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<DIV dir=ltr align=left><SPAN class=390483312-09042011><STRONG><FONT
face=Arial>I once read a review on fire managed ecosystems maintained
for millennia by the original inhabitants in the East. Fortunately,
they managed natural fires rather than setting new fires.
Cheers.</FONT></STRONG></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=390483312-09042011><STRONG><FONT
face=Arial></FONT></STRONG></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=390483312-09042011><STRONG><FONT
face=Arial>Marc Imlay, PhD<BR><BR>Conservation biologist, M-NCPPC<BR><BR>Board
member of the Mid-Atlantic Invasive Plant Council,<BR><BR>Hui o Laka at Kokee
State Park, Hawaii<BR><BR>Vice president of the Maryland Native Plant
Society,<BR><BR>Chair of the Biodiversity and Habitat Stewardship
Committee<BR><BR>for the Maryland Chapter of the Sierra
Club.</FONT></STRONG><BR><BR></SPAN></DIV>
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<DIV dir=ltr align=left><FONT size=2 face=Tahoma><B>From:</B>
apwg-bounces@lists.plantconservation.org
[mailto:apwg-bounces@lists.plantconservation.org] <B>On Behalf Of </B>Ty
Harrison<BR><B>Sent:</B> Tuesday, April 05, 2011 3:26 AM<BR><B>To:</B>
apwg@lists.plantconservation.org<BR><B>Subject:</B> [APWG] Fw: Ideas for
thought.<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><FONT size=2 face=Arial>Please find below an interesting essay by Toby
Heminway, the polyculture guru, which members of APWG may like to
discuss. Some of his points deserve a critical analysis. I'm not
sure we can accept some of his generalizations. Are we really wasting
time and money figting invasives? Regards, Ty Harrison</FONT></DIV>
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<P class=MsoNormal>Native Plants: Restoring to an Idea</P>
<P class=MsoNormal>Thursday, December 02, 2010 3:44 PM</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Let me tell you about the invasive plant that scares me more
than all the others. It’s one that has infested over 80 million acres in the
<ST1:COUNTRY-REGION w:st="on"><ST1:PLACE
w:st="on">US</ST1:PLACE></ST1:COUNTRY-REGION>, usually in virtual monocultures.
It is a heavy feeder, depleting soil of nutrients. Everywhere it grows, the soil
is badly eroded. The plant offers almost no wildlife habitat, and since it is
wind pollinated, it does not provide nectar to insects. It’s a plant that is
often overlooked on blacklists, yet it is responsible for the destruction of
perhaps more native habitat than any other species. Research shows that when
land is lost to this species, native plants rarely return; they can’t compete
with it. It should go at the top of every native-plant lover’s list of enemies.
This plant’s name: Zea mays, or corn. Corn is non-native. It’s from <ST1:PLACE
w:st="on">Central America</ST1:PLACE>. Next on my list is the soybean, with 70
million acres of native habitat lost to this invasive exotic. Following those
two scourges on this roll call of devastating plants is the European invader
called wheat.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Wait, you say: these plants are deliberately spread by
people; that’s different! But to an ecologist, it is irrelevant that the
dispersion vector of these plants is a primate. After all, we don’t excuse holly
or Autumn olive, even though without bird dispersal, they could not spread. Why
are corn, soy, and wheat not on any blacklists? Because we think of them
differently than plants spread by non-humans. This suggests that an invasive
species is an idea, a product of our thinking, not an objective phenomenon. When
we restore land, we restore to an idea, not to objective criteria.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Let me give another example of how our ideas dictate which
species we’ll tolerate and which we won’t. The wooded hillside on rural
<ST1:STATE w:st="on"><ST1:PLACE w:st="on">Oregon</ST1:PLACE></ST1:STATE> where I
once lived was thick with 40- to 120-year-old Douglas fir and hemlock.. But as I
walked these forests, I noticed that scattered every few acres were occasional
ancient oak trees, four to six feet in diameter, much older than the conifers
and now being overtopped by them. I realized that in these ancient oaks I was
seeing the remnants of the oak savanna that had been maintained for millennia by
fire set by the original inhabitants, the Calapuya people. The fir forest moved
in when the whites arrived and drove off the Calapuya, and suppressed fire. So
what I was seeing was a conifer forest created by human-induced
fire-suppression, and it had replaced the oak savanna that had been preserved by
