‘Give us a sniff, love’: giving marsupials scents from suitors helps breeding programs



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A baby eastern barred bandicoot pokes its head out of its mother’s pouch.
M. Parrott, Zoos Victoria, Author provided

Marissa Parrott, University of Melbourne

Smell is a vital part of sexual attraction for all kinds of animals (including humans). We may be able to use smell to improve breeding programs by giving the female animal a sample sniff of potential mates and letting her choose the best one before introducing them.

Our new research found female marsupials paired with the male of their choice in captive breeding programs had a higher chance of becoming pregnant, a shorter time to pregnancy and may produce healthier young.




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Curious Kids: How do we smell?


Ladies’ choice

Zoos and breeding institutions traditionally pair animals based on their relatedness and pedigree so they can manage the overall genetic health of the population. It’s expensive and often not possible to transport multiple males just to give a female some options – but if she refuses her solitary suitor when he arrives, it can cause major problems.

Our research shows that presenting the female with a range of scent samples and letting her pick her favourite dramatically increased compatibility.

This simple 10-minute test more than doubled the number of pregnancies and shortened the time to becoming pregnant in a small carnivorous marsupial, the stripe-faced dunnart.

Marissa Parrott with a captive-bred mountain pygmy-possum released to the wild.
Author provided

Using the same technique in the critically endangered mountain pygmy-possum at Healesville Sanctuary, we showed that females had significantly higher breeding success with males they liked during their choice tests. We have shown a similar effect of increasing breeding success and shortening the time to pregnancy in the endangered eastern barred bandicoot at Zoos Victoria through scent and interactions.

How are female marsupials choosing mates?

Put simply, they are following their noses. We gave females a choice of male smell and allowed her to sniff out the best mate.

In the first published study of marsupial mate choice, we found female agile antechinus chose the most genetically suitable male based on his smell. Females preferred males that were genetically dissimilar to themselves (avoiding in-breeding), but not too dissimilar (avoiding genetic out-breeding).

There is a sweet spot to female choice. If you can provide a female with a suite of males, they can choose their most compatible suitor, which in turn is likely to produce the healthiest and fittest young.

Better yet, females are choosing males compared with their own genes, so each female may like a different male, which is good for managing the overall population. However, care must be taken with sisters, as they are likely to have the same choices.




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This information is particularly helpful for global programs that have endangered species spread across different institutions and zoos, such as tree kangaroos.

In the dunnarts, we found that freezing and storing the scents of males for up to 40 days did not affect a female’s choice or interest in a scent. Thus, if you have a female tree kangaroo at Melbourne Zoo and are uncertain which male should be sent from overseas, you could freeze scents from eligible bachelors and send them to her in advance for her approval. This could reduce the stress, time and cost associated with sending males between zoos, especially if the male you sent ended up being the wrong choice!

A stripe-faced dunnart in the captive breeding colony at the University of Melbourne.
M Parrott, Author provided

But why focus on females?

In marsupials, females provide the majority of the care of the young. In the extreme case of the antechinus, all males die after mating, leaving the females with all the work raising the offspring. Thus, females are generally the choosier sex, ensuring they get the maximum benefit from appropriate mate choice.

In other species, such as the critically endangered plains wanderer whose females lay eggs and leave them with stay-at-home fathers, you may expect the male bird’s choice to be more important. He is providing the care to the growing chicks and thus will want to maximise their success through choosing the best mate.

Can people learn from the marsupial approach?

Female mate choice is a perennial issue for many humans. A study that supplied 49 women with T-shirts worn by different men found the women could sniff out the men in their genetic “sweet spot” – not too similar or dissimilar – and found those scents most attractive.

We are not so different to the endangered marsupials we are working to recover. Perhaps in the future, instead of swiping right on an image, we can be sent a palette of smells to choose a potential suitor. Instead of speed dating, could we use smell dating?




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


Certainly, when used in conservation breeding programs, allowing a female to choose her own mate can help find the best pairings, reduce the time to produce young and hopefully help produce the healthiest offspring to fight extinction for their species.The Conversation

Marissa Parrott, Reproductive Biologist, Wildlife Conservation & Science, Zoos Victoria, and Honorary Research Associate, BioSciences, University of Melbourne

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

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Guinea flowers are fierce and golden



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This guinea flower is called ‘fierce’ after its sharp, painful needles.
The Conversation/Shutterstock

Betsy Jackes, James Cook University

Welcome to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian. Read more about the series here or get in touch to pitch a plant at batb@theconversation.edu.au.


