In order to advance land use and land cover change（LUCC） research in Nepal, it is essential to reconstruct both the spatiotemporal distribution of agricultural land cover as well as scenarios that can explain these ...In order to advance land use and land cover change（LUCC） research in Nepal, it is essential to reconstruct both the spatiotemporal distribution of agricultural land cover as well as scenarios that can explain these changes at the national and regional levels. Because of rapid population growth, the status of agricultural land in Nepal has changed markedly over the last 100 years. Historical data is used in this study, encompassing soils, populations, climatic variables, and topography. Data were revised to a series of 30 m grid cells utilized for agricultural land suitability and allocation models and were analyzed using a suite of advanced geographical tools. Our reconstructions for the spatiotemporal distribution of agricultural land in Nepal reveal an increasing trend between 1910 and 2010（from 151.2 × 10^2 km^2 to 438.8 × 10^2 km^2）. This expanded rate of increase in agricultural land has varied between different eco, physiographic, and altitudinal regions of the country, significantly driven by population changes and policies over the period of this investigation. The historical dataset presented in this paper fills an existing gap in studies of agricultural land change and can be applied to other carbon cycle and climate modeling studies, as well as to impact assessments of agricultural land change in Nepal.展开更多
Objective:To determine the present status of plant communities and their possible association with the habitat in Malam Jabba,Swat,Pakistan.Methods:A study on the phytoecology was conducted in various ecologically imp...Objective:To determine the present status of plant communities and their possible association with the habitat in Malam Jabba,Swat,Pakistan.Methods:A study on the phytoecology was conducted in various ecologically important sites of Malam Jabba,Swat,Pakistan from 2002 to 2004.The altitude of these sites ranged from 1200 m to.1200 m.Quadrat method was used for evaluation of plants communities and the data on these attributes was converted to relative values. The plant communities were named after 3 leading species with highest importance values. Biological spectrum of the flora based on the life form was prepared by following Raunkiar's life form classes.Results:The floristic composition and structure of the study area were found to be 200 species belonging to 75 families.Asteraceae,Lamiaceae and Poaceae were important families in the study area.The biological spectrum showed that therophytic and hemicrytophytic life form and micro-nonophyllous leaf sizes were dominant in the area.The air and soil temperatures were decreasing with increasing elevation.Both the air and soil temperatures were relatively higher in south slopes than on the northeast slopes.The vegetation analysis of the area indicated eleven plant communities around the area.The present vegetation is the relics of moist temperate coniferous forest in the area.The communities reflect highly deteriorated conditions. Both the structure and composition of the surrounding vegetation were associated with the types of habitats.Conclusions:The conservation of the remaining populations of the reported communities will be best achieved by proper time of sustainable harvesting.It is only possible with the participation of local communities.展开更多
On both west and east sides of sub-Antarctic Marion Island (47oS, 38oE), total Na and exchangeable Na, Mg and K concentrations in the soil decline with increasing distance inland and altitude, related to a decrease in...On both west and east sides of sub-Antarctic Marion Island (47oS, 38oE), total Na and exchangeable Na, Mg and K concentrations in the soil decline with increasing distance inland and altitude, related to a decrease in the intensity of seaspray deposition. On the east side, the coastal plain is wide and slopes gently up to the mountainous interior and total C, total N and soil moisture content all decrease significantly, whereas bulk density increases significantly, as one moves away from the sea, reflecting a gradual change from organic, wet, low bulk density peats characteristic of low-land coastal regions to mineral, dry, high bulk density volcanic soils characteristic of inland areas. On the west side, the narrow coastal plain is bounded by an escarpment that rises