Destroying vegetation along fences and roads could worsen our extinction crisis — yet the NSW government just allowed it

Euan Ritchie, Deakin University; Ben Moore, Western Sydney University; Jen Martin, The University of Melbourne; Mark Hall, Western Sydney University; Megan C Evans, UNSW, and Ross Crates, Australian National UniversityWhat do koalas, barking owls, greater gliders, southern rainbow skinks, native bees, and regent honeyeaters all have in common? Like many native species, they can all be found in vegetation along fences and roadsides outside formal conservation areas.

They may be relatively small, but these patches and strips conserve critical remnant habitat and have disproportionate conservation value worldwide. They represent the last vestiges of once-expansive tracts of woodland and forests, long lost to the chainsaw or plough.

And yet, the NSW government last week made it legal for rural landholders to clear vegetation on their properties, up to 25 metres from their property boundaries, without approval. This radical measure is proposed to protect people and properties from fires, despite the lack of such an explicit recommendation from federal and state-based inquiries into the devastating 2019-20 bushfires.

This is poor environmental policy that lacks apparent consideration or justification of its potentially substantial ecological costs. It also gravely undermines the NSW government’s recent announcement of a plan for “zero extinction” within the state’s national parks, as the success of protected reserves for conservation is greatly enhanced by connection with surrounding “off-reserve” habitat.

Small breaks in habitat can have big impacts

A 25m firebreak might sound innocuous, but when multiplied by the length of property boundaries in NSW, the scale of potential clearing and impacts is alarming, and could run into the hundreds of thousands of kilometres.

Some plants, animals and fungi live in these strips of vegetation permanently. Others use them to travel between larger habitat patches. And for migratory species, the vegetation provides crucial refuelling stops on long distance journeys.

For example, the roadside area in Victoria’s Strathbogie Ranges shown below is home to nine species of tree-dwelling native mammals: two species of brushtail possums, three species of gliders (including threatened greater gliders), common ringtail possums, koalas, brush-tailed phascogales, and agile antenchinus (small marsupials).

Roadside and fenceline vegetation is often the only substantial remnant vegetation remaining in agricultural landscapes. This section, in northeast Victoria’s Strathbogie Ranges, running north to south from the intersection, is home to high arboreal mammal diversity, including the threatened greater glider.
Google Earth

Many of these species depend on tree hollows that can take a hundred years to form. If destroyed, they are effectively irreplaceable.

Creating breaks in largely continuous vegetation, or further fragmenting already disjointed vegetation, will not only directly destroy habitat, but can severely lower the quality of adjoining habitat.

This is because firebreaks of 25m (or 50m where neighbouring landholders both clear) could prevent the movement and dispersal of many plant and animal species, including critical pollinators such as native bees.

An entire suite of woodland birds, including the critically endangered regent honeyeater, are threatened because they depend on thin strips of vegetation communities that often occur inside fence-lines on private land.

Ecologically-sensitive fence replacement in regent honeyeater breeding habitat.
Ross Crates

For instance, scientific monitoring has shown five pairs of regent honeyeaters (50% of all birds located so far this season) are nesting or foraging within 25m of a single fence-line in the upper Hunter Valley. This highlights just how big an impact the loss of one small, private location could have on a species already on the brink of extinction.

But it’s not just regent honeyeaters. The management plan for the vulnerable glossy black cockatoo makes specific recommendation that vegetation corridors be maintained, as they’re essential for the cockatoos to travel between suitable large patches.

Native bee conservation also relies on the protection of remnant habitat adjoining fields. Continued removal of habitat on private land will hinder chances of conserving these species.

Glossy black cockatoos rely on remnant patches of vegetation.
Shutterstock

Disastrous clearing laws

The new clearing code does have some regulations in place, albeit meagre. For example, on the Rural Fire Service website, it says the code allows “clearing only in identified areas, such as areas which are zoned as Rural, and which are considered bush fire prone”. And according to the RFS boundary clearing tool landowners aren’t allowed to clear vegetation near watercourses (riparian vegetation).

Even before introducing this new code, NSW’s clearing laws were an environmental disaster. In 2019, The NSW Audit Office found:

clearing of native vegetation on rural land is not effectively regulated [and] action is rarely taken against landholders who unlawfully clear native vegetation.

The data back this up. In 2019, over 54,500 hectares were cleared in NSW. Of this, 74% was “unexplained”, which means the clearing was either lawful (but didn’t require state government approval), unlawful or not fully compliant with approvals.

Landholders need to show they’ve complied with clearing laws only after they’ve already cleared the land. But this is too late for wildlife, including plant species, many of which are threatened.

Landholders follow self-assessable codes, but problems with these policies have been identified time and time again — they cumulatively allow a huge amount of clearing, and compliance and enforcement are ineffective.

Vegetation along roadsides and close to fences can be critical habitat for greater gliders.

We also know, thanks to various case studies, the policy of “offsetting” environmental damage by improving biodiversity elsewhere doesn’t work.

So, could the federal environment and biodiversity protection law step in if habitat clearing gets out of hand? Probably not. The problem is these 25m strips are unlikely to be referred in the first place, or be considered a “significant impact” to trigger the federal law.

The code should be amended

Nobody disputes the need to keep people and their assets safe against the risks of fire. The code should be amended to ensure clearing is only permitted where a genuinely clear and measurable fire risk reduction is demonstrated.

