VEGETATION SENSITIVITY DURING THE MID-HOLOCENE WARMING IN WESTERN OHIO

There has been a growing interest in prairie reconstruction in western Ohio, yet there are few recent academic sources supporting the claim that prairies appeared in western Ohio during the mid-Holocene. The hypsithermal was the warmest and driest part of the Holocene and occurred from 8,000-4,000 years ago in the Midwest. During the hypsithermal, the Prairie Peninsula appeared from Minnesota to eastern Ohio. If prairie did appear in Ohio, it occurred during the mid-Holocene hypsithermal. The goal of this study was to determine if western Ohio experienced a prairie period during the hypsithermal using pollen as a proxy for past regional vegetation. Outside of prairie reconstruction, vegetation studies are vital for climate modelling and understand an areas sensitivity to climate changes. An 8.4m sediment core was collected from Crystal Lake, Clark County, OH. There are seven zones in the Crystal Lake record, covering the Pleistocene, the early, middle, and late Holocene, the mid-Holocene hypsithermal, and the movement of homesteaders into Ohio. There are no identifiable spikes in grass, sedge, or ragweed exceeding 10%, suggesting that prairie grassland was not present around Crystal Lake during the mid-Holocene hypsithermal. The only peak of ragweed, occurring at the top of the core, likely represents the beginning of homesteading activity in the area. Based on the lack of prairie taxa, the vegetation in the Crystal Lake area was likely insensitive to the warming and drying of the hypsithermal. Although the Crystal Lake area did experience a shift in vegetation in response to the hypsithermal, it was not a shift from deciduous forest to a prairie. The vegetation in the Crystal Lake area will likely remain insensitive and the vegetation is likely not to experience any large changes in response to ongoing climate change.