Global climate change is projected to lead to an increase in both the areal extent and degree of aridity in the world’s drylands. At the same time, the majority of drylands are located in developing countries where high population densities and rapid population growth place additional pressure on the ecosystem. Thus, drylands are particularly vulnerable to environmental changes and large-scale environmental degradation. However, little is known about the long-term functional response of vegetation to such changes induced by the interplay of complex human–environmental interactions. Here we use time series of satellite data to show how vegetation productivity in relation to water availability, which is a major aspect of vegetation functioning in tropical drylands, has changed over the past two decades. In total, one-third of tropical dryland ecosystems show significant (P < 0.05) changes in vegetation–rainfall sensitivity with pronounced differences between regions and continents. We identify population as the main driver of negative changes, especially for developing countries. This is contrasted by positive changes in vegetation–rainfall sensitivity in richer countries, probably resulting from favourable climatic conditions and/or caused by an intensification and expansion of human land management. Our results highlight geographic and economic differences in the relationship between vegetation–rainfall sensitivity and associated drivers in tropical drylands, marking an important step towards the identification, understanding and mitigation of potential negative effects from a changing world on ecosystems and human well-being.
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Increasing sensitivity of dryland vegetation greenness to precipitation due to rising atmospheric CO2
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The datasets analysed in this study are publicly available as referenced within the article. The data that support the findings of this study are available from the corresponding author upon reasonable request. Source data are provided with this paper.
The codes used in the data analysis to calculate SeRGS as well as potentially related drivers are available at https://github.com/Frangi10ne/SeRGS.
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This research is part of the project entitled title ‘Greening of drylands: Towards understanding ecosystem functioning changes, drivers and impacts on livelihoods’, which is financed by the Danish Council for Independent Research (DFF, Grant ID: DFF-6111‐00258). S.H. acknowledges the funding from the Belgian Federal Science Policy Office (Grant SR/00/339) and T.T. from the Swedish national Space board (SNSB Dnr 95/16). A.W.R.S. is partly funded on the ERC-2016-ADG HOPE project, W.D.K. on the eScience RETURN project, and A.M.A. was supported by the Swedish Research Council (Grant# 2018-00430).
The authors declare no competing interests.
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Abel, C., Horion, S., Tagesson, T. et al. The human–environment nexus and vegetation–rainfall sensitivity in tropical drylands. Nat Sustain 4, 25–32 (2021). https://doi.org/10.1038/s41893-020-00597-z
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