Vegetation resistance to increasing aridity when crossing thresholds depends on local environmental conditions in global drylands

Abstract

The crossing of aridity thresholds triggers abrupt changes in multiple functional and structural ecosystem attributes across global drylands. While we understand the consequences associated with aridity thresholds, the key factors influencing dryland vegetation resistance when crossing them remain unclear. Here, we used field observations from 58 dryland sites across five continents and satellite remote sensing data (2000-2022) to show that plant richness, soil moisture dynamics and texture, and bare soil fraction are important variables contributing to vegetation resistance. Additionally, drought history (frequency and magnitude of past droughts) is important in interaction with plant richness and soil texture. Interestingly, plant species richness was negatively related to vegetation resistance, except in areas with higher drought history and in grasslands. Our results highlight that vegetation resistance depends on local environmental conditions. Enhancing our understanding of the factors important for vegetation resistance is an important step towards dryland conservation efforts and sustainable management strategies.