Inconsistent effects of warming and increased precipitation on ecosystem multifunctionality in an alpine meadow

Abstract

Abstract Climate change is well-known to alter the structure and function of grassland ecosystems. Warming and humidification are predicted to be the climate change trend on the Qinghai-Tibetan Plateau. However, understanding of how warming and increased precipitation affect ecosystem multifunctionality in alpine meadows is still limited. Here, we conducted an 8-year field experiment involving warming and increased precipitation in an alpine meadow to explore how warming, increased precipitation, and their interaction affect ecosystem multifunctionality through measuring plant and soil functions. The results indicated that increased precipitation, rather than warming or their interaction, had a positive effect on ecosystem multifunctionality. Warming altered the plant composition and decreased species richness, plant coverage, and plant nutrient carbon (C), nitrogen (N), and phosphorus (P) pools of sedges, but increased plant C, N, and P pools of legumes and N pools of grasses. Increased precipitation enhanced plant P pool of legumes and C, N, and P pools of grasses and aboveground community. Soil moisture and ammonium nitrogen also showed positive responses to increased precipitation. Furthermore, Pearson correlation analysis and structural equation modeling suggested that soil moisture, soil ammonium nitrogen, and plant nutrient pools jointly drove the response of ecosystem multifunctionality to increased precipitation. Our study highlighted the dominant role of precipitation in determining the influence of climate change on ecosystem multifunctionality in semi-arid alpine meadows.