基于TM图像的城市生态绿地格局分析与评价

通过对遥感图像的校正、增强、变换和相关性分析等预处理,实现了TM图像的信息提取和精度分析。结果表明,基于TM图像的遥感分析与评价方法能够准确描述城市生态绿地格局在宏观和微观方面的基本特征。     

陕甘宁接壤区气候暖干化及其生态环境意义

应用陕甘宁接壤区1951-2000年气温、降水及1956-2000年陕甘宁接壤区 7条主要河流径流量实测记录,在实地调研的基础上对气象数据和水文数据分析后得出结论,陕甘宁接壤区近年来气候呈现暖干化趋势,全区增温线性倾向值为 0．194℃／10 a,高于全球近百年的趋势（0．05℃／10 a）,区内增温趋势强弱差异显著。陕甘宁接壤区气候变干表现在 2个方面：①年降水量减少;②地表径流量减少。降水线性倾向值平均为－1．0759 mm／a,地表径流总量1956-2000年减少速率为 0．4844 m³／a。陕甘宁接壤区生态环境在暖干化的气候背景下继续恶化,生态贫水化严重,水土流失加剧,沙漠扩大。     

Environmental history of an urban lake: a palaeolimnological study of Lake Jyväsjärvi, Finland

Sedimentary diatom frustules and chironomid remains, in addition to the chemical stratigraphy of 32 elements and organic pollutants such as resin acids, PCB, DDT and its metabolites, were studied from core samples taken from Lake Jyväsjärvi in Central Finland (64° 14 N, 25° 47 E). The sediment profile covered over 200 years, with the oldest samples representing a period of very low human interference. The town of Jyväskylä was established on the lake shore in 1837, and the lake received untreated municipal wastewater from the town up until, 1977. A paper mill started operations in 1872 and began discharging effluent into Lake Jyväsjärvi. In recent years this effluent loading has been reduced. Based on the biological and chemical properties of the sediment strata, five developmental phases were distinguished and named as follows: (1) a pre-industrial phase (approximately up until the 1860s); (2) a phase of early changes in the lake ecosystem (from the 1870s to ca. 1940s); (3) a phase of increasing eutrophication (from ca. 1950 to ca. 1965); (4) a phase of severe pollution (from ca. 1966 to the early-1990s); and (5) a phase of recovery, which proceeded more quickly during the late-1990s following long-term hypolimnetic aeration. It was estimated that the ecological status of the lake changed from good to moderate during the second phase. Due to the poor chemical status of the lake (including increased concentrations of harmful substances) and the pronounced changes in diatom and chironomid communities, the ecological status from 1950 to the early-1990s was classified as bad. The present ecological status, after a slow recovery of about 20 years, can be classified as moderate/poor. Chemical analysis of the sediment revealed that some elements (C, N, P, S, Ba, Cd, Cu, Fe, Pb, Ni and Zn) followed the known history of municipal waste water discharge into the lake, but Hg, Cr and persistent organic pollutants had different stratigraphies, and therefore mainly originated from other sources. Pronounced changes in profundal benthic communities (chironomids) started about 80 years later than those in diatoms, but later changes in chironomid assemblages were greater than those in diatoms.     

Species sensitivity distributions: data and model choice

Species sensitivity distributions (SSDs) are increasingly incorporated into ecological risk assessment procedures. Although these new techniques offer a more transparent approach to risk assessment they demand more and superior quality data. Issues of data quantity and quality are especially important for marine datasets that tend to be smaller (and have fewer standard test methods) when compared with freshwater data. An additional source of uncertainty when using SSDs is appropriate selection from the range of methods used in their construction. We show through examples the influence of data quantity, data quality, and choice of model. We then show how regulatory decisions may be affected by these factors.     

A GIS-based mapping method on distribution of critical Ecological Situation in China

Introduction Human-induced environmental change in China has led to different consequences due to various causes. They conver certain regions and places where their impacts may threaten the long-term or even the short-term sustainability of human-environmental relationships. Designating such areas as "critical environmental situations," Russian Geographers have developed "red data maps" showing their locations[1]. Yet, there are no fully developed conceptualizations of environmental critical…     

The GW-Fauna-Index: A first approach to a quantitative ecological assessment of groundwater habitats

Between June 2001 and December 2002, 18 hyporheic and groundwater bores were sampled for fauna and environmental data using phreatic traps. The bores were situated in three different natural geographic regions in Palatinate, Southwestern Germany.Faunal data correlated with the relative amount of detritus, bacterial abundances and the standard deviation of temperature, while very few and weak correlations were found with physical–chemical variables. Dissolved oxygen was assumed to be a limiting factor for most metazoans with a critical concentration at around 0.5–1 mg l⁻¹.To quantify the strength of the hydrological exchange with surface water and its effects on fauna, a so-called GW-Fauna-Index was developed and calculated using the relative amount of detritus, standard deviation of temperature, and oxygen concentration. From all environmental data and on all spatial scales, this index best explained the total faunal abundance and taxonomic richness.To describe the availability of organic aliments in the groundwater, the terms of “alimonic” and “alimony” [from lat. alimonium=(food) supply] were proposed.Although stygofauna was different in the geographic regions investigated, the GW-Fauna-Index was independent from these regional particularities. Using the GW-Fauna-Index, three groups of groundwater habitats could be classified according to the alimonic conditions. From oligo-alimonic group I samples, fauna was mostly absent, while meso-alimonic group II samples were prevailingly populated by stygobites, and eu-alimonic group III samples by ubiquists and stygoxenes. Total abundances and taxonomic richness increased significantly from group I to group III. Group I samples were characterized by low index values, group II samples by intermediate and group III samples by high values.The GW-Fauna-Index provides promising perspectives for application, but needs some improvement. First of all, detritus should be analysed quantitatively and qualitatively, rather than semi-quantitatively. Also, a standard protocol for sampling has to be developed.     

