Details of this species in Falkland Islands (Malvinas) (sub-Antarctic)
Status: Alien Invasiveness: Invasive Occurrence: Reported Source: Brown et al., 2001a in Varnham, 2006; Brown et al., 2001b in Varnham, 2006
Arrival Date: 1725-1833/ late 18th century Introduction: Unintentional (accidentally)
Species Notes for this Location: Rattus norvegicus commonly known as brown or Norway rat are recorded on all main islands, and also on many of the c. 778 offshore islands. Work is continuing to ascertain which islands are infested. Brown rats are common and widespread in settlements and camps (there is no reliable evidence on distribution of separate species). Brown rats are found in 47, 10km squares. Populations are stable but there are concerns of increase. Brown rats swim from mainland to islands and also between islands. Historically they also are likely to have been moved around by boat traffic. Ther are risks of rats getting to islands on larger boats (Brown et al., 2001a in Varnham, 2006).
Management Notes for this Location: Eradication projects have been carried out on 9 islands in 2001. Some educational work has been carried out and data collected on bird numbers on these islands (Brown et al., 2001a in Varnham, 2006). A guiding document has been produced to assist with prioritising islands for rat eradication (Brown et al., 2001b in Varnham, 2006). Selected control programme are ongoing (Falklands Conservation).Further rat eradications, are planned including eradication from high-priority 305ha North-East Island (Brown et al., 2001a in Varnham, 2006; Brown et al., 2001b in Varnham, 2006). Further selective control is recommended, also eradication from all sensitive sites (mainly islands).
Impacts: Habitat alteration: Brown rats may have some impacts on vegetation. Reduction in native biodiversity: The presence of rats on islands is negatively correlated with the presence of seven species of native passerines (Varnham, 2006). Threat to endangered species: Brown rats are likely to have destroyed whole poulations of 'Vulnerable (VU)' Cobb's wren (see Troglodytes cobbi in IUCN Red List of Threatened Species) and many other land and seabirds, especially burrowing petrels (BirdLife International 2006). Breeding of the Tussock bird (Cinclodes antarcticus antarcticus) has become restricted to cat- and rat-free islands. Reduction of small petrels including Antarctic prion (Pachyptila desolata) has occurred on rat-inhabited islands (In Atkinson, 1985 in Varnham, 2006).