Many animals avoid contact with people. In protected areas of the African savanna, mammals flee more intensely upon hearing human conversations than when they hear lions or sounds associated with hunting. This fear of humans affects how species use and move in their habitat.
Throughout our lives, we interact with hundreds of wildlife species without stopping to think about it. These interactions can be direct, such as encountering wild animals while hiking in the mountains or driving through rural areas — or more deliberate, as when we engage with wildlife for food, sport, or trade. As hunters, fishers, and collectors, we kill more than 15,000 species of vertebrates — one-third of known diversity — a range of prey 300 times greater than that of any other predator our size (1).
Now, let’s look at it from the other side. Anyone who has survived an attack or a fatal accident, they understand that the experience is remembered for a lifetime. Likewise, animals store information about threatening or harmful encounters with humans (2). For them, adjusting their behaviour in response to human presence has implications for their survival and reproduction (3, 4), which are passed down from generation to generation (5). This ability to adapt, for example, determines which individuals, populations and species coexist with us in urbanised environments (6).
Response to dangerous sounds
Liana Zanette and her team measured the flight responses of wild mammals in the Greater Kruger National Park (South Africa) when exposed to sounds that signal danger (7) [video-summary]. To do this, Zanette recorded videos of more than 4,000 visits to 21 waterholes by 18 mammal species. During each visit, a speaker attached to a tree randomly played one of five playback sounds: hunting dogs barking, gunshots, lion growls, human conversations in a calm tone and, as a control, the songs of harmless birds.
Deep-sea sharks include some of the longest-lived vertebrates known. The record holder is the Greenland shark, with a recently estimated maximum age of nearly 400 years. Their slow life cycle makes them vulnerable to fisheries.
In the Arctic, there are whales that have survived since the time of Napoleon’s Empire; in the Atlantic, there are molluscs that were contemporary with Christopher Columbus’ voyages; and in Antarctica, there are sponges born before the Holocene when humans were still an insignificant species of hunter-gatherers (see video on lifespan variation in wildlife).
Long-lived species grow slowly and reproduce at later ages (1, 2). As a result, these animals require a long time to form abundant populations and to recover from fishing-related mortality.
Among cartilaginous fish (chimaeras, rays, sharks, and skates), the risk of extinction due to overfishing is twice as high for deep-sea species compared to coastal species, because the former have longer and slower life cycles (3).
Procreating with a relative is taboo in most human societies for many reasons, but they all stem from avoiding one thing in particular — inbreeding increases the risk of genetic disorders that can seriously compromise a child’s health, life prospects, and survival.
While we all inherit potentially harmful mutations from our parents, the effects of these mutations are often partially or completed masked if we possess two alternative variants of a gene — one from each parent. However, the children of closely related parents are more likely to inherit the same copies of harmful mutations. This is known as ‘inbreeding depression’.
But inbreeding depression can happen in any species, with the risk increasing as populations become smaller. Because many species are rapidly declining in abundance and becoming isolated from one another predominantly due to habitat destruction, invasive species, and climate change, the chances of inbreeding are also increasing.
Not only are such populations more susceptible to random disturbances, they are also victim of reduced population growth rates arising from inbreeding depression. This produces what is generally known as the ‘extinction vortex‘ — the smaller your population, the more you inbreed and produce sub-optimal offspring, leading to even more population decline and eventually extinction.
One emergency intervention that can ‘rescue’ such inbred populations from extinction (at least in the short term) is to introduce unrelated individuals from other populations in an attempt to increase genetic diversity, and therefore, the rate of population growth. While somewhat controversial because some fear introducing diseases or eroding local-area specialisation (so-called ‘outbreeding depression’), the risk-benefit ratio of this ‘genetic rescue’ is now widely considered to be worth it.
I used to think it was merely a post-COVID19 hiccough, but the extensive delays in receiving reviews for submitted manuscripts that I am seeing near constantly now are the symptoms of a much larger problem. That problem is, in a nutshell, how awfully journals are treating both authors and reviewers these days.
