Humans are encroaching on Antarctica’s last wild places, threatening its fragile biodiversity



SL Chown, CC BY-NC

Rachel Leihy, Monash University and Steven Chown, Monash University

Since Western explorers discovered Antarctica 200 years ago, human activity has been increasing. Now, more than 30 countries operate scientific stations in Antarctica, more than 50,000 tourists visit each year, and new infrastructure continues to be developed to meet this rising demand.

Determining if our activities have compromised Antarctica’s wilderness has, however, remained difficult.

Our study, published today in Nature, seeks to change that. Using a new “ecological informatics” approach, we’ve drawn together every available recorded visit by humans to the continent, over its 200 year history.

We found human activity across Antarctica has been extensive, especially in the ice-free and coastal areas, but that’s where most biodiversity is found. This means wilderness areas – parts of the continent largely untouched by human activity – do not capture many of the continent’s important biodiversity sites.

Historical and contemporary human activity on Deception Island.
SL Chown

One of the world’s largest intact wildernesses

So just how large is the Antarctic wilderness? For the first time, our study calculated this area and how much biodiversity it captures. And, like all good questions, the answer is “that depends”.

If we think of Antarctica in the same way as every other continent, then the whole of Antarctica is a wilderness. It has no farms, no cities, no suburbs, no malls, no factories. And for a continent so large, it has very few people.

Antarctica’s wilderness should be held to a higher standard.
SL Chown

But Antarctica is too different to compare to other continents – it should be held to a higher standard. And so we define “wilderness” as the areas that aren’t highly impacted by people. This would exclude, for example, tourist areas and scientific stations. And under this definition, the wilderness area is still large.

It’s about 13,598,148 square kilometres, or more than 99% of the continent. Only the wilderness in the vast forested areas of the far Northern Hemisphere is larger. Roughly, this area is nearly twice the size of Australia.




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On the other hand, the inviolate areas (places free from human interference) that the Antarctic Treaty Parties are obliged to identify and protect are dwindling rapidly.

Our analyses suggest less than 32% of the continent includes large, unvisited areas. And even that’s an overestimate. Not all visits have been recorded, and several new traverses – crossing large tracts of unvisited areas – are being planned.

Human activity has been extensive across Antarctica, but large areas with no visitation record might still exist across central parts of the continent.
Leihy et al. 2020 Nature

Wilderness areas have poor biodiversity value

If so much of the continent remains “wild”, how much of Antarctica’s biodiversity lives within these areas?

Surprisingly few sites considered really important for Antarctic biodiversity are represented in the “un-impacted” wilderness area.

For example, only 16% of the continent’s Important Bird Areas (areas identified internationally as critical for bird conservation) are located in wilderness areas. And only 25% of protected areas established for their species or ecosystem value, and less than 7% of sites with recorded species, are in wilderness areas.

This outcome is surprising because wilderness areas elsewhere, like the Amazon rainforest, are typically valued as crucial habitat for biodiversity.

Ice-free areas are critical habitat for Antarctic biodiversity, like Adélie penguins, and frequently visited by people as well.
SL Chown

Inviolate areas have seemingly even less biodiversity value. This is because people have mostly had to visit Antarctic sites to collect species data.

In the future, remote sensing technologies might allow us to investigate and monitor pristine areas without setting foot in them. But for now, most of our knowledge of Antarctic species comes from places that have been impacted to some extent by people.

How does human activity threaten Antarctic biodiversity?

Antarctica’s remaining wilderness areas need urgent protection from increasing human activity.

Even passing human disturbance can impact the biodiversity and wilderness value of sites. For example, sensitive vegetation and soil communities can take years to recover from trampling.

Increasing movement around the continent also increases the risk people will transfer species between isolated regions, or introduce new alien species to Antarctica.

Expanding the existing network of Antarctic protected areas can secure remaining wilderness areas into the future.
SL Chown

So how can we protect it?

Protecting the Antarctic wilderness could be achieved by expanding the existing Antarctic Specially Protected Areas network to include more wilderness and inviolate areas where policymakers would limit human activity.

When planning how we’ll use Antarctica in the future, we could also consider the trade off between the benefits of science and tourism activities, and the value of retaining pristine wilderness and inviolate areas.




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This could be done explicitly through the environmental impact assessments required for activities in the region. Currently, impacts on the wilderness value of sites are rarely considered.

We have an opportunity in Antarctica to protect some of the world’s most intact and undisturbed environments, and prevent further erosion of Antarctica’s remarkable wilderness value.The Conversation

Ross Sea Region, Antarctica. Few sites considered really important for Antarctic biodiversity are represented in the wilderness area.
SL Chown

Rachel Leihy, PhD candidate, Monash University and Steven Chown, Professor of Biological Sciences, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate explained: what if we took all farm animals off the land and planted crops and trees instead?



