Threats: Invasive Species and Diseases

Section
7. Stop Further Loss of Natural Habitat and Species
Page
7.5

Again, strangely, an unfashionable topic for modern environmentalism, but nonetheless, third on the list of threats to the natural world, with an average score across regions of 13%  (to recap: #1 is habitat loss at 50% and #2 is exploitation of species at 24%).

Pests and weeds represent a generic blanketing of global biodiversity with a suite of hardy, worldwide generalists that outcompete and prey upon native species, or introduce diseases that eliminate local populations. Internationalist progressives that – rightly – rail against the crushing of local cultures and diversity by capitalist ‘pests and weeds’ such as McDonalds and Starbucks and Facebook, have no problem with the same perpetrated on the natural world by Black Rats, cats, mice, Serrated Tussock, Common Mynas, Water Hyacinth, Buffel Grass, and more. To object and to try to protect local natural diversity is, apparently, small-minded and xenophobic.

The impact of pests and weeds is significant almost everywhere on the planet, but perhaps no more so than on island ecosystems where species have evolved in isolation and have few, if any, protective mechanisms. As such, pests and weeds can and have wrought havoc on many Pacific Islands, such as Hawaii and New Zealand. In Hawaii, 394 species are threatened with extinction and 271 species and taxa are already extinct2. In New Zealand, over 70 species of vertebrates and invertebrates are extinct and more than 4000 species are threatened with extinction, including 40% of all plants and birds, and 85% of reptiles3.

(Cleeland, J. 2019. Yellow-nosed Albatross chick. ABC ‘Off Track’)

A graphic example of island vulnerability and the damage wrought by pests was provided by The Australian Broadcasting Corporation’s podcast ‘Off Track’, of the impacts and efforts to control mice on Gough Island in the south Atlantic where the mice can even kill nestling albatrosses! The podcast can be heard here – Where giants nest – Off Track – ABC Radio National . Gough Island is a mecca for seabirds and the introduced mice kill two million prion, shearwater and albatross chicks a year. The predation is such that if unchecked it is estimated that Tristan’s Albatross will be extinct within 20 years and the population of MacGillivray’s and Broad-billed prions has already been reduced from 10 million to two million. Thankfully, the Royal Society for the Protection of Birds is running a mice-eradication program on the island and their progress can be followed here – https://www.goughisland.com/.

(Cleeland, J. 2019. Gough Island. ABC ‘Off Track’)

 

At the larger scale, there is perhaps no better example of vulnerability to invasive species than my island continent, Australia. We have seen already its extremely high level of endemism (see chart of megadiverse countries on webpage 7.2), indicative of long isolation, making its flora and fauna particularly vulnerable. This vulnerability was exposed when global exploration began reaching Australia’s shores in the 1600s and there has been a cavalcade of rabbits, foxes, cats, blackberries, lantana, spurge, cane toads, Capeweed, starlings, and much, much more, ever since.

Australia’s flora is already 12% introduced4, and cats, foxes and rabbits had, and have, a devastating impact on mammals, reptiles and birds, particularly medium-small, ground-dwelling mammals like the Pig-footed Bandicoot, which is now extinct. Australia, it is said, has the worst record in the world for mammal extinction (39 sp.)5 and 549 species of its highly unique fauna is either extinct or resides within the various threat categories established for the official, government, Environment Protection and Biodiversity Conservation Act, 1999.(ibid)

(Gould, J. 1863. The exquisite Pig-footed Bandicoot. Extinct as a result of the introduction of cats, sheep, cattle, disease, and changed burning regimes)

 

Of course, not all losses and threats are due to invasive species, but the toll they take on Australia’s flora and fauna is immense, as quantified by John Woinarski (whom we have already ‘met’ in webpage 1.1.2), and 22 other scientists from 16 universities and agencies, in a ground-breaking meta-study of the impact of feral cats and foxes on Australia’s birds, mammals and reptiles6.  Counting the bodies: Estimating the numbers and spatial variation of Australian reptiles, birds and mammals killed by two invasive mesopredators – Stobo‐Wilson – – Diversity and Distributions – Wiley Online Library .

The numbers are so high it is almost impossible to believe, but their rigorous assessment revealed that, on average, each year, cats and foxes in Australia kill:

  • 697 million reptiles
  • 510 million birds
  • 4 billion mammals

They are also such accomplished generalists that foxes eat 350 different species and cats 700 different species. And this goes on day after day (7 million+ animals killed/day!), month after month, year after year.