fire setting. Which was the native landscape? Both were made by humans. If we
say, let’s restore to what existed before humans altered it, we’d need to go
back to birches and willows, since humans arrived as the glaciers retreated. But
clearly that’s not appropriate.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>In a similar vein, one of the rarest and most valued
ecosystems in the Northwest are the native prairies, such as those found in the
<ST1:PLACE w:st="on">Willamette</ST1:PLACE> and other valleys. Yet these
prairies are also the product of human manipulation. Prairies occurred naturally
in the <ST1:PLACE w:st="on">Willamette</ST1:PLACE> over 5000 years ago, but
began to disappear after that. Ecologist Mark Wilson has written “As climate
turned cooler and moister 4,000 years ago, oak savanna and prairie ecosystems
were maintained only by frequent fires set by native people to stimulate food
plants and help in hunting.” The local people used fire technology to maintain
an environment that supported them even when the climate no longer supported
that ecosystem.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>So I applaud and encourage efforts to preserve native prairie
in the region—they are valuable as endangered species habitat, examples of
cultural heritage, and a way of preserving planetary biological wisdom. But we
should restore these prairies with the strict recognition that we are
creating—not recreating or restoring--a state that can not be supported by
current climate and other conditions. Prairies are artificial in the <ST1:PLACE
w:st="on"><ST1:PLACENAME w:st="on">Willamette</ST1:PLACENAME> <ST1:PLACETYPE
w:st="on">Valley</ST1:PLACETYPE></ST1:PLACE>. The preservation of prairies there
isn’t a matter of simply repairing and replanting a degraded landscape and then
watching the prairie thrive, but constructing a species community and an
environment for it that must remain on intensive life support, with constant
intervention, for it to survive at all, as long as the climate remains
unsuitable to it. The <ST1:PLACE w:st="on">Willamette</ST1:PLACE> prairie
remnants can’t be considered native; the only criteria they meet is that they
were here in small patches when botanists first catalogued them. But so were
dandelions. Botanists knew dandelions weren’t native, but the didn’t know that
the prairies were human created, so the prairies were catalogued as native.
Prairies in the Northwest haven’t been indigenous for 4000 years.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>We love the local prairies and I firmly believe in the
efforts to preserve them. But I want us to be clear that we are restoring to an
idea. We are restoring because we want these things here, and not because there
is a master blueprint that says they are the right ecosystem for the place.
Ecosystems exist because current conditions favor those particular assemblages.
Change the conditions, and the ecosystems will, absolutely, change. Both the
climate and humans have changed the conditions plenty. Environmental change is
the driving force behind shifting species makeup. With plants and most animal
species, no evil species showed up and through sheer cussedness, killed off the
locals. Instead, the conditions changed</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>The very concept of wild land, for most Americans, is founded
on a misunderstanding: a very brief ecological moment during which a
once-managed ecosystem was at the height of its degradation due to loss of its
keystone species. The dark and tangled primeval forests, written about by
Thoreau and Emerson, are simply the declining remnants of open and spacious
Eastern food forests, turned to thicket after a century or two of neglect. But
this idea of wilderness is deep in our mythology, national imagery, and
consciousness.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Let’s look at some of the causes of species change. First:
terminology. The word “invasive” is loaded. We hate invaders. The term also
places focus solely on the incoming species, yet the ability of a species to
survive is due to interactions with the biological and physical environment. So
I prefer a more neutral, and I think, ecological more correct and descriptive
term, such as opportunistic. Kudzu is not much of a problem in its native
habitat, but it will take advantage of opportunities.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>What creates those opportunities for species shifts? Intact
ecosystems are notoriously hard to invade. We know this because, for example,
seed dispersal rates are truly astounding.. Birds are a major dispersal agent.
