Hotspots of plant invasion change from subtropical towards temperate regions

The orange hawkweed is planted as a garden plant, and then sometimes escapes cultivation in large stands.
Photo Credit: © F. Essl

Scientific Frontline: Extended "At a Glance" Summary: Global Shifts in Plant Invasion Hotspots

The Core Concept: High-resolution global modeling of 9,701 alien plant species reveals that the geographical hotspots for plant invasion risk are shifting from subtropical zones toward temperate and polar regions due to climate change and land-use alterations.

Key Distinction/Mechanism: Unlike previous assessments based primarily on current botanical occurrences, this research utilizes advanced predictive modeling that integrates future climate and land-use scenarios through the 21st century. It identifies not only the geographical poleward shift of invasion risk but also predicts a substantial turnover in species composition, with new sets of heat-adapted alien plants replacing current flora in rapidly warming regions.

Origin/History: The findings were published in Nature Ecology & Evolution on March 27, 2026, by an international research team led by biodiversity researchers Ali Omer and Franz Essl from the Department of Botany and Biodiversity Research at the University of Vienna.

Major Frameworks/Components:

• High-Resolution Predictive Modeling: Utilization of global environmental variables and distribution data for 9,701 non-native species to map present and future invasion risks.
• Climate and Land-Use Scenarios: Projections extending to the end of the 21st century to assess the compounding impacts of the Anthropocene on global ecosystems.
• Geographical Shift Analysis: Tracking the contraction of invasion hotspots in hot, semi-arid subtropical regions and their subsequent expansion into previously unsuitable cold-climate zones, including Central Europe, boreal, and polar regions.
• Species Turnover Dynamics: Evaluating the compositional changes of non-native plant assemblages as ecosystems adapt to newly warmed environments.

Branch of Science: Ecology, Botany, Biodiversity Conservation, Environmental Science, and Climatology.

Future Application: The resulting high-resolution global maps will serve as a foundational tool for governments and conservationists to develop proactive, region-specific ecological management and biosecurity strategies, aiming to intercept and mitigate invasive species before they establish themselves in newly vulnerable territories.

Why It Matters: Alien plant species severely disrupt native ecosystems, reduce agricultural yields, and directly impact human health (e.g., the spread of highly allergenic ragweed). As invasion hotspots shift into densely populated temperate zones, biological invasions pose an escalating threat to global biodiversity and human livelihoods, necessitating precise, targeted mitigation efforts.

The heat-loving milkweed is increasingly spreading in the lowlands of Austria. It can form dense stands and then displace native species.
Photo Credit: © F. Essl

An international research team led by the University of Vienna has produced, for the first time, high-resolution global maps of invasion risk for thousands of alien plant species under current conditions and future climate and land use scenarios. Their results show that global hotspots of plant invasion risk will shift geographically, with temperate regions facing increasing risks, while risks may decline in some subtropical areas. The study was published in Nature Ecology & Evolution. 

The introduction of alien species into new regions by humans has become a defining signature of the Anthropocene, with an increasing number becoming widespread and exerting severe negative impacts on native species and human livelihoods. Many alien plants reduce agricultural yields, while others, such as allergenic ragweed, affect human health. Against this background, the researchers asked how global hotspots of plant invasion risk may change under future environmental conditions. 

About the study 

The researchers combined global data on alien plant distributions with environmental variables to model the invasion risk of 9,701 species. Using high-resolution data and robust modelling approaches, they assessed current patterns and projected future changes under different climate and land use scenarios until the end of the 21st century. 

Hotspots of plant invasion are centered in subtropical regions 

"Overall, we found that one third of the global land surface is currently suitable for at least 10 % of these alien species, making these areas invasion hotspots, where many alien plants are expected to occur", biodiversity researcher Ali Omer from the Department of Botany and Biodiversity Research at the University of Vienna and lead author of the study explains. He adds: "Most of these current hotspots are located in subtropical and warm temperate regions, including already large parts of Europe." 

Current hotspots of plant invasion will shift poleward 

"The results indicate that while the overall extent of hotspots may increase only moderately, their distribution will change substantially", explains biodiversity expert and senior author of the study Franz Essl, University of Vienna. This finding indicates that Europe belongs to the regions facing some of the highest invasion risks worldwide. 

Hotspots are expected to shift poleward into colder regions such as Central Europe and contract in increasingly hot and dry subtropical semi-arid regions. In Europe, species such as ragweed with its highly allergenic pollen and black locust, which invades forests and grasslands, are expected to become more widespread under a warming climate. Remote areas in boreal and polar regions are also projected to become more susceptible to plant invasions, causing rising negative impacts on these currently often untouched ecosystems. 

New set of alien plants replaces current alien plants 

"Not only the location of the invasion hotspots but also the identity of invading species is expected to change", Ali Omer highlights an important finding of the study. Under severe climate change, there may be little overlap between current and future assemblages of non-native plant species in some regions, indicating substantial species turnover. "We expect a new set of alien plant species adapted to warmer conditions to invade many regions", Essl adds. 

Rising impacts by alien plants are expected in many densely populated areas 

The study highlights the dynamic nature of plant invasions under global change. The shift of invasion hotspots towards densely populated temperate regions is likely to increase impacts on native biota and human well-being. This first high-resolution global assessment of invasion risk for thousands of alien plant species provides an important basis for developing proactive and region-specific management strategies to reduce the impacts of biological invasions under changing environmental conditions. 

Reference material: What Is: Invasive Species

Published in journal: Nature Ecology & Evolution

Title: The global geography of plant invasion risk under future climate and land-use changes

Authors: Ali Omer, Stefan Dullinger, Johannes Wessely, Bernd Lenzner, Adrián García-Rodríguez, Anna Schertler, Dietmar Moser, Andreas Gattringer, Amy J. S. Davis, Wayne Dawson, Trevor S. Fristoe, Matthias Grenié, Nicole L. Kinlock, Holger Kreft, Jan Pergl, Petr Pyšek, Mark van Kleunen, Patrick Weigelt, Marten Winter, Damaris Zurell, and Franz Essl

Source/Credit: Universität Wien

Reference Number: eco032726_01

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