Nature’s Best Hope: An Interview with Doug Tallamy
“There can be no purpose more inspiring than to begin the age of restoration, reweaving the wondrous diversity of life that still surrounds us.”
Photo Courtesy of University of Delaware
Doug Tallamy is the inspiration and moving force behind Homegrown National Park, the effort to educate people about the things they can do in their own backyards to save biodiversity. Dr. Tallamy is based in Pennsylvania and teaches at the University of Delaware, but he has strong connections in New England. In my conversations with Doug, and in all that he does, his message remains the same: We are in a biodiversity crisis, and we are all responsible for solving it. Homegrown National Park is his strategy for helping everyone assume that responsibility. From the website:
“Our National Parks, no matter how grand in scale, are too small and separated from one another to preserve species to the levels needed. Thus arose the concept for Homegrown National Park—a bottom-up call-to-action to restore habitat where we live and work, and to a lesser extent where we farm and graze, extending national parks to our yards and communities.”
Doug has given many talks to many different groups about Nature’s Best Hope. This talk, hosted by the Cary Institute of Ecosystem Studies, is especially engaging, and is illustrated with beautiful photos of some of the organisms he speaks of in our interview.
“We are in a biodiversity crisis, and we are all responsible for solving it.”
Liz Thompson (LT): I’d like to talk about a variety of things: about the biggest threats to our world; about what conservation is to you; about biodiversity on farms, in gardens, and in backyards; and about forest management. Oh, and how we are going to save the world.
Doug Tallamy (DT): Here’s the overview that unites everything you just said into one common goal. We’ve got a biodiversity crisis. We don’t have to go into that again, except to say it’s real. It’s getting worse. About saving the world? The world’s going to be fine. It’s humans and everything else in the world that’s in trouble because we are not sharing our spaces. We just keep growing, taking more and more space. We’ve got the idea that humans and nature can’t coexist. We’re going to have to toss that idea and learn how to coexist—how to have functional ecosystems in human-dominated landscapes so that nature can thrive where there are a lot of humans. That’s the new goal.
“we are not sharing our spaces. We just keep growing, taking more and more space.”
We do have parks. We do have preserves. But everything in between those parks and preserves is private property. And those are the areas we have to make into viable habitats, because the parks and preserves are too small and too isolated, and there’s a steady drain of species from them.
So, we’re going to fill in the blanks. And that means we’re going to fill in the blanks on farmland, on residential landscapes, in urban centers—everywhere!
That’s what unites everybody. We all have the same goal. How to learn to do what we’re doing and support natural systems at the same time.
Let’s talk about farming at different scales. We have 410,000,000 acres of cropland in this country, and 770,000,000 acres of rangeland. That’s the bulk of the agriculture right there. And people think there’s nothing you can do to cropland to make it more friendly to biodiversity. That is so untrue! We have taken the cropland, starting in the Midwest, and it comes all the way east—everywhere in this country—and gotten rid of the “weeds” on the sides of the fields. Those were milkweed, aster, and goldenrod, all the things that supported healthy monarch populations and healthy native bee populations. They’re gone, and now it’s all lawn.
Milkweeds of all species, including this common milkweed seen throughout New England, are essential to the completion of the life cycle of monarch butterflies. Photo © Liz Thompson
So not only have we gotten rid of viable habitat on thousands and thousands of miles of verge on the side of the agricultural land, we’ve turned it into a carbon-producing status symbol. So, get rid of the lawns, put the native plants back on the edge of agriculture. Doing this is not a threat. It doesn’t reduce yield a bit. It actually saves the farmer money because he doesn’t have to mow anymore. It helps climate change by sequestering carbon. It helps manage the watershed, and it can contain a lot of biodiversity, including the monarch. Tidying up farm edges is the single thing that has decimated milkweed populations from Canada all the way down to Texas.
Then there’s the fairly new concept of prairie strips. Right in the middle of your corn and your soybeans. There is excellent research on this in Iowa, and it’s just a great idea. So, you’re putting a prairie strip right in the middle of your farmland, perpendicular to the flow of water off the land, which means it intercepts topsoil when you have a storm, and reduces topsoil loss by something like 95 percent, along with a 92 percent reduction in pollutants, also intercepted by the prairie strip. So, the excess nitrogen and phosphorus and all the stuff that we load the Mississippi with. And of course it’s supplying pollinator habitat.
And it’s supported by CRP [Conservation Reserve Program]. So, the farmer isn’t losing any money—they’re paid to do that, as they should be. It’s a valuable ecosystem service for everybody, and the farmers shouldn’t have to foot that bill. We all should be supporting that. So put the “weeds” back on the side of the road. But don’t call them weeds, call them native plants!
The other thing is to stop the totally unnecessary use of neonicotinoid seed coatings, which do not increase yield at all. [Read about a recent conference on neonicotinoids.] Ninety-five percent of that material washes off the seeds into the watershed, where it is very persistent. Or it blows away on dust (and nobody’s looked at what’s going on there). But we do know we have gotten drastic reductions in grasshoppers and other species as a result of neonicotinoid use. It’s totally unnecessary. Neonics are 7,000 times more toxic to insects than DDT was. It’s not trivial. And as a seed coating, it’s not even counted as an insecticide, so it’s not in any governmental statistics about the amount of insecticide we’re putting in the land. Yet it’s on every seed you buy.
