In the spring a suburban homeowner’s fancy lightly turns to thoughts of lawn.
Originally uploaded by garethjmsaunders.
Fertilize! Break out the emergent herbicide! Fire up the sprinklers! Here comes the lawn mower and weed whacker! The relentless battle to maintain a time-, energy-, and resource-consuming monoculture that provides a perfect habitat for Japanese beetle grubs has begun!
Or maybe…just maybe…you could try something different this year. Douglas Tallamy, University of Delaware professor of entomology and wildlife ecology, hopes you will, and tells you why you should in his lavishly illustrated book Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens. This book is worth the price if only for the many beautiful photos of insects and native plants.
Tallamy asks, “Is biodiversity necessary or not? Are there measurable consequences, beyond a sense of loss, from reducing biodiversity, and, if so, what are they?” He answers in the affirmative, and details the devastating consequences of reduced biodiversity in accessible and unabashedly passionate prose. Once you start this book you cannot put it down.
His thesis is straightforward: if we take away their sources of food and shelter, wild critters just aren’t going to be there in the future. Because we’ve carved up and built over their native habitat, our suburban gardens have got to pick up the slack. We can have beautiful gardens for our own pleasure that are also welcoming homes to insect herbivores upon which all higher forms of life – including humans – depend. Therefore, we must reduce our use of alien plant species and replace them with native plants. And rip out those invasive aliens wherever you see them!
In a nutshell, this is how we have endangered our native biodiversity. First, we carved up and built over existing native habitat. Then, with what urban and suburban space we have left for gardening, the vast majority of it is dedicated to a monoculture – lawn – that supports almost no wildlife. On top of that, our garden beds are filled with alien ornamental species that our native insects cannot eat. The final insult is that many of these aliens have “escaped” our gardens to become invasive species in the wild, out-competing and crowding out native plants. They also bring with them pests – such as the Japanese beetle – that have no natural enemies here, or devastating diseases such as Dutch elm disease.
Some seriously troublesome data:
[Landscape ecologists estimate] that 3 to 5 percent of the land remains as undisturbed habitat for plants and animals…The 2002 USDA Census of Agriculture tells us that 41.4 percent of our land is in agriculture, which means that we have converted 53.6 to 55.6 percent of the land to cities and suburbia. As far as our wildlife is concerned, we have shrunk the continental United States to 1/20 of its original size. And because our refuges and woodlots are not contiguous habitats, but survive as scattered islands from coast to coast, the effective size of undisturbed land in the United States is far smaller than those statistics indicate. When extinction adjusts the number of species to the land area that remains for the plants, mammals, reptiles, birds, and invertebrates of North America (something that will happen within the lifetimes of most of us), we will have lost 95% of the species that greeted the Pilgrims.
If we are going to avoid this dismal future, then our suburban gardens must be transformed into native habitat – “functioning, sustainable ecosystems with high species diversity.” The keys are native plants in a multi-storied landscape, from ground cover to perennials to shrubs to small and large trees. Did you know that oak trees support 517 different species of Lepidoptera? Maybe the single best thing you can do to support biodiversity is to plant an oak tree.
But if your yard doesn’t have room for oak trees, don’t despair. There are plenty of other small trees, shrubs, perennials, and groundcovers that you can choose from. Tallamy includes a chapter called “What Should I Plant?” that is helpful in this regard. There is also an apendix of suitable native plant species in each category. This list is tailored to the Mid-Atlantic region only, but don’t let this stop you from buying the book. Reading this book will inspire and guide you. You can find local sources for native plants and advice on gardening with them. Just googling “gardening with native plants” will give you a good start.
If you are a teacher, National Geographic has developed a lesson plan on designing a native plant garden.
But wait, you say, I have a butterfly bush in my yard and I see tons of butterflies on it every year. Why shouldn’t I continue to use this alien plant? Sure, butterflies can get nectar from the butterfly bush, but no native butterflies can use it as a larval host plant. If you want to support butterflies throughout their life cycle – and thus help ensure there will be butterflies in our future – replace your butterfly bush with its native equivalent, butterfly weed.
Originally uploaded by ideonexus.
Milkweed plants, coneflowers, black-eyed Susans, buttonbush, and Joe-Pye weed are excellent choices as well. Plant a black cherry to provide support for tiger swallowtails – and take pride in knowing you are providing food and shelter for over 400 other moth and butterfly species.
You don’t want a bunch of insects in your garden, because you want your plants to “look nice”, e.g., not have any insect damage? Tallamy explains why and how you can support a vibrant insect population and still have nice-looking plants. And you’ll be providing food for birds and other animals that depend on insects for their diet.
If you are a gardener, you simply must read this book. If your yard is just all lawn and few ornamentals, you need to read this book, too. It’s as well-documented, powerful, informative, and urgent as anything Al Gore ever presented. It will make you feel alarmed about the dangers we are facing, but it will leave you hopeful that you – you! all by yourself! – can do something that will make a meaningful difference. You needn’t just worry about habitat destruction abroad and satisfy yourself with donating money to preservationist causes. You can take action locally – you can turn your home into an important part of the ecosytem. If I do it, and you do it, and a few others do it…pretty soon we’ve got a trend. Most rewarding of all, you can see real results within a year of beginning to garden with natives. Tallamy describes the changes he and his family have observed over the years in their own yard. It’s intoxicating reading.
It’s spring – let your gardener’s fancy lightly turn to thoughts of the native plants you can grow this year. Join me in gardening for life.