Relationship Between Vegetation Restoration and Soil Microbial Characteristics in Degraded Karst Regions： A Case Study

The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade. In an attempt to preferably interpret the soil microbiological characteristic variation associated with vegetation restoration and further to explore the role of soil microbiology in vegetation restoration mechanism of degraded karst regions, we measured microbial biomass C and basal respiration in soils during vegetation restoration in Zhenfeng County of southwestern Guizhou Province, China. The community level physiological profiles （CLPP） of the soil microbial community to were estimated determine if vegetation changes were accompanied by changes in functioning of soil microbial communities. The results showed that soil microbial biomass C and microbial quotient （microbial biomass C/organic C） tended to increase with vegetation restoration, being in the order arboreal community stage 〉 shrubby community stage 〉 herbaceous community stage 〉 bare land stage. Similar trend was found in the change of basal respiration （BR）. The metabolic quotient （the ratio of basal respiration to microbial biomass, qCO2） decreased with vegetation restoration, and remained at a constantly low level in the arboreal community stage. Analyses of the CLPP data indicated that vegetation restoration tended to result in higher average well color development, substrate richness, and functional diversity. Average utilization of specific substrate guilds was highest in the arboreal community stage. Principle component analysis of the CLPP data further indicated that the arboreal community stage was distinctly different from the other three stages. In conclusion, vegetation restoration improved soil microbial biomass C, respiration, and utilization of carbon sources, and decreased qCO2, thus creating better soil conditions, which in turn could promote the restoration of vegetation on degraded karst regions.