Many native bees, like this blue-banded bee (*Amegilla* sp.), will use the nesting and foraging resources available in remnant vegetation patches.
Michael Duncan

Granting permission to clear considerable amounts of native vegetation, hundreds if not thousands of metres away from homes and key infrastructure in large properties is hard to reconcile, and it seems that no attempt has been made to properly justify this legislation.

We should expect that a comprehensive assessment of the likely impacts of a significant change like this would inform public debate prior to decisions being made. But to our knowledge, no one has analysed, or at least revealed, how much land this rule change will affect, nor exactly what vegetation types and wildlife will likely be most affected.

A potentially devastating environmental precedent is being set, if other regions of Australia were to follow suit. The environment and Australians deserve better.

Clarification: some text has been added to clarify the land cleared is on the landowner’s property, not outside their property boundary

Euan Ritchie, Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University; Ben Moore, Senior Lecturer in Ecology, Hawkesbury Institute for the Environment, Western Sydney University; Jen Martin, Leader, Science Communication Teaching Program, The University of Melbourne; Mark Hall, Postdoctoral research fellow, Hawkesbury Institute for the Environment, Western Sydney University; Megan C Evans, Lecturer and ARC DECRA Fellow, UNSW, and Ross Crates, Postdoctoral fellow, Australian National University

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

Climate change is testing the resilience of native plants to fire, from ash forests to gymea lilies

One year following the 2019/20 fires, this forest has been slow to recover.
Rachael Nolan, CC BY-NC-ND

Rachael Helene Nolan, Western Sydney University; Andrea Leigh, University of Technology Sydney; Mark Ooi, UNSW; Ross Bradstock, University of Wollongong; Tim Curran, Lincoln University, New Zealand; Tom Fairman, The University of Melbourne, and Víctor Resco de Dios, Universitat de LleidaGreen shoots emerging from black tree trunks is an iconic image in the days following bushfires, thanks to the remarkable ability of many native plants to survive even the most intense flames.

But in recent years, the length, frequency and intensity of Australian bushfire seasons have increased, and will worsen further under climate change. Droughts and heatwaves are also projected to increase, and climate change may also affect the incidence of pest insect outbreaks, although this is difficult to predict.

How will our ecosystems cope with this combination of threats? In our recently published paper, we looked to answer this exact question — and the news isn’t good.

We found while many plants are really good at withstanding certain types of fire, the combination of drought, heatwaves and pest insects may push many fire-adapted plants to the brink in the future. The devastating Black Summer fires gave us a taste of this future.

Examples of fire-adapted plants: prolific flowering of pink flannel flowers (upper left), new foliage resprouting on geebung (upper right), seed release from a banksia cone (lower left), and an old man banksia seedling (lower right).
Rachael Nolan

What happens when fires become more frequent?

Ash forests are one of the most iconic in Australia, home to some of the tallest flowering plants on Earth. When severe fire occurs in these forests, the mature trees are killed and the forest regenerates entirely from the seed that falls from the dead canopy.

These regrowing trees, however, do not produce seed reliably until they’re 15 years old. This means if fire occurs again during this period, the trees will not regenerate, and the ash forest will collapse.

This would have serious consequences for the carbon stored in these trees, and the habitat these forests provide for animals.

Southeast Australia has experienced multiple fires since 2003, which means there’s a large area of regrowing ash forests across the landscape, especially in Victoria.

The Black Summer bushfires burned parts of these young forests, and nearly 10,000 football fields of ash forest was at risk of collapse. Thankfully, approximately half of this area was recovered through an artificial seeding program.

Ash to ashes: On the left, unburned ash forest in the Central Highlands of Victoria; on the right, ash forest which has been burned by a number of high severity bushfires in Alpine National Park. Without intervention, this area will no longer be dominated by ash and will transition to shrub or grassland.
T Fairman

What happens when fire seasons get longer?

Longer fire seasons means there’s a greater chance species will burn at a time of year that’s outside the historical norm. This can have devastating consequences for plant populations.

For example, out-of-season fires, such as in winter, can delay maturation of the Woronora beard-heath compared to summer fires, because of their seasonal requirements for releasing and germinating seeds. This means the species needs longer fire-free intervals when fires occur out of season.

The iconic gymea lily, a post-fire flowering species, is another plant under similar threat. New research showed when fires occur outside summer, the gymea lily didn’t flower as much and changed its seed chemistry.

While this resprouting species might persist in the short term, consistent out-of-season fires could have long-term impacts by reducing its reproduction and, therefore, population size.

Out-of-season fires could have long-term impacts on gymea lilies.
Shutterstock

When drought and heatwaves get more severe

In the lead up to the Black Summer fires, eastern Australia experienced the hottest and driest year on record. The drought and associated heatwaves triggered widespread canopy die-off.

Extremes of drought and heat can directly kill plants. And this increase in dead vegetation may increase the intensity of fires.

Another problem is that by coping with drought and heat stress, plants may deplete their stored energy reserves, which are vital for resprouting new leaves following fire. Depletion of energy reserves may result in a phenomenon called “resprouting exhaustion syndrome”, where fire-adapted plants no longer have the reserves to regenerate new leaves after fire.

Therefore, fire can deliver the final blow to resprouting plants already suffering from drought and heat stress.

Drought stressed eucalypt forest in 2019.
Rachael Nolan

Drought and heatwaves could also be a big problem for seeds. Many species rely on fire-triggered seed germination to survive following fire, such as many species of wattles, banksias and some eucalypts.

But drought and heat stress may reduce the number of seeds that get released, because they limit flowering and seed development in the lead up to bushfires, or trigger plants to release seeds prematurely.

