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cc >> I'd like to introduce our keynote speaker. I've had a chance to talk and meet Doug several times. I've heard him speak twice, and I can hardly wait to hear him again this morning. He's extremely inspiring. He's going to talk about the vital new role of the suburban and urban garden and how using native plants in our neighborhoods and community landscapes we can restore vital ecosystem functions where we live and play, and that as gardeners and stewards of our land we have never been so empowered. Dr. Tallamy, Doug, is professor of the Department of Entomology and Wildlife Ecology at the University of Delaware where he has authored 79 research articles and has taught insect taxonomy, behavioral ecology, humans in nature, and other courses for 32 years. He's also director of the Center for Managed Ecosystems. Chief among his research goals is to better understand the many ways insects interact with plants and how such interactions determine the diversity of animal communities. His book, Bringing Nature Home, How Native Plants Sustain Wildlife in Our Gardens, was published by Timber Press in 2007 and was awarded the 2008 Civil Medal by the Garden Writers Association. Doug was awarded the Garden Club of America Margaret Douglas Medal for Conservation in 2013, and he is an honorary director of Wildlands. And I have no idea how he does it, but he gives 80 to 100 presentations a year. Just a reminder, he will be giving his presentation in two parts this morning. We ask that you hold your questions from this first part until the end of the second part, and that will begin

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30. And now, please welcome Dr. Tallamy for part one of his talk, "The Value of Having Native Plants in Our Home."

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>> If you're wondering why I'm sitting down, I broke my ankle. It's fun but not that much fun. I wouldn't advise it.

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All right, anybody recognize this beautiful creature? >>

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>> This is resplendent quetzal, which is an endangered bird in Central America. It's an endangered bird because it has a very specialized diet. It's not going to exist where you don't have fruits from the wild avocado tree. And, unfortunately, we have cut down most of the avocado trees. So we finally figured out if we want to save the quetzal, we're going to have to plant avocado trees. And that's what these young folks are doing right here. And this conservation scenario is repeated time and again in tropics. If we want to save the great green macaw, we have to have the mountain almond trees that they nest in in our forests. And, unfortunately, same thing, we've cut down most of the mountain almond trees. So people are working to put them back. If we want to save the jaguar, we have to plant a particular species of palm. Why? Because they make a particular type of palm nut, and the particular type of palm nut is the favorite food of peccaries, and that's what the jaguars eat. You're not going to have healthy jaguar populations without peccaries. So specialization in the natural world, especially food specialization, is the rule. It is not the exception. And specialization always starts with native plants. Now, a lot of people think that specialization is really a feature of the tropics. You don't have much of it in the temperate zone. So this is where you're going to find specialization. And, of course, they are right. It's very common in the tropics, but it's also very common in the temperate zone. And some of our most specialized relationships are occurring right in our yards. And this is one of them. This is the bolas spider. It's called the bolas spider because it makes a single strand of thread with one sticky glob of glue at the bottom of that. This is the female suspended from a river birch leaf right off my back porch. And she'll come down right if it gets dark, and then essentially go fishing with this one glob of glue. She sits there and she lowers it and raises it just like I used to do when I didn't catch anything.

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And the first time I watched this, I looked at her and said, you're not going to catch anything that way. And about 15 seconds later, a moth flew right into her little sticky glue thing and she reeled it in and wrapped it up and laid her egg mass on it. What I didn't know at the time is that that was no accident. While she was fishing with her little sticky bolas, she was also releasing the sex pheromone of that moth. So that's a male moth, and she was pretending to be the female of that species. She had mimicked the sex pheromone in a highly specialized way, and that moth, of course, thought she was a female and that's why he flew in. Every species of bolas spider has mimicked the sex pheromone of one species of moth. So you will not have bolas spiders in your yard if you don't have the moth that that particular species has mimicked. And you're not going to have the moth if you don't have the larval host plant that supports that particular species. So specialization does happen in the temperate zone. Here's another example. This, of course, is phlox divaricata. It spread wonderfully in your garden by seed if it's pollinated. But if you look at those flowers, that's a tiny little corolla there. I have watched native bees try to get their tongues into that. They can't do it. It's too deep and it's too small. So what is pollinating our phlox? It turns out it's day flying sphinx moths, particularly the hummingbird sphinx. So here's its long tongue aiming for that little flower there. He's got it buried in, and when he withdraws it, it is covered with pollen. And then, of course, he moves to another flower and pollinates it very efficiently. But you're not going to have hummingbird sphinx moths if you don't have native viburnums because that is what supports the larva of that particular moth. So that's got to be a feature of your landscape. Again, this specialization always starts with plants. You're not going to have the clouded sulfur. Everybody see it there? Right there, hiding right there. There he is a little bit more obvious. It's a beautiful larva of one of the sulfur butterflies that is using the crypsis of yellow, in this case, partridge pea but also senna flowers, yellow legumes, and they won't exist unless you have those yellow legumes in your yard. You're not going to have reproducing May apples, make their little flower there and it turns into a little fruit, if you don't have box turtles because the box turtles eat those fruits, and I have been told those seeds won't germinate unless they pass through a box turtle's gut. So you've got these relationships that are highly specialized that are occurring right in our yards. And even animals we don't think of as being specialized actually have very specialized relationships with plants. Animals like the chickadee. It's the Carolina chickadee. We all think of chickadees as seed-eaters because they do eat seeds. They're at our feeders all winter long. But when they are making more chickadees, they are not seed-eaters. They all the sudden become food specialists. They are feeding their young caterpillars. Even though they have the option of feeding them grasshoppers, there are grasshoppers that mature in the spring when the chickadees are reproducing, or crickets or -- bugs or syrphid flies or snipe flies or cicadellidae leafhoppers or click beetles or treehoppers or sow bugs or centipedes or millipedes or spiders. All of those things are available for those chickadees to feed their young, but they don't. They only feed their young caterpillars. Which means if you do not have caterpillars in your yard, you're not going to have chickadees, breeding chickadees. And what it really means is if you don't have enough caterpillars in your yard, almost enough isn't good enough. You have to have enough. So what is enough? How many caterpillars does it take to make a clutch of chickadee? It takes a lot.

