Effects of Eliminationof Ali SiahIslandon Breeding and Wintering Populationof Waterbirdsin Karun River

There are 28 islands in Karun River in Ahwaz City that one of them is Ali Siah. The islandis covered by Phragmites australis, Populus euphratica, Prosopis sp. and Tamarix sp. This study assessed the species composition, relative abundance and species diversity of waterbirds found on and around this island. A total of twenty one species, seven families and two orders were identified. From each twenty one species, nine species belonged to waders and wading birds and 12 species belonged to waterbirds. Five species of Ardeidae, namely Little Egret Egretta garzetta, Cattle Egret Bubulcus ibis, Black-crowned Night Heron Nycticorax nycticorax, Squacco Heron Ardeola ralloides and Grey Heron Ardea cinerea were breeders. Nests of five mentioned species counted in nine years 2002–2015 on this island. Breeding population reduced from 736 in 2002 to 312 pairs in 2014 and zero in 2015. The reduction was 57.61% in 2014 and 100% in 2015. The Little Egret was dominant in winter and in breeding colony (maximum 365 individuals in winter 2003 and maximum 245 pairs in 2007 and 2010 respectively). Wintering population reduced from 946 to 32 individuals. The reduction was 96.6% in 2014 and 100% in 2015. The reason of absence of breeding and wintering population of birds in 2015 was elimination of Ali Siah Island.