the more diversity the better?

James V. Worstell (jvworstell@juno.com)
Sun, 17 Nov 1996 18:06:25 PST

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.

While decrying the pesticide-laced Illinois cornfield or Mississippi
cotton field, one need not make the inferential leap to "the more
diversity, the better."

If these species had listservs they'd probably not say "diversity is bad"