Date of Award

2013

Degree Type

Dissertation

Department

Biological, Geological and Environmental Sciences

First Advisor

Walton, B. Michael

Subject Headings

White-tailed deer -- Ohio, Odocoileus -- Ohio, Forest ecology -- Ohio, white-tailed deer small mammals arthropods non-native overabundance

Abstract

Browsing by white-tailed deer has alters plant species diversity of the forest understory across much of North America. A reduced understory may lead to the simplification of the forest-floor microhabitat, causing broad scale shifts in the community composition and abundance of litter-dwelling arthropods and small mammals. The objectives of this study were to 1) document changes in the forest-floor microhabitat as a result of over-browsing by deer and 2) determine if differential browsing pressures indirectly affect faunal biodiversity (litter-dwelling arthropods and small mammals) of forest ecosystems. I predicted that browsing within the understory will reduce structural complexity of the forest-floor microhabitat, and its dependent community. A combination of comparative (high vs. low deer impact) and exclosure studies were used to document the effects of herbivory on forest ecosystems. Fewer seedlings and less herbaceous and canopy cover occurred in areas outside exclosures and in areas heavily impacted by deer in contrast to those impacted less, and as percent herbaceous cover correlated strongly with leaf litter biomass and depth, browsing reduces structural complexity of the forest-floor microhabitat. More mesofauna, Coleoptera and Araneae, were present inside than outside deer exclosures. Non-native species (i.e., centipedes, gastropods, isopods and millipedes) were more abundant in areas of high deer impact compared to areas of lower impact. No differences in small mammal abundance were detected in response to the indirect effects of browsing however, areas of low impact were more speciose and supported significantly more insectivorous small mammals (Soricidae). Soricids require moist habitats with adequate cover and ample invertebrate prey. Capture rates of the Masked Shrew, Sorex cinereus, were positively correlated with litter depth and invertebrate abundance of the preceding year. These findings suggest that even where total soricid and arthropod abundance did not vary in response to diff

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