苹果绵蚜种群的空间分布型及其应用——Ⅰ.秋季种群

生物种群的空间分布是一种高度特化的生物学特性,是长期适应自然环境的结果。在理论上,研究种群的空间分布有助于理解种群的生态学特性以及种群与所处环境的相互关系;在实践中,种群的空间分布是确定生物统计分析的资料代换方法和制定抽样技术方案的依据。 苹果绵蚜Eriosoma lanigerum(Hausm.)是苹果树的毁灭性害虫。50年代云南仅昆明地区有苹果绵蚜的分布,现在苹果绵蚜已侵入到云南许多苹果产区。1978年苹果绵蚜侵入到丽江县,其危害相当严重。过去的工作主要集中在生物学和防治方面,空间分     

Exploring an efficient habitat index for predicting population and abundance of migratory birds in Poyang Lake Wetland,South China

Poyang Lake wetland is an important wintering habitat of migratory birds with a complexity of coupled nature and human systems. Reported studies suggested that habitat indices were mostly developed based on single-class factors and scale-dependent. Therefore the indices might not be sufficient and applicable to predict regional changes for population and abundance of migratory birds (PMB and AMB) in Poyang Lake wetland at watershed and basin scales. In order to explore an efficient habitat index for predicting PMB and AMB, an integrated and scale-independent habitat index was proposed by integration of landscape and environmental temperature variables at basin and watershed scales. The landscape index and environmental temperature index based on single-class dominant factors, were also evaluated by weighted additive method. Multi-source data, including multi-spatial and temporal remote sensing images and field survey data, was used in this study. Results indicated that the average 10-night temperature in July (TN-Jul.) had dominant influence on PMB and the environmental temperature index was a better predictor for predicting PMB; AMB was influenced by both landscape and temperature variables and the proposed integrated habitat index was better for prediction of AMB in Poyang Lake wetland. The proposed integrated habitat index is a supplement of the single-class habitat index, which provides a more scientific technique for the study of biodiversity.     

River quality analysis using fuzzy water quality index: Ribeira do Iguape river watershed, Brazil

Intrinsic uncertainties and subjectivities of environmental problems have been increasingly dealt by using computation methods based on artificial intelligence. In order to evaluate this tool's applicability, this study proposed the creation of a new water quality index based on fuzzy logic, the fuzzy water quality index (FWQI). The performance of the index proposed in the present work is assessed through a comparison with several water quality indices (WQIs) suggested in the literature, using data from hydrographic surveys of the Ribeira de Iguape River, in the southwestern part do São Paulo State, Brazil, from 2004 to 2006. The index was reasonably close to the other indices and showed a good correlation with the WQI traditionally calculated in Brazil. This new index may also be used as an alternative tool for decision-making in environmental management.     

红松存在/不存在数据的多尺度空间分布格局

红松属小兴安岭地区地带性植被优势种,该地区也是其分布的北缘。在景观尺度上开展红松的分布格局研究有利于进一步了解红松分布机理、未来迁移过程等问题,对其经营和保护有重要意义。将景观指数法与点格局分析法结合,设定8个空间尺度,利用红松存在/不存在数据,通过计算各空间尺度上红松聚集程度和景观指数,分析小兴安岭地区红松种群在多尺度上的分布格局。研究结果表明,小尺度上红松聚集分布明显,随机分布区多处于其聚集分布区的边缘,均匀分布区则散布在其聚集分布区内。景观指数研究表明,通过景观指数可判断红松聚集分布格局趋势,而不能判断均匀分布、随机分布格局趋势,因为它们在多尺度下景观指数波动大,不能用景观指数来描述分布格局。研究得出如下结论:1)红松主要分布在其分布区的核心区域内,在分布区边缘和过渡带上呈随机分布,2)存在/不存在数据能够用来分析种群的多尺度空间分布格局,3)空间尺度的变化会引起树种分布格局的变化,随机分布随尺度增加,边缘化程度加强,4)单一尺度上,景观格局指数不能完全描述种群分布格局;而在多尺度上,变化趋势稳定的景观指数表明聚集分布存在,而波动剧烈的景观指数常与随机分布和均匀分布联系在一起,5)地形因子中,红松对坡度和海拔两个因子变化敏感。     

