New Piece in The Conversation. More livestock, more carbon dioxide, less ice: the world’s climate change progress since 2019 is (mostly) bad news
By Thomas Newsome, Christopher Wolf and William Ripple
Back in 2019, more than 11,000 scientists declared a global climate emergency. They established a comprehensive set of vital signs that impact or reflect the planet’s health, such as forest loss, fossil fuel subsidies, glacier thickness, ocean acidity and surface temperature.
In a new paper published today in the journal BioScience, we show how these vital signs have changed since the original publication, including through the COVID-19 pandemic. In general, while we’ve seen lots of positive talk and commitments from some governments, our vital signs are mostly not trending in the right direction.
So, let’s look at how things have progressed since 2019, from the growing number of livestock to the meagre influence of the pandemic.
Is it all bad news?
No, thankfully. Fossil fuel divestment and fossil fuel subsidies have improved in record-setting ways, potentially signalling an economic shift to a renewable energy future.
However, most of the other vital signs reflect the consequences of the so far unrelenting “business as usual” approach to climate change policy worldwide.
Especially troubling is the unprecedented surge in climate-related disasters since 2019. This includes devastating flash floods in the South Kalimantan province of Indonesia, record heatwaves in the southwestern United States, extraordinary storms in India and, of course, the 2019-2020 megafires in Australia.
In addition, three main greenhouse gases — carbon dioxide, methane and nitrous oxide — set records for atmospheric concentrations in 2020 and again in 2021. In April this year, carbon dioxide concentration reached 416 parts per million, the highest monthly global average concentration ever recorded.
Last year was also the second hottest year in recorded history, with the five hottest years on record all occurring since 2015.
Ruminant livestock — cattle, buffalo, sheep, and goats — now number more than 4 billion, and their total mass is more than that of all humans and wild mammals combined. This is a problem because these animals are responsible for impacting biodiversity, releasing huge amounts of methane emissions, and land continues to be cleared to make room for them.
In better news, recent per capita meat production declined by about 5.7% (2.9 kilograms per person) between 2018 and 2020. But this is likely because of an outbreak of African swine fever in China that reduced the pork supply, and possibly also as one of the impacts of the pandemic.
Tragically, Brazilian Amazon annual forest loss rates increased in both 2019 and 2020. It reached a 12-year high of 1.11 million hectares deforested in 2020.
Ocean acidification is also near an all-time record. Together with heat stress from warming waters, acidification threatens the coral reefs that more than half a billion people depend on for food, tourism dollars and storm surge protection.
What about the pandemic?
With its myriad economic interruptions, the COVID-19 pandemic had the side effect of providing some climate relief, but only of the ephemeral variety.
But all of these are expected to significantly rise as the economy reopens. Indeed, global gross domestic product dropped by 3.6% in 2020, but is projected to rebound to an all-time high.
So, a major lesson of the pandemic is that even when fossil-fuel consumption and transportation sharply decrease, it’s still insufficient to tackle climate change.
There is growing evidence we’re getting close to or have already gone beyond tipping points associated with important parts of the Earth system, including warm-water coral reefs, the Amazon rainforest and the West Antarctic and Greenland ice sheets.
OK, so what do we do about it?
In our 2019 paper, we urged six critical and interrelated steps governments — and the rest of humanity — can take to lessen the worst effects of climate change:
- prioritise energy efficiency, and replace fossil fuels with low-carbon renewable energy
- reduce emissions of short-lived pollutants such as methane and soot
- curb land clearing to protect and restore the Earth’s ecosystems
- reduce our meat consumption
- move away from unsustainable ideas of ever-increasing economic and resource consumption
- stabilise and, ideally, gradually reduce human populations while improving human well-being especially by educating girls and women globally.
These solutions still apply. But in our updated 2021 paper, we go further, highlighting the potential for a three-pronged approach for near-term policy:
- a globally implemented carbon price
- a phase-out and eventual ban of fossil fuels
- strategic environmental reserves to safeguard and restore natural carbon sinks and biodiversity.
A global price for carbon needs to be high enough to induce decarbonisation across industry.
And our suggestion to create strategic environmental reserves, such as forests and wetlands, reflects the need to stop treating the climate emergency as a stand-alone issue.
By stopping the unsustainable exploitation of natural habitats through, for example, creeping urbanisation, and land degradation for mining, agriculture and forestry, we can reduce animal-borne disease risks, protect carbon stocks and conserve biodiversity — all at the same time.
