University Place

cc >> Okay, let's talk a little bit more those corridors I was alluding to in the first talk. But first, I don't know if you knew, but back in 1908 the state of Arizona was on the verge of mining the Grand Canyon. So Teddy Roosevelt went to the Grand Canyon. He stood on the edge, he looked out over the scene, and he said leave it as it is. And fortunately, those were the days when congress and the President talked to each other and in short order we had the Grand Canyon National Park. Unfortunately, it's no longer an option to leave most of the country as it once was. Only 5% of the lower 48 states is in anything close to an ecological pristine state, and that's because 95% of our country has been logged or it has been tilled or it has been drained. It has been grazed. As we said before, it's been paved over or otherwise developed. We've straightened our rivers and we have dammed them and you can spell that anyway you want and several of them no longer reach the sea. Our air has been polluted. Our aquifers have been pumped nearly dry. Our climate has been changed for centuries to come. And we have purposely introduced thousands of species of non-native plants, plants that evolve some place else, 3,300 of which are now aggressively displacing native plant communities. We have carved up the natural world into tiny remnants of its former state, and each one of those remnants is too small and too isolated to sustain the species that run our ecosystems. And remember, those are the ecosystems that support us, and so we really have entered the sixth great extinction event in the history of this planet, but this is the first one to be caused by living beings. So we reached this current dismal state of environmental degradation for one primary reason. We have not abandoned the adversarial relationship that we had with nature when we were hunter/gatherer societies. And we have to remember, that relationship enabled those societies to survive. It was nature that used to eat us. It was nature that froze us. It was nature that flooded us and that starved us and that destroyed our crops. And the more we beat it back or tamed it or even eliminated it, the better off we were. And this worked for us for many thousands of years. So not only was it ethical to eliminate nature from our landscapes, it was necessary. We had a them versus us approach to nature. Humans here, nature some place else. But it didn't recognize our dependence on nature. Our dependence on the natural capital that nature produces. And the only reason that that was okay, that we were able to push back nature every place we went without causing widespread ecosystem collapse, is because there were so few of us. The Earth was huge, and most of it was untouched so it was a highly productive place. There were very few humans harvesting its vast resources. So it worked. It worked. But of course that's not the case today. We now have 7.2 billion people. That figure is rising quickly. It's about 1,400 times the number of people that were beating back nature in the old days when were were hunter/gatherers. And, of course, we have technology, so we are far better at beating back nature than we used to be. We literally can move mountains to take what we want from the Earth, and every day we take more. Of course, the problem with that is the Earth is not growing. It doesn't have more to give every day. So my goal here is not to convince you that humans are inherently evil beings that just like to kill everything around them. It's actually the opposite. We are products of our past. I want to convince you that we're products of our past. And that past really had very few limits associated with this. So the fact that we're encountering those limits now is something that is new to us. We have never encountered them in the past, and most people don't even believe they exist. Now, with that, I think we need to understand that if we're going to get past this approach to nature and solve the problems that we have. And I think we can understand it. But before we do that, let's talk about box turtles. Several people have asked about box turtles from my little example this morning. Do you have box turtles here? >> One. >> One.

LAUGHTER

I saw one too. This is an eastern box turtle. It was once very common in the east. Most people encounter box turtles in an old field situation, walking around in a meadow or prairie. So that's where they think they live. But, actually, box turtles spend most of their time in the woods, in little wood lots. And most of the time they're in the woods they spend buried beneath vegetation. But in the springtime they go a-courting. And if they are successful, the female becomes inseminated. That is when she leaves the wood lot. She will leave a shady area, find an area in the sun, dig a hole, lay her eggs, and then of course it is the sun that incubates those eggs. So when the eggs hatch, they're now outside of the wood lot. We know very little about baby box turtles because when they hatch they spend a long time underground. Sometime as much as a year underground, and you typically don't encounter them unless you dig them up by accident, and that's what happened here. We were planting a silver bell at home, and luckily the shovel didn't hit this little guy. But the next time you encounter them, they typically are back in the woods. Box turtles have a life history very similar to our own. They easily live 80 years. It takes decades to reach sexual maturity. So think of them as like Uncle Joe. They have the same life history.

