Wednesday, February 19, 2020

Here are 5 practical ways trees can help us survive climate change

As the brutal reality of climate change dawned this summer, you may have asked yourself a hard question: am I well-prepared to live in a warmer world?

There are many ways we can ready ourselves for climate change. I'm an urban forestry scientist, and since the 1980s I've been preparing students to work with trees as the planet warms.

In Australia, trees and urban ecosystems must be at the heart of our climate change response.

Governments have a big role to play—but here are five actions everyday Australians can take as well.

1. Plant trees to cool your home

At the current rate of warming, the number of days above 40℃ in cities including Melbourne and Brisbane, will double by 2050—even if we manage to limit future temperature rises to 2℃.

Trees can help cool your home. Two medium-sized trees (8-10m tall) to the north or northwest of a house can lower the temperature inside by several degrees, saving you hundreds of dollars in power costs each year.

Green roofs and walls can reduce urban temperatures, but are costly to install and maintain. Climbing plants, such as vines on a pergola, can provide great shade, too.

Trees also suck up carbon dioxide and extend the life of the paint on your external walls.

2. Keep your street trees alive

Climate change poses a real threat to many street trees. But it's in everyone's interests to keep trees on your nature strip alive.

Adequate tree canopy cover is the least costly, most sustainable way of cooling our cities. Trees cool the surrounding air when their leaves transpire and the water evaporates. Shade from trees can also triple the lifespan of bitumen, which can save governments millions each year in road resurfacing.

Tree roots also soak up water after storms, which will become more extreme in a warming climate. In fact, estimates suggest trees can hold up to 40% of the rainwater that hits them.

But tree canopy cover is declining in Australia. In Melbourne, for instance, it falls by 1-1.5% annually, mainly due to tree removals on private land.

This shows state laws fail to recognize the value of trees, and we're losing them when we need them most.

Infrastructure works such as level crossing removals have removed trees in places such as the Gandolfo Gardens in Melbourne's inner north, despite community and political opposition. Some of these trees were more than a century old.

So what can you do to help? Ask your local council if they keep a register of important trees of your suburb, and whether those trees are protected by local planning schemes. Depending on the council, you can even nominate a tree for protection and significant status.

But once a development has been approved, it's usually too late to save even special trees.

3. Green our rural areas

Outside cities, we must preserve remnant vegetation and revegetate less productive agricultural land. This will provide shade and moderate increasingly strong winds, caused by climate change.

Planting along creeks can lower water temperatures, which keeps sensitive native fish healthy and reduces riverbank erosion.

Strategically planting windbreaks and preserving roadside vegetation are good ways to improve rural canopy cover. This can also increase farm production, reduce stock losses and prevent erosion.

To help, work with groups like Landcare and Greening Australia to vegetate roadsides and river banks.

4. Make plants part of your bushfire plan

Climate change is bringing earlier fire seasons and more intense, frequent fires. Fires will occur where they hadn't in the past, such as suburban areas. We saw this in the Melbourne suburbs of Bundoora, Mill Park, Plenty and Greensborough in December last year.

It's important to have a fire-smart garden. It might seem counter-intuitive to plant trees around the house to fortify your fire defenses, but some plants actually help reduce the spread of fire—through their less flammable leaves and summer green foliage—and screen your house from embers.

Depending on where you live, suitable trees to plant include crepe myrtle, the hybrid flame tree, Persian ironwood, some fruit trees and even some native eucalypts.

If you're in a bushfire-prone area, landscape your garden by strategically planting trees, making sure their canopies don't overhang the house. Also ensure shrubs do not grow under trees, as they might feed fire up into the canopy.

And in bad fire conditions, rake your garden to put distance between fuel and your home.

5. What if my trees fall during storms?

The fear of a whole tree falling over during storms, or shedding large limbs, is understandable. Human injury or death from trees is extremely rare, but tragedies do occur.

Make sure your trees are healthy, and their root systems are not disturbed when utility services such as plumbing, gas supplies and communication cables are installed.

