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441.
通过剖析传统的敏感性分析法,提出交叉敏感性概念,评价生态服务价值对土地利用类型转换的响应性。以克里雅绿洲为研究区域,以1991、2002 和2011 年三期遥感影像数据为基本信息源,运用交叉敏感性分析,计算生态系统服务价值对土地利用类型转换的敏感性,确定生态系统日趋敏感的土地利用变化过程,为土地管理对策提供参考依据。研究结果表明:20 a来,克里雅绿洲生态服务价值较敏感的土地利用转换类型相对稳定,主要集中在湿地和水体向荒漠和低覆盖度草地的转换;与1991 和2011 年相比,2002 年的交叉敏感性系数普遍上升,这主要是因为湿地、水体面积的减少加剧了研究区的生态脆弱性,从而表现出更大的敏感性;湿地和水体向耕地转换的交叉敏感性一直处于上升趋势,并不断接近于-1,表明生态服务价值对高强度的人为活动变得越来越敏感,从而警示地方管理部门采取必要措施制止此种转换的持续。  相似文献   
442.
Abstract: Conservation prioritization usually focuses on conservation of rare species or biodiversity, rather than ecological processes. This is partially due to a lack of informative indicators of ecosystem function. Biological soil crusts (BSCs) trap and retain soil and water resources in arid ecosystems and function as major carbon and nitrogen fixers; thus, they may be informative indicators of ecosystem function. We created spatial models of multiple indicators of the diversity and function of BSCs (species richness, evenness, functional diversity, functional redundancy, number of rare species, number of habitat specialists, nitrogen and carbon fixation indices, soil stabilization, and surface roughening) for the 800,000‐ha Grand Staircase‐Escalante National Monument (Utah, U.S.A.). We then combined the indicators into a single BSC function map and a single BSC biodiversity map (2 alternative types of conservation value) with an unweighted averaging procedure and a weighted procedure derived from validations performance. We also modeled potential degradation with data from a rangeland assessment survey. To determine which areas on the landscape were the highest conservation priorities, we overlaid the function‐ and diversity‐based conservation‐value layers on the potential degradation layer. Different methods for ascribing conservation‐value and conservation‐priority layers all yielded strikingly similar results (r= 0.89–0.99), which suggests that in this case biodiversity and function can be conserved simultaneously. We believe BSCs can be used as indicators of ecosystem function in concert with other indicators (such as plant‐community properties) and that such information can be used to prioritize conservation effort in drylands.  相似文献   
443.
Extensive green areas generate a recognizable green identity of Ljubljana. Due to the challenges of climate change and urbanization the city's spatial policy highlights revitalization of degraded urban areas, preserving the quality and scope of the existing green network and the protection of multifunctional natural areas surrounding the city. Article describes the project of Rakova Jelša Park as a good example of these policies. With an NGO initiative a former degraded area with illegal dumping and non-indigenous vegetation was transformed into recreational park with increased biocultural diversity. Important lesson of the project is that opening up space for public use not only prevents degradation, but also improves the quality of urban ecosystems. One of the challenges for the city's future sustainable ecosystem development will be a more active cooperation with its citizens in the green infrastructure policy and later also a partial transfer of responsibility for green areas to them.  相似文献   
444.
Ecosystem approach, a new comprehensive approach to the conservation and management of natural resources, has received universal concern and approval in the world, and it requires the application of the eco-compensation mechanism. Some basic ideas for establishing the marine eco-compensation mechanism are: payers and payees can be identified through analyzing marine ecosystem service changes and impacts on the stakeholders; financial transfer payment and environmental taxes and fees can be used as the main channels for compensation; payment standard can be set up by following the principle of a compromise between calculated theoretic results and “price bargaining”. Focusing on the key human impact on marine ecosystem in Bohai Sea, some preliminary ides on eco-compensation application are given: reform the ongoing charge system of pollutant discharge and enhance its incentives to reduce land pollutants; implement eco-compensation for freshwater demand between Bohai Sea and the river basins for the purpose of increasing freshwater inflow; popularize and strengthen the existing eco-compensation on fishery resources management, and implement the charge system of eco-compensation on reclamation from the sea for land construction.  相似文献   
445.
446.
