The Ethnic Cleansing of Nature: Who will protect native hybrids from the Department of Conservation?
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The rare Forbes Parakeet hybridises
with its red crowned cousin. For DOC
the hybrids have no 'intrinsic value'.
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In New Zealand it is open season on some native hybrids. RAY GENET looks at the issues surrounding the Department of Conservation’s (DOC) attempts to protect the genetic purity of the endangered Forbes parakeet and the black stilt, and discusses them with world renowned conservation biologist Michael Soulé and ecologist Ashley Sparrow.
A few years ago I was shown a photograph. It was of a hut set in native bush on Mangere Island in the Chathams, a small collection of islands some 700 km from east coast the South Island of New Zealand. On the veranda were two neat rows of recently shot native parakeets. Seated behind the carcasses, with .22 rifle in hand, was a Department of Conservation worker. It was all in a day’s work.
Some of the dead were native Chatham Island red crowned parakeets (or kakariki), but most were crosses between this bird and its close, but scarce relative, the Forbe's parakeet. It is assumed that interbreeding began after the two populations were brought together through habitat modification early in the twentieth century. The culling of the Chatham Island red crowned parakeet, and its ‘half-caste’ progeny began in 1976 to prevent the Forbes parakeet being hybridised out of existence. In that year the Wildlife Service shot 300.
“Removal” to prevent the mixing and competition by native species is standard DOC policy. In the successful attempts to salvage the black robin, its close relative the Chatham Island tomtit was shot out of Mangere Island.
If you look up the Chatham Island red crowned parakeet in the Ministry for the Environment’s ‘State of the New Zealand Environment 1997’, it is listed as “seriously threatened with the second highest conservation priority”, that is it is a “category B” species ”. Before 1994 it had no such status.
One could be forgiven for thinking that the Department of Conservation itself is a major factor contributing to its threatened status.DOC’s management of the parakeets is not without its critics. Not so long ago in a leading ecological journal, eminent American conservation biologists Judith Rhymer and Daniel Simberloff warned of the dangers of ignoring the benefits of hybrids.
In the event of the sudden extinction of either parent species, crosses would be a valuable source of genes, and through controlled breeding could be used to reconstruct them. Furthermore, they are sometimes more robust and better adapted to the modified environment than their parents. The implication is that, if for some reason the reconstruction of the parent forms is impossible, a cross-bred parakeet is better than none at all.
DOC's reaction to criticism is: "Strange"
In charge of the Chatham Islands is Wellington District Conservator, Allan Ross. He is aware of the criticism but is unmoved. Furthermore he sees making an association between the culling of the Chatham Island red crowned parakeet and its appearance on the list of threatened species as “strange”.
“Its category ‘B’ status has nothing to do with the control taken on some populations of it. There are viable populations of red crowned parakeets and we feel it’s reasonable that the population is not so endangered that we can’t thin it out in favour of Forbes parakeet. It is listed as a category ‘B’ species because care and caution is required with it and it is certainly not one we can walk away from and say the species is going to look after itself everywhere.”[
[In 1999, Conservation Secretary, Brian Sheppard said he was confident that the department was doing the right thing. Nevertheless, in 2001 after enquiries were made for the writing of this article the project was called up for review and overhaul. As a result a three year moratorium on the culling was imposed, on at least Mangere Island. During this time research into the genetics and breeding ecology of the Chatham Island red crowned parakeets, Forbes parakeets and their hybrids was undertaken. The project will be reviewed again in 2011.]
Is the all Black Stilt extinct?
Hybridisation is also a considered problem on the mainland. The Black Stilt Recovery Project in Central Otago uses similar “destructive management”. Driven to near extinction by habitat loss and introduced predators, the black stilt is reported to be one of the rarest wading bird in the world. Now confined to the Mackenzie Country they flock together with their black and white Australian ancestors, the pied stilt. With so few of their own kind left to choose from, black stilt females choose to form their life long bond with their pied relatives.
A few years ago I was shown a photograph. It was of a hut set in native bush on Mangere Island in the Chathams, a small collection of islands some 700 km from east coast the South Island of New Zealand. On the veranda were two neat rows of recently shot native parakeets. Seated behind the carcasses, with .22 rifle in hand, was a Department of Conservation worker. It was all in a day’s work.
Some of the dead were native Chatham Island red crowned parakeets (or kakariki), but most were crosses between this bird and its close, but scarce relative, the Forbe's parakeet. It is assumed that interbreeding began after the two populations were brought together through habitat modification early in the twentieth century. The culling of the Chatham Island red crowned parakeet, and its ‘half-caste’ progeny began in 1976 to prevent the Forbes parakeet being hybridised out of existence. In that year the Wildlife Service shot 300.
