I attended a natural areas management conference earlier this month and heard a presentation by Douglas Tallamy, Chair of Entomology and Wildlife Ecology at University of Delaware.
He argues that since suburbia is our largest regional land use and nature preserves alone are too small to support all the native species that evolved here, we need to plant our yards not with exotic ornamentals but with the native plants that support the herbivore insects that are essential to all other wildlife in the food web.
It may be a bit of adjustment for gardeners to enjoy minor insect feeding on their plants, but if the landscape is diverse enough, the gardens will still be aesthetically pleasing. Tallamy's studies indicate that native trees and perennials support roughly an order of magnitude more native species of lepidoptera (butterfly and moth species) for example, than the most commonly used non-native ornamentals.
Want butterflies and birds and all the other parts of a healthy natural community? Then you need to plant some of the native plants that support the animals that coevolved with them. And if backyard buffer plantings connect to each other the effect is much greater than a single plant in a lawn.
Dr. Tallamy also dovetailed his presentation to one made earlier at the conference by Larry Weaner, a landscape architect who has perfected the art of using natural succession and native plants to promote healthy landscapes (and simultaneously reduce maintenance). Tallamy sent his undergraduate students to the homes of Larry Weaner's clients and to similar homes nearby that were "conventionally" landscaped with non-native ornnamentals. The naturally-landscaped yards had measurably higher wildlife numbers and diversity than the ones that weren't Weaner's clients.
I have long noticed that the native perennials by the porch at home draw many small native bees that are as entertaining as the plants themselves.
After hearing Dr. Tallamy's talk (illustrated with beaufitul photos, many of which were taken in his own backyard) I was newly sensitized to seeing beautiful caterpillars at the Preserve.
Above is the caterpillar of the Io moth (Automeris io) that I spotted on a willow along Pine Creek. (For a view of the adult photographed at our Mariton Preserve click here.) I didn't touch them as spiny caterpillars sometimes cause stinging when handled. Indeed, David L. Wagner in Caterpillars of Eastern North America (Princeton, 2005) notes that the sting of this species can be the same intensity as stinging nettle but longer lasting—and since some people are more allergic than others he doesn't recommend anyone handling (238). But I was sure happy to see these beautiful caterpillars and know their part in a healthy ecosystem.