Invasive Species

An invasive species is a species that is not native to a specific location (an introduced species) that has a tendency to spread to a degree believed to cause damage to the environment, human economy or human health. These invasive, sometimes called alien, species may only directly impact one or two other species, but over time this can alter entire ecosystems. The invasive species that have been recorded inhabiting the River Thame catchment area are listed below.

Click on any of the invasive species below to find out more information.

If you would like any more information on any of these species, please visit the GB non-native species website at

With thanks to GBNNSS & Inger Jennings (Environment Agency) for use of the photographs in the article.