Function diversity of soil fungal community has little exclusive effects on the response of aboveground plant production to experimental warming in alpine grasslands

Abstract

We performed a long-term warming experiment in three alpine grassland sites (i.e., site A, B and C with an elevation of 4313, 4513 and 4693 m, respectively) of the Northern Tibetan Plateau since 2010. Aboveground plant production (i.e., normalized difference vegetation index, NDVI; soil adjusted vegetation index, SAVI and aboveground biomass, AGB) and soil fungal function at the 0–10 cm depth were examined in 2017 and 2018. The ITS high-throughout sequencing technology was used to obtain soil fungal community and then the FUNGuild tool was used to obtain soil fungal function. Experimental warming significantly reduced NDVI, SAVI and AGB by 27.92%, 27.80% and 14.78% at the site A in 2017, respectively. Experimental warming significantly increased the number of trophic model by 41.18% in 2017 and Simpson index at the trophic model level by 46.40% in 2018 at site B. Experimental warming significantly increased the number of guilds by 63.46% and 28.28%, and Shannon index at the guild level by 24.11% and 85.51% at site A and B in 2017, respectively. Experimental warming did not significantly affect the β-diversity of soil fungal function. Aboveground plant production increased significantly with increasing environmental moisture, ammonium nitrogen and the β-diversity of soil fungal function at the guild level, but decreased significantly with increasing environmental temperature and soil pH. The α- and β-diversity of soil fungal function had confounded effects with other factors (i.e. environmental temperature and moisture, soil ammonium and nitrate nitrogen, available phosphorus and pH) on aboveground plant production. In contrast, the exclusive effects of α- and β-diversity of soil fungal function on aboveground plant production was minimal and even negligible. Therefore, soil fungal function had negligible exclusive effects on the response of aboveground plant production to experimental warming in alpine grasslands, Northern Tibet.