Browsing by Subject "Elevation gradient"
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Item Diversity and Distribution of Invasive Alien Plant Species Along Road Network in Central Nepal(Department of Botany, 2015) Paudel, NirmalaInvasive alien plant species are spreading rapidly in Nepal and can have irreversible environmental and economic problem if not managed in time. For the proper management of IAPS detail information regarding their diversity and distribution is needed. In this study a detail survey of IAPS distribution was carried out during June- July in 2013 along road networks in Central Nepal. The study also dealt with the variation in species richness pattern across land use types and along elevation gradient. IAPS distribution was assessed through systematic location of sample plots at an interval of 10km in plain areas and 5km in hilly areas. At every specified distance, a 10 × 10 m x 2 plot was defined along the sides of the road. At each plot, IAPS encountered within the plot, their phenophases, presence of biocontrol agents and three most dominant IAPS in terms of cover were recorded. The cover was estimated visually and the frequency of individual IAPS was calculated. The geographical distribution map of each IAPS and overall species richness distribution pattern map was prepared using Arc GIS. A total of 340 plots were sampled covering 2075km of road network. Among the 18 species of invasive alien plants recorded from roadside vegetation, Bidens pilosa had the highest frequency whereas Eichhornia crassipes had the lowest. And Ageratina adenophora was the first dominant species in 30% of the sample plots. IAPS richness showed unimodal pattern of distribution along the elevation gradient. There was significant difference in species richness across land use types. Grazing and fallow land was more vulnerable to invasion, as reflected by the highest species richness in comparison to other land use types (Agricultural land>Shrubland>Forest>Wetland). A negative linear relationship was obtained between frequency (%) and year of record of the IAPS. There was no significant relationship between elevational limit and minimum residence time of IAPS. Most of the IAPS were concentrated to the tropical and sub-tropical region. Middle mountains had greater IAPS richness in comparison to other physiographic regions.This study concludes that IAPS have been spreading rapidly along road networks in Central Nepal. The road networks are acting as dispersal corridors and source areas for plant invasion. Therefore, comprehensive study of IAPS distribution and their impacts has to be carried out at national level which may be useful to develop management strategies for controlling biological invasion. Keywords: Biological invasion, Invasive alien plant species, Species richness, Elevation gradient, Disturbance, Road network, Frequency, Residence time, Distribution maps.Item Floristic composition of Bryophytes and its diversity along the elevation gradient of Palpa District, Nepal(Department of Botany, 2023) Neupane, TulsiBryophytes are very important groups of land plant with a varied ecological and economic importance. These are second most diverse group after angiosperm, though least concerned group in the field of research and documentation. Various studies have suggested making an initiation to promote research on various unexplored region of Nepal so as to complete the documentation process of bryoflora. The aim of this study is to record the floristic information of the bryophytes, its species richness in relation to various environmental variables including the soil macronutrient along the tropical and sub-tropical band Palpa district where no studies are taken place till date. Systematic random sampling methods was used where the circular plots of 10 m radius was laid with 5 (1 m x 1 m) subplots each. Similar 5 sample plots were laid 50 m in each elevation band. The elevation band of the study area was from 300 m- 1500 m where the plots were laid at an interval 300± 85 m depending upon the topography. In each plot various environmental variables were recorded such as elevation, canopy cover, bareground, rock cover, other plants, herb cover, bryophytes cover, organic carbon, nitrogen content, phosphorous, potassium. In total 39 species were collected from the study area with dominancy of mosses. The regression analysis showed statistically significant linear inclining relation with elevation gradient. Declining linear relation was found for canopy cover and total species richness and also for both liverworts and mosses but the variable was insignificant for the hornworts. Declining linear relation was also shown for bare ground and the relation with other plants species, rock cover, herb cover, herb cover and various soil parameter (Organic matter, Nitrogen, Potassium, Phosphorous) was insignificant but mosses showed significant declining relationship with Potassium content though various studies showed significant relations with the soil macro-nutrients. We expected that the study will give more species as compared to previous study done in the western region in the same elevation which was not true. So, there might be soil and rock parameters which may be the reason of low richness of the species. So, further research with soil micro- nutrients and rock parameter may suggest the clear reason of the low number of species.Item Seed germination responses of a mountain medicinal herb Aconitum spicatum to different environmental conditions(Department of Botany, 2023) Gaire, Bishnu SharmaGermination studies of medicinally important mountain plants under different environmental conditions is potentially important to understand the impacts of climate and other environmental changes. Seeds from different populations of a species along the elevation gradient may respond in different directions and intensity to the changing environmental conditions. In this study, seed germination patterns of a mountain medicinal herb Aconitum spicatum were analyzed to understand variation under environmental gradients. Seeds of Aconitum spicatum collected from three different elevations (sub alpine to alpine) were germinated in growth chamber under different temperatures (low: 25/15°C; high: 30/20°C), light environment (12h photoperiod and complete dark, white and far-red light) and water potentials (−0.1, −0.25, −0.5, −0.75, −1MPa). Freshly collected as well as the seeds stored for one year were used in the germination experiments. Seed mass, Germination percentage (GP), Mean germination time (MGT) and Timson’s index (TI) were calculated. The result showed that seeds from low elevation comparatively had higher seed mass and germination than high and mid elevation. At low temperature, seeds had higher GP and TI than in high temperature while MGT was longer in high temperature. With increasing level of water stress, germination decreased. Germination was highest in white fluorescent light than far-red light. Seed germination percentage and the Timson’s index increased after long duration of cold storage (73 weeks). The results of this study advance our knowledge and comprehension of the potential effects of climate change on alpine plants. This study found that there wasn't always a consistent pattern associated to elevation and that germination responses varied greatly among elevational provenances. Another important conclusion of the current study is that it may not be enough to characterize a species' germination response by examining only one population since, as it showed, local environmental conditions may have an effect on seeds.Item Variation in Adaptive Traits of an Endemic Meconopsis Napaulensis DC. along an Elevation Gradient in Alpine Himalaya,Central Nepal(Department of Botany, 2015-09) Rana, NarmadaUnderstanding the pattern of variation in adaptive traits of rare and endemic species along environmental gradient can suggest important implications for developing optimal strategies for species conservation and sustainable management. In this study we aimed to study variation in life-history traits of an endemic species M.napaulensis DC. along an elevation gradient in Langtang National Park,Central Nepal covering three populations. Each population was investigated two times (2013 and 2014)covering different seasons. Population sampling was made to read habitat during peak growing period (during monsoon)except seed output, which was studied during late growing period (post monsoon).Entire area of each population was extensively surveyed to record all the individuals,including plants in flowering or fruiting and their detail vegetative characteristics and traits related to population fitness. Analysis of the habitat features showed that M. napaulensis exhibited high habitat specificity.M. napaulensis was restricted to open and rocky habitats of high altitudes.M. napaulensis growing sites had low vegetation cover indicating decreased inter-specific competition.M.napaulensis showed high variation in traits due to altitudinal variation, climatic condition and disturbances. Specifically reproductive traits discriminated the populations. M.napaulensis was suffered from human disturbance mainly from livestock grazing, plant harvesting and garbage pollution as the study area is an important tourist destination and pilgrimage site. Conservation of rare and endemic species such as M.napaulensis requires strong provisions restricting human activities and minimizing the impact from harvesting and grazing; and implementing habitat restoration and population augmentation programs.