I first became interested in guinea flowers when I heard of a plant growing in Queensland’s White Mountains nicknamed “excruciating” by all who handled it, because of the pungent needle-like leaves which attached themselves to fingers and clothes.

This species is a guinea flower, now scientifically named Hibbertia ferox, meaning “fierce”. Guinea flowers grow across Australia, from the rainforest to semi-arid areas.




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Guinea flowers belong to the genus Hibbertia, which dates back to Gondwana. Members of the genus are easy to recognise, but individual species are hard to tell apart. Their brilliant yellow (or sometimes orange) flowers have petals with a notch at the apex, and they were thought to resemble the appearance of the 18th-century coin known as a golden guinea. As usual there are a couple of exceptions – at least two species have petals that lack a notch.

All too often these small shrubs and woody climbers grow in areas likely to be razed for urban sprawl or mining.



The Conversation

What we know about Hibbertia

English merchant and amateur botanist Henry Charles Andrews named the genus Hibbertia after his friend George Hibbert (1757-1837). Andrews was an artist and engraver as well as a botanist, and the first species he named was based on a plant collected around Port Jackson.

Around 200 species are recognised but there are many unnamed varieties, particularly in tropical areas. Probably the most widespread species and one of the few cultivated is the climbing guinea flower (Hibbertia scandens). It can be grown readily from cuttings but germinates slowly from seeds.

Most species have hairs covering the leaves, which can be critical for identifying a species. Under a good hand lens or a simple microscope their variety and beauty is obvious. In some species the hairs are straight. In others they are branched with arms resembling the spokes on a star, the so-called “stellate hairs”.

Some species have scales – flat, plate-like structures – on their leaves and flowers. Sometimes there are large and small scales on the one surface.

The leaves are also diverse in shape and form: some leaves are shaped like spear and thick, as in Hibbertia banksii of the eastern Cape York area, others are needle-like with margins rolled towards the lower midrib, with a sharp, blood-drawing tip, as in Hibbertia ferox.

A 1795 guinea coin from the reign of George III.
Wikipedia

The flowers are usually solitary and roughly 2cm in diameter, but in some of the northern species they grow in spikes roughly 4-5cm across.

Five sepals surround the five petals, which are broadest towards the top. The flowers usually close at night and reopen the next day.

A distinctive feature is the arrangement of the stamens (the male parts). These may be all on one side of the carpels (the structures containing the unfertilised seeds at the centre of the flower) or may form a form a ball in the centre. The number varies between species from fewer than 10 to more than 100.

Hibbertia ferox was nicknamed ‘excruciating’ because of its needle-like leaves.
Shutterstock

Floral frolics

For a plant to be involved in sex of a floral kind it needs to offer rewards for services rendered. Sometimes guinea flowers grow sterile stems, which add to the floral display and provide a food source, particularly for beetles. They are messy eaters, chewing on various plant tissues as they wander around the flower’s surface, but they do help to transfer pollen to the stigmas, or female parts (and no doubt are involved in sex with their own kind).

Guinea flowers don’t produce nectar to tempt pollinators, but people have reported them producing weak fragrance. There’s some dispute over how pleasant the smell is, with some describing it as sweet and others insisting it smells like cow dung. There have been only a couple of reports of what this smell resembles, so we need you to go and stick your nose in a freshly open flower. (Make sure to check – is the fragrance there all day or only in the morning?)

However, there is plenty of pollen. If you look closely at the anthers, those yellow sacs on the top of a thin stalk, you will see either an opening or pore at the top, or a slit down the side through which pollen can escape. Whether the marauding bug causes the pollen to spray out through the top or it accidentally falls on the bug through the slit, the bug gets dusted in pollen and then this can get brushed off on the female parts or stigma. Bees and flies are the most common bugs seen around guinea flowers.

The fruit is composed of 2-5 loosely adhering capsule-like follicles, surrounded by the five sepals, which remain and do not fall off.

Hibbertia scandens, a climbing guinea flower, is commonly known as snake vine.
Shutterstock

The fruit contains one or two seeds that are covered by a reddish coating or aril. This nutritious tissue is a valuable food source for dispersers such as ants and birds; birds have been recording spreading the seeds of Hibbertia scandens. However, in the drier areas where these plants are commonly found, ants appear to be the common dispersers.

