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Introduction: Extinctions in Near Time
December 14, 2011 01:10 PM PST
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Welcome to our podcast: Extinctions in Near Time-Biodiversity Loss Since the Pleistocene. Hello, my name is Liz Hadly and I am a professor of Biology at Stanford University. What you are about to hear is a series of episodes featuring nine freshman and one sophomore about the causes and consequences of extinction. None of these students had ever produced a podcast like this before, and each episode is a product of their own work. We hope you enjoy listening to these episodes as much as we enjoyed making them.

Thanks to the Stanford Introductory Seminar Program for supporting this project, and to Liz Neeley for her ‘Podcasting 101’ guidance.

December 15, 2011 05:50 PM PST
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Short intros for each episode

Photo: Creative Commons: Matt-80

Animal magnetism and conservation by Jack Werner
December 15, 2011 05:51 PM PST
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Some call it cuteness, some call it charisma, some even call it animal magnetism: Hi, I’m Jack Werner, and today I’ll be talking about why we try so much harder to conserve likeable species and what this means for endangered animals everywhere.

With me is my good friend, Not me.

Not me:
Hello there

Let’s get to it. From China’s giant pandas to the elephants of the African savanna to America’s iconic bald eagles, there are some animals that just captivate us.

In fact, a study estimated that 54% of all wildlife funding in the United States is devoted to just 1.8% of America’s endangered species.

Not me:
Why exactly do we value some endangered species so much more than others?

Most endangered species aren’t economically valuable, so we usually value them for emotional reasons. Different people are captivated by different animals, but there are some general patterns to what people like. Typically, physical and behavioral similarity to humans is an important factor.

Gorillas hold their babies like we do. Chimps use elaborate tools. Elephants mourn their dead. All these actions resonate with us.

Not me:
What else?

Another huge factor, so to speak, is size. Large animals awe us and instinctively demand our respect. Culture plays a large role too. If an animal is deemed sacred in a certain religion, such as cows in Hindu India, you can bet they’ll be conserved.

Not me:
So basically, the pretty, strong, and cool animals get all the attention. Sounds like high school. But ugly, small, or less dramatic animals don’t have any less of a right to exist, do they?

No, they absolutely have the same right to exist. And this brings us to an interesting point. Conservation groups that seem to care about only charismatic animals actually help broad swaths of animals, and they do so in a fascinating way.

First, they’ve guessed that people are much more likely to give money to conserve the Panda than, say, the south China Sika deer, which lives in the same area.

By that alone, they’re able to conserve more species.

But the really cool thing is that these charismatic animals are sometimes keystone species, and saving them can often help preserve all animals in their ecosystem. The logic is that if animals at the top are thriving, everything below them in the foodchain must be doing ok.

Not me:
Do you have any examples of that?

Sure. The reintroduction of wolves to Yellowstone helped keep elk populations in check, which resulted in a large increase in plant biomass.

Many targeted charismatic species have huge ranges, like the Siberian tiger. Saving this tiger means making sure it has room to roam, and this helps all the animals in the forest.

Another example is the spotted owl. These owls need old growth forests to survive, so protecting the owls means saving the trees they nest in from logging.

Not me:
Ok, you’ve convinced me that people are more willing to save charismatic species. But if people only care about specific species, wouldn’t they be fine with just putting them in zoos and not helping overall ecosystems?

Great question. Although there hasn’t been much work done on this, I’ll give a tentative no. In 2003, economists conducted a study on people’s willingness to pay to conserve pandas. They found that the average American is willing to pay $3.90 to care for caged pandas and $8.43 for penned pandas. But their respondents were willing to pay a whopping $14.86 for a panda reserve. Extrapolating, this means that people value charismatic animals living in their natural environments, which will indirectly lead to the preservation of everything else in those ecosystems. Ideally, entire environments would be conserved for their own sake, but these charismatic animals can be tremendously effective proxies.

Not me:

Absolutely. That’s all the time we have for today; thank you for listening. Until next time, this has been Jack Werner for Hadly’s Holoceneapalooza.

Photo: Creative Commons by J Patrick Fischer

Are Worms Worthy of Conserving? by Jack Werner
December 15, 2011 05:52 PM PST
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Me: In the last episode, we talked about efforts to save charismatic animals from extinction. In this episode, we ask a very different question: is it ever ok to MAKE an animal go extinct?

