MR. KOJO NNAMDIFrom WAMU 88.5 at American University in Washington welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. Why are some creatures like robins so common, while others like the Maned wolf so rare?

MR. KOJO NNAMDISurprisingly, human activity is not to blame in most cases. Rarity, as it turns out, is very common in nature. Of the estimated 15 million species on Earth, most are very few in number. Wildlife biologists are tracking these animals in hopes of understanding why they're scarce and what it means for conserving the thousands of other species that are endangered.

MR. KOJO NNAMDIThere's good news, too. Conservation efforts are paying off and some of the most successful ideas are happening in unexpected places. Joining us to discuss this is Eric Dinerstein. He is the lead scientist and vice president for Conservation Science at the World Wildlife Fund U.S. He's also the author of "The Kingdom of Rarities." Eric Dinerstein joins us in studio. Eric, good to see you, thank you for joining us.

MR. ERIC DINERSTEINMy pleasure to be here, Kojo.

NNAMDIIn case Eric Dinerstein's voice sounds familiar, it's because you may have heard him on the February 9 edition of "Animal House" here on WAMU 88.5. Eric, rarity, ironically, is actually very common in nature. Can you explain this apparently counterintuitive fact?

DINERSTEINRarity is very common and, you know, Kojo, it's a fact that most people and, in fact, even many scientists aren't even aware of. There's a great asymmetry of life on Earth. Perhaps something like 90 to 95 percent of all organisms are drawn from only 20 to 25 percent of species. That means that the other 75 percent, that's a boatload of rarities.

NNAMDICan you explain the difference? What is a rare species versus an endangered species?

DINERSTEINSure. So a rare species is we think of a species that has a very narrow range, like let's take the Javan rhinoceros that only lives in a very, very small peninsular near the volcano of Krakatau in the western tip of Java, so a tiny range. That's the first part.

DINERSTEINAnd then a species that has a very low abundance, so think about any top predator like a jaguar in the Amazon or the tiger in Asia. They always occur at very low densities. So that's another feature is small range, low density or sometimes both.

NNAMDIIf you have questions or comments about rare species, call us at 800-433-8850 or send email to kojo@wamu.org. Did you know that there are some 15 million species on Earth? The vast majority of which have not been named or catalogued. Give us a call at 800-433-8850. Send us a tweet at @kojoshow or go to our website kojoshow.org and join the conversation there.

NNAMDIEric, one would think that rare creatures, because there are fewer of them, are somehow less important to the animal kingdom and the natural world in general than more common species. Is that the case?

DINERSTEINNo, it's not and, in fact, rare species can have a dramatic impact on their environment. Let's take, for example, animals that people love, the elephants. We find that elephants and also rhinos are tremendous, what we call, landscape engineers or landscape architects, that even at low densities they can shape the world around them by what they eat, what vegetation they prune and even, in fact how they defecate.

NNAMDIOne of the biggest questions that you and other scientists are trying to answer is why some species are rare while others are common? Why is that question so difficult to answer?

DINERSTEINThat's actually the fundamental question of biology and a lot of people scratch their heads over it. Some of the basic explanations are that some species have -- most species have very specialized habitats that they need and in some cases those specialized habitats are very, very rare. In other cases, they're very common.

DINERSTEINSo, for example, take a species like the Black-tailed prairie dog that used to be one of the most abundant species here in North America. Grasslands were very common and are very common across the western part of the U.S. and so their habitat was abundant. But then you have species that have very specialized habitats like the Kirtland's Warbler in Michigan that only lives in very young Jack Pine stands on very sandy soils. That's it. If they can't find that habitat, you won't find them.

NNAMDIIt's surprising to learn that we humans are not the cause of most species being rare. Can you talk about that and other possible reasons that some animals exist in small numbers?

DINERSTEINA lot of animals have very, very localized distributions so typically if you go to any tropical country that's mountainous, you have -- on the tops of those mountains, you have species that are found there that are found nowhere else. They evolved in isolation from other species and that's where they've stayed and so that's very, very common to see across the tropics.

