Impacts of the Wenchuan Earthquake on the giant panda nature reserves in China

The Wenchuan Earthquake that occurred in May of 2008 caused damages to large areas of Sichuan, Gansu, and Shaanxi provinces in China. Reports from local governments and related management agencies show that the giant panda nature reserves in the earthquake-hit areas were heavily damaged. Our estimates in this paper of the impacts of the earthquake on the giant panda in the earthquake-hit areas were made based on the interpretation of remote sensing images and information collected by field survey. A rapid assessment method was designed to estimate the damages of the earthquake on giant panda habitats. By using visual interpretation methods, we decoded the remote sensing images of the disaster area in the 49 giant panda nature reserves. Research results showed that the Wenchuan Earthquake and the succeeding secondary geological disasters caused great damages to the giant panda nature reserves and disturbed the normal life of the giant pandas there (e.g., landscape fragmentation increased significantly). Undoubtedly, the life of the giant pandas there was affected. However, although the earthquake caused certain impacts on the giant pandas, it did not really threat their survival. Even so, we still strongly advocate for protection of the giant pandas, and have prioritized a couple of measures to be taken to restore the giant panda nature reserves in the earthquake-hit areas.     

Evaluating conservation effectiveness of nature reserves established for surrogate species: Case of a giant panda nature reserve in Qinling Mountains, China

Many nature reserves are established to protect the habitat needs of particular endangered species of interest but their effec-tiveness for protecting other species is questionable.In this study,this effectiveness was evaluated in a nature reserve network located in the Qinling Mountains,Shaanxi Province,China.The network of reserves was established mainly for the conservation of the giant panda,a species considered as a surrogate for the conservation of many other endangered species in the region.The habitat suitability of nine protected species,including the giant panda,was modeled by using Maximum Entropy（MAXENT） and their spatial congruence was analyzed.Habitat suitability of these species was also overlapped with nature reserve boundaries and their management zones（i.e.,core,buffer and experimental zones）.Results show that in general the habitat of the giant panda constitutes a reasonable surrogate of the habitat of other protected species,and giant panda reserves protect a relatively high proportion of the habitat of other protected species.Therefore,giant panda habitat conservation also allows the conservation of the habitat of other protected species in the region.However,a large area of suitable habitat was excluded from the nature reserve network.In addition,four species exhibited a low proportion of highly suitable habitat inside the core zones of nature reserves.It suggests that a high proportion of suitable habitat of protected species not targeted for conservation is located in the experimental and buffer zones,thus,is being affected by human activities.To increase their conservation effectiveness,nature reserves and their management zones need to be re-examined in order to include suitable habitat of more endangered species.The procedures described in this study can be easily implemented for the conservation of many endangered species not only in China but in many other parts of the world.     

Field investigations and numerical modeling of a giant landslide in the region of Eastern Himalayan Syntaxis:Jiaobunong landslide

Eastern Himalayan Syntaxis (EHS) is a tectonically active region that undergoes continuous geomorphic changes.Large landslides are predominant in this region.A ...     

Nature and timing of a prehistoric giant landslide on the eastern margin of the Tibetan Plateau

Studying the characteristics of a prehistoric giant landslide and ascertaining its relationship with palaeo-seismic events could provide useful information on the role of regional tectonic activities in hillslope evolution. Here, a giant palaeoseismic landslide(GPSL), namely, the Luanshibao(LSB) landslide, located on the eastern margin of the Qinghai-Tibet Plateau, was investigated to ascertain its characteristics and occurrence age. The relationship between occurrence age and palaeoseismic episodes was also discussed by using 14 C dating on the adjacent active faults, including the regional Yidun-Litang-Dewu(YD-LT-DW) fault zone,which crossed the LSB landslide. The dating of multiple samples acquired from palaeo-seismic trenches revealed that at least 5 palaeo-seismic episodes had occurred in the vicinity of the LSB landslide over the last 5000 years. The occurrence age of the LSB landslide(3635 ± 387 a BP) coincides with palaeo-seismic episode I, and the LSB landslide is convincingly inferred to have been triggered during episode I, which reached a seismic intensity(Chinese scale) of at least degree VII near the LSB landslide during failure. The timing of a second reactivation phase coincides with palaeo-seismic episode IV,which occurred at 2100-2200 a BP. The study could provide reference for studying the regional palaeoseismic activities and palaeo landslide evolution near the Litang area.     

