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Kermadec Islands

Located between latitudes 29° -32° south and longitudes 177° and 179° west, in the South Pacific Ocean, 1000km northeast of New Zealand

Area:

The islands can be conveniently divided into the southern and northern Kermadecs. Of the northern Kermadecs, Raoul Island 2938ha is the largest island in the group.

The southern Kermadecs include Macauley Island (306ha), and its companion, Haszard Islet (6ha), which lie 108km SSE of Raoul Island. Curtis (52ha) and the adjacent Cheeseman Island (7.4ha), and L’Esperance Rock (4.8ha), lie 35km and 98km respectively, southwest of Macauley Island.

Maximum Altitude:

516m

Physical Features:

Blue Lake ©

The Kermadec group is formed from the summits of volcanic cones which rise from the Keramadec sub-oceanic trench. These cones have developed from submarine vents as a result of tectonic activity associated with the seduction of the Pacific plate under the Indian-Australian plate. Volcanic activity still occurs on Raoul and Curtis Islands and the area is one of the most active earthquake zones in New Zealand. Because the island are of geologically recent origin, and are not situated on the continental shelf, they have never been physically connected to the New Zealand mainland.

Flora and Vegetation:

Denham Swamp ©

The indigenous vegetation of the Kermadecs Islands reflects processes of adaptive evolution arising from isolation, periodic volcanic activity, and human intervention and settlement. These have combined to produce distinctive ecological communities. Of the one hundred and thirteen plants considered to be indigenous to the Kermadecs, twenty two are regarded as endemic. Despite the distance of the islands from the mainland, the affinities of the flora are overwhelmingly with New Zealand, with over one hundred plants and ferns being common to both areas. However, there are also affinities with the vegetation of Norfolk Island and tropical areas, and a number of genera which are present in coastal areas of New Zealand are absent. The Kermadec Islands, in particular Raoul Island, also contain a considerable number of introduced species.

Raoul is the only island within the Kermadecs with vegetation associations other than purely coastal forest. The dominant canopy species is the Kermadec pohutukawa Metrosideros kermadecensis together with the Kermadec nikau Rhopalostylis baueri var. cheesemanii. In the higher altitude wet forest the understorey is dominated by Ascarina lucida var. lanceolata, while Myrsine kermadecensis predominates in the lower dry forest. Other common species include karaka Corynocarpus laevigatus, wharangi Melicope ternata, kawakawa Macropiper excelsum, mahoe Melicytus ramiflorus and tree ferns Cyathea milnei. The higher, wetter areas of the island have considerable numbers of epiphytes, and the introduced aroid Alocasia brisbanensis dominates much of the herbaceous layers of both dry and wet forests. The removal of goats (by 1984) has resulted in the rapid regeneration of a number of species.

Plants of the coastal forest areas of Raoul and the Herald Islands include Kermadec pohutukawa, Coprosma petiolata, Kermadec ngaio Myoporum kermadecense, parapara (Pisonia brunoniana) and karaka. There are open communities of grasses and herbs on talus areas along the cliffs of Raoul Island, and volcanic activity has resulted in an unusual community of plants associated with high temperatures and other usually unfavourable conditions. The vegetation of the smaller islets is largely restricted to salt resistant species.

Grazing by goats (and possibly 19th Century burning) resulted in the conversion of much of the formerly vegetated plateau area of Macauley Island into a short cropped turf. The removal of these animals (by 1970) has resulted in the rapid spread of Cyperus ustalatus and Solanum americanum. Curtis, Cheeseman, and other outer islands in the southern Kermadecs, are largely dominated by coastal herbs

Raoul Island contains one of the world’s rarest plants: Hebe breviracemosa based on only two small populations. Other threatened plants include Cyathea kermadecensis, Boehmeria australis var. dealbata, Peperomia leptostachya now called Peperomia blanda and Senecio kermacedensis. A form of the native groundsel Senecio lautus var. esperensis is restricted to a small area on L’Esperance Rock.

The relatively fertile volcanic soils and equable climate of the island promote fast plant growth and provide a suitable habitat for a number of adventure tropical weed species. Mysore thorn Caesalpinia decapetala was, until weed control operations were undertaken, smothering large areas of vegetation in Denham Bay. Weed control activities have also concentrated on Brazilian buttercup Senna septemptrionalis which is found on both Raoul and the Meyer Islands. There are a number of other species which pose an actual or potential threat to the indigenous vegetation association. Aroid has taken over many areas of the forest floor on Raoul Island, and is also present on the Meyer Island. However, since the goats were removed, the aroid is declining. Increased canopy cover and regeneration of native forest species have reduced light levels for this light demanding species.

