Soil chemical properties and phytodiversity of riparian forest land near Nanwan Lake

Abstract

The riparian zone of reservoir is a spatially fluctuating ecotone (between terrestrial and aquatic ecosystems) and is an important area for nutrients’ circulation and materials’ flow. Riparian forest plays an important role in the stability of riparian habitat. As yet, the relationship between soil chemical properties and biodiversity of riparian forest near reservoir has not been thoroughly elaborated. In this study, we analyzed the soil chemical properties (total nitrogen and carbon, available phosphorous and kalium) and community structure characteristics of trees (diameter at breast height, tree height, canopy width), shrubs and herbaceous (Shannon diversity index, Simpson dominance index, species richness index, Pielou uniformity index) in the riparian forest land at the tail section that is a part of Nanwan lake reservoir in China. Results showed that the structure of riparian forest near reservoir of Nanwan lake represents a stable community. There was no significant difference in soil chemical properties and vegetation biodiversity between the type of centre’s island and the type of peninsula. The range of the nutrients’ content in forest land (nеar Nanwan lake reservoir), respectively, is: total carbon (TC) – 7,8–19,5 g/kg, total nitrogen (TN) – 0,72–1,49 g/kg, available phosphorous (AP) – 1,89–3,83 mg/kg, available kalium (AK) – 48,0–100,5 mg/kg. The soil pH value of the riparian forest land near Nanwan Lake reservoir is low due to strong acid reaction, so the toxic effects of aluminum should be considered. In the RDA analysis, the first axis is explained 73,16% of the biodiversity factors of trees, shrubs and herbaceous, and the second axis – 6,48%. The reflection of the presence of shrub-herbaceous layer in the values of the chemical properties of soil is significant: this layer is an important source of soil organic matter in the coastal zone and has a positive effect on soil quality. Therefore, attention should be paid to maintaining the stability of community structure in understory shrub-herbaceous layer.