Scientists at work: Sloshing through marshes to see how birds survive hurricanes



A clapper rail with a fiddler crab in its bill.
Michael Gray, CC BY-ND

Scott Rush, Mississippi State University and Mark Woodrey, Mississippi State University

When storms like Huricane Zeta menace the Gulf Coast, residents know the drill: Board up windows, clear storm drains, gas up the car and stock up on water, batteries and canned goods.

But how does wildlife ride out a hurricane? Animals that live along coastlines have evolved to deal with a world where conditions can change radically. This year, however, the places they inhabit have borne the brunt of 10 named storms, some just a few weeks apart.

As wildlife ecologists, we are interested in how species respond to stresses in their environment. We are currently studying how marsh birds such as clapper rails (Rallus crepitans) have adapted to tropical storms along the Alabama and Mississippi Gulf coast. Understanding how they do this entails wading into marshes and thinking like a small, secretive bird.

Least bittern in marsh grass
A least bittern, one of the smallest species of heron.
Michael Gray, CC BY-ND

Mucky and full of life

Coastal wetlands are critically important ecosystems. They harbor fish, shellfish and wading birds, filter water as it flows through and buffer coastlines against flooding.

You wouldn’t choose a Gulf Coast salt marsh for a casual stroll. There are sharp-pointed plants, such as black needlerush​, and sucking mud. In summer and early fall the marshes are oppressively hot and humid. Bacteria and fungi in the mud break down dead material, generating sulfurous-smelling gases. But once you get used to the conditions, you realize how productive these places are, with a myriad of organisms moving about.

Marsh birds are adept at hiding in dense grasses, so it’s more common to hear them than to see them. That’s why we use a process known as a callback survey to monitor for them.

First we play a prerecorded set of calls to elicit responses from birds in the marsh. Then we determine where we think the birds are calling from and visually estimate the distance from the observer to that spot, often using tools such as laser range finders. We also note the type of ecosystem where we detect the birds – for example, whether they’re in a tidal marsh with emergent vegetation or out in the open on mud flats.

Adult clapper rail calling.

Through this process we’ve been able to estimate the distributions of several species in tidal marshes, including clapper rails, least bitterns (Ixobrychus exilis) and seaside sparrows (Ammospiza maritima). We’ve also plotted trends in their abundance and identified how their numbers can change with characteristics of the marsh.

We’ve walked hundreds of miles through marshes to locate nests and to record data such as nest height, density of surrounding vegetation and proximity to standing water, which provides increased foraging opportunities for rails. Then we revisit the nests to document whether they produce young that hatch and eventually leave. Success isn’t guaranteed: Predators may eat the eggs, or flooding could wash them out of the nest and kill the developing embryos inside.

Salt marshes shelter many types of plants, birds, animals, fish and shellfish.

Rails in the grass

Our research currently focuses on clapper rails, which look like slender chickens with grayish-brown feathers and short tails. Like many other marsh birds, they have longish legs and toes for walking across soft mud, and long bills for probing the marsh surface in search of food. They are found year-round along the Atlantic and Gulf coasts.

Clapper rails typically live in tidal marshes where there is vegetation to hide in and plenty of fiddler crabs, among their frequent foods. Because they are generally common and rely on coastal marshes, they are a good indicator of the health of these coastal areas.

Scientist in marsh holding live Clapper Rail
Ecologist Scott Rush with clapper rail, Pascagoula River Marshes, Mississippi.
Mark Woodrey, CC BY-ND

Water levels in tidal marshes change daily, and clapper rails have some adaptations that help them thrive there. They often build nests in areas with particularly tall vegetation to hide them from predators. And they can raise the height of the nest bowl to protect it against flooding during extra-high or “king” tides and storms. The embryos inside their eggs can survive even if the eggs are submerged for several hours.

When a tropical storm strikes, many factors – including wind speed, flooding and the storm’s position – influence how severely it will affect marsh birds. Typically birds ride out storms by moving to higher areas of the marsh. However, if a storm generates extensive flooding, birds in affected areas may swim or be blown to other locations. We saw this in early June when Hurricane Cristobal blew hundreds of clapper rails onto beaches in parts of coastal Mississippi.

Clapper rails hiding under a breakwater
Clapper rails on a Mississippi beach after Hurricane Cristobal in June 2020.
Mark Woodrey, CC BY-ND

In coastal areas immediately to the east of the eye of a tropical cyclone we typically see a drop in clapper rail populations in the following spring and summer. This happens because the counterclockwise rotation of the storms results in the highest winds and storm surge to the north and east of the eye of the storm.

But typically there’s a strong bout of breeding and a population rebound within a year or so – evidence that these birds are quick to adapt. After Hurricane Katrina devastated the Mississippi Gulf Coast in 2005, however, depending on the type of marsh, it took several years for rail populations to return to their pre-Katrina levels.

Now we’re radio-tagging clapper rails and collecting data that allow us to determine the birds’ life spans. This information helps us estimate when large numbers of birds have died – information that we can correlate with events like coastal hurricanes.

2020 Atlantic hurricane paths
Summary map of the 2020 Atlantic hurricane season, updated Oct. 27.
Master0Garfield/Wikipedia

Losing parts

Tropical storms have shaped coastal ecosystems since long before recorded history. But over the past 150 years humans have complicated the picture. Coastal development – draining marshes, building roads and reinforcing shorelines – is altering natural places that support marsh birds.

Clapper rails and other species have evolved traits that help them offset population losses due to natural disasters. But they can do so only if the ecosystems where they live keep providing them with food, breeding habitat and protection from predators. Coastal development, in combination with rising sea levels and larger tropical storms, can act like a one-two punch, making it increasingly hard for marshes and the species that live in them to recover.

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Biologist Paul Ehrlich has compared species at risk to rivets on an airplane. You might not need every rivet in place for the airplane to fly, but would you fly it through a cyclone if you knew that 10% of its rivets were missing? What about 20%, or 30%? At some point, Ehrlich asserts, nature could lose so many species that it becomes unable to provide valuable services that humans take for granted.

We see coastal marshes as an airplane that humans are piloting through storms. As species and ecosystem services are pummeled, rivets are failing. No one knows where or how the aircraft will land. But we believe that preserving marshes instead of weakening them can improve the chance of a smooth landing.The Conversation

Scott Rush, Assistant Professor of Wildlife Ecology and Management, Mississippi State University and Mark Woodrey, Assistant Research Professor, Mississippi State University

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

What ‘The Birdman of Wahroonga’ and other historic birdwatchers can teach us about cherishing wildlife



Shutterstock

Russell McGregor, James Cook University

Under the first coronavirus lockdowns, birdwatching increased tenfold in Australia, with much of it done in and near the watchers’ own backyards. And as Melbourne settles into stage 4 restrictions, we’ll likely see this rise again.

