Artificial Reseeding Promotes Biodiversity Restoration in Alpine Sandy Meadow of the Eastern Qinghai-Tibet Plateau

Alpine grasslands have undergone severe desertification due to climate warming and overgrazing. Artificial reseeding has been widely employed for the restoration of these alpine sandy grasslands. However, its effectiveness in enhancing biodiversity remains unclear, particularly regarding the consistency of responses between aboveground plant diversity and belowground microbial diversity. To investigate the impacts of artificial reseeding on plant and microbial diversity of sandy meadows, we conducted field investigations in alpine grasslands of the eastern Qinghai-Tibet Plateau that had undergone artificial reseeding, natural restoration, or remained as sandy meadows. The findings revealed that artificial reseeding yields inconsistent restoration outcomes for aboveground plant communities and belowground soil microbial communities in sandy meadows, thereby altering the typical relationships between above- and belowground biodiversity. Artificial reseeding significantly promoted plant diversity in sandy meadows, with the Shannon-Wiener index of restored meadow communities increased by 67% (p < 0.01), while its impact on restoring soil microbial diversity was less pronounced. Introducing new plant species through reseeding improved vegetation cover, plant diversity, and fungal richness. In addition, artificial reseeding altered soil properties, reducing soil pH by 0.35 units and altering soil nutrient content, which in turn influenced the composition and structure of plant and microbial communities. These results have essential implications for regional ecological security and the sustainable development of alpine meadows.