Numerical simulation of a high-speed landslide in Chenjiaba,Beichuan, China

High-speed landslide is a catastrophic geological disaster in the mountainous area of southwest China. To predict the movement process of landslide reactivation in Chenjiaba town, Beichuan county, Sichuan province, China, we simulated the movement process of two landslide failures in Chenjiaba via rapid mass movement simulation and unmanned aerial vehicle images(UAV), and obtained the movement characteristic parameters of the landslides. According to a back analysis, the most remarkable fitting rheological parameters were friction coefficient(μ=0.18) and turbulence(). The parameter of landslide pressure was applied as the zoning index of landslide hazard to obtain the influence zone and hazard zoning map of the Chenjiaba landslide. Results show that the Duba River was blocked quickly with a landslide accumulation at the maximum height of 44.14 mwhen the Chenjiaba deposits lost stability. The hazard zoning map indicated that the landslide hazard degree is positively correlated with the slope.This landslide assessment is a quantitative hazard assessment method based on a landslide movement process and is suitable for high-speed landslide. Such method can provide a scientific basis for urban construction and planning in the landslide hazard area to avoid hazards effectively.     

Effect of grassland mosaic structure and dynamism on the reproductive habitat suitability for Alectoris graeca in central Apennines

Over the last several decades, the Mediterranean region has been subjected to mountain abandonment and farming cessation, leading to changes in vegetation and coenological features of grasslands, contextually to the strong decline of the rock partridge(Alectoris graeca). Our hypothesis was that the ongoing dynamic processes leading to the compositional changes of grasslands in central Apennines affect the habitat suitability for the singing male(territorial male defending its reproductive site).In 2015, we defined the presence/absence of spring territorial singing males in seven sites(1,250-2,400 m a.s.l.), by the census in 74 playback stations,distributed along 15 transects. We characterized the topography and the vegetation mosaic of such sites according to the collected topographic and vegetation cover data in 59 randomly selected plots(100 m × 100 m) along the transects. To understand the relations among the environmental variables and the effect of the composition and dynamism of the vegetation mosaics on the presence/absence of the singing male,we used principal components analysis and generalized linear mixed-effect modelling. Our results emphasized the marked overlap between the general environmental conditions, which proved to define the habitat suitability for A. graeca, and the characteristics of the site chosen by the singing male for starting the reproductive activities. Moreover, we found that the site suitability for the singing male decreases when the vegetation recovery processes are ongoing, because of the spread of coarse tall grassesdominated communities and/or grassland types with dense turf. Tall grass-dominated communities and thick-turf grasslands exert their negative effect decreasing the habitat suitability for the singing male starting from low cover values. Therefore, it is conceivable that singing male's suitable habitat will be dramatically restricted to the steepest south-facing slopes, where topographic and soil conditions do not allow the spread of grasslands with dense turf and of invasive/dominant tall grasses, increasing the threat to the species due to the effect of climate change on the vegetation features.     

Spatial distribution and sources identification of polycyclic aromatic hydrocarbons in Wolong Lake,Northeast China

The aquatic ecosystem maybe significantly affected by polycyclic aromatic hydrocarbons(PAHs) released from fresh water sediments. In order to protect biodiversity, the spatial distribution and sources of PAHs in the sediment of Wolong Lake in Northeast China were studied. A total of 17 surface sediment samples were collected and 12 PAHs were analyzed. The results were as follows. The concentration of total PAHs(TPAHs) ranged between 1412.9 μg/kg and 3948.3 μg/kg(dry weight). Indeno [1, 2, 3-c, d] pyrene was the dominant contaminant which accounted for 87%–98% of TPAHs. Diagnostic ratios of PAHs and principal component analysis showed that biomass combustion and vehicle emissions were likely to be the dominant sources of PAHs in the sediment. PAHs can be considered safe in the context of environmental and human health protection, based on the overall toxicity. Individual PAHs were positively correlated with total organic carbons. These results will be helpful to control PAHs and protect the aquatic ecosystem in the lake.     

