Extreme drought alters the vertical distribution but not the total
amount of grassland root biomass
Abstract
Extreme drought impacts ecosystem function and processes dramatically.
However, a comprehensive understanding of how extreme drought affects
root biomass at regional scales remains elusive. Here, we investigated
the effects across six grasslands with extreme drought treatment
replicated across a precipitation gradient in Inner Mongolia, China. We
found the root biomass and belowground net primary productivity (BNPP)
were significantly positively correlated with precipitation at the
reginal scale. Extreme drought decreased the slope of this correlation
in 0-10 cm and increased in 10-20 cm. Root biomass and BNPP increased by
extreme drought in the four relatively arid sites and decreased in the
two relatively mesic sites in 0-10 cm, and the reverse pattern showed in
10-20 cm. These shifts were driven by the response of soil moisture. Our
findings suggest that including vertical responses of belowground
primary productivity to extreme drought should improve models
predictions of plant roots to future climate change.