Vegetation change,erosion risk and land management on the Nullarbor Plain,Australia

 Arid karst landscapes that have been degraded by human activities provide a challenge for rehabilitation and an opportunity to test ideas about the stability and resilience of limestone ecosystems. The Nullarbor Plain is the largest arid karst area in Australia (220 000 km²) and is divided into extensive closed karstic depressions separated by low rocky ridges, while the dominant vegetation is chenopod shrubland. Since European settlement there has been considerable change in the vegetation, with significant reduction in shrub and grass cover over large areas of the plain. These changes are related to a state and transition model of vegetation dynamics which incorporates climatic variability, fire history and grazing pressure from sheep, kangaroos and rabbits. A partial sediment budget using ¹³⁷Cs inventories reveals local and regional patterns of soil redistribution within this arid karst landscape. Rehabilitation of eroded soil in pastoral lands has been accomplished at several sites but is labour intensive and vulnerable to climatic fluctuations. Given the low stock numbers, limited number of people involved, and poor economic returns, it would be sensible to make pastoral activities on the Nullarbor secondary to conservation priorities. This would necessitate a change in land ethic to stewardship, with emphasis on rehabilitation and control of feral animals. Management of increased numbers of visitors to the caves and karst also requires that resource inventories and management plans for each area be drawn up and used. Received: 1 June 1995 · Accepted: 4 December 1995     

Paleocollapse structure as a passageway for groundwater flow and contaminant transport

 Paleocollapse structure is a rock collapse, resulting from the failure in the geological history of the bedrock overlying karstified limestone. Depending on the present hydrogeological conditions within the area of paleocollapse and the internal properties of these structures, they can provide a means to facilitate groundwater flow and contaminant transport. Inactive paleocollapse structures can be reactivated by human activities such as dam construction, mining underground minerals, pumping groundwater, and development of landfills. They can also be reactivated by natural events such as earthquakes and neotectonic movements. In the mines of northern China, sudden inflow of karst water from Ordovician limestone into drifts and mining stopes through paleocollapse structures has caused significant economic loss. Water pumping tests and accompanied dye traces are effective approaches of locating water-conducting paleocollapse structures. Grouting is probably the best means of preventing them from becoming geohazards. Received: 26 November 1996 · Accepted: 17 June 1997     

Environmental and legal aspects of karst areas

 Environmental impacts on karst settings are common as they are more sensitive than those of other rock terrains. Regulatory procedures that are effective in other rock terrains are not necessarily applicable to karst settings. Development and exploitation by man that affect the karst hydrology regime can trigger catastrophic events and result in numerous legal actions where the effects of changes go beyond property boundaries. A great variety of regulations and examples of litigation exist for karst areas. Received: 25 October 1994 · Accepted: 17 October 1995     

北山戈壁荒漠景观1∶5万地球化学测量方法研究

通过在西北北山地区进行剖面和面积性方法试验,研制出了一套适合于西北荒漠戈壁景观条件的地球化学测量方法,即包括样品布局、采样密度、样品介质、样品粒级以及不同类型的地球化学测量方法技术。试验结果证实,每平方千米采集>20目的沟谷粗碎屑介质样品,能够圈定出清晰的矿化异常,而且异常元素组合齐全,指示意义明确,较准确地反映了矿体或矿化体的形态和延伸方向。同时辅助采集植物———红莎样品和<80目细粒级样品(提供热释汞分析),可以提取掩埋矿化体的信息。     

湖北省土壤侵蚀景观空间异质性及驱动因子分析

地域分异是地球表层大小不等、内部具有一定相似性地段之间的相互分化以及由此产生的差异。为了研究不同区位土壤侵蚀问题，从土壤生态景观及系统论出发，运用地质学、地理学、景观生态学、环境学的理论和研究方法，研究湖北省土壤侵蚀景观空间格局及其驱动因子，使土壤侵蚀问题研究提高到一个新的水平。湖北省土壤侵蚀景观具有南北分带、东西分区，为一不对称的断块一环组合，土壤流呈现向长江、江汉盆地中心轴带辐聚、单流向特点。景观空间异质性形成的首要驱动因子是大地构造背景，以房县一襄樊一广济断裂带为界，南北两侧地壳物质组成和构造发展史存在较明显的差异，现代气候带、降雨量、温热程度及土地利用等差异，造成了湖北省区域土壤地理、土壤生态的分异，形成湖北省土壤生态带、区具有南北分带，东西分区的宏观格局；其次大兴安岭一武陵山深部构造陡变带两侧新构造运动强度差异、大别造山带构造强烈隆升，导致土壤侵蚀强度的西强东弱、南北强中间弱的态势；成土母岩差异性决定了土壤可蚀性的多变；空间上“土壤侵蚀内城区”分布在湖北省的周边地区，经济贫困、管理落后，这一地区的经济水平与水土流失间形成“自反馈作用”，这一现象在我国水土保持、生态建设工作中应该引起重视。     

呼和浩特市城市边缘区景观格局动态变化研究

利用GIS技术对1987，2000年两期航空遥感影像进行空间叠加对比分析，从斑块及景观2个尺度对呼和浩特市城市边缘区景观格局变化进行了研究。结果表明：在斑块尺度上，边缘区两期景观结构均以农田景观为基质，研究期内，农田景观、草地景观等缓慢减少，建筑景观明显增多；在景观尺度上，边缘区景观多样性指数趋于增大，优势度指数趋于降低．景观组分趋于复杂化、破碎化和多元化。分析其影响因素可知：经济发展和城市化的加快、政策导向是变化的根本原因，人口的增加、土地利用方式的改变是变化的直接原因。     

Postglacial topographic evolution of glaciated valleys: a stochastic landscape evolution model

The retreat of valley glaciers has a dramatic effect on the stability of glaciated valleys and exerts a prolonged influence on the subsequent fluvial sediment transport regime. We have studied the evolution of an idealized glaciated valley during the period following retreat of ice using a numerical model. The model incorporates a stochastic process to represent deep‐seated landsliding, non‐linear diffusion to represent shallow landsliding and an approximation of the Bagnold relation to represent fluvial sediment transport. It was calibrated using field data from several recent surveys within British Columbia, Canada. We present ensemble model results and compare them with results from a deterministic linear‐diffusion model to show that explicit representation of large landslides is necessary to reproduce the morphology and channel network structure of a typical postglacial valley. Our model predicts a rapid rate of fluvial sediment transport following deglaciation with a subsequent gradual decline, similar to that inferred for Holocene time. We also describe how changes in the model parameters affect the estimated magnitude and duration of the paraglacial sediment pulse. Copyright © 2005 John Wiley & Sons, Ltd.     

森林沼泽景观区中大比例尺化探找矿工作方法的研究--记大梁金矿的发现

大梁金矿是通过森林沼泽景观区开展1：50000和1：25000地球化学测量及综合地质工作而发现的,证明采用的森林沼泽景观中大比例尺化探方法是行之有效的.     

华蓥山隧道岩溶发育强度垂直分带

论述了华蓥山隧道的岩溶发育特征,根据岩溶发育强度的划分依据和划分标准,结合岩溶发育的历史,采用类比判别法、主因素判别法和综合判别法对岩溶发育强度作了垂直分带,据此预测的溶洞规模与实际情况吻合。     

浅论安阳市传染病医院规划设计

以安阳市第五人民医院整体搬迁工程的设计为例,通过设计思路的详细介绍,阐述了传染病医院规划设计中注意到的几点问题。