Coping with a warming world

Urban trees are not just ornaments, but vital infrastructure. They make cities livable and sustainable and they allow citizens to live healthier and longer lives.

For centuries these silent witnesses to urban development have been helping our environment. Urban ecosystems depend on a healthy urban forest for their survival, and so do we.

Local water availability is permanently reduced after planting forests

No need to give up on crowded cities: We can make density so much better

by Thami Croeser and Lucy Gunn, The Conversation

The idea that we should decentralize our population has come up many times in Australia. Recently, the National Farmers' Federation president pushed the notion, calling for a shift to the regions. And the premise is this: city living is unpleasant. Roads are jammed, housing is expensive and it's all so much nicer out in the country. We need to "spread out."

We reject this conclusion. Regional centers certainly must play a role in accommodating our population growth, but for now it'll be a modest role.

The more immediate need is to focus on improving conditions in our major cities. Our smaller towns matter, but we can't neglect the urgent need to get better at doing the bigger ones right.

Our cities are growing very rapidly. The fastest growth is in Melbourne, which added 119,400 residents in 2017-18. That's nearly as many extra people as the entire population of Darwin in a single year. This rapid growth doesn't need to mean more traffic, ugliness or stratospheric housing prices and rents—if we confront a difficult truth.

A dirty word in Australia

The truth is we're just really ordinary at urban density. It's so poorly executed in Australian cities that it has become a dirty word in local politics.

Urban density targets remain low in planning policies for many states. It's often set at around 15 dwellings per hectare. In practice, even lower density is delivered.

Australians tend to think of density as living in high-rise tiny apartments. Drop the "d-word" at your local pub and see how the term "shoebox" or "vertical slum" quickly follows.

The irony is that the very thing that makes a getaway to central Paris or Barcelona so attractive is what many Australian city residents revile at home. The places we visit and admire are really quite dense.

Our estimates based on UN figures suggest Paris averages around 213 people per hectare and Barcelona 156. (By contrast, Melbourne averages 38 people per hectare and Sydney around 50.)

It's higher-density living that makes their streets and public spaces buzz. But, importantly, this density is achieved through a combination of well-designed mid-rise apartments (roughly six stories) close to shops, services and public transport. This gives residents the best of both worlds: cities that are livable and likable.

A failure of planning

Past failed experiments in density have made it difficult to replicate overseas examples locally. The great Australian dream of owning a quarter-acre block and the stigma around density persist with reason. In Melbourne, for example, rapid high-rise development in the last decade has delivered large numbers of very small apartments, in some cases of poor quality and lacking natural light and ventilation.

Very modest investment in public transport makes things worse, as new residents try to cram onto services that haven't kept pace with growth. Car parking, however, is usually mandated. These planning rules mean the price of new apartments includes the expense of multiple floors of parking, and streetscapes are peppered with vehicle crossover ramps.

Without adequate public transport, roads fill with cars, stoking resident opposition to further infill development. The roads and parking these cars need occupy valuable space, which could be better used for trees and urban greening. Green space is often overlooked in the haste to accommodate rapid population growth, yet it's essential for community health and well-being and for reducing urban heat island effects.

Handling population growth doesn't require us to move to Tamworth or Toowoomba, but it will require some really important changes in our urban development priorities. There has to be a much stronger focus on quality and aesthetics to win back public support for infill development. It's also going to take commitment to lift density targets in key planning policies.

Life on a Dutch woonerf.

Plan Melbourne's 2017 refresh, for instance, has moved to a goal of "over 20 dwellings per hectare." It follows the recommendations of research in allowing higher densities in high-activity areas such as activity or town centers. However, it will take time to implement this change in existing and new areas across the city.

Density must be complemented by suitable streetscapes and infrastructure. This will require a significant rethink of the role of the car in urban areas, greater investment in public transport, and a reallocation of large areas of streetscape space to greenery and pedestrians.

That's a big ask, but it's worth it, because density really doesn't have to mean "dogbox."

