ScienceOctober 18, 2019

Could an uber-moose take over Fiordland?

Josie Adams

Contributing writer

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Ten moose were upended into the Dusky Sounds in 1910. Now, their descendants are getting their day in the sun.

The climate crisis is affecting wildlife all over the country: rockhopper penguin populations are in drastic decline, tuatara eggs aren’t hatching females, and the ice walls keeping predators away from kea are melting.

But it’s not all bad news: the largest animal in Fiordland has the smallest population, but the most chance of surviving the climate crisis. That’s right, the moose boom is coming.

The glacial hills of Fiordland aren’t much like the forests and tundras of Saskatchewan, and it’s long been debated that it’s an inappropriate place for moose. “The climate down there isn’t suitable for moose,” said Blake Cole, an experienced huntsman and a regular on the Fiordland tracks. Luckily for hunters like Cole, that’s about to change. The changing climate is accelerating and, maybe, moose evolution is too.

Moose were released into Fiordland because it’s the wettest part of New Zealand, and a significant portion of the moose diet is aquatic vegetation. They like to munch on your standard leaves and bark – young or disturbed forests are prime moose fodder – but they also bloody love a swamp lettuce. Usually, they eat the swamps bare in one season and go back to nibbling on bushes for the next.

The climate crisis – or climate Christmas for some lucky ungulates – is offering aquatic veg the chance to branch out. “Rapid change supports rapidly breeding species that humans usually consider invasive,” said botanist and natives keeper Sam Willyams. “Watercress is both invasive and edible.” Watercress grows commonly in New Zealand, where it enjoys growing in cool streams; like the edges of a southern fiord, or an alpine river. It’s already present in Fiordland, but hasn’t taken over the National Park the moose live in.

NIWA predicts Fiordland will see the highest increase in rainfall in New Zealand as the climate changes. Already, rain falls at least 200 days a year in these misty hills. The glaciers are melting faster than snow can fall. There are about to be a few more fjords in Fiordland.

And that’s just how the moose like it. Moose, like other species of deer, can swim very well. They’re known to dive up to six metres for their lunch. When the weather gets too warm for their thick coats, they go for a swim to cool off.

A classic moose-friendly environment is a dense, tall forest with some disturbed areas – free from logging or fires – for easy nibbling, and dotted with ponds and streams for paddling and snacking.

Whether the Fiordland moose’s aquatic foraging abilities resemble their ancestors’ is unknown. This is because they’re inbred. There was a founding population of eight (ten were released but two were shot soon after), but species have come back from worse.

In New Zealand, we can turn to the black robin. In 1980, there were only five of these fluffy chaps. Now, 250 of them live in the Chatham Islands. Interestingly, they seem to have few negative effects despite having such an extreme population bottleneck.

Moose are not short-lived birds, and may not be as good at processing inbreeding. However, that’s not a huge problem yet. They’re known to maintain low population densities. They’re very big and they eat a lot, but they rarely deplete their resources. They also avoid inbreeding as long as possible, so the eight moose who survived likely built as varied a gene pool as possible in their first couple of generations of breeding.

This means the Fiordland moose are probably only slightly inbred and are still capable of diving into glacial pools to pig out.

In 1985, the Norwegian island of Vega was colonised by three splash-happy moose. By 1992, the population was up to 24, including four fresh immigrants in 1991. The effects of inbreeding on the population were a slower birth rate and smaller babies. Small calves are less likely to survive predator attacks and cold weather.

The moose has no natural predators in New Zealand, except the lawless huntsmen and gold miners who sneak around the fjords in the dead of night. The weather is only getting warmer. There is no pressure on their population save their own cautious instincts. Given their low population, is it possible they could be a protected species? “I think the Conservation Act specifically deals with New Zealand native species,” said Fiordland Department of Conservation spokesperson Jamie McAulay.

Is it a pest, then? “It certainly isn’t at a high enough density to be causing problems.”