I regularly hear stories from editors handling my papers, as well as accounts from colleagues, about the ridiculous number of review requests they send with no response. It isn’t uncommon to hear that editors ask more than 50 people for a review (yes, you read that correctly), to no avail. Even when the submitting authors provide a list of potential reviewers, it doesn’t seem to help.
The ensuing delays in time to publication are really starting to hurt people, and the most common victims are early career researchers needing to build up their publication track records to secure grants and jobs. And the underhanded, dickhead tactic to reset the submission clock by calling a ‘major review’ a ‘rejection with opportunity to resubmit’ doesn’t fucking fool anyone. The ‘average time from submission to publication’ claimed by most journals is a boldface lie because of their surreptitious manipulation of handling statistics.
The most obese pachyderm in the room is, of course, the extortionary prices (and it is nothing short of extortion) charged for publishing in most academic journals these days. For example, I had to spend more than AU$17,000.00 to publish a single open-access paper in Nature Geoscience last year. That was just for one paper. Never again.
Anyone with even a vestigial understanding of economics feels utterly exploited when asked to review a paper for nothing. As far as I am aware, there isn’t a reputable journal out there that pays for peer reviews. As a whole, academics are up-to-fucking-here with this arrangement, so it should come as no surprise that editors are struggling to find reviewers.
In boreal forests, many hares adopt white winter coats before the snow arrives. In a snowless landscape, these white hares lack camouflage against predators. However, their early moult from brown into white fur can increase their survival and offers an advantage as the snow season becomes progressively shorter with climate change.
Throughout the year, we wear different clothing to protect ourselves from the cold or heat and for aesthetic reasons depending on the occasion. Likewise, many animals change the colour, thickness and structure of their fur and feathers in tune with the seasons.
Snowshoe hare (Lepus americanus) in a snowy (Kluane Lake/Yukon, Canada) and snowless habitat (Seely Lake/Montana, USA). This mammal moults its coat as colder temperatures, shorter days, and snowfall arrive. In the genetic populations of the temperate forests of the Rocky Mountains and the boreal forests spanning the North American continent, hares that moult from brown to white are abundant (20). However, in coastal areas, and in the third genetic population in the North Pacific, snowfall is brief and less intense, resulting in fewer white individuals. This is due to hybridisation with the black-tailed jackrabbit (Lepus californicus) over 3,000 years ago (17). The hare’s coat has an outer layer, where the longer fur gives each individual its colour, and an inner layer of short fur (19). In winter, the outer layer becomes thicker and denser, while the inner layer maintains a consistent thickness but increases in density. By biomass, the snowshoe hare is the primary herbivore in the North American boreal forest and distinguishes the trophic relationships between continents (21). In Europe, much of the boreal understory remains under snow, providing food for rodents with four-year abundance cycles controlled by small generalist predators (mustelids). In North America, the boreal understory grows above the snow and provides food for hares. In this region, snowshoe hare populations follow 10-year abundance cycles regulated by specialist predators (those that feed almost exclusively on hares), primarily the Canada lynx (Lynx canadensis) (6). Photos courtesy of Alice Kenney and Charles Krebs (Yukon) [see their ecological monitoring program here] and Marketa Zimova (Montana).
However, as the climate changes, springs arrive earlier, winters are delayed, and the frequency and intensity of precipitation have become highly variable. All of this makes it harder for species to adjust their wardrobe to temperature changes (1).
In this context, body colour is a critical factor for birds and mammals that undergo an annual moult (2). In 21 species from the cold latitudes of the Northern Hemisphere, some individuals are brown in summer, but turn white in winter, while others remain brown year round (3). This phenomenon includes weasels, rodents, ptarmigans, foxes, rabbits and hares.
Coral reefs are much more than just a pretty place to visit. They are among the world’s richest ecosystems, hosting about a third of all marine species.
These reefs also directly benefit more than a billion people, providing livelihoods and food security, as well as protection from storms and coastal erosion.
Without coral reefs, the world would be a much poorer place. So when corals die or become damaged, many people try to restore them. But the enormity of the task is growing as the climate keeps warming.
