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Great Barrier Island Fauna & Flora

HMS Tortoise plant collection while at Great Barrier Island   The collection during 1842 was of both plants and animals, and may still exist in England. It's well worth some enterprising researcher to hunt it down, for there may be much to be learnt.
 

Great Barrier Island’s living heritage.

 

Finding, identifying, and recording the Barrier's terrestrial and marine native and endemic species of plants and animals has accelerated in the last few years as the realisation dawns on many islanders and other interested people that there is an outstanding wealth of life here. The island's native species encompass flora, birds, reptiles, mammals, fish, and the invertebrates (animals without backbones). No other NZ offshore island has more vascular plant, freshwater fish and lizard species than Great Barrier and its associated islands. The birds and invertebrates are not far behind either. The rapid rate of recent discoveries demonstrates that there are yet more surprises in store within its many diverse ecosystems.  

 

Four out of five species are in the sea around our coast, -  for instance NZ has about 1200 marine fish species, 2000 molluscs, 350 sponges, 400 echinoderms (sea eggs etc), 900 seaweeds and 41 marine mammals. This island has a good percentage of them, and already research has thrown up surprises, -  and awesome submarine video footage of great clarity and beauty. Where are the artists?  Fox fish, weever fish, and Lord Howe Island coral fish are not familiar names to many here, nevertheless we have them. Snake eels and manta rays - the list goes on.  Dolphins, whales and, increasingly, fur seals are to be found around the coast.

 

The intertidal zone is the richest area of all. Highly oxygenated, loaded with nutrients, many species just have to be there! - Hence the stunning variety of birds attracted to feed on them. In the Kaitoke Swamp system salt water intrudes kilometers inland, (and yes, there are marine mussels in the middle of that swamp), often overlaid with lighter but colder freshwater.  Native freshwater fish inhabit from high-altitude headwaters of streams down to the lowland wetlands and stream mouths. The absence of the exotic mosquito fish popular in mainland private ponds is a major factor in the island's high freshwater fish and stream invertebrate diversity. It is quite probable more native fish species will be found, as relatively little survey work has been done. The black mudfish, and giant kokopu are at least two of the possible candidates for rediscovery. Native freshwater mussels use some fish species to carry their larvae back up the streams. The regenerating forest cover along stream margins cool stream waters allowing oxygen levels to rise and makes for higher fish and invertebrate diversity and density. 

 

Although invertebrates number in the thousands, and the diversity of their form, behaviour, and size can be daunting to take in, much has recently been learnt from an increase in surveys and research despite a shortage of taxonomists to identify them. Wherever rodent eradications take place, invertebrate numbers skyrocket, providing food for lizards, frogs, birds, bats, fish, and other invertebrates. The island is home to the strange and the weird such as giant worms, paua slugs and minute snails, giant centipedes, wetas, stick insects, leeches, spiders, butterflies, solitary native bees, giant puriri moths, the ancient peripatus, and much else. Glow worms are a common sight along forest tracks at night. Freshwater crayfish and great varieties of other animals inhabit the streams, whilst the sea hosts its own multitudinous forms. 

 

There are insect-eating long-tailed bats here, and most probably also the short-tailed bat, but finding it is dependant on also finding the rare native parasitic woodrose known to exist from the tantalising evidence of its fresh pollen and supported by many anecdotal reports. These bats are attracted by the pungent aroma of the plant's nectar. If the bat is found there could also be a rare wingless fly in their roosts. Bats make up a quarter (about 900) of all mammal species. 

 

Eight skink and five gecko species are known to occur on the island, as well as one native and one exotic frog. The Chevron skink, NZ's largest, is now known only from here (apart from a single specimen found on Little Barrier) and the subject of much research. Several other lizard and possibly one or two more frog species may yet be found through more surveys and locals being more familiar with what may seem unusual. If you sit quietly on a boulder beach such as is found around parts of the south-east and east of the island, you may find yourself being examined closely by seemingly intelligent, numerous, almost black, shore skinks

 

The woodrose is but one possibility amongst several when considering the rediscovery of flora on the island. The complete vascular plant list numbers 577 species as of 2002.  17 species have been added in the last 24 months! For instance, there is a possibility, (who knows how remote?), of rediscovering the Adam's mistletoe so ably recorded on canvas by Fanny Osborne, an early Barrier artist. Much remains to be recorded of the island's lichens, mosses, liverworts and fungi.

 

The island's size and diversity of ecosystems provide habitats for a high number of native bird species, including some quite rare, while several private rodent and cat-free sanctuaries have locally increased densities of some species further, along with lizards and invertebrates. Amazingly, bird-watchers haven't really discovered this island yet. You can see birds here that you'd rarely or never see on the mainland. Some such as the kaka and banded rail are common sights.  Come out and see for yourself. You won't be disappointed!

 

 Don Armitage © 2002.

 

 

Great Barrier Island Round-up

 

The hunt for and discovery of species not before found on Great Barrier has recently had both successes and failures.

In mid-March two Tryphena residents and their visiting relatives noticed at Pah Beach a 40mm long dark blue fish with two different-sized pairs of delicate transparent blue rayed wings shaped like a butterfly. A careful description was vital in its identification by a fish scientist at Te Papa. It was found to be a juvenile flying fish, which are extremely rare (or rarely collected) in NZ waters - there being only 3 specimens under 100 mm in length to study. They are thought to live in association with floating weed or debris and drift in the plankton until they develop into the adult form, at which stage the fin rays become thicker and more rigid, and the pattern of lines and dots on the fins is lost.

