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The North American Invasives that nobody wants to talk about

 
Gilbert Fritz
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Invasive plants: a contentious topic.

But there are two invasive species that are not talked about much.

The two invasive species which have perhaps changed North America more then any others, (after humans of various tribes), are the honey bee and the earthworm.

Earthworms change the structure, ecology, and possibly chemistry of the soil, which affects the water cycle, nitrogen, mineral, and carbon cycles, and most importantly what kinds of plant will thrive in that soil. It makes sense that Asian and European earthworms would make the soil more suitable for . . Asian and European (invasive) plants. (Including most of our crop and garden species, thus the benefits of Earthworms in our gardens. )

honey bees are fundamentally different then the native bees that came before the European invasion. Honey bees tend to forage whatever is most abundantly flowering in the area at a time, to maximize the amount of pollen and nectar brought back to support a large hive. (Thus giving mono cultures an edge; that is why large orchards ship in honeybees to pollinate their mono cultures.) Native bees were often specialists, focusing on one species or genera, or they were generalists, pollinating whatever was closest. They didn't have to store such massive amounts of food as the honeybees do, so they operated in a different manner. It makes sense that Asian and European Honey bees would favor the reproduction of . . . Asian and European (invasive) plants.

So, I have the solution! Speed up colony collapse in bees, pay Monsanto to cook up a special vermicide and spray it on every square foot of land- and boom, the invasive plants are no longer such a problem. Wait, maybe that is not such a great idea.

What do you all think about this?
 
Joseph Lofthouse
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I think that earthworms only died out of some areas because those areas were covered with glaciers. South of the glaciers they continued to thrive. Once the glaciers receded, the earthworms started crawling northward, and being carried by rivers, and by birds, and in soil on animal feet. Earthworms are destined to recolonize their ancestral home. To me, a worm is a worm regardless of where it was living 500 years ago.

 
Gilbert Fritz
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Hello Joseph,

Yes, that is kind of how I feel. But I'm just pointing some things out; invasive plants is a WAY more complex subject them most people imagine.

From what I've heard, most Colorado worms are true exotics from Europe; native worms, while they do exist south of the ice line, had a different ecology and are rather rare, but I'm still trying to get a definite answer on that.
 
Gilbert Fritz
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Ongoing reading; looks like most of the larger and more common worm species are exotics, especially (surprise, surprise) in disturbed ground.
 
taylor burt
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Gilbert, I am totally with you on these two. Living in the maple-producing region of the northeast, earthworms pose a particular threat to the self propagation of maple trees. In forests with earthworm infestations, they consume all the litter on the forest floor, making it impossible for the maple seeds to germinate. It is a remarkable sight to see...entire forest floors void of any leaf litter - a rare sight here in New England, but increasingly common due to the earthworm.

As for European honeybees, they are overrated pollinators that, as you mention, are not nearly as good at promoting diversity and pollinating in general. I think we should be promoting beneficial insect plantings and habitat, like "bug motels" and other such things, thereby promoting a diversity of pollinating insects.
 
Gilbert Fritz
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I'm guessing that, once the earthworms have removed all the litter, their numbers should crash, and come into a sort of balance; but I'm not speaking from knowledge here, just opinion. It just seems to make sense.
 
Jesus Martinez
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taylor burt wrote:Gilbert, I am totally with you on these two. Living in the maple-producing region of the northeast, earthworms pose a particular threat to the self propagation of maple trees. In forests with earthworm infestations, they consume all the litter on the forest floor, making it impossible for the maple seeds to germinate. It is a remarkable sight to see...entire forest floors void of any leaf litter - a rare sight here in New England, but increasingly common due to the earthworm.

As for European honeybees, they are overrated pollinators that, as you mention, are not nearly as good at promoting diversity and pollinating in general. I think we should be promoting beneficial insect plantings and habitat, like "bug motels" and other such things, thereby promoting a diversity of pollinating insects.


I live in the pnw. We have lots of earthworms and maples. In fact, this spring the newly sprouted maple trees came in thick as grass....
 
Gilbert Fritz
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I guess the point I'm trying to make is that humans spread around the earth bring a certain "guild" of plants and animals, the "grand alliance." European's guild contained earthworms, honeybees, rats, mice, poison hemlock, apple trees, wheat, many weeds, horses, dogs, and chickens. Polynesian's contained bananas, taro, dogs, and chickens. (I'm leaving out a lot of things from both groups.) Native Americans seem to have used groundnut and sunchoke tubers across North America; they may have spread them as part of their alliance.

So, it may be good or it may be bad that we and our guild are here to stay. (After all, many of our guild members are not popular with us.)

But I'm not sure how to undo the damage.

Invasive plants are mostly members of the grand alliance, or are trying to join. And we would have to remove ourselves and the whole alliance to get rid of them. But that's the hard part. We would leave, but at least some alliance members would stay behind.
 
Jesus Martinez
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I think Paul summed thus whole concept up very nicely. There are a lot of people saying we need to get rid of invasives and eat natives, but nobody subsiting on pine needles and acorns.
 
taylor burt
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Gilbert, yes, it seems that the worst infestations are self-regulating, and in the grand scheme of things not that big a deal, but still a significant effect on forest ecology.

