Tag Archives: conservation

Tasmanian devils reared in captivity show they can thrive in the wild

The Conversation

Tracey Rogers, UNSW Australia

One of the concerns of any conservation breeding program is how well a species raised in captivity will survive when released into the wild.

Evolutionary changes that are beneficial for an individual while in captivity may reduce its fitness when translocated to the wild.

For some species, like many fish, rapid evolutionary changes can occur within the first generation in captivity. And carnivores raised in captivity have a low chance of surviving the first year following their release.

A review of 45 carnivore translocations, which included 17 different species, including the European lynx, European otter and the swift fox, found that if the animals had been raised in captivity they had on average a 30% chance of survival after release.

Save the devil program

All this was a concern then for efforts to help save the Tasmanian devil.

The devil plays an important functional role within the Tasmanian ecosystem and is the last of the large marsupial carnivores.

But the Tasmanian devil is listed as endangered and their population has declined by 80% over the past ten years. This is due largely to the infectious fatal cancer, the devil facial tumour disease (DFTD).

As part of a conservation effort, a disease-free devil population has been established in captivity.

But given the low rate of survival of released captive-raised carnivores in other conservation programs it was important to identify whether their release could play a viable role in the conservation of the Tasmanian devil.

Captive breeding programs are extremely expensive and resource allocation was very tight. So more than 35 institutions helped to set up the captive devil insurance population.

Different types of enclosure setting were used, some intensive zoo style while others had larger pens to allow for a more free range style. The different enclosure types offered different opportunities for the devils to retain their natural behaviours.

We tested the effect of the various captive-rearing methods on the survival and body mass of captive raised Tasmanian devils that were released on Maria Island, off Tasmania’s east coast.

Our study, published this month in CSIRO Wildlife Research, showed that Tasmanian devils raised in captivity before being translocated into the wild had a high survival success (96%). Most of the devils are still alive two years after their release.

The devils gained weight, are hunting and breeding. This is irrespective of the type of captive-rearing method as both zoo style and free range reared animals are thriving.


Release of the devils. Wildlife Management Branch, Department of Primary Industries, Parks, Water and Environment

Natural born killers

One cause of translocation failure in other programs has been that the released animals starve. The captive-raised animals had not learnt foraging and hunting skills. Some carnivorous mammals can lose this natural foraging behaviour in captivity.

But the captive-raised Tasmanian devils adjusted to the wild better than other carnivorous species. This was not only because they were released in the relative safety of an island, but it suggests that the devils’ foraging behaviour does not need to be learnt.


Devils have bone crushing jaws. Wildlife Management Branch, Department of Primary Industries, Parks, Water and Environment.

Devils have a massive head with bone crushing jaws, large tough molars and strong shoulders and neck. They have a very broad approach to what they will eat.

Their diet includes all major critters such as mammals, birds, reptiles, amphibians and invertebrates. Devils have been seen catching gum moths out of the air, slurping tadpoles out of ponds and digging yabbies out of their burrows.

They also live from the intertidal zone to the sub alpine zone. They climb trees like a possum and are good swimmers.

There was less carrion available on Maria Island than on the mainland. Also the captive-raised devils would not have learnt hunting skills while in captivity so we presumed that they would not eat large prey.


Captive devils feeding upon a carcass.

Initially, after the first release, the devils fed on brushtail possums. But relatively soon after we found the devils started to feed on large prey, such as the common wombat and eastern grey kangaroo. These species are much larger than you would predict for a mammal of the devils’ size to prey on.

What’s planned for the devils?

So what does the success of this wild release say for the future conservation of the Tasmanian devil?

The devil facial tumour disease has been detected across the majority of the devil’s range. The wild devil population has been decimated as the disease moved across Tasmania.

It is time to boost the genetic diversity of the wild population. We need to provide the potential for immunity to develop in the species. That’s why it is exciting to have found that the captive-raised devils adjusted so well in the wild.

The next step will be to supplement the wild Tasmanian mainland population by releasing further captive-raised devils, along with those born wild on Maria Island.

But the devils released on the Tasmanian mainland will face other dangers. Alongside the disease they will have to contend with dogs, rodent poison and car collisions.

Clearly there’s some work still to be done, but the Maria Island and captive devils will continue to be an important part of the fight against the deadly facial tumour.

The ConversationTracey Rogers, Associate Professor Evolution & Ecology, UNSW Australia

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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How curiosity can save species from extinction

The Conversation

Merlin Crossley, UNSW Australia

If I had been given one wish as a child I, it would have been that the Tasmanian tiger wasn’t extinct. To me extinction was a tragedy. I expect that many people feel the same way.

But it is not easy to save dwindling populations and prevent extinctions. Sure it takes money, but it also takes knowledge. One simple story about butterflies illustrates the complexity of ecosystems and shows how important research and understanding are to preserving biodiversity.

It is the story of the European butterfly, the large blue or Phengaris arion (Maculinea arion in older literature).

In Australia we have lots of butterflies and literally countless moths; the total number is not known. In the United Kingdom, on the other hand, virtually all species have been described.

I visited England several times as a child, and at one stage I sought to see as many of the 60 different species of butterfly as possible. But I was particularly keen to see the large blue because it was rare. It was the first butterfly recorded in the British Isles in 1795 and was much prized by collectors for the very simple reason that it was so scarce.