“Removal” to prevent the mixing and competition by native species is standard DOC policy. In the successful attempts to salvage the black robin, its close relative the Chatham Island tomtit was shot out of Mangere Island.
If you look up the Chatham Island red crowned parakeet in the Ministry for the Environment’s ‘State of the New Zealand Environment 1997’, it is listed as “seriously threatened with the second highest conservation priority”, that is it is a “category B” species ”. Before 1994 it had no such status.
One could be forgiven for thinking that the Department of Conservation itself is a major factor contributing to its threatened status.DOC’s management of the parakeets is not without its critics. Not so long ago in a leading ecological journal, eminent American conservation biologists Judith Rhymer and Daniel Simberloff warned of the dangers of ignoring the benefits of hybrids.
In the event of the sudden extinction of either parent species, crosses would be a valuable source of genes, and through controlled breeding could be used to reconstruct them. Furthermore, they are sometimes more robust and better adapted to the modified environment than their parents. The implication is that, if for some reason the reconstruction of the parent forms is impossible, a cross-bred parakeet is better than none at all.
DOC's reaction to criticism is: "Strange"
In charge of the Chatham Islands is Wellington District Conservator, Allan Ross. He is aware of the criticism but is unmoved. Furthermore he sees making an association between the culling of the Chatham Island red crowned parakeet and its appearance on the list of threatened species as “strange”.
“Its category ‘B’ status has nothing to do with the control taken on some populations of it. There are viable populations of red crowned parakeets and we feel it’s reasonable that the population is not so endangered that we can’t thin it out in favour of Forbes parakeet. It is listed as a category ‘B’ species because care and caution is required with it and it is certainly not one we can walk away from and say the species is going to look after itself everywhere.”[
[In 1999, Conservation Secretary, Brian Sheppard said he was confident that the department was doing the right thing. Nevertheless, in 2001 after enquiries were made for the writing of this article the project was called up for review and overhaul. As a result a three year moratorium on the culling was imposed, on at least Mangere Island. During this time research into the genetics and breeding ecology of the Chatham Island red crowned parakeets, Forbes parakeets and their hybrids was undertaken. The project will be reviewed again in 2011.]
Is the all Black Stilt extinct?
Hybridisation is also a considered problem on the mainland. The Black Stilt Recovery Project in Central Otago uses similar “destructive management”. Driven to near extinction by habitat loss and introduced predators, the black stilt is reported to be one of the rarest wading bird in the world. Now confined to the Mackenzie Country they flock together with their black and white Australian ancestors, the pied stilt. With so few of their own kind left to choose from, black stilt females choose to form their life long bond with their pied relatives.
In a programme known euphemistically as “matrimonial rearrangement”, pied and hybrid males that mate with black females are shot in the hope that the female will reselect a mate of the right colour.In 1996 an audit of the project revealed that some black stilt females were carrying pied stilt DNA; that is, they were “cryptic hybrids”.
This led to fears that the bird was technically extinct. It was decided that before continuing the project the exact number of “cryptic hybrids” should be determined, as well as whether it is feasible to prevent further interbreeding.
In defence of the project Brian Sheppard says the project persists because recent research failed to find any trace of the “cryptic hybrids”. Further the department is confident that its actions are based on sound scientific principles, and given new guidelines it feels sure it can reach its objectives.
What is old is natural, what is natural is good
For DOC, the parakeet and stilt cases are clear cut. The department’s central role is to preserve representative samples of nature present before 1840. Known as the “1840 datum”, it is the benchmark for determining what is “natural” and what has “intrinsic value”. They believe that the Forbes parakeet and black stilt would not have hybridised had their habitats not been modified. As these couplings are artefacts of European disturbance they have no intrinsic value, and DOC feels compelled to intervene.
Post-modern conservation
Asked to comment on whether it is biologically sound to kill native hybrids, Dr. Ashley Sparrow senior lecturer in ecology at the University of Canterbury, does not believe the question is relevant to the argument.“It is both an ethical and aesthetic choice to conserve the [pre-1840] impacted form, and conservation in the DOC sense is aesthetic.”
He explains further that conservation often reflects the mood of society, and not the concerns of some 'ideal' ecology. Conservation in New Zealand is sometimes motivated by nationalistic sentiments. Birds such as the kiwi, white heron and the black stilt are highly valued because they set New Zealand, and somehow New Zealanders apart from the rest of the world. The current mood in society is postmodernist, where what is right, good or bad is determined by consensus. Species selected for conservation may one day be determined in this way.
