Monarch butterflies raised in captivity can still join the migration

Migrating monarch butterflies rest at Pismo Beach, Calif. on their way to Mexico.
(Shutterstock)

Alana Wilcox, University of Guelph and Ryan Norris, University of GuelphEach year, thousands of hobbyists and educators across North America collect monarch eggs or caterpillars from the wild to raise indoors and patiently wait for butterflies to emerge. Raising monarch butterflies indoors has become an increasingly popular activity that can have numerous benefits.

Captively reared monarchs provide a unique opportunity for people to learn about the complex life cycle of butterflies and, at the same time, help raise awareness about monarch conservation. However, rearing monarchs (and other butterflies) must be done responsibly and in moderation to make sure that it does not have a negative effect on the population.

Monarch butterflies undergo a multi-generational migration in spring and summer that will bring them as far north as Canada and then, in the fall, a new generation of monarchs undergo a unique transformation that prepares them for a single-bout long-distance migration south. These larger, stronger monarch butterflies will travel more than 4,500 kilometres to congregate and overwinter by the millions in the tree canopies high in the Sierra Madre Mountains of Mexico.

A PBS Nature special on overwintering monarch butterflies in Mexico.

Population decline

The overwintering population of eastern monarch butterflies, however, has been dwindling from an occupancy level of 44.95 hectares in 1997 to 14.95 hectares in 2019 to five hectares this year. Some causes of this decline are thought to be loss of milkweed on which caterpillars feed, long-term changes in climate and deforestation at their overwintering sites. This has caused concern about the likelihood of extinction and the loss of the migratory phenomenon.

Rearing monarchs indoors has been touted as a way to help bolster population numbers and mitigate declines. In reality, indoor rearing probably does little to supplement the wild population, but arguably goes a long way towards awareness and education.

The practice of indoor rearing is not without controversy and has been considered potentially harmful due to the negative impact it could have on butterfly health and the risk it could pose to the butterflies’ ability to migrate to Mexico.

However, our recent research provides some evidence that monarchs raised indoors may still be able to migrate south to their overwintering grounds.

Monarch butterfly with a radio-tracking tag.
(Wilcox), Author provided

Disoriented butterflies

Our team at the University of Guelph raised monarch caterpillars on milkweed indoors in controlled environmental conditions that approximated what monarchs would experience naturally in the wild. Once butterflies emerged from their cocoons, they were tested in a flight simulator, a large open vessel with a digital sensor that recorded which direction the monarchs attempted to fly.

The results from this experiment were consistent with previous research showing that indoor-reared monarchs, on average, did not orient in the proper direction for migration to Mexico.

Monarch butterflies’ inability to orient in the flight simulator could be the result of a lack of exposure to natural and direct sunlight during development. Many animals are equipped with an internal clock that tells the animal when to perform certain activities. For monarch butterflies, this internal clock is located in their antennae and, when coupled with visual information on the sun’s position, tells the monarch which direction it should fly each fall.

Monarch butterflies hatched in captivity but released in the wild were found to join the southward migration.
(Wilcox, Newman, Raine, Mitchell and Norris), Author provided

Recalibration in natural light

Given this, our research team went one step further to determine if indoor-reared monarchs exposed to natural environmental conditions and sunlight after they were released could calibrate their internal compass and fly south.

To do so, our team attached tiny radio transmitters to a second group of indoor-reared monarchs and released the butterflies into the wild. The radio transmitters emit a signal during migration and, if a monarch flies close enough, can be received at one of several hundred automatic radio receiving towers scattered across North America, called the Motus telemetry array.

We detected 29 butterflies at the beginning of migration and found that, given some time outdoors, these butterflies were able to get their bearings and fly southward. This suggests that under certain controlled conditions, raising monarchs indoors may not affect their orientation and ability to start migration.

Indoor rearing offers a valuable tool for learning and fostering a connection to nature. Our results help curb concern that indoor rearing negatively impacts monarch orientation.

