Not declaring the Great Barrier Reef as ‘in danger’ only postpones the inevitable


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Jon C. Day, James Cook University; Scott F. Heron, James Cook University, and Terry Hughes, James Cook UniversityAfter much anticipation, the World Heritage Committee on Friday decided against listing the Great Barrier Reef as “in danger”.

The decision ignored the recommendation of the International Union for Conservation of Nature (IUCN) and the UNESCO World Heritage Centre — a recommendation based on analyses by Australian scientific experts of the reef’s declining condition.

In many ways, the outcome from the committee was expected. The Australian government fought very hard against this decision, including lobbying all the committee members, as it has done in previous years.

There was consensus among most of the 21 committee members to not apply the in-danger listing at this time. Instead, Australia has been requested to host a joint UNESCO/IUCN monitoring mission to the reef and provide an updated report by February, 2022.

This decision has only postponed the inevitable. It does not change the irrefutable evidence that dangerous impacts are already occurring on the Great Barrier Reef. Some, such as coral bleaching and death from marine heatwaves, will continue to accelerate.

The reef currently meets the criteria for in-danger listing. That’s unlikely to improve within the next 12 months.




Read more:
The Barrier Reef is not listed as in danger, but the threats remain


Political distractions

Last month, the World Heritage Committee released its draft decision to list the reef as in-danger, noting the values for which the reef was internationally recognised had declined due to a wide range of factors. This includes water pollution and coral bleaching.

The draft decision had expressed concerns that Australia’s progress:

has been largely insufficient in meeting key targets of the Reef 2050 Plan [and the] deterioration of the ecological processes underpinning the [Reef has] been more rapid and widespread than was previously evident.

A photo depicting two threats to the Great Barrier Reef: coal ships anchored near Abbot Point and a flood plume from the Burdekin River (February 2019); such plumes can carry pollutants and debris to the Great Barrier Reef.
Matt Curnock

In response, the government claimed it was “blindsided”, and said the UNESCO Secretariat hadn’t followed due process in recommending the decision. It also suggested there had been undue interference from China in making the draft recommendation.

These were political distractions from the real issues. During last night’s debate, one committee member strongly refuted the claims about interference from China and expressed concerns the dialogue had become unnecessarily politicised.

Following the draft decision, the intense campaign to reverse the decision began, with environment minister Sussan Ley undertaking a whirlwind visit to numerous countries to meet with ambassadors.




Read more:
The Great Barrier Reef is in trouble. There are a whopping 45 reasons why


The government even hosted international ambassadors from 13 countries and the EU, taking them on a snorkelling trip. And it reported an increase in coral cover over the past two years as good news, ignoring the fact the assessment had cautioned the recovery was driven by weedy coral species most vulnerable to future climate impacts.

This wasn’t the first time Australia has undertaken significant levels of diplomatic lobbying of World Heritage Committee members to gain support for its position.

In 1999, Australia also strongly opposed the recommended in-danger listing of Kakadu National Park, following the Jabiluka mine proposal. This led to an extraordinary meeting of the committee being convened in Paris, specifically to discuss this matter.

Turtle
Australia is expected to hand in an updated report on the reef in February 2022.
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More focus on climate change

During its current meeting, the World Heritage Committee approved the draft UNESCO Climate Action Policy, which will guide the protection and conservation of World Heritage sites.

This policy will be ratified at the UN General Assembly later this year, but the fact it’s still a draft was one of several excuses the Australian government made as to why the reef should not be “singled out”.

The reef is one of the most iconic marine protected areas on the planet. Given Australia continues to have one of the highest per capita emission rates in the world, and has more capacity to address climate change than most other countries, it makes sense for the spotlight to be on Australia’s actions.

Aerial photo of part of the reef
Marine heatwaves and water pollution are major threats to the Great Barrier Reef.
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Not surprisingly, climate change was the central issue during the committee’s debate last night. UNESCO is now more focused on climate change than ever before, recognising the “window of opportunity to act” is now.

The delegates broadly agreed climate change remains the most serious threat, not just to the Great Barrier Reef but also to many other iconic World Heritage properties. Venice, for example, also dodged a potential in-danger listing at this meeting.

Rather than making challenging decisions now, it’s clear the committee is simply kicking the can down the road.