In our new research, we examined the full extent of existing coral restoration projects worldwide. We looked at what drives their success or failure, and how much it would actually cost to restore what’s already been lost. Restoring the reefs we’ve already lost around the world could cost up to A$26 trillion.
Bleached Acropora corals in the Maldives.Davide Seveso/University of Milan
When sea temperatures climb above the seasonal average for sustained periods, corals can become bleached. They lose colour as they expel their symbiotic algae when stressed, revealing the white skeleton underneath. Severe bleaching can kill coral.
Night is the peak activity period for many animal species. In the Western Andes of Ecuador, the Chocó golden scarab flies between forest patches during the night, but urban lighting interferes with their paths and jeopardises populations already struggling to persist in fragmented native forests.
Urban development has created a network of illuminated infrastructure that allows our society to function day and night without interruption. It is no surprise that with so much artificial light, we increasingly have to move farther away from towns and cities to see a sky full of stars.
Light pollution poses a challenge for nocturnal species that have adapted to living in the dimness of night (1, 2) — see documentaries about the impacts of artificial light on wildlife and insects, and a related scientific talk. This problem might be one of the causes of the global decline in insects (3, 4), in turn negatively affecting their role in maintaining agricultural systems through pest control, pollination, and soil quality (5). These concepts are featured by the documentaries The Insect Apocalypse and The Great Death of Insects.
Chocó golden scarab (Chrysina argenteola) walking on forest litter in La Maná (Cotopaxi, Ecuador). Growing to up to 4 cm in length, this species inhabits the tropical rainforest of the Chocó region in the Western Andes (10), where it is frequently attracted to artificial lights at night. The striking colour of this ‘jewel scarab’ is an optical illusion. The exoskeleton is covered with overlapping layers of chitin that polarise light and reflect hues of blue, gold, green, silver, or reddish tones, depending on the species (16). The metallic sheen appears to deter bird predation (17) and might serve as camouflage as well as aid in individual recognition (11). The eyes of insects are ‘compound’ — composed of 100s to 1000s of tubular eyelets (‘ommatidia’), each with its own cornea and lens (18), and all collectively contributing to insect vision. In nocturnal species like the golden scarab, the photoreceptor cells (at the base of each ommatidium) respond more slowly to light compared to diurnal species, allowing the former to collect more nocturnal light per unit of time before forming an image (19). However, just as staring at the sun blinds us, eyes adapted for night vision become overwhelmed by excessive artificial light, disrupting the behaviour of these species. Below the scarab image are two photographs contrasting the day and night landscapes of the same location in Pedro Vicente Maldonado (Pichincha, Ecuador) within the species’ distribution range. Photos courtesy of Martín Bustamante (animal) and Luis Camacho (city).
When flying, nocturnal insects orient their backs toward the sky, using the light of the moon and stars as a reference (6) (explained here and here). However, when they encounter artificial lights, they can no longer distinguish up from down, and so they can become disoriented, flying erratically, like a moth circling a streetlight.
It is estimated that a third of the insects attracted to artificial light die from collisions, burn injuries, exhaustion, and/or predation (7). In the tropics, finding countless dead insects at the base of urban lights is a common scene. Equally important is that artificial light also hinders migration, foraging, and the search for mates in many nocturnal species (1, 8, 9).
Nocturnal jewels
Camacho and collaborators evaluated the effect of artificial lighting at night on the Chocó golden scarab (Chrysina argenteola) (10). This species inhabits the tropical rainforests of the Western Andes from Ecuador to Colombia, and is a member of the group known as ‘jewel scarabs‘ due to their metallic body coloration (11). Because of its nocturnal habits and the larvae’s dependence on wood for food (12), the golden scarab has been increasingly affected by the loss of native forest in combination with light pollution from rural and urban expansion.
Yes, it’s bad, especially for US-based scientists. It also affects scientists in Australia and the rest of the world. But there are ways to get around the problem. There might even be a silver lining to this dark cloud.
