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

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.