For example, in Australian fire-prone ecosystems, temperatures between 40℃ and 100℃ are required to break the dormancy of seeds stored in soil and trigger germination. But during heatwaves, soil temperatures can be high enough to break these temperature thresholds. This means seeds could be released before the fire, and they won’t be available to germinate after the fire hits.

Heatwaves can also reduce the quality of seeds by deforming their DNA. This could reduce the success of seed germination after fire.

Burnt banksia — Many native plants, such as banksia, rely on fire to germinate their seeds.
Shutterstock

What about insects? The growth of new foliage following fire or drought is tasty to insects. If pest insect outbreaks occur after fire, they may remove all the leaves of recovering plants. This additional stress may push plants over their limit, resulting in their death.

This phenomenon has more typically been obverved in eucalypts following drought, where repeated defoliation (leaf loss) by pest insects triggered dieback in recovering trees.

When threats pile up

We expect many vegetation communities will remain resilient in the short-term, including most eucalpyt species.

But even in these resilient forests, we expect to see some changes in the types of species present in certain areas and changes to the structure of vegetation (such as the size of trees).

Resprouting eucalypts, one year on following the 2019-2020 bushfires.
Rachael Nolan

As climate change progresses, many fire-prone ecosystems will be pushed beyond their historical limits. Our new research is only the beginning — how plants will respond is still highly uncertain, and more research is needed to untangle the interacting effects of fire, drought, heatwaves and pest insects.

We need to rapidly reduce carbon emissions before testing the limits of our ecosystems to recover from fire.

Rachael Helene Nolan, Postdoctoral research fellow, Western Sydney University; Andrea Leigh, Associate Professor, Faculty of Science, University of Technology Sydney; Mark Ooi, Senior Research Fellow, UNSW; Ross Bradstock, Emeritus professor, University of Wollongong; Tim Curran, Associate Professor of Ecology, Lincoln University, New Zealand; Tom Fairman, Future Fire Risk Analyst, The University of Melbourne, and Víctor Resco de Dios, Profesor de Incendios y Cambio Global en PVCF-Agrotecnio, Universitat de Lleida

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

The daily dance of flowers tracking the sun is more fascinating than most of us realise

Gregory Moore, The University of MelbourneWhen I was a child, I was intrigued by the Queensland box (Lophostemon confertus) growing in our backyard. I noticed its leaves hung vertical after lunch in summer, and were more or less horizontal by the next morning.

This an example of heliotropism, which literally means moving in relation to the sun. We can see it most clearly as spring arrives and various species burst into flower — you might even get the feeling that some flowers are watching you as they move.

Many of us probably first got to know of heliotropism at home, kindergarten or primary school by watching the enormous yellow and black flowering heads of aptly name sunflowers, which moved as they grew.

These flowers track the course of the sun spectacularly on warm and sunny, spring or summer days. Sometimes they move through an arc of almost 180⁰ from morning to evening.

So with the return of sunny days and flowers in full bloom this season, let’s look at why this phenomenon is so interesting.

The mechanics of tracking the sun

A number flowering species display heliotropism, including alpine buttercups, arctic poppies, alfalfa, soybean and many of the daisy-type species. So why do they do it?

This is *Heliotropium arborescens*, named for its heliotropism. They were very popular in gardens a century or more ago, but have fallen from favour as they can be poisonous and weedy.
Shutterstock

Flowers are really in the advertising game and will do anything they can to attract a suitable pollinator, as effectively and as efficiently as they can. There are several possible reasons why tracking the sun might have evolved to achieve more successful pollination.

By tracking the sun, flowers absorb more solar radiation and so remain warmer. The warmer temperature suits or even rewards insect pollinators that are more active when they have a higher body temperature.

Optimum flower warmth may also boost pollen development and germination, leading to a higher fertilisation rate and more seeds.

So, the flowers are clearly moving. But how?

For many heliotropic flowering species, there’s a special layer of cells called the pulvinus just under the flower heads. These cells pump water across their cell membranes in a controlled way, so that cells can be fully pumped up like a balloon or become empty and flaccid. Changes in these cells allow the flower head to move.

Venus fly trap — Fly traps have somewhat similar mechanics to heliotropism.
Shutterstock

When potassium from neighbouring plant cells is moved into the cells of the pulvinus, water follows and the cells inflate. When they move potassium out of the cells, they become flaccid.

These potassium pumps are involved in many other aspects of plant movement, too. This includes the opening and closing of stomata (tiny regulated leaf apertures), the rapid movement of mimosa leaves, or the closing of a fly trap.

But sunflowers dance differently

In 2016, scientists discovered that the pin-up example of heliotropism — the sunflower — had a different way of moving.

They found sunflower movement is due to significantly different growth rates on opposite sides of the flowering stem.

A sunflower facing a setting sun — Sunflowers move differently to other heliotropic flowers.
Aaron Burden/Unsplash

On the east-facing side, the cells grow and elongate quickly during the day, which slowly pushes the flower to face west as the daylight hours go by — following the sun. At night the west-side cells grow and elongate more rapidly, which pushes the flower back toward the east over night.

Everything is then set for the whole process to begin again at dawn next day, which is repeated daily until the flower stops growing and movement ceases.

While many people are aware of heliotropism in flowers, heliotropic movement of leaves is less commonly noticed or known. Plants with heliotropic flowers don’t necessarily have heliotropic leaves, and vice versa.