But over the years the known populations gradually died out and it was given protected status. Britons made efforts to fence off reserves where it remained but, oddly, its numbers continued to decline. By 1979 it was declared extinct in Britain.

But why had all the steps to save this iconic species failed?

One researcher from Oxford University, Jeremy Thomas, led a team of large blue experts to investigate the ecosystem in which it existed. The first step was to try to understand the butterfly. And there was a lot to understand.

A pretty butterfly that hides a remarkable life cycle.
PJC&Co, CC BY-SA

Interdependence

It is a remarkable species. The female lays eggs on wild thyme flower buds. Each caterpillar bores into the bud and eats the growing seeds. It needs all the energy in the seeds to survive, and if more than one caterpillar is sharing the bud they will fight things out in a cannibalistic bout until only one remains. This is a taste of things to come.

After about a week eating the seeds and flower it drops to the ground and waits until it is found by a special species of ant. It excretes a substance that feeds the ant, but also influences the ant’s behaviour. The ant goes and fetches fellow ants that carry the caterpillar down into the nest.

Once inside the nest the caterpillar does a remarkable thing: it feeds on ant larvae until it finally pupates. When it is ready to emerge as a vulnerable new butterfly it begins making sounds that appear to appease the ants. It then emerges, protected by a guard of ants, and climbs up out of the nest to stretch out its wings.

The critical point is that the large blue doesn’t just depend on any old species of ant, but on very particular species. It has evolved to exude chemicals that influence red ants of the species Myrmica sabuleti or M. scabrinodis.

These ants also have very specific requirements, this time in terms of temperature and moisture. If the ground is too hot or too cold they don’t thrive and other species take over.

Ground temperature and moisture depend on the height of the grass. The grass needs to be short, so grazing is important. It turns out that fencing off reserves actually interfered with the life cycle of the butterfly because the grass grew too long, and the ground wasn’t right for the ants.

Similarly, the spread of myxomatosis and reductions in the rabbit populations also meant the grass grew too tall, again altering ground temperature and helping drive the decline in large blue populations.

Due to the careful work by Jeremy Thomas and colleagues, all this is now known. Fortunately, unlike the Tasmanian tiger, the large blue was extinct only in the British Isles, and not in mainland Europe, thus it has been possible to re-introduce it into Britain.

It has also been possible to manage the habitat to allow grazing so that the ant colonies thrive and the butterfly also seems to be doing well.

Parts of the odd life cycle of this butterfly were known as far back as 1915, but there was no understanding of the connection to the ecosystem and landscape, so the vital step of controlling the grazing was not considered.

The large blue has been successfully returned to Collard Hill
in the Polden Hills in Somerset.

Curiosity

The story shows how things can be complex and inter-connected, and that only by understanding all the facets can one intercede to put things right. It also illustrates how the careful application of science can make a difference.

One can never tell when and how, or even if, new knowledge will ever be useful. Scientists collect knowledge partly because they want to improve the world, but often just out of curiosity.

Sometimes curiosity driven research is criticised as self-indulgent, and unlikely to make a real difference to our circumstances. Sometimes it is said that researchers should just go straight for the biggest problems and tackle them straight on, or that research should be aimed purely at applications. This is increasingly heard these days given the new emphasis on innovation and the commercialisation of research.

But in reality we need science most when we have tried tackling the problem and got stuck. Everything people had tried to preserve the large blue had failed. Only knowledge provided a way forward.

Curiosity driven science often provides solutions when we are stuck and without it we will sometimes remain stuck forever. In the case of the Tasmanian tiger I believe we are stuck forever, but there are many other things to preserve and careful in depth science can make a difference.

The ConversationMerlin Crossley, Dean of Science and Professor of Molecular Biology, UNSW Australia

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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Flake is sustainable gummy shark, except when it’s not

The Conversation

John Ford, University of Melbourne and Robert Day, University of Melbourne

The week before last, I (John) had an appetite for fish and chips. But as I stood at the counter my desire for a sustainable lunch started to make things rather complicated. The names of the fish on the menu were all familiar, but the fillets on display looked nothing like their local namesakes. Except for one: flake.

Dozens of species of shark have fallen under the umbrella term of flake. In this case, it was advertised as local gummy shark.

There is a plethora of conflicting information about whether we should eat shark. Australian fisheries are well managed and considered sustainable on the world stage. Meanwhile, conservation groups say to avoid flake, but local gummy shark fisheries have addressed many of their concerns.

It makes you want to order a hamburger with the lot instead.

In all seriousness, two very important issues stayed with me from this experience: the need to better understand the sustainability of local gummy shark, and the need for clearer labelling of cooked seafood.

Gummy shark: a unique shark fishery

Gummy shark caught in southern Australian waters is considered a sustainable choice by the federal government. The biology of the gummy shark is different from familiar apex predators like the great white, tiger and hammerhead sharks. It is relatively fast growing, has a high reproductive rate and feeds on invertebrates in the sand and mud.

Gummy shark (Mustelus antarcticus) are relatively small sharks, and their ‘gummy’ teeth are suited to eating small crustaceans and fish on the sea floor.
Terry Walker, Author provided

The commercial fishery only catches young adults. It employs a net mesh size that allows smaller fish to swim through and larger mature individuals to bounce off. The fishery is controlled under a total allowable catch which is set at biologically conservative levels, currently at 1836 tonnes each year.

