This paper provides the information on nesting biology of 20 bird species in alpine shrub (4000-4700 m a.s.l.) or alpine meadow-wasteland habitats (4300-4700 m a.s.l.) in Lhasa region,Tibet.Of these species,three are ...This paper provides the information on nesting biology of 20 bird species in alpine shrub (4000-4700 m a.s.l.) or alpine meadow-wasteland habitats (4300-4700 m a.s.l.) in Lhasa region,Tibet.Of these species,three are endemic to the Tibetan plateau and 17 widespread in altitudes.The data on these taxa are all new to the high-altitude environments,especially the upper limit of their breeding distribution.A few species are firstly reported with respect to nesting information in the world.The study will contribute our knowledge for natural history of birds occurring in the harsh,extreme habitats.展开更多
The Qinghai-Tibet Plateau is one of the major sandy desertification regions of China. Based on the recent investigation on sandy desertification, this paper analyses the status such as the type, area, distribution and...The Qinghai-Tibet Plateau is one of the major sandy desertification regions of China. Based on the recent investigation on sandy desertification, this paper analyses the status such as the type, area, distribution and damage of sandy land desertification in the plateau. Through the analysis on the factors affecting sandy desertification in the region’s natural and socio-economic systems as well as the processes and their interrelations, it can be concluded that sandy desertification in the Qinghai-Tibet Plateau resulted from the combined actions of normal natural sand drift processes, natural sandy desertification processes caused by climatic changes and man-made sandy desertification caused by improper human activities. In addition, it also predicts the possible developmental trend including the increase in desertification area and the enhancement in desertification developmental degree with the exacerbation of the complex processes, and finally puts forward some strategic suggestions to combat sandy desertification in the coming years.展开更多
Enclosure is one of the most widely used management tools for degraded alpine grassland on the northern Tibetan Plateau, but the responses of different types of grassland to enclosure may vary, and research on these r...Enclosure is one of the most widely used management tools for degraded alpine grassland on the northern Tibetan Plateau, but the responses of different types of grassland to enclosure may vary, and research on these responses can provide a scientific basis for improving ecological conservation. This study took one site for each of three grassland types(alpine meadow, alpine steppe and alpine desert) on the northern Tibetan Plateau as examples, and explored the effects of enclosure on plant and soil nutrients by comparing differences in plant community biomass, leaf-soil nutrient content and their stoichiometry between samples from inside and outside the fence. The results showed that enclosure can significantly increase all aboveground biomass in these three grassland types, but it only increased the 10–20 cm underground biomass in the alpine desert. Enclosure also significantly increased the leaf nutrient content of the dominant plants and contents of total nitrogen(N), total potassium(K), and organic carbon(C) in 10–20 cm soil in alpine desert, thus changing the stoichiometry between C, N and P(phosphorus). However, enclosure significantly increased only the N content of dominant plant leaves in alpine steppe, while other nutrients and stoichiometries of both plant leaves and soil did not show significant differences in alpine meadow and alpine steppe. These results suggested that enclosure has differential effects on these three types of alpine grasslands on the northern Tibetan Plateau, and the alpine desert showed the most active ecological conservation in the responses of its soil and plant nutrients.展开更多
The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, i...The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese Loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese Loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese Loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene.展开更多
The aim of this study is to establish if the San Luis Potosi Plateau(SLPP), which is part of the southern edge of the Chihuahuan Desert, is generating desertification processes, indicating a progression of the desert ...The aim of this study is to establish if the San Luis Potosi Plateau(SLPP), which is part of the southern edge of the Chihuahuan Desert, is generating desertification processes, indicating a progression of the desert toward the central part of Mexico. Therefore, we analyzed the temporal evolution of four environmental indicators of desertification: Normalized Difference Vegetation Index(NDVI), Normalized Difference Water Index(NDWI), Iron Oxides Index(IO) and Surface Temperature(ST). Landsat TM images are used to cover a period from 1990 to 2011. A new equation of total balance is proposed to generate an image of the overall evolution of each factor which is applied to get a probability map of desertification. The evolution of NDVI, NDWI and IO shows a behavior almost stable over the time. In contrast, the ST shows a slight increase. The outcomes of this study confirm periods of vegetation re-greening and 8.80% of the SLPP has the highest probability to develop desertification. The most affected area is the portion west of the region, and the east and south are the least affected areas. The results suggest a slight advance of the desert, although most of the area doesn't have the necessary conditions to develop desertification.展开更多
基金the National Natural Sciences Foundation of China (Grant Nos. 39800016,30170156,30270216,30370241,30425036,30670337,and 30830019)
文摘This paper provides the information on nesting biology of 20 bird species in alpine shrub (4000-4700 m a.s.l.) or alpine meadow-wasteland habitats (4300-4700 m a.s.l.) in Lhasa region,Tibet.Of these species,three are endemic to the Tibetan plateau and 17 widespread in altitudes.The data on these taxa are all new to the high-altitude environments,especially the upper limit of their breeding distribution.A few species are firstly reported with respect to nesting information in the world.The study will contribute our knowledge for natural history of birds occurring in the harsh,extreme habitats.