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Because you've got the male and the female cooperating and bringing back these caterpillars, and they can bring back a caterpillar to the nest once every three minutes. In one 27-minute period, I had a pair breed in my backyard so I was there with my camera and I was actually recording what was going on, in a 27-minute period they brought back 30 caterpillars. So how do they do that? They do that by bringing back more than one at a time. And sometimes a whole bunch at a time.

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And they did it from 6:00

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00 PM. Now, occasionally they will bring back an adult caterpillar, a moth, but that is not common. It is typically the caterpillar itself. If we go to the book and we look up how many caterpillars a chickadee brings back to the nest every day, it's between 390 and 570 each day. And they rear their young, it typically takes between 16 and 18 days in the nest before the young fledge. So just getting the young to the point where they're going to leave the nest takes between 6,000 and 9,000 caterpillars. And then, of course, after they leave the nest, they continue to eat caterpillars. But we haven't looked at that. So 6,000 and 9,000 caterpillars. That's a lot of caterpillars. And these are tiny birds. A third of an ounce. I think that's four pennies. What if we were trying to provide enough caterpillars for red-bellied woodpeckers that are eight times bigger than a chickadee? And, of course, in our yards, in our viable food webs, we don't want just chickadees and red-bellied woodpeckers. We want titmice and we want, what is that? That's a bluejay. Bluejays and yellow throat warblers and bluebirds and indigo bunnies and prairie warblers and hummingbirds and all kinds of other creatures. Those are just the birds. There's lots of insectivores out there that need to be part of our food web. You want to talk about a specialized relationship, a lot people will look at a hummingbird and they say, well, there's one. They are specialists on nectar. But you know what 80% of a hummingbird's diet is? Insects. Believe it or not. So, yeah, they're specialists but it's not really on nectar. It's on insects. And that is not unusual. This is a list of the bird families in North America that rear their young on insects or the book will say other arthropods. The other arthropods are spiders that needed insects to become spiders. This is 96% of our birds are rearing their young on insects. And that's news to a lot of people because we always think of birds as seed and berry eaters. When we're landscaping for berries, we plant plants that make seeds and berries. And that's good because over the winter the birds that aren't migrating do need seeds and berries. But when they're making more birds, which happens to be a really important part in their life history, they need insects. So we need to plant the plants that are going to make those insects. No insects, no baby birds. What types of landscapes are going to accomplish this? Are able to produce the diversity and numbers of insects that we need? Well, in order to answer that question, we have to understand the specialized relationship between insects and plants. You have to remember that plants don't want to be eaten. Plants want to capture the energy from the sun, use is for their own growth and reproduction, so they have loaded their tissues with nasty tasting secondary metabolic compounds. A cocktail of chemical compounds that are bitter or down right toxic. And it's a wonderful defense. It keeps most of the insects of the world from eating most of the plants of the world. But we do know that insects eat plants. So how do they do that? How do they get around those chemical defenses? Well, you guessed it. They specialize. So the relationship between insects and plants are some of the most specialized relationships that we have in nature, and they're very, very common. 90% of the insects that eat plants can only develop on the plants with which they have specialized over evolutionary time. What they do is they pick a particular lineage, a lineage of insects will pick a lineage of plant and say I'm going to get good at getting around the chemical defenses of this particular plant. I'm going to develop the enzymes, the physiological mechanisms, the behavioral adaptions, the life history adaptations that allow me to eat this plant without dying. It takes a long exposure to that plant lineage for all these adaptations to fall into place. It doesn't happen over night. Here's an example. This is eastern red cedar. And it protects its tissues with beta --, which is a toxic --, and it's a very effective defense. Comparatively, there are very few insects that have adapted to eating eastern red cedar even though it's been here millions of years. But this is one that has. This is the Juniper Hairstreak. It is a specialist on eastern red cedar, which means it now has the enzymes and the behavioral adaptations that allow it to detoxify beta -- and eat red cedars without dying. And that is the upside of specialization. The downside of specialization is that now that's the only thing that this butterfly can eat. So if we take eastern red cedars out of our landscapes, the butterfly is not going to be able to all the sudden start eating oaks or grasses or lilacs or anything else, which means it has one option, and that is to disappear. If you're going to eat eastern red cedar, you might as well look like eastern red cedar. Everybody see the caterpillar there? Right here. There it is up close. The things that eat eastern red cedar are all extremely good at what we call crypsis. They blend in with the food that they're eating. It's another great advantage of being a specialist. I showed this picture to my wife and I said, do you see the caterpillar? And she said, of course. And I said, yeah, there it is right there. And she said, oh, no, I didn't see that one, I saw this one right here.