LAUGHTER

Okay, this is the University of Delaware Agriculture Experiment Station, and this is what we call ecology woods or the wood lot. It is 35 acres. And you can tell it's isolated by agricultural and other things. Back in 1968, a man by the name of Paul Katz decided he wanted to study box turtles in a long-term experiment that lived in the wood lot. So he caught every one that he could find and marked them with little individual markers. And he found 91. 91 box turtles in 1968. If we look down from the sky, this is what the wood lot looks like. It has been isolated that we know of for at least 120 years but probably longer than that. It used to be isolated entirely by agriculture. Now we've got athletic fields on this side, ag fields over here, and then a four lane highway to the south. If we step back even farther, we've got the wood lot here. This is Web Farm Woods over here, and here's Iron Hill Park over here. And there are box turtles in each one of those habitats, but they no longer can move back and forth. They can't exchange with each other. This is Route 72. No way a box turtle can get across that. Can't get across Route 4 here. So that's what I mean when I'm talking about isolated habitat fragments. And the problem is when those female box turtles leave the wood lot in order to lay their eggs, this is what they're facing. Chances are they're going to get mowed or they're going to get plowed, but here's the real danger. I do have a picture of a squashed box turtle, but I've decided not to show you. A lot of people think I staged that and then squashed it so I could take the picture. No. And that is why in 1968 there were 91 box turtles, in 2002 there were 22 box turtles, and 2010 was the last time anybody's looked, there were just 12 box turtles in the wood lot. So this is a population that is realizing its extinction. And I'm sure it started to decline as soon as leaving the wood lot became perilous. As soon as we started to build our local populations. So it's not gone yet. People would say we still have box turtles, we don't have anything to worry about, but look at the population decline. That population will go extinct in that little wood lot, and that's what's happening to populations of lots of things in all of our isolated habitats. It's not just box turtles that are in trouble. All of our amphibians are suffering the same fate. Our reptiles are suffering the same fate. And it's a big surprise to a lot of people that many of our insects are suffering the same fate. This is a large species of carabid beetle. It's flightless. Many carabid do fly around, but this one cannot. And we did a study 25 years ago, I guess it's 30 years ago at this point, there was a healthy population of these carabids in the wood lot. We reexamined them. It's probably been 10 years now. Completely gone. They're gone from the wood lot. They still exist in a larger patch of woods down the road. So you would think 35 acres is big enough to maintain a population of insects. Uh-uh, it's not. It's not. And that's the problem. Our biodiversity cannot be sustained, by sustained, I mean forever because that's what we need, not just the next five years, by our parks and our preserves because they are too small. When you take a large habitat and you shrink it down to a small habitat, there's the small habitat, you're taking large populations and shrinking them down to small or tiny populations, and that's the problem because tiny populations are highly vulnerable to local extinction. Why? Because all populations fluctuate. Good times they go up, bad times they go down. If you are a large population, like this top line here, even in your down cycle, there's enough individuals that you can rebuild quickly when times get better. But if you're a tiny population, often in your down cycle you hit zero. You blink out of your little habitat fragment, and then you're gone. If you're the box turtle, you're not coming back. You can't get across those roads to recolonize. So we call this local extinction. And that's what's happening to habitat fragments all over the place. It's not just animals. Plants are doing the same thing. So conserving habitat fragments does not conserve entire ecosystems. You've probably heard of the famous quilt analogy. David Quammen I think was the guy who came up with that. But if you've got a quilt and you disassemble it so you have all the little patches, you don't have a quilt anymore even though you've got all the pieces. And that's really what we've done to our landscapes. So what has fragmentation done to our biodiversity? I gave you this stat this morning. It is whittling away at it at a constant rate. Our grassland birds are in trouble. Why? We've gotten rid of, what, 99% of our grasslands. Our forest birds are in trouble. Our scrub birds are in trouble. And those are just the things that we're measuring. So we need to think about these species as the natural capital that supports us. We know that losing capital is never a good thing. But losing natural capital is certainly not a good thing either. So biodiversity is an essential nonrenewable natural resource, yet we are fragmenting it to at least local extinction. So fragmentation is the problem, then building biological corridors could be a very important solution. And this is the standard model for biological corridors where you're connecting these isolated habitat fragments with more habitat. If we connect those isolated habitat fragments, they are no longer isolated. And if they're no longer isolated, the populations within them are no longer tiny. And if they're no longer tiny when they fluctuation naturally, they'll no longer disappear. So building this network of corridors throughout the Earth, but let's just focus on the US, is a vital part of the solution to our loss of species. There are convenient ways to do this, and by convenient ways I mean, we can do it with very little pushback because we're talking about building corridors on land that is not good for human use otherwise. So mountain ridges, repairing corridors, power lines offer an opportunity, roads might. Rangeland offers a tremendous opportunity. Let's talk briefly about each one of those. Now you have to live in the right part of the country, and that's part of the problem. But this is looking down on the Appalachian Mountains in Pennsylvania. These, of course, are the valleys, and we have taken all the land in the valleys. But the ridge tops are too steep to conveniently build on. And they make wonderful biological corridors with tremendous amount of connectivity along miles. Wonderful places for migrating birds and other things to move along. So those are, ridge tops can be really important, crucial, convenient biological corridors that you're not