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Dynamics and multi‐annual fate of atmospherically deposited nitrogen in montane tropical forests
Author(s) -
Wang Ang,
Chen Dexiang,
Phillips Oliver L.,
Gundersen Per,
Zhou Xulun,
Gurmesa Geshere A.,
Li Shanlong,
Zhu Weixing,
Hobbie Erik A.,
Wang Xueyan,
Fang Yunting
Publication year - 2021
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.15526
Subject(s) - ecosystem , environmental science , forest ecology , temperate climate , terrestrial ecosystem , tropical and subtropical moist broadleaf forests , temperate forest , deposition (geology) , old growth forest , tropics , ecology , agronomy , agroforestry , subtropics , biology , paleontology , sediment
The effects of nitrogen (N) deposition on forests largely depend on its fate after entering the ecosystem. While several studies have addressed the forest fate of N deposition using 15 N tracers, the long‐term fate and redistribution of deposited N in tropical forests remains unknown. Here, we applied 15 N tracers to examine the fates of deposited ammonium ( NH 4 + ) and nitrate ( NO 3 ‐ ) separately over 3 years in a primary and a secondary tropical montane forest in southern China. Three months after 15 N tracer addition, over 60% of 15 N was retained in the forests studied. Total ecosystem retention did not change over the study period, but between 3 months and 3 years following deposition 15 N recovery in plants increased from 10% to 19% and 13% to 22% in the primary and secondary forests, respectively, while 15 N recovery in the organic soil declined from 16% to 2% and 9% to 2%. Mineral soil retained 50% and 35% of 15 N in the primary and secondary forests, with retention being stable over time. The total ecosystem retention of the two N forms did not differ significantly, but plants retained more15 NO 3 ‐than15 NH 4 +and the organic soil more15 NH 4 +than NO 3 ‐ . Mineral soil did not differ in15 NH 4 +and15 NO 3 ‐retention. Compared to temperate forests, proportionally more 15 N was distributed to mineral soil and plants in these tropical forests. Overall, our results suggest that atmospherically deposited NH 4 + and NO 3 ‐ is rapidly lost in the short term (months) but thereafter securely retained within the ecosystem, with retained N becoming redistributed to plants and mineral soil from the organic soil. This long‐term N retention may benefit tropical montane forest growth and enhance ecosystem carbon sequestration.