The showy everlasting is endangered, but a primary school is helping out



The showy everlasting is being grown at Woodlupine Primary School.
Andrew Crawford, Author provided

Leonie Monks, Murdoch University; Alanna Chant, and Andrew Crawford

Western Australia boasts seemingly endless fields of pink, white and yellow everlasting daisies. But while there might seem to be an infinite number, one species in particular is actually endangered. The showy everlasting (or Schoenia filifolia subsp. subulifolia) once grew in the Mid West of WA. Now it is found in just a few spots around the tiny inland town of Mingenew.

But a WA primary school is helping my colleagues and me save the beautiful showy everlasting. With new seed banks, a genetic project and a whole lot of digging, we’re hopeful we can keep this gorgeous native daisy around for the next generation.




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A grower and a shower

The first European to collect the showy everlasting was eminent botanist James Drummond, most likely in the mid-1800s. Initially the species was placed in the Helichrysum family (a group of plants also known as everlastings), but in 1992 botanist Paul Wilson formally described the species based on a specimen collected from Geraldton.

The genus name Schoenia is in honour of the 19th-century eye specialist and botanical illustrator Johannes Schoen, and the species name filifolia refers to its long, slender leaves.

Showy everlastings retain their colour long after they’re picked and dried.
Andrew Crawford, Author provided

Everlastings get their name from the fact that that the flowers hold their colour long after they have been picked and dried. The species is known as the showy everlasting because its large, brightly coloured flowers put on a spectacular show when in bloom.

The showy everlasting is an annual plant, growing around 30cm high, with long narrow leaves. Its bright yellow flowers bloom from August to October. The showy everlasting has two closely related sister species: the more common Schoenia filifolia subsp. filifolia, found throughout the WA Wheatbelt, and Schoenia filifolia subsp. arenicola, which grows around Carnarvon but hasn’t been collected for decades. The main differences between the showy everlasting and its sister species are the much larger flowers and the shape of the base of the flower, which is hemispherical rather than vase-shaped.




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Collections of the showy everlasting housed in the Western Australian Herbarium indicate the species was once more widespread. It’s likely land clearing for farms and infrastructure led to the disappearance of the species from much of its known range.

It was listed as endangered in 2003. At that time the species was found in just three locations. At each of these sites, threats such as chemical drift from nearby agricultural land, grazing by animals, competition from weeds, and increasing soil salinity were all jeopardising the survival of the species.

Unfortunately, by the late 2000s two of these three populations had succumbed to these threats and were lost. However, continued search efforts since then have uncovered two new populations. The showy everlasting is hanging on, but a concerted conservation effort is needed to ensure its survival in the wild.

New populations needed

To ensure the long-term survival of the showy everlasting, we need to establish new populations – a process called translocation.

As an insurance policy, in 2007 seeds were collected and frozen in the Threatened Flora Seed Vault at the Western Australia Seed Centre. In 2015 my colleagues and I used some of these seeds in small-scale translocation trials, successfully getting new plants to grow, flower and seed in three small populations.

Despite this success, we knew the populations would need to be much, much larger and we would need many more populations to ensure persistence of the species. And for that we needed more information about the showy everlasting’s biology, and larger amounts of seed.

Currently a genetic study is underway to look at the difference between the showy everlasting in different locations and its sister species. As part of my PhD study with Murdoch University, I am running a glasshouse experiment to see whether different populations of the showy everlasting can cross and produce viable seed, and whether there are benefits or risks to such crosses.

The initial translocation trials have proved we can successfully establish new populations, but we’re currently limited by the amount of available seed. This is because our trials showed the most efficient way to establish the showy everlasting is by planting seeds directly into the ground. However, this process uses a lot of seeds – more than we have stored in the Seed Vault. Rather than denude the wild populations, we needed a new source.

Fortunately, at this time Andrew Crawford, manager of the Threatened Flora Seed Vault at the Western Australian Seed Centre, was approached by the principal of the Woodlupine Primary School, Trevor Phoebe. He was looking for a meaningful way to involve his students with plant conservation. This led to the establishment of a seed production area at the school which aims to grow and harvest seed of the showy everlasting. The students at the school are involved with planting, monitoring and taking care of the plants, and will help collect the seed when they ripen.




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It is still early days for this project, however early signs are promising. Seedlings have established well and have begun flowering. Seed collection is planned for later in the year.