going to get a lot of pushback on. Riparian corridors. Now we do get pushback on these, but these are also extremely important areas. A riparian corridor, of course, is just the habitat along a stream or a river. It's an extremely important habitat because not only is it providing connectivity, it's filtering out all the nasties that particularly we put in from our cities and suburbs and also too much fertilizer from our farmland. So it filters out. This is a stream going down to the Susquehanna River over here, and if your corridor is wide enough, it will remove many of those pollutants before they get into your major bodies of water. Really important ecosystem services. If we were to create functional riparian corridors every place we had a stream or a river, we'd be done because we have streams and rivers pretty much everywhere. This is a map of the networks of streams and rivers, the major ones in the US, and you can see they go just about everywhere. The problem is that's not how we treat our streams and rivers. This is the Christiana Creek in Wilmington, Delaware. And, of course, rivers like this were a great place to build cities because it was important for commerce. We'd sail up there and we could deliver our goods. They're good places to live as long as it doesn't flood, but they do flood. They're never a good place to put a landfill, but we do that as well. So right now and along so many of our major river and stream corridors, those corridors are gone and we would need to put them back in thoughtful ways. So that would be a challenge. This is what a lot of our streams look like in farmland. This is a farm just down the street from me. I have lived there 13 years, and I have watched this guy's farm wash away every time it rains. Why? Because he insists on having his cows and his sheep just be able to walk right into the stream there. Where is this washing? It's washing down into the Chesapeake Bay, and then we all wonder why the Chesapeake Bay is dying. This is so easily corrected. It's so easily corrected. We need to be doing that. What about power line cuts? We have 300,000 kilometers of power line cuts in the US. So there's one right there. And your initial take might be, well, look, that's fragmenting the forest, and in many places it does separate the forest, but it can separate the forest with a habitat that used to be more abundant and natural in its own right. And that would be scrub habitat. So here's a power line cut in which we have very nice scrub habitat. And scrub is something that has disappeared. It's one of the most rare habitats that we have left in this country because we don't allow it to exist. But there are birds and many things that only breed in scrub habitat. The golden-winged warbler, for example. If you want to see breeding golden-winged warblers in Pennsylvania, you go to a power line cut because it's just about the only place they are. If we treat our power line cuts like this, it works. If we treat them like this, it doesn't work. There are power companies doing it responsibly, there are power companies doing it irresponsibly, and I'm not sure how much they understand that or know that. It is very easy to fly over these areas with planes and just spray. I get it that we can't have the trees growing up to the power lines, but you can do it in other ways. I'm not sure that it's more expensive either, and it would be very important green infrastructure in this country. Roads as convenient corridors. We mentioned we have four million miles of roads. This is the highway to heaven there. It goes right up. And look, they go through viable habitat. Most people don't want to live on a major roadway. So that could be an area that we get not too great pushback on. This is what most of our major roadways look like. If it has a median strip, it's mowed. It's always mowed on the side there. If you've got four million miles of road that's mowed on each side, that's eight million miles of mowing which takes a tremendous amount of energy, tremendous amount of fossil fuel inputs and so on. This is the Taconic parkway in New York. And this is the way we treat our median corridors because... we always have. That's why. You know where this is? This is the Taconic Parkway in New York, and there is that median strip. The other road is on the other side. The very same highway. This is about one mile up from where I took that first picture which says, look, we can have viable habitat in the middle of the roadway here. Why does it look like this in some places and like this in other places? This road was built in the, I don't know, '20s and '30s. And I think they just went through a patchwork of farmland and forest, and when they got to forest, they left it. When it was farmland, they started mowing it. But they could have put the trees back. They could have. And they've been mowing it now for approaching a hundred years of mowing. As some people will say, if you have it like this, you're creating ecological traps. You're inviting animals in so they can get clobbered. We need to study that a lot more closely. There was one study and that wasn't the major question they were asking. I think it was out of Canada. And they did not find more carnage on the side of the road where you had habitat. But I admit we don't want to be doing that. This is Eleanor Deidrick. I just want to use Eleanor as an example of what one person can do to really change the way we treat our roadways. She lives in Florida and she got tired of looking at rare species of plants in Florida being mowed down mindlessly right as they're coming into bloom on schedule everywhere. Florida has, what, 12,000 miles of roadways. So she started asking questions. Do we really need to do this? What she suggested is we have this little beauty strip here. But look at all the area they're not mowing anymore. And you can have viable wildflower corridors in the areas of roads. This is Florida now. Florida is a conservative state, but Eleanor has talked to everybody, I think including the governor, and she's having success. She is now hired part-time, I think three days a week, to oversee the conversion of much of the area that is being mowed in Florida into wildflower preserves. All kinds of people are on board, and it's all because Eleanor said why are we doing this? We can do that in every state. We can do that in every state because Eleanor says so. But again, here's that problem. Are we creating ecological traps? We need to look at that more closely. But even in areas where there is not high speed traffic. This is a rest stop along the Pennsylvania turnpike. I don't know how many acres of lawn that is, and is that so we can walk our dogs? As if we put a tree there, we wouldn't be able to walk out dogs? I don't know.

