Sustain Episode 1: What can be done about invasive species?

Transcript

Al Glen: Sure, often people confuse the terms introduced species and invasive species, and
the key difference there is that invasive species are not only introduced to a place outside
their natural range, but they’re also harmful, either to the environment or to human health or
the economy.

Jacqueline Beggs: No, I think that’s a great definition. There are all sorts of different
languages you’ll hear, people will say alien invasive species, there’s a wide range of terms.
But I think Al’s definition is great, an invasive species, something that’s spread out of its
native range and causing harmful impact.

MA: What kind of harmful impacts are we talking about? Like, why does this really matter?
Why is there a big report coming out of the United Nations saying we’ve got a crisis with
invasive species?

**AG: Well, the impacts can be wide ranging and significant. These can be a massive
amount of economic impact, billions of dollars. There can be a huge amount of ecological
impact, species going extinct, species being impacted in so many different ways. And that’s
problematic when a lot of our biodiversity’s already in big trouble. And then the third strand
is of course, social impact. And there’s all sorts of effects on human well-being.

MA: Well, let’s maybe break down some of those things. Like you mentioned extinction, how
does that happen when there’s an invasive species?

JB: Well, anyone who saw the fantastic Radio New Zealand TV documentary a year or so
ago, Fight for the Wild, will have seen that New Zealand has been extremely hard hit by
extinctions. Over 50 New Zealand species of birds have already gone extinct and there are
dozens more species that are still threatened with extinction. And the major reason for a lot of
those extinctions has been invasive species, in particular because New Zealand was so
geographically isolated, the wildlife here evolved without any mammals.

AG: So, when humans arrived and brought mammals with them, that was an ecological
disaster. The native bird species didn’t have any of the sorts of defensive adaptations that
would allow them to escape mammalian predators, such as stoats and rats. And they were just
sitting ducks, they were just very easily exterminated by these new natural enemies.

MA: The natural birds that went extinct?

JB: That’s right. Literally sitting ducks, we lost many of our duck species, all sorts of
wonderful native species have already gone extinct. But as Al says, the real ongoing risk to
many of our native species is that the long-term trends are not good for so many species.
I think there’s around about 930 species in New Zealand that are classified as threatened,
and many of those species have no active management at all.

MA: You mentioned the need for multiple species for that term, biodiversity. But not a lot of
people understand why biodiversity is good. I mean, what is it about biodiversity that we
need to protect?

JB: Biodiversity underpins how our world operates. It’s biodiversity that helps create soils,
recycle nutrients, pollinate our crops. So many ecosystem services that they provide, but also
species have an inherent right to exist, that sense of wairua. What makes New Zealand
special is all our special plants and animals. And we surely wouldn’t want to lose those, even
if it’s not directly providing a direct thing. They are part of our world, and we are part of their world.

AG: I think Jacqueline just hit the nail on the head. It’s a priceless and irreplaceable heritage.
Once one of these species is lost, it’s lost forever. We can never replace that. In some cases,
that will have serious, tangible impacts for us. And in all cases, it’s just a terribly sad thing to
lose these incredible species. And one example that I think is quite poignant for Aotearoa
New Zealand is the huia, this fantastic bird with its striking big, curved bill, gone forever. It’s
really sad.

JB: I always feel a personal connection to the huia. When I look at a painting of my great-
great-grandmother a few generations back in the 1840s, there she is in her korowai, her cloak
and huia feathers in her hair. Huia were a part of her world in a way they can never be part of
my world now.

MA: It’s like you’ve been robbed of a piece of your heritage.

JB: That’s gone.

MA: Now, you also mentioned a few other things before we started recording that I thought
I’d re-mention. One is you said things like fire ants that are invading have real consequences
beyond, for example, what the mammals have done to the bird species. First of all, how do
they get here and what’s the problem?

JB: Insects are my specialty, and they’re one of the groups of species that are still very much
on the move around the globe because they’re small, they’re often cryptic, and they hitchhike
on human goods. It is really hard to have systems that keep these species out. We’re talking
invasive wasps. We’re talking all sorts of species of ants, mosquitoes.

MA: And the mosquitoes, we’ve read, are bringing all kinds of viruses with them.

