page_title: Rangitoto Island
section_title: Biology
hierarchical_section_title: Rangitoto Island / Biology
caption_attribution_description: Orchids growing on Rangitoto Island, New Zealand, near the lava caves. I presume they are some sort of greenhood (Pterostylis).
context_page_description: Rangitoto Island is a volcanic island in the Hauraki Gulf near Auckland, New Zealand. The 5.5 km wide island is a symmetrical shield volcano cone, reaching a height of 260 m. Rangitoto is the youngest and largest of the approximately 50 volcanoes of the Auckland volcanic field, having formed in an eruption about 600 years ago, and covering an area of 2,311 ha. It is separated from the mainland of Auckland's North Shore by the Rangitoto Channel. Since World War II, it has been linked by a causeway to the much older, non-volcanic Motutapu Island.
  Rangitoto is Māori for 'Bloody Sky', with the name coming from the full phrase Ngā Rangi-i-totongia-a Tama-te-kapua. Tama-te-kapua was the captain of the Arawa waka and was badly wounded on the island, after having lost a battle with the Tainui iwi at Islington Bay.
context_section_description: Because there are virtually no streams on the island, plants rely on rainfall for moisture. It has the largest forest of pohutukawa trees in the world, as well as many northern rata trees. In total, more than 200 species of trees and flowers thrive on the island, including several species of orchid, as well as more than 40 types of fern. The vegetation pattern was influenced by the more recent eruptions creating lava flow crevices where pohutukawa trees (Metrosideros ssp) grow.
  The island is considered especially significant because all stages from raw lava fields to scrub establishment and sparse forests are visible. As lava fields contain no soil of the typical kind, windblown matter and slow breaking-down processes of the native flora are still in the process of transforming the island into a more habitable area for most plants (an example of primary succession), which is one of the reasons why the local forests are relatively young and do not yet support a large bird population. However, the kaka, a New Zealand-endemic parrot, is thought to have lived on the island in pre-European times.
  Goats were present on Rangitoto in large numbers in the mid 19th century and survived until the 1880s. Fallow deer were introduced to Motutapu in 1862 and spread to Rangitoto, but disappeared by the 1980s. The brush-tailed rock-wallaby was introduced to Motutapu in 1873, and was common on Rangitoto by 1912, and the brushtail possum was introduced in 1931 and again in 1946. Both were eradicated in a campaign from 1990 to 1996 using 1080 and cyanide poison and dogs. The eradication campaign did not have a significant effect on bird species diversity and abundance, due to the presence of other predators.
  Stoats, rabbits, mice, rats, cats and hedgehogs remained a problem on the island, but the Department of Conservation (DOC) aimed to eradicate them beginning with the poisoning of black rats, brown rats and mice and in August 2011, both Rangitoto and neighbouring Motutapu Islands were officially declared pest-free with both islands now also boasting populations of newly translocated North Island saddlebacks.
  As the area is a DOC-administered reserve (in partnership with the tangata whenua Ngāi Tai and Ngāti Paoa), visitors may not take dogs or other animals onto the islands.
caption: Pterostylis growing on Rangitoto
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