Date of this Version
The vascular flora of an extinct river-island and inactive northchannel of the Platte River was studied from 1972-1978. Within a variety of vegetation types, including seral and sub climax flood plain forests, 289 species were identified from 200 genera and 70 families. The flora is dominated by four families, the Poaceae, Asteraceae, Cyperaceae, and Fabaceae, which contribute 40% of the species. Forty-eight species of woody plants occur in the area, including 17 species not previously reported in Dodge County. While much of the flora is composed of forest species (36.1%), significant numbers of ruderal and marsh species (each 19.4%) are also present. Riparian and prairie species each contribute 8.3%, while meadow and pond contribute 5.5% and 2.8%, respectively. High species-richness is attributed to a favorable interaction of several variables including geological events, microclimate, river regimen, disturbance, and biological events. If significant changes in the river regimen occur in the future, changes in composition of the vegetation and flora can be expected. Species richness, particularly in aquatic areas, will decrease if provisions are not made for maintaining seasonally high-flows in the Platte River.