DINERSTEINThere are other places where species have been -- their numbers have been brought to much lower levels because of human activities, but those are also often very recent and those are the ones that we need to reverse if to avoid extinction.

NNAMDIAlthough human activity may not be the cause of most rare species, we are, of course, the reason many are in danger of becoming extinct. What are some of the ways we're threatening both rare and common creatures?

DINERSTEINPerhaps the biggest way that we're threatening rare and common creatures is the clearing of tropical rainforest. So here's another great asymmetry of nature. Perhaps more than 60 percent of all species on Earth are crowded into the 5 percent of the land area that are tropical rainforest. They're so rich in species and therefore they're so rich in rarities.

DINERSTEINBut there are also common species that are in rainforests and because sometimes the size of the area of a football field is cleared every single minute in the tropics, we're losing these rare species.

NNAMDI800-433-8850 is the number to call. Our guest is Eric Dinerstein. He is the lead scientist and vice president for Conservation Science at the World Wildlife Fund U.S. He's also the author of the book "The Kingdom of Rarities." Our number is 800-433-8850, if you have questions or comments about rare species. What do you think we should be doing to protect endangered species? 800-433-8850 or send email to kojo@wamu.org

NNAMDIMany of us have heard that there are some 20,000 species on the endangered list. Are the numbers that daunting?

DINERSTEINIt's certainly that, the high numbers are of great concern to us. But I think that one of the real success stories that we have, whether it's the Bald Eagle or the Peregrine Falcon, species here in the United States where the government and conservation groups and even local citizens have all worked together to try to bring these species back, how successful we've been.

DINERSTEINI'm really convinced, Kojo, that it's really a question of political will and a desire to do so. There's really no species that's on the endangered species list we probably couldn't recover if we put our minds to it.

NNAMDIGiven how interdependent species are, what does losing a species to extinction mean?

DINERSTEINIt really depends upon which species you're talking about. But if there are species that are top predators like tigers, when you take the top predator out of a system, that system often goes haywire. Now we can see this right here in the Washington, D.C. area. When you just drive around, you see the vast number of White-tailed deer on the roads and sometimes as roadkill and imagine if we still had wolves and mountain lions along Rock Creek Park or along the Potomac.

DINERSTEINThe White-tailed deer that are going through here that eat up a lot of native plants, a lot of endangered plants, they wouldn't be walking around as if they were on a garden tour. They'd be much more scarce. So when you remove the top predators, that large herbivore, those populations often explode and that has dire consequences for the ecosystem.

NNAMDIHence the controversy over culling deer populations in this area, the controversy over using sharpshooters for deer, that wouldn't exist were it not for the fact that the top-line predators were becoming, in some cases, extinct.

DINERSTEINExactly. So wherever you go, one colleague called it the landscape of fear. That's what these species like deer and like zebras experience in Africa with lions around or deer and wild boar in the country that I work in quite a bit in Nepal. When there are tigers around, is they have a sixth sense of where these predators are and they make themselves scarce.

NNAMDIWe've been hearing dire predictions about the rate at which species are becoming extinct since the 1980s and, in fact today, there are more tigers in private hands in the state of Texas than there are in the wild. What kind of a conservation crisis are we in at this moment?

DINERSTEINA few years ago, Kojo, some colleagues and I who -- we all study tigers, were sitting around and realized that what we were doing wasn't working, that we had to come up with a more effective way of conserving tigers. So there are probably -- we discovered there are probably only 3,200 tigers in the wild as you say and what we did was we marshaled political will at the highest level.

DINERSTEINWe staged, the first-time ever, a global tiger summit in St. Petersburg, Russia hosted by Vladimir Putin and then president of the World Bank, Robert Zoellick. And since then, we've done remarkable things for recovering tigers. Their numbers have increased dramatically.

DINERSTEINThe heads of state of all the tiger-range states have agreed to a program that brings tigers back and we've raised far greater sums of money to be able to do this than ever before. So it's one more example of when you put together the political will and the concerns of ordinary citizens that we can do great things to restore these charismatic species.

NNAMDIWith so many species at risk, how do you and other scientists decide which species to focus on for both purposes of research and purposes of conservation?