While more research needs to be conducted to determine how monarchs perform under different indoor conditions and at different rearing locations in North America, our research suggests that monarch enthusiasts may be able to continue enjoying the wonderful experience of raising these butterflies at home.

Alana Wilcox, Researcher, Conservation biology, University of Guelph and Ryan Norris, Associate Professor, Member of the Royal Society of Canada’s College of New Scholars, Artists and Scientists, University of Guelph

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

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Bushfire survivors just won a crucial case against the NSW environmental watchdog, putting other states on notice

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Laura Schuijers, The University of MelbourneThis week was another big one in the land of climate litigation.

On Thursday, a New South Wales court compelled the state Environment Protection Authority (EPA) to take stronger action to reduce greenhouse gas emissions. It’s the first time an Australian court has ordered a government organisation to take more meaningful action on climate change.

The case challenging the EPA’s current failures was brought by a group of bushfire-affected Australians. The group’s president said the ruling means those impacted by bushfires can rebuild their homes, lives, and communities, with the confidence the EPA will also work to do its part by addressing emissions.

The group’s courtroom success shows citizens can play an important role in bringing about change. And it continues a recent trend of successful climate cases that have held government and private sector actors to account for their responsibility to help prevent climate-related harms.

Who are the bushfire survivors?

Members of the group, the Bushfire Survivors for Climate Action, identify as survivors, firefighters and local councillors impacted by bushfires and the continued threat of bushfire posed by climate change.

Their stories paint a picture of devastating loss, and fear of what might be to come. One member, who lost her home, tells of harrowing hours looking for friends and family amid a dark, alien moonscape. Another, a volunteer firefighter, describes the smell of charred and burnt flesh and the silence of the incinerated forests that haunted him.

Fiona Lee, a member of the Bushfire Survivors group, stands in the ruins of her home after a bushfire swept through.
Bushfire Survivors for Climate Action

The group argues that because the NSW EPA is required, by law, to protect the environment through quality objectives, guidelines and policies, these instruments also need to cover greenhouse gas emissions.

Their reasoning is hard to fault: climate change is one of the environment’s most significant threats. In today’s world, you can’t protect the environment without addressing climate change.

To establish this point, the bushfire survivors presented the latest report from the Intergovernmental Panel on Climate Change, which was released while the trial was being heard. The report describes how the temperature rise in Australia could exceed the global average, and predicts increasingly hotter and drier conditions.

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Read more:
Climate change has already hit Australia. Unless we act now, a hotter, drier and more dangerous future awaits, IPCC warns

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An unperformed duty

The EPA’s statutory duty to protect the environment was already known before the litigation began. That’s because the duty is contained within the EPA’s own legislation.

The Bushfire Survivors brought their case to the NSW Land and Environment Court.
Bushfire Survivors for Climate Action

The EPA protects the environment from other types of pollutants by issuing environment protection licences, monitoring compliance, and imposing fines and clean-up orders. The bushfire survivors were seeking to force the EPA to address greenhouse gas emissions as well.

The EPA unsuccessfully tried to establish it is not required to address any specific environmental problem — i.e. climate change. And it argued that even if it is, it has already done enough.

But the court agreed with the bushfire survivors that the EPA’s instruments already in place aren’t sufficient, leaving the duty “unperformed”.

The court didn’t specify exactly how the EPA should remedy the fact it isn’t adequately addressing climate change, meaning the EPA can decide how it develops its own quality objectives, guidelines and policies, in a way that leads to fewer emissions. It is not the court’s job to make policy.

The EPA might, for example, target the highest-emitting industries and activities, via controls or caps on greenhouse gases.

Importantly, however, the court said the EPA doesn’t have to match its actions with a particular climate scenario, such as a global temperature rise of 1.5℃.

Other states on notice

Although this ruling is specific to NSW, other state environment protection authorities also have legal objectives to protect the environment.

This case may cause other Australian environmental authorities to consider whether their regulatory approaches match what the law requires them to do. This might include a responsibility to protect the environment from climate change.

Another thing we know from the NSW case is that simply having policies and strategies isn’t enough.

