More sightings of an endangered species don’t always mean it’s recovering



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Leadbeater’s possum sightings are up – but that doesn’t mean the critically endangered species is recovering.
David Lindenmeyer, Author provided

David Lindenmayer, Australian National University

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.


Read more: Victoria must stop clearfelling to save Leadbeater’s possum


Why more sightings may not mean species recovery

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.


Read more: Australia’s species need an independent champion


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.

Another key threatening processes which has not been addressed is fire. Victoria’s wet ash forests are extremely fire prone, in part because forests that regenerate after logging are significantly more likely to burn at elevated severity.

The significant risks facing the mountain ash forests in which Leadbeater’s possum lives has resulted in the forest itself being classified as critically endangered.

No grounds for reducing the conservation status

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.

The ConversationMore formally protected areas, and not downlisting their conservation status, is the most scientifically robust option for the conservation of this iconic animal.

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University

This article was originally published on The Conversation. Read the original article.

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Australia: Sydney – Green and Golden Bell Frog


The link below is to a media release concerning the Green and Golden Bell Frog, an endangered frog species in New South Wales, Australia.

For more visit:
http://www.environment.nsw.gov.au/media/OEHMedia17071801.htm

The lengthy childhood of endangered orangutans is written in their teeth



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A young Bornean orangutan nursing.
Erin Vogel, Author provided

Tanya M. Smith, Griffith University

Orangutan populations in the wild are critically endangered, and one of the things that may hamper their survival is the time they take to rear new offspring. The Conversation

An orangutan mother will not give birth again until she’s finished providing milk to her previous offspring. Nursing can take a long time and vary across seasons, as we found in research published today in Science Advances.

Primate mothers, including humans, raise only a few slow-growing offspring during their reproductive years.

Differences in infant development have a profound effect on how many children a female can have over the course of her life – the key marker of success from an evolutionary vantage point.

Great apes have a high-stakes strategy. Chimpanzee mothers nurse their offspring for five years on average, twice as long as humans in traditional small-scaled societies.

Orangutans have been suspected of having even longer periods of infant dependency, although determining just how long has been a particular challenge for field biologists.

Wild orangutan from Gunung Palung National Park, Borneo, Indonesia with her one month old infant. (Gunung Palung Orangutan Project)

Living high up in dwindling Southeast Asian forests, these apes are adept at evading observers. Their nursing behaviour is often concealed, particularly while juveniles cling to their mother or rest together in night nests.

Maintaining continuous field studies to track their development is expensive, and efforts are hindered by frequent forest fires and devastating deforestation for palm oil plantations.

Teeth tell the story

I have spent the past few decades studying how orangutans and other primates form their teeth. Amazingly, every day of childhood is captured during tooth formation, a record that begins before birth and lasts for millions of years.

Teeth also contain detailed dietary, health and behavioural histories, allowing biological anthropologists an unprecedented window into the human past.

I’ve also teamed up with researchers Manish Arora and Christine Austin, at Icahn School of Medicine at Mt Sinai in New York, who have pioneered methods to map the fine-scaled elemental composition of teeth, as well as primate lactation expert Katie Hinde at Arizona State University.

We have shown in a previous study that tiny amounts of the element barium are an accurate marker of mother’s milk consumption. Like calcium, barium is sourced from the mother’s skeleton, concentrated in milk, and ultimately written into the bones and teeth of her offspring.

Tooth growth creates daily lines (indicated by short white lines), as well as a neonatal line (NL) at birth. Growth starts at the junction between enamel and dentine, and progresses away from the junction and towards the root (arrows).
Christine Austin and Tanya Smith

Once animals start nursing after birth, their teeth show increases in barium values, which begin to decrease when solid food is added to the diet. These values drop further to pre-birth levels when primates stop nursing and are weaned.

We’ve recently used this approach to explore the nursing histories of wild orangutans in collaboration with orangutan expert Erin Vogel at Rutgers University. In order to do so, I borrowed teeth housed in natural history museums from individuals that had been shot many years ago during collection expeditions.

Wild Bornean orangutan mother and suckling 19-month old infant.
Paige Prentice, Author provided

Orangutan teeth show a gradual increase in barium values from birth through their first year of life, a time of increasing consumption of their mother’s milk. After 12-18 months, values decrease as infants begin eating solid foods consistently.