LAUGHTER

Mowed religiously all summer long. And you can go everywhere and you find huge areas of lawn that are not going to be high risk in terms of wildlife corridors. We have looked for biodiversity in lawn.

LAUGHTER

We haven't found it. This really is a real study. We're trying to compare the diversity in a lawn with meadows and forests and everything else. So we can do a lot better. We can take tremendous number of acres out of lawn and put it in productive habitat without loss to anybody. What about rangeland? Few people understand how much area of the US is in rangeland. 770 million acres. That is 18.3 times bigger than Wisconsin. It's got a cow on it. Does that need to be bad? No, it doesn't need to be. Our grasslands have never existed in North America without large ungulates grazing them. It is part of the ecological formula that keeps those grasslands being replenished and diversified. So right now we've gotten rid of all of our ungulates except bison. I would love to exchange bison for all the cows, but that's another story. But here we have regular cattle. These are sunflowers, and this is an experimental range in Nebraska that just shows you can graze responsibly. You can make nice beef without wiping out the habitat. This is now excellent grassland habitat that connects actual preserves. And you can do that everywhere over 18 times the size of Wisconsin. Unfortunately, this is typically what our rangeland looks like in the west. We overgraze it. There's not enough water, and there's about nothing there. That is so easily turned around with proper range management. Okay, so we've got mountain ridges, we've got riparian corridors, roadways, power lines, abandoned rail lines could be another opportunity, rangelands. These are all convenient opportunities to build biological corridors. Unfortunately, with all those convenient opportunities, we still don't have them every place we need them. So what should we do? Well, what I would like us to do, and you already know this, is to restore the areas that are in between those isolated habitat fragments, and that's where we live and we work and, to a lesser degree, where we farm. So that we can build effective corridors pretty much everywhere. So if this is the standard model of biological corridors. The word corridor is misleading. It suggests we're just building areas so the animals and plants can move between viable habitats. I don't want to do that. I want to make it so they can move but also they can live in there. We have to restore viable habitats that support life, otherwise it's not going to work. So if this is the standard approach to biological corridors, then this would be better, and this would be better yet. Maybe these are major cities in here, but who's in here? That's where we're living? And putting dots here, so in an eastern deciduous forest, that's what it ought to be. But in a prairie situation, that's what it ought to be. You have to rebuild the biome where you belong. But it's no longer paved over. So, again, we can save nature, and, thus, ourselves because we're not going to be here without nature, if we learn to live with it. What should we build our corridors out of? Of course, we have to build them out of plants. The more plants you put in your corridors, the more other lifeforms you're going to have. That's, of course, because plants are the first trophic level. They're the organisms capturing the energy from the sun and turning it into food for everything else. It's plants that allow us and everything else to eat sunlight. Another important ecosystem service. We're not going to eat sunlight without plants. That will be very difficult. And they do that by capturing the energy or capturing carbon dioxide from the air, combining it with water from the ground, producing the oxygen that we all still need, and now the energy from the sun is transferred to the carbon bonds of simple sugars and carbohydrates, which happen to be the basis of every food web on this planet with the minor exception of some sulfur based food webs at the bottom of the ocean, and they're not going to support anything. Let's just generalize and say plants are making all the food for us and for everything else. Plants are also providing physical structure. So they're providing the housing, the shelter for animal life. So if you're talking about animal populations, plants are quite literally a matter of life and death. If you have them, you have the option for life; if you don't, you don't. Which means we can look at the amount of plant life in a given space and estimate what the carrying capacity of that space is. How much life can be sustained in this particular space essentially forever? And it can be sustained there because the life is not degrading the resource base of that space if it's below the carrying capacity. We can plot it. We can say, well, we've got this many plants. That's the carrying capacity. And I like to think of carrying capacity as if it were the principle in an ecological savings account. So think back to when we used to have savings accounts. They used to generate interest, and we could live off that interest forever as long as we didn't dip into the principle. It's still how the carrying capacity works. We've got plant populations generating ecological interest in the form of food and shelter. And animal populations can grow in cycle using that food and shelter essentially forever as long as they don't reduce the amount of plants making the food and shelter. If something does reduce the amount of plants making the food and shelter, there will be less of it and any animal population depending on it will crash down below the new carrying capacity. And, of course, if you get rid of all the plants, you get rid of all the food and all the shelter and all the animals. Now this is an eastern deciduous forest. This is what it looks like back home for me. Very high carrying capacity because it's making so much food and so much shelter compared to a suburban yard. For obvious reasons. We have taken the plants out of this space. It's true that the grass is a plant and the birch tree is a plant, but it's a tiny fraction of the plant life that used to be there generating just a tiny fraction of the ecological interest that it used to generate. So it's supporting just a tiny fraction of the animal life that it used to support. If we put the plants back into neighborhoods like this, we really can recreate ecosystem function. And as I said before, the goal here is not to recreate exactly what was there 700 years ago or 200 years ago, and people will say, well, we don't know what it used to be, therefore we shouldn't do it. So forget that argument. It's just to put enough plants back to create ecosystems function. That's the goal. So will any old plant due? Well, you remember from the first talk that, no, all plants are not equal in their ability to support food webs, and that's why we're putting them back there. We're putting plants that are going to be good at contributing to local food webs and local ecosystem function. Let me develop this a little bit more. This is a picture of Ugly Agnus here, elaeagnus. It's a typical plant brought over as an ornamental. This was brought over about 120 years ago. And it's also a good example of an invasive species. It has escaped our cultivated plantings and is now aggressively displacing native plant communities. That's what an invasive species is. If Ugly Agnus was the ecological equivalent of the native plants it's displacing, that would be okay. Our ecosystems would look like Ugly Agnus, but they still would function just as well. So that becomes the question. Is Ugly Agnus as good at supporting local food webs as our native plants? And you already know the answer to this. No, it's lousy. Even though it's been here 120 years, very few insects have been able to adopt it as a viable host plant. So Ugly Agnus and all the other non-native plants that we've brought in are supporting very few insects. But wait. Didn't I say that increased diversity, as you add species to an ecosystem, doesn't that increase ecosystem function? If we have 3,300 non-native plants in this country and if we haven't lost native plants, we have increased the diversity of the plant life out there by 3,300. And I hear this argument. They say diversity is a good thing. You just said it's a good thing, so why aren't these 3,300 species increasing ecosystem function? Well, because what Robert MacArthur was saying is that as you increase species that are contributing to your ecosystem, ecosystem function goes up. But if you're increasing the number of statues in your ecosystem, ecosystem function doesn't go up. You've got to have species that are contributing. Just being a species and existing there is not going to do it. And that's a piece of the puzzle that a lot of people continually forget. So there you go. If a non-native plant captures the energy from the sun, and they do, they're all photosynthesizing, they're all growing and they've got all that energy in their leaves, but if they don't pass it on to all the things that need that energy, then it ends right there. That's the end. There's no viable food web about it. That's what I mean by contributing to local ecosystems. They've got to pass the energy on by allowing something to eat them. So, diversity builds stability when that diversity is contributing to stability. Let's talk about stability a little bit. Let's talk about complex food webs versus simple food webs and compare their stability. There's two ways that complexity builds stability in food webs. First of all, if you have a complex food web, you've got a food web constructed from many species. Then, if you've got a predator eating those many species, you've got prey alternatives. So the predator doesn't have to eat just one thing. It can eat a whole array of choices. And if one of those prey species disappears, it still has a variety of other things to choose from. Also, it allows prey switching. So you've got a predator out there and it's eating one particular type of caterpillar, as that caterpillar gets more and more rare, it won't continue to look for that until it gets the very last one. It will go to the next most common caterpillar. It will switch off of it and allow this one to recover. So diversity allows all of those species to coexist with each other by the predator going to the most common one all the time. So you never force one to extinction. Let's use the wood thrush as an example here. So here we've got the common wood thrush feeding its baby. That looks like a blinded sphinx there. And these are just a bunch of hypothetical caterpillar alternatives. I think there are 11 species there. We would call this, it's actually a pretty simple food web, but I'm going to call it a complex one compared to one where the wood thrush just has two opportunities, two prey opportunities. So if we go to the complex food web here and we take away, these are Promethean moth larvae. Let's eliminate them. Look, the wood thrush still has 10 other alternatives. You might have a bad year for the Promethean moth. It's not in your local food web, but it can still bring its offspring food because there's enough prey alternatives. If you have a very simple food web and you eliminate the white-dotted prominent here, now the wood thrush has got to do everything based on polyphemus moths. It's highly unlikely you will have enough polyphemus moths to do that. So, simple food webs are very unstable. They often crash. And that's why we need to build diversity into our biological corridors. And, of course, we're not going to be able to do that if we ignore the specialist insects that have a relationship with particular plants. But specialization is risky in today's world, and there's no better example than our friend the monarch butterfly right now. Specialization has been a curse to the monarch. It's a specialist on milkweed. And, of course, we have taken the milkweed away, so maybe we're the curse to the monarch. But this is the perfect example A lot of people will say, well, our insects will adapt. Okay, I'm waiting for the monarch to start eating oak trees.