The increase in backyard birding is good news for conservation and can help birds recover from bushfires and other environmental catastrophes. But backyard birding isn’t new, nor is its alliance with conservation.




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Since the turn of the 20th century, when birdwatching as a hobby began in Australia, birders have cherished the birds in their backyards as much as those in outback wilds. Birdwatchers admired wild birds anywhere, for one of their big motivations was — and is — to experience and conserve the wild near home.

Harry Wolstenholme holding a bird in front of him in his garden in Sydney
Pioneering birder Harry Wolstenholme recorded 21 native species nesting in his garden.
Alec Chisholm/National Library of Australia, Author provided

This wasn’t an abstract ambition, but a heartfelt commitment. Birdwatchers have long known that if we are to conserve nature, we need not only the intellectual expertise of science but also an emotional affinity with the living things around us. Birders in Sydney in the 1920s and ‘30s knew this well.

The Birdman of Wahroonga

Harry Wolstenholme, son of the feminist Maybanke Anderson, was an office-bearer in the Royal Australasian Ornithologists’ Union and a keen amateur birdwatcher. In the 1920s, his usual birding site was his own garden in the northern Sydney suburb of Wahroonga.

There, bird life was prolific. Harry recorded 21 native and five introduced species nesting in or near his garden, plus many more avian visitors.

His garden drew a stream of notable birders from the Sydney branch of the ornithologists’ union, such as wildlife photographer Norman Chaffer, naturalist and journalist Alec Chisholm, and businessman Keith Hindwood. (The union members were predominantly male, though with a liberal sprinkling of women, including Perrine Moncrieff who became its first female president in 1932.)

Keith Hindwood in black and white, with a White-eared Honeyeater on his head
Keith Hindwood, with a White-eared Honeyeater on his head, 1929.
Mitchell Library, Author provided

For his closeness to the birds, Harry earned the nickname “The Birdman of Wahroonga”. That suburb still hosts a good range of species, although the bird life is no longer as prolific as in Harry’s day.

Many others birded in city environs and, like Harry, published their suburban ornithological studies in the union journal, The Emu.

In 1932, Alec Chisholm devoted a whole book, Nature Fantasy in Australia, to birding in Sydney and surrounds. Featured on its early pages is a painting by celebrated bird artist Neville Cayley captioned “The Spirit of Sydney: Scarlet Honeyeater at nest in suburban garden”.

Scarlet honeyeater feeding on grevillia nectar
Scarlet honeyeaters can still be spotted in urban parts of Australia.
Shutterstock

The fact this gorgeous little bird was common in Sydney’s gardens exemplifies Chisholm’s theme of urban Australians’ ready access to the wonders of nature. Scarlet Honeyeaters can still be found in Sydney though they are no longer common there.

Mateship with Birds

Like all Chisholm’s nature writings, Nature Fantasy promoted conservation.

Conservation then differed from conservation now, having a stronger aesthetic orientation and less ecological content. Nonetheless, these pioneer conservationists, among whom birdwatchers were prominent, laid the foundations on which environmentalists later built.

Chisholm urged people not merely to observe birds but also, more importantly, to love and cherish them. In his first book in 1922, Mateship with Birds, he urged readers to open their hearts to their avian compatriots and embrace them as friends and fellow Australians.

Jacky winter, a small, pale-coloured bird is perched on a white log.
Early birders believed names of birds like ‘Jacky Winter’ would help us embrace birds as fellow Australians.
Shutterstock

One way of fostering this feeling, Chisholm and his birding contemporaries believed, was to give birds attractive names. For example, “Jacky Winter” struck the right note, and as Chisholm wrote:

it would be a healthy thing if we had more of these familiar names for our birds, bringing as they do, a feeling or sense of intimacy.

While those birders urged people to cultivate an emotional connection with nature, and while most were amateur rather than professional ornithologists, they nonetheless made major contributions to the scientific study of birds.

Science was needed, they realised, but so was feeling. As one reviewer of Nature Fantasy enthused, Chisholm was a naturalist “who in his writings combines with the exact research of a scientist the sensibility of a poet”.




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Birders today

Our city birdscapes have since changed. Some species have dwindled; some have increased. But suburbia still holds a remarkable degree of biodiversity, if only we’re prepared to look.

A woman holds binoculars to her eyes among trees
Lockdown is a great time to try backyard birdwatching.
Shutterstock

The world of the birders of the 1920s and ’30s is gone. Our attitudes toward nature are cluttered with fears unknown in their day, such as climate change. Yet those early birders still have something worthwhile to tell us today: the need to connect emotionally and tangibly with nature.

To hear that message, we need not, and should not, jettison today’s environmental fears. But fear needs complementing with more positive emotions, like love.

Despite — or because of — the prominence of environmental alarms in today’s world, the need to admire and love living things remains as pressing as ever. As birdwatchers have long known, the birds fluttering in our own backyards are adept at fostering those feelings.




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The Conversation


Russell McGregor, Adjunct Professor of History, James Cook University

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

Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)



Shutterstock

Anthea Batsakis, The Conversation and Wes Mountain, The Conversation

This article is part of Flora, Fauna, Fire, a special project by The Conversation that tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Explore the project here and read more articles here.


Before the summer bushfires destroyed vast expanses of habitat, Australia was already in the midst of a biodiversity crisis. Now, some threatened species have been reduced to a handful of individuals – and extinctions are a real possibility.

The Kangaroo Island dunnart, a small marsupial, was listed as critically endangered before the bushfires. Then the inferno destroyed 95% of its habitat.

Prospects for the Banksia Montana mealybug are similarly grim. This flightless insect lives only on one species of critically endangered plant, at a high altitude national park in Western Australia. The fires destroyed 100% of the plant’s habitat.




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And fewer than 100 western ground parrots remained in the wild before last summer, on Western Australia’s south coast. Last summer’s fires destroyed 40% of its habitat.

Fish, crayfish and some frogs are also struggling. After the fires, heavy rain washed ash, fire retardants and dirt into waterways. This can clog and damage gills, and reduces the water’s oxygen levels. Some animals are thought to have suffocated.

Here, dozens of experts tell the stories of the 119 species most in need of help after our Black Summer.

How can I help?

Recovery from Australia’s bushfire catastrophe will be a long road. If you want to help, here are a few places to start.

