One cat, one year, 110 native animals: lock up your pet, it’s a killing machine

Anton Darius/Unsplash, CC BY

Jaana Dielenberg, The University of Queensland; Brett Murphy, Charles Darwin University; Chris Dickman, University of Sydney; John Woinarski, Charles Darwin University; Leigh-Ann Woolley, Charles Darwin University; Mike Calver, Murdoch University, and Sarah Legge, Australian National University

We know feral cats are an enormous problem for wildlife – across Australia, feral cats collectively kill more than three billion animals per year.

Cats have played a leading role in most of Australia’s 34 mammal extinctions since 1788, and are a big reason populations of at least 123 other threatened native species are dropping.

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But pet cats are wreaking havoc too. Our new analysis compiles the results of 66 different studies on pet cats to gauge the impact of Australia’s pet cat population on the country’s wildlife.

The results are staggering. On average, each roaming pet cat kills 186 reptiles, birds and mammals per year, most of them native to Australia. Collectively, that’s 4,440 to 8,100 animals per square kilometre per year for the area inhabited by pet cats.

More than one-quarter of Aussie households have pet cats.
Jaana Dielenberg, Author provided

If you own a cat and want to protect wildlife, you should keep it inside. In Australia, 1.1 million pet cats are contained 24 hours a day by responsible pet owners. The remaining 2.7 million pet cats – 71% of all pet cats – are able to roam and hunt.

What’s more, your pet cat could be getting out without you knowing. A radio tracking study in Adelaide found that of the 177 cats whom owners believed were inside at night, 69 cats (39%) were sneaking out for nocturnal adventures.

Surely not my cat

Just over one-quarter of Australian households (27%) have pet cats, and about half of cat-owning households have two or more cats.

Many owners believe their animals don’t hunt because they never come across evidence of killed animals.

But studies that used cat video tracking collars or scat analysis (checking what’s in the cat’s poo) have established many pet cats kill animals without bringing them home. On average, pet cats bring home only 15% of their prey.

Wes Mountain/The Conversation, CC BY-ND

Collectively, roaming pet cats kill 390 million animals per year in Australia.

This huge number may lead some pet owners to think the contribution of their own cat wouldn’t make much difference. However, we found even single pet cats have driven declines and complete losses of populations of some native animal species in their area.

Documented cases have included: a feather-tailed glider population in south eastern NSW; a skink population in a Perth suburb; and an olive legless lizard population in Canberra.

Urban cats

On average, an individual feral cat in the bush kills 748 reptiles, birds and mammals a year – four times the toll of a hunting pet cat. But feral cats and pet cats roam over very different areas.

Pet cats are confined to cities and towns, where you’ll find 40 to 70 roaming cats per square kilometre. In the bush there’s only one feral cat for every three to four square kilometres.

So while each pet cat kills fewer animals than a feral cat, their high urban density means the toll is still very high. Per square kilometre per year, pet cats kill 30-50 times more animals than feral cats in the bush.

The impact of roaming pet cats on Australian wildlife.

Most of us want to see native wildlife around towns and cities. But such a vision is being compromised by this extraordinary level of predation, especially as the human population grows and our cities expand.

Many native animals don’t have high reproductive rates so they cannot survive this level of predation. The stakes are especially high for threatened wildlife in urban areas.

Pet cats living near areas with nature also hunt more, reducing the value of places that should be safe havens for wildlife.

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A hidden toll: Australia’s cats kill almost 650 million reptiles a year

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The 186 animals each pet cat kills per year on average is made up of 110 native animals (40 reptiles, 38 birds and 32 mammals).

For example, the critically endangered western ringtail possum is found in suburban areas of Mandurah, Bunbury, Busselton and Albany. The possum did not move into these areas – rather, we moved into their habitat.

What can pet owners do?

Keeping your cat securely contained 24 hours a day is the only way to prevent it from killing wildlife.

It’s a myth that a good diet or feeding a cat more meat will prevent hunting: even cats that aren’t hungry will hunt.

