Étude de cas sur les impacts
Hybridation: Mallards hybridize with Australia native Pacific black duck (Anas superciliosa). In locations such as Lord Howe Island no pure populations of A. superciliosa remain (Tracey et al., 2008).
Compétition: The mallard is believed to compete with native waterfowl in India (Williams, undated).
Hybridation: In New Zealand, Anas platyrhynchosis is deemed to have caused severe declines in populations of the native Pacific grey duck (see Anas superciliosa in IUCN Red List of Threatened Species) through genetic introgression. As agricultural regions are now largely dominated by the introduced mallard A. superciliosa has become increasingly restricted to undeveloped areas (Rhymer et al., 1994, 2004; BirdLife International 2004).
Hybridation: Anas platyrhynchos hybridise with native Yellow-billed duck (A. undulata) in South Africa establishing a potential threat (AEWA, 2003).
Western Cape (South Africa)
Hybridation: Anas platyrhynchos hybridise with native Yellow-billed duck (A. undulata) in West Cape, South Africa where it is considered a major problem (AEWA, 2003).
United States (USA)
Hybridation: In North America, Anas platyrhynchos hybridizes with mottled ducks (Anas fulvigula), black ducks (Anas rubripes), and Pacific black ducks (Anas superciliosa) which have experienced decline believed to be a result of this hybridization. As a consequence of hybridisation with mottled ducks, releases of mallards have been prohibited in Florida (Kulikova, 2005; Muñoz-Fuentes, 2007; Rhymer et al., 1994; Snyder, 1993).
Hawaii (United States (USA))
Hybridation: Anas platyrhynchos threatens the endemic 'Endangered (EN)' Hawaiian Duck (see Anas wyvilliana in IUCN Red List of Threatened Species). Hybridization between the mallard and Hawaiian duck have greatly depleted pure stocks of Hawaiian ducks to the point they face extinction if it continues