Simulated NH 4 + -N Deposition Inhibits CH 4 Uptake and Promotes N 2 O Emission in the Meadow Steppe of Inner Mongolia, China

Normalized difference vegetation index (NDVI) is commonly used to indicate vegetation density and condition. NDVI was mostly correlated with climate factors. We analyzed changing trends of NDVI in different types of grassland in Inner Mongolia and the response of NDVI to climatic variation from 1982 to 2011. NDVI of meadow steppe increased significantly in spring while it decreased in other seasons. The annual mean NDVI in typical steppe and desert steppe increased significantly in the last 30a. However, in the greatest area of steppe desert, the NDVI had no significant change in summer, autumn, and the growing season. In meadow steppe, typical steppe, and desert steppe, the area showed a positive correlation of NDVI to temperature as highest in spring compared to other seasons, because warming in spring is beneficial to the plant growth. However, in the greatest area of steppe desert, the correlation of NDVI to temperature was not significant. The NDVI was positively correlated to precipitation in four types of grassland. In the steppe desert, the precipitation had no significant effect on the NDVI due to the poor vegetation cover in this region. The NDVI was not significantly correlated to the precipitation in autumn because of vegetation withering in the season and not need precipitation. Precipitation was a more important factor rather than temperature to NDVI in the region. The response of NDVI to temperature and precipitation in different seasons should be studied in more detail and the effect of other factors on NDVI should be considered in future research.

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Testing mechanisms of N-enrichment-induced species loss in a semiarid Inner Mongolia grassland: critical thresholds and implications for long-term ecosystem responses

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0352 ◽

2012 ◽

Vol 367 (1606) ◽

pp. 3125-3134 ◽

Cited By ~ 51

Author(s):

Zhichun Lan ◽

Yongfei Bai

Keyword(s):

Ecosystem Services ◽

Rare Species ◽

Inner Mongolia ◽

Global Environmental Change ◽

N Deposition ◽

Critical Threshold ◽

Species Loss ◽

N Addition ◽

Precipitation Regimes ◽

N Enrichment

The increase in nutrient availability as a consequence of elevated nitrogen (N) deposition is an important component of global environmental change. This is likely to substantially affect the functioning and provisioning of ecosystem services by drylands, where water and N are often limited. We tested mechanisms of chronic N-enrichment-induced plant species loss in a 10-year field experiment with six levels of N addition rate. Our findings on a semi-arid grassland in Inner Mongolia demonstrated that: (i) species richness (SR) declined by 16 per cent even at low levels of additional N (1.75 g N m –2 yr −1 ), and 50–70% species were excluded from plots which received high N input (10.5–28 g N m −2 yr −1 ); (ii) the responses of SR and above-ground biomass (AGB) to N were greater in wet years than dry years; (iii) N addition increased the inter-annual variations in AGB, reduced the drought resistance of production and hence diminished ecosystem stability; (iv) the critical threshold for chronic N-enrichment-induced reduction in SR differed between common and rare species, and increased over the time of the experiment owing to the loss of the more sensitive species. These results clearly indicate that both abundance and functional trait-based mechanisms operate simultaneously on N-induced species loss. The low initial abundance and low above-ground competitive ability may be attributable to the loss of rare species. However, shift from below-ground competition to above-ground competition and recruitment limitation are likely to be the key mechanisms for the loss of abundant species, with soil acidification being less important. Our results have important implications for understanding the impacts of N deposition and global climatic change (e.g. change in precipitation regimes) on biodiversity and ecosystem services of the Inner Mongolian grassland and beyond.

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Observation and modeling of plant biomass of meadow steppe in Tumugi, Xingan League, Inner Mongolia, China

Vegetatio ◽

10.1007/bf00044640 ◽

1996 ◽

Vol 127 (2) ◽

pp. 191-201 ◽

Cited By ~ 6

Author(s):

Xiangming Xiao ◽

Du Chen ◽

Yumei Peng ◽

Xianyi Cui ◽

Dennis S. Ojima

Keyword(s):

Inner Mongolia ◽

Plant Biomass ◽

Meadow Steppe

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Effect of grazing intensity on carbon and nitrogen in soil and vegetation in a meadow steppe in Inner Mongolia

Agriculture Ecosystems & Environment ◽

10.1016/j.agee.2007.11.009 ◽

2008 ◽

Vol 125 (1-4) ◽

pp. 21-32 ◽

Cited By ~ 139

Author(s):

Guodong Han ◽

Xiying Hao ◽

Mengli Zhao ◽

Mingjun Wang ◽

Ben H. Ellert ◽

...

Keyword(s):

Inner Mongolia ◽

Grazing Intensity ◽

Meadow Steppe ◽

Carbon And Nitrogen

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Effect of mowing on N2O and CH4 fluxes emissions from the meadow-steppe grasslands of Inner Mongolia

Frontiers of Earth Science ◽

10.1007/s11707-014-0486-z ◽

2015 ◽

Vol 9 (3) ◽

pp. 473-486 ◽

Cited By ~ 6

Author(s):

Zedong Lu ◽

Rui Du ◽

Pengrui Du ◽

Ziming Li ◽

Zongmin Liang ◽

...

Keyword(s):

Inner Mongolia ◽

Meadow Steppe

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Root tissue and shoot litter decomposition of dominant species Stipa baicalensis in Hulun Buir meadow steppe of Inner Mongolia, China

Chinese Journal of Plant Ecology ◽

10.3724/sp.j.1258.2011.01156 ◽

2011 ◽

Vol 35 (11) ◽

pp. 1156-1166

Author(s):

Cai-Hong ZHANG ◽

Lei-Ming ZHANG ◽

Xing-Ren LIU ◽

Xiao-Ping XIN ◽

Sheng-Gong LI

Keyword(s):

Litter Decomposition ◽

Inner Mongolia ◽

Dominant Species ◽

Root Tissue ◽

Meadow Steppe

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Disruption of metal ion homeostasis in soils is associated with nitrogen deposition-induced species loss in an Inner Mongolia steppe

Biogeosciences ◽

10.5194/bg-12-3499-2015 ◽

2015 ◽

Vol 12 (11) ◽

pp. 3499-3512 ◽

Cited By ~ 11

Author(s):

Q.-Y. Tian ◽

N.-N. Liu ◽

W.-M. Bai ◽

L.-H. Li ◽

W.-H. Zhang

Keyword(s):

Species Richness ◽

Inner Mongolia ◽

Metal Ion ◽

Ion Homeostasis ◽

Base Cations ◽

N Deposition ◽

Species Loss ◽

N Addition ◽

Metal Ion Homeostasis ◽

Addition Rate

Abstract. 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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