Although New Zealand has a long history of attempting to reintroduce native species into their former habitats, projects have been poorly conceived, poorly monitored and had poor success, say a group of New Zealand's leading reintroduction biologists.

A new book, titled Advances in Reintroduction Biology of Australian and New Zealand Fauna, casts a critical eye on species re-introduction - releasing some of our most vulnerable native wildlife back to into their former habitats.

It outlines the progress in research aimed at improving this practice, and illustrates how sciences such as population ecology and genetics can be used to predict the fates of re-introduced species.

The project was led by Professor Doug Armstrong, Oceania Chair of the Reintroduction Specialist Group and Professor of Conservation Biology at Massey University, but is a collaboration between 70 reintroduction biologists working on projects throughout Australia and New Zealand.

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He answered a few questions from the Herald.

1) What was the reason for writing this book?

The big impetus was actually an anniversary.

In 1993 a conference was held to get people working on reintroductions in the Australasian region together, and this led to a 1995 book.

This was the birth of reintroduction biology and in fact the term "reintroduction biology" was coined through the conference.

The field was in its infancy at that stage, and mainly involved comparing notes from case studies.

This is no longer the case, so 20 years later we wanted to get everybody together again, and put our advancements in reintroduction biology together in an accessible volume.

2) Part of its focus is on the re-introduction of threatened, native species back into nature. Your book finds there is room for improvement in present practice. Where are we currently failing and what can we improve?

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That's the main focus, although the species concerned are not necessarily considered threatened on a national or global scale.

In New Zealand, most current projects are conducted to restore species to local ecosystems rather than necessarily to save those species.

Regardless of the motivation, the trap many projects fall into is focusing on the immediate capture, transport and release of the animals, but not what's likely to happen to the population or ecosystem in the long term.

The media coverage is even worse -- we see countless stories of people releasing animals from boxes, but I can't recall a single story doing a follow-up.

For reintroduction to be truly successful, we have to be able to assess, firstly, what's the probability that the population will actually establish and grow, secondly, whether it is likely to be viable in the long term, and thirdly, what, if any, management will be required.

We now have good science in place for addressing these questions -- some projects are making good use of these advancements whereas others continue to open boxes and hope for the best.

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The book gives good examples from lots of programmes.

In New Zealand a great example is the hihi (stitchbird) recovery programme, where the species has gone from one to six populations through intensive management underpinned by population modelling and decision analysis.

In Australia a great example is the clever translocation programme put in place to save a species facing a really nasty disease threat.

3) Part of the book also looks at the concept of a predator free New Zealand. This concept has been advanced by many of our thinkers, from the late Sir Paul Callaghan to Gareth Morgan. Is it possible to return our country to a place the way it was, where introduced predators weren't around to pose the threat of extinction to many of our native birds, mammals and reptiles?

The idea of predator-free New Zealand has been developing over about 50 years, with the scale of eradication gradually increasing over time.

These eradications create opportunities to reintroduce species, and most of our successful reintroductions to date have been to offshore islands where mammals like rats and stoats were eradicated.

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More recently these pests have been eradicated from fenced mainland sanctuaries like Maungatautari, but there are also many larger-scale projects where pests are being successfully controlled rather than eradicated.

So can we scale up further and eradicate rats and stoats from the North and South Island?

The answer is probably yes, but whether it will ever happens will depend mostly on peoples' values.

It is probably already feasible to eradicate rats and stoats from Stewart Island for about the same cost as the flag referendum.

But there are currently huge political obstacles that need to be removed before these eradications can happen.

The benefits are hugely influenced by the reintroductions we could do if these eradications took place, so reintroduction potential should be a big part of this conversation.

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4) The book touches on the rather intriguing subject of de-extinction, or resurrecting recently extinct species like the Huia. What are the scientific possibilities we have around this concept - and why is it important that such opportunities should not lessen the task we have of preserving the species we have that are still alive but are on the brink?

The genetic technology is coming, but it's pointless if we haven't thought through the feasibility of actually reintroducing the species to the wild and attempted to predict the long-term consequences.

So while the genetic technology is fascinating, the more interesting and challenging science is actually the ecological issues concerning reintroductions. Huia are a good example, as there is probably a good case for reintroducing them and we should be able to make pretty good predictions as a result of the work we've done with other forest bird reintroductions.

But indeed I see it as absolutely critical that any investment in de-extinction doesn't compromise surviving species.

This is especially the case in New Zealand, where most species have declined to a fraction of their former ranges over the last 150 years, but few (that we know of) have become completely extinct.

So it's a bit of no brainer here that our investment should be recovery the many rare species rather than worrying about the extinct ones.

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5) Why is it crucial for New Zealand to have the conversations raised by this book today - and what responsibility do we have to the rest of the world to retain the myriad species that come with our comparatively enormous rate of endemism?

The book focuses on how we can best pursue our reintroduction programmes, getting the best bang for our buck in relation to peoples' values.

What those values should be is a broader conversation that involves everybody.

But biologists need to remind people that being a tiny archipelago that split from the rest of the world 80 million years ago, New Zealand biodiversity is the closest thing to life on another planet.