Not me: Of course not. It's immoral to just wipe a living creature off the face of the earth.

Me: Well, let me tell you about an animal I - and the U.N. - think should be made extinct: the guinea worm.

Guinea worms are these tiny little worms found in Asia and Africa.

Not me: Nothing wrong with worms.

Me: This worm is a parasite. People drink dirty water containing the worm's larvae, and these larvae burrow into their host's stomach and intestines.

Photo from Wikipedia
Not me: So what? There's plenty of food to go around.

Me: I’ll tell you. After growing for about a year, the worm migrates to your feet, causing excruciating pain as it slithers through your leg. Then…a blister forms. Slowly, a worm three feet long and as thick as a spaghetti noodle crawls through your ruptured blister. The process often takes days, but the worst part about it is the horrible burning sensation you feel while the worm tunnels out of your body. Because it feels like your leg is on fire, you put your leg in water…at which point the worm releases her eggs, and the cycle starts all over again.

Not me: KILL IT

Me: Not so fast. These worms have brains and heartbeats and little worm children.

Not me: KILL IT

Me: Well, I do believe the guinea worm should be destroyed, but it helps to use something other than emotion in these decisions.

There are generally two ways the value of a species is measured: instrumental value and intrinsic value.

Instrumental value is the value of an animal as a means to an end. For example, bees pollinate about 2 billions dollars worth of crops in California each year.

Intrinsic value is a little trickier to understand. Basically, it's the value an animal has in and of itself. There is some debate on what makes an animal have intrinsic value, but many ethicists think characteristics like self-awareness, a conception of existing over time, and holding preferences for the future are key.

Not Me: So how does the worm stack up?

Me: Well, it has negative instrumental value - it causes excruciating pain to people and doesn't seem to have any benefit. And its intrinsic value is pretty low - as such a simple animal, it is unlikely to fulfill many of the requirements of intrinsic value.

Not me: So it's okay to get rid of it?

Me: Yes, and people have been trying. In 1986, there were 3 and a half million cases of guinea worm disease. In 2010, there were less than two thousand.

However, the decision to make an animal go extinct cannot be taken lightly. Just because an animal grosses us out does not mean it's alright to kill it. And many animals have hidden instrumental values. Next episode we'll talk about two more creatures, the disgusting leech and the lethal cigarette snail.

Both of these animals, it turns out, have fantastic benefits for humans.

But that's all the time we have for today. Thanks for listening.

Photo: PD-USGOV.

