Invasive Species
Occasionally, humans will (whether intentionally or unintentionally) introduce a species to a habitat that it is not native to. Invasive species adapt quickly and will damage the ecosystem due to outcompeting the native species. Typically, they do not have a predator, which aids in their ability to harm the ecosystem.
Invasive species are often generalists and r-selected, which allows them to adapt easily and reproduce quickly.
Invasive Species Examples
Click Here to Read the Story of the Cane Toad
Cane toads are native to South and Central America. They were introduced to Australia to combat a pest problem with the sugar cane crops. However, the grey-backed cane beetles live near the top of the sugar cane, and the cane toad is not prone to climbing. This resulted in them not helping at all with that problem, but eating various other native species and spreading throughout the country. As they are poisonous, native species could not eat them. Numerous species were negatively impacted due to their introduction.
Click Here to Read About Kudzu
Kudzu is a fast-growing vine from Japan. It was brought to the Southern US for ornamental and erosion-fighting purposes. In Japan, it was kept in check by cold winters, which are not present in the Southern US. This results in it growing out of control (up to 1ft/day). Kudzu climbs over trees and shrubs and kills them via blocking out the sun.
Click Here to Read About Zebra Mussels
Zebra mussels are a mussel native to Eurasia. They came to the Great Lakes region through boats. They are now a massive problem in the lakes. They filter out algae that native species need for food. They attach to and incapacitate native mussels, disrupting food webs. They can also clog water intakes, particularly in power plants, which costs millions of dollars to remove.
What can be done to control invasive species?
There are three main strategies for controlling invasive species.
Legal methods: Laws can be passed to prevent the transport of invasives. For example, firewood cannot be transported across certain borders in order to prevent the spread of the emerald ash borer.
Physical removal: Organisms can be directly hunted or removed. Invasive plants are often cut down, zebra mussels are detached from boats, and invasive pythons in the Florida Everglades are hunted.
Biological control: This is the There Was An Old Lady Who Swallowed A Fly strategy: introduce natural predators to deal with the invasives. Chinese wasps have been introduced to kill emerald ash borers.
It is worth noting that all introduced species are invasive, many have little to no effect on the ecosystem.