Classification and change detection of built-up lands from Landsat-7 ETM+ and Landsat-8 OLI/TIRS imageries: A comparative assessment of various spectral indices

Since the mid-1990s, various spectral indices have been proposed for the rapid and accurate classification of built-up lands from satellite imageries. However, a comprehensive comparison between these indices as applied to various satellite imageries is still lacking. Hence, this study examines and compares the performance of six spectral indices in the classification and change detection of built-up lands from Landsat-7 ETM+ (Enhanced Thematic Mapper Plus) and Landsat-8 OLI/TIRS (Operational Land Imager/Thermal Infrared Sensor) imageries. It includes three mid-infrared (MIR)-based indices, i.e. the urban index (UI), the normalized difference built-up index (NDBI), and the index-based built-up index (IBI), two proposed visible (Vis)-based indices, i.e. the VrNIR-BI and VgNIR-BI or the visible red/green-based built-up indices, and one thermal infrared (TIR)-based index, i.e. the normalized difference impervious surface index (NDISI). In addition, a water index, i.e. the modified normalized difference water index (MNDWI), was also derived. Otsu's method was used to separate water from the non-water areas on the MNDWI map. Subsequently, a water mask was produced and used to mask all the built-up index maps, leaving only the non-water areas. Using the same thresholding method, the non-water areas of all the built-up index maps were classified into built-up and non-built-up classes. The classification accuracy was assessed using 5000 reference points for each image. The results show that the VrNIR-BI, with an overall accuracy of 92.50% (Landsat-7) and 92.28% (Landsat-8), and the VgNIR-BI, with 92.78% (Landsat-7) and 92.14% (Landsat-8) overall accuracy, were more robust and superior. They were more accurate than the other indices by up to 8% for the Landsat-7 ETM+ image and 10% for the Landsat-8 image OLI/TIRS image. The qualitative assessment results also supported these quantitative findings. The results also show indications that the detected spatiotemporal urban LUC changes (i.e. built-up expansions) based on the VrNIR-BI and VgNIR-BI were also the most accurate. These indices, i.e. the proposed Vis-based indices, have better potential in separating built-up lands from dry vegetation, which has been an important challenge in the application of spectral indices for classifying built-up lands from satellite imageries.     

山东泰安泰兴苗圃紫薇梨象成虫种群的空间格局

应用聚集度指标法和地统计学方法对山东泰安泰兴苗圃紫薇重要害虫紫薇梨象成虫的垂直分布和水平分布进行研究.传统统计学分析表明,紫薇梨象成虫的垂直分布为聚集分布,聚集均数λ大于2,聚集是由其本身行为和习性引起的,而不是由环境因子引起的.地统计学分析表明,在6月4日、16日、29日、7月25日和8月22日5个时间点的半变异函数拟合模型分别为高斯模型、高斯模型、线性模型、高斯模型和线性模型,而在7月12日和8月7日为随机模型.紫薇梨象成虫种群水平分布总体上为聚集分布,且成虫间存在空间相关性.紫薇梨象成虫种群在不同时间的空间相关范围即变程在1.68～9.79.
     

Assessment of sustainable development in the EU 27 using aggregated SD index

In the European Union the sustainable development is a fundamental and overarchingobjective enshrined in the Treaty and measuring progress towards sustainable development is an integral part of the EU Sustainable Development Strategy. Eurostat produce a monitoring report every two years based on the EU set of sustainable development indicators (SDIs). The main objective of this paper is to create an aggregated index of the sustainable development from EU set of SDIs for each 27 EU country based on the PCA. The headline indicator economic growth was not involved because its increase is not expressly followed by positive change in other SDIs from social, economic and environmental fields. The aggregated SD index enables to get an overall picture about the position of each of the 27 EU countries and its development in terms of the sustainability over time as assumed in the EU Sustainable Development Strategy. Sweden, Denmark, Netherland, and Great Britain have repeatedly reached the highest value of aggregated SD index. The highest positive change in the aggregated SD index has occurred in countries with the lowest value of aggregated SD index. Moreover, we put this new aggregated index in relation with economic growth and found that there is a negative correlation between aggregated SD index and the economic growth for most of the 27 EU countries.     