Megafaunal Loss by Mark Valentine
December 15, 2011 05:52 PM PST
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Hello again. Like I said before, I’m Mark Valentine and I’m going to be talking about Megafaunal Extinction and how it affects present and future biodiversity. Before I begin, you probably are going to want to know what exactly Megafauna are. Megafauna are HUGE animals. This would certainly include animals like elephants and giraffes, but also lions, tigers and bears. All these animals, however, are relatively well known and still exist in the world today. What many people don’t know is that there were many incredible Megafauna that existed a few thousand years ago that are now extinct. Around 50,000 years ago, at the end of the last Ice Age, Megafauna worldwide underwent massive and widespread extinctions . Before then, there were all kinds of amazing and enormous animals worldwide: In Eurasia, there were wooly mammoths and saber tooth cats, which you’ve probably heard of, but in North America there were beavers the size of small cars and 9 foot tall Bison with horns that spanned over 6 feet , in South America there were 5 foot tall armadillos and Giant Ground Sloths the size of elephants , and in Australia there were wombats the size of Hippopotamuses . All these animals have two things in common: One, that they are absolutely massive, and two, that they have all contributed to the historical phenomenon that Megafauna are more likely to go extinct than smaller animals . So what caused these extinctions? There are two causes. We know that human hunting lead to the extinction of many Megafaunal species, like Steller’s Sea Cow, which was basically a 30 feet long , 20,000 pound manatee . Another major cause of these extinctions was climate change. A recent study showed that climate change had significant effect on many species, and actually may have been the cause of extinction for wooly rhinos, giant bison, and other Megafauna . So what does this mean for present and future biodiversity? It’s not good. The same two factors—humans and climate—are again playing a role in Megafaunal extinctions. As humans increase in population and expand outwards, more and more animals are being threatened, and since Megafauna need more living space than other animals they are more affected. Animals including pandas and tigers are already endangered because of this. We’re also experiencing global climate shifts due to global warming, which is already causing a decline in Megafauna like the polar bear . The continued global trend of a loss of large animals is clearly leading towards one result: a world overrun with the smallest kinds of animals which can live alongside humans, or in other words, a world overrun with rodents . But this does not have to happen. If we as humans can dramatically change the way we live to reduce climate change and preserve wildlife, we can maintain biodiversity, especially among Megafauna, for much longer. The only question is, can we change? ```
Wikipedia contributors. "Quaternary extinction event." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 20 Nov. 2011. Web. 30 Nov. 2011.
Kurtén, B. and E. Anderson (1980). Pleistocene Mammals of North America. Columbia University Press. pp. 236–237. ISBN 0231037333.
Wikipedia contributors. "Bison latifrons." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 13 Nov. 2011. Web. 30 Nov. 2011.
Wikipedia contributors. "Doedicurus." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 16 Jun. 2011. Web. 30 Nov. 2011.
Wikipedia contributors. "Megatherium." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 10 Oct. 2011. Web. 30 Nov. 2011.
Wikipedia contributors. "Diprotodon." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 26 Nov. 2011. Web. 30 Nov. 2011.
Turvey S. T., Fritz S. A. 2011 The ghosts of mammals past: biological and geographical patterns of global mammalian extinction across the Holocene. Phil. Trans. R. Soc. B 366, 2564–2576.
Sally M. Walker (1999). Manatees. Lerner Publications.
Victor B. Scheffer (November 1972). "The Weight of the Steller Sea Cow". Journal of Mammalogy 53
Hofrieter, Michael., Shapiro, Beth., et al. 2011. Species-specific responses of Late Quaternary megafauna to climate and humans. Nature 479, 359–364 (17 November 2011)
Johnson, Chris. Australia's Mammal Extinctions: A 50,000 year history. 1st ed. Caimbridge: Caimbridge University Press, 2006. Print.
Hunter, Christine M., Hal Caswell, Michael C. Runge, Eric V. Regehr, Steve C. Amstrup, and Ian Stirling. 2010. Climate change threatens polar bear populations: a stochastic demographic analysis. Ecology 91:2883–2897

The last female just died: A tale from Guam. By Joseph Topasna
December 15, 2011 05:53 PM PST
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Why has the Pacific Island of Guam gone from sounding…like this...to a little more like this...

Hello again everyone!
My name is Joseph, and today I’m reporting to you all from the always beautiful Stanford University.
Before we dive in, first a little about me. You see, I was born on the island of Guam 18 years ago. The silence you got a brief glimpse of is extremely concerning for me. Many species of animals on Guam have disappeared forever- that’s the silence. For my generation of Guamanians, this pestilent silence has nowadays become common place. Sixty years ago my grandfather would have heard all of those beautiful birds. Where.have.they.gone?
Why has the island of Guam become a quieter place?!

And it looks like we have caller! You're live caller #1, what do you have to say on the subject?
Oh goodness me, not again. Make it quick captain yosef.
I have the answer to your question!!! NOW...
Come with me across the Pacific to peer at the answer in the form of an evolutionarily gifted predator.
It looks *pause* like this: It has…large unblinking eyes… elliptical pupils. It is the perfect hunter who, lacking appendages, will strike, and constrict its prey with its body. Then it will chew…and chew with its venomous rear fangs… until the helpless victim is poisoned, and ready for consumption.

OOOOOK, that's enough from you.
He's spot on though
What is this tank of nature? It’s the Brown Tree Snake.

The Brown Tree Snake’s home is Papua New Guinea and Northern and Eastern Coastal Australia. However, it has found new home. Research estimates that around the late 1940s, the Brown Tree snake was inadvertently transported in a cargo ship to the Island of Guam where it quickly found an abun dance of defenseless prey. The Brown Tree Snake targeted nearly every animal on Guam, including Guam’s 13 native forest birds. Of those 13 bird species, only 3 species of birds have survived. The lone bird you hear now is the Mariana crow. The last female crow on Guam died earlier this year, and there are only two male crows left.

We can’t let this silence spread across the Pacific to other islands. We, the public, must express our concerns about our beloved islands across the Pacific to let Governments know that we strongly support policies that control Brown Tree Snake populations, and prevent the Brown Tree Snake from being inadvertently transported once again.

