“Unless we restore native plants to our suburban ecosystems, the future of biodiversity is slim” because “most of our native plant eaters are not able to eat alien plants.” In many places, “there is no place left for wildlife but in the landscapes and gardens we create.” If you want wildlife around you to survive, it needs to find food, shelter and nest sites on your land, and you need to bring back the native plants it desires the most.
Insects: This planet has 4 million insect species, over 300,000 species of beetle, yet only around 9,500 species of birds. “30% of all animals are beetles.” “Pound for pound, most insect species contain more protein than beef.” Insects pollinate, return nutrients to and aerate the soil, and provide food for tons of animals. If there were no insects on earth, no people would be alive. But if there were no people on earth, insects would do just fine. “A large percentage of the world’s fauna depends entirely on insects to access the energy stored in plants” (Wilson 1987).
Plants are the first trophic level; the second trophic level are all the animals that eat plants (herbivores or phytophages). Moths are nocturnal while butterflies are diurnal (strangely, social butterflies are very active at night so perhaps the Kardashians more accurately should be called social moths, moths also being obsessed with being in the spotlight). Moths are more fragile to touch and are fatter than butterflies.
In 1900, 60% of Americans lived rurally; in 2000 that figure was down to 17.4%. By 2003, less than 1% of Pennsylvania is considered “wild”. Of course, too much of the US is paved, but on top of that, the American lawn involves alien grasses – total lawn area in the present US covers eight times the size of New Jersey. Wood thrushes (my favorite local bird call) are tropical migrants as are warblers, cat birds, hawks, wrens, vireos, flycatchers, swallows, tanagers and orioles. They are must fly thousands of miles to spend winter in Central or South America. These migrating birds sadly have been declining at a rate of 1% per year since 1966. An estimated billion birds a year die by flying into windows. When people tell you there are more birds here than ever, they are thinking about invasive species like European starlings and house sparrows. Diversity is most important when each species contributes to the local ecosystem. Factor in that “aliens colonize disturbed areas more than do native plants”; thus, mowing native areas risks alien intrusion.
How alien plants hurt your backyard: a lot of ornamental plants were introduced in the US because our insects avoided them. Alien plants didn’t need insecticide, and few cared that healthy environments must support insects. Many ornamentals escaped cultivation and began replacing natives. Native plants aid native wildlife – e.g. Eucalyptus trees in native Australia host 48 insect species, but the same trees in non-native California host only 1 species. It takes long evolutionary time for insects to adapt to a new alien’s chemical makeup. Because these new plants now don’t have natural enemies, they can out compete most native plants. Aliens outcompete our natives by not having insect enemies that want to eat that plant. Darwin noticed in South America that transplanted aliens out competed native plants forming a kind of monoculture.
Trees: No two species of tree have the same leaf chemistry; insects will need long time to be able to metabolize the leaf in question. Douglas Fir grows native to the Pacific Northwest, you can grow it in Oxford, Pennsylvania but it won’t function as a native there. The same is true of blue spruce, which is native to Western Colorado, but not an eastern suburb. Chestnut blight arrived from Asia in the Northeastern US in 1878; it killed off the American chestnut trees in fifty years. The lust for alien Japanese Chestnuts, destroyed the American chestnut.
Trees are carbon sinks – they hold carbon. A single large sugar maple tree can sequester 450 pounds of carbon per year. As long as the tree is alive, it will sequester carbon, offsetting climate change. Cage new planted trees with temporary 5-to-6-foot fences if you have a deer problem; deer eat lower branches, and you don’t want them taking out the whole tree because it’s still too short. On page 147, is a terrific charting how many butterfly species support each tree in the US. For example, Oak supports 534 species while Beech only supports 126 species.
Aliens: Alien plant attacks even affect our national parks, “The Great Smokey Mountains National Park, has been invaded by over 300 species of alien plants.” Alien nursery stock has a long history of bringing foreign diseases and pest into this country. Lawn mowers use lots of energy; mowing your alien lawn for one hour a week pollutes as much as driving 650 miles.
To best get butterflies on your patch of land, plant milkweeds and butterfly weed. Make sequential cuttings of your milkweed patches once a month in summer through to Fall to assure your Monarch larvae have “tender young milkweed leaves to eat”. Birds hunt for caterpillars not by looking for caterpillars, but by looking from a distance for damage done to leaves. Turn off outside lights at night to help moths.
What maintains local bird populations are not the commercial bird seed you leave out for the adults, but the amount of food (insects like larvae, worms, caterpillars, and the like) birds can only feed their little ones. We don’t know much about cicadas because they spend most of their lives underground sucking on tree roots.
If you want berries in your yard, plant arrowwood, elderberry, alternate-leaf dogwood, Virginia creeper, spicebush, black chokeberry, winterberry, native hawthorns, or red cedar. If you want Chuck Berry in your backyard, prepare to grave rob.
This book and Doug’s other one (Nature’s Best Hope) are wonderful ways to drive home the importance of all of us replacing our lawns right now with native plants to give nature and wildlife a better chance than they are presently getting. Everyone at my place spends a lot of time pulling up invasive Japanese stiltgrass and planting natives to make this (actively helping wildlife) happen; now you can too. Great book, highly recommended.