Well, not yet. Fiordland is getting warmer and wetter but will never be unbearably hot for a moose. There isn’t as much bark and pine for them to eat, but there are waterways and scrub full of tasty leaves.

Thanks to climate change, Kiwi moose hunters like Ken Tustin may soon be seeing the waterworld version of a moose: smaller, bolder, and more aquatic. Whether they’ll prove a danger to humankind is yet to be seen.

Polystyrene is a significant contributor to ocean plastic (Getty Images)

ScienceOctober 17, 2019

Cheat sheet: A call to arms on New Zealanders’ abuse of the ocean

Alex Braae

Staff Writer

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Polystyrene is a significant contributor to ocean plastic (Getty Images)

The actions of New Zealanders on land are increasingly harming the ocean’s ability to sustain life. Alex Braae looks at a worrying new government paper on the marine environment.

What’s all this then?

A new report from the Ministry for the Environment and Stats NZ has sounded alarming warning about state of the massive area of ocean around New Zealand. We’re currently putting whole ecosystems at risk of being killed off, and what’s more we don’t know how close we’re coming to doing just that, or even if it’s too late to save some species.

Dr Matt Pinkerton, a marine ecologist at NIWA, said what jumped out at him from the report was “the lack of adequate information on most issues affecting our marine environment, and the fact that different pressures interact and can reinforce each other creating complex threats.” He said the report should be “a call to arms to New Zealand”.

That sounds bad.

It is bad. And it’s our fault – we can’t put the blame elsewhere. We’re pumping huge amounts of sediment, chemical pollution and plastic directly into the ocean, says the report. While ocean ecosystems are highly complex, there’s one simple truth about them that we’re proving – they have a weakness for avalanches of crap being poured on them. As a result, the vast majority of seabirds and shorebird species are at some risk of extinction, as well as around one in five marine species.

And what about what we’re actually doing on the water?

We’re doing less seabed trawling than we used to, which is good, because it basically murders everything in its path. But it’s not none, and many fisheries remain under pressure. As well as that, a huge amount of material ends up in the sea as a result of both fishing and the logistics of moving stuff in and out of an island nation – that means more plastic especially.

So it’s bad for the seabirds and ocean creatures. Why does it matter to us?

The oceans sustain our ability to live on land as well, in all sorts of ways. Kaimoana is the obvious and immediate one. But on a deeper level, the oceans act as a massive carbon sink, which is at the moment protecting us from our own worst excesses with emissions. But there’s no telling how long that will continue to be the case, because they simply can’t keep absorbing carbon forever. They’re also becoming both warmer and more acidic, which is heightening the risks to marine life, along with your chances of having fish and chips in the future.

An orca off the east coast of New Zealand. Photo: Getty

The Ōhiwa Harbour kuku (green lipped mussel) population gives an alarming example of the effect we’re having on the marine environment. There were more than 100 million in 2007. Now there’s fewer than 500,000. There’s not one reason why they’re in such dramatic decline, but a combination of factors including sediment, plastic and toxin ingestion, habitat destruction generally and increasing pressure from climate change have all added up.

Who’s doing something about this?

Many are aware of the problem, and are taking steps to improve their areas. Dr Karen Fisher, an ecosystem-based management practices expert, had this to say: “The good news is that there are collaborations happening between central government agencies, local and regional councils, iwi, industry and community groups to tackle this, but I worry about the pace of change – time is of the essence.”

Is there anything we individuals can do about it?

On a simple level, stop dropping your damn durrie butts in the drain. Cigarettes alone contribute to a noticeable share of litter that washes up on beaches. But think of that as just a tiny microcosm of the wider impacts we need to curb. As Professor Mary Sewell from the University of Auckland put it, “start thinking about what you are leaving for future generations when you make decisions today.”

The way we treat the ocean is abominable, and will come back to haunt us. Individual people taking much more care won’t hurt, but for action to be successful it will need to be systemic, rigorous and coordinated. As an individual, you could ask whether you’re doing enough to keep the pressure on business and politicians to make that happen.