Invasive predators are eating the world’s animals to extinction – and the worst is close to home


Tim Doherty, Deakin University; Chris Dickman, University of Sydney; Dale Nimmo, Charles Sturt University, and Euan Ritchie, Deakin University

Invasive species are a threat to wildlife across the globe – and invasive, predatory mammals are particularly damaging.

Our research, recently published in Proceedings of the National Academy of Sciences, shows that these predators – cats, rats and foxes, but also house mice, possums and many others – have contributed to around 60% of bird, mammal and reptile extinctions. The worst offenders are feral cats, contributing to over 60 extinctions.

So how can we stop these mammals eating away at our threatened wildlife?

Counting the cost

Our study revealed that invasive predators are implicated in 87 bird, 45 mammal and 10 reptile extinctions — 58% of these groups’ contemporary extinctions worldwide.

Invasive predators also threaten 596 species classed as vulnerable, endangered or critically endangered on the International Union for the Conservation of Nature Red List. Combined, the affected species include 400 birds, 189 mammals and 149 reptiles.

Twenty-three of the critically endangered species are classed as “possibly extinct”, so the number of extinctions above is likely to be an underestimate.

Until now, these shocking statistics have been unknown, and the heavy toll of invasive predators on native biodiversity grossly underappreciated. Species extinctions attributed to invasive predators include the Hawaiian rail (Zapornia sandwichensis) and Australia’s lesser bilby (Macrotis leucura).

Australia’s lesser bilby, now extinct.

Who are the worst offenders?

We found that three canids (including the red fox and feral dogs), seven members of the weasel family or mustelids (such as stoats), five rodents, two primates, two mongooses, two marsupials and nine species from other families negatively impact threatened species. Some of these species, such as hedgehogs and brushtail possums, don’t immediately spring to mind as predators, yet they are known to prey on many threatened species.

Feral cats threaten the most species overall (430), including 63 that have become extinct. This equates to one-quarter of all bird, mammal and reptile extinctions – making the feral cat arguably the most damaging invasive species for animal biodiversity worldwide.

Five species of introduced rodent collectively threaten 420 species, including 75 extinctions. While we didn’t separate out the impacts of individual rodent species, previous work shows that black rats (Rattus rattus) threaten the greatest number of species, followed by brown rats (R. norvegicus) and Pacific rats (R. exulans).

The humble house mouse (Mus musculus) is another interesting case. Despite their small size, house mice have been recorded eating live chicks of albatrosses, petrels and shearwaters.

Other predators that threaten large numbers of species are the domestic dog (Canis familiaris), pig (Sus scrofa), small Indian mongoose (Herpestes auropunctatus), red fox (Vulpes vulpes) and stoat (Mustela erminea).

Invasive mammalian predators (clockwise from top left): feral dog, house mouse, stoat, feral pig, feral cat, brushtail possum, black rat, small Indian mongoose and red fox (centre).
Clockwise from top-left: Andrey flickr CC BY 2.0 https://flic.kr/p/4M2E7y; Richard Adams flickr CC BY 2.0 https://flic.kr/p/7U19v9; Mark Kilner flickr CC BY-NC-SA 2.0 https://flic.kr/p/4D6LPe; CSIRO CC BY 3.0 http://www.scienceimage.csiro.au/image/1515; T. Doherty; Toby Hudson CC BY-SA 3.0 https://commons.wikimedia.org/wiki/File:BrushtailPossum.jpg; CSIRO CC BY 3.0 http://www.scienceimage.csiro.au/image/10564; J.M.Garg CC BY-SA 3.0 https://commons.wikimedia.org/wiki/File:Herpestes_edwardsii_at_Hyderaba.jpg; Harley Kingston CC BY 2.0 https://flic.kr/p/ceWFr7 (centre).

Island species most at risk

Species found only on islands (insular endemics) account for 81% of the threatened species at risk from predators.

The isolation of many islands and a lack of natural predators mean that insular species are often naive about new predators and lack appropriate defensive responses. This makes them highly vulnerable to being eaten and in turn suffering rapid population decline or, worse, extinction. The high extinction rates of ground-dwelling birds in Hawaii and New Zealand — both of which lack native mammalian predators — are well-known examples.

Accordingly, the regions where the predators threatened the greatest number of species were all dominated by islands – Central America and the Caribbean, islands of the Pacific, the Madagascar region, New Zealand and Hawaii.