The floristic values of the Kermadecs are of international significance. Their importance arises from the unique assemblage of species of both subtropical and temperate origins, and from the number of endemic taxa which have arisen from adaptive evolution on the island.

As many of the taxa associated with both Norfolk and Raoul Islands are now endangered on Norfolk Island, the Kermadecs assume increasing importance
as a repository for these species.

Bird List:

The Kermadec Islands support a rich mix of tropical and temperate species of birds. They are the only breeding place within the New Zealand region for a number of species of petrels and shearwaters, and for “tropical” species such as the red-tailed tropic bird, the masked booby, several species of noddy and terns, and the grey ternlet. There are also a number of bird species which have recognizably distinct populations in the Kermadecs. The southern Kermadecs contain some of the highest concentrations of breeding seabirds in the world.

Although there have been some exceptions (notably tui and sooty terns), indigenous birdlife has been largely exterminated on Raoul Island. Cats, kiore, Norway rats, and possibly goats, have caused the extinction of Kermadec pigeon (Hemiphaga sp.) and the local extinction of the endemic Kermadec parakeet (Cyanoramphus novaezelandiae cyanurus) and the once huge breeding populations of Kermadec petrel (Pterodroma neglecta) from Raoul.

The adjacent Herald Island lacks mammalian predators and contain twelve species of breeding seabirds and the only remaining population of spotless crake within the Kermadecs). The Meyer Islands are now one of the few remaining strongholds of the Kermadec petrel in the world.

The southern Kermadecs support huge populations of breeding seabirds and contain the worlds largest populations of Kermadec allied shearwaters and black-winged petrels. Macauley Island is the only breeding locality of the endemic white-napped petrel (Pterodroma cervicalis), and two rare storm petrels, the Kermadec storm petrel (Pelagodroma marina albiclunis), and the white-bellied storm petrel (Fregetta grallaria), breed there also, Macauley also has very dense populations of Kermadec parakeet.

Although some species are thriving, the restricted range of Kermadec allied shearwaters and the two species of storm petrels on Macauley Island is probably due to kiore predation. Both of these taxa, and grey ternlets, are currently confined to cliff faces and ledges, whereas on Curtis Island, which does not have kiore, ternlets nest all over the island.

Indigenous Bird Species Breeding or Possibly Breeding in the Kermadec Islands:

• Wedge-tailed shearwater Puffinus p. pacificus
• Kermadec little shearwater P. assimilis kermadecensis
• Kermadec petrel P. neglecta
• Black-winged petrel P. hypoleuca nigripennis
• Kermadec storm petrel Pelagodroma marina albiclunis
• White-napped petrel Pterodroma cervicalis
• White-bellied storm petrel Fregetta g. grallaria
• Red-tailed tropic bird Phaethon rubricauda
• Masked booby Sula dactylatra
• Grey duck Anas superciliosa
• Australasian harrier Circus approximans
• Spotless crake Porzana tabuensis plumbea
• Pukeko Porphuyrio porphyrio
• Sooty tern Sterna fuscata
• White-capped (Black) noddy Anous tenuirostris minutus
• Brown noddy Anous stolidus
• White tern Cygis alba royana
• Grey ternlet Procelsterna cerulea albivitta
• Kermadec parakeet Cyanoramphus novaseelandiae cyanurus
• Kingfisher Halcyon sancta
• Pipit Anthus novaeseelandiae
• Tui Prosthemadera novaezelandiae

Click here for a detailed Bird Checklist

Marine Ecology:

Lion Fish ©

The marine areas surrounding the Kermadecs are the only true example of sub-tropical waters in New Zealand, and are sufficiently far away from the mainland to have escaped heavy commercial fishing. Because of the great depth of water surrounding the islands, the area around the Kermadecs shallower than 200m extends (on average) only approximately 2km from the shore line.

The marine biota has strong tropical elements, and provides a link between the Indo-Pacific province and the New Zealand region. It is so different from the rest of New Zealand as to require separate status at a major biogeographic level.

