This study investigated the relative importance of ecosystem type and soil age on soil carbon fractions across 16 global chronosequences. The results showed that ecosystem type, specifically productivity, is a stronger driver of carbon fraction proportions than soil age (spanning centuries to millennia). Highly productive tropical and temperate forests had more unprotected carbon, vulnerable to productivity decline and warming. Conversely, less productive ecosystems had mineral-protected carbon, less responsive to warming. The findings highlight the importance of preserving ecosystem productivity for soil carbon protection.

César Plaza, Pablo García-Palacios, Asmeret Asefaw Berhe, Jesús Barquero, Felipe Bastida, G. Kenny Png, Ana Rey, Richard D. Bardgett, Manuel Delgado-Baquerizo