过刊目录

  • 2020年, 17卷, 第10期
    刊出日期:2024-06-19
      

  • 全选
    |
  • Janusz GODZIEK, Krzysztof GAIDZIK
    2020, 17(10): 2297-2320.
    Inherited tectonic structures, ongoing tectonic deformation, and variations in relative rock uplift rates play an important role in conditioning the processes of relief development. Their influence among other factors, such as climate and lithology, can be quantified using landscape analysis, and geomorphometric indices, in particular. The usage of landscape analysis in recent years is increasing systematically due to the constant improvement of the digital elevation models and GIS software that significantly facilitate this approach. In this study, we aim to recognize the influence of tectonic structures and processes on relief development in the low mountains with moderate relief of the So?a River catchment in the Western Outer Carpathians. To this end, we calculated geomorphometric indices(river longitudinal profile, stream-length gradient index, minimum bulk erosion, relief ratio, circulatory ratio, elongation ratio, and hypsometric integral) for the So?a River and its 47 sub-catchments using a 25-m spatial resolution Digital Terrain Elevation Data Level 2. Additionally, we identified lineaments and knickpoints and correlated the computed results with local and regional fault networks, variations in lithology, and climate fluctuations. Obtained results indicate a significant impact of inherited tectonicstructures on the relief development of the So?a River catchment, i.e., directions of principal ridges and valleys follow the orientation of main folds and faults recorded in this area. Anomalously high values of minimum bulk erosion, river gradient, and streamlength gradient index allowed us to define two areas with higher relative uplift rates: 1) the So?a Gorge and 2) the Beskid ?ywiecki Mts. Polish Outer Carpathians are generally considered as an area of low strain rate and low seismic activity. However, the possibility of neotectonic processes should be considered in geohazard estimations. Observed bends in the direction of river valleys that do not correspond with changes in lithology could be related to active strikeslip faults. These are probably the reactivated basement structures, copied in the thin-skinned nappe cover, as a result of the accommodation of the Mur-?ilina Fault Zone resulting from the tectonic push of the Alcapa(Alpine-Carpathian-Pannonian) microplate against the European plate. Thus, the role of recent tectonic activity in relief development of the So?a River catchment even though appears to be subsidiary at the most, should not be excluded.
  • Robert SYSOLYATIN, Sergei SERIKOV, Mikhail ZHELEZNYAK, Yana TIKHONRAVOVA, Yuri SKACHKOV, Vladimir ZHIZHIN, Maria ROJINA
    2020, 17(10): 2321-2338.
    In recent decades, research of the Alps, Qinghai-Tibet Plateau, and Cordillera have made great progress in understanding the phenomenon of permafrost. For the most part, this has been made possible due to temperature monitoring. However, the permafrost parameters in an area of more than 2 million square km of the mountainous regions of northeast Asia, for the most part, remain a blank spot in the scientific community. Due to the lack and insufficiency of factual materials, in 2012 the P.I. Melnikov Permafrost Institute began to take temperature measurements in the upper part of the permafrost in the central part of the VerkhoyanKolyma uplands, namely the Suntar-Khayat ridge. The article describes the temperature characteristics of air, surface and rocks of the active layer in the range of heights from 850 to 1821 m, in various landscape and topographic elements. For the observation period from 2012 to 2019, we obtained information on temperatures in the soils of the active layer at depths of 1 m, 3 m, 4 m, and 5 m and also air and surface temperature parameters. The availability of data on automated monitoring of rock temperatures in the active layer and the upper horizons of the layer of annual heat rotations made it possible to substantiate the most typical conditions of the temperature conditions of the permafrost zone of the characterized region. The parameters of permafrost existence and development are in favorable conditions. This is shown in the analysis of temperature data of air, surface and active layer. Soil temperatures in the active layer of annual heat rotations are most clearly represented at a depth of 1 m. Currently, on the territory of the mountain regions of Eastern Siberia, there are no more such sites for monitoring the temperature regime of soils. Information on the permafrost parameters in the region will allow us to begin the process of creating new models or checking existing forecasts and the distribution of the temperature pattern. It will also make it possible to evaluate the response of sensitive and vulnerable frozen soils of mountain regions to climate change.