Heliotropism evolves in response to highly specific environmental conditions, and factors affecting flowers can be different from those impacting leaves.

The leaves of Queensland box, *Lophostemon confertus*, which track the sun.
Krzysztof Ziarnek, Kenraiz/Wikimedia Commons, CC BY-SA

For example, flowers are all about pollination and seed production. For leaves, it’s for maximising photosynthesis, avoiding over-heating on a hot day or even reducing water loss in harsh and arid conditions.

Some species, such as the Queensland box, arrange their leaves so they’re somewhat horizontal in the morning, capturing the full value of the available sunlight. But there are also instances where leaves align vertically to the sun in the middle of the day to minimise the risks of heat damage.

Plants are dynamic

It’s easy to think of plants as static organisms. But of course, they are forever changing, responding to their environments and growing. They are dynamic in their own way, and we tend to assume that when they do change, it will be at a very slow and steady pace.

Heliotropism shows us this is not necessarily the case. Plants changing daily can be a little unsettling in that we sense a change but may not be aware of what is causing our unease.

As for me, I still keep a watchful eye on those Queensland boxes!

Gregory Moore, Doctor of Botany, The University of Melbourne

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

Flies like yellow, bees like blue: how flower colours cater to the taste of pollinating insects

Hoverfly (*Eristalis tenax*) feeding on marigold.
Fir0002/Flagstaffotos, CC BY-NC

Jair Garcia, RMIT University; Adrian Dyer, RMIT University, and Mani Shrestha, Bayreuth UniversityWe all know the birds and the bees are important for pollination, and we often notice them in gardens and parks. But what about flies?

Flies are the second most common type of pollinator, so perhaps we should all be taught about the bees, the flies and then the birds. While we know animals may see colour differently, little was known about how fly pollination shapes the types of flowers we can find in nature.

In our new study we address this gap in our knowledge by evaluating how important fly pollinators sense and use colour, and how fly pollinated flowers have evolved colour signals.

Specialed flower visiting flies: a hoverfly (*Eristalis tenax*) (left panel), and a bee-fly (*Poecilanthrax apache*) (right panel)
Michael Becker, Pdeley

The way we see influences what we choose

We know that different humans often have preferences for certain colours, and in a similar way bees prefer blue hues.

Our colleague Lea Hannah has observed that hoverflies (Eristalis tenax) are much better at distinguishing between different shades of yellow than between different blues. Other research has also reported hoverflies have innate responses to yellow colours.

Many flowering plants depend on attracting pollinators to reproduce, so the appearance of their flowers has evolved to cater to the preferences of the pollinators. We wanted to find out what this might mean for how different insects like bees or flies shape flower colours in a complex natural environment where both types of insect are present.

The Australian case study

Australia is a natural laboratory for understanding flower evolution due to its geological isolation. On the mainland Australian continent, flowers have predominately evolved colours to suit animal pollination.

Around Australia there are plant communities with different pollinators. For example, Macquarie Island has no bees, and flies are the only animal pollinator.

We assembled data from different locations, including a native habitat in mainland Australia where both bees and flies forage, to model how different insects influence flower colour signal evolution.

Measuring flower colours

Since we know different animals sense colour in different ways, we recorded the spectrum of different wavelengths of light reflected from the flowers with a spectrometer. We subsequently modelled these spectral signatures of plant flowers considering animal perception, allowing us to objectively quantify how signals have evolved. These analyses included mapping the evolutionary ancestry of the plants.

Generalisation or specialisation?

According to one school of thought, flower evolution is driven by competition between flowering plants. In this scenario, different species might have very different colours from one another, to increase their chances of being reliably identified and pollinated. This is a bit like how exclusive brands seek customers by having readily identifiable branding.

An alternative hypothesis to competition is facilitation. Plants may share preferred colour signals to attract a higher number of specific insects. This explanation is like how some competing businesses can do better by being physically close together to attract many customers.

Our results demonstrate how flower colour signalling has dynamically evolved depending on the availability of insect pollinators, as happens in marketplaces.

In Victoria, flowers have converged to evolve colour signals preferred by their pollinators. The flowers of fly-pollinated orchids are typically yellowish-green, while closely related orchids pollinated by bees have more bluish and purple colours. The flowers appeared to share the preferred colours of their main pollinator, consistent with a facilitation hypothesis.

Typical flowers preferred by bees (*Lobelia rhombifolia*, left panel) and flies (*Pterostylis melagramma*, right panel) encountered in our study sites. Inserts show the spectral profile for each species as measured by a spectrometer.
Mani Shrestha

Our research showed flies can see differences between flowers of different species in response to the pollinator local “market”.

On Macquarie Island, where flies are the only pollinators, flower colours diverge from each other – but still stay within the range of the flies’ preferred colours. This is consistent with a competition strategy, where differences between plant species allow flies to more easily identify the colour of recently visited flowers.

When both fly and bee pollinators are present, flowers pollinated by flies appear to “filter out” bees to reduce the number of ineffective and opportunistic visitors. For example, in the Himalayas specialised plants require flies with long tongues to access floral rewards. This is similar to when a store wants to exclusively attract customers specifically interested in their product range.

Our findings on fly colour vision, along with novel precision agriculture techniques, can help using flies as alternative pollinators of crops. It also allows us to understand that if we want to see a full range of pollinating insects including beautiful hoverflies in our parks and gardens, we need to plant a range of flower types and colours.