up very steeply to the highland interior. There, sampling was largely restricted to the coastal plain (soils are rare on the escarpment and interior) and did not cover the same transition from organic to mineral soils as on the east side. Hence, total C, total N and bulk density did not change significantly with increasing distance inland on the west side. Most total Mg is in the mineral fraction of the soil, with a lesser contribution by organic, exchangeable and soil solution forms of Mg. On the east side the gradual transition from highly organic peats to very mineral soils results in an increase in total Mg going inland, but on the west, where there was not this change in soil minerality, total Mg decreased with increasing distance inland, reflecting the decreasing intensity of seaspray. Once the between-side differences in the influence of altitude and distance from the sea are accounted for, there are significant differences in soil chemical composition between the two sides of the island. Overall, west side soils are more influenced by both seaspray and the parent volcanic basalts than are east side soils.展开更多
Objective:To establish an efficacious and efficient surveillance method of Armigeres(Ar.)subalbatus,a known filarial vector,surviving in forest habitats to estimate realistic population density and assess the impact o...Objective:To establish an efficacious and efficient surveillance method of Armigeres(Ar.)subalbatus,a known filarial vector,surviving in forest habitats to estimate realistic population density and assess the impact of altitudinal variations on the efficacy of the trap.Methods:In the study,12 locations in areas with an altitudinal range from 82 m to 920 m were selected in three reserve forests for night sampling of adult Ar.subalbatus mosquito using standard chemical lure based BG-Sentinel traps and CDC-light traps in pairs.Effects of locations and time were estimated on the efficacy of traps as mosquito density using multifactor analysis of variance for significant differences.Impact of altitudinal variations on the efficacy of traps was assessed using multiple regression with slope comparison.Results:BG-Sentinel trap collected significantly more adult Ar.subalbatus,4.43 folds in Gorumara NP,5.19 folds in Neora Valley NP and 12.10 folds in Mahananda WLS than the CDC-light trap irrespective to locations.BG-Sentinel traps were tolerant of altitudinal variations(80 m-170 m)and showed no significant relationship between density and altitudes in contrast to CDC-light traps which showed a significant negative impact on capturing efficacy with increase in altitudes(P<0.001).Conclusions:The study suggests that BG-Sentinel traps can be used effectively and efficiently to collect more Ar.subalbatus mosquitoes during night time in comparison to CDC-light trap under complex climatic conditions of forest and variable altitudes.展开更多
基金National Natural Science Foundation of China,No.41371120International Partnership Program of Chinese Academy of Sciences,No.131C11KYSB20160061The Chinese Academy of Sciences-The World Academy of Sciences(CAS-TWAS)President’s Fellowship Program for PhD Study
文摘In order to advance land use and land cover change（LUCC） research in Nepal, it is essential to reconstruct both the spatiotemporal distribution of agricultural land cover as well as scenarios that can explain these changes at the national and regional levels. Because of rapid population growth, the status of agricultural land in Nepal has changed markedly over the last 100 years. Historical data is used in this study, encompassing soils, populations, climatic variables, and topography. Data were revised to a series of 30 m grid cells utilized for agricultural land suitability and allocation models and were analyzed using a suite of advanced geographical tools. Our reconstructions for the spatiotemporal distribution of agricultural land in Nepal reveal an increasing trend between 1910 and 2010（from 151.2 × 10^2 km^2 to 438.8 × 10^2 km^2）. This expanded rate of increase in agricultural land has varied between different eco, physiographic, and altitudinal regions of the country, significantly driven by population changes and policies over the period of this investigation. The historical dataset presented in this paper fills an existing gap in studies of agricultural land change and can be applied to other carbon cycle and climate modeling studies, as well as to impact assessments of agricultural land change in Nepal.
