Lack of plant diversity spurs cankerworm damage in cities

May 23, 2014 by Matt Shipman
Research from North Carolina State University shows that a lack of plant diversity is a key contributor to the widespread defoliation caused by fall cankerworms in cities. Credit: Steven Frank, North Carolina State University

Research from North Carolina State University finds that a lack of plant diversity is a key contributor to the widespread defoliation caused by cankerworms in cities, and highlights the role that increasing diversity can play in limiting future damage.

Fall cankerworms (Alsophila pometaria) are caterpillars that are native to the eastern United States and hatch in early spring. The cankerworms defoliate trees and other plants, eating new leaves as they emerge – which is both unsightly and can ultimately kill the plants.

"We see cankerworms doing more damage to trees in cities than in the wild and examples of widespread cankerworm damage are happening more often," says Dr. Steve Frank, author of a paper describing the work and an assistant professor of entomology at NC State. "We wanted to know why."

Frank looked at two aspects of that distinguish them from natural environments: the fact that urban environments have less diversity and density of plant life; and the fact that urban areas have more nonnative plant species, such as many ornamental shrubs.

To evaluate the impact of diversity and nonnative species on cankerworm damage, Frank focused on the damage cankerworms did to understory plants – those plants that grow near or under trees.

"I found that plays a significant role," Frank says. "Cankerworms did more damage in simple urban environments, where the understory consisted of only a few shrubs, than they did in more complex environments with greater plant diversity."

Frank also found a sharp distinction between the impact on native and nonnative plant species.

Native plants were hit particularly hard in simple urban environments. They benefited significantly from complex environments that more closely resembled natural habitat. Nonnative species were largely ignored by cankerworms, regardless of the setting.

"This does not mean that everyone should plant ," Frank says. "The take-home message is that we need to take steps to make urban environments more like in terms of plant diversity."

Explore further: Plant biodiversity under threat from general viruses

More information: The paper, "Bad neighbors: urban habitats increase cankerworm damage to non-host understory plants," is published online in the journal Urban Ecosystems. link.springer.com/article/10.1007%2Fs11252-014-0368-x

Related Stories

Plant biodiversity under threat from general viruses

May 12, 2014

(Phys.org) —Introduced generalist plant viruses from other hosts that encounter native plant species for the first time pose a greater threat to plant biodiversity in south-west Australia than introduced ...

Invasion of the slugs—halted by worms...

May 12, 2013

The gardener's best friend, the earthworm, is great at protecting leaves from being chomped by slugs, suggests research in BioMed Central's open access journal BMC Ecology. Although they lurk in the soil, they seem to pro ...

Cushion plants help other plants survive

Feb 18, 2013

Alpine cushion plants help other plants in harsh mountain environments to survive. This is shown by new research involving researchers from the University of Gothenburg, Sweden, the results of which are now ...

Biodiversity can flourish on an urban planet

Jan 23, 2014

Mention the word biodiversity to a city dweller and images of remote natural beauty will probably come to mind – not an empty car park around the corner. Wildlife, we think, should be found in wild places, ...

Recommended for you

Scientists say polar bears won't thrive on land food

15 hours ago

A group of researchers say polar bears forced off melting sea ice will not find enough food to replace their current diet of fat-laden marine mammals such as seals, a conclusion that contradicts studies indicating ...

Emu movements chronicled in seed dispersal project

17 hours ago

GPS technology attached to emus (Dromaius novaehollandiae) has reinforced the role the world's second largest extant bird plays in dispersing seeds in the environment as well as indicate they have started ...

Pests are easier to combat in habitats rich in species

17 hours ago

A diverse and species-rich agricultural landscape is also beneficial to farmers. This isn't just because there are plenty of pollinating insects, creepy crawly pest controllers and other useful helpers. Scientists ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

hcuenoud
not rated yet May 25, 2014
Many other factors could be at play such as mosquitoes/insecticides spraying in cities disturbing insect populations and depleting cankerworms predators. Or fewer birds dining on cankerworms, etc...
Any species generally multiplies well, mainly because lack of predators.

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.