Dutch show change is possible

Take a (digital) walk around a woonerf neighborhood in the Netherlands, and you'll notice on-street parking is scant, the speed limit is around 15km/h and plentiful road space is allocated to tree planting and garden beds. Kids play in the street under the watchful eye of long-term locals. You don't notice the dense apartments around you because there are trees in the way and there's a lot to see at ground level.

Remarkably, it was only in the 1970s that the Dutch started to move away from car-oriented planning to deliver this kind of urban design, which puts people and place first. With courageous policy change, we could have this in Australia too.Superblocks currently transforming Barcelona might work in Australian cities, tooProvided by The Conversation

Emergency Recovery Plan could halt catastrophic collapse in world's freshwater biodiversity

by WWF

With biodiversity vanishing from rivers, lakes and wetlands at alarming speed, a new scientific paper outlines an Emergency Recovery Plan to reverse the rapid decline in the world's freshwater species and habitats—and safeguard our life support systems.

Published today in BioScience, the Emergency Recovery Plan calls for the world to take urgent steps to tackle the threats that have led to an 83% collapse in freshwater species populations and the loss of 30% of freshwater ecosystems since 1970—ecosystems that provide us with water, food, livelihoods, and protection from floods, droughts and storms.

Developed by a global team of scientists from WWF, International Union for Conservation of Nature (IUCN), Conservation International, Cardiff University and other eminent organizations and academic institutions, this is the first comprehensive plan to protect and restore freshwater habitats, which host more species per square kilometer than land or oceans—and are losing this extraordinary biodiversity two or three times faster.

The six-point plan prioritizes solutions that are rooted in cutting edge science and have already proven successful in certain locations: letting rivers flow more naturally, reducing pollution, protecting critical wetland habitats, ending overfishing and unsustainable sand mining in rivers and lakes, controlling invasive species, and safeguarding and restoring river connectivity through better planning of dams and other infrastructure.

Critically, with governments meeting in November to agree on a new global deal to conserve and restore biodiversity at a landmark conference of the Convention on Biological Diversity, the authors recommend some new targets, including on restoring water flows, controlling illegal and unregulated sand mining in rivers, and improving management of freshwater fisheries that feed hundreds of millions of people.

"Nowhere is the biodiversity crisis more acute than in the world's rivers, lakes and wetlands—with over a quarter of freshwater species now heading for extinction. The Emergency Recovery Plan can halt this decades-long decline and restore life to our dying freshwater ecosystems, which underpin all of our societies and economies," said Dave Tickner, WWF-UK Chief Freshwater Advisor and lead author on the paper.

Covering approximately 1% of the Earth's surface, rivers, lakes and freshwater wetlands are home to 10% of all species and more described fish species than in all the world's oceans. But they are rapidly disappearing with populations of freshwater megafauna—such as river dolphins, sturgeon, beavers, crocodiles and giant turtles—crashing by 88% in the past half century.

"The causes of the global collapse in freshwater biodiversity are no secret, yet the world has consistently failed to act, turning a blind eye to the worsening crisis even though healthy freshwater ecosystems are central to our survival. The Emergency Recovery Plan provides an ambitious roadmap to safeguarding freshwater biodiversity—and all the benefits it provides to people across the world," said co-author, Professor Steven Cooke of Carleton University in Canada.

The Emergency Recovery Plan highlights a variety of measures that together will transform the management and health of rivers, lakes and wetlands, such as treating more than 20% of sewage before it is flushed into nature, avoiding dams on the world's remaining free flowing rivers, and expanding and strengthening protected areas in partnership with local communities.

"All the solutions in the Emergency Recovery Plan have been tried and tested somewhere in the world: they are realistic, pragmatic and they work. We are calling on governments, investors, companies and communities to prioritize freshwater biodiversity—often neglected by the conservation and water management worlds. Now is the time to implement these solutions, before it is too late," said James Dalton, Director of IUCN's Global Water Programme.