A Strange New World
Professor Michael Soulé, now retired from the University of California in San Diego, is the leading authority in conservation biology. He does not believe that the postmodernist theme will take hold.
“The pendulum will swing back away from multi-cultural relativism and extremely pseudo-democratic values, back to national parks. The only salvation for nature, particularly in tropical countries, is large well defended national parks, everything else outside parks is going to go down the tubes.”
For him there is not an optimal solution to the parakeet issue, especially as habitat modification is involved. However he suggests that those involved consider “…that the world is changing very fast climatically and because of massive habitat disturbance, so who knows what’s going be best adapted to [this] strange new world. Perhaps a hybrid genome will adapt more easily to it.”
As for the possible loss of the black stilt through hybridisation:
“I wouldn’t applaud it, but I’d say that that kind of event probably is extremely common in nature even without people. I wouldn’t advise spending a lot of resources trying to reverse a natural event such as this. There are so many pressing conservation issues in New Zealand. As an American I know that governments typically don’t act rationally. I hope New Zealand is an exception. In my country, however, just a few species, because they are charismatic, receive most of the conservation dollars. The criteria are political not biological.”
Michael Soulé believes “1840 datum” as a goal for conservation is impractical. Owing to numerous irreversible environmental changes it is impossible to return, even representative pockets of New Zealand to their pre-colonial state.For Professor Soulé there’s no point in having a policy such as “intrinsic value” that has no operational meaning in science:
“My operational definition of “intrinsic value” in your situation might be: ‘Does a management decision or some standard tend to prevent extinction of species?’ Sometimes a hybridisation of species can represent extinction in a sense, but it can also represent on-going adaptive radiation, so [this definition] isn’t a clear touchstone for what is ultimately the most ethical way to behave, but I think it’s a good place to begin.”
The extinction equation
Conservation is a crisis discipline, and DOC’s management style in relation to the management of the hybrid problem of ‘shooting first and asking questions later’ reflects this. It may be time for the department to lower its rifle, and consider that to try and preserve what is “natural” by interfering with natural processes can only be counterproductive to conservation in the long run. In this case the Department of Conservation may eventually have to include itself as a factor in the extinction equation.
Completed June 1998 - revised June 2005
Further reading
‘Extinction by hybridisation and introgression’ by Judith M. Rhymer and Daniel Simberloff Annual Review of Ecology and Systematics (1996) 27: 83-109.
‘Forbes’ parakeet and Chatham Island red- crowned parakeet recovery plan 2001-2011. Threatened species recovery plan 45’. Published by the Department of Conservation, P.O.Box 10-420, Wellington, New Zealand.http://www.doc.govt.nz/Publications/004~Science-and-Research/Biodiversity-Recovery-Unit/PDF/TSRP45.pdf
‘Genetic status of New Zealand black stilt (Himantopus novaezelandiae) and the impact of hybridisation.’ Conservation Advisory Notes 239, Department of Conservation, Wellington. Wallis,G (1999)
‘Hybridization of the Habitat.’ By Edgar Anderson, Evolution (1947) 2.1 : 1-9
‘Live and Let Live’ by Martin Brookes. New Scientist (1999) pp 32-36 No 2193
‘Molecular genetic analysis of hybridisation, Science for Conservation: 105’. Department of Conservation, Wellington. Chambers, G.K. and E.S. Mac Avoy (1999)
‘State of the New Zealand Environment 1997’ Ministry for the Environment‘Technical audit of the Black Stilt (kaki) Recovery Programme’ by Alan Saunders, Andy Engilis jr and John Innis, February, (1996)
‘The Song of the Dodo, Island Biogeography in an Age of Extinctions.’ by David Quammen (1996). Pimlico/Random House, London, UK.
Return to Table of Contents
‘Molecular genetic analysis of hybridisation, Science for Conservation: 105’. Department of Conservation, Wellington. Chambers, G.K. and E.S. Mac Avoy (1999)
‘State of the New Zealand Environment 1997’ Ministry for the Environment‘Technical audit of the Black Stilt (kaki) Recovery Programme’ by Alan Saunders, Andy Engilis jr and John Innis, February, (1996)
‘The Song of the Dodo, Island Biogeography in an Age of Extinctions.’ by David Quammen (1996). Pimlico/Random House, London, UK.
Return to Table of Contents
