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A number of mathematical models and solution techniques have been developed to design systems of reserve sites to protect species and their natural habitats. This paper presents two optimization models for obtaining ecological reserve systems that are spatially compact. Compact reserve systems will increase species persistence relative to more fragmented systems and can reduce the costs associated with reserve boundaries. These optimization models employ a hierarchical approach that incorporates both the boundary length of all clusters and the sum of within-cluster distances. Unlike previous approaches, we argue that measuring the distance between sites within clusters (and not between clusters) is more appropriate. Numerical experiments are conducted on synthetic grid systems and on a real-world hexagonal data set. These experiments confirm that the models produce reasonably compact clusters of reserve sites that respect species availability and budget constraints. Simplifications to the models are developed that significantly reduce the computational effort, while still identifying reasonable sets of reserve clusters. Sensitivity of the results to changes in model parameters (number of allowable sites, number of possible clusters, and rarity of species covered) is also explored.  相似文献   

3.
基于2018年高分系列遥感影像数据,提取山东省省级自然保护区人类土地利用活动信息,探讨人类活动对山东省省级自然保护区的影响。结果表明,自然保护区人类活动总面积占保护区总面积的22.2%,人类活动影响指数介于0~0.01368。不同类型的自然保护区人类活动面积不同,主要影响因子差异明显,森林生态类保护区以农业用地为主,内陆湿地类保护区以养殖场为主。内陆湿地类保护区是受到人类干扰程度最为严重的保护区类型,野生动物类保护区受到人类影响最小。  相似文献   

4.
大丰风电场建设对盐城自然保护区的生态影响分析   总被引:5,自引:0,他引:5       下载免费PDF全文
研究了大丰风电场一期、二期工程对盐城沿海湿地珍禽国家级自然保护区的生态影响.结果表明,在自然保护区实验区内建风电场会改变自然保护区生态结构和功能,使生物量减少,鸟类栖息地丧失,物种多样性下降,景观破碎化.提出了对策措施,以降低由于风电场的建设对自然保护区造成的生态影响.  相似文献   

5.
海南自然保护区遥感监测对森林资源监测、生态保护及热带亚热带地表研究具有重要意义。基于深度学习方法,针对海南省自然保护区大范围变化检测问题,对U-Net网络结构进行了改进,在每一个卷积层后加入标准化层,以跳线连接的形式将原有卷积模块改进为优化模块,同时在编码器底端添加金字塔池化模块以更好提取全局信息,形成了改进U-Net网络模型。模型训练采用基于交叉熵损失函数和广义骰子损失函数构建的联合损失函数,配合多种优化策略实现端到端的地物变化信息提取。该模型应用于公开数据集和研究构建的海南自然保护区数据集的变化检测任务,总体精度分别为97.21%(Kappa系数0.88)和95.12%(Kappa系数0.90),相比原始U-Net效果提升显著。  相似文献   

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This article examines instrumental climate records from a varietyof stations associated with the following Biosphere Reserves across Canada: (i) Waterton Lakes, (ii) Riding Mountain, (iii) Niagara Escarpment, (iv) Long Point, and (v) Kejimkujik (Candidate Biosphere Reserve). Annual series are generated fromdaily temperature and precipitation values. In addition, homogeneous data are used from other stations and regional records to supplement the records from the local biosphere stations. Long term trends are identified over the period of the instrumental record. In general, data from the interval 1900 to 1998 show cooler temperatures in the 1920's, warmingfrom the early 1940's into the early 1950's, cooling into the1970's, and subsequent warming. At many stations, 1998 is the warmest in the instrumental record. Comparisons with the regional data sets show good agreements between the temperatureseries. The 20th century warming is approximately 1.0 °C in the Riding Mountain area and 0.6 °Cin the Long Point, Niagara Escarpment, and Waterton Lakes areas.There has been slight cooling in the Kejimkujik area over the past half century. Precipitation data show increasing trends inthe Kejimkujik, Long Point, Niagara Escarpment, and Waterton Lakes areas with no long term trend in the Riding Mountain area. This work is part of the Canadian Biosphere Reserves Association (CBRA) Climate Change Initiative (CCI), designed to present climate change information to Biosphere Reserve communities to allow local organizations to understand climate change and adapt to potential impacts.  相似文献   

