Details of this species in Sth. Georgia and Sth. Sandwich Iss (sub-Antarctic)
Source: South Georgia Heritage Trust (SGHT), 2011
Arrival Date: c. 1790s / 1800
Introduction: Unintentional (accidentally)
Species Notes for this Location:
The Norway rat was introduced by whalers and sealers to South Geogia after 1775 when the remote island began to be visited. The spread of rats on South Georgia has only been limited by geography - the sea and large areas of permenent ice. With global warming and the retreat of glaciers, areas of the island that were once free of rats have been invaded by this predator and there is danger of increased invasion. There are concerns that islands that are rat free could be invaded; rats have been recorded on Saddle Island that was once rat free.
Predation: Rattus norvegicus take eggs and young of most burrow-nesting small petrels, and also eat penguin chicks (McIntosh and Walton, 2000 in Varnham, 2006). Other sources suggest they are only likely to predate weak or dead penguin chicks (Poncet, 2003 in Varnham, 2006).
Reduction in native biodiversity: Rattus norvegicus are known to eat native plants (esp. Paradiochloa flabellata, a tussock grass), as well as invertebrates and carrion (Leader-Williams, 1985 in Varnham, 2006).
Threat to endangered species: Breeding of the 'Near Threatened (NT) Antarctic pipits (see Anthus antarcticus in IUCN Red List of Threatened Species) and South Georgia pintails (Anas georgica georgica) has reportedly become restricted to rat-free habitats (in 8). However, other more recent sources say that although rats may have reduced pintail numbers and affected breeding success they have not eliminated them, and pintails are found all over South Georgia (Poncet, 2003 in Varnham, 2006).
Last Modified: 17/06/2008 9:57:30 a.m.