Even the clear dagger moth caterpillar, which can feed off of many species, cannot digest nonnative plants.
In the past we have ignored the vital role plants play in our landscapes. Plants, of course, are the only organisms that capture energy from the sun and turn it into the simple sugars and carbohydrates: the food that supports nearly all the food webs on earth. Every time we bulldoze a native plant community, we are reducing the amount of food available for our fellow creatures. In fact, the amount of life that can exist in an area is directly proportional to the amount of vegetation in that area. Because plants have physical structure, they also provide housing for animals.
We can no longer landscape with aesthetics as our only goal. We must also consider the function of our landscapes if we hope to avoid a mass extinction that we ourselves are not likely to survive. As quickly as possible, we need to triple the number of native trees in our lawns and underplant them with the understory and shrub layers absent from most managed landscapes. Homeowners can do this by planting the borders of their properties with native trees such as white oaks (Quercus alba), black willows (Salix nigra), red maples (Acer rubrum), green ashes (Fraxinus pennsylvanica), black walnuts (Juglans nigra), river birches (Betula nigra), and shagbark hickories (Carya ovata).
Those trees should be underplanted with woodies like serviceberry (Amelanchier canadensis), bottlebrush buckeye (Aesculus parviflora), arrowwood (Viburnum dentatum), hazelnut (Corylus americanus), and blueberries (Vaccinium spp).
Studies have shown that even modest increases in the native plant cover on suburban properties raise the number and species of breeding birds, including birds of conservation concern. As gardeners and stewards of our land, we have never been so empowered to help save biodiversity from extinction, and the need to do so has never been so great. All we need to do is plant native plants!
Douglas Tallamy is professor and chair of the Department of Entomology and Wildlife Ecology at the University of Delaware.
WHAT TO PLANT WHERE
Certain native staples are essential to any forest restoration within the suburban/urban matrix:
• New England: Sugar maple, white pine, and paper birch
• Mid-Atlantic: White oak, American beech, river birch, and red maple
• Midwest: Bur oak, honeylocust, and crabapple
• Deep South: Live oak, loblolly pine, and tupelo
• Northwest: Douglas-fir, yellow cedar, and beaked hazelnut
However, diversity is the real key to restoring native plant communities.
In New England, for example, consider replacing Norway spruce with Atlantic white cedar, or northern white cedar underplanted with native hawthorns and alternate-leaf dogwood. These plants produce abundant bird food in the form of insects and berries.
In mid-Atlantic states, sycamore is valuable in riparian restorations and biological corridors through suburban backyards, despite its susceptibility to early season anthracnose. Also consider one of the hickories – shagbark for rich, welldrained soils, and pignut, shellbark, or mockernut for upland plantings. The conifer conundrum in the mid-Atlantic states can usually be solved with eastern redcedar, a wonderful evergreen that can be an accent plant anchoring a suburban home, an effective, fast-growing screen, or a formal alley bordering a long driveway.