DINERSTEINThat's a good question. I suppose everybody has their personal favorite. For me, when I was five years old and I was looking up in a diorama at the Museum of Natural History in New York at the Greater one-horned Rhinoceros, I thought it would be so cool to someday go and study this animal. And then 25 years later, there I was on the back of an elephant in pursuit of this species. So I guess, for me, it's been iconic.

DINERSTEINIn my book, I call it the quest-species, species that you have to see before you die, that somehow touch you and their very presence shadows you in your existence until you see them or, in my case, to study them.

NNAMDIMore about you and the rhinoceros later, but first, here is Robert in Gaithersburg, Md. Robert, you're on the air. Go ahead, please.

ROBERTYes, thank you very much.

NNAMDIAllow me to have Eric put on his headphones so he can hear you, Robert.

ROBERTSure.

NNAMDINow, Robert, you can go right ahead.

ROBERTSure, no problem. Listen, I'm obviously partial to the local areas here. I'm not a traveler so I don't go all over the world looking for, you know, extinct or rare species, but, you know, just here in the Washington area -- I live in Gaithersburg. The development is not monitored and not controlled the way it should be. It is a system that allows the highest bidder to drive around, look for land and slap down an offer to these farmers, anybody willing to sell land for the highest price.

ROBERTThere is no control for retaining wildlife buffers. In our grandchildren's lifetime we're going to see the extinction of animals that we have take for granted as kids growing up. It's sad. There's no control on development and the developers are the greediest, lowest life people on the planet.

NNAMDIWell, Robert, it seems that our guest Eric Dinerstein says there is something we can do about that, right?

DINERSTEINAnd I'd also like to point out that that's one side of the equation, and I certainly take the caller's point on that. But then the other is just -- I live in Cabin John so in the D.C. area, and the last two days I was riding my bike along the towpath out to Great Falls Park. And it's a place I go all the time. And in fact, that park conserves a whole number of rare species of birds and plants and mammals. And I'm just sometimes stunned by the brilliance of those who fought so hard to make that park happen, that we just take for granted every day that it is a collection of rarities that they have conserved in it. And we're so fortunate to have that right in our midst.

DINERSTEINYou know, Kojo, I've traveled around the world and what some people don't realize is that the Potomac River is probably the wildest river to flow through a capital city of any country in the world.

NNAMDIReally?

DINERSTEINIt is. How many countries have a river that goes through their city conserved with a national park on either bank? It's truly remarkable.

NNAMDIThank you very much for your call, Robert. Here is Donald in Falls Church, Va. Donald, you're on the air. Go ahead, please.

DONALDYes, thank you. I'm aware of the number of attempts that mail orders that come in which ask me to donate money for the rainforests. I can't think of the names exactly right now but they deal with Rainforest Alliance and other organizations that -- even Arbor Association wants to dedicate money toward preserving either acres of land in the rainforests or in some other fashion forming alliances. Can your guest comment on the success of those alliances?

DINERSTEINSure. I think that every conservation group that's making an effort to save rainforests should be applauded. It's the greatest conservation struggle of our time. It's where most rare species and most endangered species are concentrated. And certainly my group World Wildlife Fund has done a great deal to try and do that. For -- one example would be in the country of Brazil with a program like ARPA, setting aside areas the size of the country of France in the next few years to protect endangered wildlife.

DINERSTEINAnd so I think that all of these groups are very valuable. The real question for all of us is how do we do this at scale? So not just a few acres here and there, but how do we set aside these massive areas, like 5,000 or 10,000 square kilometers, which I describe in my book in a chapter in the Peruvian Amazon they're needed to conserve healthy populations of jaguars. So that's the real challenge for us is how to make these large park viable.

NNAMDIDonald, thank you very much for your call. I'm glad you brought up the Peruvian Amazon because it's my understanding that technology is helping in a big way things like lasers that can pinpoint monkey habitats in the tree canopy of the Peruvian Amazon. Can you talk about how technology is changing the way you and your colleagues do your work?