  • Andrey A.GRIGORIEV, Yulia V.SHALAUMOVA, Olga V.EROKHINA, Svetlana Yu.SOKOVNINA, Elizaveta I.VATOLINA, Martin WILMKING
    2020, 17(10): 2339-2353.
    Shrub expansion into arctic and alpine tundra is one of the prominent vegetation changes currently underway. We studied the expansion of shrub vegetation into high elevation tundra in the Kvarkush Range of the Northern Ural mountains, Russia. Age structure analysis of the dominant shrub Juniperus sibirica Burgsd. seems to support ongoing upslope advance of shrubs, a process particularly active in the second half of the 20 th century. We found a close connection between the expansion of shrub vegetation and the general change in climatic conditions of the cold season(months with mean airtemperature below 0°С from November to March). In general, the greatest influence on the distribution of J. sibirica is exerted by the climate conditions of the beginning(November-January) and the end(March) of the cold season. With increasing elevation, the correlation coefficients between the establishment of J. sibirica shrubs and the precipitation of the beginning of the cold season increased, and reached maximum values at the top elevation level of the study area. However, the upwards shift of J. sibirica into typical mountain tundra does not lead to changes in the ecological structure of vegetation at this stage, but simply a decrease in the area of mountain tundra.
  • Parveen K.CHHETRI, Raju BISTA, Krishna B.SHRESTHA
    2020, 17(10): 2354-2368.
    Stand structure dynamics are considered as major happenings in any forest as a response to environmental changes. However, this important topic is underrepresented in the treeline studies in the Nepal Himalayas. We aimed to investigate site-as well as species-specific changes in morphometric features(basal diameter, crown cover, density, and height) along the elevational gradient across treeline ecotones in response to recent environmental changes. The stand structure characteristics of Abies spectabilis, Pinus wallichiana, and Betula utilis across the treeline ecotone of three study sites in Eastern(Barun), Central(Manang), and Western(Dhorpatan) Nepal were analyzed to elucidate structural heterogeneities. Altogether, eight transects(20 m ×(60–250 m)) across the treeline ecotone were established. Trees of all life forms, trees(> 2 m), saplings(0.5–2 m), and seedlings(< 0.5 m), within each transect were enumerated and sampled for the morphometric features and age. Site-specific and species-specific stand structure dynamics were found. The rate of basal area increment was higher in Barun, but the Manang treeline, despite profound regeneration in recent years, had a low annual basal area increment. Moreover, the altitudinal distribution of age and morphometry were not consistent among those ecotones. Furthermore, intra-specific competition was not significant. The site-specific stand structure dynamics explain why treelines do not respond uniformly to increasing temperature. It invokes, in further studies, the incorporation of the tree's morphometric adaptation traits, phenotypic plasticity, and interactions between species genotype and the environment.
  • Maksymilian SOLARSKI, Miros?aw SZUMNY
    2020, 17(10): 2369-2386.
    This research aimed to identify the impact of local climatic and topographic conditions on the formation and development of the ice cover in highmountain lakes and the representativeness assessment of periodic point measurements of the ice cover thickness by taking into consideration the role of the avalanches on the icing of the lakes. Field works included measurement of the ice and snow cover thickness of seven lakes situated in the Tatra Mountains(UNESCO biosphere reserve) at the beginning and the end of the 2017/2018 winter season. In addition, morphometric, topographic and daily meteorological data of lakes from local IMGW(Polish Institute of Meteorology and Water Management) stations and satellite images were used. The obtained results enabled us to quantify the impact of the winter eolian snow accumulation on the variation in ice thickness. This variation was ranging from several centimetres up to about 2 meters and had a tendency to increase during the winter season. The thickest ice covers occurred in the most shaded places in the direct vicinity of rock walls. The obtained results confirm a dominating role of the snow cover in the variation of the ice thickness within individual lakes.
  • Selcuk ALEMDAG, Enver AKARYALI, Mehmet Ali GüCER
    2020, 17(10): 2387-2404.
