Nutrient addition alters drought resistance and resilience via forb abundance in a temperate grassland

Abstract

Nutrient addition has resulted in profound effects on grassland ecosystems. Yet, the response and ecological mechanisms of grassland community resistance (the ability to maintain ecosystem function during drought) and resilience (the capacity to recover after drought) in relation to nutrient addition are not fully understood. We investigated the effects of nutrient addition on resistance and resilience of a temperate grassland experiencing a drought year. Our findings demonstrated that the resistance of both the whole community and forb species decreased under nitrogen (N) addition, while only forb resistance significantly decreased under phosphorus (P) addition. Interestingly, N addition also hindered the community and forb resilience, whereas community resilience significantly enhanced under P addition. Unexpectedly, even although nutrient addition significantly affected grass biomass, grass resistance and resilience were not significantly altered by nutrient addition. Furthermore, structural equation models revealed that nutrient addition affect community drought resistance and resilience via the abundance of forb species. Our outcomes highlight the crucial function of forb in sustaining grassland community stability in the face of global change. It provides crucial scientific evidence for the scientific management and sustainable preservation of ecosystem services in grassland ecosystems under global change.