Soil moisture threshold of methane uptake in alpine ecosystems

Methane (CH4) uptake in alpine ecosystems is an important component of the global CH4 sink. However, large uncertainties remain regarding the magnitude and spatial patterns of CH4 uptake, owing to its extensive spatial variability, diverse controlling factors, and limited regional-scale observations. Here, we investigated field ecosystem CH4 uptake along a 3,200-km transect across various alpine grasslands on the Qinghai-Tibetan Plateau (QTP). We found a substantial spatial variation in in-situ CH4 uptake among alpine grasslands, with the highest rates in drier regions of the mid-western QTP. Soil moisture was the most important factor controlling CH4 uptake, exhibiting a remarkably low threshold of 6.2 ± 0.1 v/v %. Below this threshold, CH4 uptake was constrained by soil moisture, moisture-induced nitrogen limitation, and high temperatures. Above this threshold, CH4 uptake was mainly limited by gas diffusion and low temperatures. By integrating grid predictors with a random forest mode..., Study area and sampling sites
This study was conducted on the Qinghai-Tibetan Plateau (QTP), the highest and largest plateau on the Earth, with an average altitude of over 4,000 m above sea level and a broad area of 2.5 × 106 km2 . During July-August 2020, 58 sites were visited once across the QTP along a precipitation transect (mean annual precipitation (MAP): 56−712 mm yr -1, mean annual temperature (MAT): −7−5℃) of 3,200 km from northwest to southeast, covering all alpine grassland types. The grassland type at each site was defined according to the Chinese Vegetation map and through observations of the vegetation composition in the field.
Field measurements and sampling
To monitor in-situ CH4 fluxes, we randomly selected three to six 1 m × 1 m quadrats within a 10 m × 10 m plot at each site. CH4 fluxes were measured for 3−6 replicates within each quadrat using an opaque chamber during the daytime between 9:00 a.m. and 12:00 a.m. Specifically, in each quadrat, a cylindrical ..., , # Data from: Soil moisture threshold of methane uptake in alpine ecosystems

[https://doi.org/10.5061/dryad.tb2rbp06v](https://doi.org/10.5061/dryad.tb2rbp06v)

Here is the dataset used for the paper \"Soil moisture threshold of methane uptake in alpine ecosystems\"

## Description of the data and file structure

The dataset includes information on all sampling sites, including climate, plant, soil and microbial properties.

This dataset includes:

1\) Filed_and_lab_data.xlsx:Field and lab data of CH4 flux, climate, plant, soil,and microbial properties of each site along the transect;

2\) CH4_predictions_2001-2021_monthly.zip: CH4 prediction data at monthly step from 2001 to 2021;

3\) R code of Random Forest model for model building and regional predictions of CH4 flux.

All the data were collected from 58 sites along a 3,200 km transect across various alpine grasslands on the Qinghai-Tibetan Plateau (QTP). The field survey and sampling took place during July and August 2020. For the ex...,