    One of the leading factors of seepage contamination is mine drainage, which creates serious ecological risks on the environment both during operation and post-mining times. In this study, experimental processes have been carried out to determine the occurrence of mine drainage in the Gümü?k?y(Kütahya) mineralization area(Northwest Turkey). The prevention method for potential mine drainage occurrence has been also discussed. High enrichment was observed which are directly related to mineralization in trace element concentrations, especially in potentially toxic metals such as Ag, Cd, Mo, Ba, Bi, and Zn. Based on short-term tests, mine drainage formation has not been expected according to the p H(7.36-9.38), contact leaching, and acid-base accounting studies. However, in the long-term, acid generation potential has been expected because of weathering and oxidation in terms of rock type and mineralization in the area. Therefore, in order to prevent groundwater contamination in the event of a possible formation of mine drainage, the hydraulic conductivity of the stock area bedrock was evaluated by the in situ tests performed in the field and it was found to be moderately permeable(K= 1.9 × 10~(-6) m/s). In order to make the stock area bedrock impermeable,natural clay will be laid and compressed at the base of the stock area. When the finite elements were modeled by seepage analysis, the seepage discharge to be formed on the base rock at a depth of 5 m was determined as 3.17 × 10~(-19) m~3/s. Since the discharge value determined in the seepage analysis after modeling is very close to zero, contamination of possible ground and surface water will be prevented.
  • Wael A.OBAID, Tahar BOUTRAA
    2020, 17(10): 2405-2417.
    Ohud mountain is one of the main important historic sites in the Arab Peninsula, and it is distinguishable over the rest of the mountains in the region. No extensive floristic survey has been carried out on Ohud mountain because of the rugged topography of this mountain. The current study investigates the floristic diversity and the correspondence of environmental factors of the phytogeographical distribution of plants, based on the floristic analysis of the present region. The research question is about the relationships between the species diversity and the human impacts of populated area at lowlands around Ohud mountain. A total of 59 species belonging to 56 genera and 28 families were recorded. Asteraceae had the highest contribution, about 12% of the total plant species. The analysis of the life forms demonstrated the prevalence of therophytes(68%) followed by chamaephytes(24%), indicating the adaptation of these life forms to hyperarid conditions. The chorological analysis indicated the predominance of the bi-regional taxa over the other phytochoria. Most of the recorded plant species belong to Saharo-Arabian and Sudano-Zambezian(24%) phytochoria. TWINSPAN analysis was performed to detect the indicator species of different vegetation groups and confirmed by detrended correspondence analysis(DCA or DECORANA). It is concluded that species richness and diversity revealed clear variation along the mountain and among the studied sites. Plant species diversity and richness were more pronounced in the intermediate portion of the elevation gradients across the mountain, with a decrease in the high altitudinal belts. The decrease was also recorded at the lower altitudes, where human impacts clearly affected vegetation; leading to a decrease in alpha diversity. In addition, the beta diversity among moderately highlands and lowlands was considerably high indicating the heterogeneous species composition among the studied sites along mountain elevations. The general pattern of vegetation groups distribution is controlled by a number of environmental factors; such as latitude, longitude, elevation, organic matter and some anions and cations. A Canonical Correspondence Analysis(CCA) ordination revealed that the vegetation structure has a strong association with the latitude of the mountain followed by organic matter and Magnesium. It is recommended that the populated area should be subjected to restoration of mountain ecosystem that might be degraded by human activities.
  • ZHANG Guan-hua, DING Wen-feng, PU Jian, LI Jian-ming, QIAN Feng, SUN Bao-yang
    2020, 17(10): 2418-2431.