The court made it clear aspirational and descriptive plans won’t cut the mustard if there’s nothing to “set any objectives or standards, impose any requirements, or prescribe any action to be taken to ensure the protection of the environment”.

The EPA tried to point to NSW’s Climate Change Framework and Net Zero Plan as a way of showing climate change action. But neither of these was developed by the EPA.

The EPA also presented documents it did develop, including a document about landfill guidelines, a fact sheet on methane, and a regulatory strategy highlighting climate change as a challenge for the EPA.

The court found these weren’t enough to address the threat of climate change and discharge the EPA’s duty, calling the regulatory strategy’s description of climate change “general and trite”.

An Australian first, but not an anomaly

Globally, climate litigation is playing a role in filling gaps in domestic climate governance. Cases in Europe, North and South America, and elsewhere have led to courts pushing governments to do more.

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Read more:
In a landmark judgment, the Federal Court found the environment minister has a duty of care to young people

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One of the world’s first major successful climate change cases, Massachusetts v EPA, was similar to the bushfire survivors’ case. Back in 2007, the state of Massachusetts, along with other US states, sued the federal US EPA. They were seeking to force regulatory action on greenhouse gas emissions, and a recognition of carbon dioxide as a pollutant under the Clean Air Act.

While the NSW case comes 14 years after the US case, there has been plenty of courtroom action in Australia in the meantime, with cases against the financial sector, government actors, and corporations.

The Australasian Centre for Corporate Responsibility just filed a lawsuit against Santos.
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In fact, on the same morning as the bushfire survivors’ case, a lawsuit was filed against oil and gas giant Santos in the Federal Court.

The Australasian Centre for Corporate Responsibility will argue statements made in Santos’s annual report are misleading and deceptive. These statements include that natural gas is a “clean fuel” and that it has a “clear and credible” plan to achieve net-zero emissions by 2040.

Climate change is an inevitable problem, and one that will be costly. Lawsuits seeking to force action now aim to limit how great the costs will be down the track. By targeting those most responsible, they are a means of seeking justice.

Laura Schuijers, Research Fellow in Environmental Law, The University of Melbourne

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

What Greenland’s record-breaking rain means for the planet

Willow Hallgren, Griffith UniversityFor three days this month, 7 billion tonnes of rain fell across Greenland — the largest amount since records began in 1950. It’s also the first time since then that rain, not snow, fell on Greenland’s highest peak.

This is alarming. Greenland’s ice sheet is the second largest on the planet (after Antarctica) and any rain falling on its surface accelerates melting. By August 15, the amount of ice lost was seven times greater than is normal for mid-August.

This is just the latest extreme climate event on the island, which sits in the North Atlantic Ocean. In a single day in July this year, the amount of ice that melted in Greenland would have covered the US state of Florida with 5 centimetres of water. And last October, research showed ice in Greenland is melting faster than at any other time in the past 12,000 years.

Melting in Greenland threatens to significantly hamper humanity’s efforts to mitigate climate change. That’s because, after a certain point, it may create catastrophic “feedback loops”. Let’s look at the issue in more detail.

Rising temperatures in the Arctic

Greenland’s vast ice sheet comprises almost 1.7 million square kilometres of glacial land ice. It covers most of the territory and contains enough ice to raise sea levels by more than 7 metres if melted.

The Greenland and Antarctica ice sheets lost a combined 6.4 trillion tonnes of ice between 1992 and 2017. Melting in Greenland has contributed to 60% (17.8 millimetres) of the Earth’s overall sea-level rise due to melting ice sheets, even though Greenland is much smaller than Antarctica.

This may be partly because half of Greenland’s melting is the result of rising air temperatures, which cause surface melting. In Antarctica, most ice loss is from ocean water melting glaciers that spill from land into the sea. And the rate of ice loss in both Greenland and Antarctica is accelerating — increasing sixfold since the 1990s.

Rain falling on ice exacerbates this process. So what’s behind the recent unprecedented weather?

