Entire hillsides of trees turned brown this summer. Is it the start of ecosystem collapse?

Rachael Nolan, CC BY-NC

Rachael Helene Nolan, Western Sydney University; Belinda Medlyn, Western Sydney University; Brendan Choat, Western Sydney University, and Rhiannon Smith, University of New England

The drought in eastern Australia was a significant driver of this season’s unprecedented bushfires. But it also caused another, less well known environmental calamity this summer: entire hillsides of trees turned from green to brown.

We’ve observed extensive canopy dieback from southeast Queensland down to Canberra. Reports of more dead and dying trees from other regions across Australia are flowing in through the citizen science project, the Dead Tree Detective.

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Read more:
Drought and climate change were the kindling, and now the east coast is ablaze

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A few dead trees are not an unusual sight during a drought. But in some places, it is the first time in living memory so much canopy has died off.

Ecologists are now pondering the implications. There are warnings that some Australian tree species could disappear from large parts of their ranges as the climate changes. Could we be witnessing the start of ecosystem collapse?

Extensive canopy dieback in Kains Flat, NSW, January 2020.
Matt Herbert

Why are canopies dying now?

Much of eastern Australia has been in drought since the start of 2017. While this drought is not yet as long as the Millennium Drought, it appears to be more intense. Many areas have received the lowest rainfall on record, including long periods of time with no rainfall. This has been coupled with above-average temperatures and extreme heatwaves.

The higher the temperature, the greater the moisture loss from leaves. This is usually good for a tree because it cools the canopy. But if there is not enough water in the soil, the increased water loss can push trees over a threshold, causing extensive leaf “scorching”, or browning. The extensive canopy dieback we have observed this summer suggests that the soil had finally become too dry for many trees.

Widespread rainfall deciciencies and higher temperatures across many parts of Australia.
Bureau of Meteorology

Are the trees dead?

Brown or bare trees are not necessarily dead. Many eucalypts can lose all their leaves but resprout after rain.

Many parts of eastern Australia are now flushed with green after rain. In these areas, it will be important to assess the extent of tree recovery. If trees are not showing signs of recovery after significant rainfall, they’re unlikely to survive. In some cases carbohydrate reserves – which trees need to resprout new leaves – may be too depleted for trees to recover.

Snowgums in the New England area resprouting in March 2020, following heavy rain. The trees lost most of their canopy during drought in 2019.
Trevor Stace, University of New England

The drought may also hinder post-fire recovery. Most eucalypt forests eventually recover from bushfires by resprouting new leaves. Some forests also recover when fire triggers seedlings to germinate.

But it’s likely that some forests now recovering from fire were already struggling with canopy dieback. So these two disturbances will test how resilient our forests are to back-to-back drought and bushfire.

Trees recovering from drought and/or fire may also enter the “dieback spiral”. The new flush of leaves following rain can make a particularly tasty meal for insects. Trees will then attempt to grow more foliage in response, but their ability to keep producing new leaves gradually declines as they deplete their carbohydrate reserves, and they can die.

Dieback spiral has led to extensive tree loss in the past, including in the New England area of NSW.

Should we be worried?

The capacity of eucalypts to resprout makes them naturally resilient to extended drought. There are some records of canopy dieback from severe droughts in the past, such as the Federation Drought. We assume (although we don’t know for sure) the forests recovered after these events. So they may bounce back after the current drought.

However, it’s hard not to be concerned. Climate change will bring increased drought, heatwaves and fires that could, over time, see extensive losses of trees across the landscape – as happened on the Monaro High Plain after the Millennium Drought.

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Read more:
Are more Aussie trees dying of drought? Scientists need your help spotting dead trees

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Australian research in 2016 warned that due to climate change, the habitat of 90% of eucalypt species could decline and 16 species were expected to lose their home environments within 60 years.

Such a change would have huge consequences for how ecosystems function – reducing the capacity for ecosystem services such as carbon storage, altering catchment water resources and reducing habitat for native animals.

