How the bleating tree frog invaded Lord Howe Island

The story of the cane toad is one of many from history that involves the misguided introduction of exotic animals to vulnerable areas. When Europeans first arrived in Australia they missed the sights and sounds of the homeland and brought over many animals for familiarity and comfort, some of which are now considered to be the most destructive in Australia. But the deliberate introductions of animals for aesthetics and agriculture are not the only pathways for invasive species. Lots of organisms sneak through customs and immigration as stowaways and by human carelessness.

Lord Howe Island, as with many remote islands, has a unique and exciting, but vulnerable ecosystem.

Lord Howe Island, as with many remote islands, has a unique and exciting, but vulnerable ecosystem.

As we reported in our article in the journal PLOS ONE this year, paradise destination Lord Howe Island has become yet another recent victim of the carelessness of trade and transport. The World Heritage listed group of islands comprises stunning volcanic mountains surrounded by the world’s most southern coral reef. It sits several hundred kilometres off the coast of New South Wales and is home to only a few hundred residents that work in tourism and local industries.

Far-flung islands like Lord Howe are frequently protected by the vast oceans that surround them, but the isolation that protects them also makes them vulnerable. Volcanic islands rise from the sea and the animals and plants that live there are restricted from breeding with organisms on the mainland. In many cases, wildlife on remote volcanic islands is endemic – meaning it’s found there and nowhere else. Lord Howe Island has remained largely pristine since it was settled, with lots of untouched forest and a lagoon teeming with wildlife. Sadly though, lots of the endemic wildlife of Lord Howe has been devastated by introduced animals.

The bleating tree frog - small, but noisy!

The bleating tree frog – small, but noisy!

Despite this knowledge, the march of invasive animals continues. The bleating tree frog, a small noisy amphibian from south-eastern Australia, was introduced to Lord Howe Island accidentally – likely with a boat load of supplies, in the 1990s. To investigate how the frog got to the island, we took genetic samples from the Lord Howe population of frogs and compared them with the genetic information of the bleating tree frogs on the mainland to find their closest relatives. We were able to determine that the Lord Howe Island population originated in northern coastal New South Wales.  While we were there we also collected data on the distribution of the frogs across Lord Howe Island, their breeding activity and habitat use. We found that the frog is widespread and successfully making use of most habitats on the island, including the forested areas, cattle pastures and buildings.

The habitat of picturesque Lord Howe Island has remained largely untouched, but the wildlife has been negatively impacted by the introduction of non-native species.

The habitat of picturesque Lord Howe Island has remained largely untouched, but the wildlife has been negatively impacted by the introduction of non-native species.

Due to their intolerance of seawater, amphibians are rare on volcanic islands such as Lord Howe. They must be introduced by humans to be able to colonise such isolated places. The bleating tree frog has been the only frog that has successfully invaded Lord Howe Island so far, but without careful consideration for the future, other animals may follow its path. Although it remains to be seen if the bleating tree frog will be a disaster to the Lord Howe Island wildlife, scientists continue to call for greater biosecurity controls and awareness to help prevent further animals and plants slipping through the net and destroying native systems.

Citation: Plenderleith TL, Smith KL, Donnellan SC, Reina RD, Chapple DG (2015) Human-Assisted Invasions of Pacific Islands by Litoria Frogs: A Case Study of the Bleating Tree Frog on Lord Howe Island. PLoS ONE 10(5): e0126287. doi:10.1371/journal. pone.0126287

This work is published in an open access journal, which means anybody can read it! Find it here.


Just how much animal blood do vegetarians have on their hands?

An online article claiming vegetarians are causing more animal deaths than meat eaters continues to cause arguments between the two camps. I am amazed this story is still doing the rounds. My understanding is that the original article appeared in The Conversation in 2011, maybe (it’s not all that clear in the article – there’s a link, but no reference) inspired by a book by Peter Singer. This week, IFLS has discovered it and it has been copied and shared and passed on in social media and via e-mail. The Conversation article represents one of the few pieces of literature (to my knowledge it is not what the scientific community would consider a true piece of peer-reviewed published research) that suggests meat eating is “better” than a vegetable-based diet and consequently has received a lot of attention, particularly (in my experience) from meat-eaters. It has probably been quite the boost for the associated authors’ careers. I have seen similar responses to articles refuting climate change…

My biggest concern with the original article (and therefore any further articles which claim scientific substance) is that it is based on figures of the number of mice killed per hectare of arable land, compared with the number of pasture raised cattle killed for meat. Even assuming that the questionable figures are accurate in the first place, it makes no mention of mice deaths in cattle pasture. In my view, they should have analysed the number of ALL sentient beings killed in each farming practice, since they are concluding from the mouse/cattle data that there are more individual deaths in arable farming than meat.

