Wildlife References & Resources
Native Plants for your Front Yard
Chapter 6 mentions the importance of including plants in your garden that are native to your specific region. Why are natives important? Don’t bees and butterflies visit many non-native flowers as they move through the landscape? What’s the difference between natives and non-natives? Why the concern?
The Case for Native Plants The need for concern is more urgent than many realize. Professor Douglas Tallamy, Entomologist from the University of Delaware, has been studying this issue for many years, conducting meticulous research on the relationships between native plants and animals, particularly insect populations, and the measurable impact of their mutual decline upon ecosystem and ultimately, human health. Dr. Tallamy published his findings in Bringing Nature Home: How You Can Sustain Wildlife with Native Plants. In this informative, inspiring, and at times very entertaining book, Dr. Tallamy explains very clearly why we should be concerned about declining biodiversity, the ecological impacts of using predominantly alien ornamentals in our landscapes and outlines tangible steps for creating gardens that promote a healthy diversity of insects. Key concepts include:
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- Birds need bugs. When rearing their young in the spring, the early bird wants the worm (or insect or larvae), not birdseed or berries. In fact, 96% of our birds rear their young on insects! No insects, no birds. They (and other animals including amphibians, reptiles, mammals and arachnids) need the proteins in insects to survive and breed.
- Bugs that eat plants have highly specialized diets. Native plants and insects have co-evolved over millennia to adapt to each other and there are very specific plant insect relationships. Non-native plants do not support food webs and are inedible to most native fauna. Unfortunately, labeling an alien garden plant “pest free” increases the market value.
- Ecosystems are increasingly vulnerable. As developed landscapes continue to replace native species with decorative and exotic plants, our entire ecosystem is at increasing risk of collapse, due to systemic elimination and fragmentation of functional habitat. Dr. Tallamy describes this as the “Jenga Hypothesis” in that, like the Jenga game, one never knows when the entire structure will collapse.
- Balanced food webs protect plants. If you plant enough native plants, you will attract enough insects that eat plants to support a healthy community of natural enemies, such as insect predators, spiders and birds. Natural enemies will keep insect damage to your plants to a minimum.
The following tables illustrate the difference between native and non-native plants and their ability to support insect populations. Both tables note the number of Lepidoptera (moth and butterfly) species various native trees will support. Why moths and butterflies? Dr. Tallamy chose this group as they represent over 50% of all insect herbivores in this country; caterpillars are an important food source for many vertebrates, including birds; and there is more available published research on Lepidoptera and their use of native species than other herbivores.
You can use this information as a general guide when considering which native plants to include in your garden. Within each bioregion there are multiple habitats and microclimates, and species will vary by region. For example, the coast live oak (Quercus agrifolia) is native to California, while the red oak (Quercus rubra) is from the Eastern US.
Table reprinted from Bringing Nature Home by permission of the author, Douglas Tallamy
Note that the mighty Oak tree can support over 500 distinct species of caterpillars alone! Professor Tallamy chose to study this group of invertebrates as their larvae form a major component of bird’s diets. By comparison, his research found that the following popular landscape plants provide little to no value:
Table reprinted from Bringing Nature Home by permission of the author, Douglas Tallamy
The health of our eco-systems is absolutely dependent upon reintroducing natives into our gardens. Visit KissYourGrassGoodbye.com for recommended plant lists and references to help you develop plant palettes that will support a diverse and balanced food web which, in turn, will contribute to a sustainable ecosystem. Visit Doug’s websites at bringingnaturehome.net and plantanative.com for more information. You may want to purchase his book for your personal reference library, it is very informative with hundreds of full-color photos of native plants and the bugs we want to attract to our gardens.
