右江流域水生态补偿机制研究初探

为保护右江流域生态环境,协调郁江乃至珠江上下游各方经济利益,更好的激励上游地区生态环境保护行为,通过分析右江流域水生态现状、存在问题、现有生态补偿政策环境及其在郁江流域、珠江流域中的地位和作用,利用外部性理论,分析提出了右江流域水生态补偿模式。通过对标对表有关生态保护规划和区划成果,立足百色市实际,提出了右江流域水生态补偿内容、补偿主客体、补偿标准和补偿方式,初步构建右江流域水生态补偿机制框架,并提出有针对性的补偿政策建议,为水生态补偿实施提供了参考。     

JT6120乘客座椅靠背曲线静态舒适性评价研究

The aim of this research was to evaluate a passenger seat of a new type bus in terms of eomfort. A fuzzy set model of multistage comfort scale (MCS) was adopted to the assessment of comfort, together with the techniques of human backshape and EMG measures     

三峡库区柑桔林水土保持效益分析

对三峡库区2种不同建园方式的柑桔林,从建园开始连续9年定位观测柑桔林水土流失情况,结果表明,梯田柑桔林径流系数在0.047~0.153之间,径流含沙量在425~2170g/m3之间,侵蚀模数在9.37~116.67g/m2之间。25°坡地柑桔林径流系数在0.079~0.378之间,径流含沙量在500~5 050 g/m3之间,侵蚀模数在48.29~1 962.04g/m2之间。在建园初期4年内,25°坡地柑桔林径流系数、径流含沙量和侵蚀模数急剧下降,径流系数由0.378下降到0.103,径流含沙量由5050 g/m3下降到350g/m3,侵蚀模数由1 962.04g/m2下降到131.42 g/m2。4年后,覆盖度的增加有效的抵消了坡度对水土流失的影响,柑桔林覆盖度达到0.82,径流系数,径流含沙量和侵蚀模数分别为0.103~0.253,350~3404 g/m3、14.71~148.4g/m2,表现出较好的水土保持效益。     

龙井市农村经济灰色关联度分析

利用灰色系统理论中灰色关联度分析的方法，龙井市近几年来农村经济分3个层次进行了系统、全面的分析。     

绵阳官司河流域水土流失综合报告

报告简述域地质地貌水文气象土壤，植被等地理因素的概况及其与土壤侵蚀的关系，指出本流域由于长防林的建立，发挥了保持水土作用，水土流失不严重，属轻度－中度侵蚀，最大侵蚀模数小于７４００［ｔ／（ｋｍ＾２．年］，全区平均侵蚀模数１７５４．４２［ｔ／ｋｍ＾２．年］；确定了水土流失类型，即片蚀，沟蚀，母质侵蚀三大类；分析了水土流失的原因：以泥岩和灰白砂岩，第四纪冰碛物堆积土侵蚀最高测定不同精植被类型的土壤质地     

Fractal dimension estimates of a fragmented landscape: sources of variability

Although often seen as a scale-independent measure, we show that the fractal dimension of the forest cover of the Cazaville Region changes with spatial scale. Sources of variability in the estimation of fractal dimensions are multiple. First, the measured phenomenon does not always show the properties of a pure fractal for all scales, but rather exhibits local self-similarity within certain scale ranges. Moreover, some sampling components such as area of sampling unit, the use of a transect in the estimation of the variability of a plane, the location, and the orientation of a transect all affect, to different degrees, the estimation of the fractal dimension. This paper assesses the relative importance of these components in the estimation of the fractal dimension of the spatial distribution of woodlots in a fragmented landscape. Results show that different sources of variability should be considered when comparing fractal dimensions from different studies or regions.     

Effects of changing spatial scale on acoustic observations of patchiness in the Gulf Stream

We examine the influence of spatial scale on studies of nektonic patchiness at the north edge of the Gulf Stream by altering the grain size of acoustic cross sections and applying a patch-finding algorithm. From original pictures of 180 pixels deep by 540–1260 pixels long, we averaged depth and length, to give 9 scales ranging from fine grain (1 m vertical × 25 m horizontal sized pixels) to coarse grain (12 m × 300 m sized pixels). Measures of overall echo intensity within patches were the most predictable and showed little change with scale. Measures of variability of the echo within patches showed simple negative trends with scale and were best measured at fine spatial scales. Patch size and shape related variables have a more complex relationship with scale with differences between day and night transects more pronounced at intermediate scales. This suggests behavioral patch forming mechanisms within the nekton occur at a specific grain size (4 m vertical × 100 m horizontal) within the Gulf Stream front.     

基于不同尺度的干旱区城市景观生态研究--以陕西榆林市为例

从区域与城市两个尺度水平 ,对毛乌素沙漠南缘的榆林市城市景观进行研究认为 :在大尺度水平上 ,区域景观生态特征对城市景观特征具有一定的控制作用 ,而城市景观强大的功能流对区域景观产生干扰作用。城市景观的空间扩展与演化 ,既受区域景观特征的影响 ,也是区域景观演化的一个有机构成部分 ;在小尺度空间上 ,景观功能区、景观斑块与廊道的格局与功能 ,对城市景观格局动态以及维持城市景观多样的生态功能具有重要意义。在不同的利益追求下形成的景观文化 ,将深刻地影响到区域与城市景观演化的方向与过程。     

乡村生态学研究的尺度与等级特征

乡村生态学 ( Village ecology)的尺度和等级特征依赖一定空间区域 ,不同尺度所研究村落的特征也不尽相同 ,空间尺度的大小很大程度上决定于所研究村落的复杂性、稳定性及特征。在特定的空间尺度下 ,乡村的组成要素随着时间尺度的变化而变化 ,但变化速率受空间尺度大小的制约。乡村生态学研究具有等级结构 ,空间尺度决定所研究单元的等级位置。行政村 (中心村 )和自然村 (自然屯 )是乡村生态学研究的基本尺度     

Spatio-temporal modelling of broad scale heterogeneity in soil moisture content: a basis for an ecologically meaningful classification of soil landscapes

We describe the classification of landscapes characterised bymineral soil using a model that calculates soil moisture availability on amonthly basis. Scotland is used as a case study area. The model uses potentialsoil moisture deficit, estimated using broad scale (40 × 40 km)climate patterns, in conjunction with meteorological station measurements toobtain finer scale values of climatic soil moisture deficit. Point estimates ofsoil available water are obtained for soil characteristics using appropriatepedotransfer functions, and geostatistical techniques are used to upscale theresults and interpolate to a 1-km grid. Known heterogeneityin soil physical characteristics is used to provide local corrections to thepotential soil moisture deficit, estimated using the climatic variables above.Temporal profiles of monthly water content are modelled for each1-km location and classified into six classes usingunsupervised cluster analysis. The spatial distribution of these classesreflects regional variations in the availability of moisture and energy, onwhich finer-grained topographic patterns are superimposed. In the case study,the broad scale spatial heterogeneity of heathlands and grasslands on mineralsoils in Scotland is shown to be strongly related to the soil moistureclassification. The results can be used in studies investigating the patternsofdistribution of communities at the landscape and regional scale.This revised version was published online in May 2005 with corrections to the Cover Date.