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过刊目录

  • 2021年, 18卷, 第08期
    刊出日期：2024-06-19
      
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  • A history of tourism at the Mer de Glace: Adaptations of glacier tourism to glacier fluctuations since 1741
    Emmanuel SALIM, Laura MABBOUX, Ludovic RAVANEL, Philip DELINE, Christophe GAUCHON
    2021, 18(08): 1977-1994.
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    Climate change induces profound changes in mountain territories that affect the activities pursued there. Tourism is one activity that is strongly impacted by these changes. Most research on tourism in mountain regions has focused on winter sports tourism, but glacier tourism, a summer activity, is also severely affected by climate change-induced phenomena, including glacier retreat and other geomorphological processes. Given that Alpine glacier tourism has been pursued since the 18 th century and glaciers have been changing throughout this period, this article aims to examine the adaptations implemented by glacier tourism operators since the activity's beginnings. Through analysis of historical documents, glaciological surveys and semi-structured interviews, this paper reveals how tourism activities around the Mer de Glace(the largest French glacier) have been impacted by glacier fluctuations since the first visit to the area in 1741. The study reveals that these developments have mainly been driven by glacier retreat and associated paraglacial dynamics. More recently, the shortening of the period of snow cover on the glacier has also impacted tourism activities. Most of the adaptation strategies implemented by tourism operators during the period in question are found to be reactive, consisting in the installation of safety equipment, the renovation of access points or the building of new structures to allow tourist activities to continue despite the consequences of glacier retreat. Other strategies, such as the adoption of new activities by workers previously specialised in another, are identified that could be considered transformative strategies, although these were only adopted by workers when their activity was no longer feasible. The analysis of materials from 1741 to the present also reveals that the recent impacts of climate change on glacier tourism are much more significant and diverse than those produced by past fluctuations. Therefore, it is important that stakeholders take suitable measures to ensure the sustainable future of the Mer de Glace and other glacier tourism destinations.
  • Multi-model assessment of glacio-hydrological changes in central Karakoram, Pakistan
    Javed HASSAN, CHEN Xiao-qing, Rijan Bhakta KAYASTHA, NIE Yong
    2021, 18(08): 1995-2011.
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    The multi-model assessment of glaciohydrological regimes can enhance our understanding of glacier response to climate change. This improved knowledge can uplift our computing abilities to estimate the contributing components of the river discharge. This study examined and compared the hydrological responses in the glacier-dominated Shigar River basin(SRB) under various climatic scenarios using a semi-distributed Modified Positive Degree Day Model(MPDDM) and a distributed Glacio-hydrological Degree-day Model(GDM). Both glacio-hydrological models were calibrated and validated against the observed hydro-meteorological data from 1988-1992 and 1993-1997. Temperature and precipitation data from Shigar and Skardu meteorological stations were used along with field estimated degree-day factor, temperature, and precipitation gradients. The results from both models indicate that the snow and ice melt are vital contributors to sustain river flow in the catchment. However, MPDDM estimated 68% of rain and baseflow contribution to annual river runoff despite low precipitation during the summer monsoon, while GDM estimated 14% rain and baseflow contribution. Likewise, MPDDM calculated 32%, and GDM generated 86% of the annual river runoff from snow and ice melt. MPDDM simulated river discharge with 0.86 and 0.78 NSE for calibration and validation, respectively. Similarly, GDM simulated river discharge with improved accuracy of 0.87 for calibration and 0.84 NSE for the validation period. The snow and ice melt is significant in sustaining river flow in the SRB, and substantial changes in melt characteristics of snow and ice are expected to have severe consequences on seasonal water availability. Based on the sensitivity analysis, both models' outputs are highly sensitive to the variation in temperature. Furthermore, compared to MPDDM, GDM simulated considerable variation in the river discharge in climate scenarios, RCP4.5 and 8.5, mainly due to the higher sensitivity of GDM model outputs to temperature change. The integration of an updated melt module and two reservoir baseflow module in GDM is anticipated to advance the representation of hydrological components, unlike one reservoir baseflow module used separately in MPDDM. The restructured melt and baseflow modules in GDM have fundamentally enriched our perception of glacio-hydrological dynamics in the catchment.