So next time you are in the bush don’t just ignore that small shrubby plant with yellow flowers and notched petals. Stop and admire their beauty.




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Note if there are any bugs visiting and what they might be doing. Why not record their presence on iNaturalist – an app that lets us record and share your nature encounters – particularly if you are off the beaten track?


Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.. Read previous instalments here.The Conversation

Betsy Jackes, Adjunct professor, James Cook University

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

The summer bushfires you didn’t hear about, and the invasive species fuelling them



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Fire has burned through a swathe of the Tjoritja National Park.
Author provided

Christine Schlesinger, Charles Darwin University and Barry Judd, Charles Darwin University

In January 2019, fires burned across a 100-kilometre length of the iconic Tjoritja National Park in the West MacDonnell Ranges, from Ormiston Gorge nearly to the edge of Alice Springs.

These fires affected an area comparable to the recent Tasmanian fires, but attracted relatively little national attention. This is partly because the fires in Tasmania were so unusual – but we believe the fires in central Australia were just as unexpected.




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Dry lightning has set Tasmania ablaze, and climate change makes it more likely to happen again


In the past, fires of this magnitude have tended to come after heavy rain that powers the growth of native grasses, providing fuel for intense and widespread fires. But our research highlights the new danger posed by buffel grass, a highly invasive foreigner sweeping across inland Australia and able to grow fast without much water.

Far from being pristine, Tjoritja and the Western MacDonnell Ranges are now an invaded landscape under serious threat. Our changing climate and this tenacious invader have transformed fire risk in central Australia, meaning once-rare fires may occur far more often.

Buffel grass in Australia

Buffel grass is tough and fast-growing. First introduced to Australia in the 1870s by Afghan cameleers, the grass was extensively planted in central Australia in the 1960s during a prolonged drought.

Introductions of the drought-resistant plant for cattle feed and dust suppression have continued, and in recent decades buffel grass has become a ubiquitous feature of central Australian landscapes, including Tjoritja.

Buffel grass has now invaded extensive areas in the Northern Territory, Queensland, Western Australia and South Australia and is spreading into New South Wales and Victoria. It was legally recognised as a key threat in 2014, but so far only South Australia has prohibited its sale and created statewide zoning to enforce control or destruction.

Buffel grass crowds out other plants, creating effective “monocultures” – landscapes dominated by a single species. In central Australia, where Aboriginal groups retain direct, active and enduring links to Country, buffel grass makes it hard or impossible to carry out important cultural activities like hunt game species, harvest native plant materials or visit significant sites.

Buffel grass impacts on Anangu Pitjantjatjara Yankunytjatjara communities in central Australia.

But buffel grass isn’t only a threat to biodiversity and Indigenous cultural practices. In January the Tjoritja fires spread along dry river beds choked with buffel, incinerating many large old-growth trees. Much like the alpine forests of Tasmania, the flora of inland river systems has not adapted to frequent and intense fires.

We believe the ability of the fires to spread through these systems, and their increased intensity and size, can be directly attributed to buffel grass.

Fire and buffel grass

Because of the low average rainfall, widespread fires in central Australia have been rare in the recorded past, only following unusual and exceptionally high rainfall.

This extreme rain promoted significant growth of native grasses, which then provided fuel for large fires. There could be decades between these flood and fire cycles. However, since the Tjoritja (previously West MacDonnell Ranges) National Park was established in the 1990s, there have been three large-scale fires in 2001, 2011 and 2019.

What has changed? The 2001-02 and 2011-12 fires both came after heavy rainfall years. In fact, 2011 saw one of the biggest La Niña events on record.

Climate change predictions suggest that central Australia will experience longer and more frequent heatwaves. And although total annual rainfall may stay the same, it’s predicted to fall in fewer days. In other words, we’ll see heavy storms and rainfall followed by long heatwaves: perfect conditions for grass to grow and then dry, creating abundant fuel for intense fires.

The remains of a corkwood tree after an unplanned bushfire in an area heavily invaded by buffel grass near Simpsons Gap. Very few large old corkwood trees now remain in this area.
Author provided

If central Australia, and Tjoritja National Park in particular, were still dominated by a wide variety of native grasses and plants, this might not be such a problem. But buffel grass was introduced because it grows quickly, even without heavy rain.