The non-target catch of school shark is a sustainability concern. School shark are considered over-fished and cannot be targeted by fishers.

A rebuilding strategy for school shark is in place including measures such as fishing closures in pupping and nursery grounds, gear restrictions and a low by-catch limit. These appear effective in preventing the targeting of school shark. But they also make it extremely difficult to get good evidence of any recovery in the Australian school shark population.

Previous concerns over sea lion by-catch off South Australia resulted in large and lengthy fishery closures to protect sea lion colonies. This demonstrates the capacity of management to effectively intervene when conservation issues arise.

Gummy shark is not a typical shark species and many of the sustainability concerns raised by environmental groups such as the Australian Marine Conservation Society, GoodFishBadFish and Humane Society International are not as relevant to the gummy shark fishery. Aside from the issue of school shark by-catch, which requires careful monitoring, all other signs point to a biologically and ecologically sustainable fishery in our backyards.

So back at the fish shop the local gummy shark sounds like a sustainable option. But can you trust the label?

‘Fake’ flake on the menu

According to the Australian Fish Names Standard, only two species should be sold as flake: the gummy shark and a related species from NZ, rig. So already the waters are muddied, but surely fish labelled local gummy should be a safe bet for sustainability?

The Australian Fish Names Standard is voluntary and country of origin labelling regulations only apply to raw and frozen product- not cooked meals in cafes, restaurants and fish and chip shops. This means your ‘flake’ might not be gummy shark, or from a local fishery.

This undermines the strong branding of Australian seafood as a leader in sustainability and dis-empowers the customer from making decisions based on science, and the environmental standards in the country of origin.

No country of origin requirements and voluntary fish name standards mean fish labels in takeaways and restaurants questionable.
Taylor Herring/Flickr, CC BY-NC-ND

Furthermore, while it is an offence to describe food dishonestly, the reality in the case of flake is that it can be substituted for any other shark species. A Greenpeace investigation using DNA analysis of samples of flake sold in Melbourne fish and chip shops found that a third were actually school shark, probably imported.

Clearing up seafood labelling

However, things are changing in seafood labelling. Last December a senate enquiry recommended mandatory country of origin labelling for cooked seafood.

In March the Greens and Nick Xenophon, with the support/co-sponsorship of four crossbench Senators, introduced an amendment to the Food Standards Australia New Zealand Act to parliament. This would require the food service sector, including cafes, takeaways and restaurants, to label fish with their country of origin. Similar laws in the Northern Territory have been successful.

Matt Evans’ What’s the Catch program that aired on SBS last year, a campaign by conservation groups, chefs and sections of the Australian commercial fishing industry have drummed up support for better seafood labelling. There is now significant optimism that these laws will pass despite some opposition from seafood importers and the restaurant and catering sector.

Where to from here?

Many of us do our best to purchase our seafood sustainably. However the many seafood sustainability standards and recommendations by conservation groups, third-party accreditors and governments often only serve to confuse.

In truth each of these groups have different definition of “sustainability”. As individuals we could look to align our values with any of the different groups making these making sustainability claims. A promising initiative in this space is the “Common language group”, which recommends some value-neutral information be provided to consumers, including proper seafood labelling.

One thing is certain: Australia is doing better than most of the world on fisheries sustainability. A decision to buy Australian will always carry with it an underlying standard of environmental and social responsibility. It often means our local seafood is more expensive than imports, but then again it is only fair to our fishermen that their product is differentiated in the marketplace.

But we can only make these informed choices if we are provided with accurate information at the fish counter and fish and chip shop and restaurant menus. Mandating the Australian Fish Names Standard and requiring country of labelling laws in the food service sector will be a major step in allowing seafood lovers to better understand where our seafood comes from – and, if they so choose, to get genuine local gummy shark at their local fish and chip shop.

The ConversationThis article was originally published on The Conversation. (Reblogged by permission). Read the original article.


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Let’s stop Tasmania’s swift parrots going the way of the dodo

The Conversation

Dejan Stojanovic, Australian National University

You might have seen recently that swift parrots – little green parrots that migrate between mainland south east Australia and Tasmania – are headed for extinction. In modelling published in Biological Conservation, my colleagues and I found that these parrots could be all but gone within 16 years, largely through being eaten by sugar gliders.

Today, we are launching a crowdfunding campaign to protect swift parrots and two other Tasmanian birds: orange-bellied parrots, and forty-spotted pardalotes. All three of these birds are threatened by sugar gliders. We are tying to develop glider-proof nest boxes, and undertake urgent research to understand how sugar gliders may be affecting these endangered Tasmanian birds. To do this, we’ve teamed up with Australia’s leading political cartoonists to raise money to support our research.

Swift parrots are currently listed as endangered at state, federal and international levels. But our modelling shows that the parrots meet international guidelines for being listed as critically endangered, joining nearly a hundred other animals facing a similar threat of extinction in Australia.

Swift parrot nestlings (Source: Henry Cook)

Parrot conflict zone

Swift parrots are one of only three migratory parrot species (the orange-bellied parrot, also found in Tasmania, is also critically endangered), and they spend their lives following rich patches of flowering trees across the forests of south east Australia.