The seed harvested will be used in the future to boost plant numbers in the existing populations, and to establish new sites, hopefully securing this beautiful species in the wild so that everyone can enjoy the showy everlasting for decades to come.


Do you love native plants? Sign up to The Conversation’s Beating Around the Bush Facebook group.The Conversation

Leonie Monks, Research scientist, Murdoch University; Alanna Chant, Invited User, and Andrew Crawford, Research scientist

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

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Trees can add $50,000 value to a Sydney house, so you might want to put down that chainsaw



Allowing residents to remove trees within three metres of buildings or ‘ancillary structures’ could dramatically alter the green infrastructure of dense inner Sydney suburbs like Rozelle.
Tom Casey/Shutterstock

Sara Wilkinson, University of Technology Sydney; Agnieszka Zalejska-Jonsson, KTH Royal Institute of Technology, and Sumita Ghosh, University of Technology Sydney

Sydney’s Inner West Council has a new policy that it is reported means “residents will no longer need to seek council approval to prune or remove trees within three metres of an existing home or structure”. Hold on, don’t reach for that chainsaw yet, because research shows good green infrastructure – trees, green roofs and walls – can add value to your home.

Green infrastructure offers significant, economic, social and environmental benefits. Urban greening is particularly important in dense urban areas like Sydney’s Inner West. Among its benefits, green infrastructure:

Some of these benefits accrue to owners/occupiers, whereas others provide wider societal benefits.




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A 2017 study focusing on three Sydney suburbs found a 10% increase in street tree canopy could increase property values by A$50,000 on average. And the shading effect of trees can reduce energy bills by up to A$800 a year in Sydney. So retaining your green infrastructure – your trees, that is – can deliver direct financial gains.

On a larger scale, a collaborative project with Horticulture Innovation Australia Limited compared carbon and economic benefits from urban trees considering different landuses along sections of two roads in Sydney. Higher benefits were recorded for the Pacific Highway, with 106 trees per hectare and 58.6% residential land use, compared to Parramatta Road, with 70 trees per hectare and 15.8% residential.

For the Pacific Highway section, total carbon storage and the structural value of trees (the cost of replacing a tree with a similar tree) were estimated at A$1.64 million and A$640 million respectively. Trees were also valuable for carbon sequestration and removing air pollution.

Tree species, age, health and density, as well as land use, are key indicators for financial and wider ecosystem benefits. Specifically, urban trees in private yards in residential areas are vital in providing individual landowner and collective government/non-government benefits.

Take away the trees close to these houses in Marrickville, in Sydney’s Inner West, and how much would be left?
Graeme Bartlett/Wikipedia, CC BY-SA

Challenges of growth

As populations grow, cities increase density, with less green infrastructure. The loss of greenery affects the natural environment and both human and non-human well-being.




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Tree canopy cover across Greater Sydney plummets closer to the city centre.
© State of New South Wales through the Greater Sydney Commission. Data: SPOT5 Woody Extent and Foliage Projective Cover (FPH) 5-10m, 2011, NSW Office of Environment and Heritage

Trees and other green infrastructure reduce some impacts of urban density. However, policies, government incentives and national priorities can produce progress in urban greening or lead to setbacks. In the case of the Inner West Council, for instance, the inability to fund monitoring of changes in tree cover could lead to reductions at the very time when we need more canopy cover.

Key concerns include installation and maintenance costs of green infrastructure (trees, green roofs and walls) in property development, and tree root damage. Knowledge and skills are needed to maintain green infrastructure. As a result, developers often consider other options more feasible.

In the short and long term, multiple performance benefits and economic and environmental values are needed to establish the viability of green infrastructure.




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Learning from Stockholm

Stockholm shares many issues found in Australian cities. Stockholm houses over 20% of Sweden’s inhabitants, is increasing in density and redeveloping land to house a growing population. Aiming to be fossil-free by 2050, Stockholm acknowledges the built environment’s role in limiting climate change and its impacts.

In a research project we intend to use virtual reality (VR) and electroencephalogram (EEG) technology to assess perceptions of green infrastructure and reactions to it in various spaces.

Our project combines VR with EEG hardware, which measures human reactions to stimuli, to learn how people perceive and value green infrastructure in residential development.

