If you were a honeybee, how would you choose where to find flowers? Imagine your first flight out of the hive searching for food. What would you do if you saw flower patches with one flower, or three, or twelve, or twenty?
Our new study, published in the Journal of Experimental Biology, tested honeybees on exactly this question. We wanted to understand how honeybees choose where to forage in environments like greenhouses where our food is pollinated, in local parks, or in our own backyards.
Specifically, our research looked at whether honeybees with no specific numerical training could choose a flower patch based on the quantity of flowers it had.
We found the bees could tell the difference between groups of 1 vs 4 flowers – but not between, say, 4 vs 5. Basically, they couldn’t differentiate between groups of 2 or more flowers.
A mathematical matter of life and death
The ability to tell the difference between two quantities can mean life or death for an animal. “Quantity discrimination” can be vital for survival in tasks including:
resource comparison: choosing a larger quantity of food
aggressive interactions: choosing to avoid conflicts with larger groups of individuals, and
avoiding predators: choosing to stay with a larger group of animals of the same species to reduce your chance of being eaten.
We are gaining a better understanding of quantity discrimination across the animal kingdom. Primates and other mammals, amphibians, reptiles, birds and fish all display some form of quantity discrimination in day-to-day tasks. For example, fish use quantity discrimination to stay in larger groups to reduce the chance of being eaten by a predator.
However, little is known about spontaneous number choices by insects.
Honeybees typically visit around 150 individual flowers per flight from the hive to collect resources such as nectar or pollen. For a honeybee, a high quantity of flowers in a single area would mean less energy exertion than having to fly to many flower patches with less flowers.
Using different numbers of artificial flowers, we wanted to test whether individual honeybees could discriminate between a range of quantities, and how they might determine the quality of a flower patch.
Our honeybees were shown pairs of flower quantities ranging from easier number comparisons (such as 1 flower vs 12 flowers) to more challenging scenarios (such as 4 flowers vs 5 flowers).
Interestingly, despite previous findings that trained honeybees can discriminate between challenging quantities and can also learn to add and subtract, the bees performed poorly in our spontaneous number task.
We found they were only able to discriminate between 1 vs 3, 1 vs 4, and 1 vs 12 flowers – wherein they preferred the larger quantity. When 1 flower was an option they succeeded, but confused any comparisons between groups of 2 flowers or more.
This result suggests flower patch choice based on numerical-type cues is difficult for honeybees. And this has implications for how flower displays are interpreted.
With today being World Bee Day, why not take the opportunity to discover what bees are doing in gardens near you. Chances are they’re going to any flower patch with more than one flower, rather than paying much attention to absolute numbers.
The numbers of people cycling and walking in public spaces during COVID-19 has skyrocketed. Cities from Bogota to Berlin and Vancouver have expanded bike lanes and public paths to accommodate the extra cycling traffic. In Australia, the New South Wales government is encouraging councils to follow suit.
Mandatory social distancing under COVID-19 is disrupting the way we live and work, creating new lifestyle patterns. But once the crisis is over, will – and should – the picture return to normal?
That’s one of many key questions emerging as the precise effect of the pandemic on carbon emissions becomes clear.
Our research published today in Nature Climate Change shows how COVID-19 has affected global emissions in six economic sectors. We discovered a significant decline in daily global emissions – most markedly, on April 7.
The analysis is useful as we consider the deep structural change needed to shift the global economy to zero emissions.
Take, for example, our quieter streets. The fall in road traffic was a main driver of the global emissions decline. So, if we encourage cycling and working from home to continue beyond the current pandemic, our climate goals will become far more achievable.
Crunching the numbers
At the end of each year we publish the Global Carbon Budget – a report card on global and regional carbon trends. But the unusual circumstances this year prompted us to run a preliminary analysis.
We calculated how the pandemic influenced daily carbon dioxide emissions in 69 countries covering 97% of global emissions and six economic sectors.
It required collecting new, highly detailed data in different ways, and from diverse sources.