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激光雷达以其高精度的探测能力在大气污染研究中得到了广泛应用。由于生产厂家和反演算法等的差异,激光雷达观测数据的质量参差不齐。笔者利用2013年11月和2014年3月2种不同型号激光雷达(高频激光雷达和微脉冲激光雷达) 532 nm波段的气溶胶消光系数和气溶胶自动观测网(AERONET)光学厚度数据,对2部雷达在不同空气质量下的观测性能进行综合对比。结果表明:2部雷达在不同空气质量条件下探测效果不同,空气质量为优和良时,2部雷达的消光系数比较一致,偏差主要在1 km以下;随着污染加剧,2部雷达在1 km以下的偏差先减小后增大,1 km以上的偏差随高度增大。与AERONET的光学厚度相比,高频激光雷达在轻度污染和严重污染时相对误差较小(3. 23%和26. 75%);微脉冲激光雷达在良和轻度污染时相对误差较小(40. 00%和25. 81%)。2部雷达设备的差异和重污染时不利的气象条件是影响雷达表现的重要原因。该研究作为全国激光雷达联网的前期工作,为全国激光雷达数据的综合应用提供了参考。  相似文献   

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省级环境监测信息系统的设计与实现   总被引:6,自引:0,他引:6  
阐述了基于Web的省级环境监测数据库系统和地理信息系统的设计与实现方法、功能特点和组成结构,并就关键技术问题的解决途径进行了简要分析.系统的设计与实现充分体现先进性、开放性、可扩充性与实用性的特点,同时又满足了省级环境监测信息系统对于数据安全性、及时性和准确性的要求.  相似文献   

9.
The Environmental Monitoring and Assessment Program (EMAP) collects data that are used to statistically assess the environmental condition of large geographic regions. These data are then posted on the EMAP web site so that anyone can use them. Databases used for the statistical analyses, "analytical" databases, differ in design from the "general-use" databases used by a secondary audience. Their scope is usually restricted in time, in geographic extent, and in type and content of data, often being limited to a single scientific discipline. Their structure may be more horizontal than vertical, so that statistical programs can import the data easily. Their design is strongly influenced by the nature of the scientific analysis because the goal is to create a good computing environment for that analysis. We illustrate these aspects of design with an analytical database for estuaries in the U.S. mid-Atlantic region.  相似文献   

10.
Urban trees serve important environmental, social and economic functions, but similar to other natural endowments they are not customarily depicted in monetary terms. The needs to augment protection, funding and community support for urban greening call for proper valuation. Heritage trees (HTs), the cream of urban-tree stock, deserve special attention. Existing assessment methods do not give justice to outstanding trees in compact cities deficient in high-caliber greenery, and to their social-cultural-historical importance. They artificially separate evaluation from valuation, which should be a natural progression from the former. Review of tree valuation methods suggested the formula approach to be more suitable than contingent valuation and hedonic pricing, and provided hints on their strengths and weaknesses. This study develops an alternative formulaic expert method (FEM) that integrates evaluation and valuation, maximizes objectivity, broadly encompasses the key tree, tree-environment and tree-human traits, and accords realistic monetary value to HTs. Six primary criteria (dimension, species, tree, condition, location, and outstanding consideration) branched into 45 secondary criteria, each allocated numerical marks. Each primary criterion was standardized to carry equal weight, and a tree's maximum aggregate score is capped at 100. A Monetary Assignment Factor (MAF) to consign dollar value to each score unit was derived from three-year average per m2 sale price of medium-sized residential flats. The applicability of FEM was tested on selected HTs in compact Hong Kong. The aggregate score of a tree multiplied by MAF yielded monetary value, which was on average 66 times higher than the result from the commonly-adopted Council of Tree and Landscape Appraisers method. The computed tree values could be publicized together with multiple tree benefits to raise understanding and awareness and rally support to protect HTs. The property-linked FEM could be flexibly applied to other cities, especially to assess HTs in compact developing cities.  相似文献   