  • OSL chronology of a Palaeolithic site in a humid subtropical mountainous area of southeast China
    JIN Jian-hui, WANG Xiao-yang, ZHOU Zhen-yu, HUANG Yun-ming, FAN Xue-chun, ZUO Xin-xin, LI Zhi-zhong, LING Zhi-yong, REN Yong-qing, LI Shu-tong
    2021, 18(08): 2012-2023.
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    The timing of Palaeolithic human activities in South China is still controversial because of the lack of a reliable chronology of archaeological sites. The Longdengshan Palaeolithic site(LPS), located close to the Wuyi Mountain of South China, represents the first discovered and scientifically excavated Middle Palaeolithic site in the Fujian Province. This site is of considerable significance for studying the diffusion and cultural connotation of early Homo sapiens in southern China. In this study, we present optically stimulated luminescence(OSL) ages obtained from medium-grained quartz collected at the LPS. The single-aliquot regenerative-dose measurements of red soil deposits collected at the same site yielded internally and stratigraphically consistent ages and similar errors, indicating a potential ability of the technique, and also reflecting the influence of various sedimentary facies on the test results. Our results indicate that the 38-63 μm quartz grains were generally partially-bleached and had large values of over-dispersion in the palaeo-reticulated laterites of west Fujian. Some samples yielded unsatisfactory results, suggesting that the degree of bleaching of diluvial and alluvial deposits should be properly assessed before dating. We did not detect any enrichment/depletion of U, Th and radioactive disequilibrium. The effect of chemical weathering on the dose rate estimation was negligible. Therefore, we used a central age model and the maximum age model to calculate the age of two samples, respectively, and the minimum age model to calculate the ages of the rest of the samples. The OSL ages of the samples ranged from 27.09 ± 2.30 ka to 54.65 ± 7.39 ka for the 38-63 μm quartz size fraction, and roughly corresponded to the Marine Isotope Stage 3. In addition, three ages out of five are based on the calculation of minimum ages in this research, which needs to be further verified by other dating methods.
  • Potential distribution of a montane rodent(Cricetidae, Handleyomys chapmani) through time in Mexico: the importance of occurrence data
    CANO Ivonne, GUEVARA Lázaro
    2021, 18(08): 2024-2033.
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    Ecological Niche Modeling uses the geographic coordinates of species presence records as the primary input to estimate potential geographic distributions. It is little known whether carrying out rigorous data pre-processing is necessary before building niche models to be transferred to different time period. Here we compared the current, past, and future potential distributions projected by niche models built from two different databases, an openaccess database and a database compiled ad hoc, for Handleyomys chapmani, a rodent closely associated with montane cloud forests in Mexico. The models predicted different spatial patterns of climatic suitability for the three periods examined. Based on our current knowledge of cloud forest species in Mexico, the distributions predicted by the model built from the ad hoc database are more ecologically realistic than those obtained from the open-access database. The models built using the open-access database were particularly inaccurate at the limits of the geographic range, predicting larger, more diffuse distributions for the three periods. We conclude that pre-processing occurrence data is crucial for mountain species, as the number of localities and even minor inaccuracies in the geographic coordinates can translate into very different climatic conditions due to abrupt altitudinal changes. Finally, the predicted shifts in the potential distribution of H. chapmani over time indicate that this species is highly susceptible to climate change.
  • Variations in aeolian landform patterns in the Gonghe Basin over the last 30 years
    QI Yu-han, PAN Mei-hui, HAO Ze-wen, YANG An-na, XUE Wen-xuan
    2021, 18(08): 2034-2047.
