Douglas Tallamy, Professor of Entomology and Wildlife Ecology of the University of Delaware presents an open and shut case for not only planting native plants, but going the extra mile to eradicate the alien plants in your yard or on your land. After you read this book you’ll find yourself compelled to spread the word, not simply for aesthetic or practical reasons, but to save all life on Earth. Seriously, that’s how I felt after reading just a few pages.
Tallamy’s flash of insight arrived when he and his wife moved to a ten-acre farm in Pennsylvania. As an entomologist, he was startled by the lack of insect damage—and insect life—on the exotic plants that were aggressively replacing the native vegetation. His investigation of exactly who eats what—and why exotic plants are truly dangerous—is presented in this book.
Here’s the first important fact. Herbivorous insects convert plants into food for numerous amphibians, reptiles, birds, and mammals. For example, fully 96 percent—yes, 96 percent!—of terrestrial North American birds rely on insects and other arthropods, usually the spiders that eat insects, to feed their young.
Here’s the second important fact. Exotic plants, often valued because they are not touched by insects, support a relatively small number of insect species. What does this mean? Less insect biomass. For example, the author’s research in Pennsylvania showed that native woody plants support 35 times more caterpillar biomass, the preferred source of protein for bird nestlings, than alien woody plants provide. It is an understatement to point out that this can make the difference between a successful breeding season and severe decline of a local population.
After explaining why insects can’t eat alien plants, providing a brief overview of the true cost of exotic ornamentals, and letting us know why our gardens are better off if we actually feed the local insects, the author launches into a 40-page whirlwind tour of North American woody plants that sustain insects and, indirectly, other organisms. Why woody plants? Folks are already interested in providing nectar and pollen for adult butterflies and moths, but there’s not so much interest in feeding the caterpillars… and you can’t have one without the other. This section of the book is enjoyable for the natural history alone. The reader learns that oaks (which are preferred by 105 insect species) can “churn out caterpillars from May to October”, bats eat the adult stage of the tent caterpillars that thrive on cherry and plum trees, and forest birds benefit immensely during outbreaks of spruce budworm (an important food for nestlings).
Douglas Tallamy continues with a 60-page chapter entitled “What Does Bird Food Look Like?” Again, it is worth reading for the natural history alone. But the numerous anecdotes and references to research—fully documented if one wishes to read the original journal articles—drive home the point that much of the life we see flying and crawling around us is quite dependent upon an army of insect and other arthropod species consuming plants… and one another. The reader gets to meet some familiar and not so familiar herbivores and predators and learn about their roles in ecological communities. There are exceptional close-up colored photographs accompanying the descriptions and I found my self saying over and over, “So that’s what I saw when I walking around last summer!” I now I want to learn even more about these critters.
The author concludes with a FAQ section that helps us understand why insect or bird activity around a given alien plant is not a sign that all is well and offers some advice for winning over the neighbors who might object to your wild and insect-infested gardens.
This is not exactly a how-to book, but a motivational and inspirational book. Douglas Tallamy lives in Pennsylvania, is primarily interested in forests, and writes from his own experience. Not all the plants and insects listed in the appendix are found in the Midwest, but it certainly serves as an excellent starting point for your own investigation.
I encourage folks to read this book for several reasons. You’ll know why alien plants are a threat. You’ll know why you should always plant native species instead of alien species. You’ll be able to explain why to other people. And you might be motivated to look into what’s happening in your own region of the country and share the information with others before it is too late. I hope someone will write a similar book for the Midwest.
Most important, given the extent of fragmentation of habitat and numerous other threats to plant and animal species, the reader will walk away realizing that every garden, every plot of land, every container on your patio is essential for preserving the biodiversity around us.
According to Douglas Tallamy…
“But now, for the first time in its history, gardening has taken on a role that transcends the need of the gardener. Like it or not, gardeners have become important players in the management of our nation’s wildlife. It is now within the power of individual gardeners to do something that we all dream of doing: to “make a difference.” In this case, the “difference” will be to the future of biodiversity, to the native plants and animals of North America and the ecosystems that sustain them.”
I’d like to thank the Mound Vue Garden Club for donating a copy of this book to the Mount Horeb Public Library. I found it by chance while perusing the “new book” shelf and thoroughly enjoyed learning about this subject. I’ll be purchasing a copy for my home library.
This book review originally appeared in the Blue Mounds Area Project Summer 2009 newsletter. The Blue Mounds Area Project is a community-based organization that seeks to inspire, inform, and empower private landowners in the Southwestern Wisconsin region to enjoy, protect, and restore native biodiversity and ecosystem health.