Is this actually possible?
Yes, and many opportunities still exist to shift pandemic-related financial support measures into climate friendly activities. Currently, only 17% of such funds had been allocated that way worldwide, as of early March 2021. This percentage could be lifted with serious coordinated, global commitment.
Greening the economy could also address the longer term need for major transformative change to reduce emissions and, more broadly, the over-exploitation of the planet.
Our planetary vital signs make it clear we need urgent action to address climate change. With new commitments getting made by governments all over the world, we hope to see the curves in our graphs changing in the right directions soon.
Deer Movement and Genetics Project
We are seeking a PhD student to work on an exciting new project: Deer movement and genetics in the Australian Alps (NSW region) to inform pest management
In collaboration with the NSW National Parks and Wildlife Service (NPWS) Environment Trust Deer Project team we are seeking a PhD student to undertake the above project in Kosciuszko National Park (KNP) and adjacent privately managed lands.
Deer are considered pests in NSW and the Environment Trust has granted NPWS $9.2 million over 8 years to develop a cross tenure feral deer management plan, including the development of a cost-effective ‘toolkit’ for application across other areas of NSW. A key component of the project involves tracking the movements and population genetics of deer, as a complementary element to ongoing deer monitoring and integrated pest control trials.
Deer movement and genetics work:
The deer movement and genetics work will include: GPS collaring of sambar, red and fallow deer, collection of deer DNA and analysis of population structure (primarily sambar and fallow), collection of longitudinal deer behaviour knowledge from public and private land managers, and collection of ongoing observational data using qualitative and quantitative survey techniques.
This work will contribute the main elements of the PhD, which will answer the following:
To what extent can understanding the movements and behaviour of deer be integrated into pest management?
What are the implications for deer management across NSW and nationally?
How can behavioural responses of deer to intensive pest control influence pest management design and effort?
What is the local population structure and degree of interrelatedness of deer populations?
To what extent is there a local / external (inter or intra- district) population component? Can this knowledge be used to better focus management efforts?
Are there invasive source populations of deer affecting pest control efforts?
Are there barrier or conduits to deer movement through the landscape?
Benefits of the PhD project:
Significant in-kind project support via the Environmental Trust and NPWS Deer Project Team, including assistance in field work, equipment (aerial netting gear, GPS units, sampling kits, etc) and other key project costs. The student will be based at The University of Sydney in the School of Life and Environmental Sciences within the Global Ecology Lab supervised by Dr. Thomas Newsome and Dr. Catherine Grueber.
Australian candidates must be competitive to receive stipend support under the Research Training Program (RTP). A variety of scholarships are available for international students. The current RTP stipend rate at The University of Sydney is $35k tax free per annum. A top up scholarship of up to $10k per annum will be provided to a candidate who successfully receives an RTP stipend. If the selected candidate does not receive RTP support, we will consider funding a full scholarship at the rate of $40k per annum.
The expression of interest should include a cover letter and CV. Please include details of your degrees (including average marks), relevant work and research experience, field experience in remote locations, publications, and ability to use programs like GIS, statistical packages like R and/or experience undertaking genetic analyses. A shortlist of applicants may be required to interview or meet the project team. A single applicant will be selected for the position and invited to apply for stipend support. The student will enrol in Q3 2021 (enrolment and RTP applications are due to The University of Sydney by 30th March 2021).
Expressions of interest will close 26th February 2021.
In 2018 ProjectOzScav was initiated to investigate the role of carrion in ecological communities in Australia. Specifically, this project:
(1) explores how carrion is used by Australian vertebrates, arthropods and microbes,
(2) determines whether the presence of carrion has cascading impacts on surrounding live prey, and
(3) examines the effects of carrion on soil nutrients and subsequent plant growth surrounding the resource.
The Initial Field Work
PhD student Emma Spencer led the initial field work for ProjectOzScav, and has monitored vertebrate and insect scavengers, and soil and vegetation responses to the presence of 120 kangaroo carcasses across three study systems in Australia, representing temperate (Blue Mountains), subalpine (Kosciuszko National Park) and desert (Simpson Desert) biomes. This work has been supported by the Australian Pacific Science Foundation, Australian Geographic, The NESP Threatened Species Recovery Hub, Bush Heritage Australia, Emirates One&Only Wolgan Valley, The Holsworth Wildlife Endowment, NSW National Parks and Wildlife Service, and the Australian Academy of Science.