So far, trapping snakes has been the most successful way to protect what birds remain. Proposed ideas like introducing predators to eat the Brown Tree Snakes hold little value since there are no other predators on Guam to eat those predators in turn. For example, if a predator like the mongoose were brought to Guam to eat the snakes, then Guam would just have a mongoose problem in place of its snake problem.

With that in mind, the greatest thing that Guam and other pacific islands can do (and have done) is invest in Brown Tree Snake prevention. Prevention measures are easy to enact--- Simple measures that include inspecting ship cargo, and any kind of shipment in and out of Pacific islands.

Everything aside though, we need to step back and realize that we can’t see the Brown Tree Snake as an evil animal. It is our fault, not the fault of the Brown Tree Snake, that Guam’s birds have become extinct. The animals of Guam, and the Brown Tree Snake played according to the rules--- they have all been living to the best of their abilities in their environments. And just because the Brown Tree Snake can do its job incredibly well, we can’t fault this skilled hunter for success.

You are the future, and now that you know how our simple, human mistakes impact the natural world, I invite you to remain conscious of human interaction with living and non-living environments. Collectively, it is an educated and conscious human population that will tend towards harmony with nature. Thank you for listening.

Stophlet, John J. 1946. Birds of Guam. The Auk 63: 534-40.
Savidge, Julie A., Fiona J. Qualls, Gordon H. Rodda. 2007. Reproductive Biology of the Brown Tree Snake, Boiga irregularis (Reptilia: Colubridae), during Colonization of Guam and Comparison with That in Their Native Range. Pacific Science, 61(2): 191-199.
Rodda, Gordon H., Julie A. Savidge 2007. Biology and Impacts of Pacific Island Invasive Species. 2. Boiga irregularis, the Brown Tree Snake (Reptilia: Colubridae). Pacific Science, 61 (3): 307-324.
D.F. Trembath, S. Fearn. 2008. Body sizes, activity times, food habits and reproduction of brown tree snakes (Boiga irregularis) (Serpentes: Colubridae) from tropical north Queensland, Australia. Australian Journal of Zoology 56: 173–178.
Brooks A. Kaiser, Kimberly M. Burnett 2010. Spatial economic analysis of early detection and rapid response strategies for an invasive species. Resource and Energy Economics 32 (4): 566-585.
Tyrrell, Claudine L., Michelle T. Christy, Gordon H. Rodda, Amy A. Yackel Adams, Aaron R. Ellingson, Julie Savidge, Kathy Dean-Bradley, Richard Bischof. 2009. Evaluation of trap capture in a geographically closed population of brown treesnakes on Guam. Journal of Applied Ecology 46: 128-135.
Mathies, Tom, Russel Scarpino, Brenna A. Levine, Craig Clark, and Julie A. Savidge. 2011. Excluding Nontarget Species from Brown Tree Snake, Boiga irregularis (Reptilia:Colubridae), Bait Stations: Experimental Tests of Station Design and Placement. Pacific Science 65(1): 41-57.
Wiles, G. J., Bart, J., Beck, R. E. and Aguon, C. F. 2003. Impacts of the Brown Tree Snake: Patterns of Decline and Species Persistence in Guam's Avifauna. Conservation Biology 17: 1350–1360.
Tarr, C. L. and Fleischer, R. C. 1999. Population boundaries and genetic diversity in the endangered Mariana crow (Corvus kubaryi). Molecular Ecology 8: 941–949.
Tomback, Diana F. 1986. Observations on the Behavior and Ecology of the Mariana Crow. The Condor 88 (3): 398-401.
Campbell, Steven R., Stephen P. Mackessy, Jennifer A. Clarke. 2008. Microhabitat Use by Brown Treesnakes (Boiga Irregularis): Effects of Moonlight and Prey. Journal of Herpetology 42(2): 246-250.
Kimberly M. Burnett, Sean D'Evelyn, Brooks A. Kaiser, Porntawee Nantamanasikarn, James A. Roumasset. 2008. Beyond the lamppost: Optimal prevention and control of the Brown Tree Snake in Hawaii, Ecological Economics, Volume 67 (1): 66-74.
Rodder, Dennis, Stefan Lotters. 2010. Potential Distribution of the Alien Invasive Brown Tree Snake, Boiga irregularis (Reptilia: Colubridae). Pacific Science, 64(1): 11-22.

