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# Shrub-mediated vertical coupling regulates Holocene ecosystem variability and transition dynamics

## Details

**Authors** Wang et al.

**Year** 2026

**Publisher** Communications Earth & Environment

**Discipline** Climatology

[Read it at the publisher](https://doi.org/10.1038/s43247-026-03877-2) 
10.1038/s43247-026-03877-2

## In authors' words

### Abstract

Ecosystems face amplified variability and abrupt reorganization under climate and land-use change, yet the role of vertical vegetation structure over millennia remains poorly constrained. Here we show, using Holocene pollen, charcoal, palaeoclimate and human-activity proxies from the Eastern China Monsoon Region, how tree, shrub and herb layers relate to ecosystem variability and potential tipping points. Shrubs are associated with reduced variability in northern temperate forest–grassland mosaics and southern subtropical forests, consistent with buffering that maintains continuity between canopy and ground layers. In the more open warm-temperate central region, shrub buffering is weak and lower variability depends mainly on a woody framework. Potential tipping points are asynchronous, with earlier transitions in the structurally weaker central region. As transitions are approached, shrubs shift from buffering variability to being linked with vegetation reorganization under intensifying fire, climatic stress and human activity. These results identify shrub-mediated vertical coupling as a key axis of long-term ecosystem stability. Shrubs stabilize long‑term ecosystem dynamics by buffering variability across vegetation layers but shift to drivers of reorganization under increasing fire, climate, and human pressures, based on Holocene pollen, charcoal, and paleoenvironmental analyses from the Eastern China Monsoon Region.

### What they found (results)

Analysis of Holocene pollen, charcoal, and paleoclimate proxy records from the Eastern China Monsoon Region found that shrubs normally buffer ecosystem variability by coupling canopy and ground vegetation layers, but under intensifying climate, fire, or human pressure this coupling reverses and shrubs become drivers of regional ecosystem tipping points.

## Commentary

### In short

A part of the whole system (the shrub layer) is shown to mediate the relationship between two other parts (canopy and ground vegetation), and the nature of that relationship itself can flip from stabilizing to destabilizing.

**Patterns it shows** S, R

**Added** 2026-08-01

**How to cite this** Wang et al. (2026). Shrub-mediated vertical coupling regulates Holocene ecosystem variability and transition dynamics. Communications Earth & Environment.