Walruses


Dingoes found in New South Wales, but we’re killing them as ‘wild dogs’



One in four of nearly 800 animals genetically tested were pure dingo.
Michelle J Photography

Kylie M Cairns, UNSW; Brad Nesbitt, University of New England; Mathew Crowther, University of Sydney; Mike Letnic, UNSW, and Shawn Laffan, UNSW

There is a widespread belief dingoes are as good as extinct in New South Wales and nearly all dog-like animals in the wild are simply wild dogs. This belief is bolstered by legislation and policies in NSW, which have removed the word dingo and refer only to “wild dogs”.

But our research, recently published in the journal Conservation Genetics, challenges this assumption. We performed DNA ancestry testing, much like the ancestry tests available to people, on 783 wild canines killed as part of pest control measures in NSW.




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Roughly one in four of the animals we tested were pure dingoes, and most were genetically more than three-quarters dingo. Only 5 of the 783 animals we tested turned out to be feral domestic dogs with no dingo ancestry.

If it looks like a dingo, acts like a dingo and shares dingo genes… there’s a pretty good chance it’s a dingo.
Michelle J Photography, Author provided

Dingo hotspots

Studies carried out by the CSIRO in the 1980s and ‘90s examined the skulls of wild canines in southeastern Australia, and concluded they were largely hybrids of dingoes and dogs.

In NSW all wild dogs are classified as pest animals. Under the NSW Biosecurity Act 2015 all landholders have a duty to control wild dogs to minimise the risk of negative impacts on neighbouring land.

This policy requires all public and private landholders in NSW to display signs warning when poison baits have been laid to kill wild dogs.

But our DNA testing found three hotspots of high dingo ancestry within northeastern NSW: Washpool National Park; the coast north of Port Macquarie; and the Myall lakes region.

There were more pure dingoes in these areas. Despite these positive findings, dingo-dog hybridisation is still very prevalent in NSW. Three-quarters of wild animals carry some domestic dog ancestry.




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This is not entirely surprising. Domestic pet and working dogs have lived alongside dingoes for centuries. Widespread killing of dingoes also increases the risk of hybridisation because it breaks family groups apart, giving domestic dogs the opportunity to mate with dingoes. Small populations also have a higher risk of hybridisation.

1080 poison baits are affecting dingoes as well as feral dogs.
Mike Letnic

Hybridisation is generally considered detrimental to conservation because it alters the genome. In the case of dingoes, hybridisation is a problem because hybrids may be different to dingoes and “true” dingoes will eventually disappear.

While our results show dingoes still exist and their genes are predominate, their conservation will be greatly helped if we can prevent further interbreeding with domestic dogs.

Time to resurrect the dingo

Our study has important implications for both how we describe dingoes, and the future conservation of dingoes in NSW. Most of the animals labelled as wild dogs in NSW had predominantly dingo DNA, and fewer than 1% were actually feral dogs.

The term wild dog obfuscates the identity of wild animals whose genes are mostly dingo but sometimes carry dog genes. For all intents and purposes, these animals have dingo DNA, look like dingoes and behave like dingoes, and consequently should be labelled as dingoes rather than escaped pets gone wild.




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Hotspots with high dingo ancestry have significant conservation value and urgently need new management plans to ensure these pure dingo populations are protected from hybridisation. These populations could be protected by restricting the killing of dingoes in these areas and restricting access to domestic dogs on public land such as state forests.

Animals long thought to be wild dogs are actually predominantly dingoes.
Michelle J Photography, Author provided

Further ancestry testing should be conducted in more areas to determine whether there are other pockets of high dingo purity in NSW.

Undeniably, dingoes can negatively impact livestock producers, especially sheep farmers. Non-lethal strategies such as electric or exclusion fencing, and livestock guarding animals such as dogs, llamas and donkeys, may balance the need to conserve dingoes and protect vulnerable livestock.




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In some circumstances, dingoes can benefit farmers because they reduce numbers of native and feral herbivores like kangaroos, feral goats, rabbits and pigs, boosting pasture growth for livestock.

If lethal control is justified, then targeted strategies such as shooting and trapping may be more suitable in high dingo conservation areas rather than landscape-wide poison aerial baiting.

It is time to resurrect the dingo. The term dingo needs to come back into official language, and we need practical strategies for limiting dingo-dog hybridisation and protecting dingo hotspots.




