We recorded 8 genera and over 30 species of bamboo in Sikkim of the reported 23 genera and 125 species in Indi＆ Thirty percent of bamboo species were recorded in tropical forests （0-900 m）, 40% of species in sub-tr...We recorded 8 genera and over 30 species of bamboo in Sikkim of the reported 23 genera and 125 species in Indi＆ Thirty percent of bamboo species were recorded in tropical forests （0-900 m）, 40% of species in sub-tropical forests （900-1,800 m）, 17% of species in temper- ate forests （1,800-2,700 m）, 9% of species in sub-alpine forests （2,700-3,500 m） and 4% of species in alpine vegetation （3,500-4,500 m）. Bamboo is used for various purposes and its versatility qualifies it to be a multiple-use alternative to timber, food for villagers and for tribal in particular. Bamboo is also equally important to Red Panda （Ailurusful- gens）, the state animal of Sikkim. We develop a list of bamboos occur- ring in Sikkim with their vernacular names, distributions and uses in the Himalayan state. However, more extensive study is required to fully describe the bamboo diversity of the Himalayan state.展开更多
Abstract： Estimation of evapotranspiration （ET） for mountain ecosystem is of absolute importance since it serves as an important component in balancing the hydrologic cycle. The present study evaluates the performa...Abstract： Estimation of evapotranspiration （ET） for mountain ecosystem is of absolute importance since it serves as an important component in balancing the hydrologic cycle. The present study evaluates the performance of original and location specific calibrated Hargreaves equation （HARG） with the estimates of Food and Agricultural Organization （FAO） Penman Monteith （PM） method for higher altitudes in East Sikkim, India. The results show that the uncalibrated HARG model underestimates ET0 by 0.35 mm day^-1 whereas the results are significantly improved by regional calibration of the model. In addition, this paper also presents the variability in the trajectory associated with the climatic variables with the changing climate in the study site. Non- parametric Mann-Kendall （MK） test was used to investigate and understand the mean monthly trend of eight climatic parameters including reference evapotranspiration （ET0） for the period of 1985 - 2009. Trend of ET0 was estimated for the calculations done by FAO PM equation. The outcomes of the trend analysis show significant increasing （p ≤ 0.05） trend represented by higher Z-values, through MK test, for net radiation （Rn）, maximum temperature （Tmax） and minimum temperature （Train）, especially in the first months of the year. Whereas, significant （0.01 ≥ p ≤0.05） decreasing trend in vapor pressure deficit （VPD） and precipitation （P） is observed throughout the year. Declining trend in sunshine duration, VPD and ET0 is found in spring （March - May） and monsoon （June - November） season. The result displays significant （0.01≤ p ≤0.05） decreasing ET0 trend between （June - December） except in July, exhibiting the positive relation with VPD followed by sunshine duration at the station. Overall, the study emphasizes the importance of trend analysis of ET0 and other climatic variables for efficient planning and managing the agricultural practices, in identifying the changes in the meteorological parameters and to accurately assess the hydrologic water balance of the hilly regions.展开更多
The Eastern Sikkim area forming a part of the Lesser Himalaya is located between 27°10′～27°30′N latitudes and 88°25′～88°40′E longitudes (750km 2). The previous workers agreed that a domal str...The Eastern Sikkim area forming a part of the Lesser Himalaya is located between 27°10′～27°30′N latitudes and 88°25′～88°40′E longitudes (750km 2). The previous workers agreed that a domal structure is present in Sikkim which is constituted by low to high grade metamorphic rocks characterised by inverted metamorphism. The rocks were repeatedly deformed and were metamorphosed at about 550 to 770℃ (550 to 750MPa). Geologically, the oldest rocks of Eastern Sikkim are represented by Darjeeling Formation showing medium to high grade metamorphism. It is followed by low grade Daling Formation which is characterised by tectonic wedges of Lingtse gneiss. The potassic syenite intrusive i.e. the Sikkim igneous formation is youngest rock type of the area. The Darjeeling Formation associated with amphibolite bands consists of kyanite\|sillimanite, staurolite and garnet zones, while the Daling Formation is characterised by low grade chloritoid and chlorite zones. Lingtse Formation