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Which I hadn't seen when I took the picture.

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Here we have two. We have this guy right here, but then we have a sphinx moth, which is a specialist on cedar, right there. There's his little horn out there. So yeah, check your cedar really carefully. There are insects on it. And sometimes they're mimicking the dead parts. This is the Juniper Geometer. Yes, Juniper Geometer right there looking like the dead tissues on cedar. So, yes, crypsis is fun. It's an advantage of being a specialist. So if we want to create landscapes that support viable food webs or species that are parts of those food webs, then we need to include the plants on which these species have specialized. And we can use this knowledge to just purposefully build the types of food webs that support particular creatures that eat insects. Let's use an example here. Let's use white-eyed vireo. My wife is very good at finding bird nests. She found this nest in our backyard last year, and she said, you should take pictures of these guys. I thought that was a good idea, so there we go. That's the white-eyed vireo rearing its young. And this allows us to see what it's rearing its young with. So in this case, it's bringing back this caterpillar right here. That happens to be a blinded sphinx which happens to be a specialist on black cherry. If I didn't have black cherry in my landscape, I would not have that blinded sphinx, and these babies would not have this meal. Here we have, obviously, you can see that is the chestnut schizura. It is eating viburnum dentatum. It's a specialist on viburnum dentatum. If I didn't have arrowwood, the native viburnum in our area, in our landscape, they wouldn't get that meal. And here, they're even more obvious. That's the drab prominent. It's a specialist on sycamore. So you get the picture here. If I didn't have sycamore, I wouldn't have the drab prominent. And they actually brought back a lot of drab prominents. So that became an important component of their diet. This is the eight-spotted forester moth. Native grapes. Got to have native grapes to have that bit of meal. This is the lunate zale, and it is another specialist on black cherry. So here we have black cherry contributing more than one species. Spicebush swallowtail, right here. Here's his little eye pretending he's a tree snake. Everybody thinks that protects him from bird. Well, not this time.

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I was surprised that they would be able to find this guy and bring it back, but there he is. So we need spicebush or we need sassafras. Those are the plants that support spicebush swallowtail. You get the picture here. This is the tufted bird-dropping moth, another specialist on black cherry. So now we have black cherry contributing three species to this diet. But these are hungry little birds. So they want a whole lot more than that. So we can build really complex food webs by including plants like black walnut. If we have black walnut, we can have the walnut sphinx. We can have the gray-edge boba loca. We can have the black-blotched schizura. Don't you love these names? Or the bride, we could have the bride. All those things are important components of the bird's diet. Native maples are going to produce plagodis inchworms or the green-striped mapleworm or the retarded dagger moth.

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Native elms will give us the four-horned sphinx, will give us the double-toothed prominent and many others. If we want to have deer in our yards, eh, never mind.

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Let's say we want fritillaries, then we need to keep our native violets around. All of our true fritillaries only eat violets. That's what the variegated fritillary larva looks like. Whoops, come back here. And you won't have them if you mow down all of those violets in the spring. They've got to be around. Remember, 90% of the insects that are eating plants are only going to develop on the plants with which they have co-evolved. There's no compromise here. They need what they need. So, if we want the hackberry emperor, of course we have to have hackberry. If we want cucullia asteroides, we have to have asters. If we want the brown-hooded owlet, then we need goldenrod. If we want the hog sphinx or the Pandorus sphinx or Abbot sphinx, then we need Virginia creeper. If we want the river birch dagger moth, guess what we need? River birch. I actually had to look that up.