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The Conversation


Kylie M Cairns, Research fellow, UNSW; Brad Nesbitt, Adjunct Research Fellow, University of New England; Mathew Crowther, Associate professor, University of Sydney; Mike Letnic, Professor, Centre for Ecosystem Science, UNSW, and Shawn Laffan, Associate professor, UNSW

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

Some animals pause their own pregnancies, but how they do it is still a mystery



Tammar wallabies are one of many species that can pause their pregnancies until the time is right.
LCAT Productions / Shutterstock

Jane Fenelon, University of Melbourne

Putting your pregnancy on pause until the time is right to give birth sounds like something out of a sci-fi novel, but for many mammals what’s known as “embryonic diapause” is an essential part of raising their young.

Although scientists have known since the 1850s that some animals have this ability, it is only now becoming clear how it could teach us valuable lessons about human pregnancy, stem cells, and cancer.

Which animals can do this?

More than 130 species of mammal can pause their pregnancies. The pause can last anywhere between a couple of days and 11 months. In most species (except some bats, who do it a little later) this happens when the embryo is a tiny ball of about 80 cells, before it attaches to the uterus.

It’s not just a single group of mammals, either. Various species seem to have developed the ability as needed to reproduce more successfully. Most carnivores can pause their pregnancies, including all bears and most seals, but so can many rodents, deer, armadillos, and anteaters.




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More than a third of the species that take a breather during gestation are from Australia, including some possums and all but three species of kangaroo and wallaby.

The record-holder for pregnancy pause time is the tammar wallaby, which has been studied extensively for its ability to put embryos on hold for up to 11 months.

Why pause pregnancy?

The main advantage to pausing pregnancy is that it separates mating and birth. There are two main ways in which animals do this.

The first way is to mate soon after giving birth, to have a backup pregnancy in case something happens to the newborn young. The stress of lactating triggers a pause that lasts during suckling, and the pregnancy restarts once the young leave.

The second way is to pause every pregnancy until the time is right (usually depending on the season). For example, minks mate around the start of March but put the embryos on pause until after the spring equinox (March 21), when the days are growing longer in their northern hemisphere homes. This ensures that the young are born in spring when conditions improve, and not in winter.

The tammar wallaby combines these two methods (suckling in the first half of the year, short days in the second) to pause for almost a year and give birth in January. This ensures the young leave the pouch the following spring instead of in the middle of a hot Australian summer.

What can we learn from diapause?

Diapause was first identified in 1854 after hunters in Europe noticed that pregnancy in roe deer seemed to last a lot longer than normal. Since then scientists have been fascinated by this process and it has helped us understand more about basic reproductive processes in all mammals.

But it took until 1950 before our knowledge of pregnancy had increased enough so that we could confirm what the hunters had observed 100 years earlier.

But how the process worked at the molecular level is still a mystery. Until recently, there seemed to be no connection between which species used it and which didn’t and there didn’t seem to be a unifying mechanism for how pregnancy was paused. Even the hormones controlling diapause are different between mammal groups.

However, research now suggests that regardless of what hormones affect the uterus, the molecular signalling between the uterus and the embryo is conserved, at least between the mouse, mink and tammar wallaby.

Furthermore, researchers in Poland paused embryos from sheep (a non-diapause species) by transferring them into a mouse uterus and then back into the sheep with no ill effects.

This indicates the potential for diapause could lie in all mammals, including humans.

So when can I pause my pregnancy?

It’s unlikely that pausing pregnancy will become the norm in humans. For starters, you’d have to know you were pregnant within five days of conceiving to match the time when most species start diapause.

Understanding how mammals pause their pregnancies does have significant implications for our understanding of how to make healthy embryos. The time when the embryo enters into diapause is the same time in IVF when an embryo is transferred into the uterus. Diapause could help us improve how we grow embryos in culture or how to recognise which is the “best” embryo to transfer.




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Diapause could also help create better stem cells and find new cancer treatments. The first stem cells ever isolated by scientists came from a mouse embryo in diapause, when the cell cycle of the embryo is arrested. Stem cells are also remarkably similar to a diapaused embryo.

So understanding how diapause works at the molecular level could lead to new therapies to halt cell division or to identify markers for tumour stem cells, which are thought to be responsible for metastasis in cancer.The Conversation

Jane Fenelon, Research fellow in monotreme and marsupial reproduction and development, University of Melbourne

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

Whales and dolphins found in the Great Pacific Garbage Patch for the first time



Adult and infant sperm whales have been spotted in the Great Pacific Garbage Patch.
Inf-Lite Teacher/Flickr, CC BY-SA

Chandra Salgado Kent, Edith Cowan University

Scientific research doesn’t usually mean being strapped in a harness by the open paratroop doors of a Vietnam-war-era Hercules plane. But that’s the situation I found myself in several years ago, the result of which has just been published in the journal Marine Biodiversity.

