A meta-analysis of understory plant removal impacts on soil properties in forest ecosystems

Abstract

Understory plants have an important role in regulating various functions and processes in forest ecosystems. However, the overall consequences of understory plant losses on soil properties remain unclear. Here, we used a meta-analysis to determine overall trends in soil organic carbon, total nitrogen and microorganism following understory removal experiments in forest ecosystems of China. Sites with removed understories exhibited significant increases in soil temperature and decreases in soil organic carbon, total nitrogen, soil water content, pH, and microbial biomass. Fungi responded more quickly to plant removal than bacteria. Negative effects were increased with treatment duration and were stronger in broad-leaved forests than in coniferous forests. The responses of soil water, nutrient content, and microbial community composition to understory plant removal diminished as mean annual temperature and precipitation decreased. Our study showed that the effects of understory plant removal on soil properties varied among experimental durations, ecosystem types, and environmental factors (i.e., mean annual temperature, mean annual precipitation, and latitude). These results indicate that understory plants help in sustaining soil organic carbon, total nitrogen, and microbial activities in forest ecosystems. Our findings suggest that understory plants should be maintained to support the health of forest ecosystems.