Researchers from University of Massachusetts Amherst have studied the impact of plant nurseries in the spread of invasive species, especially in a warming climate, and we finally have numbers for the first time!

They published two papers that offer a comprehensive mapping of how 144 invasive species are expected to respond to temperatures increase in the eastern of the United States.

GOAL OF THE RESEARCH

Professor Bradley, a professor of Environmental Conservation at UMass Amherst, stated that managers have few resources to control invasions so it is important to focus on plants that are invasive or have the potential to become invasive. But this is a rather tricky matter.

Annette Evans, a postdoctoral at the same University , added “If we can proactively identify these species and the regions they are most likely to become abundant in as the climate warms, then we can head-off a major ecological threat before it’s too late.”

THE STUDY

The team studied 14 invasive species databases to pinpoint which species are abundant and where the hotspots occur. In the eastern of the US the hotspots are around the Great Lakes, the mid-Atlantic, and along the northeastern coasts of Florida and Georgia. More than 30 species are considered invasive in these regions.

They then ran the data on 144 plants through a series of models that predicted where the hotspots would occur under 2° Celsius of warming. These species will “move” towards the northeast by an average of 213 km (132 miles), and the hotspots will move with them.

A warmer weather will make currently unsuitable area more prone to abundant infestations of up to 21 new species and exacerbate the infestation of 40 current species. On the other hand, about 62% of the currently abundant species may find the new conditions inhospitable.

LINKS:

For Range Maps for individual species

State Specific Watch Lists

HOW PLANT NURSERIES COULD SEED INVASION

A second study, led by Evelyn M. Beaury, a postdoctoral researcher at Princeton, highlighted the role of commercial nurseries in the spread of invasive species. Doctor Beaury says “When people think of how invasive plant species spread, they might assume species are moving because of birds or the wind dispersing seeds, but commercial nurseries that sell hundreds of different invasives are actually the primary pathway of invasive plant introduction.”

How often invasives are sold in the same area in which they are abundant? And how might nurseries be exacerbating the problem of climate-driven invasion? The answer? A lot.

On a sample of 672 nurseries selling a total of 89 invasive species, they found that “nurseries are currently sowing the seeds of invasion for more than 80% of the species studied. If left unchecked, the industry could facilitate the spread of 25 species into areas that become suitable with 2°C of warming.”

“Furthermore, 55% of the invasive species were sold within 21 kilometers (13 miles) of an observed invasion—the median distance people across the U.S. go to buy landscaping plants. In other words, everyday gardeners who buy plants at their local nurseries could unwittingly help perpetuate invasion and associated ecological harm in their literal backyards.”

The good news? With these numbers finally available it’s the time to be proactive!

LINKS:

Regional Invasive Species

Invasive plants Fact Sheet (DCNR)

Pennsylvania DCNR invasive plant list

Gardenalia blog-invasive species are among us

Resources:

https://www.umass.edu/news/article/study-finds-plant-nurseries-are-exacerbating-climate-driven-spread-80-invasive-species

https://www.umass.edu/news/article/invasive-plants-are-still-sale-garden-ornamentals-research-shows

https://onlinelibrary.wiley.com/doi/10.1111/ddi.13787