When a wetland dries out and bottom sediments are exposed to air, wonderful things happen. The loose organic soup that has accumulated over time finally has a chance to consolidate and firm up. Oxygen reinvigorates decomposition and fuels a rapid breakdown of organic matter. Nutrients are released, having the same effect on vegetation as fertilizing a lawn. Plant seeds that have been dormant in the soil have a chance to germinate and grow. The clock on the natural aging process is turned back, and the wetland is rejuvenated.
Typically, more dynamic wetlands are more productive. At one extreme are saltwater marshes, which experience daily ebb and flow of tides. On the other end of the spectrum, some wetlands may go for years without experiencing a dry phase and consequently decline in productivity.
In the Prairie Pothole Region, wetlands typically have shallow basins with broad, gently sloping edges. Consequently, small changes in water levels can affect a large portion of the flooded area of prairie wetlands, and some degree of drying usually takes place each year as water levels decline, typically in late summer and early fall. During severe droughts, which have occured on the prairies every two to three decades during the last century, wetlands in the pothole country go dry on a massive scale. Whether short-term and local or long-term and extended, drying periods are essential to rejuvenate wetland basins.
When wet conditions return, waterfowl capitalize on the abundant, highly productive habitat. This dynamic cycle is why prairie potholes are among the most productive waterfowl breeding habitats in North America.