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Abstract: Four sets of remote sensing images from 1987, 1994, 2000, and 2006, 50 years of meteorological and soil moisture data corresponding to different desertified lands were combined with populations and livestock data to analyze the process and cause of desertification in a portion of the Qinghai–Tibetan Plateau (QTP). It showed that surface soil temperature in the region has increased at an average rate of 0.6 °C per decade between 1980 and 2005, the thawing days on the surface have increased by 60 days from 1983 to 2001, and the depth of the seasonal thawing layer has increased by 54 cm, 102 cm and 77 cm in April, May and June, respectively, from 1983 to 2003. As a result, the upper soil layer has become drier due to the thickening active layer and soil water infiltration. These changes, in turn, have inhibited the growth of alpine meadow vegetation that has shallow root systems. It is concluded that climate warming and permafrost thawing have caused desertification in grazing regions of the Qinghai–Tibetan Plateau (QTP). [Copyright &y& Elsevier]

Four new species, Abrolophus quadrapexicis Xu & Jin sp. nov., Grandjeanella dianensis Xu & Jin sp. nov., Leptus (Leptus) trisolenidionus Xu & Jin sp. nov. and Hirstiosoma tibetensis Xu & Jin sp. nov. are described and illustrated based on larvae. The species Hirstiosoma sadafae (Amin, Khanjani & Nadri) comb. nov. is transferred from the genus Sphaerotarsus to Hirstiosoma based on gnathosoma with two pairs barbed hypostomalae (as and bs), as and bs almost equal in length. H. tibetensissp. nov. and G. dianensissp. nov. are from the Tibetan Plateau (Qinghai-Tibet Plateau), a unique geographical unit of the highest altitude in the world. The described H. tibetensissp. nov. from the Tibetan Plateau represents a newly recorded subfamily from China, namely Hirstiosomatinae (Smarididae) with the genus Hirstiosoma. The genus Grandjeanella including six species distributed in Australia, New Zealand and Indonesia (Sulawesi), is new to China and the Eurasian continent as G. dianensissp. nov. found in the southern Tibetan Plateau (Gaoligongshan National Natural Reserve). In China Abrolophus has been known from the Oriental realm, A. quadrapexicissp. nov. makes it cover both the Palaearctic and Oriental realm of China. L. (L.) trisolenidionussp. nov. belongs to the phalangii species group and torresianus species subgroup, which contains three species previously known in Oceania (Australia) and South America (French Guiana) and here is the first report in Asia (China). [ABSTRACT FROM AUTHOR]

The fluctuation of the water level in a reservoir may induce various types of slope movements. Some of these movements are new, whereas others are old but reactivated. Many ancient landslide accumulations are distributed in the deep valleys of the eastern Qinghai-Tibet Plateau margin in China and will likely be reactivated after the completion of reservoirs and pose a risk to reservoirs, dams, facilities, and towns near mountainous areas. The Shuangjiaping ancient landslide, located in the Dadu River, Sichuan Province, China, is an example of this case. Since August 2010, the western part of the accumulation body has seen the gradual appearance of deformations. The Pubugou reservoir water level rises and inundates the front edge of the accumulation body, thus threatening the safety of the national highway G108 and 37 houses on it. This study is based on field work investigation, drilling work, aerial photography, and profile survey. The site-scale investigation shows that the deformation area is only a part of an ancient landslide accumulation, with an area of approximately 50.4 × 10 m and a volume of ca. 956 × 10 m. Boundary and deposit characteristics of landslide accumulation are specified, which could be divided into four zones, namely, zones A and C, which are an avalanche accumulation area mainly composed of large blocks with diameter ranging from 1 to 3 m (some blocks have a diameter ranging from 5 to 10 m), zone B, a residual integrated rock mass accumulation area with 'fake bedrock,' and zone D, a fine material accumulation area. A conceptual model is proposed to explain the mechanism and sliding process of this ancient landslide. The model includes translational sliding, stopping and hanging in air, avalanche accumulating, and transforming. The saltation of topography, material structure, and kinematic characteristics is the evidence used to identify the ancient landslide in deeply incised mountain areas. The current activity is found to be a surficial deposit displacement, and the whole landslide accumulation is stable or quasi-stable. [ABSTRACT FROM AUTHOR]

Partitioning evapotranspiration ( ET ) into soil evaporation ( E a ) and plant transpiration ( T r ) is important to understand response of ecosystem water balance to climate warming. A field experiment was conducted to investigate the effect of additional infrared radiation as a simulation of climate warming (W1: 130 W m −2 and W2: 150 W m −2 ) on ET , E a , T r , and soil moisture in an alpine meadow in the Qinghai-Tibet plateau (QTP). ET was calculated by using an energy balance model and a soil moisture correction function. E a in warm-rainy season was estimated by a multiple linear regression with latent heat, soil moisture in 0–10 cm layer and soil temperature in 20 cm depth as independent variables. T r was quantified as the difference between ET and E a . Results showed that annual ET increased by 92 mm and 89 mm, annual E a increased by 29.12 mm and 33.37 mm, and annual T r increased by 63.53 mm and 55.81 mm in W1 and W2 treatments, respectively. The results suggest that T r stimulation accounts for most of the ET change and is the major reason for the soil surface layer drying in alpine meadow ecosystem on the QTP. [ABSTRACT FROM AUTHOR]

Responses of ecosystem carbon (C) fluxes to human disturbance and climatic warming will affect terrestrial ecosystem C storage and feedback to climate change. We conducted a manipulative experiment to investigate the effects of warming and clipping on soil respiration (Rs), ecosystem respiration (ER), net ecosystem exchange (NEE) and gross ecosystem production (GEP) in an alpine meadow in a permafrost region during two hydrologically contrasting years (2012, with 29.9% higher precipitation than the long-term mean, and 2013, with 18.9% lower precipitation than the long-tem mean). Our results showed that GEP was higher than ER, leading to a net C sink (measured by NEE) over the two growing seasons. Warming significantly stimulated ecosystem C fluxes in 2012 but did not significantly affect these fluxes in 2013. On average, the warming-induced increase in GEP (1.49 µ mol m−2s−1) was higher than in ER (0.80 µ mol m−2s−1), resulting in an increase in NEE (0.70 µ mol m−2s−1). Clipping and its interaction with warming had no significant effects on C fluxes, whereas clipping significantly reduced aboveground biomass (AGB) by 51.5 g m−2 in 2013. These results suggest the response of C fluxes to warming and clipping depends on hydrological variations. In the wet year, the warming treatment caused a reduction in water, but increases in soil temperature and AGB contributed to the positive response of ecosystem C fluxes to warming. In the dry year, the reduction in soil moisture, caused by warming, and the reduction in AGB, caused by clipping, were compensated by higher soil temperatures in warmed plots. Our findings highlight the importance of changes in soil moisture in mediating the responses of ecosystem C fluxes to climate warming in an alpine meadow ecosystem. [ABSTRACT FROM AUTHOR]