Some trees resprouted new leaves after losing their canopy. But in some cases these leaves are now dying, like on these scribbly gums in the NSW Pilliga in August 2019.
Rachael Nolan

Where to from here?

Records of dead and dying trees on the Dead Tree Detective map.
Dead Tree Detective

Landholders can help bush on their property recover after drought, by protecting germinating seedlings from livestock and collecting local seed for later revegetation. Trees that appear dead should not be cut down as they may recover, and even if dead can provide valuable animal habitat.

Most importantly, however, we need to monitor trees carefully to see where they’ve died, and where they are recovering. A citizen science project, the Dead Tree Detective, is helping map the extent of tree die-off across Australia.

People send in photos of dead and dying trees – to date, over 267 records have been uploaded. These records can be used to target where to monitor forests during drought, including on-ground assessments of tree health and quantifying the physiological responses of trees to drought stress.

There is no ongoing forest health monitoring program in Australia, so this dataset is invaluable in helping us determine exactly how vulnerable Australia’s forests are to the double whammy of severe drought and bushfires.

Rachael Helene Nolan, Postdoctoral research fellow, Western Sydney University; Belinda Medlyn, Professor, Western Sydney University; Brendan Choat, Associate Professor, Western Sydney University, and Rhiannon Smith, Research Fellow, University of New England

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

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Yes, the Australian bush is recovering from bushfires – but it may never be the same

Grant Williamson, University of Tasmania; Gabi Mocatta, University of Tasmania; Rebecca Harris, University of Tasmania, and Tomas Remenyi, University of Tasmania

As bushfires in New South Wales are finally contained, attention is turning to nature’s recovery. Green shoots are sprouting and animals are returning. But we must accept that in some cases, the bush may never return to its former state.

We’ve all read the devastating figures of destruction this fire season. More than 11 million hectares of land burned across the country over a period of about six months. There is some evidence more than one billion animals perished.

We can take some heart in the regenerative power of the Australian bush.
However, when we read of “recovery” in the media, we feel we must clarify what that might actually look like.

While Australia’s environment has evolved to adapt to fire, our research shows we can no longer assume it will recover completely.

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Read more:
Yes, native plants can flourish after bushfire. But there’s only so much hardship they can take

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A fiery future

We are scientists and social science researchers who work in transdisciplinary climate change projects, liaising with park rangers, farmers, policymakers, emergency services and local government.

Our work involves scoping future challenges in land management and developing a range of plausible future climate scenarios for south-east Australia.

Our experience told us something like this catastrophic climatic event was possible, but as researchers we weren’t prepared to see such an inferno this summer.

Although fires are natural in Australia, they’re now occurring at an unprecedented frequency and intensity in areas that, historically, did not burn. This new regime does not allow the effective recovery of natural systems to their pre-fire state.

Alpine ash to ashes

Fires in alpine ash forests (Eucalyptus delegatensis) are a good example of this.

Along with some eucalyptus trees, Australian flowering grass trees (Xanthorrhoea) are pyrophytic plants – which means they are adapted to survive in fire-prone habitats.
Natalie Maguire / Flickr, CC BY-SA

Unlike many eucalypt species which can re-sprout after fire, this species’ only means of recovery is through germination via a seed bank in the canopy, and rapid germination and growth of seedlings after fire.

Multiple fires in quick succession kill seedlings before they reach maturity, disrupting the tree’s reproductive cycle and leading to local extinction of the species in the landscape.

Alpine ash forests have endured repeated fires in recent years. In 2013, a blaze in Victoria burnt more than 31,000 hectares of the Alpine National Park.

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Read more:
Ash to ashes – what could the 2013 fires mean for the future of our forests?

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Vast areas have been burnt again in this season’s fires in the same places. Research reveals climate change is increasing the frequency and intensity of fires in the Australian Alps.