Insights from monitoring the carcasses have been featured in SMH, ABC, Newsweek, DailyMail, TheNewDaily, TheNorthWestStar, KatherineTimes, Batemans Bay Post, ABC news, NZHerald and various other news sources. The work led to blog posts featured by Bush Heritage, and the development of ideas to compost carcasses, especially when carcasses are in excess like after the recent bush fires. The research also helped to inform the debate about plans to ease restrictions on feral deer hunting.
Data collected so far has been incorporated into global analyses on the network structure of vertebrate scavenger assemblages, published in the journal Ecography. Observations of European wasps killing flies and stinging dingoes around carcasses were also published in the journal Food Webs, and featured in The Conversation. Emma is currently writing up the rest of her PhD chapters, and we will post updates when the work is published.
Unexpected Extreme Weather
Our carcass monitoring work to date coincided with a few extreme weather events. This included a flooding event in the Simpson Desert in 2019. Honours students Patrick Bragato and Zyna Krige are now analysing whether the behaviour, abundance and/or diversity of vertebrate scavenging assemblages around carcasses shifted as a result of the floods, and whether that in turn influences how long carcasses persist in the environment. The work will be based around monitoring vertebrate scavenger use of 40 kangaroo carcasses before the flood, and 40 carcasses after the flood.
In the Blue Mountains, our study site in the Wolgan Valley was severely burnt during the 2019/2020 bush fire season. We are now starting to assess whether the bush fires have altered scavenging dynamics and ecosystem processes around carcasses in that region. We monitored vertebrate and insect scavenger use of 80 kangaroo carcasses before the fires, and we are in the process of monitoring vertebrate and insect scavenger use of 40 kangaroo carcasses after the fires.
Other Field Research
Much of our current field research is being undertaken in and around Kosciuszko National Park. This research is supported by the Australian Alps Co-operative Management Program, The Hermon Slade Foundation, NSW National Parks, and local land managers. We are also collaborating on projects with the NSW Environment Trust funded Deer Project.
One project in Kosciuszko National Park is being led by PhD student Stefanie Bonat who is evaluating the ecological effects of animal mass mortality events. Stefanie’s project will monitor a suite of ecosystem responses to animal mass mortality events by simulating them in the field (monitoring lots of carcasses), and by studying what happens across the broader landscape after large scale culling events. A key focus will be the responses by scavengers, soil and vegetation to the presence of large numbers of carcasses in the landscape.
The second project in Kosciuszko National Park, led by Masters students James Vandersteen and Chris Fust, is assessing in more detail the impacts of European wasps on scavenging dynamics (building on the work published in Food Webs), how scavenging dynamics changes through different seasons, and also what happens to carcasses when different scavengers are excluded from accessing them. Previous work in Kosciuszko National Park identified that feral pigs are a dominant scavenger. Honours student Molly Kane is now assessing feral pig behaviours around carcasses, and the factors that influence their rates of scavenging.
The Next Steps and Opportunities for Students
As our field work progresses and our results written up, there are plenty of opportunities to join our team either as a volunteer, honours, masters or PhD student.
Some options for lab based volunteer work include (1) scavenging insect ID and sorting, (2) tagging photos of vertebrate scavengers, (3) plant ID’s, and (4) analysis of soil chemistry.
Some options for field based volunteer work include assisting with existing field work in Kosciuszko National Park. We are especially looking for volunteers to assist with field work for the mass mortality project, which will be fully operational in the field from August 2020.
In terms of opportunities for student projects, there is currently scope to add students to the mass mortality project and for the longer term carcass monitoring work we will be conducting in and around Kosciuszko National Park.
We are also looking for students to explore the factors affecting the diversity and abundance of scavenging insect assemblages that we have collected to date, and to explore the longer term impacts of carcasses on insect community assemblages.
For further details about student opportunities, see the Student Opportunities Page.
If you are interested to learn more about ProjectOzScav or whether carcass monitoring might be useful for research, conservation or land management please feel free to contact us directly via the following email: email@example.com
Photos and interesting findings can be followed on twitter via #ProjectOzScav
Thanks to all our funders and collaborators who have helped to make all this work to date possible.
Published today in The Conversation
Exactly 40 years ago, a small group of scientists met at the world’s first climate conference in Geneva. They raised the alarm about unnerving climate trends.
