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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Climate change is causing tuna to migrate, which could spell catastrophe for the small islands that depend on them

Katherine Seto, University of Wollongong; Johann Bell, University of Wollongong; Quentin Hanich, University of Wollongong, and Simon Nicol, University of CanberraSmall Pacific Island states depend on their commercial fisheries for food supplies and economic health. But our new research shows climate change will dramatically alter tuna stocks in the tropical Pacific, with potentially severe consequences for the people who depend on them.

As climate change warms the waters of the Pacific, some tuna will be forced to migrate to the open ocean of the high seas, away from the jurisdiction of any country. The changes will affect three key tuna species: skipjack, yellowfin, and bigeye.

Pacific Island nations such as the Cook Islands and territories such as Tokelau charge foreign fishing operators to access their waters, and heavily depend on this revenue. Our research estimates the movement of tuna stocks will cause a fall in annual government revenue to some of these small island states of up to 17%.

This loss will hurt these developing economies, which need fisheries revenue to maintain essential services such as hospitals, roads and schools. The experience of Pacific Island states also bodes poorly for global climate justice more broadly.

Island states at risk

Catches from the Western and Central Pacific represent over half of all tuna produced globally. Much of this catch is taken from the waters of ten small developing island states, which are disproportionately dependent on tuna stocks for food security and economic development.

These states comprise:

• Cook Islands
• Federated States of Micronesia
• Kiribati
• Marshall Islands
• Nauru
• Palau
• Papua New Guinea
• Solomon Islands
• Tokelau
• Tuvalu

Their governments charge tuna fishing access fees to distant nations of between US$7.1 million (A$9.7 million) and $134 million (A$182 million), providing an average of 37% of total government revenue (ranging from 4-84%).

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Tuna stocks are critical for these states’ current and future economic development, and have been sustainably managed by a cooperative agreement for decades. However, our analysis reveals this revenue, and other important benefits fisheries provide, are at risk.

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Climate change and migration

Tuna species are highly migratory – they move over large distances according to ocean conditions. The skipjack, yellowfin and bigeye tuna species are found largely within Pacific Island waters.

Concentrations of these stocks normally shift from year to year between areas further to the west in El Niño years, and those further east in La Niña years. However, under climate change, these stocks are projected to shift eastward – out of sovereign waters and into the high seas.

Under climate change, the tropical waters of the Pacific Ocean will warm further. This warming will result in a large eastward shift in the location of the edge of the Western Pacific Warm Pool (a mass of water in the western Pacific Ocean with consistently high water temperatures) and subsequently the prime fishing grounds for some tropical tuna.

This shift into areas beyond national jurisdiction would result in weaker regulation and monitoring, with parallel implications for the long-term sustainability of stocks.

Pacific Tuna: Feeling the Heat.

What our research found

Combining climate science, ecological models and economic data from the region, our research published today in Nature Sustainability shows that under strong projections of climate change, small island economies are poised to lose up to US$140 million annually by 2050, and up to 17% of annual government revenue in the case of some states.

The Intergovernmental Panel on Climate Change (IPCC) provides scenarios of various greenhouse gas concentrations, called “representative concentration pathways” (RCP). We used a higher RCP of 8.5 and a more moderate RCP of 4.5 to understand tuna movement in different emissions scenarios.

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In the RCP 8.5 scenario, by 2050, our model predicted the total biomass of the three species of tuna in the combined jurisdictions of the ten Pacific Island states would decrease by an average of 13%, and up to 20%.

But if emissions were kept to the lower RCP 4.5 scenario, the effects are expected to be far less pronounced, with an average decrease in biomass of just 1%.

While both climate scenarios result in average losses of both tuna catches and revenue, lower emissions scenarios lead to drastically smaller losses, highlighting the importance of climate action.

These projected losses compound the existing climate vulnerability of many Pacific Island people, who will endure some of the earliest and harshest climate realities, while being responsible for only a tiny fraction of global emissions.

Fishing access fees make up a large proportion of government revenue for these Pacific Island nations.
Shutterstock

What can be done?

Capping greenhouse gas emissions, and reducing them to levels aligning with the Paris Agreement, would reduce multiple climate impacts for these states, including shifting tuna stocks.

In many parts of the world, the consequences of climate change compound upon one another to create complex injustices. Our study identifies new direct and indirect implications of climate change for some of the world’s most vulnerable populations.

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Katherine Seto, Research Fellow, University of Wollongong; Johann Bell, Visiting Professorial Fellow, University of Wollongong; Quentin Hanich, Associate Professor, University of Wollongong, and Simon Nicol, Adjunct professor, University of Canberra

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

Monarch butterflies’ spectacular migration is at risk – an ambitious new plan aims to help save it

Monarch butterflies cover a tree at El Rosario Monarch Butterfly Sanctuary in Michoacán, Mexico.
D. André Green II, CC BY-ND

D. André Green II, University of Michigan

One of nature’s epic events is underway: Monarch butterflies’ fall migration. Departing from all across the United States and Canada, the butterflies travel up to 2,500 miles to cluster at the same locations in Mexico or along the Pacific Coast where their great-grandparents spent the previous winter.