Some committee members remarked during the meeting about the need to “maintain the credibility of the Convention” and acknowledged that the world is watching. The spotlight on the reef, and on Australia, will only intensify in coming years.

The government’s own report from 2019 shows many of the values for which the reef was inscribed on the World Heritage list in 1981 have declined in recent decades. Yet every delay weakens Australia’s claim it is doing all it can to protect the reef.

Later this year, the next major international climate summit will be held in Glasgow, Scotland, where even more attention will be placed on Australia’s inadequate actions.

An in-danger listing is not a punishment

It’s important to remember that throughout the meeting, UNESCO and the committee made it clear an in-danger listing is not a sanction or punishment. Rather, it’s a call to the international community that a World Heritage property is under threat, thereby triggering actions to protect it for future generations.




Read more:
Is Australia really doing enough for the Great Barrier Reef? Why criticisms of UNESCO’s ‘in danger’ recommendation don’t stack up


Now, more than ever, it is important to expand efforts to reduce the locally manageable impacts, such as poor water quality, while rapidly accelerating action on climate change.

These efforts must occur locally, nationally and globally. Reducing greenhouse gas emissions is critical to stop the worst of the impacts now unfolding, not just on the reef, but on all the world’s natural and cultural heritage.


This story is part of Oceans 21

Our series on the global ocean opened with five in-depth profiles. Look out for new articles on the state of our oceans in the lead up to the UN’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.The Conversation


Jon C. Day, PSM, Adjunct Senior Research Fellow, ARC Centre of Excellence for Coral Reef Studies, James Cook University; Scott F. Heron, Associate Professor, James Cook University, and Terry Hughes, Distinguished Professor, James Cook University

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

Wind turbines off the coast could help Australia become an energy superpower, research finds


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Sven Teske, University of Technology Sydney; Chris Briggs, University of Technology Sydney; Mark Hemer, CSIRO; Philip Marsh, University of Tasmania, and Rusty Langdon, University of Technology SydneyOffshore wind farms are an increasingly common sight overseas. But Australia has neglected the technology, despite the ample wind gusts buffeting much of our coastline.

New research released today confirms Australia’s offshore wind resources offer vast potential both for electricity generation and new jobs. In fact, wind conditions off southern Australia rival those in the North Sea, between Britain and Europe, where the offshore wind industry is well established.

More than ten offshore wind farms are currently proposed for Australia. If built, their combined capacity would be greater than all coal-fired power plants in the nation.

Offshore wind projects can provide a win-win-win for Australia: creating jobs for displaced fossil fuel workers, replacing energy supplies lost when coal plants close, and helping Australia become a renewable energy superpower.

offshore wind turbine from above
Australia’s potential for offshore wind rivals the North Sea’s.
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The time is now

Globally, offshore wind is booming. The United Kingdom plans to quadruple offshore wind capacity to 40 gigawatts (GW) by 2030 – enough to power every home in the nation. Other jurisdictions also have ambitious 2030 offshore wind targets including the European Union (60GW), the United States (30GW), South Korea (12GW) and Japan (10GW).

Australia’s coastal waters are relatively deep, which limits the scope to fix offshore wind turbines to the bottom of the ocean. This, combined with Australia’s ample onshore wind and solar energy resources, means offshore wind has been overlooked in Australia’s energy system planning.

But recent changes are producing new opportunities for Australia. The development of larger turbines has created economies of scale which reduce technology costs. And floating turbine foundations, which can operate in very deep waters, open access to more windy offshore locations.

More than ten offshore wind projects are proposed in Australia. Star of the South, to be built off Gippsland in Victoria, is the most advanced. Others include those off Western Australia, Tasmania and Victoria.

floating wind turbine
Floating wind turbines can operate in deep waters.
SAITEC

Our findings

Our study sought to examine the potential of offshore wind energy for Australia.

First, we examined locations considered feasible for offshore wind projects, namely those that were:

  • less than 100km from shore
  • within 100km of substations and transmission lines (excluding environmentally restricted areas)
  • in water depths less than 1,000 metres.

Wind resources at those locations totalled 2,233GW of capacity and would generate far more than current and projected electricity demand across Australia.