This ecosystem will not recover. It will instead transition into a new, different ecosystem, and many species which evolved to live in the original habitat, such as the alpine ash, will no longer be supported. They will be replaced by other vegetation types, such as other eucalyptus woodland, shrubland or grassland.

No more refuge

To further illustrate this point, take the Tasmanian pencil pine Athrotaxis cupressoides.

This slow-growing conifer native to Tasmania can live for up to 1,000 years. They are found in Tasmania’s highlands and sub-alpine regions – historically a Tolkien-esque landscape of moss and emerald green cushion plants, studded with thousands of tiny mountain lakes, called tarns.

But large fires across Tasmania’s pencil pine habitat in recent years, including those in 2016, reduced hundreds of isolated pencil pine communities to blackened skeletons. The stands of trees that remain are struggling to survive in a drying and warming climate.

Pencil pines, widely found in Tasmania, are not fire-adapted and are killed by bushfires.
David Bowman

All this is occurring in areas that historically did not experience fire, which allowed a suite of ancient, fire-sensitive species to persist.

As climate change worsens, the pencil pine will be restricted to even smaller areas. Higher temperatures and increased fuel loads increase the likelihood of destruction by fire. Areas where pencil pines have historically been protected will diminish in number and size.

Irreplaceable loss

In these cases and many others, animal species relying on these trees and their ecosystems are profoundly affected.

Well before the latest fires, Australia had an abysmal record on vertebrate extinctions. This summer’s fires have brought some animal species, including the Kangaroo Island dunnart, closer to extinction.

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Read more:
Australia’s bushfires could drive more than 700 animal species to extinction. Check the numbers for yourself

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Future fire seasons will not be normal events, or even some kind of stable “new normal”, to which humans and nature will readily adapt. We’re seeing a trajectory of change in which our climate will shift faster than most living things can tolerate.

The Australian environment evolved with fire and in past conditions, could recover from fire. However climate change has altered the rules irrevocably.

We can no longer rest assured that nature will bounce back, and that knowledge should be a wake-up call for the world.

Grant Williamson, Research Fellow in Environmental Science, University of Tasmania; Gabi Mocatta, Research Fellow in Climate Change Communication, University of Tasmania; Rebecca Harris, Climate Research Fellow, University of Tasmania, and Tomas Remenyi, Climate Research Fellow, Climate Futures Programme, University of Tasmania

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

The small patch of bush over your back fence might be key to a species’ survival

A kangaroo finds refuge in a small patch of vegetation surrounded by a new housing estate.
Georgia Garrard, Author provided

Brendan Wintle, University of Melbourne and Sarah Bekessy, RMIT University

It may not look like a pristine expanse of Amazon rainforest or an African savannah, but the patch of bush at the end of the street could be one of the only places on the planet that harbour a particular species of endangered animal or plant.

Our newly published global study of the conservation value of landscapes in 27 countries across four continents has found these small patches of habitat are critical to the long-term survival of many rare and endangered species.

In Australia, our cities are home to, on average, three times as many threatened species per unit area as rural environments. This means urbanisation is one of the most destructive processes for biodiversity.

It tends to be the smaller patches of vegetation that go first, making way for a housing development, a freeway extension, or power lines. Despite government commitments to enhance the vegetation cover of urban areas and halt species extinctions, the loss of vegetation in Australian cities continues.

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Read more:
We’re investing heavily in urban greening, so how are our cities doing?

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This story plays out all over the world day after day. Of course, it’s not just an urban story. Patches of rural vegetation are continually making way for, say, a new pivot irrigation system or a new mine to provide local jobs.

Remnant salmon gum woodland surrounded by cropland near Bencubbin in Western Australia’s northeast wheatbelt.
Mike Griffiths, Author provided

Mostly, policymakers and scientists do not consider these losses to be, on their own, a fatal blow to the biodiversity of a region or country. Small, often isolated patches of vegetation are considered expendable, tradeable, of limited ecological value due to their small size and relatively large amount of “edgy” habitat. Wrong.