There are only around 60 orange-bellied parrots left – and sugar gliders have been implicated in their deaths. (Source: Ron Knight, CC BY)

This lifestyle brings them into direct conflict with people, and as a consequence of deforestation, collisions with human made structures, and other changes to their habitat, the species is seriously threatened.

Consequently, swift parrots pose big problems for those trying to save them, and are a regular subject of controversy.

Migratory species such as swift parrots are vulnerable to habitat degradation even in relatively small parts of their range.

This is because the entire population of swift parrots converges on small patches of flowering Tasmanian forest where the right trees occur to breed. Bottlenecks like these magnify the effects of habitat loss and other threats like predation.

Swift parrot nesting habitat has been deforested for agriculture, urban development and logging. Birds looking for a place to nest are squeezed into remaining habitat where they are very vulnerable to other threats.

Nestling swift parrots and their mothers regularly fall prey to sugar gliders.

Sweet possums with a savoury tooth

Recent research revealed that on the Tasmanian mainland, sugar gliders (a species probably introduced to Tasmania) are eating swift parrots in extraordinary numbers. Gliders eat eggs, nestlings and adult female swift parrots, as well as several other bird species that are small enough to subdue.

Forty-spotted pardalotes survive mainly on glider free islands.
(Source: 
Matt Francey, CC BY-NC)

Swift parrots are more likely to be killed by a glider when forest in the surrounding landscape is disturbed. In small patches of nesting habitat where deforestation is severe, gliders can eat up to 100% of swift parrot nests.

These astonishingly high predation rates have worrying implications for the viability of the swift parrot population over the long term. Deforestation in important swift parrot breeding areas is still happening despite the link between forest loss and predation, and is the focus of ongoing dispute.

Given the severe threats faced by swift parrots, we considered it pertinent to reassess whether swift parrots still fit the bill for an endangered classification. To do this, we conducted a population viability analysis for swift parrots using information we gathered from four years of intensive research. Using data on swift parrot movements, predation rates and reproductive success, we modelled how swift parrots might cope with predation by sugar gliders.

Our results reveal that swift parrot populations are on track for population collapse within three generations as a result of sugar glider predation.

We show that even breeding on predator free offshore islands is not enough to buffer swift parrot populations, and the species could decline by a catastrophic 94.7%.

Swift parrot nest (top) later visited by a sugar glider (bottom).
(Source: 
Dejan Stojanovic)

That’s the good news

Our models are best-case scenarios: we ignored other factors that kill swift parrots (collisions with windows, habitat loss, food limitation, inbreeding, disease). Based on our data, swift parrots are on an extinction trajectory, and their current listing as endangered does not reflect their true conservation status.

To qualify as critically endangered under internationally accepted guidelines, a species must decline by at least 80% over three generations, which for swift parrots is 16 years. Our models indicate that the rate of decline of swift parrots exceeds this threshold.

This is very bad news for the conservation of the swift parrot. At present, native forest logging is the principle cause of deforestation in the breeding range of swift parrots. The extent of habitat loss in the swift parrot breeding range is very worrying, and has not abated despite two successive recovery plans highlighting deforestation as a threat.

Sugar gliders can survive in small patches of forest left over after land clearing, and swift parrots are forced into these patches by the lack of alternative habitat.

Given the link between the extent of forest around nests and the likelihood of predation, Tasmanian forest management needs a rethink. Our study shows that business as usual will lead to population collapse of swift parrots.

The evidence is in, and it is time to address the problem.

The ConversationThis article was originally published on The Conversation. (Reblogged by permission). Read the original article.


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Turtle extinction event bodes ill for our waterways

The Conversation

Ricky Spencer, University of Western Sydney

A number of distressed and dead turtles were found by canoeists in the Bellinger River on the north coast of New South Wales on Wednesday February 18 this year. At that time, it was reported by NSW National Parks and Wildlife rangers, NSW Wildlife Information, Rescue and Education Service (WIRES) volunteers and local residents that 30 turtles were affected.

Several days later, the tally increased to 52 and, as of today, more than 300 turtles are dead. But the real toll is far greater, with many more washed away during a flood in late February.

Yet the peril of this one turtle species is more than an isolated issue. It gives us a window into the health of the entire ecosystem around the Bellinger River, and suggests something is very wrong.

Close to the brink

The dead turtles are all from one species, the Bellinger River Snapping Turtle (Myuchelys georgesi), which is a species that only exists in a 25-kilometre stretch of the Bellinger River. The risk of extinction is high.


Infected Bellinger River Turtle with septicemic cutaneous ulcerative disease visible around the eyes.
Source: Rowan Simon

Mortality for infected turtles is 100%. Source: Rowan Simon

National parks have been closed indefinitely and plans are in place to recover healthy turtles from the wild. There are already few juvenile turtles in any Australian river because of sustained annual fox predation, close to 100%.

So the reality is that, even with active management, recovery of the species will take more than a decade if the current disease doesn’t wipe them out.

Ill turtles display symptoms of blindness, growths around the eye (septicemic cutaneous ulcerative disease, or SCUDs) and are extremely lethargic and emaciated. The mortality rate of infected animals is 100%. High mortality combined with an extremely limited range means that this is quite possibly a rapid extinction event.