A bell on a cat’s collar doesn’t stop hunting, it only makes hunting a little harder.
Wes Mountain/The Conversation, CC BY-ND

Various devices, such as bells on collars, are commercially marketed with the promise of preventing hunting. While some of these items may reduce the rate of successful kills, they don’t prevent hunting altogether.

And they don’t prevent cats from disturbing wildlife. When cats prowl and hunt in an area, wildlife have to spend more time hiding or escaping. This reduces the time spent feeding themselves or their young, or resting.

In Mandurah, WA, the disturbance and hunting of just one pet cat and one stray cat caused the total breeding failure of a colony of more than 100 pairs of fairy terns.

Benefits of a life indoors

Keeping cats indoors protects pet cats from injury, avoids nuisance behaviour and prevents unwanted breeding.

Cats allowed outside often get into fights with other cats, even when they’re not the fighting type (they can be attacked by other cats when running away).

Two cats in Western Australia stopped fairy terns from breeding.
Shutterstock

Roaming cats are also very prone to getting hit by a vehicle. According to the Humane Society of the United States, indoor cats live up to four times longer than those allowed to roam freely.

Indoor cats have lower rates of cat-borne diseases, some of which can infect humans. For example, in humans the cat-borne disease toxoplasmosis can cause illness, miscarriages and birth defects.

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For whom the bell tolls: cats kill more than a million Australian birds every day

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But Australia is in a very good position to make change. Compared to many other countries, the Australian public are more aware of how cats threaten native wildlife and more supportive of actions to reduce those impacts.

It won’t be easy. But since more than one million pet cats are already being contained, reducing the impacts from pet cats is clearly possible if we take responsibility for them.

Jaana Dielenberg, Science Communication Manager, The University of Queensland; Brett Murphy, Associate Professor / ARC Future Fellow, Charles Darwin University; Chris Dickman, Professor in Terrestrial Ecology, University of Sydney; John Woinarski, Professor (conservation biology), Charles Darwin University; Leigh-Ann Woolley, Adjunct Research Associate, Charles Darwin University; Mike Calver, Associate Professor in Biological Sciences, Murdoch University, and Sarah Legge, Professor, Australian National University

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

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Ditch plastic dog poo bags, go compostable

Don’t do these doggie-doo don’ts.
Shutterstock

M. Leigh Ackland, Deakin University

We humans have a habit of avoiding our waste. We find organic waste particularly unpleasant. We bag it and dispose of it as soon as possible.

Even the most environmentally conscious person would rather not handle something like decomposing food or dog poo with their bare hands. Plastic bags are often the first step we take to disconnect ourselves from our waste – until we can get rid of it somewhere else.

Traditional plastic bags are made from ethylene, derived from petroleum or natural gas. Ethylene does not degrade easily. So these types of bags are major contributors to plastic pollution.

More than three-quarters of plastic ends up in landfill, while up to 5% finds its way to the ocean. Only 9% of plastics are recycled.

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Many environmentally conscious pet owners are turning to biodegradable bags as the solution to their doggy-doo woes, but many brands won’t break down in landfill, compounding the problem. Alternatives are at hand, though, with compostable bags and community sharing programs that can help non-composters.

A ‘biodegradable’ statement on a bag isn’t enough: it needs a logo

“Biodegradable” means something that can potentially be broken down naturally in the environment, particularly by microorganisms but also by other factors such as heat, light and oxygen. We usually think of biodegradable materials as derived from natural sources such as plants, but synthetic materials can also be biodegradable.

But there are issues with the term “biodegradable bag”. Bags can be labelled biodegradable, but after being used and discarded they might only partly decompose because the conditions are not right for full decomposition. Or else the decomposition might take a long time.

Full decomposition means complete conversion of the bag into simple substances such as carbon dioxide and water that can be re-used by microorganisms like bacteria and fungi.

