QUANTITATIVE-ANALYSIS OF SHOOT PHENOLOGY AND DOMINANCE IN HERBACEOUS VEGETATION
QUANTITATIVE-ANALYSIS OF SHOOT PHENOLOGY AND DOMINANCE IN HERBACEOUS VEGETATION
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DOI：
10.2307/2259378
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发表时间：
1977-01-01
影响因子：
5.5
通讯作者：
BAND, SR
中科院分区：
文献类型：
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作者：
ALMUFTI, MM;SYDES, CL;BAND, SR
在现存量和凋落物的变化进行了测量季节性采样和排序的草本植被在13个站点在谢菲尔德[英国]地区。研究的植被类型包括高草本，林地和草地群落。在每个站点，在4-10个重复的0.25平方米的样方的生活部分被分成其组件和图表绘制显示更常见的物种的芽物候。在草本植被生长在肥沃、相对不受干扰的条件下的地点，夏季的现存量达到一个大的高峰（> 400克/平方米干重），植被中的物种很少。这些地点的低物种密度与某些物种行使竞争优势的能力有关，这种现象涉及6月至8月期间密集的叶冠迅速扩张，再加上高密度的持久性凋落物的产生。在林地和草地的网站检查，最大的现存量和凋落物的总和不超过800克/平方米和各种植物物候遇到。在其中2个林地地点，春季物种很突出;这些植物表现出芽生长的截短期，这是在树冠完全扩张之前，紧接着早春枯枝落叶密度显着下降。在该网站的现存作物受到严重限制，土壤肥力低，最常见的物候模式是万年青植物，在某些这些物种，没有季节性高峰的枝条扩张可以检测到。在2的石灰石草原调查，杂类草与仲夏高峰期的拍摄扩展是突出的，这些植物中的大多数有相对较深的根系，并出现利用储备的水分期间，许多草受到干燥。结果的一个一致的特点是显着的幅度的季节变化的丰富的britonites，扩大的春季和秋季的潮湿凉爽的条件相吻合。对草本植被的物种密度进行了研究。潜在的高物种密度大约相当于350-750克/平方米的最大现存作物和凋落物的阳光范围。
Variation in standing crop and in litter was measured by seasonal sampling and sorting of the herbaceous vegetation at 13 sites in the Sheffield [United Kingdom] region. The vegetation types examined comprised tall herb, woodland floor and grassland communities. At each site the living fraction in 4-10 replicated 0.25 m2 quadrats was separated into its components and graphs were plotted showing the shoot phenology of the more common species. At the sites in which herbaceous vegetation was growing under fertile, relatively undisturbed conditions, there was a large peak in standing crop during the summer (> 400 g/m2 dry wt), and the vegetation contained few species. The low species-densities at these sites was related to the ability of certain species to exercise competitive dominance, a phenomenon involving the rapid expansion of a dense leaf canopy during the period June-Aug., coupled with the production of a high density of persistent litter. In the woodland and grassland sites examined, the sum of the maximum standing crop and the litter did not exceed 800 g/m2 and a variety of plant phenologies was encountered. At 2 of the woodland sites vernal species were prominent; these plants exhibited truncated periods of shoot growth, which preceded full expansion of the tree canopy and followed immediately the marked decline in density of tree litter in early spring. At the sites where the standing crop was severely restricted by low soil fertility, the commonest phenological pattern was that of the evergreen; in certain of these species, no seasonal peak of shoot expansion could be detected. In 2 of the limestone grasslands investigated, forbs with mid-summer peaks of shoot expansion were prominent; the majority of these plants had relatively deep root-systems and appeared to exploit reserves of moisture during periods when many grasses were subjected to desiccation. A consistent feature of the results was the marked amplitude of seasonal variation in the abundance of bryophytes, expansion of which coincided with the moist cool conditions of spring and autumn. The species-density in herbaceous vegetation was studied. The potential for high species-density corresponds approximately to the range of 350-750 g/m2 in the sun of maximum standing crop and litter.