Managing Wetlands: Invertebrates in Wetlands

Invertebrates play a vital role in all wetland communities. They provide an important component in the food web, recycle nutrients and contribute to the breakdown of organic matter. Waterfowl, shorebirds and herons select invertebrate prey during high-protein and calcium-demand periods, such as egg-laying time. Several fish species feed almost entirely on aquatic insects, and raccoons often feed on crayfish during drying conditions in wetlands. True aquatic invertebrate organisms include crayfish, dragon flies, damselflies, mayflies, midges, water-boatmen and snails. Organisms found in moist, exposed soils include ground beetles, pirate spiders and diptera (fly) species.

The amount of invertebrates in wetland systems can vary depending on management practices. Moist-soil management produces excellent habitat for numerous mammals and birds as well as for many species of invertebrates. In this management technique, drawdown and refolding releases nutrients from the soil, which encourages robust stands of emergent vegetation, important as substrata for dynamic populations of invertebrates. Early summer drawdowns concentrate invertebrates, resulting in optimum feeding habitat for young waterfowl, shorebirds and herons.

Image Right: Dragonflies and other invertebrates play important roles in wetland habitats.

Permanently flooded wetlands also provide important invertebrate habitat when water clarity allows aquatic plant growth. Submergent and emergent aquatic plants provide places for invertebrates to hide, cling to, graze and lay eggs. Although the populations of invertebrates supported by these wetlands are not as dynamic as those produced during moist-soil management practices, they do provide habitat for many invertebrates important to a balanced wetland community.

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