Human activities have an outsized impact on monarchs’ ability to migrate yearly to these specific sites. Development, agriculture and logging have reduced monarch habitat. Climate change, drought and pesticide use also reduce the number of butterflies that complete the journey.

Monarch butterflies migrate south in fall and north in spring, traveling up to 2,500 miles.
MonarchWatch.org, CC BY-ND

Since 1993, the area of forest covered by monarchs at their overwintering sites in Mexico has fallen from a peak of 45 acres in 1996-1997 to as low as 1.66 acres in the winter of 2013-2014. A 2016 study warned that monarchs were dangerously close to a predicted “point of no return.” The 2019 count of monarchs in California was the lowest ever recorded for that group.

What was largely a bottom-up, citizen-powered effort to save the struggling monarch butterfly migration has shifted toward a top-down conversation between the federal government, private industry and large-tract landowners. As a biologist studying monarchs to understand the molecular and genetic aspects of migration, I believe this experiment has high stakes for monarchs and other imperiled species.

Millions of people care about monarchs

I will never forget the sights and sounds the first time I visited monarchs’ overwintering sites in Mexico. Our guide pointed in the distance to what looked like hanging branches covered with dead leaves. But then I saw the leaves flash orange every so often, revealing what were actually thousands of tightly packed butterflies. The monarchs made their most striking sounds in the Sun, when they burst from the trees in massive fluttering plumes or landed on the ground in the tussle of mating.

Decades of educational outreach by teachers, researchers and hobbyists has cultivated a generation of monarch admirers who want to help preserve this phenomenon. This global network has helped restore not only monarchs’ summer breeding habitat by planting milkweed, but also general pollinator habitat by planting nectaring flowers across North America.

A monarch butterfly in a Toronto park on common milkweed, an important plant for its survival.
Colin McConnell/Toronto Star via Getty Images

Scientists have calculated that restoring the monarch population to a stable level of about 120 million butterflies will require planting 1.6 billion new milkweed stems. And they need them fast. This is too large a target to achieve through grassroots efforts alone. A new plan, announced in the spring of 2020, is designed to help fill the gap.

Pros and cons of regulation

The top-down strategy for saving monarchs gained energy in 2014, when the U.S. Fish and Wildlife Service proposed listing them as threatened under the Endangered Species Act. A decision is expected in December 2020.

Listing a species as endangered or threatened triggers restrictions on “taking” (hunting, collecting or killing), transporting or selling it, and on activities that negatively affect its habitat. Listing monarchs would impose restrictions on landowners in areas where monarchs are found, over vast swaths of land in the U.S.

In my opinion, this is not a reason to avoid a listing. However, a “threatened” listing might inadvertently threaten one of the best conservation tools that we have: public education.

It would severely restrict common practices, such as rearing monarchs in classrooms and back yards, as well as scientific research. Anyone who wants to take monarchs and milkweed for these purposes would have to apply for special permits. But these efforts have had a multigenerational educational impact, and they should be protected. Few public campaigns have been more successful at raising awareness of conservation issues.

University of Michigan biologist D. Andre Green studies monarch butterflies’ DNA to understand what drives their incredible migration.

The rescue attempt

To preempt the need for this kind of regulation, the U.S. Fish and Wildlife Service approved a Nationwide Candidate Conservation Agreement for Monarch Butterflies. Under this plan, “rights-of-way” landowners – energy and transportation companies and private owners – commit to restoring and creating millions of acres of pollinator habitat that have been decimated by land development and herbicide use in the past half-century.

The agreement was spearheaded by the Rights-of-Way Habitat Working Group, a collaboration between the University of Illinois Chicago’s Energy Resources Center, the Fish and Wildlife Service and over 40 organizations from the energy and transportation sectors. These sectors control “rights-of-way” corridors such as lands near power lines, oil pipelines, railroad tracks and interstates, all valuable to monarch habitat restoration.

Under the plan, partners voluntarily agree to commit a percentage of their land to host protected monarch habitat. In exchange, general operations on their land that might directly harm monarchs or destroy milkweed will not be subject to the enhanced regulation of the Endangered Species Act – protection that would last for 25 years if monarchs are listed as threatened. The agreement is expected to create up to 2.3 million acres of new protected habitat, which ideally would avoid the need for a “threatened” listing.

Many questions remain. Scientists are still learning about factors that cause monarch population decline, so it is likely that land management goals will need to change over the course of the agreement, and partner organizations will have to adjust to those changes.

Oversight of the plan will fall primarily to the University of Illinois, and ultimately to the U.S. Fish & Wildlife Service. But it’s not clear whether they will have the resources they need. And without effective oversight, the plan could allow parties to carry out destructive land management practices that would otherwise be barred under an Endangered Species Act listing.

