The natural upper boundary of a forest（forest line） in mountain environments is an indicator of climate conditions. An increase in global average temperatures has resulted in an upward advance of the forest line. Th...The natural upper boundary of a forest（forest line） in mountain environments is an indicator of climate conditions. An increase in global average temperatures has resulted in an upward advance of the forest line. This advance may result in fragmentation of the alpine ecosystem and a loss of biodiversity. Therefore, it is important to identify potential areas where current forests can advance under scenarios of future climate change. I used expert knowledge and cartographic modeling to create a hybrid cartographic model considering five topographic variables to predict areas where forest line can expand in the future.The prediction accuracy of the model is around 82%. The model is able to predict areas above the current forest line that are suitable or unsuitable for future forest advance.Further inclusion of high-resolution satellite imagery and digital elevation models, as well as field-based information into the model can help to improve the model accuracy.展开更多
The article is based on collection of small terrestrial mammals(Soriculus nigrescens,Episoriculus caudatus, Neodon sikimensis,Alticola stoliczkanus, Niviventer eha and Ochotona roylei) collected in the Barun Valley, e...The article is based on collection of small terrestrial mammals(Soriculus nigrescens,Episoriculus caudatus, Neodon sikimensis,Alticola stoliczkanus, Niviventer eha and Ochotona roylei) collected in the Barun Valley, east Nepal in the pre-monsoon period of 1973.Zoogeographic and ecological characteristics and altitudinal stratification of these species are analysed, depending both on abiotic(geomorphological and climatic) and biotic(vegetation, and human presence and activities)factors. All the captured mammals were examined for ecto- and endoparasities. Infestations of Trombiculid mites and Ixodid ticks were tightly linked to the local habitat where these ectoparasites must survive during their nonparasitic phase. Analysis of their occurrence completes the reconstruction of migration routes during the expansion of small mammals into the Barun Valley and the exacerbating influence of human activities(summer pasturing,mountaineering expeditions and trekking parties).An indicator of anthropogenic influence was the occurrence of synantropic flies. The potential medical importance of these findings is discussed.It is assumed a possible occurrence of arboviruses transmitted by ticks and also rickettsioses(transmitted by ticks and chigger mites). As far bacteriological infections, plague cannot be excluded.展开更多
Characterized by obvious altitudinal variation,habitat complexity,and diversity in land cover,the Mt.Qomolangma region within the central Himalayas is one of the most sensitive areas to climate change in the world.At ...Characterized by obvious altitudinal variation,habitat complexity,and diversity in land cover,the Mt.Qomolangma region within the central Himalayas is one of the most sensitive areas to climate change in the world.At the same time,because the Mt.Qomolangma region possesses the most complete natural vertical spectrum in the world,it is also an ideal place to study the vertical structure of alpine land cover.In this study,land cover data for 2010 along with digital elevation model data were used to define three methods for dividing the northern and southern slopes in the Mt.Qomolangma region,i.e.,the ridgeline method,the sample transect method,and the sector method.The altitudinal distributions of different land cover types were then investigated for both the northern and southern slopes of the Mt.Qomolangma region by using the above three division methods along with ArcGIS and MATLAB tools.The results indicate that the land cover in the study region was characterized by obviously vertical zonation with the south-six and north-four pattern of vertical spectrum that reflected both the natural vertical structure of vegetation and the effects of human activities.From low to high elevation,the main land cover types were forests,grasslands,sparse vegetation,bare land,and glacler/snow cover.The compositions and distributions of land cover types differed significantly between the northern and southern slopes;the southern slope exhibited more complex land cover distributions with wider elevation ranges than the northern slope.The area proportion of each land cover type also varied with elevation.Accordingly,the vertical distribution patterns of different land cover types on the southern and northern slopes could be divided into four categories,with glaciers/snow cover,sparse vegetation,and grasslands conforming to unimodal distributions.The distribution of bare land followed a unimodal pattern on the southern slope but a bimodal pattern on the northern slope.Finally,the use of different slope division methods produced simi展开更多
文摘The natural upper boundary of a forest（forest line） in mountain environments is an indicator of climate conditions. An increase in global average temperatures has resulted in an upward advance of the forest line. This advance may result in fragmentation of the alpine ecosystem and a loss of biodiversity. Therefore, it is important to identify potential areas where current forests can advance under scenarios of future climate change. I used expert knowledge and cartographic modeling to create a hybrid cartographic model considering five topographic variables to predict areas where forest line can expand in the future.The prediction accuracy of the model is around 82%. The model is able to predict areas above the current forest line that are suitable or unsuitable for future forest advance.Further inclusion of high-resolution satellite imagery and digital elevation models, as well as field-based information into the model can help to improve the model accuracy.
文摘The article is based on collection of small terrestrial mammals(Soriculus nigrescens,Episoriculus caudatus, Neodon sikimensis,Alticola stoliczkanus, Niviventer eha and Ochotona roylei) collected in the Barun Valley, east Nepal in the pre-monsoon period of 1973.Zoogeographic and ecological characteristics and altitudinal stratification of these species are analysed, depending both on abiotic(geomorphological and climatic) and biotic(vegetation, and human presence and activities)factors. All the captured mammals were examined for ecto- and endoparasities. Infestations of Trombiculid mites and Ixodid ticks were tightly linked to the local habitat where these ectoparasites must survive during their nonparasitic phase. Analysis of their occurrence completes the reconstruction of migration routes during the expansion of small mammals into the Barun Valley and the exacerbating influence of human activities(summer pasturing,mountaineering expeditions and trekking parties).An indicator of anthropogenic influence was the occurrence of synantropic flies. The potential medical importance of these findings is discussed.It is assumed a possible occurrence of arboviruses transmitted by ticks and also rickettsioses(transmitted by ticks and chigger mites). As far bacteriological infections, plague cannot be excluded.
基金National Natural Science Foundation of China.No.41761144081The Priority Research Program of Chinese Academy of Sciences,No.XDA20040201The Second Tibetan Plateau Scientific Expedition and Research,No.2019QZKK0603。
文摘Characterized by obvious altitudinal variation,habitat complexity,and diversity in land cover,the Mt.Qomolangma region within the central Himalayas is one of the most sensitive areas to climate change in the world.At the same time,because the Mt.Qomolangma region possesses the most complete natural vertical spectrum in the world,it is also an ideal place to study the vertical structure of alpine land cover.In this study,land cover data for 2010 along with digital elevation model data were used to define three methods for dividing the northern and southern slopes in the Mt.Qomolangma region,i.e.,the ridgeline method,the sample transect method,and the sector method.The altitudinal distributions of different land cover types were then investigated for both the northern and southern slopes of the Mt.Qomolangma region by using the above three division methods along with ArcGIS and MATLAB tools.The results indicate that the land cover in the study region was characterized by obviously vertical zonation with the south-six and north-four pattern of vertical spectrum that reflected both the natural vertical structure of vegetation and the effects of human activities.From low to high elevation,the main land cover types were forests,grasslands,sparse vegetation,bare land,and glacler/snow cover.The compositions and distributions of land cover types differed significantly between the northern and southern slopes;the southern slope exhibited more complex land cover distributions with wider elevation ranges than the northern slope.The area proportion of each land cover type also varied with elevation.Accordingly,the vertical distribution patterns of different land cover types on the southern and northern slopes could be divided into four categories,with glaciers/snow cover,sparse vegetation,and grasslands conforming to unimodal distributions.The distribution of bare land followed a unimodal pattern on the southern slope but a bimodal pattern on the northern slope.Finally,the use of different slope division methods produced simi