基金Underthe auspices ofthe K ey ProjectofScience and Technology B ureau ofTibetA utonom ous R egion
文摘The Qinghai-Tibet Plateau is one of the major sandy desertification regions of China. Based on the recent investigation on sandy desertification, this paper analyses the status such as the type, area, distribution and damage of sandy land desertification in the plateau. Through the analysis on the factors affecting sandy desertification in the region’s natural and socio-economic systems as well as the processes and their interrelations, it can be concluded that sandy desertification in the Qinghai-Tibet Plateau resulted from the combined actions of normal natural sand drift processes, natural sandy desertification processes caused by climatic changes and man-made sandy desertification caused by improper human activities. In addition, it also predicts the possible developmental trend including the increase in desertification area and the enhancement in desertification developmental degree with the exacerbation of the complex processes, and finally puts forward some strategic suggestions to combat sandy desertification in the coming years.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19050502,XDA20010201)The National Key Research Projects of China(2017YFA0604801,2016YFC0502001)The National Natural Science Foundation of China(31770477)。
文摘Enclosure is one of the most widely used management tools for degraded alpine grassland on the northern Tibetan Plateau, but the responses of different types of grassland to enclosure may vary, and research on these responses can provide a scientific basis for improving ecological conservation. This study took one site for each of three grassland types(alpine meadow, alpine steppe and alpine desert) on the northern Tibetan Plateau as examples, and explored the effects of enclosure on plant and soil nutrients by comparing differences in plant community biomass, leaf-soil nutrient content and their stoichiometry between samples from inside and outside the fence. The results showed that enclosure can significantly increase all aboveground biomass in these three grassland types, but it only increased the 10–20 cm underground biomass in the alpine desert. Enclosure also significantly increased the leaf nutrient content of the dominant plants and contents of total nitrogen(N), total potassium(K), and organic carbon(C) in 10–20 cm soil in alpine desert, thus changing the stoichiometry between C, N and P(phosphorus). However, enclosure significantly increased only the N content of dominant plant leaves in alpine steppe, while other nutrients and stoichiometries of both plant leaves and soil did not show significant differences in alpine meadow and alpine steppe. These results suggested that enclosure has differential effects on these three types of alpine grasslands on the northern Tibetan Plateau, and the alpine desert showed the most active ecological conservation in the responses of its soil and plant nutrients.
基金supported by National Basic Research Program of China (Grants Nos. 2010CB833400, 2004CB720200)Innovation Program of Chinese Academy of Sciences (Grant No. KZCX2-YW-Q09-04)+1 种基金National Natural Science Foundation of China (Grants Nos. 41072142, 40921120406 and 40772116)State Key Laboratory of Loess and Quaternary Geology (SKLLQG)
文摘The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese Loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese Loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese Loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene.
基金Program for Professional Development of Professors(PRODEP)through the convention PROMEP/103.5/13/6575
文摘The aim of this study is to establish if the San Luis Potosi Plateau(SLPP), which is part of the southern edge of the Chihuahuan Desert, is generating desertification processes, indicating a progression of the desert toward the central part of Mexico. Therefore, we analyzed the temporal evolution of four environmental indicators of desertification: Normalized Difference Vegetation Index(NDVI), Normalized Difference Water Index(NDWI), Iron Oxides Index(IO) and Surface Temperature(ST). Landsat TM images are used to cover a period from 1990 to 2011. A new equation of total balance is proposed to generate an image of the overall evolution of each factor which is applied to get a probability map of desertification. The evolution of NDVI, NDWI and IO shows a behavior almost stable over the time. In contrast, the ST shows a slight increase. The outcomes of this study confirm periods of vegetation re-greening and 8.80% of the SLPP has the highest probability to develop desertification. The most affected area is the portion west of the region, and the east and south are the least affected areas. The results suggest a slight advance of the desert, although most of the area doesn't have the necessary conditions to develop desertification.
