Climate change impacts on mycorrhizae amplify nitrogen limitation on
global plant growth
Abstract
Most tree species predominantly associate with a single type of
mycorrhizal fungi. Because of the principle differences in mycorrhizal
associations, they can differentially affect plant nutrient acquisition
and biogeochemical cycling. Here, we use the updated carbon-nitrogen
economics within the Community Land Model version 5 (CLM5) to evaluate
the impact of mycorrhizal association on the global nitrogen and carbon
cycles. Different spatial distributions of plant mycorrhizal
associations lead to clear differences in present day Net Primary
Productivity by up to 345 ± 21 TgCyr-1, owing to the
impacts of different symbioses on carbon costs of nitrogen acquisition
(4.3% more costly than those originally proposed on average). Simulated
global NPP increased throughout the 21st century by
20%, while the carbon costs of nitrogen acquisition have increased at a
faster rate by 50%. This suggests that nutrient acquisition will
increasingly demand a higher portion of assimilated carbon to support
the same productivity.