The fires this year were extraordinary because there was no unusually high rainfall in the preceding months. They are a portent of the new future of fire in these ecosystems, as native desert plant communities are being transformed into dense near-monocultures of introduced grass.

The fuel that buffel grass creates is far more than native plant communities, and after the fire buffel grass can regenerate more quickly than many native species.

So we now have a situation in which fuel loads can accumulate over much shorter times. This makes the risk of fire in invaded areas so high that bushfire might now be considered a perpetual threat.

Changing fire threat

In spinifex grasslands, traditional Aboriginal burning regimes have been used for millennia to renew the landscape and promote growth while effectively breaking up the landscape so old growth areas are protected and large fires are prevented. Current fire management within Tjoritja “combines traditional and scientific practices”.

However, these fire management regimes do not easily translate to river environments invaded by buffel grass. These environments have, to our knowledge, never been targeted for burning by Aboriginal peoples. Since the arrival of buffel grass, there is now an extremely high risk that control burns can spread and become out-of-control bushfires.

Even when control burns are successful, the rapid regrowth of buffel grass means firebreaks may only be effective for a short time before risky follow-up burning is required. And there may no longer be a good time of year to burn.




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Our research suggests that in areas invaded by buffel grass, slow cool winter burns – typical for control burning – can be just as, or more, damaging for trees than fires in hot, windy conditions that often cause fires to spread.

Without more effective management plans and strategies to manage the changing fire threat in central Australia, we face the prospect of a future Tjoritja in which no old-growth trees will remain. This will have a devastating impact on the unique desert mountain ranges.

We need to acknowledge that invasive buffel grass and a changing climate have changed the face of fire risk in central Australia. We need a coordinated response from Australia’s federal and state governments, or it will be too late to stop the ecological catastrophe unfolding before us.


The authors acknowledge the contribution of Shane Muldoon, Sarah White, Erin Westerhuis, CDU Environmental Science and Management students, and NT Parks and Wildlife staff to the research at experimental sites and ongoing tree monitoring in central Australia.The Conversation

Christine Schlesinger, Senior Lecturer in Environmental Science and Ecology, Charles Darwin University and Barry Judd, Professor, Indigenous Social Research, Charles Darwin University

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

From Kangaroo Island to the Great Barrier Reef, the paradox that is luxury ecotourism



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The Southern Ocean Lodge on Kangaroo Island. Each new luxury ecotourism development becomes a precedent to allow future incursions.
Southern Ocean Lodge/AAP

Freya Higgins-Desbiolles, University of South Australia

Kangaroo Island, less than 130 kilometres from Adelaide, is one of Australia’s ecological jewels. Tourism Australia describes it as a “pristine wilderness”, with cliffs, beaches, wetlands and dense bushland offering protection to native animals such as penguins, sea lions, pelicans, koalas and, of course, kangaroos.

Kangaroo Island.
Wikimedia, CC BY-SA

It is a place “too good to spoil”.

Many who agree fear that new developments will do exactly that. With the state government’s approval, a tourism company wants to build two luxury tourist villages at unspoilt locations on the island’s west coast, within the protected area of the Flinders Chase National Park, the state’s second-oldest national park.

Park volunteers have gone on strike in opposition. Hundreds have rallied before South Australia’s parliament in support of “public parks, not private playgrounds”.

The issue is not unique to Kangaroo Island. Around Australia, and the world, national parks are under threat from the curious paradox of luxury tourism, which demands development in protected wilderness areas to cater for those who want to enjoy the natural environment without any interruption of their lifestyle.




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Death by a thousand cuts

My research has involved studying past development controversies on Kangaroo Island. One is Southern Ocean Lodge, a six-star ecolodge near Flinders Chase developed in the mid-2000s. Another is the Kangaroo Island Surf Music Festival, held in 2011 at Vivonne Bay, on the island’s south coast.

Southern Ocean Lodge, Kangaroo Island, South Australia.
Southern Ocean Lodge/AAP

Both cases illuminate the process by which parks authorities are pressured to support commercial tourism enterprises in their protected areas.

Park authorities never have enough funding to pay for conservation. Tourism authorities motivated by growth indicators seek to attract high-yield tourists. Luxury ecotourism is a lucrative niche. As budgets for the environment are cut, the financial incentives dangled by tourism authorities become irresistible.

