Subjects: Biology >> Botany >> Applied botany submitted time 2022-07-05 Cooperative journals: 《广西植物》
Abstract： In order to analyze the variation characteristics and the effect of microhabitat on leaf functional traits of woody plants in Tiankeng. Shenmu Tiankeng is a typical karst Tiankeng in Dashiwei Tiankeng Group in Guangxi, and there is a well-preserved underground forest that is easily accessible. Ten leaf functional traits (leaf thickness, leaf tissue density, leaf area, etc.) were selected to study woody plants in different microhabitats (bottom, waist, and edge) of Shenmu Tiankeng. Single-factor analysis of variance and correlation analysis were conducted to investigate the relationship between leaf functional traits in different microhabitats. The results were as follows: (1) The variable coefficient for leaf area (113.9%) was highest, while leaf carbon content was relatively stable (10.5%). (2) Ten leaf functional traits were almost no significant difference (P>0.05) for woody lianas in three different microhabitats. The leaf tissue density for trees was significantly higher at the edge and waist compared to the bottom, while the leaf potassium content for trees and shrubs, that the bottom was higher than the edge. (3) Leaf thickness was extremely significantly positively correlated with leaf area (P<0.01) at the edge of Tiankeng. The results of principal component analysis suggested that leaf tissue density (-0.833), leaf potassium content (0.782), and leaf dry matter content (-0.647) were the critical indicators for leaf functional traits of woody plants in different microhabitats of Shenmu Tiankeng. This study demonstrate that different growth types of woody plants can adapt to the three microhabitats of Tiankeng via the trade-off of leaf functional traits. This study is expected to provide theoretical guidance for the protection of Tiankeng vegetation.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-06-07 Cooperative journals: 《广西植物》
Abstract： The distribution characteristics and internal links of soil enzyme activities, nutrient content and woody plant diversity in negative topographic habitats of Tiankeng were studied, which provided a theoretical basis for the protection and reconstruction of plant resources in karst areas. The Tiankeng forests of the Dashiwei Tiankeng group in Guangxi were selected as the object. Based on the community diversity survey and soil habitat survey from the inner and top area to the outer area of Tiankeng, the relationship between species diversity and soil factors of woody plants was explored by correlation analysis and redundancy analysis methods. The results were as follows: (1) There were 21 species, 31 genera and 20 families of woody plants in the inside area of Tiankeng, 91 species, 58 genera and 58 families of woody plants in the top area of Tiankeng, and 47 species, 30 genera and 30 families of woody plants in the outside area of Tiankeng. The Margalef index and Patrick index in the inside area of Tiankeng were significantly lower than those in the top and outside area of Tiankeng, indicating that the individuals of species increased, but the species distribution was steady; (2) The total soil nitrogen content in the outside area of Tiankeng was significantly higher than those in the top and outside area of Tiankeng. The soil total magnesium content, soil phosphorus content and soil available phosphorus content in the inside area of Tiankeng were significantly higher than those in the top and outside area of Tiankeng. The soil alkaline phosphatase content and soil urease activities in the outside area of Tiankeng were significantly higher than those in the top and inside area of Tiankeng. The soil phosphorus content in the Tiankeng was higher, but the soil enzyme activities were lower; (3) The results of Pearson correlation analysis and redundancy analysis showed that species diversity was strongly correlated with soil nutrients and soil enzyme activities. In conclusion, it can be seen that the habitats of the Tiankeng have a great influence on the species diversity, soil enzyme activity and soil nutrient content distribution characteristics. And the soil available phosphorus content, soil alkaline phosphatase activity, soil moisture content, soil urease activity, soil full magnesium content and soil total phosphorus content are the key factors affecting the species diversity of woody plants in the Tiankeng forest.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-13 Cooperative journals: 《广西植物》
Abstract： For understanding the interspecific associations of main woody plant in tiankeng forests, we choose 7 typical tiankeng forests as researched area and established a total of 18 sample plots in Dashiwei Tiankeng Group. We selected woody plants with importance values >1 as the study object, and quantitatively analyzed interspecific associations and correlations by a set of methods, namely, variance ratio, χ2 test, Pearson correlation coefficient test, Spearman rank correlation coefficient test and principal component analysis ( PCA ). The results were as follows: (1)Overall interspecific association were significant positive correlations in tree layer, non-significant, positive associations in shrub layer and significant, positive associations in community, indicating that the plant community in tiankeng forests was at a stable stage. (2)The χ2 test, Pearson correlation coefficient test and Spearman rank correlation coefficient test found that there was a difference between positive and negative correlation in tree layer and shrub layer. Many positive correlation species pairs existed in tree layer and many negative correlation species pairs existed in shrub layer, but both of them were more significantly correlation species pairs than non-significantly ones. Thus, the stability of community composition in tree layer was higher than shrub layer. And, there was a strong competition and cooperation between species pairs in tree layer, a strong competition and repulsion between species pairs in shrub layer, and a close interspecific association in community. (3)According to the results of PCA, the 24 main woody species were divided into four ecological species groups. The tiankeng forests community distribution was in a circle distribution pattern from the bottom to the top of the tiankeng topography, which was affected by environmental differences and species characteristics. In conclusion, these results suggest that the close interspecific association may be one of the maintenance mechanisms of tiankeng forest species diversity, while the self-regulation of interspecific association within the community and convergence adaptation of species to habitat heterogeneity are the basis for maintaining the stability of the community.
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