A model for collaboration

This agreement could be one of the few specific interventions that is big enough to allow researchers to quantify its impact on the size of the monarch population. Even if the agreement produces only 20% of its 2.3 million acre goal, this would still yield nearly half a million acres of new protected habitat. This would provide a powerful test of the role of declining breeding and nectaring habitat compared to other challenges to monarchs, such as climate change or pollution.

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Scientists hope that data from this agreement will be made publicly available, like projects in the Monarch Conservation Database, which has tracked smaller on-the-ground conservation efforts since 2014. With this information we can continue to develop powerful new models with better accuracy for determining how different habitat factors, such as the number of milkweed stems or nectaring flowers on a landscape scale, affect the monarch population.

North America’s monarch butterfly migration is one of the most awe-inspiring feats in the natural world. If this rescue plan succeeds, it could become a model for bridging different interests to achieve a common conservation goal.

D. André Green II, Assistant Professor of Ecology and Evolutionary Biology, University of Michigan

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).

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.

Ocean warming has fisheries on the move, helping some but hurting more

An Atlantic cod on ice. Cod fisheries in the North Sea and Irish Sea are declining due to overfishing and climate change.
Robert F. Bukaty/AP

Chris Free, University of California, Santa Barbara

Climate change has been steadily warming the ocean, which absorbs most of the heat trapped by greenhouse gases in the atmosphere, for 100 years. This warming is altering marine ecosystems and having a direct impact on fish populations. About half of the world’s population relies on fish as a vital source of protein, and the fishing industry employs more the 56 million people worldwide.

My recent study with colleagues from Rutgers University and the U.S. National Oceanic and Atmospheric Administration found that ocean warming has already impacted global fish populations. We found that some populations benefited from warming, but more of them suffered.

Overall, ocean warming reduced catch potential – the greatest amount of fish that can be caught year after year – by a net 4% over the past 80 years. In some regions, the effects of warming have been much larger. The North Sea, which has large commercial fisheries, and the seas of East Asia, which support some of the fastest-growing human populations, experienced losses of 15% to 35%.

The reddish and brown circles represent fish populations whose maximum sustainable yields have dropped as the ocean has warmed. The darkest tones represent extremes of 35 percent. Blueish colors represent fish yields that increased in warmer waters.
Chris Free, CC BY-ND

Although ocean warming has already challenged the ability of ocean fisheries to provide food and income, swift reductions in greenhouse gas emissions and reforms to fisheries management could lessen many of the negative impacts of continued warming.

How and why does ocean warming affect fish?

My collaborators and I like to say that fish are like Goldilocks: They don’t want their water too hot or too cold, but just right.

Put another way, most fish species have evolved narrow temperature tolerances. Supporting the cellular machinery necessary to tolerate wider temperatures demands a lot of energy. This evolutionary strategy saves energy when temperatures are “just right,” but it becomes a problem when fish find themselves in warming water. As their bodies begin to fail, they must divert energy from searching for food or avoiding predators to maintaining basic bodily functions and searching for cooler waters.

Thus, as the oceans warm, fish move to track their preferred temperatures. Most fish are moving poleward or into deeper waters. For some species, warming expands their ranges. In other cases it contracts their ranges by reducing the amount of ocean they can thermally tolerate. These shifts change where fish go, their abundance and their catch potential.

Warming can also modify the availability of key prey species. For example, if warming causes zooplankton – small invertebrates at the bottom of the ocean food web – to bloom early, they may not be available when juvenile fish need them most. Alternatively, warming can sometimes enhance the strength of zooplankton blooms, thereby increasing the productivity of juvenile fish.

Understanding how the complex impacts of warming on fish populations balance out is crucial for projecting how climate change could affect the ocean’s potential to provide food and income for people.

Warming is affecting virtually all regions of the ocean.

Impacts of historical warming on marine fisheries

Sustainable fisheries are like healthy bank accounts. If people live off the interest and don’t overly deplete the principal, both people and the bank thrive. If a fish population is overfished, the population’s “principal” shrinks too much to generate high long-term yields.

Similarly, stresses on fish populations from environmental change can reduce population growth rates, much as an interest rate reduction reduces the growth rate of savings in a bank account.

In our study we combined maps of historical ocean temperatures with estimates of historical fish abundance and exploitation. This allowed us to assess how warming has affected those interest rates and returns from the global fisheries bank account.

Losers outweigh winners

We found that warming has damaged some fisheries and benefited others. The losers outweighed the winners, resulting in a net 4% decline in sustainable catch potential over the last 80 years. This represents a cumulative loss of 1.4 million metric tons previously available for food and income.

Some regions have been hit especially hard. The North Sea, with large commercial fisheries for species like Atlantic cod, haddock and herring, has experienced a 35% loss in sustainable catch potential since 1930. The waters of East Asia, neighbored by some of the fastest-growing human populations in the world, saw losses of 8% to 35% across three seas.

