Spring is here and wattles are out in bloom: a love letter to our iconic flowers



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Gregory Moore, University of Melbourne

Spring has arrived, and all over the country the hills and riversides are burnished with the green and gold of Australian wattles, all belonging to the genus Acacia.

It’s a spectacular sight, but not a surprising one as there are about 1,000 Australian species in the Acacia genus ranging from very small shrubs to tall, longed-lived trees. They occur in ecosystems from the arid inland to the wet forests of the east coast.




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Wattles have been widely used by Indigenous people for millenia, and celebrated by “Wattle Day” on September 1 for more than a century.

But their lineage may be much older. Australian wattles have relatives in Africa, South America, India and parts of Southeast Asia. This distribution suggests the wattles may have originated in Gondwana before the super-continent fragmented about 180 million years ago.

So let’s take a closer look at what makes these iconic flowers so special.

Wattle on a cloudy day
Wattle can always brighten a dreary day.
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Don’t blame wattles for your hay fever

Not everyone welcomes the wattles’ golden blooms — many blame wattle pollen for their hay fever or asthma.

However, many species of wattle have aggregated pollen, which means it’s very heavy and tends to fall straight to ground. You have to be virtually under the plant for it to affect you.

They can cause trouble, but it’s more likely your allergy is due to some other inconspicuous plant, such as grass, that you haven’t noticed compared to the bright yellow of the wattles. It’s worth having an allergy test.




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While a majority of wattles flower in spring and summer, a significant group — such as the sunshine wattle (A. botrycephala), Gawler Range wattle (A. iteaphylla) and flax wattle (A linifolia) — flowers in autumn and winter. This can give the impression in some places that they’re flowering year-round.

What’s more, many species are hardy, and they can help in the process of taking nitrogen from the air and adding to the soil. That means they can be very handy in ancient, nutrient-poor Australian soils.

A mulga in the Australian desert
Mulga grows over about 20% of our continent.
Mark Marathon/Wikimedia, CC BY-SA

Many of the smaller shrub wattles may live for only a decade or so, but some, such as mulga (Acacia aneura) can live for centuries and are crucial to the viability and stability of arid inland ecosystems. They can have surprisingly large and deep root systems for such small shrubs or trees. This is to obtain water, but also binds the soil.

However, mulga-munching horses, cattle and other feral grazers threaten the persistence of mulga-dominated communities. If mulga and other inland Acacia species are lost, the soils can become loose and mobile, which results in stable productive land becoming desert.

By any other name

In the early 2000s, there was fierce debate among plant taxonomists about how closely the African and Australian species were related.

The name “Acacia” rightly belonged to the African group, but because there were so many Australian species that would need to be renamed, Australia was allowed to keep the name “Acacia” in 2011 — much to the chagrin of foreign taxonomists.

This resulted in the genus being divided. Australian wattles stayed as Acacia, but African wattles are now in the genera Vachellia or Senegalia, and those from the middle Americas (around Mexico) are Acaciella and Mariosousa.

The different names reflect long, separate histories and different ecological characteristics. (The name changes rankle still with taxonomists!)

Close-up of black wattle flowers
Black wattle is a pest overseas.
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There are also weedy wattles in Australia and elsewhere. Many of us know from hard experience that the splendid ornamental tree, Cootamundra wattle (Acacia baileyiana), can become a weed if it grows outside its very restricted natural range in New South Wales. And Australia’s black wattle (A. mearnsii) is a significant weed in other parts of the world.

It can come as a bit of a blow to know Australia’s floral emblem, golden wattle (A. pycnantha), can be weedy both at home and when it travels abroad (perhaps like some Australians).




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Interestingly, most of the Australian wattles lack thorns, unlike their relatives in Africa. In Africa, thorns protect the plants from large mammalian grazers such as giraffes.

Ants love wattles, too

If you don’t like ants, it might be worth checking which species of wattle you have in your backyard, or intend to buy.