"We have the last opportunity to create a world with rivers and lakes that once again teem with wildlife, and with wetlands that are healthy enough to sustain our communities and cities, but only if we stop treating them like sewers and wastelands," said Tickner. "This decade will be critical for freshwater biodiversity: countries must seize the chance to keep our life support systems running by ensuring freshwater conservation and restoration are central to a New Deal for Nature and People."

An 88 percent decline in large freshwater animals

More information: David Tickner et al. Bending the Curve of Global Freshwater Biodiversity Loss: An Emergency Recovery Plan, BioScience (2020). DOI: 10.1093/biosci/biaa002

Uganda army fights voracious desert locusts

by Michael O'hagan

Locusts swarms are threatening food supplies in East Africa, where 12 million are already going hungry

Under a warm morning sun scores of weary soldiers stare as millions of yellow locusts rise into the northern Ugandan sky, despite hours spent spraying vegetation with chemicals in an attempt to kill them.

From the tops of shea trees, fields of pea plants and tall grass savanna, the insects rise in a hypnotic murmuration, disappearing quickly to wreak devastation elsewhere.

The soldiers and agricultural officers will now have to hunt the elusive fast-moving swarms—a sign of the challenge facing nine east African countries now battling huge swarms of hungry desert locusts.

They arrived in conflict-torn South Sudan this week, with concerns already high of a humanitarian crisis in a region where 12 million are going hungry, according to the UN's Food and Agriculture Organization (FAO).

"One swarm of 40 to 80 million can consume food" for over 35,000 people in a day, Priya Gujadhur, a senior FAO official in Uganda, told AFP.

In Atira—a remote village of grass-thatched huts in northern Uganda—some 160 soldiers wearing protective plastic overalls, masks and goggles sprayed trees and plants with pesticide from before dawn in a bid to kill the resting insects.

But even after hours of work they were mostly able to reach only lower parts of the vegetation.

Large swarms of locusts can in a single day consume enough vegetation to feed 35,000 people

Major General Kavuma sits in the shade of a Neem Tree alongside civilian officials as locusts sprayed with pesticide earlier that morning fall around them, convulsing as they die.

An intense chemical smell hangs in the air.

'They surrounded me'

Zakaria Sagal, a 73-year-old subsistence farmer was weeding his field in Lopei village some 120 kilometres (75 miles) away, preparing to plant maize and sorghum, when without warning a swarm of locusts descended around him.

"From this side and this side and this side, they surrounded me," Sagal said, waving his arms in every direction.

"We have not yet planted our crops but if they return at harvest time they will destroy everything. We are not at all prepared."

East Africa's regional expert group, the Climate Prediction and Applications Centre (ICPAC), warned Tuesday that eggs laid across the migratory path will hatch in the next two months, and will continue breeding as the rainy season arrives in the region.

This will coincide with the main cropping season and could cause "significant crop losses... and could potentially worsen the food security situation", ICPAC said in a statement.

Soldiers have been deployed in Uganda to spray trees and savannas in a bid to beat back the infestation

'Panic mode'

Since 2018 a long period of dry weather followed by a series of cyclones that dumped water on the region created "excessively ideal conditions" for locusts to breed, says Gujadhur.

Nevertheless, governments in East Africa have been caught off guard and are currently in "panic mode" Gujadhur said.

The locusts arrived in South Sudan this week after hitting Ethiopia, Somalia, Kenya, Djibouti, Eritrea, Tanzania, Sudan and Uganda.

Desert locusts take over on a dizzying scale.

One swarm in Kenya reached around 2,400 square kilometres (about 930 square miles)—an area almost the size of Moscow—meaning it could contain up to 200 billion locusts.

"A swarm that size can consume food for 85 million people per day," said Gujadhur.

Ugandan authorities are aware that subsequent waves of locusts may pose problems in the weeks to come, but in the meantime they are attempting to control the current generation.