For example, we examined surface and air transport activity using data from TomTom and Apple iPhone direction requests, highway traffic records and airport departures. We used daily data to estimate changes in electricity usage.
And we built an index showing the level and size of the population under confinement in each country, to extrapolate the available data worldwide.
The pandemic’s peak
In early April, the reduction in global activity peaked. On April 7, global emissions were 17% lower than an equivalent day in 2019.
Total daily emissions in early April were similar to those observed in 2006. The fact that the world now emits as much under “lockdown” conditions as it did under normal conditions just 14 years ago underscores the rapid emissions growth in that time.
Road traffic contributed the most to the emissions decline (43%). The next biggest contributors were the power sector (electricity and heat) and industry (manufacturing and material production such as cement and steel). These three sectors combined were responsible for 86% of the fall in daily emissions.
The peak daily fall in global aviation activity (60%) was the largest of any sector we analysed. But aviation’s contribution to the overall fall in emissions was relatively small (10%) because it makes up just 3% of global emissions.
As people stayed at home, we found a small increase in global emissions from the residential sector.
In Australia, our widespread, high-level confinement triggered an estimated fall in peak daily emissions of 28% – two-thirds larger than the global estimate of 17%.
The 2020 outlook
We assessed how the pandemic will affect carbon dioxide emissions over the rest of 2020. Obviously, this will depend on how strong the restrictions are in coming months, and how long they last.
If widespread global confinement ends in mid June, we estimate overall carbon emissions in 2020 will fall about 4% compared to 2019. If less severe restrictions remain in place for the rest of the year, the reduction would be about 7%.
If we consider the various pandemic scenarios and uncertainties in the data, the full range of emissions decline is 2% to 13%.
Now for the important context. Under the Paris climate agreement and according to the United Nations Gap report, global emissions must fall by between 3% and 7% each year between now and 2030 to limit climate change well below 2℃ and 1.5℃, respectively.
Under our projected emissions drop, the world could meet this target in 2020 – albeit for the wrong reasons.
Stabilising the global climate system will require extraordinary changes to our energy and economic systems, comparable to the disruption brought by COVID-19.
A fork in the road
So how could we make this byproduct of the crisis – the emissions decline in 2020 – a turning point?
A slow economic recovery might lower emissions for a few years. But if previous global economic crises are any indication, emissions will bounce back from previous lows.
But it need not be this way. The recent forced disruption offers an opportunity to change the structures underpinning our energy and economic systems. This could set us on the path to decarbonising the global economy.
Let’s consider again the extra people now walking and riding bikes. What if governments took the chance now to support such active, low-emissions travel, and make it permanent? What if we accelerate the rollout of electric cars, bikes and scooters, to both broaden transport options and save lives through cleaner city air?
Encouragingly, the NSW government recently announced a A$15 million fund to help councils create bigger public thoroughfares and extra road crossings during the crisis. If the community embraces the changes, they may become permanent.
And Paris will invest €300 million (A$500 million) into a 650km bicycle network post-lockdown, including new “pop up” cycleways established during the pandemic.
The crisis has opened the way for other structural change. People and businesses have been able to test what travel is essential, and when alternative remote communication might be equally or more efficient.
Finally, energy and material consumption dropped during COVID-19. While such forced reductions are not a long-term answer to reducing greenhouse gas emissions, lower consumption can be achieved in other ways, such as new types of energy efficiency, that allow both environmentally sustainable development and rising well-being, incomes and activity.
We can rapidly return to the old “normal”, and the emissions pathway will follow suit. But if we choose otherwise, 2020 could be the unsolicited jolt that turns the global emissions trend around.
The intricacies of climate change policy have not been front of mind for the Australian government this last half year, but the issue is now back on the agenda. Yesterday a review chaired by energy industry executive Grant King into new low-cost sources of emissions reduction was released. The government has accepted many of its recommendations.
Federal energy minister Angus Taylor says the changes create new ways to reduce emissions across the industrial, manufacturing, transport and agriculture sectors.