Jair Garcia, Research fellow, RMIT University; Adrian Dyer, Associate Professor, RMIT University, and Mani Shrestha, Postdoc & International Fellow, Disturbance Ecology, Bayreuth University

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

How would planting 8 billion trees every year for 20 years affect Earth’s climate?

Planting 8 billion trees a year would replace about half of the 15 billion cut down annually.
Michael Tewelde/AFP via Getty Images

Karen D. Holl, University of California, Santa Cruz

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.

If we planted 8 billion trees a year for 20 years, what would happen on Earth? – Shivam K., age 14, Nawada, Bihar, India

Politicians, business leaders, YouTubers and celebrities are calling for the planting of millions, billions or even trillions of trees to slow climate change.

There are currently almost 8 billion people on Earth. If every single person planted a tree each year for the next 20 years, that would mean roughly 160 billion new trees.

Could massive tree planting actually slow climate change?

Trees and carbon

Carbon dioxide is the main gas that causes global warming. Through photosynthesis, trees and other plants transform carbon dioxide from the atmosphere into carbohydrates, which they use to make stems, leaves and roots.

The amount of carbon a tree can store varies a great deal. It depends on the tree species, where it is growing and how old it is.

Let’s say the average tree takes up 50 pounds of carbon dioxide a year. If a person planted a tree every year for 20 years – and each one survived, which is highly unlikely – those 20 trees would take up about 1,000 pounds, or half a ton, of carbon dioxide per year.

The average person in the United States produces a whopping 15.5 tons of carbon dioxide a year compared with 1.9 tons for an average person in India. This means that if each person in the U.S. planted one tree per year it would offset only about 3% of the carbon dioxide they produce each year, after all 20 trees had matured. But, it would offset 26% for somebody in India.

Planting trees is certainly part of the solution to climate change, but there are more important ones.

Aerial view of patchwork deforestation of rainforest. — Clearing the Amazon rainforest for livestock farms in Brazil in 2017.
Brazil Photos/LightRocket via Getty Images

Protecting the trees we have

There are about 3 trillion trees on Earth, which is only half as many as 12,000 years ago, at the start of human civilization.

People cut down an estimated 15 billion trees each year. A lot of those trees are in tropical forests, but deforestation is happening all over the planet.

Protecting existing forests makes sense. Not only do they absorb carbon dioxide in the trees and the soil, but they provide habitat for animals. Trees can provide firewood and fruit for people. In cities, they can offer shade and recreational spaces.

But trees should not be planted where they didn’t grow before, such as in native grasslands or savannas. These ecosystems provide important habitat for their own animals and plants – and already store carbon if they are left undisturbed.

Doing more

To slow climate change, people need to do much more than plant trees. Humans need to reduce their carbon dioxide and other greenhouse gas emissions quickly by transitioning to renewable energy sources, like solar and wind. People should also reduce the amount they drive and fly – and eat less meat, as meat has a much larger carbon footprint per calorie than grains and vegetables.

It is important that everybody – businesses, politicians, governments, adults and even kids – do what they can to reduce fossil fuel emissions. I know it can seem pretty overwhelming to think about what you as one person can do to help the planet. Fortunately, there are many options.

Volunteer with a local conservation organization, where you can help protect and restore local habitats. Discuss with your family new lifestyle choices, like biking, walking or taking public transit rather than driving.

Two Girl Scouts take a stand against deforestation.

And don’t be afraid to lead an effort to protect trees, locally or globally. Two 11-year-old Girl Scouts, concerned about the destruction of rainforests for palm oil plantations, led an effort to eliminate palm oil in Girl Scout cookies.

Sometimes change is slow, but together people can make it happen.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Karen D. Holl, Professor of Restoration Ecology, University of California, Santa Cruz

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

Western Australia in Full Bloom

Planning to plant an Australian native like wattle? Read this first — you might be spreading a weed

Coastal wattle.
Dr David Chael, Author provided

Singarayer Florentine, Federation University AustraliaAustralian native plants are having a moment in the sun, with more of us seeking out and planting native species than in the past. Our gardens — and our social media feeds — are brimming with beautiful Australian native blooms.

But not all Australian native species belong in all Australian environments. In fact, many have become pests in places far from their original homes.

They can crowd out other native endemic species, affect the local balance of insects and other animals, wreck soils and even increase fire risk.

Here are three Australian native plants that have become invasive species after ending up in places they don’t belong.

Sydney golden wattle (Acacia longifolia subspecies longifolia)

Originally extending from East Gippsland in Victoria up about as far as Brisbane in Queensland, this species is undoubtedly photogenic. It’s also an invasive weed in parts of Victoria, South Australia and Western Australia.

It was spread across the nation by well-meaning gardeners who saw it as a charming ornamental plant. However, its seeds made their way into the wild and took off — it’s what’s known in my field as “a garden escapee”.

Like many weeds, this species can capitalise on a natural disaster; after fire it can send out shoots from its base. Acacias are often one of the first species to sprout following a bushfire. They’re now completely dominant and spreading in many areas.

Sydney golden wattle is an invasive weed in other parts of Victoria, South Australia and Western Australia.
Gill Armstrong, Author provided

Seeds of Sydney golden wattle can last in the soil for many decades, long after the parent plants have died. The heat from a fire cracks the hard seed coat, allowing water to enter and germination to take off.

In the Grampians, in Victoria, Sydney golden wattle is causing terrible soil problems. Many native plants endemic to this area don’t like high levels of soil nitrogen, but Acacia longifolia subsp. longifolia is a nitrogen-fixing plant.

