Improvement, Comparison, and Application of Field Measurement Methods for Grassland Vegetation Fract

来源 :植物学报 | 被引量 : 0次 | 上传用户:jch26
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
As one of the important vegetation parameters, vegetation fractional coverage (VFC) is more difficult to measure accurately among a good many parameters of plant communities. The temperate typical steppe in the north of China was chosen for investigation in the present study and a digital camera was used to measure herb community coverage in the field, adopting methods of ocular estimation, gridding measurement, visual interpretation, supervised classification, and information extraction of color spatial transformation to calculate the VFC of images captured by the digital camera. In addition VFC calculated by various methods was analyzed and compared VFC, enabling us to propose an effective method for measuring VFC using a digital camera. The results of the present study indicate that: (i) as two common useful and effective methods of measuring VFC with a digital camera, not only does the error of estimated values of visual estimation and supervised classification vary considerably, but the degree of automatization is very low and depends, to a great extent, on the manipulator; (ii) although the method of visual interpretation may assure the precision of the calculated VFC and enable the precision of results obtained using other methods to be determined, as far as large quantities of data are concerned, this method has the disadvantages of wasting time and energy, and the applications of this method are limited; (iii) the precision and stability of VFC calculated using the grid and node method are superior to those of visual estimation and supervised classification and inferior to those of visual interpretation, but, as for visual interpretation and supervised classification, gridding measurements are difficult to apply in practice because they are not time efficient;and (iv) in terms of the precision of calculation of the VFC, an information-extracting model based on an intensity, hue, saturation (IHS) color space-multi-component series segmentation strategy is superior to methods of ocular estimation, gridding measurement, and supervised classification. In terms of practical efficiency, the information-extracting model is superior to visual interpretation, supervised classification,and gridding measurement. It has been proven that estimating the VFC of the north temperate typical steppe using this model is feasible. This is very fundamental research work in grassland ecology.
其他文献
目前,我国的社会经济发展较快,与此同时,也促进了电力系统的发展水平。在电力系统中,10kV配电线路作为重要的组成部分,其正常运行关系着用电安全。因此,本文主要分析了10kv配电线路
法国政治题材动画片《我在伊朗长大》,将伊朗残酷的战争与严苛的社会环境都融化在一个小姑娘的成长过程中,具有震撼人心的力量.从中我们应当反思,为何中国历史上的政治题材动
The reaction of Ni(CH3COO)2·4H2O, Na2MoO4·H2O, MoO3, 1,10-phenanthroline and 1,4-butylenediphosphonic acid in distilled water at 180 ℃ for 72 h produced two
A novel compound PMPP-SAL (1-phenyl-3-methyl-4-(salicylidene hydrazide)-propenylidene-pyrazolone-5) has been synthesized and characterized by elemental analysis
A small oscillogram, one end of which was substituted by a bright point caused by the redox of an appropriate depolarizer and the other end of which was the red
The seed germination and seedling growth of pakchoi (Brassica campestris ssp. chinensis var.communis Tsen et Lee cv. Hanxiao) were not significantly inhibited u
建筑供配电系统的可靠性、灵敏性和安全性,直接关系到人身安全以及造成难以估计的经济损失,因此,供配电系统在电气设计时是重要的一环。尤其是在内部建筑的低压供配电系统设计更
The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the dis
Randomly amplified polymorphic DNA (RAPD) analysis was used to investigate the genetic variation among populations, between populations, and within populations,
Phytoremediation has gained increased attention as a cost-effective method for the remediation of heavy metal-contaminated sites. Because some plants possess a