scholarly journals Precipitation and aridity index regulating spatial patterns of vegetation production and species diversity based on alpine grassland transect, Tibetan Plateau

2016 ◽  
Author(s):  
Jian Sun
Keyword(s):  
Tibetan Plateau ◽  
Primary Production ◽  
Alpine Meadow ◽  
Net Primary Production ◽  
Aridity Index ◽  
Alpine Grassland ◽  
The Tibetan Plateau ◽  
Aboveground Net Primary Production ◽  
Alpine Steppe ◽  
Unimodal Pattern

Although the relationship between the aboveground net primary production (ANPP) and speciesdiversity (SR) have been widely reported, there is considerable disagreement about the fitting patterns of SR–ANPP, which has been variously described as ‘positive’, ‘negative’, ‘unimodal’, ‘U-shaped’ and so on. Not surprisingly, the effect-factors including precipitation, aridity index and geographic conditions (e.g.,altitude, longitude and latitude) on ANPP and SR continue to interest researchers, especially the effects at high altitude regions. We investigated ANPP and SR from 113 sampled sites (399 plots) across alpine meadow and steppe in the Tibetan Plateau, which included Tibet, Qinghai and Sichuan province. The effects of various environmental factors (precipitation, temperature, aridity index, altitude, longitude,latitude and vegetation type on SR and ANPP) were explored. The results indicate that a unimodal pattern was confirmed between ANPP and SR in alpine steppe (R 2 =0.45, P <0.0001), alpine meadow ( R 2 =0.4, P <0.0001), and all samples across alpine grassland ( R 2 =0.52, P <0.0001). For the aboveground net primary production, the appropriate precipitation and aridity is 600mm and 42, respectively. Under thesame moisture conditions, the maximum value of diversity is 0.75. Longitude ( R 2 =0.69, P <0.0001) and altitude ( R 2 =0.48, P <0.0001) have positive and negative effects on aboveground net primary production, and a similar relationship exists with diversity ( R 2 =0.44, P <0.0001 and R 2 =0.3, P <0.0001).The same patterns of diversity and production responding to precipitation and the aridity index were evident in alpine steppe and meadow, and a unimodal pattern was confirmed between ANPP and SR in both locations.

scholarly journals Precipitation and aridity index regulating spatial patterns of vegetation production and species diversity based on alpine grassland transect, Tibetan Plateau

2016 ◽  
Author(s):  
Jian Sun
Keyword(s):  
Tibetan Plateau ◽  
Primary Production ◽  
Alpine Meadow ◽  
Net Primary Production ◽  
Aridity Index ◽  
Alpine Grassland ◽  
The Tibetan Plateau ◽  
Aboveground Net Primary Production ◽  
Alpine Steppe ◽  
Unimodal Pattern

Although the relationship between the aboveground net primary production (ANPP) and speciesdiversity (SR) have been widely reported, there is considerable disagreement about the fitting patterns of SR–ANPP, which has been variously described as ‘positive’, ‘negative’, ‘unimodal’, ‘U-shaped’ and so on. Not surprisingly, the effect-factors including precipitation, aridity index and geographic conditions (e.g.,altitude, longitude and latitude) on ANPP and SR continue to interest researchers, especially the effects at high altitude regions. We investigated ANPP and SR from 113 sampled sites (399 plots) across alpine meadow and steppe in the Tibetan Plateau, which included Tibet, Qinghai and Sichuan province. The effects of various environmental factors (precipitation, temperature, aridity index, altitude, longitude,latitude and vegetation type on SR and ANPP) were explored. The results indicate that a unimodal pattern was confirmed between ANPP and SR in alpine steppe (R 2 =0.45, P <0.0001), alpine meadow ( R 2 =0.4, P <0.0001), and all samples across alpine grassland ( R 2 =0.52, P <0.0001). For the aboveground net primary production, the appropriate precipitation and aridity is 600mm and 42, respectively. Under thesame moisture conditions, the maximum value of diversity is 0.75. Longitude ( R 2 =0.69, P <0.0001) and altitude ( R 2 =0.48, P <0.0001) have positive and negative effects on aboveground net primary production, and a similar relationship exists with diversity ( R 2 =0.44, P <0.0001 and R 2 =0.3, P <0.0001).The same patterns of diversity and production responding to precipitation and the aridity index were evident in alpine steppe and meadow, and a unimodal pattern was confirmed between ANPP and SR in both locations.

scholarly journals Meta-analysis of relationships between environmental factors and aboveground biomass in the alpine grassland on the Tibetan Plateau

2013 ◽  
Vol 10 (3) ◽  
pp. 1707-1715 ◽  
Author(s):  
J. Sun ◽  
G. W. Cheng ◽  
W. P. Li
Keyword(s):  
Soil Moisture ◽  
Tibetan Plateau ◽  
Environmental Factors ◽  
Aboveground Biomass ◽  
Alpine Meadow ◽  
Meta Analysis ◽  
Alpine Grassland ◽  
Mean Annual Precipitation ◽  
The Tibetan Plateau ◽  
Alpine Steppe

