The Snares Islands

Snares Islandsritters

Te Papa's crew recently paid a visit to the Snares Islands Nature Reserve, 105 km SW of Stewart Island, where they carried out a number of sea bird and phytosanitary researches. Here Colin Miskelly (Curator Terrestrial Vertebrates) is describing some of the smaller residents of the Snares Islands. Snares Island Expedition to learn more about our research in the Snares Islands.

Snares Islands is one of the least changed places in New Zealand. There are not only few indications of man but also no imported types of mammals have ever settled on the islands. Missing in the Snares, the islands have preserved a remarkable wildlife of large invertebrate animals.

Nudibranchs are found all over New Zealand, but are much more abundant on islands without gnawers. Pyheaneitea hauttoni is found endemically in the Snares Islands (which means that it is only found there, of course) and is often seen on Olearia logs on humid night. On the Snares Islands, one of our missions was to find onchid nudibranchs along the rock.

The Oncidiidae are related to worms and gastropods, but a few of them have come back ashore. We do not know how many kinds are found on the islands just outside New Zealand, and we were asked to gather samples for a genetics research group. In spite of intensive search on the principal isle we found only on the isle Toru in the western chain, 5 km southwest of the principal isle.

Snare Island's peaty ground is fertilized by the feces of billions of sea birds. Maybe this is why there are plenty of worms, and some are very large. Haplocystal diplotrema becomes 30 cm long. Both of the two types of veta on the Snares Islands are atypical.

Soil moisture Hemiandrus subantarcticus belongs to a common New Zealand genera, but the bouncing Neta Insulanoplectron is located in its own genera, and so both the speca and the genera on the Snares Islands are local. On the Snares Islands the biggest bug is the runner bug (carabid) Mecodema alterans mershon.

Whereas this variety is native to the Snares Islands, the nomination is found in Otago and the Chatham Islands. Prodontria lonitarsis larvae of the scarab (beetle) are found in the Snares Islands, and the adult airborne are sometimes seen on grass at noon. The weevil is the most species-rich organism group on earth.

The same applies to the Snares Islands with ten different types, the four biggest of which are shown here. Each of the two biggest weevils on the Snares Islands has a captivating preservation story. They are both air-impaired and have lifecycles that are entirely dependant on a unique type of plants whose nymphs feed on the root, and the adult ones that appear on the foliage and stalks at nocturnal.

Knubbelkäfer (Hadramphus stilbocarpae) on the Snares Islands only lives on the large-leaved Pinui (Stilbocarpa robusta). It used to be found on the Big Cape Island (Taukihepa) off the southwest shore of Stewart Island, but was extinct during the invasion of shipping rat in the early 60s. There, and on Bird Island and Solander Island (Foveaux Strait), Knubbelkäfer eat (or feed) the related Stilbocarpa Lyalliis.

In Fiordland (Breaksea Island, Resolution Island and Puysegur Point), however, there have recently been found population feeding on the carrot-like anisotomes lyalli. However, the carrot-like anisotomes are still in existence. No one knows why the Knubbel beetles on the Snares Islands do not also devour the close related anisotomes attifolia. Lyperobius sesidiotes is the most rare proboscidean beetle on the Snares Islands. It lives only on the native plant of the species anisotomous species ancifolia.

It is very seldom on the islands and only occurs in two or three places on the isle. Complicating the situation is that the Lyperobius proboscis beetle was never found on the principal islet ( "North-East Island") and is regarded as native to the much smaller Broughton Isle, where it was found in an anisotome field about the scale of a small room.

Recent studies by the Department of Conservation for Uncommon Crops on Broughton Iceland have found no anisotomes, and it is possible that this large air-poor proboscis beetle, which is completely dependant on a unique type of herbicide vector, has eroded to die. A NIWA research crew went to Broughton Iceland on March 4, 2014 to enumerate Bullers molly mawks and found that there are at least one spot of dispersed anisotomes on the islands, and there is still room for improvement for the proboscine beetle.

Thanks to the Department of Conservation for allowing me to see the Snares Islands Nature Reserve, Pete McClelland for information on blood stock and Paul Sagar for the Broughton Island up-date.