Soil enzymatic responses to multiple environmental drivers in the Tibetan grasslands: Insights from two manipulative field experiments and a meta-analysis

Abstract

Soil enzymes are indicators of environmental changes, but uncertainties remain in predicting the impacts of environmental changes on soil enzyme activities in the cold environments. We integrated data from two manipulative field experiments and a meta-analysis in the alpine grasslands on the Tibetan Plateau. We examined the effects of multiple environmental drivers on the activities of soil extracellular enzymes involved in soil carbon (C)-, nitrogen (N)- and phosphorus (P)-cycling. The two manipulative field experiments showed that climate change (i.e., warming and altered precipitation) and nutrient (i.e., N and P) additions had no significant effects on the total, specific and ratios of soil C, N and P cycling enzyme activities in an alpine grassland ecosystem. The meta-analysis further showed no significant responses of soil enzyme activities to climate warming and nutrient additions across the Tibetan grasslands. Our findings indicate that soil extracellular enzymes are resistant to the major environmental changes in the Tibetan alpine grasslands with extreme environments. Thereby, accurate predictions of soil microbial responses to environmental changes require a thorough understanding of the soil microbial adaptation to the alpine ecosystems.