The package spells a broadening of existing mechanisms and may open the door to some better outcomes. But the existing climate policy patchwork remains deeply inadequate, and in practice the changes may do little more than channel government funding to industry.
The role of carbon capture and storage and storage
In line with the review’s recommendation, the government’s emissions reduction fund will be extended to projects using carbon capture and storage (CCS) technology.
CCS involves capturing carbon dioxide from sources such as power stations, gas plants or cement plants and pumping it underground. It tends to be technically difficult and costly per unit of tonne of emissions saved, and usually does not capture all of the emissions.
The Emissions Reduction Fund (ERF) has been the government’s primary climate policy mechanism. It gives subsidies to projects that are deemed to reduce carbon emissions – to date, mainly in agriculture and forestry. The policy is vastly less effective and efficient than the carbon pricing mechanism it replaced in 2014.
The obvious criticism is that extending government support to CCS locks in some fossil fuel use, when Australia has great opportunities to put our energy system on a zero-emissions footing using cheap renewable energy.
However, in the path to decarbonising Australia’s economy, the technology may well have a role in some industrial applications such as cement production and natural gas processing. In principle it makes sense to include any technology in a policy mechanism, as long as it is cost-competitive.
In practice, carbon capture and storage projects in Australia would require far more to be economically feasible. This is because the additional cost per tonne of carbon dioxide removed is usually far higher than in typical agriculture and forestry projects. Replacing fossil fuels with renewable energy, or saving energy through better efficiency, is typically also far cheaper than cutting emissions through CCS.
So on present settings, where all project types receive the same rate of subsidy, including CCS might be mostly just a nod to the relevant interest groups. Methodologies for establishing and monitoring projects would be established by the bureaucracy but it seems unlikely that many projects would happen.
Energy technology support
The King review also calls for expanding the remit of the Australian Renewable Energy Agency (ARENA) and the Clean Energy Finance Corporation (CEFC) to make them “technology neutral”, so the agencies could support technologies across all sectors of the economy.
This implies expanding ARENA’s research and development activities, and the CEFC’s project finance, to the transport and industry sectors. These are the next big areas for decarbonisation after electricity, and it makes sense to channel resources into them.
A “technology neutral” approach could include carbon capture and storage. ARENA and CEFC make their own decisions about their investments within a broad mandate by government. It is important this remains so, allowing the most promising technologies to be supported, irrespective of the apparent preferences by government for fossil fuel-based technologies.
Broadening the ERF
The review recommends other changes to broaden the ERF, including to make it easier for smaller projects in agriculture and forestry to participate. This may have been prompted by the fact that the last two ERF auctions resulted in only a small number of projects and small volume of contracted emissions reductions.
This change may get extra projects over the line. But it does not fix the fundamental problem with the ERF, or its successor the Climate Solutions Fund.
The scheme pays businesses, in the form of credits, when they take steps to reduce emissions relative to a hypothetical baseline. Since it is generally impossible to know whether a company’s action to reduce emissions would have happened anyway, we can’t know to what extent claimed reductions are real. Despite elaborate estimation methodologies, the fundamental problem remains.
Under an effective and efficient climate policy framework, the ERF would either not exist or have a relatively minor role. But Australia is a long way from effective and efficient climate policy.
Softly, softly towards carbon trading?
Under the government’s Safeguard Mechanism, a company emitting carbon emissions beyond its baseline is required to buy emissions reductions credits to cover the excess.
But in practice, the baselines are set so high that projects rarely reach them, and those that do receive exemptions.
The new recommendation, accepted by the government, is to give emissions credits to companies that stay below their baselines, if it was the result of investment in “transformative” emissions-saving measures. This would create an incentive to do better, rather than just the existing, muted incentive not to do worse than a very unambitious standard.
The question is, who would buy these credits? The review suggests the government, or companies that exceed their baselines, might buy them. The former would expand the subsidy approach to emissions cuts even further. This is quite unnecessary: private money in industry is available for relevant investments if the right incentives or regulations are in place.
But what holds promise is if companies emitting over their baselines have to buy credits from companies that operate below the baseline.