It is presented as a win-win collaboration. Any single venture can be justified on the grounds that the immediate benefits outweigh the costs. But each development becomes a precedent to allow future incursions, resulting in “death by a thousand cuts”.

Elsewhere in Australia

South Australian authorities are hardly alone in accepting this faustian bargain.

In Tasmania, the federal and state governments are backing plans for a tourism development on an island in the middle of Lake Malbena in the central highlands. The lake is within the Walls of Jerusalem National Park, part of the Tasmanian Wilderness World Heritage Area.

The plan reportedly involves building three luxury huts and a helipad so six people at a time can fly in for three-night getaways at a cost of about A$4,500 each.




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In Queensland, the state government has plans to offer 60-year leases to commercial tourism operators in three national parks (the Whitsunday Islands National Park, the Great Sandy National Park and the Great Barrier Reef Marine Park). The operators will be allowed to build “eco-lodges” and offer “commercial experiences”.

An insight into what those experiences might involve is provided by The Weekend Australian Magazine, (whose readers have an average income of A$116,495).

The article “Walk this way: adventures in the great outdoors” (published 2-3 March 2019) talks of “fully supported walking experiences” with “luxury accommodations” and “premium food and wines” costing thousands of dollars, and in some cases using helicopters to access remote park sites.

Australian Walking Company

One company keen to snare the Queensland leases is the developer of the Kangaroo Island luxury tourism plan, Australian Walking Company. A director and significant shareholder in the company is Brett Godfrey, the former chief executive of Virgin Australia who is now chairman of Tourism Queensland.

All that glitters: Brett Godfrey strikes a pose to promote Virgin’s Australian operation in 2007.
Virgin Australia

Godfrey has addressed his potential conflict of interest by taking advice from the office of the Queensland Integrity Commissioner.

Nonetheless, his dual interests give an insight into the problematic nature of governments and tourism bureaucracies supporting luxury ecotourism developments in conservation areas; particularly when (as former Queensland minister for national parks Steve Dickson said in 2013), they are “looking to make money”.

Private versus public interest

The business strategy of unlocking national parks for luxury eco-tourism development risks undermining the very point of creating such parks in the first place. It pits the private interests of the wealthy against the public interest in environmental and local benefits.

It places no value on the conservation work of “friends of parks” groups, which support these parks primarily as places for conservation and secondly as publicly funded places to enjoy, learn about and connect to nature.

Catering to the luxury eco-tourist is at odds with the “wild” and undeveloped nature that conservationists and local park lovers want. You can’t get away from it all and take it all with you.

Advocates can argue that luxury eco-tourism is more sustainable because it offers high economic yield with fewer numbers. But take that argument to its logical extreme and we’ll end up with situations like that in Indonesia.

Komodo lessons

The governor of the province that includes Komodo National Park, the island home of komodo dragons, wants to increase the park’s entrance fee by 5,000%, from about US$10 to US$500. It would certainly reduce tourist numbers, but also effectively make the park off-limits to most Indonesians.

The governor, Victor Laidkodat, is apparently fine with that. “This is a rare place, only for people with money,” he has reportedly said. “Those who don’t have enough money shouldn’t come because this place is for extraordinary people.”




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This is certainly not what we want for our own national parks, turning them into private playgrounds for the privileged few.

This year is the centenary of Kangaroo Island’s Flinders Chase National Park. It’s a good time to look back and appreciate the vision that led to its establishment in 1919, and to look critically at what our vision is for the next 100 years.The Conversation

Freya Higgins-Desbiolles, Senior Lecturer in Tourism Management, University of South Australia

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

To reduce fire risk and meet climate targets, over 300 scientists call for stronger land clearing laws



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Without significant tree cover, dry and dusty landscapes can result.
Don Driscoll, Author provided

Martine Maron, The University of Queensland; Andrea Griffin, University of Newcastle; April Reside, The University of Queensland; Bill Laurance, James Cook University; Don Driscoll, Deakin University; Euan Ritchie, Deakin University, and Steve Turton, CQUniversity Australia

Australia’s high rates of forest loss and weakening land clearing laws are increasing bushfire risk, and undermining our ability to meet national targets aimed at curbing climate change.

This dire situation is why we are among the more than 300 scientists and practitioners who have signed a declaration calling for governments to restore, or better strengthen regulations to protect native vegetation.