DINERSTEINSure, Kojo. You know, I sometimes describe this to friends of mine as that wildlife science and wildlife conservation is entering its NASA moment, in that we're applying these amazing new technologies for learning a great deal more about species that until now were so cryptic. So let's take the one you just described. It's called the Bald-faced Saki monkey. Nobody knows anything about it, like where they are and yet we know they're around.

DINERSTEINAnd my colleagues use this ingenious device, an airborne laser that flies over the rainforests. And what might look like everything uniform to you or me and an airplane flying over, it looks very different to a laser that creates a three-dimensional image of the forests. And what they found is that these Bald-faced Saki monkeys are like giant squirrels. They -- you only find them where you have the densest, highest canopy with the widest branches. And those are their runways.

DINERSTEINNow if you or I were walking under the rainforest we never would have noticed that. But it was something that this laser scanner could see. And there's many other examples of new technologies we can use to really advance our understanding of how rainforests work and the animals who live in them.

NNAMDIYou're also using technology to bring wildlife tracking into the digital age. Can you talk about that and what it means in a field like yours?

DINERSTEINSure. You know, basically the easiest way to think about it is we're starting to enter an age now, and using field experiments where we're putting cell phones on animals to communicate with us. Not only to tell us where they're going, like in the case of tigers that are using corridors that we've designed, but to protect them as well. So I'm involved in a new project that looks at how do you use these new technologies to get two steps ahead of the poachers by applying cell-tracking devices and unmanned airborne vehicles that can provide guards with up-to-the-minute information about where the animals are, where the poachers might be and a way to head them off.

NNAMDISo is wildlife biology today a job that's done sitting in front of a computer screen?

DINERSTEINNot entirely. In fact, there's still, thank god, a very much need for people like me who like to walk around and pick up animal droppings and be out in the field. But I think that the wildlife biology and wildlife conservation in the future, as we practice at World Wildlife Fund is going to be a marriage between the traditional get-out-there boots on the ground and then also using these new technologies to be much smarter about how we do conservation. Everything from how we design reserves and where we locate them to how we protect the wildlife in them.

NNAMDIHere now is Pam in Falls Church, Va. Pam, you're on the air. Go ahead, please.

PAMThank you so much, Kojo. I just have a comment about the wildlife in Falls Church. I've lived here 18 years and we've seen every kind of wildlife that you would not expect. We have a quarter acre lot surrounded by other homes with quarter acre lots. And I've had a bobcat come into my backyard right up to my backdoor. I'm had foxes, coyotes, rare birds. And when I called animal control and said, ma'am there's a bobcat at my backdoor she said, you know, they've learned to live with us. She said, they're from here. This is where they live and they've come back.

PAMSo I just wanted to comment and see what you thought about that. And I'll take your answer off the air.

NNAMDIWhat do you think about that, Eric Dinerstein.

DINERSTEINI've live in -- I spent eight years living in the country of Nepal where people live next door to cats a big larger than bobcats, namely tigers. In fact, the largest tigers on the planet are not in the Russian Far East with the Siberian Tigers. They're in the country of Nepal where I once captured a male tiger that was 560 pounds, one of the largest ever recorded.

DINERSTEINSo you might think that people would be a little bit wary about living so close to something a bit bigger than a bobcat, but in fact a lot of the programs that we have developed at World Wildlife Fund and a lot of the initiatives that we sponsored are ways to encourage people to live closer to wildcats and not be so afraid, and for the cats and people to live in harmony.

DINERSTEINAnd that's really our big challenge really in wildlife conservation is how do we trigger those incentives the right way so that people will want to continue to live next to wildlife. And those wildlife species, whether they're bobcats or tigers, are worth more alive than dead. That's our big challenge.

NNAMDIOur guest is Eric Dinerstein. He's the lead scientist and vice president for conservation science at the World Wildlife Fund U.S. He's also the author of the book "The Kingdom of Rarities." If you'd like to join the conversation calls us at 800-433-8850. What do you think we should be doing to protect endangered species? You can also send email to kojo@wamu.org. If you have called, stay on the line. We will get to your call. First we've got to take this short break. I'm Kojo Nnamdi.