Aggregated indices for trends in eutrophication of different types of fresh water in the Netherlands

As in many European countries, eutrophication of surface waters is a key problem in the Netherlands, caused by high concentrations of nitrogen (N) and phosphorus (P). For implementation of the EU Water Framework Directive (WFD) in the Netherlands, surface water types have been identified and for each water type environmental quality standard concentrations (EQS) were determined for both nutrients. With these standards, a new method was developed to quantify trends in water quality with respect to eutrophication on a national scale for the period 1990–2010. Firstly, monitoring data were aggregated to seven classes of surface water. Next, for each water class and each nutrient, a Nutrient Index was developed to express the degree of exceedance of EQS (distance-to-target method). The Nutrient Index for N shows a minor exceedance of EQS as well as an improvement in all water types; for P, the index shows a major exceedance in small stagnant waters throughout the 1990–2010 period, whereas in major rivers and lakes levels were close to EQS. Thirdly, the indices for seven surface water classes were aggregated to one index for each nutrient, and finally to a national Eutrophication Index combining N and P. This Eutrophication Index integrates all monitoring data and shows an improvement in the period 1990–2003 and stabilization since 2004.     

Laplacian Estrada and Normalized Laplacian Estrada Indices of Evolving Graphs

Large-scale time-evolving networks have been generated by many natural and technological applications, posing challenges for computation and modeling. Thus, it is of theoretical and practical significance to probe mathematical tools tailored for evolving networks. In this paper, on top of the dynamic Estrada index, we study the dynamic Laplacian Estrada index and the dynamic normalized Laplacian Estrada index of evolving graphs. Using linear algebra techniques, we established general upper and lower bounds for these graph-spectrum-based invariants through a couple of intuitive graph-theoretic measures, including the number of vertices or edges. Synthetic random evolving small-world networks are employed to show the relevance of the proposed dynamic Estrada indices. It is found that neither the static snapshot graphs nor the aggregated graph can approximate the evolving graph itself, indicating the fundamental difference between the static and dynamic Estrada indices.     

F-IND: A framework to design fuzzy indices of environmental conditions

Multivariable indices of environmental conditions summarize the information provided by several biotic or abiotic variables into a single value of immediate interpretability. Thus they are important instruments for monitoring. Developing new indices that combine different variables is not a trivial task: variables may be qualitative, or measured in different units, and the relationship between primitive components and quality may be ambiguous. Fuzzy logic has been repeatedly proposed as an effective technique to cope with such problems; however, the variety of choices that exist at each stage of the development of fuzzy models may present a problem for the index designer. In this paper we present F-IND, a framework to create fuzzy indices by means of a simplified and intuitive procedure. It allows to capture the expert knowledge of the system under study (air, soil, water) to easily generate a multivariable index of environmental conditions. F-IND is implemented in Java, to achieve an optimal portability on any operating system.     

动态适应性生态经济区划模型及其应用

提高城市生态经济区划的精确性和动态性,对科学指导城市化发展具有重要的理论意义和应用价值。利用夜间灯光数据与人口密度建立线性模型,探索了以往用行政区域为最小统计单元数据的模拟细化问题;然后通过引入可变参数构建了动态适应性生态经济区划模型,在增强模型动态适应性的同时,将一级区划结果统一划分为生态管控区域、生态优先区域、优化开发区域和重点开发区域4个区域。以广州市增城区为典型案例,通过改进的动态适应性生态经济区划模型,运用GIS将增城区在两种情景下进行了模拟和对比,并提出了政策建议。区划结果符合当地发展特征,也为其他城市与区域的生态经济区划研究提供了科学方法。     

Evaluating the performance of benthic multi-metric indices across broad-scale environmental gradients

The usefulness of benthic multi-metric indices when assessing seafloor integrity across broad environmental gradients should be deliberated, as their lack of transparency might hide important sources of variation and fail to identify environmental change. This study compares the performance of two multi-metric indices; the Benthic Quality Index (BQI) and the Brackish water Benthic Index (BBI) between three sub-basins in the Baltic Sea. Both indices reflect the salinity-driven gradient in macroinvertebrate diversity and composition as well as changes in bottom water oxygen concentrations. The relative contribution of predictor variables for explaining index variation does, however, differ between sub-basins, resulting in the indices representing different aspects of the benthic community along the environmental gradient. This context-dependency is caused by inherent differences in benthic community characteristics between the sub-basins of the Baltic Sea, and how the communities are portrayed by the indices. An increased transparency of the importance of the different predictors for directing index values is needed for coherent classifications over broad environmental gradients, such as those occurring in large estuarine water bodies. Use of a weight of evidence table to combine multiple indicators would preserve transparency and be more likely to provide a robust assessment method that would detect seafloor degradation at an early stage.     

