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High white-tailed deer density has negative impact on tallgrass prairie forbs1
ANDERSON, R. C., E. A. CORBETT, M. R. ANDERSON, G. A. CORBETT, AND T M. KELLEY (4120-Department of Biological Sciences, Behavior, Ecology, Evolution, and Systematics Section, Illinois State University, Normal, Illinois 61790-4120). High white tailed deer density has negative impact on tallgrass prairie forbs. J. Torrey Bot. Soc. 128:381-392, 2001.-We studied the effect of deer browsing on prairie forbs under conditions of high deer density (30 to 42 deer km^sup -2^) on a single remnant tallgrass prairie in the Illinois Department of Natural Resources' Heidecke Lake Fish and Wildlife Area in northeastern Illinois. Almost no grasses or sedges were browsed and the frequency of browsing of graminoids was nearly the same in deer exclosure and reference plots. In contrast, deer browsed 3.5% to 18.9% of the standing crop of forb stems depending upon time of sampling. Deer selectively browsed 26% percent of the 100 species of forbs sampled in at least one of nine samples taken over three growing seasons. However, most species (17 of 26 selected species) were selected in only one sample. Highest browsing intensity occurred during late June and early July. Flowering stems of 3 species of forbs were significantly less abundant in the reference plots than in the exclosure plots, indicating a potentially adverse effect of deer browsing on the reproductive success of these prairie forbs. Deer are most likely to influence prairie vegetation by causing a shift in plant species abundance and competitive abilities in a way that favors grasses over forbs and reduces prairie plant diversity.
Key words: Odocoileus virginianus, tallgrass prairie, forbs, browsing, Illinois.
White-tailed deer (Odocoileus virginianus) and other large herbivores have a substantial influence on vegetation diversity (Alverson et al. 1988; McNaughton et al. 1988; Pastor et al. 1988; Anderson 1994a; Collins et al. 1998; Knapp et al. 1999). However, most studies considered the effects of deer browsing on forest trees or understory vegetation (Beals et al. 1960; Anderson and Loucks 1979; Frelich and Lorimer 1985; Alverson et al. 1988; Anderson and Katz 1993; Anderson 1994a, 1997; Balgooyen and Walter 1995; Rooney 1997; Waller and Alverson 1997; Augustine and Frelich 1998; Williams et al. 1999; Webster and Parker 2000). In contrast, there is...