Double-dividend: exploring the co-benefits of invasive species management and climate action

Feral Herald |

Invasive species are one of the biggest threats to biodiversity worldwide and one of Australia’s worst environmental problems. So it’s not a big surprise to learn invasive animals and weeds may also affect carbon emissions.

Evidence is emerging to show when we manage invasive species there can be co-benefits for the climate. Here’s four areas where eradication, control and management of invasive species could help to keep our precious carbon stores in good shape so they can continue to play their crucial function in a healthy environment.

Feral pigs erode the soil, releasing carbon dioxide

Feral animals can contribute to climate change by eroding and destroying carbon sinks such as soil, wetlands and peatlands. Take feral pigs which are like “mini tractors”, uprooting the soil as they search for food, releasing the carbon stored within.

Researchers at the University of Queensland recently looked into the impact of feral pigs on climate change globally and found they produce as much carbon dioxide as 1.1 million cars every year. Those emissions aren’t shared equally around the world either – in fact, due to our large populations of feral pigs, Australia and New Zealand account for 60% of those emissions. The report’s lead author, Dr Christopher O’Bryan, says it’s a conservative estimate and emissions could be three or four times higher.

Feral horses are ravaging peatlands, our ancient carbon stores

Peatlands — such as the sphagnum bogs of our alpine and sub-alpine regions — are nature’s secret weapon when it comes to tackling climate change. Globally, they store over a third of the planet’s soil carbon. That’s more than in all the world’s forests. Put another way: 5% of the world’s carbon emissions is due to damage to peat moss.

In Australia’s alpine regions, feral horses, deer and pigs are ravaging Australia’s precious peatlands, turning them from a safeguard against climate change into a driver of emissions.

What’s worse is peatlands take thousands of years to recover. A study on the impacts of feral horses in the Australian alps shows peat soils build up about 1 metre every 3,000 years. This means vital carbon stores in Australia’s alps damaged by feral horses over just a few decades, will take thousands of years to fully recover.

Invasive weeds like gamba grass can increase the risk and intensity of bushfires, increasing carbon emissions

Gamba grass is one of Australia’s most alarming invasive species, fuelling hotter, more dangerous fires that threaten homes and livelihoods. This weed can transform savanna habitats into monocultures. It is a highly invasive species that is native to Africa but has become established in parts of Australia, including the Northern Territory.

“Gamba grass is the worst of the worst when it comes to invasive weeds in Northern Australia. It can grow up to four metres high and fuels hotter, more intense fires which are transforming the Top End by reducing tree cover, changing water availability, depleting nutrients and increasing greenhouse gas emissions,” says Andrew Cox, CEO of the Invasive Species Council.

Feral buffalo produce high amounts of methane

Researchers from Charles Darwin University have been evaluating culling feral buffalo for carbon credits. With one adult buffalo emitting the equivalent of more than two tonnes of carbon dioxide per year, that’s a possible two carbon credits per buffalo. This approach could bring benefits to both landowners and the environment, helping to fund invasive species management. The report earmarks the future potential for other invasive species, saying: “While we estimated the direct enteric emissions from only one species in northern Australia, the same approach could be applied to other species across Australia, including cattle, camels, goats, and deer.”

Nature’s complexity means we are continually learning more about the intricate web of systems that sustain life on Earth. While further research is needed to better understand the intersection between invasive species management and climate change mitigation, it’s an exciting space that could deliver a double-dividend for nature and climate.

Ensure you’re signed up to receive future editions of Feral Herald where we will be inviting scientific leaders in the field of invasive species and climate change to share their latest findings.

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Help protect NSW!

Our expert team has written a list of policy asks detailing exactly what the next NSW government needs to do to stamp out some of the worst invasive species impacts across the state. But they will only become a reality if every key political candidate at the 2023 NSW state election hears about it from you!

Dear National Deer Management Coordinator,

Please accept this as a submission to the National Feral Deer Action Plan.

[Your personalised message will appear here] 

I am very concerned about the spread of deer and am pleased that a national plan has finally been developed. Without urgent action, funding and commitment from all levels of government it is clear that feral deer will continue to spread and damage our environment.

