scholarly journals Grazing primarily drives the relative abundance change of C4 plants in the typical steppe grasslands across households at a regional scale

2014 ◽  
Vol 36 (6) ◽  
pp. 565 ◽  
Author(s):  
Qing Zhang ◽  
Yong Ding ◽  
Wenjing Ma ◽  
Sarula Kang ◽  
Xin Li ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Inner Mongolia ◽  
Regional Scale ◽  
Grazing Intensity ◽  
C4 Plants ◽  
C3 Plants ◽  
Mean Annual Temperature ◽  
Typical Steppe ◽  
Primary Driver ◽  
Grassland Communities

Increases in temperature and grazing intensity are believed to promote the relative abundance of C4 plants in grassland communities in Inner Mongolia. However, there is a lack of understanding as to which factor is the primary driver at the household scale. The relative abundance of C4 plants in grassland communities within 32 households was monitored over a 5-year period (2008–12) in the typical steppe region of Inner Mongolia. The relationships between the mean annual temperature, grazing intensity and their combinations on the patterns of the relative abundance of C4 plants across the land managed by these households were analysed. The results showed that (1) the herbage mass of the typical steppe grassland was mainly composed of C3 plants (87%); (2) the C4 plants were more sensitive to, and can be used as indicators of, environmental changes. These C4 species included Cleistogenes squarrosa (Trin.) Keng, Chenopodium glaucum Linn. and Salsola collina Pall.; (3) both increasing temperature and grazing intensity promoted the relative abundance of C4 plants. Grazing intensity was the primary driver of the change in relative abundance of C4 plants in this region. Not only did grazing change the micro-environment of the grasslands, but also the C3 species were preferentially grazed by the livestock. Comparison of the results with previous studies on the temporal variation in the abundance of C4 plants suggests that the relative importance of grazing and climatic factors depends on the spatial scales of the studies, with climate being of greater importance at the regional rather than the household scale.

scholarly journals Large regional-scale variation in C3/C4 distribution pattern of Inner Mongolia steppe is revealed by grazer wool carbon isotope composition

2009 ◽  
Vol 6 (5) ◽  
pp. 795-805 ◽  
Author(s):  
K. Auerswald ◽  
M. H. O. M. Wittmer ◽  
T. T. Männel ◽  
Y. F. Bai ◽  
R. Schäufele ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Inner Mongolia ◽  
Isotope Composition ◽  
Regional Scale ◽  
C4 Plants ◽  
Entire Area ◽  
Community Biomass ◽  
Farm Scale ◽  
Sheep Wool ◽  
Scale Variation

Abstract. This work explored the spatial variation of C3/C4 distribution in the Inner Mongolia, P. R. China, steppe by geostatistical analysis of carbon isotope data of vegetation and sheep wool. Standing community biomass (n=118) and sheep wool (n=146) were sampled in a ~0.2 Mio km2 area. Samples from ten consecutive years (1998–2007) were obtained. Community biomass samples represented the carbon isotopic composition of standing vegetation on about 1000 m2 ("community-scale"), whereas the spatio-temporal scale of wool reflected the isotope composition of the entire area grazed by the herd during a 1-yr period (~5–10 km2, "farm-scale"). Pair wise sampling of wool and vegetation revealed a 13C-enrichment of 2.7±0.7‰ (95% confidence interval) in wool relative to vegetation, but this shift exhibited no apparent relationships with environmental parameters or stocking rate. The proportion of C4 plants in above-ground biomass (PC4, %) was estimated with a two-member mixing model of 13C discrimination by C3 and C4 vegetation (13Δ3 and 13Δ4, respectively), in accounting for the effects of changing 13C in atmospheric CO2 on sample isotope composition, and of altitude and aridity on 13Δ3. PC4 averaged 19%, but the variation was enormous: full-scale (0% to 100%) at community-scale, and 0% to 85% at farm-scale. The farm-scale variation of PC4 exhibited a clear regional pattern over a range of ~250 km. Importantly PC4 was significantly higher above the 22°C isotherm of the warmest month, which was obtained from annual high-resolution maps and averaged over the different sampling years. This is consistent with predictions from C3/C4 crossover temperature of quantum yield or light use efficiency in C3 and C4 plants. Still, temperature gradients accounted for only 10% of the farm-scale variation of PC4, indicating that additional factors control PC4 on this scale.

