Powelliphanta: Difference between revisions

Powelliphanta snail
Conservation status
	Template:StatusEndangered
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Orthogastropoda
Superorder:	Heterobranchia
Order:	Pulmonata
Suborder:	Eupulmonata
Family:	Rhytididae
Genus:	Powelliphanta
Species
	See text.

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Revision as of 17:58, 30 December 2006

The shell of a species of Powelliphanta land snail.

Powelliphanta is a genus of giant, carnivorous land snails endemic to New Zealand. They live mostly in tiny pockets of moist native bush in small areas of the North and South Islands, with the greatest diversity of species in the mountains of northwest Nelson. They are sometimes known as amber snails.

There are 21 species and 51 subspecies. The relationship between the species is complex, and it has been suggested that the group Powelliphanta gilliesi-traversi-hochstetteri-rossiana-lignaria-superba forms a ring species. In November 2003 a subspecies, thought to be extinct, was rediscovered alive on the West Coast; it had last been documented on the basis of shell fragments in 1934.

These snails are real giants, with shells up to 9 cm across (Powelliphanta superba prouseorum).

Their striking delicately-patterned shells come in an array of shades, from brown or red to yellow or black. The structure of these shells is very delicate, with a very thin layer of calcium carbonate, covered by a thicker chitinous outer layer. That is why these snails need moist surroundings. Otherwise the outer layer (periostracum) dries up, shrinks and cracks.

They are carnivorous and eat mostly earthworms or slugs. They are nocturnal. They need moist surroundings and live buried under leaf mold and logs. They can live for 20 years or more and are slow to mature, reaching sexual maturity around 5 years of age. They are hermaphrodites, having both male and female characteristics. They lay 5 to 10 large eggs a year.

Their origin goes back 200 million years to the continent Gondwana. Through their isolation on New Zealand, they have evolved a unique set of characteristics. They are a testimony for New Zealand’s unique biodiversity.

An unspecified species of Powelliphanta recently appeared on a New Zealand 40-cent postage stamp.

Conservation status

The IUCN Red List states for Powelliphanta marchantii a lower risk, near threatened. But most of these snails are under serious threat or even in danger of extinction. They have no defense against introduced predators, such as Common Brushtail Possums, Trichosurus velpecula, and rats. Many recovery plans are being launched by the New Zealand Department of Conservation. The subspecies Powelliphanta gilliesi brunnea and Powelliphanta traversi otakia are the most threatened.

Since 2004, plans by Solid Energy to destroy the main habitat of Powelliphanta Sp.Augustus while mining for coal have caused controversy, and the species is critically endangered with only between 500 and 1,000 remaining.

Species and subspecies

Undescribed species

Undescribed subspecies

Notes

External link

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 <div style="float:right;">[[Image:Powelliphanta shell.jpg]]<br><small>The shell of a species of ''Powelliphanta'' land snail.</small></div>
-'''''Powelliphanta''''' is a genus of giant, carnivorous land snails [[endemic (ecology)|endemic]] to [[New Zealand]]. They live mostly in tiny pockets of moist native bush in small areas of the [[North Island|North]] and [[South Island]]s, with the greatest diversity of species in the mountains of northwest [[Nelson, New Zealand|Nelson]] . They are sometimes known as '''amber snails'''.
+'''''Powelliphanta''''' is a genus of giant, carnivorous land snails [[endemic (ecology)|endemic]] to [[New Zealand]]. They live mostly in tiny pockets of moist native bush in small areas of the [[North Island|North]] and [[South Island]]s, with the greatest diversity of species in the mountains of northwest [[Nelson, New Zealand|Nelson]]. They are sometimes known as '''amber snails'''.
 There are 21 species and 51 subspecies. The relationship between the species is complex, and it has been suggested that the group ''Powelliphanta gilliesi-traversi-hochstetteri-rossiana-lignaria-superba'' forms a [[ring species]]. In November 2003 a subspecies, thought to be extinct, was rediscovered alive on the West Coast; it had last been documented on the basis of shell fragments in 1934.
@@ Line 35: / Line 35: @@
 The IUCN Red List states for ''Powelliphanta marchantii'' a lower risk, near threatened. But most of these snails are under serious threat or even in danger of extinction. They have no defense against introduced predators, such as [[Common Brushtail Possum]]s, ''Trichosurus velpecula'', and [[rat]]s. Many recovery plans are being launched by the [[New Zealand Department of Conservation]]. The subspecies ''Powelliphanta gilliesi brunnea'' and ''Powelliphanta traversi otakia'' are the most threatened.
+Since 2004, plans by [[Solid Energy]] to destroy the main habitat of ''[[Powelliphanta Sp.Augustus]]'' while mining for coal have caused controversy, and the species is critically endangered with only between 500 and 1,000 remaining.
-Since 2004, plans by [[Solid Energy]] to destroy the main habitat of ''Powelliphanta "augustus"'' while mining for coal caused controversy (see [[Save Happy Valley Campaign]]). Solid Energy, whose past mining activities had already significantly reduced the species' habitat, plan to mine the skyline ridge including Mt Augustus.  In May 2005 they sought a permit from the Department of Conservation to translocate some ''Powelliphanta "Augustus"'' but intended to begin mining regardless of whether the permit was granted or not.  The [[Royal Forest and Bird Protection Society of New Zealand|Royal Forest and Bird Protection Society]] obtained a declaration in December 2005 from the High Court requiring Solid Energy to get permission from the Minister of Conservation and the Minister of Energy for this translocation, as well as any transfer of heavy machinery, and any impact on habitat. Permission was granted in April 2006 for this translocation plan.<ref>[http://www.scoop.co.nz/stories/PA0604/S00233.htm Permits approved to move Mt Augustus snails]. NZ Government press release, [[12 April]] [[2006]]</ref> This was condemned by Forest and Bird, by the Save Happy Valley Coalition [http://www.savehappyvalley.org.nz/pressreleases/pr_12-04-06_shvc.htm] and by the [[Green Party of Aotearoa New Zealand|Green Party]],<ref name="Greens">[http://www.greens.org.nz/searchdocs/PR9744.html Snails sold out by State to Solid Energy]. Green Party press release, [[12 April]] [[2006]].</ref> in part because of significant doubts as to whether the translocation would succeed, and the lack of guarantee that this measure would protect the species from extinction.  ''Powelliphanta "augustus"'' numbers are estimated to be less than 500, and their existing habitat covers 3 to 4 [[hectare|ha]].  The Wildlife Permit grants Solid Energy permission to mine 96% of this area. There is also concern over the destruction of ''Powelliphanta'' habitat by the mining company [[OMYA]] on [[Mount Burnett, New Zealand|Mount Burnett]], in [[Golden Bay]].
-On 4 December 2006 twenty snails removed from Solid Energy's planned opencast mine expansion at Stockton were released back into the wild.
-A further 20 snails collected from the ridgeline of the mine site were also released about 800 [[metre|m]] from where they were found.
-The giant carnivorous snails, ''Powelliphanta "augustus"'', were released into an area of the Stockton Plateau that will not be mined.
 ==Species and subspecies==