As part of the Ocean Cleanup’s Aerial Expedition, I was coordinating a visual survey team assessing the largest accumulation of ocean plastic in the world: the Great Pacific Garbage Patch.




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When the aircraft’s doors opened in front of me over the Pacific Ocean for the first time, my heart jumped into my throat. Not because I was looking 400m straight down to the wild sea below as it passed at 260km per hour, but because of what I saw.

This was one of the most remote regions of the Pacific Ocean, and the amount of floating plastic nets, ropes, containers and who-knows-what below was mind-boggling.

However, it wasn’t just debris down there. For the first time, we found proof of whales and dolphins in the Great Pacific Garbage Patch, which means it’s highly likely they are eating or getting tangled in the huge amount of plastic in the area.

The Great Pacific Garbage Patch

The Great Pacific Garbage Patch is said to be the largest accumulation of ocean plastic in the world. It is located between Hawaii and California, where huge ocean currents meet to form the North Pacific subtropical gyre. An estimated 80,000 tonnes of plastic are floating in the Great Pacific Garbage Patch.




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Our overall project was overseen and led by The Ocean Cleanup’s founder Boyan Slat and then-chief scientist Julia Reisser. We conducted two visual survey flights, each taking an entire day to travel from San Francisco’s Moffett Airfield, survey for around two hours, and travel home. Along with our visual observations, the aircraft was fitted with a range of sensors, including a short-wave infrared imager, a Lidar system (which uses the pulse from lasers to map objects on land or at sea), and a high-resolution camera.

Both visual and technical surveys found whales and dolphins, including sperm and beaked whales and their young calves. This is the first direct evidence of whales and dolphins in the heart of the Great Pacific Garbage Patch.

Mating green turtles in a sea of plastics.
photo by Chandra P. Salgado Kent, Author provided

Plastics in the ocean are a growing problem for marine life. Many species can mistake plastics for food, consume them accidentally along with their prey or simply eat fish that have themselves eaten plastic.

Both beaked and sperm whales have been recently found with heavy plastic loads in their stomachs. In the Philippines, a dying beaked whale was found with 40kg of plastic in its stomach, and in Indonesia, a dead sperm whale washed ashore with 115 drinking cups, 25 plastic bags, plastic bottles, two flip-flops, and more than 1,000 pieces of string in its stomach.

The danger of ghost nets

The most common debris we were able to identify by eye was discarded or lost fishing nets, often called “ghost nets”. Ghost nets can drift in the ocean for years, trapping animals and causing injuries, starvation and death.

Crew sorts plastic debris collected from the Great Pacific Garbage Patch on a voyage in July 2019.
EPA/THE OCEAN CLEANUP

Whales and dolphins are often found snared in debris. Earlier this year, a young sperm whale almost died after spending three years tangled in a rope from a fishing net.

During our observation we saw young calves with their mothers. Calves are especially vulnerable to becoming trapped. With the wide range of ocean plastics in the garbage patch, it is highly likely animals in the area ingest and become tangled in it.

It’s believed the amount of plastics in the ocean could triple over the next decade. It is clear the problem of plastic pollution has no political or geographic boundaries.




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While plastics enter the sea from populated areas, global currents transport them across oceans. Plastics can kill animals, promote disease, and harm the environment, our food sources and people.

The most devastating effects fall on communities in poverty. New research shows the Great Pacific Garbage Patch is rapidly growing, posing a greater threat to wildlife. It reinforces the global movement to reduce, recycle and remove plastics from the environment.

But to really tackle this problem we need creative solutions at every level of society, from communities to industries to governments and international organisations.

To take one possibility, what if we invested in fast-growing, sustainably cultivated bamboo to replace millions of single-use plastics? It could be produced by the very countries most affected by this crisis: poorer and developing nations.




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It is only one of many opportunities to dramatically reduce plastic waste, improve the health of our environments and people, and to help communities most susceptible to plastic pollution.The Conversation

Chandra Salgado Kent, Associate Professor, School of Science, Edith Cowan University

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

Rewild 25% of the UK for less climate change, more wildlife and a life lived closer to nature



Eduard Militaru/Unsplash, CC BY-SA

Simon Lewis, UCL

The UK’s Labour Party has pledged to offer voters a Green New Deal at the next election. This is a radical programme for decarbonising society and the economy by 2030, through phasing out fossil fuels, investing in renewable energy and creating a public works programme to build the zero-carbon infrastructure of the future.