11.
Spatially explicit harvest scheduling models that can promote the development of dynamic mature forest patches have been proposed in the past. This paper introduces a formulation that extends these models by allowing the total perimeter of the patches to be constrained or minimized. Test run results suggest that the proposed model can produce solutions with fewer, larger, and more compact patches. In addition, patches are more likely to be temporally connected with this formulation. Methods for identifying the tradeoffs between the net present value of the forest and the size and perimeter of the evolving patches are demonstrated for a hypothetical forest.  相似文献   

12.
A graphical heuristic was devised for locating upgradient groundwater monitoring wells near landfills. Utilizing computer-simulated contaminant plumes, the heuristic considers the direction of groundwater flow relative to the shape of a landfill, the location of the downgradient migration boundary used for configuring detection wells, and uniformity of spatial coverage. The heuristic positions upgradient wells far enough from a landfill to avoid contamination, but close enough to measure ambient water quality near the landfill. It can be adapted to nonuniform flow fields, nonlinear migration boundaries, and irregularly shaped landfills. An application to a rectangular landfill, oriented at various angles to the direction of groundwater flow, demonstrates the utility of the approach.  相似文献   

13.
The question of how best to go about determining the significance of impacts has, to date, only been addressed in a partial and preliminary way. The assumption tends to be made that it is either only necessary to provide explicit, justified reasons for a judgment about significance and/or to explicitly apply a prescribed procedure—a procedure usually involving the staged application of thresholds and/or criteria. The detailed attributes, strengths and limitations of such approaches and possible alternative approaches have yet to be explored systematically.This article addresses these deficiencies by analyzing the characteristics, specific methods and positive and negative tendencies of three general impact significance determination approaches—the technical approach, the collaborative approach and the reasoned argumentation approach. A range of potential composite approaches are also described. With an enhanced understanding of these approaches, together with potential combinations, EIA practitioners and other EIA participants can be in a better position to select an approach appropriate to their needs, to reinforce the positive tendencies and offset the negative tendencies of the selected approach and to combine the best qualities of more than one approach.  相似文献   

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国内外空气质量监测网络设计方法研究进展   总被引:2,自引:3,他引:2  
如何设计效率高、代表性好、目的性强的空气质量监测网络,是长期以来空气质量监测工作的难点与关键。随着环境管理水平的提高,环境空气质量监测网络的设计成为当前研究的热点之一,国内外很多学者对其进行了广泛的研究。文章对美国、欧盟和我国关于空气质量监测网络设计的规范进行了简要评述和比较分析,并参考国内外一些关于空气质量监测网络设计的研究和应用实例,对当前主要的设计方法及应用进展进行了综述。  相似文献   

16.
During the past thirty years, researchers have been documenting the concentrations and effects of persistent toxic substances, such as DDT, PCBs, dioxins and furans, in populations of Great Lakes organisms. In designing the International Joint Commission's Workshop on Environmental Results, the organizers on the Great Lakes Science Advisory Board started from the premise that the selection of indicator organisms for long-term trend analysis requires that the causal relationships between the observed effects and the putative cause should be demonstrated and believed. However, the causal relationships that have been documented have generally been met with skepticism by fellow scientists and by regulatory officials resulting in no agreement on valid indicator organisms. To overcome this skepticism, wildlife, fisheries and human health researchers have adapted the epidemiological criteria used by medical and veterinary researchers for synthesizing the causal evidence. Brief reviews of several candidate species and of their suitability as long term monitors are presented, and the adequacy of monitoring programs for determining trends in the incidence of chemically-induced effects is assessed.  相似文献   

