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2784Fwd: RE: Bugs on the Brink - and slimy stuff

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  • Bob Conrich
    Jun 7, 2014
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      Many thanks to Vince Thompson of the St. Helena Independent for the report below.


      Robert S. Conrich, ACIArb
      Box 666
      Anguilla bob@...
      British West Indies Tel: 1 264 497 2505

      In response to Bob’s recent email, below are the text extracts referring to Tristan from the
      RSPB/FCO report on wildlife in the OTs.

      There are graphs, photos and diagrams in the report which are not included here and can be found at

      *Tristan da Cunha*

      Total species recorded 1,921
      Native species 1,641
      Known endemic species 183
      Endemic species assessed for the IUCN Red List 25
      Endemic Globally Threatened species 12
      Known non-native species 280


      The Overseas Territory of Tristan da Cunha consists of three main islands in the cool temperate
      South Atlantic: Tristan da Cunha (96 km2), Inaccessible (16 km2) and Nightingale (4 km2). Gough
      Island, with an area of 65 km2, is 350 km to the southeast. All are volcanic islands and the volcano
      on Tristan da Cunha (the only inhabited island with a population of 250–30046) has been active as
      recently as the 1960s. There is a permanently manned South African meteorological station on Gough

      The uninhabited islands of Nightingale, Inaccessible and Gough, are home to endemic landbirds and
      are recognised as some of the most important islands for seabirds in the world, being the only
      breeding location for some species47, 48. As a result, there has been a considerable amount of
      research on the birds of these islands (particularly on Gough). More recently attention has turned
      to the impact alien invasive mice have on bird populations, and the feasibility of eradicating these


      Results are summarised in the table above and in figure 19. Our knowledge is comparatively good
      compared to other island OTs, particularly lower plants and the breadth of marine invertebrate
      groups documented. To date 155 (10%) of the 1,641 native species recorded in the Tristan da Cunha
      Islands have been assessed against IUCN Red List criteria. Of the 155 native species assessed, 32
      are Globally Threatened with a further 10 Near Threatened and 17 Data Deficient. The remaining 96
      assessed native species are Least Concern. Of the 183 known endemic species, 25 have been IUCN
      assessed. Twelve are Globally Threatened (7 VU, 2 EN, 3 CR), one is NT, 5 are DD and the remaining
      are LC.


      Although coverage of most taxonomic groups is good, the most recent (and often only) records for
      many species on Tristan, Nightingale and Inaccessible date back to the Norwegian expedition of
      1937–38. The taxonomic status of some species is likely to need revising, and it is unlikely that
      this single expedition was exhaustive in its findings (particularly for groups such as fungi). There
      is much more recent and detailed data from Gough Island; collected by the Gough Island Scientific
      Survey (1955–56), Gough Island Terrestrial Invertebrate Survey and continued research on the island.

      As for most of the island OTs, our knowledge of the marine environment around the Tristan islands is
      weaker than for terrestrial environments. We have good knowledge of the presence of invasive
      species, particularly on Gough Island. We know that some 50 Cuthbert, R., and Hilton, G. (2004)
      Introduced house mice Mus musculus: a significant predator of threatened and endemic birds on Gough
      Island, South Atlantic Ocean? Biological Conservation, 117(5): 483–489 invasive species are
      negatively affecting the seabirds and vegetation; however, we have a limited understanding of the
      threat invasive species pose to the endemic invertebrate fauna. Limited data does suggest that
      populations of introduced mice affect the distribution of the endemic flightless moths on Gough.
      Flightless moths have become much rarer on islands with introduced mice; Dimorphinoctua goughensis
      (endemic to Gough Island) is found predominately above 300 metres, possibly because mice are less
      abundant at higher elevations50.

      No information is available on the distribution or abundance of endemic invertebrates on any of the
      islands except Gough.

      _Areas of outstanding universal value_

      The OTs include areas that are regarded as being of outstanding universal value to humanity,
      including two natural World Heritage Sites. The islands of Gough and Inaccessible are a prime
      example of one of the least disrupted island and marine ecosystems in the cool temperate zone. They
      contain one of the world’s largest seabird colonies and are home to a number of endemic species
      including the Critically Endangered Gough bunting, Rowettia goughensis. UNESCO designated Gough
      Island as a World Heritage Site in 1995 (extended to include Inaccessible Island in 2004). The Site
      has globally important biodiversity and is an area of exceptional natural beauty and aesthetic
      importance. Given their global significance, it is particularly important that conservation efforts
      protect the values of the OT’s World Heritage Sites: at Gough and Inaccessible, and also at
      Henderson Island in the Pitcairn Islands.