Locust eggs laid across the migratory path will hatch in the next two months, allowing the insects to continue to wreak havoc

Gujadhur is quick to praise the "quite strong and very quick" response from the Ugandan government but is concerned that while the army can provide valuable personnel, a military-led response may not be as effective as is necessary.

"It needs to be the scientists and (agriculture officials) who take the lead about where the control operations need to be and how and when and what time," she said.

'They eat anything green'

The soldiers have been working non-stop for two days, criss-crossing the plains on the few navigable roads, trying to keep up with the unpredictable swarms.

Major General Kavuma recognises that the biggest threat is from the eggs which are yet to hatch but is confident the army will be able to control this enemy.

"We have the chemicals to spray them, all we need is to map the places they have been landing and sleeping," he said.

"In two weeks time we will come back and by that time they will have hatched and that will be the time to destroy them by spraying."

Locusts arrived in South Sudan this week after hitting Ethiopia, Somalia, Kenya, Djibouti, Eritrea, Tanzania, Sudan and Uganda

Back in Lopei village, Elizabeth Namoe, 40, a shopkeeper in nearby Moroto had been visiting family when the swarm arrived.

"When the locusts settle they eat anything green, the animals will die because they have nothing to feed on, then even the people (will suffer)," she said.

"The children will be affected by hunger and famine since all life comes from all that is green. I fear so much."

Locust swarms arrive in South Sudan, threatening more misery

Coronavirus outbreak slashes China carbon emissions: study

The coronavirus outbreak has hit the Chinese economy hard, but also lowered the country's carbon emissions as a result, researchers say

The coronavirus epidemic that has paralysed the Chinese economy may have a silver lining for the environment.

China's carbon emissions have dropped by least 100 million metric tonnes over the past two weeks, according to a study published on Wednesday by the Centre for Research on Energy and Clean Air (CREA) in Finland.

That is nearly six percent of global emissions during the same period last year.

The rapid spread of the novel coronavirus—which has killed over 2,000 and infected more than 74,000 people across China—has led to a drop in demand for coal and oil, resulting in the emissions slump, the study published on the British-based Carbon Brief website said.

Over the past two weeks, daily power generation at coal power plants was at a four-year low compared with the same period last year, while steel production has sunk to a five-year low, researchers found.

China is the world's biggest importer and consumer of oil, but production at refineries in Shandong province—the country's petroleum hub—fell to the lowest level since autumn 2015, the report said.

Economic activity in China usually picks up after the Lunar New Year holiday, which began on January 25.

But authorities extended the holidays this year—by a week in many parts of the country including Shanghai—in an effort to contain the epidemic by keeping people at home.

"Measures to contain coronavirus have resulted in reductions of 15 percent to 40 percent in output across key industrial sectors," the report said.

"This is likely to have wiped out a quarter or more of the country's CO2 (carbon dioxide) emissions over the past two weeks, the period when activity would normally have resumed after the Chinese New Year holiday."

But environmentalists have warned that the reduction is temporary, and that a government stimulus—if directed at ramping up production among heavy polluters—could reverse the environmental gains.

"After the coronavirus calms down, it is quite likely we will observe a round of so-called 'retaliatory pollutions' - factories maximising production to compensate for their losses during the shutdown period," said Li Shuo, a policy adviser for Greenpeace China.

"This is a tested and proven pattern."

Meanwhile, China's nitrogen dioxide emissions—a byproduct of fossil fuel combustion in vehicles and power plants—fell 36 percent in the week following the Lunar New Year holidays, compared with the same period a year earlier, according to another study by CREA that used satellite data.

New obstacles ahead in China's pollution fight: report

Image: International Space Station transits the moon

by European Space Agency

Say cheese.

Amateur astrophotographer Javier Manteca captured the International Space Station as flew in front of the moon on 5 February.

While most eyes were on the change of command ceremony taking place inside the Space Station ahead of ESA astronaut Luca Parmitano's return to Earth, Javier set up his gear to track the Station from the small town of Campo Real in Madrid, Spain.