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But there it was. Okay. Zebra swallowtail and the pawpaw sphinx are specialists on pawpaw. They will come to your yard if you put pawpaw in your yard. It happened at our place, and the nearest population was 26 miles away. And it took nine years, but they eventually found it and now have breeding populations of both. If you want the large paectes, you need sweetgum, and you'll get luna moth as well. The gray furcula needs native willows. The turbulent --, you can't tell which end is which, needs green briar. And variable oakleaf caterpillar and the redhumped oakworm and the southern oak dagger moth and the white-blotched heterocampa and the oblique heterocampa and the red-lined panopoda and the streak dagger moth and the laugher all want oak and so do hundreds of other species. Now, we can measure what happens when we take these native plant communities out of our landscapes, out of our gardens, and replace them with plants from someplace else. Here's a little experiment that we did. A student, I guess she was a junior doing her senior thesis at the University of Delaware, did this little study a few years ago. We went to hedgerows. This is a hedgerow in Maryland. We looked at hedgerows in Maryland, in southern Pennsylvania, and northeast Maryland that were invaded with non-native species. So here we have autumn olive, genus elaeagnus. Everybody calls it ugly Agnus, and I like that name. All that silver leaf material there is ugly Agnus, but we also have multiflora rose and oriental bittersweet and porcelain berry and Japanese honeysuckle and bush honeysuckle and Japanese knotweed and Norway maple and Bradford pear and barberry and privet and all the things that have escaped from our garden. That's what those hedgerows are made up with. And we measured the caterpillars in those invaded hedgerows compared to hedgerows that were largely native plants. Very few invasive species there. And this is what she found. Five times more species of caterpillars in the native habitats, the uninvaded habitats, and 22 times more caterpillars themselves. Which means the plants from Asia are very poor at supporting the caterpillars from that part of the mid-Atlantic states. So that's obvious. The question is, does that matter? Does it matter? It matters if you eat caterpillars. Like this common yellow throat is doing. This poor guy is trying to feed his offspring down here, and if he's in a habitat that has been overrun with these non-native species, he's going to have 22 times fewer caterpillars to forage on, to find. And you might say, well, he can just forage 22 times harder to get the same amount of food, but he really can't because he's already foraging all day long. 156 trips a day. One trip every five minutes. And believe me, he's going to need 6,000 caterpillars too. So to ask him to do that 22 times harder is not biologically realistic. And the prediction is that when you have these habitats that are overrun, and in your case it would be buckthorn and bush honeysuckle and all the other things you have, you're going to have 22 times less bird biomass because you've reduced the food load that much. What happens if we just focus on exotic ornamentals that we put in our yards? So they may not be invasive species, although 85% of our woody invasives have come from the exotic ornamentals that we put in our yards, but even if your plant is not invasive, something like crape myrtle. I guess you don't do that up here. It's not an invasive plant, but it's not, well let's see how it's doing. If we go to Michael Dirr's manual for woody landscape plants, he recommends that we landscape with 69 genera of plants from someplace else, typically Asia. And we look up the number of caterpillar species that can make a living on those particular plant genera, it's an average of about four species. Compared to the native ornamentals that Michael Dirr recommends, and that is 101 species he recommends. They, on average, only support 72 species of caterpillars. So when we landscape with these non-native plants, and we all know that we're doing that, there's a tremendous loss of caterpillar diversity and biomass, which means the food these birds are using or trying to use has disappeared the way we landscape. So what is happening to these insectivores relying on all of the insects that our plants make up? I could give you nasty statistics all day long, but that gets really depressing. I have learned people have a limit of depressing news. You hit that limit and everybody turns off and that's the end. So I'll just give you one depressing statistic, and this is what's happening to our neotropical migrants, the birds that breed in North America then move to Central and South America to reproduce, I mean to spend the winter. 