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51.
林桂娜 《农业图书情报学刊》2006,18(11):152-153,170
针对现代舞、交际舞、体育舞蹈等类图书归类时出现的归类混乱的问题进行了详细分析,指出了《中图法》四版在此类类目设置的不足之处,并提出了解决问题的办法。 相似文献
52.
松嫩平原羊草草地水淹干扰恢复过程的群落动态 总被引:16,自引:6,他引:10
根据随机取样的测定数据,经过幂函数和多元回归分析及相关检验,揭示了草地水淹干扰对羊草 寸草苔、羊草 杂类草群范数量性状的变化规律。水淹干扰对草地植被的物种组成及其比例有明显的影响。水淹后基本恢复到正常草地的种类数量和生产量配置大约需要6—7年。随着生境水分减少和土壤变干,羊草种群的数量和生物量均以幂函数形式增加,而寸草苔和杂类草的数量和生物量则呈先增后降的变化过程。 相似文献
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54.
Change in spatial characteristics of forest openings in the Klamath Mountains of northwestern California,USA 总被引:4,自引:0,他引:4
Carl N. Skinner 《Landscape Ecology》1995,10(4):219-228
Change in the spatial characteristics of forest openings was investigated in three forested watersheds in north-western Siskiyou County, California totalling approximately 24,600 hectares. Watersheds with minimal human disturbance were chosen for study. However, fire suppression has been pervasive throughout. Characteristics of forest openings (area, perimeter, distance between neighboring openings) were measured on aerial photographs taken 41 years apart. An index of regional form was determined for the landscape. Shape complexity for each opening was calculated using two indices based upon fractals. Significant differences were found using the Kolmogorov-Smirnov two-sample test between the perimeters, areas, distance from sample point to nearest opening, and distance between neighboring openings. The perimeters and areas became smaller, and the distances from the sample point to the nearest opening and between neighboring openings became greater over the 41 years between aerial photo sets. The estimated area occupied by openings decreased from 25.8 % to 15.6 % of the study area. No significant difference was found in the shape of the openings except as the shape indices were influenced by changes in size of the openings.This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain and not subject to copyright. 相似文献
55.
Landscape-ecological mapping of the Netherlands 总被引:1,自引:0,他引:1
Kees J. Canters Cees P. den Herder Aart A. de Veer Paul W. M. Veelenturf Rein W. de Waal 《Landscape Ecology》1991,5(3):145-162
The Landscape-ecological Mapping of the Netherlands project (LMN project) started in 1983 with the aim of establishing a landscape-ecological database for use in developing and evaluating national land-use plans. The project, working with grid cells of 1 km2, has four working objectives: a) development of mapping potential for basic landscape-ecological data, b) assessment of susceptibility to interventions, c) evaluation of significance for nature conservation and d) production of vulnerability maps, as a combination of susceptibility and significance. In addition to information on soil, groundwater, ecotopes, flora and fauna, the database also incorporates information on physiographical features and entire landscapes. The resulting database is a geographic information system (GIS). This article describes the second phase of the project (1985–1989), covering the Randstad area, and focusses on the methods and the applications potential of the database. 相似文献
56.
A review of models of landscape change 总被引:23,自引:1,他引:22
William L. Baker 《Landscape Ecology》1989,2(2):111-133
Models of landscape change may serve a variety of purposes, from exploring the interaction of natural processes to evaluating proposed management treatments. These models can be categorized as either whole landscape models, distributional landscape models, or spatial landscape models, depending on the amount of detail included in the models. Distributional models, while widely used, exclude spatial detail important for most landscape ecological research. Spatial models require substantial data, now more readily available, via remote sensing, and more easily manipulated, in geographical information systems. In spite of these technical advances, spatial modelling is poorly developed, largely because landscape change itself is poorly understood.To facilitate further development of landscape models I suggest (1) empirical multivariate studies of landscape change, (2) modelling of individual landscape processes, (3) explicit study of the effect of model scale on model behavior, and (4) scaling-up results of studies, on smaller land areas, that have landscape relevance. 相似文献
57.
The relationship between fine-scale spatial patterns of forage abundance and the feeding patterns of large ungulates is not well known. We compared these patterns for areas grazed in winter by elk and bison in a sagebrush-grassland landscape in northern Yellowstone National Park. At a fine scale, the spatial distribution of mapped feeding stations in 30 m × 30 m sites was found to be random where there were no large patches devoid of vegetation. In areas similar to the mapped sites, the underlying spatial distribution pattern of biomass was also determined to be random. At a broad scale, forage biomass differed among communities across the northern range but forage quality did not. These results suggest that ungulates are feeding randomly within forage patches (fine scale) but may select feeding sites based upon forage abundance at broader, landscape scales. Contrary to what has been suggested in other systems, ungulates were not overmatching at finer scales. 相似文献
58.
Functional brain alterations induced by lindane were examined in Rat chronically exposed to low doses of lindane (1 and 2 μg L−1 in drinking water) from conception. Histological and electrophysiological investigations were conducted at 14 weeks of age. Lindane did not induce histological changes. It did not significantly modify the sleep-wakefulness cycle and EEG did not show major alterations. The spectral EEG analysis, by recording cortical variations in both energy spectrum and energy levels of different frequency bands, showed an increase in the 11-15 Hz activity in both groups exposed to lindane. This activity was characterised by spindles well-depicted during slow wave sleep or associated with fast activity during wakefulness and theta activity in paradoxical sleep. These data suggest that chronic exposure to lindane doses as low as 1 μg L−1 in drinking water could lead to central electrophysiological effects possibly involving GABA-benzodiazepine mechanisms. 相似文献
59.
60.
阐释了园林构成要素中的必然性要素和偶然性要素及其相互关系与运用意义;以昆明世博园中“齐鲁园”为例,辩识了“齐鲁园”中必然性与偶然性园林要素,分析了诸要素在特定园林环境布局中的运用。 相似文献