A Walk Through Wetlands
Upon entering a larger wetland, zones of upland and lowland grasses and marsh vegetation sometimes blend, blurring the boundaries of these habitats. Zones are areas within larger, more complex wetlands that possess characteristics similar to Type I, III, IV, and V wetlands. Distinctions between zones are subtle and always shifting or changing. This is what makes wetlands such diverse ecosystems. Water depth determines the diversity of plant species. In turn, plant species influence wildlife species.
Many wildlife species move between these wetland zones in order to meet their survival needs. For example, at the very edge of the wetland, where conditions may be dry to slightly moist, upland and lowland grasses dominate the area. Mallards, blue-winged teal, and pintails use these areas for nesting. However, feeding time brings them into the shallow waters of the wetland where invertebrates are numerous.
A little farther into the wetland and the water level and soil nutrients change, as do plant species. Plants that tolerate slightly more water such as arrowleaf and sedgegrass become established here. These areas provide a mix of feeding and cover for hens and their broods.
As you move ever deeper into the wetland, the water level rises. The water temperature may be slightly colder than in the shallow zones mentioned earlier. Very few grasses are growing here. Instead, cattails have become established in small groupings, creating a maze of cattails and open water. The cattails provide food and shelter for animals such as the muskrat. This vegetation also shelters duck broods and molting ducks and provides grebes and ruddy ducks with floating nesting areas.
There are some zones in which water is too deep for vegetation to become established. Where water quality is high, sago pondweed will dominate the open water.
Keep in mind that no two wetlands are alike and water levels vary year to year. Zones also change, depending on factors such as seasonal runoff, precipitation, and dry or drought conditions. In successive dry years, as well as wet, wetlands may undergo significant changes, resulting in a whole new "picture" or description of a wetland.