permaculture

[Paul Cereghino <paul.cereghino@comcast.net>]

Ditto to Rich... and just to be semantic... peer reviewed studies i've 
read describe a range of "edge phenomena", and edges occur at different 
spatial scales and between different kinds of "patches".  And this is 
different but related to island biogeography 
(http://en.wikipedia.org/wiki/Island_biogeography) that describes 
landscape scale patterns of species diversity resulting from population 
isolation.  Productivity can also be controlled by a range of factors, 
and can be measured in different ways.  And diversity can be measured at 
different spatial scales: microsite, patch, site, or landscape.

So the statement  "the edges cause an increase in productivity and 
diversity" contains three concepts that are poorly defined: edges, 
productivity, and diversity -- each has multiple definitions.  And then 
there is the assumption that it is the edge itself that is 'causing' the 
phenomena.  Different phenomena can be observed on forest edges and pond 
edges, and edges between sidewalks and plantings, and sun facing edges 
vs. shade facing edges, and edges of tree driplines, and the edge cells, 
and edges between ideologies.

And some systems are naturally low in floral diversity (like our salt 
marshes), while being extremely productive.  But you could easily argue 
that this productivity is driven by sitting in a wet nutrient sink.  And 
our indians reduced patch diversity to increase yield (cultivating 
silverweed in salt marshes, or removing death camas to facilitate 
harvest of non-death camas).

And then at the landscape scale there is a theory of moderate 
disturbance creating maximum diversity, such that regular modest 
disturbance creates more species richness then extreme disturbance, or 
lack of disturbance.  Harvest can be a kind of disturbance... so we 
create edges at multiple scales over time based on our harvest patterns, 
or is it the creation of the vacant niche rather than the creation of an 
edge that creates the phenomena?

So in short - edges are very interesting, and it is good to think about 
them, and they can be very good places to gather and grow food.  There 
are many hypotheses that could be tested related to edge effects and 
they overlap horribly.  And if you have a hypotheses you want to test, 
you end up spending a lot of time trying to define terms well.

I would say that edges offer opportunities for increasing yield through 
diversifying output and increasing niche complexity (layering and 
stacking), but would not confuse the utility of edges and human induced 
diversity in our planted zones, with ecological theories of natural 
diversity which get more and more complicated, and dependant on multiple 
overlapping factors at smaller and smaller scales.  So this is really 
about recognizing our own human habitat preferences (as Rich said) 
rather then unravelling a 'law of nature'.

~Paul

Rich Blaha wrote:

