Degree Name

Master of Science (MS)

Semester of Degree Completion

1975

Thesis Director

Richard D. Andrews

Abstract

Parts of three major streams in east central Illinois: the Embarrass, the Kaskaskia and Okaw Rivers were cruised during the fall of 1973 and the summer and fall of 1974. Beaver (Castor canadensis) sign were located and recorded. A qualitative analysis of the woody vegetation on the Kaskaskia and Okaw Rivers was undertaken.

Two activity sites were located on the Embarrass. Three fresh and three old cutting sites were located on the Kaskaskia in 1973; in 1974, five fresh sites were found. The Okaw had six fresh and six old cutting sites in 1973, but in 1974, only one fresh site was found. Silver maple (Acer saccharinum) had the highest IVI on the Embarrass, whereas cottonwood (Populus deltoides) was the most predominant on the Kaskaskia and Okaw Rivers.

The Embarrass River supports minimal populations of beaver due to the high density and low utilization of maple and fluctuating water levels. A reservoir should stabilize water levels and permit beaver to utilize the habitat more efficiently by making more trees accessible. Beaver activity at Lake Shelbyville, based on sign of cutting, has exhibited a pattern related to changes in water levels of the lake. All activity was found at the water-land interface where suitable food was present. Therefore, high water levels forced the beaver upstream and to margins where food was available, affecting the populations by killing vast amounts of prime timber and probably drowning many kits born in the spring. Greatly fluctuating water levels in the lake will eventually destroy the beaver population; however, if water levels are stabilized, the population will probably flourish in upstream areas where food is available.

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