Return of Floodplain Connectivity and Concurrent Macroinvertebrate Community Response Following Wetland Restoration in Western Kentucky

Author

Christiane M. Soldo Ms., Murray State UniversityFollow

Abstract

Wetlands improve the quality of our nation’s streams, rivers, and lakes, and they support a diverse assemblage of plant and animal species. The U.S. Department of Agriculture Natural Resources Conservation Service (USDA-NRCS) is responsible for administering the Wetland Reserve Program (WRP), a multi-billion-dollar effort to restore wetlands throughout the nation. Each year, WRP enrolls thousands of acres of private farmland into conservation easements with the goal of improving water quality and creating wildlife habitat. Hydrological modification structures, such as levee breaks, ditch plugs, or shallow water areas are constructed on easements to create wetlands by improving water retention and returning floodplain connectivity to adjacent rivers. The main objectives of my study were to assess the efficacy of these hydrological modifications and to quantify macroinvertebrate diversity, abundance, and secondary production on easements enrolled in WRP. My study sites included restoration easements of various ages as well as mature bottomland forests, which represent pre-disturbance “reference” wetlands, and low-quality, drained wetlands. A combination of pressure transducers, LiDAR, and drone imagery was used to determine wetland extent and hydroperiod on each easement. Macroinvertebrates were collected monthly from each wetland with stovepipe cores and dip-net sweeps. The results of my study indicate that hydrological modification structures allow easement wetlands to capture and retain floodwaters throughout the year. Insects accounted for 12.6% of the total abundance in degraded wetlands and increased to 26.5% in WRP easements and to 65.5% in reference wetlands. There was no statistical difference in annual production (g DM/m²), abundance, or biomass, diversity between wetland types. However, we found a wide range of annual production (850 to 7,746 mg DM/m²) and relative abundance of emergent taxa (<20% to >80%) among individual wetlands. Non-insect taxa were important to total biomass, and total Mollusk biomass decreased from 63% in degraded wetlands to 2.3% in reference wetlands. The frequency, intensity, and duration of inundation at each site were the primary variables influencing invertebrate community structure. Because new easements are permanently enrolled, there is tremendous potential to quantify the physical and biological changes for years or decades following enrollment. Understanding how these easements respond to restoration will provide opportunities for adaptive management, which can play a critical role in the protection, restoration, and creation of imperiled wetland ecosystems.

Year manuscript completed

2022

Year degree awarded

2022

Author's Keywords

wetland restoration, invertebrate communities, hydrological restoration

Thesis Advisor

Michael B. Flinn

Committee Chair

Howard Whiteman

Committee Member

Timothy Spier

Committee Member

Danna Baxley

Document Type

Thesis

Recommended Citation

Soldo, Christiane M. Ms., "Return of Floodplain Connectivity and Concurrent Macroinvertebrate Community Response Following Wetland Restoration in Western Kentucky" (2022). Murray State Theses and Dissertations. 263.
https://digitalcommons.murraystate.edu/etd/263