A comprehensive evaluation of tourism climate suitability in Qinghai Province, China

Qinghai Province is an important component of the Qinghai-Tibet Plateau in China. Scientific evaluation of the suitability of Qinghai’s climate for tourism can contribute to overcoming obstacles posed by climate on sustainable tourism development in Qinghai Province, including disparities between the low and high seasons, high altitude health concerns, and weather events. A tourism climate suitability evaluation model of the Qinghai-Tibet Plateau is constructed (Tourism Climate Suitability Index, or TCSI), and tourism climate suitability is comprehensively evaluated for Qinghai Province from climate data from 1960 to 2009. Results show that: (I) There is clear distributional characteristics of spatial-temporal variability of TCSI values in Qinghai Province. (II) Tourism climate suitability in Qinghai Province has significant seasonal and regional differences. The year is divided into a very suitable period (July and August), suitable tourism periods (from April and October), less suitable periods (From Nov to Mar). June to August is the most suitable tourism period in Qinghai. Qinghai Province is divided into five levels of tourism climate suitability: most suitable regions, very suitable regions, suitable regions, less suitable regions, and unsuitable region. (III) The key factor which influences regional differences in tourism climatic suitability is atmospheric oxygen. And the key factors which chiefly influence seasonal differences of tourism climate suitability are temperature and humidity, the wind chill factor, and barrier weather.     

Impact of the Wenchuan Earthquake on tourism in Sichuan, China

An intensive earthquake, the Wenchuan Earthquake of 8.0 on the Richter scale, struck western Sichuan, China on May 12, 2008. The earthquake has tremendously affected all industries in the quake-hit areas, with no exception ：of the local tourism. The study of the effect of the earthquake on tourism enriches the theory of tourism, and more importantly, it well serves as the foundation for policy making. The objective of this study is to outline for readers the empirical findings on the various ways that the earthquake affected the operations and viability of tourism in the quake-hit areas. This paper is mainly divided into 3 parts. The first part is to discuss the importance of tourism in the quake-hit areas. The second is to analyze the influencing factors of tourism. The third is to assess the impact of the earthquake on tourism in Sichuan in different seasons.     

On the initiation,movement and deposition of a large landslide in Maoxian County,China

At 5 am 24 th June 2017, a catastrophic landslide hit Xinmo Village, Maoxian County, Sichuan Province, China. The slide mass rushed down from an altitude of 3400 m and traveled 2700 m in a high velocity. The 13 million m~3 deposition buried the whole village and caused about 100 deaths. The source area of the landslide is located in a high steep slope, average slope angle is 40o and maximal angle is 65o. The strata are interbedded Triassic Zagunao Formation metamorphic sandstone and slate with the dip slope angle of 45°. Based on high-resolution satellite remote sensing image, UAV image, DEM data, and field investigation, failure mechanism, travel features, and deposit characteristics were analyzed. The results showed that this landslide was influenced by Songpinggou Fault zone. According to the topography before the failure, the landslide is located in the back scarp of an antecedent landslide induced by Diexi Earthquake in 1933. The bedding slope provided potential rupture surface. Historical seismic activities and long-term gravitational deformation caused rock mass accumulated damages. Weathering and precipitation weakened the rock mass and finally induced shearing and tension failure. A huge block detached from the top rock slope, pushed the past landslide deposits in the middle part, rushed out of the slope bottom in a high velocity and buried the Xinmo Village. The rapid movement entrained and brought the soil into the Songping Gully which recoiled with and bounced back from the opposite mountain.     

