Threshold

I flew to Hobart to pay my respects to an ecosystem already long gone. Tasmania’s giant kelp forests, Macrocystis pyrifera, once fringed the eastern coast. Each languid frond of these once-towering marine metropoles harboured multitudes of fish, invertebrates, plankton and algae. But giant kelp forests are fragile: they can only grow to depths of thirty metres, and they require cool waters with high nutrient levels, a rocky seafloor for their gnarled holdfasts to cling to. Tasmania is one of the few places worldwide with the ideal conditions for Macrocystis, along with New Zealand, the American continents and South Africa, but climate change has taken its toll. As of 2017, only five per cent of the original Tasmanian kelp forests remained.

The data on these kelp forests only dates back around thirty years. Everything else western science knows is anecdotal, from the mouths of fishers and divers, or from Aboriginal knowledge and customs. Aboriginal Tasmanians are perhaps some of the most culturally displaced Indigenous peoples on this planet, despite living on their own soil. The impacts of British genocide throughout the early 1800s are ongoing and have led to a great loss of connection to culture and knowledge. For the Aboriginal community in Tasmania, the sea is women’s business, and so their relationship with the kelp forests – and all the species that call the kelp home – is strong, and has played a central role in cultural recovery. But Aboriginal researcher Emma Lee is concerned that climate change could see much more of her peoples’ heritage lost to the warming seas.

Lee is a sunny and buoyant Trawlwulwuy woman from Tebrakunna country, in north-east Tasmania, who lives and works in Hobart. She is also an expert on Indigenous rights and land management, and is based at the University of Tasmania’s Centre for Marine Socioecology. She confesses her ‘force of personality’ is a deliberate strategy; she uses it to give Indigenous issues a sense of immediacy. It’s effective. I first met her at a petrol station just out of Hobart and she greeted me with an embrace that nearly knocked me over.

Moving

We agreed to take a drive to Opossum Bay, the location of an archaeological site that Lee visits. As she steered her way through the winding terrain Lee made sure I was up-to-date on the kelp-forest situation. Most Tasmanians can tell you how important the kelp has been for the shellfish and lobster industry, and I’d spent a few weeks with scientists at the Institute for Marine and Antarctic Studies before meeting Lee to get an idea of the empirical changes going on underwater. As it turns out, the Macrocystis forests have been totally replaced by urchin barrens: eerie submarine deserts formed by Centrostephanus rodgersii, better-known as the long-spined sea urchin.

These urchins haven’t always been part of Tasmanian marine life. Before 1978, there wasn’t an urchin to be seen, but since then, the very large crayfish and other predators that feast on juvenile urchins have fallen prey to Tasmania’s booming seafood industry, with only smaller crays left behind. This loss of large predators might not have affected Macrocystis’ if the urchin larvae hadn’t reached Tasmania in the first place. Water temperatures around Tasmania have typically fallen below the urchins’ twelve-degree minimum, but climate change since the mid-1980s has brought a southward shift in the Eastern Australian Current, meaning the cold winter waters essential for killing off urchin larvae, before they reach Tasmania, are no more. Hence the urchin boom.

The urchins are not an isolated case. Climate change is not as straightforward as extinction and apocalypse. The planet’s latitudinal climate bands are creeping gradually towards the poles, and species are trying to follow in their wake. When habitat-forming species like Macrocystis are subjected to such range shifts, the effects pervade throughout their entire ecosystem. In a southward migration, Tasmania is the last post for the giant kelp, and all the life it shelters. With no appropriate substrate further below, these giant kelp forests are, quite literally, falling off the face of the earth.

In situ

It was hard to imagine this submarine devastation when we arrived at the sparkling vista of Oppossum Bay. After a short walk along the beach we reached our destination: a living midden site, which appeared to me as a seaside build-up of billions of sun-bleached shells stretching right down to a rocky point in the water. The tides did not bring these shells here, though; people did.