is gneissic in which patches of retrograded and sheared garnet schists are present. Intrusions of potassic syenites (Sikkim Formation) occur in the form of oval and concordant bodies. The F 1, F 2 and F 3 folds are well developed in rocks of Eastern Sikkim area.. The F 1 folds are rootless, tightly isoclinal or reclined and highly obliterated in their attitude. The F 2 folds belong to class IC of Ramsay (1967). Their interlimb angles vary from 20～50 degrees. Intersection lineation due to S 0/S 1 and S 2 surfaces is parallel to the F 2 folds axis. Third generation structures are represented by open to moderately tight and kinked folds. Superimposition of F 3 folds on F 2 folds resulted into type II interference pattern of Ramsay (1967). Structural analysis of these folds have revealed that F 2 folds are non\|cylindrical. The kink or F 3 folds were possibly responsible for the formation of a megakink resembling with the domal structure. The repeatedly deformed rocks of Eastern Sikkim area were folded, faulted, sheared/thrusted during the Himalayan orogeny. The Main Central Thrust (M C T) is actually a ductile shear zone and was subjected to imbrication during later phases of F 2 folding.展开更多
The Himalayas hailed as the‘water towers of the world’feed many perennial rivers which form the lifeline of the Indian sub-continent.Climate change induced rising global temperatures and changing rainfall patterns a...The Himalayas hailed as the‘water towers of the world’feed many perennial rivers which form the lifeline of the Indian sub-continent.Climate change induced rising global temperatures and changing rainfall patterns are currently threatening the glaciers that feed the rivers.The combination of these factors is causing water stresses to a part of the world which is usually considered water abundant.Though there are some large-scale studies done in the Himalayas,regional analysis of changing rainfall patterns and their impacts on vegetation and agriculture is lacking.Here we focus on the Indian state of Sikkim located in the Eastern Himalayas to evaluate these issues using mixed methods.We use satellite data from PERSIANN and MODIS to characterise the regional rainfall,vegetation,and surface temperature trends between 2001 and 2019.While the analysis shows overall declining rainfall trends across most land cover classes,the trends in temperature are mostly positive for the period of study,with winter Land Surface Temperature(LST)values showing the largest area with marginally significant(p<0.1)positive trends.In contrast,such patterns are not observed for agriculture.However,the interviews corroborate that even agriculture is impacted,implying that the trends continue at finer spatial scales too.The lack of government support for adaptation and mitigation is also lamented placing the communities at a precarious position to continuing climate change.展开更多
Glacier response patterns at the catchment scale are highly heterogeneous and defined by a complex interplay of various dynamics and surface factors.Previous studies have explained heterogeneous responses in qualitati...Glacier response patterns at the catchment scale are highly heterogeneous and defined by a complex interplay of various dynamics and surface factors.Previous studies have explained heterogeneous responses in qualitative ways but quantitative assessment is lacking yet where an intrazone homogeneous climate assumption can be valid.Hence,in the current study,the reason for heterogeneous mass balance has been explained in quantitative methods using a multiple linear regression model in the Sikkim Himalayan region.At first,the topographical parameters are selected from previously published studies,then the most significant topographical and geomorphological parameters are selected with backward stepwise subset selection methods.Finally,the contributions of selected parameters are calculated by least square methods.The results show that,the magnitude of mass balance lies between-0.003±0.24 to-1.029±0.24 m.w.e.a^(-1) between 2000 and 2020 in the Sikkim Himalaya region.Also,the study shows that,out of the terminus type of the glacier,glacier area,debris cover,ice-mixed debris,slope,aspect,mean elevation,and snout elevation of the glaciers,only the terminus type and mean elevation of the glacier are significantly altering the glacier mass balance in the Sikkim Himalayan region.Mathematically,the mass loss is approximately 0.40 m.w.e.a^(-1) higher in the lake-terminating glaciers compared to the land-terminating glaciers in the same elevation zone.On the other hand,a thousand meters mean elevation drop is associated with 0.179 m.w.e.a-1of mass loss despite the terminus type of the glaciers.In the current study,the model using the terminus type of the glaciers and the mean elevation of the glaciers explains 76% of fluctuation of mass balance in the Sikkim Himalayan region.展开更多