Research forces a rethink

Our study analysed the relationship between conservation value of vegetation patches and their size and isolation in landscapes across Europe, Australia, North America and Africa. The findings prompt a rethink of long-held views about the relative importance of small, isolated habitat patches for biodiversity conservation. We show that these patches often have unique ecological and environmental characteristics.

The critically endangered Western Ringtail Possum lives mainly in small habitat patches in or around urban areas near Perth and is under intense pressure from housing development, foxes, cats and dogs.
Yokochi K., Bencini R./Wikimedia Commons, CC BY

That’s because they are the last patches left over from extensive clearing of flat, fertile land for agriculture or urban growth close to rivers and bays. They often contain habitats for rare or endangered species that have disappeared from the rest of the landscape. This makes these small, isolated patches of habitat disproportionately important for the survival of many species.

Our study calls for a rethink of urban planning and vegetation management regulations and policies that allow small patches of vegetation to be destroyed with lower (and often zero) scrutiny. We argue that the environment is suffering a death by a thousand cuts. The existence of large conservation reserves doesn’t compensate for the small patches of habitat being destroyed or degraded because those reserves tend to contain different species to the ones being lost.

The combined impact of the loss of many small patches is massive. It’s a significant contributor to our current extinction crisis.

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Read more:
Let’s get this straight, habitat loss is the number-one threat to Australia’s species

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Why are small patches seen as dispensable?

A key variable used in decisions on vegetation-clearing applications is the size of patch being destroyed. Authorities that regulate vegetation management and approve applications are more permissive of destruction of small patches of vegetation.

This is partly due to a large body of ecological theory known as island biogeography theory and subordinate theories from metapopulation ecology and landscape ecology. These theories suggest that species richness and individual species’ population sizes depend on the degree of isolation of the patch, its size and the quality of the habitat it contains.

While it is crucial that we conserve large, intact landscapes and wilderness, the problem with conserving only large and well-connected patches of high-quality vegetation is that not all species will be conserved. This is because some species exist only in small, isolated and partially degraded habitats, such as those characteristic of urban bushlands or remnant bush in agricultural areas.

A remnant wetland is still valuable habitat for species like the Pacific Heron.
Wayne Butterworth/Wikimedia Commons, CC BY

For this reason, we highlight the importance of protecting and restoring habitats in these small isolated patches. And these areas do tend to be more vulnerable to invasion by weeds or feral animals. If the impacts of invasive species are not managed, they will eventually lead to the destruction of the habitat values and the loss of the species those habitats support.

Small and isolated patches of vegetation on the urban fringe are under enormous pressure from human use, pets, escaped seed of Agapanthus and the many other invasive species we plant in our gardens. These plants spread into local bushland, where they outcompete the native plants.

Communities can make a difference

As well as these perils, being on the urban fringe also brings opportunity. If a remnant patch of vegetation at the end of the street is seen to be of national environmental importance, that presents a great opportunity to channel the energies of community groups into conserving and restoring these patches.

A patch that is actively cared for by the community will provide better habitat for species. It’s also less likely to fall foul of development aspirations or infrastructure projects. The vicious cycle of degradation and neglect of small patches of habitat can be converted into a virtuous cycle when their value is communicated and local communities get behind preserving and managing them.

Volunteer community groups can play a vital role in preserving and enhancing small habitat patches.
Robin Clarey, Friends of Edithvale Seaford Wetlands, Author provided

Urban planners and developers can get on board too. Rather than policies that enable the loss of vegetation in urban areas, we should be looking at restoring habitats in places that have lost or are losing them. This is key to designing healthy, liveable cities as well as protecting threatened species.

Biodiversity-sensitive urban design makes more of local vegetation by complementing the natural remnant patches with similar habitat features in the built environment, while delivering health and well-being benefits to residents. Urban development should be seen as an opportunity to enhance biodiversity through restoration, instead of an inevitable driver of species loss.

