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| Titel |
Divergence of above- and belowground C and N pool within predominant plant species along two precipitation gradients in North China |
| VerfasserIn |
X. H. Ye, X. Pan, W. K. Cornwell, S. Q. Gao, M. Dong, J. H. C. Cornelissen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 2 ; Nr. 12, no. 2 (2015-01-27), S.457-465 |
| Datensatznummer |
250117783
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| Publikation (Nr.) |
 copernicus.org/bg-12-457-2015.pdf |
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| Zusammenfassung |
| The coupling of carbon cycle and nitrogen cycle drives the food web structure
and biogeochemistry of an ecosystem. However, across precipitation
gradients, there may be a shift in C pool and N pool from above- to
belowground because of shifting plant stoichiometry and allocation. Based
on previous evidence, biomass allocation to roots should increase with
aridity, while leaf [N] should increase. If their effect sizes are equal,
they should cancel each other out, and the above- and belowground
proportions of the N would remain constant. Here, we present the first study
to explicitly compare above- and belowground pool sizes of N and C within
predominant plant species along precipitation gradients. Biomass and
nutrient concentrations of leaves, stems and roots of three predominant
species were measured along two major precipitation gradients in Inner
Mongolia, China. Along the two gradients, the effect sizes of the
biomass shifts were remarkably consistent among three predominant species.
However, the size of the shift in aboveground [N] was not, leading to a
species-specific pattern in above- and belowground pool size. In two
species (Stipa grandis and Artemisia ordosica) the effect sizes of biomass allocation and [N] were equal
and the proportion of N of above- and belowground did not change with
aridity, but in S. bungeana the increase in leaf [N] with aridity was much weaker than
the biomass shift, leading to a decrease in the proportion of N aboveground
at dry sites. We have found examples of consistent N pool sizes above- and
belowground and a shift to a greater proportion of belowground N in drier
sites depending on the species. We suggest that precipitation gradients do
potentially decouple the C and N pool, but the exact nature of the
decoupling depends on the dominant species' capacity for intraspecific
variation. |
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