Sikkim Himalaya hosts critical water resources such as glacial,rain,and snow-fed springs and lakes.Climate change is adversely affecting these resources in various ways,and elevation-dependent warming is prominent amo...Sikkim Himalaya hosts critical water resources such as glacial,rain,and snow-fed springs and lakes.Climate change is adversely affecting these resources in various ways,and elevation-dependent warming is prominent among them.This study is a discussion of the elevation-dependent warming(EDW),snowfall shift,and precipitation variability over Sikkim Himalaya using a high-resolution ERA5-land dataset.Furthermore,the findings show that the Sikkim Himalaya region is experiencing a warming trend from south to north.The majority of the Sikkim Himalayan region shows a declining trend in snowfall.A positive advancement in snowfall trend(at a rate of 1 mm per decade)has been noticed above 4500 meters.The S/P ratio indicates a shift in snowfall patterns,moving from lower elevations to much higher regions.This suggests that snowfall has also transitioned from Lachung and Lachen(3600 m)to higher elevated areas.Moreover,the seasonal shifting of snowfall in the recent decade is seen from January-March(JFM)to February-April(FMA).Subsequently,the preceding 21 years are being marked by a significant spatiotemporal change in temperature,precipitation,and snowfall.The potent negative correlation coefficient between temperature and snowfall(–0.9),temperature and S/P ratio(–0.5)suggested the changing nature of snowfall from solid to liquid,which further resulted in increased lower elevation precipitation.The entire Sikkim region is transitioning from a cold-dry to a warm-wet weather pattern.In the climate change scenario,a drop in the S/P ratio with altitude will continue to explain the rise in temperature over mountainous regions.展开更多
Myrmechis bakhimensis D. Maity,N. Pradhan & G. G. Maiti (Orchidaceae),a new species from Sikkim Himalaya,is described and illustrated. The new species most closely resembles M. japonica (Reichb.) Rolfe and M. chin...Myrmechis bakhimensis D. Maity,N. Pradhan & G. G. Maiti (Orchidaceae),a new species from Sikkim Himalaya,is described and illustrated. The new species most closely resembles M. japonica (Reichb.) Rolfe and M. chinensis Rolfe with similar shape and size of lamina and the “T”-shaped epichile,but differs by the perfectly glabrous and eciliate floral bract,5-nerved dorsal sepal,and emarginate,mucronate epichile.展开更多
The continuous collision of the Eurasian plate and the Indian plate has resulted in several earthquakes in the Himalayan region.The 6.9 Mw 2011 Sikkim earthquake,which caused immense damage to the built environment in...The continuous collision of the Eurasian plate and the Indian plate has resulted in several earthquakes in the Himalayan region.The 6.9 Mw 2011 Sikkim earthquake,which caused immense damage to the built environment in Sikkim,was triggered by an intraplate source on the overriding Eurasian plate.Strong ground motions from the earthquake were recorded at stations established by IIT Roorkee as part of the PESMOS program.In this paper,near-field and far-field ground motions from this earthquake were analyzed to evaluate their key characteristics and examine their time-frequency features by employing Fast Fourier Transforms(FFTs)and Continuous Wavelet Transforms(CWTs).A comparison between the ground motion parameters of near-field and far-field seismic waves highlights the distinct characteristics of near-field ground motions.Additionally,the impact of near-field and far-field ground motions on the seismic response of a code-compliant RC building is investigated.The results from the non-linear time history analyses indicate that the roof displacements,drift ratio and strain induced in the frame elements are less than the code-prescribed maximum limits.Further,the demand and capacity levels for the RC frame elements were evaluated to compute the performance ratios.The results indicate that the extensive damage to reinforced concrete buildings in the 2011 Sikkim quake was primarily due to the nonengineered nature of the structures and also due to the non-compliance of the built structures to the seismic design code provisions.展开更多