NNAMDIWelcome back. Our guest is Eric Dinerstein. He is the lead scientist and vice-president for conservation science at the World Wildlife Fund U.S. He's also author of the book The Kingdom of Rarities." We're inviting your calls at 800-433-8850. Have you ever seen a bald eagle or other endangered species in the wild? What do you think we should be doing to protect those endangered species, 800-433--8850?

NNAMDII'm going back to the phones in a second but, Eric, first technology is obviously helping but there are still a vast number of unnamed species all around us. It seems there's an enormous amount of research that still needs to be done in so many areas. What about the next generation of wildlife biologists?

DINERSTEINThe next generation of wildlife biologists are going to be, I think, people who bring together a range of skills that include certainly the technology part of it that I talked about and a love of the field. But, you know, one of the wisest wildlife biologists I've ever met said that conservation is 10 percent science and 90 percent negotiation. And that's a whole other part of our work at World Wildlife Fund, other conservation groups is that how do we figure out ways for people to want to live next to nature and for nature to have greater value in their lives?

DINERSTEINAnd so a lot of our work really focuses on those kind of incentives to help protect elephants, tigers, rhinos, gorillas in the places that they live.

NNAMDI800-433-8850. We go now to Brian in Springfield, Va. Brian, you're on the air. Go ahead, please. Hi Brian, are you there? Brian? Brian seems to have stepped away from the phone for a second. We'll put -- oh, I think Brian just came back. Brian, let's try you again. Brian, are you there? No, that is not Brian who just came back. Let's go to Wendy in Washington, D.C. Wendy, you're on the air. Go ahead, please.

WENDYHi, yeah. I just have a question. I volunteer at the zoo so I know there are lots and lots of species that are not well known at all and they're really important sort of integral parts of the chain of life. So I wondered if you could talk about the balance between attracting interest in conservation through, you know, the charismatic species that everybody knows about and then the species that maybe aren't known but are just as important.

NNAMDIWendy, you'd be interested to hear this email we got from Jasper in Alexandria. "Your guest talked about some of the more popular endangered species, tigers, rhinos, bald eagles. But what about the thousands that aren't as photogenic or popular? Does it affect the ecosystem that we tend to focus on a few superstars?" Eric.

DINERSTEINThose are great questions. And there's really a simple answer to that is that we pick these large charismatic iconic species that the public identifies with partly to help spread the conservation message. But there's actually a very strong scientific basis for choosing these species. Let's pick tigers. So typically a tiger ranges over an area that -- a small home range for a tiger would be about ten square miles. That's a very small one. But you go to the Russian Far East where the Amur tigers or Siberian tigers live. And that could be as much as 300 or 400 miles.

DINERSTEINSo in order to protect a viable or a healthy population, whether they're tigers or other species that live at these low densities, you need very large areas. Now all those other species that are, let's call them a little bit less charismatic, not uncharismatic, that people don't know about. They have very small home ranges, which means that you could conserve large populations of them in relatively small areas. So by using these other more well-known species as what we call umbrellas, you have this affect where by setting aside these larger areas you conserve all of those many unnamed species as well. Most unnamed species on the planet are either invertebrates or plants, and it's going to be awhile before we name all of those, but we do know that most of those are in the rainforest.

DINERSTEINAnd so if we use these charismatic species to protect rainforests, we'll protect those lesser known species as well that do deserve the attention.

NNAMDICharismatic megaphone is the term, we've talked about this on this broadcast in the past. Wendy, thank you very much for your call. We'd like to hear more about the actual tracking of these rare animals. You mentioned the rhino. You tell the story of catching a Greater One-Horned Rhino in Nepal. How and why did you track this animal aside from it being a childhood fantasy of yours?

DINERSTEINWell, they're also one of the rarest mammals on Earth, so at that time there were probably no more than 350 in this park that I was in, in Chitwan National Park in Nepal, and maybe no more than 2,000 in the wild. So it's an ancient species. They were once superabundant. Maybe 500,000 before the Gangetic Plain was settled by agriculture, but they'd been restricted to a few reserves.