Temperatures in the Arctic are rising twice as quickly as the rest of the planet for a number of reasons, including changes in cloud cover and water vapour, the reflectivity of the surface, and how weather systems transport energy from the tropics to the polar regions. This has made extreme weather events more common.

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Climate explained: why is the Arctic warming faster than other parts of the world?

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In recent years in Greenland, rain has fallen further north, and more rain has fallen in winter. This is not normal for these regions, which usually get snow, not rain, in below-freezing temperatures.

This month’s rain is the result of warm, moist air flowing up from south-west of Greenland and remaining for several days. In the morning of August 14, temperatures at the 3,216-metre summit of Greenland’s ice sheet surpassed freezing point, peaking at 0.48℃. Rain fell on the summit for several hours that morning and on August 15.

This was particularly shocking given the above-freezing temperatures occurred so late in Greenland’s normally short summer. At this time of year, large areas of bare ice are exposed from a lack of snow, which leads to greater runoff of rainwater and meltwater into the oceans.

Temperatures rarely surpass freezing at Greenland’s highest point.
Shutterstock

When melting is self-reinforcing

Rainfall makes the ice sheet more prone to surface melt since it exacerbates the so-called “ice-albedo positive feedback”. In other words, the melting reinforces itself.

When rain falls, its warmth can melt snow, exposing the underlying darker ice, which absorbs more sunlight. This increases temperatures at the surface, leading to more melting.

Unfortunately, this isn’t the only positive feedback loop destabilising the Greenland ice sheet.

The “positive melt-elevation feedback” is another, where the lower height of the ice sheet leads to faster melting because higher temperatures occur at lower altitudes.

Also worrying is when higher temperatures cause coastal glaciers to thin, allowing more ice to slip into the sea. This both speeds up the rate of glacier flow towards the sea and lowers the ice surface, exposing it to warmer air temperatures and, in turn, increasing melting.

The rate of ice loss in both Greenland and Antarctica is accelerating.
Shutterstock

What does this mean for the planet?

These positive feedbacks can lead to tipping points — abrupt and irreversible changes in the climate system after a certain threshold is reached. We are more likely to reach these tipping points as emissions increase and global temperatures rise.

While the science on tipping points is still emerging, the most recent report from the Intergovernmental Panel on Climate Change said they cannot be ruled out. The report identified likely tipping points such as widespread Arctic sea-ice melting and the thawing of methane-rich permafrost.

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Read more:
‘Failure is not an option’: after a lost decade on climate action, the 2020s offer one last chance

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Recent studies show what humanity may be up against. A study from May this year showed a substantial part of the Greenland ice sheet is either at, or about to reach, a tipping point where melting will accelerate, even if global warming is stopped. Scientists are concerned reaching this point may trigger a cascade effect, leading to other tipping points being reached.

Melted ice from both the Arctic Ocean and Greenland have caused an influx of freshwater into the North Atlantic Ocean. This has contributed to the slowing of a system of crucial ocean currents, which carry warm water from the tropics into the colder North Atlantic. This current, called the Atlantic Meridional Overturning Circulation (AMOC), has slowed by 15% since the 1950s.

If the AMOC slows down any further, the consequences for the planet could be profound. It could destabilise the West African monsoon, cause more frequent drought in the Amazon rainforest and accelerate ice loss in Antarctica.

An existential threat

The rising likelihood of tipping points being reached beyond 1.5℃ of warming represents a potential, looming existential threat to human civilisation. However, even if we’ve already crossed some tipping points, as some scientists suggest, how fast the impacts unfold is still within our control.

If we limit global warming to 1.5℃ this century, we give ourselves longer to adapt to heating already locked into the Earth’s system. But the window is rapidly closing; estimates indicate we may reach the crucial 1.5℃ threshold as soon as the mid-2030s.

The message for humanity is urgent: hard science, not cloying political spin, needs to dictate climate action in the coming years. As with COVID-19, listening to the scientists gives us the best hope of saving the planet.

