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Vegetation greening fails to boost ecosystem resilience in Northern Hemisphere, study finds

A recent study has unveiled a paradox across Eurasia: while vegetation has visibly flourished in recent decades, the underlying resilience of its ecosystems has simultaneously weakened. This finding challenges the prevailing narrative of environmental improvement and raises questions about the continent's future ecological stability. The study is in Ecological Indicators.

Led by Prof. Hao Xingming from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences, the researchers charted the ebb and flow of Eurasian ecosystem resilience from 1984 to 2020. Using "critical slowing down" (CSD) indicators—a sophisticated metric that quantifies a system's ability to recover from disturbances—they found that vegetation greening has coexisted with a significant loss of ecosystem resilience since 2005.

The study harnessed a wealth of multi-source vegetation indices, including data from the Global Inventory Monitoring and Modeling Studies (GIMMS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Orbiting Carbon Observatory-2 solar-induced chlorophyll fluorescence (GOSIF). This robust approach allowed researchers to validate the consistency of resilience indicators across different datasets, ensuring the reliability of their findings.

To pinpoint the driving forces behind these shifts, the researchers employed a sophisticated random forest model coupled with Shapley Additive Explanation (SHAP)—a cutting-edge technique for interpreting complex AI models.

"Our findings demonstrate that resilience estimates derived from various key vegetation proxies, including the Normalized Difference Vegetation Index (NDVI), kernel NDVI (kNDVI), Leaf Area Index (LAI), Gross Primary Production (GPP), and solar-induced chlorophyll fluorescence (GOSIF, which captures photosynthetic activity), exhibit remarkably consistent spatial patterns and trends," said Zhang Jingjing, the study's first author. This consistency underscores the robustness of the observed resilience decline.

The study identified the primary culprits behind this ecological vulnerability. In humid regions, rising temperatures emerged as a primary driver of resilience decline. Conversely, in arid regions, variability in water availability proved to be the dominant factor compromising the ecosystems' ability to bounce back from stress.

This study provides an indispensable reference for scientists and policymakers striving to comprehend the intricate relationship between vegetation dynamics and the inherent resilience of Eurasian terrestrial ecosystems.