Growth stage-dependent responses of carbon fixation process of alpine grasslands to climate change over the Tibetan Plateau, China

Community assembly and functional leaf traits mediate precipitation use efficiency of alpine grasslands along environmental gradients on the Tibetan Plateau

10.7287/peerj.preprints.2472v1 ◽

2016 ◽

Author(s):

Shaowei Li ◽

Jianshuang Wu

Keyword(s):

Climate Change ◽

Tibetan Plateau ◽

Community Assembly ◽

Environmental Gradients ◽

Diversity Index ◽

Regional Scale ◽

The Tibetan Plateau ◽

Alpine Grasslands ◽

Moisture Index ◽

Use Efficiency

The alpine grasslands on the Tibetan Plateau are sensitive and vulnerable to climate change. However, it is still unknown how precipitation use efficiency (PUE), the ratio of ANPP to precipitation, is related to community assembly of plant species, functional groups or traits for the Tibetan alpine grasslands along actual environmental gradients. We conducted a multi-site field survey at grazing-excluded pastures across meadow, steppe and desert-steppe to measure aboveground biomass in August, 2010. We used species richness, the Shannon diversity index, and cover-weighted functional group composition (FGC) of 1-xerophytes, 2-mesophytes, and 3-hygrophytes to describe community assembly at the species level; and chose community-level leaf area index (LAIc ), specific leaf area (SLAc ), and species-mixed foliar δ13C to quantify community assembly at the functional trait level. Our results showed that PUE decreased with increasing accumulated active temperatures (AccT) when daily temperature average is higher than 5°C, but increased with increasing climatic moisture index, which was demined as the ratio of growing season precipitation (GSP) to AccT. We also found that PUE increased with increasing species richness, the Shannon diversity index, FGC and LAIc ,decreased with increasing foliar δ13C, and had no relation with SLAc at the regional scale. Neither soil total nitrogen nor organic carbon has no influence on PUE at the regional scale. The community assembly of the Shannon index, LAIc and SLAc together accounted for 46.3 % of variance in PUE, whilst climatic moisture index accounted for 47.9 % of variance in PUE at the regional scale. This implies that community structural properties and plant functional traits can mediate the sensitivity of alpine grassland productivity in response to climate change. Thus, a long-term observation on community structural and functional changes is recommended for better understanding the response of alpine ecosystems to regional climate change on the Tibetan Plateau.

Download Full-text

Community assembly and functional leaf traits mediate precipitation use efficiency of alpine grasslands along environmental gradients on the Tibetan Plateau

PeerJ ◽

10.7717/peerj.2680 ◽

2016 ◽

Vol 4 ◽

pp. e2680 ◽

Cited By ~ 4

Author(s):

Shaowei Li ◽

Jianshuang Wu

Keyword(s):

Climate Change ◽

Tibetan Plateau ◽

Community Assembly ◽

Environmental Gradients ◽

Diversity Index ◽

Regional Scale ◽

The Tibetan Plateau ◽

Alpine Grasslands ◽

Use Efficiency ◽

Precipitation Use Efficiency

The alpine grasslands on the Tibetan Plateau are sensitive and vulnerable to climate change. However, it is still unknown how precipitation use efficiency (PUE), the ratio of aboveground net primary productivity (ANPP) to precipitation, is related to community assembly of plant species, functional groups or traits for the Tibetan alpine grasslands along actual environmental gradients. We conducted a multi-site field survey at grazing-excluded pastures across meadow, steppe and desert-steppe to measure aboveground biomass (AGB) in August, 2010. We used species richness (SR), the Shannon diversity index, and cover-weighted functional group composition (FGC) of 1-xerophytes, 2-mesophytes, and 3-hygrophytes to describe community assembly at the species level; and chose community-level leaf area index (LAIc), specific leaf area (SLAc), and species-mixed foliar δ13C to quantify community assembly at the functional trait level. Our results showed that PUE decreased with increasing accumulated active temperatures (AccT) when daily temperature average is higher than 5 °C, but increased with increasing climatic moisture index (CMI), which was demined as the ratio of growing season precipitation (GSP) to AccT. We also found that PUE increased with increasing SR, the Shannon diversity index, FGC and LAIc, decreased with increasing foliar δ13C, and had no relation with SLAcat the regional scale. Neither soil total nitrogen (STN) nor organic carbon has no influence on PUE at the regional scale. The community assembly of the Shannon index, LAIcand SLActogether accounted for 46.3% of variance in PUE, whilst CMI accounted for 47.9% of variance in PUE at the regional scale. This implies that community structural properties and plant functional traits can mediate the sensitivity of alpine grassland productivity in response to climate change. Thus, a long-term observation on community structural and functional changes is recommended for better understanding the response of alpine ecosystems to regional climate change on the Tibetan Plateau.