That would create a form of carbon trading. There would be a market price for emissions in industry, and companies would move towards establishing cost-effective measures to curb emissions. There would be no money flowing to or from government, as trades would be only between companies.
The safeguard mechanism was originally designed with this possibility in mind, and perhaps now the door is opening a fraction.
But to create real demand for emissions credits, and a meaningful price on emissions in industry, emissions baselines would have to be drastically lowered and no more exemptions granted. Companies running old, inefficient equipment, of which there are many in Australia, would be put on the spot.
Given the government’s deep aversion to carbon pricing, and the likely opposition by some industry players, this is perhaps more pious hope than imminent prospect.
At least for now, we will probably only see a government-funded carrot given to some, and no stick. Government handouts to individual companies will continue to be the measure of Australia’s climate policy.
In these times of dramatic fiscal spending, sending a few more billion dollars of public money to businesses to subsidise new equipment may not seem a big deal. But one day, all that money needs to be recouped through taxation. It will then be obvious that industry should have been required to spend its own funds to cut emissions, and that a comprehensive market mechanism would have led to more efficient and productive investment choices.
Abolishing Australia’s carbon pricing mechanism in 2014 was a consequential failure of politics. The fine-tuning of the patchwork of policies that followed does not make up for it.
The fossil fuel lobby, led by the Minerals Council of Australia, seem pretty happy with the current system of environment laws. In a submission to a review of the Environment Protection and Biodiversity Conservation (EPBC) Act, it “broadly” supports the existing laws and does not want them replaced.
True, the group says the laws impose unnecessary burdens on industry that hinder post-pandemic economic recovery. It wants delays and duplication in environmental regulation reduced to provide consistency and certainty.
But for the fossil fuel industry to broadly back the current regime of environmental protection is remarkable. It suggests deep problems with the current laws, which have allowed decision-making driven by politics, rather than independent science.
So let’s look at the resources industry’s stance on environment laws, and what it tells us.
The Minerals Council’s submission calls for “eliminating or reducing duplication” of federal and state laws.
The fossil fuel lobby has long railed against environmental law – the EPBC Act in particular – disparaging it as “green tape” that it claims slows projects unnecessarily and costs the industry money.
On this, the federal government and the mining industry are singing from the same songbook. Announcing the review of the laws last year, the government flagged changes that it claimed would speed up approvals and reduce costs to industry.
Previous governments have tried to reduce duplication of environmental laws. In 2013 the Abbott government proposed a “one-stop shop” in which it claimed projects would be considered under a single environmental assessment and approval process, rather than scrutinised separately by state and federal authorities.
That proposal hit many political and other hurdles and was never enacted. But it appears to remain on the federal government’s policy agenda.
It’s true the federal EPBC Act often duplicates state approvals for mining and other activities. But it still provides a safety net that in theory allows the federal government to stop damaging projects approved by state governments.
The Commonwealth rarely uses this power, but has done so in the past. In the most famous example, the Labor party led by Bob Hawke won the federal election in 1983 and stopped the Tasmanian Liberal government led by Robin Gray building a major hydroelectric dam on the Gordon River below its junction with the Franklin River.
The High Court’s decision in that dispute laid the foundation for the EPBC Act, which was enacted in 1999.
In 2009 Peter Garrett, Labor’s then-federal environment minister, refused the Queensland Labor government’s proposed Traveston Crossing Dam on the Mary River under the EPBC Act due to an unacceptable impact on threatened species.
The Conversation put these arguments to the Minerals Council of Australia, and CEO Tania Constable said:
The MCA’s submission states that Australia’s world-leading minerals sector is committed to the protection of our unique environment, including upholding leading practice environmental protection based on sound science and robust risk-based approaches.
Reforms to the operation of the EPBC Act are needed to address unnecessary duplication and complexity, providing greater certainty for businesses and the community while achieving sound environmental outcomes.
But don’t change the current system much
Generally, the Minerals Council and other resources groups aren’t lobbying for the current system to be changed too much.
