Higher Vulnerability of Heterotrophic Soil Respiration to Temperature Drop in Fallows than in Meadows

Abstract

The present study examines the difference between stability and climatic factors of soil microbial communities in two ecosystem types with similar plant biomass, while differing in plant diversity, successional stage and complexity. Observations of variation in stability can be applied to climate change investigations, a topic of current pivotal importance. We compared responses of soil basal respiration to short time perturbation in soils collected from six established (meadow) and six early successional (fallow) ecosystems by exposing them to thermal and water stress. Resistance and resilience indices were calculated to describe how much a system was affected by and recovered from perturbation. The soil’s physico-chemical properties and plant community composition were identified and used for correlation and regression analyses with the stability indices. There was a smaller relative change in soil respiration in meadows than in fallows as temperature decreased from 22 to 10°C. Resistance to coolness was correlated to higher soil pH, while resilience to plant species richness. The drying-rewetting experiment highlighted that the stability indices became non-linear when a data set had high variations. Soil microbial communities in a more complex and mature ecosystem type (meadow) were more stable under a moderate perturbation. This might have been supported by co-occurring factors, with soil pH being the most influential. The slightly acidic fallow soil might have a higher potential for carbon sequestration than neutral meadow soil.