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Fang Y.,CAS Chengdu Institute of Mountain Hazards and Environment

The three-rivers headwater region (THRHR) of Qinghai province, China plays a key role as source of fresh water and ecosystem services for central and eastern China. Global warming and human activities in the THRHR have threatened the ecosystem since the 1980s. Therefore, the Chinese government has included managing of the THRHR in the national strategy since 2003. The State Integrated Test and Demonstration Region of the THRHR highlights the connection with social engineering (focus on improving people's livelihood and well-being) in managing nature reserves. Based on this program, this perspective attempts a holistic analysis of the strategic role of the THRHR, requirements for change, indices of change, and approaches to change. Long-term success of managing nature reserves requires effective combination of ecological conservation, economic development, and social progress. Thus, the philosophy of social engineering should be employed as a strategy to manage the THRHR. © 2013 Royal Swedish Academy of Sciences. Source

Liu E.,University of Sichuan | He S.,CAS Chengdu Institute of Mountain Hazards and Environment
Engineering Geology

A series of laboratory tests were performed to assess the effects of confining pressure on the mechanical properties and fatigue damage evolution of sandstone samples subjected to cyclic loading. Six levels of confining pressure (2.0, 10.0, 20.0, 30.0, 40.0 and 50.0. MPa) were applied during axial cyclic loading at a 1.0. Hz frequency using a MTS-815 Rock and Concrete Test System. Results from the cyclic dynamic loading tests indicated that the level of confining pressure had a significant influence on the cyclic dynamic deformation and fatigue damage evolution of the sandstone samples tested. With increasing confining pressure, the axial strain at failure increased, as did the residual volumetric strain at the initiation of dilatancy. The residual axial strains of sandstone samples obtained at a confining stress state can be described as three deformational stages, namely, the initial phase, uniform velocity phase and accelerated phase. Both the residual strain method and the axial secant modulus method proposed here could be used to describe the initial fatigue damage and degradation process of sandstone samples subjected to fatigue loading under a confining stress state; however, the latter also considers the influence of stress level on fatigue damage evolution when fatigue loads are applied. At a constant confining pressure, the shear fracture plane can form under static and cyclic dynamic loading conditions, and the higher the confining pressure, the wider the shear fracture planes become under cyclic dynamic loadings. © 2011 Elsevier B.V. Source

Cui P.,CAS Chengdu Institute of Mountain Hazards and Environment | Lin Y.-M.,China Agricultural University | Chen C.,China Agricultural University
Ecological Engineering

Geo-hazards induced by earthquakes have caused ecosystem degradation and vegetation destruction. Little, however, is known about the consequences of geo-hazards due to a lack of research data. We have undertaken a study in the Wenchuan earthquake-affected area of China in order to identify and characterize vegetation destruction and its consequent environmental impact. The Wenchuan earthquake on 12th May, 2008 induced numerous geo-hazards (including rock avalanches, landslides, landslide-dammed lakes and debris flows) that caused vegetation destruction up to 1249.5km 2, of which shrub comprised the largest proportional area with 338.559km 2. The vegetation coverage decreased by 4.76% in 9 severely damaged cities and counties and by 12.37% in the Subao river, Beichuan county. Rock avalanches and landslides were the most common destructive types, resulting in 98.73% of all types of geo-hazards, whereas debris flows and landslide-dammed lakes accounted for 1.27%. Vegetation destruction was distributed along both sides of rivers causing erosion, formation of debris flows and landslides. Hydrologic progress was changed and hydrological adjusting function diminished due to vegetation deterioration resulting in bare rock (infiltration reduced, runoff increased and flow concentration expedited) and deposit region (infiltration increased and runoff reduced) in catchment. Soil erosion was intensified causing increased sediment transportation of rivers, decreased storage capacities of reservoirs downstream, a significantly increased area that has suffered severe erosion and aggravated magnitude and damage capability of debris flows and landslides. Ecosystem function declined and vegetation restoration and reconstruction was difficult due to co-degradation of vegetation-soil system in the earthquake-affected areas. Finally, we summarized the challenges faced in the future for vegetation restoration and reconstruction. © 2012 Elsevier B.V. Source

Jin X.,CAS Chengdu Institute of Mountain Hazards and Environment | Xu C.-Y.,University of Oslo | Zhang Q.,CAS Nanjing Institute of Geography and Limnology | Singh V.P.,Texas A&M University
Journal of Hydrology

Quantification of uncertainty of hydrological models has attracted much attention in hydrologic research in recent years. Many methods for quantification of uncertainty have been reported in the literature, of which GLUE and formal Bayesian method are the two most popular methods. There have been many discussions in the literature concerning differences between these two methods in theory (mathematics) and results, and this paper focuses on the computational efficiency and differences in their results, but not on philosophies and mathematical rigor that both methods rely on. By assessing parameter and modeling uncertainty of a simple conceptual water balance model (WASMOD) with the use of GLUE and formal Bayesian method, the paper evaluates differences in the results of the two methods and discusses the reasons for these differences. The main findings of the study are that: (1) the parameter posterior distributions generated by the Bayesian method are slightly less scattered than those by the GLUE method; (2) using a higher threshold value (>0.8) GLUE results in very similar estimates of parameter and model uncertainty as does the Bayesian method; and (3) GLUE is sensitive to the threshold value used to select behavioral parameter sets and lower threshold values resulting in a wider uncertainty interval of the posterior distribution of parameters, and a wider confidence interval of model uncertainty. More study is needed to generalize the findings of the present study. © 2010 Elsevier B.V. Source

Fang Y.-P.,CAS Chengdu Institute of Mountain Hazards and Environment
Journal of Mountain Science

The interaction among different livelihood capitals is a key to generate a deeper understanding of the livelihood sustainability. In this paper, we use net income per capita (economic capital), meat and milk production per capita (physical capital), and areas of fenced pasture, livestock shelter, grassland rodent control and planted grassland (physical capital) as proxy indicators of livelihood promotion, livelihood provision, and livelihood protection respectively. By developing a correlation model between pastoralists' livelihood protection and improvement, we found that (1) there is a statistically significant correlation between the pastoralists' livelihood protection and promotion; (2) based on the maximum effect of pastoralists' livelihood promotion and provision, there is a benchmark in the effect of the intervention intensity of livelihood capital (grassland resource protection) on livelihood improvement; (3) on basis of two indicators, i.e. net income per capita and meat production per capita, the reasonable scales of fenced pasture, livestock shelter and planted grassland are less than 843, 860 and 46 thousand hectares (hm2) per year respectively. With the marginal effect of livelihood protection, moderately decreased areas of fenced pasture and planted grassland, and increased area of livestock shelter is a critical to ensure pastoralist's livelihood sustainability. © 2013 Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg. Source

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