Date of Award

8-1-1967

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

Abstract

Daily movements of two adjacent microtine populations were correlated with the utilization of various types of microenvironments. Animals were trapped, marked and released on a gridded area which transected three ecological zones, a riparian woodland, an edge, and an old field. Average distance traveled between recaptures and standard diameters were used to estimate activity patterns and home ranges of the meadow vole, ..Microtus oennsylvanicus, and the red-backed vole, Clethrionomys gapperi. Microtus restricted their activity to grassy habitats while Clethrionomys remained in the woodland. There was no ecological overlap between the two species. In spite of relatively high population densities, meadow and red-backed voles restricted activities to their preferred grassy and wooded habitats. Despite intraspecific population pressure, interspecific competition was an important factor restricting these species to their respective habitats.

Periods of precipitation or drought temporarily affected the activity patterns of meadow voles. The number of captures increased immediately following precipitation; dry periods had the opposite effect. These conditions had no apparent effect on the activity of Clethrionomys. However, there was no positive correlation between periods of precipitation and the average distances traveled by either species on successive days.

In general, Clethrionomys had larger home ranges than Microtus. Adults of both species had larger home ranges than juveniles; therefore, they appeared to disperse further than juveniles.

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