Photo: By USNPS

Little Brown Bats & White Nose Fungus by Nora Tjossem
December 14, 2011 01:36 PM PST
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Did you hear that?
That was the sound of the little brown bat - Myotis lucifugus. They’re everywhere on summer nights, and sometimes if you’re lucky, you’ll get to catch a glimpse of one as it chases mosquitoes through the trees.

But go outside right now if you want to, because it’s possible that within the next sixteen years, you won’t be hearing more than a recording. The little brown bats of North America are fighting a losing battle against an enemy we call...

That’s right. Or, in the scientific world, “Geomyces destructans.” This cold-loving fungus has been ravaging bat caves throughout North America since 2006, wiping out an average of 73% of an infiltrated cave population.

How does a fungus take out three out of every four bats?

Picture this: It’s late October. You’re a bat, hanging upside down in preparation for winter. This means you’ve eaten your fill of summer insects, you’ve huddled together with your family members, and you’re ready to shut down for the long, cold Northeastern winter ahead. You enter what’s called “torpor” - your body temperature decreases, you are using less energy and fewer resources, and you wake up sleepily every few weeks to replenish.

However, your body is now incredibly vulnerable. This is when the fungus strikes, eroding the exposed skin on your ears and wing membranes. You have what is known as White-Nose Syndrome.

What does this mean?
It means your hibernation plan has been compromised. Your time out of torpor increases, the balance of your systems is disrupted, and you’re prone to starvation or dehydration. Your chances of living are slim, and you’re likely to end up among thousands of your colony members dead on the cave floor.

Little brown bats are the most common of bats in North America, but they are now facing a threat that could lead to their eradication in the Northeast in under two decades. This means that the children of my generation’s college students may never get to see a little brown bat in New England. Also, insect populations could vastly increase. An individual bat eats about 3 to 7 grams of insects per night - that’s about the amount of ground coffee required for your 8 oz morning cup. Think of that many mosquitoes instead!

Social animals, such as bats, elephants, dolphins, and humans, are especially prone to rapid-spreading disease. It’s easy to be content with the current status of bat populations, but if we don’t pay attention and focus our research efforts now, a disease that first appeared only five years ago could lead to the eradication of our friend the little brown bat.

Blehert D, Hicks A, Behr M, Meteyer C, Berlowski-Zier B, Buckles E, Coleman J, Darling S, Gargas A, Niver R, Okoniewski J, Rudd R, and Stone W. 2009. Bat White-Nose Syndrome: An Emerging Fungal Pathogen? Science 323 (5911):227.
FOLEY, J, CLIFFORD, D, CASTLE, K, CRYAN, P and OSTFELD, R. S. 2011. Investigating and Managing the Rapid Emergence of White-Nose Syndrome, a Novel, Fatal, Infectious Disease of Hibernating Bats. Conservation Biology 25: 223–231.
Frick W, Pollock J, Hicks A, Langwig K, Reynolds D, Turner G, Butchkoski C, and Kunz T. 2010. An Emerging Disease Causes Regional Population Collapse of a Common North American Bat Species. Science 329: 679.
Kerth G, Perony N, Schweitzer F. 2011. Bats are able to maintain long-term social relationships despite the high fission-fusion dynamics of their groups. The Royal Society 2011 Feb 9; doi: 10.1098/rspb.2010.2718.
Bats About Our Town. Greg Salxa. 7 Dec. 2011
Photo: Marvin Moriarty/USFWS

Crop's Wild Relatives: Maize and Teosinte by Dylan Sweetwood
December 14, 2011 03:39 PM PST
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The Relationship Between Maize and Teosinte
Dylan Sweetwood

You probably already know that maize, or corn, is one of the most culturally and commercially important crops in the world, with hundreds of applications in areas from agriculture to energy. But what you may not know is that teosinte, one of corn’s closest genetic relatives, is currently under threat of extinction. Then again, so are a lot of other plants—why is teosinte worth worrying about? My name is Dylan Sweetwood, and I’m going to talk about the relationship between maize and teosinte and why this relationship is important to preserve.

Humans have grown maize for thousands of years—so long, in fact, that it can no longer reproduce without human cultivation. This long history has resulted in a genetic bottleneck, which means that all modern varieties of corn are genetically indistinguishable. Traditionally, this was considered advantageous, but now scientists believe that genetic diversity is beneficial for crop persistence. Corn’s limited genetic toolkit makes it more susceptible to natural disasters like drought and climate change, which is a big problem for farmers.