scholarly journals Effects of Grazing Intensity and Environmental Factors on Species Composition and Diversity in Typical Steppe of Inner Mongolia, China

PLoS ONE ◽  
2012 ◽  
Vol 7 (12) ◽  
pp. e52180 ◽  
Author(s):  
Haiyan Ren ◽  
Philipp Schönbach ◽  
Hongwei Wan ◽  
Martin Gierus ◽  
Friedhelm Taube
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Inner Mongolia ◽  
Grazing Intensity ◽  
Typical Steppe

scholarly journals Large regional-scale variation in C3/C4 distribution pattern of Inner Mongolia steppe is revealed by grazer wool carbon isotope composition

2009 ◽  
Vol 6 (1) ◽  
pp. 545-574 ◽  
Author(s):  
K. Auerswald ◽  
M. H. O. M. Wittmer ◽  
T. T. Männel ◽  
Y. F. Bai ◽  
R. Schäufele ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Inner Mongolia ◽  
Isotope Composition ◽  
Regional Scale ◽  
C4 Plants ◽  
Entire Area ◽  
Community Biomass ◽  
Farm Scale ◽  
Sheep Wool ◽  
Scale Variation

Abstract. This work explored the spatial variation of C3/C4 distribution in the Inner Mongolia, China, steppe by geostatistical analysis of carbon isotope data of vegetation and sheep wool. Standing community biomass (n=118) and sheep wool (n=146) were sampled in a ~0.2 Mio km2 area. Samples from ten consecutive years (1998–2007) were obtained. Community biomass samples represented the carbon isotopic composition of standing vegetation on about 1000 m2 ("community-scale"), whereas the spatio-temporal scale of wool reflected the isotope composition of the entire area grazed by the herd during a 1-yr period (~5–10 km2, "farm-scale"). Pair wise sampling of wool and vegetation revealed a 13C-enrichment of 2.7‰ in wool relative to vegetation, but this shift exhibited no apparent relationships with environmental parameters or stocking rate. The proportion of C4 plants in above-ground biomass (PC4, %) was estimated with a two-member mixing model of C3 and C4 13C discrimination (13Δ3 and 13Δ4, respectively), in accounting for the effects of changing 13C in atmospheric CO2 on sample isotope composition, and of altitude and aridity on 13Δ3. PC4 averaged 19%, but the variation was enormous: full-scale (0% to 100%) at community-scale, and 0% to 85% at farm-scale. The farm-scale variation of PC4 exhibited a clear regional pattern over a range of ~250 km. Importantly PC4 was significantly higher above and lower below the 22°C isotherm of the warmest month, which was averaged from high-resolution maps of the sample years. This is consistent with predictions from C3/C4 crossover temperature of quantum yield in C3 and C4 plants. Still, temperature gradients accounted for only 10% of the farm-scale variation of PC4, indicating that additional factors control PC4 on this scale.

scholarly journals Different responses of plant species to deferment of sheep grazing in a desert steppe of Inner Mongolia, China

2014 ◽  
Vol 36 (6) ◽  
pp. 583 ◽  
Author(s):  
Zhen Wang ◽  
Xiangyang Hou ◽  
Michael P. Schellenberg ◽  
Yan Qin ◽  
Xiangjun Yun ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Inner Mongolia ◽  
Growing Season ◽  
C4 Plants ◽  
Annual Precipitation ◽  
C3 Plants ◽  
Desert Steppe ◽  
Sheep Grazing ◽  
Steppe Vegetation

