Cattail As Architect

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Anna (left) with Central Iowa cattails

Meet Anna.

Anna & I have been busy this summer conducting research in…you guessed it…wetlands. Specifically, we have surveyed several sites in central Iowa, collecting data on cattail growth form and habitat. The basic question we hope to answer is “how similar are the plants we find, to Broad-leaved cattail (T. latifolia), to Narrow-leaved cattail (T. angustifolia), or to their hybrid (T. x glauca)?” Other researchers are calling into question our past identification of the species, and recent work has suggested that whatever the species identity, growth form has important ecological consequences (especially after the above-ground parts die back and become litter). We aim to investigate what all this might mean. We’re also wondering if we can relate growth form—what I sometimes refer to as “plant architecture”— to interactions with the rest of the wetland.

Watch for future posts with findings from that research. I imagine this to be ongoing work, involving future collaborations with students and faculty colleagues. The questions seem important, since cattail is so common (and often dominant) in our wetlands. My 99wetland wanderings frequently bring me into contact with cattail, all over Iowa.

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A sea of cattails ring Finn Pond

A recent visit to Finn Pond in Greene County provided some inspiration for my cattail curiosity. There’s plenty of cattails on this approximately 20-acre (8-hectare) wetland. Such a large site feels rather like a sea, or perhaps more colorfully described as a cattail jungle? Towering over my head, and so dense I can see less than arm’s-length in front of me, the cattails feel like an impenetrable thicket. Wouldn’t a wall of cattail be an interesting and important ecological phenomenon? How would this habitat compare to shorter, more sparse, or more diverse, vegetation?

I encounter several animals in the cattails in just a short walk. I imagine the structural characteristics of cattail leaves would be of great significance to birds. At least, if I were building a suspended nest attached to cattail leaves, I’d consider whether they were rigid, or slippery, or tall, or…well, any of the specs of this construction material of the marsh. Then I stop and look closely at the cattail…

DSC_0404Snails glide on the cattails as they scrape food off the leaf surfaces. I was surprised to find them congregating on the flower spikes, high above the water..actually, up above my head in some cases! What they are doing up there I can’t say—leave your thought in the Comments section.

DSC_0410Almost certainly, dragonflies will be affected by cattail architecture. As larvae, they swim in the water around the cattails, and frequently crawl up a cattail stem when it’s time to molt their juvenile exoskeleton and emerge to fly away. Here at Finn Pond, I watched an adult Widow Skimmer (Libellula luctuosa) as it perched on cattail leaves between flights, glamorous in its bright “racing stripes” and skillful in flight.

Later, I recalled these animal sightings, and what I know about the processes at work in wetland ecosystems. Anna and I talked a lot about how things work in a “cattail marsh,” and how the plant architecture might be important. I’m encouraged by the intriguing ideas we discussed, and delighted to explore Iowa wetlands, learning side-by-side with my student-collaborator. And I invite you to read future blog posts, and learn right along with us!

Author: Paul Weihe

Associate Professor of Biology at Central College, traditional author (Textbook of Limnology, Cole & Weihe, 5th ed.; Waveland Press), and now...blogger!

9 thoughts on “Cattail As Architect”

  1. Hi, Paul:
    I think the snail is a terrestrial snail in the Succineidae. Iowa has several species in that group, some of which are normally found in wetlands. There are also aquatic snails that climb onto emergent vegetation, but I am pretty sure yours would be considered terrestrial.

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    1. I’m glad for that info, thanks! She’s pretty, for sure. I think the odonate web site suggested the species is found in all 99 counties?? Maybe could be a mascot 🙂

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      1. There are a few species that are found in all 99 counties including Anax junius and Ischnura verticalis off the top of my head. Which odonate website are you referring to? Iowa Odes or the Iowa Odonata FaceBook page? Iowa Odonata is my FaceBook page and I am an administrator for Iowa Odes and OdonataCentral.org (I think I still need to get back to Iowa Odonata and accept your member request). Have you ever looked at OdonataCentral.org? You can get lots of info from It without having to be a member

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  2. Thank you for your cattail research. I really appreciate the work you and Anna are doing, and I look forward to reading much more about it. I keep hearing different things (and different advice) re Iowa cattails. They are vital habitat, they are invasive and should be controlled, they are routinely reduced by muskrats, don’t count on muskrats to manage them, etc.

    And then there’s the 2010 story below, which is truly scary. I’m guessing the situation hasn’t improved in the last nine years.

    http://www.mnsu.edu/news/read/?id=1283177298&paper=topstories

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    1. Hi Cindy! Thanks as always for your comments. I’m hoping we’ll have more answers and…make the best of the situation. Stay tuned as they say. Regarding that story…it all reads true to me. I have real respect for conservation professionals…making the best of their situation, too.

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