Donate

Australian Wildlife Conservancy

Bush Heritage Australia

WWF

Birdlife Australia

Also see this list of registered bushfire charities

Volunteer

Parks Victoria

NSW National Parks and Wildlife Service

Queensland Parks and Wildlife Service

Conservation Volunteers Australia

Landcare

The Conversation

Anthea Batsakis, Deputy Editor: Environment + Energy, The Conversation and Wes Mountain, Multimedia Editor, The Conversation

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

What Australian birds can teach us about choosing a partner and making it last



Gisela Kaplan

Gisela Kaplan, University of New England

Love, sex and mate choice are topics that never go out of fashion among humans or, surprisingly, among some Australian birds. For these species, choosing the right partner is a driver of evolution and affects the survival and success of a bird and its offspring.

There is no better place than Australia to observe and study strategies for bird mate choice. Modern parrots and songbirds are Gondwanan creations – they first evolved in Australia and only much later populated the rest of the world.

Here, we’ll examine the sophisticated way some native birds choose a good mate, and make the relationship last.

Rainbow lorikeets form a lifetime bond.
Bobbie Marchant

Single mothers and seasonal flings

For years, research has concentrated on studying birds in which sexual selection may be as simple as males courting females. Males might display extra bright feathers or patterns, perform a special song or dance or, like the bowerbird, build a sophisticated display mound.

In these species, females choose the best mate on the market. But the males do not stick around after mating to raise their brood.




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These reproductive strategies apply only to about tiny proportion of birds worldwide.

Then there are “lovers for a season”, which account for another small percentage of songbirds. Males and females may raise a brood together for one season, then go their separate ways.

These are not real partnerships at all – they’re simply markets for reproduction.

Birds that stick together

But what about the other birds – those that raise offspring in pairs, just as humans often do? Those that form partnerships for more than a season, and in some cases, a lifetime?

More than 90% of birds worldwide fall into this “joint parenting” category – and in Australia, many of them stay together for a long time. Indeed, Australia is a hotspot for these cooperative and long-term affairs.

This staggering figure has no equal in the animal kingdom. Even among mammals, couples are rare; only 5% of all mammals, including humans, pair up and raise kids together.

So how do long-bonding Australian birds choose partners, and what’s their secret to relationship success?

A white headed pigeon pair.
Credit: Gisela Kaplan

Lifelong attachment

The concept of assortative mating is often used to explain how humans form lasting relationships. As the theory goes, we choose mates with similar traits, lifestyle and background to our own.

In native birds that form long-lasting bonds, including butcherbirds, drongos and cockatoos, differences between the sexes are small or non-existent – that is, they are “monomorphic”. Males and females may look alike in size and plumage, or may both sing, build nests and provide equally for offspring.

So, how do they choose each other, if not by colour, song, dance or plumage difference? There’s some research to suggest their choices are based on personality.

Many bird owners and aviculturists would attest that birds have individual personalities. They may, for example, be gentle, tolerant, submissive, aggressive, confident, curious, fearful or sociable.




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Research has not conclusively established which bird personalities are mutually attractive. But so far it seems similarities or familiarity, rather than opposites, attract.

Cockatiel breeders now even use personality assessments similar to those used for show dogs.

There is practical and scientific proof to support this approach. In breeding contexts, seemingly incompatible birds may be forced together. In such cases, they are unlikely to reproduce and may not even interact with each other. For example, research on Gouldian finches has shown that in mismatched pairs, stress hormone levels were elevated over several weeks, which delayed egg laying.

Conversely, well-matched zebra finch pairs have been shown to have greater reproductive success. Well designed experiments have also shown these birds to change human-assigned partners once free to do so, suggesting firm partner preferences.

Zebra finches pair roosting together.
Source Credit: Robyn Burgess

More than just sex

Now to some extraordinary, little-known facets of behaviour in some native birds.

Bird bonds are not always or initially about reproduction. Most cockatoos take five to seven years to mature sexually. Magpies, apostlebirds and white winged choughs can’t seriously think about reproducing until they are five or six years old.

In the interim, they form friendships. Some become childhood sweethearts long before they get “married” and reproduce.

Socially monogamous birds, such as most Australian cockatoos and parrots, pay meticulous attention to each other. They reaffirm bonds by preening, roosting and flying together in search of food and water.

Even not-so-cuddly native songbirds such as magpies or corvids have long term partnerships and fly, feed and roost closely together.

Sulphur-crested cockatoo friends or pair about to land.
Source Robyn Burgess

All in the mind

Bird species that pair up for life, and devote the most time to raising offspring, are generally also the most intelligent (when measured by brain mass relative to body weight).

Such species tend to live for a long time as well – sometimes four times longer than birds of similar weight range in the northern hemisphere.

So why is this? The brain chews up lots of energy and needs the best nutrients. It also needs time to reach full growth. Parental care for a long period, as many Australian birds provide, is the best way to maximise brain development. It requires a strong bond between the parents, and a commitment to raising offspring over the long haul.




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Interestingly, bird and human brains have some similar architecture, and the same range of important neurotransmitters and hormones. Some of these may allow long-term attachments.

Powerful hormones that regulate stress and induce positive emotions are well developed in both humans and birds. These include oxytocin (which plays a part in social recognition and sexual behaviour) and serotonin (which helps regulate and modulate mood, sleep, anxiety, sexuality, and appetite).

The dopamine system also strongly influences the way pair bonds are formed and maintained in primates – including humans – and in birds.

Birds even produce the hormone prolactin, once associated only with mammals. This plays a role in keeping parents sitting on their clutch of eggs, including male birds that share in the brooding.

The power of love

Given the above, one is led to the surprising conclusion that cooperation, and long-term bonds in couples, is as good for birds as it is for humans. The strategy has arguably led both species to becoming the most successful and widely distributed on Earth.

With so many of Australia’s native birds declining in numbers, learning as much as possible about their behaviour, including how they form lasting relationships, is an urgent task.

Much of the information referred to in this article is drawn from Gisela Kaplan’s books Bird Bonds. See also Bird Minds and Tawny FrogmouthThe Conversation

Gisela Kaplan, Emeritus Professor in Animal Behaviour, University of New England

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

Be still, my beating wings: hunters kill migrating birds on their 10,000km journey to Australia


A bar-tailed godwit.
Lucas DeCicco, US Fish and Wildlife Service.

Eduardo Gallo-Cajiao, The University of Queensland

It is low tide at the end of the wet season in Broome, Western Australia. Shorebirds feeding voraciously on worms and clams suddenly get restless.