The feral deer population in Australia is growing rapidly and spreading across the country, damaging our natural environment, causing havoc for farmers and foresters and threatening public safety. Unlike much of the world where deer are native, our plants and wildlife haven’t evolved to deal with these heavy hard hooved animals with a voracious appetite.
With no natural predators and an ability to adapt to almost all environments, they could occupy almost all of Australia unless stopped. Despite this, state and territory governments have been slow to respond and in Victoria and Tasmania they are still protected by law for the enjoyment of hunters.

This plan should be adopted by all governments but must also be underpinned by dedicated funding and clear responsibilities. A plan without funding or accountability is a plan that will fail and Australia cannot afford for this to fail.

In order to prevent the spread of feral deer and reduce their impact on our native wildlife, ecosystems and agriculture, I ask that the following recommendations be adopted for the final National Feral Deer Action Plan:

1. All federal, state and territory governments should adopt the National Feral Deer Action Plan and declare feral deer to be a priority pest animal species.

2. All federal, state and territory governments should commit to:

  • Contain deer to the existing large population areas.
  • Reduce and eradicate smaller and isolated populations.
  • Protect important environmental assets such as world and national heritage areas.
  • Develop and fund regional plans and strategies to manage deer populations which involve land managers across all tenures.

3. In order to drive action and the success of this plan, there should be dedicated Commonwealth funding and support for:

  • A permanent national feral deer coordinator position.
  • A permanent federal feral deer action committee with representatives from the commonwealth and state and territory governments and the environmental and agricultural sectors.
  • An ongoing public education campaign on feral deer.
  • A network of regional feral deer coordinators to drive local action across tenures.

4. The expected outcomes for the plan need to be more ambitious, with clear interim targets including:

  • Within one year, all States and Territories should have in place arrangements to implement the National Feral Deer Action Plan, including allocating dedicated funding for implementation.
  • Within one year, feral deer management plans should be developed for key environmental assets of national significance, including the Tasmanian Wilderness World Heritage Area, the Greater Blue Mountains, the Australian Alps, the Gondwana Rainforests and the Wet Tropics of Queensland.
  • Within five years coordinated landscape scale management should be in place where land owners, land managers, government and community are demonstrably working together.

5. A national feral deer containment map with three zones should be adopted. It should be more ambitious than the zone map in the current draft plan and there should be greater clarity in the naming of the zones. Improvements that should be adopted include:

  • Renaming the zones to better reflect the management intention to ‘Containment Zone 1’ (the current large population zone), ‘Containment Buffer Zone 2’ (the current buffer zone) and ‘Eradication and prevention Zone 3’ (the current small isolated population zone).
  • The NSW northern rivers area should be in the eradication and prevention zone as there are few feral deer currently in this region and eradicating isolated populations and preventing spread into this area is still possible.
  • The whole of South Australia should be in the eradication and prevention zone as eradication is the goal of the SA Government.
  • The Tasmanian region in the containment zone should be smaller to reflect greater ambition and potential for eradication of deer populations.
  • In eastern Victoria areas such as Wilson’s Promontory, Westernport islands and the Mornington Peninsula should be in the eradication and prevention zone.

6. There should be consistent laws and regulations across all states and territories that:

  • Recognise feral deer as a pest animal and treat them as such.
  • Establish a clear responsibility for all landholders and managers to be involved in feral deer control programs.
  • Set clear penalties to stop the wilful or negligent release of feral deer.
  • Prevent new deer farms in areas where no feral deer are present and phase out all deer farms in the eradication and prevention zone.
  • Enable enforcement of compliance, including on government land.

I support the follow principles being adopted in the final National Feral Deer Action Plan:

  • Feral deer are a pest and should be treated as such on all tenures, except on approved deer farms.
  • Federal, state and territory governments have a responsibility to fund the outcomes under this plan.
  • All land managers in areas where feral deer are present have a responsibility to be involved in feral deer control programs.
  • The focus of management efforts should be on eradication of isolated, satellite populations, protection of key environmental assets currently impacted and stopping the spread to new regions.
  • Feral deer control should be undertaken humanely, safely and professionally according to agreed protocols and all tools which meet this criteria should be adopted, including aerial control.
  • Funding for coordination, regional planning and community engagement is necessary for effective feral deer management.
  • Ongoing management and follow up control efforts are required to achieve long lasting results.
  • Rules and regulations should be consistent across jurisdictions and land tenures.
  • Recreational hunting is not an effective strategy for feral deer control and should not be relied upon.
[Your name]
[Your email address]
[Your suburb], [Your state]