Today, more than 11,000 scientists have co-signed a letter in the journal BioScience, calling for urgently necessary action on climate.
This is the largest number of scientists to explicitly support a publication calling for climate action. They come from many different fields, reflecting the harm our changing climate is doing to every part of the natural world.
Why no change?
If you’re thinking not much has changed in the past 40 years, you might be right. Globally, greenhouse gas emissions are still rising, with increasingly damaging effects.
Much of the focus to date has been on tracking global surface temperatures. This makes sense, as goals like “prevent 2℃ of warming” create a relatively simple and easy-to-communicate message.
However, there’s more to climate change than global temperature.
In our paper, we track a broader set of indicators to convey the effects of human activities on greenhouse gas emissions, and the consequent impacts on climate, our environment, and society.
The indicators include human population growth, tree cover loss, fertility rates, fossil fuel subsidies, glacier thickness, and frequency of extreme weather events. All are linked to climate change.
Troubling signs over the past 40 years
Profoundly troubling signs linked to human activities include sustained increases in human and ruminant populations, global tree cover loss, fossil fuel consumption, number of plane passengers, and carbon dioxide emissions.
The concurrent trends on the actual impacts of climate change are equally troubling. Sea ice is rapidly disappearing, and ocean heat, ocean acidity, sea level, and extreme weather events are all trending upwards.
These trends need to be closely monitored to assess how we are responding to the climate emergency. Any one of them could hit a point of no return, creating a catastrophic feedback loop that could make more regions of Earth uninhabitable.
The need for better reporting
We urge national governments to report on how their own results are trending. Our indicators will allow policymakers and the public to better understand the magnitude of this crisis, track progress, and realign priorities to alleviate climate change.
Some of the indicators could even be presented monthly to the public during news broadcasts, as they are arguably more important than the trends in the stock exchange.
It’s not too late to act
In our paper we suggest six critical and interrelated steps that governments, and the rest of humanity, can take to lessen the worst effects of climate change:
- prioritise energy efficiency, and replace fossil fuels with low-carbon renewable energy sources,
- reduce emissions of short-lived pollutants like methane and soot,
- protect and restore the Earth’s ecosystems by curbing land clearing,
- reduce our meat consumption,
- move away from unsustainable ideas of ever-increasing economic and resource consumption, and
- stabilise and ideally, gradually reduce human populations while improving human well-being.
We recognise that many of these recommendations are not new. But mitigating and adapting to climate change will entail major transformations across all six areas.
How can you help?
Individuals can make a difference by reducing meat consumption, voting for political parties and members of government bodies who have clear climate change policies, rejecting fossil fuels where possible, using renewable and clean sources of energy, reducing car and air travel, and joining citizen movements.
Lots of small changes will help inspire larger scale shifts in policy and economic frameworks.
As scientists, we urge widespread use of our indicators to track how changes across the six areas above will start to change our ecosystem trajectories.
The Ecological Effects of Animal Mass Mortality Events
We are seeking a PhD student to work on an exciting new project assessing the ecosystem effects of animal mass mortality events.
Animal mass mortality events (AMMEs) involve the rapid, catastrophic die-off of organisms. These events can produce many of tons of dead biomass in a single event, and they appear to be on the rise globally. In the past few years, Australia has witnessed a number of AMMEs, including the death of a million fish in the Murray Darling Basin due to algal blooms, thousands of cattle dying after floods in Queensland, the deaths of feral horses in central Australia from drought, and thousands of flying foxes dying from heat stress in New South Wales and Queensland. Humans also effectively simulate AMMEs when they undertake large scale culling of overabundant species. But while the causes of these events are known (e.g. poor water quality, drowning, drought, heat, and direct killing), we know very little about the consequences of AMMEs for ecosystems. For example: can vertebrate and invertebrate scavenger assemblages consume and disperse the vast quantities of carcasses that become available? Do carcasses attract and get scavenged by pest species? Do unconsumed carcasses result in unusual and excessive nutrient loads in surrounding areas, and does this affect plant growth, weed invasion, or have cascading effects on herbivore grazers? This PhD project will answer these fundamental questions by simulating and monitoring AMMEs in the field. A key focus of the project will be the responses by scavengers including dingoes, red foxes, feral pigs, eagles, ravens, blowflies, and European wasps.