Trump cannot stop global climate action, although he might slow it. Nor can he hide the truth by restricting access to data. Climate research will continue despite Trump’s best efforts to hamstring scientists and research institutions.
No strength in ignorance
Last year was the warmest on record, a fact that yet again confirms our worst-case predictions. The world has already surpassed the (arbitrary) 1.5°C threshold increase relative to pre-industrial temperatures — a threshold that only a few years ago we didn’t think we would cross until 2030 at the earliest.
We’re now on track to be living in a world that’s 3°C hotter or more by the end of the century.
But ignoring climate change won’t make it go away. Like the Ministry of Truth in George Orwell’s classic dystopian novel, 1984, Trump seems to believe “ignorance is strength”. He’s trying to erase facts about the climate crisis, perhaps to keep people ignorant and subdued.
What this means for Australian climate science
Many Australian scientists (including me) collaborate regularly with US colleagues, share funding, and publish results together. Knowledge sharing and open-access data are the foundation of advances in science, so Trump’s assault will inevitably slow progress here.
For example, Australian and US scientists regularly collaborate in big-ticket research and policy development related to climate change, such as the Intergovernmental Panel on Climate Change’s Physical Science Basis reports. But even with fewer US scientists in the mix, the research and reporting will continue.
Other reputable climate-data repositories around the world include the European Union’s Climate Data Store, the University of East Anglia’s Climate Research Unit, the Netherlands Meteorological Institute’s Climate Explorer, and the independent WorldClim, to name a few.
While restricting access to US-based websites is inconvenient, we can readily get around the problem. Many of my colleagues have also been downloading data prior to the purge mandate to maintain access.
Consequences for the US
Over the past month I have been inundated with horror stories from many US-based colleagues in academia and the public service, who have lost their jobs and/or research funding. In addition to these very real personal tragedies, the bigger picture is even bleaker.
The loss of scientific and technical expertise these mass sackings entail weakens the capability of the US workforce to discover and develop solutions to climate change. Just when we need good scientific and engineering innovations more than ever, a massive capacity is being erased before our eyes.
More emissions mean more climate change, especially when you’re already one of the biggest contributors to the global problem. The US is the second-highest greenhouse emitter in the world, behind only China.
On his first day as president, Trump withdrew the US from the Paris climate agreement. This effectively removes his country from all binding limits on actions that contribute to climate change.
Weakening international treaties is a two-edged sword, because it not only lets the US off the leash, it also potentially discourages other nations from acting responsibly. Analogous to the “unresponsive bystander effect”, many nations may now be more hesitant to commit to reductions because one of the biggest emitters refuses to do anything about it.
Trump has also slashed US international aid, which will slow climate action in countries that need the most assistance.
Overall, faster rates of warming will inevitably put more strain on natural resources and agricultural production. This could increase the probability of international warfare over water, food and other essential natural resources. Because autocratic countries cope worse with food shortages than democratic ones, climate emergencies will penalise nations led by despots more heavily.
Trump’s foolhardy anti-climate campaign is enough to make many people despair. But there are a few faint glimmers of hope on the horizon.
As the US shirks its domestic and international responsibilities, other countries might resolve to do more. Not relying on the US could force capacity-building elsewhere. Some even suggest without the US at the table slowing progress, stronger climate action might result.
Americans have their own daunting fight on their hands. But the rest of the world will have to take up the slack if we have any chance of limiting the health, wealth, equality, human rights and biodiversity calamities now unfolding because of climate change.
Corey J. A. Bradshaw, Matthew Flinders Professor of Global Ecology and Node Leader in the ARC Centre of Excellence for Indigenous and Environmental Histories and Futures, Flinders University
This is a fixed-term position for up to 3 years, and we are especially targeting Indigenous candidates.
The successful candidate will use existing code and develop new approaches to analyse complex data derived from lake, lagoon, river, and wetland cores measuring various aspects of dated vegetation composition, fire regime, and climate fluctuation. Additionally, the successful candidate will design simulation models to evaluate how different proxies behave under various environmental conditions, aiding in the interpretation of outputs from time-series models.