Landslide susceptibility map delineates the potential zones for landslides occurrence. The paper presents a statistical approach through spatial data analysis in GIS for landslide susceptibility mapping in parts of Si...Landslide susceptibility map delineates the potential zones for landslides occurrence. The paper presents a statistical approach through spatial data analysis in GIS for landslide susceptibility mapping in parts of Sikkim Himalaya. Six important causative factors for landslide occurrences were selected and corresponding thematic data layers were prepared in GIS. Topographic maps,satellite image,field data and published maps constitute the input data for thematic layer preparation. Numerical weights for different categories of these factors were determined based on a statistical approach and the weighted thematic layers were integrated in GIS environment to generate the landslide susceptibility map of the area. The landslide susceptibility map classifies the area into five different landslide susceptible zones i.e.,very high,high,moderate,low and very low. This map was validated using the existing landslide distribution in the area.展开更多
直角步甲属OrthogoniusMacleay在不丹和锡金原记录仅1种,即卵直角步甲O.opacusSchmidt G bel,本文补充了该种的一些分布记录,并描述了产自不丹和锡金的直角步甲属3新种,即喜直角步甲O.himalayicussp.nov.、杜氏直角步甲O.durelisp.nov....直角步甲属OrthogoniusMacleay在不丹和锡金原记录仅1种,即卵直角步甲O.opacusSchmidt G bel,本文补充了该种的一些分布记录,并描述了产自不丹和锡金的直角步甲属3新种,即喜直角步甲O.himalayicussp.nov.、杜氏直角步甲O.durelisp.nov.和长茎直角步甲O. longiphallussp.nov.,给出了该地区直角步甲属分种检索表。展开更多
The value-chain approach(VCA)was used for exploring how a niche crop,namely large cardamom(Amomum subulatum Roxb.),can be developed sustainably to increase incomes and enhance rural livelihoods in the mountains.Large ...The value-chain approach(VCA)was used for exploring how a niche crop,namely large cardamom(Amomum subulatum Roxb.),can be developed sustainably to increase incomes and enhance rural livelihoods in the mountains.Large cardamom is a high-value,agro-climatically suitable,and non-perishable spice crop grown in the Himalayan region.Originating in Sikkim,the crop is important to the local economy and is sold in both domestic and international markets;however,its production in India has been declining significantly in recent years.Using VCA and participatory methods of data collection the study helped elicit value chain actors’perspectives on various reasons for the decline as well as potential strategies to improve the cardamom value chain.The results present the multiple environmental and climatic(e.g.water stress),social(e.g.women participation)and institutional(e.g.lack of trust between actors)challenges and corresponding upgrading strategies.Through participatory multi-criteria analysis(MCA),the strategies were prioritized based on the overall preferences of multiple stakeholders.The analysis considered eight criteria and 25 options,or strategies,and found that that marketability and profitability were the most important criteria,and increasing cardamom production,the most important optiontrait.Stakeholder discussions along with sensitivity analysis also showed how these options could be implemented and revealed how criteria preferences can change with expert inputs.This combination of VCA and MCA,because it supports participatory decision-making and balances multiple dimensions of sustainable development,can be effectively deployed in planning for agricultural development in the mountains.展开更多
基金financially supported by the Horticulture and Cash Crop Development Department,Government of Sikkim,under National Bamboo Mission(NBM)
文摘We recorded 8 genera and over 30 species of bamboo in Sikkim of the reported 23 genera and 125 species in Indi＆ Thirty percent of bamboo species were recorded in tropical forests （0-900 m）, 40% of species in sub-tropical forests （900-1,800 m）, 17% of species in temper- ate forests （1,800-2,700 m）, 9% of species in sub-alpine forests （2,700-3,500 m） and 4% of species in alpine vegetation （3,500-4,500 m）. Bamboo is used for various purposes and its versatility qualifies it to be a multiple-use alternative to timber, food for villagers and for tribal in particular. Bamboo is also equally important to Red Panda （Ailurusful- gens）, the state animal of Sikkim. We develop a list of bamboos occur- ring in Sikkim with their vernacular names, distributions and uses in the Himalayan state. However, more extensive study is required to fully describe the bamboo diversity of the Himalayan state.