Kira Volkov/Shutterstock

Sebastian Leuzinger, Auckland University of Technology


CC BY-ND

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz


I would like to know how much difference we could make to our commitment under the Paris Agreement and our total greenhouse gas emissions if we removed all cows and sheep from the country and grew plants in their place (hemp, wheat, oats etc). Surely we could easily become carbon neutral if we removed all livestock? How much more oxygen would be produced from plants growing instead? How would this offset our emissions? And what if we returned the land the animals were on to native forests or even pine plantations?

This is an interesting question and gives me the opportunity for some nice – albeit partly unrealistic – model calculations. Before I start, just two comments regarding the question itself.

Oxygen concentrations have been relatively stable at around 21% of the air we breathe for millions of years. This will not change markedly even if carbon dioxide emissions increase for years to come. Carbon dioxide concentrations, even in the most pessimistic emissions scenarios, will only get to around 0.1% of the atmosphere, hardly affecting the air’s oxygen content.

Secondly, grazing animals like cows and sheep emit methane — and that’s what harms the climate, not the grassland itself. Hemp or wheat plantations would have a similar capacity to take up carbon dioxide as grassland. But growing trees is what makes the difference.




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Here’s a back-of-the-envelope calculation to work out how New Zealand’s carbon balance would change if all livestock were removed and all agricultural land converted to forest.

If New Zealand stopped farming cows and sheep, it would remove methane emissions.
Heath Johnson/Shutterstock

Converting pasture to trees

This would remove all methane emissions from grazing animals (about 40 megatonnes of carbon dioxide equivalent per year).

New Zealand has about 10 million hectares of grassland. Let us assume that mature native bush or mature pine forests store the equivalent of roughly 1,000 tonnes of carbon dioxide per hectare.

If it takes 250 years to grow mature native forests on all former agricultural land, this would lock away 10 billion tonnes of carbon dioxide within that time span, offsetting our carbon dioxide emissions (energy, waste and other smaller sources) during the 250 years of regrowth. Because pine forest grows faster, we would overcompensate for our emissions until the forest matures (allow 50 years for this), creating a net carbon sink.

Note these calculations are based on extremely crude assumptions, such as linear growth, absence of fire and other disturbances, constant emissions (our population will increase, and so will emissions), ignorance of soil processes, and many more.

If agricultural land was used to grow crops, we would save the 40 megatonnes of carbon dioxide equivalent emitted by livestock in the form of methane, but we would not store a substantial amount of carbon per hectare.




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Steps towards a carbon-neutral New Zealand

How should we interpret this rough estimate? First, we must acknowledge even with our best intentions, we still need to eat, and converting all agricultural land to forest would leave us importing food from overseas — certainly not great for the global carbon budget.

Second, it shows if livestock numbers were at least reduced, and we all turned to a more plant-based diet, we could reduce our emissions substantially. The effect would be similar to reforesting large parts of the country.

Third, this example also shows that eventually, be it after 250 years in the case of growing native forests, or after about 50 years in the case of pine forests, our net carbon emissions would be positive again. As the forests mature, carbon stores are gradually replenished and our emissions would no longer be compensated. Mature forests eventually become carbon neutral.

Even though the above calculations are coarse, this shows that a realistic (and quick) way to a carbon-neutral New Zealand will likely involve three steps: reduction of emissions (both in the agricultural and energy sectors), reforestation (both native bush and fast growing exotics), and a move to a more plant-based diet.The Conversation

Sebastian Leuzinger, Professor, Auckland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)



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Anthea Batsakis, The Conversation and Wes Mountain, The Conversation

This article is part of Flora, Fauna, Fire, a special project by The Conversation that tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Explore the project here and read more articles here.


Before the summer bushfires destroyed vast expanses of habitat, Australia was already in the midst of a biodiversity crisis. Now, some threatened species have been reduced to a handful of individuals – and extinctions are a real possibility.

The Kangaroo Island dunnart, a small marsupial, was listed as critically endangered before the bushfires. Then the inferno destroyed 95% of its habitat.

Prospects for the Banksia Montana mealybug are similarly grim. This flightless insect lives only on one species of critically endangered plant, at a high altitude national park in Western Australia. The fires destroyed 100% of the plant’s habitat.




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And fewer than 100 western ground parrots remained in the wild before last summer, on Western Australia’s south coast. Last summer’s fires destroyed 40% of its habitat.

Fish, crayfish and some frogs are also struggling. After the fires, heavy rain washed ash, fire retardants and dirt into waterways. This can clog and damage gills, and reduces the water’s oxygen levels. Some animals are thought to have suffocated.

Here, dozens of experts tell the stories of the 119 species most in need of help after our Black Summer.

How can I help?