A total of 145 fish species have been recorded from around the Kermadecs. Six marine species are endemic (4.6%), and a further six are endemic to the Norfolk-Kermadec region. Fifty-four percent of the Kermadec Islands species occur around the mainland or other offshore islands of New Zealand, but only 29% are common there. The Kermadecs fauna has a greater affinity with that of Lord Howe Island (66%). Furthermore, the species which occur in both the Kermadecs and around mainland New Zealand are not generally abundant in both, only 8 (27%). Therefore, the fauna of the Kermadecs differs markedly from that of other parts of New Zealand in both species composition and in those species which are abundant

Marine algae number 165 species, with red algae making up over half of the total species listed. The seaweeds found around the Kermadecs are characteristically of small size, with most plants 15cm in height. Several algal genera show warm water affinities.

The marine communities are important for their special populations (including the endemic giant limpet (Patella kermadecensis), and the spotted black groper (Epinephalus daemelii), interesting absences (many of the tropical herbivorous fish, most of the larger brown algae), populations of species at their geographic limits (corals and crown of thorn starfish). Marine reptiles which only straggle to the mainland, such as seasnakes and green turtles, are present around the islands.

The Kermadecs contain one of the few shallow marine areas between mainland New Zealand and the coral reefs of the tropics. Together with the communities on Lord Howe and Norfolk Islands, which are at similar latitudes, the marine ecosystems are possible unique.

Historical Features:

Fishing Rock ©

Although occupation had ceased when the first Europeans visited the islands in the late 18th Century, archaeological records show that Raoul Island was settled by Polynesian seafarers, probably during the phase of expansion into the south-west Pacific about one thousand years ago. The islands may have also acted as a stopping off point on journeys between the islands to the north and New Zealand. The traditional Maori name of Rangitahua has been ascribed to Raoul Island. This may represent a European interpretation made specifically to account for an early collection of Polynesian adzes found on the island.

The absence of ethnographic records means that our understanding of the prehistory of the Kermadecs is now dependent entirely on the remaining archaeological evidence. Research and artefacts found on Raoul to date indicate that the island was occupied about the mid-14th Century, probably from the Society Islands, although Anderson (1980) has suggested two periods of occupation dating from around the 10th and the 14th Centuries. There is preliminary evidence on Raoul of material sourced from New Zealand.

There is some evidence that Polynesian occupation of Raoul may have ended as a result of volcanic eruption. Elsewhere in the Kermadecs, the presence of kiore (Rattus exulans) and charcoal (dating from the 15th Century: Johnson, pers comm.) point to Polynesian contact with Macauley Island. However, the lack of water on the island would probably have precluded long term settlement.

Polynesian settlement areas on Raoul are known to have included Low Flat and the eastern end of the Terraces, and probably Denham Bay. The inhabitants subsisted on marine mammals, muttonbirds, fishing and gardening. Crops possibly introduced by these early settlers include taro (Colocasia esculenta) and kumara (Ipomea batatas). Other Polynesian introductions included kiore, and probably candle nut tree (Aleurites molucanna) and ti (Cordyline terminalis).

The Kermadecs have had a varied history of European contact since their “rediscovery” by a British convict ship in 1788. During the first half of the 19th Century Raoul was used as a base and provisioning point for ships working the rich whaling grounds of the area. Goats were introduced to Raoul and Macauley Island prior to 1836 to provide food for these activities. Pigs were also introduced to both islands but did not thrive.

Macauley Island appears to have been burnt off during the early 19th Century, possibly in conjunction with these introductions.

From 1837 onwards there were a number of attempts to settle Raoul Island and to establish farms and crops. Although these enterprises met with little success, sheep and cattle and a number of exotic crops and adventive plants were introduced, and areas were cleared for pasture and gardens. Volcanic activity resulted in at least one evacuation from the island, in 1870.

Cats arrived on Raoul Island during the 19th Century and Norway rats (Rattus norvegicus) appear to have been introduced to Raoul from the wreck of the “Columbia River” in 1921, but may have been introduced. In 1908 the first assessment of the natural history of the Kermadecs was made by W.R.B. Oliver. His recommendations included reserve protection for the island he “foretold the damage rats and goats would have on indigenous fauna and flora”.

The Kermadecs were annexed by New Zealand in 1887, and the last settlers left Raoul in 1937 when a Government party arrived to establish the radio and meteorological station on the island.