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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 northeastern Tibetan Plateau exhibits steep topography and strong internal or external dynamic geological effect and is frequently subjected to strong earthquakes and heavy rainfall. The geological evolution has resulted in a wide distribution of ancient landslides, which has become a hotspot for studying ancient landslide formation and reactivation. In recent decades, several ancient landslides on both banks of the Longwu River, Qinghai Province, China were reactivated, causing serious economic losses and casualties. This study conducted remote sensing interpretation and ground surveys on these ancient landslides. Totally 59 ancient landslides were identified, and the formation mechanism, evolution process, and resurrection mechanism of the Longwu Xishan No.2 ancient landslide were analyzed by means of a detailed field geological survey, drilling, and series of experimental tests such as the particle size distribution test, the X-ray diffraction test and the mechanical properties test. The results show that the formation of these ancient landslides is closely associated with the uplift of the Tibetan Plateau and the erosion of the Longwu River. Firstly, the intermittent uplift of the Tibetan Plateau lead to the diversion and downcutting of the Longwu River basin, which forms the alternate slope topography with steep and slow slopes, thereby providing favourable topography and slope structure conditions for the formation of landslides. Secondly, 34.5% clay-mineral content in the Neoproterozoic mudstone with 32.7% particle size less than 0.005 mm, and the corrosion and softening effects of the Neogene mudstone with high clay mineral content under the erosion of water provides favourable material conditions for the formation of landslides. Thirdly, rainfall and human activities are the primary triggering factors for the revival of this ancient landslide group. It is revealed that the evolution process of the ancient landslides on both banks of the Longwu River can be divided into five stages namely tectonic rapid uplift slope formation, river erosion creep-sliding deformation, slope instability critical status, landslide failure-movement-accumulation, and slope reactivation under rainfall erosion and engineering excavation. [ABSTRACT FROM AUTHOR]

The high sensitivity of the Tibetan Plateau (TP) to global warming is ascribed not only to its high altitude and low temperature but also to the change in the components of water cycling, such as glaciers’ retreat, permafrost degradation, and lakes’ shrinkage or expansion. Among the components, change in lakes attracts more attention as lakes are crucial for local water management and are easier to monitor. But, how water cycling components respond to global change remains unclear, although they are crucial in understanding the regional environmental change. Lakes, glaciers, and permafrost data derived from meteorological records and remote sensing images were used to detect the change of the water environment on the TP from 1971 to 2013. The climate on TP changed toward a warm-humid condition in the last four decades. Three-quarters of the lakes were significantly expanded over the TP, and the summed area of all the lakes increased by 6061 km2 from 1975 to 2010. Panel regression showed that annual average air temperature (T), annual precipitation (P), and reference crop evapotranspiration (ETo) regulate the change in lake surface area (LSA) on the entire TP. The change in LSA is more related to the change in P than in the other two factors, even in the catchment where lakes are recharged by water from glacier melting and permafrost degradation, especially in extremely arid and arid climate zones. Elevation and size affected the sensitivity of lakes to climate change with lakes in a high-elevation area more sensitive to T and small lakes more sensitive to T, P, and ETo. Warming-induced glacier’s retreat led to the significant lake expansion, while permafrost degradation might be responsible for the lake shrinkage in the seasonally frozen ground area due to the related cryogenic waterproof layer downward. Our results about the responses of lakes to climate change in different catchments were in accordance with the findings of previous studies about several typical lakes, which implied that overall response of all the lakes to climate change could be obtained by examining several typical lakes in the catchment level. [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]

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]

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]

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]