What are invasive species?

Invasive species can be any living organism including plants, animals, insects, or even microbes and fungi. They are considered species that are non-native to a given ecosystem that also cause economic or environmental harm or negatively impact human health. Several common examples of invasive species in Kansas City include bush honeysuckle, several species of carp, the emerald ash borer, and others.

Not all non-native species are invasive. For instance, some food crops like wheat and rice are not native to North America but do not spread easily on their own outside of cultivation. Invasive species can survive well enough on their own without the assistance of people. Humans can spread invasive species accidentally and on purpose. Sometimes they are spread through ballast water, moving firewood, or when pets are released into the wild.  

The greatest concern for scientists regarding invasive species is they can extirpate native species from their habitat and destroy biodiversity. Biodiversity is essential to proper ecosystem health and maintaining healthy food chains. Non-native species do not have “natural” predators and may be able to outcompete native species due to a lack of shared evolutionary history.

Sometimes scientists use other non-native species to help control invasive species – this is called biological control.  Introducing species to fight invasives is very tricky, as sometimes the weaponized species can become invasive themselves. Other methods of control include chemical sprays, trapping, or hunting in order to prevent the spread of invasive species. However, these methods can sometimes harm native species as well.

Invasive species are not just a problem here in the United States. Below are several different examples of species native to the United States that have become invasive in other countries around the world:

Hudson Pear – Australia 

The Hudson Pear is named after a “Mr. Hudson” who first brought his concern about the planting of this species to local Australian authorities.

The Hudson Pear is a native to Mexico that is now a major problem in Northwest Australia. They were originally planted near mining sites in order to deter non-mining individuals from staking claim to precious gems at the sites. The plant is spread by pieces of the stem which can attach really easily to cars and animals. Researchers have considered using a biological control in order to help prevent its spread. Biological controls are when other species are used to help prevent the spread of the unwanted invasive. However, biological controls can often have dire consequences and become invasive species themselves. Read more here about the Opal Hunters fighting the invasive Hudson Pear.  

For more information on the hunting of precious gems like Opals, check out this title:

The rocking book of rocks : an illustrated guide to everything rocks, gems, and minerals / by Amy Ball and Florence Bullough ; illustrated by Anna Alanko. 

Raccoons – Japan 

Raccoons are omnivores which means they eat both meat and plants – perfect for surviving by scrounging around in garbage cans all over the world.

Raccoons are quite a problem now in Japan, due to the popularity of a 70s TV show. The TV show, Rascal the Raccoon, was an anime series based on an American book in which a young boy and his raccoon sidekick go on numerous adventures. The popularity of the show prompted fans to buy their own pet raccoons with several eventually escaping or being released into the wild. These pet populations grew, and today raccoons cause thousands of dollars in damage to wildlife and agriculture across the country.

Read the book that inspired the television series:

Rascal / by Sterling North ; illustrated by John Schoenherr. 

Colorado Potato Beetle – Former Soviet Europe

Colorado potato beetles are pervasive pests of potato leaves.

Native to the Rocky Mountains, it is a striped beetle that feeds on potato crops. Several Soviet Bloc countries claimed that these insects were introduced by the United States during the Cold War as a form of entomological warfare on East Germans. Although these claims proved to be untrue, the French did draft plans for using the beetle against the Germans during World War II. The species likely came to Europe much earlier during World War I and spread with the movement of soldiers across the continent.

Some animals have been used as weapons in warfare in the past; you can read all about it in the following title:

Animal weapons : the evolution of battle / Douglas J. Emlen ; illustrated by David J. Tuss.

Red Eared Slider – India 

Red-eared slider or red-eared terrapin turtle with a red stripe near its ears stands on tree root (Trachemys scripta elegans).

Red Eared Sliders are the world’s most pervasive turtle used in the pet industry. Originally native to the southern United States and Mississippi Delta, their ubiquitous trade has resulted in its invasive status around the world, where turtles have escaped or been set free by their owners. Red eared sliders are the most popular pet turtles in India. Despite having banned the importation of these turtles, the illegal wildlife industry continues to smuggle them in to the country. They are often sold illegally in shops and street strands across the country. India has 29 native freshwater turtles and tortoises currently impacted or threatened by the establishment of red-eared sliders.

Read more about efforts to restore other freshwater habitats around the world: 

Bringing back our freshwater lakes / by Lisa J. Amstutz.