Identifying all the value of green infrastructure

The many benefits of green infrastructure are both tangible and non-tangible. Economic benefits include:

  • those that directly benefit owners, occupants or investors – stormwater, increased property values and energy savings
  • other financial impacts – greenhouse gas savings, market-based savings and community benefits.



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The various approaches to evaluating net value present a challenge in quantifying the value of green infrastructure. The most common – cost-benefit analysis, triple bottom line, life cycle assessment and life cycle costing – are all inadequate for evaluating trade-offs between economic and environmental performance. Conventional cost-benefit analysis is insufficient for investment analysis, as it doesn’t include environmental costs and benefits.

This is salient for green infrastructure, as owners/investors incur substantial direct costs, whereas various shareholders share the value. Perhaps, in recognition of the shared value, a range of subsidies could be adopted to compensate investors. Discounted rates anyone?

Recent efforts to evaluate the business case for green infrastructure include attempts to identify and quantify the creation of economic, environment and community/social value. However, an approach that includes a more comprehensive set of value drivers is needed to do this. This is the gap we aim to fill.

The results of experiments using VR and EEG technology and semi-structured interviews will provide a comprehensive understanding of green infrastructure. This will be correlated with capital and rental values to determine various degrees of willingness to pay.

With this knowledge, property developers in Sweden and Australia will be able to make a more informed and holistic business case for increasing green infrastructure for more liveable, healthy cities.

Maybe we can then persuade more people, including those in the Inner West, to hang onto their trees and leave the chainsaws in the garage.The Conversation

Sara Wilkinson, Professor, School of the Built Environment, University of Technology Sydney; Agnieszka Zalejska-Jonsson, Researcher, Division of Building and Real Estate Economics, KTH Royal Institute of Technology, and Sumita Ghosh, Associate Professor in Planning, School of the Built Environment, University of Technology Sydney

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

Waratah is an icon of the Aussie bush (and very nearly our national emblem)



Waratah flowers stand out vividly in the bush.
Tim J Keegan/Flickr, CC BY-SA

Jacob Krauss, UNSW

On one of my first field trips as a young student, searching in sweltering September heat for banksia trees in the bush around Sydney, my eye was caught by a flash of remarkable crimson. Trudging over the red dust, we saw the beautiful waratah flower.

The cone-shaped flower sat upon a green leaf throne, sepals facing upward towards the heavens. The sun lit the red petals just right, and I felt a sense of awe for the flower emblem of New South Wales.




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The rounded flower head and the green razored leaves are iconic. The long stem that can grow up to 4 metres tall allows it to stand above the other vegetation.

The waratah’s long stem lifts it high in the bush understory.
Margaret Donald/Flickr, CC BY-NC-SA

There are five species of waratah flowers, although the species chosen for NSW’s emblem, Telopea speciosissima, is simply known as the New South Wales waratah.

These grow across southeastern Australia along the central coast and up the mountains from the Gibraltar range north of Sydney to Conjola in the south.




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Robert Brown named the genus Telopea in 1810, which derives from the Greek word for “seen from afar” – just as I was able to spot the striking red flowers in the bush. (There is even a botanical journal named Teleopea, after the flower.)

This flower thrives in the shrub understory of open forest and survives despite sandstone soils and volcanic rock. Delicate, the flowers need lots of rainfall. There is also a rare white morph called “Wirrimbira white.” This form was found in the Robertson, NSW near the Kangaloon water catchment.

A beautiful white variation in Sydney’s Royal Botanic Gardens.
Royal Botanic Garden Sydney/Flickr, CC BY-NC-SA

Warratahs have a lignotuber in their root system that allows them to store energy and nutrients. They can regenerate within two years after a wildfire destroys the main flower.

It flowers from September to November, though flowering is highly variable and is sensitive to the environment. The flower is pollinated by birds that feed on its sweet nectar. The plant releases brown leathery pods with large, winged seeds, which germinate readily – making it a popular garden ornament.




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A lovely first alternate for national flower

The waratah flower is a cultural symbol, adorning Australiana ranging from stamps to the state flag of New South Wales. Because it was so common, it helped play a role in developing a colonial Australia’s cultural identity. In fact, it almost beat out the golden wattle as the national emblem back in the 1900s.

There was heated debate, but ultimately the waratah’s bias towards coastal habitat – which meant it was only found on the east coast of Australia and Tasmania – led to its loss. However, in 1962 the flower was proclaimed the official floral emblem of New South Wales.