17.
The lagoon of Biguglia (northeastern Corsica) is one of a number Nature Reserve. Anthropogenic activities are increasing over its watershed however. The present study aims to examine the state of health of the lagoon with the example of two pollutants (Cd and Cu). Water samples were collected in spring and summer 1997. The trace metal fluxes between the various compartments were measured. Transfer processes from the watershed to the lagoon were also examined. The temporal evolution of Cd and Cu content is assessed on the one hand by comparing the present data with former reference work (1992). On the other hand, a 5-box model is implemented in order to reduce the complex functioning of the lagoon to a system of differential equations. With the help of a numerical resolution method, the increase of metallic concentration levels is estimated since 1992. On the basis of 1997 data, two hypotheses are compared. The hypothesis that takes into account a growing increase of anthropogenic activities on the watershed gives, by extrapolation, results that are closer to field measurements. However, even with this hypothesis, the cadmium content in the lagoon is underestimated. This may signify that for this metal the evolution of the lagoon pollution is more important than a linear increase.  相似文献   

18.
A quantitatively robust yet parsimonious air-quality monitoring network in mountainous regions requires special attention to relevant spatial and temporal scales of measurement and inference. The design of monitoring networks should focus on the objectives required by public agencies, namely: 1) determine if some threshold has been exceeded (e.g., for regulatory purposes), and 2) identify spatial patterns and temporal trends (e.g., to protect natural resources). A short-term, multi-scale assessment to quantify spatial variability in air quality is a valuable asset in designing a network, in conjunction with an evaluation of existing data and simulation-model output. A recent assessment in Washington state (USA) quantified spatial variability in tropospheric ozone distribution ranging from a single watershed to the western third of the state. Spatial and temporal coherence in ozone exposure modified by predictable elevational relationships ( 1.3 ppbv ozone per 100 m elevation gain) extends from urban areas to the crest of the Cascade Range. This suggests that a sparse network of permanent analyzers is sufficient at all spatial scales, with the option of periodic intensive measurements to validate network design. It is imperative that agencies cooperate in the design of monitoring networks in mountainous regions to optimize data collection and financial efficiencies.  相似文献   

19.
Suddenly occurring and time limited chemical exposures caused by unintended incidents might pose a threat to many workers at various work sites. Monitoring of exposure during such occasional incidents is challenging. In this study a compact, low-weight and personal semi-automatic pumped unit for sampling of organic vapor phase compounds from occupational air during sporadic and suddenly occurring incidents has been developed, providing simple activation by the worker potentially subjected to the sudden occurring exposures when a trained occupational hygienist is not available. The sampler encompasses a tube (glass or stainless steel) containing an adsorbent material in combination with a small membrane pump, where the adsorbent is capped at both ends by gas tight solenoid valves. The sampler is operated by a conventional 9 V battery which tolerates long storage time (at least one year), and is activated by pulling a pin followed by automatic operation and subsequent closing of valves, prior to shipping to a laboratory. The adjustable sampling air flow rate and the sampling time are pre-programmed with a standard setting of 200 mL min(-1) and 30 min, respectively. The average airflow in the time interval 25-30 min compared to average airflow in the interval 2-7 min was 92-95% (n = 6), while the flow rate between-assay precisions (RSD) for six different samplers on three days each were in the range 0.5-3.7%. Incident sampler recoveries of VOCs from a generated VOC atmosphere relative to a validated standard method were between 95 and 102% (+/-4-5%). The valves that seal the sampler adsorbent during storage have been shown to prevent an external VOC atmosphere (500 mg m(-3)) to enter the adsorbent tube, in addition to that the sampler adsorbent is storable for at least one month due to absence of ingress of contaminants from internal parts. The sampler was also suitable for trapping of semi-volatile organophosphates.  相似文献   

20.
Over the past decade, the cause of nature preservation in Singapore had gained momentum through the efforts of the various non-governmental organisations. Tussles over disputed nature areas such as the Lower Peirce Forest, Marina South, Senoko, etc., had also garnered a great deal of publicity in the mass media. Many arguments for nature conservation were given by conservationists --- from the economic to the ecological --- without considering carefully their local relevance and impact. This paper provides an outline of a value orientation for nature preservation in Singapore --- taking into account the local context in terms of the economic, cultural, social and ecological conditions existing in this country. The major values usually associated with nature conservation are reviewed and prioritised in terms of local relevance and impact. The strategic thrust of the value orientation advocated is, in the final analysis, anthropocentric rather than non--anthropocentric in perspective.  相似文献   

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