Invasive Amaranthus weeds predicted to shift across China as climate changes

Three invasive Amaranthus weed species could reshape their footprints across China as the climate changes, according to a new modeling study published in BMC Ecology and Evolution. Researchers simulated the potential distributions of Amaranthus blitum, A. spinosus and A. palmeri under current and future climate scenarios, finding that each species responds to distinct climatic drivers and is projected to shift in a different direction as conditions warm.

The models performed strongly in the study’s evaluation, with area under the curve values of 0.948 for A. blitum, 0.926 for A. spinosus and 0.928 for A. palmeri. Variable importance differed among the three species. Temperature Seasonality (BIO4) emerged as the primary factor influencing the distribution of A. blitum, while the distribution of A. spinosus was mainly driven by both Temperature Seasonality and Annual Precipitation (BIO12). For A. palmeri, the key determinants were Precipitation Seasonality (BIO15) and elevation. These differences suggest that a single management approach calibrated to one species may not transfer neatly to its relatives.

Under current climate conditions, the highly suitable areas for A. blitum and A. spinosus are concentrated in South and Southwest China, whereas the highly suitable areas for A. palmeri are primarily distributed in the North China Plain. This geographic split means that different regions of the country face different invasion risks today, and that monitoring priorities may need to vary by region and by species rather than treating the three weeds as a single threat.

The future projections reveal notably different trajectories. The suitable areas for A. blitum showed a high degree of climate envelope conservatism, with the distribution centroid displaying only a slight localized southwestward fluctuation around its original distribution. In other words, this species’ modeled range appears relatively stable under changing climates, at least in the scenarios examined.

A. spinosus followed a different pattern. Its suitable areas showed a slight overall expansion toward the northeast, and its centroid showed signs of retreating southwestward under the SSP585 scenario for the 2070s. That combination of range expansion in one direction and centroid retreat in another illustrates how distribution summaries can diverge depending on whether one tracks total suitable area or the center of gravity of the range.

The most dramatic projected change belonged to A. palmeri, which showed a significant and long-distance shift northwestward, a movement the authors link strongly to changing thermal conditions. Because A. palmeri is currently concentrated in the North China Plain under present-day conditions, a northwestward migration under future scenarios would carry its potential range into regions that have so far seen less of this species, raising the prospect of new areas becoming climatically suitable.

The Amaranthus genus, which belongs to the Amaranthaceae family and includes approximately 70 species globally, poses a significant risk of biological invasion in China, according to the study’s background. The three species examined here are already established invaders, and understanding where their suitable climates sit today and where they may move is central to anticipating future management burdens.

The authors frame their findings as a basis for proactive rather than reactive responses. The study, they conclude, revealed the spatiotemporal dynamics of the three invasive Amaranthus species under current and future climate scenarios and provides a scientific basis for developing early warning management response strategies for these invasive species in China. In practical terms, the differing drivers and projected shifts mean that surveillance networks might need to watch South and Southwest China for stability or modest change in A. blitum and A. spinosus, while paying particular attention to northwestern regions where A. palmeri’s suitable climate appears headed.

As with all species distribution modeling exercises, the projections describe climatic suitability rather than confirmed occurrences, and the study is a simulation of potential distributions under specified scenarios rather than an observation of range changes that have already happened. The work was published open access on 13 October 2026, and the early-release version notes that it remains subject to further edits before the final Version of Record. Even so, the contrast among the three species, one conservative, one modestly expanding, and one shifting long-distance, offers a concrete template for prioritizing where China’s response to these invasive amaranths is likely to be needed first.

Subject of Research: Species distribution modeling of three invasive Amaranthus weeds in China under current and future climate scenarios

Article Title: Predicting the invasion distribution of three Amaranthus species (Amaranthus blitum, A. spinosus and A. palmeri) under the current and future climate change scenarios in China

Article References: Hu, R., Li, Q., Wang, Z., Zheng, F., Xu, G., Clements, D. R., Yao, B., Jin, G., Yang, S., Shen, S., Zhang, F., & Day, M. D. (2026). Predicting the invasion distribution of three Amaranthus species (Amaranthus blitum, A. spinosus and A. palmeri) under the current and future climate change scenarios in China. BMC Ecology and Evolution. https://doi.org/10.1186/s12862-026-02596-8

Image Credits: AI Generated

DOI: 10.1186/s12862-026-02596-8

Keywords: Amaranthus, invasive species, climate change, species distribution modeling, China, Amaranthus palmeri, Amaranthus blitum, Amaranthus spinosus, SSP585, biological invasion, ecological niche modeling, weed management