Acacia longifolia subsp. longifolia has quite long, thin seed pods.
Gill Armstrong, Author provided

In other words, it increases the nitrogen in the soil and changes the soil nutrient status and even physical aspects of the soil. It can grow tall and produce a lot of foliage, which reduces the amount of light coming to the ground. That makes it harder for native species lower to the ground to survive.

This is a major challenge, especially in biodiversity-rich places like the Grampians.

Coast wattle (Acacia longifolia subspecies sophorae)

The blooms on Acacia longifolia subspecies sophorae (Coast wattle) look more or less the same as many other wattles, but the leaves are a bit shorter and stubbier.

Originally, Coast wattle occurred along the east coast from western Victoria — up about as far as Brisbane and down south as far as Tasmania (where Sydney golden wattle did not occur naturally).

_Acacia longifolia subsp. sophorae_, also known as 'Coastal Wattle', has shorter, stubby leaves. — Acacia longifolia subsp. sophorae, also known as ‘Coastal Wattle’, has shorter, stubby leaves.
Tatters ✾/Flickr, CC BY

It was originally restricted to sandy sites at the top of beaches but has been deliberately planted as a “sand-binder” in other sites. It’s also naturally spread into heathlands inland of the beaches and is now causing huge problems around our coasts.

Like the earlier example, it dominates local ecosystems and displaces native species endemic to the area (particularly in our species-rich heathlands), which affects local insect habitats. It is also now modifying natural sand dune patterns.

It is increasing fire risk by changing heathland plant profiles from mostly short shrubs of limited bulk to tall, dense shrublands with much higher fuel levels.

Coast teatree (Leptospermum laevigatum)

As with Coast wattle, Coast teatree was formerly restricted to a narrow strip on sandy soils just above the beaches of south-eastern Australia. But it has now spread into nearby heathlands and woodlands. It’s even reached as far as Western Australia.

This teatree plant is now considered an invasive species in parts of Victoria and South Australia.

Although the mature plants are usually killed by fire, the seeds are abundant and very good at surviving; they pop out of their capsules after fires.

Coast teatree produces a lot of seeds.
Dr David Chael, Author provided

They are high-density plants that burn quickly in a fire. They are very quick to take over and push out endemic species.

For example, parts of the Wilson’s Prom National Park in Victoria, which was originally a Banksia woodland, have now been converted almost to a teatree monoculture. It is very sad.

A call to action

Authorities are trying their best to keep these and other native invasive species under control, but in some cases things may never go back to the way they were. Sometimes, the best you can hope for is just to strike a balance between native and invasive species.

When you do landcare restoration work or home gardening, I urge you to look up the plant history and see if the species you’re thinking of planting is listed as one that might cause problems in future.

When you go to purchase from a nursery or plant centre, be cautious. Think twice before you bring something into your garden. Too many species have “jumped the garden fence” and now cost us a great deal in control efforts and in native species loss.

Lots of apps, such as PlantNet, can help you identify plants and see what is native to your area.

Australia has spent billions trying to control invasive species and environmental weeds. Anything you can do to help is a bonus.

Singarayer Florentine, Professor (Restoration Ecologist), Federation University Australia

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

Super Roots

About 500,000 Australian species are undiscovered – and scientists are on a 25-year mission to finish the job

Kevin Thiele, The University of Western Australia and Jane Melville, Museums VictoriaHere are two quiz questions for you. How many species of animals, plants, fungi, fish, insects and other organisms live in Australia? And how many of these have been discovered and named?

To the first, the answer is we don’t really know. But the best guess of taxonomists – the scientists who discover, name, classify and document species – is that Australia’s lands, rivers, coasts and oceans probably house more than 700,000 distinct species.

On the second, taxonomists estimate almost 200,000 species have been scientifically named since Europeans first began exploring, collecting and classifying Australia’s remarkable fauna and flora.

Together, these estimates are disturbing. After more than 300 years of effort, scientists have documented fewer than one-third of Australia’s species. The remaining 70% are unknown, and essentially invisible, to science.

Taxonomists in Australia name an average 1,000 new species each year. At that rate, it will take at least 400 years to complete even a first-pass stocktake of Australia’s biodiversity.

This poor knowledge is a serious threat to Australia’s environment. And a first-of-its kind report released today shows it’s also a huge missed economic opportunity. That’s why today, Australia’s taxonomists are calling on governments, industry and the community to support an important mission: discovering and documenting all Australian species within 25 years.

Australia: a biodiversity hotspot

Biologically, Australia is one of the richest and most diverse nations on Earth – between 7% and 10% of all species on Earth occur here. It also has among the world’s highest rates of species discovery. But our understanding of biodiversity is still very, very incomplete.

Of course, First Nations peoples discovered, named and classified many species within their knowledge systems long before Europeans arrived. But we have no ready way yet to compare their knowledge with Western taxonomy.

Finding new species in Australia is not hard – there are almost certainly unnamed species of insects, spiders, mites and fungi in your backyard. Any time you take a bush holiday you’ll drive past hundreds of undiscovered species. The problem is recognising the species as new and finding the time and resources to deal with them all.

Taxonomists describe and name new species only after very careful due diligence. Every specimen must be compared with all known named species and with close relatives to ensure it is truly a new species. This often involves detailed microscopic studies and gene sequencing.

More fieldwork is often needed to collect specimens and study other species. Specimens in museums and herbaria all over the world sometimes need to be checked. After a great deal of work, new species are described in scientific papers for others to assess and review.