Fortunately for the agricultural industry, teosinte, which is usually found growing on the edge of cornfields, hybridizes well with its domestic relative. Hybridization is when two related species swap genes, resulting in a genetic mixture. Maize and teosinte have hybridized naturally for millennia; by hybridizing the two selectively, it would be possible to breed new varieties of maize whose gene pools are diversified and strengthened by teosinte. These genes may offer resistance to natural stressors and sometimes even increase crop yield—something farmers would definitely be happy about.

Unfortunately, natural hybridization is risky. Because maize and teosinte have been hybridizing for so long, their hybrids usually have high fertility rates; farmers often consider these hybrids weeds and they exterminate them, which stops teosinte genes from being passed on to future generations of crop corn. As you might guess, infestation of maize-teosinte hybrids in and around cornfields is actually threatening teosinte because it dilutes the wild type. Teosinte also has a very narrow geographical range, limited to small populations in Central America; because of this, teosinte is more vulnerable in the face of environmental changes and invasive species. The small range of teosinte combined with genetic swamping has pushed this wild species to the brink of extinction.

Today, the teosinte population is less than half of what it was fifty years ago. Controlled hybridization of maize and teosinte could have a lot benefits, like increased hardiness and favorable crop yields. The same holds true of many common crops and their wild crop relatives, but considering how important corn is to humans—and anticipating how much more vital it will be in the future—teosinte preservation is an issue that requires immediate action. Thank you.

Haygood, Ralph, Anthony R. Ives, and David A. Andow. 2003. Consequences of Recurrent Gene Flow from Crops to Wild Relatives. Proceedings of the Royal Society B: Biological Sciences 270: 1879-886.

Wilkes, H. G. 1972. Maize and Its Wild Relatives. Science 177: 1071-077.

Album Credit

Where did the Dingo go? By Lauren Sweet
December 15, 2011 05:54 PM PST
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Hi I’m Lauren and your listening to “Where did the Dingo Go?”
We often think of Australia as a land hopping with kangaroos, wallabies, bilbies and other fuzzy critters. What most people don’t realize is that, despite this apparent diversity, in the last 2 centuries Australia has seen 19 of its unique mammal species become extinct (Johnson 2006) –that’s about half of all mammal extinctions worldwide in that period (Johnson et al. 2007). And Australia's mammals are still in great danger because of the slow demise of the wily dingo.
About 4000 years ago man brought the dingo to Australia. Since then, the dingo has gone from ancient companion to top predator(Ritchie & Johnson 2009).While you might think the Dingo is a pesky carnivore that eats livestock, gobbles up native animals and is generally the equivalent of the big bad wolf, the truth is that the dusty colored dingo is anything but bad. Since becoming top dog, dingoes have lived in relative harmony with the many small, rare Australian marsupials-you know, those cute mammals with pouches. This is mainly because dingoes are sparsely distributed and, because of a large body size, are specialized to hunt larger prey (Ritchie & Johnson 2009). To a dingo, a wallaby just doesn’t have enough meat on it to be as appetizing as a kangaroo. The same, however, cannot be said for the invasive red fox.
When Europeans introduced the red fox in 1855 for some recreational sporting (Dprt. of the Enviro. and Heritage (Australia) 2004) they could not have suspected that foxes would soon become the plague of Australia’s small mammals. In fact, foxes have been blamed for the extinction of many of Australia’s species. (Short 1998) (Johnson & VanDerWal 2009) (Johnson 2006)(Glen & Dickman 2005). The fox is a prey generalist, meaning he is not picky about what he eat. Rabbits, wallabies, birds—it all goes down the hatch. Foxes, because of their smaller size have more babies than dingos, more often (Dprt. of the Enviro. and Heritage (Australia) 2004) (Corbett 2004) and don’t need as much space per individual, so they can exist at high densities. Combine these three things—an undiscriminating appetite, lots of babies and the ability to pack many individuals into a small area-- and you can see how the fox is having a terribly negative effect on vulnerable ground dwelling marsupials (Ritchie & Johnson 2009).
Interestingly however, where dingoes exist, threatened marsupials are able to survive predation by foxes (Johnson et al. 2007) (Johnson & VanDerWal 2009). In fact, knowing where dingoes exist can be one of the best predictors of how well vulnerable species are doing (Wallach et al 2009) (Johnson et al. 2007). Turns out that the dingo is nowhere near the bad guy in this story. If anything he is the opposite, the good guy—protector of marsupials.
Why? Well, it turns out that dingoes play a very important role in culling fox populations. Dingoes actively attack foxes and, as a result of this persecution, foxes make a great efforts to avoid dingoes and dingo territory (Ritchie and Johnson 2009) Thus dingoes create a safety zone for the local small animal population(Ritchie & Johnson 2009) (Johnson and VanDerWal 2009).
Food webs are complicated and its important for us to understand that a top predator doesn’t effect only its prey but also impacts other predators and smaller animals that the apex carnivore doesn’t even directly associate with. In Australia, it is truly a dog-eat dog world—or in this case a dog-eat-fox.
Besides preserving Australia’s biodiversity, controlling the fox population also has significant economic impacts. The sheep industry in Australia produced 1/5 of the world’s wool in 2010. Yet, in some areas, foxes may kill up to 1/3 of lambs (Saunders 1995). And of course there is also the loss in ecotourism as more and more unique Australian species end up in the stomachs of foxes( Saunders 1995).
The dingo is as iconic to Australia as the wallaby, or the wombat and yet, despite the necessary role it play as protector of other iconic Australian mammals, the dingo is too often treated as a pest. Dingos are subjected to poisoning or otherwise exterminated and kept at low population levels (Johnson et all 2007) (Wallach et al. 2009). All of which hurts the dingo and those animals preyed upon by foxes. The dingo is a powerful tool in the saving of Australia’s fuzzy marsupials (Ritchie & Johnson 2009). But, dingoes are disappearing, and if they do, Australia will loose much more than just some wild dogs.

