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Daily Archives for April 30, 2019
Dingoes and humans were once friends. Separating them could be why they attack
Katie Woolaston, Queensland University of Technology
Two small children were hospitalised in recent weeks after being attacked by dingoes on K’gari (Fraser Island).
The latest attack involved a 14-month-old boy who was dragged from his family campervan by dingoes, an incident that could have ended with much more serious consequences than the injuries he sustained.
Fraser Island, famous for its wild dingo population, was renamed K’Gari in 2017. And the number of tourists involved in negative interactions with dingoes appears to be increasing.
Read more:
Why do dingoes attack people, and how can we prevent it?
The dingo, a wild dog of the Canis genus, were likely brought to Australia by Asian seafarers around 4,000 years ago.
Shutterstock
While dingoes exist in many parts of Australia today, those on K’gari are thought to be “special” because of their genetic purity. This means they have not interbred with wild and domestic dogs to the same extent mainland dingoes have, and so are considered the purest bred dingoes in Australia.
They are legally protected because of this special status, and because they live in a national park and World Heritage Area. Unfortunately, it is precisely this protection and separation from humans that has driven much of the increase in interaction and aggression towards people.
Read more:
Like cats and dogs: dingoes can keep feral cats in check
This ongoing human-dingo conflict on K’Gari shows how our laws and management practices can actually increase negative encounters with wildlife when they don’t consider the history, ecology and social circumstances of the conflict area.
Law and policy ‘naturalised’ dingoes
The island’s laws and policies, such as the international World Heritage Convention and the more local Fraser Island Dingo Conservation and Risk Management Strategy, are focused on conserving a particular human idea of “natural wilderness”.
In practice, this means the management policy focuses on “naturalising” the dingo by effectively separating them from people and the sources of food they bring.
But dingoes, although wild animals, have never effectively been naturalised on K’Gari, so our attempts to maintain their “natural” and “wild” status is not entirely accurate.
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Dingoes have a long history of being close with Aboriginal people. This human-dingo relationship continued as the island was used for mining and logging, as employees also lived with dingoes. They were fed by people, scavenged scraps from rubbish tips, and fed on leftover fish offal.
It is only in the last few decades we have sought to rewild dingoes by removing all forms of human-sourced food, separating them from human settlement.
Read more:
Living blanket, water diviner, wild pet: a cultural history of the dingo
Separating the animals from humans won’t work, however, when more than 400,000 tourists visit K’Gari every year, expecting to see a dingo.
International law and local management prioritise tourism, and a tourism-based economy is certainly preferable to the logging and sand-mining economies that existed before the national park was given World Heritage status in 1992.
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But are such large visitor numbers in a relatively small space sustainable?
This question has been asked often, including by the Queensland government in their Great Sandy Region Management Plan.
Yet, there has been no serious consideration given to reducing tourist numbers or increasing fees, despite research suggesting visitors are willing to sacrifice some access for improved environmental outcomes and less crowding.
Such proposals have been specifically rejected by decision-makers within the Dingo Management Plan.
Read more:
Dingoes do bark: why most dingo facts you think you know are wrong
So where does that leave us?
We essentially have three options:
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if we wish to stick with the policy of dingo naturalisation and human separation, we must change our attitudes and values towards dingoes so people maintain an appropriate distance and do not inadvertently feed them. This can happen with education, fines and collaboration. While this is essentially what policies have attempted so far, there has been little effect on overall incident numbers
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we can take the naturalisation policy to its expected endpoint and completely separate tourists and dingoes. This may mean more fencing, greater fines and fewer annual visitors so rangers can educate and manage all visitors effectively
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we can drastically reevaluate how we value wildlife and how we place ourselves within the natural world. This would see an enormous overhaul of the regulatory framework, and would also require a deeper understanding of all the causes of conflict, other than just the immediate issue of tourism, habituation and feeding.
In practice, an effective dingo management policy would probably require a combination of all three options to maintain the pristine state of K’Gari, conserve the dingo population and improve human safety.
Katie Woolaston, Lawyer, Queensland University of Technology
This article is republished from The Conversation under a Creative Commons license. Read the original article.
How many species on Earth? Why that’s a simple question but hard to answer
Shutterstock/ju see
Tanya Latty, University of Sydney and Timothy Lee, University of Sydney
You’d think it would be a simple piece of biological accounting – how many distinct species make up life on Earth?
But the answer may come as a bit of a shock.
We simply don’t know.
We know more accurately the number of books in the US Library of Congress than we know even the order or magnitude – millions and billions and so on – of species living on our planet, wrote the Australian-born ecologist Robert May.
