Elaborate how invasion by an alien species reduces the species diversity of an area.

Explanation

When alien species are introduced unintentionally or deliberately in a habitat, some of them can cause decline or extinction of indigenous species, e.g., extensive enviromental damage caused and threat posed to our native species by invasive weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eichhornia). Another example of exotic species invasion is Nile perch, a large predator fish.