By David Brakhage
We’ve all heard the expression “no pain, no gain.” Usually it applies to spending time at the gym or putting in extra effort to reach a remote duck hunting spot. But the expression also applies to wetlands and their need to endure occasional drought to remain productive.
Wetlands are among nature’s most productive ecosystems, and much of that productivity can be attributed to their dynamic nature. Extended wet and dry cycles, where water levels fluctuate over time, are vital components of maintaining wetland productivity. This is true for all wetlands, but is especially important for the prairie potholes of the northern plains. This, in turn, makes drought important to breeding ducks. To understand why, let’s take a look at some basic wetland ecology.
Wetlands are defined by at least seasonal water, hydric soils, and aquatic plants. Plants are key features of all wetlands. They are a primary source of food and cover for ducks and other wildlife that depend on wetlands. As these plants grow and die, they deposit leaves, stems, and other material in wetland basins. This plant matter is attacked by decomposers (microbes and insects), and the leftover organic material gradually accumulates on the bottom of wetland basins. Nutrients get trapped in this “organic soup” where a lack of oxygen inhibits further decomposition.
Under these conditions, the productivity of wetlands gradually declines. Over time, the plant community shifts from annual species that produce an abundance of seeds to perennials like cattails. The bottom also becomes increasingly soft, making it difficult for plant roots to hold. As plant growth declines, open water increases, reducing habitat quality for waterfowl and other wildlife. Fortunately, water levels in most wetlands draw down naturally at some point, and this is where drought plays a beneficial role in rejuvenating wetlands.