Areal Extent of Sediment Overburden in Restored Prairie Wetlands and the Impact on Recolonization by Aquatic Invertebrates and Hydrophytes in the United States Prairie Pothole Region.

Approach and Objectives; An Overview

NPWRC will provide information on basin morphometry and land-use history collected during the extensive survey of drained, restored, CRP, and pristine seasonal and semipermanent wetlands. Sediment cores will be collected from a subsample of restored, CRP, and pristine wetlands. I will determine sediment accumulation in wetlands by examination of recalcitrant invertebrate remains (e.g., ostracod shells); the depth at which recalcitrant remains are no longer detected will define the maximum wetland depth since glaciation. A subset of cores will be analyzed for ²¹⁰Pb dating signatures to separate overburdens into historic and recent accumulations. This information will be analyzed to examine the spatial patterns of sedimentation in the PPR region and relate observed patterns to land-use and basin morphometry. I will perform a series of controlled aquaria and greenhouse experiments to examine the influence of sediment overburden on the recovery potential of hydrophytes and aquatic invertebrates in restored wetlands. Wetland soil samples will be obtained from drained, restored, CRP, and pristine wetlands sampled extensively by NPWRC. Wetland soils will be subjected to greenhouse and aquarium experiments to assess differences in seed bank and invertebrate egg bank composition among wetland categories. Then for wetlands with known sediment overburdens, I will examine the relationship between sediment accumulations and seed and invertebrate egg bank composition. Additionally, for both the greenhouse and aquarium experiments, I will include a set of treatments consisting of pristine wetland soils with an upper layer of upland soil of varying thickness. This information will be used to determine the effects of sediment overburdens on emergence of invertebrates and hydrophytes. The specific objectives of my study are:

1. Examine the influence of land-use on sediment overburdens in restored, CRP, and pristine wetlands in the United States PPR.
Examine invertebrate egg bank composition among drained, restored, CRP, and pristine wetlands and the influence of sediment overburden on recolonization potential of aquatic invertebrates in restored wetlands in the United States PPR.
Examine seed bank composition among drained, restored, CRP, and pristine wetlands and the influence of sediment overburden on recolonization potential of hydrophytes in restored wetlands in the United States PPR.

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