JB: The risk with many of these mosquito species, to us, is disease. Think dengue fever,
think malaria. It’s still one of the global killers around the world. And as these species move
around, so do the diseases they transmit. And the same thing is happening for many of our
crop species, a big concern in New Zealand is Brown Marmorated Stink Bug.

JB: We absolutely know we don’t want that in New Zealand, it would attack many of our
crops, potentially attack many of our native plant species and transmit disease. Let’s keep it
out.

MA: So any other that you can think of, Al, that we should be aware of both here and abroad,
like what are the invasive species most concerning? I know one of the others is Caulerpa. We
talked about Caulerpa, which is actually, globally, a problem, it’s not just here. What else are
you finding that we’re having to deal with either here or, you’re from Australia, right?

AG: That’s right, New Zealand and Australia have some problems in common and a few key
differences as well. For example, one of the most damaging invasive predators in Australia is
the Red Fox. And, fortunately, foxes never established in New Zealand. It would have been a
real catastrophe if they had.

MA: How did they get there?

AG: Foxes were deliberately introduced to Australia by Europeans who wanted to pursue the
traditional English aristocratic sport of fox hunting on horseback. That was the reason, as
frivolous as that sounds, and it’s been an ecological catastrophe. Foxes have contributed to
the extinction of more than 20 native mammal species in Australia, and there are many other
species that will go extinct if we don’t continue to control foxes there.

AG: And it’s been a similar story here in New Zealand with the introduced stoats.
Fortunately, stoats never established in Australia, but they did here in New Zealand. And it’s
very striking that the native species that we’re left with here in New Zealand are the species
that are too big for a stoat to kill, whereas in Australia they have this sort of opposite situation
where the species that have not declined or become extinct are the ones that are too small for
foxes to bother with. So, if both invasive predators had been introduced to both countries, there’d be almost nothing left.

MA: So the other big issue that the UN report talked about was how expensive it is to deal
with the invasive species crisis. The number was something like $400 billion. And Al I heard
you say that maybe that was an underestimate. What are we talking about? Why are invasive species costing us?

AG: The report itself said that that $400-odd billion was a conservative estimate. I have read
a previous estimate that put the figure at well over a trillion dollars per annum. And to put
that in perspective, that’s about 5% of the global economy. It’s a staggering figure and it was
also estimated that that amounted to more than the combined costs of all the natural disasters around the world each year.

AG: So you think of the costs of earthquakes, cyclones, tsunamis, wildfires, add them all
together and they still don’t amount to as much economic cost as invasive species.

MA: Well, I imagine that’s partly because the invasive species are part of the natural, so-
called natural, I think we should start calling them unnatural disasters, frankly. But for
example, I understand that the reason that the fires in Hawaii were so fast and so rapid and so
devastating was because of an invasive species of grass that was highly flammable. I think
similarly, the fires in Canada had an element of the invasive species that were highly flammable. I imagine that that’s part of the calculation.

JB: And I think it’s a really important point that a lot of these drivers are interacting. As
climate warms and we’re getting these more extreme weather events, if you add into the fact that you’ve made your forests more flammable with some of these invasive species, often they seem to be flammable species, then you’ve got the two things interacting and then you go, oh my goodness, like where do you start with some of these things.

JB: And New Zealand’s not exempt to that. Many of our exotic species are highly flammable.
The pines, the hakea.

MA: Why do we have pines?

JB: Well, the pines form an incredibly important forestry resource in New Zealand. There’s
all sorts of economic drivers to that industry. But there are also other species that are not
economic that have come in, thinking of the Pinus contorta that’s got away in parts of New
Zealand. Sometimes it’s a mixture of things coming together there.

JB: But certainly, one of the things that I try not to lose sleep over is these interaction of
effects, because it just seems to be escalating all the time.

AG: And there’s a vicious circle there with fire and invasive pines as well. Pine trees are very
good at re-establishing very rapidly after wildfires. Often, whereas a lot of the native
vegetation will be destroyed and recover very slowly, pine trees will sprout up very quickly
after fire. I’ve seen photographs of recently burnt areas where there’s just a green carpet on
the forest floor, which is all just tiny baby pine seedlings, and there’s nothing else left.

AG: So, after repeated cycles of fire, we end up with native vegetation communities just
being completely replaced by a monoculture of pine trees.