The groups support the federal environment minister retaining the role of decision maker under the law. This isn’t surprising, given a succession of ministers has, for the past 20 years, given almost unwavering approval to resource projects.
For example, in 2019 the then-minister Melissa Price approved the Adani coal mine’s groundwater management plan, despite major shortcomings and gaps in knowledge and data about its impacts.
When approached by The Conversation, the Minerals Council did not confirm it was referring to the New Acland project. Tania Constable said:
The case studies were submitted from a range of companies, and are representative of the regulatory inefficiency and uncertainty which deters investment and increases costs while greatly limiting job opportunities and economic benefits for regional communities from mining.
The New Acland mine expansion is on prime agricultural land on the Darling Downs, Queensland’s southern food bowl. Nearby farmers strongly opposed the project over fears of damage to groundwater, the creation of noise and dust, and climate change impacts.
But the Minerals Council fails to mention that since 2016, the mine has been building a massive new pit covering 150 hectares.
When mining of this pit began, the mine’s expansion was still being assessed under state and federal laws. Half of the pit was subsequently approved under the EPBC Act in 2017.
Based on my own research using satellite imagery and comparing the publicly available application documents, mining of West Pit started while Stage 3 of the mine was still being assessed under the EPBC Act. And after approval was given, mining was conducted outside the approved footprint.
The Conversation contacted New Hope Group, the company that owns New Acland mine, for comment, and they refuted this assertion. Chief Operating Officer Andrew Boyd said:
New Hope Group strongly deny any allegations that New Hope Coal has in any way acted unlawfully.
New Acland Coal had and still has all necessary approvals relating to the development of the pit Dr McGrath refers to. It is also not correct to say that the Land Court alerted the Department of its powers to act with regards to this pit.
The Department is obviously aware of its enforcement powers and was aware of the development of the pit well before 2018. Further, the Land Court in 2018 rejected Dr McGrath’s arguments and accepted New Acland Coal’s position that any issues relating to the lawfulness of the pit were not within the jurisdiction of the Land Court on the rehearing in 2018.
Accordingly, the lawfulness of the pit was irrelevant to the 2018 Land Court hearing.
Dr McGrath also fails to mention that his client had originally accepted in the original Land Court hearing (2015-2017) that the development of the pit was lawful only to completely change its position in the 2018.
State and federal environmental laws work in favour of the fossil fuel industry in other ways. “Regulatory capture” occurs when government regulators essentially stop enforcing the law against industries they are supposed to regulate.
This can occur for many reasons, including agency survival and to avoid confrontation with powerful political groups such as farmers or the mining sector.
In one apparent example of this, the federal environment department decided in 2019 not to recommend two critically endangered Murray-Darling wetlands for protection under the EPBC Act because the minister was unlikely to support the listings following a campaign against them by the National Irrigators Council.
Holes in our green safety net
Recent ecological disasters are proof our laws are failing us catastrophically. And they make the mining industry’s calls to speed-up project approvals particularly audacious.
Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.
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Almost every threat to modern humanity can be traced simply to our out-of-control population growth (think about arable land going to housing; continued growth in demand for petroleum fuels). Is anything being done to contain population growth on a national and international scale?
The question of population is more complex that it may seem – in the context of climate change as well as other issues such as biodiversity loss and international development.
As a starting point, let’s look at the statement “out-of-control population growth”. In fact, population growth is more “in control” than it has been for the past 50 years.
The global rate of population growth has been declining from just over 2% per year in 1970 to less than 1.1% in 2020 (and this estimate was made before COVID-19 erupted globally).
To put this in perspective, if the 2% growth rate had continued, the world’s population would have doubled in 35 years. At a 1.1% growth rate, it would now be set to double in 63 years – but the growth rate is still declining, so the doubling time will be lengthened again.
Population growth also varies significantly between countries. Among the 20 most populous countries in the world, three countries have growth rates of more than 2.5% – Ethiopia, Nigeria and the Democratic Republic of Congo – while Japan’s population is in decline (with a negative growth rate, -0.3%) and China, Russia, Germany and Thailand all have very low growth rates.
