SUB-BASINAL VARIATION WITHIN LARGER WATERSHEDS: INTER-LAKE VARIABILITY AND IMPLICATIONS FOR PALEOECOLOGICAL INTERPRETATION

Shallow cores (<50 cm) from three modern, man-made freshwater lakes located within five miles of each other in south-central Missouri have yielded pollen, non-pollen palynomorphs, and dispersed organic components used to reconstruct changes in the vegetation history of the study area. Typical temperate forest pollen taxa, such as Quercus (Oak), Populus (Cottonwood), Cupressaceae, Pinus, Alnus (Alder), Ulmus (Elm), Juglans (Walnut), Carya (Hickory), and Betulaceae (Birch) are present, in addition to more open vegetation/glade pollen, including Poaceae (Grass), Asteraceae (Daisy), Plantago (Plantain), Chenopodiaceae (Goosefoot), and Ephedra (Mormon tea). Freshwater lake palynomorphs identified in the samples are mainly Potamogeton/Typha (Pondweed), desmid algae (Cosmarium, Staurastrum, Staurodesmus), colonial green algae (Botryococcus, Pediastrum), and Cyanobacteria. Despite their close geographic proximity and the many similarities between the lakes, some variations exist. Variations among temperate forest pollen, glade pollen and lake palynomorphs may be due to differences in local ecological conditions, human activities and levels of anthropogenic eutrophication within individual lakes, respectively. Ongoing data collection suggests that although paleoecological reconstruction will allow nuanced interpretation of each lake and the adjacent terrestrial environment, such interpretations may not apply to the other nearby lakes.