    Biological soil crusts(biocrusts) are important landscape components that exist in various climates and habitats. The roles of biocrusts in numerous soil processes have been predominantly recognized in many dryland regions worldwide. However, little is known about their effects on soil detachment process by overland flow, especially in humid climates. This study quantified the effects of moss-dominated biocrusts on soil detachment capacity(Dc) and soil erosion resistance to flowing water in the Three Gorges Reservoir Area which holds a subtropical humid climate. Potential factors driving soil detachment variation and their influencing mechanism were analyzed and elucidated. We designed five levels of coverage treatments(1%–20%, 20%–40%, 40%–60%, 60%–80%, and 80%–100%) and a nearby bare land as control in a mossdominated site. Undisturbed soil samples were taken and subjected to water flow scouring in a hydraulic flume under six shear stresses ranging from 4.89 to 17.99 Pa. The results indicated that mean Dc of mosscovered soil varied from 0.008 to 0.081 kg m~(-2) s~(-1), which was 1.9 to 21.0 times lower than that of bare soil(0.160 kg m~(-2) s~(-1)). Rill erodibility(Kr) of mosscovered soil ranged from 0.0095 to 0.0009 s m~(-1), which was 2 to 20 times lower than that of bare soil(0.0187 s m~(-1)). Both relative soil detachment rate and Kr showed an exponential decay with increasing moss coverage, whereas the critical shear stress(τc) for different moss coverage levels did not differ significantly. Moss coverage, soil cohesion, and sand content were key factors affecting Dc, while moss coverage and soil bulk density were key factors affecting Kr. A power function of flow shear stress, soil cohesion, and moss coverage fitted well to estimate Dc(NSE=0.947). Our findings implied that biocrusts prevented soil detachment directly by their physical cover and indirectly by soil properties modification. Biocrusts could be rehabilitated as a promising soil conservation measure during ecological recovery to enhance soil erosion resistance in the Three Gorges Reservoir Area.
  • Ayehu FEKADU, Teshome SOROMESSA, Bikila Warkineh DULLO
    2020, 17(10): 2432-2446.
    Climate change is thought to have a greater impact on crops that require particular conditions for their productivity. Southwest Ethiopia is a region where important cash crops such as Coffea arabica and Aframomum corrorima(korerima) originate. These crops are known to require shade for their growth and productivity. This study was conducted to assess the impacts of climate change on an important but neglected cash crop of A. corrorima using GIS-based species distribution approaches. Local meteorological data and bioclimatic data from WorldClim were used to map past, present, and future distribution of the crop in the Coffee Forest System of Southwest Ethiopia. Moreover, 96 key informants were interviewed and completed questionnaires to complement the distribution modeling. The key informants mapped the history and present occurrences of A. corrorima and based on this, ground-truthing survey was conducted. The interpolation method of the Inverse Distance Weighted was used in ArcGIS 10.5 to develop bioclimatic variables for modeling past and present distribution while data from IPCC(AR_4) Emissions Scenarios was used for the future occurrence prediction using Principal Component Analysis. Eleven best bioclimatic variables were selected and MaxEnt was used to model past, present and future distribution of A. corrorima. The output of our model was validated using Area Under the Curve(AUC) approach. Temperature and precipitation are the most important environmental variable, then temperature increased by 1.3°C in the past(from 1988 to 2018) while it is predicted to increase further by at least 1.4°C before 2050. On the contrary, precipitation decreased by an average of 10.1 mm from the past while it is predicted to decrease further by 12.5 mm before 2050. Our model shows that the area suitable for korerima in 1988 was 20,638.2 ha and it was reduced by half and became 10,545.3 ha in 2018, similarly predicted to shrink into 3225.5 ha by 2050. The findings from the key informants confirm the model results whereby 89.1% of the respondent replied korerima producing area has been shifted into the mountains over the last 30 years(by 150 m a.s.l. from 1988 to 2018) and thus expected to be pushing up in the next 32 years(by 133 m before 2050). The community claims that the length of the rainy season of the area has been shortening from 9 months in the past to an average of 5.5 months recently which also coincides with increasing temperature. We conclude that with the changing climatic condition, the suitable habitat of korerima has already shrank by 48.9%(from 1988 to 2018) and the trend may lead to a shrink by 84.38% before 2050(from 1988 to 2050). Therefore, it is important to develop site-specific climate adaptation strategies for the region such as promoting alternative livelihoods and avoiding further coffee forest degradation and deforestation.
  • Kamal H.SHALTOUT, Yassin M.AL-SODANY, Ebrahem M.EID, Selim Z.HENEIDY, Mostafa A.TAHER
    2020, 17(10): 2447-2458.
