Saturday, July 11, 2009

Why Native?

I try to encourage people to plant native in their yards, but it is often hard to prove that this is better for the local wildlife.

Last year at the Texas Master Naturalist annual meeting, I found a book, Bringing Nature Home, by Douglas Tallamy. This book provides actual data to show the difference between the number of species supported by native plants versus invasives. The author lives further east, so many of his examples are from the eastern US; however, the principles are the same.

For example, there are about 80 species of oak trees in the US. It has been documented that these oak trees support 517 species of butterfly. Willow support 456. Conversely, he documents that even trees that have been in the US for many years, don't support near the number of species of native plants, nor the number of species they supported in their original homeland. So, for example, although Clematis vitalba has been in North America for 100 years, it supports only one species of herbivore here (versus 40 species in its homeland.) Even Phragmites australis, which has been in North America for over 300 years, supports only 5 species of herbivore in the US, versus 170 species in its native land.

The book provides suggested plantings for various areas of the country and also a list of plants to encourage butterflies and moths.

A very interesting book with lots of photos; well worth buying.

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