But surprisingly, barium levels then begin to fluctuate on an approximately annual basis. We suspect that this is due to seasonal changes in food availability. When fruit is in short supply, infants appear to rely more on their mother’s milk to meet their nutritional needs.

Light microscope image (left) of a wild orangutan molar contrasted with an elemental map of the same tooth (right) showing the distribution of barium. The timing of barium incorporation was determined from accentuated lines (in days of age on the left), which form during enamel and dentine secretion. Approximately annual bands of enriched barium are apparent in the dentine after the first year, likely due to seasonal increases in mother’s milk intake.
Smith et al. (2017) Science Advances

Hanging around

Another surprising finding is that nursing may continue for more than eight years, longer than any other wild animal.

This information is the first of its kind for wild Sumatran orangutans, as they have been especially difficult to study in their native habitat. Previous estimates from two wild Bornean orangutans suggested that juveniles nurse until about six to eight years of age.

Rather than spending so much time and energy breastfeeding their children, human mothers in traditional societies transition their infants onto soft weaning foods around six months of age, tapering them off milk a few years later.

Humans also benefit from having help such as older siblings and grandparents who lend a hand with childcare and enable women to energetically prepare for having their next child.

Orangutan mothers have it hard by comparison. They live alone in unpredictable environments with limited nutritional resources. In order to survive they use less energy than other great apes, raising their young more slowly.

Wild orangutan mother and 11-month old infant.
Tim Laman, Author provided

Vulnerable orangutans

Female orangutans begin reproducing around age 15 and can live until 50 years old in the most favourable of circumstances. They bear new offspring every six to nine years, producing no more than six or seven descendents over their lifetime.

Having a long nursing period and slow maturation makes orangutan populations especially vulnerable to environmental perturbations.

Recent work has also implicated poor habitat quality and the pet trade as additional factors in their rapidly declining numbers, which is underscored by their critically endangered status.

Research on collections housed in natural history museums provides timely evidence of how remarkable orangutans are, how much information we can retrieve from their teeth, and why conservation efforts informed by evolutionary biology are critical.

Tanya M. Smith, Associate Professor in the Australian Research Centre for Human Evolution, Griffith University

This article was originally published on The Conversation. Read the original article.

The bark side: domestic dogs threaten endangered species worldwide



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A feral dog chasing a wild boar, Banni grasslands, India.
Chetan Misher/Facebook

Tim Doherty, Deakin University; Aaron J. Wirsing, University of Washington; Chris Dickman, University of Sydney; Dale Nimmo, Charles Sturt University; Euan Ritchie, Deakin University, and Thomas Newsome, Deakin University

Humans and their canine companions share many close bonds. Wolves (Canis lupus) were the first animal domesticated by people, some time between 15,000 and 50,000 years ago. The Conversation

There are now an estimated 1 billion domestic dogs across their near-global distribution.

Domestic dogs include feral and free-ranging animals (such as village and camp dogs), as well as those that are owned by and completely dependent on humans (pet dogs).

Our latest research reveals that the ecological “pawprint” of domestic dogs is much greater than previously realised.

Using the IUCN Red List of Threatened Species, we counted how many species are negatively affected by dogs, assessed the prevalence of different types of impacts, and identified regions with the greatest number of affected species.

A dog with a black-naped hare, Maharashtra, India.
Hari Somashekhar/Facebook

Dogs are third-most-damaging mammal

We found that dogs are implicated in the extinction of at least 11 species, including the Hawaiian Rail and the Tonga Ground Skink. Dogs are also a known or potential threat to 188 threatened species worldwide: 96 mammal, 78 bird, 22 reptile and three amphibian species. This includes 30 critically endangered species, two of which are classed as “possibly extinct”.

These numbers place dogs in the number three spot after cats and rodents as the world’s most damaging invasive mammalian predators.

Even though dogs have an almost global distribution, the threatened species they are known to affect are concentrated in certain parts of the globe. South-East Asia, South America, Central America and the Caribbean each contain 28 to 30 threatened species impacted by dogs. Other hotspots include Australia, Micro/Mela/Polynesia and the remainder of Asia.