Food becomes poop, which becomes…?
Carol Von Canon/Flickr, CC BY-NC-SA

The biodegradability of plastic can be measured in a laboratory using methods such as carbon tracking. There are international standards for testing biodegradability of plastics. The International Organization for Standardization (ISO) has developed these standards.

Unfortunately, ocean and landfill environments are not conducive for degradation of biodegradable plastic. Marine environments often don’t contain the right types of microorganisms needed to break down plastics, or there aren’t enough to be effective in a reasonable time frame. Landfill conditions often lack oxygen, which limits the types of microorganisms that can exist there.

Compost, however, provides an ideal environment for biodegradation. Compost contains a diverse range of organic materials that support the growth of many different varieties of organisms.

DNA sequencing has revealed the huge diversity of microorganisms that exist in compost. These include bacteria, fungi and invertebrates that can digest a wide range of organic materials. In particular, fungi are found to possess enzymes that are capable of breaking down many different organic substances.

Compost to the rescue

You can now buy compostable bags. These are a type of biodegradable bag that is suitable for disposal in compost only (not in the ocean or landfill!).

How can you tell if a compostable bag can actually be fully broken down in compost? Standards Australia produces standards for the biodegradability of plastic bags. Code AS 4736-2006 specifies a biodegradable plastic that is suitable for overall composting (which includes industrial processes) and other microbial treatment, while AS 5810-2010 specifies home composting.

Standards Australia provide a brief overview of the testing carried out for AS 5810-2010. Other countries have similar standards – for example, the US has ASTM code D6400, which certifies that the material meets the degradation standard under controlled composting conditions.

The Australian Bioplastics Association administers a voluntary verification scheme. This enables manufacturers or importers to have their plastic materials tested and certified.

There is a double arrow logo you can watch out for on bags that have been certified as home compostable and there is a seedling logo for certified compostable. If you cannot locate a certified compostable bag in your area, you can source them online. Make sure they have have the certified compostable logo of the country from which they come.

It is interesting to observe the biodegradability of a plastic bag in your compost heap, as I did with a compostable bag full of dog poo. After two weeks buried in the compost, the only evidence of the bag was some small black fragments. These looked like leaf mould except they had the print from the bag label on them. In comparison, a normal plastic bag buried at the same time was completely unaltered. Of course, this experiment is not proof of total bag degradation – proper laboratory testing would be required for this.

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What if you can’t compost?

If you cannot compost, you will probably be relying on your local council to dispose of your waste. If the council uses landfill for waste disposal then there may be no point in using compostable bags for your waste, as landfill does not have the right conditions for composting to occur.

If you have a kerbside green waste collection that is composted, this service most likely will not accept food waste at the moment – which means dog poo is very unlikely to be included. Nor may compostable bags be allowed in green waste collections. Some councils, however, are working towards food organics/green organics waste collections for the future, and these may include compostable bags.

Moyne Shire in western Victoria, for instance, provides compostable bags for dog poo and accepts it along with green waste in its fortnightly “FOGO” collection.

If you have material for composting but do not have a compost heap, you can join Sharewaste. Sharewaste links people who want to recycle their organic waste with their neighbours who can use the waste for composting, worm farms or chickens. So this is a way to avoid sending your organic waste to landfill.

Composting your organic waste is like harvesting rain into your water tank or tapping into sunlight for your energy needs. These things are meaningful beyond their utility; they connect you to nature and give insights into the natural cycles of life on planet Earth.

M. Leigh Ackland, Professor in Molecular Biosciences, Deakin University

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

Here’s what you need to know about exotic pets in Australia

Red-eared sliders were once popular pets but are currently banned in Australia. These turtles are still regularly found in the wild and being kept as illegal pets.
Pablo Garcia-Diaz, Author provided

Pablo García-Díaz, University of Adelaide; Miquel Vall-llosera, and Phill Cassey, University of Adelaide

A taste for owning exotic animals can be addictive – the more flamboyant the better. Earlier this month border security agents found 50 live turtles and lizards smuggled in Lego boxes sent from Indonesia. In April customs officials found a parcel marked “2 pair shoes” that turned out to contain venomous vipers, tarantulas and scorpions.