MA: Why is it important that certain geographies have certain species and other geographies
not have them?

JB: Well, I think it speaks to the unique character of each place. I think there’s huge cultural
significance, but also, it’s talking as if all species are equal. But what’s happening with many
of these invasive species, it’s the same suite of species that are invasive around the world.
Sure, we could allow the world to become totally dominated by a handful of these species
that do well virtually everywhere.

JB: But then, we’ve just lost the richness. And just because those invasive species do really
well in certain circumstances at the moment, you lose that diversity from the world. Like if
conditions change in other ways, there’s no coming back. You’ve lost the continuity.

MA: If it is more resilient, to use an insect analogy, is it like a cockroach?

JB: Yeah. Coming back to the red imported fire ants that you mentioned before. That’s one of
the species that just seems to be expanding globally. And some countries have spent massive
amounts of money. Australia spent millions of dollars trying to get rid of it when they first
detected it in Brisbane and they failed, they could not do it. We were lucky. Red imported fire has been detected here and established a number of times. But we caught those incursions really early on, and with really concerted work and some clever effort, we eradicated. We, as far as I know, we’re the only place in the world that have achieved that. So when I heard this week that red imported fire ants have been detected established in Sicily, unless they are right onto it, we’re going to have red imported fire ants throughout Europe, which increases our risk. Every time these things spread to another locality, it just increases their ability to keep spreading further and further.

AG: Another reason that the loss of native species is so disastrous is that communities of
plants and animals and all living things have evolved together in their particular regions of
the world. And there are interactions that occur between these species that prop up entire
ecosystems. Obvious examples are things like plants that have specialist pollinators or
specialist seed dispersers.

AG: And often even if the pollinator or seed disperser doesn’t become extinct, it might just
become rare and just patchily distributed. So, you have a serious loss of ecological function
there. And one example of that here in New Zealand is the kererū, which of course is not
extinct. But they’re a lot less common and widespread than they used to be. And they’re
important spreaders of seeds for many native plants.

AG: The kererū is the New Zealand wood pigeon.

MA: The wood pigeon, the green and white. Gorgeous things. And are they in decline here now?

AG: I think their numbers are relatively stable now, but they’re much less common and widespread than they were in pre-European times.

MA: And do we know what’s causing that decline?

AG: A combination of factors. Definitely mammalian predators are implicated in their
decline, but also change in land use. They are a species that really likes the native bush.
Although having said that, there are parts of Auckland where they’re doing quite well, but
often anchored around things like pūriri that flower and produce fruit year-round. They are an
iconic New Zealand species that have definitely, it’s one of the many species that the invasive
species have played a significant role in reducing their numbers.

MA: You mentioned earlier about the interaction of all the drivers like climate and pollution
and land use and all of these things. I’m wondering if, in fact, ecosystems themselves, or the
species within the ecosystems, are going to have to move as a result of some of these anyway.
For example, some species can no longer live in the Gulf of Mexico because the water is just
too hot. So, they’re moving.

MA: And what does that mean overall for those becoming potentially introduced, potentially
invasive? And that interaction with climate and all of those matters.

JB: Incredibly challenging to try and figure that out, and many species around the world are
on the move already. It’s been documented for many, many, many species that they’re having
to shift into cooler climates, either by going north or south or by going up mountains or
elsewhere. Some species can move relatively easy. Others, we’ve lost that habitat connectivity.

JB: So, if you’re a bird and you need to get further north and there’s no habitat for you in
between, well, bad luck. There’s all those issues. But everything’s up in the air as to where it’s
all going to land because what do we do with a species that can’t shift on its own?

JB: Do we deliberately move it? And if we’re going to do that, do we take all the things that
it needs to form a community in the interactions with it? And where are we moving it to?
What happens to the species there?

MA: I know that’s happening.

AG: And there’s a risk that it could become an invasive species in the location that we
translocate it to.

MA: That’s exactly what I was getting at, because I do know they are moving some species
intentionally because they can’t survive anymore in those environments where they had lived.
I think there was a deer, a particular deer in the United States. They’re talking about moving it
because it can’t survive anymore. But then does it become invasive to another habitat?