 

Hanging vertically amid the weed just out from Mulberry Grove School, what is thought to be the Smooth Pipefish has been seen by several divers. It is a yellow seaweed colour, about 250mm long and shaped like a straight and narrow seahorse less than the thickness of a pencil. Though common south of Hawke Bay there are few specimens from north of  the Bay of Plenty, and it is possible that these records are based on a different species, either undescribed or an Australian species.

 

New Zealand has about a thousand fish species, (more than a tenth of which are found nowhere else i.e. endemic), 2000 molluscs, 350 sponges, 400 echinoderms (sea eggs etc), 900 seaweeds and 41 marine mammals. This island has a good percentage of them .

 

A couple of fish, one the Bridled Goby, recently arrived in the estuaries of the Hauraki Gulf from Australia, and the other possibly the Black Pipefish from Japan both need to be checked up on for their presence here. The Bridled Goby either digs its own burrows or takes over crabs' burrows in quiet estuarine waters near the base of mangroves. A wide ranging study is under way to assess its likely impact. Beach-seining over eel-grass beds recently showed up the Black Pipefish in the Whangapoua Estuary on the Coromandel Peninsula so it may well be here in Puriri Bay. Last year the rare single-shelled marine slug Umbraculum was found living quietly, (they are very sedentary) on the island's east coast, not far from where I saw the largest Scutus I have ever seen (another black-footed marine snail with a shell hidden within a slitted cover. 

A good report of leeches at the head of the Kaitoke Swamp is no surprise, although the fact of a large study of their use going on at Green Lane Hospital may be.  (It sounds like it may be Richardsonianus mauianus). For instance putting leeches on the end part of a  rejoined finger that the dog didn't get first, helps to circulate blood through the graft area improving recovery of blood vessels and the "taking" of the graft, and there is some benefits to heart patients too. Their widespread use in past centuries in Europe may confirm some ancient wisdom. (With no disrespect to our local doctors, I found that medical physicians of old were at one time also called leeches). To get some specimens, simply walk about with bare legs up to your knees and not much further in fresh water amongst the rushes. Better than a disprin, they will thin your blood and reduce the chances of a heart attack. I can confirm there are no leeches in the part of the swamp nearest the police station although there are, unsurprisingly, fern birds in the area. 

Further offshore around Rakitu Island, Lizard fish, Lord Howe Coral fish and Rainbow Wrasse have recently been sighted. Some of the younger divers on the island, especially those in the newly-formed local diving club, may like to keep their eyes open for any of these underwater novelties, especially the pipefish and gobies. 

 

The visit by a large group from the  Auckland Botanical Society in January found yet another native orchid species on the slopes of Te Ahumata, while they confirmed the identity of another native fern found by a local resident who knows his plants. A report on the trip is due out imminently. There could be another 30-40 native species yet to find here, so please keep your eyes open. Also visiting seem to be increasing numbers of overseas ecology students studying the island as part of courses.

 

A study of the Brydes whale population in the Hauraki Gulf is nearing its end and some interesting things have emerged from it which I'm sure we'll hear about shortly. The Hauraki Gulf is in the middle of  the whales' range from North Cape to East Cape. Their numbers are thought to be small, although they may be continuous with other Brydes populations.

 

An on-going entomological survey around the island by staff at Auckland Museum is steadily adding valuable information about our invertebrates, including notice of healthy populations of native black katipos on the dune systems. A visit by a scientist sampling for mosquito fish thankfully found nothing, which is about all we have heard of the extensive Auckland University archeological survey here. And a note on a fly we have here. You may have noticed on occasion a large black fly that looks like it has windows in its carapace for some unfathomable reason. It is called the American soldier fly because it first arrived here with American troops aboard their ships during world war two. As far as I know it has no undesirable behaviours, unlike the Australian white-tailed spider that seems to be widespread across NZ. If bitten, it pays to hop along to the doctor. Its venom is not usually so bad as the bacteria that accompany it. 'Stingose' neutralises the venom and good to have in the home first-aid kit 

 

In mid-April several hardy souls met at Okiwi School to go looking for the parasitic plant Dactylanthus, more commonly known as the woodrose. A botanist, two of whom had come to the island especially, accompanied each of the three parties and several hours of hunting failed to find the plant, despite the widespread pollen found recently around the Whangapoua Estuary…very disappointing. The BBQ afterwards was much appreciated. A junior member of one of the parties found a landsnail tentatively identified as Rhytida greenwoodi, about 20mm across, and related to the Kauri Snail. Although it may have been often seen, reporting these sorts of finds adds to our knowledge of the islands flora and fauna. The records contained only one sighting ever. If you see something odd or unusual, I'd certainly like to know. The late Jim Gaulston carried out the most extensive landsnail survey so far back in 1991, and now a local resident is collecting snails and having them identified in her area. 

 

Recent weeks have seen a visiting Royal Spoonbill and a pair of red-crowned kakariki at Okiwi, a group of Australian cattle egrets flapping about near Charlie's pond, and a bittern that has been seen occasionally at Medlands. A very large chevron skink has been sighted at Rosalie Bay.

 

New information about the early days of the Copper Mine here have been received, part of a continuing and valued spin-off from the book on this island. An article by some early residents describing the past state of the local fishery would be interesting to read.  Well, that's a bit of a round-up of various historical and natural history matters that come past me.

 

Don Armitage © First published July or August, 2002.