Thanks for listening

Cited Sources
Corbett, Laurie. 2004. Dingo. Canids: Foxes, Wolves, Jackals and Dogs. International Union for Conservation of Nature and Natural Resources.
Glen, Alistair S. and Dickman, Chris R. 2005. Complex interactions among mammalian carnivores in Australia, and their implications for wildlife management. Biological Review, 80: 387–401.
“Invasive species fact sheet: European red fox (Vulpes vulpes)”. Department of the Environment and Heritage (Australia). 2004.
Johnson, Chris N. 2006. Australia’s Mammal Extinctions: A 50 000 Year History. Cambridge University Press, Cambridge.
Johnson, Chris N., and VanDerWal, Jeremy. 2009. Evidence that dingoes limit abundance of a mesopredator in eastern Australian forests. Journal of Applied Ecology 46: 641–646.
Johnson, Chris N., Isaac, J.L. and Fisher, D.O. 2007. Rarity of a top predator triggers continent-wide collapse of mammal prey: dingoes and marsupials in Australia. Proceedings of the Royal Society B: Biological Sciences, 274: 341–346.
Ritchie, E. G. and Johnson, C. N. 2009. Predator interactions, mesopredator release and biodiversity conservation. Ecology Letters, 12: 982–998.
Saunders, Glen 1995. Managing Vertebrate Pests: Foxes. Canberra: A.G.P.S.
Short, Jeff. 1998. The extinction of rat-kangaroos (Marsupialiatongueotoroidae) in New South Wales, Australia. Biological Conservation 86.3: 365-377.
Wallach, Arian D., Murray, Brad R., O’Neill, Adam J. 2009. Can threatened species survive where the top predator is absent?. Biological Conservation, 142: 43-52.
Photo: Creative Commons: Henry Whitehead

An interview with Nicole Ruiz about orangutans
December 14, 2011 03:31 PM PST
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Bartholomew: Hey guys. So last week I took my family to the zoo where we watched a show about orangutans. I was a little upset to hear that they’re declining in numbers. Anyway, last night I met up with Nicole Ruiz, a Stanford student interested in orangutan conservation, and she let me in on the little things that make orangutans so special. Tune in to find out what I learned!


B: Hi Nicole, thanks for taking the time out to speak with me. So what can you tell me about orangutans? What makes them so special?

N: So I’d like to begin by giving you a little background of where they live. Wild orangs are located on either the island of Sumatra or Borneo. Sumatran orangutans are more critically endangered, though. They have a population of about 7000. Bornean orangutans have a population of about 50000. I don’t know if you know this, but orangutans are one of the great apes. This includes chimps, gorillas, bonobos, humans, and, of course, orangutans.

B: Wait--so are you telling me these animals are close relatives of humans?