文摘Abstract： Estimation of evapotranspiration （ET） for mountain ecosystem is of absolute importance since it serves as an important component in balancing the hydrologic cycle. The present study evaluates the performance of original and location specific calibrated Hargreaves equation （HARG） with the estimates of Food and Agricultural Organization （FAO） Penman Monteith （PM） method for higher altitudes in East Sikkim, India. The results show that the uncalibrated HARG model underestimates ET0 by 0.35 mm day^-1 whereas the results are significantly improved by regional calibration of the model. In addition, this paper also presents the variability in the trajectory associated with the climatic variables with the changing climate in the study site. Non- parametric Mann-Kendall （MK） test was used to investigate and understand the mean monthly trend of eight climatic parameters including reference evapotranspiration （ET0） for the period of 1985 - 2009. Trend of ET0 was estimated for the calculations done by FAO PM equation. The outcomes of the trend analysis show significant increasing （p ≤ 0.05） trend represented by higher Z-values, through MK test, for net radiation （Rn）, maximum temperature （Tmax） and minimum temperature （Train）, especially in the first months of the year. Whereas, significant （0.01 ≥ p ≤0.05） decreasing trend in vapor pressure deficit （VPD） and precipitation （P） is observed throughout the year. Declining trend in sunshine duration, VPD and ET0 is found in spring （March - May） and monsoon （June - November） season. The result displays significant （0.01≤ p ≤0.05） decreasing ET0 trend between （June - December） except in July, exhibiting the positive relation with VPD followed by sunshine duration at the station. Overall, the study emphasizes the importance of trend analysis of ET0 and other climatic variables for efficient planning and managing the agricultural practices, in identifying the changes in the meteorological parameters and to accurately assess the hydrologic water balance of the hilly regions.
文摘The Eastern Sikkim area forming a part of the Lesser Himalaya is located between 27°10′～27°30′N latitudes and 88°25′～88°40′E longitudes (750km 2). The previous workers agreed that a domal structure is present in Sikkim which is constituted by low to high grade metamorphic rocks characterised by inverted metamorphism. The rocks were repeatedly deformed and were metamorphosed at about 550 to 770℃ (550 to 750MPa). Geologically, the oldest rocks of Eastern Sikkim are represented by Darjeeling Formation showing medium to high grade metamorphism. It is followed by low grade Daling Formation which is characterised by tectonic wedges of Lingtse gneiss. The potassic syenite intrusive i.e. the Sikkim igneous formation is youngest rock type of the area. The Darjeeling Formation associated with amphibolite bands consists of kyanite\|sillimanite, staurolite and garnet zones, while the Daling Formation is characterised by low grade chloritoid and chlorite zones. Lingtse Formation is gneissic in which patches of retrograded and sheared garnet schists are present. Intrusions of potassic syenites (Sikkim Formation) occur in the form of oval and concordant bodies. The F 1, F 2 and F 3 folds are well developed in rocks of Eastern Sikkim area.. The F 1 folds are rootless, tightly isoclinal or reclined and highly obliterated in their attitude. The F 2 folds belong to class IC of Ramsay (1967). Their interlimb angles vary from 20～50 degrees. Intersection lineation due to S 0/S 1 and S 2 surfaces is parallel to the F 2 folds axis. Third generation structures are represented by open to moderately tight and kinked folds. Superimposition of F 3 folds on F 2 folds resulted into type II interference pattern of Ramsay (1967). Structural analysis of these folds have revealed that F 2 folds are non\|cylindrical. The kink or F 3 folds were possibly responsible for the formation of a megakink resembling with the domal structure. The repeatedly deformed rocks of Eastern Sikkim area were folded, faulted, sheared/thrusted during the Himalayan orogeny. The Main Central Thrust (M C T) is actually a ductile shear zone and was subjected to imbrication during later phases of F 2 folding.
