Thursday, May 1, 2008

Nature, Gardens, Logic and the Future of Earth

In March I wrote about Douglas Tallamy's book, Brining Nature Home, on the basis of a book review and a pod cast. Having read about 1/3rd, I feel an urgent need to expand on the basic point.


The reason is amazingly simple: non-"native" plants have not co-evolved with the insects and birds and animals in a given area. They are immune (good selling point in the bad old days) from "pests." They are like plastic flowers to local insects.

Birds need massive amounts of protein, particularly when they are raising they hatchlings. Insects, particularly those that eat leaves, like caterpillars (that turn into butterflies) and the like, are a higher source of protein than beef.

So, when the insects go, can't survive on the plastic diet of non-native plants, the birds vanish. Slowly, perhaps, but vanish.

At the same time, non-native plants, that don't have "pest" insects to keep their numbers in balance by eating their leaves, (and trunks, and sap, etc.), proliferate in their new environment. No enemies. Wheeeee. Plus, the birds that eat the fruit of the non-native plants fly away and poop elsewhere, fabulously spreading the seeds of the non-natives, who begin to flourish in a new area, clear of "pests."

Finally, he makes the point that the importation of non-natives, beautiful exotics, has inevitably brought plant diseases with them. No amount of protective agricultural laws can keep out microscopic infestations. The imported plants co-existed and co-evolved with the imported exotic. But, domestic plants didn't. They had zero evolved protection from predation by the new plant diseases.

And, voila, the death of the American Chestnut, majestic trees that populated the whole east coast, the death of the elms, the approaching death of conifers native exclusively to the Smokies, and so on.

So, we have kudzu, pansies, giant irisis, Japanese Maples, peonies, roses, any plant from any where else but where it co-evolved in the web of local natural life. All of which contribute to the death of nature around us.

Kill all the English Ivy you can find!