LAUGHTER

I'm waiting for this adaptation. You know what's going to happen? It's going to disappear first. Adaptation does happen but not at the rate at which we're changing the landscape. You don't eliminate a host plant in a few years and say, hey, adapt to it. So we're watching the monarch disappear because we have removed milkweed from our ecosystem, particularly our Midwest ecosystems. We now have clean farming techniques. We have round-up ready corn and soybean. So we don't have any weeds in the fields anymore. We've also taken away CRP land and put it into the production of ethanol, which means we're farming right up to the woods, and where we're not farming we don't have viable habitat anymore. Does that mean I would ban genetically modified ag products right now? We don't have to go there. That would be a 30-year fight. All we need to do is say, hey, you're going to use this product, you have to have a 200-meter by four foot strip of milkweed. Maybe per every acre you're doing this. The farmers could do that. Look at what they're getting out of this land right now. Nothing. So they're not losing productivity. It would be an easy solution because we got tens of thousands of square miles of farmland that is being treated like that. If we want to bring the monarch back, and we certainly do, right now the immediate thing we can do is put the milkweed back in our home gardens and that will work if enough of us do that. But we've got to get these guys putting it back as well. There is no good reason why they can't do that. Okay, lots of specialists out there. This is another advantage of specializing. This is the double-toothed prominent, and it is a specialist on elm. So not only is it good at getting around the chemical defenses of elm, it started to look like the edge of an elm leaf. Why does it want to do that? Because you've got all the birds out there trying to find these caterpillars. And you might think that birds hunt caterpillars, but they don't. They hunt caterpillar damage. They're looking for holes in leaves. And when they find a hole in the leaf, then they search around and try to find all the caterpillars that made that. So this guy is sitting in the area that he has just eaten, and he's pretending he's the edge of an elm leaf. So he says there's no holes here, and the bird says okay, and flies on. And this works for the double-toothed prominent as long as we have elm. But if we lose it through the Dutch elm disease or if we lose it because we planted the crepe myrtle or the zelkova, we don't have the double-toothed prominent. Not just caterpillars are specialists. This is the elderberry beetle. It only eats elderberry. The dogbane beetle only eats dogbane. Sumac flee beetle only eats sumac. This is a leaf-footed bug that only eats ash. So, unfortunately, you've got ash bore in Wisconsin now, or the emerald ash borer. If you lose your ashes, you will lose this species. You'll lose the great ash sphinx. You'll lose the wave sphinx. I think there's 44 species of caterpillars that only eat ash. They will all disappear. And this is where that 90% of specialists comes into play. 90% of the insects that eat plants are specialists like this, so if we create those novel ecosystems I talked about before that don't support all of these insects herbivores, we're going to lose 90% of them. Not good news. So if we want to restore the ecological integrity of this space, and we do, we have to do two things. We have to put the plants back or it can certainly never be a viable corridor that way, and we have to use productive plants. So is the solution simply to use native plants? Well, I showed you this list earlier. You can finish memorizing it now.

