Aspen Bibliography

Distribution and abundance of an exotic ground-beetle (Carabidae): a test of community impact

Document Type

Article

Journal/Book Title/Conference

Oikos

Volume

62

Issue

3

First Page

351

Last Page

359

Publication Date

1991

Abstract

The distribution and wing morph proportions of Pterostichus melanarius (Ill.) and the possible effects of this exotic species on native carabid assemblages in central Alberta, Canada, were studied along pitfall trapping transects north and west out of the city of Edmonton. The species was first reported from Edmonton in 1959, but is today one of the most abundant carabids in the city and is also common up to ca. 70 km from Edmonton. The proportion of macropterous individuals of this dimorphic species increased from ca. 20% in Edmonton to 60-70% in the most distant populations, suggesting that flight is a major mode of range expansion in central Alberta. Contrary to previous studies in anthropogenic habitats, P. melanarius did not show negative pairwise associations with any of the abundant native species and was not associated with reduced numbers of species or individuals or with diminished carabid diversity in aspen-poplar forest. The success of the species in rapidly invading natural forested habitats, often viewed as less prone to invasion than are human-modified habitats, is attributed to good migratory ability of macropterous individuals, flexible habitat use and lack of biological resistance in the native assemblages.

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