首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
基于3S技术的乌梁素海环境监测信息系统的设计   总被引:4,自引:0,他引:4  
在乌梁素海生态治理中,以3S一体化技术为基础建立环境监测信息系统,对乌梁素海生态治理工程进行实时监测,对空间数据和非空间数据进行管理,并且建立工程技术档案库。在生态恢复与经济效益之间进行合理的规划与深层次的定位,考查各种营养盐输入与输出的关系,综合评价保护与开发的效应,从全面发挥乌梁素海多功能生态系统的作用上进行宏观调控,不断完善和修正生态治理规划中的各项技术指标,使这一生态系统长期进入良性循环状态。  相似文献   

2.
土壤的高光谱能够反映土壤信息,利用光谱数据能够快速高效地预测土壤重金属含量。以上海闵行工业区土壤为研究对象,分析研究区土壤光谱曲线所包含的土壤信息,通过光谱反射数据多种低阶微分变换形式以增强光谱特征,并通过相关分析获取土壤铜(Cu)、铬(Cr)、锰(Mn)、铅(Pb)、锌(Zn)含量的特征波段位置,构建土壤重金属高光谱反演模型。结果表明,工业区土壤重金属Cu、Cr、Mn、Pb、Zn存在明显积累,含量平均值依次为29.38、106.32、583.14、34.13、111.15 mg·kg-1,均超过上海市土壤环境背景值,且表现出复合污染和同源性的特点;土壤光谱曲线除受铁氧化物(409.55 nm)、有机质(825~900 nm)、水(1 400~1 425 nm)的影响存在光谱曲线吸收带外,走势均随波长增加而上升;最优特征波段均出现在近红外波段范围内,Cu为1 440.21 nm,Cr为834.44 nm,Mn为984.98 nm,Pb为1 440.21 nm,Zn为1 642.50 nm;利用特征波段光谱反射率的低阶微分变换形式作为建模因子建立土壤重金属含量的高光谱反演模型,发现均方根二阶微分(RMSTD)变换、倒数一阶微分(RTFD)变换、倒数对数二阶微分(ATSD)变换相较于原始一阶微分(FD)、二阶微分(SD)变换更能提高预测精度,多元逐步回归线性模型(SMLR)建模效果优于偏最小二乘回归(PLSR)模型,SMLR建模R2均大于0.65,验证R2除Mn外(R2=0.400)均大于0.5。基于SMLR建立的高光谱反演模型具有较高的预测精度、稳定性与可靠性,对工业区土壤重金属含量进行高光谱反演建模具有可行性。  相似文献   

3.
提出了以GM(1,1)模型拟合发展的趋势、傅里叶变换撮周期分量AR(p)模型模拟随机过程的集成预报模型,并用于黄河三角洲人工草场群落土壤盐分的定量研究中,经理论和应用检验证明:该模型能以较高的精度模拟或预报土壤盐分在较长时期内的动态变化过程,方法简单,计算工作量小,并优于传统的单一预报模型。  相似文献   

4.
在乌梁素海生态治理中,以3S一体化技术为基础建立环境监测信息系统,对乌梁素海生态治理工程进行实时监测,对空间数据和非空间数据进行管理,并且建立工程技术档案库。在生态恢复与经济效益之间进行合理的规划与深层次的定位,考查各种营养盐输入与输出的关系,综合评价保护与开发的效应,从全面发挥乌梁素海多功能生态系统的作用上进行宏观调控,不断完善和修正生态治理规划中的各项技术指标,使这一生态系统长期进入良性循环状态。  相似文献   

