New study in US and Europe shows how invasive plant species fare better than natives

October 27, 2014 by AlisonĀ  SatakeĀ , Louisiana State University
New study in U.S. and Europe shows how invasive plant species fare better than natives

LSU ecologist James Cronin and colleague Laura Meyerson from the University of Rhode Island conducted an ambitious large-scale study on the native and invasive species of reed, Phragmites australis, in North America and Europe funded by the National Science Foundation. They found that the intensity of plant invasions by non-native species can vary considerably with changes in latitude.

"When looking at a continental scale invasion in particular, we can't assume that the invasion is uniform across the region because of latitudinal differences in species interactions like herbivore pressure and resistance to herbivory," said Meyerson, URI associate professor of habitat restoration ecology. "Some biogeographic regions may be more susceptible to invasions while others are more resistant.

Therefore it is important to look at invasions at a macro scale, such as for an entire continent, in order to accurately interpret the invasion process and the strength of its impacts.

"Our continental-scale biogeographic perspective allowed us to have some insights into the heterogeneity of invasions that are not possible for smaller scale studies," she said.

The research was published this month in the journal Ecology.

In their study of native and non-native sub-species of P. australis on both continents, they also found that herbivores feed upon the native Phragmites in North America at a much greater rate than on the invasive Phragmites.

"Our native Phragmites in North America is getting hammered by both native and introduced insects, whereas the invasive Phragmites in North America suffers far less herbivory than it does in its native Europe," she said. "That's partly because when invasives are introduced to a new place, they leave their enemies behind and can devote their resources to greater growth."

To determine whether differences occurred in resistance to herbivory, Meyerson and Cronin surveyed 13 patches of native Phragmites and 17 patches of non-native Phragmites along the East Coast from Canada to Florida. They conducted similar surveys of 21 patches of Phragmites in Europe from Norway to southern Portugal. (The native European species and the invasive non-native species in North America are the same lineage.)

At each site, Meyerson and Cronin measured plant biomass and defenses against herbivores and quantified the damage caused by galling, chewing, and sucking insects such as aphids to measure the effects of herbivory on Phragmites fitness. They found that chewing and galling insects consumed a greater quantity of the native and non-native plants in the southern part of North America, while aphids were more prevalent at higher latitudes.

"Interactions between herbivores and native plants were much stronger than interactions between herbivores and invasive plants at lower latitudes, making the southern region more susceptible to ," said Cronin, LSU Department of Biological Sciences professor. "This means that the suffer less herbivory at lower latitudes than the native plants, giving the invasive Phragmites a greater opportunity to invade. The pattern weakens at suggesting that herbivores may be more important in limiting invasion success in the north."

Based on their results, Meyerson and Cronin believe that efforts to identify an insect that could be used as an agent of biocontrol for the invasive Phragmites may do more damage to the native than to the invasive variety.

"Because we found that all of the insects perform better on the native than on the invasive type, it suggests to us that if a biocontrol is released in North America, it's going to harm the native Phragmites more than the invasive," they said. "Our data suggests that it would be ill- advised to release a biocontrol agent against Phragmites."

Explore further: Herbivores play important role in protecting habitats from invasive species

Related Stories

Galapagos invasion is global warning

September 3, 2014

A new study led by a PhD researcher at The University of Western Australia has revealed that parts of the iconic Galapagos Islands have been overrun by invasive plants from other parts of the world.

Recommended for you

Apple pivot led by star-packed video service

March 25, 2019

With Hollywood stars galore, Apple unveiled its streaming video plans Monday along with news and game subscription offerings as part of an effort to shift its focus to digital content and services to break free of its reliance ...

How tree diversity regulates invading forest pests

March 25, 2019

A national-scale study of U.S. forests found strong relationships between the diversity of native tree species and the number of nonnative pests that pose economic and ecological threats to the nation's forests.

Scientists solve mystery shrouding oldest animal fossils

March 25, 2019

Scientists from The Australian National University (ANU) have discovered that 558 million-year-old Dickinsonia fossils do not reveal all of the features of the earliest known animals, which potentially had mouths and guts.

Earth's deep mantle flows dynamically

March 25, 2019

As ancient ocean floors plunge over 1,000 km into the Earth's deep interior, they cause hot rock in the lower mantle to flow much more dynamically than previously thought, finds a new UCL-led study.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.