So why do so many species remain undiscovered? One reason is a shortage of taxonomists trained to the level needed. Another is that technologies to substantially speed up the task have only been developed in the past decade or so. And both these, of course, need appropriate levels of funding.

Of course, some groups of organisms are better known than others. In general, noticeable species – mammals, birds, plants, butterflies and the like – are fairly well documented. Most less noticeable groups – many insects, fungi, mites, spiders and marine invertebrates – remain poorly known. But even inconspicuous species are important.

Fungi, for example, are essential for maintaining our natural ecosystems and agriculture. They fertilise soils, control pests, break down litter and recycle nutrients. Without fungi, the world would literally grind to a halt. Yet, more than 90% of Australian fungi are believed to be unknown.

fungi on log — Fungi plays an essential ecosystem role.
Shutterstock

Mind the knowledge gap

So why does all this matter?

First, Australia’s biodiversity is under severe and increasing threat. To manage and conserve our living organisms, we must first discover and name them.

At present, it’s likely many undocumented species are becoming extinct, invisibly, before we know they exist. Or, perhaps worse, they will be discovered and named from dead specimens in our museums long after they have gone extinct in nature.

Second, many undiscovered species are crucial in maintaining a sustainable environment for us all. Others may emerge as pests and threats in future; most species are rarely noticed until something goes wrong. Knowing so little about them is a huge risk.

Third, enormous benefits are to be gained from these invisible species, once they are known and documented. A report released today
by Deloitte Access Economics, commissioned by Taxonomy Australia, estimates a benefit to the national economy of between A$3.7 billion and A$28.9 billion if all remaining Australian species are documented.

Benefits will be greatest in biosecurity, medicine, conservation and agriculture. The report found every $1 invested in discovering all remaining Australian species will bring up to $35 of economic benefits. Such a cost-benefit analysis has never before been conducted in Australia.

The investment would cover, among other things, research infrastructure, an expanded grants program, a national effort to collect specimens of all species and new facilities for gene sequencing.

Two scientists walk through wetlands holding boxes — Discovering new species often involves lots of field work.
Shutterstock

Mission possible

Australian taxonomists – in museums, herbaria, universities, at the CSIRO and in
government departments – have spent the last few years planning an ambitious mission to discover and document all remaining Australian species within a generation.

So, is this ambitious goal achievable, or even imaginable? Fortunately, yes.

It will involve deploying new and emerging technologies, including high-throughput robotic DNA sequencing, artificial intelligence and supercomputing. This will vastly speed up the process from collecting specimens to naming new species, while ensuring rigour and care in the science.

A national meeting of Australian taxonomists, including the young early career researchers needed to carry the mission through, was held last year. The meeting confirmed that with the right technologies and more keen and bright minds trained for the task, the rate of species discovery in Australia could be sped up by the necessary 16-fold – reducing 400 years of effort to 25 years.

With the right people, technologies and investment, we could discover all Australian species. By 2050 Australia could be the world’s first biologically mega-rich nation to have documented all our species, for the direct benefit of this and future generations.

Kevin Thiele, Adjunct Assoc. Professor, The University of Western Australia and Jane Melville, Senior Curator, Terrestrial Vertebrates, Museums Victoria

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

The 50 beautiful Australian plants at greatest risk of extinction — and how to save them

Caley’s grevillea (*Grevillea caleyi*) occurs in Sydney. It needs fire to germinate but burns are hard to carry out near urban areas.
Tony Auld, Author provided

Jennifer Silcock, The University of Queensland; Jaana Dielenberg, Charles Darwin University; Roderick John Fensham, The University of Queensland, and Teghan Collingwood, The University of QueenslandAs far as odds go, things don’t look promising for the slender-nerved acacia (Acacia leptoneura), a spiky plant with classic yellow-ball wattle flowers. With most of its habitat in Western Australia’s wheat belt cleared for agriculture, it was considered extinct for more than 160 years.

Now, just two plants are known in the world, and they’re not even in the same place. This species is among many Australian plants that have come perilously close to extinction.

To help prevent the loss of any native plant species, we’ve assembled a massive evidence base for more than 750 plants listed as critically endangered or endangered. Of these, we’ve identified the 50 at greatest risk of extinction.

The good news is for most of these imperilled plants, we already have the knowledge and techniques needed to conserve them. We’ve devised an action plan that’s relatively easy to implement, but requires long-term funding and commitment.

What’s driving the loss?

There are 1,384 plant species and subspecies listed as threatened at a national level. Twelve Australian plant species are considered probably extinct and a further 21 species possibly extinct, while 206 are officially listed as critically endangered.

Yellow wattle — Two known plants of slender nerved acacia (*Acacia leptoneura*) remain, about 1 kilometre apart. Propagation attempts have been unsuccessful and the genetic diversity is probably very low.
Joel Collins, Author provided

Australian plants were used, managed and celebrated by Australia’s First Nations people for at least 60,000 years, but since European colonisation, they’ve been beset by a range of threats.

Land clearing, the introduction of alien plants, animals, diseases, and interruptions to ecological processes such as fire patterns and flooding have taken a heavy toll on many species. This is particularly the case in the more densely populated eastern and southern parts of the continent.

Close-up of yellow flower — Ironstone pixie mop (*Petrophile latericola*) occurs on a soil type that’s been heavily cleared for agriculture, and is suspected to be susceptible to an introduced root-rot fungus. In 2020 fewer than 200 plants remained, in poor condition.
Andrew Crawford, Author provided

Things aren’t improving. Scientists recently compiled long-term monitoring of more than 100 threatened plant species at 600 sites nationally. And they found populations had declined on average by 72% between 1995 and 2017.