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Read more:
Here’s how to design cities where people and nature can both flourish

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Brendan Wintle, Professor Conservation Ecology, University of Melbourne and Sarah Bekessy, Professor, RMIT University

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

Dealing With Ticks

The link below is to an article that looks at 5 ways to deal with ticks – which also mentions those great pests of the Aussie bush, the drop bears.

For more visit:
http://lotsafreshair.com/2017/01/28/5-tips-for-dealing-with-ticks/

Why a walk in the woods really does help your body and your soul

Jeffrey Craig, Murdoch Childrens Research Institute and Susan L. Prescott, University of Western Australia

Have you ever wondered why you feel healthier and happier when you stroll through the trees or frolic by the sea? Is it just that you’re spending time away from work, de-stressing and taking in the view? Or is there more to it?

For more than 20 years, scientists have been trying to determine the mechanisms by which exposure to biodiversity improves health. Japanese scientists pioneered the search when they travelled to the island of Yakushima, famous for its biodiversity.

The Japanese already had a name for the experience of well-being in nature: shinrin-yoku or “forest bathing”.

Bathe yourself in the forests of Japan’s Yakushima island.
Alan Logan, Author provided

We do know that a diverse ecosystem supports a varied and beneficial microbial community living around and inside us.

We also know that exposure to green space, even within urban environments, increases our physical and mental well-being. But what are the mechanisms?

The forest air

The Japanese researchers suggested that we are taking in beneficial substances when we breathe forest air.

Research has identified three major inhaled factors that can make us feel healthier. These factors are beneficial bacteria, plant-derived essential oils and negatively-charged ions.

From birth to the grave, beneficial bacteria surround us; they live in the environment and, importantly, in the air we breathe. We also share almost our entire body with them. The more interaction we have with them, the happier and healthier we are.

This is in part due to our gut-dwelling bacteria, which break down the food we cannot digest and produce substances that benefit us both physically and mentally.

Plants and the bacteria living on them can produce essential oils to fight off harmful microorganisms. These are referred to collectively as phytoncides, literally, “plant-derived exterminators”.

Research on the health benefits of plant essential oils is in its infancy. But one recent study found that a phytoncide from Korean pine trees improved the health and bacterial make-up of pigs.

Notwithstanding some of the pseudoscience that gets wrapped around negative ion generating machines, there is evidence that negative air ions may influence mental outlook in beneficial ways. There are relatively higher levels of negative air ions in forested areas and close to bodies of water. This may factor into the benefits of walking in a forest or near the ocean.

But as the German writer Goethe once said:

Nature has neither kernel nor shell; she is everything at once.

Bacteria, essential oils and negative ions interact and influence each other. For example, negative ions and phytoncides may dictate the microbial make-up within a natural environment. There is evidence that this could also be taking place in the human gut.

More to be done

Nature-relatedness, or biophilia in which an individual feels connected to nature, has been linked with better health.

But we have a long way to go before we can more fully understand the mechanisms by which an innate love of nature can benefit our health. An important part of this discussion – an overlooked one in our opinion – is further understanding of an individual’s connection to nature.

Psychologists have convincingly demonstrated connections between nature relatedness and mental well-being. But how does a greater personal affinity to nature interact with dietary habits, personal microbiome, physical activity levels and many other lifestyle variables that might be intertwined with having such an affinity?

In the meantime, while scientists turn over stones and search for important mechanistic clues – including those related to biodiversity – there are many simple ways to capitalise on our biophilia.

Live in a city? The take time to walk in the city’s parks and gardens such as Melbourne’s Botanical Gardens.
Flickr/Stephen Barber, CC BY-NC-ND

Why not run in the park or by a river instead of on a treadmill, or take a walk through a park on the way to work or at lunchtime?

Critically, there is increasing evidence that we can help shape our children’s mental and physical health by exposing them to more green environments as they work, rest and play. The US-based Children and Nature Network is a great resource of research news and activities bringing children and nature together.

