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991.
The biophysical environment of rangelands in the arid and semi-arid lowland parts of Africa is customarily viewed as a homogenous entity. Such notion has encouraged employing a blanket management approach. However, there are perceptible variations within them which necessitate site-specific range management. This study has attempted to identify the variability of soil and forage attributes and assess the existing management practices of those resources in the Baro River plain, Ethiopia. Sample transects, representing pre- and post-fire conditions, were used to collect composite soil samples and vegetation attributes. Alongside the physical survey, a household survey was undertaken to validate the laboratory-generated information. The result showed significant differences of soil and forage attributes among different management regimes, distances from river course and dominant cover types. In general, the distribution of soil nutrients showed a 'distance decay effect', while the distribution of pH showed the reverse pattern. Application of heavy fire load and congested grazing are the principal range management related factors. About 80 per cent of sample pastoralists employ heavy fire without due consideration for the sustainability of the range resource and without considering the local variability. Recognition of site-specific information is the key to effective management of range resources in the study area. 相似文献
992.
Rebecca Jackson 《The Australian geographer》2008,39(4):495-519
Rottnest Island is a popular holiday destination offshore from Perth, the capital city of Western Australia. Rottnest (or Rotto) attracts approximately 500 000 visitors annually. The island is managed by a statutory government authority, the Rottnest Island Authority (RIA), for the purposes of providing recreation and holiday facilities and services, and protecting its natural and cultural values. While there are advantages in management by one body, there appears to be a conflict in managing both the tourism business and the environment, largely as a result of funding issues. While further tourism development would boost the RIA's self-funded operating budget, increased pressures may compromise the island environment and the Rottnest ethos, which revolves around a relaxed and casual social ambiance. The RIA aims to develop Rottnest as a model for sustainability, but are dilemmas surrounding economic sustainability potentially risking the island's environmental and social sustainability? This paper concludes that in the pursuit of economic returns from tourism, Rottnest Island's environmental and social values face an uncertain future. 相似文献
993.
WILLIAM JAMES SMITH JR 《The Geographical journal》2008,174(3):251-268
Many least-wealthy, rural, remote and resource-poor small island communities are unlikely to benefit from high-profile global water improvement initiatives. Their small landmasses, geologic composition, geography, social and technological isolation, colonial history, and weak educational and financial resources constitute significant barriers to improving access to safe drinking water. This paper discusses the relatively unique position of such island societies in the international community, providing a case study of the Federated States of Micronesia that integrates data and information pertaining to water resources management and governance, spanning from the island village to national scale. A vision is offered regarding the interaction between small island human and biophysical water systems, manifesting ways to pursue water resource development to improve public health which are constructed to be economically, physically and culturally sustainable. 相似文献
994.
Alan B. Dixon 《Singapore journal of tropical geography》2008,29(3):341-356
Local community based institutions that coordinate the management of natural resources have been linked to socioecological resilience, adaptation and sustainability within rural livelihood systems throughout the developing world. The resilience and sustainability of related local institutions, however, is influenced by their relationship with external actors and institutions, particularly in facilitating, supporting or hindering local institutional arrangements. From this standpoint, this paper examines the case of local community based institutions involved in wetland management in western Ethiopia. Drawing upon the findings of participatory fieldwork undertaken in eight wetland‐using communities of Illubabor and Western Wellega zones in Oromia Region it is argued that although local institutions do play a key role in coordinating wetland management and sustaining the benefits from wetlands, the sustainability and resilience of the institutions themselves is threatened by a range of factors. Despite their grassroots nature, their effectiveness is influenced by their reliance on local government backstopping that appears to have diminished in recent years, as well as a perceived lack of local government support for collective action over individual rights. 相似文献
995.
以福州滨江城区台江区为例,探讨历史时期、建国时期和现今时期3个演化阶段“涉水”地名文化景观的变化与城市演进的关系.研究结果表明,从历史时期至今,计有消失地名109个,新增地名78个和保留地名30个,消失比率约为50%;反映商业经济业态、方言特色和居住环境的定名方式也随之消失,取而代之的是类似的“城市化”地名,这亦是滨江地域文化的流失.现今“涉水”地名文化景观分别以保留地名与内河体系为增长“极核”和“扩展轴”,两者的叠加效应致使其重心向东迁移.现今地名加快的更新过程折射出城市演进和扩展速度超过建国时期和历史 相似文献
996.
997.
998.
Channelisation measures taken halfway the 20th century have had destructive consequences for the diversity of the ecology in the majority of the lowland streams in countries such as the Netherlands. Re-meandering is the common practice in restoring these lowland streams. Three reconstructed streams were monitored during the initial two years after construction of a new channel. The monitoring program included morphological surveys, sediment sampling, habitat pattern surveys, and discharge and water level measurements. Adjustments of the longitudinal bed profile formed the main morphological response. These adjustments were most likely caused by a lack of longitudinal connectivity of the streams as a whole, interrupting transport of sediment at locations of weirs and culverts. Bank erosion was observed only in a limited number of channel bends, and was often related to floodplain heterogeneity. Longitudinal channel bed adjustments and bank erosion were mainly caused by exogenous influences. In channel bends, the cross-sectional shape transformed from trapezoidal to the typical asymmetrical shape as found in meandering rivers. This behaviour can be attributed to an autogenous response to the prevailing flow conditions. Due to the prevailing fine sediment characteristics, bed material is readily set in motion and is being transported during the entire year. The existing design principles fail to address the initial morphological development after reconstruction. An evaluation of pre-set targets to realise water depth and flow velocity ranges shows the current procedures to be deficient. Based on this unfavourable evaluation, and the two-dimensional nature of habitat patterns needed to improve the conditions for stream organisms, we recommend to predict morphological developments as part of the design procedures for lowland stream restoration in the Netherlands. 相似文献
999.
Soil moisture dynamics across landscape types in an arid inland river basin of Northwest China 总被引:2,自引:0,他引:2 下载免费PDF全文
A combination of field measurements, continuous monitoring and numerical modelling was used to evaluate soil moisture regimes at four sites across a landscape gradient of the Heihe River Basin. Recorded data of precipitation, irrigation and floods were used to build the model, and an optimization technique was employed to calibrate the parameters. Based on the optimized parameters and estimates of future scenarios, the modelling structure was employed to predict the changes in the growing season soil moisture regimes due to climate change and intensive management. The results suggest that the upper‐reach Yeniugou and Xishui sites will become wetter because of alterations in the precipitation regime, and this trend could be strengthened by the expected amplified interannual variability. Precipitation features at middle‐reach Linze and lower‐reach Ejina, however, are not expected to change in the future. We assumed that a more water‐saving irrigation system will replace the current traditional one, and hence, the soil moisture probability density function at the Linze site would tend to be narrowed to ranges around either the wilting point or the point of incipient water stress, depending on how the intervention point and target level are settled. Ejina is expected to experience the most extreme ecological conversion effects in the future, and soil moisture would be more frequently recharged by water delivery. However, the soil moisture regime would not change much because of the poor water‐holding capacity and intensive evaporation. The revealed patterns and predicted shifts in soil moisture dynamics could provide a useful reference for identifying robust long‐term water resource management strategies for the Heihe River Basin. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
1000.
提出了广东省不动产登记信息管理基础平台的技术框架,重点对应用系统的体系构成及主要功能、数据库的逻辑结构及物理存储进行了总体设计,通过采用ESB、MyCAT分布式数据库中间件、OLAP多维分析等关键技术实现了平台的开发和应用,为广东省全面开展不动产登记工作提供了重要的技术保障。 相似文献