Humans have moved plants around the planet for centuries, both on purpose and by accident. Today, more than 16,000 vascular plant species have naturalized outside their native ranges. Most of this spread has occurred since the 1950s, particularly in regions with the greatest human footprint.

Some of these newcomers establish themselves quietly. Others become invasive, outcompeting native flora and reshaping ecosystems.

But what separates the cosmopolitan climbers from the homebodies? Are successful invaders simply taking advantage of empty niches abroad, or do they already have the right stuff at home?

An international team led by the University of Konstanz tested a deceptively simple idea: plant species that are thriving and expanding within their native habitats are the same ones most likely to take off overseas.

Europe’s role in global spread

Europe is one of the world’s main exporters of naturalized plants, making it an ideal proving ground.

The researchers compiled decades of distribution records for 3,920 native plant species across ten European regions (countries or subregions). They then reconstructed where each species occurred in an earlier period and where it occurred in a later one.

From those snapshots, they calculated an “occupancy-change” index – essentially, whether a species spread across more grid cells than you’d expect given where it started.

Then they compared that native-range trajectory to how widely each species has naturalized globally, using a two-part model that accounts for both whether a species naturalizes at all and how many regions it colonizes if it does.

Widespread plants spread farther

Two signals popped out across nearly all the regions. First, species that were already widespread in the early time period were more likely to show up as naturalized aliens elsewhere, and to do so in many regions.

Second, species that increased their footprint at home tended to be the very ones that spread abroad – nine of ten regions showed a positive link between “doing better at home” and “going farther away.”

In three regions – the Czech Republic, the Netherlands, and Switzerland – the effect was particularly strong for species that started out common and then expanded further.

Together, the results suggest that the same biological advantages helping a plant proliferate in its native landscape – tolerance for varied habitats, strong dispersal, flexible life histories – also prime it for success overseas.

Growth at home signals risk

A striking aspect of the study is that it didn’t rely only on static traits like range size. Many past analyses have shown that widely distributed species are more likely to naturalize.

Here, the “change” dimension mattered too: recent expansions at home carry predictive power, hinting that real-time monitoring of native-range dynamics can flag future invaders before they boom abroad.

The association with change was slightly weaker than the link with initial commonness. This was partly because some already-ubiquitous species had little room left to expand on paper. Even so, the pattern was robust across datasets assembled with different time windows and methods.

Traits of global plant invaders

So what do these winners look like? Broadly, they are big, versatile generalists that thrive in nutrient-rich, human-influenced habitats and compete well. Those traits help them occupy many places at home – and the same traits travel well.

The team also tested “woodiness” (tree or shrub vs. herb) as a coarse biological marker. Woodiness was often associated with increases in native occupancy. Long-lived plants can persist as conditions shift.

However, woody species that did naturalize tended to do so in fewer regions than herbs. This is likely because they reproduce more slowly and are introduced less often.

The nuance underscores that there isn’t one recipe for success, but a cluster of advantages that often co-occur.

Tracking plants can guide action

If the plant species expanding in their home habitats are the ones most likely to naturalize – and sometimes become invasive – elsewhere, then tracking native-range dynamics becomes a powerful early-warning tool.

Agencies can prioritize surveillance and biosecurity around species currently on the rise in their native regions. This is especially true for species flourishing in disturbed, nutrient-enriched settings that mirror many human-dominated landscapes worldwide.

For exporters and importers, the findings argue for tighter scrutiny of horticultural and trade pathways that disproportionately move “successful” species.

The study also reframes a persistent debate: Are invaders opportunists exploiting empty ecological space, or are they simply robust competitors wherever they go?

The answer, at least for many European exporters, leans toward the latter. Species that are common and spreading don’t succeed abroad because foreign ecosystems are uniquely vulnerable; they succeed because they are already built to win.

Native plant booms predict global spread

There’s an urgency to this work. Extinction risks are rising, but so is biotic homogenization – the gradual replacement of distinctive local floras with the same set of hardy generalists.

Watching which native plants are surging in their original habitats can help managers anticipate and mitigate that trend. Because policy resources are finite, insights like these can direct limited testing, regulation, and restoration budgets toward the species and pathways that matter most.

The bottom line is elegantly practical: If you want to know which plants will spread worldwide next, look first at which ones are spreading at home.

For Europe’s flora, that simple lens predicted global outcomes with surprising consistency. It also offers a blueprint any region can adapt.

The steps are straightforward: gather good time-series data on native occupancy, calculate change, and connect those trends to known naturalizations. Do that, and tomorrow’s invaders may not catch you by surprise.

The study is published in the journal Nature.

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