基金Ashoka Trust for Research in Ecology and the Environment,Bangalore for providing the financial support towards field work in Sikkim。
文摘The Himalayas hailed as the‘water towers of the world’feed many perennial rivers which form the lifeline of the Indian sub-continent.Climate change induced rising global temperatures and changing rainfall patterns are currently threatening the glaciers that feed the rivers.The combination of these factors is causing water stresses to a part of the world which is usually considered water abundant.Though there are some large-scale studies done in the Himalayas,regional analysis of changing rainfall patterns and their impacts on vegetation and agriculture is lacking.Here we focus on the Indian state of Sikkim located in the Eastern Himalayas to evaluate these issues using mixed methods.We use satellite data from PERSIANN and MODIS to characterise the regional rainfall,vegetation,and surface temperature trends between 2001 and 2019.While the analysis shows overall declining rainfall trends across most land cover classes,the trends in temperature are mostly positive for the period of study,with winter Land Surface Temperature(LST)values showing the largest area with marginally significant(p<0.1)positive trends.In contrast,such patterns are not observed for agriculture.However,the interviews corroborate that even agriculture is impacted,implying that the trends continue at finer spatial scales too.The lack of government support for adaptation and mitigation is also lamented placing the communities at a precarious position to continuing climate change.
文摘Glacier response patterns at the catchment scale are highly heterogeneous and defined by a complex interplay of various dynamics and surface factors.Previous studies have explained heterogeneous responses in qualitative ways but quantitative assessment is lacking yet where an intrazone homogeneous climate assumption can be valid.Hence,in the current study,the reason for heterogeneous mass balance has been explained in quantitative methods using a multiple linear regression model in the Sikkim Himalayan region.At first,the topographical parameters are selected from previously published studies,then the most significant topographical and geomorphological parameters are selected with backward stepwise subset selection methods.Finally,the contributions of selected parameters are calculated by least square methods.The results show that,the magnitude of mass balance lies between-0.003±0.24 to-1.029±0.24 m.w.e.a^(-1) between 2000 and 2020 in the Sikkim Himalaya region.Also,the study shows that,out of the terminus type of the glacier,glacier area,debris cover,ice-mixed debris,slope,aspect,mean elevation,and snout elevation of the glaciers,only the terminus type and mean elevation of the glacier are significantly altering the glacier mass balance in the Sikkim Himalayan region.Mathematically,the mass loss is approximately 0.40 m.w.e.a^(-1) higher in the lake-terminating glaciers compared to the land-terminating glaciers in the same elevation zone.On the other hand,a thousand meters mean elevation drop is associated with 0.179 m.w.e.a-1of mass loss despite the terminus type of the glaciers.In the current study,the model using the terminus type of the glaciers and the mean elevation of the glaciers explains 76% of fluctuation of mass balance in the Sikkim Himalayan region.
文摘Sikkim Himalaya hosts critical water resources such as glacial,rain,and snow-fed springs and lakes.Climate change is adversely affecting these resources in various ways,and elevation-dependent warming is prominent among them.This study is a discussion of the elevation-dependent warming(EDW),snowfall shift,and precipitation variability over Sikkim Himalaya using a high-resolution ERA5-land dataset.Furthermore,the findings show that the Sikkim Himalaya region is experiencing a warming trend from south to north.The majority of the Sikkim Himalayan region shows a declining trend in snowfall.A positive advancement in snowfall trend(at a rate of 1 mm per decade)has been noticed above 4500 meters.The S/P ratio indicates a shift in snowfall patterns,moving from lower elevations to much higher regions.This suggests that snowfall has also transitioned from Lachung and Lachen(3600 m)to higher elevated areas.Moreover,the seasonal shifting of snowfall in the recent decade is seen from January-March(JFM)to February-April(FMA).Subsequently,the preceding 21 years are being marked by a significant spatiotemporal change in temperature,precipitation,and snowfall.The potent negative correlation coefficient between temperature and snowfall(–0.9),temperature and S/P ratio(–0.5)suggested the changing nature of snowfall from solid to liquid,which further resulted in increased lower elevation precipitation.The entire Sikkim region is transitioning from a cold-dry to a warm-wet weather pattern.In the climate change scenario,a drop in the S/P ratio with altitude will continue to explain the rise in temperature over mountainous regions.