LT: Thinking about small farms and home gardens, are there crop plants that are worse for biodiversity? Or can we assume that most crop plants are not helpful for biodiversity because they’re mostly not native? Are there any distinctions you can make?
DT: Agriculture is designed to feed us. It’s not designed to support biodiversity. We are using the plants that are best at producing the food that we need. So, it’s going to be very difficult to say, “We’re only going to eat plants that support a lot of biodiversity.” That’s just not going to happen. We do have some permaculture plants that may be native—persimmons, pawpaws, walnuts—but it’s trivial compared to what we really eat. We eat corn and wheat. And soybeans. That’s what we live on.
LT: What can people do in very tiny spaces to support biodiversity, for example a tiny garden in Manhattan?
DT: In a flower pot you can grow a flowering native plant that supports pollinators. You can put Joe-pye weed in a container and it’s a wonderful butterfly plant. The fall asters that people put in containers are beautiful, and they are perfect for migrating monarchs. This is because a lot of the plants, including many of the goldenrod species, have stopped blooming before the monarchs finish their migration. They need forage the whole way down, particularly here in the northern part of their range. We get monarchs moving through here in early November, and by then there’s very little for them to eat. So the fall blooming asters are really important. And anybody in Manhattan with any small outdoor space can grow those. Picture an apartment complex where people do have balconies. It’s a pile of bricks with no biodiversity value at all unless you put a whole bunch of container plants on the porches, on the balconies. Then it becomes a rock outcrop with plants all over it, and those plants are used by pollinators—by honeybees, yes, but by the native bees as well.
“In a flower pot you can grow a flowering native plant that supports pollinators. You can put Joe-pye weed in a container and it’s a wonderful butterfly plant. The fall asters that people put in containers are beautiful, and they are perfect for migrating monarchs. This is because a lot of the plants, including many of the goldenrod species, have stopped blooming before the monarchs finish their migration.”
As they make their way south in the fall, monarch butterflies rely for nutrition on late-season flowers like New England aster. Photo © Liz Thompson
Look at the number of bees that have been recorded in the High Line public park, where native plant gardens have been established. As of 2019, 33 bee species had been recorded, accounting for about half the total species recorded in all of Manhattan. These bees are around and will use forage whenever it’s available. So, the idea that “I live in the city, I can’t support biodiversity, and I don’t have the responsibility to do so … ”—we’ve got to get rid of that. Everybody’s got the responsibility because everybody requires biodiversity. Eighty percent of us live in urban centers. They’re not the best places to garden for biodiversity, but they’re not zero contributors. We can do a whole lot better. And the idea that only plants from China will grow in a city is just nonsense. We’ve had the idea that our native plants can’t handle the rigorous city conditions. Find ones that can! We’ve got native plants that are good at doing a lot of things. But we haven’t looked because we’ve always had the ginkgoes and other things from China. We can do much better that way as well.
Tri-colored bumblebee is one of many native bees that feed on the nectar of Joe-pye weed. Photo © Kent McFarland
LT: Speaking of ginkgo, I’ve heard you talk about three categories of plants related to biodiversity. Can you talk more about them?
DT: You’re talking about contributors, non-contributors, and detractors.
LT: And ginkgo is a non-contributor, is that right?
DT: It’s a non-contributor. It’s not invasive, it’s not moving around—it’s just there. And nothing eats a ginkgo, which means it’s contributing no energy to local food webs. So, in terms of the major benefits of plants, they do several things, but making all the food that supports animal life on the planet is a pretty important benefit. And our non-native plants are far poorer at doing that than the native plants. As I said, nothing eats a ginkgo leaf. Which means it’s not contributing energy to the local food web. If it’s just there, then I call it a “statue.” And when we plant statues like ginkgo or crepe myrtle, an ornamental overused throughout the south, that’s an issue.
LT: You have a chapter in your book: “Are Alien Plants Bad?” You are talking about the detractors, correct?
DT: The detractors are the invasive ones. They are the ornamentals that have escaped cultivation and spread throughout our natural areas. Ginkgo doesn’t do that. But burning bush does, and multiflora rose, and Bradford pear, and on and on.
LT: Is the problem that they’re just taking up space from the ones that do support the food web?
DT: Yes. They are occupying the space that the productive native plants used to occupy. And it wasn’t long ago that we said, “They’re just superior plants that are far more competitive.” They’re not! The reason they’re taking up that space is because the deer don’t eat them. Deer eat all the natives; they leave the non-natives, and of course that’s what we have left: non-natives. The barberry, the burning bush. And we say, “What great plants!” No, it’s just that the deer don’t like them any more than the insects do. So, it’s the interaction—between overabundant deer and these non-native ornamentals that have escaped—that has created the terrible invasive species problem in our forests.
“it’s the interaction—between overabundant deer and these non-native ornamentals that have escaped—that has created the terrible invasive species problem in our forests.”
LT: Tell me more about overabundant deer.