Chattering loudly they take flight, circling up over Roebuck Bay then heading off for their northern breeding grounds more than 10,000 km away. I marvel at the epic journey ahead, and wonder how these birds will fare.

In my former role as an assistant warden at the Broome Bird Observatory, I had the privilege of watching shorebirds, such as the bar-tailed godwit, set off on their annual migration.

I’m now a conservation researcher at the University of Queensland, focusing on birds. Populations of migratory shorebirds are in sharp decline, and some are threatened with extinction.

We know the destruction of coastal habitats for infrastructure development has taken a big toll on these amazing birds. But a study I conducted with a large international team, which has just been published, suggests hunting is also a likely key threat.

Bar-tailed Godwits and great knots on migration in the Yellow Sea, China.
photo credit: Yong Ding Li

What are migratory shorebirds?

Worldwide, there are 139 migratory shorebird species. About 75 species breed at high latitudes across Asia, Europe, and North America then migrate south in a yearly cycle.

Some 61 migratory shorebird species occur in the Asia-Pacific, within the so-called East Asian-Australasian Flyway. This corridor includes 22 countries – from breeding grounds as far north as Alaska and Siberia to non-breeding grounds as far south as Tasmania and New Zealand. In between are counties in Asia’s east and southeast, such as South Korea and Vietnam.

Map of the East Asian-Australasian Flyway (bounded by blue line) showing schematic migratory movements of shorebirds.
figure credit: Jen Dixon

The bar-tailed godwits I used to observe at Roebuck Bay breed in Russia’s Arctic circle. They’re among about 36 migratory shorebird species to visit Australia each year, amounting to more than two million birds.

They primarily arrive towards the end of the year in all states and territories – visiting coastal areas such as Moreton Bay in Queensland, Eighty Mile Beach in Western Australia, and Corner Inlet in Victoria.

Numbers of migratory shorebirds have been falling for many species in the flyway. The trends have been detected since the 1970s using citizen science data sets.




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Five of the 61 migratory shorebird species in this flyway are globally threatened. Two travel to Australia: the great knot and far eastern curlew.

Threats to these birds are many. They include the loss of their critical habitats along their migration path, off-leash dogs disturbing them on Australian beaches, and climate change likely contracting their breeding grounds.

And what about hunting?

During their migration, shorebirds stop to rest and feed along a network of wetlands and mudflats. They appear predictably and in large numbers at certain sites, making them relatively easy targets for hunters.

Estimating the extent to which birds are hunted over large areas was like completing a giant jigsaw puzzle. We spent many months scouring the literature, obtaining data and reports from colleagues then carefully assembling the pieces.

We discovered that since the 1970s, three-quarters of all migratory shorebird species in the flyway have been hunted at some point. This includes almost all those visiting Australia and four of the five globally threatened species.

Some records relate to historical hunting that has since been banned. For example the Latham’s snipe, a shorebird that breeds in Japan, was legally hunted in Australia until the 1980s. All migratory shorebirds are now legally protected from hunting in Australia.




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We found evidence that hunting of migratory shorebirds has occurred in 14 countries, including New Zealand and Japan, with most recent records concentrated in southeast Asia, such as Indonesia, and the northern breeding grounds, such as the US.

For a further eight, such as Mongolia and South Korea, we could not determine whether hunting has ever occurred.

Our research suggests hunting has likely exceeded sustainable limits in some instances. Hunting has also been pervasive – spanning vast areas over many years and involving many species.

Shorebirds being sold as food in southeast Asia, 2019.
Toby Trung and Nguyen Hoai Bao/BirdLife

Looking ahead

The motivations of hunters vary across the flyway, according to needs, norms, and cultural traditions. For instance, Native Americans in Alaska hunt shorebirds as a food source after winter, and low-income people in Southeast Asia hunt and sell them.

National governments, supported by NGOs and researchers, must find the right balance between conservation and other needs, such as food security.

Efforts to address hunting are already underway. This includes mechanisms such as the United Nations Convention on Migratory Species and the East Asian-Australasian Flyway Partnership. Other efforts involve helping hunters find alternative livelihoods.

Our understanding of hunting as a potential threat is hindered by a lack of coordinated monitoring across the Asia-Pacific.

Additional surveys by BirdLife International, as well as university researchers, is underway in southeast Asia, China, and Russia. Improving hunting assessments, and coordination between them, is essential. Without it, we are acting in the dark.

The author would like to acknowledge the contributions of Professor Richard A. Fuller (University of Queensland), Professor Tiffany H. Morrison (James Cook University), Dr Bradley Woodworth (University of Queensland), Dr Taej Mundkur (Wetlands International), Dr Ding Li Yong (BirdLife International-Asia), and Professor James E.M. Watson (University of Queensland).The Conversation

Eduardo Gallo-Cajiao, PhD Candidate, The University of Queensland

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

B&Bs for birds and bees: transform your garden or balcony into a wildlife haven



Wes Mountain/The Conversation, CC BY-NC

Judith Friedlander, University of Technology Sydney

Just like humans, animals like living near coastal plains and waterways. In fact, cities such as Sydney and Melbourne are “biodiversity hotspots” – boasting fresh water, varied topographies and relatively rich soil to sustain and nourish life.

Recent research showed urban areas can support a greater range of animals and insects than some bushland and rural habitat, if we revegetate with biodiversity in mind.




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Urban regeneration is especially important now, amid unfathomable estimates that more than one billion animals were killed in the recent bushfires. Even before the fires, we were in the middle of a mass extinction event in Australia and around the world.

Losing animals, especially pollinators such as bees, has huge implications for biodiversity and food supplies.

My team and I are creating a B&B Highway – a series of nest boxes, artificial hollows and pollinating plants – in Sydney and coastal urban areas of New South Wales. These essentially act as “bed and breakfasts” where creatures such as birds, bees, butterflies and bats can rest and recharge. Everyday Australians can also build a B&B in their own backyards or on balconies.

City living for climate refugees

I spoke to Charles Sturt University ecologist Dr Watson about the importance of protecting animals such as pollinators during the climate crisis. He said:

The current drought has devastated inland areas – anything that can move has cleared out, with many birds and other mobile animals retreating to the wetter, more temperate forests to the south and east.

So, when considering the wider impacts of these fires […] we need to include these climate refugees in our thinking.

Native birds like the white-winged triller have been spotted in urban areas.
Shutterstock

Many woodland birds such as honeyeaters and parrots have moved in droves to cities, including Sydney, over the last few years because of droughts and climate change, attracted to the rich variety of berries, fruits and seeds.

