Liu Jia, Fang Kai, Kou Yongping, Xia Ruixue, He Heliang, Zhao Wenqiang, Liu Qing
CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2023 Jun 25;879:163257. doi: 10.1016/j.scitotenv.2023.163257. Epub 2023 Apr 1.
The soil micro-food web is an important network of belowground trophic relationships and it participates directly and indirectly in soil ecological processes. In recent decades, the roles of the soil micro-food web in regulating ecosystem functions in grasslands and agroecosystems have received much attention. However, the variations in the soil micro-food web structure and its relationship with ecosystem functions during forest secondary succession remain unclear. In this study, we investigated how forest secondary succession affected the soil micro-food web (including soil microbes and nematodes) and soil carbon and nitrogen mineralization across a successional sequence of "grasslands - shrublands - broadleaf forests - coniferous forests" in a subalpine region of southwestern China. With forest successional development, the total soil microbial biomass and the biomass of each microbial group generally increased. The significant influences of forest succession on soil nematodes were mainly reflected in several trophic groups with high colonizer-persister values (particularly bacterivore3, herbivore5 and omnivore-predator5) that are sensitive to environmental disturbance. The increases in the connectance and nematode genus richness, diversity, and maturity index indicated an increasingly stable and complex soil micro-food web with forest succession, which was closely related to soil nutrients, particularly the soil carbon contents. Additionally, we found that the soil carbon and nitrogen mineralization rates also exhibited generally increasing trends during forest succession, which had significant positive correlations with the soil micro-food web composition and structure. The path analysis results indicated that the variances in ecosystem functions induced by forest succession were significantly determined by soil nutrients and soil microbial and nematode communities. Overall, these results suggested that forest succession enriched and stabilized the soil micro-food web and promoted ecosystem functions via the increase in soil nutrients, and the soil micro-food web played an important role in regulating ecosystem functions during forest succession.
土壤微食物网是地下营养关系的重要网络，它直接或间接地参与土壤生态过程。近几十年来，土壤微食物网在调节草地和农业生态系统生态系统功能中的作用受到了广泛关注。然而，森林次生演替过程中土壤微食物网结构的变化及其与生态系统功能的关系仍不清楚。在本研究中，我们调查了中国西南亚高山地区“草地-灌丛-阔叶林-针叶林”演替序列中森林次生演替如何影响土壤微食物网（包括土壤微生物和线虫）以及土壤碳氮矿化。随着森林演替的发展，土壤微生物总生物量和各微生物类群的生物量总体上有所增加。森林演替对土壤线虫的显著影响主要体现在几个对环境干扰敏感的高定殖-持久性值的营养类群中（特别是食细菌线虫3、食草线虫5和杂食-捕食线虫5）。连接度和线虫属丰富度、多样性及成熟度指数的增加表明，随着森林演替，土壤微食物网越来越稳定和复杂，这与土壤养分，特别是土壤碳含量密切相关。此外，我们发现森林演替过程中土壤碳氮矿化速率也总体呈上升趋势，与土壤微食物网组成和结构呈显著正相关。通径分析结果表明，森林演替引起的生态系统功能变化显著受土壤养分以及土壤微生物和线虫群落的影响。总体而言，这些结果表明森林演替通过增加土壤养分丰富并稳定了土壤微食物网，促进了生态系统功能，并且土壤微食物网在森林演替过程中调节生态系统功能方面发挥了重要作用。