These growth rates vary in part because the population structures are very different across countries. Japan has an aged population, with 28% over 65 years and just 12% under 15 years. Nigeria has only 3% of people in the over-65 bracket and 44% under 15.
For comparison, 20% of New Zealanders are younger than 15 and 16% are older than 65. For Australia, the respective figures are 18% and 17%.
Migration also makes a significant contribution in some countries, propping up the working-age population and shaping the demographic structure. History and levels of economic development play an important role too: higher-income countries almost consistently have smaller families and lower growth rates.
Rise in consumption
It’s certainly valid to link population growth (even a more limited “in control” population growth) with climate change and loss of land. Everything else being equal, more people means more space taken up, more resources consumed and more carbon emitted.
But while population growth has slowed since the 1970s, resource consumption hasn’t. For example, there is no equivalent decline in fossil fuel use since the 1970s.
This is an area where not everyone is equal. If all people were to use the same amount of resources (fossil fuels, timber, minerals, arable land etc), then of course total resource use and carbon would rise. But resource use varies dramatically globally.
If we look at oil consumption per person in 2019, the average American used almost twice as much as someone in Japan, the second oil-thirstiest populous nation, and almost 350 times as much as a person living in the Democratic Republic of Congo.
It is an easy out for us in the industrialised world to say “out-of-control population growth” is killing the planet, when instead it is equally valid – but more confronting – to say our out-of-control consumption is killing the planet.
To come to the final part of the question: is anything being done to contain population growth, on a national or international scale?
Even if we set aside the argument above that population is not the only issue, or even the most significant one, in terms of threats to humanity, what factors might influence population growth in parts of the world where it is high?
Things are being done, but they may not be what most people expect. It has long been shown that as incomes rise and health care improves, more children survive and people tend to have smaller families.
This effect is not instantaneous. There is a lag where population growth rates might rise first before they begin to drop. This demographic transition is a relatively consistent pattern globally.
One study in 2016, drawing on World Bank population data across a wide range of countries, found:
… the main driver of overall fertility reduction is clearly the change in proportions of women at each education level.
In relation to climate change action, this study specifically notes:
It is education, or more specifically girls’ education, that is far more likely to result in lower carbon emissions than a shift to renewables, improved agricultural practices, urban public transport, or any other strategy now being contemplated.
Recent research looked at how the global population might change if we implemented the aspirations of the 17 UN Sustainable Development Goals. It found the change would be significant and could even mean the global population stabilises by mid-century.
No other event in our lifetimes has brought such sudden, drastic loss to Australia’s biodiversity as the last bushfire season. Governments, researchers and conservationists have committed to the long road to recovery. But in those vast burnt landscapes, where do we start?
We are among the wildlife experts advising the federal government on bushfire recovery. Our role is to help determine the actions needed to stave off extinctions and help nature recover in the months and years ahead.
Our first step was to systematically determine which plant and animal species and ecosystems needed help most urgently. So let’s take a closer look at how we went about it.
Sorting through the smoke
One way to work out how badly a species is affected by fire is to look at how much of its distribution – or the area in which it lives – was burnt.
This is done by overlapping fire maps with maps or records showing the species’ range. The greater the overlap, the higher the potential fire impact. But there are several complicating factors to consider:
1. Susceptibility: Species vary in how susceptible they are to fire. For instance, animals that move quickly – such as red-necked wallabies and the white-throated needletail – can escape an approaching fire. So too can animals that burrow deeply into the ground, such as wombats.
Less mobile animals, or those that live in vegetation, are more likely to die. We also considered post-fire recovery factors such as a species’ vulnerability to predators and reproductive rate.
2. What we know: The quality of data on where species occur is patchy. For example, there are thousands of records for most of Australia’s 830 or so bird species. But there are very few reliable records for many of Australia’s 25,000-odd plant species and 320,000-odd invertebrate species.
So while we can estimate with some confidence how much of a crimson rosella’s distribution burned, the fire overlaps for less well-known species are much less certain.
