竹容器内における原生生物群集の動的構造
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概要
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The canes cut from the bamboos three months affer budding, are arranged in the campus of the Tohoku University, filled with tap-water, and in a few days, the protister community begins to appear at the bottoms of them. This community changes successively into the others with the lapse of time. The benthonic protister was sampled from the containers every three days from July to September of 1953. At first, to clarify the changes of the numerical compositions of the so-called sere in the successive course, the correlation coefficient between the individual number of each species in one catch and that of corresponding species in the following next catch was calcurated (Fig.1). From such a statistical treatment, it was known that this course is characterized by the changeable composition in late July, and also by the unchangeable one in early July and August. In September, however, these two compositions are found. The structures of the communities in the five periods as given above were examined quantitatively from the following view points.1) Both the kind and individual number of the constituent species, and the community-size which may be indicated by the logarithmic number of the dominant species. 2) The distribution in the relative number of the constituent species. As to the quantitative estimation of the latter. "Index of numerical distribution" induced from the LORENZ-curve, which is frequently applied in the economic statistics, is first used. When cummulative percentage of the estimated number of species is represented in abscissa, and also that of individual numbers is in ordinate according to the rank in number, various lines are obtainable. In this case, when the species number is equal to the estimated one, and also the individual number is equal in every species, the straight line, ORQ in figure 2,is obtained. When the numerical distribution is not equal or the species number is less than the estimated one, the curve, OMQ in the same figure, is given. Thus, it is known that the area enclosed with such straight line and curve as mentioned above is determined in accordance with the state of the numerical distribution, and also the number of constituent species. In a community comprised of only one species, the area reaches the maximum and remains constant. Thus, the distribution of the relative number can be estimated quantitatively from the ratio of the area in a given community to that in the community just mentioned. The writer designates this ratio as "Index of numerical distribution". When the communities found in the five periods are examined by the form of histogram of these attributes, it is noticed that they are characterized by the following definite structures : 1) The communities found in early July, viz., group A, which may correspond to the pioneer community, mainly comprise Heteromita. They incline to maintain the constancy in "Index of distribution", but the community-size changes gradually with the lapse of time, 2) In late July, the communities, viz., group B. show a changeable value not only in "Index of distribution" but also in the size of the community. Glaucoma and Chlamydomonas are important species in these communities. 3) The communities in August are composed of the two groups, viz., group C_1 and group C_2,which are characterized by different structures. The former shows a large value to some extent in "Index of distridution" and in the community-size comparing with the group C_2. The group C_1 precedes the other. These groups are composed of Chlamydomonas and Cercomonas, of which the former is considered as the dominant species and the latter the subordinant. 4) In Septemder, the communities with a stable composition, viz., group D, present the same structure as group C_2. However, in the communities characterized by a changeable composition, viz., group E, the value of "Index of distribution" is lowest and changeable. The community-size is rather smaller than the other. Chlamydomonas, C
- 日本生態学会の論文
- 1956-01-31