Many wattles have a very special relationship with some insects. In Central America, ants penetrate the thorns of Bulls Horn wattle trees and establish their colonies. They then defend the tree against other insects, and if branches of another tree touch the host tree, the ants will cause such damage that the other tree will die back.

There are more than 1,000 species of wattle in the Acacia genus.
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In Australia, the relationship between ants and wattles is based on food. The hard wattle seeds have a tasty and oil-rich outgrowth called an “aril”, which is irresistible to some ant species.

The ants harvest the seeds and take them back to their nest, where they’re safe from other hungry grazers until it is damaged by fire or flood and the seeds germinate.




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Some wattles, the mulga among them, have little glands at the base of their phyllodes (the modified leaf stalks). These glands secrete a form of sugary syrup that attracts feeding ants. These ants may also protect host trees or perhaps leave the flowers alone to allow a greater seed set to grow.

It’s clear wattles have a lot going for them. They are diverse in number, habit, size, longevity and flowering season — there’s a wattle for every occasion. For all of these great traits, it’s still that green and gold that endears them to Australians.The Conversation

Gregory Moore, Doctor of Botany, University of Melbourne

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

Climate explained: are consumers willing to pay more for climate-friendly products?



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Gary Mortimer, Queensland University of Technology


CC BY-ND

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz


I’m seeing quite a few “climate-friendly” products at the supermarket. Are consumers willing to pay more for these? And how can we encourage people to make good choices?

Shoppers once selected grocery products based simply on price or brand, but now attributes such as “climate-friendly” or “eco-friendly” are part of the consideration.

The latest IAG New Zealand Ipsos poll found almost four out of five people (79%) say climate change is an important issue for them, the same number as last year’s poll.

An international study of 20,000 customers by grocery brand giant Unilever identified one in three (33%) people were choosing to buy from brands they believe are doing environmental good.




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But research continues to show few consumers who report positive attitudes toward eco-friendly products actually follow through with their wallets.

Green, eco-friendly, climate-friendly products — confused?

Colloquially, use of the word “green” is applied broadly to almost everything related to benefiting the environment, from production and transportation to architecture and even fashion.

Eco-friendly isn’t quite so broad and defines products or practices that do not harm the Earth’s environment.

Climate-friendly defines products that reduce damage specifically to the climate.

All these terms are used in labelling to make us feel good if we buy products claimed to minimise harm to the planet and the environment.

Some brands are even moving beyond simply eco-friendly and now seek to claim their products are climate-neutral.

A shop with the words climate friendly toys written on the door.
Even toys can get the climate-friendly treatment.
Flickr/Justin Hall, CC BY

On Earth Day 2020, the organisation Climate Neutral — an independent non-profit organisation working to decrease global carbon emissions — confirmed 103 brands had completed its certification process in 2020 and 50 other brands were still in the process.

Who says it’s up to standard?

While companies are increasingly using environmental claims to appeal to consumers, they also attract greater scrutiny.

Concerned about allegations of greenwashing — claiming a product is green when it’s not — many brands are turning to organisations such as Climate Neutral, Foundation Myclimate and members of the Global Ecolabelling Network to legitimise their claims.

For example, the climatop label certifies products that generate significantly less greenhouse gas than comparable products. The carbon footprints of the certified products are based on international standards (ISO 14040) and verified by an independent expert.

Environmental Choice New Zealand is the official environmental label body that awards certificates and lists environmentally friendly products for green homes or businesses. Products must meet similar standards (ISO 14020 and ISO 14024). Good Environmental Choice Australia is a similar organisation.

A willingness to pay for eco-friendly products

For years, researchers have examined climate-oriented consumption to see if it wins people’s support.

Reports such as Nielsen Insights suggest the majority (73%) of consumers would change their consumption habits to reduce their impact on the environment, and almost half (46%) would switch to environmentally friendly products.