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Read more:
When Greenland was green: rapid global warming 55 million years ago shows us what the future may hold

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Willow Hallgren, Adjunct Research Fellow, Centre for Planetary Health and Food Security, Griffith University

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

Pacific Island bats are utterly fascinating, yet under threat and overlooked. Meet 4 species

Artwork by Arison Kul from Lae Papua New Guinea.

John Martin, University of Sydney; David L. Waldien, Christopher Newport University; Junior Novera, The University of Queensland; Justin A. Welbergen, Western Sydney University; Malik OEDIN, Université de Nouvelle Calédonie; Nicola Hanrahan, Charles Darwin University; Tigga Kingston, Texas Tech University, and Tyrone Lavery, Australian National UniversityAm I not pretty enough? This article is part of The Conversation’s new series introducing you to unloved animals that need our help.

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A whopping 191 different bat species live in the Pacific Islands across Micronesia, Melanesia, and Polynesia — but these are, collectively, the most imperilled in the world. In fact, five of the nine bat species that have gone extinct in the last 160 years have come from this region.

For too long, the conservation of Pacific Island bats has been largely overlooked in science. Of the 191 existing species, 25% are threatened with extinction, and we lack information to assess the status of a further 15%.

Just as these bats are rare and far-flung across the Pacific islands, so is the expertise and research needed to conserve them along with the vital ecosystem services they provide, such as pollination, seed dispersal, and insect control.

The first-ever Pacific Islands Bat Forum, held earlier this month, sought to change this, bringing together a new network of researchers, conservationists, and community members — 380 people from 40 countries and territories — dedicated to their survival.

So, why should we care about these bats anyway?

Conserving Pacific Island bats is paramount for preserving the region’s diverse human cultures and for safeguarding the healthy functioning of island ecosystems.

In many Pacific Island nations, bats have great cultural significance as totems, food, and traditional currency.

Bats are the largest land animals on many of the Pacific islands, and are vital “keystone species”, maintaining the structure of ecological communities.

Yet, Pacific Island bats are increasingly under threat, including from intensifying land use (farming, housing, roads) invasive species (rats, cats, snakes, ants), and human harvesting. They’re also vulnerable to climate change, which heightens sea levels and increases the intensity of cyclones and heatwaves.

So let’s meet four fascinating — but threatened — Pacific Island bats that deserve more attention.

1. Pacific sheath-tailed bat

Conservation status: endangered

Distribution: American Samoa, Federated States of Micronesia, Fiji, Guam, Northern Mariana Islands, Palau, Samoa, Tonga

Pacific Sheath tailed Bat (Emballonura semicaudata)
Ron Leidich

The Pacific sheath-tailed bat (Emballonura semicaudata) weighs just five-grams and has a weak, fluttering flight. Yet somehow, it has colonised some of the smaller and more isolated islands across the Pacific, from Samoa to Palau. That’s across 6,000 kilometres of ocean!

Over the past decade, this insect-eating, cave-roosting bat has disappeared from around 50% of islands where it has been recorded. The reasons for this are unclear. Disturbance of cave roosts, introduced species such as lantana and goats, and increasing use of pesticides, may all have played a part.

Unfortunately, the Pacific sheath-tailed bat is now presumed extinct in many former parts of its range, including American Samoa, Tonga, and several islands of the Northern Mariana Islands. This leaves Palau, the Federated States of Micronesia, and Fiji as remaining strongholds for the species, though data is limited.

2. Montane monkey-faced bat

Conservation status: critically endangered

Distribution: Solomon Islands

New Georgian monkey-faced bat Pteralopex taki — no picture exists of the Montane monkey-faced bat.
Tyrone Lavery

There are six species of monkey-faced bat — all are threatened, and all are limited to islands across the Solomon Islands, Bougainville, and Fiji.

The montane monkey-faced bat (Pteralopex pulchra) is one species, and weighs around 280 grams, eats fruit and nectar, and has incredibly robust teeth. But perhaps most startling is its ruby-red eyes and wing membranes that are marbled with white and black.