Ecological suitability assessment and introduction experiment on Rosa damascena trigintipetala in Sichuan Province,China

This study comprehensively considered the climate, soil, terrain, and land-use type conditions suitable for Rosa damascena trigintipetala and further established an ecological suitability evaluation model of R. damascena trigintipetala in Sichuan Province, China, based on geographic information systems(GIS) and Agro-Ecological Zone(AEZ)models; then we assessed the different ecological suitability grades for this species in Sichuan Province of China and summarized the suitable land areas and spatial distribution pattern for R. damascena trigintipetala. The results show that the suitable areas(which contain highly suitable, generally suitable, and critically suitable areas) for R. damascena trigintipetala are 307.268×104 hm2, which accounts for 6.34% of the total provincial area. Results also indicate that shrub land and open forest land are the major land-use types suitable for R. damascena trigintipetala, with the suitable areas of 303.162×104hm2(6.25% of the total provincial area). An introduction test was conducted in one of the suitable areas, Xichang City, which demonstrated that R.damascena trigintipetala grows well at theexperimental sites. The quality of rose oil extracted from R. damascena trigintipetala planted in Xichang meets the Bulgaria Rose Oil Standard, thus verifying the accuracy and reliability of the ecological suitability assessment results.     

Modeling habitat suitability of range plant species using random forest method in arid mountainous rangelands

Mountainous rangelands play a pivotal role in providing forage resources for livestock, particularly in summer, and maintaining ecological balance. This study aimed to identify environmental variables affecting range plant species distribution, ecological analysis of the relationship between these variables and the distribution of plants, and to model and map the plant habitats suitability by the Random Forest Method(RFM) in rangelands of the Taftan Mountain, Sistan and Baluchestan Province, southeastern Iran. In order to determine the environmental variables and estimate the potential distribution of plant species, the presence points of plants were recorded by using systematic random sampling method(90 points of presence) and soils were sampled in 5 habitats by random method in 0–30 and 30–60 cm depths. The layers of environmental variables were prepared using the Kriging interpolation method and Geographic Information System facilities. The distribution of the plant habitats was finally modelled and mapped by the RFM. Continuous maps of the habitat suitability were converted to binary maps using Youden Index(?) in order to evaluate the accuracy of the RFM in estimation of the distribution of species potentialhabitat. Based on the values of the area under curve(AUC) statistics, accuracy of predictive models of all habitats was in good level. Investigating the agreement between the predicted map, generated by each model, and actual maps, generated from fieldmeasured data, of the plant habitats, was at a high level for all habitats, except for Amygdalus scoparia habitat. This study concluded that the RFM is a robust model to analyze the relationships between the distribution of plant species and environmental variables as well as to prepare potential distribution maps of plant habitats that are of higher priority for conservation on the local scale in arid mountainous rangelands.     

Characteristics and triggering mechanism of Xinmo landslide on 24 June 2017 in Sichuan,China

At 5: 39 AM on 24 June 2017, a huge landslide-debris avalanche occurred on Fugui Mountain at Xinmo village, Diexi town, Maoxian county, Sichuan province, China. The debris blocked the Songpinggou River for about 2 km, resulting in a heavy loss of both human lives and properties (10 deaths, 3 injuries, 73 missing, and 103 houses completely destroyed). The objectives of this paper are to understand the overall process and triggering factors of this landslide and to explore the affecting factors for its long term evolution before failure. Post event surveys were carried out the day after the landslide occurrence. Information was gathered from literature and on-site investigation and measurement. Topography, landforms, lithology, geological setting, earthquake history, meteorological and hydrological data of the area were analysed. Aerial photographs and other remote sensing information were used for evaluation and discussion. Eye witnesses also provided a lot of helpful information for us to understand the process of initiation, development and deposition. The depositional characteristics of the moving material as well as the traces of the movement, the structural features of the main scarp and the seismic waves induced by the slide are presented and discussed in detail in this paper. The results show that the mechanism of the landslide is a sudden rupture of the main block caused by the instability of a secondary block at a higher position. After the initiation, the failed rock mass at higher position overloaded the main block at the lower elevation and collapsed in tandem. Fragmentation of the rock mass occurred later, thus forming a debris avalanche with high mobility. This landslide case indicates that such seismic events could influence geological hazards for over 80 years and this study provides reference to the long term susceptibility and risk assessment of secondary geological hazards from earthquake.     