Window on our waterways

Turtles are an evolutionary success story, having persisted for over 220 million years. Australian freshwater turtles face many threats that permeate every life-history stage, from egg to adult.

The life history of turtles involves high but fluctuating rates of egg and juvenile mortality, which is balanced by extreme iteroparity (i.e. they are long-lived and highly fecund). Threats to adults are generally low.

Human activities have impacted this successful life strategy by increasing mortality of eggs and young, as well as adults. Nest predation rates are extraordinary high and adult turtles frequently become victims of road kill or are killed by foxes as they emerge to nest or disperse.

Turtles are also drowned at water regulation points in wetlands (eg. carp screens), in fishing nets or in irrigation pumps, and killed by fishers. An article from 2012 described that:

[…] a combination of human-induced changes has created a downward spiral so powerful that – without strategic intervention – much of the great turtle lineage will have disappeared by the close of the 21st century.

The possible extinction of an ancient lineage and iconic animal is tragic, but the consequences for the health of our rivers are even more significant.

In most systems, turtles rival fish as the highest vertebrate biomass. They are the major vertebrate nutrient recyclers (i.e. scavengers), a significant herbivore and the top predator.

Scavengers serve an important function by stabilising food webs and are critical in redistributing nutrients. Thus turtles provide a critical ecosystem service by removing decaying animal matter from the environment.

Significant numbers of dead turtles are symptomatic of something wrong with a river or wetland. Given their various roles in an ecosystem, indicators of biological health don’t come much better than freshwater turtles.

The Bellinger River Snapping Turtle consumes food, such as insect larvae, that are highly sensitive to pollution, increased sedimentation or general water conditions. In a river, which changes almost daily because of rainfall, insect populations respond rapidly and are affected by natural changes.

The turtle is adapted to boom-bust cycles of the river and resilient to natural shortages of food. However, if there are chronic issues with the food supply, then turtles will be impacted.


A healthy Bellinger Snapping Turtle. Source: Arthur Georges

Watch the turtles

The crisis with the turtles in the Bellinger River may signal broader effects of a change or breakdown in ecosystem function in the river.

The last mass freshwater turtle mortality event occurred in the lower lakes of South Australia during the millennium drought, when salinity levels rose and many turtles perished after becoming entrapped by growths of marine tubeworms on their shells.

The value of turtles as indicators of aquatic ecosystem health is that their health relates to medium to long-term changes in the river, rather than annual or seasonal fluctuations that occur in potentially environmentally volatile systems.

They are also long-lived and turtles can bio-accumulate toxins in their shells. Regular sampling (shell or nails) of marked individuals can be used to monitor long-term exposure to toxins and pollutants in the river – something that snapshot monitoring of water quality may miss.

Turtles are threatened by chronic reproductive failure, exotic predators, disease, habitat modification and habitat loss. Potential for any recovery is limited by ongoing threats and limited capacity for populations to increase.

The current disease threatening to drive the Bellinger River Snapping Turtle to extinction is a potential window into a long-term breakdown of ecosystem services. The possible extinction of a long-lived ancient species that has survived several million years might be a significant warning sign of the current state of our freshwater environments.

The ConversationThis article was originally published on The Conversation. (Reblogged by permission). Read the original article.


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FactCheck: are kangaroos at risk?

The Conversation

By Daniel Ramp, University of Technology, Sydney and Karl Vernes, University of New England

“Senator Rhiannon embarrasses herself by sharing conspiracy theories about kangaroo numbers being in terminal decline. She only has to drive between Winton and Longreach at night to see the plagues of roos.” Queensland Nationals Senator Barry O’Sullivan, press release, February 13, 2015.

Senator O’Sullivan’s comments, made after Greens Senator Lee Rhiannon raised concern over kangaroo populations being at risk, reflect a common view that Australia is swarming with kangaroos.

But how secure are kangaroo species? Are they in plague proportions, necessitating large-scale killing and a commercial industry, or are they in decline and at risk?

Are ‘roos at risk?

We don’t yet have clear evidence showing kangaroos are at risk of extinction. But we cannot afford to get too comfortable, given their historical decline.

The NSW Scientific Committee last year rejected a 2011 nomination that four species of kangaroos be listed as vulnerable. You can read their preliminary determinations for the four species here, here, here and here.

But despite what Senator O’Sullivan has seen on the night drive between Winton and Longreach (an area adjacent to a national park), Australia is not swarming with kangaroos. A plague is not biologically plausible because kangaroos are slow growing.

Juvenile mortality rates are high and female kangaroos tend to have only three or four joeys survive in their lifetime. Compare that to rabbits, which can produce up to 14 young in a litter. Kangaroo populations, as a whole, do not grow more than 10% in a year.


We don’t have clear evidence yet showing kangaroos are at risk. (Source: AAP Image/Dave Hunt)

While it’s true there are large kangaroo populations in some parts of Australia, in other parts they are scarce. As population numbers are reported to fluctuate a lot within a few short years, it depends on which period you are looking at.

So we should be very careful about blanket statements about “plagues” of kangaroos. They do not represent the overall picture.

Historical decline

Six species in the kangaroo family have gone extinct since European settlement, with over 60 species remaining. Some species remain endangered, like the brush-tailed rock-wallaby, which was killed in the hundreds of thousands for its fur. Others remain in substantial numbers, but human history is littered with examples of causing the extinction of populous animals.

