The continent-scale variations in soil microbial respiration in forest
ecosystems: diverged pattern and mechanism
Abstract
Globally rising soil microbial respiration (Rm) is a key process
controlling the soil-to-atmosphere CO2 flux, yet its spatial variation
and underlying mechanism at different scales is still poorly understood.
A novel experiment based on the annual mean temperature of soil origin
sites along a 4,200 km north–south transect of China forests revealed a
hump-shaped relationship between Rm and latitude with a latitudinal
threshold of 32.5°N. Microbial variables were more important in shaping
Rm’ spatial variation at the continental scale than at the regional
scales, but soil physicochemical property had comparably unique
importance at different scales. Labile organic C was the most important
factor in regulating the Rm’s variation at the continent and in the
latitude > 32.5°N region, but fungi biomass was the most
important factor in the latitude < 32.5°N region. Overall, our
findings suggest different controlling factors of Rm’s variations on
either side of the latitudinal threshold.