DU Podcast Transcript: Ep. 22 – Two Sides of a Drought

Drought can be just as beneficial as it can be harmful for waterfowl habitat

© Michael Furtman

Clay Baird: Welcome to the Ducks Unlimited podcast, the only podcast about all things waterfowl from hunting insights to science-based discussions about ducks, geese, and issues affecting waterfowl and wetlands conservation in North America. We bring the resource to you, the DU podcast with your host, Chris Jennings.

Chris Jennings: Today I've got Dr. Mike Brasher in the studio here with me. And today, we're going to talk about drought. And when you hear people talk about drought, people start kind of cringing a little bit like, "Oh no drought, drought across the prairies." And one thing that brought this up is, we've already done the shows for the waterfowl survey. We've discussed, pond counts, how they are down. And there  is drought throughout portions of the Canadian prairies this year. And on the flip side of that, you've got South Dakota has got more water right now than they know what to do with. But what I wanted you to come on and discuss is the benefits of drought and how that impacts, it's all a cycle. And so what are the benefits of a drought on a wetland?

Mike Brasher: Yeah. I think an important thing to take away from this is to really realize that it is, as you mentioned, a cycle, these droughts come and go.

Chris Jennings: Mm-hmm (affirmative).

Mike Brasher: And that's actually not always a bad thing. We need droughts occasionally to recapture the productivity of these wetlands. So you mentioned that South Dakota has more water right now than it may have ever had.

Chris Jennings: Oh yeah.

Mike Brasher: And while that's great right now, we don't want that. The ideal situation would not be to keep that in the current situation for three or four years and because what happens is when those basins are wet, and we'll have to get a little bit technical here, what happens is, in the presence of that water, there's not a lot of oxygen getting to some of the organic material in that wetland. So longer the water stays on, the more that wetland and all the vegetation and animals and all the organic material in that system, it exists in the absence of oxygen. And so the consequence of the absence of oxygen is that organic material, those plants, when they die and plants are made up of various nutrients and carbon and all that, and that's sort of the base of the food chain is those nutrients. Those nutrients are more tied up and in the absence of oxygen, they can't decomposed as readily. And so when that's tied up, it's not available for reuse by the food chain. And so what happens when you have drought or even just some periodic drying, doesn't have to be an intense drought, but you'd pull that when that water comes off, that dead vegetation, any other kind of organic material that's in that system gets exposed oxygen in the bacteria and the fungi, the key decomposers if you will, they really take off and they start converting that organic material back into its native nutrients. It's carbon, it's nitrogen, and those nutrients, which are then returned to usable forms by plants and other primary producers and the things that really fuel the food chain. So it's-

Chris Jennings: That's when the invertebrates come in.

Mike Brasher: That's right. That's right. And so then that feeds on up the food chain, so it's fundamentally drought or the drying of these wetlands. It's fundamentally necessary to allow the decomposition of the dead plants and any other organic material that they may be in there and return those to usable forms of nutrients. And then so that's fundamentally what's driving the idea of drought being a good thing.

Clay Baird: [ADVERTISEMENT] Be the first to know when ducks are on the move. Sign up for DU's waterfowl migration email alerts and receive ongoing in depth updates on the latest habitat conditions, weather changes and hunting reports for your flyway. Visit ducks.org/migration alerts.

Chris Jennings: Just a quick thought, how does this extend to the management of seasonal wetlands ... like someone managing a wetland? Is it the same process?

Mike Brasher: It's the exact same concept and if we're talking about sort of the annual management of wetlands for the production of food or the production of resources for waterfowl, it's the exact same concept. You have the water on there, let's say in fall and winter, and then you draw that water off in the spring, you're exposing that dead vegetation to oxygen, and you're allowing the bacteria, the fungi to decompose that vegetation at a faster rate and return it to the system on an annual basis. Otherwise, if you keep the water on there, again, you're going to create anaerobic conditions and then there are some species, some plant species that can proliferate in those kinds of anaerobic environments. And that type of wetland management is common in many places and it's very valuable in many places. And you can usually, depending on where you are, and a lot of this varies just based on climate and how long the growing season is, but you can get away with holding water on wetlands for one or for two or three years in many cases, and you'll be fine. You'll create some very diverse and very valuable hemi marsh conditions. You have the cattail, bull rush grow up, which are all valuable in themselves, submerged aquatic vegetation, whether it be pond weeds or any other kind of floating or submerged aquatics, which produce lots of good food. Those can be really, really valuable.

Chris Jennings: Which attracted a completely different type of new species of duck.

Mike Brasher: They do.

Chris Jennings: We're talking puddlers to divers ratio.

Mike Brasher: They do. And it's very much needed, very much needed. We need a diversity of wetland habitat types, let's be clear about that. We don't need everything to be drained in the summer.

Chris Jennings: Yeah.

Mike Brasher: Drawn down for this type of intensive management. We need a diversity of wetland habitats to support waterfowl and other species that benefit from wetlands. But yeah, it's fundamentally the same thing. It's the manner in which the presence of water and the length of time that the water is on a given area and how that affects that food chain and the plant communities and eventually those plant communities they'll lose their productivity.

Chris Jennings: Yeah. And so really what it sounds like is that just, it's a happy medium. You don't want to have water on it for too long. But you also don't want it to be dry for too long.

Mike Brasher: Well that's right.

Chris Jennings: What are some of the impacts of with it being dry for too long?

Mike Brasher: Well from a waterfowl perspective, there's no water there.

Chris Jennings: Makes sense.

Mike Brasher: It's not usable. It does not exist as usable a habitat if you will. It's not habitat. If there's not water on it, it's not producing food, you know? So that's the biggest consequence of it being dry for too long as it's no longer habitat for waterfowl or any other wetland dependent species.

Chris Jennings: Okay. Well cool. Well, hey Mike, I appreciate you coming on and I hope everyone learned a little bit about drought today and just hearing the word drought, it's not something to fear unless it's a very prolonged drought. But also on the flip side of that you've got your flooding, not a huge deal unless it's something that's prolonged as well. And what I think waterfowl managers are looking for here, for suitable habitat is just a happy medium.

Mike Brasher: I think that's right.

Chris Jennings: Cool. I appreciate it.

Clay Baird: Thank you for listening to this episode of the DU podcast. Be sure to rate, review, and subscribe to the show and visit www.ducks.org/dupodcast for resources based on today's topics, as well as access to more episodes. Opinions expressed by guests do not necessarily reflect those of Ducks Unlimited. Until next time, stay tuned to the ducks.