The Social Cost Of Carbon
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A state-of-the-art report that brings together some of the best minds in environmental policy and economics recommends a new way of evaluating the social costs of carbon pollution to keep up with the best available science. Living On Earth’s Helen Palmer and Professor Billy Pizer, an economist at the Duke University Sanford School of Public Policy discussed the changes and why social cost evaluations are crucial to tackling carbon pollution. (06:20)
Beyond The Headlines/ Peter Dykstra
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Peter Dykstra and host Helen Palmer examine proposed legislation in Wyoming that would ensure renewable energy cannot be used in the state for power generation, and the reluctance of the EPA to pay compensation for a disastrous mine waste spill. Also in environmental history, they note a trio of aviation firsts that include one mishap that might have left a hydrogen bomb underneath Greenland’s melting ice. (04:45)
Small Whale Entangled in Big Threat
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The vaquita, the world’s smallest whale, lives only in Mexico’s Gulf of California and is critically endangered, due to illegal fishing. Now the Center for Biological Diversity plans legal action against the U.S. government for its failure to sanction Mexico for not stopping the poaching. Living on Earth’s Steve Curwood spoke with CBD’s Sarah Uhlemann about the threats vaquita face, and the legislative efforts to save them. (10:05)
City Lizards Adapt Fast to Urban Living
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For anole lizards living in Puerto Rican cities, the slickness of walls and windows poses a challenge to creatures that evolved on rocks and trees. Yet they are fast adapting to grip well on smooth surfaces. Living on Earth’s Helen Palmer visited anole researcher Kristin Winchell in her lab at the University of Massachusetts Boston to see how these little reptiles are coping with the built environment. (11:30)
Figs: The Vital Forest Species
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Fig trees are one of the world’s most diverse groups of plants, and have fed people and thousands of other species for millennia. Mike Shanahan, author of Gods, Wasps, and Stranglers: The Secret History and Redemptive Future of Fig Trees, tells Living on Earth’s Helen Palmer about the unique ecology, mythology and cultural value of fig trees, and how they can help us care for and protect nature. (15:00)
HOST: Helen Palmer
GUESTS: Billy Pizer, Sarah Uhlemann, Kristin Winchell, Mike Shanahan
REPORTERS: Peter Dykstra
PALMER: From Public Radio International, this is Living on Earth.
PALMER: I'm Helen Palmer in for Steve Curwood.
Rising seas, falling crop yields, more air conditioning. Rethinking how to count the costs of global warming and the benefits of cutting carbon.
PIZER: When we do cost-benefit analysis, the goal of government policy should be to try and improve welfare and there needs to be a way to do that mechanically and the social cost of carbon is the way that you do that. It's not a Republican or a Democratic idea -- It's an economic idea.
PALMER: But the incoming Republican administration is skeptical. Also, evolution in action in lizards in Puerto Rican cities.
WINCHELL: So we found that in the urban habitats, the animals actually do have more of these scales on their toes, and they also have larger toe pads. These things have to do with increased adherence to give them a really strong grip to perfectly smooth surfaces.
PALMER: That and more this week, on Living on Earth. Stick around.
[NEWSBREAK MUSIC: Boards Of Canada “Zoetrope” from “In A Beautiful Place Out In The Country” (Warp Records 2000)]
PALMER: From the Jennifer and Ted Stanley Studios at the University of Massachusetts, Boston and PRI, this is Living on Earth. I’m Helen Palmer in for Steve Curwood. 2016 was the hottest year on record. So was 2015, and 2014 before it, according the National Oceanic and Atmospheric Administration and other agencies. And NOAA blames human activity for this run of heat records, which gives urgency to attempts to cut greenhouse gas emissions. Rules and Regulations do this at the U.S. federal level and a new report from the National Academies of Sciences updates an important policy tool authorities rely on to craft them. It’s the social cost of carbon, which quantifies the costs of climate change damage, and the social benefits of cutting emissions. The report is a collaboration of experts in many different disciplines, from climate science to economics to public policy. Joining us to clarify the new thinking is committee member Billy Pizer of the Duke University Sanford School of Public Policy. Professor Pizer, welcome to Living on Earth.
PIZER: Thank you.
PALMER: So, first of all, tell me what is the social cost of carbon? What does it attempt to quantify?
PIZER: Well, it attempts to capture the dollar value associated with reducing a ton of carbon dioxide, a pollutant associated with burning fossil fuels.
PALMER: So basically, it attempts to say how much you would save if you didn't burn that ton of carbon?
PIZER: Right. How much you would save in terms of avoided human health consequences or flooding from climate change or heat waves. You could just make a long list of all the consequences associated with climate change, and it tries to calculate what’s the incremental reduction of those activities or those impacts associated with reducing emissions by a single ton.
PALMER: And you have just come up with a new report -- or you're one of the authors of the new National Academies report that looks at the way this figure is calculated and says there's a better way. What was wrong with how it was calculated before?
PIZER: Well, there was nothing really wrong in the sense that the government used the best available information it had at the time that it constructed this estimate. The original estimate was constructed in 2010, and then there was a revision in 2013. What the report does is it looks at what it did and it looks at the state of the science and it says, well, there's actually a lot of stuff that we know that hasn't yet been put into these sorts of models. And so it really calls for improving the models by bringing in the very best science that exists right now into the estimates. And there's just been a lot more research done on effect of heat waves on mortality, and flooding, on crops, things like that. And that has not yet made its way into these integrated assessment models that these three scholars who've added it up previously have done.
PALMER: So, the plan is to actually count the cost of the amount of, for instance, reduced agricultural product, as a result of climate change?
PIZER: Exactly. And what the report recommends is rather than leaning on these three existing models necessarily that they look for updates and perhaps the authors, the scholars themselves who have these three models will perform all these updates, or perhaps the government will commission its own model, but there needs to be a model for government. Or the recommendation is really for a model for government analysis, which is constantly updated with the best science.