Other species and regions benefited from warming. Black sea bass, a popular species among recreational anglers on the U.S. East Coast, expanded its range and catch potential as waters previously too cool for it warmed. In the Baltic Sea, juvenile herring and sprat – another small herring-like fish – have more food available to them in warm years than in cool years, and have also benefited from warming. However, these climate winners can tolerate only so much warming, and may see declines as temperatures continue to rise.

Shucking scallops in Maine, where fishery management has kept scallop numbers sustainable.
Robert F. Bukaty/AP

Management boosts fishes’ resilience

Our work suggests three encouraging pieces of news for fish populations.

First, well-managed fisheries, such as Atlantic scallops on the U.S. East Coast, were among the most resilient to warming. Others with a history of overfishing, such as Atlantic cod in the Irish and North seas, were among the most vulnerable. These findings suggest that preventing overfishing and rebuilding overfished populations will enhance resilience and maximize long-term food and income potential.

Second, new research suggests that swift climate-adaptive management reforms can make it possible for fish to feed humans and generate income into the future. This will require scientific agencies to work with the fishing industry on new methods for assessing fish populations’ health, set catch limits that account for the effects of climate change and establish new international institutions to ensure that management remains strong as fish migrate poleward from one nation’s waters into another’s. These agencies would be similar to multinational organizations that manage tuna, swordfish and marlin today.

Finally, nations will have to aggressively curb greenhouse gas emissions. Even the best fishery management reforms will be unable to compensate for the 4 degree Celsius ocean temperature increase that scientists project will occur by the end of this century if greenhouse gas emissions are not reduced.

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Chris Free, Postdoctoral Scholar, University of California, Santa Barbara

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

How barnacle geese adjust their migratory habits in the face of climate change

Shutterstock

Thomas Oudman, University of St Andrews

The climate is changing at an unprecedented rate, and so are the environments of many plant and animal species. Populations die out in places that become intolerable, and thrive in other places that have become more benign.

But for many species, population growth in new places does not keep up with the decline elsewhere. For some species, such as polar bears, such benign places do not even exist. And even if they do, species still face a significant problem: they need to find them.

This problem is perhaps more serious for migratory animals, which have to adjust to not one, but several changing environments that they visit throughout the year. Even after finding a new habitat one year, they must find it again the next, and every year after that. How on earth do these creatures know where to go?

This question is not trivial: many migratory populations are declining. What seems to be killing them is their inability to adjust to multiple changing habitats at once. The problem might be that it is hard for them to learn new migratory habits.

Geese lead the way

But a few migratory species are thriving. Among them are barnacle geese, a small-sized goose that winters in Europe and traditionally breeds on the Arctic tundras of Siberia, Svalbard and Greenland. So, how are they doing so well?

The barnacle goose faced extinction in the 1950s.
Shutterstock

We barely know the exact routes of many migratory species, let alone how these have changed over time. But here, barnacle geese are the exception. Ever since their near extinction in the 1950s, when fewer than 500 geese were left, scientists have been monitoring their numbers. The geese were observed in their wintering area at the Solway Firth, between Scotland and England, all along the Norwegian coast during spring migration and up to Svalbard.

Each spring from the 1970s onwards, researchers went to Helgeland on Norway’s west coast to observe the geese arriving from the UK to fill their bellies on grass. These fat reserves are essential to complete the second part of their journey north to Svalbard, where they breed.

In the early 1990s, bird researchers discovered a handful of barnacle geese in Vesterålen, 350km to the north-west of Helgeland, while they were counting pink-footed geese – another vulnerable goose population. Since then, the number of barnacle geese in Vesterålen in spring has been increasing steadily.

From the 2000s onwards, goose observers at the traditional feeding site in Helgeland started to see numbers go down. Currently, the majority of the whole population (now 40,000 birds strong) stops off in Vesterålen.

Rapid adjustments? Certainly. The number of geese in Vesterålen in spring has actually grown faster than can be explained by the birth rate alone, meaning that what we’re seeing is not just “the survival of the fittest”. In addition, many individual geese must have switched to feeding in Vesterålen later in life.

Barnacle geese calling.
Juha Saari/Xeno-Canto, CC BY-SA1.4 MB (download)

Along with counting geese, international research groups have been catching geese in the breeding areas on Svalbard since the 1960s, fitting juvenile geese with plastic leg rings with letter codes. This allowed goose observers along the Norwegian coast to actually know which bird they were looking at, and even how old it was.

Since 2000, these observers have gathered enough observations of ringed barnacle geese each year to allow proper calculations. This has enabled us to show that geese are indeed switching to Vesterålen in big numbers. In addition, the probability for individual geese to move to Vesterålen has been increasing, and young birds are far more likely to switch than older ones.

