Changes in populations of waterbirds on a wetland following water storage

Abstract

Toombullen was an intermittently flooded wetland near the Murrumbidgee River in southern inland New South Wales. In 1980 it was converted to an off-river storage. In the decade following impoundment, waterbirds at Tombullen showed a range of responses to permanent inundation. Abundances of Australia pelican, little pied cormorant, great cormorant, yellow-billed spoonbill, black swan, grey teal, maned duck, great crested grebe, Australasian grebe, freckled duck, Eurasian coot, great egret, little egret and intermediate egret decreased. Numbers of Pacific heron and straw-necked ibis increased, while Australia darter, little black comorant, Pacific black duck, Australian white ibis and royal spoonbill did not show consistent trends in abundance. The death of permanently inundated red gums coincided with cessation of egrets breeding and enhanced breeding of Pacific herons. Permanent impoundment of water in Tombullen disadvantaged most species, did not affect a few, had positive impacts on two species of waterbird and reduced species diversity.