127 species of neotropical migrants are in steep decline. We now have 50% fewer birds of all types compared to just 40 years ago. And we know this from breeding bird surveys that have been going on since 1966 and also banding stations all over the country that are actually measuring abundance as birds migrate. And it's not just the birds that need insects. We know what's happening to our birds because people like birds, but all the other things that nobody's monitoring, what's happening to them? So, for example, spiders. I mentioned spiders eat insects because they do. All spiders eat insects or they eat other spiders that eat insects. There's a tremendous diversity of insect predators out there. This is a baby assassin bug here having a treehopper for a meal. If we took away the treehopper and all the other insect herbivores, we would lose those insect predators, and they're part of food webs as well. Our frogs eat insects. Our toads eat insects. All of our amphibians are eating insects. And even our freshwater fish depend on insects. They do depend on insects that live in the streams themselves, but they depend largely, 60% of their protein comes from terrestrial insects that fall into our lakes and our streams. So if your stream is lined with Japanese knotweed, nothing is falling into it, and I wonder what happens to Mr. Fish here. Our lizards eat insects, our bats eat insects, and even our rodents eat insects. We always think of rodents as seed eaters because they do eat seeds when they can't find enough insects, typically the wintertime. Why is everybody eating insects? Because they're really good food. Pound for pound there's twice as much protein in insect meat as there is in beef, and insects have organs in their abdomen called fat bodies that are loaded with lipids, high energy compounds that allow these little guys to grow quickly and reproduce quickly, which, if you're a mouse, you want to do because there's a lot of things that want to eat you. But it's the same reason larger organisms are eating insects. The skunk is digging up your yard to get the grubs that are in your yard. Possums eat of lot of insects. And even things we don't think of as insectivores are eating a lot of insects, like a red fox. What do you think the percentage of a red fox diet is that is comprised of insects? 25%. 25%. That happens to be a lot. That's a quarter. That's a lot. 23% of a black bear's diet is insects. And even things that don't eat insects regularly need insects. This is sharp-shinned hawk, and even though I have a picture of it with a dragonfly in its talons, it's really a bird predator. It eats other birds. So you might think, well, we can have sharp-shinned hawks even if we take insects out of our neighborhood food webs, but no you can't because the birds it's eating needed insects to become birds. And, of course, we already talked about those birds. Those birds are relying heavily on insects when they are reproducing. So a world without insects really is a world without biological diversity. And, unfortunately, that's what we're creating these days. I don't know if you've heard the term novel ecosystems. There's a lot of ecologists talking about novel ecosystems. As a matter of fact, they say that three-quarters of wild Earth, three-quarters of all the ecosystems on Earth now are considered novel. What does that mean? It means that we have moved plants and animals around so much that these ecosystems are now compromised of plants, largely, that did not co-evolve with each other. They've never seen each other before in evolutionary time, and they certainly did not co-evolve with the local animals. So they've had no time to develop all the specialized relationships that I was talking about earlier in the talk. And those are the relationships that really are nature. So you've got this hodgepodge of plants from all over the world, and there are people that are trying hard to tell use that, hey, that's pretty good. They're doing a good job. None of them have measured food webs, though. And we know what's going to happen when you take away the specialized relationships between insects and these plants. Those food webs are going to collapse. Okay, if those food webs are collapsing and the birds are disappearing and all those things, we might want to ask the

question

how many species do we need before it starts to affect ecosystem function? That's a good question. And remember, when I'm talking about species disappearing, I am not talking about global extinction. I am talking about local extinction because ecosystems function locally. So picture your neighborhood. That is or was a functioning ecosystem. And if you look at the number of species in that neighborhood now and compare it to what was there before the neighborhood was built, I'll bet you have fewer than you used to.