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    Wind erosion, or the transportation and deposition of sand into desert dunes and aeolian loess, is one of the most important aeolian activities. The progression of aeolian landforms expands arid and barren landscapes, leading to the degradation of adjacent areas. The Gonghe Basin, as a typical plateau with abundant sand sources, is highly sensitive to changes in the local climate conditions. In order to quantify the spatial-temporal variations in the aeolian landforms in the Gonghe Basin, we conducted field surveys and also analyzed twelve remote sensing(Landsat5 TM and Landsat8 OLI) images that sample the Gonghe Basin from 1989 to 2019. In the Gonghe Basin, we identified aeolian landforms such as climbing dunes on the windward slopes of the foothills, checkerboard dunes in the southeastern part of the basin, flat dunes, parabolic dunes and crescent dunes on the east and west sides of Longyangxia Reservoir, shrubby sandbanks on the valley slope in Shazhuyu, Tanggemu, and Indel, and sandy thickets at the bottom of the valley near the Dalian Sea, the Longyangxia Reservoir, and the tributaries of the Yellow River. From 1989 to 2005, the area of theaeolian regions expanded by 816.7 km~2, with an annual conversion rate of 0.05%. From 2015 to 2019, the area of the aeolian regions shrunk by 2411.9 km~2, with an annual conversion rate of-0.15%.The number and size of the fixed and semi-fixed dunes(e.g. the shrubby sandbanks on the valley slope and the sandy thickets at the bottom of the valley) were more stable than those of the mobile dunes(e.g. the checkerboard dunes, the flat dunes, the crescent dunes, the parabolic dunes, and the climbing dunes). The fixed and semi-fixed dunes were arranged in an irregular ring shape, and the location of the center of gravity of this ring did not change significantly from 1989 to 2019; in this time, the mobile dunes migrated to the northwest.
  • Quartz grain surface microtextural evidence for provenance of the Quaternary aggradation red earth deposit, southern China
    FAN Qing-bin, LIAO Jie, Li Yan, YE Wei, WANG Tao, FENG Xiao
    2021, 18(08): 2048-2060.
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    The Quaternary aggradation red earth(QARE) deposit in the middle reaches of the Yangtze River(MRYR) in southern China provides important evidence for understanding the paleoenvironment. However, its provenance remains controversial. In this study, the surface microtextures of grains from the QARE were observed, and compared with those of grains from the loess deposit on the Loess Plateau in northern China. The results show that the surface microtextures and morphologies of the quartz grains in the QARE are distinctly different from those in the northern loess, indicating that the deposits in the two regions have different provenances. The Gobi and deserts in inland northwestern China are not considered as the primary provenance for the QARE in southern China. It is suggested that the large areas of dry and bare river and lake beds and floodplains in the MRYR, which became exposed during glacial periods, provided the dominant source for materials in the QARE. We suggest that against the background of the middle-Pleistocene climate transition(MPT), regional aridification and a strengthened east Asian winter monsoon(driven by global cooling and the rapid uplift of the Tibetan Plateau) were primary drivers for the initiation of the QARE deposit in the MRYR region in southern China. The development of large areas of aeolian red earth deposit is direct evidence of environmental deterioration in the MRYR, indicating a cold and dry environment with frequent aeolian activity, in an area that now experiences a warm and humid subtropical monsoon climate. The results are also evidence of a regional response in the mid-subtropics of southern China to the MPT global cooling event around 1.2 Ma.
  • Hydrogeochemical and isotopic characteristics of spring water in the Yarlung Zangbo River Basin, Qinghai-Tibet Plateau, Southwest China
    LI Ying-zhi, GAO Zong-jun, LIU Jiu-tan, WANG Min, HAN Cong
    2021, 18(08): 2061-2078.
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    The Yarlung Zangbo River Basin(YZRB) is situated in the southern part of the Tibetan Plateau and remains in a mostly natural state. To understand the chemical characteristics of spring water and its controlling factors in the YZRB, 68 sets of spring water samples were analyzed using hydrochemical and isotopic techniques. The spring water was found to be slightly alkaline with total dissolved solids(TDS) below 1000 mg L-1. Major ions were Mg2+, Ca2+, SO42-, and HCO3-. The spring water types in this basin were determined to be HCO3-Ca·Mg and SO4·Cl-Ca·Mg. Ion exchange and dissolution of carbonate, gypsum, and silicate were identified as the prevalent hydrogeochemical processes contributing and defining spring water chemistry in this basin. Saturation indices(SI) of most major minerals studied in this region were below zero, indicating that these minerals remain under-saturated in the spring water in this area. Overall, the rank of different processes in terms of their contribution to the chemical composition of spring water in the YZRB was carbonate weathering > evaporate dissolution > silicate weathering > precipitation input. The content of 18 O in spring water ranged from-22.22‰ to-14.08‰ with a mean of-18.15‰. Samples collected below and close to the local and global meteoric water lines indicated that spring water in this area is derived from meteoric water with chemistry affected by evaporation.
