Reference data.xlsx
This study conducts a meta-analysis of 165 studies to examine vegetation and soil characteristics in varying degraded grasslands on the Qinghai-Tibet Plateau (QTP) and Inner Mongolia Plateau (IMP). It uses 11 indicators to assess grassland responses to degradation in these regions. We systematically collect peer-reviewed journal articles on changes in grassland vegetation and soil characteristics under different degrees of degradation on the QTP and the IMP through the Web of Science and the China National Knowledge Infrastructure up to June 2023. The search strategy combines keywords such as “degradation degrees/stages/gradients/levels”, “Qinghai-Tibet Plateau”, “Tibetan Plateau”, “alpine grassland”, “Inner Mongolia Plateau”, “Northern temperate grassland”, “vegetation characteristics” and “soil properties”. To ensure unbiased article selection, we apply the following criteria: (1) Studies conducted during the growing season on the QTP or the IMP with specific locations or coordinates, to ensure ecological similarity among sample points. (2) Articles must include both non-degraded grassland (NDG) as the control group and various degrees of degraded grassland as the treatment group, with the number of experiment repetitions specified. (3) The classification of grassland degradation should follow clear standards, and vegetation and soil data extraction units should be unified. (4) For studies with varying soil depths, only topsoil data are selected. In total, we select 165 articles that cover vegetation and soil characteristics across different degrees of grassland degradation on the QTP (120 articles) and the IMP (45 articles). These articles report data on at least one of the following 11 variables: above-ground biomass (AGB), below-ground biomass (BGB), vegetation height (VH), soil organic carbon (SOC), soil total nitrogen (STN), soil total phosphorus (STP), soil available nitrogen (SAN), soil available phosphorus (SAP), soil water content (SWC), soil pH, and soil bulk density (SBD). If the mean annual temperature (MAT) and the mean annual precipitation (MAP) are not provided in the original articles, we supplement the data from the global climate database (http://www.worldclim.org/) based on the study site's longitude and latitude. Elevation data are derived from the China Qinghai-Tibet Plateau Data Center (http://data.tpdc.ac.cn). We collect figure data and tabular data in two formats. Figure data are extracted using WebPlotDigitizer (version 4.3), and tabular data are directly imported into Excel. Using MetaWin 2.1 software (Sinauer Associates, Sunderland, USA), we entered the mean (X), standard deviation (SD), and sample size (N) for both the degraded and NDG groups from each article to calculate the effect value and 95% CI for each indicator.