The wonga pigeon is linked to the waratah in Indigenous Dreamtime stories.
Bernard DUPONT/Flickr, CC BY-SA

There is a rich aboriginal history regarding the flower as well. Gulpilil’s Stories of the Dreamtime tells a story explaining how the white warratah became red. In the story, a female wonga pigeon flew above the tree canopy looking for her lost mate. She was caught by a hawk but broke free, tearing her breast. She landed on a white warratah and her flowing blood stained it red. As she flew from flower to flower, the blood from the wounds drenched all the flowers red.




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If you stick your finger in the flower when it is in bloom you’ll see the “blood” of the pigeon on your finger. The red nectar is sweet, and a medicinal tonic can be made from the red blooms.

It also made a striking impression on European artists in the 18th and 19th centuries. The flower can be seen on collections ranging from vases to statues and stained-glass windows.

An inflatable light installation in Vivid Sydney.
Ashley/Flickr, CC BY-NC-SA

In 1915, Australian botanist R.T. Baker wrote, “The entire plant…lends itself to such a boldness of artistic ideas in all branches of Applied Art that it has few compeers amongst the representatives of the whole floral world.”




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I first spotted the flower on one of my first experiences in the bush near Sydney, hunting banksia for a professor who studies the unique fire ecology of Australian plants in Royal National Park. It is one of my favourite Australian flowers, made even more special by the memory when I first encountered it on that sunny, September day.


Do you love native plants? Sign up to The Conversation’s Beating Around the Bush Facebook group.The Conversation

Jacob Krauss, Graduate Student, UNSW

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

Plants are going extinct up to 350 times faster than the historical norm



Plant extinctions have skyrocketed, driven in large part by land clearing and climate change.
Graphic Node/Unsplash, CC BY-SA

Jaco Le Roux, Macquarie University; Florencia Yanelli, Stellenbosch University; Heidi Hirsch, Stellenbosch University; José María Iriondo Alegría, Universidad Rey Juan Carlos; Marcel Rejmánek, University of California, Davis, and Maria Loreto Castillo, Stellenbosch University

Earth is seeing an unprecedented loss of species, which some ecologists are calling a sixth mass extinction. In May, a United Nations report warned that 1 million species are threatened by extinction. More recently, 571 plant species were declared extinct.

But extinctions have occurred for as long as life has existed on Earth. The important question is, has the rate of extinction increased? Our research, published today in Current Biology, found some plants have been going extinct up to 350 times faster than the historical average – with devastating consequences for unique species.




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Measuring the rate of extinction

“How many species are going extinct” is not an easy question to answer. To start, accurate data on contemporary extinctions are lacking from most parts of the world. And species are not evenly distributed – for example, Madagascar is home to around 12,000 plant species, of which 80% are endemic (found nowhere else). England, meanwhile, is home to only 1,859 species, of which 75 (just 4%) are endemic.

Areas like Madagascar, which have exceptional rates of biodiversity at severe risk from human destruction, are called “hotspots”. Based purely on numbers, biodiversity hotspots are expected to lose more species to extinction than coldspots such as England.

But that doesn’t mean coldspots aren’t worth conserving – they tend to contain completely unique plants.

We are part of an international team that recently examined 291 modern plant extinctions between biodiversity hot- and coldspots. We looked at the underlying causes of extinction, when they happened, and how unique the species were. Armed with this information, we asked how extinctions differ between biodiversity hot- and coldspots.

Unsurprisingly, we found hotspots to lose more species, faster, than coldspots. Agriculture and urbanisation were important drivers of plant extinctions in both hot- and coldspots, confirming the general belief that habitat destruction is the primary cause of most extinctions. Overall, herbaceous perennials such as grasses are particularly vulnerable to extinction.

However, coldspots stand to lose more uniqueness than hotspots. For example, seven coldspot extinctions led to the disappearance of seven genera, and in one instance, even a whole plant family. So clearly, coldspots also represent important reservoirs of unique biodiversity that need conservation.

We also show that recent extinction rates, at their peak, were 350 times higher than historical background extinction rates. Scientists have previously speculated that modern plant extinctions will surpass background rates by several thousand times over the next 80 years.

So why are our estimates of plant extinction so low?