  • Effects of drought and heat on the productivity and photosynthetic characteristics of alpine meadow plants on the Qinghai-Tibetan Plateau
    MA Li, ZHANG Zhong-hua, YAO Bu-qing, MA Zhen, HUANG Xiao-tao, ZHOU Bing-rong, XU Man-hou, GUO Jing, ZHOU Hua-kun
    2021, 18(08): 2079-2093.
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    Alpine meadow plants, adapted to humid and cold environments, are highly sensitive to environmental factors such as drought and heat. However, the physiological responses of individual alpine meadow species to drought and heat stress remain unclear. In this study, four representative species of typical functional groups in an alpine meadow of the Qinghai-Tibet Plateau were selected as experimental materials. Heat(H1, H2), drought(D1, D2), and combined stress(D1 H1, D2 H2) treatments were implemented to reveal the biomass and physiological characteristics' response to a constant drought and heat environment. Our results showed that the leaf water content(LWC) of Kobresia humilis and Poa annua increased significantly under heat stress and the compound stress(P<0.05). The effect of a single factor on LWC was greater than that of multiple factors. The aboveground biomass(AGB) of Oxytropis ochrocephala and Saussurea pulchra decreased significantly under compound stress(P<0.05). The response patterns of the net photosynthetic rate(Pn) and transpiration rate(Tr) of K. humilis and P. annua under various stress treatments were similar; as were those of O. ochrocephala and S. pulchra. The stomatal conductance(Gs) variation in K. humilis, P. annua, O. ochrocephala, and S. pulchra were the same under three kinds of stress treatments. The photosynthetic characteristics were more sensitive to the effects of composite than those of single factors. The drought × heat × species treatment had a significant influence on various indexes except on height(Ht) and the belowground biomass(BGB)(P<0.01). Within a certain range, daytime temperature(DT) promoted the Ht and increased the LWC of the plants, while it inhibited their AGB and intercellular CO2 concentration(Ci). The Pn, Tr, and Gs were more sensitive to soil moisture than to DT. The results help improve understanding of the physiological response regularity of representative alpine meadow plant species to continuous drought and high temperature conditions at the species level, and provided experimental data and theoretical basis to identify the decisive factors of stress response.
  • Landslide distribution and sliding mode control along the Anninghe fault zone at the eastern edge of the Tibetan Plateau
    ZHOU Hong-fu, LIU Bin, YE Fei, FU Wen-xi, TANG Wen-qing, QIN Ya-dong, FANG Tian
    2021, 18(08): 2094-2107.
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    Tibetan Plateau is known as the roof of the world. Due to the continuous uplift of the Tibetan Plateau, many active fault zones are present. These active fault zones such as the Anninghe fault zone have a significant influence on the formation of special geomorphology and the distribution of geological hazards at the eastern edge of the Tibetan Plateau. The Anninghe fault zone is a key part of the Y-shaped fault pattern in the Sichuan-Yunnan block of China. In this paper, high-resolution topographic data, multitemporal remote sensing images, numerical calculations, seismic records, and comprehensive field investigations were employed to study the landslide distribution along the active part of the Anninghe. The influence of active faults on the lithology, rock mass structures and slope stress fields were also studied. The results show that the faults within the Anninghe fault zone have damaged the structure and integrity of the slope rock mass, reduced the mechanical strength of the rock mass and controlled the slope failure modes. The faults have also controlled the stress field, the distribution of the plastic strain zone and the maximum shear strain zone of the slope, thus have promoted the formation and evolution of landslides. We find that the studied landslides are linearly distributed along the Anninghe fault zone, and more than 80% of these landslides are within 2-3 km of the fault rupture zone. Moreover, the Anninghe fault zone provides abundant substance for landslides or debris flows. This paper presents four types of sliding mode control of the Anninghe fault zone, e.g., constituting the whole landslide body, controlling the lateral boundary of the landslide, controlling the crown of the landslide, and constituting the toe of the landslide. The results presented merit close attention as a valuable reference source for local infrastructure planning and engineering projects.
