Plant composition diversity and community stability under vegetation succession in relation to soil aggregates

Abstract

In order to reveal the relationship between the diversity of plant composition, community stability, and soil aggregates in the process of natural vegetation restoration, and further to prevent soil erosion and improve soil quality, field survey and sampling were performed to determine vegetation characteristics and soil aggregation at different stages of vegetation succession on the Loess Plateau over the past 150 years. The results showed that there were 128 species of seed plants belonging to 39 families and 99 genera in the succession process. The dominant families were Asteraceae, Rosaceae, Gramineae, and Leguminosae, and the dominant genus was Artemisia. The plant genera in this process were characterized as monotypic genera. The plants with a high frequency of occurrence included Carex lanceolata, Lespedeza bicolor, Sophora davidii, Cotoneaster multiflorus, Artemisia caruifolia, Ostryopsis davidiana, Quercus wutaishanica, Acer tataricum subsp.ginnala, Pinus tabuliformis, Spiraea salicifolia, Aster hispidus, etc. At the genus level, the geographical composition had 11 types and 8 variants, in which the temperate geographical components had a distinguished superiority. The ratio（i.e., R/T values） of tropical（R-value） and temperate（T-value） properties decreased with increasing recovery years. The R-value correlated significantly with the R/T value, and the spread of tropical components was limited.The time series of plant diversity exhibited a single-peaked curve, with the maximum occurring between 40～70 years after restoration. The stability of the community could be ranked according to different restoration years as follows: 70 ＞ 120 ＞ 135 ＞ 150＞ 40 ＞ 10 ＞ 20 ＞ 0years. The R-value and the T-value were both significantly positively correlated with germline differentiation（i.e.,SD values） and community stability, respectively. ＞ 5mm particle size aggregates were related to the plant richness driven by tropical species, while community stability was associated with ＞0.25mm grain size clusters maintained by temperate species. As the key species to maintain community stability in the process of vegetation succession, Carex lanceolata, Lespedeza bicolor, and Sophora davidii are functional plants with the potential to increase the proportion of large-sized soil aggregates. These three species can be considered for near-natural vegetation restoration, soil quality improvement, and soil erosion control.