N: Yeah it’s pretty amazing! Did you know that orangutans actually share approximately 97% of their DNA with us? Scientists first sequenced orangutan’s genome with a female Sumatran orang named Suzie.

B: No, I didn’t know that, but that’s amazing! I noticed how calm and quiet they were in the zoo, not at all like the chimps.

N: Great observation! Orangutans are extremely gentle and shy. They’re probably the gentlest great apes. Studies have shown that baby orangs have an exceptionally close attachment to their mothers. She spends 8 years non-stop teaching her offspring how to survive. So then after those 8 years, they’ll separate and start living in solidarity. I personally think that this special attachment makes orangutans unique and awesome.

B: Their offspring must learn a lot from their moms if they’re with them for 8 years, right?

N: They learn so much from their mothers, especially through cultural behaviors that are passed down from generation to generation.  Different orangs have different family traditions! This, in turn, creates different orangutan behavior and culture. If there are two orangutans that live on opposite sides of Borneo, they won’t have the same set of behaviors. This is just due to the way they’re brought up. This is the old nature vs. nuture story, just as in us humans!

B: I never knew that animals acted so similarly to humans.

N: Also remember that orangutans are important for more than just being similar to humans. Another unique feature is the color of their hair. You may have noticed that they’re red and orange. Other great apes are black and brown in color. They don’t have that nice color that orangutans have. But aside from their color, orangutans are important members of the tropical forests they are found in.  They help in forest regeneration. Since most of their diet consists of fruit, they end up spreading the fruits’ seeds via their feces. This actually helps grow more plants in their environment.

B: Well who knew that spreading feces could actually result in a very positive outcome! Well, when I learn about these animals I want to know what is making them threatened.

N: Two major problems that are affecting orangs are deforestation and illegal poaching. The more the forests are destroyed, the fewer orangs that can exist. There are groups, such as the Centre for Orangutan Protection, that are trying to stop deforestation. There definitely are laws in place to stop illegal capture or killing of orangs, but they are tough to enforce without adequate funding for patrols. 

B: That’s terrible, but all this makes me want to learn more and to take action.  Thanks so much for talking with me today, Nicole.


Campbell-Smith G, Campbell-Smith M, Singleton I, Linkie M (2011) Apes in Space: Saving an Imperilled Orangutan Population in Sumatra. PLoS ONE 6(2): e17210. doi:10.1371/journal.pone.0017210

—Changes in Orangutan Caloric Intake, Energy Balance, and Ketones in Response to Fluctuating Fruit Availability  Cheryl D. Knott Received June 3, 1997; revised February 25, 1998; accepted April 6, 1998 

—Chen, C.-C., Pei, K.-C., Yang, C.-M., Kuo, M.-D., Wong, S.-T., Kuo, S.-C. and Lin, F.-G. (2011), A possible case of hantavirus infection in a Borneo orangutan and its conservation implication. Journal of Medical Primatology, 40: 2–5. doi: 10.1111/j.1600-0684.2010.00442.x

—Meijaard E, Welsh A, Ancrenaz M, Wich S, Nijman V, et al. (2010) Declining Orangutan Encounter Rates from Wallace to the Present Suggest the Species Was Once More Abundant. PLoS ONE 5(8): e12042. doi:10.1371/journal.pone.0012042

— "Orangutan." Honolulu Zoo. N.p., n.d. Web. 1 Dec 2011. <http://www.honoluluzoo.org/orangutan.htm&gt;

—PERKINS, L. (1998), Conservation and management of orang-utans Pongo pygmaeus ssp. International Zoo Yearbook, 36: 109–112. doi: 10.1111/j.1748-1090.1998.tb02891.x

Serge A. Wich, Erik Meijaard, Andrew J. Marshall, Simon Husson, Marc Ancrenaz, Robert C. Lacy, Carel P. van Schaik, Jito Sugardjito, Togu Simorangkir, Kathy Traylor-Holzer, Matt Doughty, Jatna Supriatna, Rona Dennis, Melvin Gumal, Cheryl D. Knott and Ian Singleton (2008). Distribution and conservation status of the orang-utan ( Pongo spp.) on Borneo and Sumatra: how many remain?. Oryx, 42 , pp 329-339 doi:10.1017/S003060530800197X

—Sumatran Orangutan Society. N.p., n.d. Web. 1 Dec 2011. <http://www.orangutans-sos.org/orangutans/crisis&gt;

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