  • A catastrophic natural disaster chain of typhoon–rainstorm–landslide–barrier lake–flooding in Zhejiang Province, China
    CUI Yu-long, HU Jun-hong, XU Chong, ZHENG Jun, WEI Jiang-bo
    2021, 18(08): 2108-2119.
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    On August 10, 2019, due to the effect of a rainstorm caused by Super Typhoon Lekima, a landslide occurred in Shanzao Village, China. It blocked the Shanzao stream, forming a barrier lake, and then the barrier lake burst. This is a rare natural disaster chain of typhoon–rainstorm–landslide–barrier lake–flooding. This study was built on field surveys, satellite image interpretation, the digital elevation model(DEM), engineering geological analysis and empirical regression. The purpose was to reveal the characteristics and causes of the landslide, the features and formation process of the barrier lake and the dam break flooding discharge. The results show that the volume of the landslide deposit is approximately 2.4 × 105 m3. The burst mode of the landslide dam is overtopping, which took only 22 minutes from the formation of the landslide dam to its overtopping. The dam-break peak flow was 1353 m3/s, and the average velocity was 2.8-3.0 m/s. This study shows that the strongly weathered rock and soil slope has low strength and high permeability under the condition of heavy rainfall, which reminds us the high risk of landslides and the importance of accurate early warning of landslides under heavy rainfalls in densely populated areas of Southeast China, as well as the severity of the disaster chain of typhoon–rainstorm–landslide–barrier lake–flooding.
  • Velocity profile of debris flow based on quadratic rheology model
    DU Cui, WU Wei-ming, MA Chao
    2021, 18(08): 2120-2129.
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    The quadratic rheology model considers the yield stress, viscous stress, turbulent stress and disperse stress, so it is used in this study to derive the velocity profile of debris flows. The quadratic model with the parabolic eddy viscosity was numerically solved, and an analytical solution was derived for the quadratic model with a constant eddy viscosity. These two solutions were compared with the Arai-Takahashi model that excluded the viscous stress and the yield stress. The three models were tested by using 17 experiment cases of debris flows over rigid beds. The results prove that the quadratic model with parabolic and constant eddy viscosities is applicable to muddy and granular flows, whereas the Arai-Takahashi model tends to overestimate the flow velocity near the water surface if a plug-like layer exists. In addition, the von Karman constant and the zero-velocity elevation in the three models are related to sediment concentration. The von Karman constant decreases first and then increases as the sediment concentration increases. The zero-velocity elevation is below the bed surface, likely due to the invalidity of the non-slip boundary condition for the debris flows over fixed beds.
  • Landslide prediction based on improved principal component analysis and mixed kernel function least squares support vector regression model
    LI Li-min, CHENG Shao-kang, WEN Zong-zhou
    2021, 18(08): 2130-2142.
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    Landslide probability prediction plays an important role in understanding landslide information in advance and taking preventive measures. Many factors can influence the occurrence of landslides, which is easy to have a curse of dimensionality and thus lead to reduce prediction accuracy. Then the generalization ability of the model will also decline sharply when there are only small samples. To reduce the dimension of calculation and balance the model's generalization and learning ability, this study proposed a landslide prediction method based on improved principal component analysis(PCA) and mixed kernel function least squares support vector regression(LSSVR) model. First, the traditional PCA was introduced with the idea of linear discrimination, and the dimensions of initial influencing factors were reduced from 8 to 3. The improved PCA can not only weight variables but also extract the original feature. Furthermore, combined with global and local kernel function, the mixed kernel function LSSVR model was framed to improve the generalization ability. Whale optimization algorithm(WOA) was used to optimize the parameters. Moreover, Root Mean Square Error(RMSE), the sum of squared errors(SSE), Mean Absolute Error(MAE), Mean Absolute Precentage Error(MAPE), and reliability were employed to verify the performance of the model. Compared with radial basis function(RBF) LSSVR model, Elman neural network model, and fuzzy decision model, the proposed method has a smaller deviation. Finally, the landslide warning level obtained from the landslide probability can also provide references for relevant decision-making departments in emergency response.