The project has financial support from the Hermon Slade Foundation and in-kind support from a major NSW Environment Trust project led by the NSW National Parks and Wildlife Service.
The field work will be in and around Kosciuszko National Park, and the student will work with local land managers and NSW Government Departments, including NSW National Parks and Wildlife Service, Department of Planning, Industry and Environment, and South East Local Land Services. The student will have an opportunity to work with colleagues in southern USA replicating similar experiments in systems where vultures and coyotes are the dominant scavengers. Support will also be provided from Dr. Philip Barton at Australian National University, Prof. Richard Duncan at University of Canberra, and Dr. Alex Carthey at Macquarie University.
Australian candidates must be competitive to receive funding under the Research Training Program. However, a top-up scholarship of up to $6,000 per annum will be offered to the successful applicant. A variety of scholarships are available for international students.
The student will be based at The University of Sydney in the School of Life and Environmental Sciences Ecology, Evolution and Environment Cluster, within the Global Ecology Lab.
For more information and to submit an expression of interest, please contact Dr. Thomas Newsome at firstname.lastname@example.org
The expression of interest should include a cover letter and CV. Please include details of your degrees (including average marks), work and research experience, field experience in remote locations, publications, and ability to use programs like GIS, and statistical packages like R. You must have a current manual drivers license. The project can commence either in late 2019, or early 2020, and will run for at least three years.
Expressions of interest will close July 30th 2019
You can download a copy of the flyer HERE
Further details on enrollment at The University of Sydney can be found below:
Carrion is a nutrient- and energy-rich resource that is used by a variety of organisms, particularly carnivorous vertebrates, arthropods and microbes. It can influence the movements and spatial distribution of scavenging species and, as many scavengers are also predators, the presence of carrion may have cascading effects on live prey.
The degradation of a carcass further influences soil properties, as well as the growth of certain plant species in the vicinity of the resource. Thus, carrion has the potential to affect many aspects of community ecology, and to play key roles in nutrient cycling and in shaping food-web dynamics through both direct and indirect pathways.
But despite the potential community-wide impacts of this resource, carrion ecology remains understudied, and research on the topic is primarily northern hemisphere based.
A new project to fill the knowledge gaps
Project OzScav’s main directive is to investigate the role of carrion in ecological communities in Australia.
Specifically, this project:
(1) explores how carrion is used by Australian vertebrates, arthropods and microbes,
(2) determines whether the presence of carrion has cascading impacts on surrounding live prey, and
(3) examines the effects of carrion on soil nutrients and subsequent plant growth surrounding the resource.
The project currently spans three study systems across Australia, representing temperate, subalpine and desert biomes.
Data are providing insight into the role of carrion in Australian food-webs, and, as study locations are situated on National parkland and conservation reserves, data are also contributing directly to local land management (e.g. by informing land managers of the potential impacts of carcasses left to lie in the environment following culling events).
Project updates as well as student and volunteer opportunities will be posted on this website, via my own twitter account (@NewsomeTM) and via the twitter account of Emma Spencer who is a PhD student on the project (@EE_Spencer).
Feel free to get in contact if you have any questions!
Check out the hungry lace monitor on the video link below:
Here is a pack of dingoes checking out one of the carcasses we are monitoring:
Wedge-tailed eagles are often the first to find and scavenge on the carcasses:
2017 has been an exciting year for my research.
Some highlights include:
- The scientists warning to humanity: a second notice (BioScience) was co-signed by 15,364 scientists from 184 countries, it is ranked as one of the most discussed papers ever tracked by Altmetric, and was read out in the BC Legislature.
- Making a new dog (BioScience) was selected as the Editor’s choice for the April Issue, and was featured in Science as well as the BioScience podcast series.
- Top predators constrain mesopredator distributions (Nature Communications) generated some media interest.
- I was involved in a plea to the Australian Government to “Save Australia’s ecological research“. For a summary see write ups in Science and Nature.
- Extinction risk is most acute for the world’s largest and smallest vertebrates (PNAS) generated mass media interest and some interesting discussions among scientists.
- Despite some grant knock-backs, securing several new grants for student led projects including from the Australian Pacific Science Foundation to study the ecological role of carcasses, and from the Threatened Species Recovery Hub to explore novel ways to conserve the endangered night parrot.
- The Red Kangaroo Book winning a Commendation Award from the Royal Zoological Society of New South Wales.