Conversely, the continental regions of North and South America, Europe, Africa and Asia contain comparatively few species threatened by invasive predators. While Australia is a continent, it is also an island, where large numbers of native birds and mammals are threatened by cats and foxes.

Along with feral cats, red foxes have devastated native mammals in Australia.
Tom Rayner

Managing menacing mammals

Understanding and mitigating the impact of invasive mammal predators is essential for reducing the rate of global biodiversity loss.

Because most of the threatened species studied here live on islands, managing invasive predators on islands should be a global conservation priority. Invasive predators occur on hundreds of islands and predator control and eradication are costly exercises. Thus, it is important to prioritise island eradications based on feasibility, cost, likelihood of success and potential benefits.

On continents or large islands where eradications are difficult, other approaches are needed. This includes predator-proof fencing, top-predator restoration and conservation, lethal control, and maintenance of habitat structure.

Despite the shocking statistics we have revealed, there remain many unknowns. For example, only around 40% of reptile species have been assessed for the Red List, compared to 99% for birds and mammals. Very little is known about the impact of invasive predators on invertebrate species.

We expect that the number of species affected by invasive predators will climb as more knowledge becomes available.


This article was co-authored by Al Glen from Landcare Research, New Zealand.

The Conversation

Tim Doherty, Research Fellow, Deakin University; Chris Dickman, Professor in Terrestrial Ecology, University of Sydney; Dale Nimmo, Lecturer in Ecology, Charles Sturt University, and Euan Ritchie, Senior Lecturer in Ecology, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University

This article was originally published on The Conversation. Read the original article.

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Snake Eats Crocodile in Queensland


The link below is to an article that includes a number of photos of a Water Python eating a crocodile in Queensland, Australia.

For more visit:
http://www.smh.com.au/queensland/snake-eats-crocodile-after-epic-fight-in-queensland-20140303-33xz8.html

A plague of hornets in China is killing people and eating bees


Grist

asian-giant-hornet-image

If you’ve always wanted to visit China, this … this might not be the best time. Thanks to climate change, massive numbers of Asian giant hornets (which are the size of your thumb) have been rolling through Shaanxi Province, eating honeybees, and stinging humans to death. And they could be coming to your area next.

View original post 351 more words

Article: Octopus Eating a Gull


The link below is to an article about an Octopus eating a Gull. The article includes pictures.

For more, visit:
http://www.birdfellow.com/journal/2012/04/27/who’s_up_for_lunch_a_gull_eating_octopus_in_victoria_bc

QUEENSLAND: GIANT SPIDER EATING BIRD


A massive Golden Orb Weaver Spider has allegedly trapped a Chestnut-breasted Mannikin in its web and begun to eat it in pictures circulating the web this week. The photos were taken in the backyard of a property at Atherton near Cairns in northern Queensland, Australia.

When first looking at the pictures it is easy to think that the photos are fake or that they have been set up, but wildlife experts claim that the photos are genuine. The report first surfaced in The Cairns Post.

Golden Orb Weaver Spiders usually prey on large insects and not birds. It is unlikely that the spider would be able to consume the entire bird.

View the pictures at:

http://www.freewebs.com/spider-eats-bird/

Or view the footage below:

CROCODILE ATTACK: TRAPPING BEGINS NEAR COOKTOWN


The body of Vietnam veteran Arthur Booker, of Logan, Queensland, has still not been found following a suspected crocodile attack earlier this week. It is thought that Booker was taken by a large crocodile while checking crab traps along the Endeavour River near Cooktown on Tuesday. All that has been found in the search for the missing 62-year-old man has been his footwear and watch.

The search for Booker has now entered a new stage with police suspending their search of the river. Queensland Environmental Protection Officers (EPA) have now begun to lay crocodile traps in the area so that crocodiles can be examined for remains without harming or killing them.

The investigation into the disappearance of Arthur Booker has yet to determine if he was in fact taken by a crocodile, although this remains the most likely scenario.  There are a number of large crocodiles inhabiting the area, including the 6m ‘Charlie.’

Charlie is known to be responsible for the loss of pet dogs, livestock, eating a 3.5m crocodile and was once seen taking a horse.

The probable crocodile attack has once again brought the call for crocodile culling back into the public arena. At the moment any thought of culling by officials has been dismissed.

BELOW: Footage reporting the disappearance of Arthur Booker