Historical perspectives in hydrology to understand isolated wetlands’ ecology in the Lower Flint River Basin

Details

Title:
Historical perspectives in hydrology to understand the ecology of isolated wetlands in the Lower Flint River Basin

Speaker:
Nick Marzolf, Ph.D., Assistant Scientist, The Jones Center at Ichauway

Abstract:
Wetland structure and function are largely emergent properties of hydrology and the variability of inundated conditions. In the U.S., hydrology is also core to defining legal status of wetlands at the federal level within a continuum of regulatory and conservation programs, with much recent focus on isolated wetlands. Here, we use long-term (1994 – 2023) water level data from 32 geographically isolated wetlands across Ichauway, a private research facility in the karst Dougherty Plain of southwestern Georgia, to identify spatial and temporal patterns of hydroperiod and identify drivers of inundation over the 30-year record. Wetlands at Ichauway are identified by their vegetation type as marshes, cypress-gum swamps, and cypress savannas. Wetland inundation showed distinct seasonal patterns, with typical inundation between December and the early summer. Longer-term patterns link inundation patterns to regional water availability and drought conditions. Hydroperiods in swamps were longer than in marshes and cypress savannahs and recession rates were faster in cypress savannahs and marshes compared to swamps. Across all wetlands, hydroperiods were strongly linked to variability in the regional water budget, with strong patterns with groundwater and stream water elevation, reflecting influence of both surface and belowground water on the hydrology of isolated wetlands. Our analysis leverages long-term data that spans multi-year climate cycles and informs patterns of inundation and the influence of variability in the hydrologic cycle on isolated wetlands at the landscape scale.