Second, we looked at so-called “capacity factor” – the ratio between the energy an offshore wind turbine would generate with the winds available at a location, relative to the turbine’s potential maximum output.

The best sites were south of Tasmania, with a capacity factor of 80%. The next-best sites were in Bass Strait and off Western Australia and North Queensland (55%), followed by South Australia and New South Wales (45%). By comparison, the capacity factor of onshore wind turbines is generally 35–45%.

Average annual wind speeds in Bass Strait, around Tasmania and along the mainland’s southwest coast equal those in the North Sea, where offshore wind is an established industry. Wind conditions in southern Australia are also more favourable than in the East China and Yellow seas, which are growth regions for commercial wind farms.

Map showing average wind speed
Average wind speed (metres per second) from 2010-2019 in the study area at 100 metres.
Authors provided

Next, we compared offshore wind resources on an hourly basis against the output of onshore solar and wind farms at 12 locations around Australia.

At most sites, offshore wind continued to operate at high capacity during periods when onshore wind and solar generation output was low. For example, meteorological data shows offshore wind at the Star of the South location is particularly strong on hot days when energy demand is high.

Australia’s fleet of coal-fired power plants is ageing, and the exact date each facility will retire is uncertain. This creates risks of disruption to energy supplies, however offshore wind power could help mitigate this. A single offshore wind project can be up to five times the size of an onshore wind project.

Some of the best sites for offshore winds are located near the Latrobe Valley in Victoria and the Hunter Valley in NSW. Those regions boast strong electricity grid infrastructure built around coal plants, and offshore wind projects could plug into this via undersea cables.

And building wind energy offshore can also avoid the planning conflicts and community opposition which sometimes affect onshore renewables developments.

Global average wind speed
Global average wind speed (metres per second at 100m level.
Authors provided



Read more:
Renewables need land – and lots of it. That poses tricky questions for regional Australia


Winds of change

Our research found offshore wind could help Australia become a renewable energy “superpower”. As Australia seeks to reduce its greenhouse has emissions, sectors such as transport will need increased supplies of renewable energy. Clean energy will also be needed to produce hydrogen for export and to manufacture “green” steel and aluminium.

Offshore wind can also support a “just transition” – in other words, ensure fossil fuel workers and their communities are not left behind in the shift to a low-carbon economy.

Our research found offshore wind could produce around 8,000 jobs under the scenario used in our study – almost as many as those employed in Australia’s offshore oil and gas sector.

Many skills used in the oil and gas industry, such as those in construction, safety and mechanics, overlap with those needed in offshore wind energy. Coal workers could also be re-employed in offshore wind manufacturing, port assembly and engineering.

Realising these opportunities from offshore wind will take time and proactive policy and planning. Our report includes ten recommendations, including:

  • establishing a regulatory regime in Commonwealth waters
  • integrating offshore wind into energy planning and innovation funding
  • further research on the cost-benefits of the sector to ensure Australia meets its commitments to a well managed sustainable ocean economy.

If we get this right, offshore wind can play a crucial role in Australia’s energy transition.




Read more:
Super-charged: how Australia’s biggest renewables project will change the energy game


The Conversation


Sven Teske, Research Director, Institute for Sustainable Futures, University of Technology Sydney; Chris Briggs, Research Principal, Institute for Sustainable Futures, University of Technology Sydney; Mark Hemer, Principal Research Scientist, Oceans and Atmosphere, CSIRO; Philip Marsh, Post doctoral researcher, University of Tasmania, and Rusty Langdon, Research Consultant, University of Technology Sydney

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

Why scientists need your help to spot blue whales off Australia’s east coast


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Vanessa Pirotta, Macquarie UniversityBlue whales, the largest animals to ever live, are surprisingly elusive.

They’re bigger than the biggest dinosaur ever was, capable of growing over 30 metres long and can weigh over 100 tonnes — almost as long as a 737 plane and as heavy as 40 elephants. They also have one of the loudest voices, and can talk to each other hundreds of kilometres across the sea.

Why, then, are they so difficult to find in some parts off Australia?

My new research paper recorded only six verified sightings of the pygmy blue whale off Sydney in the last 18 years. Two of these occurred just last year. This blue whale subspecies is known to mostly occur along Australia’s west coast.