PALMER: How has it actually been used already in government regulation?
PIZER: Wow. Well, it's been used in over 100 different government cost-benefit analyses. The one that is most famous, or infamous, is the administration's Clean Power Plan which was a regulation to reduce carbon dioxide emissions from power plants. In that regulation, the social cost of carbon figured quite prominently because it was the main purpose of that regulation.
PALMER: Now, a memo from the energy department transition leader Thomas Pyle suggests that the incoming Trump administration might consider lowering the social cost value or getting rid of it completely. What impact would it have if they decided to completely get rid of the social cost of carbon as a calculation in the regulations they're making?
PIZER: Well, I think it would be problematic. I mean, generally when we do cost-benefit analysis, the goal of government policy should be to try to improve welfare for the American people and for people around the world, and there needs to be a way to do that mechanically, and the social cost of carbon is the way that you do that. It's not a Republican or Democratic idea. It's an economic idea.
PALMER: I gathered the current value is about $36 per ton of CO2.
PALMER: How do you think your new calculations or the new suggestions about calculating the social cost of carbon will affect it?
PIZER: That's a great question. I don't know that the committee had a particular idea about that. There's certainly reasons to think that new estimates might come in high. There are other reasons that it might come in low. So, I think the main point is that we wanted to see the calculations, particularly the damages and the impacts in a transparent, scientifically-based way that was more understandable and kind of more rational going forward.
PALMER: By and large, how responsive has Congress been to the whole idea of the social cost of carbon and including it in these regulations?
PIZER: Well, you know, we live in a highly polarized time in our political environment right now. I would say that -- and I haven't been on the Hill briefing people on this, so I'm not intimately familiar -- but my more general experience suggests that people who care about good, rational, economically-driven policy like the idea of a social cost of carbon. They may quibble with some of the assumptions like the global damages versus U.S. focused damages or some of these important assumptions that reasonable people are going to disagree about, but they don't disagree on the idea that when we do regulations we ought to be motivated by balancing costs and benefits.
PALMER: Professor Billy Pizer teaches at the Duke University Sanford School of Public Policy. Thanks very much.
PIZER: Thank you. I've really enjoyed it.
- The full 2016 social cost of carbon report
- Andrew Revkin for ProPublica: “Will Trump’s Climate Team Accept Any ‘Social Cost of Carbon’?”
- Yale Climate Connections explains the social cost of carbon
- Billy Pizer Duke University faculty bio
PALMER: Off to Conyers, Georgia now to find Peter Dykstra of DailyClimate.org and Environmental Health News, EHN.org. He’s here with some insights from beyond the headlines. Hi Peter!
DYKSTRA: Hi Helen. With all the attention on Washington D.C. this week, let’s just transport ourselves a couple of thousand miles away from there and ponder a strange development in the Wyoming legislature. A bill in the Wyoming Senate would pretty much outlaw the use of wind and solar energy by the state’s electric utilities. If the bill becomes law, power companies would pay a fine to the state for using any energy from large-scale wind or solar projects.
PALMER: Hmmmm ... do you think might just have something to do with the fact that Wyoming is the largest coal-producing state in the country?
DYKSTRA: It just might. While other states are setting up renewable energy standards, Wyoming might be headed to an anti-renewable standard. It’s no secret that the demand for coal is shrinking, though it’s still mighty popular in Wyoming, where coal produces almost 90 percent of the state’s electricity. Critics say the bill would lash the state’s fortunes to a declining industry, and in any event, guaranteeing a strong market for coal in the least-populous state in America isn’t going to put a dent in the coal industry’s sagging prospects.
PALMER: Well, how likely is this to become law?
DYKSTRA: That’s not clear, but it’s worth noting that a state senator from Gillette, that’s Wyoming’s coal capital, says he’s not sponsoring the bill because Wyoming’s sparse population can’t even use enough coal to make a difference.
PALMER: Interesting development. What’s next?
DYKSTRA: Well, the EPA doesn’t exactly need to find new reasons for rural America to hate what it does. Or in this case, what it doesn’t do. Remember that accidental mine-waste spill that turned the Animas River in Colorado and New Mexico the color of a school bus in 2015?
PALMER: Yes, I do. But the EPA was actually trying to do something really good; it was trying to reduce the risk of a mine waste spill and ended up causing that very thing that it was trying to prevent.
DYKSTRA: Right and mine waste, including cadmium, lead and arsenic found its way into the river. More than a billion dollars in damage claims came in, but the agency says it’s not going to pay any of them, citing the Federal Tort Claims Act, which shields some government actions from damage claims. Senators and Congressman from the area are outraged, including some Democrats who normally support the EPA and its mission.
PALMER: Well, it does seem a bit odd that an agency whose mission includes making polluters pay for damage doesn’t want to pay for its own pollution.
DYKSTRA: Right. The 73 claimants include farmers, ranchers, recreational interests and the Navajo Nation and they have six months to take the Feds to court to try and get compensated. For its part, EPA says some of the damage claims may be bogus, and they add that a few are outlandishly large.
PALMER: Well, as you said, the EPA is one agency that doesn’t have to go out of its way to make itself unpopular – and the prospective head of the agency doesn’t love it either. Let’s take our weekly stroll through environmental history, shall we?
DYKSTRA: Surely. I’ve got a tripleheader of aircraft-related anniversaries. This week in 1970, the first commercial flight of the Boeing 747 -- the jumbo jet -- took off from New York’s Kennedy Airport and landed at London’s Heathrow Airport six and a half hours later, delivering over 400 passengers and setting new standards for airborne luxury.
PALMER: I believe it also set new standards for fuel consumption as well.
DYKSTRA: They don’t measure it in miles per gallon. It’s five gallons per mile according to Boeing, which is next to nothing compared to the plane that was introduced almost six years later to the day, the Concorde. Flying at supersonic speed, the Concorde could make the New York-London run in three and a half hours, burning fuel at a rate about 40 percent faster than the 747. Environmentalists fought the Concorde’s introduction, fearing two things that never actually happened -- massive bird kills and destruction of the ozone layer.
