permaculture

[Juergen Botz <jurgen@botz.org>]

Here is some recently published research that lends direct scientific
support to the principles of permaculture:

  http://www.nsf.gov/news/news_summ.jsp?cntn_id=107018&org=olpa&from=news

The link above is to an NSF summary of an article from the June 1
issue of "Nature", one of the most prestigious and widely-read
journals in the natural sciences.  You can download the article 
from the www.nature.com website, but unfortunately the per-article
charge is rather steep at $30.  The link is:

  http://www.nature.com/nature/journal/v441/n7093/edsumm/e060601-11.html

The first paragraph of the article itself reads:

  "Human-driven ecosystem simplification has highlighted questions
  about how the number of species in an ecosystem influences its
  functioning. Although biodiversity is now known to affect
  ecosystem productivity, its effects on stability are
  debated. Here we present a long-term experimental field test
  of the diversity-stability hypothesis. During a decade of data
  collection in an experiment that directly controlled the
  number of perennial prairie species, growing-season climate
  varied considerably, causing year-to-year variation in
  abundances of plant species and in ecosystem productivity. We
  found that greater numbers of plant species led to greater
  temporal stability of ecosystem annual aboveground plant
  production. In particular, the decadal temporal stability of
  the ecosystem, whether measured with intervals of two, five or
  ten years, was significantly greater at higher plant diversity
  and tended to increase as plots matured. Ecosystem stability
  was also positively dependent on root mass, which is a measure
  of perenniating biomass. Temporal stability of the ecosystem
  increased with diversity, despite a lower temporal stability
  of individual species, because of both portfolio (statistical
  averaging) and overyielding effects. However, we found no
  evidence of a covariance effect. Our results indicate that the
  reliable, efficient and sustainable supply of some foods (for
  example, livestock fodder), biofuels and ecosystem services
  can be enhanced by the use of biodiversity."

This is actually a really big deal, because obvious as this finding
may seem to those of us who are permaculture "converts", in science
it is very important to have strong empirical support for your most
basic assumptions... and that diversity enhances stability and
productivity certainly goes to the heart of one of permaculture's 
most basic assumptions.  Having these controlled experimental results
published in "Nature" is powerful ammunition in any argument with
permaculture skeptics.

:j