We have discovered a new species of orangutan – the third known species and the first new great ape to be described since the bonobo almost a century ago.
The new species, called the Tapanuli orangutan (Pongo tapanuliensis), has a smaller skull than the existing Bornean and Sumatran orangutans, but has larger canines.
As we and our colleagues report in the journal Current Biology, the new species is represented by an isolated population of fewer than 800 orangutans living at Batang Toru in northern Sumatra, Indonesia.
The existence of a group of orangutans in this region was first reported back in 1939. But the Batang Toru orangutans were not rediscovered until 1997, and then confirmed in 2003. We set about carrying out further research to see whether this isolated group of orangutans was truly a unique species.
On the basis of genetic evidence, we have concluded that they are indeed distinct from both the other two known species of orangutan: Pongo abelii from further north in Sumatra, and Pongo pygmaeus from Borneo.
The Batang Toru orangutans have a curious mix of features. Mature males have cheek flanges similar to those of Bornean orangutans, but their slender build is more akin to Sumatran orangutans.
The hair colour is more cinnamon than the Bornean species, and the Batang Toru population also makes longer calls than other orangutans.
To make completely sure, we needed more accurate comparisons of their body dimensions, or “morphology”. It was not until 2013 that the skeleton of an adult male became available, but since then one of us (Anton) has amassed some 500 skulls of the other two species, collected from 21 institutions, to allow for accurate comparisons.
Analyses have to be conducted at a similar developmental stage on male orangutan skulls, because they continue growing even when adult. Anton found 33 skulls of wild males that were suitable for comparison. Of 39 different measurement characteristics for the Batang Toru skull, 24 of them fall outside of the typical ranges of northern Sumatran and Bornean orangutans.
Overall the Batang Toru male has a smaller skull, but bigger canines. Combining the genetic, vocal, and morphological sources of evidence, we have confidently concluded that Batang Toru orangutan population is a newly discovered species – and one whose future is already under threat.
Despite the heavy exploitation of the surrounding areas (hunting, habitat
alteration and other illegal activities), the communities surrounding the habitat of the Tapanuli orangutan still give us the opportunity to see and census the surviving population. Unfortunately, we believe that the population is fewer than 800 individuals.
Of the habitat itself, no more than 10 square km remains. Future development has been planned for that area, and about 15% of the orangutans’ habitat has non-protected forest status.
The discovery of the third orangutan in the 21st century gives us an understanding that the great apes have more diversity than we know, making it all the more important to conserve these various groups.
Without the strong support of, and participation from, the communities surrounding its habitat, the future of the Tapanuli orangutan will be uncertain. Government, researchers and conservation institutions must make a strong collaborative effort to make sure that this third orangutan will survive long after its discovery.
Native species are particularly vulnerable on islands, because when invaders such as rats arrive, the native species have nowhere else to go and may lack the ability to fend them off.
The main characteristic of an island is its isolation. Whether just off the coast or hundreds of kilometres from the nearest land, they stand on their own. Because of their isolation, islands generally have a unique array of plant and animal species, many of which are found nowhere else. And that makes all islands one of a kind.
However, islands, despite being geographically isolated, are now part of a network. They are globally connected to the outside world by planes, boats and people. Their isolation has been breached, offering a pathway for introduced species to invade.
The Galapagos Islands, 1,000km off the coast of Ecuador, provide a great example. So far, 1,579 introduced species have been documented on the Galapagos Islands, of which 98% arrived with humans, either intentionally or accidentally.
More than 70% of these species have arrived since the 1970s – when Galapagos first became a tourist destination – an average of 27 introduced species per year for the past 40 years.
Introduced species – plants or animals that have been artificially brought to a new location, often by humans – can damage native fauna and flora. They are among the top threats to biodiversity worldwide, and one of the most important threats to oceanic islands. The Convention on Biological Diversity has a dedicated target to help deal with them and their means of arrival. The target states that:
by 2020, invasive alien species and pathways are identified and prioritised, priority species are controlled or eradicated and measures are in place to manage pathways to prevent their introduction and establishment.
