Who's Your Mama? Conservation Genetics and At-Risk Species
USGS science supports management, conservation, and restoration of imperiled, at-risk, and endangered species. Endangered Species Day is commemorated in May, and we’re taking some time to find out just how one goes about studying at-risk species and what part cutting-edge technologies can play in helping us do the science that informs managers and policy makers. Catherine Puckett talks with USGS scientist Dr. Sue Haig about her conservation genetics work on imperiled species.
Catherine Puckett: Hello and welcome to the USGS CoreCast. I'm your host Catherine Puckett. Today, I'm talking with Dr. Sue Haig, an authority on using both traditional and cutting-edge techniques to assess the status and health of threatened and endangered species, particularly birds. So, Sue, first a little background, what is an imperiled
Sue Haig: Imperiled species are those species which can't maintain healthy populations without help from humans. So these are species and populations of animals and plants that are in decline and may be in danger of extinction, but more often than not, many species are not being protected because of a lack of knowledge about their status and the environmental factors that may threaten their future.
So, as the principal research agency for the U.S, Department of Interior, we at the USGS – the U.S. Geological Survey -- are conducting research to fill these gaps in our understanding of species so that these imperiled species can be better managed and conserved.
Catherine Puckett: When most of us everyday folks think about endangered and threatened species, we think about polar bears on an ice flow or maybe a wolf or something like that, but we don't really think much about how scientists assess the status and health of these populations. What are some of the challenges involved in studying imperiled species?
Sue Haig: Well, the problem is the smaller a population becomes the less of a chance that it will recover, and the more drastic scientific and conservation measures that may have to be taken. So it's always better to address declining species issues before the situation becomes really bad. And in terms of studying endangered species, I think it's important to understand that these species are not talking to us. They're not walking around wearing signs that say, "Check our lead levels." So we often don't know what it is that caused their decline. There can be a long period of time where scientists have to test various hypotheses regarding the decline of the species before we can design appropriate conservation measures.
Meanwhile, the species continues to decline, so we're always in a bit of a panic over getting the best data out as quickly as possible because the clock is ticking. To give you an example, it took a long time for scientists to figure out that disease-carrying mosquitoes were causing the decline of the native birds in Hawaii. And we didn't know immediately that the brown tree snake was causing the native forest birds on Guam to go extinct.
And it's taken over 20 years for scientists and others to realize and accept that lead from hunters' bullets and animal carcasses is causing the extinction of California condors. So, the bottom line is there's no single answer or approach to designing these investigations, but I'd say that the best overall approach is to acknowledge or say, ok, I know we have to think about many different factors, and we want to test multiple hypotheses so that we can keep an open mind and really discover what is the cause of the decline of the species.
The USGS has many scientists with really varied backgrounds. So, I can unabashedly say that we're the best scientific agency that's trained to address these issues. And our expertise has to range from understanding the policy implications of the Endangered Species Act to designing very thoughtful and careful field investigations to using molecular markers to diagnose population structure and decline. We are even involved in designing vaccines to mediate disease risks.
Catherine Puckett: OK. So, what are molecular markers?
Sue Haig: Molecular markers are genetic markers that we can design to identify individuals or populations or species or higher-level taxonomic groups. We use them in conservation work to diagnose problems, or to describe problems, so that we can design recovery strategies that are appropriate.
Catherine Puckett: Do you go out and get a feather from a bird and get the DNA or what?
Sue Haig: It's pretty incredible, actually. Things have changed so much since when I started in graduate school studying genetics. [Then] I had to carry around a tank of liquid nitrogen and a centrifuge and I had draw a lot of blood and spin it down and separate the cells and freeze it and all this. I was doing this in Mexico on a truck. It was complicated, but now we can use almost any piece of anything that's part of an animal to extract DNA from. We can use feathers, blood, bones, tissue, beaks, eyes, anything. It's just remarkable. So, we extract the DNA from the tissue and then we're able to use various techniques to identify specific points along the DNA sequence and compare them across populations or individuals or whatever the groupings are that we're concerned with. We can see what is different and what is the same, and then we can summarize that and give ourselves and managers an idea of the status of a population or a species or what not.
Catherine Puckett: So, you have an example on Micronesian kingfishers; I think they're one of the species that was affected by the brown tree snake?
Sue Haig: Micronesian kingfishers, of course, are birds that used to live in the forest in cavities or in termite mounds in Guam. They went down to about 28 individuals in the early 1980's, and they went extinct in the wild in 1987. They were brought to National Zoo; the challenge was to try and figure out who these birds were. Were they related to each other or not?
