Nav: Home

Garlic mustard populations likely to decline

June 14, 2016

URBANA, Ill. - Invasive plants are often characterized as highly aggressive, possessing the power to alter and even irreversibly change the ecosystems they invade. But a recent University of Illinois study shows that one such invader, garlic mustard (Alliaria petiolata), actually becomes less aggressive over time.

"One of the things we've seen over the last 20 to 30 years is that garlic mustard becomes less of an issue, and actually balances out over time," says University of Illinois and USDA Agricultural Research Service ecologist Adam Davis.

When garlic mustard arrives in a new location, it releases a chemical known as sinigrin into the soil. Sinigrin is toxic to other plants and to the mycorrhizal fungi community, which other plants depend on to facilitate uptake of certain nutrients and water. Without their fungal partners, and through direct competition with growing garlic mustard populations for physical space, native plants quickly die out.

But when a garlic mustard population has been around for awhile, it produces less sinigrin.

"There's a fitness cost to producing sinigrin. So, when the native competitors drop out, it makes sense for garlic mustard to slow its production of this chemical," Davis explains.

In demonstrating the relationship between competition, an ecological phenomenon, and sinigrin production, an evolutionary phenomenon, the research team provided the first empirical example of a negative evolutionary feedback on an invasive species. That is, as garlic mustard populations become larger and more dense as a result of their superior competitive advantage, natural selection begins to act against the very mechanism that allowed for their initial success.

"Even though you might expect ecological processes to influence genetic and evolutionary ones, it has been shown very few times. It's an unusual thing to quantify, and, as far as we know, negative feedbacks haven't been demonstrated for other invaders," Davis says.

If garlic mustard becomes less aggressive over time, should landowners just leave it alone? Davis doesn't recommend a completely hands-off approach, but thinks landowners and managers should take a more holistic view of the ecosystems that garlic mustard invades.

"It may be satisfying to pull garlic mustard, but the damage you're doing to the herb layer by trampling it or by hosing it down with a chemical is probably worse than the garlic mustard itself. The main thing that creates space for garlic mustard is repeated disturbance. Landowners should try to minimize those disturbances and promote a healthy forest without micromanaging it," Davis suggests.

It might take decades to see garlic mustard fade out after its initial invasion, but Davis thinks there's reason to believe it will happen. "Ultimately," he says, "our results tell us we should have some faith in the ability of the ecosystem to achieve a new balance."

The article, "Evolutionary feedbacks on the ecology of the invasive plant Alliaria petiolata," is published in Functional Ecology.
-end-


University of Illinois College of Agricultural, Consumer and Environmental Sciences

Related Ecosystems Articles:

Rethinking role of viruses in coral reef ecosystems
Viruses are thought to frequently kill their host bacteria, especially at high microbial density.
Sequestering blue carbon through better management of coastal ecosystems
Focusing on the management of carbon stores within vegetated coastal habitats provides an opportunity to mitigate some aspects of global warming.
Tiny bacterium provides window into whole ecosystems
MIT research on Prochlorococcus, the most abundant life form in the oceans, shows the bacteria's metabolism evolved in a way that may have helped trigger the rise of other organisms, to form a more complex marine ecosystem with overall greater biomass.
Road salt alternatives alter aquatic ecosystems
Organic additives found in road salt alternatives -- such as those used in the commercial products GeoMelt and Magic Salt -- act as a fertilizer to aquatic ecosystems, promoting the growth of algae and organisms that eat algae, according to new research published today in the Journal of Applied Ecology.
Marine ecosystems show resilience to climate disturbance
Climate change is one of the most powerful stressors threatening marine biomes.
Ecosystems in the southeastern US are vulnerable to climate change
At least several southeastern US ecosystems are highly vulnerable to the impacts of present and future climate change, according to two new USGS reports on research conducted by scientists with Interior Department's Southeast Climate Science Center.
Islands and their ecosystems
Juliano Sarmento Cabral comes from a country with a tropical-subtropical climate.
Restoring ecosystems -- how to learn from our mistakes
In a joint North European and North American study led by Swedish researcher Christer Nilsson, a warning is issued of underdocumented results of ecological restorations.
Beach replenishment may have 'far reaching' impacts on ecosystems
UC San Diego biologists who examined the biological impact of replenishing eroded beaches with offshore sand found that such beach replenishment efforts could have long-term negative impacts on coastal ecosystems.
Overfishing increases fluctuations in aquatic ecosystems
Overfishing reduces fish populations and promotes smaller sizes in fish.

Related Ecosystems Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Climate Crisis
There's no greater threat to humanity than climate change. What can we do to stop the worst consequences? This hour, TED speakers explore how we can save our planet and whether we can do it in time. Guests include climate activist Greta Thunberg, chemical engineer Jennifer Wilcox, research scientist Sean Davis, food innovator Bruce Friedrich, and psychologist Per Espen Stoknes.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...