5.
干旱区绿洲耕层土壤重金属铬含量的高光谱估测   总被引:1,自引:0,他引:1  
土壤重金属铬含量的高光谱估测技术较传统测量方法具有无污染、方便快捷进行动态监测的优势。对新疆渭干河-库车河三角洲绿洲耕层土壤98个样品的原始光谱反射率R分别进行倒数1/R、对数lg(R)、倒数对数lg(1/R)以及微分变换。不同处理结果与实测土壤重金属铬含量进行相关分析从而筛选出具有极显著相关的特征波段(P0.001)。以不同变换处理下的特征波段反射率作为自变量,土壤铬含量为因变量,采用多元线性逐步回归、偏最小二乘回归、BP神经网络和随机森林回归方法构建土壤重金属铬含量的高光谱估测模型,并对最优估测结果进行克里格空间插值。结果表明,(1)原始光谱反射率的微分变换处理可有效提升光谱与土壤重金属铬含量之间的敏感性,其中经微分变换后的土壤光谱反射率与铬含量的相关系数由0.487显著提高到0.669(P0.001)。(2)综合比较各模型的训练集和验证集估测结果,经倒数对数一阶微分[lg(1/R)]′处理后的BP神经网络模型具有较高的估测精度和很强的稳定性,可作为研究区土壤重金属铬含量的最优估测模型,其决定系数(Rd~2)在0.8以上,均方根误差(RMSE)小于6.5,相对分析误差(RPD)大于2。(3)研究区土壤重金属铬含量具有中等空间变异性,低含量区域主要分布在新和县和沙雅县的外缘地带,而位于库车市东北部区域的耕层土壤铬含量达到最高水平。受人类活动影响该绿洲的土壤污染问题日趋严重,耕层土壤重金属铬含量呈现出较高含量的空间分布。  相似文献   

6.
简要介绍了土地定级信息系统和土地估价信息系统的软件和硬件配置、系统的结构与功能,并以通州市为例,阐述了土地定级信息系统的基本算法和模型参数的确定方法。  相似文献   

7.
简要介绍了土地定级信息系统和土地估价信息系统的软件和硬件配置、系统的结构与功能,并以通州市为例,阐述了土地定级信息系统的基本算法和模型参数的确定方法。  相似文献   

8.
研究应用地理信息系统构建广东省土壤资源信息系统的总体模式,建立了土壤资源信息系统的基本功能构成;探索了土壤资源空间信息与文献资料的Internet网络化这一土壤研究新领域,并实现了土壤资源空间信息Internet网络化.  相似文献   

9.
从数字化一张封丘县土地利用现状图的实例开始,着重介绍使用GenaMap采集地图数据的全过程和关键步骤,数字化仪,数字化一张新图,数字化一张未完的图、GenaMap的一些重要命令等。  相似文献   

10.
基于高光谱的邯郸市土壤重金属统计估算模型研究   总被引:1,自引:0,他引:1  
土壤重金属富集严重制约城市发展,对居民健康造成潜在威胁。该研究旨在定量估算土壤重金属含量,提高土壤重金属监测时效性,从而为土壤保护管理工作提供决策参考和理论支持。该文依据化学检测所得土样重金属含量与地物光谱仪(ASD)获取的土壤反射光谱数据,通过对土壤重金属光谱特性的分析,确定光谱反演特征波段,研究并建立了邯郸市土壤重金属基于不同光谱变换指标的多元逐步回归(SMLR)和偏最小二乘回归(PLSR)统计估算模型,通过模型验证与对比,探索邯郸市土壤各重金属含量的最优反演模型。结果表明:(1)微分处理能普遍改善模型预测效果,二阶微分指标的PLSR与MLSR模型效果较佳;(2)PLSR与SMLR两种建模方法相比,总体上PLSR建模和预测的均方根误差RMSE较小、模型修正系数Adjust R~2较大,表明PLSR模型预测效果更好;(3)基于反射率倒数对数的二阶导数的PLSR模型反演效果较优,其中Cu、Ni、Zn、Hg,检验精度Adjust R2均超过0.8。  相似文献   

11.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

12.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

13.
An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.  相似文献   

14.
How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.  相似文献   

15.
Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.  相似文献   

16.
17.
Parasitic wasps orient to green leaf volatiles   总被引:12,自引:0,他引:12  
Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture  相似文献   

18.
Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras  相似文献   

19.
The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.  相似文献   

20.
International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).  相似文献   

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