Lethal and non-lethal impacts

Predation was the most commonly reported impact of dogs on wildlife. The typically omnivorous diet of dogs means they have strong potential to affect a diversity of species. For instance, dogs killed at least 19 endangered Kagu (a ground-dwelling bird) in New Caledonia in 14 weeks. Threatened species with small population sizes are particularly vulnerable to such intense bouts of predation.

The frequency of different types of dog impact on threatened species.
https://authors.elsevier.com/a/1Uxs~1R~e71Xl

Aside from simply killing animals, dogs can harm wildlife in other ways, such as by spreading disease, interbreeding with other canids, competing for resources such as food or shelter, and causing disturbances by chasing or harassment. For example, contact with domestic dogs increases disease risk for endangered African Wild Dogs in Kenya.

Part of the problem is that when wild animals perceive dogs as a threat, they may change their behaviour to avoid them. One study near Sydney found that dog walking in parklands and national parks reduced the abundance and species richness of birds, even when dogs were restrained on leads.

None of the Red List assessments mentioned such indirect risk effects, which suggests that their frequency is likely to be much higher than reported.

Feral dogs chasing Indian wild ass at Little Rann of Kutch, India.
Kalyan Varma/Facebook

Friend and foe

Despite their widespread and sometimes severe impacts on biodiversity, dogs can also benefit some species and ecosystems.

For example, in Australia, the closely related dingo (Canis dingo) can suppress populations of introduced predators such as red foxes (Vulpes vulpes), and in doing so can benefit smaller native prey. It is possible that domestic dogs could perform similar ecological roles in some situations.

In some regions, dogs and their keen noses have been trained to help scientists find threatened species such as Tiger Quolls. Elsewhere they are helping to flush out and control feral cats.

An emerging and exciting conservation role for dogs is their growing use as “guardian animals” for wildlife, with the remarkable story of Oddball being the most well known.

Managing the problem

Dogs not only interact with wildlife, but can also attack and spread disease to humans, livestock and other domestic animals. As such, managing the problem requires looking at ecological, cultural and social perspectives.

Some of the regions with high numbers of species threatened by dogs are also hotspots for urbanisation and road building, which make it easier for dogs to access the habitats of threatened species. Urban development increases food waste, which feeds higher numbers of dogs. As dogs expand into new areas, the number of species they impact is likely to grow.

Street dogs scavenging food waste in India.
Achat1234/wikimedia

We can protect wildlife by integrating human health and animal welfare objectives into dog management. Vaccination and desexing campaigns can reduce disease risk and overpopulation problems. We should also focus on responsible dog ownership, removing dogs without owners, and reducing access to food waste.

Given the close relationship between humans and dogs, community engagement should form the basis of any management program. More research is needed to get a better picture of the scale of the problem, and of how dogs interact with other threats such as habitat loss. Such actions are critically important for ensuring the conservation of wildlife threatened by dogs around the world.


This article was co-authored by Dr Al Glen from Landcare Research, New Zealand and Dr Abi Vanak from the Ashoka Trust for Research in Ecology and the Environment, India. These institutions had no role in the design or funding of this research.

Tim Doherty, Research Fellow, Deakin University; Aaron J. Wirsing, Assistant Professor, School of Environmental and Forest Sciences, University of Washington; Chris Dickman, Professor in Terrestrial Ecology, University of Sydney; Dale Nimmo, ARC DECRA Fellow, Charles Sturt University; Euan Ritchie, Senior Lecturer in Ecology, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, and Thomas Newsome, Fulbright Scholar and Postdoctoral Research Fellow, Deakin University

This article was originally published on The Conversation. Read the original article.

Here’s a good news conservation story: farmers are helping endangered ecosystems


David Lindenmayer, Australian National University; Chloe Sato, Australian National University; Dan Florance, Australian National University, and Emma Burns, Australian National University

There a many reasons to be unhappy about the state of the environment. But we’ve recently found some good news: a conservation program that works.

You probably haven’t heard of the Environmental Stewardship Program (ESP). It was a market-based agri-environment program that ran between 2007 and 2012, which funded farmers to conserve threatened ecosystems on their property. Land managers were given contracts for up to 15 years to deliver results.