基于信息量模型的中国滑坡灾害风险区划研究

基于信息论发展起来的信息量模型是进行区域滑坡灾害风险评估的一种有效方法。GIS技术为滑坡灾害在不同模型条件下的风险评估提供了有效地技术支持。经过研究，开发出了基于MapGIS软件平台的滑坡灾害风险分析系统。在该系统支持下．采用信息量模型对中国范围内的滑坡灾害进行危险性分析。进而进行区域社会经济易损性分析。并在此基础上进行最终的滑坡灾害风险评估。     

Evaluation of the production-living-ecology space function suitability of Pingshan County in the Taihang mountainous area,China

A rational utilization of land is a matter of importance in sustainable development of mountainous area. The land function in mountainous areas has a close connection with space structure of ecology, production and living. To promote a harmonious development of the relationship between people and nature in mountainous areas, it is necessary to coordinate their relationships of space functions. Suitability evaluation of basic unit function associated with multi-scale space analysis is a prerequisite to a reasonable optimization of land function structure. In this study, an optimized evaluation index system of combination functions was introduced into the assessment of ecological spatial functional suitability in ecological fragile regions by adding three indicators, namely, soil erosion sensitivity, landscape ecological risk and ecological sensitivity. The principle of "taking high"(referred to a function with high suitability to be regarded as the main function of an evaluation unit) and ecological priority(referred to the case, supposing the suitability of a unit's three functions is consistent, the main function is determined to be the ecological function) were used to determine the main function of an evaluation unit. Pingshan County, China, located at the eastern foot of the Taihang Mountain, was targeted in this case study. The production-livingecology space(PLES) function in Pingshan was identified by applying our improved valuation indexes. Further, the functional suitability distribution of the combination of elements was obtained by using overlapping comprehensive analysis method, considering the tradeoff of the functional suitability of combination elements. The regions suitable for production/living were distributed in relatively flat piedmont plains, whereas the regions suitable for ecology were distributed in the mountain areas of middle and low altitudes. Therefore, to maintain a sustainable development in mountainous areas, an improved scheme of development for Pingshan should be to delineate ecologically fragile areas, to build ecological industrial parks near existing scenic spots, to protect basic agricultural production areas, and to increase investment in science and technology, including reasonable ecological compensation. This study can provide reference for the planning of sustainable development in the Taihang Mountain area and similar regions.     

Long-term activity of earthquake-induced landslides: A case study from Qionghai Lake Basin,Southwest of China

Earthquake-triggered landslides are a major geological hazard in the eastern Tibetan Plateau, and have prolonged impact on earth surface processes and fluvial system. To determine how long co-seismic landslides affect basins, a massive number of landslides existing in Qionghai Lake Basin were investigated for landslide distribution characteristics and geomorphological evidences, with further comparison and analysis using historic seismic analog method. The landslides found in Qionghai Lake Basin showed clear features of seismic triggering with strongly controlled by Zemuhe fault. These landslides are still active at present. Some new slides generally occur in ancient slope failure zones causing serious secondary hazards in recent years. In this study we strengthen the idea that the landslides triggered by the 185o Xichang earthquake （Ms7.5） have long term activity and prolonged impact on the mountain disasters with a period of more than 16o years. Our results support growing evidence that coseismic landslides have a prolonged effect on secondary disasters in a basin, and invite more careful consideration of the relationship between current basin condition and landslide history for a longer period.     

