We often use the term invasive to describe any critter or plant that is causing a disturbance, but there are quite a few specific characteristics of a species that deem it truly invasive. For example, all people can vouch for the fact that mosquitos are frustrating and can cause harm to humans, but many species of mosquitos are native to the area, which makes them not invasive! For a species to be labeled as invasive, it must have some or most of the following characteristics:
Non-native to the Area it is Invasive to
This means that in order for a species to even be considered as invasive, it needs to be occupying a habitat or area that it is not native to. Many invasive species get to their new locales via human introduction and in most cases it’s a complete accident. Because of human beings’ ability to travel with ease from region to region around the world, the massive trade industry between countries, the manufacturing of goods worldwide and even the international pet trade, animals are constantly being introduced to areas where they are not native to. Some animals will be unable to transition to new habitats, some will survive but not cause much disturbance and others will completely take over.
Harmful to the Economy, Environment or Human Health
An example of an invasive species that has caused economical damage to an area is the invasive Asian Carp within the Mississippi river. Four species of carp have taken over the river after being introduce from Asia. They are the Grass Carp, Black Carp, Bighead Carp and Silver Carp. Within the Mississippi river system, aside from costing money to manage, they have negatively impacted the biodiversity of the area, which has also negatively impacted the fishing industries. For 15 years, scientists, fishermen and community members have been trying to manage these aquatic pests spending a grand total of 1.5 billion dollars in an effort to keep them out of the Great Lakes, where their impact on the fishing industry could be irreversible. As of now, they are mostly managed by electric “herding”, which is when boats use sound waves and electric currents to drive the fish into 1,000 foot long nets. Female carp are able to lay up to 5 million eggs at a time, making it near impossible to manage the populations without continuously spending on resources and manpower. One idea for the future that may allow for some kind of long-term management, at least to keep the fish out the Great Lakes, is to create an underwater dam that blocks fish using the same electric currents and sound waves used to control them now by boats!
Ability to Reproduce Rapidly/Grow Quickly
One of the characteristics that makes invasive species so difficult to manage, as mentioned with the invasive carp species of the Mississippi River, is their ability to reproduce rapidly and grow quickly. What this means is that many invasive species have a very short time between when they are born and when they are mature enough to reproduce themselves. Not only do they reach maturity quickly, but they also tend to have a large number of offspring. Individuals reaching maturity quickly and the ability to produce huge numbers of offspring results in the perfect storm for extreme population growth.
Wide Range of Adaptations
How can you help?
Many invasive species get from place to place by hitch-hiking with humans. This can be from latching onto trade-ships, or even attaching to a camper on a weekend in nature.
Some ways that you can help to prevent the spread of invasive species are by planting native plants in your yard or garden, cleaning off boots and clothes after a hike in an area with known invasives, rinsing off your boat after each use to get rid of aquatic hitchhikers, finding the appropriate way to manage household pets, reporting sightings of invasive species, volunteering with a removal project, and by researching invasive species near you!
NRT's dedicated staff are responsible for the content of the NatureTalk blog. Questions? For more information on any blog post, please contact us at any time.