Adapting to climate change

So are these changes a response to climate change? We analysed the grass growth during the feeding period at both locations, which we could estimate from daily temperature and sunshine levels. The start of grass growth in spring has advanced more than three weeks since the 1970s, leading to a strong increase in grass availability during the goose staging period in spring at both locations. But availability is not all that counts.

Barnacle geese arrive in Norway at the end of April. In the 1970s, the snow usually had just melted at that time, and the first grass shoots were coming up. In recent years, the grass was already long when the geese arrived, and contained more cellulose. This is much more difficult for geese to digest than young grass, resulting in a lower rate of fat storage.

Vesterålen is further north, and spring starts much later than in Helgeland. This means that due to climate warming, the annual timing of grass growth in Vesterålen now is how it used to be in Helgeland. Fresh new grass now is just emerging in Vesterålen when the geese arrive, enabling the geese to gain weight fast. So yes, the switch makes sense.

Does that mean that the geese know that the new place is better? Not necessarily. Most of the switchers are young birds, which do not have much experience. Instead, we think that they follow experienced birds to Vesterålen, perhaps after they have arrived in Helgeland to find there is not enough food to go around. Geese operate in families, staying close to their long-term partners and relatives. They might exchange more information than we know.

It’s the group travelling that does the trick for geese, allowing them to profit from the discoveries of others. The question that remains is why other bird species have not evolved in the same way. Perhaps geese have always lived in a more dynamic environment than other migratory species.

Think of shorebirds, which have been dependent on the same shorelines and inter-tidal areas for thousands of years. For them, the current rate of climate change might be something they have not evolved to deal with. Perhaps we are creating a world in which all birds would be better off acting like geese.

Thomas Oudman, Postdoctoral Researcher, School of Biology, University of St Andrews

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

Africa’s Wildebeest Migration

Cross-pollination, migration, adaptation: Australia’s fragile grasslands at the Venice Biennale

Ten thousand native grassland plants were grown in Italy for Australia’s national pavilion at the Biennale.
Dane Voorderhake

William Feuerman, University of Technology Sydney

Review: Venice Biennale (Architecture)

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The 16th International Architecture Exhibition, the Venice Biennale, is now open. With 62 countries represented, the Biennale is a demonstration of “how the world might be perceived differently from diverse parts of our planet,” as described by the event curators.

This year’s theme, Freespace, is about the potential of architecture to be perceived beyond face value. With a somewhat romantic undertone, the curatorial statement emphasises the physical building. This is in clear contrast to the 15th Biennale in 2016, curated by Chilean architect Alejandro Aravena, which foregrounded social and political issues.

There are 62 national pavilions mostly in or around the Giardini, Venice’s parkland. The pavilions, with curators selected from each respective country, provide great insight into the current state of the architecture profession.

Repair, Australia’s Pavilion, curated by Baracco+Wright Architects in collaboration with artist Linda Tegg, constructs an immersive sensory experience for visitors. Repair aims to reclaim endangered grasslands that existed pre-European settlement.
More than 10,000 plants, including 65 different Victorian grassland species, fill a black cube designed by Denton Corker Marshall architects.

Only 1% of these grasslands remain in Victoria. The Australian curators explained that the reclamation of grasslands is “a sort of reverse order of urban sprawl”.

Projections in Australia’s national pavilion show other buildings that have incorporated nature.
Dane Voorderhake

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Read more:
EcoCheck: Victoria’s flower-strewn western plains could be swamped by development

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The plants are arranged in sporadic densities throughout the space. I yearned for the room to be filled even more as the smells, which are ever present, brought a familiarity to a foreign place. Artificial lights above illuminate and protect the interior landscape. Every so often the lights dim and two perpendicular walls project videos of 15 Australian architecture projects that address the environmental issues posed by the curators.

At face value, the pavilion can be seen purely as a comment on the environment, but more important is the process the curators took to construct the exhibition. The 10,000 Australian plants were “lovingly nurtured from seedlings to maturity in Sanremo, Italy”.

Like Australian gum trees that have made their home in California, these Victorian grasslands in Venice represent a successful model of migration and adaptation, just as the ritual of this Biennale represents at best, moments of productive displacement and cross-pollination.

Switzerland’s national pavilion, winner of the Biennale’s Golden Lion.
Dane Voorderhake

Still, the grasslands pavilion left open the question of what would happen to these exiles after the Biennale. Would they be returned home, and at what cost? In our era of mass migration and high carbon footprint transport and agriculture, I wondered what fate would be most fitting.

This year’s Golden Lion Winner, the top award at the Biennale, was awarded to Switzerland for House Tour. In perfect Swiss style, the exhibition creates domestic spaces at multiple scales using materials and fittings commonly used in new-build housing or rented apartments. Curated by Alessandro Bosshard, Li Tavor, Matthew van der Ploeg and Ani Vihervaara, the exhibition aims to question the acceptance of banality.

