Re: [MidValleyNature:6222] Abridged summary of mid-valley-nature@googlegroups.com - 1 update in 1 topic

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Marge Popp

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Oct 13, 2021, 10:58:43 AM10/13/21
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I took a walk with a friend to Talking Waters on Monday. The ponds are choked with reeds...especially cattails.  We had walked here often over the past couple of years and couldn't recall seeing anything like this.  I remember Lisa talking about the invasive nature of cattails on other hikes but this seemed to happen so fast and be so prolific. 
Are there plans to eradicate the cattails? I don't even see how it would be possible; they are so thick and have overtaken the entire shore area.
Marge Popp

On Tue, Oct 12, 2021 at 10:41 PM <mid-vall...@googlegroups.com> wrote:
Lisa Millbank <millba...@gmail.com>: Oct 12 09:34PM -0700

We were walking last night in Village Green Park by the railroad tracks,
and heard a critter scuffling around in the weeds and blackberries. Don
turned his headlamp on and we could see a chunky ...more
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Lisa Millbank

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Oct 13, 2021, 1:12:21 PM10/13/21
to Marge Popp, Mid-Valley Nature
Since cattails are native plants that are generally encouraged in wetlands, I'm sure I haven't directly called them invasive, but I probably wasn't clear enough about what I meant when I said they could spread very quickly.  Sometimes I may not be careful enough about what I might by implying when I explain something during our field trips.  As far as I know, dense stands of cattails are beneficial for rails, Red-winged Blackbirds, Marsh Wrens, Green Herons, Muskrats and other wildlife. In some places, cattails get choked out by Reed Canary-Grass and seem to rebound when the grass is removed.  Talking Water Gardens also has a lot of bulrushes that form dense stands.

I wonder what accounts for the difference you've observed over time.  I know that Talking Water Gardens didn't end up functioning as well as it was intended to (to cool wastewater before discharge into the river), and maybe there has been a change in its maintenance.  Wetland plants like cattail were planted there as part of the water treatment and habitat enhancement.  I'm not sure how much open water they wanted to have vs. stands of wetland vegetation.  I had assumed that dense wetland plants were encouraged there, but maybe there's too much of a good thing!

Lisa


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Don Boucher

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Oct 13, 2021, 1:46:26 PM10/13/21
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Hi Marge, everyone,

I have a Golden Guide to Weeds that lists cattails but notes that cattail marshes are desirable for muskrat habitat. Cattails are only an issue in agricultural settings where irrigation ditches must be kept clear or may invade rice fields. Because of this, some people may spread the idea that cattails are weeds. Cattails are common so anyone who needs to remove them may do so without impacting their overall population. Theoretically, if there was a rare wetland plant that needed space to grow, cattails could be a factor, but I haven't heard anything about this in practice. Otherwise, cattails are native and beneficial wherever they can grow.

-Don

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Joel Geier

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Oct 13, 2021, 2:57:22 PM10/13/21
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I suppose the similarity of the Latin name for the genus (Typha) to Typhus might also help to give a "bad rep" to cattails!

For Talking Water Gardens, where there main purpose is to cool industrial wastewater to reduce thermal inputs to the Willamette River, I suppose cattails could also be beneficial both in providing some shade to the water, and also in soaking up any residual contaminants that make it through the water treatment system, before it goes into this pond system.

About rare wetland plants, from a watershed council tour of the facility a couple of years ago, I recall our guide telling us that the annual water cycle at TWG runs almost opposite the local natural cycle that rare wetland plants would be adapted to. They need to keep the ponds more full in summer (when stream temperatures in the Willamette are closer to critical thresholds for aquatic life), but then they draw them down in winter. They've actually found it challenging to find native plants that will thrive in those conditions.

For visitors, this can sometimes make it "hard to see the marsh for the cattails," though I think they sometimes mow them when they're able to draw water levels down all the way.

Joel


From: "Don Boucher" <donab...@gmail.com>
To: "Mid-Valley Nature" <mid-vall...@googlegroups.com>
Sent: Wednesday, October 13, 2021 10:43:12 AM
Subject: Re: [MidValleyNature:6224] Abridged summary of mid-vall...@googlegroups.com - 1 update in 1 topic

Lisa Millbank

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Oct 13, 2021, 3:20:52 PM10/13/21
to Joel Geier, Mid-Valley Nature
Yes, I think that's correct that one of the purposes of the plants is to absorb some of the nutrients in the water before discharge. We went on a public tour with the manager of the area shortly after it opened, and I think he said that the wastewater is fully treated before it goes to Talking Water Gardens, but that it is too warm from being used in industrial processes.  Like most wastewater, it still has some nutrients like nitrogen in it.  So the plants were supposed to take up the nutrients and the water was supposed to cool as it made its way through the whole system.  The treated water would then not contribute as much to the excess nutrients in the river coming from agricultural and lawn runoff.

TWG has a huge amount of duckweed and water fern/mosquito fern (Azolla), and they're both are native and good at shading the water.  I learned recently that water fern is very good at fixing nitrogen from the air, like legumes do.  I thought that the water fern could be kind of counterproductive, because it may be releasing a lot of additional nitrogen into the water when it decays.  I don't know if that's really a problem or not, and maybe there's enough other vegetation to absorb that too.

Lisa

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Ann Werner

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Oct 13, 2021, 3:38:14 PM10/13/21
to Lisa Millbank, Joel Geier, Mid-Valley Nature
Well, of course there isn’t a simple answer - some concerns with cattails are they will choke out the open water, leaving little or no room for frog spawn or dragon/damselflies & they 
reduce plant diversity in a marsh/wetland.  Cattails have an impressive root network & are virtually impossible to remove once established. Perhaps there are water bodies where depth limits their expansion? 

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On Oct 13, 2021, at 3:20 PM, Lisa Millbank <millba...@gmail.com> wrote:


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