scholarly journals Plant diversity is closely related to the density of zokor mounds in three alpine rangelands on the Tibetan Plateau

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6921 ◽  
Author(s):  
Yujie Niu ◽  
Jianwei Zhou ◽  
Siwei Yang ◽  
Bin Chu ◽  
Huimin Zhu ◽  
...  
Keyword(s):  
Species Richness ◽  
Soil Moisture ◽  
Tibetan Plateau ◽  
Plant Diversity ◽  
Alpine Meadow ◽  
Living Environment ◽  
The Tibetan Plateau ◽  
Alpine Steppe ◽  
Alpine Shrub ◽  
Plateau Zokor

Background Plateau zokor (Myospalax baileyi) is a subterranean rodent endemic to the Tibetan Plateau. This species has been generally viewed as a pest in China due to the competition for food with livestock and also causing soil erosion. As a result, plateau zokor has been the target of widespread poisoning or trapping campaigns designed to control or eliminate it since 1970s. But there is little research on the effect of plateau zokor on plant diversity in alpine rangelands. Therefore, objectively evaluating the positive effects of the plateau zokors disturbance on their living environment and plant communities is of great significance to understand the function of plateau zokor in alpine ecosystem. Methods Here, we selected three rangelands (alpine meadow, alpine steppe and alpine shrub meadow) in which plateau zokors are typically distributed on the Tibetan Plateau, and five zokor mound density gradients were selected in each rangeland type to study the effects of the mounds on soil moisture and temperature related to plant species diversity. Results The results showed that, with the mound density increasing, the soil temperature decreased significantly in all three rangeland types, and the soil moisture significantly increased in all three rangeland types. In the alpine meadow, both the plant diversity and cumulative species richness increased significantly with increasing mound density. The increase in broad-leaved forbs is the main reason for the increase of plant diversity in the alpine meadow disturbed by zokor mounds. In the alpine steppe, the plant diversity decreased significantly with increasing mound density, while the cumulative species richness initially decreased and then increased. In the alpine shrub meadow, the plant diversity first increased and then decreased with increasing mound density as did the cumulative species richness. In conclusion, plateau zokor mounds dominated the distribution of soil moisture and temperature and significantly affected plant diversity in these three rangelands on Tibetan Plateau; the results further deepen our understanding toward a co-evolved process.

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.

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.

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.

Effects of grazing and climate warming on plant diversity, productivity and living state in the alpine rangelands and cultivated grasslands of the Qinghai-Tibetan Plateau

2015 ◽  
Vol 37 (1) ◽  
pp. 57 ◽  
Author(s):  
Yong Zhang ◽  
Qingzhu Gao ◽  
Shikui Dong ◽  
Shiliang Liu ◽  
Xuexia Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Plant Diversity ◽  
Climate Warming ◽  
Alpine Meadow ◽  
Vegetation Type ◽  
Vegetation Height ◽  
Rangeland Degradation ◽  
Alpine Steppe ◽  
Forage Species ◽  
Living State

Overgrazing and climate warming may be important drivers of alpine rangeland degradation in the Qinghai-Tibetan Plateau (QTP). In this study, the effects of grazing and experimental warming on the vegetation of cultivated grasslands, alpine steppe and alpine meadows on the QTP were investigated. The three treatments were a control, a warming treatment and a grazing treatment and were replicated three times on each vegetation type. The warming treatment was applied using fibreglass open-top chambers and the grazing treatment was continuous grazing by yaks at a moderately high stocking rate. Both grazing and warming negatively affected vegetation cover. Grazing reduced vegetation height while warming increased vegetation height. Grazing increased but warming reduced plant diversity. Grazing decreased and warming increased the aboveground plant biomass. Grazing increased the preferred forage species in native rangelands (alpine steppe and alpine meadow), while warming increased the preferred forage species in the cultivated grassland. Grazing reduced the vegetation living state (VLS) of all three alpine grasslands by nearly 70%, while warming reduced the VLS of the cultivated grassland and the alpine steppe by 32% and 56%, respectively, and promoted the VLS of the alpine meadow by 20.5%. It was concluded that overgrazing was the main driver of change to the alpine grassland vegetation on the QTP. The findings suggest that grazing regimes should be adapted in order for them to be sustainable in a warmer future.