DINERSTEINSo in order to better understand their biology, we were trying to bring new technologies to bear, in that time, radio tracking, and so in order to do that though, we had to capture the animals and attach these radio collars. And we did this also because we wanted to translocate, to move these rhinos to other reserves to repopulate them where they had been poached out, but where these reserves were now safe and could accommodate new populations. But the first order of business was learning how to catch one.

NNAMDIWell, can you tell us about the experience of catching an animal that's two meters tall?

DINERSTEINThat's right. So we use a drug that's actually a derivative of morphine to immobilize it that's a thousand times more concentrated. It only takes a tiny drop to immobilize an animal as big as a Greater One-Horned Rhinoceros, 4,000 pounds. And so the veterinarian with us hit it with a syringe dart from the back of a trained domestic elephant that got close enough.

NNAMDII was about to say, how high up were you when you did this. What kind of ladder did you have?

DINERSTEINYes.

NNAMDIOh, a real one, an elephant, yes.

DINERSTEINThat's right. So we used elephants that are very well trained and helped us get close to the rhino, and then darted it. Now, in the textbook, it says what you should do is once the dart has hit, to wait 10 minutes before you get down, and then you start attaching the radio collar or doing -- taking measurements of the animal. And so we got down, and the veterinarian said, let me just double check and make sure this animal's asleep, and then he poked it in the rear end with a stick.

NNAMDIAnd did the animal jump up?

DINERSTEINIt jumped to its feet and ran off.

NNAMDIYou're kidding.

DINERSTEINThat was a bit frightening. You know, there's -- I'm over six feet tall, and it was as tall as I was. More frightening was the idea that somehow modern pharmaceuticals didn't work against prehistoric animals. But it turned out that was the only time that ever happened, but because it was the first time -- since then, we've captured dozens and dozens of rhinoceros from moving to other reserves, for research purposes. We've never lost an individual. The drug is extremely safe. We've never had a person trampled, but the first time was quite exciting.

NNAMDIYou had the misfortune to run into super rhino the first time around.

DINERSTEINRight.

NNAMDIBack to the telephones. Here is Kevin in Haymarket, Va. Kevin, you're on the air. Go ahead, please.

KEVINHi, Kojo. Thank you for having me.

NNAMDIYou're welcome.

KEVINI was just going to ask you, yes, this weekend was the beginning of the great backyard bird count, and there's a lot of technology available to help track birds. I was just wondering what else could be done to help smartphone users and tablet users to help collect data on species and help scientists track species from like the comfort of their home, and from their smartphone device.

NNAMDIEric?

DINERSTEINSure. Smartphones are going to be an incredibly important tool in the future as more and more, it sounds like you, Kevin, citizen scientists get involved. I think that you know, there's only so much the individual scientists can do, and that more and more of population who becomes involved, and it sounds like you're an avid birder, I am too. That information is vital, particularly as climate change happens, we want to know how the movements of birds are changing with that, and people like you who pay close attention are vital to the whole scientific effort, so keep it up.

NNAMDIWe don't actually have to go to the mountains of New Guinea or the jungles of India to see rare species as people like Kevin can tell us. Where in our area can we see them?

DINERSTEINI'll give you two since I'm a local resident. One of my favorites is on Plummers Island. It's an island, if you go over to it, it's in the Potomac. It's near Cabin John, and there's a sign that says, Plummers Island, the best studied island in North America, because it was once a property of the Natural History Museum at the Smithsonian, and all the scientists there did studies on the island. So every single species there is identified and catalogued. It's truly amazing.

DINERSTEINBut on there are some incredibly cool species. You know, most people don't know about orchids in our area. There are 26,000 species of orchids in the world. In fact, it's the most numerous plant family there is. Think about this, Kojo. One out of every 16 or so flowering plants is an orchid. Here in the D.C. area, we have 46 species, all of them though are terrestrial. They're not like the ones that hang from trees, the epiphytic ones, that's tropical. But we have some amazing orchids here.

DINERSTEINSome of them are quite rare. One of them is called the Adam and Eve Orchid, so called because next year's growth comes out of last year's, kind of like how supposedly Eve came from Adam's rib. So it's called the Adam and Eve Orchid, and you can find it on Plummers Island if you look carefully. It's -- in its winter leaves, it's like one or two green leaves that are -- with silver racing stripes on the top side, and underneath bright purple. So there's marvels and rarities to find all around us.

