PARENT SESSION
Poster Session 30: Invertebrate Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Ground beetles (Coleoptera: Carabidae) along a successional gradient: how important are introduced species?
Mercado Cárdenas, Alida*,1, Buddle, Christopher1, 1 McGill University, Ste. Anne de Bellevue, Quebec, Canada
ABSTRACT- The objective of this project is to study the diversity and community assemblages of ground beetles along a successional gradient (old-growth forests, young forests, old pastures, agricultural fields), and to assess the role of introduced species within these habitats. Beetles were collected with pitfall traps at and around the Morgan Arboretum (Montreal, Quebec) in 2003 and 2004. Fifty-five species (2635 individuals) were found in 2003 and 50 species (1746 individuals) in 2004. The highest species richness was found in the cornfields and our results show that abundance of carabids was significantly higher in the agricultural fields than in other habitats. The estimated number of ground beetle species, as determined by rarefaction, was highest in young forests in 2003 and agricultural fields in 2004. Eight species from 2003, and five species from 2004 are introduced, and their abundance was greater than that of native species in both years. Patterns of community composition, as analyzed with Nonmetric Multidimensional Scaling, showed an aggregation of agricultural fields both years and other sites were more scattered. Old pastures differentiated from agricultural fields when the introduced species were removed from the analysis. The native fauna of old-fields is therefore distinct, and differences in their composition are lessened in the presence of introduced species. The fauna of young forests and old-forests, however, were less affected by introduced species. Although introduced species are numerically dominant along the successional gradient, they are primarily associated with anthropogenic habitats, and have yet to disrupt the ground beetle community from forested habitats within our study area.
Key words: ground beetles, introduced species