The responses of microbial necromass carbon accumulation to climate aridity in alpine meadow soils are dominated by plant species richness
Data files
Jan 20, 2025 version files 36.17 KB
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Dataset_for_microbial_necromass_C.xlsx
32.87 KB
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README.md
3.30 KB
Abstract
Plant diversity loss caused by climate change decreases soil organic carbon (SOC) sequestration, but the mechanism involved remains unclear. Investigating the changes in soil microbial necromass carbon (MNC) accumulation along a climate–plant species diversity gradient can help clarify this mechanism, as it is crucial for the stability of SOC.
We conducted large-scale sampling across a 2500-km transect through grasslands on the Tibetan Plateau to investigate the MNC content and its contribution to SOC at depths of 0–20 cm and 20–40 cm in response to environmental and plant species diversity gradients.
Plant species richness, plant biomass, and the proportion of aboveground biomass accounted for by Cyperaceae (sedges) increased with decreasing aridity along the gradient of rising altitude. Meanwhile, the MNC content, its contribution to SOC, and the ratio of fungal to bacterial necromass carbon in both soil layers also increased with decreasing aridity. These results indicate that, in addition to changing climate factors along the altitudinal gradient, plant species richness plays a pivotal role in facilitating soil MNC accumulation and thus the accrual of SOC. Structural equation modeling revealed that plant diversity increases the MNC content by enhancing the abundance of Cyperaceae in the grassland. Higher abundance of Cyperaceae significantly increased the root biomass and level of rhizodeposition, thereby increasing the diversity and activity of soil microbes, and ultimately the accumulation of MNC.
Synthesis: We conclude that changes in plant species richness in response to aridity dominate the MNC content and its proportion in SOC on the Tibetan Plateau. These findings demonstrate the importance of incorporating plant species diversity into conservation efforts in grasslands to mitigate the negative impacts of climate change and human activities on SOC.
README: The responses of microbial necromass carbon accumulation to climate aridity in alpine meadow soils are dominated by plant species richness
https://doi.org/10.5061/dryad.t1g1jwtcg
Description of the data and file structure
From 15 July to 12 August 2022, we conducted an extensive field survey along a 2500-km transect that stretched from the southeastern to the northwestern parts of the Tibetan Plateau. There were 30 sites in total (each 100 m × 100 m; slope < 5°), at which we collected plant and soil samples. we randomly selected three 1 m × 1 m plots that were separated by a minimum distance of 25 m. All sites had been overgrazed and not fertilized, with no significant accumulation of litter on the soil surface. For each plot, we defined the plant species richness as the number of species, then clipped all plants in the plots at ground level and placed the samples into paper bags for transportation to the lab for weighing. Plants were categorized into three functional groups: grasses (Gramineae), sedges (Cyperaceae), and others. Root biomass was collected in the same plots using a root auger with an inner diameter of 7.5 cm at depths of 0–20 cm and 20–40 cm. After carefully washing away the soil, dead roots were identified based on their internal color and removed from the sample. Both shoot and root samples were oven-dried at 65°C until they reached a stable weight, and then their weights were recorded.
Soil samples were collected using a 3-cm-diameter auger at six points within each plot at 20-cm intervals to a depth of 100 cm. Collection depths were sometimes shallower at sites with a low depth to the bedrock. Soil subsamples from comparable depths within each of the six samples were pooled to form a composite sample. After removing litter and stones, samples were passed through a 2-mm sieve and then split into two parts. Approximately 100 g of fresh soil was kept at 4°C for measuring soil microbial properties. The remaining sample (about 800 g) was air-dried for amino sugar and soil physicochemical analyses. Only samples from 0–20 cm and 20–40 cm were analyzed for amino sugars and soil physicochemical properties due to the high cost of these analyses.
Files and variables
File: Dataset_for_microbial_necromass_C.xlsx
Description:
Abbreviations | ||
---|---|---|
S | Site | |
PSR | Plant species richness | |
SB | Shoot biomass | |
Sedges | Sedges (% of shoot biomass) | |
Grasses | Grasses (% of shoot biomass) | |
Others | Others (% of shoot biomass) | |
SOC | Soil organic carbon | |
MBC | Microbial biomass carbon | |
MNC | Microbial necromass carbon | |
FNC | Fungal necromass carbon | |
BNC | Bacterial necromass carbon | |
MBN | Microbial biomass nitrogen | |
MBP | Microbial biomass phosphorus | |
PH | Soil pH |
Code/software
Excel can open and view the datas.
Methods
From 15 July to 12 August 2022, we conducted an extensive field survey along a 2500-km transect that stretched from the southeastern to the northwestern parts of the Tibetan Plateau. There were 30 sites in total (each 100 m × 100 m; slope < 5°), at which we collected plant and soil samples. The sites spanned a wide range of geographic and climatic conditions, with longitudes ranging from 90°11’E to 102°42’E, latitudes ranging from 32°53’N to 38°59’N, and elevations ranging between 2750 and 4357 m. Soils were categorized as Cambisols, with some Loess-derived Luvisols, following the classification system established by the World Reference Base for Soil Resources (Schad, 2018), with pH values in the top 20 cm ranging from 5.78 to 9.18.
At each site, we randomly selected three 1 m × 1 m plots that were separated by a minimum distance of 25 m. All sites had been overgrazed and not fertilized, with no significant accumulation of litter on the soil surface. For each plot, we defined the plant species richness as the number of species, then clipped all plants in the plots at ground level and placed the samples into paper bags for transportation to the lab for weighing. Plants were categorized into three functional groups: grasses (Gramineae), sedges (Cyperaceae), and others. Root biomass was collected in the same plots using a root auger with an inner diameter of 7.5 cm at depths of 0–20 cm and 20–40 cm. After carefully washing away the soil, dead roots were identified based on their internal color and removed from the sample. Both shoot and root samples were oven-dried at 65°C until they reached a stable weight, and then their weights were recorded.
Soil samples were collected using a 3-cm-diameter auger at six points within each plot at 20-cm intervals to a depth of 100 cm. Collection depths were sometimes shallower at sites with a low depth to the bedrock. Soil subsamples from comparable depths within each of the six samples were pooled to form a composite sample. After removing litter and stones, samples were passed through a 2-mm sieve and then split into two parts. Approximately 100 g of fresh soil was kept at 4°C for measuring soil microbial properties. The remaining sample (about 800 g) was air-dried for amino sugar and soil physicochemical analyses. Only samples from 0–20 cm and 20–40 cm were analyzed for amino sugars and soil physicochemical properties due to the high cost of these analyses.