首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到5条相似文献,搜索用时 5 毫秒
1.
In small populations the lack of mating individuals may cause a reduction in reproductive potential which can restrict population expansion or cause further population declines. This is especially true in outcrossing monoecious and self-incompatible dioecious plant species. Principles of pollen dispersal suggest that many small to medium size population reserves of round shape will maximize the pollen interaction within and between island reserves. Diverse and low-density ecosystems require more total area in reserves than low-diversity and high-density ecosystems.  相似文献   

2.
The primary role of remote sensing in land management and planning has been to provide information concerning the physical characteristics of the land which influence the management of individual land parcels or the allocation of lands to various uses These physical characteristics have typically been assessed through aerial photography, which is used to develop resource maps and to monitor changing environmental conditions These uses are well developed and currently well integrated into the planning infrastructure at local, state, and federal levels in the United States.Many newly emerging uses of remote sensing involve digital images which are collected, stored, and processed automatically by electromechanical scanning devices and electronic computers Some scanning devices operate from aircraft or spacecraft to scan ground scenes directly; others scan conventional aerial transparencies to yield digital images. Digital imagery offers the potential for computer-based automated map production, a process that can significantly increase the amount and timeliness of information available to land managers and planners.Future uses of remote sensing in land planning and management will involve geographic information systems, which store resource information in a geocoded format. Geographic information systems allow the automated integration of disparate types of resource data through various types of spatial models so that with accompanying sample ground data, information in the form of thematic maps and/ or aerially aggregated statistics can be produced Key issues confronting the development and integration of geographic information systems into planning pathways are restoration and rectification of digital images, automated techniques for combining both quantitative and qualitative types of data in information-extracting procedures, and the compatibility of alternative data storage modes  相似文献   

3.
This paper provides an overview of the environmental impact of mining on viable future land use and underlines the imperative of improved environmental management and closure planning. It argues that pollution prevention, through planning for closure, can lead to cost-effective strategies for sustainable minerals development and viable future land use. This seems to be most true for greenfield sites since, generally, the earlier closure planning and pollution prevention is built into a project, the more cost-effective and environmentally benign closure will be. Further, for greenfield sites, pollution prevention techniques can be employed from the outset, at the stages of exploration and mine development, and then monitored and improved through the operation stage to closure, and can be kept in place to manage future land use.
The paper discusses how global changes in the industry, following the liberalisation of investment regimes, and mergers and strategic alliances between key firms, has, by virtue of the diffusion of new technology, led to further opportunities to prevent pollution and optimise future land use through planning for closure from the outset. The objectives and components of closure plans are also reviewed as the paper draws on case studies to highlight some of the possible constraints and challenges to pollution prevention that may be faced at the level of both public policy and corporate strategy. The article concludes by suggesting a forward-looking approach to integrated environmental management and viable future land-use planning based on a dynamic model for environmental management.  相似文献   

4.
The environmental planning and management of the Assarawat highlands of south-western Saudi Arabia are currently confronted by difficult problems. Deforestation is caused either by natural or intentional forces. Natural factors are limited to lightning fire and drought, while intentional forces include vandalism caused by the burning or cutting of preserved forests. Such vandalism continues despite the tremendous efforts of afforestation and preservation by several government agencies, especially the Ministry of Agriculture and Water, the National Commission for Wildlife Conservation and Development and by the municipalities of the cities and towns in the region. For centuries, local inhabitants of the Assarawat highlands have successfully established environmental planning and management strategies which balanced the settlements' growth and natural resource uses according to Islamic laws, and the tribal self-government of each settlement and tribal region. Following the establishment of the Kingdom of Saudi Arabia in 1932, the land management system started to change from tribal-based, where every tribe used to manage its local territory, to State authority. The creation of the State witnessed the unification of various fragmented tribes of Saudi Arabia into one government. This meant that environmental planning and management moved from local/regional towards a national control. This investigation proposes that the local/regional planning and management practised by the tribes could be viably utilized today. As in the past, the implementation of these practices could protect the natural environment of the locality and region and regularize their exploitation rationally, as long as vernacular people implement them. Today environmental planning and management need to be based on strategies of local requirements that enable the indigenous people to plan and manage the use of the resources.  相似文献   

5.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号