Response of the soil bacterial community to reciprocal soil translocation along an elevation and temperature landscape gradient

Abstract

Soil microbial communities play a central role in soil biogeochemical processes, yet few studies have addressed their response to climate change in semi-arid savannah ecosystems. In this research, we reciprocally translocated soils along an elevational gradient: south subtropical zone (SS) and mid-temperature zone (MT) in a dry-hot valley of Southwest China to simulate temperature and moisture changes under climate-change scenarios. Our objective was to gain a mechanistic understanding of the responses of bacterial communities and soil respiration accompanying climate change. Over a 13-month experiment, soil samples were collected in three main seasons (winter, spring and summer), and the bacterial community diversity, composition and soil basal respiration were determined. The results showed that soil origin and sampling season greatly affected soil bacterial Shannon index, bacterial community structure and soil basal respiration in this region (P< 0.05). The bacterial community compositions in the translocated soils became more similar to the soil bacterial communities in their new environments. Soil temperature and moisture were significantly correlated with the bacterial community structure (P < 0.01), and they could explain 30.86% and 35.85% of the total variances of bacterial community compositions for SS and MT soils, respectively. Relative abundances of dominant bacterial groups were significantly (P < 0.05) correlated with soil temperature ‒ warming increased the relative abundances of Proteobacteria and Bacteroidetes, whereas cooling had the opposite effect. This research provides useful information as to how climate warming and cooling may alter soil bacterial communities in semi-arid savannah ecosystems.