 10 X 10 m quadrats in stratified random sampling design along the elevational gradient. From the same sampled plots, lichen specimens and soil samples were also collected. The soil samples were chemically analyzed in laboratory. The vascular and lichen specimens were identified by comparing with already identified herbarium specimens and by following identification keys. The data was analyzed by use of various statistical techniques: Generalized linear model (GLM) regression, PerManova, DCA and CCA ordinations in R software. The elevational diversity indices (Shannon-Wiener, Simpson and Pielou’s evenness) of plant life forms were estimated. A total of 606 species of vascular plants and 47 species of lichens were found in the field. Plant life forms classified by Raunkiaer (1934) yielded the following results: 265, 37, 158, 57, and 89 species for Phanerophytes, Chamaephytes, Hemicryptophytes, Geophytes, and Therophytes, respectively. According to the different types of forests, the mixed pine forest containing Schima wallichii, Castanopsis indica, Pinus roxburghii obtained the highest vascular species richness. Capillipedium assimile is the species which obtained bear the highest Important Value Index in all three ecological regions (Tropical, Sub-tropical and Temperate). The regression results show that all vascular plants, life-forms species and lichen species follow the statistically significant elevation-dependent unimodal structure. Unimodal pattern is found as common elevational species richness pattern, but is not compulsory pattern against elevation in small areas. The explanatory factors show a stronger influence on species composition than species richness, according to correlations and canonical correlations. The Hemicryptophytes, Phanerophytes and Therophytes had significant positive relationships with elevation and soil nitrogen, whereas the Chamaephytes, and Geophytes, had a negative relationship. Elevation and nitrogen function show the uniqueness of the interplay between life forms by acting as key factors of plant dispersal. Other factors-RRI, soil pH, phosphorus, potassium show comparatively less impact in species composition. According to the appearance of a peak in species diversity at nearly the same elevation and a pattern that is similar, the diversity of vascular plants promotes the abundance of lichens. The diversity of lichens was strongly correlated with the habitat and elevation than the aspect of hills. At all levels of spatio-temporal gradients, species richness and composition patterns are strongly scale dependent. Certain variables, such as soil-related local-scale heterogeneity and slope aspect, are essential for figuring out species composition and richness trends. Based on our results, it is cleared that the study area: Arghakhanchi district and its adjoining areas provide variable habitats for vascular as well as lichen community. Open ground floor is mainly rich in native as well as alien herb plant species, which are less dominant in forests. It is clear that species composition is a more useful tool in landscape ecology and biogeography research than species richness. Therefore, plant community structure should be used as a reliable and insightful indicator in biogeography studies and conservation planning.Item Seasonal diversity and habitat utilization of bird in The Barandabhar Corridor Forest Of Chitwan District, Nepal(Department of Zoology, 2009) Ghimire, Bipin ChandraI carried out survey was during October 2007 to May 2008 in the Barandabhar Corridor Forest (BCF) covering an area of 12300 hectares to determine the seasonal diversity and habitat utilization of bird .The BCF is one of the Important Bird Areas (IBAs) of Nepal. My objectives were to explore the current species composition extant birds, to investigate diversity pattern of birds and to examine the pattern of habitats utilized by birds. I adopted line transects method using six permanent line transects which ran through eight major habitat including Sal forest, Open grassland, Salforest and grassland, Grassland associated with few sal trees, Wetland, Mix riverine, Mixforest and Sal mixed forest. I recorded 123 bird species represented by 15 orders and 43 families in two seasons autumn and spring. Species diversity and relative diversity of the birds were calculated by using Shannon-wiener function and Jacob’s coefficient. Among the species recorded, 94 species (76%) were resident,16 species (13%) were summer visitor,12 species (10%) were winter visitor and 1 species (1%) was local migrant. Diversity index of birds showed highest value in (1.70) spring followed by autumn (1.54). Similarly Jacob’s coefficient for relative diversity in autumn and spring is 0.825 and 0.806 respectively. Analysis of Variation (ANOVA) showed that there was significant relation between the number of bird population with variation of season (p<0.05, df= 1 and 7) and habitat types (p<0.05,df=7 and 7). Bird populatio0n were found highest in the Sal forest (46.48%), followed by Open grassland (22.81%), Sal and grassland (12.21%), Sal mixed forest (8.70%),Wetland(2.88%),Mix riverine (2.47%), Grassland associated with few Sal trees (2.02%) and Mixed forest (1.3%). I also recorded different activities of birds most of which were observed were found in the resting, eating, calling and flying. The activities of the birds like feeding and nesting were only observed in the spring season. Globally threatened bird Lesser Adjutant Leptoptilus javanicus was also recorded during my survey. I recorded six species of birds, which were listed in the Appendix II as described by Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Human disturbances were the main factors, which had jeopardized the survival of avian fauna in the BCItem Tree Species Richness,Carbon Stock and Regeneration Status of Maltol Community Forest and Dhanushdham Protected Forest in Dhanusha, Nepal(Department of Botany, 2020) Sunar, SajinaTree species are the dominant component of forest ecosystems which influence most structural and functional attributes of these ecosystems. This study aims to assess and compare tree diversity and carbon stocks in two different management regimes namely Maltol Community forest (MCF) and Dhanushadham Protected forest (DPF). The studied MCF and DPF lied in tropical region at an altitude 80 to 230 masl in Dhanusha District of Nepal. Altogether 120 plot of 25 × 25 m2 each was established by following the stratified random sampling technique for assessing tree diversity and carbon stock in both forests. Species enrooted and encountered inside the plot were recorded. All tree species (≥6cm DBH) were tagged and their both DBH and height were measured. The allometric equation biomass-diameter regression (Model II) developed by Chave et al., (2005) was used for estimation of carbon stock of tree species and tree species diversity by Simpsons and Shannon-Wiener indices. Descriptive statistics with Pearson correlation and one way ANOVA from SPSS- Software and Microsoft Excel were used to perform the statistical analysis. The carbon stock value was found to be 1.2305t/ha in MCF and 5.592t/ha in DPF. Community forest found to have lower value of tree carbon stock than the carbon stock of protected forest. But in case of tree diversity it was recorded high in MCF (34) than in DPF (29). Shorea robusta was found to be the single dominant species in both DPF and MCF with higher basal area (26.802m²/ha and 6.65m²/ha) and contributed 87.93% and 61.99% of the carbon stock respectively. The contribution of carbon stock of two co-dominant tree species in MCF are 8.98% of Terminalia chebula and 5.18% Lannea coromandelica. Lower value of basal area in both forest types in the present study suggests that both the forests are in an immature developmental phase. The size class distribution diagram of all trees showed reverse J shaped pattern indicating a good regenerating capability of the forest. But the regeneration of Shorea robusta of both forests in the present study followed the trend as trees density/ha > saplings density/ha > seedlins density/ha indicated the poor regeneration of Shorea robusta. There was significant (P<0.05) difference between the carbon stock in both forest types.