    South Sinai includes Egypt's highest mountains that resemble an ecological island surrounded by desert. The present study aims to analyse the vegetation physiognomy along the altitudinal and environmental gradients in the main wadi beds in South Sinai mountainous region. This includes determining the natural, native-weed and alien vegetation in representative stands in this region, analysing their vegetation in terms of species composition, abundance and life forms and determining the national and global distribution of the associated species. This investigation also aims to describe the prevailing plant communities and assess the role of environmental conditions that affect the vegetation in this region. Thus, thirty-two stands were chosen during March-June 2018 to reflect the prevailing altitude and environmental gradients. Total species was 316(229 genera and 61 families): 186 species were perennials(58.9%), while 130 were annuals(41.1%). In addition, 152 species were native weeds(48.1% of total species), 31 were aliens(9.8%), along with 133 natural species(42.1%). Eight species were recorded as endemic to Egypt: Anarrhinum pubescens, Euphorbia sanctae-catharinae, Hypericum sinaicum, Origanum syriacum subsp. sinaicum, Phlomis aurea, Primula boveana, Rosa arabica and Solanum sinaicum. In addition, 10 species were recorded as near-endemics to Egypt and other adjacent countries: Allium desertorum, Asclepias sinaica, Centaurea scoparia, Fagonia mollis var. hispida, Hyoscyamus boveanus, Iphiona mucronata, Micromeria sinaica, Pterocephalus sanctus, Salvia deserti and Stachys aegyptiaca. In the present study, 33 species are threatened and categorized as follows: 8 endangered, 8 vulnerable and one indeterminate, while the rest were evaluated by the authors as rares. The rich plant diversity of this region is due to its extensive mountainous massif, which supports many microhabitats. The high elevations in this region hinder the dispersal process of propagules, a situation which often tends to increase endemic and near-endemic species. The current results were discussed and compared with some related previous studies.
  • Augusto ZANELLA, Jean-Fran?ois PONGE, Anna ANDREETTA, Michael AUBERT, Nicolas BERNIER, Eleonora BONIFACIO, Karine BONNEVAL, Cristian BOLZONELLA, Oleg CHERTOV, Edoardo A.C.COSTANTINI, Maria DE NOBILI, Silvia FUSARO, Raffaello GIANNINI, Pascal JUNOD, Klaus KATZENSTEINER, Jolantha KWIATKOWSK-MALINA, Roberto MENARDI, Lingzi MO, Safwan MOHAMMAD, Annik SCHNITZLER, Adriano SOFO, Dylan TATTI, Herbert HAGER
    2020, 17(10): 2459-2484.
    At the end of October 2018, a storm of unprecedented strength severely damaged the forests of the eastern sector of the Italian Alps. The affected forest area covers 42,500 ha. The president of one of the damaged regions asked for help from the University of Padua. After eight months of discussion, the authors of this article wrote a consensus text. The sometimes asper debate brought to light some crucial aspects: 1) even experienced specialists may have various opinions based on scientific knowledge that lead to conflicting proposals for action. For some of them there is evidence that to restore a destroyed natural environment it is more judicious to do nothing; 2) the soil corresponds to a living structure and every ecosystem's management should be based on it; 3) faced with a catastrophe, people and politicians find themselves unarmed, also because they rarely have the scientific background to understand natural processes. Yet politicians are the only persons who make the key decisions that drive the economy in play and therefore determine the near future of our planet. This article is an attempt to respond directly to the governor of a region who formally and prudently asked a university department called "Land, Environment, Agriculture and Forestry" for help before taking decisions; 4) the authors also propose an artistic interpretation of facts(uncontrolled storm) and conclusions(listen to the soil). Briefly, the authors identify the soil as an indispensable source for the renewal of the destroyed forest, give indications on how to prepare a map of the soils of the damaged region, and suggest to anchor on this soil map a series of silvicultural and soil management actions that will promote the soil conservation and the faster recovery of the natural dynamic stability and resilience.
  • YU Yan-ping, ZHANG Ke-cun, AN Zhi-shan, WANG Tao, HU Fei
    2020, 17(10): 2485-2496.