Recovery from Australia’s bushfire catastrophe will be a long road. If you want to help, here are a few places to start.

Donate

Australian Wildlife Conservancy

Bush Heritage Australia

WWF

Birdlife Australia

Also see this list of registered bushfire charities

Volunteer

Parks Victoria

NSW National Parks and Wildlife Service

Queensland Parks and Wildlife Service

Conservation Volunteers Australia

Landcare

The Conversation

Anthea Batsakis, Deputy Editor: Environment + Energy, The Conversation and Wes Mountain, Multimedia Editor, The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Carbon pricing works: the largest-ever study puts it beyond doubt



Shutterstock/ANU

Paul Burke, Crawford School of Public Policy, Australian National University; Frank Jotzo, Australian National University, and Rohan Best, Macquarie University

Putting a price on carbon should reduce emissions, because it makes dirty production processes more expensive than clean ones, right?

That’s the economic theory. Stated baldly, it’s obvious, but there is perhaps a tiny chance that what happens in practice might be something else.

In a newly-published paper, we set out the results of the largest-ever study of what happens to emissions from fuel combustion when they attract a charge.

We analysed data for 142 countries over more than two decades, 43 of which had a carbon price of some form by the end of the study period.




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The results show that countries with carbon prices on average have annual carbon dioxide emissions growth rates that are about two percentage points lower than countries without a carbon price, after taking many other factors into account.

By way of context, the average annual emissions growth rate for the 142 countries was about 2% per year.

This size of effect adds up to very large differences over time. It is often enough to make the difference between a country having a rising or a declining emissions trajectory.

Emissions tend to fall in countries with carbon prices

A quick look at the data gives a first clue.

The figure below shows countries that had a carbon price in 2007 as a black triangle, and countries that did not as a green circle.

On average, carbon dioxide emissions fell by 2% per year over 2007–2017 in countries with a carbon price in 2007 and increased by 3% per year in the others.


Carbon dioxide emissions growth in countries with and without a carbon price in 2007

Emissions are from fuel combustion and include road-sector emissions.
Best, Burke, Jotzo 2020

The difference between an increase of 3% per year and a decrease of 2% per year is five percentage points. Our study finds that about two percentage points of that are due to the carbon price, with the remainder due to other factors.

The challenge was pinning down the extent to which the change was due to the implementation of a carbon price and the extent to which it was due to a raft of other things happening at the same time, including improving technologies, population and economic growth, economic shocks, measures to support renewables and differences in fuel tax rates.

We controlled for a long list of other factors, including the use of other policy instruments.

The higher the price, the larger the emissions reductions.

It would be reasonable to expect a higher carbon price to have bigger effects, and this is indeed what we found.

On average an extra euro per tonne of carbon dioxide price is associated with a lowering in the annual emissions growth rate in the sectors it covers of about 0.3 percentage points.

Lessons for Australia

The message to governments is that carbon pricing almost certainly works, and typically to great effect.

While a well-designed approach to reducing emissions would include other complementary policies such as regulations in some sectors and support for low-carbon research and development, carbon pricing should ideally be the centrepiece of the effort.

Unfortunately, the politics of carbon pricing have been highly poisoned in Australia, despite it being popular in a number of countries with conservative governments including Britain and Germany. Even Australia’s Labor opposition seems to have given up.

Nevertheless, it should be remembered that Australia’s two-year experiment with carbon pricing delivered emissions reductions as the economy grew. It was working as designed.




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Groups such as the Business Council of Australia that welcomed the abolition of the carbon price back in 2014 are now calling for an effective climate policy with a price signal at its heart.

Carbon pricing elsewhere

The results of our study are highly relevant to many governments, especially those in industrialising and developing countries, that are weighing up their options.

The world’s top economics organisations including the International Monetary Fund, the World Bank and the Organisation for Economic Co-operation and Development continue to call for expanded use of carbon pricing.

If countries are keen on a low-carbon development model, the evidence suggests that putting an appropriate price on carbon is a very effective way of achieving it.


An open-access version of this research is available here.The Conversation

Paul Burke, Associate Professor, Crawford School of Public Policy, Australian National University; Frank Jotzo, Director, Centre for Climate and Energy Policy, Australian National University, and Rohan Best, Lecturer in Economics, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fire-ravaged Kangaroo Island is teeming with feral cats. It’s bad news for this little marsupial



AAP Image/Supplied by WWF-Australia

Rosemary Hohnen, Charles Darwin University and Sarah Legge, Australian National University

When I visited Kangaroo Island for the first time after the summer bushfires, I thought I knew what to expect. But what really hit me was the scale.

The wild western end of the island, once a vast mallee woodland peppered with wildflowers and mobs of roaming roos, had been completely erased. An immense dune field covered with sharp blackened sticks now stretched beyond the horizon, to the sea, hollow and quiet.