First, a lack of comprehensive data restricts inferences that can be made about modern extinctions. Second, plants are unique in – some of them live for an extraordinarily long time, and many can persist in low densities due to unique adaptations, such as being able to reproduce in the absence of partners.

Let’s consider a hypothetical situation where we only have five living individuals of Grandidier’s baobab (Adansonia grandidieri) left in the wild. These iconic trees of Madagascar are one of only nine living species of their genus and can live for hundreds of years. Therefore, a few individual trees may be able to “hang in there” (a situation commonly referred to as “extinction debt”) but will inevitably become extinct in the future.

Finally, declaring a plant extinct is challenging, simply because they’re often very difficult to spot, and we can’t be sure we’ve found the last living individuals. Indeed, a recent report found 431 plant species previously thought to be extinct have been rediscovered. So, real plant extinction rates and future extinctions are likely to far exceed current estimates.

There is no doubt that biodiversity loss, together with climate change, are some of the biggest challenges faced by humanity. Along with human-driven habitat destruction, the effects of climate change are expected to be particularly severe on plant biodiversity. Current estimates of plant extinctions are, without a doubt, gross underestimates.




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However, the signs are crystal clear. If we were to condense the Earth’s 4.5-billion-year-old history into one calendar year, then life evolved somewhere in June, dinosaurs appeared somewhere around Christmas, and the Anthropocene starts within the last millisecond of New Year’s Eve. Modern plant extinction rates that exceed historical rates by hundreds of times over such a brief period will spell disaster for our planet’s future.The Conversation

Jaco Le Roux, Associate Professor, Macquarie University; Florencia Yanelli, Researcher, Stellenbosch University; Heidi Hirsch, Postdoctoral research fellow, Stellenbosch University; José María Iriondo Alegría, Catedrático de universidad en el área de Botánica, Universidad Rey Juan Carlos; Marcel Rejmánek, Emeritus professor, University of California, Davis, and Maria Loreto Castillo, PhD Candidate, Stellenbosch University

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

The exquisite blotched butterfly orchid is an airy jewel of the Australian landscape



The butterfly orchid grows beautifully.
The Conversation/John Dearlarney

John Dearnaley, University of Southern Queensland

The blotched butterfly orchid (Sarcochilus weinthalii) looks fairly unremarkable when it’s not flowering, generally resembling the far more common orange blossom orchid. But when it flowers, it is exquisite. Dark purple blotches stand out on cream petals, resembling a flock of butterflies come to rest on rainforest trees.

Like the most of its genus, the blotched butterfly orchid is epiphytic, or an air plant: without roots, they absorb water from the air. The leaves are leathery and curved, and appear in groups of three to seven. They usually grow on the horizontal branches of tree hosts in dry rainforests in southern Queensland and northern NSW.




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Australia has 18 unique butterfly orchids, a number of which are under threat. As they are easily grown by orchid fanciers, they are often removed from natural locations and are becoming harder to see in their natural habitat, high up on rainforest trees in hilly terrain.



The Conversation

The genus Sarcochilus was named by Robert Brown, the naturalist on board the Flinders expedition documenting the east coast of Australia in the early 19th century. The name refers to the fleshy labellum, the showy front petal of the flowers.

The blotched butterfly orchid, Sarcochilus weinthalii was first collected by Ferdinand Weinthal, a notable early Australian orchid collector and grower near Toowoomba in southern Queensland in 1903.

My colleagues and I have been trying to learn more about the biology of these beautiful orchids, to help improve conservation efforts. We are studying populations sizes, life cycles, host trees and similar species in an effort to learn more about how and where they grow – and what might be pollinating them.

The total number of plants at our study locations is less than 200 individuals which is concerning. More troubling is now the complete absence of plants from several regular sites for the orchid. The presence of juvenile plants at the study locations suggests the remaining populations could still be viable, albeit with the spectre of inbreeding depression hovering over the smaller groups.

The orchid was quite adaptable to different tree hosts although there was preference for native hydrangea (Cuttsia viburnea) at one site. Plants grew on the southerly (shaded) side of their hosts, at heights varying from more than 4 metres above the forest floor to less than one metre above soil level. These latter plants were growing on a basalt boulder – something never recorded before.