Also of significance is the displacement of animals which is also ignored in the article. Pasture is a dramatically different ecosystem to a native, unimproved grassland. This article considers the killing of mice as the only significant problem, but there are many more that will die or not be born as a result of the decreased area of habitat, as native animals are pushed out by cattle and sheep.

The article also ignores import/export, which is a major factor in Australian agriculture and the food industry. I don’t know the current figures, but about 10 years ago, Australia was simultaneously the world’s second largest importer and exporter of beef. Aside from us destroying our native habitat to produce cattle for an overseas market, we also import and export huge amounts of vegetable matter for food. Australia is part of the global market and food trade routes pass in and out of our productive country.

There is also a suggestion by the author that the rangelands can only be used as cattle grazing or arable land. I would argue that although there may be no nutritional value in not farming land, by reducing the pressure caused by invasive species (such as cattle) and the direct manipulation of the habitat required to do as such in some areas, the increase of intensity in areas currently used as arable fields is at least in part mitigated.

The author states: ” if you want to minimise animal suffering and promote more sustainable agriculture, adopting a vegetarian diet might be the worst possible thing you could do” which, aside from the sensationalist, deliberately vague language, is not the same message of the next paragraph: “we should choose the way that causes the least unnecessary harm to animals.” which is also not the same as “sustainable agriculture”. The author does later touch on the surface of sustainability in agriculture, but the piece of research that this article is primarily based upon does not have any significant claims either way about sustainability. The message of this article is confused as well as erroneous.

Lastly, it is essential to remember that the book was published by an ethicist. Whilst I don’t think that alone is grounds to discredit it, it does explain why much of the bigger ecological picture has been ignored. The untangling of ethics and ecology is a long-standing problem, as can be attested to by anyone trying to perform research in the field. In this story though, the application of ecological principles to what started as a purely ethical discussion is abused and/or misguided.

So if you are going for steak, please make it kangaroo. I am still undecided entirely about the merits of it – there is no shortage of examples of species being eaten to extinction – but as long as we don’t all immediately do it, it’s probably the better choice at present. This is an important discussion to continue and we have a responsibility to research and question the impact of our diet, so please do not cherry pick the numbers to suit your lifestyle. Ethics, ecology and food security are real and important issues affecting us now and in the future.

Shark week special

Sharks swim in human-infested waters. Our fair weather relationship with the sea, our disrespect for our marine environment and our fear of the unknown, fuelled by media sensationalism puts undue stress on all ocean-going creatures. More recently, sharks have taken the brunt of this issue*, to the point where we have started to appease swimmers with inhumane and unethical treatments of sea life, causing death, disruption and suffering. All this, despite opposition from marine biology experts.

Sharks do not represent a real risk to us; even when we swim in their habitat. Not a real risk. A quick browse of the The International Shark Attack File will show how small the risk really is. Not like driving a car or getting married (to someone who might kill or injure you) and certainly not like cigarettes or fatty food. The act of swimming in the ocean is more likely to kill you through drowning than shark attacks.

Killing sharks offers a visible reduction in their numbers and therefore a perceived reduction in the perceived threat. Rare, endangered species (such as white sharks) are actually targets of the programmes. It also reduces numbers of all animal “bycatch”. Sometimes more so than the target species, as recognised by the authorities that continue to implement the programmes.

Sharks are bioindicators (a living being, or group thereof, that signifies the health of an ecosystem). They eat dead matter in the oceans. They are incredibly diverse. They perform the tasks of an apex predator, keeping the species below them in the food web healthy and in equilibrium. Sharks are more useful than the credit they are afforded. Sharks are more important than I have space to write.

A recent study showed that sharks could be removed and released, safely and successfully whilst reducing shark attacks and eliminating the need for killing, inhumane or otherwise. The location of the study, Brazil, has one of the largest number of shark attacks in the world and this is a promising step in reducing shark attacks and respect for the life of our oceans.

We need sharks more than we realise, but perhaps more importantly, right now they need us. So spread the word about the low low risk of shark attacks. Sign petitions to stop the drumlines and write to your politicians about reducing the harm we are doing to the oceans. We will miss them if they go.

*Most of this research appears to be open access (which means you can read it for yourself) and I implore you to see what the scientists have to say on the issues addressed briefly here.

Hazin, F. H. V. & Afonso, A. S. (2014) Response: A conservation approach to prevention of shark attacks off Recife, Brazil. Animal Conservation, 17(4), 301-302.