Rare sightings like these are important because pygmy blue whales are a “data deficient” animal. Every opportunity we have to learn about them is crucial to help us better protect them.

Blue whales down under

Don’t let its name fool you, the pygmy blue whale can still grow shockingly large, up to 24 metres in length. It’s one of two blue whale subspecies that occur in Australian waters – the other being the Antarctic blue whale, the biggest whale of them all at around 33 metres long.

A blue whale lunging for krill.

Unfortunately, historical whaling hunted blue whales to near extinction in the Southern Ocean. The Antarctic blue whale was depleted to only a few hundred individuals and, while they’re slowly bouncing back, they’re still listed as critically endangered by the International Union for the Conservation of Nature (IUCN).

In contrast, we know little about pre- and post-whaling numbers for pygmy blue whales. Their listing as a data deficient species by the IUCN means we don’t have a full understanding of their population status.

Blue whales can grow to around 30 metres, almost the same length as a 737 plane.
Vanessa Pirotta, Author provided

One reason may be because blue whales are logistically challenging to study. For example, blue whales don’t just hang around in one area all the time. They’re capable of swimming thousands of kilometres for food and to breed.

They can also hold their breath for up to 90 minutes underwater, which can make them hard to spot unless they’re near the surface. To see them, people need to be in the right place at the right time.

This may require scientists to be on dedicated research vessels or in a plane to spot them, which can be expensive and weather-dependent.




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I measure whales with drones to find out if they’re fat enough to breed


This also makes learning about them much harder compared to other, more accessible species, such as coastal bottlenose dolphins.

To learn more about pygmy blue whales in Australia, marine scientists have developed a variety of techniques, including listening to whales talking, taking skin samples and satellite tagging.

While this work is useful, it has focused mainly in areas where pygmy blue whales are known to occur, such as southern and western Australian waters.

Pygmy blue whales are known to feed in the Perth Canyon, Western Australia, and between the Great Australian Bight and Bass Strait during summer. They most likely breed in the Indian and western Pacific Oceans during winter.

But we don’t know much about pygmy blue whale presence in other parts of Australian waters, such as the east coast.

Two bottle nose dolphins
Bottlenose dolphins are more commonly seen.
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How can we conserve a species we know very little about?

Well, it can be tricky. The more information we know, the better we’re placed to assess their conservation needs. But focusing our efforts on species we know nothing about may require a conservative approach until we learn more.

Some would argue it’s better to protect a species we know needs our conservation dollar before spending precious resources on something uncertain.




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Curious kids: do whales fart and sneeze?


Fortunately, Australia has some of the world’s best protection policies for marine mammals, including whales. This means a precautionary approach is already in place to protect these creatures.

Since blue whales are listed as a threatened species, they’re protected under Australia’s primary environment law, the Environmental Protection and Biodiversity Conservation (EPBC) Act.

And on an international level, Australia is a signatory to the International Whaling Commission (the global body for whale conservation) and the Convention on International Trade of Endangered Species (which ensures wildlife trade doesn’t threaten endangered species).

Two blue whales near a boat
Citizen science sightings help contribute to our understanding of blue whale distributions in Australian waters.
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To help uphold this international and national protection, scientists must continue to learn more about data-deficient animals like the pygmy blue whale to help safeguard against known and future threats.

This includes collisions with ships, overfishing, entanglement with fishing gear, increased human activity in the ocean, and climate change, which may affect when and where whales occur.

We need extra eyes

There are more than 14,600 animal species listed as data deficient by the IUCN.

Some, like the pygmy blue whale, are poorly studied. One reason is because they’re cryptic or boat shy, such as the Australian snubfin dolphin.

Or, they might be tricky to see, such as the false killer whale, whose sightings remain irregular in Australian coastal waters. Opportunities to learn more about them occur when they become stranded.

A false killer whale pokes its head out of the water
False killer whales are another data-deficient marine animal.
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So while citizen science sightings of pygmy blue whales may be rare off the Australian east coast, they do help contribute to our understanding of their distribution in Australian waters.

The two sightings of pygmy blue whales off Maroubra, Sydney, last year were within two months of each other. This was thanks to drones (flown under state rules).




