漓江水陆交错带不同植被类型及其土壤养分变异规律

Variation patterns of different vegetation types and soil nutrients in water-land ecotone of the Li River

关键词:  植被类型, 植物物种多样性, 土壤养分, 水陆交错带, 漓江

Key words:  vegetation type, plant species diversity, soil nutrient, water-land ecotone, the Li River

摘要:

为促进水陆交错带生态系统恢复与重建,在典型样地调查的基础上,采用Pearson 相关系数法和冗余分析法研究了漓江水陆交错带不同植被类型下的植被物种组成及多样性、土壤养分的变异规律。结果表明:(1)不同植被类型(砾石滩、草地、灌草地和疏林地)的植物群落结构及物种多样性均有显著差异。随着水淹时间的减少,水陆交错带由分布零星草本植物群落逐渐演变为草、灌、乔植物群落,植被物种α多样性(Shannon-Wiener指数、Pielou指数和Simpson指数)和植被覆盖度呈逐渐增加趋势,在砾石滩最低,在疏林地最高。(2)不同植被类型的土壤养分含量有显著差异。随水淹时间的减少,土壤有机质含量逐渐增加,而土壤含水量、有效氮、有效磷和速效钾呈先上升后下降趋势,以上养分含量最大值多出现在灌草地或疏林地,在草地次之,在砾石滩最低。(3)相关性及冗余分析得出土壤有效氮、速效钾、有效磷和有机质与植被物种α多样性各指标呈极显著正相关,其中土壤有效氮和速效钾与植被物种多样性的关联性最强。综上认为,漓江水陆交错带不同植被类型下植被物种组成及多样性、土壤养分具有异质性分配格局,适度水淹有利于植被群落聚集,对土壤养分积累有一定促进作用; 草本植物对适度水淹环境的适应能力更强; 漓江水陆交错带生态修复过程中需针对性设计不同植被类型区域的修复方案,并充分考虑植被物种多样性与土壤有效养分之间的关系。

Abstract:

To promote the restoration and reconstruction of ecosystem in the water-land ecotone, based on typical sample investigation, the variation patterns of vegetation species composition and diversity, and soil nutrients under different vegetation types were studied using Pearson correlation coefficient method and redundancy analysis method. The results were as follows:(1)There were significant differences in plant community structure and species diversity of different vegetation types(gravel zone, grass zone, shrub-grass zone, tree zone). As the submersed duration decreased, the water-land ecotone gradually evolved from scattered herbaceous plant communities to grass, shrub, and tree plant communities, and the α diversity of vegetation species(Shannon-Wiener index, Pielou index and Simpson index )and vegetation coverage showed a gradually increasing trend, which were lowest value on the gravel zone and the highest on the tree zone.(2)There were significant differences in soil nutrient content among different vegetation types. With the decrease of submersed duration, soil organic matter content gradually increased, while soil water content, available nitrogen, available phosphorus, and available potassium showed a trend of first increasing and then decreasing, the maximum values of these nutrients mostly occurred in shrub-grass zone or tree zone, followed by grass zone, and gravel zone was the lowest.(3)Correlation and redundancy analysis showed that soil available nitrogen, available potassium, available phosphorus and organic matter were significantly positively correlated with various indicators of vegetation species α diversity, among which soil available nitrogen and available potassium had the strongest correlation with vegetation species diversity. In conclusion, different vegetation types in the Li River water-land ecotone have heterogeneous patterns of vegetation species composition and diversity as well as soil nutrients. Moderate submergence is beneficial for vegetation community aggregation and promoting soil nutrient accumulation. Herbaceous plants have stronger adaptability to moderate submergence environments. During the ecological restoration process of the Li River water-land ecotone, it is necessary to design restoration plans for different vegetation types and fully consider the relationship between vegetation species diversity and soil available nutrients.