    Fences are one of the most effective measures to prevent and control wind-blown sand disasters, and the blocking effect of fences is largely determined by their porosity and height(H). This study employed wind tunnel experiments to measure wind velocities on both sides of wire mesh sand fences with porosities of 75%, 63%, 56%, 36% and heights of 10, 5 and 2 cm. The effects of porosity and height on the blocking effect of the fences were evaluated on the basis of velocity variability, flow field, and the wind velocity reduction coefficient. Results show that the smaller the porosity, the stronger the blocking effect. The fence with a porosity of 36% had the strongest windproof efficiency of 0.70 and longest protection range of 9 H, and thus showed the best applicability in preventing and controlling wind-blown sand disasters. The fence with a porosity of 56% showed a windproof efficiency of 0.31 and a protection range of 7 H, which could be considered for adoption. However, fences with porosities of 75% and 63% were not recommended to be adopted, because their windproof efficiency and protection range were very small. Overall, the higher the fence, the stronger the blocking effect. The highest fence(10 cm) had the longest protection range of 90 cm, which was the best in application. Nevertheless, the 5 and 2 cm fences were almost consistent with 10 cm fence in windproof efficiency, which was still suitable for wind and sand fixation.
  • WANG Xiao-qun, HUANG Xin, SHEN Man, ZHOU Zhou, WEI Jie
    2020, 17(10): 2497-2511.
    The Diexi ancient dammed lake is in the upper reaches of the Minjiang River. Six terraces with lacustrine sediments occur at the base. These terraces are the products of the graded outburst of the Diexi ancient dammed lake. The outburst of the ancient dammed lake would certainly have had an impact on the Chengdu Plain in the lower reaches of the Minjiang River. In this paper, on-site sampling and laboratory analysis were used to analyze the sediments of the Diexi ancient dammed lake and the Jinsha site in Chengdu Plain, and the environmental indicators of each sediment layer were tested. Through a comparative analysis of the environmental indicators in the sediments at the two locations, the following results were obtained: the palaeoclimatic and palaeoenvironmental characteristics at the two locations generally show consistent changes. The most important finding is that the types and content of the major pollen taxa at the two locations are similar. The Pinus content strongly proves that the soil layers at the Jinsha site was sourced from the upper reaches of the Minjiang River. Considering that the demise of the ancient culture at the Jinsha site occurred close in time to the outburst of the ancient dammed lake, this similarity suggests that the cultural change at the Jinsha site may have been related to the outburst of the Diexi ancient dammed lake.
  • Fausto O.SARMIENTO
    2020, 17(10): 2512-2527.
    Mountains as archetype frame some metageographies of the vertical dimension. Mountain metaphors, thus, have remained as key guidance in developing not only animistic belief systems and religious cults, but also military strategies, economic potential, and scientific innovation. This paper seeks to explain the need to integrate western knowledge, where mountains became known via natural history's mechanistic explanations, with other epistemologies. Mountain scientists therein developed linear approaches that required exploration, experimentation, and pragmatic interpretation of generalizable mountain phenomena. Little is known, however, about other civilizations' more encompassing cognition due to heuristic explanations of mountain myths. Local knowledge holders therein developed approaches that required familiarization, observation, and romantic meditation about situated mountain phenomena. Using a multimethod approach of human geography that includes onomastics, geocritical discourse analysis, political ecology, and critical biogeography, the author posits that there is a paradigmatic shift of geographic fad, when even "nature" is thought of as a "social construct" in the socioecological mountainscapes. Between these tendencies of either Cartesian or Spinozan dogmas about scientific objectives, methods and implications, mountains continue to elicit geographical research. The author thus concludes that integrating narratives of mountain studies with geocritical analyses of political ecology that allow for transgressivity and referentialilty of mountain cognition can be done with transdisciplinary science. Montology, henceforth, couples dialectic thinking with the trifecta of spatiality, complexity and historicity in highlighting mountain microrefugia for biocultural conservation. Use of montological approaches will bring mountain scientists to a new level, where the application of local ecological knowledge and cutting-edge technological instrumentation could render sustainable mountain communities, in dynamic biocultural heritage scenarios.
  • PU Jun-wei, ZHAO Xiao-qing, MIAO Pei-pei, LI Si-nan, TAN Kun, WANG Qian, TANG Wei
    2020, 17(10): 2528-2547.
