Re: Do shrubs poison other plants when overgrazed, and if so, how?

I have seen the same documentary and others like it. I have no first hand experience with this problem. Plants do have some strange methods of protecting themselves. Stress produces properties in plants not normally observed. It is possible when exposed to a specific set of conditions selected plants can produce toxic auxins effecting both plant and animals around them. There are some interesting observations suggesting plants communicate, but I have not seen definitive experiments. I know I have not answered your question directly, but I suggest you look at some of these unusual traits carefully and perhaps you can publish on it in due time.