Using a camera attached to a 150/750 telescope recording at 25 frames per second, Javier captured the 690 millisecond transit on video and composed this image made from 17 stacked frames.

For Javier, this was a moment two years in the making. He posted the image to his Twitter and Instagram, where you can find more of his work.

Luca returned to Earth the day after this photo, on 6 February, ending a record-breaking 201 days in space for his Beyond mission.

Highlights of his mission include four complex sorties that earned him the European record for most cumulative hours spent on spacewalks, remotely operating a rover in the Netherlands from space, and being the first Italian European commander of the Station.

Another European milestone was met this week. The Orion spacecraft that will fly around the moon on the Artemis-1 mission completed thermal-vacuum testing in the world's largest vacuum chamber at NASA's Plum Brook Station in Ohio, U.S..

ESA's contribution to the mission is the European Service Module that will power the vehicle as well as provide electricity, water, oxygen and nitrogen and keep the spacecraft at the right temperature and on course.

From 26 December until 9 February, the spacecraft was subjected to environmental temperatures varying from –175°C to 75°C to give it its first taste of space.

NO BUTTER, NO LEMON, NO WHITE WINE

Half a million mussels cooked to death at a New Zealand beach

Business Insider•February 15, 2020

New Zealand resident Brandon Ferguson discovered over 500,000 dead mussels and shells when he went walking along the shores of the Maunganui Bluff Beach in the country's North Island.

Ferguson told Business Insider that he had witnessed this type of event on the same beach in the past, with different types of shellfish washing up dead along the shores.

One expert said the mussels had essentially cooked to death due to hot weather and mid-day low tides.

Ferguson shared a video of the experience in the hopes that the global community would take notice of the effects of climate change happening right outside his doorstep.

steamed mussels

Shutterstock/135pixels

Hundreds of thousands of mussels cooked to death in New Zealand due to rising temperatures in New Zealand's oceans.

New Zealand resident Brandon Ferguson posted a video on Facebook from Maunganui Bluff Beach, located on the country's North Island, showing hundreds-of-thousands of dead mussels that had washed up on the shore.

Ferguson told Business Insider that he happened upon the sight while out with friends and family last week.

"I'm local to the area so I'm always out on 'the coast' gathering food for the family," he said. "That day I was out with friends and family while they were fishing. We waited for the tide to turn so we could gather mussels."

But instead, Ferguson saw hundreds of thousands of green-lipped mussels that had turned up dead.

"It smelled like dead rotting seafood," Ferguson said. "Some of the mussels were empty, some of them were dead ... Some were just floating around in the tide."

"There were well over 500,000 mussels and shells littering the coastline."

Mussels that washed up on the Maunganui Bluff Beach in Aranga, New Zealand.

Brandon Ferguson

Ferguson said that he had witnessed this type of event on the same beach in the past, with different types of shellfish washing up dead along the shores. He blamed rising temperatures and warming sea waters for the phenomena.

"It has happened in the past due to warm water temperatures, low mid-day tides, and high pressures," he said.

A 2019 report from the New Zealand government supports Ferguson's theory — climate change has been warming sea temperatures, devastating the country's native marine plants, animals and habitats.

According to the report, between 1981 and 2018, overall sea-surface temperatures across New Zealand's four oceanic regions, including Chatham Rise, the Tasman Sea, subtropical, and subantarctic increased between 0.1 and 0.2 degrees Celsius per decade.

"New Zealand's oceans act like a giant sponge against the effects of climate change," New Zealand's Secretary for the Environment Vicky Robertson wrote in the report. "It's likely our seas take up more carbon dioxide than our forests, but there is only so much they and the life in them can take – and the limits aren't yet known."

Robertson explained that the warmer the water gets, the less able it is to absorb greenhouse gases like carbon dioxide, which have been increasingly released into the atmosphere and have a strong impact on climate change.

"The growth of species in the oceans is affected, and coastal communities and habitats are at risk from flooding and sea-level rise," Robertson said.