PALMER: Well, we did find some other ways to damage the ozone layer.
DYKSTRA: True enough. But high fuel costs and a catastrophic accident in the year 2000 helped end the Concorde’s run. Its last flight was in 2003. Got time for one more plane truth?
PALMER: Ooh. Yes, go ahead.
DYKSTRA: This week in 1968, a cabin fire aboard US Air Force B-52 forced the plane to ditch while trying an emergency landing at Thule Air Base in northern Greenland. One of the seven crewmembers died, but the plane’s payload was lost -- four hydrogen bombs. In the search that followed, the Pentagon said that all of the bombs were “accounted for.” But classified documents released years later suggest that “accounted for” didn’t mean they were all recovered. There’s speculation, but no admission, that one of the four H-bombs is still out there, possibly beneath the unstable ice along Greenland’s shores.
PALMER: Well, that certainly would be a vey nice discovery as the Arctic ice melts away. Peter Dykstra is with Environmental Health News, that’s EHN.org, and DailyClimate.org. And thanks very much for talking to us, Peter. Talk to you soon.
DYKSTRA: Thanks a lot, Helen. Talk to you soon.
PALMER: And there’s more on these stories on our website, LOE.org.
- InsideClimate News: “Wyoming Bill Would All But Outlaw Clean Energy By Preventing Utilities From Using It”
- USA Today: “EPA won’t pay claims in mine spill that released 3M gallons of toxic water”
- SeattlePi: “First Boeing 747 rolled out 47 years ago”
- Concorde FAQ
- ABC News: “Lost U.S. Nuke Off Greenland Base Site?”
[MUSIC: Daro Natraj, “Na Yella Bo,” on Deccan Dance, traditional West African/arr. Scarff, Galloping Goat Productions]
PALMER: Coming up ... a bid to save one of the world’s most endangered whales. Stay tuned to Living on Earth.
ANNOUNCER1: Support for Living on Earth comes from the Gordon and Betty Moore Foundation, and from a friend of Sailors for the Sea, working with boaters to restore ocean health.
[CUTAWAY MUSIC: Darol Anger and Mike Marshall, “Dolphins” on Chiaroscuro, Darol Anger, BMG Music]
PALMER: It’s Living on Earth, I’m Helen Palmer, in for Steve Curwood. The world’s smallest whale, the Vaquita, lives only in the Gulf of California off Mexico’s Northwest coast. It’s critically endangered, and now illegal fishing is helping drive it towards extinction. On January 5, the US-based Center for Biological Diversity issued an official warning of legal action to the US government, asking it to put pressure on Mexico to control the poaching. To find out more, Living on Earth host Steve Curwood called up Sarah Uhlemann, the International Program Director for the Center for Biological Diversity.
CURWOOD: First, just explain to us what is the vaquita whale.
UHLEMANN: So, a vaquita is the world's smallest porpoise. It's tiny. It's only about five feet long. It's gray with some black splotches around its mouth and its eyes, giving it what some people refer to as a bit of a Goth look, but I find it a bit unkind. It really lives only in one place on Earth, and that is in Mexico's Gulf of California on the very very top northern corner. This was a species that was only first identified by scientists back in the 1950’s -- it's pretty new to science. But scientists believe that even since its identification in the 50’s it has been declining.
CURWOOD: Now, why is the vaquita so important to the Gulf of California ecosystem and how exactly is it threatened?
UHLEMANN: So, vaquita are the rarest porpoise in the world. They're evasive. They're very shy. They swim away from boats. They consume a lot of fish. They are just an integral part of a very very amazing ecosystem. Jacques Cousteau called this habitat, the Gulf of California, "the aquarium of the world," and this is one of the key species in the aquarium of the world. vaquita face really one threat, and really one threat, and that is entanglement in fishing gear, a particular kind of fishing gear called gillnet gear. So gillnet gear is essentially two buoys that are up on the surface and the line that runs in between him and then the net that sort of hangs down below. Gillnets are very effective at capturing whatever fish a fisherman is targeting. But they are unfortunately also very effective at capturing pretty much anything that swims by including, unfortunately, the vaquita. vaquita get wrapped up in the net and they, of course, need to breathe, but they aren't able to get up to the surface and so they drown. It's a pretty rough way to go if you're if a vaquita.
CURWOOD: So, just how many of these vaquita are getting caught in gillnets by fisherpeople?
UHLEMANN: Well, we're not 100 percent sure, but we know that there's a lot. So, for about 30 years, we know that vaquita were getting caught in gillnet gear in trying to target shrimp. The population declined and declined until about 2008 when we knew there were only about 250 vaquita left. That's really small. Unfortunately, for the vaquita in 2011 there was a huge surge in fishing for another fish called the totoaba. totoaba is an enormous fish. It's five feet long, so actually just about the same size as a vaquita. It is in demand in China for its swim bladder, which is this organ that helps the fish stay afloat essentially. People in China believe ... some people in China believe that the bladder when it's dried and then reconstituted into a soup, it a can improve fertility and improve skin tone. Of course, there's no scientific evidence to support that, but nonetheless, totoaba bladders are in enormous demand. totoaba bladders regularly sell for about 14,000 U.S. dollars.
CURWOOD: Oh my.
UHLEMANN: And some of the really really big -- you know -- great bladders can sell for up to 50,000 dollars a piece. These are insanely lucrative fish. They are also, as you can imagine, endangered, and fishing for them is illegal in Mexico and trade of them internationally is entirely banned. But, because of that price there's so much totoaba fishing going on in Mexico and unfortunately to catch totoaba, you use a gillnet which is exactly what vaquita get entangled in.
CURWOOD: And so, this is all going on in Mexico, Sarah.
CURWOOD: Why are you taking the first steps in a lawsuit against the United States government to protect the vaquita?
