Thursday, May 08, 2008

Preserving biodiversity begins with native plants at home

Preserving biodiversity begins with native plants at home

Listen to the commentary
Real Audio : MP3 download

There’s something very particular about the diet of monarch butterfly caterpillars, and I bet if you give yourself a moment you can recall it. (If you can’t, just ask the nearest elementary school student.) That’s right, monarch caterpillars feed only on plants in the milkweed family. In doing so they obtain both the nutrients they need to grow and a chemical defense system, since milkweeds contain compounds that are toxic and distasteful to insect eating creatures.

Now ask yourself this: are there any plants in my yard that will sustain monarch caterpillars?

I raise the question in order to introduce a book I’ve been reading lately, called Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens. It’s written by Douglas Tallamy, who is a professor of entomology at the University of Delaware. Tallamy argues convincingly that the preservation of biodiversity in North America must begin at home, with the use of native plants in our yards.

You are probably familiar with some other reasons for using native plants in home landscaping, and Tallamy acknowledges these. Unlike many exotic species, native plants thrive without supplemental watering or the use of fertilizers and pesticides, and so provide us enjoyment without depleting or degrading our water resources. But for Tallamy it is crucial that people come to understand the ecological significance of the choices they make when they plant.

He emphasizes, first, how much of the American landscape has been transformed by agriculture and urban and suburban development. “As far as our wildlife is concerned,” he writes, “we have shrunk the continental United States to 1/20th its original size.” A straightforward ecological calculation tells us that little fragment will support only 5% of the species that were found here when Europeans first arrived.

Thus the only way we can hope to slow the trend toward extinction is to begin remaking our urban and suburban landscapes with native plants. Native plants, in turn, support native insects, which are the key to survival for all other species.

If you’re interested in reading more about the why of landscaping with native plants, I encourage you to pick up a copy of Bringing Nature Home. It really is an eye-opening book.

If you’re ready to start on the how, of landscaping with native plants let me introduce you to two local resources. The first is a book published by University of Illinois Extension, called Native Plants in the Home Landscape for the Upper Midwest. This book describes a wide variety of native wildflowers, grasses, trees, and shrubs that work well in home landscapes and provides specific plans for installing them in gardens that look great, too.

The second local resource you should be aware of is a conservation group, Grand Prairie Friends. Each Spring they grow and sell native plants to raise funds for their efforts and promote biodiversity in our area. The Grand Prairie Friends Native Prairie Plant and Woodland Wildflower sale will take place this Saturday, May 10th, at Lincoln Square Village in Urbana.

Among the plants you can purchase there, few are more beautiful than butterfly milkweed. And if you plant some of that in your yard, you will know where to look for Monarch caterpillars this summer.