> As Robyn mentions, the 'Edge Effect' is a long standing ecological term.  Interestingly enough, many in the conservation biology field have a negative view of this phenomenon in its effect upon sensitive species.  
>
> In my work in both Tallgrass Prairie and northwestern US Old growth forests, 
> the fragmentation of habitat allows for invasion of these habitats by 
> 'generalist' species, generally to the detriment of a habitat specialist 
> species.  In forests, increased edge increases the habitat for Marbled 
> Murrelet nest predators, such as Crows, Ravens, and Jays.  In prairies, the 
> edge increases habitat for nest parasites like Cowbirds.
>
> An edge is considered ecologically productive because it is a location that can tap into the resources of 2 different environments.  The shade, coolness, fungal diversity, and biomass of the forest; and the sunlight, fossorial rodents, and nitrogen fixation of the meadow, for example.  
>
> Or to use the shoreline example, the coastal headlands, with their moisture 
> and milder climate than inland locations;  and the nearshore ocean, with its 
> seawood and plankton production.  Add the destructive power of waves, which 
> bring forth a bounty of dead and dying flotsam with each tidal cycle, and 
> sloughs and brackish water (an edge habitat unto itself), which harbor an 
> entirely different, and very productive, ecosystem.
>
> As habitat generalists, humans' preference for edges allows us to tap into 
> the productive capacity of ecotonal environments (a la the forest garden).  
> It's just nice to have options....
>
> Cheers
>
> Rich
> Mossback Farm
> www.mossbackfarm.com/journal
>
>
>  
>
> >  
> >    4. Edges - Re: permaculture and science (Rich Morris)
> >    5. Re: Edges - Re: permaculture and science (Lawrence F. London, Jr.)
> >    
>
>  
>
> >    7. Re: Edges - Re: permaculture and science (Robyn Francis)
> >    
>
>  
>
> >    
>
>  
>
> > ------------------------------
> >
> > Message: 4
> > Date: Fri, 02 Feb 2007 20:01:00 +0000
> > From: Rich Morris <webmaster@pfaf.org>
> > Subject: [permaculture] Edges - Re: permaculture and science
> > To: permaculture@lists.ibiblio.org
> > Message-ID: <45C3987C.1040500@pfaf.org>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > The discussion on permaculture and science got me thinking about some of
> > the hypothesis of permaculture and whether they are testable, and this
> > was brought to mind in a recent comment on
> > http://en.wikipedia.org/wiki/Talk:Permaculture
> >
> > "Sure, coastal areas are more full of life, there's rainfall,
> > temperatures are moderate, but to jump to the conclusion that "edges"
> > are valuable from that seems a stretch. Please provide more evidence, at
> > least in the form of links or delete! Even if there is an advantage to
> > the seashore, the coastal edge is tens of miles wide, while I've seen
> > permaculture designs where there were edges every hundred feet or so, it
> > might not scale down. Permaculture is an essential idea, so it becomes
> > even more important that it doesn't get watered down by New Age
> > superstitions."
> >
> > Theres quite a few places in the permaculture literature where there are
> > claims that edges are the most productive/most diverse. Is their any
> > evidence to support these claims?
> >
> > Rich
> >
> > --
> > Plants for a Future: 7000 useful plants
> > Web:   http://www.pfaf.org/
> > Post:  1 Lerryn View, Lerryn, Lostwithiel, Cornwall, PL22 0QJ
> > Tel:     01208 872 963
> > Email: webweaver@pfaf.org
> > PFAF electronic mailing list http://groups.yahoo.com/group/pfaf
> >
> >
> >
> > ------------------------------
> >
> > Message: 5
> > Date: Fri, 02 Feb 2007 15:12:34 -0500
> > From: "Lawrence F. London, Jr." <lfl@intrex.net>
> > Subject: Re: [permaculture] Edges - Re: permaculture and science
> > To: permaculture <permaculture@lists.ibiblio.org>
> > Message-ID: <45C39B32.2000802@intrex.net>
> > Content-Type: text/plain; charset=us-ascii; format=flowed
> >
> > Rich Morris wrote:
> >
> > > The discussion on permaculture and science got me thinking about some of
> > > the hypothesis of permaculture and whether they are testable, and this
> > > was brought to mind in a recent comment on
> > >     http://en.wikipedia.org/wiki/Talk:Permaculture
> > >
> > > "Sure, coastal areas are more full of life, there's rainfall,
> > > temperatures are moderate, but to jump to the conclusion that "edges"
> > > are valuable from that seems a stretch. Please provide more evidence, at
> > > least in the form of links or delete! Even if there is an advantage to
> > > the seashore, the coastal edge is tens of miles wide, while I've seen
> > > permaculture designs where there were edges every hundred feet or so, it
> > > might not scale down. Permaculture is an essential idea, so it becomes
> > > even more important that it doesn't get watered down by New Age
> > > superstitions."
> > >
> > > Theres quite a few places in the permaculture literature where there are
> > > claims that edges are the most productive/most diverse. Is their any
> > > evidence to support these claims?
> >
> > Marine estuaries are edge zones. How important are they? Very, as they
> > provide in some cases the only breeding ground available to many marine 
> > organisms.
> > Include in that rivers that merge with sounds and then the ocean.
> > Fish swim upstream to breed. So the distinction gets blurred, river as edge 
> > zone,
> > but in the context of one of the most important functions of edge zones, 
> > habitat
> > for breeding, it qualifies.
> > --
> > Lawrence F. London, Jr.
> > Venaura Farm
> > lfl@intrex.net
> > http://market-farming.com
> > http://market-farming.com/venaurafarm
> > http://venaurafarm.blogspot.com/
> > http://www.ibiblio.org/ecolandtech
> >
> >
> >
> >    
>
>  
>
> > Message: 7
> > Date: Sat, 03 Feb 2007 09:52:08 +1100
> > From: Robyn Francis <erda@nor.com.au>
> > Subject: Re: [permaculture] Edges - Re: permaculture and science
> > To: permaculture <permaculture@lists.ibiblio.org>
> > Message-ID: <C1EA0BC8.27B1%erda@nor.com.au>
> > Content-Type: text/plain;        charset="US-ASCII"
> >
> > Edge effect is not a permaculture invention or new age superstition, it's a
> > recognised phenomena in the science of ecology--the technical term is an
> > ecotone. Whereas ecologists simply observe and record the diversity and
> > productivity of naturally occurring edges, permaculture takes it a step
> > further and consciously builds it beneficially into design. Many of the
> > common production-system edges employed in permaculture can be found in
> > traditional and indigenous systems.
> >
> > And everything is relative, oceans and landmass are big systems with big
> > edges, smaller systems will have smaller ecotones. This starts to get into
> > the arena of fractals and patterning, the understanding of which is
> > intrinsic to good design.
> >
> > Ciao
> > Robyn
> >
> >
> > On 3/2/07 7:01 AM, "Rich Morris" <webmaster@pfaf.org> wrote:
> >
> > > The discussion on permaculture and science got me thinking about some of
> > > the hypothesis of permaculture and whether they are testable, and this
> > > was brought to mind in a recent comment on
> > > http://en.wikipedia.org/wiki/Talk:Permaculture
> > >
> > > "Sure, coastal areas are more full of life, there's rainfall,
> > > temperatures are moderate, but to jump to the conclusion that "edges"
> > > are valuable from that seems a stretch. Please provide more evidence, at
> > > least in the form of links or delete! Even if there is an advantage to
> > > the seashore, the coastal edge is tens of miles wide, while I've seen
> > > permaculture designs where there were edges every hundred feet or so, it
> > > might not scale down. Permaculture is an essential idea, so it becomes
> > > even more important that it doesn't get watered down by New Age
> > > superstitions."
> > >
> > > Theres quite a few places in the permaculture literature where there are
> > > claims that edges are the most productive/most diverse. Is their any
> > > evidence to support these claims?
> > >
> > > Rich
> >
> >
> >
> >
> >    
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