3. The history of threats: The impact of fires on a region depends on the extent of other threats, such as drought and the region’s fire history. The time that elapses between fires can influence whether populations have recovered since the last fire.
For instance, some plants reproduce only from seed rather than resprouting. Fires in quick succession can kill regrowing plants before they’ve matured enough to produce seed. If that happens, species can become locally extinct.
4. Fire severity: Some areas burn more intensely than others. High severity fires tend to kill more animals. They also incinerate vegetation and can scorch seeds lying in the soil.
Many Australian plant species are exquisitely adapted to regenerate and resprout after fire. But if a fire is intense enough, even these plants may not bounce back.
5. Already threatened?: Many species affected by these bushfires were already in trouble. For some, other threats had already diminished their numbers. Others were highly vulnerable because they were found only in very limited areas.
The bushfires brought many already threatened species closer to extinction. And other species previously considered secure are now threatened.
With these issues in mind, and with contributions from many other experts, we compiled lists of plant, invertebrate and vertebrate species worst-affected by the 2019-20 fires. A similar assessment was undertaken for threatened ecosystems.
Some 471 plant, 213 invertebrate and 92 vertebrate species have been identified as a priority for interventions. Most had more than half their distribution burnt. Many have had more than 80% affected; some had 100% burnt.
Priority invertebrates include land snails, freshwater crayfish, spiders, millipedes, beetles, dragonflies, grasshoppers, butterflies and bees. Many species had very small ranges.
For example, the inelegantly named Banksia montana mealybug – a tiny insect – existed only in the foliage of a few individuals of a single plant species in Western Australia’s Stirling Range, all of which were consumed by the recent fires.
Some priority plants, such as the Monga waratah, have persisted in Australia since their evolution prior to the break-up of the Gondwanan supercontinent about 140 million years ago. More than 50% of its current range burned, much at high severity. During recovery it is vulnerable to diseases such as phytophthora root rot.
Some priority vertebrates have tiny distributions, such as the Mt Kaputar rock skink that lives only on rocky outcrops of Mt Kaputar near Narrabri, New South Wales. Others had large distributions that were extensively burnt, such as the yellow-bellied glider.
The priority lists include iconic species such as the koala, and species largely unknown to the public, such as the stocky galaxias, a fish that lives only in an alpine stream near Cooma in NSW.
What’s being done
A federal government scheme is now allocating grants to projects that aim to help these species and ecosystems recover.
Affected species need immediate and longer-term actions to help them avoid extinction and recover. Critical actions common to all fire-affected species are:
careful management of burnt areas so their recovery isn’t compromised by compounding pressures
protecting unburnt areas from further fire and other threats, so they can support population recovery
rapid surveys to identify where populations have survived. This is also the first step in ongoing monitoring to track recovery and the response to interventions.
Targeted control of feral predators, herbivores and weeds is also essential to the recovery of many priority species.
In some rare cases, plants or animals may need to be moved to areas where populations were reduced or wiped out. Captive breeding or seed collection can support this. Such restocking doesn’t just help recovery, it also spreads the risk of population loss in case of future fires.
Long road back
The COVID-19 pandemic has led to some challenges in implementing recovery actions. Like all of us, state agency staff, NGOs, academics and volunteer groups must abide by public health orders, which have in some cases limited what can be done and where.
But the restrictions may also have an upside. For instance, fewer vehicles on the roads might reduce roadkill of recovering wildlife.
As states ease restrictions, more groups will be able to continue the recovery process.
As well as action on the ground, much planning and policy response is still required. Many fire-affected species must be added to threatened species lists to ensure they’re legally protected, and so remain the focus of conservation effort.
Fire management methods must be reviewed to reduce the chance of future catastrophic fires, and to make sure the protection of biodiversity assets is considered in fire management planning and suppression.
Last bushfire season inflicted deep wounds on our biodiversity. We need to deal with that injury. We must also learn from it, so we can respond swiftly and effectively to future ecological disasters.