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Land clearing laws have been contentious in several states for years. New South Wales relaxed its land clearing controls in 2017, triggering concerns over irreversible environmental damage. Although it is too early to know the impact of those changes, a recent analysis found that land clearing has increased sharply in some areas since the laws changed.

The Queensland Labor government’s 2018 strengthening of land clearing laws came after years of systematic weakening of these protections. Yet the issue has remained politically divisive. While discussing a federal inquiry into the impact of these policies on farmers, federal agriculture minister David Littleproud suggested that the strenthening of regulations may have worsened Queensland’s December bushfires.

We argue such an assertion is at odds with scientific evidence. And, while the conservation issues associated with widespread land clearing are generally well understood by the public, the consequences for farmers and fire risks are much less so.

Tree loss can increase fire risk

During December’s heatwave in northern Queensland, some regions were at “catastrophic” bushfire risk for the first time since ratings began. Even normally wet rainforests, such as at Eungella National Park inland from Mackay, sustained burns in some areas during “unprecedented” fire conditions.

There is no evidence to support the suggestion that 2018’s land clearing law changes contributed to the fires. No changes were made to how vegetation can be managed to reduce fire risk. This is governed under separate laws, which remained unaltered.

In fact, shortly after the fires, Queensland’s land clearing figures were released. They showed that in the three years to June 2018, an area equivalent to roughly 570,000 Melbourne Cricket Grounds (1,138,000 hectares) of bushland was cleared, including 284,000 hectares of remnant (old-growth) ecosystems.

Tree clearing can worsen fire risk in several ways. It can affect the regional climate. In parts of eastern Australia, tree cover reductions are estimated to have increased summer surface temperatures by up to 2℃ and southwest Western Australia by 0.4–0.8℃, reduced rainfall in southeast Australia, and made droughts hotter and longer.

Removing forest vegetation depletes soil moisture. Large, intact areas of forest typically have cooler, wetter microclimates buffered from extreme temperatures. Over time, some forest types can even become fire-resistant, but smaller patches of trees are typically drier and more flammable.

Trees also form a natural windbreak that can slow the spread of bushfires. An analysis of the 2005 Wangary fire in South Australia found that fires spread most rapidly through paddocks, rather than through areas lined with native trees.

Trends from 1978 to 2017 in the annual (July to June) sum of the daily Forest Fire Danger Index, an indicator of the severity of fire weather conditions. Positive trends, shown in the yellow to red colours, indicate increasing length and intensity of the fire weather season. Areas where there are sparse data coverage, such as central parts of Western Australia, are faded.
CSIRO/Bureau of Meteorology/State of the Climate 2018

Finally, Australia’s increasing risk of bushfire and worsening drought are driven by global climate change, to which land clearing is a major contributor.

Farmers on the frontline of environmental risk

Extensive tree clearing also leads to problems for farmers, including rising salinity, reduced water quality, and soil erosion. Governments and rural communities spend significant money and labour redressing the aftermath of excessive clearing.

Sensible regulation of native vegetation removal does not restrict existing agriculture, but rather seeks to support sustainable production. Retained trees can help deal with many environmental risks that hamper agricultural productivity, including animal health, long-term pasture productivity, risks to the water cycle, pest control, and human well-being.

Rampant tree clearing is undoing climate policy too. Much of the federal government’s A$2.55 billion Emissions Reduction Fund has gone towards tree planting. But it would take almost this entire sum just to replace the trees cleared in Queensland since 2012.




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Stopping land clearing and replanting trees could help keep Australia cool in a warmer future


In 2019, Australians might reasonably expect that our relatively wealthy and well-educated country has moved beyond a frontier-style reliance on continued deforestation, and we would do well to better acknowledge and learn lessons from Indigenous Australians with respect to their land management practices.

