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Illinois Wetland Ecosystems Prairie Pothole Wetlands Wetland Plant Types Prairie Wetland Plant Communities Wet meadows, composed of sedges, forbs, and grasses Mudflat annual communities made up of smartweeds, grasses
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Prairie Wetland Plant Communities • Wet meadows, composed of sedges, forbs, and grasses • Mudflat annual communities made up of smartweeds, grasses • Emergent communities (plants with roots growing underwater or in water logged soil, while the rest of plant emerges from water into air) - made up of cattails, bulrushes, reeds, bur reeds • Floating leaved communities which feature species such as water-lilies • Free-floating communities made up of duckweeds and watermeals • Submersed communities made up of pondweeds, coontails, naiads, and bladderworts
Dry Marsh • Dry marsh (also called drawdown phase) - this develops during years of low water caused by below-normal precipitation when all or a large part of the marsh may be nearly dry or at least has no standing water • Mudflat annuals and emergent species are the dominant plants
Regenerating Marsh • Regenerating marsh - when normal precipitation resumes, standing water returns, allowing germination of submersed and free-floating plants • The regenerating marsh is characterized by an extensive cover of emergent species with submersed as an understorey
Degenerating Marsh • Degenerating marsh - during this phase there is a decline in the populations of emergents due to a variety of interrelated factors which may include anoxia, damage from insects, disease and muskrats • This stage has anywhere from a 25:75 to 75:25 ratio of emergent vegetation to open water and this is the phase with greatest wildlife diversity and density
Lake Marsh • Lake marsh or "eat out" phase is dominated by submerged plants like coontails, naiads, pondweeds, bladderworts; and floating aquatic plants like duckweed - the few remaining emergent plants may nearly disappear • the lake marsh phase continues until the next drought lowers the water level (which usually occurs on a 5 to 30 year cycle) and returns the marsh to the dry marsh state, starting the cycle over again
Stresses of Wetland Environments • Wetland environments are characterized by several environmental stresses that most organisms are ill equipped to handle - Aquatic organisms are not adapted to deal with the periodic drying out that occurs in many wetlands • Terrestrial organisms are stressed by long periods of flooding • Because of the shallow water, temperature extremes on the wetland surface are greater than normally experienced in aquatic environments
Stresses of Wetland Environments • But the most severe stress is probably the absence of oxygen in flooded wetland soils, which prevents organisms from respiring through normal metabolic pathways - in the absence of oxygen, the supply of nutrients available to plants is also modified and concentrations of certain elements (iron, sulfur) and organic compounds can reach toxic levels • In coastal wetlands, salt is an additional stress to which organisms must respond
Adaptations to Stress • Adaptations can be broadly classified as those that enable the organism to tolerate the stress and those that enable it to regulate the stress • Tolerators have functional modifications that enable them to survive, and often to function efficiently, in the presence of stress • Regulators actively avoid the stress or modify it to minimize its effects