While fire is a fundamental process in many Australian ecosystems, the size and severity of this fire was extreme, and the impacts on the island’s wildlife has been immense.




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For the many threatened species on Kangaroo Island, such as the critically endangered Kangaroo Island dunnart, their fight for survival still isn’t over. High numbers of feral cats roaming the landscape now pose a huge threat to their persistence, with little vegetation left within the fire scar to provide cover for wildlife.

In fact, our recent research found there are, on average, almost double the number of cats per square kilometre on Kangaroo Island than on the mainland.

The scale of the fires

Kangaroo Island is uniquely positioned, home to wildlife native to both eastern and western Australia. It protects nationally threatened species, such as the glossy black-cockatoo, the pygmy copperhead, Rosenberg’s goanna and the Kangaroo Island dunnart.

The recent bushfires on Kangaroo Island were the largest ever recorded there, destroying swathes of habitat. Over a period of 49 days the fire burnt 211,255 hectares, impacting almost half of the island, particularly the western and central regions.

For the critically endangered Kangaroo Island dunnart, the fires burnt approximately 95% of the species’ known habitat and left them on the brink of extinction.

Dunnarts face extinction

The Kangaroo Island dunnart is a small carnivorous marsupial weighing about 20 grams, with soft sooty fur and dark eyes. The species eats mainly insects, and shelters in hollow logs and in the skirts of grass trees.

Even prior to the fire the species was considered likely to become extinct in the next 20 years. Despite extensive survey efforts, the dunnart had only been seen at 19 sites on Kangaroo Island between 1990 and 2019.

Our own survey work between 2017 and 2018 confirmed the persistence of the dunnart at just six sites in the national park, with Kangaroo Island Land for Wildlife detecting several additional records on private land. All sites were in the western half of the island where the recent fires burned.

Many dunnarts are likely to have died in the fire itself, but individuals that survived are left extremely vulnerable to starvation and feral cat predation.

Cats roaming the island in big numbers

Between two and six million feral cats are estimated to live in Australia, and collectively kill more than three billion animals per year.




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The problem is so large, a parliamentary inquiry is, for the first time in 30 years, investigating the impact of feral and domestic cats to native wildlife.

What’s more, in some areas on Kangaroo Island where the availability of animal carcasses is high, the density of feral cats is more than ten times as high as mainland estimates.

There are twice as many cats per square kilometre on Kangaroo Island than on mainland Australia.
Shutterstock

A high cat density poses a formidable threat to wildlife survival during the post-fire period, because cats will sometimes travel large distances to hunt within recent fire scars. Research is underway on the island to examine exactly how the fires have changed cat densities and hunting behaviour in and around burnt areas.

How to control feral cats

Controlling feral cats is one of the biggest challenges in Australian conservation. Cats are cryptic and cautious, hard to find, see, trap and remove.

Despite the challenge, a large-scale feral cat eradication is underway on Kangaroo Island. This is the largest island on which cat eradication has ever been attempted, and the project will take years.




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In the meantime, feral cats are being controlled around the last refuges for Kangaroo Island dunnarts. There are multiple methods for this including shooting and cage trapping, but in remote areas that are hard to access, poison-baiting is likely to be an effective, long-term strategy.

Most feral cat baits are meat-based, but our research shows possums and bush rats are still likely to consume them.

Therefore, researchers have worked for many years on strategies to minimise the potential impacts of feral cat baits on native wildlife. For example, the poison can be delivered within a hard plastic pellet, inside the meat bait.

Field trials have indicated that while cats swallow portions of this bait whole, ingesting the pellet, most native wildlife will chew around and discard the pellet.

Hope emerges after huge survey effort

Despite the gravity of the risk to Kangaroo Island wildlife, there is hope. A huge, dedicated and effective survey effort by both government and non-government organisations has resulted in the detection of Kangaroo Island dunnarts at more than 22 sites.

Kangaroo Island dunnarts have been spotted in devastated parts of the landscape.
Jody Gates, Author provided

These small populations have been found mostly within patches of unburnt vegetation, but also – almost unbelievably – in areas that have been completely burnt.




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Many of these populations appear to be very small and isolated. And now, more than ever, they’re extremely vulnerable. Targeted cat control and/or protection of vulnerable populations with exclusion fencing may be the only way to prevent their extinction.

By controlling cats, we can help native species like the Kangaroo Island dunnart get through this difficult time, and continue to fulfil their place in that wild landscape for years to come.


The authors would like to acknowledge and thank Paul Jennings, Pat Hodgens, Heidi Groffen, James Smith and Trish Mooney, for their generous contributions to this article.The Conversation

Rosemary Hohnen, Adjunct associate, Charles Darwin University and Sarah Legge, Professor, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.