LAUGHTER

Last time we talked about comparisons between native plants and non-native plants, but let's look within native plants now. Let's compare tulip tree, good native plant, in terms of ability to support caterpillars with -- the oaks, you already know that's number one, 557 species up there. But look where tulip tree is. It only supports 21. And it's a native plant. It is a good native plant. We want it in our forests. We don't want a monoculture of oaks or anything else. But if you had space in your yard or your landscape to put a single tree and you wanted to put the most productive plant there, just choosing a native is not good enough. Look at this list. Should it be an oak or should it be a tulip tree? That is what the list is for. What about a redbud? Everybody loves redbuds because they're beautiful and we love beauty and I understand that. But what is its contribution, it's contributions to early season pollinators are obvious. It's great for early season pollinators. So that's one reason to include it in our landscapes. But what is its contribution to food webs compared to something like black cherry, which you already know is number two on our list? Native prunus, 456 species of caterpillars supported, and native redbud only 19. Only 19. So it's very low in terms of supporting food webs compared to a plant that most of us don't like, or at least landscapers don't like black cherries. A lot of people, particularly in the east, they'll hire a landscape, he'll go around the property, and the first thing he'll do is chop out all the black cherry. And they say, you don't want them because they're weeds. A weed is a plant out of place. If you're trying to rebuild viable food webs in your yard, black cherry is not out of place. Native prunus are not out of place because they're number two on our list. And if you include them in your yard, these are some of the things that are going to become part of your yard. If you're interested in getting your kids interested in your yard to unplug and run outside long enough to see something, tell them to find the cecropia moth. The favorite host plant of the cecropia moth is black cherry. That's what the larvae look like. Tell them to go outside and find the egg, find the cocoon, find the larvae, find the adult. If you have a population of cecropia moths in your yard, you will have some form of that life history in you yard at all times, and if the kids find it, believe me, they're hooked. These are giant silk moths, and they're really fun to play with. If you have a butterfly garden, what do we do? We plant nectar plants and hope that we're attracting butterflies from someplace else. Tiger swallowtail certainly one of the main ones that we want to attract. But when we approach butterfly gardens that way, I ask, who is making the butterflies? Well, in this case, the favorite host plant for tiger swallowtail is black cherry. And you'll notice if you go through the list of host plants for our favorite butterflies, most of them are woody species, they are not big flowering herbaceous plants that we all think of as nectar plants. So butterflies need both larval hosts and nectar plants, and you can have both of them in your habitat. The black cherry doesn't have to be in your butterfly garden, but it needs to be in your landscape. Don't depend on the wood lot two miles down the road to make your tiger swallowtails because somebody else is going to build a skyrise there or something. And then, of course, you get all kinds of other things when you have a really productive host plant like that in your yard. You can have the -- moth if you have black cherry and it's beautiful larva. You don't want to pet that, but it is beautiful to look at. You could have the dowdy pinion. You might say, I don't want the dowdy pinion.

LAUGHTER

But if you notice most of the caterpillars my chickadees were bringing back, they were dowdy pinions because it's a specialist on black cherry early in the season, and that's keeping these chickadees alive. You could have the yellow-shouldered slug. You could have the coral hairstreak or the petal caterpillar or the red-spotted purple, which is a specialist on black cherry. It's larva that looks like bird dung.

LAUGHTER

You could have the Promethean moth and its beautiful larvae or the purple-crested slug or the crocus geometer, the spotted --, the... The senior moment caterpillar.

LAUGHTER

Saddleback, the saddleback. The wavy line heterocampa, the white furcula, the spiny rose caterpillar. Here's our friend the tufted bird dropping moth that the -- were bringing back. The --, the yellow-haired dagger moth, long-winged dagger moth, Radcliffe's dagger moth, the interrupted dagger moth. You cannot have the connected dagger moth unless you put willow in your yard because that's its favorite host plant. Or you could have the nascent slug and 400 and some odd other species of bird food just by including that one really productive plant in your ecosystem. If you put your burr oak in your landscape, what are you going to get? You could have the puss caterpillar, the polyphemus moth, the buck moth, the white-marked tussock moth, the saddle prominent, double line prominent, white-dotted prominent, the checkered fringe prominent, the laugher, the lace caterpillar, the oblique heterocampa, the white-blotched heterocampa, the variable oakleaf caterpillar, the banded tussock moth, hickory tussock moth, the spiny oak caterpillar, the banded hairstreak, yellow net caterpillar, the smaller parasa, the unicorn caterpillar, the crown slug, the hag moth, the streak dagger moth, red-humped oakworm, confused woodgrain, and the spun glass slug, which I think is the coolest caterpillar in North America, and then 500 and some odd others. You know where I took every one of those pictures? My front yard.

LAUGHTER

You are allowed to have productive plants in your front yard. I give you permission. Why do we want all these insects? Why do we want all these insects? Well, we already talked about it. Because so many animals are eating these insects. I can't emphasize this enough. Those spiders and those predators and those frogs and those toads and all those amphibians and the fish and the lizards and the bats, all of these things, our rodents, you're not going to have rodents without insects. They're not all seed eaters. Our skunks and our possums and our red foxes and our bears and all these guys. Just like the-- I can't give two talks in a row, come on. What is that guy? >>

INAUDIBLE

>> Sharp-shinned hawk, yes. Then the guarder snake. It's not eating insects directly. It's eating the frogs and toads that eat the insects. So you need to have these viable food web, you need the insects. You could use particular plants that are really good at emphasizing or bringing the type of nature that you like into your yards. Now, I spent the first 25 years of my career taking pictures of insects because they're easy and they don't move. I've graduated to birds. You've noticed that. And this is a great plant to bring those birds into your yard. It's a productive plant in the spring. Very beautiful bloom. Makes lots of nice insects when those birds are reproducing, but then that bloom turns into a heavy berry set in mid-July and those same birds come back to eat the berries. I put this particular plant next to my bathroom window. It has grown up past my bathroom window. So every time I look out that window, I see the birds that are in that tree. And I've been trying to make a photographic record of all the species that are using that. This is what I have so far. This is the orchard oriel, the cedar waxwing, the catbird, bluebird mommy, bluebird baby, red-bellied woodpecker, brown thrasher, right? >>

INAUDIBLE

>> Thank you. I really do know this.

LAUGHTER

This is a mockingbird. Came in to get a berry but found an insect. Will always take the insects and leave the berries because they're much better food. A grackle, a warbling --, a peewee, a red-eyed vireo, a phoebe, blue grosbeak, robin, white-eyed vireo, kingbird. And then the birds that are not after the berries but are just after the insects on this plant, like the yellow warbler or the gleening insects from the leaves. And even my butterflies love to sun themselves on this particular plant. Now, if you don't want to do your birding while you're going to the bathroom, go to the bedroom.

