Spatial threshold dataset for vegetation responses to active layer thickness in the Source Reach of the Yangtze River Basin, 1990–2024

This dataset contains figures supporting the spatial threshold analysis of vegetation responses to permafrost active layer thickening in the Source Region of the Yangtze River Basin (SRYRB). The figures illustrate the relationship between active layer thickness (ALT) and the NDVI change rate, and support the identification of the ecological threshold at which vegetation greening shifts from rapid increase to slowdown.

The uploaded files are derived from the spatial threshold analysis conducted in the manuscript. They are provided to support visualization and interpretation of the threshold detection results. The underlying point-level data are not publicly released in this dataset but are available from the corresponding author upon reasonable request.

Files included:

1. Figure_S1_Binned_ALT_NDVI_Threshold.png

This figure shows the binned relationship between ALT and NDVI change rate. ALT values were divided into continuous intervals using a fixed bin size of 0.05 m. The mean NDVI change rate within each ALT bin was calculated to reduce random point-scale fluctuations. A discontinuous piecewise linear regression model was then fitted to identify the break point in vegetation response to ALT.

2. Figure_S2_Original_Points_ALT_NDVI_Threshold.png

This figure shows the original spatial sample points used in the threshold analysis, together with the binned mean values. The grey points represent original samples extracted from the study area, while the black points represent binned mean NDVI change rates. This figure provides supporting evidence for the nonlinear relationship between ALT and vegetation greening.