In 1982, CSIRO researchers Short and Grigg reported that 85% of kangaroo populations had been reduced to below one per square kilometre in western Victoria. In Tasmania, the kangaroo population is at 10% of pre-European settlement numbers.

What can we infer from recent surveys?

When asked by The Conversation for data to support her concern that kangaroos are at risk, Senator Rhiannon referred to government records collected over the past 30 years from commercial harvest zones in four states, estimated from aerial surveys of transects. Animals seen from planes are multiplied by correction factors and extrapolated to entire zones.

As the graph below shows, these records showed kangaroo numbers fell between 2001 and 2011. (The federal government stopped providing national kangaroo population numbers online in 2011, although they remain reported on a state-by-state basis.)


National government data showing kangaroo population trends, 2001 to 2011. Graphic by Daniel Ramp, data by Department of the Environment

Referring to a 2011 nomination to list kangaroos as threatened, Senator Rhiannon highlighted a decline of 40% in national populations between 2001 and 2011.

However, population estimates were then reported to increase between 2011 and 2013 due to reasonable rainfalls.

Nationals Senator O’Sullivan has also said that populations in Queensland have more than doubled from about 12 million to more than 25 million over the past decade. The available data says that is true.

Can both be right?

Kangaroo populations grow slowly and decline rapidly during drought. Many localities in Queensland have recorded declines of over 50% since 2013.

Both senators appear to be looking at two different windows of population estimates, ranging between two peaks ending with the 2001 and 2014 droughts.

Senator O’Sullivan also recently said that kangaroos are “taking up to half of the pastures on some drought-stricken properties across Western Queensland”.

However, CSIRO research shows little direct impact on crops and little competition with livestock for pasture. Kangaroos do not benefit from artificial watering points, rarely drinking.

A spokesman for Senator O’Sullivan said that “heavy grazing pressures placed on properties by kangaroos across Western Queensland is anecdotal. However, we feel it is highly reliable.”

The elephant in the room is that the data isn’t really adequate to paint an accurate picture of kangaroo populations in Australia. Both Senator Rhiannon and the NSW Scientific Committee have noted frailties with the data.

Verdict

We don’t yet have data showing that kangaroos are at risk, but we cannot afford to be complacent given their historical decline.

The senators are comparing apples and oranges, looking at different data sets from different time periods and extrapolating to paint a picture of either plague or near-endangerment.

There is less and less space for kangaroos: more kangaroos are killed for meat and skins than any other mammal species, they are killed for trespassing on farmland, shot illegally, hit by vehicles, caught in barbed-wire fences and persecuted by domestic dogs.

If we want kangaroos to remain a part of the Australian landscape and identity, we need better population data upon which appropriate policy can be based.


Review

The article is based on the best available population data collected by the various states on commercially harvested kangaroo species, and the vast scientific knowledge that has been amassed on their biology and ecology.

Kangaroo populations definitely fluctuate with climate, a factor built into harvest models. For example, annual surveys since the early 1980s show dramatic declines (sometimes as high as 97%) related to several droughts from the 1980s to the 2000s, but then (albeit slower) recoveries of the populations during intervening times of better than average rainfall. However, because quotas reflect not only current population estimates but also the modelled impact of current and projected climate on numbers, quotas should protect populations from over-harvesting.

All available evidence points to the industry being sustainable; furthermore, quotas are almost never met, so even fewer kangaroos are harvested each year than sustainable quotas allow for, further buffering the populations from the possibility of over-harvesting.

The author’s comments on complacency, however, are also sensible; over-harvesting kangaroos prior to modern management did result in alarming declines, and the few studies of likely impacts of climate change on large kangaroos suggest a negative effect on these species.

Thankfully, though, and despite recent political wrangling over the issue, it is my view we currently have a carefully managed, well-run and scientifically sound kangaroo monitoring program, which informs the setting of sustainable harvest quotas, which, in turn, should safeguard kangaroo populations well into the future. – Karl Vernes


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Mourn our lost mammals, while helping the survivors battle back

The Conversation

By Dale Nimmo, Deakin University; Euan Ritchie, Deakin University, and Thomas Newsome, University of Sydney

There was a plague of them and one night I got approximately 300 which had been poisoned in the garden during night. This went on for two or three years.

Take a second and have a guess what animal species this quote might be referring to. Here’s a hint, the quote is from western Victoria, Australia, during the 1800s.

What did you guess? A house mouse, or another introduced species like a rabbit?

In fact, the quote refers to a native mammal species, the eastern quoll. A species that was “one of the commonest animals” in southeastern Australia, a species that would plague, is now officially extinct on the mainland. It has been more than 50 years since a confirmed sighting.

Australia has the worst rate of mammal extinctions in the world. More than a third have become extinct since European settlement​, or are currently threatened with extinction. But what about the survivors? And what can we do to prevent further losses?

Research by David Peacock and Ian Abbott has shown that the eastern quoll, Dasyurus viverrinus, was once extremely abundant on mainland south-eastern Australia, but it has not been seen on the mainland for over 50 years.
Michael Barritt & Karen May

A lost world

Few Australians would appreciate just how much our native mammal communities have changed since European arrival more than 200 years ago. Early quotes from books and newspaper articles like the one above, painstakingly collated by researchers, offer some insight.

