<<Are there any ecologists on this list who can discuss "positive feedback
switches"? Many plant species change their environment to make it more
suitable for themselves and in so doing decrease diversity--Coastal
redwoods being a primary example cited by many. An extreme example:
Sphagnum spp create "monocultural" bogs from ponds--almost eliminating
diversity and helping more of their species survive. Many ecologists
see stability as associated with lack of diversity. Where ecosystems
are regularly disturbed, diversity is usually far higher, according to
the studies of Reice and others. Extreme diversity and disturbed,
chaotic physical conditions go hand in hand in nature. Many (or can we
say most?) species fight such extreme diversity by creating a stable
environment more conducive to their kind. Diversity increases as
stability decreases.>>
I'm reminded of the kauri (spelling) tree of New Zealand. It is allelopathic,
so much so that eventually it poisons itself. But meanwhile, it has a grand
time bullying the other species around. There is a rather stark wastelands
down at the North tip of the North Island (forget what it is called) that has
sort of a Death Valley look to it, which is the end-product of this ecosystem
succession.
For Mother Earth, Dan Hemenway, Yankee Permaculture Publications (since
1982), Elfin Permaculture workshops, lectures, Permaculture Design Courses,
consulting and permaculture designs (since 1981), and now permaculture
training in an email classroom. Copyright, 1996, Dan & Cynthia Hemenway.
YankeePerm@aol.com P.O. 2025, Ocala FL 3447-2025 USA.
We don't have time to rush.