Water and heat availability are drivers of the aboveground plant carbon accumulation rate in alpine grasslands on the Tibetan Plateau

Abstract

Aim: Climate change is expected to have important effects on plant phenology and carbon storage, with further shifts predicted in the future. Therefore, we proposed the community carbon accumulation rate (CAR) from the start of the growing season (SOS) to the peak of the growing season (POS) to fill the gap that the dynamic interactions between plant phenology and plant carbon research. Location: Tibetan Plateau.Major taxa: Alpine grassland plants. Time period: 2015.Methods: We conducted a transect survey across grasslands to measure community aboveground net primary production and carbon concentration. Additionally, phenology indicator data (SOS and POS) were extracted from the Global Inventory Modeling and Mapping Studies (GIMMS) normalized difference vegetation index version 3 database. Next, we used 'changepoint' analysis to detect the patterns of CARs, and performed linear regression and one-way ANOVA to explore the

Concurrent and Lagged Effects of Extreme Drought Induce Net Reduction in Vegetation Carbon Uptake on Tibetan Plateau

“…The favourable water and heat conditions, such as abundant soil moisture and mineral elements that are salutary for the vegetation net carbon uptake, provided important resources for vegetation growth [4,[60][61][62][63][64]. The soil water supply determines whether the vegetation photosynthesis operates normally when the CO2 concentration and light are sufficient [4,21,60]; thus, increased precipitation played a crucial role in ameliorating the vegetation net carbon uptake (Figures 4e and S3a). Additionally, soil water is an indispensable intermediary that guarantees the transportation of nutrients [60], which seems to support our findings regarding the NRVCU on the TP (Figure 4a).…”

“…The increase in temperature facilitates vegetation growth without encountering water limitations [59]. In addition, climate warming can stimulate the enzymatic activities of photosynthesis [60,65], with an evident promotion in the vegetation net carbon uptake. The increase in soil respiration as the climate warms is suitable for plant productivity due to the acceleration of mineralisation and the decomposition of organic matter [60,66,67], which explained why the NRVCU gradually declined (Figure 4a).…”

“…In addition, climate warming can stimulate the enzymatic activities of photosynthesis [60,65], with an evident promotion in the vegetation net carbon uptake. The increase in soil respiration as the climate warms is suitable for plant productivity due to the acceleration of mineralisation and the decomposition of organic matter [60,66,67], which explained why the NRVCU gradually declined (Figure 4a). Finally, an increased temperature may extend the length of the vegetative growing season [60,68], which is responsible for an increase in plant productivity, thereby restraining the NRVCU.…”

“…The increase in soil respiration as the climate warms is suitable for plant productivity due to the acceleration of mineralisation and the decomposition of organic matter [60,66,67], which explained why the NRVCU gradually declined (Figure 4a). Finally, an increased temperature may extend the length of the vegetative growing season [60,68], which is responsible for an increase in plant productivity, thereby restraining the NRVCU. In general, although a few studies have shown a downward trend of precipitation at individual meteorological station [69], the general improvements in the water and heat conditions visibly enhanced the capacity of the vegetation net carbon uptake on the TP (Figure 4a,c-g, Figure S3a-c).…”

“…The soil water supply determines whether the vegetation photosynthesis operates normally when the CO 2 concentration and light are sufficient [4,21,60]; thus, increased precipitation played a crucial role in ameliorating the vegetation net carbon uptake (Figures 4e and S3a). Additionally, soil water is an indispensable intermediary that guarantees the transportation of nutrients [60], which seems to support our findings regarding the NRVCU on the TP (Figure 4a). In addition to water, temperature is another climate variable affecting the vegetation net carbon uptake (Figures 4f and S3b).…”