Abstract. The Tibetan Plateau, known as the "world's third pole" for its extremely harsh and fragile ecological environment, has attracted great attention because of its sensitivity to global changes. Alpine grassland on the Tibetan Plateau has an important function in the global carbon cycle. Many studies have examined the effects of various environmental factors on biomass distribution. In this study, the relationships between the habitat parameters and the aboveground biomass (AGB) abundance on the Tibetan Plateau were examined through a meta-analysis of 110 field sites across the widely distributed alpine steppe and meadow. The obtained data were then analysed using the classification and regression tree model and the generalized additive model. The results showed that the AGB abundance in alpine steppe was positively correlated with six environmental factors, namely, soil organic carbon density of the top soil layer from 0 cm to 30 cm (SOC30 cm), longitude, mean annual precipitation (MAP), latitude, clay, and soil moisture. For the alpine meadow, five main factors were detected, namely, altitude, soil moisture, nitrogen, MAP, and mean annual temperature. The increased AGB abundance in the alpine steppe was associated with the increased SOC30 cm, MAP, and latitude, and the increased longitude resulted in decreased AGB abundance. For the alpine meadow, altitude and soil moisture showed strongly negative effects on AGB abundance, and soil nitrogen content was positively related to the AGB distribution across all examined sites. Our results suggest the combined effects of meteorological, topographic, and soil factors on the spatial patterns of AGB on the Tibetan Plateau.

Water and CO2 fluxes over semiarid alpine steppe and humid alpine meadow ecosystems on the Tibetan Plateau

2016 ◽  
Vol 131 (1-2) ◽  
pp. 547-556 ◽  
Author(s):  
Lei Wang ◽  
Huizhi Liu ◽  
Yaping Shao ◽  
Yang Liu ◽  
Jihua Sun
Keyword(s):  
Tibetan Plateau ◽  
Alpine Meadow ◽  
The Tibetan Plateau ◽  
Co2 Fluxes ◽  
Alpine Steppe

scholarly journals Field evidence for earlier leaf-out dates in alpine grassland on the eastern Tibetan Plateau from 1990 to 2006

2014 ◽  
Vol 10 (8) ◽  
pp. 20140291 ◽  
Author(s):  
H. K. Zhou ◽  
B. Q. Yao ◽  
W. X. Xu ◽  
X. Ye ◽  
J. J. Fu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Alpine Meadow ◽  
Grassland Management ◽  
The Tibetan Plateau ◽  
Spring Phenology ◽  
Ecosystem Responses ◽  
Vegetation Communities ◽  
Alpine Steppe ◽  
Field Evidence

Worldwide, many plant species are experiencing an earlier onset of spring phenophases due to climate warming. Rapid recent temperature increases on the Tibetan Plateau (TP) have triggered changes in the spring phenology of the local vegetation. However, remote sensing studies of the land surface phenology have reached conflicting interpretations about green-up patterns observed on the TP since the mid-1990s. We investigated this issue using field phenological observations from 1990 to 2006, for 11 dominant plants on the TP at the levels of species, families (Gramineae—grasses and Cyperaceae—sedges) and vegetation communities (alpine meadow and alpine steppe). We found a significant trend of earlier leaf-out dates for one species ( Koeleria cristata ). The leaf-out dates of both Gramineae and Cyperaceae had advanced (the latter significantly, starting an average of 9 days later per year than the former), but the correlation between them was significant. The leaf-out dates of both vegetation communities also advanced, but the pattern was only significant in the alpine meadow. This study provides the first field evidence of advancement in spring leaf phenology on the TP and suggests that the phenology of the alpine steppe can differ from that of the alpine meadow. These findings will be useful for understanding ecosystem responses to climate change and for grassland management on the TP.

Comparative analysis of land surface parameters on three typical underlying surfaces over the Tibetan Plateau

2020 ◽  
Author(s):  
Zhangwei Ding ◽  
Yaoming Ma ◽  
Xuelong Chen
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Alpine Meadow ◽  
Bare Soil ◽  
Alpine Grassland ◽  
The Tibetan Plateau ◽  
Transfer Coefficients ◽  
Surface Parameters ◽  
Yearly Average ◽  
Land Surface Parameters

&lt;p&gt;To improve land surface parameterizations of radiation and energy balance, eddy covariance measurements were performed on three typical land covers types over the Tibetan Plateau , including bare soil, naturally sparse alpine meadow and dense alpine grassland from 2007 to 2012. We investigated how land surface parameters changed with surface properties and vegetation canopy growth and analyzed the characteristics of diurnal and seasonal variations of aerodynamic parameters. Results show that the annual mean surface albedo and surface roughness lengths for momentum were 0.27 and 2.29 cm, 0.241 and 1.39 cm and 0.19 and 6.52 cm over bare soil, naturally sparse alpine meadow and dense alpine grassland areas, respectively. The yearly average turbulence transfer coefficients for momentum and sensible heat under neutral condition were 4.12&amp;#215;10&lt;sup&gt;-3&lt;/sup&gt; and 2.29&amp;#215;10&lt;sup&gt;-3&lt;/sup&gt;, 4.11&amp;#215;10&lt;sup&gt;-3&lt;/sup&gt; and 2.33&amp;#215;10&lt;sup&gt;-3&lt;/sup&gt; and 6.67&amp;#215;10&lt;sup&gt;-3&lt;/sup&gt; and 4.14&amp;#215;10&lt;sup&gt;-3&lt;/sup&gt;, respectively. The median values of &amp;#954;B&lt;sup&gt;-1&lt;/sup&gt; averaged over multiple years are 6.65, 5.89 and 4.88, respectively.&lt;/p&gt;

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