Overall, 297 land managers will receive about A$152 million over roughly 18 years to implement their conservation management plans. The last of these contracts will end in 2027. No new funding rounds are expected.

There’s been a variety of market-based programs for conservation on farmland in Australia, but we don’t know what the total investment is to date. And we are not aware of scientific monitoring that demonstrates their impact.

A property conserving box gums as part of the program.
Author provided

Endangered ecosystems

The box gum grassy woodlands of eastern Australia are home to several hundred species of native birds, including the iconic superb and turquoise parrots, thousands of native plants (such as the chocolate lily that leaves a deliciously rich and sweet aroma in native pastures), and beautiful mammals like the squirrel glider.

Box gum grassy woodlands have been 95% to 99% cleared for wheat and sheep grazing and are listed as nationally critically endangered.

Box gum grassy woodland is found across eastern Australia.
Author provided.

Under the ESP, more than 150 farmers from southern New South Wales to southeast Queensland have been funded to conserve the box gum grassy woodland ecosystem. This is one of the largest projects of its type in the world.

Farmers undertake controlled grazing by livestock in woodland remnants, replant native woodland, avoid firewood harvesting, cease bushrock removal, and control weeds and feral animals.

But we can’t know if a conservation program is working unless we monitor it. Fortunately, soon after it started, the Australian National University was commissioned to design a monitoring program for the ESP. We have now been monitoring these efforts for six years – and the results are exciting.

Better for wildlife…

So far, the data show that the farmers are doing a good job and it is money very well spent.

To find out if the program is working, we have to compare managed (conserved) areas with “control patches” – patches where land owners haven’t done anything. This comparison shows that funded management patches have fewer environmental weeds, greater native plant species richness, more natural regeneration of native plants, smaller areas of erodible bare ground, and more species of woodland birds.

In the space of six years, the Australian government, in concert with Australian farmers (through modest investment), has generated significant, positive environmental changes on farms. In fact, the box gum project can set the bar for many other conservation programs.

…better for farmers

The positive impacts go beyond improvement of the environment, because there have been notable social benefits too.

A bearded dragon, one of the species found in grassy woodlands.
CM, Author provided

Farmers are now highly motivated to deliver better environmental outcomes on their farms and showcase the integration of the multiple objectives of agricultural production and conservation.

The income stream they received also helped some survive the almost unprecedented hardships associated with the Millennium Drought in the mid- to late 2000s.

More generally, regular feedback and discussions between ANU field ecologists and landholders over the past six years has provided anecdotal evidence that farmers engaged in successful environmental programs suffer fewer problems with mental illness. This landholder goodwill and change in attitude towards land management is something that will far outweigh the 15-year investment in the program.

A model for conservation

Despite its success, the program has not been without detractors who see the policy and monitoring as over-engineered or boutique. This is primarily because its design, implementation, and monitoring standards are politically and bureaucratically inconvenient. They are not well suited to a reactive, short-term focused society.

In the case of monitoring, some considered it wasteful to establish and monitor control sites (areas where there has been no management). Yet without the controls, we couldn’t tell this positive story.

This is an exciting example of successful private-public land conservation and how it can be integrated with agricultural production (the primary land use of much of Australia’s land surface).

The long-term funding model is a more sensible approach than one-off payments, and provides a realistic timeframe to achieve results.

The Australian government should be congratulated and encouraged to invest in more programs of this type. It has worked because it was designed specifically to link farmers, scientists and policy makers.

Billions of dollars are expended on the environment in Australia every year. Landscape recovery will span multiple governmental cycles and every dollar must be spent wisely. Programs like ESP give some guidance on how large-scale environmental programs can be more successful.

For further information on conservation programs like the Environmental Stewardship Program, see our new e-book

The Conversation

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University; Chloe Sato, Postdoctoral fellow in applied vegetation ecology, Australian National University; Dan Florance, Research officer, Fenner School of Environment & Society ANU College of Medicine, Australian National University, and Emma Burns, Executive Director, Long Term Ecological Research Network; Fenner School of Environment and Society, Australian National University

This article was originally published on The Conversation. Read the original article.