基金Supported by Excellent Centre of Biotechnology Resaerch of KingSaud University.Riyadh.Saudi.Arabia(No.AR-26-44)
文摘Objective:To determine the present status of plant communities and their possible association with the habitat in Malam Jabba,Swat,Pakistan.Methods:A study on the phytoecology was conducted in various ecologically important sites of Malam Jabba,Swat,Pakistan from 2002 to 2004.The altitude of these sites ranged from 1200 m to.1200 m.Quadrat method was used for evaluation of plants communities and the data on these attributes was converted to relative values. The plant communities were named after 3 leading species with highest importance values. Biological spectrum of the flora based on the life form was prepared by following Raunkiar's life form classes.Results:The floristic composition and structure of the study area were found to be 200 species belonging to 75 families.Asteraceae,Lamiaceae and Poaceae were important families in the study area.The biological spectrum showed that therophytic and hemicrytophytic life form and micro-nonophyllous leaf sizes were dominant in the area.The air and soil temperatures were decreasing with increasing elevation.Both the air and soil temperatures were relatively higher in south slopes than on the northeast slopes.The vegetation analysis of the area indicated eleven plant communities around the area.The present vegetation is the relics of moist temperate coniferous forest in the area.The communities reflect highly deteriorated conditions. Both the structure and composition of the surrounding vegetation were associated with the types of habitats.Conclusions:The conservation of the remaining populations of the reported communities will be best achieved by proper time of sustainable harvesting.It is only possible with the participation of local communities.
文摘On both west and east sides of sub-Antarctic Marion Island (47oS, 38oE), total Na and exchangeable Na, Mg and K concentrations in the soil decline with increasing distance inland and altitude, related to a decrease in the intensity of seaspray deposition. On the east side, the coastal plain is wide and slopes gently up to the mountainous interior and total C, total N and soil moisture content all decrease significantly, whereas bulk density increases significantly, as one moves away from the sea, reflecting a gradual change from organic, wet, low bulk density peats characteristic of low-land coastal regions to mineral, dry, high bulk density volcanic soils characteristic of inland areas. On the west side, the narrow coastal plain is bounded by an escarpment that rises up very steeply to the highland interior. There, sampling was largely restricted to the coastal plain (soils are rare on the escarpment and interior) and did not cover the same transition from organic to mineral soils as on the east side. Hence, total C, total N and bulk density did not change significantly with increasing distance inland on the west side. Most total Mg is in the mineral fraction of the soil, with a lesser contribution by organic, exchangeable and soil solution forms of Mg. On the east side the gradual transition from highly organic peats to very mineral soils results in an increase in total Mg going inland, but on the west, where there was not this change in soil minerality, total Mg decreased with increasing distance inland, reflecting the decreasing intensity of seaspray. Once the between-side differences in the influence of altitude and distance from the sea are accounted for, there are significant differences in soil chemical composition between the two sides of the island. Overall, west side soils are more influenced by both seaspray and the parent volcanic basalts than are east side soils.
基金Dr.Kailash Chandra,Director,Zoological Survey of India(ZSI),Ministry of Environment,Forest and Climate Change(MoEFCC),Govt.of India,for providing funding and logistic support.
文摘Objective:To establish an efficacious and efficient surveillance method of Armigeres(Ar.)subalbatus,a known filarial vector,surviving in forest habitats to estimate realistic population density and assess the impact of altitudinal variations on the efficacy of the trap.Methods:In the study,12 locations in areas with an altitudinal range from 82 m to 920 m were selected in three reserve forests for night sampling of adult Ar.subalbatus mosquito using standard chemical lure based BG-Sentinel traps and CDC-light traps in pairs.Effects of locations and time were estimated on the efficacy of traps as mosquito density using multifactor analysis of variance for significant differences.Impact of altitudinal variations on the efficacy of traps was assessed using multiple regression with slope comparison.Results:BG-Sentinel trap collected significantly more adult Ar.subalbatus,4.43 folds in Gorumara NP,5.19 folds in Neora Valley NP and 12.10 folds in Mahananda WLS than the CDC-light trap irrespective to locations.BG-Sentinel traps were tolerant of altitudinal variations(80 m-170 m)and showed no significant relationship between density and altitudes in contrast to CDC-light traps which showed a significant negative impact on capturing efficacy with increase in altitudes(P<0.001).Conclusions:The study suggests that BG-Sentinel traps can be used effectively and efficiently to collect more Ar.subalbatus mosquitoes during night time in comparison to CDC-light trap under complex climatic conditions of forest and variable altitudes.