Read more:
Climate change threatens Antarctic krill and the sea life that depends on it


This prompted my research review of blue whale sightings off Sydney, which found citizen scientists made similar sightings in 2002 – the first official sighting from land off Sydney — and between 2012-14.

We don’t know exactly what type of pygmy blue whales these are (three distinct groups are recognised: the Indo-Australian, New Zealand and Madagascar groups). However, whale calls detected along Australia’s east coast in previous years suggest they’re most likely New Zealand pygmy blue whales, and they could have been heading to breeding waters north of Tonga.

So, the next time you are by the sea, keep a look out and tell a scientist via social media if you see something interesting. You just never know when the world’s biggest, or shiest, animal may turn up out of the blue.




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Photos from the field: these magnificent whales are adapting to warming water, but how much can they take?


The Conversation


Vanessa Pirotta, Wildlife scientist, Macquarie University

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

How Traditional Owners and officials came together to protect a stunning stretch of WA coast


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Jim Underwood, Australian Institute of Marine ScienceRecent disasters such as the Black Summer bushfires and the Juukan Gorge destruction highlighted the need to put Indigenous people at the centre of decision-making about Australia’s natural places. But what’s the right way to combine traditional ancient wisdom with modern environmental management?

A project off Western Australia’s northwest coast offers a potential way forward. For the first time in the state’s history, Indigenous knowledge has been central to the design of a marine park.

The protected area will span 660,000 hectares northeast of Broome, taking in the stunning Buccaneer Archipelago and Dampier Peninsula. The area comprises thousands of small islands fringed by coral reefs and seagrass beds. The waters support a rich abundance of species such as corals, fish, turtles and dugongs, as well as humpback whales which give birth in the region.

Often, Indigenous input is sought only in the consultation phase of park planning, once maps have been drawn up. But in this case, Traditional Owners co-designed three marine parks with the state government and will jointly manage them. Traditional ecological and cultural wisdom has been embraced and valued, enhancing Western scientific knowledge of a fragile stretch of Australia’s coast.

two men on boat
Traditional owners have been caring for country for thousands of years.
Nick Thake

Caring for Sea Country

The marine park co-design is a collaboration between WA’s Department of Biodiversity, Conservation and Attractions and Bardi Jawi, Mayala and Dambeemangarddee Traditional Owners. It will comprise three adjoining protected areas, each jointly managed by a Traditional Owner group.

The Buccaneer Archipelago region has the state’s highest concentration of Traditional Owner communities living adjacent to an existing or proposed marine park.

Local Indigenous people refer to these areas as “Sea Country”. They depend on the waters for food and to carry out traditional practices, and have cared for them sustainably for thousands of years.

But to date, the state’s conservation reserve system has not adequately protected these unique and exceptionally diverse marine ecosystems.

Industry, fishing and tourism are putting pressure on the region’s environment. In particular, the recent sealing of Cape Leveque Road improved access to the Dampier Peninsula and will result in massive increases in tourism and boating.

Adding to this, marine heatwaves and other climate-related changes pose a serious threat to corals, macroalgae and seagrass.




Read more:
Why Indigenous knowledge should be an essential part of how we govern the world’s oceans


red cliffs at beach
A new sealed road to Cape Leveque will add to pressures on the marine area.
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Genuine two-way partnerships

Combining traditional Indigenous knowledge with a Western approach requires methods that are both culturally appropriate and scientifically robust.

In 2018, Bardi Jawi rangers and staff from the Australian Institute of Marine Science carried out “participatory mapping” to design a mornitoring program for corals and fish. The rangers and marine park planners went on to use this method when designing the marine park.

Participatory mapping starts with Traditional Owners and marine park planners documenting the traditional owners’ ecological knowledge, cultural values and aspirations. From this, maps are developed then built on via on-Country observations.

This process allows scientists to record and understand traditional knowledge of an environment in a way that is also useful for Western conservation and management planning.

people look at map
Participatory mapping involves traditional owners and marine park planners.
Nick Thake

The co-design approach was built on genuine partnerships, mutual respect and two-way learning. The partnerships developed over several years through other joint projects by scientists and Bardi Jawi rangers.

The department listened to and implemented this strong Indigenous voice in the development of the marine parks’ draft plans.