According to the Animals Medicines Australia 2016 survey some two-thirds of Australian households have pets – more than 24 million animals in total. Not surprisingly, dogs and cats are the most popular (38% and 29% of households, respectively), whereas aquarium fish and birds rank somewhere in the middle (both 12%), and reptiles and less common mammals are kept in some households (both less than 5%).

The federal government largely legislates the owning of exotic pets. The law defines “exotic” as “animals that do not occur naturally in the wild in Australia” – which actually includes dogs and cats. However “domesticated mammals”, which also covers cows, sheep and other farm animals, are generally legal to buy and own. Commercial trade in exotic reptiles and amphibians, on the other hand, has been banned since 1999.

Whether an exotic animal is kept legally or not, some will find their way to the Australian wild through escape or release, posing a potential pest risk. There are some simple things governments and pet owners can do to improve the way this risk is handled, to keep animals and humans safe.

We don’t really know how many exotics are in Australia

Most local councils only require dogs (and sometimes cats) to be registered by their owners. Other pets, whether exotic or native, do not need to be registered. Indeed an owner of an exotic animal is not required to report or register the animal in any way. This means there are very little reliable data and it’s difficult to say how many exotic pets are kept in Australia.

We highlight two cases from our own research: birds and reptiles.

Bird-keeping is common in Australia, particularly of parrots and finches. More than half the bird species traded are exotic and mostly originate in South America, Africa and Asia. Rose-ringed Parakeets are one of the most commonly kept exotic pet bird, and the most frequently reported as having escaped. They are seen as a potential threat because they are a serious agricultural pest in its’ native and exotic distribution, and have a very high risk of establishing in Australia.

The Rose-ringed parakeet is a common pet in Australia and presents a potential biosecurity risk.
Dick Danies/Wikimedia

Reptiles – generally skinks, turtles and dragons – are less popular pets than birds. Nonetheless, judging from the posts on public trading webpages, a variety of native reptile species are kept and traded by hobbyists, also including crocodiles and snakes.

Unfortunately, little is known about native reptile trading in Australia and further research is needed. And while native reptiles can be kept legally, illegal exotic reptiles are a serious problem. In a previous article for The Conversation, we reported that 28 alien reptile species were illegally kept in Victoria between 1999 and 2012. More than a third were highly venomous snakes, posing a real risk to human safety.

Responsibly caring for exotic pets

If you own or want to buy an exotic pet, you must be aware of the regulations that apply to you (you can Google “exotic pet regulations” plus the name of your state or territory). Each jurisdiction keeps official lists of those species that may be kept within their borders, with or without a permit. These lists can be found on local government websites or obtained from their relevant departments.

People should also be able to register all of their pets, including exotic ones. Governments need to promote public awareness of the importance of registration (even if it’s not legally required), and ensure the processes are simple, accessible and affordable.

If you lose your exotic pet, it’s important to alert your state or territory biosecurity agency. Each jurisdiction has its own agency, but examples are the Western Australia Department of Agriculture and Food or Agriculture Victoria. If you want to recover your lost pet the best available option is to report your loss to one of the many missing animal websites.

Governments, when facilitating the registration process, will need to establish best practices to collect and analyse information so that the nature and extent of pet ownership may be better known, monitored and managed.

Ultimately, the burden of safe and responsible pet ownership should be shared. While public awareness is crucial, the key to a sustainable pet trade is mutual partnership between pet owner communities and governments. This is particularly important as pet sales and trade shift further to an online environment.

Pablo García-Díaz, PhD candidate in invasion ecology, University of Adelaide; Miquel Vall-llosera, Assistant Professor in Shinshu University, Japan, and Phill Cassey, Assoc Prof in Invasion Biogeography and Biosecurity, University of Adelaide

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