- And, thankfully, surviving the academic job market by securing an ongoing position as Lecturer (Academic Fellow) at The University of Sydney. I will commence in January 2018 after my Deakin University Fellowship has ended. Thank you Deakin for the support and great research environment over the last two years.
Last week, in collaboration with 68 scientists, I was co-author on a letter in Science titled “Save Australia’s Ecological Research”
The letter calls on the Federal Government to reverse its decision to cease funding Australia’s Long Term Ecological Research Network (LTERN). The network comprises more than 1100 long-term field plots across Australia, including those in the Simpson Desert (pictured above) where I have conducted research in collaboration with the Desert Ecology Research Group at The University of Sydney.
The letter has been featured in a news piece by John Pickrell in Science titled “Australia to ax support for long-term ecology sites“, as well as in a news piece by Nicky Phillips in Nature titled “Ecologists protest Australia’s plans to cut funding for environment-monitoring network”
The existing program receives $900,000 of support from the Federal Government’s Terrestrial Ecosystem Research Network (TERN). This support is being slashed at a time when even the USA is increasing funding for its own network by US$5.6M annually.
Hopefully a last ditch bid to the Federal Government by those who administer and lead LTERN will result in a reversal of this decision, and even better, an expansion of the program.
Richard (Dick) MacMillen (Professor Emeritus of Ecology and Evolutionary Biology, University of California, Irvine) recently reviewed our book “The Red Kangaroo in Central Australia; an early account by A.E. Newsome”.
The review was published in the May issue of Journal of Mammalogy.
A copy of the review is provided below:
“This gem of a book about Australia’s iconic symbol, the red kangaroo (Osphranter rufus; formerly Megaleia rufus, Macropus rufus; Jackson and Groves 2015), will serve as an inspiration to younger field-oriented mammalian ecologists and equally admired by more seasoned ones. It is a newly polished chronicle of an unfinished manuscript of pioneering field research conducted by Alan Newsome in Central Australia between 1957 and 1962, a region that then was still in a frontier state. The research took place when Alan was fresh out of the University of Queensland with just an undergraduate science degree. Alan had contracted with the Animal Industry Branch of the Northern Territory Government to learn all he could about the life history of the red kangaroo and its interactions with cattle in the arid interior of the Northern Territory, while other ecologists were conducting comparable studies in Western Australia, South Australia, and New South Wales.
It is unclear when Alan began drafting this manuscript, but the last dated correspondence with a potential publisher, Collins Publishing, was 1975. For reasons unknown, the manuscript was placed in storage at his home in Canberra, and was not refound until 2010, following Alan’s untimely death from Alzheimer’s disease in 2007. The manuscript and various notes and colored slides were discovered amongst his belongings by his wife Jane Thompson, and his son Thomas Newsome; Thomas is a promising young ecologist in his own right, with extensive field experience in the Northern Territory’s arid heart, and therefore all the more suited to see the manuscript through to publication. In so doing, Thomas sought faithfully to retain his father’s writing style, and transcribed the 6 manuscript chapters pretty much verbatim, even though they varied in their completeness from near final drafts to hand-scrawled notations.
From this has emerged a narrative description of a monumental 6-year ecological study in Central Australia, under the harshest of conditions of drought – summer daytime temperatures sometimes reaching 50 C – undertaken by a young man who, at its inception, was age 22. Provided with a four-wheel drive vehicle, access to a light airplane and pilot, a skilled rifle marksman, and indigenous aboriginal aids and informants, it still required a leader with exceptional organizational skills to design and execute the scale of study the goals demanded; that leader was the young Alan Newsome, who more than met those goals. In so doing, Alan established a study area in a vast region on the Burt Plain to the north of the MacDonnell Ranges that lie to the north and west of Alice Springs, N.T. The study area comprised 4 recognizable land-systems with discernible but overlapping plant components that lent themselves both to aerial surveys for kangaroo distribution and abundance, and ground-based collections for necropsy analysis of reproductive and physical condition; these studies spanned climatic events of prolonged drought finally broken by abundant rainfall over a region where, concomitantly, cattle grazed.