Yet the periodic weakening of land clearing laws in many parts of Australia has accelerated the problem. The negative impacts on industry, society and wildlife are numerous and well established. They should not be ignored.The Conversation

Martine Maron, ARC Future Fellow and Associate Professor of Environmental Management, The University of Queensland; Andrea Griffin, Senior Lecturer, School of Psychology, University of Newcastle; April Reside, Researcher, Centre for Biodiversity and Conservation Science, The University of Queensland; Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University; Don Driscoll, Professor in Terrestrial Ecology, Deakin University; Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, and Steve Turton, Adjunct Professor of Environmental Geography, CQUniversity Australia

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

A warning for wine-lovers: climate change is messing with your favourite tipple’s timing



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Record-breaking maximum temperatures are changing ripening times in Australia’s wine regions.
Shutterstock

Christopher Davies, CSIRO and Christine Bottcher, CSIRO

While the much-derided “latte set” are stereotyped as the biggest worriers about climate change, it’s the chardonnay crowd who are acutely feeling its effects.

Australia’s wine industry is both world-renowned and economically significant, with around A$5.6 billion in sales in 2016–17, and winemaking and associated tourism responsible for more than 170,000 full and part-time jobs. Statistics also show that wine consumption is now accepted as being just as dinky-di as beer drinking for the average Australian.




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However, record-breaking daily maximum temperatures, warmer than average overnight temperatures, and increasingly erratic weather patterns are playing havoc with the way wine grapes grow and ripen. This has knock-on effects for Australian grape growers, wine producers and consumers.

Climate in the vineyard hits the cellar and the store shelf

Most of Australia’s wine regions have experienced rising average daily temperatures. One effect is changes to ripening times, which has compressed the harvesting season and given wine-makers a crucial logistical headache.

Traditionally, white grape varieties would generally reach optimum ripeness before red ones. While all grapes tend to ripen faster as temperatures rise, this effect is more pronounced for later-ripening varieties (for example Shiraz and Cabernet Sauvignon) than earlier ripening varieties (for example Chardonnay and Riesling).

Australian winegrape varieties are becoming ready for harvest simultaneously.
Shutterstock

The old process of staggered harvesting times for red and white grape varieties was efficient, allowing the winery’s capacity to be used in sequence for different varieties. Now that different varieties are ripening at the same time, vineyards and wineries will have to make tough choices about which grapes to prioritise, and which ones to leave until later, resulting in inferior wine. Alternatively, they could take the expensive decision to increase production capacity by investing in more infrastructure such as fermenters and stainless steel tanks.




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Perhaps you’re thinking that you, the savvy wine drinker, are unaffected by the difficulties faced by winemakers in the vineyards and wineries far away. Unfortunately this isn’t so. Harvesting grapes when they are not at optimal ripeness to solve the logistical problems of processing can lead to lower-value wine.

The fact is that this new reality is costing everyone – grape-growers, winemakers and consumers alike.

And just in case you think that the simple answer is changing Australia’s cultured palates back to beer, think again. Hop production is being hit just as hard by climate change.

Help is at hand

Fortunately, these are problems we hope to tackle. CSIRO recently announced a five-year research partnership with Wine Australia, and one of the projects aims to adjust wine grape ripening to suit a changing climate.

We hope to do it by studying plant growth regulators (PGRs) – molecules that are used by the plant to control and coordinate development. We are using a class of PGRs called auxins, first studied in grass seedlings by Charles Darwin in the 1880s, that have important roles in vine growth, and the timing of grape growth and ripening.

Plant growth regulators can help control ripening times.
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By spraying these compounds onto vines and grapes shortly before ripening, auxins can potentially be used to influence the timing of this process and therefore harvest date. They are already used in other horticultural crops, such as to control fruit drop in apples and pears.

Applying very small amounts of auxin can delay grape ripening, and therefore harvest timing, by up to four weeks (Davies et al., 2015, J Ag Food Chem 63: 2137-2144). This treatment works for red and white varieties in hot or cool climates, and is safe, cheap and easy to apply.

The flavour and aroma of wines made from ripening-delayed grapes is largely indistinguishable from wines made from untreated fruit harvested at the same sugar level, up to a month earlier. An exciting exception is that, in Shiraz, auxin-induced ripening delay can be used to increase the concentration of rotundone, the compound responsible for this variety’s popular peppery notes.




Read more:
State of the Climate 2018: Bureau of Meteorology and CSIRO


Work is currently under way to fine-tune spray formulations and application times. The aim is to release a commercially available product within the next five years.

This kind of solution will be vital for the sustainable, economical production of high-quality wines from existing grape varieties in established wine growing regions. We hope it will ensure you can enjoy your favourite drop for many years to come.The Conversation

Christopher Davies, Team Leader, CSIRO and Christine Bottcher, Research scientist, CSIRO

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