Wetlands
Wetland
Before people attempted to tame the rivers with dams, channelization and dikes, water followed the path of least resistance through the floodplains. Its meanders often left ribbons of water disconnected from the main channels, forming oxbow lakes, sloughs and backwaters. This fringe of stagnant wetlands, periodically recharged by seasonal floods, offers some of the richest habitat in the state for both crops and wildlife.
As settlers drained the wetlands to grow corn and wheat, cities built protective levees and dredges straightened the rivers for commerce and travel, wetland creatures found less room to live. Humans also felt the burden of these "improvements," for they no longer had wetlands to naturally filter their water or to absorb high water levels. Recent devastating floods are the direct result of the lack of an overflow valve that wide floodplains provide.
Although much of our wetland acreage has been lost to development, the Conservation Department is purchasing abandoned floodplains and helping them revert to their natural condition. These restored wetlands, along with the few natural wetlands that remain, offer some of the best wildlife-viewing opportunities in Missouri.
Marsh Management
A biologist monitoring insect levels
Damselfly nymph
A biologist at Eagle Bluffs Conservation Area "sweeps" the marshes to monitor levels of insects. The aquatic stages of developing insects are the main diet for many fish, frogs and water birds. Dead and dying vegetation provides the food base for invertebrates.
The damselfly nymph is one of many aquatic insects found in marsh waters. Waterfowl use this protein-rich food source to fuel their northward migration and meet the energy demands of nesting.
Surveys & Inventories
Green tree frog
Decurrent False Aster
Blue heron
Green tree frogs are one of 23 species included in the Missouri toad and frog survey and are a signal of environmental health. Many scientists attribute recent declines in amphibian populations to increasing pesticide use and thinning of the protective ozone layer. Trained volunteers visit sites three times during the breeding season to monitor populations.
The endangered decurrent false aster grows in oxbow lakes and sloughs in the big river floodplains around St. Louis. The term "decurrent" describes the plant's leaves, which extend down the stem from the base of the leaf. Conversion of wetlands to agriculture, combined with an increase in herbicide use, has contributed to this species's decline.
Conservation Department ornithologists, with the help of protection agents, monitor the state's 250 great blue heron rookeries. Because the species is thriving, the yearly survey of nesting colonies has been scaled back to once every five years.