House, D. (2014). Western Australian Shark Hazard Mitigation Drum Line Program 2014-17.
Meeuwig, J. J., & Ferreira, L. C. (2014). Moving beyond lethal programs for shark hazard mitigation. Animal Conservation, 17(4), 297-298.

Shiffman, D. (2014). Keeping swimmers safe without killing sharks is a revolution in shark control. Animal Conservation, 17(4), 299-300

This is the only photo I have of a shark, but it's one I took and I was very excited!

This is the only photo I have of a shark, but it’s one I took and I was very excited!

P.S. I make no excuse for three marine-centric articles in a row. The saltwater portion of our planet is the most significant, the most endangered and the least known. Because we don’t live within its limits we are foolish enough not to protect it to the standards we should.

What is your motivation for conservation?

Although potentially controversial, I am a strong advocate for conservation based mainly on intrinsic value.

We also know of the financial value of wild areas or animals (safari brings many tourist dollars for example) and the environmental goods and services argument (e.g., we need rivers as a source of fresh water).

I am planning a research paper investigating these motivations and would love to hear from you (regardless of your background/occupation or education). Are you motivated to conserve or preserve? Why? Does it make you happy just to know that you walk the same planet as koalas, or when you get in the ocean you know there’s a blue whale out there somewhere in the same water? Do you enjoy garden visitors such as butterflies or birds? Are you worried that the cure for cancer may be found in the rainforests that we are logging? And/or do you appreciate that we need trees to breathe and a sustainable source of food to eat?

Please let me know in the comments below. Thanks!

The problem of plastic bags

Plastic bags are an environmental menace from their very origins (as the finite resource of oil, the extraction and processing of which has its own problems) to the difficulties in recycling the product, “responsible” disposal in landfill and the irresponsible littering of our terrestrial environments, freshwater bodies and oceans with these eyesores. Clean Up Australia reports that “Plastic has remained the most common category of rubbish picked up on Clean Up Australia day over the last 20 years. In 2009, it made up 29% of all rubbish found. Of the plastic rubbish found, 17.6% were plastic bags with an average of 40 plastic bags being found at each Clean Up site.”

Modern life presents us with many opportunities to increase convenience, but at cost to the planet. Richer countries of the world are mostly responsible for the largest impacts, with Brits using about 300 bags a year each , Australians use 200 a year and the NRDC reports that Americans take home 1500 a year, which works out to be four a day, each. This represents a ludicrous waste of precious resources in the name of convenience or laziness by people who will probably never see the problems these unnecessary pollutants cause firsthand.

The third of July was International Bag Free Day. This initiative is something the Europeans do exceptionally well. Awareness of waste and pollution is high in Europe. The giving of free plastic bags at point of sale in supermarkets was not as culturally ingrained in some areas of the continent as it is in other parts of the world and has been banned in some countries. The environment is afforded higher status in Europe than it is elsewhere and surplus and refuse are not far from the minds of those that grew up with wartime rationing and a culture of repairing and reusing. That’s not to say that Europe doesn’t produce plastic waste – it does; and lots of it. But we still have a lot to learn from initiatives such as the Spanish creation of “International Bag Free Day” which was largely overlooked by Oceania and the Americas (although it should be noted that some areas are improving the situation, such as the City of Fremantle).

The consumers of Northern Europe have been subjected to measures to reduce plastic bag waste and programmes of plastic waste reduction have been successful. Since 2002, a plastic bag from a supermarket in Ireland has incurred a levy (originally 15 Euro cents, the tax has since increased, and will likely continue to increase, but is currently capped at 70 c). The result is a 90% decrease in the use of those bags. Perhaps more exciting is that reports of stakeholder feedback have been very positive. The reasons for this include education of the public into the problems that plastic bags cause. The Irish example shows the importance of a cultural shift as well as the introduction of legislation.

In lieu of government action to this very serious problem, we can all take immediate action to reduce the production, consumption and disposal of the unsustainable plastic carrier bag. Regular use of reusable bags (particularly ones made of natural fabrics, not plastic) is an easy and immediate mitigation measure. Avoid excessive plastic packaging on foodstuffs and keep an eye open for biodegradable alternatives. Also, when given the opportunity, do as the Irish do and spread the word about reducing plastic bag waste.



From the National Oceanic and Atmospheric Asministration, USA

Photograph from the National Oceanic and Atmospheric Administration, USA. Plastic bags imitate food items to marine creatures, leading to massive problems associated with the ingestion of innappropriate material. For shocking examples of the consequences, see:


Bahri, G. (2005). Sustainable Management of Plastic Bag Waste. The Case of Nairobi, Kenya.