I also spoke to BirdLife Australia’s Holly Parsons, who said last year’s Aussie Backyard Bird Count recorded other inland birds – such as the white-winged triller, the crimson chat, pied honeyeater, rainforest pigeons and doves – outside their usual range, attracted to the richer food variety in coastal cities.




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What’s more, there have been increased sightings of powerful owls in Sydney and Melbourne, squirrel gliders in Albury, marbled geckos in Melbourne, and blue-tongue lizards in urban gardens across south-east Australia.

With so many birds and pollinators flocking to the cities, it’s important we support them with vegetated regions they can shelter in, such as through the B&B Highway we’re developing.

The B&B Highway: an urban restoration project

B&Bs on our “highway” are green sanctuaries, containing pollinating plants, water and shelters such as beehives and nesting boxes.




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We’re setting up B&Bs across New South Wales in schools and community centres, with plans to expand them in Melbourne, Brisbane and other major cities. In fact, by mid-2020, we’ll have 30 B&Bs located across five different Sydney municipalities, with more planned outside Sydney.

The NSW Department of Education is also developing an associated curriculum for primary and early high school students to engage them in ecosystem restoration.

One of the biodiversity havens the author developed to attract pollinators.
Author provided

If you have space in your garden, or even on a balcony, you can help too. Here’s how.

For birds

Find out what bird species live in your area and which are endangered using the Birdata directory. Then select plants native to your area – your local nursery can help you out here.

The type of plants will vary on whether your local birds feed on insects, nectar, seed, fruit or meat. Use the guide below.



Wes Mountain/The Conversation, CC BY-ND

More tips

Plant dense shrubs to allow smaller birds, such as the superb fairy-wren, to hide from predatory birds.

Order hollows and nesting boxes from La Trobe University to house birds, possums, gliders and bats.

Put out water for birds, insects and other animals. Bird baths should be elevated to enable escape from predators. Clean water stations and bowls regularly.

For native stingless bees

If you live on the eastern seaboard from Sydney northward, consider installing a native stingless beehive. They require very little maintenance, and no permits or special training.

These bees are perfect for garden pollination. Suppliers of bees and hives can be found online – sometimes you can even rescue an endangered hive.

A blue banded bee at a B&B rest stops in NSW.
Author provided

Also add bee-friendly plants – sting or no sting – to your garden, such as butterfly bush, bottlebrush, daisies, eucalyptus and angophora gum trees, grevillea, lavender, tea tree, honey myrtle and native rosemary.

For other insects

Wherever you are in Australia, you can buy or make your own insect hotel. There is no standard design, because our gardens host a wide range of native insects partial to different natural materials.

An insect hotel. Note the holes, at a variety of depths, drilled into the material.
Dietmar Rabich/Wikimedia Commons, CC BY-SA

Building your insect hotel

Use recycled materials (wooden pallets, small wooden box or frames) or natural materials (wood, bamboo, sticks, straw, stones and clay).

Fill gaps in the structure with smaller materials, such as clay and bamboo.

In the wood, drill holes ranging from three to ten millimetres wide for insects to live in. Vary hole depths for different insects – but don’t drill all the way through. They shouldn’t be deeper than 30 centimetres.

Give your hotel a roof so it stays dry, and don’t use toxic paints or varnishes.

Place your insect hotel in a sheltered spot, with the opening facing the sun in cool climates, and facing the morning sun in warmer climates.

Apartment-dwellers can place their insect hotels on a balcony near pot plants. North-facing is often best, but make sure it’s sheltered from harsh afternoon sunshine and heavy rain.The Conversation

Judith Friedlander, Post-graduate Researcher, Institute for Sustainable Futures, University of Technology Sydney

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

These plants and animals are now flourishing as life creeps back after bushfires


Flickr

Kathryn Teare Ada Lambert, University of New England

As the east coast bushfire crisis finally abates, it’s easy to see nothing but loss: more than 11 million hectares of charcoal and ash, and more than a billion dead animals.

But it is heartening to remember that bushfire can be a boon to some plants and animals. We’re already seeing fresh green shoots as plants and trees resprout. Beetles and other insects are making short work of animal carcasses; they will soon be followed by the birds which feed on them.

Australia’s worsening fire regimes are challenging even these tolerant species. But let’s take a look at exactly how life is returning to our forests now, and what to expect in coming months.

Life is returning to fire-ravaged landscapes.
Flickr, CC BY

The science of resprouting

Of course, bushfires kill innumerous trees – but many do survive. Most of us are familiar with the image of bright green sprouts shooting from the trunks and branches of trees such as eucalypts. But how do they revive so quickly?

The secret is a protected “bud bank” which lies behind thick bark, protected from the flames. These “epicormic” buds produce leaves, which enables the tree to photosynthesise – create sugar from the sun so the tree can survive.

Under normal conditions, hormones from shoots higher in the tree suppress these buds. But when the tree loses canopy leaves due to fire, drought or insect attack, the hormone levels drop, allowing the buds to sprout.

Insect influx

This summer’s fires left in their wake a mass of decaying animal carcasses, logs and tree trunks. While such a loss can be devastating for many species – particularly those that were already vulnerable – many insects thrive in these conditions.

For example, flies lay eggs in the animal carcasses; when the maggots hatch, the rotting flesh provides an ample food source. This process helps break down the animal’s body – reducing bacteria, disease and bad smells. Flies are important decomposers and their increased numbers also provide food for birds, reptiles and other species.




Read more:
Looks like an ANZAC biscuit, tastes like a protein bar: Bogong Bikkies help mountain pygmy-possums after fire


Similarly, beetles such as the grey furrowed rosechafer, whose grubs feed on decaying logs and tree trunks, add nutrients to the soil when they defecate which helps plants grow again.

Insects also benefit from the mass of new leaves on trunks and branches. For example, native psyllids – an insect similar to aphids – feed on the sap from leaves and so thrive on the fresh growth.

Animal carcasses are a sad consequence of bushfire, but provide a boon to some insect species.
Sean Davey/AAP

Then come the birds

Once insects start to move back into an area from forested areas nearby, the birds that eat them will follow.

An increase in psyllids encourages honeyeaters – such as bell miners and noisy miners – to return. These birds are considered pests.

A CSIRO study after bushfires in Victoria’s East Gippsland in 1983 found several native bird species – flame and scarlet robins, the buff-rumped thornbill and superb fairy-wren – increased quickly to levels greater than before fire. As shrubs in the understorey regrow, other species will move in, slowly increasing biodiversity.




