The responses of microbial necromass carbon accumulation to climate aridity in alpine meadow soils are dominated by plant species richness

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 ad..., 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 pla..., , # 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](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 wer...