Effects of Canopy Damage and Litterfall Input on CO₂-Fixing Bacterial Communities

Abstract

Extreme weather events often cause canopy disturbance and litter deposition. To study the CO2-fixing bacterial response to forest damage, we simulated the canopy damage caused by extreme weather with four different treatments: control (CN), canopy trimming + removal of branches and leaves debris (TR), canopy trimming + retaining of branches and leaves debris (TD), and undamaged + transplantation of branches and leaves debris (UD). We used the cbbL gene, which encodes ribulose-1,5-biphosphate carboxylase/oxygenase (RubisCO), for Miseq sequencing to analyze the dynamics of community composition of soil CO2-fixing bacteria for five consecutive years after canopy damage. Double treatments of canopy damage and litterfall inputs (TD) facilitate forest restoration better than single treatments (TR or UD). Most soil CO2-fixing bacteria are facultative autotrophic bacteria, and Nitrosospira, Streptomyces, and Saccharomonospora are the main carbon-fixing microorganisms, which have significant differences during the restoration of damaged forest canopy. The forest ecosystem restoration after canopy damage lasted 4–5 years. Rainfall and pH showed a significant negative correlation with most soil CO2-fixing bacteria communities. This study provides a theoretical basis for improving the carbon sequestration capacity of forest soil CO2-fixing bacteria after extreme weather and also provides guidance for forest ecosystem management.

Keywords

• extreme weather events
• canopy openness
• litterfall decomposition
• CO₂-fixing bacteria
• <i>cbbL</i> gene