Definitions Pertaining to Biological Invasions

Nonindigenous species - species that, through human influence, occurs outside of its native range.

Synonyms: non-native species, alien species, and exotic species


Invasive Species - species that have spread beyond the location of their initial establishment, and have become locally abundant. This species causes, or is likely to cause, net harm to the economy, the environment, or human health.

Note: Harm is a function of human values and differs among regions and may also change temporally.


Current Status of Invasive Species in Texas

To date, more than 800 aquatic and terrestrial species have invaded Texas, and experts predict the trend will continue to increase. Existing impacts in Texas are in excess of one billion dollars per year. The following realities will only further contribute to Texas' increased exposure and risk: expansion of the Panama Canal resulting in increased usage of Texas ports; increased risk from Mexico as evidenced by USDA's Animal and Plant Health Inspection Service (APHIS) decision to increase Mexico's alert level to high, and USDA's potential plans to close its Weslaco, Texas Agriculture Research Service Laboratory, a key facility that has been helping to respond to invasive species.