In my recent report, A Green New Deal for Nature, I argued that giving land back to nature could be another part of this vision. Restoring forests and other natural habitats to 25% of the UK’s land surface could sequester 14% of the UK’s annual greenhouse gas emissions each year. As emissions are scaled down and these ecosystems expand, they could continue to remove much greater quantities of carbon dioxide (CO₂) in future.

Often called “natural climate solutions”, restoring forests and wetlands draws carbon down from the atmosphere and stores it in the tissue of new vegetation and soil. On a large scale, and alongside leaving fossil fuels in the ground, this could help to limit global heating to well below 2°C.

The Domesday Book of 1086 indicated forest cover of 15%, ‘but significant loss of woodland started over 4,000 years ago in prehistory’. By the beginning of the 20th century, this had dropped to 5%.
Defra

These habitats can be restored through rewilding, which means giving natural processes a helping hand by stopping the draining of peatland for example, or letting a woodland regrow. Reintroducing species that were once extinct in a region can also help ecosystems regenerate. While letting nature take care of itself isn’t appropriate in all cases, rewilding is one of the most powerful and cost-effective ways to resist climate breakdown and wildlife loss at the same time.

But what might that look like in practice?




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The “green” in the Green New Deal

For wildlife, it’s important that restored habitats are connected. Linked habitats allow plants and animals to move more easily as temperatures rise and rainfall patterns change. If species can migrate through green corridors to cooler areas, they could avoid local extinctions. This could mean a network of expanded hedgerows and woodland that criss-crosses the land, connecting wild habitats and ensuring species can migrate safely between them.

Other changes include reintroducing European beavers to flood plains to help manage flood risks. In remote places like the Scottish Highlands, wolves could return to keep herbivores in check and help woodlands rebound, increasing their long-term potential to store carbon. Rewilding instead of burning or draining carbon-rich peatlands would allow their vegetation and carbon stocks to recover. Wildlife, from insects to birds and large mammals, would have space to flourish. The UK would switch from being one of the world’s most nature-depleted countries to a green and vibrant land.

Beavers have returned to the UK’s rivers after an absence of 500 years.
Abi Warner/Shutterstock

This may sound utopian, but it’s not. The UK is a densely populated country, and with 72% of the land area used for agriculture, it might seem that there’s little room for anything else. But less than 20% of the UK is occupied by crops or dense urban communities, so 80% of it could be better managed for nature and storing carbon.

Some 45% of the UK’s land surface is given to grazing livestock. The poorest land for agricultural productivity is only farmed because of taxpayer subsidies. Meanwhile, about 13% of the UK is allocated to grouse-shooting and deer-stalking, often on degraded peatlands that are managed at huge environmental cost for the benefit of a tiny number of hunters. This land is currently of little value for food production, but it could store plenty of carbon if rewilded.




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The exact locations should be the subject of local knowledge and consultation, but reducing grazing land from 45% of the UK to 33% and returning that 12% to wild habitat could provide half of the carbon storage needed. Restoring half of the UK’s peatlands could add 6% more land, alongside protecting the 7% of the UK that is already broadleaf woodlands and wildflower meadows. Together, this would make 25% of the UK’s land a refuge for wildlife and a vast reservoir of CO₂.

The Lady Fen wetland in Norfolk was recently restored to 300 acres.
Tony Mills/Shutterstock

How can it be done?

Farm subsidies currently give £3 billion to UK farmers ever year. By some estimates, subsidies are half the income of many farmers. After Brexit, this money could be given to farmers to reward them for storing carbon and rewilding, making this more financially viable than grazing on agriculturally poor land.

Economy-wide carbon taxes could also pay for rewilding schemes, while the government could also issue green bonds to raise funds to lend to landowners, helping cover the early costs of restoring land to wild habitat.

Reducing the demand for farm produce from land will also be key to making space for nature. This means cutting down on the most inefficient use of land – farming for meat and dairy, which uses between four and 100 times the land area to produce a single gram of protein compared to beans, nuts and other plant sources. Policies which make it easier for everyone to eat food that’s healthy and sustainable – including less meat and dairy – are the final pieces of the puzzle.

Less climate change, more wildlife, and a longer life lived closer to nature. That’s a lot to gain from modest investments in how land is used in the UK.


Click here to subscribe to our climate action newsletter. Climate change is inevitable. Our response to it isn’t.The Conversation

Simon Lewis, Professor of Global Change Science at University of Leeds and, UCL

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