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981.
James G. Titus 《Environmental management》1991,15(1):39-58
Climatologists generally expect an anthropogenic global warming that could raise sea level 30–150 cm in the next century and
more thereafter. One of the impacts would be the loss of coastal wetlands. Although the inundation of adjacent dryland would
enable new wetlands to form, much of this land is or will soon be developed. If developed areas are protected, wetlands will
be squeezed between an advancing sea and the land being protected, which has already happened in China and the Netherlands,
where people have built dikes for centuries.
Unlike those countries, the United States has enough land to accommodate the landward migration of wetlands; but governments
lack the funds to purchase all the coastal lowlands that might be inundated and the legal authority to prohibit their development.
We propose a third approach: allowing property owners to use coastal lowlands today as they choose, but setting up a legal
mechanism to ensure that the land is abandoned if and when sea level rises enough to inundate it. Although compensation may
be required, this approach would cost less than 1% as much as purchasing the land, and would be (1) economically efficient
by enabling real estate markets to incorporate expectations of future sea level rise; (2) constitutional by compensating property
owners; and (3) politically feasible by pleasing people who care about the long-term fate of the coastal environment without
disturbing people who either are unconcerned about the distant future or do not believe sea level will rise.
This article demonstrates that it would be irrational to delay policy formulation until sea level rise projections are more
precise. The cost will be small if we act now but great if we wait, and sea level is already rising along most coasts. The
US government should develop a strategy in the next three years.
The opinions expressed in this paper do not necessarily reflect the views of EPA and no official endorsement should be inferred. 相似文献
982.
从廉价高效的角度出发,介绍了三种去除污染水中N、P等营养物质的新技术:渗透性反应墙、人工湿地、水生附着物-鱼系统,并简要分析了其存在的问题及发展前景。希望通过这次探讨,为污染水净化提供一种新思路。 相似文献
983.
论湿地及其保护和利用——以洪湖湿地为例 总被引:17,自引:0,他引:17
本文阐述了湿地的定义,并以洪湖为例,从水文、土壤、生物组成和系统的功能等方面论述了湿地生态系统的特征,进而提出湿地保护和利用问题。文章最后指出:只有对湿地进行充分的保护,才能使其持续地为人类提供财富。 相似文献
984.
Land uses such as forestry and agriculture are presumed to degrade the biodiversity of riparian wetlands in the northern temperate regions of the United States. In order to improve land use decision making in this landscape, floral and faunal communities of 15 riparian wetlands associated with low-order streams were related to their surrounding land cover to establish which organismal groups are affected by anthropogenic disturbance and whether these impacts are scale-specific. Study sites were chosen to represent a gradient of disturbance. Vascular plants of wet meadow and shrub carr communities, aquatic macro-invertebrates, amphibians, fish and birds were surveyed, and total abundance, species richness and Shannon diversity were calculated. For each site, anthropogenic disturbances were evaluated at local and landscape scales (500, 1000, 2500 and 5000 m from the site and the site catchment) from field surveys and a geographic information system (GIS). Land use data were grouped into six general land use types: urban, cultivated, rangeland, forest, wetland and water. Shrub carr vegetation, bird and fish diversity and richness generally decrease with increasing cultivation in the landscape. Amphibian abundance decreases and fish abundance increases as the proportions of open water and rangeland increases; bird diversity and richness increase with forest and wetland extent in the landscape. Wet meadow vegetation, aquatic macro-invertebrates, amphibians and fish respond to local disturbances or environmental conditions. Shrub carr vegetation, amphibians and birds are influenced by land use at relatively small landscape scales (500 and 1000 m), and fish respond to land use at larger landscape scales (2500, 5000 m and the catchment). Effective conservation planning for these riparian wetlands requires assessment of multiple organismal groups, different types of disturbance and several spatial scales.1998 Academic Press 相似文献
985.
岩溶山区表土中~7Be、~(137)Cs、~(226)Ra和~(228)Ra的地球化学相分配及其侵蚀示踪意义 总被引:13,自引:1,他引:13
岩溶山区表土中7Be、137Cs、226Ra和228Ra地球化学相分配的实验研究表明,4种核素绝大部分(85%以上)存在于FeMn氧化物、有机质及残渣相中.它们在表土的迁移过程中具微粒迁移性,能较好地随土粒般运,可作为土粒侵蚀或沉积的示踪剂.但其微粒示踪类型又各具特征:7Be的化学形态与其季节性微粒迁移示踪一致;137Cs的化学形态适用于示踪土粒累计性迁移和沉积计年;226Ra和228Ra存在于粘土矿物结晶骨架中,在表土中主要以残渣相存在,由矿物化学风化作用而转入可溶解、可交换及碳酸盐结合相的比例很小,二者比活度的形态变化分异具有很好的侵蚀堆积示踪价值. 相似文献
986.
本文对达里诺尔湿地水环境1975年以来的监测数据进行了研究,结果表明:水环境以含盐量高、碱度强为主要化学特征。而且随着含势量和总碱度的增加,湿地水质有恶化趋势。 相似文献
987.
988.
989.
以滇池湿地景观设计为研究对象,介绍了水生植物在湿地景观设计中的作用和原则以及水生植物的选择、配置和生物浮岛技术的运用。 相似文献
990.