Biodiv Sci ›› 2024, Vol. 32 ›› Issue (5): 23483.  DOI: 10.17520/biods.2023483  cstr: 32101.14.biods.2023483

• Original Papers: Animal Diversity • Previous Articles     Next Articles

Short-term effects of warming and wetting on the soil nematode communities in the alpine meadow

Zhu Yao, Xue Wei(), Jinhao Ma(), Xiao Ren(), Yuying Wang(), Lei Hu(), Pengfei Wu*()()   

  1. College of Grassland Resource, Southwest Minzu University, Chengdu 610225
  • Received:2023-12-23 Accepted:2024-03-17 Online:2024-05-20 Published:2024-04-29
  • Contact: E-mail: wupf@swun.edu.cn

Abstract:

Aim: Since the late 1980s, the climate on the Qinghai-Tibetan Plateau has become warm and humid. Soil nematodes are highly sensitive to environmental changes and used broadly as bioindicators to reflect habitat change. The aim of this study is to assess the effects of climate warming and increased precipitation on the structure and ecological dynamics of soil food webs in alpine meadows situated on the eastern edge of the Qinghai-Tibetan Plateau.

Method: Four distinct treatments were implemented in an alpine meadow located in Northwest Sichuan in May 2020. These modifications involved increasing precipitation by 50% (P50), increasing local temperature by 2℃ (T2), increasing both precipitation by 50% and local temperature by 2℃ (P50+T2), or a natural alpine meadow with no environmental alteration (CK). The investigations were conducted on taxonomic composition, density, diversity and trophic groups of soil nematode communities, coverage and species richness of plant communities, and soil properties in the plots of each treatment in September 2022. Different treatment effects on the soil nematode communities were analysed by One-way ANOVA and t-test, and the redundancy analysis and correlation analysis were employed to explore the relationships between nematode communities and soil properties as well as the characteristics of plant communities.

Results: The findings revealed: (1) The density and diversity of nematode communities treated with P50 showed an increasing trend. A total of 37 genera of nematodes, including Helicotylenchus and Diplogsteroides, were eradicated from T2 treatment. This led to a significant decrease in the density, taxonomic richness and Shannon diversity of the local soil nematode community while showing a significant increase in the Simpson dominance index. The density of nematode communities increased significantly in the 0-10 cm soil layer and decreased significantly in the 10-20 cm layer of P50+T2 treatment. (2) The density of fungivores, plant-parasites and predators-omnivores was increased in the 0-10 cm soil layer of P50 treatment but was reduced for bacterivores. In the T2 treatment, the density of each trophic group nematodes in 0-10 cm soil layer was decreased. Additionally, the restrain effect of warming was weaker on the bacterivores and fungivores compared to the plant parasites and predators-omnivores, which resulted in an overall increased relative density (or individual percentage) of bacterivores and fungivores. Notably, the P50+T2 treatment significantly elevated the density of fungivores in the 0-10 cm layer and reduced the density of bacterivores and plant-parasites in the 10-20 cm layer. (3) The density and diversity of nematode communities were positively correlated with soil moisture and plant coverage, and were negatively correlated with the content of nitrate nitrogen.

Conclusion: This study underscores the varied responses of soil nematodes to precipitation and temperature fluctuations, with the density and diversity of soil nematode communities in the topsoil layer being suppressed by two-year warming but promoted by the increased precipitation, or simultaneous increments of precipitation and temperature.

Key words: warming, increase precipitation, soil nematodes, diversity, trophic groups, alpine meadow