By Doug Tallamy
Painting by Jimmy Rouse
Doug Tallamy is one of the nation’s leading advocates for each of us becoming earth stewards by restoring nature’s ways right where we live. Author of many books, including Nature’s Best Hope: A New Approach to Conservation That Starts in Your Yard, Doug provides a framework all of us can use to nourish children’s and youth’s development as earth stewards – by including them in any efforts aimed at ecological landscaping .
If you live with at least some green around you, chances are you have never thought of space just outside and next to where you live as a wildlife preserve that represents the last opportunity we have for sustaining plants and animals that were once common throughout the U.S.. But that is exactly the role that built landscapes are now playing and will play even more in the near future. If this is news to you, it’s not your fault. We were taught from childhood that plants are decorations, and our landscapes are for beauty; they are an outlet for expressing our artistic talents and an oasis for having fun and relaxing in. And, whether we like it or not, the way we landscape our properties is taken by our neighbors as a statement of our wealth, our social status, and our willingness to follow cultural norms.
But no one has taught us that we have forced the plants and animals that evolved in North America (our nation’s biodiversity) to depend more and more on human-dominated landscapes for their continued existence. We have always thought that biodiversity was happy somewhere “out there, in nature,” in our local woodlot or perhaps our state and national parks. We have heard little about the rate at which species are disappearing from our neighborhoods, towns, counties, and states. Even worse, we have never been taught how vital biodiversity is for our own well-being.
Somewhere along the way we decided to convert most of our living and working spaces into huge expanses of lawn. We humans have taken 95% of the natural world in the U.S. and made it unnatural. But does this matter? Are there consequences to using almost all of our land to meet human needs without considering the needs of other species? Absolutely, both for biodiversity and for us. Our fellow creatures need food and shelter to survive and reproduce, and we need robust populations of our fellow creatures because they are what run the ecosystems on which we all depend. Although we like nature, we have always felt apart from it; humans are here, and nature is someplace else. The idea that we could coexist in the same place at the same time has never been part of the vast Western or Asian cultures.
Why We Need Biodiversity
For most of us, hearing about the extinction of species triggers a passing sadness, but few people feel personally threatened by the loss of biodiversity. Here’s why you should. Biodiversity losses are a clear sign that our own life-support systems are failing. The ecosystems that determine the earth’s ability to support us are run by the plants and animals around us. It is plants that generate oxygen and clean water, that create topsoil out of rock, and that buffer extreme weather events like droughts and floods. It is insect decomposers that drive the nutrient cycles on earth, allowing each new generation of plants and animals to exist. It is pollinators that are essential to the continued existence of 80 % of all plants and 90% of all flowering plants, and it is birds and mammals that disperse the seeds of those plants and provide them with pest control services.
And now, with human-induced climate change threatening the planet, it is plants that will suck much of that excess carbon out of the air, build their tissues with it, and pump the surplus into the soil for long-term storage – if we would only put them back into our landscapes. Humans cannot live as the only species on this planet because it is other species that create the ecosystem services essential to us. Every time we force a species to extinction, we are encouraging our own demise. Despite the disdain with which we have treated it in the past, biodiversity is not optional. The good news is that extinction takes a while, so if we start sharing our landscapes with other living things, we should be able to save much of the biodiversity that still exists.
Plant choice matters
What will it take to give our local animals what they need to survive and reproduce on our properties? Native plants – and lots of them. This is a scientific fact deduced from thousands of studies about how energy moves through food webs. The general reasoning goes something like this: All animals get their energy directly from plants, or by eating something that has already eaten a plant. The group of animals most responsible for passing energy from plants to the animals that can’t eat plants is insects. This is what makes insects such vital components of healthy ecosystems. So many animals depend on insects for food (e.g., spiders, reptiles and amphibians, rodents, 96% of all terrestrial birds) that removing insects from a food web spells its doom.
But that is exactly what we are doing in our landscapes. For over a century we have favored ornamental plants from Asia, Europe, and South America over those that have evolved right here. If all plants were created equal, that would be fine. But every plant species protects its leaves with a species-specific mixture of nasty chemicals. With few exceptions, only insect species that have shared a long evolutionary history with a particular plant lineage have developed the physiological adaptations required to digest the chemicals in their host’s leaves. They have specialized over time to eat only the plants sharing those particular chemicals.
We used to think this was good. Use “pest free” plants, and our insects will disappear! But an insect that cannot eat part of a leaf cannot fulfill its role in the food web. We have planted Kousa dogwood, a species from China that supports no insect herbivores, instead of our native flowering dogwood (Cornus florida) that supports 117 species of moths and butterflies alone. On milions of acres we have planted Asian goldenraintrees, ginkgos, burning bushes, barberries, autumn olives, privets, bush honeysuckles, Callery pears, Miscanthus, and dozens of other foreign ornamentals instead of our beautiful oaks, hickories, cherries, basswoods, elms, and others, and we have thereby lost the chance to support thousands of species of caterpillars, the most nutritious bird food available.
In the past we designed landscapes as if they weren’t essential parts of our local ecosystems. But if your yard, your neighbor’s yard, your entire neighborhood and township, in fact, all the places in which we live, work, and play, are excused from contributing to our local ecosystems, then the natural world that supports us is whittled down to nonfunctional remnants of its former self. This must change if we hope to avoid the worst of Earth’s sixth mass extinction and to sustain the production of essential ecosystem services. Everyone who owns land has a golden opportunity to enhance, rather than degrade, local ecosystems by including ecological function as a criterion when we choose landscape plants. And everyone who does not own land can become a player in the future of conservation by volunteering for a local park or land conservancy.
The four ecological functions that all landscapes need to perform are: 1) support a diverse and complex food web; 2) manage local watersheds; 3) move carbon from the atmosphere to the soil; and 4) provide food and housing for as many species of native bees as possible. Lawn does none of these things well, so reducing the area we have in turf grass is a logical first step. But plants vary a great deal in how well they achieve ecological goals, so we must choose very carefully the plants we use to replace lawn. A handy tool to do just that can be found on the National Wildlife Federation website. Select ‘Native Plant Finder’ and enter your zip code; a ranked list of ecologically-productive woody and herbaceous plants for your county will pop up.
You are nature’s best hope
Somewhere along the line we assigned earth stewardship to just a few specialists: a few ecologists and conservation biologists. The rest of us have had cultural permission to destroy the natural world whenever and wherever we wanted, using oxymoronic words like ‘development’ and ‘progress’ as rationalizations. This makes no sense; every human being on earth depends entirely on the quality of earth’s ecosystems, so why wouldn’t every one of us bear the responsibility of good earth stewardship?
The ecological approach to landscaping that I have described here is nothing more than basic earth stewardship, but it is stewardship that empowers us all to become forces in conservation. Today’s environmental challenges are so enormous that it is easy to feel helpless, as if one person can’t make a difference – despite the cliché that suggests you can. In this case, however, the cliché is right on
Even if you don’t own land, you can make a difference by volunteering to help your local land conservancy manage its properties, or simply by helping someone who does own property. Either as property owners or volunteers, each of us has the power – and we clearly have the responsibility – to enhance the ecological value of local landscapes. Whether we decide to do so will determine nature’s fate and, ultimately, our own. In that sense, we all are nature’s best hope!