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Gewählte Publikation:

Tang, SB; Liu, JF; Gilliam, FS; Hietz, P; Wang, ZH; Lu, XK; Zeng, FY; Wen, DZ; Hou, EQ; Lai, Y; Fang, YT; Tu, Y; Xi, D; Huang, ZQ; Zhang, DX; Wang, R; Kuang, YW.
(2022): Drivers of foliar N-15 trends in southern China over the last century
GLOBAL CHANGE BIOL. 2022; 28(18): 5441-5452. FullText FullText_BOKU

Abstract:
Foliar stable nitrogen (N) isotopes (delta N-15) generally reflect N availability to plants and have been used to infer about changes thereof. However, previous studies of temporal trends in foliar delta N-15 have ignored the influence of confounding factors, leading to uncertainties on its indication to N availability. In this study, we measured foliar delta N-15 of 1811 herbarium specimens from 12 plant species collected in southern China forests from 1920 to 2010. We explored how changes in atmospheric CO2, N deposition and global warming have affected foliar delta N-15 and N concentrations ([N]) and identified whether N availability decreased in southern China. Across all species, foliar delta N-15 significantly decreased by 0.82 parts per thousand over the study period. However, foliar [N] did not decrease significantly, implying N homeostasis in forest trees in the region. The spatiotemporal patterns of foliar delta N-15 were explained by mean annual temperature (MAT), atmospheric CO2 (PCO2$$ {\mathrm{P}}_{{\mathrm{CO}}_2} $$), atmospheric N deposition, and foliar [N]. The spatiotemporal trends of foliar [N] were explained by MAT, temperature seasonality, PCO2$$ {\mathrm{P}}_{{\mathrm{CO}}_2} $$, and N deposition. N deposition within the rates from 5.3 to 12.6 kg N ha(-1) year(-1) substantially contributed to the temporal decline in foliar delta N-15. The decline in foliar delta N-15 was not accompanied by changes in foliar [N] and therefore does not necessarily reflect a decline in N availability. This is important to understand changes in N availability, which is essential to validate and parameterize biogeochemical cycles of N.
Autor*innen der BOKU Wien:
Hietz Peter
BOKU Gendermonitor:


Find related publications in this database (Keywords)
atmospheric CO(2)global change
foliar nitrogen concentrations
foliar nitrogen isotopes
nitrogen availability
nitrogen deposition


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