Before us, Lee laid out the marineer shell necklaces unique to Aboriginal Tasmania, famous for their stunning blue-green iridescence. They’re also known as rainbow kelp shells, or Phasianotrochus irisodontes, and are found living in the deeper intertidal zones from the Bass Strait down the entire eastern coast of Tasmania. Below us, 6000 years’ worth of shell debris from Aboriginal people’s meals were layered to form the living midden, ‘living’ not only because middens change over time, from winds, erosion, and new layers, but because they are still used by Aboriginal people as pathways and markers, as meeting places. They are a living reminder of identity and place in country.

Lee’s marineer shell necklaces are from the kelp forests. So too are the layers of midden shells. The species that make up the middens may be long-dead, but their strata are a record of millennia of marine life and fishing practices.

‘In Tassie there’s anything up to about two dozen types of [shellfish] species,’ Lee said. ‘The majority of them of course are the larger species like abalone, crayfish, but also werriners, cat’s eyes, mussels, oysters, periwinkle, any big rocky platform species. There wasn’t too much we didn’t actually have a go at.’ She pointed out that Tasmania’s pre-colonial fisheries were far more diverse than the wild fisheries of today: the state earns $168 million each year from its rock lobster and abalone exports. The shells of species littered throughout Tasmania’s middens offer an extensive and well-preserved record of the historical shifts in shell size, abundance and diversity. The middens can tell us a lot about both the culture of Aboriginal Tasmanians and the ecosystems they steward, yet very little study has been done on the middens’ ecological value.

‘No scientist wants a relationship, they want data. Scientists have been told that they’re not allowed to be human or emotional… [they’ve] never been exposed to this as an element of particular citizen science, on how you can measure the rates of change, or the range shift,’ Lee said. ‘There’s so much information there that we really need to bring together.’

Researchers have been slow to pick up on just how much information these middens might store, in part because the information does not fit into the traditional methodology of western science. For instance, Lee sees their potential as indicators of climate change. Living middens, she pointed out, are not created to be underwater.

‘We actually have this amazing marker of climate change and sea level rise,’ she said. ‘All across Australia we’ve got these heritage registers of middens … When we’re talking about coastal, saltwater ones, we’ve got an in-built monitoring mechanism.’ And yet, she is worried that just at the point in time where scientists might recognise that a midden could be an invaluable marker of climate and species range shifts, they’ll be washed away by rising tides.

‘Two years ago I was down in the southwest, and middens that had been recorded there twenty years ago are completely gone. Not a sign, not a mark of them. They’ve been washed away,’ she said. Of course, the idea of digging up the middens for that information does not sit well with Lee. As an archaeologist, she hungers for their knowledge and worries about what will be lost if they are washed away by the ocean, but as an Aboriginal woman, she said to dissect them would feel like digging into her own skin.

The jewel-bright marineer necklaces are icons of the Tasmanian Aboriginal identity and the practice of stringing them is one of the few traditions uninterrupted by European colonisation. Collected and strung by Aboriginal women through their lifetime, each shell on a necklace must be the same size, with shells harvested live from the kelp beds. Lee’s collection includes necklaces she has strung herself, and a few she has inherited from women in her family.

‘Men and women wore them, but they are representative of women’s governance, because they are of the sea,’ Lee said. ‘These necklaces actually embody our sense of gender roles.’ When I asked Lee how she felt about the loss of the giant kelp forests, her usual effervescence went flat. A storm rolled across her face. She traced her fingers lightly along her arms, trying to think of a way to express her feelings without betraying women’s business to a whitefella like myself.

‘I fear for what we call our cultural keystone species … When part of my identity is connected to these middens, and they’re gone, how does that affect my identity as an indigenous person?’ she said. ‘I see those kelp forests like the arteries and veins in our bodies, our women’s bodies, and when those forests are gone, I know I’m going to feel that loss, within my own body.’

Weeds

Poleward-shifting species pose a tricky conservation question. Take, for instance, how we talk about invasive species: weeds, plants in the wrong place. A weed might have come from a place further north, and now it turns up on the shores of a foreign continent. Traditional conservation practice would lean towards removing the weed, lest it compete with native species and begin to cause environmental degradation. But under different climate conditions, ‘native’ species themselves may no longer be suited to the landscapes they evolved in.