A good, brief, summary of the paper was done by Aaron Bunch for AAP and the Daily Mail7:

 

“An incredible 2.6 billion Australian native animals fall victim to feral cats and foxes each year, a new study finds

  • About 697 million reptiles, 510 million birds, 1.4 billion mammals killed annually 
  • Predators played a major role in the decline and extinction of native animals
  • The research found Australian management practices were not effective
  • Impact from predators will continue to be severe without targeted management

By AARON BUNCH FOR AUSTRALIAN ASSOCIATED PRESS

PUBLISHED: 16:57 AEDT, 17 March 2022 | UPDATED: 16:57 AEDT, 17 March 2022

 Cats and foxes are taking a heavy toll on Australian wildlife, killing 2.6 billion reptiles, birds and mammals each year, a study has found.

The predators’ severe and widespread impact is likely to continue without targeted management and control, Charles Darwin University says.

‘Since foxes and cats were introduced to Australia by Europeans, they have played a major role in the declines and extinctions of many native animals,’ ecologist John Woinarski said.

More than one million native Australian birds are killed every day across the country by cats

Despite this, most of the country does not have effective management practices in place.

Researchers found cats and foxes killed 697 million reptiles, 510 million birds and 1.4 billion mammals annually across the nation.

There are an estimated 1.7 million foxes in Australia that kill 350 species of Australian native mammals, reptiles and birds, including forest animals such as possums and gliders.

The carnivore is found across 80 per cent of the country and only absent from Tasmania and the monsoonal tropics.

‘We found that fox densities and impacts are highest in temperate southern mainland Australia,’ terrestrial ecologist Alyson Stobo-Wilson said.

‘In temperate forests they collectively kill at least 1000 animals per square kilometre per year.’

There are an estimated 1.7 million foxes in Australia that kill 350 species of Australian native mammals, reptiles and birds, including forest animals such as possums and gliders

Cats are more numerous and have a wider diet that includes more than 700 species of native mammals, reptiles and birds.

They hunt most of their prey around urban areas, where feral cats kill 5670 animals per square kilometre per year and pet cats take 13,100.

Professor Woinarski said the impact from predators would continue to be severe and widespread without targeted management.

‘To be effective management programs need to be highly strategic as numbers of both of these predators can rebound quickly when management is not on-going or is piecemeal across a landscape,’ he said.

A research team comprised of 23 scientists from 16 universities and conservation agencies examined more than 50,000 poo and stomach samples across the country.

The study is published in the conservation journal Diversity and Distributions.

Foxes and cats have played a major role in the declines and extinctions of many native animals and will continue without targeted management and control”.

 

 

 

 

 

 

 

1 WWF. 2020. Living Planet Report 2020 – bending the curve of biodiversity loss. WWF, Gland, Switzerland.

2 Jacobi, J. 2016. Status and Trends of Hawaiian Flora and Fauna. May 11th, USGS <hawaiibiodiversity.org>

3 <predatorfreenz.org>

4 Australian National Botanic Gardens: Australian Flora Statistics https://www.anbg.gov.au/aust-veg/australian-flora-statistics.html

5 Department of Agriculture, Water and Environment, Environment Protection and Biodiversity Conservation Act, 1999 – List of Threatened Fauna <EPBC Act List of Threatened Fauna (environment.gov.au)>

6 Stobo-Wilson, A., et.al. (23 authors). Counting the bodies: Estimating the numbers and spatial variation of Australian reptiles, birds and mammals killed by two invasive mesopredators. March 15th, Diversity and Distributions – a journal of conservation biogeography.

7 Bunch, A. 2022. An incredible 2.6 billion Australian native animals fall victim to feral cats and foxes each year, a new study finds. March 17th, AAP/Daily Mail.

Explore Other Natural Habitat and Species

7.1 Introduction

New York is an exciting, mesmerising place. Human culture is extraordinary and often wonderful. Our powers of transformation of the natural world seem limitless. The trouble is, we don’t seem to be able to stop, let alone want to stop. How far ...

7.2 State of Habitat

The Worldwide Fund for Nature’s exceptional ‘Living Planet Report 2020’1, Fig. 19 – reproduced below, attempts to show the global distribution of highly modified, largely natural, and in-between habitats. The dark green areas approximat...

7.3 Threats: Land Clearing and Direct Habitat Loss

This is the big one. As pointed out in 7.1 and 7.2 it accounts for over half of all population declines (see Figure 5, webpage 7.2) of native species and is as obvious as it is crude. We burn, chop, bulldoze, log, graze, and drain remaining habita...

7.4 Threats: Species Overexploitation

After land clearing and direct habitat loss, the next biggest threat for native species is overexploitation. It accounts for approximately 24% of declines1 (see webpage 7.2, figures 4 and 5) and can be as simple and direct as overhuntin...

