Cattail tubers and bark from smallish hardwood trees that they embed underwater for winter food. Hidden affect of that is the cattail is not particularly good habitat or food source for waterfowl so then you have one more item pushing down on waterfowl populations.

That was my thought too. Nothing in an ecosystem exists in isolation. Change a single variable, especially a dramatic change like going from 8% to 60% on a single variable, and there will be ripple effects throughout the local ecosystem. The Law of Unintended Consequences is one of those unchangeable, eternal laws that when you forget them, the Gods of the Copybook Headings limp up to explain it once more*.

* https://www.kiplingsociety.co.uk/poem/poems_copybook.htm for anyone who doesn't recognize the reference in that last sentence. Most people will, I hope, but there's always the lucky 10,000. (https://xkcd.com/1053/)