They can carry seeds from multiple plant species in their gut, stuck to their
feathers, and in mud on their feet. So picture billions and billions of birds,
for 60 million years or so, traveling tens to thousands of miles, seeds dropping
off of them every wing-beat of the way. Add to that bats, which are actually
more effective at seed dispersal, per bat, than birds. Plus land-animal
dispersals, not as far-ranging as birds but bringing much larger seed loads via
droppings and fur. Include water-rafted trees and other plants, wind-dispersed
species, and more.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>This gives a picture of the whole planet crisscrossed with
billions of birds and animals for millions of years, seeds and spores going
everywhere, eggs being carried to new environments, dispersal, dispersal,
dispersal! So why isn’t the whole planet a weedy thicket? Because the mere
arrival of a new species, even in large numbers, is not what causes a successful
colonization. Ecosystems are very hard to invade, and several conditions must be
present for that to happen.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>A major reason for ecosystems being tough to invade is that
nearly all the resources in undisturbed ecosystems are being exploited. Nearly
every niche is filled, every nutrient flow is being consumed, almost every
opportunity is taken. Two major changes make ecosystems invasible: disturbance,
and the appearance of new resources. Take disturbance. Perennially disturbed
places, like riparian zones, are sensitive to opportunistic species. So is
farmland, or developed areas, or anywhere than humans or nature cause
disturbance. It drives me nuts when I read that “species X” has destroyed 50,000
acres of habitat. When you do a little digging you find that, no, that area was
farmed, or new roads cut, or logged, or polluted, or otherwise disturbed, and
then the new species moved in.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>For example, one poster child of invasion biologists is the
brown tree snake, blamed for invading <ST1:PLACE w:st="on">Guam</ST1:PLACE> and
killing off several species of birds. The untold story is that for decades the
US Navy used over half of the island as a bombing range, leaving most of it
unfit for life. Much of what remained was crowded by displaced people, and
developed by the military, and thus turned into poor and disturbed habitat. The
tree snake just cleaned up the struggling remnants that were already in serious
decline.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Stop the disturbance, and you’ll almost always eliminate or
reduce the effect of the new species. Land I lived on was clear-cut in the early
1970s and not replanted with fir until the 1980s, and was covered with patches
of Himalayan blackberry and Scot’s broom when I arrived in the early 1990s. By
the late 1990s, both species were gone from most places and nearly dead
everywhere else, because the trees had grown back and shaded them out. The
problem is disturbance, not that a species pushes out others because it’s tough
or mean.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>This suggests that we need to take care of naturally
disturbed areas like riverbanks, since most of the species we’ve labeled as
problematical thrive on disturbance. Even in these riparian zones, though,
conditions are altered from what they once were because of the loss of the
beaver and from damming. Thus nature is just trying to deal with our changes as
best as she can, and she’ll use whatever resources she can find. A return to the
former, natural disturbance regime may allow the once-present vegetation to
return, if that is our choice for that land,</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>The second cause of successful invasion is the appearance of
new resources. Often the new resources that that allow an otherwise intact
ecosystem to be colonized are pollution and fertilizer runoff. For example, a
number of aquatic opportunists, such as purple loosestrife, thrive in more
polluted and higher-nutrient environments than the plants they replace. Many
species that evolved in clean water are harmed by pollutants. Loosestrife,
though, has high rates of nutrient uptake, and this trait allows it to
out-compete many other species in polluted water.. But in permaculture, we say
that that every problem carries within it the seeds of its own solution. And so
loosestrife can be used in constructed wetlands and in natural environments to
clean nutrient-rich water. They are an indicator of a problem, a response to it,
and nature’s way of solving a problem, not the problem itself. If you really
hate loosestrife and want it to go away, clean up the water. Without doing that,
you’ll be flailing away at the problem forever. Spraying and yanking is not an
effective strategy to remove unwanted species. Nature is far more patient and
persistent, and has a bigger budget, than we do. To remove an unwanted species,
change the conditions that made it more favored than the desired vegetation.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Unwanted species generally arrive because humans have changed
the environment to make conditions more favorable for the new species. And when
we “restore” landscapes, or more often, introduce a set of species that we have
decided are the ones we want to see there, we are altering the landscape to suit
our idea of what should be there, not to match some divine plan. These two
understandings burden us with a huge responsibility to make intelligent choices,
but more importantly, to recognize that we are often arbitrarily making a choice
based on our own preferences, not because there is only one right choice for a
landscape, When we put resources into landscape management, however, we direct
the shape of that landscape toward only one choice. That’s the best we can do.
