The Riverlands Migratory Bird Sanctuary includes 1200 acres of restored bottomland marsh and prairie and is managed by the USACE. Prior to the construction of the Melvin Price Locks and Dam, this 1200 acre section of land was in crop production. After the construction of the dam, water elevations increased and the croplands were infested with invasive plants such as Musk Thistle (Carduusnutans) (USACE, 1993). The USACE researched the historical vegetative cover near the Great Rivers Confluence and developed a management plan that would help reduce and control invasive species while reestablishing a plant community similar to what would have occurred prior to settlement--a mosaic of bottomland marsh and prairie.
Restoration began in the late 1980s with plantings of native warm-season grasses which tolerate the soils types found in the Sanctuary, including Big Bluestem (Andropogon gerardii), Switchgrass (Panicum virgatum), Eastern Gamagrass (Tripsacum dactyloides), Indian Grass (Sorghastrum nutans), and Prairie Cordgrass (Spartina pectinata). Mesic prairie plantings occurred in areas that had well-drained soils; while, wet prairie plantings occurred in areas that had poorly-drained soils.
During the summer of 2013, the Melvin Price Locks and Dam gauge witnessed the fifth highest water elevation on record. The levee which separates the restored marsh and prairie area from the river channel was overtopped and a nearby levee breached. As a result, the bottomland prairie at Riverlands was inundated with floodwaters for several weeks. As water levels started to recede, large patches of prairie were overgrown with Giant Ragweed (Ambrosia trifida), Trumpet Creeper (Campsis radicans), and Johnson Grass (Sorghum halepense) that shaded out prairie grasses and forbs.
After the flood it was evident that adjustments to the management plan were necessary to maintain diversity of the prairie, and control invasive species (both introduced and aggressive natives) that have colonized in the Sanctuary after flood events.The $20,000 in support from MoBCI allowed us to work with Shaw Nature Reserve personnel and USACE to work on a long-term sustainable plan for the Riverlands prairie and apply this management. As a result of this coordination, a more intensive mowing regime at a height of 8-12 in. in problem areas was implemented in combination with the existing prescribed burn regime (~ every 3 years). These actions aim to better control the dominance of prairie grasses as well as control encroaching woody shrub and tree species on site. Herbicide is used to help manage problematic species that cannot be controlled solely with fire and mowing.
In addition to management strategies to control aggressive species, partners are working together to gather seeds from desirable species that are representative of the conditions found at Riverlands but have not established yet. The seeds are cleaned, processed, and then broadcast in specific management areas to increase local forb diversity. Audubon aims to work with project partners to help support the prairie rehabilitation project, coordinate volunteers during seed collection events, and assist with seed management.