Convery, F., McDonnell, S., & Ferreira, S. (2007). The most popular tax in Europe? Lessons from the Irish plastic bags levy. Environmental and Resource Economics, 38(1), 1-11.

Davidson, J. Explanatory Memorandum to the Single Use Carrier Bag Charge (Wales) Regulations 2010.

Hawkins, G. (2001). Plastic bags Living with rubbish. International Journal of Cultural Studies, 4(1), 5-23.

Khoo, H. H., & Tan, R. B. (2010). Environmental impacts of conventional plastic and bio-based carrier bags. The international journal of life cycle assessment, 15(4), 338-345.

Poortinga, W., Whitmarsh, L., & Suffolk, C. (2013). The introduction of a single-use carrier bag charge in Wales: Attitude change and behavioural spillover effects. Journal of Environmental Psychology, 36, 240-247.

Verghese, K., Jollands, M., & Allan, M. (2006, November). The litterability of plastic bags: key design criteria. In Fifth Australian Conference on Life Cycle Assessment (pp. 22-24).


Fish need protection too

Recently, the news has been full of reports of Culum Brown‘s article published in Animal Cognition asserting fish as sentient (to all intents and purposes, feeling) and they should be afforded the same protections and respect of other vertebrates. It seems that we are less keen to include fish on our moral compass because they do not tick charismatic macrofauna boxes. Yet evidence is increasingly showing that there is more to fish cognition than we previously thought. It is now widely accepted that fish have effective memories and even count numbers. Fish are aware of pain, even if they don’t experience it as we do (the lack of a neocortex means that they experience a feeling probably closer to what we experience as stress or fear, not pain). Although largely subjective, all this information implies suffering. In other words, fish suffer when subjected to something that humans would experience as pain.

Brown’s review came hot on the heels of a report by the ABC that a Ph.D. thesis produced by Miriam Sullivan of The University of Western Australia that suggests that pet fish do not have the love and care they require or deserve. Because they live in water and are covered in scales, it appears that fish are generally considered less significant. Sullivan encourages people to be more aware of the welfare of their pet fish. Historically fish have been considered something of a disposable pet; a first lesson in animal care for young children and a matter of little concern if their wellbeing is compromised. None of this will be of any surprise to anyone that has ever won a goldfish at a fair, or flushed one down a toilet (not recommended).

With or without sentience, the ability to feel pain, emotion and stress levels, fish are vital components of our aquatic and marine ecosystems. Fish comprise large amounts of biomass in the oceans and throughout our freshwater systems. They partake in food webs that span terrestrial and aquatic environments, they store chemicals and alter the chemical composition of the waters in which they live and they alter the physical conditions of their habitats. Fish are hugely influential in their environments and therefore hugely influential in our environments. Fish influence our daily lives, whether we are aware or not. Our own sentience could be considered in question to fishes…

Fish are an important source of protein for hungry mouths around the world, yet they are also a delicacy for greedy gastronomes that bypass the sustainable fisheries advice produced by the likes of the Australian Marine Conservation Society. Our palates are considered more important than the ecosystem and struggling fishermen desperately collect the very last individuals from ever remote areas. Orange roughy is frequently found on the fish shelves of supermarkets, despite the evidence that shows the extreme threat to the species by fishing (briefly, they are long-lived, late maturing large fish, the populations of which have been known to crash dangerously in the past). Tuna is another popular food fish, eaten frequently, over-exploited constantly. Eaten by the rich and spoilt. Easy to overlook, given that fish live in water and are covered in scales.

I will close with a couple of images. This one produced by WWF:

And even more powerful, credited to Sea Shepherd*:
Panda2 Accessed 29/06/2014

Agrillo C, Dadda M, Bisazza A (2007) Quantity discrimination in female mosquito Fish. Animal Cognition 10:63–70

Brown, C. (2014). Fish intelligence, sentience and ethics. Animal Cognition: 1-17 (online early)

Rose, J. D. (2002). The neurobehavioral nature of fishes and the question of awareness and pain. Reviews in Fisheries Science 10(1), 1-38

Zion, B., Karplus, I., & Barki, A. (2012). Ranching acoustically conditioned fish using an automatic fishing machine. Aquaculture, 330, 136-141

*I could not find this on their website, but it is reproduced on many other websites, unanimously crediting Sea Shepherd.

What they said:

Cane toads were introduced to Australia against the advice of multiple scientists. Why do we struggle so hard to learn?!