And the question is

what has that done to the function of your local ecosystem? Whether or not those species are globally extinct. Well, back in 1955, Robert MacArthur, a very famous early ecologist, created this hypothesis. He called it the law of nature, and he said as we increase the number of species in an ecosystem, ecosystem function goes up, and he drew this line and it looked pretty good. And if you call it the law of nature, it sounds like that's really what's going on. But in 1955 it's hard to test these things. It's hard to actually do long-term experiments, look at the number of species, and then measure some kind of ecosystem function. So it really went untested for a long time. Back in 1981 this was another hypothesis that was advanced by Anne and Paul Ehrlich. They called it the rivet hypothesis. You've probably heard about it. And they said as we add species to an ecosystem, ecosystem function will go up to a point, but then it levels off and all of these species are redundant. And they liken the species in an ecosystem to the rivets on an airplane. They say we've got more rivets than we need to hold that airplane together, so if one pops, the airplane doesn't fall apart. The wing doesn't fall off. But if you keep popping rivets or you keep losing species, you do get to a point where the wing falls off and the ecosystem starts to crash. Where that point is, who knows. But it was introducing the concept that we have redundancy out there. We really can lose species and it'll be okay. And that made a lot of people feel pretty good because we were losing species. But it didn't seem like it was going to be a disaster. Well, people have started to test this. Three papers came out just in 2012. Three different sets of researchers looking at what the relationship really looked like, and it turns out Robert MacArthur was right, that as you add species to an ecosystem, ecosystem function goes up. But that also means as you take species away from an ecosystem, ecosystem function goes down. So how many species do we need in our ecosystems? We need all of them because we need as much ecosystem function as we can get because as a species it is biodiversity that creates the ecosystem services that support humans. And this happens to be important. Most people don't think about this every day. They think that you get your water from the tap and you get your food from the store and you get your oxygen from the air because it's always been there, but those are all ecosystem services produced by functioning ecosystems, and if they disappear, we're going to notice that. If you have a diverse ecosystem, it is more stable so it returns to its original productivity if it's disturb much faster when it's diverse. It's better at producing biogeochemical processes. Things like sequestering carbon, cycling nutrients. Those are vital and important processes. It increases ecosystem productivity. What does that mean? Well, let's be selfish about it and think about productivity in terms of the services we humans need, ecosystem services. When you have a productive ecosystem, you get more ecosystem services, and that's good. If you have a diverse ecosystem, then it's less susceptible to invasion from all these organisms from someplace else. Those are all good things. There was a huge study in 2005 called the millennial ecosystem assessment that was conducted by hundreds of scientists around the world. It was a global effort, and the goal was to determine the degree to which the planet can still produce ecosystem services. And, unfortunately, the results were not encouraging. They said, in a 900-page tome, that 60% of the Earth's ability to make ecosystem services have been compromised. We have degraded our ecosystem service production by that much. And that is very bad news because every time we add somebody to the planet, we need more ecosystem services. And we're doing that about three times a second, by the way. Unfortunately, every time we add somebody to the planet, we are getting fewer ecosystem services because of a very unhealthy relationship between humans and nature, and that's what I will talk about in the next talk. So this is something we have to turn around as fast as possible. We can't keep losing ecosystem services without nasty things happening. What's an ecosystem service? This is something we all take for granted every minute of every day. Things like the production of oxygen. As I said, we all think oxygen has always been here. Plants make oxygen, but you know what? Before there were plants on the planet, there was no oxygen. If we take all the plants away, there will be no oxygen. Are we taking all the plants away? Well, nobody's thinking about that. Everybody says of course not. That can't happen. That can't happen. But we've already taken away half of the forests on the planet. Flying out here, I read a Science article, they now have much better ways of measuring, through satellites, the amount of forest cover we have, what we've added, and what we've taken away. Last year, we took away, I think it was 1.2 million kilometers of forest. So we're still whittling away at it awfully quickly. And somebody's going to say, well, we get our oxygen from the algae in the ocean. We do. 51% of our oxygen comes from the algae in the ocean. But look what we're doing to our oceans. Either way, we've got to keep plants around. Not just because they make oxygen but because they provide most of the vital ecosystem services that keep us happy and healthy. When water falls from the sky in the form of rain, it hits the ground and it wants to run to the ocean. If there were no plants on the ground, it would get there pretty fast. There'd be nothing to encourage it to infiltrate. But the plants hold it on the land surface, allow it to infiltrate so we can use it in the form of aquifers, and it also cleans our water. So it's producing clean water and storing it for us for free. Important ecosystem services. It's plants that help build topsoil, and the most important thing they do is hold it in place. Again, if you had no plants on the land surface, you'd have no topsoil. That would have washed away a long time ago. And we need topsoil. It's plants that prevent floods. That's an important one. But we got to keep the plants in the ecosystems for that to happen. As a matter of fact, it's plants that are buffering us from extreme weather events if we keep our ecosystems well vegetated. You don't have events that look like that when you keep the plants in place, or if you do, they are quite rare. And, of course, it's plants that sequester carbon. This is a Ceiba tree in the forest of Costa Rica. It is 600 years old. It is built out of carbon that has pulled out of the atmosphere and has locked up in its tissues. That is 18 people standing at the base there. So it's a big one. The only reason the Costa Ricans did not cut it down is because it was too big. They couldn't do it, so they left it. We should be putting plants like this on the planet as fast as possible. I'm not saying trees are a permanent solution to our carbon woes, but I will take a 600-year solution any day. A third of the carbon that is in our atmosphere right now has come from, not from the fossil fuels, two-thirds come from the fossil fuels, but a third has come from the trees that we have cut down already. And, of course, all that carbon is released into the atmosphere. We're still deforesting the planet at a rate of 50,000 acres a day. So we can do much better in this regard. What are animals doing for us? They're recycling our garbage. That's good because we make a lot of garbage. They're dispersing the seeds of those plants. This is one people don't think about very much. But if these acorns just sat underneath the parent tree and were not dispersed someplace else, unless that tree fell over and died, none of them would make it to maturity. So getting the seeds away from the parent is really important, and it's animals that are doing that for the most part. Animals are providing free pest control services. Another service we don't think about, but they're doing that all the time. And, of course, animals are pollinating our plants. 80% of all plants and 90% of our angiosperms, the flowering plants, are pollinated by animals, not by the wind. If we lose these pollinators, we will lose 80% to 90% of our plants. That's just not an option. It's not an option. And we're starting to talk about this, but we need to do a lot more than talk. We need to preserve these guys in a great amount of diversity. Also, increasing evidence that we need to interact with nature, particularly when we're young, for healthy mental development. And this message is coming from Richard Louv, who wrote Last Child in the Woods, and coined the term nature deficit disorder. He says our kids are not out playing in nature anymore. At the same time, they're suffering from elevated levels of ADHD and childhood obesity and childhood depression. He says maybe there's a connection between the two. Let's do some research, see if there's a connection. Okay, that's a good idea. What are our kids doing? >>