Jesus, it is good to hear that your forests are unaffected by non-native earthworms. The great majority of our forests here are unaffected as well, which is a huge relief. I am not advocating for controlling the invasive earthworm population, but I do advocate for monitoring it, as problems can quickly progress with changing climate.

Here is a link to a paper published about the effects of earthworms entering a previously unaffected forest: http://conservancy.umn.edu/bitstream/handle/11299/175603/Frelich%20et%20al%202006.pdf?sequence=1&isAllowed=y

Here is an quote from the paper:

"Earthworms can contribute to a forest decline syndrome, and forest herbs in the genera Aralia, Botrychium, Osmorhiza, Trillium, Uvularia, and Viola are reduced in abundance during earthworm invasion. The degree of plant recovery after invasion varies greatly among sites and depends on complex interactions with soil processes and herbivores. These changes are likely to alter competitive relationships among plant species, possibly facilitating invasion of exotic plant species such as Rhamnus cathartica into North American forests, leading to as yet unknown changes in successional trajectory."
 
David Livingston
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In the UK native earthworms are themselves under threat by a carniverous worm from New Zealand

David
 
Joseph Lofthouse
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Gilbert Fritz wrote:But I'm not sure how to undo the damage.


I wonder how we would be able to discern that damage is being done? It's easy enough to observe change? But by what criteria can one determine that change = damage?

 
Gilbert Fritz
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Correct; it is hard. I guess the only way to tell would be to keep two parallel ecosystems and observe them for 500 years; one where the invasive plants and animals were religiously chopped out, the other where things went their own way. At the end of the 500 years, we could observe levels of biodiversity, biomass, stability, water retention and purification, and soil erosion, and use these to determine which was healthier. Even then it might be difficult.

So the upshot is that I'm opposed to digging out invasive plants just because they are non-native. It seems like an exercise in futility unless we are willing and able to remove the whole human guild from the area. (Of course, I might dig out Russian Olive because it is in my way and I'd rather have something else, just as I would remove an annoying native plant.)

On the other hand, if there are any areas where the human guild is not yet present, maybe we should think twice about introducing it; once the salt is in the soup, it is hard to get out again!
 
Joseph Lofthouse
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One of the species that is new to my area is "Eurasian Collared Dove". I have loved watching how it is part of the human guild. I pretty much only observe it in close association with humans. I almost never see it in the wildlands.

 
David Livingston
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Wow I am impressed I did not know it had reached the USA ! Calling it european is a bit of a misnomer as it only spread to europe in the 20th century as far as I am aware it origionated in asia . Got to the UK about 1950 and Iceland in the 1960s. Tastes similar to other doves ...er so I am told

David
 
Gilbert Fritz
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Joseph,

I've loved the idea of the "grand alliance" ever since reading Carol Deppe. It makes perfect sense.

So we can't go attacking invasive plants; they are part of our community. Humans are an "invasive" species in North America. And while it is currently fashionable to claim that European humans are invasive, the same must be said for the Native Americans/ Asians who came before us. I'm sure they brought some "guild" member with them, or at least acquired them once here and moved them around.

It is fascinating how fast Natives adopted European spices; horses, watermelons, fruit trees, sheep, etc. In many cases they acquired them through trade BEFORE actual European contact. The first Europeans down the Mississippi found watermelon growing.
 
Jay Angler
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One of the things we need to do first is accept that the environment the Europeans took over in North America was not "pristine wilderness", but a human/predator managed ecosystem. The humans managed it with fire and by encouraging preferred plants and the predators by culling the weak, sick and old. We've messed that up in a big way. I have heard that deer pressure on what is called "Carolinian forest" is preventing the forest from maintaining itself, but the deer used to be controlled by man and predators. I've had little luck locally in convincing the local pro-deer supporters that if we aren't going to allow the cougars to control them, we need to fill the cougar's niche!

One of the most important things that permaculturally-minded humans can do is to manage wild areas on their land in ways that provide and encourage biodiversity of plants and animals. A small pond the previous owner built grows duckweed that my ducks adore but I don't let them any where near it in the early spring because the tree frogs lay their spawn there. I can't control the wild ducks other than by disturbing them, but I'm trying to do my bit to help out one endangered species and hoping that the ripple effect will travel. If we all look for ways to do small things like that, hopefully it will add up to something larger.
 
Tyler Ludens
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Jay Angler wrote:the deer used to be controlled by man and predators. I've had little luck locally in convincing the local pro-deer supporters that if we aren't going to allow the cougars to control them, we need to fill the cougar's niche!


This is one of my pet peeves. We're over-run by deer killing all the young trees and nobody wants cougars around. Grrr!

We could use some extra-large cougars or possibly jaguars to help control the non-native Axis deer, who are especially destructive (but delicious).

 
Shawn Harper
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Tyler Ludens wrote:who are especially destructive (but delicious).


Sounds like the problem is the solution.
 
Jesus Martinez
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Something that I don't really see recognized is that the fossil record is full of the environment changing drastically even without the assistance of humans. We can go on and on about what we've done to change the environment, but the fact remains that it would have changed regardless of our meddling. Because of this, is it such a bad thing for us to try to mould it our liking?
 
Tyler Ludens
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Jesus Martinez wrote:Because of this, is it such a bad thing for us to try to mould it our liking?


It can backfire fairly horribly if we don't know what we're doing.

 
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