From today’s Conversation:


Why is our wildlife in trouble? Because we’re ignoring science

By Emma Burns, Australian National University

From reef dredging, to shark culling, to opening old-growth forests to logging, environmental policies are leaving Australia’s wildlife exposed to threats. The reason, we propose, is that society and government are often ignoring science – particularly ecology.

In a recently published book, more than 80 Australian environment professionals looked at what we have learned from studying ecosystems.

This book is based on long-term field research in numerous ecosystems. From this research, there are examples of science both being used and ignored in management and policy.

There is some good news. Forest studies have led to more sustainable forestry in Tasmania, and potentially soon in Victoria. And new restoration techniques are being trialed to protect endangered woodlands in the Australian Capital Territory.

But there’s still a long way to go. Here are three examples where science is seemingly being ignored by current environmental policy.

Alpine grazing

Under a trial approved by the federal government, cattle are now once again grazing in the Alpine National Park.

There is no scientific case for the trial. Since the 1940s scientists have been monitoring the alpine ecosystems.

For instance we know that hard-hooved animals such as cattle, sheep, horses, deer and pigs have significant negative impacts. These include changes to species composition, ecosystem dynamics, and fewer herbs such as Billy Buttons and Snow-daisies.

These studies also clearly demonstrate that grazing by domestic livestock does not reduce the frequency or severity of fire in the Australian alps, and can actually increase the risk of fire, as grazing encourages growth of flammable shrubs.

As a consequence of these studies, grazing of sheep and cattle had been phased out of most alpine areas. It poses a clear threat to the alpine ecosystem and natural heritage values of Alpine National Park, and we know that when grazing stops, the alpine ecosystems recover — albeit slowly, and future recovery is unlikely to be as robust as past recovery because environmental conditions are changing.

Alpine Billy Button
Photo by Henrik Wahren

Culling fruit bats

Queensland and New South Wales are currently culling fruit bats, despite evidence that culls do not reduce health risks or work.

The threatened spectacled flying fox (Pteropus conspicillatus), targeted as part of the culls, also falls under conservation regulations and provides free services for human society, such as dispersal of pollen and seeds. But many humans fear them because of Hendra virus, and dislike them because urban camps are smelly and noisy, and because they damage commercial fruit crops.

Spectacled Flying-foxes
Photo by A. McKeown

Regular calls are made for their conservation status to be downgraded and for management interventions such as camp removal and culling to be adopted. But a ten-year study that we referred to of the habits of spectacled flying foxes demonstrates that apparently simple solutions like moving or destroying camps will ultimately fail because the species is nomadic — naive individuals are always arriving at camps meaning that camps easily re-establish at the site or nearby.

The often repeated claims that flying-fox populations are exploding are also not supported by the research.

Forest management

Recently Prime Minister Tony Abbott suggested that too much forest is locked away from logging and blames “green ideology” for this. We don’t need ideology driving decision making about forest management but more science would be good.

Research on the effects of the 2009 Black Saturday fires in Victoria shows that a decline in hollow bearing trees, which is leading to declines in some fauna, has been linked to these high severity fires and a long history of timber harvesting. On the basis of this research, as well as economic factors, there is a public campaign to change this area’s land tenure from State Forest to National Park.

Professor David Lindenmayer proposes a Giant Forest National Park

However this research is specific to forests in Victoria, and the story may be different in other forest systems. Each system in question needs independent research.

How do we get more science in policy?

Environmental scientists, researchers and policy-makers have a “social imperative” to increase scientific knowledge in policy. Alongside our work on ecosystems, we developed a policy handbook to guide policy makers. And we encourage more ecologists, and their institutions, to distill and communicate their science in similar ways.

It’s not too late, but scientist and policy-makers need to work together and act with the urgency, scale and intelligence needed to meet our environmental challenges.

The book and policy handbook referred to in this article were supported by the Terrestrial Ecosystem Research Network. TERN has catalysed collaborations between researchers dedicated to ecological research but who would have been unlikely to work together without support from TERN.

The Conversation

Emma Burns’ position is funded through the Terrestrial Ecosystem Research Network (TERN). The Long Term Ecological Research Network (within TERN), of which she is the Executive Director, receives funding from the Australian Government.

Ary Hoffmann receives funding from Australian Research Council and the Australian Government through the Terrestrial Ecosystem Research Network

David Lindenmayer receives funding from the Australian Research Council and the Australian Government through the Terrestrial Ecosystem Research Network and the National Environmental Research Program

Dick Williams is associated with activities funded by the Australian Government through the Terrestrial Ecosystem Research Network.

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