Read more:
Not all weeds are villains. After a fire, some plants – even weeds – can be better than none


Since the recent bushfire in woodland near Moonbi in New South Wales, numerous bird species have returned. On a visit over this past weekend, I observed currawongs landing in the canopy, saw fairy wrens darting in and out of foliage sprouting from the ground, and heard peep wrens in tufts of foliage on bark and high branches.

Honeyeaters moved between burnt and intact trees on the edge of the blackened forest and butterflies visited new plants flowering after recent rain.

The presence of the currawong, while a pest species, shows birdlife is returning to the bush.
Flickr, CC BY

Weeds can help

Weeds usually benefit when fire opens up the tree canopy and lets in light. While this has a downside – preventing native plants from regenerating – weeds can also provide cover for native animal species.

A study I co-authored in 2018 found highly invasive Lantana camara provided habitat for small mammals such as the brown rat in some forests. Mammal numbers in areas where lantana was present were greater than where it was absent.

Lantana often grows quickly after fire due to the increase in light and its ability to suppress other plant growth.

Lantana provides cover for animal species.
Flickr, CC BY

Is there hope for threatened species?

Generalist species – those that thrive in a variety of environments – can adapt to burnt forest. But specialist species need particular features of an ecosystem to survive, and are far less resilient.

The critically endangered Leadbeater’s possum lives only in small pockets of forest in Victoria.

It requires large fires to create a specific habitat: big dead trees provide hollows for shelter and nesting, and insects feeding on burnt wood and carcasses provide a food source.

But for the Leadbeater’s possum to benefit from the fire regime, bushfires should be infrequent – perhaps every 75 years – allowing time for the forest to grow back. If fires are too frequent, larger trees will not have time to establish and hollows will not be created, causing the species’ numbers to decline.

Similarly in NSW, at least 50% and up to 80% of the habitat of threatened species such as the vulnerable rufous scrub-bird was burnt in the recent fires, an environmental department analysis found.

Looking ahead

Only time will tell whether biodiversity in these areas is forever damaged, or will return to its former state.

Large fires may benefit some native species but they also provide food and shelter for predatory species, such as feral cats and foxes. The newly open forest leaves many native mammals exposed, changing the foodweb, or feeding relationships, in an ecosystem.

This means we may see a change in the types of birds, reptiles and mammals found in forests after the fires. And if these areas don’t eventually return to their pre-fire state, these environments may be changed forever – and extinctions will be imminent.




Read more:
Fire almost wiped out rare species in the Australian Alps. Feral horses are finishing the job


The Conversation


Kathryn Teare Ada Lambert, Adjunct Lecturer/ Ecologist, University of New England

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

Buildings kill millions of birds. Here’s how to reduce the toll



These birds were killed by flying into a set of surveyed buildings in Washington DC in 2013.
USGS Bee Inventory and Monitoring Lab/Flickr

Norman Day, Swinburne University of Technology

As high-rise cities grow upwards and outwards, increasing numbers of birds die by crashing into glass buildings each year. And of course many others break beaks, wings and legs or suffer other physical harm. But we can help eradicate the danger by good design.

Most research into building-related bird deaths has been done in the United States and Canada, where cities such as Toronto and New York City are located on bird migration paths. In New York City alone, the death toll from flying into buildings is about 200,000 birds a year.

Across the US and Canada, bird populations have shrunk by about 3 billion since 1970. The causes include loss of habitat and urbanisation, pesticides and the effects of global warming, which reduces food sources.

An estimated 365 million to 1 billion birds die each year from “unnatural” causes like building collisions in the US. The greatest bird killer in the US remains the estimated 60-100 million free-range cats that kill up to 4 billion birds a year. Australia is thought to have up to 6 million feral cats.




Read more:
For whom the bell tolls: cats kill more than a million Australian birds every day


But rampant global urbanisation is putting the reliance on glass buildings front-of-stage as an “unnatural” cause of bird deaths, and the problem is growing exponentially.

In the line of flight

Most birds fly at around 30-50km/h, with falcons capable of up to 200km/h. When migrating, birds generally spend five to six hours flying at a height of 150 metres, sometimes much higher.

And that’s where the problems start with high-rise buildings. Most of them are much taller than the height at which birds fly. In Melbourne, for example, Australia 108 is 316 metres, Eureka 300 metres, Aurora 270 metres and Rialto 251 metres. The list is growing as the city expands vertically.

The paradigm of high-rise gothams, New York City, has hundreds of skyscrapers, most with fully glass, reflective walls. One World Trade is 541 metres high, the 1931 Empire State is 381 metres (although not all glass) and even the city’s 100th-highest building, 712 Fifth Avenue, is 198 metres.

To add to the problems of this forest of glass the city requires buildings to provide rooftop green places. These attract roosting birds, which then launch off inside the canyons of reflective glass walls – often mistaking these for open sky or trees reflected from behind.

Reflections of trees and sky lure birds into flying straight into buildings.
Frank L Junior/Shutterstock

A problem of lighting and reflections

Most cities today contain predominantly glass buildings – about 60% of the external wall surface. These buildings do not rely on visible frames, as in the past, and have very limited or no openable windows (for human safety reasons). They are fully air-conditioned, of course.




Read more:
Glass skyscrapers: a great environmental folly that could have been avoided


Birds cannot recognise daylight reflections and glass does not appear to them to be solid. If it is clear they see it as the image beyond the glass. They can also be caught in building cul-de-sac courtyards – open spaces with closed ends are traps.

At night, the problem is light from buildings, which may disorientate birds. Birds are drawn to lights at night. Glass walls then simply act as targets.

Some species send out flight calls that may lure other birds to their death.

White-throated Sparrows collected in a University of Michigan-led study of birds killed by flying into buildings lit up at night in Chicago and Cleveland.
Roger Hart, University of Michigan/Futurity, CC BY



Read more:
Want to save millions of migratory birds? Turn off your outdoor lights in spring and fall


We can make buildings safer for birds

Architectural elements like awnings, screens, grilles, shutters and verandas deter birds from hitting buildings. Opaque glass also provides a warning.

Birds see ultraviolet light, which humans cannot. Some manufacturers are now developing glass with patterns using a mixed UV wavelength range that alerts birds but has no effect on human sight.

New York City recently passed a bird-friendly law requiring all new buildings and building alterations (at least under 23 metres tall, where most fly) be designed so birds can recognise glass. Windows must be “fritted” using applied labels, dots, stripes and so on.

The search is on for various other ways of warning birds of the dangers of glass walls and windows.