文摘Myrmechis bakhimensis D. Maity,N. Pradhan & G. G. Maiti (Orchidaceae),a new species from Sikkim Himalaya,is described and illustrated. The new species most closely resembles M. japonica (Reichb.) Rolfe and M. chinensis Rolfe with similar shape and size of lamina and the “T”-shaped epichile,but differs by the perfectly glabrous and eciliate floral bract,5-nerved dorsal sepal,and emarginate,mucronate epichile.
文摘The continuous collision of the Eurasian plate and the Indian plate has resulted in several earthquakes in the Himalayan region.The 6.9 Mw 2011 Sikkim earthquake,which caused immense damage to the built environment in Sikkim,was triggered by an intraplate source on the overriding Eurasian plate.Strong ground motions from the earthquake were recorded at stations established by IIT Roorkee as part of the PESMOS program.In this paper,near-field and far-field ground motions from this earthquake were analyzed to evaluate their key characteristics and examine their time-frequency features by employing Fast Fourier Transforms(FFTs)and Continuous Wavelet Transforms(CWTs).A comparison between the ground motion parameters of near-field and far-field seismic waves highlights the distinct characteristics of near-field ground motions.Additionally,the impact of near-field and far-field ground motions on the seismic response of a code-compliant RC building is investigated.The results from the non-linear time history analyses indicate that the roof displacements,drift ratio and strain induced in the frame elements are less than the code-prescribed maximum limits.Further,the demand and capacity levels for the RC frame elements were evaluated to compute the performance ratios.The results indicate that the extensive damage to reinforced concrete buildings in the 2011 Sikkim quake was primarily due to the nonengineered nature of the structures and also due to the non-compliance of the built structures to the seismic design code provisions.
文摘Landslide susceptibility map delineates the potential zones for landslides occurrence. The paper presents a statistical approach through spatial data analysis in GIS for landslide susceptibility mapping in parts of Sikkim Himalaya. Six important causative factors for landslide occurrences were selected and corresponding thematic data layers were prepared in GIS. Topographic maps,satellite image,field data and published maps constitute the input data for thematic layer preparation. Numerical weights for different categories of these factors were determined based on a statistical approach and the weighted thematic layers were integrated in GIS environment to generate the landslide susceptibility map of the area. The landslide susceptibility map classifies the area into five different landslide susceptible zones i.e.,very high,high,moderate,low and very low. This map was validated using the existing landslide distribution in the area.
文摘直角步甲属OrthogoniusMacleay在不丹和锡金原记录仅1种,即卵直角步甲O.opacusSchmidt G bel,本文补充了该种的一些分布记录,并描述了产自不丹和锡金的直角步甲属3新种,即喜直角步甲O.himalayicussp.nov.、杜氏直角步甲O.durelisp.nov.和长茎直角步甲O. longiphallussp.nov.,给出了该地区直角步甲属分种检索表。
基金funding support from Himalayan Adaptation, Water and Resilience (HI-AWARE) Research Consortium
文摘The value-chain approach(VCA)was used for exploring how a niche crop,namely large cardamom(Amomum subulatum Roxb.),can be developed sustainably to increase incomes and enhance rural livelihoods in the mountains.Large cardamom is a high-value,agro-climatically suitable,and non-perishable spice crop grown in the Himalayan region.Originating in Sikkim,the crop is important to the local economy and is sold in both domestic and international markets;however,its production in India has been declining significantly in recent years.Using VCA and participatory methods of data collection the study helped elicit value chain actors’perspectives on various reasons for the decline as well as potential strategies to improve the cardamom value chain.The results present the multiple environmental and climatic(e.g.water stress),social(e.g.women participation)and institutional(e.g.lack of trust between actors)challenges and corresponding upgrading strategies.Through participatory multi-criteria analysis(MCA),the strategies were prioritized based on the overall preferences of multiple stakeholders.The analysis considered eight criteria and 25 options,or strategies,and found that that marketability and profitability were the most important criteria,and increasing cardamom production,the most important optiontrait.Stakeholder discussions along with sensitivity analysis also showed how these options could be implemented and revealed how criteria preferences can change with expert inputs.This combination of VCA and MCA,because it supports participatory decision-making and balances multiple dimensions of sustainable development,can be effectively deployed in planning for agricultural development in the mountains.
