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951.
Assessments of risk to biodiversity often rely on spatial distributions of species and ecosystems. Range‐size metrics used extensively in these assessments, such as area of occupancy (AOO), are sensitive to measurement scale, prompting proposals to measure them at finer scales or at different scales based on the shape of the distribution or ecological characteristics of the biota. Despite its dominant role in red‐list assessments for decades, appropriate spatial scales of AOO for predicting risks of species’ extinction or ecosystem collapse remain untested and contentious. There are no quantitative evaluations of the scale‐sensitivity of AOO as a predictor of risks, the relationship between optimal AOO scale and threat scale, or the effect of grid uncertainty. We used stochastic simulation models to explore risks to ecosystems and species with clustered, dispersed, and linear distribution patterns subject to regimes of threat events with different frequency and spatial extent. Area of occupancy was an accurate predictor of risk (0.81<|r|<0.98) and performed optimally when measured with grid cells 0.1–1.0 times the largest plausible area threatened by an event. Contrary to previous assertions, estimates of AOO at these relatively coarse scales were better predictors of risk than finer‐scale estimates of AOO (e.g., when measurement cells are <1% of the area of the largest threat). The optimal scale depended on the spatial scales of threats more than the shape or size of biotic distributions. Although we found appreciable potential for grid‐measurement errors, current IUCN guidelines for estimating AOO neutralize geometric uncertainty and incorporate effective scaling procedures for assessing risks posed by landscape‐scale threats to species and ecosystems.  相似文献   
952.
Despite much discussion about the utility of remote sensing for effective conservation, the inclusion of these technologies in species recovery plans remains largely anecdotal. We developed a modeling approach for the integration of local, spatially measured ecosystem functional dynamics into a species distribution modeling (SDM) framework in which other ecologically relevant factors are modeled separately at broad scales. To illustrate the approach, we incorporated intraseasonal water-vegetation dynamics into a cross-scale SDM for the Common Snipe (Gallinago gallinago), which is highly dependent on water and vegetation dynamics. The Common Snipe is an Iberian grassland waterbird characteristic of European agricultural meadows and a member of one of the most threatened bird guilds. The intraseasonal dynamics of water content of vegetation were measured using the standard deviation of the normalized difference water index time series computed from bimonthly images of the Sentinel-2 satellite. The recovery plan for the Common Snipe in Galicia (northwestern Iberian Peninsula) provided an opportunity to apply our modeling framework. Model accuracy in predicting the species’ distribution at a regional scale (resulting from integration of downscaled climate projections with regional habitat–topographic suitability models) was very high (area under the curve [AUC] of 0.981 and Boyce's index of 0.971). Local water-vegetation dynamic models, based exclusively on Sentinel-2 imagery, were good predictors (AUC of 0.849 and Boyce's index of 0.976). The predictive power improved (AUC of 0.92 and Boyce's index of 0.98) when local model predictions were restricted to areas identified by the continental and regional models as priorities for conservation. Our models also performed well (AUC of 0.90 and Boyce's index of 0.93) when projected to updated water-vegetation conditions. Our modeling framework enabled incorporation of key ecosystem processes closely related to water and carbon cycles while accounting for other factors ecologically relevant to endangered grassland waterbirds across different scales, allowed identification of priority areas for conservation, and provided an opportunity for cost-effective recovery planning by monitoring management effectiveness from space.  相似文献   
953.
基于FLAC3D有限差分软件对开挖深度、侧压力系数、断面形状等多因素影响下的巷道变形参数进行正交试验,根据正交试验分析结果,分别选取同一深度条件下的圆形、马蹄形、直墙拱形、矩形巷道进行模拟试验并以圆形巷道作为典型断面,对不同深度下的巷道变形特征进行模拟试验。研究结果表明:开挖深度对巷道开挖后的应力差变化影响明显,断面形状对巷道围岩内的塑性区深度和具有显著影响;巷道开挖后的塑性区深度和随形状指数增加而呈线性增长趋势,圆形巷道的塑性区深度和最小,矩形最大;应力差随着巷道开挖深度的增加呈线性增加,深部开采应重视巷道内的应力分布情况。  相似文献   
954.
