PS 18-139
Effect of an invasive species on surface and ground water levels of a wet prairie
The Oak Openings Region in Northwest Ohio originally consisted of oak savannas, wet prairies, oak woodlands, oak barrens and floodplain forests. Currently, the Oak Openings supports globally rare oak savanna and wet prairie habitats, and it is home to more rare species of plants and animals than any other area in Ohio. The wet prairies in the region have been drained by ditches and encroached by invasive plants (mainly glossy buckthorn - Rhamnus frangula). Furthermore, the hydrologic characteristics of the Oak Openings Region are not well understood. This is partly due to lack of hydrologic research in the area, and partly due to the complexity of the system.
What is the effect of the removal of buckthorn on the water table? What is the interaction between the ditch and the water table in the restoration areas? What is the basic hydrology of the wet prairie system in this altered landscape?
Groundwater and ditch levels are monitored at six wet prairie restoration sites. Each site consists of a clustered set of five piezometers positioned on a transect perpendicular to the main ditch at different depths. Within each ditch reach, a surface water monitoring location is also set. The sites have been monitored twice weekly during the growing season and weekly otherwise for almost three years.
Results/Conclusions
Results show a different response in the groundwater levels of sites where buckthorn is present compared to the locations where it is not present. Particularly, the longer growing season of the buckthorn is depressing groundwater levels until the beginning of November. The response of the shallow groundwater to precipitation events is very rapid. The groundwater levels rise in a matter of hours after precipitation events, stabilizing less than a day after an event.