Approach
This approach addresses scenarios of wetlands becoming drier during the growing season. Less predictable depth, duration and seasonality of saturation and flooding can alter the germination and establishment of wetland plants and cause shifts in vegetation composition such as the encroachment of shrubs into herbaceous wetlands or the establishment of invasive species on exposed shorelines. Periodic lower water levels may also provide new opportunities to control undesirable vegetation or establish habitat for a different suite of species, while recognizing that habitats such as open mudflats are a natural phenomenon and can be very beneficial for annual plants and wildlife such as shorebirds. Techniques utilized in more engineered settings such as the development of unique seed mixes for wetland enhancement may also be useful in natural systems experiencing novel hydrologic changes. To a degree, managers can prepare for these changes and strive to maintain desired habitat and ecosystem functions and services.
Tactics
- Manage the transition of open wetlands to shrub-dominated wetlands by selectively controlling invasive shrubs.
- Plan for and take advantage of lower water levels by controlling invasive species and/or establishing desirable native species on newly exposed soil.
- In sites with open wetlands that are drying, inter-seed with wet meadow species tolerant of lower water levels (e.g., with wetland ratings of FACW and FAC) suitable for the region.
- In wetlands with distinct vegetative zones along a moisture gradient, plant species from the short-term saturation zone into the long-term saturation zone.
- Install small structures (e.g., one rock dams less than one foot in height) along headwater streams to increase soil saturation depth, extent and infiltration.
- Remove post-settlement alluvium from small incised floodplains and restore sedge meadow and wet prairie vegetation. Removing alluvium reduces depth to water table, increases residual soil moisture, improves water quality.
Strategy
Strategy Text
This strategy outlines approaches to facilitate ecosystem adjustments to cope with altered hydrology, water budget components (inputs, outputs, and storage of water) and water quality. Managers face both challenges and opportunities from a periodic lack of water (e.g., from drought and higher evaporation) as well as excess water (e.g., from larger precipitation events) that go beyond the historical range of variation in both magnitude and duration. Wetland managers will therefore need to adjust systems to maximize desirable ecosystem functions despite altered hydrology. This adjustment includes all components of wetland systems such as flood storage capacity, site nutrient cycling, as well as the habitat suitability of plants, wildlife, and aquatic species. Adjusting wetland ecosystems to climate changes applies equally to natural areas, as it does to wetland creations and enhancements, and existing hydrologically managed systems (e.g., lakes, impoundments, and rivers regulated by dams and other hard infrastructure). Proactive consideration of hydrologic change can help managers reduce future risks and take advantage of opportunities to sustain hydrologic functions into the future.