The British Pavilion, Island, constructs a scaffold around an existing building, providing access to the upper roof structure where the 1909 building pokes out at the centre of the terrace, a literal island. Inside, the pavilion remains empty, void of an exhibition. As the British curators, Adam Caruso, Peter St John and Marcus Taylor, describe

The state of the building suggests many themes; including abandonment, reconstruction, sanctuary, Brexit, isolation, colonialism and climate change. It is intended as a platform, in this case also literally, for a new and optimistic beginning.

The British pavilion constructed a scaffold around an existing building.
Dane Voorderhake

At the entry to the Arsenale, the centrepiece of the Biennale located in a 13th century Venetian shipyard, curators Yvonne Farrell and Shelley McNamara have hung what feels like hundreds of strands of rope. Here begins the showcase of 71 architects from around the world, each responding to the event’s theme.

The space is filled with a beautiful, yet erratic, set of architectural models, full-scale constructions and interactive media. The Central Pavilion, the Biennale’s other major venue, has a similar sprinkling of work.

The entrance of the Arsenale at the Venice Biennale.
Dane Voorderhake

The 71 participants have each built an object of delight, transforming the 200m hall into a street scene with a series of micro buildings along its sides.

Australian architect John Wardle’s popular installation, Somewhere Other, is an optical machine, or as the placard describes, “a portal, an elaborate window, a calibrated device, a long lens between Venice and Australia”. Australia is also represented by Tasmanian architects Room 11.

Somewhere Else designed by John Wardle.
Dane Voorderhake

Somewhere Other is a beautifully made native timber object generating a range of experiences for its users. It is poetic in both description and construction, a striking demonstration of Wardle’s work and a strong representation of a continent about as far from Venice as you can get.

Other highlights include the a model of the Fuji kindergarten designed by Japanese firm Tezuka Architects. Projected drone footage shows children running free around the school’s circular roof.

Tezuka Architects’ kindergarten with projections of children.
Dane Voorderhake

Ricccardo Blummer and team’s Automatiche E Altri Esercizi (Italy), is “a walkable machine that continually builds minimal surfaces, composed of water and soap which only the reflection of light makes visible”.

Other projects to note were PROP/GLOBAL’s (Portugal) interactive media projected onto a curtain of fine grain tassels that form an enclosure; Valero Olgiati’s (Switzerland) intervention of 33 white slender cylindrical columns producing what he describes as “an intensified spatial experience”; and Kazuya Sejima and Ryue Nishizawa’s (Japan) acrylic, almost invisible, layered circular space.

Despite the beauty and poetry of many of the works aligning the Arsenale, one cannot deny their indulgence. In 2016, curator Alejandro Aravena asked if exhibitions would widen their scope beyond cultural and artistic dimensions to social, political, economic and environmental ideas. It’s not clear to me that many of the exhibitors at the current Biennale have done this.

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The Venice Biennale is on until November 25 2018.

William Feuerman, Senior Lecturer, School of Architecture, University of Technology Sydney

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

Africa’s great migrations are failing but there is a solution – and you can eat it too

A Wildebeeste, or Gnu.
Wikimedia Commons

Penny van Oosterzee, James Cook University

Until I went to southern Africa last year, I couldn’t imagine an African savanna without its awe-inspiring migrations. But Africa’s plains are increasingly empty of wildlife. My subsequent investigation showed that fences are marching across the savannas instead.

An audit of 24 large mammal species, which used to migrate regularly, showed that many migrations are already extinct. Fences stopped animals in their tracks, often within sight of the food and water that would sustain them. These fences had severed historically massive migrations. Millions of wild animals – wildebeest, zebra, hartebeest, springbok and many others – have likely died of thirst or hunger since the 1950s.

It’s a huge problem, yet it has received little attention. In Kenya, fences form clusters and virtual battle lines, threatening the collapse of the entire Greater-Mara ecosystem. A recent global study of 57 species of moving mammals shows that the future of the planet’s most spectacular natural events is on the cusp.

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Read more:
Why smart agricultural development is needed in Africa’s savannas

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A land divided

Botswana is one of the last great places on earth for free-ranging wildlife. Here, fences erected to protect European beef producers from foot-and-mouth disease (FMD) slice the country into 17 “islands”.

Fencing is expensive – especially fencing strong enough to keep out migrating animals – and it favours only a small proportion of cattle owners, locking local livestock farmers out of the export industry. To make matters worse, this comes as wildlife-based tourism is overtaking livestock as a proportion of GDP in countries like Botswana.

An elephant, behind one of the high double layered veterinary fences used in Botswana.
M. Atkinson

With colonial-era subsidies of the fencing system gone, what’s left is a lose-lose system that hinders local farmers, tourism and sustainability. Many savanna landscapes are now conflict zones between local people and wildlife.

