RECONSTRUCTING BASELINES IN A RESTORED FLOODPLAIN: AN EXAMINATION OF AQUATIC VEGETATION IN THE EMIQUON PRESERVE, LEWISTOWN ILLINOIS

Historically, Thompson and Flag Lakes, were among the most productive freshwater systems in the country. Additionally, they provided habitat for a tremendous number of water fowl and migrating bird species. In the 1920’s, these lakes were drained and the land converted over to agriculture production. In 2007, The Nature Conservancy (TNC), established the Emiquon Preserve and began the process of restoring the lakes. Beginning later this year (2016), TNC hopes to begin to manage the water, and will periodically be drawing the water level down, to better match what would occur in nature and lead to a healthier system.

In seeking to restore the Emiquon area, and to successfully manage the project, questions remain about baseline conditions and how much variability is natural within the system. To resolve these concerns, it is necessary to apply historic information and paleontological data.

Historical information spanning a range of temporal scales—tens to millions of years—can influence restoration practice by providing context for understanding modern systems. Unfortunately, for most systems little historic data exist which can be applied. Conservation paleobiology can be utilized to help fill in the gaps in our knowledge of historic and pre-historic conditions by utilizing the shallow and deep fossil record. It is necessary, however, to assess the level of bias which might be present in these records through studies comparing the living community with what is preservable in the system.

Submerged aquatic vegetation, moist soil vegetation, and emergent vegetation are key ecological indicators of the health of a wetland, and critical for examining the success of the restoration at Emiquon. Since the start of the restoration, surveys have been conducted to characterize these communities. In addition to these surveys, short core samples have been collected with which to asses seed production. These cores represent the first step in identifying bias between the living vegetation communities and what may be preserved in the historic floodplain deposits. Initial results indicate that a great deal of information about the living community is preserved in the seed bank as measured by richness, evenness, and similarity metrics.