Drawing shows how wetlands support a rich food web, from microscopic algae and submerged vascular plants to great blue heron and otters.

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Wetland Functions and Values

Wetlands can be thought of as "biological supermarkets." They produce great quantities of food that attract many animal species. The complex, dynamic feeding relationships among the organisms inhabiting wetland environments are referred to as food webs. The combination of shallow water, high levels of inorganic nutrients, and high rates of primary productivity (the synthesis of new plant biomass through photosynthesis) in many wetlands is ideal for the development of organisms that form the base of the food web —for example, many species of insects, mollusks, and crustaceans. Some animals consume the above-ground live vegetation (herbivore-carnivore food web); others utilize the dead plant leaves and stems, which break down in the water to form small, nutrient-enriched particles of organic material called detritus.

As the plant material continues to break down into smaller and smaller particles, it becomes increasingly enriched (nutritious) due to bacterial, fungal and protozoan activity. This enriched proteinaceous material, including the various microbes that colonize it, feeds many small aquatic invertebrates and small fish. Many of these invertebrates and fish then serve as food for larger predatory amphibians, reptiles, fish, birds, and mammals. Numerous species of birds and mammals rely on wetlands for food, water, and shelter, especially while migrating and breeding.


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Section 2 of 12