ABSTRACT: The quality of the U.S. Army Corps of Engineers' (Corps) total dissolved gas (TDG) data base for the 1995 spring spill season was reviewed to determine the value of this information in real-time management decisions regarding river operations. We concluded that problems in transmitting, archiving, correcting and interpreting the records constitute significant sources of data anomalies that affect the accuracy and reliability of information necessary to manage spill and TDG in the Columbia and Snake rivers. The data base that was reviewed covers 25 selected Columbia and Snake river stations, and includes real-time TDG data needed to regulate spill operations to maintain gas levels within state water quality standards and to monitor effects on fish and aquatic life during the salmon migration season. A wide range of anomalies (daily averages missing or in error or based on incomplete records) was detected in more than one-third (37 percent) of the Corps' gas data base. Extreme anomalies (daily averages including errors and discontinuities for more than eight hours in a day) were found in 16 percent of the data base. The Fish Passage Center, also reviewed the Corps' data and reported an overall 33 percent incidence of anomalous days. Despite arriving at similar findings about the Corps' data base, we detected a 28 percent discrepancy in the type of data anomalies between our analyses. Real. time improvements in the quality of the dissolved gas data base are necessary to provide managers with a reliable product from this monitoring effort.  相似文献   
447.
黑龙滩水库水体生态系统酶活力及其生态学意义研究   总被引:3,自引:0,他引:3  
本文黑龙滩水库水体生态系统中脲酶与磷酸酶活力及其与多种水质参数之间的关系进行了研究,结果表明:(1)酶活力与水质,水温变化呈出现一致的动态变化规律。(2)黑龙滩水库水体中脲酶来源与水生生物关系不大,而磷酸酶主要来自浮游植物和水生细菌。(3)水体中脲酶活力受水中总氮浓度瓣影响,而磷酸酶活力不受水中磷酸盐的抑制。  相似文献   
448.
ABSTRACT: A scheme is outlined to classify watersheds as ecosystems, based on their natural attributes. Two physical factors of the environment, climate and geology, are selected as state factors. Climate is the master factor that supplies energy and water to all ecosystems; geologic structure supplies the materal from which the forces of climate carve landforms to establish ecosystems. At the next lower level, soil and vegetation interact in a succession of transactions to produce a mosaic of tesseras within each watershed. It is these interacting tesseras that moderate climate and store energy within the ecosystem that influences the embedded stream. At the bottom of the scale is the stream with its passive role and inability to interact with the higher factors of the ecosystem. Thus, we have a controlling force consisting of two elements (climate and geology), a reacting force (soil and vegetation) that responds by circular conditioning to controlling forces, and at the lowest level, the stream which responds to all factors of the living system within its watershed.  相似文献   
449.
ABSTRACT: H2SO4 (sulfuric acid) is formed by a chemical process that occurs in unreclaimed coal mines. The highly toxic acid then flows into the lower swamp areas where it causes considerable damage to the ecosystem. The major effect of the acid is the mass destruction of thousands of trees and various other phreatophytic plants. The contamination is so serious that most of the wildlife has migrated out of the affected area of the swamp in order to survive. Certain geological features such as coal bearing monadanocks make the area somewhat sensitive to mining activities and related geologic hazards. New methods of mine acid abatement make the concept of mass reclamation more realistic than at any time in the past. The constant annihilation of swamp life and processes emphasizes the urgent need for reclamation of the swamp.  相似文献   
450.
Naturalness In Biological Conservation   总被引:1,自引:0,他引:1  
Conservation scientists are arguing whether naturalness provides a reasonable imperative for conservation. To clarify this debate and the interpretation of the term natural, I analyze three management strategies – ecosystem preservation, ecosystem restoration, and ecosystem engineering – with respect to the naturalness of their outcomes. This analysis consists in two parts. First, the ambiguous term natural is defined in a variety of ways, including (1) naturalness as that which is part of nature, (2) naturalness as a contrast to artifactuality, (3) naturalness as an historical independence from human actions, and (4) naturalness as possession of certain properties. After that, I analyze the different conceptions with respect to their implications for the three management strategies. The main conclusion is that there exists no single conception of naturalness that could distinguish between the outcomes of the three management methods. Therefore, as long as the outcomes of the different methods are regarded as being of a different value in conservation, we should either abandon the idea of naturalness as the guiding concept in conservation or use the term natural only in the ways that take both its historical and feature dependent meanings into consideration.  相似文献   
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