野生罗汉果种群分布格局研究

采用方差/均值比率法对8个野生罗汉果种群的分布格局类型进行了分析,同时采用负二项式参数、扩散性指数、丛生指数、平均拥挤度指数和聚块性指数等计测这些种群的空间聚集强度。结果表明,罗汉果种群的分布格局呈随机或集群分布,不同种群的聚集强度有所差异。对这种分布格局形成的原因进行了分析。     

Measures, perceptions and scaling patterns of aggregated species distributions

Non-random (aggregated) species distributions arise from habitat heterogeneity and nonlinear biotic processes. A comprehensive understanding of the concept of aggregation, as well as its measurement, is pivotal to our understanding of species distributions and macroecological patterns. Here, using an individual-based model, we analyzed opinions on the concept of aggregation from the public and experts (trained ecologists), in addition to those calculated from a variety of aggregation indices. Three forms of scaling patterns (logarithmic, power-law and lognormal) and four groups of scaling trajectories emerged. The experts showed no significant difference from the public, although with a much lower deviation. The public opinion was partially influenced by the abundance of individuals in the spatial map, which was not found in the experts. With the increase of resolution (decrease of grain), aggregation indices showed a general trend from significantly different to significantly similar to the expert opinion. The over-dispersion index (i.e. the clumping parameter k in the negative binomial distribution) performed, at certain scales, as the closest index to the expert opinion. Examining performance of aggregation measures from different groups of scaling patterns was proposed as a practical way of analyzing spatial structures. The categorization of the scaling patterns of aggregation measures, as well as their over- and in-sensitivity towards spatial structures, thus not only provides a potential solution to the modifiable areal unit problem, but also unveils the interrelationship among the concept, measures and perceptions of aggregated species distributions.     

Definition and Estimation of Higher-Order Gene Fixation Indices

Fixation indices summarize the associations between genes that arise from the joint effects of inbreeding and selection. In this paper, fixation indices are derived for pairs, triplets and quadruplets of genes at a single multiallelic locus. The fixation indices are obtained by dividing cumulants by constants; the cumulants describe the statistical distribution of alleles and the constants are functions of gene frequency. The use of cumulants instead of moments is necessary only for four-gene indices, when the fourth cumulant is used. A second type of four-gene index is also required, and this index is based upon the covariation of second-order cumulants. At multiallelic loci, a large number of indices is possible. If alleles are selectively neutral, the number of indices is reduced and the relationship between gene identity and gene cumulants is shown.--Two-gene indices can always be estimated from genotypic frequency data at a single polymorphic locus. Three-gene indices are also estimable except when allele frequency equals one-half. Four-gene indices are not estimable unless selection is assumed to have an equal effect upon each allele (such as under selective neutrality) and the locus contains at least three alleles of unequal frequency. For diallelic or selected loci, an alternative four-gene fixation index is proposed. This index incorporates both types of four-gene associations but cannot be related to gene identity.     

Diatom Model Affinity (DMA), a New Index for Water Quality Assessment

A new index, diatom model affinity (DMA) was erected as a reference-based community metric, derived from generic and species composition. DMA provides an assessment of water quality by the calculation of percent similarity to a model community, which can be viewed as a reference standard. High similarity to the model indicates communities that are minimally disturbed, while lower similarity suggests water quality problems. The index is similar to that developed for macroinvertebrate communities by Novak & Bode (1992, Journal of the North American Benthological Society 11: 80-85). The index correlated well with environmental factors operating on hierarchical scales. Compared to other commonly used diatom indices, DMA-based community assessments demonstrated high correspondence to patterns derived from multivariate statistics.     

