Over the past few decades, ecological experiments have demonstrated that biodiversity enhances ecosystem stability amid environmental disturbances—findings that have profoundly shaped global awareness of the importance of biodiversity conservation. Yet one fundamental question remains unresolved: Does the relationship between biodiversity and ecosystem stability depend on the duration of ecosystem observation?

This issue has garnered growing attention and debate, particularly as long-term biodiversity experiments—such as the Cedar Creek experiments in the U.S. and Germany's Jena Experiment—have recently revealed that the stabilizing effect of plant diversity strengthens over time. Until now, however, this pattern had never been empirically validated in natural ecosystems.

To address this gap, a research team led by Prof. NIU Shuli from the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences, in collaboration with international partners, conducted a 4,200-kilometer survey across the alpine grasslands of the Qinghai-Tibet Plateau. By integrating regional survey data with global datasets on plant diversity and productivity, the team provided the first empirical evidence that biodiversity's stabilizing effects shift over time in natural ecosystems. The study was recently published in Nature Plants.

The researchers identified a clear, consistent temporal pattern across both regional and global scales: the stabilizing effect of plant diversity on ecosystem productivity grows stronger as observation periods lengthen, reaching saturation at approximately 10 to 13 years. This decadal threshold is critical, as longer time series capture climate-driven fluctuations in populations and communities that short-term studies fail to detect.

Furthermore, the team found that phylogenetic diversity—the evolutionary divergence among coexisting species—was the strongest predictor of long-term stability, explaining up to 36.2% of the variation. This outperformed taxonomic diversity, functional diversity, and even environmental factors. The researchers noted that this highlights phylogenetic diversity as a key, representative dimension of biodiversity that sustains ecosystem functioning over decades.

These findings emphasize the need for ecological observations lasting at least a decade to fully understand how biodiversity stabilizes ecosystems amid real-world environmental variability.