scholarly journals Warming Changed Soil Respiration Dynamics of Alpine Meadow Ecosystem on the Tibetan Plateau

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Junfeng Wang
Keyword(s):  
Global Warming ◽  
Soil Moisture ◽  
Tibetan Plateau ◽  
Soil Respiration ◽  
Co2 Emission ◽  
Alpine Meadow ◽  
The Tibetan Plateau ◽  
Soil Co2 ◽  
Q10 Value ◽  
Soil Co2 Emission

Alpine meadow system underlain by permafrost on the Tibetan Plateau contains vast soil organic carbon and is sensitive to global warming. However, the dynamics of annual soil respiration (Rs) under long-term warming and the determined factors are still not very clear. Using open-top chambers (OTC), we assessed the effects of two-year experimental warming on the soil CO2 emission and the Q10 value (temperature sensitivity coefficient) under different warming magnitudes. Our study showed that the soil CO2 efflux rate in the warmed plots were 1.22 and 2.32 times higher compared to that of controlled plots. However, the Q10 value decreased by 45.06% and 50.34% respectively as the warming magnitude increased. These results suggested that soil moisture decreasing under global warming would enhance soil CO2 emission and lower the temperature sensitivity of soil respiration rate of the alpine meadow ecosystem in the permafrost region on the Tibetan Plateau. Thus, it is necessary to take into account the combined effect of ground surface warming and soil moisture decrease on the Rs in order to comprehensively evaluate the carbon emissions of the alpine meadow ecosystem, especially in short and medium terms.

scholarly journals The critical factors that affected the distribution of aboveground biomass in the alpine steppe and meadow, Tibetan Plateau

2012 ◽  
Vol 9 (10) ◽  
pp. 14559-14588
Author(s):  
J. Sun ◽  
G. W. Cheng ◽  
W. P. Li
Keyword(s):  
Soil Moisture ◽  
Tibetan Plateau ◽  
Environmental Factors ◽  
Spatial Pattern ◽  
Aboveground Biomass ◽  
Alpine Meadow ◽  
Alpine Grassland ◽  
Critical Factors ◽  
Alpine Steppe ◽  
Habitat Factors

Abstract. Tibetan Plateau – the third pole of the world, with its extremly harsh and fragile ecological environment, is so sensitive to global change that it attracts many scientists' attention. Alpine grassland here is an important component of the global carbon cycle. Many studies have examined links between environmental factors and distribution of biomass, but little showed the critical environmental factors affecting the distribution of biomass. To document the general relationships between the habitat factors and aboveground biomass (AGB) in Tibetan Plateau, and to identify the critical factors for the distribution of AGB in the alpine steppe and meadow, the data of AGB and habitat factors from 110 field sites across the widely distributed alpine steppe and meadow of the plateau were compiled and analyzed with the classification and regression tree (CART) model, and the generalized additive model (GAM). The results showed that (1) the spatial pattern of AGB in alpine steppe was determined by six major environmental factors: soil organic carbon density of soil 0–30 cm depth (SOC1), longitude, mean annual precipitation (MAP), latitude, clay and soil moisture. As to the alpine meadow, the major factors were altitude, soil moisture, nitrogen, MAP and mean annual temperature (MAT). (2) As to the alpine steppe, increased SOC1, MAP and latitude were associated with increased AGB abundance, but increased longitude resulted in lower abundance of AGB. As to the alpine meadow, the distribution of AGB had strong negative relationships with altitude and soil moisture, but a positive correlation with soil nitrogen content across sites. The results suggested that the combined effects of meteorological factors, topographic factors, and soil factors were more significant for the spatial pattern of AGB in Tibetan Plateau. In addition, our work highlights the importance of further studies to seek effects of slope and aspect in alpine grassland.

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.

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