Degree Name

Master of Science (MS)

Semester of Degree Completion

1996

Thesis Director

Thomas A. Nelson

Abstract

The Illinois Department of Natural Resources currently manages approximately 4,000 hectares of natural prairie. High human impacts coupled with small patch size result in challenging management decisions for prairie conservation. The ideal restored prairie would consist of a mosaic of habitats varying in vegetation from forb-grass dominated areas to oak savannas, with concurrent stages of vegetative succession occurring across the habitats. A study was conducted at the Middle Fork State Fish and Wildlife Area located in Vermillion County, IL, to analyze small mammal diversity and community composition among three different stages of prairie restoration.

The three treatment categories were: fallow fields (non-prairie areas typified by non-flowering vegetation and cool season grasses); forb fields (1-2 year restored prairies dominated by forbs and warm season grasses); and established fields (9 year and older restored tallgrass prairies dominated by warm season grasses with some forbs). Data were collected during three separate trapping periods in May/June and August 1995, and January 1996. Each field was trapped for three consecutive nights during each trap season for a total of nine nights per field.

A total of 312 small mammals of six different species were captured. Small mammal species included Peromyscus maniculatus, Peromyscus leucopus, Zapus hudsonius, Mus musculus, Reithrodontomys megalotis and Microtus ochrogaster. Results indicated an association between vegetational diversity and small mammal diversity, with forb fields having both highest vegetational diversity and small mammal diversity. Peromyscus maniculatus was found at high densities in the fallow fields, where small mammal diversity was lowest. Zapus hudsonius occurred only in forb fields, suggesting a strong habitat preference for this successional stage. Microtus ochrogaster had significantly higher densities in the forb fields, compared to the fallow and established fields, also indicating a strong habitat preference.

Grassland management techniques, such as mowing and prescribed burning, may have either negative or positive short-term impacts on the densities of residential small mammal populations depending on the species. Peromyscus leucopus responded negatively to mowing. Population densities of this species were lowest after mowing. Mus musculus may have benefited temporarily from prescribed fires. Populations of this species increased, perhaps due to decreased interspecific competition with P. maniculatus after burning. Managing natural and restored prairies as a mosaic of successional stages may be necessary to retain a full complement of native small mammals.

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