Slope aspect influences the resistance and resilience of soil microbial respiration to drying and rewetting in a cool-temperate forest in northern Japan

Soil microbes are key drivers of nutrient cycling in terrestrial ecosystems. It is crucial to better understand how soil microbial communities are linked to soil functions to predict the consequences of global climate change. Earlier studies have shown that the resistance and resilience of microbial respiration differed across regional or continental scales, which may be influenced by abiotic and biotic factors. However, the resistance and resilience of microbial respiration at a local scale, such as slope aspect, remain unclear. In this study, we examined the soil microbial community structure using phospholipid fatty acid (PLFA) analysis and the resistance and resilience of soil microbial respiration to drying-rewetting perturbations using soils collected from north- and south-facing slopes in a cool-temperate forest in northern Japan. Our results showed that the fungi-to-bacteria ratio and microbial stress indicators (the ratio of saturated to monounsaturated fatty acids, Sat:Mono) were significantly lower on the north-facing slopes than on the south-facing slopes. The resistance and resilience of microbial respiration were also lower on the north-facing slopes than on the south-facing slopes. Resistance and resilience were significantly related to bacterial biomass and microbial stress indicators, suggesting that the soil bacterial community on north-facing slopes, which is dominated by stress-intolerant bacteria, is more vulnerable to drying and rewetting than that on the south-facing slopes. These results provide insights into how the stability of soil functions can vary at a local scale, highlighting the importance of topography in predicting the consequences of environmental changes. • Slope aspects influence soil microbial community structure in a cool-temperate forest, with north-facing slopes dominated by bacteria and south-facing slopes dominated by fungi. • Slope aspects influence the resistance and resilience of soil microbial respiration to drying-rewetting. • The resistance and resilience of soil microbial respiration were significantly related to specific abiotic factors and indicators of soil microbial community structure.