Citation. Ovington, J. D. 1965. Prairie, savanna and oakwood ecosystems at Cedar Creek. Pages 43-53 in D. J. Crisp, editor. Grazing in Terrestrial and Marine Environments. Symp. Brit. Ecol. Soc.   [1457  CC]

Abstract. On the upland, sandy soils of the Cedar Creek Natural History Area, Minnesota, examples of semi-natural prairie, savanna and oakwood occur in juxtaposition and present a unique opportunity to make ecological comparisons of ecosystems with different degrees of tree cover. Typical examples of each ecosystem type were studied intensively at monthly intervals from May to November, 1959. Although the inherent site conditions were not identical at all three study areas, it seemed that the form of the vegetation cover was of greatest importance in influencing the magnitude and pattern of ecosystem dynamics. With increasing numbers of shrubs and trees present, the magnitude of the organic system and nutrient circulation increased greatly, suggesting that the presence of woody plants results in a greater utilization of the site and increased biological activity. The primary productivity of the oakwood was not greatly different from that of an intensively managed field of maize nearby; hence the woodland was probably making very full use of the site. The savanna ecosystem, which was relatively rich in the plant nutrients nitrogen, potassium, calcium, magnesium and phosphorus, produced the largest mass of plant material at ground level.

Keywords. prairie, savanna, oakwood, primary productivity