此物种详细信息 Tristan da Cunha Is. (sub-Antarctic)
来源： Island Conservation and Ecology Group, 2004
The ship rat (Rattus rattus) was probably introduced to Tristan through a shipwreck, it has self-dispersed over the entire island from lowlands through to the high altitude areas. Rats are generally more abundant on Tristan in lowland areas, but signs have been found everywhere from sea level to the Peak. On the Base, rats are most abundant in Phylica arborea habitat. No information on population trends is available, but rats appear to have spread through all available habitats.
A feasibility study for eradication of rats from Tristan da Cunha has been prepared, along with a draft operational plan. If attempted, a rat eradication from Tristan would be expected to be challenging due to the presence of an established human population, along with the presence of livestock on the island. However, the longer that rats remain on Tristan, the greater the risk that they will be inadvertently introduced to the currently rat-free islands of Nightingale and Inaccessible with devastating effects.
Tristan da Cunha is the largest island (c.9,387 ha) in a remote island archipelago lying approximately 3,000 km from South Africa. The Tristan archipelago holds the highest number of endemic and globally threatened terrestrial species of any of the UK Overseas Territories. Tristan, along with the other major islands of the group, has been recognised as an Important Bird Area (IBA) by Birdlife International.
Tristan has a resident population of approximately 285-300 people, all based at Edinburgh or ‘the Settlement’. The island rises to 2,048 m (6,760 ft), and encircling the island from near sea level to 600 m are the cliffs which separate the coastal plains and shoreline from the upper portion of the island: ‘the Base’. There are four small coastal plains below the Base cliffs: Settlement Plain, Cave Point, Stony Beach, and Sandy Point.
Bird species breeding on Tristan include: the 'Endangered' sooty albatross (Phoebetria fusca) and Atlantic yellow-nosed albatross (Thalassarche chlororhynchos); the 'Vulnerable' Northern rockhopper penguin (Eudyptes chrysocome moseleyi), Atlantic petrel (Pterodroma incerta) and Gough moorhen (Gallinula comeri); the 'Near threatened' grey petrel (Procellaria cinerea), sooty shearwater (Puffinus griseus), and Tristan thrush (Nesocichla eremita); and broad-billed prion (Pachyptila vittata), Kerguelen petrel (Lugensa brevirostris),
soft-plumaged petrel (Pterodroma mollis), great-winged petrel (Pterodroma macroptera),
great shearwater (Puffinus gravis), Antarctic tern (Sterna vittata), brown noddy (Anous stolidus)
and Subantarctic skua (Catharacta antarctica).
传播疾病: Ship rats pose an as yet un-quantified risk to human health on the island. At least one person is known to have required antibiotic treatment after a rat bite. People on Tristan are in general concerned about the potential for rats to spread disease on the island.
威胁濒危物种: The endemic Tristan thrush (see Nesocichla eremita in IUCN Red List of Threatened Species) (locally known as the ‘starchy’) is almost certainly affected by rat predation. Thrush nests tend to be constructed on or near the ground, making them highly vulnerable to rat predation. The relative scarcity of thrushes on Tristan in comparison to their abundance on the nearby rodent-free islands of Nightingale and Inaccessible is strongly suggestive of the effects of rodent predation. If rodents were inadvertently introduced to these islands, the impacts would potentially be devastating, especially for birds such as the flightless Inaccessible rail.
Rats are probably affecting the breeding success of the 'Vulnerable' Atlantic petrel (see Pterodroma incerta in IUCN Red List of Threatened Species) (IUCN, 2007). It is likely that the Tristan moorhen (see Gallinula nesiotis in IUCN Red List of Threatened Species) was extirpated from Tristan as a result of predation by black rat, combined with feral cat predation, habitat loss and hunting by islanders. The successful establishment of the 'Vulnerable' Gough moorhen (see Gallinula comeri in IUCN Red List of Threatened Species) on Tristan suggests that it is able to cope with current levels of rat predation (IUCN, 2007).
经济 /民生: The growing of potatoes as a staple food crop is a fundamental aspect of Tristan life. Rats cause major problems for stored potatoes. Rats often damage seed potato stores, and the seed potatoes required for each year’s crop have to be held in rodent-proof wire cages. Similarly, potatoes for consumption are usually stored in sheds within the settlement, and are prone to rat feeding damage and to contamination through soiling from rat urine and faeces. Rats also feed on other island crops (e.g. pumpkins). The school and supermarket have had ongoing problems with rodent infestation, requiring closures for poisoning.
降低本地生物多样性: It appears that populations of small seabirds on Tristan have been dramatically reduced through the impacts of rats over the past 120 years. Firm evidence of rat predation on broad-billed prion (see Pachyptila vittata in IUCN red List of Threatened Species) eggs has been found on the island. It is likely that if rats remain on Tristan, the populations of seabirds will continue to decline. This will be a major biodiversity loss, as Tristan itself is the only known breeding site within the Tristan archipelago for at least four species of seabirds.
最后修改 ： 20/09/2007 9:09:20 a.m.