Against this bleak backdrop, a rare good news story has emerged, driven by myth-busting science and patient advocacy. It turns out that wildlife does not play a significant role in the transmission foot-and-mouth disease, apart from the African buffalo; ironically it is more likely to be spread by cattle. Many areas, like the Kalahari, have no cattle or buffalo – so the fences in those areas serve no disease control purpose.

Careful scientific sleuthing is showing that migrations restart when these fences are removed. The longest animal migration ever recorded, of zebras across Botswana, resumed a few years ago after just a portion of fence was removed.

Process over place

Perhaps the most important breakthrough has been a relatively new scientific approach called One Health. One Health is a problem-solving strategy that tackles issues at the interface of wildlife, domestic animal and human health. A monumental effort by veterinarians and other scientists, working with communities and animal health organisations, has teased out a solution. Instead of looking at livestock’s geographic origin, it looks at the meat production process itself – from farm to fork – through a food safety lens.

This approach was initially developed for astronauts in the 1960s to avoid illness from contaminated food. It is now used throughout the food industry, from growing vegetables, to canning fruit and processing meat. For beef, it means that even in foot-and-mouth zones, a combination of vaccination, veterinary surveillance, and standardised meat preparation ensures disease-free, wildlife-friendly beef.

But it is one thing to have the solution, and quite another to convince policy makers to implement it. The focus of the One Health team soon turned to policy and advocacy. After years of research and dialogue between sectors that rarely sat at the same table, in 2012 the Southern African Development Community (SADC) issued The Phakalane Declaration on Adoption of Non-Geographic Approaches for Management of Foot and Mouth Disease.

Put simply, these new “non-geographic approaches” are not reliant on fencing.

Policy into practice

This consensus statement from southern African animal health experts was a shot heard ‘round the world. A genuine policy breakthrough finally came in 2015, in Paris, where the World Animal Health Organisation (OIE) rewrote the Terrestrial Animal Health Code to allow for international trade of fresh meat from countries or zones with foot-and-mouth disease.

Since then, Ngamiland, home to world-renowned wildlife and the recently World Heritage-listed Okavango Delta, committed late last year to reassessing its fences with wildlife-friendly beef and wildlife concerns in mind.

Okavango Delta, Botswana.
Wikimedia Commons, CC BY

Botswana is also at the centre of the Kavango Zambezi Transfrontier Conservation Area which spans parts of Angola, Botswana, Namibia, Zambia and Zimbabwe, and is home to the world’s largest remaining population of elephants. The Animal and Human Health for the Environment And Development (AHEAD) program, based at Cornell University, have been working with local partners to resolve FMD-related conflicts in the largest peace park in Africa. Meanwhile, non-fence solutions were at the forefront of a recent multi-country summit in late 2016.

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Read more:
It’s time to stand tall for imperilled giraffes

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The new meat processing-focused approach seems like common sense but, after generations of conflict, it is bold and brave. Botswana, leading the charge, is now on the cusp of redeeming itself in the eyes of conservationists after 70 years of fence-related wildlife deaths.

Now, not only can this new way forward allow wildlife to rebound, but a regional economy benefiting from both wildlife and livestock can do the same – if policy-makers can indeed move – beyond fences.

Penny van Oosterzee, Adjunct Associate Professor James Cook University and University Fellow Charles Darwin University, James Cook University

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

Banded stilts fly hundreds of kilometres to lay eggs that are over 50% of their body mass

Banded Stilts feed on a range of invertebrates (including brine shrimp and snails) at saline wetlands across southern Australia.
Ben Parkhurst, Author provided

Reece Pedler, Deakin University; Andy T.D. Bennett, Deakin University, and Raoul Ribot, Deakin University

The hot, dry Australian desert may not come to mind as an ideal location for waterbirds to breed, but some species wait years for the opportunity to do just that.

New research has shed light on one of Australia’s most enigmatic birds, the banded stilt. This pigeon-sized shorebird has long been a source of intrigue due to its bizarre and extreme breeding behaviour. They fly hundreds or thousands of kilometres from coastal wetlands to lay eggs that are 50-80% of their body mass in normally dry inland desert salt lakes, such as Lake Eyre, on the rare occasions they are inundated by flooding rain.

Such behaviour has been a mystery for decades; described for the first time in 1930, just 30 breeding events had been documented for the entire species in the following 80 years.

To investigate this behaviour, and to assess the stilts’ conservation status, we began a study in 2011, during which I was based in outback South Australia, ready to jump into a small plane after every large desert rainfall. We also satellite-tagged nearly 60 banded stilts, using miniature solar powered devices around half the size of a matchbox.

Sixty banded stilts were tagged with solar-powered satellite trackers.
Author provided

This focused survey effort – which required overcoming the logistical challenges of very remote sites, knee-deep mud, heat and flies – has revealed major new insights into how banded stilts breed and the incredible distances they travel: we recorded one bird that flew 2,200km in just two nights.

