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  • From: Scott Pittman <pci@permaculture-inst.org>
  • To: "permaculture" <permaculture@franklin.oit.unc.edu>
  • Subject: RE: all theory thread DESIGN PRINCIPLES used in our course notes.
  • Date: Mon, 28 Aug 2000 12:13:24 -0600

I agree with Ava's thoughtful reply and would like to add my own dilemma regarding native versus non-native plants.

Most of what I grow in the garden for food are European table vegetables.  What isn't from Europe is originally from Peru (potato) , Mexico (corn), Africa (okra), Asia (dikon).  My eggs come from poultry that originated in Asia.  Some medicinals hail from Siberia.  While I have led the good fight against Russian Olive (Elaeagnus angustifolia) which is claiming our riparian areas I recently realized that without the Russian Olive these riparian areas would have no overstory at all.  Since flooding is no longer allowed to occur the "native" cottonwoods are no longer germinating and they were the primary riparian overstory plant in Northern New Mexico.  Since Russian Olive germinates at the drop of a hat (or the drop of a bird scat)  it is has very successfully filled this empty niche and is doing a good job of preventing erosion, providing shade for understory species, sustaining bird populations, and who knows what other benefits.  Until we can reintroduce flooding in our riparian zones it seems that this pioneer is doing an invasively good job.  The Salsola kala (tumbleweed) from Australia is another pestiferous plant that pioneers bare soil and holds it in place until it is succeeded by a more desirable, occasionally, native plant.  The list of non-native plants is endless and many of them provide a service in niches that would otherwise deteriorate through erosion. 

A problem I have is looking for broad canopy overstory plants, that fix nitrogen, in order to mitigate light saturation in the high desert.  How I long for those tropical legumes to provide light shade for my field.  My plants suffer through the summer, even with high moisture content, because of heat and light saturation; photosynthesis stops around noon so my plants short growing season is further shortened by inactivity.  The ideal plant would have a high broad canopy, fix nitrogen, have grey green or silvery foliage to resist ultraviolet, provide light shade, and be drought tolerant. I finally settled for Honey Locust (Gleditsia spp.) which is native to the East coast USA, and central America but not here,  Though Gleditsia provides many of the functions I am looking for it doesn't satisfy them all.  Robinia spp. would have given me the nitrogen but suckers too much for a field crop situation and has a more erect canopy than I want.  What else is there that provides the multiple functions I am looking for and is native?, and native to where?  Is the East coast native?; is southern New Mexico native?  I guess it depends on your definition and seems to be more bound up with geo-political boundaries than biomes.

I think that the ecofascism label is often misapplied to people who are concerned with rampancy and over competition from exotic species introduction but I have certainly encountered what I would call ecofascism from those who think that all non-natives are verboten and their intolerance knows no bounds.  I'm personally not sure what a native truly is because one has to pick a particular geologic time to define what is native.  What is desert today and is filled with drought tolerant "natives" was once a sonorous (Sonoran Desert) wet climate with a completely different set of "natives"; are those past natives now exotic to their past home?  Are we talking about native to place, or climatic situation, or soil types? 

I know it is our responsibility to proceed with caution and lots of thought and research but ultimately I think we will have to use whatever is most suitable to our ultimate goal of restoration and creating sustainable situations in our immediate environment.  Most of us are looking at remnant environments anyway and don't have a clue what was in our environment before over grazing, clear cutting, mining, climate change, increased ultraviolet radiation, and other man created changes produced what we are looking at today.  Well, we do have some clues but the total story is still somewhat vague.  Rather than wait in the indecisive clutch of native versus non-native I think it better to try and rebuild a healthy functioning ecosystem using the best of the natives but not being afraid to use analog species for those niches that are critical for the functioning of the whole.

Scott




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