Repeated flights over fixed aerial transects during the study period revealed that these grass-dependent marsupials prefer to remain in the vicinity of mulga (Acacia aneura) woodlands, where their primary food, green grass, abounds in periods of normal rain; but, as drought ensues and these grasses dry up, there is a mass movement toward and into the open plains, where there are widely scattered seeps and springs which also attract cattle. There the cattle graze on the drying grass, which stimulates vegetative regrowth providing the kangaroos with a continuing supply of green food until the next rain cycle; then they will move back into the woodlands. Thus kangaroos, if anything, benefit from the presence of cattle during drought.
Between 1958 and 1963 a system of random ground sampling of red kangaroos was established at night along fixed transects in woodlands and open plains during and following drought, by spotlighting randomly selected animals from a vehicle; these were then shot to assess reproductive condition and physical state. About 2000 kangaroos were collected from which stomach samples and reproductive tracts were preserved for analysis. Stomach analyses confirmed that green grasses comprised the kangaroos’ diets, even during drought. Reproductively, female red kangaroos nearly always had a suckling joey either in the pouch or at foot, as well as an embryonic blastocyst in an arrested state of development (i.e. diapause) in the uterus; this latter condition was described earlier in detail in a small wallaby (the quakka) by Sharman (1954), and likely is characteristic of macropods in general. Continued development of the blastocyst occurs only following cessation of nursing of the preceding joey, either through weaning or death. Upon birth of a near-embryonic fetus, the mother kangaroo undergoes ovulation and postparturient mating, assuming a fertile male is present. Thus, even during severe drought resulting in a joey’s death, another replacement young is soon present to increase the probability of population survival. In a sense then, this macropod capacity of arrested development is a preadaptation for surviving drought, even though other circumstances may have stimulated its original evolution. In the males spermatogenesis resulting in fertility seemed to be unaffected by drought, except during the hottest, prolonged summer periods when some kangaroos in the open plains were without shelter, and unable to regulate testicular temperature compatible with sperm production; but even during these summer droughts at least some fertile males were always present, ensuring successful reproduction.
Alan also draws attention to the advantages during drought of the female kangaroo’s gestational characteristics compared to those of a cow, when both are competing for the same diminishing supply of grass. The kangaroo has a gestation period of only 5 weeks, yielding a tiny newborn weighing less than 1 g, and with minimal maternal investment other than that spent in milk production. In contrast, a pregnant cow has a gestation period of 9 months that yields a very large calf whose development has drawn heavily upon maternal bodily resources. If during drought, this may leave the cow in a severely depleted state, resulting in her death and then that of the milk-deprived calf. Thus this marsupial reproductive characteristic serendipitously favors success of the red kangaroo during drought.
Thomas Newsome has masterfully polished his father’s incomplete manuscript by adding appropriate photographs from Alan’s slide collection, maps scaled to geographic descriptions, and quantitative tables that document results and conclusions; these latter were derived largely from a series of articles Alan published between 1964 and 1973 (e.g., Newsome, 1971). Together, the authors provide an informative and provocative read about a truly remarkable mammal.
The final chapter (Ch. 7) is a reproduction of an article Alan published in the anthropological journal Mankind in 1980 that demonstrates the congruence of Aboriginal oral history (“mythology”) with Alan’s own intuitive and observational ecological conclusions concerning movement during drought of red kangaroos. During the course of his studies Alan was frequently in contact with Aboriginal people from the Aranda totemic group, whose mythological ancestor is Ara, the red kangaroo. Not only did Alan receive physical aid from some of these people, but they must also have shared bits of their ancestral mythology. In addition, Alan was greatly influenced by the writings of Ted Strehlow, a Central Australian anthropologist born and raised on an Aboriginal mission near Alan’s study area, and who spoke the Aranda dialect fluently. In particular, he was impacted by Strehlow’s book, Songs of Central Australia (1971), that included Aranda mythology about travels of the red kangaroo during drought between watering and feeding sites. According to Aboriginal legend, during non-drought conditions feeding and watering points were fairly readily available at sites along the northern base of the MacDonnell Ranges, and further out amongst the mulga woodlands; the kangaroos could readily travel overland between them. As drought ensued these watering points gradually dried up, forcing the kangaroos to travel progressively further out onto the open plains to find food and water at sites far distant from each other. This led to the mythological belief that the travel between such distant sites must have been through underground passages, enabling the kangaroos to avoid perhaps lethal surface conditions. Alan concluded that the mythological descriptions of many of these watering points matched where he had observed kangaroos feeding and drinking during and after drought, and that at least this part of Aboriginal mythology must be based upon a keen sense of ecological perception, enhancing Aboriginal access to their preferred protein source during demanding environmental circumstances.