The Galapagos Islands are home to giant tortoises, flightless cormorants, and the iconic Darwin’s finches – species that have evolved in isolation and according to the differing characteristics of each of the islands.
However, the Galapagos’ natural attributes have also made these islands a top tourist destination. Ironically enough, this threatens the survival of many of the species that make this place so unique.
Humans on the rise
In 1950 the Galapagos Islands had just 1,346 residents, and no tourists. In 2015 more than 220,000 visitors travelled to the islands. These tourists, along with the 25,000 local residents, need to have most of their food and other goods shipped from mainland Ecuador.
These strengthening links between Galapagos and the mainland have opened up pathways for the arrival and spread of introduced species to the archipelago, and between its various islands.
Plants were the most common type of introduced species, followed by insects. The most common pathway for species introduction unintentionally was as a contaminant on plants. A few vertebrates have also been recorded as stowaways in transport vehicles, including snakes and opossums; whilst others have been deliberately introduced in the last decade (such as Tilapia, dog breeds and goldfishes).
The number, frequency and geographic origin of alien invasion pathways to Galapagos have increased through time. Our research shows a tight relationship between the number of pathways and the ongoing increase in human population in Galapagos, from both residents and tourists.
For instance, the number of flights has increased from 74 flights a week in 2010 to 107 in 2015; the number of airplane passengers has also increased through time with about 40% being tourists, the remainder being Galapagos residents or transient workers.
Global connections between Galapagos and the outside world have also increased, receiving visitors from 93 countries in 2010 to 158 in 2014. In 2015 and 2016, the Galapagos Biosecurity Agency intercepted more than 14,000 banned items, almost 70% of which were brought in by tourists.
We think it likely that intentional introductions of alien species will decline when biosecurity is strengthened. However, with tourists as known vectors for introduced species and with tourism much the largest and fastest growing sector of the local economy, unintentional introductions to Galapagos will almost certainly increase further.
If islands are to be kept as islands, isolated in the full sense of the word, it is of high priority to manage their invasion pathways. Our research aims to provide technical input to local decision makers, managers and conservation bodies working in Galapagos in order to minimise a further increase on the number of available pathways to Galapagos and the probable likelihood of new arrivals. Our next step is to evaluate how local tourism boats are connecting the once isolated islands within Galapagos, as a way to minimise further spread of harmful introduced species to this UNESCO World Heritage Site.
Earlier this month, Australia’s outgoing Threatened Species Commissioner Gregory Andrews told ABC radio that land clearing is not the biggest threat to Australia’s wildlife. His claim caused a stir among Australia’s biodiversity scientists and conservation professionals, who have plenty of evidence to the contrary.
The ecologist Jared Diamond has described an “evil quartet” of threatening processes that drive species to extinction: habitat destruction; overhunting (or overexploitation); the presence of introduced species; and chains of linked ecological changes, including co-extinctions.
So the evil quartet has now become an evil sextet. It sounds ugly because it is. But does habitat loss through land clearing still top the list? The answer, in short, is yes.
Land clearing threat
According to an analysis of data from the International Union for the Conservation of Nature (IUCN), habitat loss is the number-one threat to biodiversity worldwide. Many more species are affected by processes such as logging and land clearing for agriculture and housing than by invasive species, disease or other threats.
But despite this, habitat loss and land clearing pose an even bigger threat to animals and plants alike. It is the single biggest factor adding to Australia’s list of threatened species list, especially given the recent return to record-breaking land clearing rates.
Of course, the evil sextet do not operate independently; they gang up, often with devastating results. The joint impact of two threats is often larger than the sum of its parts. Habitat destruction is the gang leader that joins forces with other threats to accelerate the slide to extinction.
When habitats are intact, large and in good condition, the species that depend on them are much better equipped to withstand other threats such as bushfires or invasive species. But as habitat is destroyed and chopped into smaller fragments, species’ populations become smaller, more isolated, and more vulnerable to predation or competition.
Larger populations of animals and plants also generally have larger gene pools, making them more able to adapt to new threats before it’s too late. Small populations, on the other hand, are sitting ducks.
