Soil erosion assessment and its verification using the Universal Soil Loss Equation and Geographic Information System: a case study at Boun,Korea

This study is aimed at the evaluation of the hazard of soil erosion and its verification at Boun, Korea, using a Geographic Information System (GIS) and remote sensing. Precipitation, topographic, soil, and land use data were collected, processed, and constructed into a spatial database using GIS and remote sensing data. Areas that had suffered soil erosion were analysed and mapped using the Universal Soil Loss Equation (USLE). The factors that influence soil erosion are rainfall erosivitiy (R) from the precipitation database, soil erodibility (K) from the soil database, slope length and steepness (LS) from the topographic database, and crop and management (C) and conservation supporting practices (P) from the land use database. Land use was classified from Landsat Thematic Mapper satellite images. The soil erosion map verified use of the landslide location data. Landslide locations were identified in the Boun area from interpretation of aerial photographs and field surveys.     

Assessing selected natural and anthropogenic impacts on freshwater lens morphology on small barrier Islands: Dog Island and St. George Island, Florida, USA

Abstract The freshwater lens morphologies of the barrier islands Dog Island and St. George Island on the panhandle coast of Florida (FL), USA, are controlled to varying degrees by both natural and anthropogenic factors. Variable-density groundwater flow models confirm that spatial variability of recharge values can account for the observed lens asymmetry on these islands. The depth to the base of the lens does not vary significantly seasonally. Human development has altered recharge patterns in some areas, locally thinning the freshwater lens. Aqueduct water supply to St. George Island represents 7–25% of natural recharge; higher recharge rates are required to simulate the lens on St. George Island than on Dog Island. On both islands, coastal erosion rates are sufficiently rapid that the freshwater lens may not be in equilibrium with current boundary conditions.

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Resumen Las morfologías de los lentes de agua dulce en las islas de barrera: Islas Dog y St. George, en la costa alargada y estrecha de Florida, EUA, están controladas en diferentes grados por factores antropogénicos y naturales. Los modelos de flujo con densidad variable del agua subterránea, confirman que la variabilidad espacial de los valores de recarga, pueden ser la causa de la asimetría observada en los lentes de estas islas. La profundidad hasta la base de los lentes no varía significativamente con las estaciones climáticas. El desarrollo humano ha alterado las tendencias de recarga en algunas áreas, causando adelgazamiento local de los lentes de agua dulce. El abastecimiento de agua del acueducto en la Isla St. George, representa entre 7% y 25% de la recarga natural; por otro lado se necesitan cantidades mayores de recarga para simular los lentes en la Isla St. George que en la Isla Dog. En ambas islas, las tasas de erosión costera son tan rápidas, que las lentes de agua dulce podrían no estar en equilibrio con las condiciones actuales de frontera.

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Résumé La morphologie des lentilles deau douce des îles de Dog et de St. George, situés dans le district côtier de Florida-Etats Unis est contrôlé dans une mesure variable par des facteurs naturelles et humaines. Les modèles découlement à densité variable des eaux souterraines confirment que la variation spatiale de la recharge peut expliquer les asymétries observées des lentilles des cettes îles. La profondeur des lentilles ne présente pas des variations saisonnières importantes. Les activités humaines ont modifié la recharge dans certaines zones en amincissant localement les lentilles deau douce. Lalimentation en eaux de lîle de St. George représente 7–25% de la recharge naturelle; pour simuler les lentilles de lîle de Dog il a été nécessaire dintroduire des valeurs plus élevées de la recharge par rapport aux ceux utilisés pour lîle de St. George. Pour les deux îles lérosion côtière est assez rapide ainsi que les lentilles de eau douce ne sont pas en équilibre avec les conditions à la frontière.

     

赣南红壤丘陵崩岗侵蚀区表土孢粉组合及其生态指示意义

以赣南红壤崩岗侵蚀区野外调研孢粉资料为基础,分析了8个表土样品。结果发现:赣南红壤崩岗侵蚀区表土样品孢粉种属类型丰富,共鉴定出131种,统计有效孢粉2 694粒;表土孢粉组合为乔木、灌木、草本、蕨类和苔藓植物,其中乔木和蕨类植物的孢粉占优势,平均分别为48.49%和37.10%,灌木和草本花粉含量较低,平均为3.00%和8.43%。乔木植物中的马尾松(Pinus massoniana)平均浓度为28.0%,蕨类植物中里白厥(Hicriopterisglauca)平均浓度为26.09%,均具有超代表性;植物花粉亚热带特征明显;不同母岩崩岗侵蚀区优势科属种方面存在一定的差异;孢粉组合反映出马尾松、里白蕨对红壤崩岗生态环境的适应性和代表性。该研究为今后在这一地区开展第四纪古植被、古气候和古环境等研究提供参考性依据,同时也为南方崩岗治理筛选先锋植物提供参考。     

基于GIS的小流域土壤侵蚀与产沙的简化模拟

将泥沙输移能力公式与USLE公式相结合,建立了一个简化的分布式小流域产沙模型,并将其应用于川中丘陵区小流域的土壤侵蚀与泥沙输移的空间分布模拟。得到的主要结论:1.该模型适用于川中丘陵区小流域产沙的模拟;2.魏城河流域1980—1987年8 a平均土壤侵蚀量为16.8×104t,侵蚀模数为675.8 t/(km2.a),模拟得到的输沙模数为238.6 t/(km2.a),泥沙输移比为0.35;3.魏城河流域主要以微度侵蚀为主,占到全流域总面积的68%,强度侵蚀占流域面积的1%,主要分布在坡度较陡的流域边缘地带;4.相对其他因子,降雨与坡度对该流域侵蚀产沙的影响更为突出。     

