Native plants can’t outrun climate change on their own

Across the United States, a quiet crisis is unfolding in forests, grasslands, and wetlands. Native plants, many of which have thrived in their home ecosystems for thousands of years, now face an impossible race.

Climate change is shifting temperature zones and seasonal patterns faster than these plants can naturally respond. Unlike animals, most plants cannot migrate quickly. Their slow dispersal, tied to seed movement and favorable growing conditions, means many will not survive unless we intervene.

Scientists and conservationists are grappling with a difficult question: Should we help these native species relocate? And if so, how do we do it responsibly?

The idea of helping plants move into nearby habitats, known as “managed relocation,” is gaining momentum. But moving plants is not without danger.

Many invasive species, which now plague American ecosystems, arrived in similar ways – carried by humans, intentionally or not, into places they never belonged.

Moving native plants may save them

Managed relocation sounds like a solution, but it comes with serious risks. The ecological scars of past mistakes remain. Kudzu, once planted for erosion control, now chokes forests.

Purple loosestrife clogs wetlands. Japanese honeysuckle overruns fields. All were introduced with good intentions. All became ecological threats.

Despite these examples, doing nothing could be worse. Climate projections show ecosystems changing rapidly, putting slow-moving native species at risk of extinction. Human-assisted movement might be their only shot.

Thomas Nuhfer is the lead author of a new study published in Global Change Biology and a graduate student in organismic and evolutionary biology at the University of Massachusetts Amherst.

​“We know that, because of climate, native species need to move,” said Nuhfer. “But many of the people working to manage invasive plant species have real concerns about unwittingly contributing to the problem if we start moving native species around.”

Assessing native plant traits

To solve this challenge, researchers need to understand what makes some plants thrive in new places and others wreak havoc.

This is where Nuhfer and his advisor, Professor Bethany Bradley, step in. Their new research examines how specific plant traits contribute to success (and potential risk) when relocating native species.

“We’ve made the mistake of introducing invasive species so many times in the past and we don’t want to keep making that mistake. But in a changing climate, doing nothing might do even more harm,” said Professor Bradley.

The team in Bradley’s lab has already shown that controlling invasive species is one of the strongest tools local communities can use to prepare for climate change. The researchers have tracked how invasive species numbers are rising rapidly.

In many ecosystems, plants and animals need to shift their range by at least 3.25 kilometers per year just to keep pace with warming temperatures and shifting seasons.

Good candidates for relocation

The study was focused on the traits that determine whether a plant can successfully relocate – and whether it will become a problem after doing so.

Traits like rapid growth, long flowering periods, and seed dispersal by wind often help plants survive in new environments. But these same traits have also been used to flag invasive species.

“We often use specific plant characteristics – like how quickly a plant grows, how long it flowers or whether its seeds can be spread by the wind – to determine its risk of becoming invasive,” said Nuhfer. “But these are also traits that could help a native species to survive in a new environment.”

The study draws from a wide range of literature in both restoration and invasion ecology. The researchers also reviewed the risk assessment tools used by land managers.

Their conclusion is that many traits promoting establishment are shared by both invasive and native species.

However, key differences emerge later – particularly when plants begin to spread. It’s in this phase that certain traits, such as size or toxicity, begin to distinguish potentially harmful species from those that simply need help surviving.

Drawing the line between help and harm

Some traits, like a high metabolic rate, support a plant’s ability to establish itself in new surroundings. These traits apply to both native species and invasive ones. But other traits, especially those linked to unchecked growth or ecosystem disruption, raise red flags.

Large size, for example, not only helps plants establish but also enables them to dominate landscapes. This can lead to overgrowth and displace local flora.

Toxicity is another trait of concern. While it doesn’t help a plant settle in, it allows it to repel herbivores and spread aggressively – potentially harming native species that share the habitat.

This creates a dilemma. If we avoid all traits associated with invasive species, we may end up ruling out the very traits that could help a plant survive. On the other hand, ignoring the signs of future invasiveness could create a new wave of ecological damage.

Changing the way we measure risk

The solution, according to the study, is not to ban all plants with certain traits but to refine our risk assessments.

Current tools used by land managers often take a one-size-fits-all approach. If a plant shares any trait with a known invasive, it may be excluded from relocation efforts. That overly cautious approach could undermine the entire strategy.

“Many of the current risk assessments that managers are using in the field are so risk-averse as to guarantee that managed relocation will fail,” said Professor Bradley.

“And if the relocation fails, then we’ve wasted all sorts of resources and haven’t helped native plants persist,” noted Nuhfer.

Instead, the researchers suggest focusing on traits that are most likely to lead to ecological harm – such as toxicity or seed dispersal by water – rather than those that simply help a plant get established.

A path forward in a warming world

This research, supported by the U.S. Geological Survey Northeast Climate Adaptation Science Center, marks a pivotal moment in conservation thinking.

As climate change accelerates, strategies that once seemed risky are now essential. Managed relocation, when guided by science and nuanced risk assessments, could help preserve the ecological heritage of countless regions.

By learning from past mistakes and using precise criteria, scientists and conservationists may strike a balance – helping native plants survive without repeating the errors that let invasive species flourish.

The stakes are high. But with thoughtful, evidence-based action, we can give native species a fighting chance in a changing world.

The study is published in the journal Global Change Biology.

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