Early explorers made similar notes about abundant mammals because their dogs were “completely distracted by the numbers of wallabies, paddymelons and kangaroo rats that bounded off on all sides”.

Their poor horses would struggle through the sandy soils that were “full of Wallabi holes”.

Such quotes describe an Australian landscape rich in native wildlife. A landscape that, owing to the decline and extinction of so many mammal species, has radically changed.

The abundant mammals that distracted the dog and made life difficult for the horse probably refer to species long gone. According to researchers, the burrowing bettong, which is now extinct on mainland Australia, was probably the “kangaroo rat” responsible for those pesky holes.

The “paddymelons” and wallabies are probably the eastern hare and/or bridled nailtail wallabies; the former now extinct, the latter now restricted to a few pockets across eastern Australia.

Gone from this earth: Four of the 30 Australian mammal species that have gone extinct since European settlement. The desert rat-kangaroo (top left), the eastern hare-wallaby (top right), the white-footed rabbit-rat (bottom left), and the pig-footed bandicoot (bottom right).

On the bright side

Even with the sad loss of so many native mammals, Australia retains a suite of truly fascinating species, many of which occur right among us.

In Melbourne’s suburb of Cranbourne, populations of southern brown bandicoots persist, fossicking in people’s gardens and dining from dog’s bowls by night.

Species of flying fox survive in our inner cities and darken the dusk sky as they leave their colony for their nightly foraging.

In most major capitals, some possum species are so common as to be an annoyance to many as they bound over roofs and devour prized roses.

Less raucous but arguably more striking sugar gliders and striped possums occupy urban parks, while a range of species of pygmy possums and hopping mice live on in our parks and reserves.

A diverse array of kangaroo species still bound through rural landscapes, sharing paddocks with wombats, echidnas, dingoes and koalas. Platypuses fish for yabbies in farm dams nearby.

The survivors. Australia retains a unique and fascinating mammal fauna, including these species: the sugar glider, western pygmy possum, dingo, spinifex hopping mouse, striped possum, and common wombat.
Sugar glider- Angus McNab, western pygmy possum – Lauren Brown, dingo- Bobby Tamayo, spinifex hopping mouse – Judy Dunlop, striped possum – Jack Ashby, common wombat – Angus McNab

Australia is still blessed with spectacular and globally unique mammals. But we can do better.

Where to next for Australia’s mammals?

As part of the federal government’s National Environmental Science Programme, approximately A$30 million is being devoted to a Threatened Species Recovery Hub.

Australia’s native mammals will undoubtedly be a focus of the hub, as many species are on the brink of extinction.

However, one thing our history of mammal extinctions has taught us is that complacency is our worst enemy. Common species go extinct, and can do so rapidly.

It’s not just about conserving threatened species. The decline of eastern quolls, and many other similarly rapid declines of common species, tell of the need to be vigilant.

On the other hand, species that are regionally extinct should not be forgotten when assessing how our conservation dollar is best spent. This is particularly true for species that perform important functional roles that benefit other species (or entire ecosystems), such as native predators. Just as complacency is to be avoided, an aversion to taking calculated risks and trying new approaches in conservation also jeopardises our species’ chances of survival. We urgently need to go further and be bold if our landscapes are to be restored.

The revival of apex predators across Europe, species such as wolves, bears and lynx, demonstrates that biodiversity change is not a one way street. Indeed, few would have predicted a predator renaissance in Europe 50 years ago. Yet, European society has deemed that predators are important to conserve and they are actively restoring them.


George Monbiot advocates for restoring or “rewilding” the natural world

There are emerging signs that Australians are up to the task too.

The western quoll, a species that once occurred in every mainland state (now restricted to southwestern Western Australia), has been reintroduced to the Flinders Ranges, and is reproducing.

There is growing support for ambitious projects such as the reintroduction of Tasmanian Devils onto mainland Australia, both for their own conservation and to help control invasive predators, such as red foxes and feral cats. The eastern quoll also persists in Tasmania and so their reintroduction to mainland Australia remains a possibility.

Even dingoes are being recognised for considerable conservation values, and at times, their economic benefits.

Organisations are being assembled to specifically promote and support the recovery of many of our iconic apex predators.

It is time for the public, governments and non-government organisations to capitalise on this momentum and support audacious projects that seek to rewild Australia and restore its natural glory.

Let us hope that a future not so far away will see our landscapes reinvigorated by a resurgent mammal fauna.

This article was originally published on The Conversation. (Reblogged with permission). Read the original article.

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We have more parks than ever, so why is wildlife still vanishing?

The Conversation

By Bob Pressey, James Cook University and Euan Ritchie, Deakin University

While we can never know for sure, an extraordinary number of animals and plants are threatened with extinction — up to a third of all mammals and over a tenth of all birds. And the problem is getting worse.

At the same time, we have more land and sea than ever in protected areas (“parks”) — more than 200,000 protected areas covering about 15% of the world’s land area and 3% of the oceans.

So why are protected areas making so little difference?

This is a vital question about the future of nature that should be discussed at Sydney’s World Parks Congress, beginning today.

This once-in-a-decade Congress, led by the World Conservation Union (IUCN), will be attended by thousands. A sobering reality will lie behind the excitement and networking: while protected-area systems expand, we are losing the planet’s species at an alarming rate.