As a position under CIEHF, the position requires co-designing projects with Indigenous Partner Organisations, as well as extensive travel to the other Nodes within CIEHF to collaborate with palaeo-ecologists, climatologists, archaeologists, and other relevant specialists.
For more information and details on the application process, visit this link.
The internet has become an informational telescope to study what happens nearly everywhere the planet. Using internet observations, it has been recently documented that terrestrial hermit crabs use plastic waste as shelter along tropical coasts.
Before the internet irrupted, I was living in Spain and frequently travelled from my hometown to universities in Valencia and Barcelona to access scientific journals. Back then, these journals were only available in print or on compact discs. Today, I can do the same thing from home with an internet connection.
The emergence of public internet since the 1990s has globalised information and represents a data source for many areas of science (1, 2). When applied to nature, the term iEcology (internet Ecology) refers to the use of online documentation to study the natural history of plants and animals, their distributions, and the effects of humans on them (3). In fact, the internet highlights and promotes certain research topics. For example, bird species that are more frequently mentioned on social networks tend to be described taxonomically earlier, and are also the ones that interact most (positively or negatively) with human activity (4).
In search of the phenomenon
By exploring internet platforms Alamy, Flickr, Google, YouTube, and iNaturalist, Zuzanna Jagiello and her collaborators collected nearly 30 thousand photographs of hermit crabs to study the use of rubbish by these crustaceans (5). Hermit crabs are known for their peculiar habit of using empty snail shells to house their unprotected abdomens, carrying them around like someone travelling with their house on their back (6) — David Attenborough narrates here a funny swapping of shells among crabs of different size. The researchers aimed to assess the extent of the phenomenon of hermit crabs replacing natural shells with artificial materials as mobile homes (see video capturing the scene).
If you’re like me, you use a lot of loops in R. I do not profess to be the most efficient coder, but loops make sense to me and I’m generally not concerned about make the fastest simulations.
But sometimes my loops take some time to finish, so I often add a rolling text update during the simulation to know how far it has progressed. But of course, I have to look at the R console to see how far things have come. Being a bit away from the central tendency of the spectrum, I can get absorbed in doing other things, so I often miss when the simulation is complete.
In a fit of excess geekiness, I’ve recently discovered voice prompts in MacOS that I can now code directly into my R simulations to give verbal updates on their progress. I find these immensely useful. I’ve therefore decided to share the basic code, because I know some other geeks out there might also appreciate the tool. Apologies — I haven’t investigated how to do this in a PC environment, so the following examples are MacOS-specific.
First, go to your Accessibility settings in System Settings in your Mac. Click on System Voice to see what voices you have access to, and which voices you wish to download to your machine. There are many languages supported.
When you construct a loop in R, add the following code within and before the loop content (this example is in English):
iter <- 1000 # number of iterations
itdiv <- iter/100 # iteration divisor 1
itdiv2 <- iter/10 # iteration divisor 2
st.time <- Sys.time() # time at start of simulation
# loop from 1 to iter
for (i in 1:iter) {
# pause execution for 0.05 seconds (this would normally be the guts of your loop functions)
Sys.sleep(0.05)
# loop updaters with voice (English)
if (i %% itdiv==0) print(paste("iter = ", i, sep=""))
if (i %% itdiv2==0 & i < iter) system2("say", c("-v", "Fiona", paste(round(100*(i/iter), 0),
"per cent complete"))) # updates every 10% complete
if (i == 0.95*iter) system2("say", c("-v", "Fiona", paste(round(100*(i/iter), 0),
"per cent complete"))) # announce at 95% complete
if (i == 0.99*iter) system2("say", c("-v", "Fiona", paste(round(100*(i/iter), 0),
"per cent complete"))) # announce at 99% complete
if (i == iter) system2("say", c("-v", "Lee", "simulation complete"))
if (i == iter) system2("say", c("-v", "Lee", paste(round(as.numeric(Sys.time() - st.time,
units = "mins"), 2), "minutes elapsed")))
}
Here I’ve used the female Scottish voice ‘Fiona’ and the male Australian voice ‘Lee’.