NNAMDISo there's Plummers Island. What's the other location?

DINERSTEINThe other one is another great secret you do need to call ahead and get permission to visit there. It's outside the beltway near Upper Marlboro, it's called Belt Woods, and it is, believe it or not, it's the largest tract of old growth forest on the eastern seaboard. There are giant oaks there that are some of the oldest in the United States, and in the east, and it's a place where you could see, if you knew what you were looking for, some very -- a very rare orchid called the Coral Root Orchid, and very rare ferns, and it's the only place I've seen in the Washington D.C. area with red-headed woodpeckers nesting in that area.

DINERSTEINSo it's a truly special place. It's what the forests used to look like before there was wide-scaling felling of the trees.

NNAMDIKevin, thank you very much for your call. Climate change is obviously a big piece of this discussion. How is it affecting some of the species you've looked at?

DINERSTEINClimate change is a very serious problem for a lot of wildlife. I think the -- sort of the poster species for this is the polar bear, where we see the melting of the sheet ice that they use for foraging to feed on seals and other marine wildlife. That's disappearing at an alarming rate, and so I think that's a really clear one. Another would be sea turtles. Now, sea turtles nest on beaches, and as sea levels rise, many biologists feel that they're in great danger because the areas that are behind those beaches are being so developed that as sea levels rise, there won't be more sand deposited so that the sea turtles can nest.

DINERSTEINThey'll be right up against garages and villas and apartment buildings. And so I think any species that is affected in the marine world is one that we are greatly concerned about, particularly coral reefs. So that we know that with the potential changes from a changing climate of warming seas, could be the end for corals in a lot of places, and coral reefs are basically the tropical rain forests of the seas. So it's of great concern.

NNAMDIHere, back to Brian in Springfield, Va. Brian, you're on the air. Go ahead, please.

BRIANKojo, Eric, thank you very much. A great program. I appreciate you having me.

NNAMDIYou're welcome.

BRIANI have a question, actually two, for Eric. Eric, in your experience -- I'm both a developer and a hunter, and I'd like you to share your thoughts on the contributions that organizations like Ducks Unlimited makes to conservation, and also to ask you about a program I heard about where in the very rare species, they allowed -- they tried, I thought, to allow hunting rare species with a very high premium on the license, and that encouraged ecotourism and local economies.

NNAMDIEric Dinerstein?

DINERSTEINSure, great questions. First, on Ducks Unlimited, they do a wonderful job. We can honestly say that the restoration of a lot of water fowl populations and a lot of other endangered wading birds has been really addressed by the contributions of Ducks Unlimited to really restore habitat across the Midwest and into Canada. So kudos to them. On hunting of very rare species, or highly valued species, let's put it that way, for helping to provide an income for poor communities, this is something that's a little bit controversial.

DINERSTEINIn countries like Namibia where World Wildlife Fund works, we have a very, very successful program where local communities that own the wildlife will actually give permits to big game hunters who will come and only take a very, very small number of animals at a premium to do this, and that money will be plowed back into local communities for development and for conserving the much larger populations of say elephants or impala or kudu or other species that are often the ones most favored by the hunters.

DINERSTEINI will say though that a really interesting trend that's occurring in Namibia now is that programs that were set up years ago, that were part of -- that had this trophy hunting approach have now been superseded by, in many cases, ecotourism. I think of Namibia as, if you can imagine it, the wildlife of East Africa meets the scenery of southern Utah. It's just a spectacular landscape, and more and more people are coming there to experience that wonderful wildlife, but in a setting that's unique to the world. So I think that both can contribute, but it's really marvelous to see how much ecotourism is taking off in some of these places.

NNAMDIEric Dinerstein. He is the lead scientist and vice president for conservation science at the World Wildlife Fund U.S. He's also the author of the book "The Kingdom of Rarities." Eric Dinerstein, thank you so much for joining us.

DINERSTEINYou're most welcome. Thank you, Kojo.

NNAMDIAnd thank you all for listening. I'm Kojo Nnamdi.