水稻免耕栽培的减灾效应研究

为探索稻田保护性耕作技术——水稻免耕的减灾效应,将免耕与传统稻作方法相结合组成常耕移栽、常耕抛秧、免耕移栽、免耕抛秧4个处理进行试验,并运用生态学原理对试验结果进行了分析研究。结果表明,稻田保护性耕作能提高作物产量,降低部分生育期间水稻病虫害,抑制农田杂草的生长。     

Evaluation of landscape changes and ecological degradation by GIS in arid regions: a case study of the terminal oasis of the Shiyang River,northwest China

The development and utilization of water and land resources in the Shiyang River basin are the highest among the inland rivers in northwestern China. Using GIS and the landscape structure analysis program FRAGSTATS, landscape metrics of a study area in the lake-district in Minqin Oasis in the lower reaches of Shiyang River basin were calculated and analyzed based on TM images from 1987 to 2001 at class level and landscape level, respectively. Transformation matrix of the landscape mosaics was also examined. The driving forces of landscape changes were analyzed, including the dynamics of runoff and groundwater resources and their exploitation, and influences of policies and market economy. The results showed that: (1) Patch number of farmland and desert decreased, but their mean patch area increased, indicating that reclamation and desertification was very serious in the study area. Contagion index for oasis increased and edge density and landscape diversity were reduced. (2) Farmland and desert areas have enlarged by 1,520.46 and 4,941.27 hm², respectively. This increase was at the cost of woodland and grassland, which shrank by 1,520.46 and 4,941.27 hm², respectively. (3) The net utilization of surface water decreased by 50% in the last 10 years, and dropped to 22.3 × 10⁶ m³ in the later 1990s. Exploitation of groundwater increased remarkably, up to 80 × 10⁶ m³ per year in the last 5 years. (4) The capability of the economic structure to withstand pressures of the market economy has depressed distinctly because of the simplified planting pattern, which is dominated by salinity-enduring cash crops, such as cotton. Based on the above analysis, strategies of ecological reconstruction in the lake-district were suggested.     

Modeling errors in upward continuation for INS gravity compensation

Accurate upward continuation of gravity anomalies supports future precision, free-inertial navigation systems, since the latter cannot by themselves sense the gravitational field and thus require appropriate gravity compensation. This compensation is in the form of horizontal gravity components. An analysis of the model errors in upward continuation using derivatives of the standard Pizzetti integral solution (spherical approximation) shows that discretization of the data and truncation of the integral are the major sources of error in the predicted horizontal components of the gravity disturbance. The irregular shape of the data boundary, even the relatively rough topography of a simulated mountainous region, has only secondary effect, except when the data resolution is very high (small discretization error). Other errors due to spherical approximation are even less important. The analysis excluded all measurement errors in the gravity anomaly data in order to quantify just the model errors. Based on a consistent gravity field/topographic surface simulation, upward continuation errors in the derivatives of the Pizzetti integral to mean altitudes of about 3,000 and 1,500 m above the mean surface ranged from less than 1 mGal (standard deviation) to less than 2 mGal (standard deviation), respectively, in the case of 2 arcmin data resolution. Least-squares collocation performs better than this, but may require significantly greater computational resources.     

A review of ecological risk assessment and associated health risks with heavy metals in sediment from India

Heavy metal (HM) pollution in sediment is a serious concern particularly in developing nations, warranting an extensive survey to understand the current situation and propose possible remedial measures. This paper compiles the data of HMs cadmium (Cd), iron (Fe), cobalt (Co), manganese (Mn), arsenic (As), lead (Pb), chromium (Cr), copper (Cu), zinc (Zn) and nickel (Ni) in aquatic sediment from India from 1979 to 2017. It was found that mean values of Cu, Co, Zn, Pb, As, and Cr in Indian sediment were high in comparison to the Australian Interim Sediment Quality Guidelines, World Surface Rock Average, and the Threshold Effect Level for freshwater ecosystems. Anthropogenic activities, lithogenic factors, and sand intrusion are the main factors associated with HM pollution as observed using cluster analysis and principal component analysis. The results of contamination indices indicate that HM contamination ranged from average to high, in the sediment. The ecological risk assessment results showed that 11% HMs present very high risk. The cancer risk, due to the high contents of Cd, As, and Cr the ingestion pathway, showed high risk of cancer through food/water contaminated with sediment. At source reduction of HMs in industrial effluents by effluent treatment plants, and plantation of phytoremediating rooted macrophytes in sediment may help in HM mitigation of the sediment.