Effects of an exotic species, the European wild boar (Sus scrofa Linneaus) on the vegetational structure and the small mammal community of the oak /hickory forests of the Great Smoky Mountains National Park.

摘要

I compared vegetational characteristics and small mammal communities of two similar oak/hickory forests: one occupied by exotic European wild boars (Sus scrofa Linneaus) within the boundaries of the Great Smoky Mountains National Park, and one in similar areas outside of park boundaries where wild boars are absent.;For vegetational comparisons, I used oak/hickory abundance and species diversity to compare vegetational components. For structural comparison, I used ground coverage, stems per unit area, and ground surface disturbance per unit area associated with wild boar occupation.;I determined that oak/hickory abundance and species diversity of the overstory components were not different. However, oak/hickory abundance and species diversity of the sapling and seedling components were significantly lower in areas occupied by the wild boars. In the sapling and seedling components, oak/hickory abundance and species diversity appear to be positively correlated with presence of ground cover and negatively correlated with disturbance. Presence of the wild boars has resulted in (1) disruption of the normal vegetational recruitment cycle of mast producing species, (2) reduction of vegetational diversity, and (3) reduction of ground cover in the oak/hickory forests of the Great Smoky Mountains National Park.;To determine effects of coexistence with the wild boars, I used the most prevalent small mammal in the oak/hickory forest, the white-footed mouse ( Peromyscus leucopus), as an indicator species. I examined estimated density of the indicator species in relation to mast production, average weight of the indicator species, the number of juveniles present, the number of reproductively mature individuals present, and dispersal of the indicator species to compare the two populations.;Community comparisons indicate that coexistence with the wild boars has a significant negative effect on the indicator species population inhabiting the Great Smoky Mountains National Park. Another small mammal, the eastern chipmunk (Tamias striatus), appears to be completely absent from the Great Smoky Mountains National Park survey sites where wild boar densities have been the highest. Results were consistent with initial predictions that preferential mast consumption by wild boars, coupled with collateral rooting damage, has a deleterious effect on the small mammal community.;This study indicates that the exotic European wild boar is a keystone species, and that its presence negatively effects both the vegetational structure and the small mammal community of the oak/hickory forests of the Great Smoky Mountains National Park.