Recovery of the Herb Layer in a Southern Appalachian Forest Following Chronic Herbivory by Deer (Odocoileus virginianus)


Henry M. Wilbur

Additional Authors:

Katie L. Burke Rebecca B. Wilbur Annie Rosenbauer


Sept – 2017


Deer, ground layer, herbivory, herb layer, ungulate.

ABSTRACT The high abundance of ungulates in temperate zone forests is affecting biodiversity and ecosystem functions worldwide. A randomized, replicated experiment excluded white-tailed deer, Odocoileus virginianus, from six 10310 m fenced plots for 10 years; six unfenced plots were maintained as controls. The effects of chronic herbivory were assayed by comparisons using the mean responses of ground-level vegetation in nine subplots within each of the 12 plots. Deer had a small effect on species richness but a strong effect on species prevalence, cover, and biomass, with repeatable differences in the responses of taxa to the treatments. Graminoids were favored in control plots, many other monocots and several dicots were favored in fenced plots, and parasitic plants and chemically defended herbs showed few detectable responses to fencing. The height of the vegetation represented by the shrub Vaccinium erythrocarpum and the herb Medeola virginiana was significantly taller in fenced than in control plots. This  experiment demonstrated that many forest herbs, especially those in the Liliaceae sensu lato, tolerate repeated browsing without flowering, probably for decades. When released from browsing, the time required for these species to sequester sufficient resources to flower and successfully develop seeds varied from 1 to 10 years among species. Managers of forest ecosystems must consider the impacts of game management on biodiversity.