AG: So hopefully in those cases they are doing their homework before they translocate these
species. And we can, if we’re careful, be pretty confident that an introduced species will not
become harmful. And there are some good examples here in New Zealand of species that
have been deliberately introduced as biological control agents for weeds. One is the heather beetle, and one is ragwort flea beetle.

AG: Both of these have been successful weed control, biocontrol agents. But before they
were brought here, there was very careful research carried out to ensure that these species
weren’t going to just start eating the native plants or competing with native invertebrates or
having any other sort of potentially harmful effect.

MA: I imagine the introduced honeybee has created problems for the indigenous New
Zealand bees.

JB: Yes, around the world there are issues around honeybees, but it’s one of the trade-offs
that humans get to make is like, we value the honeybee for all sorts of other reasons. And
that’s being traded off against potential impacts when we start having to manipulate these
things at the massive scale and speed with which we’re going to have to act with some of
these things. The sort of careful work that Al’s been talking about that happens around
bringing in biological control agents. I’m not sure that we’re going to have time to do that for
all these species.

AG: It takes years.

JB: It takes years. And then what do you do if, say, we discover that we need to shift an
iconic species somewhere else, and the answer is yes, it will have an impact on the receiving.
Do we then go, all right, we make the call that we’re happy to live with that or let the other
species go extinct? These are going to be tricky questions.

MA: I imagine here where we are in Aotearoa New Zealand, we’re surrounded by a big moat.
And so the controls on land, at least, are a little bit easier, certainly not the ocean, because we
share that with so many others. But how much do you feel like that has helped in the
protection of Aotearoa New Zealand’s biodiversity?

AG: Well, I think it’s been both a blessing and a curse, there’s no doubt that it has slowed the
ingress of exotic species into New Zealand in modern times. But it’s also that isolation which
has made New Zealand’s native species and native ecosystems so exquisitely vulnerable. So,
when invaders do arrive, our native species have no defence.

JB: That’s a really good point. But I think having that big moat, as you describe it, we can
play that to our advantage. And that’s perhaps one of the reasons why biosecurity is so strong
in New Zealand compared to the rest of the world, is that we have that natural advantage.

MA: And the fragility that comes with it.

JB: Yes. we’ve been able to build a system where, and we’re so lucky that we’re in New Zealand as one country and we’re not having to argue with all our neighbours about, we can decide as a nation how we move forward. That’s been an advantage as well. I think the other advantage New Zealand has is the latitudinal spread that we have.

JB: So when we’re talking about biota having to shift in response to climate change, we have
the ability for that to happen to some extent. It won’t solve everything, but that helps.

MA: You just used, for the first time in this conversation, the term biosecurity. How is that
different from biodiversity?

JB: Well, biosecurity describes all the activities that we do in relation to trying to keep
invasive species out and manage them if they do get in. It spans from pre-border to border to
post-border to long-term management if things get away. We use that term biosecurity but
interestingly, there’s a huge focus on it in New Zealand and Australia.

JB: But if you go to the other parts of the world and you start saying biosecurity, they think
we’re running around trying to keep weapons out or something.

MA: I could see that. Well, I’ve certainly never entered another country in which you have to
clean your shoes to come in, for example, to make sure there are no species on your shoe that could harm the fragile environment here.

AG: No, that’s right. But that’s not because New Zealand is being paranoid. It’s because we
have a very different situation, because we have been isolated for millions of years. There are
so many species of plants and fungi and micro-organisms that just don’t exist here. And
keeping them out is really important because they could cause catastrophic damage, whereas
in most other parts of the world these things are already present.

AG: So there’s no point trying to keep something out that’s already there.

JB: To some extent. Although there are places like Hawai’i which would love more stringent
biosecurity measures, but they are treated just as part of the mainland United States and so
they have new things arriving all the time. Their biota is equally as fragile as New Zealand
and they do not have the policies and regulations to try and stem that tide of things coming in.

JB: So our biosecurity colleagues in Hawai’i are very envious of New Zealand’s situation.

MA: That actually brings us to how I’d like to conclude our conversation, which is about
ways in which we can have interventions that are successful, and New Zealand has been very
successful in many ways, right? Are there lessons learned here that could be exported to help
others, but are there also lessons learned elsewhere that can be traded? What are the big interventions that you feel like we need here and abroad?