Read more:
Trapdoor spider species that stay local put themselves at risk
Current estimates for the number of species on Earth range between 5.3 million and 1 trillion.
That’s a massive degree of uncertainty. It’s like getting a bank statement that says you have between $5.30 and $1 million in your account.
So why don’t we know the answer to this fundamental question?
It’s hard to count life
Part of the problem is that we cannot simply count the number of life forms. Many live in inaccessible habitats (such as the deep sea), are too small to see, are hard to find, or live inside other living things.
So, instead of counting, scientists try to estimate the total number of species by looking for patterns in biodiversity.
In the early 1980s, the American entomologist Terry Erwin famously estimated the number of species on Earth by spraying pesticides into the canopy of tropical rainforest trees in Panama. At least 1,200 species of beetle fell to the ground, of which 163 lived only on a single tree species.
Assuming that each tree species had a similar number of beetles, and given that beetles make up about 40% of insects (the largest animal group), Erwin arrived at a controversial estimate of 30 million species on Earth.
Many scientists believe the 30 million number is far too high. Later estimates arrived at figures under 10 million.
In 2011, scientists used a technique based on patterns in the number of species at each level of biological classification to arrive at a much lower prediction of about 8.7 million species.
Shutterstock/Suttipon Thanarakpong
All creatures great and very, very small
But most estimates of global biodiversity overlook microorganisms such as bacteria because many of these organisms can only be identified to species level by sequencing their DNA.
As a result the true diversity of microorganisms may have been underestimated.
After compiling and analysing a database of DNA sequences from 5 million microbe species from 35,000 sites around the world, researchers concluded that there are a staggering 1 trillion species on Earth. That’s more species than the estimated number of stars in the Milky Way galaxy.
But, like previous estimates, this one relies on patterns in biodiversity, and not everyone agrees these should be applied to microorganisms.
It’s not just the microorganisms that have been overlooked in estimates of global biodiversity. We’ve also ignored the many life forms that live inside other life forms.
Most – and possibly all – insect species are the victim of at least one or more species of parasitic wasp. These lay their eggs in or on a host species (think of the movie Aliens, if the aliens had wings). Researchers suggest that the insect group containing wasps may be the largest group of animals on the planet.
What do we mean by species?
A more fundamental problem with counting species comes down to a somewhat philosophical issue: biologists do not agree on what the term “species” actually means.
The well-known biological species concept states that two organisms belong to the same species if they can interbreed and produce fertile offspring. But since this concept relies on mating, it cannot be used to define species of asexual organisms such as many microorganisms as well as some reptiles, birds and fish.
It also ignores the fact that many living things we consider separate species can and do interbreed. For example, dogs, coyotes and wolves readily interbreed, yet are usually considered to be separate species.
PLOS One (L. David Mech et al), CC BY
Other popular species definitions rely on how similar individuals are to one another (if it looks like a duck, it is a duck), their shared evolutionary history, or their shared ecological requirements.
Yet none of these definitions are entirely satisfactory, and none work for all life forms.
There are at least 50 different definitions of a species to choose from. Whether or not a scientist chooses to designate a newly found life form as a new species or not can come down to their philosophical stance about the nature of a species.
The cost of species loss
Our ignorance about the true biodiversity on our planet has real consequence. Each species is a potential treasure trove of solutions to problems including cures for disease, inspirations for new technologies, sources of new materials and providers of key ecosystem services.
Yet we are living in an age of mass extinction with reports of catastrophic insect declines, wide-scale depopulation of our oceans and the loss of more than 50% of wildlife within the span of a single human life.
Our current rate of biodiversity loss means we are almost certainly losing species faster than we are naming them. We are effectively burning a library without knowing the names or the contents of the books we are losing.
So while our estimate of the number of species on the planet remains frustratingly imprecise, the one thing we do know is that we have probably named and described only a tiny percentage of living things.
New species are turning up all the time, at a rate of roughly 18,000 species each year. For example, researchers in Los Angeles found 30 new species of scuttle fly living in urban parks, while researchers also in the US discovered more than 1,400 new species of bacteria living in the belly buttons of university students.
Even if we take the more conservative estimate of 8.7 million species of life on Earth, then we have only described and named about 25% of life forms on the planet. If the 1 trillion figure is correct, then we have done an abysmally poor job, with 99.99% of species still awaiting description.
It’s clear our planet is absolutely teeming with life, even if we cannot yet put a number to the multitudes. The question now is how much of that awe-inspiring diversity we choose to save.
Tanya Latty, Senior Lecturer, School of Life and Environmental Sciences, University of Sydney and Timothy Lee, Associate Lecturer in Life and Environmental Sciences, University of Sydney
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Kevin's Walk on the Wild Side 