How do we decide which endangered species to save?

Thursday, 12 July 2018

Conservationists pour money, time and energy into saving individual species. Why not shoot for entire ecosystems? In the second part of a two-part series, Charlie Mitchell examines the different ways of choosing which endangered species to save.

Strings of bracketed phrases, dancing with information from vast spreadsheets led to this. The 150 species listed by the Department of Conservation (DOC) as 'priority species', marked out as the most urgently in need of protection to avoid extinction.

It included Kiwi, Kākāpō, Hector's Dolphin, the Great White Shark and Tuatara; species that are generally considered important for conservation, animals that people know and like. But little known species like the fish guts plant and the swamp helmet orchid also made it. Kauri and Weka didn't. A computer algorithm, which weighted a range of factors, produced the final cut, released in a proposed strategy last year.

* Ten of New Zealand's forgotten critters**

The path towards prioritisation has been fraught, particularly within DOC, which has to juggle political and cultural considerations with its role as a science-led agency, along with funding restraints under the last Government.

Prioritisation is one of the most significant developments in conservation since DOC was created, and underpins much of the decision-making within the department.

There are two major strands of prioritisation: Species and ecosystems. They were developed separately, but are increasingly integrated.

Some within DOC preferred the ecosystem-driven approach. When you save an ecosystem, you protect all of the species within it, regardless of whether they're birds or earthworms; you don't need to wade into the politics of ranking species on merit.

Moana Uta Marine Reserve, one of Fiordland's 10 marine reserves, gives protection to the entire ecosystem under the surface.

The department's ecosystem prioritisation tool is effectively a map of New Zealand divided into units. Click on a unit and it tells you its ecosystem type, the species that exist within it, and the cost per hectare to manage its threats. It gives you a prescription for what to do to maintain the area: It might prescribe regular 1080 drops, or clearing exotic weeds, for example.

Those units enter a ranked list of importance, the top 400 of which represent virtually all ecosystem types.

The focus is on representation. Within DOC, picking ecosystems has been likened to choosing a cricket team. You need a range of skills - batters, bowlers, a wicket keeper. If your wicket keeper becomes injured, you don't replace them with your next best player, you replace them with another wicket keeper.

There are a few issues with ecosystem management. DOC can only control conservation land, which is about one third of the country - it needs to work with individual landowners to protect important ecosystems on private land. Another is that lots of work has been done in places that need less protecting than others. For example, DOC manages more than 500,000ha of land with alpine ecosystems, but only 387,000ha were identified as a priority in the ranked list. On the other hand, DOC manages 50,000ha of land with braided river ecosystems, but the list showed three times that much was needed.

Nicola Toki is DOC's threatened species ambassador.

When the Auditor-General examined these (then yet to be implemented) tools in 2012, this was raised as a key concern. What if DOC pulls out of projects in areas it partners with a community group, because the area no longer meets their optimisation criteria? What if the department has spent decades working on restoring a landscape the centralised computer says is no longer a priority?

The other issue is that ecosystems are a hard sell. There's an obvious appeal to a priority list that features everyone's favourite birds, as opposed to one that highlights the need for better threat management within ultramafic ecosystem units.

That's why the threatened species algorithm was introduced. It is an extra step to manage species that may not appear in a highly threatened ecosystem, or has particular needs. If ecosystem protection is the fence at the top of the cliff, species protection is the ambulance waiting at the bottom.

'It's tricky because we have such a massive affinity for our wildlife,' says DOC's Threatened Species Ambassador Nicola Toki.

'We've entirely connected our national identity to our wildlife and our wild places, and people want to see us protecting the things they are passionate about.

In 'The ark and the algorithm', Stuff's Charlie Mitchell examines how we decide which endangered species to save.

'It's harder to fall in love with an ecosystem. People have an affinity for species, particularly animals, but healthy, flourishing ecosystems allow us to protect the species within them and continue to drive the health of that ecosystem, which has ongoing benefits for the surrounding areas.'

The idea behind the algorithm was that it would be a middle ground, of sorts. It would make sure the species people know and love made the list, alongside others that needed particular protection.

Fifty species automatically made the list based on their 'iconic' nature, drawn from data DOC had collected previously from phone surveys and focus groups.

It's a predictable list. They are mostly birds, starting with 'k'. The rest were chosen purely on merit, as determined by the algorithm.

The response to the list was polarised. The public submissions made a range of arguments: That it protected too few species, or neglected one in particular the submitter liked. But the most common complaint was the special status given to the 'iconic' species. All these tools had been developed to make hard decisions objectively, and yet it still came down, at least in part, to a popularity contest.

It has long been a complaint in conservation circles there's a clear bias from authorities towards certain species, driven by public demand. Conservation funding is not an even playing field; Kiwi will always beat Smeagol climoi, a native gravel maggot, in a popularity contest, even though the latter is more threatened.

Raising the profile of those smaller, obscure species has been a long-running challenge for conservationists. We know that ecosystems strike a precarious balance: For example, native flies are prolific pollinators of plants, which feed bugs, which feed larger species. If the flies become extinct, it could throw the entire system off-course.

