| Scutellaria tsinyunensis C. Y. Wu et S. Chow is an endangered plant species with only 1685 living individuals presently in 8 natural populations which are restricted to an scattered area from 530 to 750 m alt. in Jinyun, Beibei, Chongqing. With the helps of various statistical analyses we studied the composition, species diversity and liaison between species in the communities in which S. tsinyunensis distributed, as well as the niche, distribution pattern, modular structure of the populations. The result shows as folio wings:There are 78 species of 70 genera in 47 families of higher plants in the communities in which S. tsinyunensis distributed. Among those higher plants in the communities there are 13 species of 9 genera in 7 families of pteridophyte accounting for 16.67% of the total, 2 species of 2 genera in 2 families of gymnosperm accounting for 2.56% and 63 species of 59 genera in 38 families of angiosperm accounting for 80.77% respectively.The species diversity in the communities studied shows a tendency of increasing withthe increase of the elevation. But such tendency does not show a linear correlation. Thelowest species diversity occurs in the community IV in which Microlepia sino-strigosaChing is the dominant species, while the highest species diversity occurs in the communityI.In the communities studied, the total related differences VR are from 7.19 to 4.95, and the test statistics W are from 229.96 to 49.95, which indicates a notable positive correlation among species which have consanguineous relationships each other in the communities and the communities are in a fairy stable period.From the test of the interspecific relatedness among species in the communities we know that S. tsinyunensis present negative correlations with all the concomitance species, among which there are 8 species pairs of notably negative correlation and 51 species pairsof extremely notable negative correlation.The niche breadths of the populations of S. tsinyunensis are greatest in the communities we studied, which indicates the ecological adaptation of S. tsinyunensis is relatively stronger and the abilities of utilizing resources are greater. With the help of Pianka's niche overlap we further studied the niche overlap among different species in the sampled communities. The niche overlap among the species with the same or similar environment requirements are greater, especially nich overlap between S. tsinyunensis and those with broad niche breadths in the communities are much greater. The competition among those species like S. tsinyunensis, Dryopteris erythrosora and Veronicastrum stenostachyum etc., is intense in the communities, which may be one of the reasons why S. tsinyunensis is going to be endangered and with a very restricted distribution.The distribution patterns of the seven populations of S. tsinyunensis are clumped among the eight populations we studied, except population V of random distribution. The spatial pattern of 6 populations of S. tsinyunensis have high consistency with the negative binominal distribution, while another 2 populations, i.e., I and III are Poisson distributions. The population clumped intensities are different in different communities with a sequence as population III>VIII>VII>IV>VI> II > I . The numerical value PI has the descending trend with the increase of the elevation, viz.: 2.167 (VIII) -1.586 (III) -1.243 (VII) -1.0118 (VI) -1.0026(IV)-1.0024 (II) -1.0021 ( I ), and the distribution patterns of these populations have a diffusing trend. So the general distribution patterns of S. tsinyunensis are clumped type with a high clumped intensity. The diffusing tendency high consistency with the mathematics mode, i.e., the theoretic modes of the negative binominal distribution and Poisson distribution.S. tsinyunensis, combined with many other plants, forms diversified communities in which the individual numbers and spatial distributions of S. tsinyunensis populations are various along the environmental gradients. There are 33-442 individuals in one...
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