You can see where this is heading. It’s all about habitat loss, because habitat loss makes all other threats more acute.
The political landscape
Habitat loss is a polarising political issue, which makes it hard to legislate against. Most habitat is lost through land clearing for agriculture and urban development.
The quality and effectiveness of land clearing policy and legislation in Australia has risen and fallen like the tide over the past four decades. After being the world’s largest land clearing jurisdiction behind Brazil in the post-war era, the Beattie government in Queensland introduced hugely improved land-clearing laws in the mid-1990s.
But under the Newman government, Queensland resumed its world leadership in habitat destruction. While Queensland may be the most extreme example, every Australian state and territory has witnessed similar policy uncertainty over the decades. Meanwhile, no federal environment minister has made significant inroads into the problem since the establishment of the 1999 Environment Protection and Biodiversity Conservation Act.
Of course, the outgoing Threatened Species Commissioner is right to acknowledge the impact that feral cats and foxes. But I hope that whoever next takes on the role will be prepared to deliver an unambiguous message about the biggest threat to our plants and animals, and to outline a strong vision for how we can address it.
If more sightings of an endangered species are recorded, does that mean its numbers are increasing? Australia’s native forest logging industry is arguing yes.
On the basis of an increase in sightings of Leadbeater’s possums, advocates for Victorian native forest logging industry has proposed to downgrade the possum’s conservation status from critically endangered (thus facilitating ongoing logging in and around potential habitat in Victoria’s Central Highlands).
But while this sounds reasonable, increased sightings aren’t always a reliable measure of endangered species’ viability. Often, an increase in sightings can be attributed to two things: either more people are trying to spot the animal in question; or new work that has used different parameters to previous studies.
One of the ultimate achievements in successful conservation is to downlist a threatened species – for example from critically endangered to endangered, or from endangered to vulnerable. But this requires high-quality, long-term survey data that shows substantial recovery, as well as proof that the key threats to a species’ persistence have been truly mitigated.
An example of a failure to do due diligence was the woylie in Western Australia, (also known as the brush-tailed bettong). It was downlisted in 1996 but then within 3 years suffered an enormous and still not well understood population crash (from which it has still not recovered). Its conservation status was uplisted in 2008.
There have been more records of Leadbeater’s possum in the last few years, but this growth is most likely a function of a large increase in the amount of effort invested in trying to find them.
In areas zoned for timber harvesting, locations with a confirmed Leadbeater’s possum sighting are excluded from logging. This has motivated large numbers of people who are concerned about the plight of the possum to devote many hours to finding animals.
The detection of more animals with greater searching is a well-known phenomenon in ecology and other disciplines. Last year, for example, sightings of wild tiger populations rose by 22% – but further investigation found that the increase was most likely caused by changes in methodology and greater effort in surveying.
In fisheries this relationship is termed catch per unit effort. For example, even with rapidly declining numbers in a fishery, the number of fish caught can stay the same or even go up when more efficient and targeted techniques are adopted. Sadly, this intensified effort can often cause fish stocks to collapse.
The real evidence on Leadbeater’s possum
As stated earlier, the first critical piece of evidence required to justify downlisting is robust evidence of long-term improvement in population size. So what does the evidence tell us about Leadbeater’s possum?
For more than 34 years, the Australian National University has monitored Leadbeater’s possum including at more than 160 permanent sites since 1997. This large-scale, long-term data set shows that the possum is in significant decline. Over the past 19 years, the number of survey sites where the possum was detected has dropped by almost two-thirds.
The second critical requirement for delisting is evidence that the key processes threatening the species have been mitigated.
One of the principal threats facing Leadbeater’s possum is the rapid ongoing decline in large old trees which are the sole form of natural nesting sites for the species.
As part of ecological surveys in the wet forests of Victoria, which have been running since 1983, the Australian National University has been collecting information on hollow-bearing trees. The most recent analysis of this large and long-term data set suggests that if current declines continue, by 2040, populations of large old trees may be less than 10% of what they were in 1997.