UHLEMANN: Well, I think everyone acknowledges that ultimately the fate of the vaquita lies in the hands of the Mexican government. It's a Mexican species and Mexico needs to get ahold of its Totoaba poaching problem. But the U.S. also has an important part to play. It wields a really heavy hammer. So there is a law on the books in the United States called the Pelly Amendment, and this law says that at any time the U.S. government finds that any nation is violating a wildlife treaty, that it can certify that nation, that is formally notify the nation, and if a nation is certified, then the President can sanction the country, so usually through embargoes or a ban on imports of some kind of wildlife product.
So, back in 2014, my organization filed a petition requesting the government to certify Mexico for violating the CITES treaty, this is the Convention on International Trade in Endangered Species, it governs trade and imperiled species. Both the Totoaba and the vaquita are protected under this treaty. So, argue that Mexico is failing to enforce the ban on trade in Totoaba, and thus is violating the CITES treaty. Now, if the U.S. government does certify Mexico for these violations, which we hope that they will, President-elect Trump will have the authority to sanction Mexico. So the opportunity to embargo products, likely shrimp from Mexico, until Mexico can solve this problem, until it can get the gillnets out of the water.
CURWOOD: But so far you're saying the outgoing Obama administration has been unresponsive, which is why you're taking these first steps to bring them in to court. What do they say when they don't respond to your request that they intervene here.
UHLEMANN: Well, so we filed our petition two-and-a-half years ago. We've had a number of meetings with the Obama administration. They understand that there's a problem and the U.S. government has been working to push Mexico, and we understand that they've been using our petition and this threat in their conversations with Mexico to try to get Mexico to act. We understand that the agencies will soon be responding to the petition and that we need it to happen soon. The reality is that there are only 30 vaquita left on Earth, and if we don't act now, right now, we will lose the species forever.
CURWOOD: Thirty vaquita only left on the planet.
UHLEMANN: Thirty. Yeah, so scientists thought that there were about 60 in 2015 and there was decline of about 50 percent in 2016 alone. That is just a shocking level of decline. If declines continue, this species will be functionally extinct in two years.
CURWOOD: To what extent have you dealt with the Mexican government directly about this problem, and what has their response been?
UHLEMANN: So, conservation groups like mine have been pushing the Mexican government for years to take action. And for about 20 years, Mexico has been proclaiming that it is taking action. It's announced various sanctuaries and various refuges and various measures, but every single time Mexico makes these announcements, it fails to follow through. It maybe enforces for couple years, but then the fishing goes back up and illegal activity goes back up. We really strongly pressured the Mexican government back in 2015 to take action and it did. It announced publicly that it would close the entire vaquita habitat to gillnets and it would increase enforcement for totoaba poaching. We were so hopeful that this would be the answer. Unfortunately, a lot of new evidence shows that the enforcement just isn't happening. Drug cartels are becoming involved in the totoaba trade because it's so lucrative, and the Mexican government doesn't have the will or the finances right now to really take the action that it needs to. But it has to step up or we lose this species forever.
CURWOOD: And how many of these are in captivity? Some cetaceans don't much like captivity and won't thrive there. What about the vaquitas?
UHLEMANN: Yeah, there are no vaquita currently in captivity in fact, as far as I know no one has ever tried to take a vaquita into captivity. The Mexican government recently announced plans to capture at least some of the remaining vaquita, potentially all of the remaining vaquita to take them into what they're referring to as “sanctuary”. So, not to take them into Sea World or anything like that, but to put them in at sea pens, so basically netted enclosures within the Gulf of California. And the ideas is not keep them permanently, but to hold them in there temporarily until Mexico can get its gillnet problem under control.
CURWOOD: So, we understand the Mexican government is talking about asking the US Navy to bring in trained dolphins to help save the species. What you know about that, and how would that work.
UHLEMANN: Yeah, so that's sort of an interesting sideline to the situation. I think many of your listeners would be surprised to learn that the US has what are essentially working dolphins. These dolphins are trained to do a number of things, but primarily to detect underwater explosives. So the plan is not firm yet, but as I understand Mexico has asked the US Navy to bring its dolphins down to help the, either find the vaquitas initially or potentially once they are found to help the scientists track the vaquita as they try to capture the animals. We are hopeful that if the United States does send its navy dolphins down there - obviously that is controversial - that having a big US Navy boat on the Mexican waters will be a natural deterrent to Totoaba poaching, and that the U.S. Navy will offer its assistance in actual enforcement on the water.
CURWOOD: So, of course, with so little known about the vaquita, we don't know how they'll respond. What breed of dolphins? They're bottlenose, huh?
UHLEMANN: Yes, I believe so. No, we don't know exactly how the vaquita responds. The reality is we don't know how the vaquita are going to respond to capture. It is undoubtedly a risky situation, but we are down to the last thirty vaquita left and we are in desperate straits and that's the reality. I will say that the scientists who are planning to conduct this captivity or sanctuary plan, they didn't come to this conclusion easily. These are folks who have worked to save the vaquita. Some have committed their entire lives to saving the vaquita. But they recognize that we have to buy time, that if vaquita remain in their natural habitat, they're going to disappear. We really don't have any choices at this point.
CURWOOD: Well, I want to thank you for taking the time with us today. Sarah Uhlemann is the International Program Director for the Center for Biological Diversity. Thanks so much.
UHLEMANN: Thanks so much, Steve.
PALMER: Sarah Uhlemann, Speaking with Living on Earth host Steve Curwood.
- A deceased vaquita killed by a gillnet used for catching totoaba. (Photo: Omar Vidal / NOAA Fisheries West Coast, Flickr CC BY-NC-ND 2.0)
- Center for Biological Diversity updates on the status of the vaquita
- Center for Biological Diversity press release for the new lawsuit against the federal government
- Short film by Wild Lens on the vaquita, “Souls of the Vermillion Sea: Searching for the Vaquita”
[MUSIC: Darol Anger and Mike Marshall, “Dolphins” on Chiaroscuro, Darol Anger, BMG Music]
PALMER: Now we think of evolution as a matter of gradual changes over many generations, but that’s not always the case. Indeed, there are creatures that seem to be able to change aspects of their anatomy very speedily, and a case in point is some small lizards that live in Puerto Rico. An Associate Professor of Biology [Correction: PhD candidate] at UMass Boston is documenting these fast-evolving lizards, and I visited her lab on campus.