Evaluation of methods to estimate field vole Microtus agrestis abundance in upland habitats

Field vole abundance was assessed on a range of upland habitats in spring and autumn, using live—trapping, snap—trapping and vole sign index methods. Three estimates of vole numbers were derived from live—trapping, five from snap—trapping and one from vole signs. Estimates were compared using a correlation matrix in order to establish the most accurate and consistent method. Snap—trapping for five nights provided enough information to calculate vole density, though the method was time consuming. Vole abundance indices derived from two nights' snaptrapping were significantly correlated with indices from five nights' trapping. Live—trapping and vole sign index were discounted as methods for this study area, as both proved unreliable.     

Population fluctuations affect inference in ecological networks of multi‐species interactions

Local abundance and population fluctuations are key factors affecting the realized interaction frequencies in biotic interactions, but they are commonly ignored when network metrics are calculated over aggregated sets of observations. Here we studied how abundance fluctuations (i.e. demographic and stochastic population dynamics in one of the trophic levels) may affect derived network‐level inferences in bipartite ecological networks. Variation at both the species and network level in network indices (d’, Dependence, Fisher's alpha diversity for both levels, H₂’, weighted NODF) were strongly correlated with the extent of abundance fluctuations, with a strong effect of environmental stochasticity on all indices except NODF; this was the only index for which considerable variation was caused by varying carrying capacities among species. Binary connectance, in turn, does not take interaction frequency (and thus abundance) into account and was only influenced by abundance fluctuations at low population sizes if this led to non‐occurrence of ‘true’ interactions. Overall, abundance and population dynamics are likely to play an important role in determining what is commonly observed and summarized into ecological networks. We suggest that ecological network inference should account for underlying population dynamics and uncertainty in what is observed as interaction frequencies, modelling mechanisms at operative organisational levels below the network rather than using aggregated data of observations. Modelling population dynamics may be a valuable tool in this field to conceptualize and tease apart different sources of variation and express uncertainty in our inference from small samples.     

Integrated assessment of agricultural production practices to enhance sustainable development in agricultural landscapes

This study presents an integrated assessment approach for the sustainable development of agricultural landscapes. The approach evaluates single agricultural production practices by means of environmental, economic and social indicators. To implement the approach, a mixed method was employed that combines modelling techniques and survey methods. The economic and environmental indicators were implemented within the bio-economic modelling system MODAM (Multi-Objective Decision support system for Agro-ecosystem Management) in order to assess economic performance and the effects on the abiotic and biotic environments. The modelling approach was applied to a case study in a region of north-eastern Germany, within the state of Brandenburg. In addition, the acceptance by farmers of different production alternatives that are known to have environmental benefits was examined in the case study. To allow for a direct comparison between different indicators, the results of the assessment are dimensionless index values that indicate the suitability of certain agricultural production practices with respect to an indicator. The indicator-related indices are then aggregated into an overall index of sustainability differentiating between ‘strong’ and ‘weak’ sustainability. Results are presented for exemplarily chosen production practices for sugar beet, potato and winter rape production and set aside. Depending on the underlying concept of sustainability (‘weak’ vs. ‘strong’), different production practices were identified as the most suitable ones in a given situation. This integrated assessment enables determination of positive and negative correlations between indicators. The approach allows for the identification of production alternatives that are assessed to be economically and environmentally beneficial as well as socially accepted, although at different levels.     

Dispersion analyses and resource utilization of aphid parasitoids in a non-depletable environment

Dispersions and resource utilization of primary and secondary parasitoids developing in non-depletable primary host populations were determined for an aphid-parasitoid community occurring on strawberries. Analyses of dispersions based onGreen 's coefficient andLloyd 's Patchiness Index indicated parasitized aphids were highly aggregated initially, became less aggregated as density increased, and remained aggregated following collapse of the aphid populations. The “index of aggregation” values calculated usingTaylor 's Power Law concurred with results from the other indices, and the similarity of the regression coefficients from both seasons suggests that the index of aggregation may be characteristic for communities as well as species. Analysis withIwao 's regression of mean crowding on the mean generated similar results when population data were stratified temporally, and also indicated that the individual was the basic unit of the population. In a non-depletable environment, oviposition of individuals exhibiting an aggregated dispersion pattern within clumps of hosts provides primary parasitoids with a suitable trade-off between energy utilization or genetic potential, and losses associated with hyperparasitism.