Modeling a habitat suitability index for the eastern fall cohort of Ommastrephes bartramii in the central North Pacific Ocean

The eastern fall cohort of the neon flying squid, Ommastrephes bartramii, has been commercially exploited by the Chinese squid jigging fleet in the central North Pacific Ocean since the late 1990s. To understand and identify their optimal habitat, we have developed a habitat suitability index (HSI) model using two potential important environmental variables - sea surface temperature (SST) and sea surface height anomaly (SSHA) - and fishery data from the main fishing ground (165°-180°E) during June and July of 1999-2003. A geometric mean model (GMM), minimum model (MM) and arithmetic weighted model (AWM) with different weights were compared and the best HSI model was selected using Akaike’s information criterion (AIC). The performance of the developed HSI model was evaluated using fishery data for 2004. This study suggests that the highest catch per unit effort (CPUE) and fishing effort are closely related to SST and SSHA. The best SST- and SSHA-based suitability index (SI) regression models were SISST-based = 0.7SIeffort-SST + 0.3 SICPUE-SST, and SISSHA-based = 0.5SIeffort-SSHA + 0.5SICPUE-SSHA, respectively, showing that fishing effort is more important than CPUE in the estimation of SI. The best HSI model was the AWM, defined as HSI=0.3SISST-based+ 0.7SISSHA-based, indicating that SSHA is more important than SST in estimating the HSI of squid. In 2004, monthly HSI values greater than 0.6 coincided with the distribution of productive fishing ground and high CPUE in June and July, suggesting that the models perform well. The proposed model provides an important tool in our efforts to develop forecasting capacity of squid spatial dynamics.     

Deformation characteristics and thresholds of the Tanjiawan landslide in the Three Gorges Reservoir Area,China

Since the first impoundment of the Three Gorges Reservoir(TGR) in China in 2003, more than 5000 landslides including potential landslides were identified. In this paper, a deep-seated active landslide in TGR area was analyzed. Fourteen years’ monitoring data and field investigations from 2006 to 2020 were used to analyze the deformation characteristics, influencing factors, and meteohydrological thresholds. The landslide showed a none-overall periodic movement pattern featuring acceleration duri...     

Numerical modeling and dynamic analysis of the 2017 Xinmo landslide in Maoxian County,China

A catastrophic landslide occurred at Xinmo village in Maoxian County, Sichuan Province,China, on June 24, 2017. A 2.87×106 m3 rock mass collapsed and entrained the surface soil layer along the landslide path. Eighty-three people were killed or went missing and more than 103 houses were destroyed. In this paper, the geological conditions of the landslide are analyzed via field investigation and high-resolution imagery. The dynamic process and runout characteristics of the landslide are numerically analyzed using a depth-integrated continuum method and Mac Cormack-TVD finite difference algorithm.Computational results show that the evaluated area of the danger zone matchs well with the results of field investigation. It is worth noting that soil sprayed by the high-speed blast needs to be taken into account for such kind of large high-locality landslide. The maximum velocity is about 55 m/s, which is consistent with most cases. In addition, the potential danger zone of an unstable block is evaluated. The potential risk area evaluated by the efficient depthintegrated continuum method could play a significant role in disaster prevention and secondary hazard avoidance during rescue operations.     

The formation of the Wulipo landslide and the resulting debris flow in Dujiangyan City,China

The Wulipo landslide, triggered by heavy rainfall on July 10, 2013, transformed into debris flow,resulted in the destruction of 12 houses, 44 deaths, and 117 missing. Our systematic investigation has led to the following results and to a new understanding about the formation and evolution process of this hazard. The fundamental factors of the formation of the landslide are a high-steep free surface at the front of the slide mass and the sandstone-mudstone mixed stratum structure of the slope. The inducing factor of the landslide is hydrostatic and hydrodynamic pressure change caused by heavy continuous rainfall. The geological mechanical model of the landslide can be summarized as "instability-translational slide-tension fracture-collapse" and the formation mechanism as "translational landslide induced by heavy rainfall". The total volume of the landslide is 124.6×104 m3, and 16.3% of the sliding mass was dropped down from the cliff and transformed into debris flow during the sliding process, which enlarged 46.7% of the original sliding deposit area. The final accumulation area is found to be 9.2×104 m2. The hazard is a typical example of a disaster chain involving landslide and its induced debris flow. The concealment and disaster chain effect is the main reason for the heavy damage. In future risk assessment, it is suggested to enhance the research onpotential landslide identification for weakly intercalated slopes. By considering the influence of the behaviors of landslide-induced debris flow, the disaster area could be determined more reasonably.