The montane monkey-faced bat has been recorded only once by scientists on a single mountain (Mt Makarakomburu) above the altitude of 1,250 metres, on Guadalcanal Island. This tiny range makes it vulnerable to rare, extreme events such as cyclones, which could wipe out a whole population in one swoop. And being limited to mountain-top cloud forests could place it at greater risk from climate change.

It’s an extreme example of both the endemism (species living in a small, defined area) and inadequacies of scientific knowledge that challenge Pacific island bat conservation.

3. Ornate flying-fox

Conservation status: vulnerable

Distribution: New Caledonia

Ornate flying-fox (Pteropus ornatus)‘
Malik Oedin, IAC

Like many fruit bats across the Pacific, New Caledonia’s endemic ornate flying-fox (Pteropus ornatus) is an emblematic species. Flying-foxes are hunted for bush meat, used as part of cultural practices by the Kanaks (Melanesian first settlers), are totems for some clans, and feature as a side dish during the “New Yam celebration” each year. Their bones and hair are also used to make traditional money.

Because they’re so highly prized, flying-foxes can be subject to illegal trafficking. Despite the Northern and Southern Provinces of New Caledonia having regulated hunting, flying-fox populations continue to decline. Recent studies predict 80% of the population will be gone in the next 30 years if hunting continues at current levels.

On a positive note, earlier this year the Northern Province launched a conservation management program to protect flying-fox populations while incorporating cultural values and practices.

4. Fijian free-tailed bat

Conservation status: endangered

Distribution: Fiji, Vanuatu

Fijian free tailed bat (Chaerophon bregullae)
Dave Waldien

In many ways, the Fijian free-tailed bat (Chaerephon bregullae) has become the face of proactive bat conservation in the Pacific Islands. This insect-eating bat requires caves to roost during the day and is threatened when these caves are disturbed by humans as it interrupts their daytime roosting. The loss of foraging habitat is another major threat.

The only known colony of reproducing females lives in Nakanacagi Cave in Fiji, with around 7,000 bats. In 2014, an international consortium with Fijian conservationists and community members came together to protect Nakanacagi Cave. As a result, it became recognised as a protected area in 2018.

But this species shares many characteristics with three of the nine bat species that have gone extinct globally. This includes being a habitat specialist, its unknown cause of decline, and its potential exposure to chemicals through insect foraging. It’s important we continue to pay close attention to its well-being.

Where do we go from here?

The perspectives of local knowledge from individual islands aren’t always captured in global scientific assessments of wildlife.

In many Pacific Islands, bats aren’t protected by national laws. Instead, in many countries, most land is under customary ownership, which means it’s owned by Indigenous peoples. This includes land in Papua New Guinea, Solomon Islands, and Vanuatu. Consequently, community landowners have the power to enact their own conservation actions.

The emerging Pacific Bat Network, inspired by the recent forum, aims to foster collaborative relationships between scientific conservationists and local leaders for species protection, while respecting cultural practices.

As the Baru Conservation Alliance — a locally-led, not-for-profit group from Malaita, Solomon Islands — put it in their talk at the forum:

conservation is not a new thing for Kwaio.

Now the forum has ended, the diverse network of people passionate about bat conservation is primed to work together to strengthen the conservation of these unique and treasured bats of the Pacific.

John Martin, Research Scientist, Taronga Conservation Society Australia & Adjunct lecturer, University of Sydney; David L. Waldien, Adjunct assistant professor, Christopher Newport University; Junior Novera, PhD Candidate, School of Biological Sciences, The University of Queensland; Justin A. Welbergen, President of the Australasian Bat Society | Associate Professor of Animal Ecology, Western Sydney University; Malik OEDIN, PhD Population Biology and Ecology, Université de Nouvelle Calédonie; Nicola Hanrahan, Terrestrial Ecologist, Department of Environment, Parks and Water Security, Northern Territory Government & Visiting Fellow, Charles Darwin University; Tigga Kingston, Professor, Department of Biological Sciences, Texas Tech University, and Tyrone Lavery, Postdoctoral Research Fellow, Australian National University

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