  • Bearing mechanism of a tunnel-type anchorage in a railway suspension bridge
    JIANG Nan, WANG Duo, FENG Jun, ZHANG Sheng-liang, HUANG Lin
    2021, 18(08): 2143-2158.
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    A tunnel-type anchorage(TTA) is one of the main components in suspension bridges: the bearing mechanism is a key problem. Investigating the deformation characteristics, development law, and failure phenomenon of a TTA under load can provide the theoretical basis for a robust design. Utilizing the TTA of the Jinsha River suspension bridge at Lijiang Shangri-La railway as a prototype, a laboratory model test of the TTA was carried out for three different contact conditions between the anchorage body and the surrounding rock. The stress and deformation distribution law of the anchorage body and its surrounding rock were studied, and the ultimate bearing capacity and failure mode of the TTA were analyzed. The test results show that the compressive stress level is highest at the rear part of the anchorage body. Moving away from the rear portion of the body, the stress decays in a negative exponential function. Based on the load transfer curve, the calculation formula for the shear stress on the contact surface between the anchorage body and the surrounding rock was derived, which shows that the distribution of the shear stress along the axial direction of the anchorage body is not uniform. The distance from the maximum value to the loading surface is approximately 1/3 of the length of the anchorage body, and the stress decreases as the distance from the loading surface increases. Furthermore, the contact condition between the anchorage body and surrounding rock has a great influence on the bearing capacity of the TTA. The increase in the anti-skid tooth ridge and radial anchor bolt can improve the cooperative working capacity of the anchorage body and the surrounding rock, which is approximately 50% higher than that of the flat contact condition. The main function of the anchor bolt is to increase the overall rigidity of the TTA. The contact condition between the anchorage body and the surrounding rock will lead to a change in the failure mode of the TTA. With an increase in the degree of contact, the failure mode will change from shear sliding along the interface to trumpet-shaped inverted cone-shaped failure extending into the surrounding rock.
  • Field experiment of rainfall infiltration on a soil slope and simulations based on a water-air two-phase flow model
    LIU Gang, ZHA Xin-yuan, GUAN Jin-kun, TONG Fu-guo
    2021, 18(08): 2159-2167.
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    Rainfall infiltration on a soil slope is usually an unsaturated seepage process that can be described by a water-air two-phase flow model. The effect of pore air pressure on rainfall infiltration has been widely recognized and validated by means of numerical simulations and laboratory experiments. However, whether a slope can actually seal pore air continues to be debated by researchers. In this study, a water-air two-phase flow model is used to simulate the rainfall infiltration process on a soil slope, and a field experiment is conducted to realistically test the sealing conditions of a slope. According to the numerical simulation, the areas of water and air flow in and out on the slope surface are relatively stable and can be classified as the "inhalation zone" and "overflow zone", respectively. Intermittent rainfall on the soil slope has an amplifying effect on pore air pressure because rainfall intensity is usually at the millimeter level, and it causes pore air pressure to reach the cm level. A field experiment was performed to determine whether a slope can realistically seal pore air and subsequently verify the regularity of rainfall infiltration. Air pressure sensors were buried in the slope to monitor the pore air pressures during the rainfall process. The monitoring results show that the pore air pressure in the slope changed, which indicates that the slope can seal air. Moreover, the amplification effects of intermittent rainfall on pore air pressure were observed for natural rainfall, which agrees well with the numerical simulation results.
  • Variations of suction and suction stress of unsaturated loess due to changes in lignin content and sample preparation method
    LIU Wei, WANG Qian, LIN Gao-chao, XU Xiang-tian
    2021, 18(08): 2168-2183.
