Host plants with greater ecological resistance and mutualism of arbuscular mycorrhizal fungi in degraded meadows

• AMF resistance of individual plants was higher than that of soil and mixed roots. • Degraded patches increased the AMF network complexity of soil and mixed roots. • Degradation patches alter growth-promoting AMF network patterns in host plants. The proliferation of degraded patches characterizes grassland degradation across the Tibetan alpine meadows, threatening critical ecosystem functions. Yet, how the formation of degraded patches affects the structure and functioning of arbuscular mycorrhizal (AM) fungal communities remains poorly understood. This study examined AM fungal communities across two ecological scales: whole-plant community level (soil and mixed roots) and individual host species level ( Carex moorcroftii , Kobresia humilis , and Kobresia pygmaea in the original patch; Heteropappus hispidus , Lancea tibetica , and Potentilla bifurca in the degraded patch). We specifically assessed their ecological resistance, network complexity, and network stability. We found that AM fungal communities in individual plant roots exhibited significantly greater ecological resistance than those in soil or mixed-root samples. Degraded patches increased the complexity of AM fungal co-occurrence networks within soil and mixed-roots samples but reduced the network complexity at the individual plant level. Additionally, the degradation did not impact the network stability in soil AM fungal communities, but it reduced the network stability within mixed roots and individual plant root. Notably, positive mycorrhizal growth responses were observed consistently in both original and degraded patches. Collectively, our research findings suggest that restoring degraded alpine ecosystems may require integrated approaches that simultaneously consider ecological resistance, network complexity and stability, and mycorrhizal functions.