WINCHELL: My name is Kristin Winchell, and I work on urban ecology and evolution of Anolis lizards. They're a group of neo-tropical lizards. There is around 400 species of them throughout Central, South America and the Caribbean. Of those 400 or so species, there our about 100 that live in the Caribbean Islands, most of those are endemic -- only found on one island or chain of islands. I study a particular species from Puerto Rico, the Crested Anole, Anolis Cristatellus.
PALMER: What do they actually look like?
WINCHELL: So, I actually have some specimens here in this jar.
PALMER: Gosh, there are dozens in here.
WINCHELL: Yeah, these animals were part of a breeding experiment we did. So these are wild-caught individuals. They're all adult males from an urban and a natural population. You can see they're about four inches long from head to their hips. They also have a long tail after that that can be about as long as their body size.
PALMER: They're cute things. I'm interested, they look quite different. There's some with stripes down their backs and some with sort of like a pattern of blobs down their backs.
WINCHELL: Yes, so there's actually a very large amount of variation in patterning and coloration in Anolis and particularly in the species. But the males and females will have chevron patterns and modeled patterns on their backs and some just have a simple stripe, and they also have this dewlap which is a flap of skin on their throat and that dewlap is orange and yellow, and it is different in every species. And it functions to tell other animals, ‘hey I'm of your species’, or ‘hey I'm not of your species.’
PALMER: Which particular populations of Crested Anoles have you been studying and what have you been finding?
WINCHELL: So, I've actually works pretty extensively across the islands. My first studies were up in San Juan one kind of the northeast there.
PALMER: So, that's the capital.
WINCHELL: That's the capital. It's the largest city in Puerto Rico, and one of the largest cities in the Caribbean. It has a metropolitan population of over two million people. So, it's a really really substantially urbanized area. And actually there's very little natural forest there so it makes it a difficult place to do this type of study because you need to have both natural and urban habitats to compare animals. So, in San Juan, there's really only a couple of forests that you can look at. Most of my research the past couple of years has been in the city of Arecibo, which is up on the north coast there. It's a slightly smaller city, but it is an old city and it does have pretty sprawling urbanization there. I've also done some work in Mayaguez on the west coast and then Ponce on the south coast.
PALMER: So, you've done work in all these cities around there, and what have you exactly been looking at and what are you finding?
WINCHELL: I've been looking at how animal lizards are adapting to humans, and we set out with the idea that the Anole lizards that are persisting in these urban habitats, they are subject to natural selection pressures that exist in these habitats. And so, we looked it what we knew about their morphology and how that relates to the habitat, and how that's shifted in natural settings when habitats are modified, and came up with a set of hypotheses of what traits might be changing in this new setting and why. And so, we set out looking specifically at the toepads and the limbs, the limb length, in the urban areas with the hypothesis that in urban areas they tend to be perching on things like walls that are very broad. The habitats tend to be very open and they have to run across very large areas. And they're perching on things that are very different from a tree. If you think about a painted wall, it's much smoother and much harder than a tree trunk, and so we expected that there might be a shift in these functionally relevant traits.
PALMER: So, basically, if you’re running up a wall it's much more slippery than if say you're running up a tree.
WINCHELL: Exactly. Yeah, these lizards, they'll have a toepad that has these unique scales on them that we call lamellae. Basically, they look like folds or flaps of skin, but they are actually specialized scales that have these microscopic hair called cetae on them that interact at a microscopic level with the surface to give them a really strong grip to perfectly smooth services. So, they can climb up these smooth surfaces without the use of claws.
PALMER: Wow. That's clever. Do you have some pictures here?
WINCHELL: I do. So, I pulled up a picture here. This is the rear toepad of an Anolis that I measured, and when we take these photos we use just a high-resolution flatbed scanner. We place the animal on that and just scan it like you make a copy, and you can see here all of the little scales, and we can count the number of scales ... one, two, three, four, five ... all the way down until the toepad ends.
PALMER: It's very clear to see there how these scales sort of overlap each other.
WINCHELL: Yeah, so these lamellae, these scales function by increasing the surface area contact with the surface. And so each one of these little flaps because there's so many of them allow the toepad to kind of mold around the surface and really make as much contact as possible so those cetae can engage and increase its adherence.
PALMER: The cetae?? are the...
WINCHELL: The microscopic hairs. Yes.
PALMER: So you've been looking at these things and measuring these things. So, what have you found?
WINCHELL: So we found that in the urban habitats the animals actually do you have more of these scales on their toes and they'll have larger toe pads, and so this was in line with what we predicted because these things have to do with increased adherance. We believe we're seeing selection towards larger toe pads and more lamellae.
PALMER: So, how fast is this change happening?
WINCHELL: So, Anoles can reproduce year-round, and they can reproduce when they're about eight months old I'd say, based off of my studies. So you get really quick generation times, and this is a key factor in any rapid adaptation study because you want an animal that's producing offspring quickly. And so, some of the urban areas I've looked at are only 30, 40 years old, so it seems like not that long of a time, but if you think about that in lizard generations that can be a hundred or more lizard for generations.
PALMER: So you can't actually say exactly how fast this is happening. You can only say that it can't be slower than about 30 years.
WINCHELL: Yes, that's correct. The youngest populations we've studied have not been exposed to urbanization for more than 30, 40 years. So, it definitely is happening on that rapid of a time scale at least.
PALMER: And what's the mechanism for this happening, do you think?
