The correlation and niche of survival community of Kengyilia thoroldiana in Maduo County, Qinghai Province

The soil concentration gradients of 12 common plant species and 66 species pairs from Maduo County, Qinghai Province were determined using χ² tests, correlation analysis, niche breadths, and niche overlaps in order investigate the correlations between niches and species and to further our understanding of the ecology of the rare Kengyilia thoroldiana plant. The results showed that: 1) The common characteristics of common species in the community were not significantly negatively correlated and were independent of each other. The positive-negative correlation ratios found in the χ² test, Pearson’s correlation coefficient test, and Spearman’s rank correlation coefficient test (1.06, 1.10, and 0.97, respectively) were roughly equal to one. Therefore, the community may be in a relatively stable transitional stage in terms of vegetation succession. 2) There were no significant relationships between K. thoroldiana and other common plants. The Spearman’s rank correlation coefficients showed insignificant positive correlations with five plants, such as Poa annua, and insignificant negative correlations with six plants, such as Leontopodium leontopodioides. 3) K. thoroldiana showed wide niche breadth and large niche overlap under the six soil factor gradients, and had strong ecological adaptability and a competitive advantage. 4) Among the 66 species pairs, the pairs with stronger positive correlations showed relatively large niche overlap in every soil factor gradient. Nevertheless, the pairs with stronger negative correlations showed niche overlap only in certain soil factor gradients and did not possess as strong positive correlations in terms of overall overlap. In the future, human damage to K. thoroldiana populations should be reduced in order to ensure the natural succession of the community and to ensure the sustainability of the genus’ germplasm resources.