JB: Well, I think the UN report really highlights that as one of the key messages coming out,
is that we have to hold hands globally and make this work, and there’s no need for every
country to reinvent the wheel here. Around the world there are learnings. And if we can work
together on this, well, we need to work together because of the issue of globalization, but also
like, why wouldn’t you build on what other people are doing?

JB: And this is used all the time in many places. We share new import standards with
Australia for some species that go, okay, let’s just make sure our regulations mesh together
and make sense to the shipping companies so that we can reduce the risk of importing X, Y,
Z, brown marmorated stink bug as used in the report as an example.

JB: So let’s make sure that whatever we do in New Zealand aligns with Australia and
actually, why don’t we get all the other countries that don’t want brown marmorated stink bug
to jump onboard.

MA: Well I imagine our Pacific community would be among them.

AG: And actually, there’s huge benefits to Australia and New Zealand of sharing that
expertise with our neighbours, because if it establishes there it’s far more likely it’s going to
come here. And also, they have other ways of thinking and doing which would help improve our practice as well.

AG: Absolutely agree. And one of the other things that the new report emphasizes is that
preventing invasive species from arriving and establishing in the first place is far more cost
effective than dealing with them once they have arrived and become established. I would
urge people to cooperate with New Zealand’s biosecurity precautions, I know people might
regard it as a bit of an inconvenience at the airport. When you have to declare any foodstuffs
you’re bringing in and show them your hiking boots.

AG: But just remember that that is an absolutely essential thing, which is protecting us from
potentially billions of dollars’ worth of damage from invasive species. It’s really important to
prevent more invasive species from arriving.

MA: Are these practices that other countries should be considering? The kind of heightened
attention to visitors, shipments and other related entrances.

JB: Yes, and what to do when you get an incursion. I really hope that the Italians are looking
very closely at red imported fire ants right now and going, how do we contain it? What are
the learnings from Brisbane that didn’t manage to eradicate versus New Zealand where they
did, versus other places, etc. If we can focus in and stop some of these things spreading
before they become widespread.

JB: I mean Al and I have both had careers trying to deal with things once they’ve got here. I
would love it if we’d managed to keep social wasps out of New Zealand and there’s plenty of
other work for me, believe me. I would have been very happy not to have had to deal with
that one.

MA: So did those come in on their own or did those also come in with people?

JB: They came in accidentally. We know exactly when the German wasp arrived, at the end
of the Second World War on aircraft parts that were being shipped around. We knew exactly
when. We knew exactly where. And we did not have the tools to control it. If it had happened
now, we’d know exactly what to do and we probably could have achieved eradication.

JB: The next species of social wasp to arrive, the common wasp, we don’t even know how it
got here or exactly when. This is part of the whole puzzle of surveillance, monitoring. And
again, that’s where people in New Zealand can help. They are the eyes and ears out there. If
they see something that is unusual, contact MPI.

JB: There’s an 0800 number and a lot of the newly detected species in New Zealand have
been detected early because of exactly that. Members of the public have notified MPI.
MA: I’ve heard there’s an invasive species of Americans in New Zealand. What are the other kind of interventions that need to happen here and abroad?

AG: Well, in some cases, it is actually possible to eradicate invasive species.

MA: Is that desirable?

AG: Absolutely, where it is feasible, it’s desirable. And this is usually the case on islands
because you have a relatively limited size area. And also obviously being an island, much
reduced risk of re-invasion from outside, you’re not constantly trying to keep up with an
influx of new invaders. And New Zealand has led the world in this and we’ve been successful
in eradicating invasive species from many of our offshore islands around the country, which
has really secured the existence of many of our native species.

AG: And anyone who’s ever visited Tiritiri Matangi, just off the Auckland coast, will have
seen the benefits there where, even before the ferry docks on the island you can hear the
birdsong and when you get off you have birds just flying around your head, practically in
swarms, that you cannot see on the mainland. Species like tīeke, saddleback, which are
extinct on the mainland, apart from in fenced eco-sanctuaries, are so common on Tiritiri
Matangi that you see one every few moments and it just gives you an idea of what can be achieved in the absence of invasive predators.

MA: I suppose with invasive plants or flora, like if they would have eradicated the grass that
was in Hawaii, they might not have had such a destruction. So, that’s another thing. But then
how do you prevent that? I mean, it’s not like you can actually, I don’t know, maybe you can
see when it’s getting into the soil.