Thus I’d like to see us be less dogmatic in the way we cling to those
choices.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Unfortunately, dogma is present on all sides. Friends of mine
approached the <ST1:CITY w:st="on"><ST1:PLACE
w:st="on">Portland</ST1:PLACE></ST1:CITY> city government with a plan to create
some edible plant corridors along Springwater Trail, a 40-mile bicycle and
pedestrian loop around the city. Their idea was for bikers and pedestrians to be
able to snack on berries and fruit. The city official in charge said, “Nope, we
have a natives-only policy on the trail.” The trail is a paved pathway that goes
through industrial areas and along backyards, road right-of-ways, and scrubby
vacant lots. It probably goes through a dozen or more different environments,
based on soil, water, sunlight, and all the other factors that determine what
plant communities will grow there. But the policy is natives only. Wouldn’t it
make sense for the primary species that will be using that trail to have a
habitat that suits that species’ needs for food and comfort, particularly since
it’s in a busy urban area? But instead the landscaping is to be driven by an
idea, by dogma. I totally support the idea of having natives-only areas on the
trail. But let’s allow the new landscaping to serve those that it’s being built
for, too.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>I began this with corn and soybeans. One of my favorite
snarky questions for natives-only people is: “What did you eat for breakfast?” I
ask that because it is our choices that determine how much of our landscape is
going to be consumed by non-native species.. I didn’t eat camas cakes with
pink-flowering currant syrup this morning, and I’ll bet you didn’t eat any local
plants either. Of course, I’d rather see someone growing indigenous species in
their yard rather than having a sterile, resource gobbling lawn. But my
<ST1:CITY w:st="on"><ST1:PLACE w:st="on">Portland</ST1:PLACE></ST1:CITY> yard is
not, in my or several other lifetimes, going to be part of a natural ecosystem.
I might be able to cultivate some endangered native species in an attempt to
pull a rare plant back from extinction. That’s one good reason I can see for
growing indigenous plants in my yard. But the most frequent native plants I see
grown in yards are salal, Oregon grape, and others that are in no danger of
extinction and don’t, to my knowledge, support specialist species dependent only
upon them. And since much of my yard is watered, it is inappropriate for me to
grow natives that are adapted to our dry summers. It’s always stuck me as
bizarre to see Northwest natives being irrigated.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>But even more than indigenous plants, I’d rather see someone
providing for some of their own needs from their yard. When we eat a bowl of
cornflakes for breakfast, or oatmeal, or store-bought eggs, we are commissioning
with our dollars the conversion of wild land into monoculture farms. I’ll bet
that a large percentage people reading this buy local food, shop organic, and so
forth. But the farms growing that food are almost all moncultures, and out of
the urban matrix. In other words, it is farmland that, if consumption decreased,
has a far better chance of being restored to a functioning ecosystem than a home
lot. If I grow some of my own food, that means that somewhere out in the
country, a farmer won’t have to plow so close to the riverbank, or could let
some of that back field go wild. That land has a far better chance of
functioning as an ecosystem than my yard will. Oh, I have visions of how city
and suburban landscapes could be functional ecosystems, but that’s another
subject.. My point is, we need to be putting money and energy into growing
indigenous species where they will do the most good, where they can truly
contribute to ecosystems and their functions. Much of our efforts in eliminating
exotics is a complete waste of resources at best, and at worst is a terrible use
of poisons to destroy a hybrid habitat whose function we don’t yet grasp. Let’s
be honest at what we are restoring to: an idea of what belongs in a place. If we
want to get rid of an invasive exotic, let’s get rid of some monocultured corn,
and let a bit of farmland return to being a real ecosystem.</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>Copyright 2007 by Toby Hemenway</P>
<P class=MsoNormal><O:P></O:P></P>
<P class=MsoNormal>(presented at the Native Plants and Permaculture Conference,
<ST1:PLACENAME w:st="on">Lost</ST1:PLACENAME> <ST1:PLACETYPE
w:st="on">Valley</ST1:PLACETYPE> <ST1:PLACENAME
w:st="on">Educational</ST1:PLACENAME> <ST1:PLACETYPE
w:st="on">Center</ST1:PLACETYPE>, <ST1:PLACE w:st="on"><ST1:CITY
w:st="on">Dexter</ST1:CITY>, <ST1:STATE
w:st="on">Oregon</ST1:STATE></ST1:PLACE>, in May 2007.)</P><BR>
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