But the results should be interpreted cautiously. As US psychologist Icek Ajzen wrote:

Actions, then, are controlled by intentions, but not all intentions are carried out …

Consumer concern about the environment does not readily translate into the purchase of environmentally friendly products. Commercial research says 46% of consumers are more inclined to buy a product if it is eco-friendly. But nearly 60% are unwilling to pay more money for that eco-friendly product.

Academic research has consistently identified this gap between purchase intentions and behaviours. Hence, despite environmental concern and the positive attitude of customers towards sustainability and green products, it’s estimated the market share of green products will reach only 25% of store sales by 2021.

Ultimately, the research that evaluates consumers’ willingness to pay more for green products has been mixed.

For example, one study found Spanish consumers were willing to pay 22–37% more for green products, but Japanese consumers were only willing to pay 8–22% more for green products.

Why green products cost more

From procuring raw materials to shipping the final product, almost all steps of the manufacturing and production process of eco-friendly products cost more than traditional products.

There are several reasons for this. Sustainable materials cost more to grow and manufacture, reputable third-party certifications add further costs and using organic materials is more expensive than alternatives such as mass-produced chemicals.

Simple economies of scale also impact on price. While the demand for such products remains low, the price remains high. More demand would mean more production and lower unit price costs.

As economists say, as price lowers, our willingness and ability to buy an item increase.

The nudge to change behaviour

In a free market economy, it is very difficult to force people to pay more for products. But brands can “nudge” consumers towards more eco-friendly products.

Nudge theory is used to understand how people think, make decisions and behave. It can be used to help people improve their thinking and decisions.




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Studies show eco-friendly logos and labels can be used to nudge consumers toward sustainable fashion, food consumption and eco-friendly offerings.

So while not all consumers will pay more for green “climate-friendly” products despite the best of intentions, we can slowly nudge them to make better choices for the planet.The Conversation

Gary Mortimer, Professor of Marketing and Consumer Behaviour, Queensland University of Technology

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

Does Australia really have the deadliest snakes? We debunk 6 common myths



A red-bellied black snake
Damian Michael, Author provided

Damian R. Michael, Charles Sturt University; Dale Nimmo, Charles Sturt University, and Skye Wassens, Charles Sturt University

As we settle into spring and temperatures rise, snakes are emerging from their winter hideouts to bask in the sun. But don’t be alarmed if you spot one, it’s hard to imagine a more misunderstood group of animals than snakes.

Our interactions with snakes are conversation starters, with yarns told and retold. But knowing what’s fact and fiction gets harder with each retelling.




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As is so often the case with wildlife, the myths pale in comparison to what science has shown us about these incredible creatures. So let’s debunk six misconceptions we, as wildlife ecologists, often hear.

A snake warning sign
With snakes on the move this season, people and pets are more likely to spot them.
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1. Black snakes and blue tongue lizards keep brown snakes away

This is a common old wives’ tale in southern Australia. The myth goes that if you see a red-bellied black snake or a blue-tongue lizard on your property, you’re unlikely to see the highly venomous brown snake, because black snakes keep brown snakes at bay.

This myth probably originates from observations of black snakes eating brown snakes (which they do).

But it’s not one-way traffic. There are many reported examples of brown snakes killing black snakes, too. Overall, no scientific evidence suggests one suppresses the other.

There is also no evidence blue-tongue lizards prey upon or scare brown snakes. In fact, many snakes feed on lizards, including brown snakes which, despite a preference for mammal prey as adults, won’t hesitate to have a blue tongue for lunch.

2. Snakes are poisonous

While the term poisonous and venomous are often used interchangeably, they mean quite different things. If you eat or ingest a toxic plant or animal, it’s said to be poisonous, whereas if an animal stings or bites you and you get sick, it’s venomous.




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Venom is a specialised type of poison that has evolved for a specific purpose. For venom to work, it needs a wound to enter the body and into the bloodstream. Snakes, therefore, are generally venomous, not poisonous.

But there are exceptions. For example, the American garter snake preys on the rough-skinned newt which contains a powerful toxin.