Fungus friends

As part of our research we sampled the roots of the orchid and isolated a symbiotic fungus, identified by DNA analysis. Analysis of the fungal DNA showed something quite striking. Every orchid, from every location, had exactly the same fungus growing in its roots.

When orchid seed was combined with the fungus in the laboratory, plants grew considerably faster than controls. This suggests that both life stages of the plant require the fungus to provide nutrients.

This fungus will be integral for conservation efforts for the species. Strong growth of seedlings in labs and greenhouse will require the fungus to be present. Restoration efforts will need to check for the presence of the fungus to ensure transplanted populations thrive, and to support new seedling growth in re-established orchid populations.

We observed a number of insects visiting flowers of the blotched butterfly orchid, but most of these were small and unlikely to be capable of pollinating the species. Previous research suggests Sarcochilus orchids are pollinated by native bees.

What is the future for the blotched butterfly orchid?

In another species of Sarcochilus we have studied, S. hartmannii, we saw hover flies regularly visiting (and possibly pollinating) these orchids. So it’s feasible these insects are pollinating the blotched butterfly orchid as well – but we need more research to be sure.

Our work also found the orchids are vulnerable to land clearing, an issue that threatens many native Australian plants. Clearing not only destroys individual plants or populations, but provides conduits for the entry of aggressive exotic plant species like cat’s claw and climbing asparagus into fragile ecosystems.




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And unfortunately, the blotched butterfly orchid grows outside national parks (as well as inside them), which makes them hard to protect from orchid collectors. Perhaps weightier fines are necessary to change the minds of recalcitrants who still believe collecting native plant species from the wild is acceptable!The Conversation

John Dearnaley, Associate Professor, University of Southern Queensland

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

Climate explained: why plants don’t simply grow faster with more carbon dioxide in air



Fast-growing plantation trees store less carbon per surface area than old, undisturbed forests that may show little growth.
from http://www.shutterstock.com, CC BY-ND

Sebastian Leuzinger, Auckland 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

Carbon dioxide is a fertiliser for plants, so if its concentration increases in the atmosphere then plants will grow better. So what is the problem? – a question from Doug in Lower Hutt

Rising atmospheric carbon dioxide (CO₂) is warming our climate, but it also affects plants directly.

A tree planted in the 1850s will have seen its diet (in terms of atmospheric carbon dioxide) double from its early days to the middle of our century. More CO₂ generally leads to higher rates of photosynthesis and less water consumption in plants. So, at first sight, it seems that CO₂ can only be beneficial for our plants.

But things are a lot more complex than that. Higher levels of photosynthesis don’t necessarily lead to more biomass production, let alone to more carbon dioxide sequestration. At night, plants release CO₂ just like animals or humans, and if those respiration rates increase simultaneously, the turnover of carbon increases, but the carbon stock doesn’t. You can think of this like a bank account – if you earn more but also spend more, you’re not becoming any richer.

Even if plants grow more and faster, some studies show there is a risk for them to have shorter lifespans. This again can have negative effects on the carbon locked away in biomass and soils. In fact, fast-growing trees (e.g. plantation forests) store a lot less carbon per surface area than old, undisturbed forests that show very little growth. Another example shows that plants in the deep shade may profit from higher levels of CO₂, leading to more vigorous growth of vines, faster turnover, and, again, less carbon stored per surface area.




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Water savings

The effect of CO₂ on the amount of water plants use may be more important than the primary effect on photosynthesis. Plants tend to close their leaf pores slightly under elevated levels of CO₂, leading to water savings. In certain (dry) areas, this may indeed lead to more plant growth.

But again, things are much more complex and we don’t always see positive responses. Research we published in Nature Plants this year on grasslands around the globe showed that while dry sites can profit from more CO₂, there are complex interactions with rainfall. Depending on when the rain falls, some sites show zero or even negative effects in terms of biomass production.

Currently, a net amount of three gigatons of carbon are thought to be removed from the atmosphere by plants every year. This stands against over 11 gigatons of human-induced release of CO₂. It is also unclear what fraction of the three gigatons plants are taking up due to rising levels of CO₂.

In summary, rising CO₂ is certainly not bad for plants, and if we restored forested land at a global scale, we could help capture additional atmospheric carbon dioxide. But such simulations are optimistic and rely on conversion of much needed agricultural land to forests. Reductions in our emissions are unavoidable, and we have very strong evidence that plants alone will not be able to solve our CO₂ problem.