LAUGHTER

Look at the elderberry, and you get the same cast of characters. So you can use these plants. While you're building your biological corridor, you can entertain yourself. You can use these plants like a remote control. You can turn nature on or turn it off, depending on whether you use them and where you put them in your yard. But, of course, they make leaves, and those leaves fall where? On our lawn, and we all freak out. We get our leaf blowers and our rakes and we rake up all the leaves, put them in garbage bags as if it was trash. Then we run to Home Depot and we buy mulch, we buy fertilizer.

LAUGHTER

We buy hoses trying to replace the ecosystem services that we just threw out. What we can't buy are the arthropods that live in those leaves. And why do we do that? Because, well, heaven forbid, we can't have leaves on our lawn. My son bought a house two years ago, I guess, and the first fall he was in that house, he called me up and he said, dad, I've got too many leaves. I said put them in the flower bed. They're the perfect mulch for your plants. They'll love it. He said, I don't have enough flower beds. I said, exactly.

LAUGHTER

That's how we shrink the lawn. This is an oak tree here, and those oak leaves fell down here. I know this guy. He didn't rake them up, and look what came up. He also didn't plant any of those ferns. They came up on their own. This is now a perfect spong. When it rains, the water does not run off into the sewer. It soaks in, replenishes the water table. And he's also created the, well, before I get to that, you can, if your neighbor sees this, they might think you moved out or that you're not landscaping anymore. So put a grass path along here and that formalizes it. It's a cue for care that says, I am landscaping. This is intentional. I am a good citizen; I'm not a communist.

LAUGHTER

And when you do that, you created the perfect, oh, yes, Abe Levitt told us in the '50s if you didn't have a perfect lawn, you were a communist, and everybody believed him. But you created the perfect foraging place for our poor wood thrushes. They're down 50% from what they were in 1966 because they forage for arthropods in leaf litter, and we're throwing it out all over the US. So when we build landscapes like this, this is the pond at Mt. Cuba Center if anybody has ever been to that in Delaware, it's a DuPont estate that is 500 acres and it is essentially all natives. Excellent place to see how you do this in the east. When you build landscapes like this, you can create, you can introduce three things into your

life

surprise, anticipation, and entertainment. By surprise I mean you can't walk into a landscape like this without seeing something you didn't expect to see. And, believe me, you can't. I have seen a lot of things in my landscape, and still, every time I go out, except when I have a broken ankle, I see something that I didn't expect to see, and to me that's really rewarding. It emphasizes the diversity of life and how wonderful things are out there. Anticipation, throw away you calendar. Nature does things on schedule. And you can anticipate these things. We know when spring has arrived at our house when the woodcock shows up. I come home from work, I ask Cindy, have you heard the woodcock? Not yet but we're anticipating it. And then it happens. And that, to me, tells me the world is still working. With all this bad news out there, nature still works and that is really reassuring to me. We know that spring really gets going when the toads start singing. We know that August gets going when the white-lined sphinx starts to pollinate our evening primrose. We know that fall has come when the junco shows up, and not before. I don't care what the calendar says. As far as entertainment goes, we have a bottlebrush buckeye in our yard, and I walked by it this summer and 17 swallowtails flew up from that one plant. You cannot have, you cannot walk through a cloud of 17 swallowtails without a smile on your face. That's entertainment. I don't think you can do it. I don't think you can do it. So more and more people are actually, and you people know this, you're doing it yourself, you're putting more native plants, productive plants, into their yards, creating viable corridors, and that has allowed us to measure what the benefit to biodiversity is when you actually do that. So this study is a few years old at this point, but one of my students, Karen Burkhardt, did her senior thesis on this. She compared six houses where the homeowners had done a makeover. They put in a lot more natives. None of them 100% native, but there's a lot more than there used to be. With six traditional landscapes, and a traditional landscape back east is typically a higher percentage of native canopy trees and then an awful lot of non-natives in the shrub and understory layer. She controlled for everything, but the most important thing she controlled for was the amount of plant biomass. She was not comparing bare lawn with a forest and saying, look, there's more in the forest. All these properties had the same amount of plants in them. The only thing that differed was the percentage of native plants. And we weren't looking at productive versus non-productive native plants. It was simply native or not, so it was pretty crude. And this is what we got. She looked at caterpillars and breeding birds. She found significantly more caterpillars in the primarily native sites, more species of caterpillars, more birds, more species of birds. There were some birds on the traditional landscapes, and she looked at what they were. They were largely house sparrows, house finches, starlings, a few pigeons thrown in, all invasive species of birds that do really well, essentially, on our garbage. And then she looked at the plants of conservation concern as designated by Partners in Flight. So these are the birds that are in trouble where she did this particular study, and when she looked only at those species, she got the biggest response of all. So the birds that needed the help the most, got the help the most from these residential makeovers. And as I said before, none of them were completely native. Another good part about this study is that it happened quickly. The made-over landscapes that she looked at were young. They had all been done within three years of when she did this study. So all the things she saw coming to these landscapes came quickly, and that's good because we're a society of instant gratification, and if it took 50 years for things to colonize something, nobody would bother doing it. But it doesn't. It happens right away. Okay, final thing I'm going to talk about quickly is what a lot of people worry about. People garden so they can have beautiful plants in their landscape. And they say, well, if I put all these native plants in my landscape and all of these caterpillars come and eat them, I will have holes in my leaves. Or worse yet, they'll be defoliated. So they worry about that. That's part of the formula. You put the native plants in, the herbivores come and eat them, but then all the things that eat those herbivores come and eat them. That's the completion of this balanced food web in your yard. And if you do that successfully, you will not have more damage than a traditional landscape. And we've actually measured it. Same amount of damage. Here's an example. This is a tobacco hornworm, which was eating one of my tomatoes. If you grow tomatoes, you probably know this insect. I went out to take its picture, and it had all these cocoons on its back. A lot of people think those are eggs, but those are the cocoons of a braconid wasp, a little parasitic wasp, and the larvae of those wasps have already tunneled out the insides of this guy. You can see he's shrinking like an accordion. So he's alive but he's really dead. He's not going to eat anymore tomato plants. This is a pteromalid wasp. It's a parasitic wasp that lays eggs in braconid wasps. So this guy is making sure that Cindy and I don't have too many braconids at our house. And the braconids are making sure that we don't have too many tobacco hornworms at our house. And the tobacco hornworm is making sure we don't have too many tomatoes.

