关键词: 玉米株型, 根系分布

Abstract: Revealing the relationship between distribution pattern of liverworts community and environmental factors is an important step for biodiversity conservation in Tiankeng cave. Multivariate regression trees analysis, α and β-diversity analysis, and canonical correspondence analysis were conducted to analyze the distribution patterns of liverwort communities in four caves with different depths in Monkey-Ear Tiankeng, Guizhou Province and their relationships with environmental factors. The results showed that the community composition of liverworts was simple in Tiankeng caves, mainly consisting of one or two dominant species. Species richness of liverwort community increased with the increasing depth of cave location, showing a gradient pattern. The liverwort communities could be divided into three types from four caves using cross-validation: (Ⅰ) Communities of middle-depth cave, mainly consisting of Cyathodium smaragdinum+Pellia endiviifolia+Riccia fluitans; (Ⅱ) Communities of lower middle depth cave, mainly consisting of Cyathodium smaragdinum+Riccia fluitans; (Ⅲ) Communities of bottom cave, mainly including Pelliaendiviifolia+Conocephalum japonicum+Dumortiera hirsuta. In horizontal direction, the diversity of liverwort community changed with community composition (species, genera, and families) in the Wanmutitian cave, which was first increased and then declined. However, the environmental heterogeneity of communities showed a contrasting pattern. The diversity of liverworts was consistent with the environmental heterogeneity in the Tianletang cave, which was first decreased and then increased. The distributions of liverwort community in both vertical and horizontal directions were affected by the gradient variations of temperature, humidity, and illumination. The diversity of liverwort community was a result of the combinations of three environmental factors. The interpretation of axis 1 and axis 2 was 45.89% and 79.28% from canonical correspondence analysis, respectively.

Key words: Maize plant type, Roots distribution