But even more than that we needed to understand what species they belonged to because there are Micronesian kingfishers described from three other islands, and so we needed to know -- we still need to know actually -- if those birds that have all been described as Micronesian kingfishers—and they look different -- are truly the same species or are they different? We need to know that because we are trying to reintroduce Micronesian kingfishers from Guam back into the wild.
They are in captivity now but we want to put them back -- not back on Guam because the snakes are still there -- but we're trying to introduce them to other islands. Their populations in captivity are so low that if we could actually crossbreed them with birds from Palau or Pohnpei, we think a population would grow better and faster but if they are different species then we're getting nowhere. So, we're using molecular markers right now. The biggest question now is are they different or are they the same?
Catherine Puckett: Sue, I know that you lead the conservation genetics laboratory. Can you give me some idea about what you do there?
Sue Haig: Our lab, I think is unique in that we are both a molecular lab and field ecology lab. That's because I don't believe that any one approach is always the best and the most comprehensive approach to recovering endangered species. In our lab, as I described, we use various molecular markers to address different questions but we also are out in the field where we're working on dispersal studies so that we can link that dispersal information with the genetic information that we're finding in the lab. The reason that it's important to link those two is that genetic diversity is maintained or gained in populations by having individuals come in with new genetic makeup from different populations.
So, if you can measure genetic diversity then you can observe which birds are going to what population. You can get a better idea of where and why some populations are more robust than others. You can also diagnose which populations are becoming more fragmented and more isolated from others in the population. We're in the depths of trying to design an introduction, or reintroduction really, of California condors into Oregon. So, we are using the dispersal information from the condors in California to learn how they move among populations. And we're using molecular markers to determine which birds might be the best to put into the Oregon population and so forth.
So that within the next couple of years we hope to have a robust population of condors in Oregon.
Catherine Puckett: What about tracking individual animals?
Sue Haig: For the salamander or butterfly, using molecular markers to track movement can be great. On the flip side, we have developed -- not we our lab, but scientists -- have developed these amazing satellite transmitters which you can put on an animal and you can track it [the animal] from your computer at home. The problem is those transmitters are pretty big right now so we can't use them on smaller animals. So what's happening is I have been working with Pete Marra at the Smithsonian Migratory Bird Center to develop an initiative called the Migratory Connectivity Project. What we've done is we’ve brought together the best experts in the world in tracking animals to try and push forward some of the bottlenecks -- or push through the bottlenecks -- that are occurring in being able to track animals.
Because without being able to track them, we can't design conservation strategies. So, we've got people on our board that are from the Max Planck Institute, for example; they are launching a satellite on the next space shuttle launch -- not the U.S. space shuttle -- the Russian space shuttle -- that will launch a satellite into space that will just track animals, which is sort of mind-boggling. People have developed unmanned drones to fly around and track animals. I mean, the technology is amazing but it's still not perfect for every task that we want to deal with. So, we're pushing really hard to get some of this technology better developed.
Catherine Puckett: How did you originally become interested in this field of science? And what is it that keeps you engaged day after day?
Sue Haig: The bottom line is, it's crazy, but it's this love of nature and it's this understanding of the amazing beauty of nature and how much we don't want that to disappear.
Catherine Puckett: Have you always been like that?
Sue Haig: Yes. Actually, as it turns out, I was not a kid that was wondering what I was going to do when I grow up. I knew from a very young age I was going to be a biologist. I was 5 years old, and I became obsessed with butterflies. I remember one time I walked away from my parent's house and I walked a mile to a store. I took 50 cents, which was a fortune at that time, and I bought this book, "The How and Why Wonder Book of Butterflies and Moths," which I still have.
My parents were going nuts looking for me. So, when I got home I got grounded but while I was grounded I made a butterfly net and kill jar and my little pins and whatnot and I made a butterfly collection. That's my first memory of really trying to think about science, but I just can't imagine living without it.
I've just always been that way. I try to be the best scientist that I can be but part of that means I need to work with a real diversity of people -- everyone from the park rangers I’m going to be dealing with in Kenya to policy makers to really make them understand what our science is telling them. Because if we do all these amazing scientific things but we can't really convey the importance of them and how they can be used, there’s really no point in doing it.
Catherine Puckett: Well, thank you for communicating with us today.
Sue Haig: Thank you, Catherine. Thanks for asking me.
Catherine Puckett: All right. I'm Catherine Puckett. CoreCast is a product of the U.S. Geological Survey, Department of the Interior.