It's not something New Zealand has done well in the past, said Dr Andrea Byrom, director of the Biological Heritage National Science Challenge.

'My view is that we do not do enough work in New Zealand to fully understand how our systems work,' she said.

'If I was to advocate for a particular focus, I would focus on keystone species we know have a big role in the system. If we focus on species prioritisation alone, it's almost a hiding to nothing.

A Hamilton's frog. Only around 300 are known to exist.

'There's got to be other mechanisms for how you do that sort of prioritisation - for example, the role of a species in an ecosystem context. Is it providing food for another species? Is it providing habitat? That sort of thing. Those are really important considerations to take into account.'

Byrom would like to see a 'biodiversity forecast' on the television news, in between the weather and the stock market results, that would show how our native species were doing. It would list those that were improving, and the many others that were falling, highlighting the plight of our lesser known species and the grim fact that 'you can't save everything'.

There was still a place for social factors in conservation, Byrom said, it just shouldn't be the only thing we value.

'There is a risk of only focussing on the iconic invertebrate and bird species, but on the plus side, there's a social dimension that raises awareness,' she said.

'How you get that balance between raising the awareness of something that's less of a priority overall but resonates, versus something that's really cryptic and unseen and doesn't resonate but may play a vital role in an ecosystem … we're struggling with that as a nation, I think.'

The endangered katipo spider, whose Maori name translates 'night stinger''.

'THERE'S A LOT WE DON'T KNOW'

The problem with a tool like the algorithm is that it needs data. For it to work, you need to know as much as possible about a species - how many there are and what taxon it belongs to. New Zealand has tens of thousands of species we know very little about.

There are an estimated 90,000 native species we know exist, but only just over half of those have been formally described. Of the ones we know about, many are 'data deficient'. We don't know how rare they are, or even if they're unique to New Zealand.

'It's the nature of the way science is funded in New Zealand,' says Dr Cor Vink, curator of Natural History at Canterbury Museum.

'We don't fund basic taxonomy very well in New Zealand. Nowhere really does. It's hard to get funding to go out and name species, you usually have to jazz it up and add some other fancy research around it … It is a big problem.'

In Vink's specialty area, spiders, around 700 of our 2000 native species have yet to be described, he said. Given around 95 per cent of our spiders are found nowhere else, that's hundreds of unique species we know virtually nothing about.

It's worse for insects - around 7000 species have yet to be formally described. These are species that, for all we know, could be critically threatened or even functionally extinct.

Saving the Kākāpō meant sacrificing the far less glamorous Stringopotaenia psittacea.

New Zealand has the expertise to describe those species, Vink says, it just hasn't been willing to fund the work properly. For prioritisation to work, we need as much information as possible, and we need to know which species we're losing or about to lose.

'There's a lot we don't know, and we'll potentially lose a lot without even knowing we're losing them,' he says.

It also leaves us with holes in our understanding of how ecosystems work. New Zealand's spiders, he says, eat around 142,000 tonnes of insects and other arthropods annually, which is roughly half the mass of what our human population eats in a year.

If spiders are disappearing, that's a big problem. We can't know how quickly they're disappearing if there are hundreds of species we still don't know about.

Conservation in the modern age is inherently about choice. Funding one thing deprives another of resources, which could lead to its extinction.

Vink points out a stark example: The effort to save the Kākāpō from extinction has directly led to the extinction of another species.

We once had a native species called Stringopotaenia psittacea, a tapeworm only known to use Kākāpō as its host. The intensive management of Kākāpō means they are regularly de-wormed, and Stringopotaenia psittacea is now likely extinct.

Few are likely to have sympathy for a tapeworm: It never appeared on a stamp or a tourism poster. But it's a species only found here that is now gone forever.

Since human settlement, around 70 native species are known to have become extinct. Most of them were birds - like Moa, Haast's Eagle, and the Laughing Owl - but we've also lost frogs, snails, worms, plants and a bat.

At last count, more than 3000 native New Zealand species were deemed 'at risk', a figure hugely out of proportion with the country's size - the United States, for comparison, has 1300. Around 900 of those at risk in New Zealand are in the more dire stage of 'threatened'.

It means our rate of threatened species is among the highest in the world, and that's only the ones we know about. It is likely species we don't even know exist are going extinct all around us.

The list of priority species is a case study for how entry onto the Ark could be decided, in a country where the stakes are unusually high. If a species dies, it is likely to be gone forever.

'I think that's where DOC managers and rangers are probably super glad we have a department that can create things like the ecosystem prioritisation project, the algorithm, which objectively describes the situation you're dealing with and allows you to make a decision with the benefit of that information,' Nicola Toki says.

'If you think of New Zealand as a lifeboat for this kind of wildlife that can't be replicated anywhere else in the world, then it's our responsibility to give it our best shot to look after those things. We have this international obligation to make sure we're protecting those things that are found nowhere else in the world.'

The species ranked 151st on last year's priority list was Barker's koromiko, a small tree on the Chatham Islands only just clinging on to survival.

The New Zealand fish-guts plant ranked only a few places higher.

Which one is most worthy of our protection? Someone has to decide.