In the World Health Organization report Connecting Global Priorities – Biodiversity and Human Health, released in December last year, it was concluded that:

Considering ‘microbial diversity’ as an ecosystem service provider may contribute to bridging the chasm between ecology and medicine/immunology [… ] the relationships our individual bodies have with our microbiomes are a microcosm for the vital relationships our species shares with countless other organisms with which we share the planet.

It is easy to see that discussions of natural environments and human health are no mere matter of intellectual fancy.

In a paper published last month in Journal of Physiological Anthropology, we’ve called for more research into the links between biodiversity and human physical and mental well-being, particular in relation to childhood, that most formative of times.

Wouldn’t it be good if by nurturing our environment we were also nurturing our children’s future health?

Jeffrey Craig, Principal Research Fellow, Murdoch Childrens Research Institute and Susan L. Prescott, Professor of Paediatrics, University of Western Australia

This article was originally published on The Conversation. Read the original article.

How to Remove a Tick

The link below is to an infographic on how to remove a tick – very useful for walking in the Australian bush.

For more visit:
http://www.artofmanliness.com/2014/06/11/how-to-remove-a-tick/

Hunter Region Botanic Gardens

Kevin's Daily Photo, Video, Quote or Link

 

ABOVE: The Southern Wetlands Boardwalk – Hunter Region Botanic Gardens

Late last week I decided I should do something with the final day of my annual leave that I had taken this time round, so I thought I’d pop into the Hunter Region Botanic Gardens near Raymond Terrace in New South Wales, Australia. I had been here before, but that was a long time ago. I wasn’t impressed on that first visit, so after more then a decade had it improved? Well that was the question I was keen to answer.

ABOVE: The Rotunda  BELOW: Succulents Section

There was a $4.00 ‘escape’ fee, which would allow a token to be purchased and then the boom gate would rise once it was placed into the proper slot at the exit. So no entrance fee, just an exit fee. I was willing to pay this for a quick look and…

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Blackbutt Reserve

Kevin's Daily Photo, Video, Quote or Link

Since I was unable to visit Gap Creek Falls the other day, I decided I might pop in to have a look at the new animal enclosures at Blackbutt Reserve near Newcastle. I will say straight off the bat that I do have something of a prejudice against Blackbutt Reserve, as I see the place as nothing like a natural bush setting, it being far too ‘corrupted’ by human activity, weeds and the like. Having said that it is a good place for a family or group outing/event. It certainly has its place, but it is not a true nature reserve (in my opinion).

ABOVE: Visitor Centre

I do think that some well designed animal and bird enclosures at Blackbutt could lift the value of the reserve dramatically and make it a really great place for families, especially young families. There are opportunities for educational visits for kids, possible environmental…

View original post 182 more words

Bulahdelah

Kevin's Daily Photo, Video, Quote or Link

So I was right about my day when I spoke of it yesterday. Not a lot going on today, so today’s post will be more about yesterday. I hope that makes perfect sense to everyone – it sounded even worse with the original way I was going to write it (I was trying to be clever, so went for simplicity in the end).

The Punt at Bombah Point On the Punt

To get to Bulahdelah from Hole in the Wall, you need to go via Bombah Point and the ferry service there. I guess you could also call it a punt. Many people still call it that. Anyhow, as the pictures show, it doesn’t cover a great distance. How much is the charge for this journey – at the moment it’s $5.00 AU. Seems a little excessive for something that’s over in less than 5 minutes. Still, there is a…

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Article: How to Buy the Right Bushwalking Boot

Bushwalkers/hikers/trekkers (call it what you will) know that the right boot for an individual walker is absolutely essential out in the wild (or as we might call it Australia, out in the bush or out in the sticks). Many a bushwalk has been ruined or seriously curtailed by having the wrong boot. For me, when I’m doing some serious walking and covering large swathes of territory, blisters become a major problem.

The link below is to an article that provides some tips on what to look for when buying a bushwalking boot.

For more visit:
http://www.australiangeographic.com.au/outdoor/guide-to-buying-the-perfect-hiking-boot.htm.