And what we used to call weeds might now be the life best-suited to that environment, and our best chance at biodiversity. The invisible lines of national parks, countries and continents mean little when the climate itself can escape through them like a runaway ghost, enticing the species that have come to depend on it to follow the poleward path. Trying to restore a specific section of land to its supposedly ‘pristine’ state becomes a sisyphean task under these conditions.

Range shifts bring uncertainty to the very definition of endemism. Does a species retain its native status through measures of climate, or latitude? Nationality or suitability? Should we continue to religiously remove invasive species ‘in the wrong place’, even if they’re climate migrants? Or should we in fact be assisting their migration polewards, helping them keep up with their suited climate band? As an Indigenous person, Lee said she struggles to accommodate the old-school ‘fences and fines’ conservation approach, particularly where it conflates restoration with beauty and authenticity.

‘I despise that term wilderness … [it’s] an old Judeo-Christian term which means that the evil hasn’t been removed from a place yet … I think blacks were considered weeds once, to be removed from a pristine environment,’ Lee said. ‘Wilderness prevents people from having that relationship, that kinship with country … actually it’s a colonising technique. I believe in restoration, yes, of course … but don’t pretend we’re trying to create this pristine wilderness environment, because it never existed.’

Cope

In a future of climate change and species on the move, Lee believes Aboriginal Tasmanians will lose out twofold. Not only lose the kelp forests that their culture is so closely tied to, but their scope for cultural adoption of new species and new ecosystems will also be limited.

‘I regret and I rue the fact that native species are being lost, but for being lost, does that mean we shut the door for others?’ The warmer waters have brought some new species more desirable than urchins, including snapper and yellowtail kingfish. In 2016 an article in Hobart’s local paper The Mercury announced: ‘Warmer waters makes Tassie a hotspot for new fishy friends,’ reporting record catches of New South Wales table fish species.

‘We’re gonna come up against this thing of authenticity, because we won’t be allowed to adapt to new species, because that won’t be seen as being “black” enough,’ Lee said. ‘I think traditional knowledges are about managing change … The speed of it is something that Indigenous local peoples are grappling with, but we haven’t said it’s beyond us. We’ve all been through it. There’s not an Indigenous mob on the face of this earth that hasn’t gone through massive climate change.’

‘For instance, some of these New South Wales species with the range shifts might actually be okay for us,’ she continued. ‘There’s part of me that’s a bit excited because I know snapper is coming into Tasmanian water, and I love eating snapper … but that’d be held against me because it’s not authentic, it’s not the restoration game, the snapshot on the map is that I have to exist as something from 200 years ago.’

Lee jokes that maybe they’ll have to start stringing urchin necklaces, but beneath her laughter we both know it’s a cold comfort. Both kinds of shells – marineer and midden – make up an integral part of Aboriginal life in Tasmania, and have been crucial to the deep cultural recovery of these peoples who were subjected to the very worst of western colonial impacts. These traces of culture are what they have left, and it’s no small inheritance.

Over the next century Tasmanians – especially Indigenous Tasmanian women – will barely recognise their submarine landscapes, and they will feel this ripple through their cultural identity. Living midden sites will be washed away. The precious marineer shells will be harder to find. The process of cultural recovery among Aboriginal Tasmanians will be further hindered by weather, waves, species shifts, and other hallmarks of the Anthropocene. ‘I’m an optimist,’ Lee said, ‘My cup runneth over, and I genuinely believe the next generation will do so much better, all of them. That’s why I think my role is one of visibility, legitimacy.’

Tasmania gives us a glimpse into the future, but these peoples are not alone in their experience. Western colonisation is a haunting that started with genocide and continues with the Anthropocene. But however species migration manifests regionally, the ecological trauma of such a rapid change will be felt from the microbial plankton level right up to the sweating multicellular bodies of politicians in parliament and scientists in the lab. It will touch us all. We can only hope that by then, it is not too late to learn from the traces of climates and cultures past.

Image: Macrocystis pyrifera