In December, a 386,000-square-mile chunk of the Pacific Ocean east of New Zealand rose about 10 degrees Fahrenheit warmer than average, threatening the survival of fish and coral in the region.

Andrew Jeffs, a marine scientist at the University of Auckland, told the New Zealand Herald that the mussels in Ferguson's video likely died from "heat stress" brought on by hot weather and mid-day low tides.

"The mussels die of heat stress. You imagine lying in the midday sun every day for four hours for the best part of a week. You'd be pretty sunburnt at the end of that," he told The Herald.

Jeffs added the stark prediction that soon the mollusks may disappear entirely from New Zealand as temperatures continue to rise.

"In many other countries, we are seeing poleward movement of the distribution of the species as they adjust to temperature increases associated with climate change," he told the Herald. "I expect we may see the same in New Zealand."

Ferguson said he shared his video in the hopes that the global community would take notice of the effects of climate change happening right outside his doorstep.

"It's getting worse and worse every year," he told Business Insider. "At times like this we should wake up and start respecting these places and pay attention to what is happening before we lose our 'taonga' [a Māori word meaning 'treasure'] for good."

He says he is "heartbroken" to see the native sea life in his hometown disappear, and says he fears for the extinction of the species in the country.

"I fear that our next generation is going to miss out," he said. "Thats what hurts me the most."

Mussels 'cooked alive' in balmy New Zealand ocean

Mussels are sensitive to pollution and temperature change

Up to half a million mussels were effectively cooked in the wild in unusually balmy waters on the New Zealand coast in a massive "die-off" that marine experts have linked to climate change.

The dead molluscs were found by Auckland man Brandon Ferguson earlier this month at Maunganui Bluff Beach, near the northern tip of the North Island.

Footage posted to social media shows a stunned Ferguson wading through rockpools choked almost knee-deep with mussel shells remarking "they're all dead... there's nothing left".

Professor Chris Battershill, a marine ecologist at Waikato University, said there had been similar die-off in recent years involving tuatua cockles and clams.

"The common denominators seem to be really hot conditions with lots of sunlight and unusually calm waters for an extended period," he told AFP.

"This leads to a combination of heat stress and the animals running out of oxygen because the water's so still. They eventually succumb... they're effectively cooked alive."

Battershill the extreme conditions were unusual.

"Is it related to climate change, I think it is," he said.

"Mussels are hardy little animals—you think about when they're harvested they survive in the supermarket with just a little water on them.

"So it's taken extreme conditions to kill them. And when you have a number of die-offs in recent years involving a number of species then you really need to sit up and take notice."

University of Auckland marine scientist Andrew Jeffs said more mass die-offs were likely to occur as a result of climate change.

He said mussel populations would eventually move to cooler waters as temperatures rose.

"I am expecting that it is likely to ultimately result in the displacement of mussel beds from shores in northern parts of the country with them continuing to be found further south," he told AFP.

Australia's got mussels (but it could be a problem)

Researchers uncover the genetics of how corn can adapt faster to new climates

by University of Delaware

Maize is a staple food all over the world. In the United States, where it's better known as corn, nearly 90 million acres were planted in 2018, earning $47.2 billion in crop cash receipts.

But, under the effects of climate change, this signature crop may not fare so well. As the world tries to feed a population skyrocketing to nine billion by 2050, that has major implications. So, what can we do about it? The answer might be exotic.

A multi-institutional team led by University of Delaware plant geneticist Randy Wisser decoded the genetic map for how maize from tropical environments can be adapted to the temperate U.S. summer growing season. Wisser sees these exotic varieties, which are rarely used in breeding, as key to creating next-era varieties of corn.

The research team included scientists from UD, North Carolina State University, University of Wisconsin, University of Missouri, Iowa State University, Texas A&M University and the U.S. Department of Agriculture-Agricultural Research Service. The resulting study, highlighted by the editorial board of Genetics, provides a new lens into the future viability of one of the world's most important grains.