This is a very steep rate of decline, much greater than for threatened mammal or bird populations.

On the brink

Many species listed as threatened aren’t receiving targeted conservation action or even baseline monitoring, so an important first step in preventing extinctions was identifying the species at greatest risk.

To find the top 50, we looked at the evidence: all available published and unpublished information and expert surveys of over 120 botanists and land managers.
They’re targeted by our Action Plan for Australia’s Imperilled Plants.

Action Plan for Australia’s Imperilled Plants.

Thirty of the species in the plan have fewer than 50 mature individual plants remaining.

And 33 are known only from a single location, such as the Grampians pincushion-lily (Borya mirabilis), which occurs on one rocky outcrop in Victoria. This means the entire population could be destroyed by a single event, such as a major bushfire.

A dead-looking gum tree on agricultural land — About 2,000 Morrisby’s gums were growing in the early 1990s, but by 2016 fewer than 50 remained. Climate change and damage from insects and animals threaten those left. Protecting trees with fencing has led to new seedlings.
Magali Wright, Author provided

Fewer than 10 lax leek-orchids (*Prasophyllum laxum*) remain. Declines are ongoing due to drought and wildfire, and the South Australian species only occurs on private property not managed for conservation. Proposed recovery actions include habitat protection and establishing the orchid and its mycorrhizal fungi in conservation reserves.
Shane Graves, Author provided

Fewer than 15 woods well spyridium (*Spyridium fontis-woodii*) shrubs remain on a single roadside in South Australia. Research into threats and germination requirements is urgently needed, plus translocation to conservation reserves.
Daniel Duval/South Australian Seed Conservation Centre, Author provided

So how can we protect them?

Some of the common management actions we’ve proposed include:

preventing further loss of species’ habitat. This is the most important action required at a national scale
regularly monitoring populations to better understand how species respond to threats and management actions
safely trialling appropriate fire management regimes, such as burning in areas where fires have been suppressed
investing in disease research and management, to combat the threat of phytophthora (root-rot fungus) and myrtle rust, which damages leaves
propagating and moving species to establish plants at new sites, to boost the size of wild populations, or to increase genetic diversity
protecting plants from grazing and browsing animals, such as feral goats and rabbits, and sometimes from native animals such as kangaroos.

Once common, the dwarf spider-orchid (*Caladenia pumila*) wasn’t seen for over 80 years until two individual plants were found. Despite intensive management, no natural recruitment has occurred. Propagation attempts have successfully produced 100 seedlings and 11 mature plants from seed. This photo shows botanist Marc Freestone hand-pollinating dwarf spider-orchids.
Marc Freestone, Author provided

Only 21 mature plants of Gillingarra grevillea (*Grevillea sp. Gillingarra*) remain on a disturbed, weedy rail reserve in southwestern WA. Half the population was destroyed in 2011 due to railway maintenance and flooding. Habitat protection and restoration, and translocations to conservation reserves are needed to ensure its survival.
Andrew Crawford, Author provided

Another common issue is lack of recruitment, meaning there’s no young plants coming up to replace the old ones when they die. Sometimes this is because the processes that triggered these plants to flower, release seed or germinate are no longer occurring. This can include things like fire of a particular intensity or the right season.

Unfortunately, for some plants we don’t yet know what triggers are required, and further research is essential to establish this.

Now we need the political will

Our plan is for anyone involved in threatened flora management, including federal, state, territory and local government groups, First Nations, environment and community conservation groups, and anyone with one of these plants on their land.

The Border Ranges lined fern (*Antrophyum austroqueenslandicum*) and its habitat are exceedingly rare. It’s threatened by drought and climate change, and fewer than 50 plants remain in NSW. If the threat of illegal collection can be controlled, the species would benefit from re-introduction to Queensland’s Lamington National Park.
Lui Weber, Author provided

Plants make Australian landscapes unique — over 90% of our plant species are found nowhere else in the world. They’re also the backbone of our ecosystems, creating the rich and varied habitats for our iconic fauna to live in. Plants underpin and enrich our lives every day.

Now we have an effective plan to conserve the Australian plants at the greatest risk of extinction. What’s needed is the political will and resourcing to act in time.

Jennifer Silcock, Post-doctoral research fellow, The University of Queensland; Jaana Dielenberg, University Fellow, Charles Darwin University; Roderick John Fensham, Associate Professor of Biological Sciences, The University of Queensland, and Teghan Collingwood, Research Technician, The University of Queensland

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

Small breaks in habitat can have big impacts

Disastrous clearing laws

The code should be amended

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What happens when fires become more frequent?

What happens when fire seasons get longer?

When drought and heatwaves get more severe

When threats pile up

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The mechanics of tracking the sun

But sunflowers dance differently

Plants are dynamic

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The way we see influences what we choose

The Australian case study

Measuring flower colours

Generalisation or specialisation?

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Trees and carbon

Protecting the trees we have

Doing more

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Sydney golden wattle (Acacia longifolia subspecies longifolia)

Coast wattle (Acacia longifolia subspecies sophorae)

Coast teatree (Leptospermum laevigatum)

A call to action

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Australia: a biodiversity hotspot

Mind the knowledge gap

Mission possible

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What’s driving the loss?

On the brink

So how can we protect them?

Now we need the political will

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