One reason is that protected areas are only one of our tools, and will never do the job alone. IUCN could say, though, that it’s doing the best it can.

But another reason, more confronting for IUCN, is that protected areas tend to be in the wrong places.

Bison in Yellowstone National Park in the United States
Rich Flynn, CC BY-NC-SA

Protecting the leftovers

Just about anywhere people have looked, the majority of protected areas are residual — leftover areas of the world pushed to the margins where they least interfere with extractive activities such as agriculture, mining, or forestry.

On land, protected areas are mainly remote or high, cold, arid, steep, and infertile. Similar patterns are emerging in the sea.

Residual protected areas, by definition, make least difference to conservation.

Meanwhile, biodiversity continues to be lost in landscapes and seascapes suitable for clearing, logging, grazing, fishing, and extraction of minerals, oil, and gas.

Residual protection also gives the false appearance of progress because many people equate the number of protected areas and their extent with success.

These figures are only “good news” if they tell us about the difference these parks make to conservation. They don’t.

Failing to stop the losses

The most rigorous estimates of the difference that protected areas make are small.

By 2008, only 7% of Costa Rica’s much-lauded protected-area system would have been deforested in the absence of protection.


Sloth in Cahuita National Park, Costa Rica
Marika Lüders, CC BY-NC

Globally, in 2005, the loss of native vegetation prevented by protected areas was 3% of their extent.

These numbers get to the very purpose of protected areas. They are small because protected areas are mainly residual.

Aiming for the wrong targets

Protected areas that make little or no difference should be a major concern for IUCN, especially because targets for protection endorsed by the Convention on Biological Diversity at best obscure and at worst encourage the failure of protected areas to make a difference.

The Convention’s targets are meant to guide decisions on protected areas to 2020. The only unambiguously quantitative target (number 11) says nothing about making a difference. It aspires to 17% of land and 10% of the sea under formal protection.

The result has been a rush to proclaim large, remote protected areas where they are easiest to establish and make least difference. The story is familiar in conservation and beyond: provide a simplistic metric that implies success, and it will be manipulated to achieve high scores.

Another of the Convention’s targets (number 5) gets closer to the real purpose of protected areas, but remains problematic: “By 2020, the rate of loss of all natural habitats, is at least halved and where feasible brought close to zero, and degradation and fragmentation [are] significantly reduced.”

But there are problems here too. Before we halve the rate of loss, we need to know what the “baseline” rate of loss is — and over what period it should it be measured. Should it be measured in the past, when loss might have been slower, or now? Habitat loss also varies across the world — does that mean that reduction in loss rates of some areas can offset faster losses elsewhere?

Several kinds of tropical forests, for example, housing most of the world’s terrestrial species, are being lost rapidly. For these, even a halving of the rate of loss will mean mass extinction.

Australia setting a bad example

IUCN’s mission is hindered by recalcitrant governments.

Australia, as host of the World Parks Congress, will show off its conservation wares. The display window is less impressive than when Australia genuinely led global conservation thinking from the 1970s to 1990s.

Our protected areas on land, such as those in the host state, are strongly residual (claims of an improving trend are based on inadequate data).

Australia’s marine parks, which are directed more at satisfying total protected area than protecting threatened marine biodiversity, show other countries how not to protect the sea.


Australia is setting a bad example of how to protect our oceans
Chris Ford, CC BY-NC

And the only quantitative targets in Australia’s Strategy for the National Reserve System — for protected extent and coverage of regional ecosystems — leave plenty of scope for more parks that make little or no difference.

Not content with marginalising protection, Australian governments are weakening what’s there. Parks on land are being opened up for livestock grazing, industrial logging, mining, “conservation hunting”, and commercial development.

No-take zones in marine parks are being opened up for fishing. The Great Barrier Reef Marine Park is in jeopardy and the plan to fix it is destined to fail.

Four steps to make parks work

Here are four ways for IUCN to lead the way to parks that make a bigger difference:

  • Stop using targets that give the illusion of conservation progress. These include the number and extent of protected areas and percentages of countries, states, or regions covered. At best they will inadvertently obscure the real signal. At worst they will be used perversely to dress up residual protection.
  • Measure success as the difference protected areas make relative to no protection. This is “impact evaluation” in fields such as medicine, education, and development aid, where difference means saving and improving human lives. If saving species is also important, evaluating the impact of protected areas is essential.
  • Establish an IUCN Task Force to develop ways for evaluating the impact of protected areas, considering both biodiversity and human livelihoods. Assess the impact of current protected areas to provide lessons for management and future planning. And test approaches to setting priorities as the predictions they are.
  • Develop targets for the impact of protected areas: how much threat should be averted and how much loss should be avoided?

Ultimately, the success of conservation depends on what natural resources are left unexploited by humans so that other species can survive.

Protection that does not avoid the loss of species and ecosystems merely gives the appearance of conservation progress under exploitative business-as-usual.

Real conservation – the kind that makes a difference – depends on IUCN’s leadership. Every year of delay means irreversible, avoidable loss of biodiversity.

This article was co-authored by Dr Piero Visconti, Board Member of the European Section of the Society for Conservation Biology in Washington, D.C.

The ConversationThe authors do not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article. They also have no relevant affiliations.

This article was originally published on The Conversation. (Republished with permission). Read the original article.

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