LAUGHTER

life

So why do we have these natural enemies when maybe you don't? That's a good question. Two possible answers. One is that you're not going to have nature enemies if they have nothing to eat. They will leave. So, what is going to feed these guys? It could be tobacco hornworms. If you have enough tobacco hornworms all season long, they will stick around and you'll be in good shape. But I'm thinking about our yard. In the 13 years we've been there, we have only seen four, and he's one of them and he's dead. So that's not enough to keep these natural enemies around all the time. But this is a type of sphinx moth. See his little horn there? And these braconid parasites hit all of the sphinx moths. And we have 18 species of sphinx moths at my house because we've got the native plants that support them. We've got the blinded sphinx. This was the guy that white-eyed vireo was bringing back because we've got black cherry. We've got the four-horned sphinx because we've got American elm. We've got the hummingbird sphinx moth because we've got viburnum dentatum. We've got the hog sphinx because we have Virginia creeper. We've got the snowberry clearwing because we have coral honeysuckle, the native honeysuckle. We've got the wave sphinx because we've got ash. We've got the Pandora sphinx because we've got Virginia creeper again. And I've got Virginia creeper on my back porch because I planted it there. Why would I do that? Because I wanted that moth to come and lay an egg there so I could take that picture.

LAUGHTER

life

These guys come in red, they come in yellow, they come in brown, they come in green, and they come covered with braconid cocoons. They're pretty big caterpillars and people said, aren't you afraid they're going to eat all your Virginia creeper?

LAUGHTER

life

Nope, I'm not afraid. Virginia creeper grows really fast. And in the 13 years we've been there, we've only seen those four. And you've now seen them too. Why is everything so rare at my house? Well, look at all the things that are killing them. It is really difficult to reach maturity at my house.

LAUGHTER

life

We also have other predators. This is the cogwheel bug. It's the largest assassin bug in North America. And it's eating a fall webworm. Nobody likes fall webworms. This guy is helping out as best he can. And we have other species of breeding birds. All the birds are bringing back 300-plus caterpillars to the nest every day. But you're not going to have those breeding birds if you don't have the caterpillars to support them. But if you do, you're not going to find any caterpillars. They get them first, believe me. So, how effective can our residential corridors be? This is the last thing I'm going to leave you with. An example from southern Florida where residential neighborhoods, homeowners have accidentally saved the atala butterfly from extinction. So, how did that happen? This is the atala butterfly. It is a lycaenid that only occurs in the southern tip of Florida. Beautiful as an adult, beautiful as a larva, and beautiful as a chrysalis. And like those 90% of the insect herbivores I talked about, it is a host plant specialist. In this case, an extreme specialist. It eats one species of plant, a native cycad called the coontie. Coontie has an interesting history. The Seminole Indians used to use it as a source of starch. They would pull it up by the roots and pound the roots into a starchy paste, and then they'd add it to other types of foods. And when the settlers came, the Seminoles taught them how to do the same thing, and the settlers loved coontie as well. They loved coontie so much that they ate all of it. No more coontie in the wild, which means, of course, the atala butterfly has nothing to eat and it disappeared. When we had, in the '70s we came up with the endangered species list, it was 1974, there was a desperate attempt to get the atala listed as an endangered species, but nobody could find it. You can't list it as endangered if it's already extinct. So they got it listed as extinct instead. Well, about that time the landscaping industry discovered coontie as a viable landscape plant. There were a few plants left in residential gardens, and they started to promote them. And in no time at all, coontie was a standard landscaping plant throughout southern Florida. And lo and behold, the atala butterfly showed up again. Nobody knows where it came from. Probably a population hiding deep in the Everglades that nobody knew about. But it's now a fairly common butterfly in southern Florida. What I really like about this story is that it truly was an accident. They never got this species listed as an endangered organism. Not one dime of conservation money was spent saving this endangered species. And yet, it happened by adding a single species of plant to our residential gardens. If we can do that by accident, think of what we can do if conservation became a goal of our residential landscapes. So I think we're on the cusp of a new environmental ethic that is going to change the way we approach nature in the old days. And I am really hoping, and I do believe this is going to happen, that this is an ethic that's going to be adopted worldwide. Historians might come to call this the ecocene. Fortunately, our environmental insults of the past and of the present are reversible. Again, if we form a new relationship with nature and learn to live with it. The future can't be like the past because not only will we do in nature we'll do in ourselves. We will be able to generate all the ecosystem services that we need if we live amidst the natural systems that produce them. It's really that simple. Our age old need to destroy the life around us in order to survive must be, and I think it will be, replaced by the ethical and ecological imperative to sustain it. And fortunately, nature is really malleable. It's resilient. It's forgiving. I do believe it's going to give us one last chance. A lot of people say our kids are the solution. This is my grandson Oscar.

LAUGHTER

life

And he is very much into nature these days, much more than his peanut butter and jelly sandwich. And people say if we train Oscar, we are done. No, we're not, because we can't wait for another entire generation to go through. So this is on our plate now. We have to train ourselves. That's what we're here for today. Thank you very much.

APPLAUSE