Fig. 4: The global sensitivity of critical soil moisture thresholds to climate change depends on soil texture.
From: Global influence of soil texture on ecosystem water limitation
a, Predicted changes in global critical soil moisture thresholds (Δθcrit) in response to changes in VPD from current (2005–2014) to future (2060–2069) climate (SSP2-4.5 scenario). The four rectangles highlight regions where we expect the highest amplification of ecosystem vulnerability to drought due to increasing VPD. These regions will experience an increase in atmospheric drying, but show limited buffer capacity (small Δθcrit) due to the coarseness of their soil texture. Hyperarid deserts (dark grey, aridity index (AI) ≤ 0.05) were excluded. In humid regions (dotted area, AI > 1), where ecosystems are unlikely to be water limited, the impact of Δθcrit is likely to be negligible. b, The colours are mapped along the two axes representing the absolute changes in θcrit (y axis) and relative changes in potential transpiration rate (ΔTpot, x axis), respectively. Each pixel is mapped continuously in its opacity, from transparency (0% change) to full intensity (99% of all observations), while the colours change continuously from sand (red) to clay (yellow) based on the soil-texture-specific relationship between ΔTpot and Δθcrit (the colours stem from the 12 different soil textural classes; compare also the different slopes, for example, clay versus sand, to Fig. 1c). Warm colours (red–orange–yellow) indicate an increase (+Δθcrit) and cold colours (blue–green) indicate a decrease (−Δθcrit) in critical soil moisture thresholds.