    The karst mountainous area is an ecologically fragile region with prominent humanland contradictions. The resource-environment carrying capacity(RECC) of this region needs to be further clarified. The development of remote sensing(RS) and geographic information system(GIS) provides data sources and processing platform for RECC monitoring. This study analyzed and established the evaluation index system of RECC by considering particularity in the karst mountainous area of Southwest China; processed multisource RS data(Sentinel-2, Aster-DEM and Landsat-8) to extract the spatial distributions of nine key indexes by GIS techniques(information classification, overlay analysis and raster calculation); proposed the methods of index integration and fuzzy comprehensive evaluation of the RECC by GIS; and took a typical area, Guangnan County in Yunnan Province of China, as an experimental area to explore the effectiveness of the indexes and methods. The results showed that:(1) The important indexes affecting the RECC of karst mountainous area are water resources, tourism resources, position resources, geographical environment and soil erosion environment.(2) Data on cultivated land, construction land, minerals, transportation, water conservancy, ecosystem services, topography, soil erosion and rocky desertification can be obtained from RS data. GIS techniques integrate the information into the RECC results. The data extraction and processing methods are feasible on evaluating RECC.(3) The RECC of Guangnan County was in the mid-carrying level in 2018. The midcarrying and low-carrying levels were the main types, accounting for more than 80.00% of the total study area. The areas with high carrying capacity were mainly distributed in the northern regions of the northwest-southeast line of the county, and other areas have a low carrying capacity comparatively. The coordination between regional resource-environment status and socioeconomic development is the key to improve RECC. This study explores the evaluation index system of RECC in karst mountainous area and the application of multisource RS data and GIS techniques in the comprehensive evaluation. The methods can be applied in related fields to provide suggestions for data/information extraction and integration, and sustainable development.
  • LI Cong, ZHANG Rong-tang, ZHU Jie-bing, LIU Zhi-jun, LU Bo, WANG Bin, JIANG Yu-zhou, LIU Jie-sheng, ZENG Ping
    2020, 17(10): 2548-2561.
    The long-term stability of a prestressed anchored slope might be influenced by the durability of the anchorage structure. To understand long-term stability of anchored rock slopes, the research presented herein evaluated the performance evolution of a prestressed anchored bedding slope system in a corrosive environment by model test. The corrosion process in a prestressed anchor bar was monitored in terms of its open-circuit potential(OCP), corrosion current density(CCD), and electrochemical impedance spectroscopy(EIS). The stability of the prestressed anchored slope was evaluated by monitoring changes in anchorage force and displacements. The experimental results show that prestress and oxygen could reduce the corrosion resistance of the anchor bar, and anchor bars in a chloride-rich environment are very susceptible to corrosion. Prestressed tendons in a corrosive environment suffer a loss of anchorage force, the prestress decreases rapidly after locking, and the rate thereof decreases until stabilising; in the later stage, corrosion leads to the reduction of the cross-sectional area of the steel bar which may cause the reduction in anchorage force again. Anchorage force controls the deformation and stability of the anchored slope, the prestress loss caused by later corrosion may lead to an increased rate of displacement and stability degradation of the prestressed anchored rock slope.
  • YU Shu-hui, DENG Wei, XU You-xin, ZHANG Xia, XIANG Hao-lin
    2020, 17(10): 2562-2576.
    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.
  • LIU Zi-zhen, YAN Zhi-xin, QIU Zhan-hong, WANG Xiao-gang, LI Ji-wei
    2020, 17(10): 2577-2590.
    Based on the principle of saturated infiltration and the Green-Ampt model, an unsaturated infiltration model for a soil slope surface was established for either constant moisture content, or depth-varying moisture content and the slope. Infiltration parameters in the partially saturated slope were revealed under sustained rainfall. Through analysis of the variation of initial moisture content in the slope, the ponding time, infiltration depth, and infiltration rate were deduced for an unsaturated soil slope subject to rainfall infiltration. There is no ponded water on the surface of the slope under sustained low-intensity rainfall. The results show that the infiltration parameters of an unsaturated slope are influenced by the initial moisture content and the wetting front saturation, the soil cohesion and rainfall intensity under sustained rainfall. More short-term slope failures can occur with the decrease of cohesion of the soil of the slope. The ponding time and infiltration depth differ considering constant or different initial moisture content respectively in the soil slope. Then, best-fit curves of the infiltration rate, ponding time, and infiltration depth to the wetting front saturation were obtained with constant or different initial moisture contents. And the slope failure time is roughly uniform when subject to a rainfall intensity I>5 mm/h.