Combinations of methods are being used to scare or warn away birds from flying into glass walls. These range from dummy hawks (a natural enemy) and actual falcons and hawks, which scare birds, to balloons (like those used during the London Blitz in the second world war), scary noises and gas cannons … even other dead birds.

Researchers are using lasers to produce light ray disturbance in cities especially at night and on dark days.

Noise can be effective, although birds do acclimatise if the noises are produced full-time. However, noise used as a “sonic net” can effectively drown out bird chatter and that interference forces them to move on looking for quietness. The technology has been used at airports, for example.

A zen curtain developed in Brisbane has worked at the University of Queensland. This approach uses an open curtain of ropes strung on the side of buildings. These flutter in the breeze, making patterns and shadows on glass, which birds don’t like.

These zen curtains can also be used to make windows on a house safer for birds. However, such a device would take some doing for the huge structures of a metropolis.

More common, and best adopted at the design phase of a building, is to mark window glass so birds can see it. Just as we etch images on glass doors to alert people, we can apply a label or decal to a window as a warning to birds. Even using interior blinds semi-open will deter birds.

Birds make cities friendlier as part of the shared environment. We have a responsibility to provide safe flying and security from the effects of human habitation and construction, and we know how to achieve that.


This article has been updated to correct the figure for the estimated number of birds killed by the cats in the US to “up to 4 billion”, not 4 million.The Conversation

Norman Day, Lecturer in Architecture, Practice and Design, Swinburne University of Technology

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

Six million hectares of threatened species habitat up in smoke



At least 250 threatened species have had their habitat hit by fires.
Gena Dray

Michelle Ward, The University of Queensland; Aaron Greenville, University of Sydney; April Reside, The University of Queensland; Ayesha Tulloch, University of Sydney; Brooke Williams, The University of Queensland; Emily Massingham, The University of Queensland; Helen Mayfield, The University of Queensland; Hugh Possingham, The University of Queensland; James Watson, The University of Queensland; Jim Radford, La Trobe University, and Laura Sonter, The University of Queensland

More than one billion mammals, birds, and reptiles across eastern Australia are estimated to have been affected by the current fire catastrophe.

Many animals and plants have been incinerated or suffocated by smoke and ash. Others may have escaped the blaze only to die of exhaustion or starvation, or be picked off by predators.



But even these huge losses of individual animals and plants do not reveal the full scale of impact that the recent fires have had on biodiversity.

Plants, invertebrates, freshwater fish, and frogs have also been affected, and the impact of the fires is likely to be disproportionately greater for threatened species.




Read more:
A season in hell: bushfires push at least 20 threatened species closer to extinction


To delve deeper into the conservation impact, we used publicly available satellite imagery to look at the burnt areas (up to January 7, 2020) and see how they overlapped with the approximate distributions of all the threatened animals and plants listed under the Environment Protection and Biodiversity Conservation Act.

We restricted our analysis to the mediterranean and temperate zone of south-east and south-west Australia.

The bad news

We found that 99% of the area burned in the current fires contains potential habitat for at least one nationally listed threatened species. We conservatively estimate that six million hectares of threatened species habitat has been burned.



Given that many fires are still burning and it is not yet clear how severe the burning has been in many areas, the number of species affected and the extent of the impact may yet change.

What we do know is that these species are already on the brink of extinction due to other threats, such as land clearing, invasive species, climate change, disease, or previous fires.

Approximately 70 nationally threatened species have had at least 50% of their range burnt, while nearly 160 threatened species have had more than 20% of their range burnt.

More threatened plants have been affected than other groups: 209 threatened plant species have had more than 5% of their range burnt compared to 16 mammals, ten frogs, six birds, four reptiles, and four freshwater fish.


Author supplied

Twenty-nine of the 30 species that have had more than 80% of their range burnt are plants. Several species have had their entire range consumed by the fires, such as the Mountain Trachymene, a fire-sensitive plant found in only four locations in the South Eastern Highlands of NSW.

Other species that have been severely impacted include the Kangaroo Island dunnart and the Kangaroo Island glossy black cockatoo. These species’ entire populations numbered only in the hundreds prior to these bushfires that have burned more than 50% of their habitat.

The Kangaroo Island glossy black cockatoo has had more than 50% its habitat impacted by fire.
Mike Barth

Glossy black cockatoos have a highly specialised diet. They eat the seeds of the drooping sheoak (Allocasuarina verticillata). These trees may take anywhere from 10 to 50 years to recover enough to produce sufficient food for the black cockatoos.

The populations of many species will need careful management and protection to give their habitats enough time to recover and re-supply critical resources.

The figures above do not account for cumulative impacts of previous fires. For example, the critically endangered western ground parrot had around 6,000 hectares of potential habitat burnt in these fires, which exacerbates the impact of earlier extensive fires in 2015 and early 2019.

Threatened species vary in their ability to cope with fire. For fire-sensitive species, almost every individual dies or is displaced. The long-term consequences are likely to be dire, particularly if vegetation composition is irrevocably changed by severe fire or the area is subject to repeat fires.

More than 50% of the habitat of several species known to be susceptible to fire has been burnt – these include the long-footed potoroo and Littlejohn’s tree frog.

The endangered long-footed potoroo has had more than 50% of its potential habitat impacted by fire.
George Bayliss

Some species are likely to thrive after fire. Indeed, of the top 30 most impacted species on our list, almost 20% will likely flourish due to low competition in their burnt environments – these are all re-sprouting plants. Others will do well if they are not burnt again before they can set seed.

Rising from the ashes

For fire-sensitive threatened species, these fires could have substantially increased the probability of extinction by virtue of direct mortality in the fires or reducing the amount of suitable habitat. However, after the embers settle, with enough investment and conservation actions, guided by evidence-based science, it may be possible to help threatened species recover.

For species on the brink of extinction, insurance populations need to be established. Captive breeding and release can complement wild populations, as occurs for the regent honeyeater.
Dean Ingwersen / BirdLife Australia

Protection and conservation-focussed management of areas that have not burned will be the single most important action if threatened species are to have any chance of persistence and eventual recovery.

Management of threatening processes (such as weeds, feral predators, introduced herbivores, and habitat loss through logging or thinning) must occur not just at key sites, but across the landscapes they sit in. Maintaining only small pockets of habitat in a landscape of destruction will lock many species on the pathway to extinction.

In some cases, rigorous post-fire restoration will be necessary to allow species to re-colonise burnt areas. This may include intensive weed control and assisted regeneration of threatened flora and specific food sources for fauna, installing nest boxes and artificial cover, or even targeted supplementary feeding.

Unconventional recovery actions will be needed because this unique situation calls for outside-the-box thinking.




