Impact to Ecosystems
Food Webs
Non-Native:
This is a food web of garlic mustard's non-native or invaded habitat. Notice how garlic mustard has no predators, therefore enabling it to have a much larger population.
Native:
This is a food web of garlic mustard's natural habitat in Europe. In this ecosystem, garlic mustard has predators, or organisms that eat it which keep its population in check. The animals that eat garlic mustard are mostly insects.
Invasions such as the one pictured on the left can completely destroy the undergrowth of an ecosystem.
On the right it can be seen that the removal of garlic mustard from an ecosystem is imperative because of the amount of damage it causes to all of the undergrowth.
On the right it can be seen that the removal of garlic mustard from an ecosystem is imperative because of the amount of damage it causes to all of the undergrowth.
Displacement of Other Species
Garlic mustard displaces many other native plants in the areas that it invades. Since it grows mostly when the other plants are dormant, or not growing, it can outgrow them and create too much shade over them. That makes it take up most of the undergrowth. It also releases a chemical that prevents most of the other plants seeds to germinate, preventing their spread. Trees in the areas it invades have a tough time growing because of the chemical and also because when they are seedlings, the garlic mustard plants create too much shade for the sapling to grow. The mosses and grasses in its natural habitats prevent that chemical from taking effect, but with the absence of those in North America, garlic mustard's spread grows exponentially.
In Europe and Asia where it is naturally found, a wide variety of insects call garlic mustard food. Having all of those bugs eat the garlic mustard keeps the population in check, and does not allow any outbursts of the plant in unwanted areas. However, in the united states the vast majority of those insect species are not present, and so garlic mustard is able to thrive anywhere it colonizes. With very few predators, garlic mustard is able to out compete other plants that are native to the area, causing a collapse in the ecosystem. This collapse in the ecosystem allows garlic mustard to thrive even more, sending the entire area into a downward spiral.
Many factors contribute to garlic mustard's rapid spread in North America. Most ecosystems have a very difficult time dealing with garlic mustard because of its harmful effects.
In Europe and Asia where it is naturally found, a wide variety of insects call garlic mustard food. Having all of those bugs eat the garlic mustard keeps the population in check, and does not allow any outbursts of the plant in unwanted areas. However, in the united states the vast majority of those insect species are not present, and so garlic mustard is able to thrive anywhere it colonizes. With very few predators, garlic mustard is able to out compete other plants that are native to the area, causing a collapse in the ecosystem. This collapse in the ecosystem allows garlic mustard to thrive even more, sending the entire area into a downward spiral.
Many factors contribute to garlic mustard's rapid spread in North America. Most ecosystems have a very difficult time dealing with garlic mustard because of its harmful effects.
Sources
Information: Wikipedia; http://en.wikipedia.org/wiki/Alliaria_petiolata, Invasive.org; http://www.invasive.org/browse/subinfo.cfm?sub=3005,
Pictures: Wilderness waypoint; http://wildernesswaypoint.com/wild-edibles-recipes-garlic-mustard-pesto/, Ohio geology and biodiversity; http://ohiogeologyandbiodiversity.blogspot.com/2010/04/invasive-garlic-mustard.html, Food webs created using Microsoft PowerPoint.
Pictures: Wilderness waypoint; http://wildernesswaypoint.com/wild-edibles-recipes-garlic-mustard-pesto/, Ohio geology and biodiversity; http://ohiogeologyandbiodiversity.blogspot.com/2010/04/invasive-garlic-mustard.html, Food webs created using Microsoft PowerPoint.