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The Conversation


Sebastian Leuzinger, Associate Professor, Auckland University of Technology

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

The meat-eating bladderwort traps aquatic animals at lightning speed



A hapless animal will swim by, triggering the sensitive hairs at the front of the bladderworts’ bladder, which open like a trap door.
Emma Lupin, Author provided

Greg Leach, Charles Darwin University

Carnivorous plants intrigue people. It’s so out of place to our mental image of what “normal” plants should do.

On the outskirts of Darwin, bladderworts can be found feasting on aquatic animals such as invertebrates, insect larvae, aquatic worms, and water fleas.




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A hapless animal will swim by, triggering the sensitive hairs at the front of the bladderwort’s bladder, which opens like a trap door. The rush of water into the trap carries the animal inside. The door slams shut and digestion starts.

This all happens faster than the eye can see – in less than a millisecond, more than 100 times faster than a Venus flytrap.



The Conversation

The best habitat in all the (wet)land

The bladderwort is just one example of Utricularia. Australia’s Top End contains some 36 species of Utricularia, making it a a global centre for the genus. And the species count is still going up as researchers make new discoveries.

In particular, bladderworts can be found around the Howard River, about 30km east of Darwin, part of a 264 square km area of significant conservation value.




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The Howard River area supports the largest and most continuous stretch of seasonally-flooded sandy wetlands in the Northern Territory, with extensive shallow lagoons and swamps.

The layer of fine sand is between 1 and 10 metres thick. The sand overlays less permeable material such as rock and clay, so the sand becomes completely waterlogged in the wet season. It makes a perfect home for bladderworts.

This highly dynamic environment provides a miniature topography of rises and depressions measured in just centimetres. As well as the alternating monsoonal dry and wet seasons, the topography is overlain with seasonal changes in water levels.




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The species of Utricularia have adapted to different windows of opportunity in these seasonal changes and partition themselves within the habitat, often based on water height.

Within the same small area, species come and go during the season based on their tolerance of these habitat variables. This can be frustrating for the collector and observer, as not all species are found at the one time.

All shapes and sizes

A unifying feature of the Utricularia genus is the suction trap – or “bladder”. But the bladderwort species come in many shapes and sizes.

Flowers, for instance, can vary in size. Some bladderworts have flowers with large nectar-filled spurs. These can grow up to 15 millimetres long and attract insects with a long proboscis (an elongated “snout”). Other bizarre flowers on different bladderwort species have long antennae-like extensions and appear to involve insect mimicry to attract pollinators.




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Other bladderwort species, such as U. odorata, have tall, conspicuous groups of flowers up to 70cm high, with up to 20 bright golden yellow flowers.

And aquatic species of bladderwort have, in some cases, even developed floats around the flowering stalk to keep the flowers above water.

Threats to the Howard Sand Plains

But all is not well on the Howard Sand Plains. The unique landscape is under threat from urban development, recreational misuse, fire, and weed encroachment.

But construction booms in Darwin have created added pressure on the Sand Plains.




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Twenty-two per cent of the sand sheet landscape in this region has been cleared for sand mining, as it holds a huge source of easily accessible, fine, high-grade sand used in concrete for building.

But it’s not all doom and gloom. A project, “Secret World: Carnivorous plants of the Howard sand sheets”, brought artists and scientists out into the field in a workshop setting.

Bladderworts were the inspiration for stunning artworks, leading to education around the species in the local area.
Bladderwort species 1 ….. by John Wolseley/Nomad Art Gallery, Author provided

Scientists explained the significance of the environment, the flora and the threats facing the habitat.

And the artists squelched about the waterlogged habitat and got down and dirty into this Lilliputian world. They set about interpreting the plants and with a diversity of approaches matching the diversity of the bladderworts, they produced a stunning portfolio of artworks.

Artists who explored the waterlogged habitat of the bladderworts produced a stunning portfolio of artworks.
Lunch by Winsome Jobling/Nomad Art Gallery, Author provided



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An education kit produced from the project also took the story into local schools.

The Northern Territory Environment Protection Authority assessed the issues and determined areas of the sand sheets that should be set aside for conservation purposes. The art and science collaboration certainly played a pivotal part in this positive conservation outcome.The Conversation

Greg Leach, Honorary Fellow at Menzies School of Health Research, Charles Darwin University

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