Read more:
The science of drought is complex but the message on climate change is clear


Playing the long game

These fires were made larger and more severe by record hot, dry conditions. Global temperatures have so far risen by approximately 1°C from pre-industrial levels.

Current projections indicate that we are on track for a 3°C increase. What will that look like?

We are in a moment of collective grief for what has been lost. A species lost is not just a word on a page, but an entire world of unique traits, behaviours, connections to other living things, and beauty.

These losses do not need to be in vain. We have an opportunity to transform our collective grief into collective action.

Australians are now personally experiencing climate impacts in an unprecedented way. We must use this moment to galvanise our leaders to act on climate change, here in Australia and on the world stage.

The futures of our beloved plants and animals, and our own, depend on it.The Conversation

Michelle Ward, PhD Candidate, The University of Queensland; Aaron Greenville, Lecturer in Spatial Agricultural and Environmental Sciences, University of Sydney; April Reside, Researcher, Centre for Biodiversity and Conservation Science, The University of Queensland; Ayesha Tulloch, DECRA Research Fellow, University of Sydney; Brooke Williams, PhD Candidate, The University of Queensland; Emily Massingham, PhD Student, The University of Queensland; Helen Mayfield, Postdoctoral Research Fellow School of Earth and Environmental Sciences, The University of Queensland; Hugh Possingham, Professor, The University of Queensland; James Watson, Professor, The University of Queensland; Jim Radford, Principal Research Fellow, Research Centre for Future Landscapes, La Trobe University, and Laura Sonter, PhD Candidate in Global Environmental Change, The University of Queensland

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

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



Invertebrates out greatly outnumber mammals everywhere, including in bushfire zones.
Michael Lee, CC BY-NC-ND

Mike Lee, Flinders University

The scale and speed of the current bushfire crisis has caught many people off-guard, including biodiversity scientists. People are scrambling to estimate the long-term effects. It is certain that many animal species will be pushed to the brink of extinction, but how many?

One recent article suggested 20 to 100, but this estimate mostly considers large, well-known species (especially mammals and birds).

A far greater number of smaller creatures such as insects, snails and worms will also be imperilled. They make up the bulk of biodiversity and are the little rivets holding ecosystems together.




Read more:
A season in hell: bushfires push at least 20 threatened species closer to extinction


But we have scant data on how many species of small creatures have been wiped out in the fires, and detailed surveys comparing populations before and after the fires will not be forthcoming. So how can we come to grips with this silent catastrophe?

This native bee (Amphylaeus morosus) has been devastated by the bushfires across much of its range. It plays important roles in pollinating plants and as part of the food web, but has no common name, and its plight is so far unheralded.
Reiner Richter https://www.ala.org.au/

Using the information that is available, I calculate that at least 700 animal species have had their populations decimated – and that’s only counting the insects.

This may sound like an implausibly large figure, but the calculation is a simple one. I’ll explain it below, and show you how to make your own extinction estimate with only a few clicks of a calculator.

Using insects to estimate true extinction numbers

More than three-quarters of the known animal species on Earth are insects. To get a handle on the true extent of animal extinctions, insects are a good place to start.

My estimate that 700 insect species are at critical risk involves extrapolating from the information we have about the catastrophic effect of the fires on mammals.

We can work this out using only two numbers: A, how many mammal species are being pushed towards extinction, and B, how many insect species there are for each mammal species.

To get a “best case” estimate, I use the most conservative estimates for A and B below, but jot down your own numbers.

How many mammals are critically affected?

A recent Time article lists four mammal species that will be severely impacted: the long-footed potoroo, the greater glider, the Kangaroo Island dunnart, and the black-tailed dusky antechinus. The eventual number could be much greater (e.g the Hastings River mouse, the silver-headed antechinus), but let’s use this most optimistic (lowest) figure (A = 4).

Make your own estimate of this number A. How many mammal species do you think would be pushed close to extinction by these bushfires?

We can expect that for every mammal species that is severely affected there will be a huge number of insect species that suffer a similar fate. To estimate exactly how many, we need an idea of insect biodiversity, relative to mammals.

How many insect species are out there, for each mammal species?

The world has around 1 million named insect species, and around 5,400 species of land mammals.

So there are at least 185 insect species for every single land mammal species (B = 185). If the current bushfires have burnt enough habitat to devastate 4 mammal species, they have probably taken out around 185 × 4 = 740 insect species in total. Along with many species of other invertebrates such as spiders, snails, and worms.

There are hundreds of insect species for every mammal species.
https://imgbin.com/

For your own value for B, use your preferred estimate for the number of insect species on earth and divide it by 5,400 (the number of land mammal species).

One recent study suggests there are at least 5.5 million species of insects, giving a value of B of around 1,000. But there is reason to suspect the real number could be much greater.




Read more:
The Earth’s biodiversity could be much greater than we thought


How do our estimates compare?

My “best case” values of A = 4 and B = 185 indicate at least 740 insect species alone are being imperilled by the bushfires. The total number of animal species impacted is obviously much bigger than insects alone.

Feel free to perform your own calculations. Derive your values for A and B as above. Your estimate for the number of insect species at grave risk of extinction is simply A × B.

Post your estimate and your values for A and B please (and how you got those numbers if you wish) in the Comments section and compare with others. We can then see what the wisdom of the crowd tells us about the likely number of affected species.




Read more:
How to unleash the wisdom of crowds


Why simplistic models can still be very useful

The above calculations are a hasty estimate of the magnitude of the current biodiversity crisis, done on the fly (figuratively and literally). Technically speaking, we are using mammals as surrogates or proxies for insects.

To improve these estimates in the near future, we can try to get more exact and realistic estimates of A and B.

Additionally, the model itself is very simplistic and can be refined. For example, if the average insect is more susceptible to fire than the average mammal, our extinction estimates need to be revised upwards.

Also, there might be an unusually high (or low) ratio of insect species compared to mammal species in fire-affected regions. Our model assumes these areas have the global average – whatever that value is!

And most obviously, we need to consider terrestrial life apart from insects – land snails, spiders, worms, and plants too – and add their numbers in our extinction tally.

Nevertheless, even though we know this model gives a huge underestimate, we can still use it to get an absolute lower limit on the magnitude of the unfolding biodiversity crisis.

This “best case” is still very sad. There is a strong argument that these unprecedented bushfires could cause one of biggest extinction events in the modern era. And these infernos will burn for a while longer yet.The Conversation

Mike Lee, Professor in Evolutionary Biology (jointly appointed with South Australian Museum), Flinders University

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