The numerous formulated products which are introduced to the market consist of chemical ingredients that may cause various safety and health hazards to the consumers. Therefore, it is extremely important to practice a systematic methodology to formulate products with acceptable safety and health performances. This work presents an index-based methodology to assess the safety and health hazards of the ingredients during the early formulation stage of product design. Hence, new inherent safety and health sub-indexes are introduced to improve the current safety and health hazards that are needed in formulated product design. The inherent safety and health sub-indexes are assigned with scores based on the degree of potential hazards. A higher score indicates a higher safety risk or severe health effect, and vice versa. The proposed methodology will greatly assist the users to identify the adverse safety and health effects caused by the ingredients. Hence, it is pivotal to eliminate or reduce the safety and health impacts from product usage. A case study on common ingredients used in the formulation of paint is presented on this study to describe the proposed method.  相似文献   
955.
以上海市青浦区为研究区域,基于ETM遥感影像数据和GIS技术,采用优势规则栅格聚合方法,对分类的ETM数据进行了粒度变换。以景观格局分析程序Fragstats3.3为分析工具,从景观类型水平和景观水平上研究了景观格局的空间粒度效应。研究结果表明:(1)不同的景观类型、不同的景观特征指数对粒度响应存在差异:居住景观和道路景观是对粒度响应最敏感的两种景观类型;形状指数、聚集度指数、斑块数量指数对粒度响应的敏感程度较高,多样性指数、均匀度指数、景观面积比例指数、分维数对粒度响应的敏感程度较低;此外,还发现优势景观随着粒度增加面积增大,形状规则的景观对粒度响应敏感程度低。(2)景观指数的粒度响应曲线存在尺度转折点,且多出现在40、60、80、120m,其中第一尺度区域多为20~40m或20~60m。第一尺度域是选择适宜粒度的较好取值范围,所以本研究中所用景观类型图进行景观指数计算的适宜粒度范围为30-40m。(3)研究发现由不同指数表征相同的生态现象可能会出现相反的粒度效应,在一定程度上体现了景观指数量化景观格局的局限性。  相似文献   
956.
边际效应理论及其增值效应是现代生态科学很重要的一个原理.我国是典型的经济发展不平衡的国家,长期的区域非均衡战略在全国范围内形成了四大区域板块.面对着东部的开放崛起,西部大开发和东北老工业基地的改造,"谨防中部凹陷,促进中部崛起"作为一个区域协调发展的重大命题,被提到了国家层面上.中部板块由于地理区位与经济发展水平均居于我国的中间位置,因此具有明显的过渡性.作者试图通过运用生态学上的边际效应理论,分析中部区域板块内部以及板块之间的区域经济协调发展机制,来促进中部区域板块经济的协调发展.  相似文献   
957.
本文从高科技发展角度论述了高科技发展与环境承载力之间的关系,并对已有的环境承载力理论做了补充和改进,使之更能体现可持续发展的新发展观。本文还对不同国家在处理高科技发展与可持续发展关系的途径做了概要阐释。最后指出,高科技污染也是一个不容忽视的问题。  相似文献   
958.
环境投资占国民生产总值的比例是国际上普遍采用的衡量和评价各国环境与经济持续发展程度的重要指标,为控制我国日趋严重的环境形势,应加强对考核指标的研究,拓宽筹集资金的渠道,扩大环境投资的比例。  相似文献   
959.
城市可持续发展的综合评价   总被引:55,自引:5,他引:50  
本文从可持续发展概念出发,建立了城市的发展持续度、发展协调度和发展水平综合评价的指标体系,应用模糊综合评价法和层次分析法,对乌鲁木齐市、新疆、全国城市可持续发展进行了定量评价,并确定了可持续发展目标伍,为城市可持续发展评价理论研究提供了科学依据。  相似文献   
960.
中国可持续发展指标体系建立的原则及结构   总被引:29,自引:1,他引:28  
本文从中国的现实情况出发,借鉴了国外研究可持续发展指标体系的经验,提出了中国可持续发展指标体系的建立原则和结构。  相似文献   
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