WINCHELL: Well, so this is something that we've tried to address from a number of different perspectives. It makes sense that natural selection is shaping these phenotypes, these characteristics, but natural selection is inherently difficult to measure. What we do know is that there are these differences in urban areas with the animals having the larger toepads and longer limbs, and we do know that those have fitness consequences. We're working on some performance studies now in which we are looking at whether or not these phenotypes are associated with improved sprint performance on smooth urban substrates, and we're hypothesizing that these animals that have the larger toepads and longer limbs are going to be better able to perform in these types of habitats.
PALMER: So, basically, you're going to have Anolis races up the glass?
WINCHELL: [LAUGHS] Yes, actually we did have our own little Anolis Grand Prix during the summer where we raced animals up various tracks: metal, painted concrete, bark. We have over 1,000 videos of Anolis running in slow motion up racetracks.
PALMER: [LAUGHS] So, longer limbs, more scales on feet. Any other changes that you're seeing?
WINCHELL: Yeah, so we have seen as well shifts in their thermal tolerance. The urban animals - and this is very much a work in progress -- but the urban animals do seem to be able to tolerate higher temperatures. And so, that's really interesting, and we're also looking at the gene expression patterns behind that as well.
PALMER: So, why did you focus on this particular species?
WINCHELL: So, Anolis cristatellus is the most common species of Anole in Puerto Rico, and so it made sense to focus on the most abundant animal and they're also the one that is consistently found in urban areas. There's a couple of other species that you'll occasionally see in urban areas, but this is the one that is using the buildings, that's perching on houses, that's going inside and eating food scraps. This is the urban synanthrope, if you will. It's the one that is really thriving in the urban areas.
PALMER: So you've noticed differences in the urban species of this particular lizard. Is this common that there are changes in other urban spaces?
WINCHELL: So, for Anoles, we don't know yet, and this is a topic of future research I'm hoping to address. There are many Anoles that use urban habitats, and we're currently working on a project to try and understand why some species thrive in urban areas while others are merely tolerant and some stay out of it entirely. Outside of the world of Anoles, there are some people who have been looking at adoptive shifts in animals in urban areas and yeah people have found that there are shifts in thermal physiology in ants. There's some researchers in New York who are doing some really great work on the birds and the rats living in New York City, and they're finding some very interesting things there looking at the genomic aspect of urban tolerance. If you were to look at all animals in urban areas, you'd probably start to see some trends, especially at the genomic level of shifts in the ability to tolerate stress and tolerate heat and tolerate noise perhaps.
PALMER: Tolerate people.
WINCHELL: Tolerate people. Anything that you look at with an animal. With frogs they've found shifts behaviorally adjusting the pitch and cadence of their calls because when they sing regularly you can't hear them over the traffic noise and traffic embankments turn out to be pretty decent frog habitat. Behavioral adaptation shouldn't be discounted just because it's not genetically based. Behavioral adaptation is a really interesting part of the story because if the first animal that gets to an urban area can't tolerate heat, well, if it stays in the sun all day, it's definitely not going to pass on its genes. But you know maybe after a few generations, you'll get some animals that can tolerate hotter and hotter, and maybe they don't have to stay in the shadows so much. And so this behavioral adaptation of using a habitat differently or adjusting their communication can set the stage for future genetic change.
PALMER: Well, Kristin Winchell. Thank you very much for welcoming me into your lab and showing me all these interesting things.
WINCHELL: Thank you very much.
PALMER: You’ll find pictures and links at our website, LOE.org.
PALMER: Coming up ... mythology, biology and ecology. The remarkable fig tree has it all. That’s just ahead here on Living on Earth. Stay tuned.
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[CUTAWAY MUSIC: Ralph Moore, “Episode From a Village Dance” on Images, Donald Brown, Landmark Records]
PALMER: It’s Living on Earth, I’m Helen Palmer in for Steve Curwood. Every man sitting under his own fig tree is a Biblical vision of peace and prosperity, and it’s not just a fantasy. Figs have fed people for millenia, and they’ve developed complex partnerships with animals, insects, and plants. They’re also prominent in culture and mythology. And they might even have the potential to help shape our future, says author Mike Shanahan. In his new book, “Gods, Wasps and Stranglers: The Secret History and Redemptive Future of Fig Trees", Shanahan shares stories from the days of his field work studying rainforest fig trees, and explains their unique place on the tree of life.
SHANAHAN: Well, they're really fascinating plants. They've been around on the planet for about 80 million years, so they lived when the giant dinosaurs were still roaming around, and they have a really special relationship with some tiny wasps that pollinate their flowers. And each of the fig species, and there is something like 750 different species of figs, each of them has its own wasps that pollinate the flowers, and the flower are found inside the figs. And the wasps can only breed in those flowers, so they have a very tight relationship. Each one depends utterly on the other.
PALMER: So, does this means that when we eat figs, we're eating wasps?
SHANAHAN: In some cases maybe yes, but often not because the wasps often have departed from the figs before we get to eat them, and some of the edible varieties that we eat are actually species that farmers have developed over many thousands of years to produce figs without the need for their pollinators.
PALMER: Gosh. So, you say they've been around for millions of years. Are they kind of anchor species in different ecosystems?
SHANAHAN: Yes, they are. They're what biologists call keystone species. If you imagine a bridge, the keystone is the stone that locks all of the others in place. But if it goes, the whole bridge comes tumbling down. And because figs have this relationship with their wasps, they produce figs all year round, and this means that they feed a huge number of animals in rain forests around the world. Altogether, more than 1,200 species of birds and mammals eat figs around the world and so they are a massively important food resource, and those animals are the dispersers of many other tree species. So, if you take figs out of an ecosystem you take a lot more besides.
PALMER: What got you interested in figs in the first place?