Quite a bit late this year, but I’ve finally put together the 2023 conservation / ecology / sustainability journal ranks based on my (published) journal-ranking method (as I’ve done every year since 2008).
After 16 years of doing this exercise, I can’t help but notice that most journals don’t do much differently from year to year. They mostly tend to publish the same number of papers, get the same number of total publications, and therefore, remain approximately in the same rank relative to others.
Some things to note: Clarivate continues to modify its algorithm, meaning that most journal Impact Factors have gone down yet again. This is somewhat irrelevant from the perspective of relative ranking, but it might piss off a few journals.
I therefore present the new 2023 ranks for: (i) 111 ecology, conservation and multidisciplinary journals, (ii) 29 open-access (i.e., you have to pay) journals from the previous category, (iii) 68 ‘ecology’ journals, (iv) 33 ‘conservation’ journals, (v) 44 ‘sustainability’ journals (with general and energy-focussed journals included), and (vi) 21 ‘marine & freshwater’ journals.
The Black Summer bushfires of 2019–2020 that razed more than half of the landscape on Kangaroo Island in South Australia left an indelible mark on the island’s unique native biodiversity, which is still struggling to recover.
Flinders Chase National Park on Kangaroo Island after the 2019-2020 Black Summer fires (credit: CJA Bradshaw)
However, one big bonus for the environment’s recovery is the likely eradication of feral pigs (Sus scrofa). Invasive feral pigs cause a wide range of environmental, economic and social damages. In Australia, feral pigs occupy about 40% of the mainland and offshore islands, with a total, yet highly uncertain, population size estimated in the millions.
Feral pigs are recognised as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999, with impacts on at least 148 nationally threatened species and eight threatened ecological communities. They are a declared invasive species and the subject to control programs in all Australian jurisdictions.
Motion sensing cameras deployed during the eradication program capture feral pigs using their snouts to search for soil-borne food. This behaviour, called rooting, creates large areas of disturbed soil, killing native vegetation and spreading invasive weeds and pathogens (credit: PIRSA).
Imagine growing up beside the eastern Mediterranean Sea 14,000 years ago. You’re an accomplished sailor of the small watercraft you and your fellow villagers make, and you live off both the sea and the land.
But times have been difficult — there just isn’t the same amount of game or fish around as when you were a child. Maybe it’s time to look elsewhere for food.
Now imagine going farther than ever before in your little boat, accompanied maybe by a few others, when suddenly you spot something on the horizon. Is that an island?
The western coast of Cyprus. CJA Bradshaw / Flinders University
When you beach your boat to have a look around, you can’t believe what you’re seeing — tiny boar-sized hippos and horse-sized elephants that look like babies to your eyes. There are so many of them, and you’re hungry after the long journey.
The diminutive beasts don’t seem to show any fear. You easily kill a few and preserve the meat as best you can for the long journey back.
When you get home, you are excited to let everyone in the village know what you’ve found. Soon enough, you organise a major expedition back to the island.
Of course, we’ll never know if this kind of scenario took place, but it’s a plausible story of how and when the first humans managed to get to Cyprus. It also illustrates how they might have quickly brought about the demise of the tiny hippopotamusPhanourios minor, as well as the dwarf elephantPalaeoloxodon cypriotes.
Human overpopulation is often depicted in the media in one of two ways: as either a catastrophic disaster or an overly-exaggerated concern. Yet the data understood by scientists and researchers is clear. So what is the actual state of our overshoot, and, despite our growing numbers, are we already seeing the signs that the sixth mass extinction is underway?
In a recent episode of The Great Simplification podcast, Nate Hagens was joined by global ecologist Corey Bradshaw to discuss his recent research on the rapid decline in biodiversity, how population and demographics will change in the coming decades, and what both of these will mean for complex global economies currently reliant on a stable environment.
Non-native species introduced mainly via increasing trade of goods and services have huge economic, health, and environmental costs. These ‘biological invasions’ involve the intentional or unintentional transport and release of species beyond their native biogeographical ranges, facilitating their potential spread.
