We evaluated niche overlap and habitat use among duck broods on Turnbull National Wildlife Refuge (Turnbull NWR). During summer of 1983 and 1984, 485 brood observations were recorded in 46 days. Data were gathered on 320 feeding broods of 9 species along 12 niche dimensions. Mean niche overlap values ranged from 0.62 to 0.94 for 36 possible species pairs. The greatest niche separation occurred on hatching date and feeding depth dimensions. Gadwall (Anas strepera) and teal (A. discors and A. cyanoptera) broods were ecologically very similar. Both had sharp mid-season hatching peaks and fed over dense beds of submerged macrophytes. Five species of diving duck broods tended to feed in deeper water and over areas with sparse submerged macrophytes. Among diving ducks, bufflehead (Bucephala albeola) broods were ecologically distinct, feeding over sparse vegetation often far from land. Mallard (A. platyrhynchos) broods were ecologically isolated from other dabbling ducks. They fed in shallow water within stands of emergent vegetation. The niche for ring-necked duck (Aythya collaris) broods was most similar to dabbling ducks, but also showed similarities with other divers.
引证/输出
预览资料
文章 : 英语