[1][2] The area had previously degraded into a wasteland that included a go-kart track, playing fields, demolition spoil, farm land and a cattleyards.

[6] In 2002 the area of the reserve was extended by 1.8 ha (4.4 acres) through the purchase by the Nature Heritage Fund of land adjoining the banks of the Pauatahanui Stream.

The main wetland species are reeds, rushes, harakeke, raupō, glasswort, sea primrose, New Zealand spinach, half-star, and wild celery.

[1][8] Many different native and exotic birds can be found at the Pāuatahanui Wildlife Reserve, including the bar-tailed godwit, royal spoonbill, caspian tern, paradise duck, pied stilt, sacred kingfisher, white-faced heron, Australasian shoveler, pūkeko and black shag.

This stream provides habitat for native and threatened fish species including inanga, longfin eel, giant kōkopu, and redfin bully.

The results of the study emphasise the critical importance of strategies to reduce the amount of fine sediments from catchment areas that reach estuaries.

[16] In 2011, the wildlife reserve was being polluted by sewage runoff from septic tanks in adjoining properties that were not connected to a trunk sewer.