What is an Invasive Species?

The occurrence of non-native species in the United States is not a new phenomenon. It has been ongoing for decades, including both intentional and unintentional introductions. Many introductions have proven to have beneficial economic and social effects, for example beef cattle, poultry, agricultural products, to name a few. However, a certain percentage of non-native species, introduced either intentionally or unintentionally, have harmful or damaging effects on the ecosystem that is invaded, causing extensive changes to the native vegetation (plants), wildlife, and the habitat. These changes degrade the overall quality of the environment where they occur, and often result in negative economic and social impacts. Such non-native species are classified as invasive.

We cannot, however, afford to focus only on those non-native species that are known to be invasive. That approach will only lead to more and more invasions of harmful organisms. Some non-native species manifest negative impacts in a very short time following their introduction, while others may exist relatively unknown for a long time before beginning to spread successfully. It is important that any approach to managing the invasive species problem include assessing the risk that species not yet introduced and species already introduced but seemingly inactive or not visibly harmful will become invasive.

Characteristics of Invasive Species, Habitats Susceptible to Invasion, and Generalized Rules Governing Invasions

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Gulf States Marine Fisheries Commission.*

* Current site content modified from original content developed by the University of Southern Mississippi/College of Marine Sciences/Gulf Coast Research Laboratory through a grant administered by the Gulf of Mexico Program.