Many species experts and state/territory agency representatives contributed to the analyses of priority species. Staff from the Department of Agriculture, Water and the Environment (especially the Environmental Resources Information Network (Geospatial and Information Analytics Branch), the Protected Species and Communities Branch and the Threatened Species Commissioner’s Office) and Expert Panel members also contributed significantly to this work.
The Southern Ocean circling Antarctica is one of Earth’s richest marine ecosystems. Its food webs support an abundance of life, from tiny micro-organisms to seals, penguins and several species of whales. But climate change is set to disrupt this delicate balance.
Antarctic krill – finger-sized, swarming crustaceans – might be small but they underpin the Southern Ocean’s food web. Our research published today suggests climate change will cause the ocean habitat supporting krill growth to move south. The habitat will also deteriorate in summer and autumn.
The ramifications will reverberate up the food chain, with implications for other Antarctic animals. This includes humpback whales that feed on krill at the end of their annual migration to the Southern Ocean.
What we found
Antarctic krill are one of the most abundant animal species in the world. About 500 million tonnes of Antarctic krill are estimated to exist in the Southern Ocean.
Antarctic krill play a critical role in the ocean’s food webs. But their survival depends on a delicate balance of food and temperature. Scientists are concerned at how climate change may affect their population and the broader marine ecosystem.
We wanted to project how climate change will affect the Southern Ocean’s krill “growth habitat” – essentially, ocean areas where krill can thrive in high numbers.
Krill growth depends largely on ocean temperature and the abundance of its main food source, phytoplankton (microscopic single-celled plants).
Under a “business as usual” climate change scenario, future changes in ocean temperature and phytoplankton varied depending on the region and season.
In the mid-low latitudes, our projections showed temperatures warmed towards the limits krill can tolerate. For example, by 2100 the waters during summer around South Georgia island warmed by 1.8℃.
Warming water was often accompanied by decreases in phytoplankton; in the Bellingshausen Sea during summer a 1.7℃ rise halved the available phytoplankton.
However, phytoplankton increased closer to the continent in spring and summer – most dramatically by 175% in the Weddell Sea in spring.
Across all seasons, krill growth habitat remained relatively stable for 85% of the Southern Ocean. But important regional changes still occurred.
Krill growth habitat shifted south as suitable ocean temperatures contracted towards the poles. Combined with changes in phytoplankton distribution, growth habitat improved in spring but deteriorated in summer and autumn.
This early end to the growth season could have profound consequences for krill populations. The krill life cycle is synchronised with the Southern Ocean’s dramatic seasonal cycles. Typically this allows krill to both maximise growth and reproduction and store reserves to survive the winter.
A shift in habitat timing could create a mismatch between these two cycles.
For example, female krill need access to plentiful food during the summer in order to spawn. Since larger females produce exponentially more eggs, a decline in summer growth habitat could result in smaller females and far less spawning success.
Why this matters
Krill’s significant role in the food chain means the impacts of these changes may play out through the entire ecosystem.
If krill shift south to follow their retreating habitat, less food would be available for predators on sub-Antarctic islands such as Antarctic fur seals, penguins and albatrosses for whom krill forms a significant portion of the diet.
In the past, years of low krill densities has coincided with declines in reproductive success for these species.
Shifts in krill habitat timing may also affect migratory predators. For example, each year humpback whales migrate from the tropics to the poles to feed on the huge amount of summer krill. If the krill peak occurs earlier in the season, the whales must adapt by arriving earlier, or be left hungry.
Changes to krill growth habitat may damage more than the ocean food web. Demand for krill oil in health supplements and aquaculture feed is on the rise, and krill are the target of the Southern Ocean’s largest fishery. Anticipating changes in krill availability is crucial to informing the fishery’s sustainable management.
Many environmental drivers interact to create good krill habitat. More research is required, including better models, and an improved understanding of what drives krill to reproduce and survive.
But by examining changes in phytoplankton, we’ve taken significant strides towards predicting climate change impacts on krill and the wider Antarctic marine ecosystem.