SHANAHAN: Well, I learned about them a little bit when I was an undergraduate student of biology and when I was doing a masters project I was meant to be going to study birds in Indonesia, but the project fell apart and my supervisor felt a little bit guilty, and so he contacted some of his colleagues who were fig biologists like him and one guy in Borneo Rhett Harrison replied and said, yes, he could host a student for a couple of months. So, I went out and lived in the rain forest in Borneo and my project turned into a doctorate. So, I spent three years studying the figs there and elsewhere.
PALMER: That sounds pretty exotic, Borneo.
SHANAHAN: Yes, it was great. It was fantastic. I was living in a national park, which is one of the most biodiverse places on the planet really. It’s got thousands of species living there and has probably 75 or 80 different species of figs just in one place, so it's a real center of diversity. It has figs that are tiny shrubs, and some that are creepers, it has strangler trees, it has trees that produce the figs from the main trunk of the tree. It's even got some figs that produce their figs underground, on runneers underground. So, there's massive variety all in one place and it made it really good place to the study interactions between animals and plants there. And it was a fantastic field site. We had an aerial canopy that allowed us to walk through the canopy level of the rain forest on walkways and towers and observe life really where it's all happening up there in the top of the forest.
PALMER: So, those green or purple things that we see and periodically find in the shops and mostly find in cookies and biscuits and the like, that's not what most figs are like.
SHANAHAN: That's right. There's a whole variety. They come in all shapes and sizes, different colors. They can be as smaller that a pea or they can be bigger than a tennis ball. Some of them are hairy, some of them are smooth, some of them are purple, black, orange, gold. All these different colors. And all of this variety is reflected in a sense in the variety of animals that come to eat those figs. So, you'll find that bats like to eat figs that are green and smelly and birds like to eat figs that are bright red.
PALMER: You talk -- you give a great description actually about strangler figs. Can you describe what they are?
SHANAHAN: Well, most plants start out in life on the ground and grow upwards, but strangler figures do the opposite. They start out in life as a seed that is dropped from a bird or a bat or a monkey or some other animal, and which lands high up on a tree in a rainforest, and that seed then germinates and sends down some roots which descend all the way down the host tree wrapping around it, merging, splitting, merging again until there's a basketwork that's spread all around the host tree, and this is what a strangler fig is. You can have situations where the host tree dies and what you have left is a hollow column and you can go and step inside it and look up and see this architecture that has been created from the top down. And these trees are the ones that are really important for wildlife in the forest because they feed a huge variety of birds, bats and other creatures, and they produce up to a million figs more than once a year, so they're like pop-up restaurants in the rainforest.
PALMER: You talk about them as keystone species, but they've also become hugely important mythological species in many, many cultures. Why is that?
SHANAHAN: Well, yes. They're found in every major religion, they're found in traditional cultures all around Africa, Asia, Latin America, the Pacific, Australia and more, and part of the reason is their biology. So, some of these trees are really awesome things to look at, the strangler figs and the banyans, and no doubt they captured the imaginations of people a long, long time ago. Also, they're very important ecologically. So, it would make fine sense for any society that protected these trees because they would get the benefits of what the trees do in the environment by sustaining the wildlife and also by providing other goods and services that people can benefit from. Many are also sources of traditional medicines and of shelter, of shade and all of these things together have combined to allow these trees to be embedded in human cultures to the extent that's all around the world there are taboos against chopping these trees down. In Madagascar and India and Mexico, you'll often find that a forest has been cleared, but what's been left standing is a fig tree. Now, it's very different in the very modern time. Now, it's much more likely that you'll see fig trees being cleared, whether it's to widen roads or to increase agriculture. So, we are at a moment in time where perhaps those old lessons from the past should be remembered again.
PALMER: So, you think they still have a really vital importance for us?
SHANAHAN: Well, they do, because forests are falling all over the world, and especially in the tropics. And the more forests fall, the less we can use forest to protect ourselves from climate change. And in fact, there are people who are using fig trees in different countries now in order to boost rainforest regeneration. The idea is if you plant fig trees, you attract lots of other animals that disperse the seeds of different tree species and the rain forest recovers quickly. And this has happened in Thailand, in South Africa, in Costa Rica and in Rwanda. All of these projects are currently ongoing right now.
PALMER: That sounds really interesting. You talk in your book about how fig trees are able to colonize places, which seem incredibly inhospitable like lava fields after a volcano. Tell me a bit about that.
SHANAHAN: That's right. I've been on a volcano that was just bare lava, and there was a tall fig tree growing there. It's interesting that all of the other plants in that area were little weedy grasses, but there were several fig species growing in this bare lava. And if you go to any Asian city, you will find fig trees growing out of walls, you’ll find them growing off the top of buildings. They can germinate in pretty much bare ground. Their roots are very strong, and they can rip apart rock even. So, these trees are very good at colonizing land that really looks beyond repair, such as a mining site. And once the fig trees get in and start breaking up that substrate, they allow water and oxygen to get in, soil starts to form, and other plants can then follow onwards.
PALMER: Wow. You also talk about places where the fig wasps died out and so they aren't actually managing to fertilize the figs anymore.
SHANAHAN: Well, there have been times when fig wasp populations have just disappeared almost overnight in different parts of the world. So, where I was in Borneo, there was a really really intense drought in the late 1990’s and lots of the fig wasp species just went locally extinct. They couldn't handle the heat, and also the fig plants stopped producing the figs. So, the wasps had nowhere to go, and what happened was that the wasps eventually returned after several months, but for a long time there was no pollination happening, no seed production happening, and animals in the forest were probably going quite hungry. They tend to bounce back though because these tiny little insects can travel huge distances in just a couple hundred days in which they live. And in time, they can return to these areas where they've been taken out from.
PALMER: Yes, actually you describe what a short period of time the fig wasp has to do the important job it has to do. Explain to me how that works.
