Nutrient addition alters community stability via changing stability of functional groups in a temperate grassland

Nitrogen (N) and phosphorus (P) additions have led to profound impacts on grassland ecosystems. However, there is currently limited understanding of the response and underlying ecological mechanisms of the grassland ecosystem stability, particularly in relation to nutrient inputs and their impact on resistance and resilience. We conducted the influence of N and P inputs on resistance and resilience in a temperate grassland during a natural severe drought. Our results demonstrated that N addition considerably decreased the resistance of both the community and forb, while P addition only decreased forb resistance. Interestingly, N addition also hindered the resilience capacity of the community and forb, whereas P addition enhanced the community resilience. Surprisingly, neither N nor P addition had a discernible impact on the resistance and resilience of grasses. Nutrient inputs alter community stability via changing the stability of functional groups. Our findings highlight the crucial function of forbs in sustaining grassland ecosystem stability under climate change. Moreover, it delivers fundamental supports for the scientific management and sustainable preservation of ecosystem services in grassland ecosystems under global change.