However, there is limited information available demonstrating whether a country’s capacity to manage its invasive species is effective at limiting future damage.
Our new study published in the journal Ecological Economics found that while more affluent countries with higher economic activity are vulnerable to more damage from invasive species, they also have the highest potential to limit damages incurred by investing more in management. Consequently, a nation’s economic capability partially determines the efficacy of investing in the control and prevention of invasive species.
In Australia, most fire occurs in the vast tropical savannas of the country’s north. In new research published in Nature Geoscience, we show Indigenous management of fire in these regions began at least 11,000 years ago – and possibly as long as 40,000 years ago.
But climate change and other effects of human activity are making wildfires more common and more severe in many regions, often with catastrophic results. In Australia, fires have caused major economic, environmental and personal losses, most recently in the south of the country.
Australia is home to about one in 12 of the world’s species of animals, birds, plants and insects – between 600,000 and 700,000 species. More than 80% of Australian plants and mammals and just under 50% of our birds are found nowhere else.
But habitat destruction, climate change, and invasive species are wreaking havoc on Earth’s rich biodiversity, and Australia is no exception.
More and more species stand on the edge of oblivion. That’s just the ones we know enough about to list formally as threatened. Many more are in trouble, especially in the oceans. Change is the new constant. As the world heats up and ecosystems warp, new combinations of species can emerge without an evolutionary connection, creating novel communities.
It is still possible to stop species from dying out. But it will take an unprecedented effort.
The vulnerable southern bell (growling grass) frog (Litoria raniformis). Rupert Mathwin/Flinders University
For much of the 65,000 years of Australia’s human history, the now-submerged northwest continental shelf connected the Kimberley and western Arnhem Land. This vast, habitable realm covered nearly 390,000 square kilometres, an area one-and-a-half times larger than New Zealand is today.
Left: Satellite image of the submerged northwest shelf region. Right: Drowned landscape map of the study area. US Geological Survey, Geoscience Australia
It was likely a single cultural zone, with similarities in ground stone-axe technology, styles of rock art, and languages found by archaeologists in the Kimberley and Arnhem Land.
There is plenty of archaeological evidence humans once lived on continental shelves – areas that are now submerged – all around the world. Such hard evidence has been retrieved from underwater sites in the North Sea, Baltic Sea and Mediterranean Sea, and along the coasts of North and South America, South Africa and Australia.
In a newly published study in Quaternary Science Reviews, we reveal details of the complex landscape that existed on the Northwest Shelf of Australia. It was unlike any landscape found on our continent today.
A continental split
Around 18,000 years ago, the last ice age ended. Subsequent warming caused sea levels to rise and drown huge areas of the world’s continents. This process split the supercontinent of Sahul into New Guinea and Australia, and cut Tasmania off from the mainland.
Unlike in the rest of the world, the now-drowned continental shelves of Australia were thought to be environmentally unproductive and little used by First Nations peoples.
But mounting archaeological evidence shows this assumption is incorrect. Many large islands off Australia’s coast – islands that once formed part of the continental shelves – show signs of occupation before sea levels rose.
Stone tools have also recently been found on the sea floor off the coast of the Pilbara region of Western Australia.
Many animals avoid contact with people. In protected areas of the African savanna, mammals flee more intensely upon hearing human conversations than when they hear lions or sounds associated with hunting. This fear of humans affects how species use and move in their habitat. Throughout our lives, we interact with hundreds of wildlife species without…
Deep-sea sharks include some of the longest-lived vertebrates known. The record holder is the Greenland shark, with a recently estimated maximum age of nearly 400 years. Their slow life cycle makes them vulnerable to fisheries. Humans rarely live longer than 100 years. But many other animals and plants can live for several centuries or even millennia, particularly…
Procreating with a relative is taboo in most human societies for many reasons, but they all stem from avoiding one thing in particular — inbreeding increases the risk of genetic disorders that can seriously compromise a child’s health, life prospects, and survival. While we all inherit potentially harmful mutations from our parents, the effects of…
ConservationBytes.com 