DT: In parts of Pennsylvania, for example, the deer population is 10–14 times above the carrying capacity. And it’s devastating our forests. There’s no forest recruitment. It encourages those invasives. You’ve got a browse line with Japanese stilt grass, and that’s your forest understory at this point. You do that for 50 or 75 years and you’ve got no forest left because the trees get old, they fall down, and all you get is invasive vines taking over after that.
LT: This gets to the topic of helping people to care. In one of your talks, I heard you quote a student who said, “We’re not managing nature, we’re managing humans.”
DT: Amanda Crandall said that.
LT: Amanda Crandall! Speaking of managing people, hunting is a revered traditional activity here in Vermont, and in much of New England. It’s part of our culture. And many hunters don’t think there are enough deer, and they say so in public meetings. Which leads to the question, how do you instill an understanding of this problem, and more broadly an appreciation for biodiversity, in young people, who will ultimately become the “people managers”?
DT: If we don’t get a handle on this, life will not continue forever. That’s the message nobody seems to internalize. You get ecosystem collapse. It’s happening all over Africa, and then we call it social unrest. You have people killing each other because there’s nothing else to do. For example, the Civil War in Syria: It’s old business now but a terrible thing. There were three drought years in a row. Farms collapsed and the farmers moved to the cities, and that is what caused the social unrest. So, it was directly caused by the environment, but nobody sees it that way.
Back to the deer problem. “There’s not enough deer.” I’ve heard all these arguments. Someone did a study in Pennsylvania where they put geolocators on hunters. They agreed to wear them so the researchers could track where they went. The research found a typical pattern: a hunter pulls up to their favorite hunting place, gets out of their car, and walks about 10 feet. If there’s not a deer there, there’s not enough deer, and they drive to another location. They will not walk the mile down into the valley where the deer actually are. There’s plenty of deer.
No hunters are hunting in suburbia. I regularly see 14 deer in my yard. We have 140 deer per square mile. It’s ridiculous. And they can’t hunt there. Bernd Blossey of Cornell and his colleagues, Darragh Hare and Don Waller, talk about this in a recent paper, “Where Have all the Flowers Gone?”. They suggest that the only thing that is going to work is market hunting, year round, until we get back to normal. And the market hunters will not go to the wildest places of Vermont to hunt deer. They’re going to go where the deer are. This is a problem from coast to coast. I just talked to someone in Missouri yesterday. They can’t find any of the wildflowers they used to have. The plants are gone because there are so many deer.
LT: How do you define conservation? How does your definition differ from the definition used by many land trusts—the permanent, legal protection of land?
DT: It’s not so much that my definition of conservation is different, it is what they are targeting to conserve. I grew up with the idea that the only way we’re going to save biodiversity is by preserving places where it hasn’t been destroyed. That’s what land trusts do. “There’s not a shopping center here—we’re going to preserve it.” We want to go to the most wild places and try to protect them. That has been our conservation model for the last century, ever since conservation was invented. And it’s great. But it’s not enough. It’s not working. That’s why we’re in the sixth great extinction. That’s why the UN says we’re going to lose a million species. We have to conserve biodiversity where there are humans too. That’s what’s different about my message. Many land trusts are not talking about saving biodiversity in the middle of suburbia. It’s been a non-target place because biodiversity is essentially gone there.
“We have to conserve biodiversity where there are humans too.”
Seventy-eight percent of the lower 48 states is privately owned. Homegrown National Park wants to empower the millions of landowners in this country to do conservation on their private property. That’s what makes the entire prospect manageable. We’re not saying save it in Africa, save it all over the world. Just save it on your property. That’s all you have to worry about. And there’s a lot of us. So it creates an entire army of conservationists who don’t know they are conservationists yet. But they don’t have to have degrees, they don’t have to know anything about land easements or all the other things that land trusts do. They just have to plant that oak tree, reduce their lawn area, and do the other things that we talked about. It’s actually very simple. These are all things that individual homeowners can do, once they realize that it is their responsibility to do it, and it’s really important to do it. Again, this is a grassroots solution to the biodiversity problem. We absolutely need the local land trusts and the Sierra Club and Audubon. But they’re not enough.
“We’re not saying save it in Africa, save it all over the world. Just save it on your property. That’s all you have to worry about.”
Joe-pye weed, a fall wildflower, is an important source of nectar for many insects. Photo © Liz Thompson
LT: Is there anything else you’d like to say?
DT: The topic I always end with is the one that applies to absolutely everybody. No matter where you live, no matter whether you’re part of the choir, you require healthy ecosystems. You are on this planet, and you exist because of them. If you don’t know that, that’s sad, but now I’m telling you: You require nature, and that means it is your responsibility to help take care of it. That’s the message we need to get to everybody from kindergarten on up. It is our responsibility.
“You require nature, and that means it is your responsibility to help take care of it. That’s the message we need to get to everybody from kindergarten on up. It is our responsibility.”
What we’re doing is returning to the reverence that Indigenous peoples all over the world had for nature, because it was absolutely necessary. If they didn’t revere nature, if they didn’t take care of it, they all perished. It’s as simple as that. And we’re at that stage.
But, there is hope!