Work

Desertification expansion significantly suppresses photosynthetic peak capacity of arid ecosystems at the global scale

Year: 2025

Type: article

Abstract: • A global high-resolution framework for analyzing desertification impacts on ecosystem photosynthetic peak. • Innovative application of the space-for-time substitution approach to assess GPP max dynamics. • Multi-source remote sensing evidence shows that desertification expansion significantly suppresses GPP max . • Ecosystems with higher initial GPP max incur greater functional losses under desertification. Arid ecosystems occupy about two-fifths of the global land surface, and fluctuations in their productivity play a pivotal role in global carbon sequestration and ecosystem service provision. However, the global-scale effect of desertification expansion on the annual maximum photosynthetic peak has not yet been systematically quantified. In this study, 30-m high-resolution desert cover data (GLCLUC) and multi-source remote-sensing photosynthetic indicators were integrated, using a space-for-time substitution framework to establish a global desertification scenario classification system. We quantitatively evaluated the influence of diverse desert expansion and contraction scenarios on the ecosystem photosynthetic peak (GPP max ). Results indicate that the average GPP max in high-intensity expansion regions (HIEs) is 8.23 g C m −2 8d −1 , whereas medium- to low-intensity expansion regions (MIEs) show a value of 8.95 g C m −2 8d −1 . By contrast, medium- to low-intensity contraction regions (MIRs) and high-intensity contraction regions (HIRs) demonstrate markedly higher GPP max values of 10.64 g C m −2 8d −1 and 17.64 g C m −2 8d −1 , respectively. Regarding the photosynthetic peak difference (ΔGPP max ), expansion scenarios (HIEs, MIEs) significantly decrease ecosystem photosynthetic potential, with average ΔGPP max reductions of 1.19–3.95 g C m −2 8d −1 relative to contraction scenarios (HIRs, MIRs). The most pronounced losses occur in South America, North America, and Eurasia, with South America exhibiting reductions exceeding 6 g C m −2 8d −1 . Additionally, ecosystems with initially higher photosynthetic potential experience greater GPP max declines under intense desert expansion. This study provides the first global-scale evidence revealing how different desertification pathways modify ecosystem photosynthetic peaks and their regional disparities, offering critical scientific support for ecological restoration, carbon sequestration strategies, and land management across arid landscapes.

Source: International Journal of Applied Earth Observation and Geoinformation

DOI: 10.1016/j.jag.2025.105042