According to the Traditional Owners themselves, the sea is fundamental to the spiritual, social and physical existence. Their diet relies heavily on food from the sea such as fish, turtles, dugongs, crabs and oysters. Under Indigenous laws, traditional owners are required to protect significant features in the sea and for some groups, resources such as pearl shell has traditionally been collected and used for ceremony and trade.

A WA government document outlines how the proposed marine parks contain “special purpose zones” to protect traditional culture and heritage. They allow for seasonal camping areas and places where Traditional Owners can collect customary food and other resources. They will also protect culturally significant features such as cultural sites reefs, seagrass beds and mangrove communities.

The document also says the proposal protects places with “intangible” value related to traditional law, ceremony and stories.

These zones are in addition to sanctuary zones protecting areas of critical habitat, and general use zones where sustainable activities are allowed.




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Will your grandchildren have the chance to visit Australia’s sacred trees? Only if our sick indifference to Aboriginal heritage is cured


man sits while fishing on beach
Science informs the activities allowed in each zone.
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Scientific rigour

Protected areas in marine parks must be sized, spaced and positioned to allow “population connectivity” – the dispersal of eggs, larvae, juveniles and adults through the area.

My involvement in the marine park design included participating in a study which led to recommendations for how best to achieve this connectivity.

The study was part of a bigger program to improve and integrate ecological and social science knowledge in this region. This information was incorporated into two-way learning and planning, which fed into the proposed marine park.

Proven on-ground success

Key to the success of the new marine parks will be the practical capacity of Traditional Owners and Rangers. Indigenous sea ranger groups in the region have already shown they can work with both traditional governance and knowledge structures and non-Indigenous Australian organisations.

What’s more, the Bardi Jawi, Dambeemangarddee and Mayala people have their own healthy country plans. These plans clearly document how they have looked after country for millennia and want to continue this in future.

The Bardi Jawi and Dambeemanagrdee people have also established an Indigenous Protected Area which they’ve successfully cared for since 2013.

Healthy Country, healthy people

Some recreational fishers believe the proposed exclusions are unreasonable. But there is growing evidence fish populations benefit from sanctuary networks. And many local fishers recognise the increasing threats to the region and welcome Traditional Owners playing a larger management role.

It’s hoped the final marine parks plan will find the right balance between the needs of Traditional Owners, commercial and recreational fishing, pearling and other uses.

By involving traditional custodians from the start, there’s every chance we will realise the ancient Indigenous idea that healthy Country means healthy people – and that will benefit everyone.


The author would like to acknowledge the Bardi Jawi, Mayala and Dambeemangarddee Traditional Owners and their continuing culture, knowledge, beliefs and spiritual connection to Country. The author recognises they are Australia’s first scientists.The Conversation

Jim Underwood, Research Fellow and Indigenous Partnerships, Australian Institute of Marine Science

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

‘One of the most damaging invasive species on Earth’: wild pigs release the same emissions as 1 million cars each year


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Christopher J. O’Bryan, The University of Queensland; Eve McDonald-Madden, The University of Queensland; Jim Hone, University of Canberra; Matthew H. Holden, The University of Queensland, and Nicholas R Patton, University of CanterburyWhether you call them feral pigs, boar, swine, hogs, or even razorbacks, wild pigs are one of the most damaging invasive species on Earth, and they’re notorious for damaging agriculture and native wildlife.

A big reason they’re so harmful is because they uproot soil at vast scales, like tractors ploughing a field. Our new research, published today, is the first to calculate the global extent of this and its implications for carbon emissions.

Our findings were staggering. We discovered the cumulative area of soil uprooted by wild pigs is likely the same area as Taiwan. This releases 4.9 million tonnes of carbon dioxide each year — the same as one million cars. The majority of these emissions occur in Oceania.

A huge portion of Earth’s carbon is stored in soil, so releasing even a small fraction of this into the atmosphere can have a huge impact on climate change.

The problem with pigs

Wild pigs (Sus scrofa) are native throughout much of Europe and Asia, but today they live on every continent except Antarctica, making them one of the most widespread invasive mammals on the planet. An estimated three million wild pigs live in Australia alone.