Download Full-text

Community assembly and functional leaf traits mediate precipitation use efficiency of alpine grasslands along environmental gradients on the Tibetan Plateau

10.7287/peerj.preprints.2472 ◽

2016 ◽

Author(s):

Shaowei Li ◽

Jianshuang Wu

Keyword(s):

Climate Change ◽

Tibetan Plateau ◽

Community Assembly ◽

Environmental Gradients ◽

Diversity Index ◽

Regional Scale ◽

The Tibetan Plateau ◽

Alpine Grasslands ◽

Moisture Index ◽

Use Efficiency

The alpine grasslands on the Tibetan Plateau are sensitive and vulnerable to climate change. However, it is still unknown how precipitation use efficiency (PUE), the ratio of ANPP to precipitation, is related to community assembly of plant species, functional groups or traits for the Tibetan alpine grasslands along actual environmental gradients. We conducted a multi-site field survey at grazing-excluded pastures across meadow, steppe and desert-steppe to measure aboveground biomass in August, 2010. We used species richness, the Shannon diversity index, and cover-weighted functional group composition (FGC) of 1-xerophytes, 2-mesophytes, and 3-hygrophytes to describe community assembly at the species level; and chose community-level leaf area index (LAIc ), specific leaf area (SLAc ), and species-mixed foliar δ13C to quantify community assembly at the functional trait level. Our results showed that PUE decreased with increasing accumulated active temperatures (AccT) when daily temperature average is higher than 5°C, but increased with increasing climatic moisture index, which was demined as the ratio of growing season precipitation (GSP) to AccT. We also found that PUE increased with increasing species richness, the Shannon diversity index, FGC and LAIc ,decreased with increasing foliar δ13C, and had no relation with SLAc at the regional scale. Neither soil total nitrogen nor organic carbon has no influence on PUE at the regional scale. The community assembly of the Shannon index, LAIc and SLAc together accounted for 46.3 % of variance in PUE, whilst climatic moisture index accounted for 47.9 % of variance in PUE at the regional scale. This implies that community structural properties and plant functional traits can mediate the sensitivity of alpine grassland productivity in response to climate change. Thus, a long-term observation on community structural and functional changes is recommended for better understanding the response of alpine ecosystems to regional climate change on the Tibetan Plateau.

Download Full-text

The Change in Environmental Variables Linked to Climate Change Has a Stronger Effect on Aboveground Net Primary Productivity Than Does Phenological Change in Alpine Grasslands

Frontiers in Plant Science ◽

10.3389/fpls.2021.798633 ◽

2022 ◽

Vol 12 ◽

Author(s):

Jiangwei Wang ◽

Meng Li ◽

Chengqun Yu ◽

Gang Fu

Keyword(s):

Climate Change ◽

Tibetan Plateau ◽

Carbon Cycling ◽

Primary Productivity ◽

Environmental Variables ◽

Net Primary Productivity ◽

Growing Season ◽

The Tibetan Plateau ◽

Aboveground Net Primary Productivity ◽

Alpine Grasslands

More and more studies have focused on responses of ecosystem carbon cycling to climate change and phenological change, and aboveground net primary productivity (ANPP) is a primary component of global carbon cycling. However, it remains unclear whether the climate change or the phenological change has stronger effects on ANPP. In this study, we compared the effects of phenological change and climate change on ANPP during 2000–2013 across 36 alpine grassland sites on the Tibetan Plateau. Our results indicated that ANPP showed a positive relationship with plant phenology such as prolonged length of growing season and advanced start of growing season, and environmental variables such as growing season precipitation (GSP), actual vapor pressure (Ea), relative humidity (RH), and the ratio of GSP to ≥5°C accumulated temperature (GSP/AccT), respectively. The linear change trend of ANPP increased with that of GSP, Ea, RH, and GSP/AccT rather than phenology variables. Interestingly, GSP had the closer correlation with ANPP and meanwhile the linear slope of GSP had the closer correlation with that of ANPP among all the concerned variables. Therefore, climate change, mainly attributed to precipitation change, had a stronger effect on ANPP than did phenological change in alpine grasslands on the Tibetan Plateau.

Download Full-text

Contrasting Evolution Patterns of Endorheic and Exorheic Lakes on the Central Tibetan Plateau and Climate Cause Analysis during 1988–2017

Water ◽

10.3390/w13141962 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1962

Author(s):

Zhilong Zhao ◽

Yue Zhang ◽

Zengzeng Hu ◽

Xuanhua Nie

Keyword(s):

Climate Change ◽

Tibetan Plateau ◽

Climatic Factors ◽

Global Climate ◽

Rapid Expansion ◽

Annual Precipitation ◽

The Tibetan Plateau ◽

Lake Area ◽

Climate Change Research ◽

Mean Temperature

The alpine lakes on the Tibetan Plateau (TP) are indicators of climate change. The assessment of lake dynamics on the TP is an important component of global climate change research. With a focus on lakes in the 33° N zone of the central TP, this study investigates the temporal evolution patterns of the lake areas of different types of lakes, i.e., non-glacier-fed endorheic lakes and non-glacier-fed exorheic lakes, during 1988–2017, and examines their relationship with changes in climatic factors. From 1988 to 2017, two endorheic lakes (Lake Yagenco and Lake Zhamcomaqiong) in the study area expanded significantly, i.e., by more than 50%. Over the same period, two exorheic lakes within the study area also exhibited spatio-temporal variability: Lake Gaeencuonama increased by 5.48%, and the change in Lake Zhamuco was not significant. The 2000s was a period of rapid expansion of both the closed lakes (endorheic lakes) and open lakes (exorheic lakes) in the study area. However, the endorheic lakes maintained the increase in lake area after the period of rapid expansion, while the exorheic lakes decreased after significant expansion. During 1988–2017, the annual mean temperature significantly increased at a rate of 0.04 °C/a, while the annual precipitation slightly increased at a rate of 2.23 mm/a. Furthermore, the annual precipitation significantly increased at a rate of 14.28 mm/a during 1995–2008. The results of this study demonstrate that the change in precipitation was responsible for the observed changes in the lake areas of the two exorheic lakes within the study area, while the changes in the lake areas of the two endorheic lakes were more sensitive to the annual mean temperature between 1988 and 2017. Given the importance of lakes to the TP, these are not trivial issues, and we now need accelerated research based on long-term and continuous remote sensing data.

Download Full-text