Efforts to downlist Leadbeater’s possum are misguided at best. The greater number of records in recent years is most likely a reflection of greater survey effort. In contrast, robust long-term monitoring data clearly shows a significant decline in population.
Most importantly, the key processes causing the decline of Leadbeater’s possum (and other threatened species in the same area, like the greater glider) have not been mitigated; indeed they are intensifying (such as the increasing fire burden with increasing area of logged forest).
There is little room to gamble with these species. Leadbeater’s possum and the greater glider currently do not breed in captivity, so expensive fallback options like captive breeding and reintroduction are not viable possibilities if wild populations crash.
The loss of these animals from ill-informed downlisting would add to Australia’s already appalling record on species loss. Approximately 10% of our mammal fauna has gone extinct – the worst rate in the world, and 30 times worse than places of equivalent size, such as the United States.
Furore erupted last week among many Australians who care for our native species.
First we heard that land clearing in Queensland soared to a staggering 400,000 or so hectares in 2015-16, a near 30% increase from the previous year. Second, the federal government’s outgoing Threatened Species Commissioner, Gregory Andrews, implied on national radio that land clearing was not a pressing issue for Australia’s threatened species.
This is a troubling public message, particularly as the government’s own State of the Environment Report 2016 lists “clearing, fragmentation and declining quality of habitat” as a primary driver of biodiversity decline across the continent.
These comments highlight key issues with the Threatened Species Commissioner’s current remit, made more pressing due to timing: the federal government will soon appoint a new commissioner, a “TSC 2.0”, if you will.
Threatened Species Commissioner 1.0
The commissioner’s role was established in 2014 to address the dire state of threatened species; a key initiative of the then environment minister, Greg Hunt. The remit was sixfold, including bringing a new national focus to conservation efforts; raising awareness and support for threatened species in the community; and taking an evidence-based approach to ensure conservation efforts are better targeted and co-ordinated and more effective.
Also laudable was the 2015 Threatened Species Summit, attended by some 250 delegates from a diverse set of stakeholders, which garnered significant media coverage.
But elsewhere progress has been mixed. The development of the Threatened Species Strategy is welcome, but the plan does not go nearly far enough. Key targets by 2020 are improvements in the population trajectories of 20 mammals, 20 birds and 30 plants. But this represents a mere 4% of Australia’s threatened species, excluding all threatened reptiles, amphibians, fishes and invertebrates, and most of our threatened flora.
Yet the Threatened Species Strategy mentions land clearing zero times and habitat loss just twice. Feral cats, on the other hand, are mentioned 78 times, with the plan overwhelmingly focused on culling this one invasive species. Other major introduced pests – foxes, rabbits, feral pigs and goats – are mentioned 10 times between them.
An on-ground focus and mobilising of financial and logistical resources to support threatened species recovery was a welcome development during Andrews’s tenure. His second progress report cites AU$131 million in funding for projects in support of threatened species since 2014.
Likewise, funding for threatened species must be better targeted. Of the 499 projects cited in the TSC second progress report, 361 were those of the Green Army and 20 Million Trees programs (costing AU$78 million, 60% of total funding). Neither program is specifically devoted to threatened species, and their benefit in this regard is doubtful.
The next commissioner’s checklist
Australians and democratic societies should have access to reliable, independent and objective information about the current state of our natural heritage, and how government decisions influence its trajectory. That’s a critical role that TSC 2.0 should play.
Expertise will be crucial for the new appointee. Given the complex science of species conservation, a background in environmental science is a clear requirement, just as a background in economics would be expected for the chair of the Productivity Commission, or a grounding in law for a human rights commissioner.
For a commissioner to work effectively, they must also be willing to comment on politically sensitive issues and put themselves at odds with the government when necessary. Commissioners typically work as the head of an independent statutory body, such as the Productivity Commission, the Australian Securities and Investments Commission, and the Australian Electoral Commission.
But if the TSC 2.0 is to be a truly informed and independent voice for Australia’s threatened species, the role must sit within a statutory authority, at arm’s length from government. This is the case in New Zealand, where an independent environment commission has operated since 1986. It’s time for Australia to follow suit.