This paper reports the effects of different deferments of sheep grazing on plant variables of desert steppe vegetation in Inner Mongolia during 2010–2012. The study was initiated in May 2010 and comprised five treatments: no grazing (UG), grazing throughout the growing season (G) and grazing deferment for 40, 50 and 60 days (40UG, 50UG and 60UG) from the start of the growing season in a completely randomised block design replicated three times. The plant species were classified into two functional groups (C3 and C4 species) and the relationships among species composition, biomass and annual precipitation were examined in different deferments of sheep grazing. Treatment G significantly decreased the biomass of several species compared with some of the deferred treatments and treatment UG, because of differences in grazing preferences, and, consequently, decreased the aboveground net primary productivity (ANPP). Grazing deferment for 40, 50 and 60 days significantly increased C3-species richness and biomass compared with treatment UG, whereas grazing sheep’s preferences for C4 plants at some growth stages compared with C3 plants, resulted in lower species richness and biomass of C4 plants in treatments G, 40UG and 50UG in a dry year. Similarly, different species responses to treatment 60UG resulted in an increase in ANPP in a year with more precipitation during the growing season. The annual precipitation patterns strongly affected the temporal changes in biomass as well as the responses to grazing, indicating that the plant responses in the desert steppe were co-limited by grazing and precipitation. These findings provide important insights into the management and conservation of desert steppe vegetation in Inner Mongolia.

scholarly journals Grazing Intensity on Vegetation Dynamics of a Typical Steppe in Northeast Inner Mongolia

2009 ◽  
Vol 62 (4) ◽  
pp. 328-336 ◽  
Author(s):  
Yan Liang ◽  
Guodong Han ◽  
He Zhou ◽  
Mengli Zhao ◽  
Hennie A. Snyman ◽  
...  
Keyword(s):  
Vegetation Dynamics ◽  
Inner Mongolia ◽  
Grazing Intensity ◽  
Typical Steppe

scholarly journals Does EO NDVI seasonal metrics capture variations in species composition and biomass due to grazing in semi-arid grassland savannas?

2015 ◽  
Vol 12 (14) ◽  
pp. 4407-4419 ◽  
Author(s):  
J. L. Olsen ◽  
S. Miehe ◽  
P. Ceccato ◽  
R. Fensholt
Keyword(s):  
Time Series ◽  
Species Composition ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Regional Scale ◽  
Grazing Intensity ◽  
Test Site ◽  
Grazing Pressure ◽  
Modis Ndvi ◽  
Coarse Resolution

Abstract. Most regional scale studies of vegetation in the Sahel have been based on Earth observation (EO) imagery due to the limited number of sites providing continuous and long term in situ meteorological and vegetation measurements. From a long time series of coarse resolution normalized difference vegetation index (NDVI) data a greening of the Sahel since the 1980s has been identified. However, it is poorly understood how commonly applied remote sensing techniques reflect the influence of extensive grazing (and changes in grazing pressure) on natural rangeland vegetation. This paper analyses the time series of Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI metrics by comparing it with data from the Widou Thiengoly test site in northern Senegal. Field data include grazing intensity, end of season standing biomass (ESSB) and species composition from sizeable areas suitable for comparison with moderate – coarse resolution satellite imagery. It is shown that sampling plots excluded from grazing have a different species composition characterized by a longer growth cycle as compared to plots under controlled grazing or communal grazing. Also substantially higher ESSB is observed for grazing exclosures as compared to grazed areas, substantially exceeding the amount of biomass expected to be ingested by livestock for this area. The seasonal integrated NDVI (NDVI small integral; capturing only the signal inherent to the growing season recurrent vegetation), derived using absolute thresholds to estimate start and end of growing seasons, is identified as the metric most strongly related to ESSB for all grazing regimes. However plot-pixel comparisons demonstrate how the NDVI/ESSB relationship changes due to grazing-induced variation in annual plant species composition and the NDVI values for grazed plots are only slightly lower than the values observed for the ungrazed plots. Hence, average ESSB in ungrazed plots since 2000 was 0.93 t ha−1, compared to 0.51 t ha−1 for plots subjected to controlled grazing and 0.49 t ha−1 for communally grazed plots, but the average integrated NDVI values for the same period were 1.56, 1.49, and 1.45 for ungrazed, controlled and communal, respectively, i.e. a much smaller difference. This indicates that a grazing-induced development towards less ESSB and shorter-cycled annual plants with reduced ability to turn additional water in wet years into biomass is not adequately captured by seasonal NDVI metrics.

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