A black and red garter snake.
The toxins from the rough-skinned newt can stay in a garter snake’s liver for up to a month.
Steve Jurvetson/Wikimedia, CC BY

The newt’s toxin accumulates in the snake’s liver, and effectively makes this non-venomous snake species poisonous if another animal or human eats it. Remarkably, these snakes can also assess whether a given newt is too toxic for them to handle, and so will avoid it.

3. Australia has the deadliest snakes in the world

Approximately 20% of the world’s 3,800-plus snake species are venomous. Based on the median lethal dose — the standard measurement for how deadly a toxin is — the Australian inland taipan is ranked number one in the world. Several other Australian snakes feature in the top 10. But does that make them the deadliest?

It depends on how you define “deadly”. Death by snake bite in Australia is very uncommon, with just two per year, on average, compared to 81,000-138,000 deaths from snakes annually worldwide.




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If we define “deadly snakes” as those responsible for killing many people, then the list would be topped by snakes such as the Indian cobra, common krait, Russell’s viper and the saw-scaled viper, which occur in densely populated parts of India and Asia.

A lack of access to antivenoms and health care contribute substantially to deaths from snake bites.

An Indian cobra upright on a log
Indian cobra’s are one of the deadliest snakes in the world.
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4. Snakes have poor eyesight

Compared to other reptiles, such as monitor lizards, most snakes have poor eyesight, especially species that are active at night or burrow in soil.

However, snakes that are active by day and feed on fast-moving prey have relatively good vision.

One study in 1999 showed people are less likely to encounter eastern brown snakes when wearing clothing that contrasted with the colour of the sky, such as dark clothing on a bright day. This suggests they can see you well before you see them.

Some snakes such as the American coachwhip can even improve their eyesight when presented with a threat by constricting blood vessels in the transparent scale covering the eye.

A sea snake dives underwater
An olive sea snake can actually detect light through their tail.
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And then there’s the olive sea snake, whose “phototactic tails” can sense light, allowing them to retract their tails under shelter to avoid predation.

5. Young snakes are more dangerous than adults

This myth is based on the idea juvenile snakes can’t control the amount of venom they inject. No evidence suggests this is true.




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However, research shows the venom of young and old snakes can differ. A 2017 study showed the venom of young brown snakes is different to adults, probably to facilitate the capture of different types of prey: young brown snakes feed on reptiles, whereas adult brown snakes predominantly feed on mammals.

But it’s not just age — venom toxicity can vary among individuals of the same population, or among populations of the same species.

A black snake with white stripes on a rock.
Bandy Bandy (Vermicella annulata). Defensive behaviours are often misinterpreted as aggression.
Damian Michael, Author provided

6. Snake are aggressive

Perhaps the most pervasive myth about snakes is they’re aggressive, probably because defensive behaviours are often misinterpreted.

But snakes don’t attack unprovoked. Stories of snakes chasing people are more likely cases where a snake was attempting to reach a retreat site behind the observer.

When threatened, many snakes give a postural warning such as neck flaring, raising their head off the ground, and opening their mouths, providing clear signals they feel threatened.

It’s fair to say this approach to dissuade an approaching person, or other animal, works pretty well.

Rhesus macaques display more fearful behaviour when confronted with snakes in a striking pose compared to a coiled or elongated posture. And showing Japanese macaques images of snakes in a striking posture sets of a flurry of brain activity that isn’t evoked when they’re shown images of snakes in nonthreatening postures.




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The same is true for humans. Children and adults detect images of snakes in a striking posture more rapidly than a resting posture. And a study from earlier this year found human infants (aged seven to 10 months) have an innate ability to detect snakes.

Snakes are amazing, but shouldn’t be feared. If you encounter one on a sunny day, don’t make sudden movements, just back away slowly. Never pick them up (or attempt to kill them), as this is often when people are bitten.The Conversation

Damian R. Michael, Senior research fellow, Charles Sturt University; Dale Nimmo, Associate Professor in Ecology, Charles Sturt University, and Skye Wassens, Associate Professor in Ecology, Charles Sturt University

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