SHANAHAN: Well, when a fig wasp is born, the female emerges from within the flower where she's developed inside a fig, and she mates with the male and then pretty much that's it. She's off. She leaves the fig having picked up some pollen and now she own has about 24, 48 hours to reach another fig of the right species in the right stage of development that will let her enter so she can go in, lay her eggs, and also deliver the pollen that she's brought with her from the fig of her birth. And in that two days, that's not a very long time but she tends to fly up into the high levels above the forest and the wind will blow her a long, long way in a short time. We've got some evidence that figs can transmit pollen for 160 kilometers, which is about 10 times more than any other insect have been recorded doing that.
PALMER: And it's very dramatic when they actually get to the fig.
SHANAHAN: That's right. Each fig has a tiny little hole in it, which is the entry hole, and the pollinator wasp must force her away in this hole. So, she sticks her head in, and her head has been adapted over millions of years of evolution to be the right shape for forcing her way in. And as she squeezes her way in, the antennae will be wrenched from her head and the wings will be pulled from her back and she eventually finds herself in the hollow heart of the fig where she's got her egg laying and pollination to do, and she doesn't need those things anymore ... her wings ... because she's going to die inside that fig.
PALMER: So, every single fig sees the sacrifice of many fig wasps.
SHANAHAN: That's right. Well, the females that arrive and lay their eggs, they aren't sacrificing much because they're passing on their genes to their offspring. But there's also a whole other battleground inside the fig because there are plenty of other parasitic fig wasps that come along and lay their eggs in the offspring of our pollinator fig wasps, and there's a whole drama that goes on between these different species.
PALMER: So, at a very tiny level this is nature red in tooth and claw?
PALMER: As you describe it, these become the most fascinating species. But what was it that got you about them really.
SHANAHAN: Well, I always came from it from the wildlife angle. I was amazed that so many different things eat the figs. We're talking about elephants and rhinoceroses eating figs. There are hundreds and hundreds of bird species and monkeys and fruit bats, but also weirder things. There are fish and there are tortoises that have been recorded eating figs. Even lizards dispersing the seeds of figs. So, it really struck me that this whole Noah's Ark of animals was feeding off one group of plants. It was pretty amazing, but it was later on when I started hear about all of the cultural stories about figs that I really got more excited about this idea and that there might be a book in this. And since then I just can't stop myself finding more and more interesting things about these plants. They have so many superlatives about them that I felt it was definitely the time to write a book about these things.
PALMER: Superlatives such as?
SHANAHAN: Well, some of them are the biggest trees in the planet. There's one in India that can shelter 20,000 people beneath its crown because it's such a big tree.
PALMER: And yet as you say we are actually threatening these with our deforestation and also with climate change. How serious do you think this situation is?
SHANAHAN: Well, if you take it from the figs' perspective, this is just a blip in their huge huge huge timeline of existence. More pressing, I think, is our own vulnerability to the climate and our own vulnerability to other environmental issues. And the good news is that figs can help us address those challenges by helping us to reforest land that has been logged and helping us protect to the wildlife that sustains so many other species.
PALMER: Now, you say there are efforts underway to restore them to their natural habitats. Tell me a bit about those.
SHANAHAN: Well, in some places, people have been using fig trees amongst other plants to encourage other species to come in. So, with plants like figs, which grow fast, have strong roots and produce thick leaves and shade, the weeds can't grow, the figs grow very quickly and produce their figs in just a year or two, and this attracts lots of animals. This has been going on in Thailand where they have been reforesting parts of a national park that villagers had turned into agricultural fields. The forest is returning very quickly. Lots of wildlife is coming back. And in Rwanda and in Costa Rica, they're taking a different approach. They are lopping off huge branches several meters long from mature fig trees and just sticking them in the ground as instant trees, and again these trees are very quickly producing figs and soon after that, what will happen is other trees will populate the area because the animals that come to eat those figs will be bringing many other seeds.
PALMER: When it comes to restoring fig trees to their original habitats, what kind of technology are people using now for that?
SHANAHAN: Well, in Thailand, a biologist called Steve Elliott is exploring how to use drones to carry the seeds out into distant places and deposit them along with a little package of hydrating gel that will give them their best chance of starting out in life. These places are often quite inaccessible and it is difficult to carry trees that have been planted in a nursery up and down slopes and then bury them in the ground in faraway places. So, by using drones, this is how he hopes to accelerate the process.
PALMER: Mike, you talk about the secret history. What is the secret history?
SHANAHAN: Well, one of the secrets is the nature of the fig itself. For a long time, people thought it was a fruit, and for a long time people thought that fig trees didn't produce any flowers. And the secret is that actually, the fruit is not a fruit. If you look inside the fig, you'll find the flowers, and each of those flowers is capable of producing a tiny little fruit, which to our eyes looks more or less like a seed. In fact, it is a capsule that holds together all of this plant genus's power.
PALMER: Mike Shanahan is a freelance writer with a doctorate in rainforest ecology and the author of “Gods, Wasps and Stranglers: The Secret History and Redemptive Future of Fig Trees.” Mike, thanks very much.
SHANAHAN: Thanks for having me. It's been a pleasure.
- Gods, Wasps, and Stranglers: The Secret History and Redemptive Future of Fig Trees
- Mike Shanahan’s blog, “Under the Banyan”
- HowStuffWorks: “Are figs really full of baby wasps?”
- Planting trees with drones
[MUSIC https://www.youtube.com/watch?v=7wtd9Esbv0k LAGQ, “Fragile”]
PALMER: Living on Earth is produced by the World Media Foundation. Our crew includes Naomi Arenberg, Bobby Bascomb, Savannah Christiansen, Jenni Doering, Noble Ingram, Jaime Kaiser, Don Lyman, Alex Metzger, Helen Palmer, Adelaide Chen, and Jolanda Omari. Tom Tiger engineered our show, with help from John Jessoe and Jake Rego, and Thurston Briscoe edited the show. Alison Lirish Dean composed our themes. Steve Curwood is our executive producer. You can hear us anytime at LOE.org -- and like us, please, on our Facebook page -- PRI’s Living on Earth. And we tweet from @LivingOnEarth. I'm Helen Palmer. Thanks for listening.
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