流域侵蚀产沙人类活动影响指数研究——以长江上游为例

流域产沙是土壤侵蚀的重要反映, 受降雨等自然要素和人类活动的共同作用。采用退 耦理论的思想和差分方法推导出流域侵蚀产沙人类活动影响指数的简易估算方法, 并对长江 上游的金沙江、乌江、嘉陵江、岷江分别计算人类活动总体贡献率。结果表明, 各流域人类 活动对侵蚀产沙变化的贡献率达72%～97%,总体上属于抑制侵蚀的正向活动。长江上游输 沙量呈阶段梯级变化, 根据流域侵蚀产沙人类活动影响指数的距平累积变化的突变特征将 1955～2009年划分为5个阶段并分析了每个阶段人类活动的主要特点及其对侵蚀产沙的影响。 其中, 20世纪80年代中期以前河流输沙量较大, 主要与“一五”、“大炼钢铁”、“三线建设”、 农村改革前期不稳定因素等密切相关, 而70年代河流输沙量较小是受当时大搞农田基本建设 和采取“挑沙面土”、“边沟背沟”等传统水土保持措施的影响, 80年代中期后河流输沙量明 显减少, 主要受社会经济稳定有序发展、水保工程的实施及大兴水库建设等影响。     

Palaeosurfaces and major valleys in the area of the Kjǿlen Mountains,southern Norway - consequences of uplift and climatic change

Protected area management in Norway is undergoing institutional changes with the implementation of management models aimed at increased public participation. At the same time tourism enterprises are increasing in number within the protected areas. Greater levels of interaction with stakeholders place new demands on lead institutions in terms of communication, transparency, involvement, and power sharing. A governance perspective was used to examine some facets of the interaction between a local council managing a national park in Norway and tourism companies using the park for their operations. The main objective was to assess how the tourism sector perceives the cooperation and interface with the management institution. Semi-structured interviews were used, together with a framework of United Nations Development Programme principles of good governance: legitimacy and voice, direction, performance, accountability, and fairness. The results showed rather negative evaluations by the tourism sector, and operators expressed views, implying that the current management model fails to achieve most of the principles of good governance. Although based on a one-sided view by one group of stakeholders, the study suggests that lack of access to important processes and decisions, perceived bias towards traditional conservation, neglect of cultural heritage, and undue restrictions on access could have serious implications for developing an effective management model.     

西北风沙起蚀观测试验及其研究进展

简要阐述了国家自然科学基金“西北沙漠地表沙粒运移特性及动力热力参数研究”支持的“我国西北三大沙漠地表风蚀起沙观测试验”的科学意义、试验方案和科学目标,总结了该试验在前期取得的部分研究进展和研究成果,概括叙述了该项目在地表沙粒跃移特征、起沙风速、沙尘通量等方面的重要发现和一些新的认识。最后,提出并讨论了在沙漠风蚀起沙观测试验方面需要进一步研究和思考的一些重要问题。     

Quaternary uplift of northern England

Upland flats, attributable to erosion, have long been recognised in the landscape of the Lake District region of NW England, at altitudes of up to ~ 800 m O.D. Extrapolation using uplift rates derived from dated Pleistocene sites (karstic caves and other features) in the adjacent Pennine uplands suggests that if this succession of flats formed close to sea-level they date from the Middle Pliocene onwards, indicating a subsequent time-averaged uplift rate of almost 0.3 mm a^− 1. Numerical modelling indicates that erosion of surrounding areas at a typical rate of 0.2 mm a^− 1 since 3.1 Ma could have caused this uplift, as well as constraining the local effective viscosity of the lower crust as ~ 4 × 10¹⁸ Pa s and the typical local Moho temperature as ~ 650 °C. It is thus feasible that most of the topography of northern England has developed since the Middle Pliocene, as a consequence of coupling between erosion and the resulting induced flow in the lower continental crust. The much faster vertical crustal motions indicated in this part of northern England, compared with SE England, are thus mainly a consequence of much greater mobility of the lower crust in the north, due to its younger thermal age and the heating effect of radioactive Palaeozoic granites. Uplift of this magnitude, which has previously gone unrecognised, may have affected post-Pliocene global climate.     

Insects as zoogeomorphic agents: an extended review

Insects are the largest and most diverse group of living organisms on Earth, playing a critical but underestimated role as agents of geomorphic change. Burrowing insects create micro-scale landforms such as subterranean tunnels and surface mounds and, by this way, exert an influence on hydrology, soil erosion and sediment transfer at a wider landscape scale. However, social insects represented by ants and termites were the main taxa studied as geomorphic agents and ecosystem engineers. This article proposes an extended and critical literature review of insects as zoogeomorphic agents, with reference to various taxonomic orders and families of insects having a burrowing behaviour. It provides a large overview of their primary and secondary impacts on Earth surface systems, both supported by naturalistic evidence and available quantitative data. Some evolutionary insights are discussed based on fossil evidence of geomorphic work by insects and, at finer temporal scale, on recent advances in radiometric and luminescence dating of insect mounds. Finally, this article explores the fruitful links between geomorphology and entomology, and suggests several research perspectives in order to develop an integrated understanding of the importance of insects in Earth surface processes and landforms. © 2020 John Wiley & Sons, Ltd.