7.5 Threats: Invasive Species and Diseases

Again, strangely, an unfashionable topic for modern environmentalism, but nonetheless, third on the list of threats to the natural world, with an average score across regions of 13%  (to recap: #1 is habitat loss at 50% and #2 is exploitation of s...

7.6 Threats: Fire

Running across and through almost all threats to habitat is fire. Whether indirectly, through clearing, draining and ‘opening up’ of the bush, and as a result of climate change, or directly, through the deliberate lighting of fires, we are seeing ...

7.7 Threats: Erasing Nature from the Mind

I am going to help you here before you make a terrible faux pas and condemn yourself as a “morally repugnant”  ‘conservationist’, or worse, an old-fashioned ‘preservationist’. You cannot see this picture of the Peruvian Amazon. Look awa...

7.8 Habitat and Species Protection Goals

The most relevant international goals for habitat and species protection for the latest decade, 2010-20, were the so-called ‘Aichi goals’. (‘Aichi’, because the location where the UN Convention on Biological Diversity was signed by 193 signatory n...

7.9 Acting for Habitat and Species

Everything in T10 is designed either to increase the protection of habitat and species, or reduce the pressures on same. As such, actions outlined in each of the 10 sections will – directly or indirectly – make a significant contribution. This sai...

7.10 The Future

Jorgen Randers was one of the authors of the seminal ‘Limits to Growth’ in 19721, as well as the 30-year update published in 20042. In 2012 he published ‘2052 – A Global Forecast for the Next Forty Years’3. It woul...

Explore Other Sections

1. Build the Nature-Human Relationship
1. Build the Nature-Human Relationship 1.1 Articles 1.2 Art Installations 1.3 Books 1.4 Buildings 1.5 Film, Documentaries, Podcasts 1.6 Music 1.7 Paintings 1.8 Photographs 1.9 Poems 1.10 Spiritual Responses
1/11

1. Build the Nature-Human Relationship

This section is designed to foster appreciation and insight that will – hopefully – lead to novel ways to build a better relationship between human beings and Nature. This section is also atypical ...
2. Reduce Consumption
2. Reduce Consumption

2. Reduce Consumption

I hope Reneé Descartes would forgive us for saying that, at least for the modern world, he was wrong.  When, in 1637, he said: “I think, therefore I am”, he could not have anticipated that the majo...
3. Replace God of Growth with God of Quality
3. Replace God of Growth with God of Quality

3. Replace God of Growth with God of Quality

In a supposedly secular age there has arisen a global religion and god like never before, a religion whose reach and power makes every other belief system before it seem pitiful and insignificant: ...
4. Work, Volunteer, Act for the Environment
4. Work, Volunteer, Act for the Environment

4. Work, Volunteer, Act for the Environment

What we do in our day-to-day lives can have great impact. Section Four divides up these actions into three groups – Work (4.2 & 4.3), Volunteering (4.4), and Action, e.g. voting, protesting, et...
5. Reduce Population
5. Reduce Population

5. Reduce Population

Even on top of Mt. Everest, in one of the remotest, most difficult places on earth, there is a great traffic-jam of people jostling for position. And yet, ever more vociferously, we deny that overp...
6. Ensure Media Acknowledgement of Environmental Context
6. Ensure Media Acknowledgement of Environmental Context

6. Ensure Media Acknowledgement of Environmental Context

The media is one of the three, great ‘poles’ of power in the world (alongside political and corporate power) and how they frame and present ‘the environment’ has a profound effect on how we respond...
7. Stop Further Loss of Natural Habitat and Species
7. Stop Further Loss of Natural Habitat and Species

7. Stop Further Loss of Natural Habitat and Species

New York is an exciting, mesmerising place. Human culture is extraordinary and often wonderful. Our powers of transformation of the natural world seem limitless. The trouble is, we don’t seem to be...
8. Assist Energy Descent and Transition
8. Assist Energy Descent and Transition

8. Assist Energy Descent and Transition

Our current energy largesse is an extraordinary ‘gift’, an unprecedented gift of the ages; millions of years to produce and from millions of years ago. Coal, oil and gas, forming...
9. Support New, Environmentally-Aware, Economic Systems
9. Support New, Environmentally-Aware, Economic Systems

9. Support New, Environmentally-Aware, Economic Systems

Just as with the previous section – ‘Energy’ – which is, inescapably, all about fossil fuels so pre-eminent and extraordinary has been their dominance and transformation of the world in the last 20...
10. Reduce Wastes to the Rate of Natural Assimilation
10. Reduce Wastes to the Rate of Natural Assimilation

10. Reduce Wastes to the Rate of Natural Assimilation

Section 10 will attempt to organise this enormous topic by addressing the context and status of pollution in 10.2, before focussing in on air pollution; particularly greenhouse gas pollution and cl...