scholarly journals 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

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.

scholarly journals Direct and Lagged Effects of Spring Phenology on Net Primary Productivity in the Alpine Grasslands on the Tibetan Plateau

2020 ◽  
Vol 12 (7) ◽  
pp. 1223 ◽  
Author(s):  
Zhoutao Zheng ◽  
Wenquan Zhu ◽  
Yangjian Zhang
Keyword(s):  
Tibetan Plateau ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Growing Season ◽  
The Tibetan Plateau ◽  
Ecosystem Productivity ◽  
Alpine Grasslands ◽  
Spring Phenology ◽  
Ecosystem Carbon ◽  
Lagged Effects

As a key biotic factor, phenology exerts fundamental influences on ecosystem carbon sequestration. However, whether spring phenology affects the subsequent seasonal ecosystem productivity and the underlying resource limitation mechanism remains unclear for the alpine grasslands of the Tibetan Plateau (TP). In this study, we investigated the direct and lagged seasonal responses of net primary productivity (NPP) to the beginning of growing season (BGS) along a precipitation gradient by integrating field observations, remote sensing monitoring and ecosystem model simulations. The results revealed distinct response patterns of seasonal NPP to BGS. Specifically, the BGS showed a significant and negative correlation with spring NPP (R = −0.73, p < 0.01), as evidenced by the direct boosting effects of earlier BGS on spring NPP. Moreover, spring NPP was more responsive to BGS in areas with more annual precipitation. The boosting effects of earlier BGS on NPP tended to weaken in summer compared with that in spring. Sequentially, BGS exhibited stronger positive correlation with autumn NPP in areas with less annual precipitation, which suggested the enhanced lagged suppressing effects of earlier spring phenology on ecosystem carbon assimilation during the later growing season under aggravated water stress. Overall, the strengthened NPP in spring was offset by its decrement in autumn, resulting in no obvious relationship between BGS and annual NPP (R = −0.34, p > 0.05) for the entire grasslands on the TP. The findings of this study imply that the lagged effects of phenology on the ecosystem productivity during the subsequent seasons should not be neglected in the future studies.

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

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.

Responses of net primary productivity to phenological dynamics in the Tibetan Plateau, China

2017 ◽  
Vol 232 ◽  
pp. 235-246 ◽  
Author(s):  
Siyuan Wang ◽  
Bing Zhang ◽  
Qichun Yang ◽  
Guangsheng Chen ◽  
Bojuan Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
The Tibetan Plateau

Aboveground biomass and seasonal patterns of aboveground net primary productivity in five bamboo species in northern Laos

2019 ◽  
Vol 13 (2) ◽  
pp. 150-156
Author(s):  
Singkone Xayalath ◽  
Isao Hirota ◽  
Shinsuke Tomita ◽  
Michiko Nakagawa
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Aboveground Biomass ◽  
Net Primary Productivity ◽  
Seasonal Patterns ◽  
Bamboo Species ◽  
Aboveground Net Primary Productivity ◽  
Sympatric Distribution ◽  
Carbon Sequestration Potential ◽  
Sequestration Potential

Abstract Aims Accurate estimates of bamboo biomass and net primary productivity (NPP) are required to evaluate the carbon sequestration potential of bamboo forests. However, relevant data that are important for climate change mitigation, have rarely been collected in regions outside of East Asia and India. Information on seasonal patterns of NPP and its components will enable the quantification of factors that influence the carbon balance in bamboo forests. In this study, we quantified the aboveground biomass (AGB) and aboveground NPP of five major bamboo species in northern Laos using monthly data collected over a 12-month period. Methods All live culms in 10, 2 m × 2 m plots (for one monopodial bamboo species: Indosasa sinica) and 30 clumps per species (for four sympodial bamboo species: Bambusa tulda, Cephalostachyum virgatum, Dendrocalamus membranaceus and Gigantochloa sp.) were numbered and measured at breast height. We set 10 or 20 litter traps per species to collect litterfall. Censuses of dead and recruited culms and litterfall collection were performed once per month for 12 months. Important Findings The AGB was highest in I. sinica (59.87 Mg ha−1) and lowest in C. virgatum (11.54 Mg ha−1), and was mostly below the plausible global range for bamboos (32–256 Mg ha−1). The sympatric distribution of multiple bamboo species at the study sites may have suppressed the AGB in four of the five studied species. The aboveground NPP estimates were between 3.43 and 14.25 Mg ha−1 yr−1; those for D. membranaceus (8.20 Mg ha−1 yr−1) and I. sinica (14.25 Mg ha−1 yr−1) were comparable to mean global estimates for temperate evergreen forests (8.78 Mg ha−1 yr−1) and tropical moist forests (10.56 Mg ha−1 yr−1). High culm recruitment rates (15.20–23.39% yr−1) were major contributors to aboveground NPP estimates. Seasonal patterns of aboveground NPP were largely influenced by the phenology of the new culms. In the four sympodial bamboo species, new culms began to emerge following the onset of persistent rainfall, mainly in July and August. However, the sprouting of new culms in the monopodial species I. sinica followed a trend of increasing temperatures, mainly in March and April. Thus, our results indicate that bamboos have considerable potential for sequestering carbon in northern Laos, but that this potential may be affected by climate change.

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