INAUDIBLE

And the question is

>> Yeah. Whatever it is, it's electronic, which means they are inside. Richard Louv also said that our kids are the future stewards of the planet. And we don't have to do research to prove that that is true. And, of course, if they're the future stewards of the planet and they have no emotional relationship with the things they're supposed to be stewarding, they're going to be lousy stewards. So Richard Louv says get the kids out of the house, let them run out in the backyard, turn over the rock, and play with the salamander. And I couldn't agree more. I can show you that picture because that's my granddaughter.

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And the question is

And that's my wife. We have to get the kids out of the house. Let them run out in the backyard, turn over the rock, if there is a rock, but these days we have sterilized our neighborhoods to the point where nature is gone and there will be no salamander under that rock. Now, why don't we let our natural areas make all those ecosystem services we need? Protect all the biodiversity that we need them to protect? I will expand on this in the next talk, but the simple answer is we don't have enough natural areas anymore. This is what our light map looks like in the US. So we're pretty much everywhere. A lot of this dark area here, we've got the Rocky Mountains and some nice places left, but only 5% of the US is relatively pristine. The rest is, this is all cows here and this is corn and soybeans and this is people. That's what it looks like. We've taken 950 million acres of virgin forest east of the Mississippi. We were an agrarian society when we came here, so we chopped it all down. But then we did start to move into cities and suburbs, and many of those forests grew back in what we now call secondary structure, secondary growth. But we haven't stopped growing. We're still adding 5,700 people to the US every day, and those people need a place to live and something to eat so we're sprawling. And when I fly home, if it's not snowing, I'll look out and this is what I see. I see little habitat patches. Little habitat fragments. And that's the question. Can these habitat fragments maintain the diversity, biodiversity, and the ecosystem services that we absolutely need? Four million miles of paved roads out there. The surface area of those paved roads is equal to five times the size of New Jersey. If pavement was a functioning ecosystem, that'd be okay, but it's not. And, of course, we have a love affair with lawn. 45.6 million acres of lawn. That's actually, yeah, there you go, 72,000 square miles of lawn. We're adding 500 square miles of lawn to the US every year. And it's all dedicated to this status symbol which looks nice, but it is not diverse, it is not a functioning ecosystem. So we've usurped so much of the natural world that we now need to build these functioning ecosystems right at home, right where we live, and right where we work. Let's focus on those areas before we start focusing on agriculture. We do need to dedicate a lot of land to producing the food we need. So, how are we doing in terms of making functioning landscapes at home? We have looked at 66 houses from 22 developments in the southeast Pennsylvania and northeast Delaware and Maryland area and measured everything we could about the landscapes. This is what it looks like. 92% of the area that could be landscaped is lawn. So you're talking about barren landscapes. Out of the plants that are there, 74% of the species are from someplace else. They are non-native. 79% of the individual plants, so let's just say 80% of the plants that are in these barren landscapes are not contributing to our local food webs, they are not helping my chickadees out, and 9% of those plants are highly invasive. Not because they have invaded these properties but because the homeowner has planted them. Things like Bradford pear and things like miscanthus and burning bush and barberry and all of those guys. So we have barren landscapes that we have built with plants largely from China. We've also measured the amount of tree biomass. Now this is in the east where you're supposed to have a forest really. Only 10% of the tree biomass that could be in our suburban developments remains compared to nearby wood lots. And we are comfortable living in spaces where we have thrown 90% of the trees out the window. Which is why when we look out the window, we typically see nothing. And we are so used to seeing nothing, we think that's normal and we have labeled that good land stewardship, and now in so many places if you landscape in a way where you actually see something alive and moving, you're fined by your local civic association. So we have a ways to go. I'm trying to convince people to think about their yards, their landscapes, as an opportunity to produce the ecosystem services that they need. I presume there's a family that lives in that house, and if they don't produce all the ecosystem services they need at home, they're going to have to borrow them from someplace else. They're not going to borrow them from their neighbor because his yard looks just the same. They're not going to borrow them from the open space of the township because that's almost certainly a soccer field or a golf course or some giant expansive lawn where people walk on a cement path in a circle. So let's do it at home. We used to borrow it from nature, but, as I said, there's just not enough nature anymore to support our populations and our tremendous demand for ecosystem services. So if we want to make clean water at home, we don't want 92% lawn because lawn makes dirty water, at least the way we treat it. We put on our fertilizers which contain pesticides and then it rains and they all run off into our watersheds. And it doesn't encourage infiltration. If we want to sequester carbon, we don't want just 10% of the trees that could be sequestering the carbon and we don't want to use short-lived ornamental trees like Bradford pear that will grow for 30 years and then fall over in an ice storm and release all the carbon they have just sequestered. We need long-lived trees like oaks, hickories, things like that that will keep that carbon in our landscapes for hundreds of years. Again, not permanent solution but it will slow the release of carbon into the atmosphere, pull a lot of it out, and give us time to deal with all the fossil fuels we're putting out there. If we want to rebuild viable food webs in our yards, again we can't be focusing on plants from outside of our local food web. A lot of people say, what is a native plant? It's a plant that is from outside of your local food web, and it does not co-evolve with the things that need to use it. By the way, that's my neighbor's house.

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And the question is

And he has 10 acres. Most of it's lawn. You can't see that. But 100% of the plants in my neighbor's yard are from someplace else. So it's a 100% alien landscape. And the question is, how do we get there? Why did my neighbor do that? He doesn't know anything about plants. He just hired a landscaper and that's what he got. We got here because we have come to see plants as decorations. Why? Because they are beautiful. They are beautiful decorations so we're going to decorate the landscapes with them, which means we go all over the world to find the most beautiful plants, and if they don't aesthetic value, if they can't be pretty or a screen or a focal point or something, we don't use them. Which means we have ignored all of the important ecosystem functions that these plants are providing. I think we can balance that. Looking at criteria for the selection of plants, we can still look for beautiful plants, but we also need to look at what they're doing. What is their food web? I think that plants have so many important ecosystem services, but I think this is the most important one because this supports all the rest of the life that's out there. If you have no food web value, you've got a dead landscape. So let's consider the ecological value of plants as well as their aesthetic value, and then we can have balance in our landscapes. What does a biodiversity friendly neighborhood look like? This is the most important thing that we need to do. We need to build biological corridors that connect the isolated habitat fragments that we have out there, and again I'll expand on this in the next talk and tell you why that is so important. But where are these corridors going to be? They're going to be in our neighborhoods. That's what's in between our isolated habitats that exist. So where are we going to build them if we put them in our neighborhoods? I think we ought to reduce the area that's now in lawn. I'm going to need 45.6 million acres of status symbol. Let's pick another status symbol. And, of course, we need to build those corridors out of the plants so they're going to support the food webs, those specialized relationships that I was talking about. How are we going to do that? Let's flip-flop the landscaping paradigm we have followed forever. We have built our house and we put the flower bed typically right next to the house in there, a few trees, and then were exhausted. No more landscaping. So everything by default becomes lawn. Let's turn that on its head. Let's build the house and now figure out where we want lawn. Where do we want turf grass? Turf grass really is a good plant if you're going to walk in that area. You can walk on it without killing it. So let's figure out where we're going to walk in our landscape. Let's use grass to guide us through our landscape so that we can actually interact with something outside. I look at where my neighbors walk on their 10 acres. Nowhere. Never outside.