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    Unsaturated loess in natural sites loses stability as the overburden load continuously increases. Traditional soil modifiers such as cement and fly ash affect the surrounding environment. A new type of material, i.e., lignin, is environmentally friendly and able to increase the strength of loess. However, the engineering characteristics of the improved loess under unsaturated conditions are not yet clear. In this study, the soil-water characteristic curves(SWCCs) of lignin-improved loess samples were determined from 0 k Pa to 700 k Pa using a pressure plate instrument, and then, they were fitted using the van Genuchten(VG) model and the Fredlund and Xing(FX) model. In addition, the effects of the lignin content and sample preparation methods on the SWCCs were investigated to determine the optimal lignin content and a suitable sample preparation method for loess foundations. As the lignin content increases, the matric suction and residual water content of the improved loess increase. The suction stress increases with the increasing lignin contents of 1%-2%. At lignin contents of 3%-4%, the suction stress begins to decrease and the samples prepared using the slurry method has a lower suction stress than that prepared using the wet mixing method. The air entry value(AEV) increases with increasing lignin content. In addition, scanning electron microscopy(SEM) was used to investigate the microstructural variations. It was found that after the addition of lignin, the entrapment of the loess particles by the lignin fibers created some larger particles and smaller pore diameters, which in turn led to poor connectivity of the loess pores. These changes cause the matric suction of the modified loess to increase.
  • Do historical maps show the maximal anthropopressure in the Carpathians?
    Micha? SOBALA
    2021, 18(08): 2184-2200.
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    Many landscapes bear the marks of historical land use. These marks can be the basis for a reconstruction of a historical land use structure as some of them are typical of different types of human activity. The aim of this paper is to determine whether Austrian cadastral maps from the 19 th century present the image of the most transformed environment in the Western Carpathians as a result of agricultural activity. Land use structure and terrain forms were detected based on Austrian cadastral maps from 1848, airborne laser scanning and field studies. In two of the test areas, the percentage of arable fields was higher among the plots with stone mounds than the percentage among the plots without them. In the third test area, the relationship was reversed. Also, lynchets, terraces and stone walls sometimes occur in plots that were not arable fields in 1848. Thus, the Austrian cadastral maps from 1848 could not reflect the maximal range of arable fields in the Carpathians in the 19 th century. However, it is impossible to determine the historical structure of land use precisely. Nevertheless, an inventory of terrain forms can be used to assess land use when historical maps have not preserved or when available maps do not present land use in detail.
  • Grass-livestock balance based grassland ecological carrying capability and sustainable strategy in the Yellow River Source National Park, Tibet Plateau, China
    YU Hui, LIU Bin-tao, WANG Gen-xu, ZHANG Tong-zuo, YANG Yan, LU Ya-qiong, XU You-xue, HUANG Min, YANG Yi, ZHANG Lv
    2021, 18(08): 2201-2211.
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    The Yellow River Source National Park(YRSP) is one of the most sensitive and fragile ecological regions in the world. The historical intensive grazing and climate change have resulted in ecological degradation that threatens the wildlife and livestock. Exploring the sustainable strategy is urgent for policy makers to meet the demands for wild ungulates and livestock. In our study, the grassland ecological carrying capability(GECC) was assessed based on the updated grass-livestock balance that considered the grass competition from wild ungulates. The balances between grass and livestock, and GECC and grassland pressure index(GPI) in the YRSP were measured through overlay analysis and geostatistic analysis. The results showed that:(1) the ratio of livestock to wild ungulates in the research area was approximately 4.56: 1, in which the proportion of livestock was 81.75% and the actual number of livestock was 33.84 × 104 standard sheep units;(2) Under the scenario of minimum grazing utilisation rate, the theoretical grazing capacity and GECC were 37.83 × 104 standard sheep units and-0.13, respectively. Under the maximum grazing utilisation rate, the theoretical grazing capacity and GECC were 41.93 × 104 standard sheep units and-0.21, respectively. Since GECC in both scenarios were both less than 0, the grassland was considered to be in surplus and the livestock was not overloaded. However, GPI in the two scenarios were 0.87 and 0.79, respectively, both of which exceeded the warning line of 0.70. Based on GECC, we recommend that the sustainable strategy in YRSP is either to increase the supplementary feeding about 6.40 × 104 standard sheep units or reduce the grazing livestock by about 3.50 × 104 standard sheep units.