JB: You mean the plant itself? Sure. Well there’s, I mean, we mostly talk animals because
that’s our area of expertise, but there’s an equivalent amount of work being done on plants.
And there’s all sorts of strategies for dealing with the plants. But again, it’s the same thing in
that once they become widespread, they just about become intractable. And then you’re
talking about long term management, once things are really widespread in the landscape.

MA: So you just can’t let them get established.

JB: No, and it’s the early detection which requires surveillance, reporting and action. That’s
your main window of opportunity.

MA: In one of your recent publications, Jacqueline, you talked about how important
technology is now to do that surveillance. Is that already available or is that something that is
necessary to upgrade?

JB: Well, it’s rapidly developing. And there’s a lot of focus on new molecular tools. And I
think things like the global COVID pandemic showed the value of being able to use some of
these new molecular tools, the screening of wastewater so we could detect where it was
coming in. Those sorts of approaches can equally be applied to other species that we’re
concerned about getting in.

JB: So there is work all around the world looking at that sort of approach. But the other sort
of technology that’s rapidly increasing is machine learning and the ability for AI and these
things to help us out. And that’s obviously a rapidly escalating field, too. We don’t have to
keep doing the same things in the same way that often are hugely labour intensive and
difficult.

JB: I think we need to grasp these new technologies and look at how we can apply them to
make things more cost effective and effective.

MA: Al? Anything on the mitigation side of it? Policies, other technologies, what’s necessary
now, given the big, gigantic crisis that the UN just told us we have?

AG: So we’ve been focusing just now mainly on sort of early detection and eradication or
better still, prevention. But in many cases there are invasive species that have been present
already for decades, and they’re widespread, where eradication is not a realistic option. But
often there are still things that can be done, and those include containment, where we just
prevent the species from becoming any more widespread than it already is, and also just
managing invasive species in priority sites. For example, you might have an area where there are threatened native plants being out-competed by an invasive weed. So, you do weed control in those priority areas.

MA: Then I imagine, like you mentioned, the island Tiritiri Matangi, that there are
opportunities to restore like, an entire ecosystem, maybe minus the ones that went extinct.
But is there a lot of work going on in that area of restoration of ecosystems?

AG: Absolutely. Tiritiri Matangi is an excellent example. It was one of the first islands in
New Zealand to have invasive species eradicated, it happened during the eighties and
nineties. There’s been enough time now for the ecosystem to recover and many native bird
species were reintroduced there. But importantly, they also replanted the native vegetation.
Before restoration occurred, the island had been a sheep station and there was virtually no
native vegetation left, just pasture grass. But now the island is, I think, roughly 80% native vegetation.

MA: So it’s an example of what could be really done on a global scale. I mean minus the cities.
But as Jacqueline and I have talked, we could actually integrate cities into ecosystems and
connect them better.

JB: Sure. And I think one of the keys to the success on Tiritiri Matangi was the involvement
of community. Planting trees and restoring ecosystems is something that many, many people
in New Zealand get involved with. And it’s happening in cities, it’s happening on farms, it’s
happening out on our islands and natural environments. And I think if anything gives me
hope in New Zealand it’s just to see how, over the decades of my career, that whole activity’s
really taken hold in New Zealand. There’s a massive amount of community effort because these issues aren’t something that the government can solve on its own. We want people to get stuck in and many of them are leading now in that space.

MA: So it’s a potential model for restoration in other parts of the world.

JB: I think other parts of the world often look at what’s happening here and go, wow, that’s
cool. If we can harness that, well, there are other parts of the world where some of that
activity is happening. I’m not saying New Zealand is the only one, but again, we can learn
from each other as to what works better. Different ways of doing it.

MA: The goals that were set by the United Nations, are they adequate and doable or do they
need to up their game?

JB: I think a lot of those goals are aspirational. It’s probably a little bit like the climate
change goals for emissions that we set ourselves. Do they actually mean anything unless
there’s a concerted, genuine effort to make these things happen? And I think those are
political decisions, influenced by what we want as people. I think engaging with our
politicians to let them know what we want them to be investing time and effort into would be
a good way to help nudge that all in the right direction.

AG: Absolutely, and with an election coming up, our votes count.

JB: Get out and vote, people.