A herd of wild pigs
Wild pigs are one of the most widespread invasive animals on Earth.
Shutterstock

It’s estimated that wild pigs destroy more than A$100 million (US$74 million) worth of crops and pasture each year in Australia, and more than US$270 million (A$366 million) in just 12 states in the USA.

Wild pigs have also been found to directly threaten 672 vertebrate and plant species across 54 different countries. This includes imperilled Australian ground frogs, tree frogs and multiple orchid species, as pigs destroy their habitats and prey on them.

Their geographic range is expected to expand in the coming decades, suggesting their threats to food security and biodiversity will likely worsen. But here, let’s focus on their contribution to global emissions.

Their carbon hoofprint

Previous research has highlighted the potential contribution of wild pigs to greenhouse gas emissions, but only at local scales.

One such study was conducted for three years in hardwood forests of Switzerland. The researchers found wild pigs caused soil carbon emissions to increase by around 23% per year.

Similarly, a study in the Jigong Mountains National Nature Reserve in China found soil emissions increased by more than 70% per year in places disturbed by wild pigs.

Wild pigs turn over 36,214 to 123,517 square kilometres of soil each year.
Shutterstock

To find out what the impact was on a global scale, we ran 10,000 simulations of wild pig population sizes in their non-native distribution, including in the Americas, Oceania, Africa and parts of Southeast Asia.

For each simulation, we determined the amount of soil they would disturb using another model from a different study. Lastly, we used local case studies to calculate the minimum and maximum amount of wild pig-driven carbon emissions.

And we estimate the soil wild pigs uproot worldwide each year is likely between 36,214 and 123,517 square kilometres — or between the sizes of Taiwan and England.

Most of this soil damage and associated emissions occur in Oceania due to the large distribution of wild pigs there, and the amount of carbon stored in the soil in this region.




Read more:
Feral pigs harm wildlife and biodiversity as well as crops


So how exactly does disturbing soil release emissions?

Wild pigs use their tough snouts to excavate soil in search of plant parts such as roots, fungi and invertebrates. This “ploughing” behaviour commonly disturbs soil at a depth of about five to 15 centimetres, which is roughly the same depth as crop tilling by farmers.

Wild pigs uproot soil in search of food, such as invertebrates and plant roots.
University of Kentucky, Department of Forestry and Natural Resources, Forestry Extension.

Because wild pigs are highly social and often feed in large groups, they can completely destroy a small paddock in a short period. This makes them a formidable foe to the organic carbon stored in soil.

In general, soil organic carbon is the balance between organic matter input into the soil (such as fungi, animal waste, root growth and leaf litter) versus outputs (such as decomposition, respiration and erosion). This balance is an indicator of soil health.

When soils are disturbed, whether from ploughing a field or from an animal burrowing or uprooting, carbon is released into the atmosphere as a greenhouse gas.

This is because digging up soil exposes it to oxygen, and oxygen promotes the rapid growth of microbes. These newly invigorated microbes, in turn, break down the organic matter containing carbon.

Wild pigs have a rapid breeding rate, which makes controlling populations difficult.
Shutterstock

Tough and cunning

Wild pig control is incredibly difficult and costly due to their cunning behaviour, rapid breeding rate, and overall tough nature.

For example, wild pigs have been known to avoid traps if they had been previously caught, and they are skilled at changing their behaviour to avoid hunters.




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Dig this: a tiny echidna moves 8 trailer-loads of soil a year, helping tackle climate change


In Australia, management efforts include coordinated hunting events to slow the spread of wild pig populations. Other techniques include setting traps and installing fences to prevent wild pig expansion, or aerial control programs.

Some of these control methods can also cause substantial carbon emissions, such as using helicopters for aerial control and other vehicles for hunting. Still, the long-term benefits of wild pig reduction may far outweigh these costs.

Working towards reduced global emissions is no simple feat, and our study is another tool in the toolbox for assessing the threats of this widespread invasive species.




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The Conversation


Christopher J. O’Bryan, Postdoctoral Research Fellow, School of Earth and Environmental Sciences, The University of Queensland; Eve McDonald-Madden, Associate professor, The University of Queensland; Jim Hone, Emeritus professor, University of Canberra; Matthew H. Holden, Lecturer, School of Mathematics and Physics, The University of Queensland, and Nicholas R Patton, Ph.D. Candidate, University of Canterbury

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