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| Titel |
Disruption of metal ion homeostasis in soils is associated with nitrogen deposition-induced species loss in an Inner Mongolia steppe |
| VerfasserIn |
Q.-Y. Tian, N.-N. Liu, W.-M. Bai, L.-H. Li, W.-H. Zhang |
| 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. 11 ; Nr. 12, no. 11 (2015-06-09), S.3499-3512 |
| Datensatznummer |
250117974
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| Publikation (Nr.) |
 copernicus.org/bg-12-3499-2015.pdf |
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| Zusammenfassung |
| Enhanced deposition of atmospheric nitrogen (N) resulting from anthropogenic
activities has negative impacts on plant diversity in ecosystems. Several
mechanisms have been proposed to explain the species loss. Ion toxicity due
to N deposition-induced soil acidification has been suggested to be
responsible for species loss in acidic grasslands, while few studies have
evaluated the role of soil-mediated homeostasis of ions in species loss
under elevated N deposition in grasslands with neutral or alkaline soils. To
determine whether soil-mediated processes are involved in changes in
biodiversity induced by N deposition, the effects of 9-year N addition on
soil properties, aboveground biomass (AGB) and species richness were
investigated in an Inner Mongolia steppe. Low to moderate N addition rate
(2, 4, 8 g N m−2 yr−1) significantly enhanced AGB of graminoids,
while high N addition rate (≥ 16 g N m−2 yr−1) reduced AGB of
forbs, leading to an overall increase in AGB of the community under low to
moderate N addition rates. Forb richness was significantly reduced by N
addition at rates greater than 8 g N m−2 yr−1, while no effect of
N addition on graminoid richness was observed, resulting in decline in total
species richness. N addition reduced soil pH, depleted base cations
(Ca2+, Mg2+ and K+) and mobilized Mn2+, Fe3+,
Cu2+ and Al3+ ions in soils. Soil inorganic-N concentration was
negatively correlated with forb richness and biomass, explaining 23.59%
variation of forb biomass. The concentrations of base cations (Ca2+ and
Mg2+) and metal ions (Mn2+, Cu2+ and, Fe3+) showed
positively and negatively linear correlation with forb richness,
respectively. Changes in the metal ion concentrations accounted for
42.77% variation of forb richness, while reduction of base cations was
not associated with the reduction in forb richness. These results reveal
that patterns of plant biodiversity in the temperate steppe of Inner
Mongolia are primarily driven by increases in metal ion availability,
particularly enhanced release of soil Mn2+. |
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