[permaculture-oceania] FW: Direct scientific support for permaculture

[Cameron Little]

Forwarded on by Paul Osmond from the US based permaculture at lists.ibiblio.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
>
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