Repercussions of recovering patchy alpine meadows on soil nematode communities in the meadow ecosystems of the Yellow River source region, west China

Soil nematodes play a pivotal role in the soil food web of alpine meadows and are crucial for maintaining the integrity, functionality, and stability of this ecosystem. Alpine meadows on the Tibetan Plateau represent a significant ecosystem, where the proliferation of plateau pika population has resulted in the formation of extensive bare patches, significantly impacting the community structure of soil nematodes. However, comprehensive investigations into the mechanisms underlying natural restoration of patchy alpine meadows on soil nematodes within these meadows remain lacking. Therefore, we selected four sample plots: bare patches (BP), short-term recovery patches (SP), long-term recovery patches (LP), and healthy alpine meadows (AM) to analyze the changes in soil nematode communities at different natural successional stages in patchily degraded alpine meadows within the Yellow River source area. The results show that long-term recovery patches and healthy alpine meadows had significantly higher abundances (P < 0.05) of total, plant-feeders, bacterivorous, and omnivorous nematodes compared to bare patches and short-term recovery areas. Nematode diversity indices and nematode functional indices were consistently higher in long-term recovery patches and healthy meadows compared to bare and short-term recovery patches. The findings demonstrated that the recovery of patchy alpine meadows led to enhanced soil moisture, increased total nitrogen content and overall plant productivity, while also resulting in a reduction in soil pH. Moreover, the restoration of patchy alpine meadows exerted an influence on nematode community abundance and genus richness, exhibiting a consistent upward trend that reached its peak in healthy alpine meadows. The abundance and genus richness of nematode communities in the restored patchy alpine meadow were strongly influenced by soil moisture content and acidity, indicating that changes in soil conditions, particularly soil moisture, may contribute to the growth of nematode communities. These findings underscore the significance of natural restoration of bare patches and have important implications for the future development of sustainable grassland management strategies.