"If we can expand the genetic base by using exotic varieties, perhaps we can counter stresses such as emerging diseases and drought associated with growing corn in a changing climate," said Wisser, associate professor in UD's Department of Plant and Soil Sciences. "That is critical to ensuring ample production for the billions of people who depend on it for food and other products."

Modern maize strains were created from only a small fraction of the global maize population. This limited infusion of diversity raises concerns about the vulnerability of American corn in a shifting climate. The U.S. Department of Agriculture (USDA) seed bank includes tens of thousands of varieties, but many are just not being used.

"We know that the tropical maize varieties represent our greatest reservoir of genetic diversity," said study co-author Jim Holland, a plant geneticist with the USDA Agricultural Research Service at North Carolina State. "This study improved our understanding of those genetics, so we can use this information to guide future breeding efforts to safeguard the corn crop."

Certain exotic strains of maize better handle drought or waterlogging or low-nitrogen soil, for example. But because these strains have evolved outside the U.S., they are not immediately suited to states like Delaware. So, exotics first need to be pre-adapted.

In prior work, Wisser and his colleagues showed how 10 years of repeated genetic selection was required to adapt a tropical strain of maize to the temperate U.S. Co-author Arnel Hallauer spent a decade adapting the population through selective breeding, so it could flourish in an environment like Delaware.

"What's so cool now is that we could go back to the original generations from Dr. Hallauer and grow them side by side in the same field," Wisser said of the first-of-its-kind experimental design. "This allows us to rule out the influence of the environment on each trait, directly exposing the genetic component of evolution. This has opened a 'back to the future' channel where we can redesign our approach to developing modern varieties."

While extremely impressive, a decade to adapt exotic maize to new environments is a lot of time when the climate change clock is ticking.

"Unfortunately, this process takes 10 years, which is not counting ongoing evaluations and integrating the exotic variations into more commonly used types of maize," Wisser said. "With the climate threats we face, that's a long time. So, gaining insights into this evolutionary process will help us devise ways to shorten the time span."

Accelerating adaptation

Wisser isn't wasting any time as he explores ways to bolster corn's ability to survive and thrive. He and Holland are working on a new project to cut that time span in half.

In cutting-edge research funded by the U.S. Department of Agriculture's National Institute of Food and Agriculture, the team is analyzing how corn genomes behave in a target environment as they aim to formulate a predictive model for fitness.

"What we're doing is sequencing the genomes and measuring traits like flowering time or disease for individuals in one generation. From this, we can generate a lookup table that allows us to foresee which individuals in the next generation have the best traits based on their genetic profiles alone," Wisser said. "And our lookup table can be tailored to predict how the individuals will behave in a particular environment or location like Delaware."

That means plant breeders could grow a second generation of corn anywhere outside of Delaware, but still predict which individuals would be the most fit for Delaware's environment.

"For instance, even if the plants are grown at a location where a disease is not present, our prediction model can still select the resistant plants and cross them to enrich the genes that underlie resistance," Wisser said.

With this approach, researchers don't have to wait out a Delaware winter, so they can continue to pre-adapt the population for at least one extra generation per year. That's how 10 years of selective breeding for pre-adaptation could become five, providing a quicker route to access exotic genes.

This new effort connects to the Genomes To Fields (G2F) Initiative, developed in 2013 for understanding and capitalizing on the link between genomes and crop performance for the benefit of growers, consumers and society.

If Wisser and Holland can develop a method to rapidly pre-adapt exotics, this opens a lane for G2F to test the impact of these unique genomes on crop performance.

"Our goal is to advance the science so breeders can draw on a wider array of the diversity that has accumulated across thousands of years of evolution," explained Wisser, who has been involved in the public-private initiative since its beginning. "In turn, they can produce improved varieties for producers and consumers facing the challenges of climate change."

Researcher seeks holistic understanding of disease resistance in maize

More information: Randall J. Wisser et al. The Genomic Basis for Short-Term Evolution of Environmental Adaptation in Maize, Genetics (2019). DOI: 10.1534/genetics.119.302780

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