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

Explanation

Some possible explanations are that the alien species may be :
(a) Vigorously growing and compete with the natural plants for minerals , water etc. The less vigorous local species may be eliminated .
(b) Natural pests and predators of the alien species may not be present in the introduced area leading to proliferation in their number .
(c) The introduced species may harm the local species by production of chemical (Amensalism).
(d) The alien spceis by proliferatioon may make conditios unfavourable for the growth of local native plants (e.g., Eicchhornia).