Throughout history, humans have taken plants and animals with them as they travelled the world. Those that survived the journey to establish populations in the diaspora have found new opportunities as they integrate into new ecosystems.
These immigrant populations have come to be regarded as “invaders” and “aliens” that threaten pristine nature. But for many species, migration may just be a way to survive the global extinction crisis.
In our recently published study, we found that one of the Earth’s most imperilled group of species is hanging on in part thanks to introduced populations.
Megafauna – plant-eating terrestrial mammals weighing more than 100kg – have established in new and unexpected places. These “feral” populations are rewilding the world with unique and fascinating ecological functions that had been lost for thousands of years.
Today’s world of giants is only a shadow of its former glory. Around 50,000 years ago, giant kangaroos, rhino-like diprotodons, and other unimaginable animals were lost from Australia.
Formal conservation distribution maps show that much of Earth is empty of megafauna. But this is only a part of the picture.
Many megafauna are now found outside their historic native ranges. In fact, thanks to introduced populations, regional megafauna species richness is substantially higher today than at any other time during the past 10,000 years.
Worldwide introductions have increased the number of megafauna by 11% in Africa and Asia, by 33% in Europe, by 57% in North America, by 62% in South America, and by 100% in Australia.
Australia lost all of its native megafauna tens of thousands of years ago, but today has eight introduced megafauna species, including the world’s only wild population of dromedary camels.
These immigrant megafauna have found critical sanctuary. Overall, 64% of introduced megafauna species are either threatened, extinct, or declining in their native ranges.
Some megafauna have survived thanks to domestication and subsequent “feralisation”, forming a bridge between the wild pre-agricultural landscapes of the early Holocene almost 10,000 years ago, to the wild post-industrial ecosystems of the Anthropocene today.
Wild cattle, for example, are descendants of the extinct aurochs. Meanwhile, the wild camels of Australia have brought back a species extinct in the wild for thousands of years. Likewise, the vast majority of the world’s wild horses and wild donkeys are feral.
There have been global calls to rewild the world, but rewilding has already been happening, often with little intention and in unexpected ways.
A small population of wild hippopotamuses has recently established in South America. The nicknamed “cocaine hippos” are the offspring of animals who escaped the abandoned hacienda of Colombian drug lord Pablo Escobar.
By insisting that only idealised pre-human ecosystems are worth conserving, we overlook the fact that these emerging new forms of wilderness are not only common but critical to the survival of many existing ecosystems.
Megafauna are Earth’s tree-breakers, wood-eaters, hole-diggers, trailblazers, wallowers, nutrient-movers, and seed-carriers. By consuming coarse, fibrous plant matter they drive nutrient cycles that enrich soils, restructure plant communities, and help other species to survive.
The wide wanderings of megafauna move nutrients uphill that would otherwise wash downstream and into the oceans. These animals can be thought of as “nutrient pumps” that help maintain soil fertility. Megafauna also sustain communities of scavengers and predators.
In North America, we have found that introduced wild donkeys, locally known as “burros”, dig wells more than a metre deep to reach groundwater. At least 31 species use these wells, and in certain conditions they become nurseries for germinating trees.
The removal of donkeys and other introduced megafauna to protect desert springs in North America and Australia seems to have led to an exuberant growth of wetland vegetation that constricted open water habitat, dried some springs, and ultimately resulted in the extinction of native fish. Ironically, land managers now simulate megafauna by manually removing vegetation.
It is likely that introduced megafauna are doing much more that remains unknown because we have yet to accept these organisms as having ecological value.
Living in a feral world
Like any other species, the presence of megafauna benefits some species while challenging others. Introduced megafauna can put huge pressure on plant communities, but this is also true of native megafauna.
Whether we consider the ecological roles of introduced species like burros and brumbies as desirable or not depends primarily on our own values. But one thing is certain: no species operates in isolation.
Visions of protected dingoes hunting introduced donkeys and Sambar deer in Australia, or protected wolves hunting introduced Oryx and horses in the American West, can give us a new perspective on conserving both native and introduced species.