Report to the Republic of Kiribati on Invasive Plant Species on the Islands of Tarawa, Abemama, Butaritari and Maiana
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Report to the Republic of Kiribati on Invasive Plant Species on the Islands of Tarawa, Abemama, Butaritari and Maiana James C. Space and Clyde T. Imada Contribution No. 2003-006 to the Pacific Biological Survey U.S.D.A. Forest Service Bishop Museum Pacific Southwest Research Station Pacific Biological Survey Institute of Pacific Islands Forestry Department of Natural Sciences Honolulu, Hawai‘i, USA 9 September 2004 Report to the Republic of Kiribati on Invasive Plant Species on the Islands of Tarawa, Abemama, Butaritari and Maiana Table of Contents 1. Dangerous species not known to be on the islands of Tarawa, Abemama, Butaritari and Maiana .............................. 2 2. Species that are presently subject to eradication programs........................................................................................... 9 3. Species that are invasive or have the potential to become so on the islands of Tarawa, Abemama, Butaritari and Maiana............................................................................................................................................................................... 9 Invasive species already widespread ............................................................................................................................. 9 Invasive species of limited extent................................................................................................................................ 11 4. Other species that are known or listed as weedy or invasive elsewhere and are common, weedy or cultivated on the islands of Tarawa, Abemama, Butaritari and Maiana...................................................................................................... 13 5. Native species (or Micronesian introductions) exhibiting aggressive behavior ......................................................... 14 General observations and recommendations ................................................................................................................... 15 Species-specific recommendations.................................................................................................................................. 18 Table A. Priority species for exclusion from Kiribati................................................................................................. 18 Table B. Cultivated species of possible threat to Kiribati .......................................................................................... 20 Table C. Species that should be subject to inter-island quarantine............................................................................. 21 Table D. Summary of management recommendations for invasive species present in Kiribati................................. 24 Recommendations by Island............................................................................................................................................ 27 All islands.................................................................................................................................................................... 27 Tarawa......................................................................................................................................................................... 28 North Tarawa............................................................................................................................................................... 29 Abemama..................................................................................................................................................................... 29 Butaritari...................................................................................................................................................................... 30 Maiana......................................................................................................................................................................... 30 Other islands................................................................................................................................................................ 30 Appendix 1. Invasive species ............................................................................................................................................. 31 Table 1. Species that are invasive elsewhere in Pacific and in similar ecosystems but are not known to be present on Tarawa, Abemama, Butaritari or Maiana ........................................................................................................................ 31 Table 2. Species that are subject to eradication programs .............................................................................................. 53 Table 3. Introduced species that are invasive or potentially invasive on Tarawa, Abemama, Butaritari or Maiana ...... 54 Table 4. Other species that are reported as invasive or weedy elsewhere and are common, weedy or cultivated on Tarawa, Abemama, Butaritari or Maiana ........................................................................................................................ 57 Table 5. Native species (or Micronesian introductions) that can exhibit aggressive behavior....................................... 62 Appendix 2. Invasive species present in Fiji, Guam, Hawai‘i, the Marshall Islands, Nauru, Samoa or Tonga but not present in Kiribati................................................................................................................................................................ 63 Appendix 3. Invasive species by location........................................................................................................................... 73 Table 1. Invasive species present on Tarawa................................................................................................................... 73 Table 2. Invasive species present on Abemama .............................................................................................................. 76 Table 3. Invasive species present on Butaritari ............................................................................................................... 77 Table 4. Invasive species present on Maiana................................................................................................................... 79 Table 5. Invasive species present on other Kiribati islands............................................................................................. 80 Appendix 4. Presence of invasive species within Kiribati.................................................................................................. 82 Table 1. Species present elsewhere in Kiribati but not on Tarawa.................................................................................. 82 Table 2. Species present elsewhere in Kiribati but not on Abemama.............................................................................. 83 Table 3. Species present elsewhere in Kiribati but not on Butaritari............................................................................... 85 Table 4. Species present elsewhere in Kiribati but not on Maiana.................................................................................. 87 Appendix 5. Invasive species on North Tarawa ................................................................................................................. 91 Table 1. Invasive species present on North Tarawa ........................................................................................................ 91 Table 2. Species present on South Tarawa but not on North Tarawa.............................................................................. 92 Appendix 6 .......................................................................................................................................................................... 95 Scientific name synonyms............................................................................................................................................... 95 Appendix 7. Background material and references.............................................................................................................. 99 Report to the Republic of Kiribati on Invasive Plant Species on the Islands of Tarawa, Abemama, Butaritari and Maiana James C. Space and Clyde T. Imada1 The Republic of Kiribati requested assistance from the US Department of Agriculture, Forest Service, Institute of Pacific Islands Forestry, to conduct a survey of invasive plant species of environmental concern. Similar surveys have been conducted in American Samoa, the Commonwealth of the Northern Mariana Islands, the Cook Islands, the Federated States of Micronesia, Niue, Palau, Samoa and Tonga. The survey was carried out in August and September 2003. We were requested to survey the islands of Tarawa, Abemama, Beru and Butaritari; however, difficulties with plane connections did not permit us to visit Beru and Maiana was substituted instead. The objectives of the survey were to: (1) identify plant species presently causing problems, particularly in natural and semi-natural ecosystems; (2) identify species that, even though they are not presently a major problem, could spread more widely or are known to be problem species elsewhere; (3) confirm the absence of species that are a problem elsewhere and, if introduced to Kiribati, could be a threat there; and (4) make appropriate recommendations. During