In 1989, while on a research leave in Australia, my wife, son, and I had the great pleasure and privilege of accompanying Alan from Alice Springs around to the north slopes of the MacDonnell Ranges to see one of these totemic sites he had identified, and as described in Strehlow (1971); Alan felt comfortable in taking us there as all of the Aboriginal elders who had held the tribal secrets had passed on. It was a humbling experience to witness this congruity between Aboriginal mythology and ecological reality, particularly when, upon departing the site, a large red kangaroo crossed the track ahead of us. And, as Thomas Newsome so aptly states in his Preface to the book: “It remains a groundbreaking piece of work, a pioneering example of why ecologists and land managers alike should listen to, and learn from, Indigenous knowledge”.
I first met Alan at Adelaide University in 1966 during my initial sabbatical leave in Australia, while I was on a seminar junket from my host institution, Monash University near Melbourne. Alan, who was my junior by 3 years, immediately struck me as a warm, congenial and knowledgeable ecologist with whom I could readily become a close friend and colleague. Since then our paths had crossed many times, both during my numerous research leaves in Australia, and when he was our guest as Regents Professor of Ecology and Evolutionary Biology in my department at U.C. Irvine. During the latter period we interacted intensively both at professional and family levels. Although we never had the opportunity to collaborate directly in research, my work in Central Australia certainly was influenced by his many outstanding contributions. I have felt from the beginning, as I do today, that, in addition to a keen intellect, it was Alan’s ability to communicate with virtually anyone at his or her own level, whether it be a cattle station manager, an Aboriginal informant, a research colleague, a student, or a friend, that made him such a successful individual. These communication skills together with his high capacity for organization enabled him to complete successfully, even as a novice field ecologist, an enormous amount of important work. This book, then, should be read and appreciated as such and as a tribute to Alan Newsome, and it is appropriately dedicated to him by his son, Thomas. Alan, we miss you, Mate! DICK MACMILLEN, Professor Emeritus of Ecology and Evolutionary Biology, University of California, Irvine; 705 Foss Road, Talent, OR 97540, USA;
JACKSON, S, and C. GROVES. 2015. Taxonomy of Australian mammals. CSIRO Publishing, Collingwood, Australia.
NEWSOME, A.E. 1971. The ecology of red kangaroos. Australian Zoologist 16: 32-50.
NEWSOME, A.E. 1980. The eco-mythology of the Red Kangaroo in Central Australia. Mankind 12: 327-333.
SHARMAN, G.B. 1954. Reproduction in marsupials. Nature 173: 302-303;
STREHLOW, T.G.H. 1971. Songs of Central Australia. Angus & Robertson. Sydney, Australia.”
Thanks Dick for the kind review!
In a paper published last week in Nature Communications we explored relationships between top predators and lower order predators (mesopredators) across three separate continents. We found that top predators can suppress the abundances of mesopredators, but only when top predators occur at high densities over large areas. The results have important implications for understanding the ecological role of top predators, like dingoes and wolves, and for the conservation of ecosystems more broadly.
The results have been summarised in The Conversation.
See below for links to some of the media generated and for a copy of the abstract.
Reintroducing dingoes can help manage feral foxes and cats, study suggests (SMH)
Dingoes could be used to control fox numbers and prevent ecological decline (ABC)
Dingoes need more space to fight off pests, study finds (Australian Geographic)
Dingoes to the rescue? (Deakin University)
Wolves need space to roam to control expanding coyote population (University of Washington)
Study: to mitigate problem predators, give wolves more space, tolerance (KUOW)
Top predators can suppress mesopredators by killing them, competing for resources and instilling fear, but it is unclear how suppression of mesopredators varies with the distribution and abundance of top predators at large spatial scales and among different ecological contexts. We suggest that suppression of mesopredators will be strongest where top predators occur at high densities over large areas. These conditions are more likely to occur in the core than on the margins of top predator ranges. We propose the Enemy Constraint Hypothesis, which predicts weakened top-down effects on mesopredators towards the edge of top predators’ ranges. Using bounty data from North America, Europe and Australia we show that the effects of top predators on mesopredators increase from the margin towards the core of their ranges, as predicted. Continuing global contraction of top predator ranges could promote further release of mesopredator populations, altering ecosystem structure and contributing to biodiversity loss.