Fast movers

The research revealed that, on average, banded stilts respond within eight days to unpredictable distant flooding of outback salt lakes. They leave their more predictable coastal habitat to travel 1,000-2,000km in overnight flights to arrive at the newly flooded lakes and take advantage of freshly hatched brine shrimp.

Brine shrimp eggs lie dormant in the lakes’ dry salt crust for years or decades between floods, but upon wetting they hatch in their billions, creating a “brine shrimp soup” – a rich but short-lived banquet for the nesting stilts.

Banded Stilt nests, with clutches of eggs representing over 50-80% of female body weight, litter an island in recently flooded Lake Ballard, in the Western Australian Goldfields 2014.
Lynn Pedler, Author provided

During the six-year study, we detected this nomadic movement and nesting behaviour seven times more often than it had been recorded in the previous 80 years. Although the banded stilts were previously thought to require large once-in-a-decade rains to initiate inland breeding, we found that small numbers of banded stilts respond to almost any salt lake inundation, arriving, mating and laying eggs equivalent of 50-80% of their body weight, despite high chances of the salt lake water drying before the eggs could hatch or chicks fledge.

Many times the eggs were abandoned as salt lake water dried. On other occasions some chicks survived long enough to learn to fly – although late-hatching chicks ran out of food or water and starved.

Once we found out that stilts needed much less rain to breed than previously thought, we used satellite imagery to reconstruct the past 30 years of flooding for ten salt lakes in South and Western Australia.

These models showed that conditions have been suitable for breeding more than twice as often as breeding events have actually been recorded. It seems that stilts’ nesting behaviour is so remote and hard to predict that scientists have been missing half the times it has happened.

Threats to banded stilt survival

Salt lakes in northwestern Australia are vital for banded stilts’ breeding. Our satellite tracking showed that birds from across the continent can reach these lakes after rain. Satellite images also suggested these lakes fill with water much more frequently than southern breeding sites.

These lakes are also largely free of native silver gulls (the common seagulls seen around our cities), which are predators of stilt chicks.

Silver Gulls fighting over a banded stilt chick on Lake Eyre. These gulls found in Australian cities also fly inland after rain and can decimate some Banded Stilt breeding attempts – eating thousands of eggs and chicks.
Reece Pedler, Author provided

But other southern Australian breeding lakes are dramatically affected by gull predation. In one instance, a colony of 9,500 pairs (around 30,000 eggs) had less than 5% of its chicks survive, despite abundant water and brine shrimp on offer. Observations made near the colony suggested that a chick was being eaten by gulls every two minutes. Nearly 900 chicks and 350 eggs were eaten in the 30 hours we watched the colony.

Unfortunately, even the lakes that are relatively gull-free are now under threat from human development, despite being in one of the most remote parts of the world. Lakes Disappointment, Mackay, Dora, Auld and others surrounding them in the Little Sandy and Great Sandy Deserts are the subject of plans for potash mining.

The most advanced plans relate to Lake Disappointment, where Reward Minerals plans to construct a series of drainage trenches and 4,000 hectares of evaporation ponds on the lake bed to harvest potash for use in fertilisers.

This action will create permanent brine pools in some parts of the lake, and prevent other areas from receiving any water. As surface water drains into evaporation ponds, it’s likely the first rains after a long dry spell will no longer prompt mass brine shrimp hatching. Without this brine shrimp “soup”, banded stilts cannot breed at the site.

A tiny island on Lake Torrens SA, covered by 70,000 Banded Stilt nests in 2010.
Paul Wainwright, Author provided

Meanwhile, the coastal habitat that supports banded stilt for the rest of the year is also changing. Sites that are home to thousands of birds, such as parts of the Dry Creek Saltfields and Bird Lake in South Australia, have been drained in the past two years.

If both the stilts’ inland breeding and coastal refuges are under threat, how can they survive?

Lessons for managing mobile species

This research offers insight into the conservation of highly mobile species, which may travel hundreds or thousands of kilometres in a year. Banded stilts are listed as vulnerable in South Australia, but have no conservation rating in the four other states in which they are found.

Individual banded stilts appear to operate over vast spatial scales, crossing between state jurisdictions in single overnight flights. Their episodic breeding events are hard to find and even more difficult to manage. Between breeding events, long-lived adults depend on refuges around the country which are being impacted by human activity, including potentially longer, harsher dry periods from climate change into the future.

These birds epitomise adaptation to unpredictable changes in their environment, but habitat loss and a warming climate may threaten them as much as any other species.

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The authors would like to acknowledge L. Pedler, M. Christie, B. Parkhurst, R. West, C. Minton, I. Stewart, M. Weston, D. Paton, B. Buttemer and the South Australian Department for Environment, Water and Natural Resources, and Western Australian Department for Parks and Wildlife._

Reece Pedler, PhD student, Deakin University; Andy T.D. Bennett, Professor, Deakin University, and Raoul Ribot, Lecturer in Ecology, Deakin University

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