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And the question is

But let's say you want to get married in the front yard. You need some lawn there if you want to walk to the backyard. Nice grass path. Throw a Frisbee here, have a barbeque. Wherever you're going to use that yard in a productive way, that's where the lawn goes, and then everything else by default becomes heavily planted. How many landscape designers do we have here? Good. The ball is in your court. How do we get that many plants into our landscapes without them looking messy? Because we all know our culture doesn't like messy. We can do that. We know how to do that. Go to any arboretum and they are filled with plants and they're not messy. So we can have well tended, manicured landscapes that are loaded with productive plants. And if we do that, if we convince our neighbors to do that, look, now we've got that connectivity that I was talking about. Connecting with the wood lot over here and the wood lot over here, we can still get to mow our lawns. But now we're living in a living landscape instead of a dead one. And if we do this in half the area that we now have in lawn, let's make the math simple. Say we've got 40 million acres in lawn, we can create a new national park that will be 20 million acres in size. How big is that? Well, we're going to do it at home so we can call it Homegrown National Park. That's bigger than the Adirondacks plus Yellowstone plus Yosemite plus Grand Tetons, Canyonlands, Mount Rainier, North Cascades, the Badlands National Park, Olympic National Park, Sequoia National Park, the Grand Canyon, plus Denali, which is huge, plus the Great Smokey Mountains. You add up all those parts, it is still less than 20 million acres. We are going to create the largest national park in the US. Let's take areas that look like this and turn them into that. Let's take this lovely design here.

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And the question is

It's a mulch garden.

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And the question is

And turn it into a living landscape that also has aesthetic value. Here we have a lovely corporate landscape that invites the employees out at lunchtime to get sunburned.

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And the question is

It could be a beautiful landscape that looks like this. And you'd think, oh, it takes 500 years to build that. It doesn't. It doesn't. It can happen relatively quickly, and there is research, increasing amounts of research that shows if we spend just 15 minutes in a landscape like this, our blood pressure drops, our cortisol, the stress hormone in our blood drops, our cancer is cured, we don't get divorced anymore, and we win the lottery.

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And the question is

If you want to look at a review of all the literature supporting this, as of two years ago, this is Richard Louv's second book about nature called The Nature Principle. And it's a very active area of research showing how valuable these plants are simply from a medical perspective. Does that mean your landscape has to be 100% native? No, it doesn't. Just understand what the plants that are not native are contributing to your landscape versus what they are not contributing. So, again, let me pick crepe myrtle out again because it's used so much over the US. It's a beautiful plant, beautiful bloom, and contributes just about zero to our food webs. So you've got a beautiful structure there that is biologically inert. What does that remind you of? It reminds me of a statue. So let's consider the crepe myrtle a statue in your yard.

The question becomes

how many statues...

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The question becomes

Do you really want? So, are all native plants equally good at supporting the food webs we're trying to rebuild here? Now, this becomes an important question, and the answer is a surprise to us. No, they're not. So being native is a great first step, but there are some really good natives and there are some ones that are not supporting much at all. This is a list of a the, it's a ranking of all the woody plant genera in the mid-Atlantic states. If you go to my website BringingNatureHome.net, you get a similar ranking of all the herbaceous plants in terms of their ability to support caterpillars, the primary food of our breeding birds. That's what the little numbers after each plant genus are. So memorize that.

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The question becomes

By the way, this is the mid-Atlantic states, and you're going to say, we're not the mid-Atlantic states. That is true, which is why the Forest Service has funded us this year to create a list like this for every state in the Union. And they want it by the end of the year.

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The question becomes

My technician, Kimberly, is working on this so you clap for her if she does it. But that will be great. And they want it by county. So you can look and you can see what the most productive plants in your county are. So I hope she can do that. In the meantime, this is what we have. And what you will find is that oaks are number one, number one genus. 557 species of caterpillars supported by oaks compared to ginkgo I don't know if you guys landscape with ginkgo. They certainly do in the east. Four species are recorded on ginkgo I have never found any of them. I have never seen a ginkgo leaf with any bite marks on it. So it's an extremely unproductive plant. Prunus, native prunus, things like black cherry, support 456 species of caterpillars. It's number two on the list. Very productive compared to something like zelkova which looks a lot like elm and that's why it was brought in when all the native elms died from Dutch elm disease. What you can't see there is that it supports zero, zero caterpillars on zelkova. One of our favorite foundation plants is Pieris japonica. Two species recorded on Pieris compared to one of our native viburnums, 103 species. So there is a tremendous difference in the productivity of these productive native plants versus the traditional exotic ornamentals that we use in our yards. So why do we need native plants in our gardens? A number of reasons have been suggested. Some of them directed at me.

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The question becomes

A lot of people say we want natives because it gives us a sense of place, and if you appreciate a sense of place, if you want to know what your biological heritage is, that's great, but unfortunately most people don't. They don't care about that. So saying you need a sense of place isn't going to convince anybody to do anything. We don't need natives in our gardens because they're prettier. We have beautiful native plants but there are beautiful plants from all over the world too. So it's a really tough argument to make saying natives are prettier. It's not because we're nostalgic Now we're getting to the things that I've been accused of. I'll say I just want to do this because I want it to be like it used to be. And people say, oh, everything changes and get used to it and blah, blah, blah. It's not because of that. And it's not because we oppose change. I don't oppose change. Change is normal. Unrealistically quick or fast biological change is not normal. But it's not because of that. And it's not because I dislike foreigners.

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The question becomes

That's called nativism. It's none of those. We need native plants in our yards because we need functioning ecosystems. So if we rebuild these ecosystems, will they be exactly like what used to be there before we came? No. We have changed too many things for that. Can they be functional and support life? Yes, they can. And we're not going to get this ecosystem function without the species that interact with each other. So, we can save nature if we embrace the specialized relationships that are nature. And, as I've said several times, they always start with native plants. Thank you very much.

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